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1

Joule-Thomson expander and heat exchanger  

NASA Technical Reports Server (NTRS)

The Joule-Thomson Expander and Heat Exchanger Program was initiated to develop an assembly (JTX) which consists of an inlet filter, counterflow heat exchanger, Joule-Thomson expansion device, and a low pressure jacket. The program objective was to develop a JTX which, when coupled to an open cycle supercritical helium refrigerating system (storage vessel), would supply superfluid helium (He II) at 2 K or less for cooling infrared detectors.

Norman, R. H.

1976-01-01

2

Optimal joule heating of the subsurface  

DOEpatents

A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Berryman, J.G.; Daily, W.D.

1994-07-05

3

Optimal joule heating of the subsurface  

DOEpatents

A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Berryman, James G. (Danville, CA); Daily, William D. (Livermore, CA)

1994-01-01

4

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

Biesheuvel, P M; Hamelers, H V M

2014-01-01

5

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

P. M. Biesheuvel; D. Brogioli; H. V. M. Hamelers

2014-02-06

6

Nonlinear phenomena in multiferroic nanocapacitor: Joule heating and electromechanical effects  

SciTech Connect

We demonstrate an approach for probing nonlinear electromechanical responses in BiFeO3 thin film nanocapacitors using half-harmonic band excitation piezoresponse force microscopy (PFM). Nonlinear PFM images of nanocapacitor arrays show clearly visible clusters of capacitors associated with variations of local leakage current through the BiFeO3 film. Strain spectroscopy measurements and finite element modeling point to significance of the Joule heating and show that the thermal effects caused by the Joule heating can provide nontrivial contributions to the nonlinear electromechanical responses in ferroic nanostructures. This approach can be further extended to unambiguous mapping of electrostatic signal contributions to PFM and related techniques.

Kim, Yunseok [ORNL; Kumar, Amit [ORNL; Tselev, Alexander [ORNL; Kravchenko, Ivan I [ORNL; Kalinin, Sergei V [ORNL; Jesse, Stephen [ORNL

2011-01-01

7

Joule heating of solid wires in MAG welding  

Microsoft Academic Search

There are numerous studies concerning the melting rate of welding wire and various investigations have been carried out on welding current, welding current waveform, wire extension, polarity, chemical composition, wire diameter, arc length, shielding gas composition and melting rate. Joule heating of bulk wire has been a large contributory factor to the melting rate of solid wire for carbon steel

H. Shimizu; Y. Yokota; T. Itoh; T. Kurokawa; M. Ushio

2005-01-01

8

Joule heating of a titanium rod  

NSDL National Science Digital Library

Use the steady-state heat conduction solution for constant heat generation in a rod to determine the maximum temperature difference between the center and surface of a titanium rod heated by electric current; also sketch temperature history from the time when current is turned on.

Powell, Adam C., IV

2002-10-04

9

Joule heating and current-induced domain wall motion  

NASA Astrophysics Data System (ADS)

We investigate numerically and experimentally the Joule heating produced by current pulses and its contribution to current-induced domain wall (DW) motion in a (Ga,Mn)As ferromagnetic semiconductor. Different thermal coupling between tracks and substrates are explored. A direct contact leads to a logarithmic transient temperature rise and a stationary state determined by the substrate thickness. The introduction of a low thermal conducting (Ga,In)As interlayer produces an additional temperature rise whose time variation and magnitude are analyzed. Experimentally, the measured temperature rises present a good agreement with predictions over more than four orders of magnitude in time for values of the heat conductivity and of the heat capacity close to those reported in the literature. The Joule heating is shown to produce non-linearities in the domain wall velocity versus current density characteristics. A correction of Joule heating is proposed and permits the identification of the flow regimes from a comparison of domain-wall dynamics in tracks presenting different pinning characteristics.

Curiale, J.; Lemaître, A.; Niazi, T.; Faini, G.; Jeudy, V.

2012-11-01

10

Loop formation in graphitic nanoribbon edges using furnace heating or Joule heating  

E-print Network

Here the authors report the use of either furnace heating or Joule heating to pacify the exposed graphene edges by loop formation in a novel graphitic nanoribbonmaterial, grown by chemical vapor deposition. The edge energy ...

Jia, Xiaoting

11

Joule heating in packed capillaries used in capillary electrochromatography.  

PubMed

Effective heat dissipation is critical for reproducible and efficient separations in electrically driven separation systems. Flow rate, retention kinetics, and analyte diffusion rates are some of the characteristics that are affected by variation in the temperature of the mobile phase inside the column. In this study, we examine the issue of Joule heating in packed capillary columns used in capillary electrochromatography (CEC). As almost all commonly used CEC packings are poor thermal conductors, it is assumed that the packing particles do not conduct heat and heat transfer is solely through the mobile phase flowing through the system. The electrical conductivity of various mobile phases was measured at different temperatures by a conductivity meter and the temperature coefficient for each mobile phase was calculated. This was followed by measurement of the electrical current at several applied voltages to calculate the conductivity of the solution within the column as a function of the applied voltage. An overall increase in the conductivity is attributed to Joule heating within the column, while a constant conductivity means good heat dissipation. A plot of conductivity versus applied voltage was used as the indicator of poor heat dissipation. Using theories that have been proposed earlier for modeling of Joule heating effects in capillary electrophoresis (CE), we estimated the temperature within CEC columns. Under mobile and stationary phase conditions typically used in CEC, heat dissipation was found to be not always efficient. Elevated temperatures within the columns in excess of 23 degrees C above ambient temperature were calculated for packed columns, and about 35 degrees C for an open column, under a given set of conditions. The results agree with recently published experimental findings with nuclear magnetic resonance (NMR) thermometry, and Raman spectroscopic measurements. PMID:12207300

Rathore, Anurag S; Reynolds, Kimberly J; Colón, Luis A

2002-09-01

12

On Joule heating of the equatorial electrojet E-region  

Microsoft Academic Search

Simultaneous data on electron density, electron temperature and current density obtained from a rocket borne Langmuir probe, a glass-sealed Langmuir probe and a proton precession magnetometer flown from Thumba (geomag. lat. 0.99 deg S, geomag. long. 146.79 deg E, magnetic dip of 0 deg 47 min S) have been used to calculate the Joule heating in order to assess whether

R. Jain; N. Nath; C. S. G. K. Setty

1981-01-01

13

Joule heating of Io's ionosphere by unipolar induction currents  

NASA Technical Reports Server (NTRS)

Electrical induction in Io's ionosphere, due to the corotating plasma bound to the Jovian magnetosphere, is one possible source for the attainment of the high temperatures suggested by the large scale height of Io's ionosphere. Unipolar induction models are constructed to calculate ionospheric joule heating numerically, whose heating rates lie between 10 to the -9th and 10 to the -8th W/cu m. The binding and coupling of the ionosphere is due to the dense, and possibly ionized, neutral SO2 atmosphere, and there appears to be no need to postulate the existence of an intrinsic Ionian magnetic field in order to retain the observed ionnosphere.

Herbert, F.; Lichtenstein, B. R.

1980-01-01

14

Acceleration of runaway electrons and Joule heating in solar flares  

NASA Technical Reports Server (NTRS)

The electric field acceleration of electrons out of a thermal plasma and the simultaneous Joule heating of the plasma are studied. Acceleration and heating timescales are derived and compared, and upper limits are obtained on the acceleration volume and the rate at which electrons can be accelerated. These upper limits, determined by the maximum magnetic field strength observed in flaring regions, place stringent restrictions upon the acceleration process. The role of the plasma resistivity in these processes is examined, and possible sources of anomalous resistivity are summarized. The implications of these results for the microwave and hard X-ray emission from solar flares are examined.

Holman, G. D.

1984-01-01

15

Acceleration of runaway electrons and Joule heating in solar flares  

NASA Technical Reports Server (NTRS)

The electric field acceleration of electrons out of a thermal plasma and the simultaneous Joule heating of the plasma are studied. Acceleration and heating timescales are derived and compared, and upper limits are obtained on the acceleration volume and the rate at which electrons can be accelerated. These upper limits, determined by the maximum magnetic field strength observed in flaring regions, place stringent restrictions upon the acceleration process. The role of the plasma resistivity in these processes is examined, and possible sources of anomalous resistivity are summarized. The implications of these results for the microwave and hard X-ray emission from solar flares are examined.

Holman, G. D.

1985-01-01

16

Physical and numerical modeling of Joule-heated melters  

NASA Astrophysics Data System (ADS)

The Joule-heated ceramic-lined melter is an integral part of the high level waste immobilization process under development by the US Department of Energy. Scaleup and design of this waste glass melting furnace requires an understanding of the relationships between melting cavity design parameters and the furnace performance characteristics such as mixing, heat transfer, and electrical requirements. Developing empirical models of these relationships through actual melter testing with numerous designs would be a very costly and time consuming task. Additionally, the Pacific Northwest Laboratory (PNL) has been developing numerical models that simulate a Joule-heated melter for analyzing melter performance. This report documents the method used and results of this modeling effort. Numerical modeling results are compared with the more conventional, physical modeling results to validate the approach. Also included are the results of numerically simulating an operating research melter at PNL. Physical Joule-heated melters modeling results used for qualiying the simulation capabilities of the melter code included: (1) a melter with a single pair of electrodes and (2) a melter with a dual pair (two pairs) of electrodes. The physical model of the melter having two electrode pairs utilized a configuration with primary and secondary electrodes. The principal melter parameters (the ratio of power applied to each electrode pair, modeling fluid depth, electrode spacing) were varied in nine tests of the physical model during FY85. Code predictions were made for five of these tests. Voltage drops, temperature field data, and electric field data varied in their agreement with the physical modeling results, but in general were judged acceptable.

Eyler, L. L.; Skarda, R. J.; Crowder, R. S., III; Trent, D. S.; Reid, C. R.; Lessor, D. L.

1985-10-01

17

ULF wave electromagnetic energy flux into the ionosphere: Joule heating implications  

NASA Astrophysics Data System (ADS)

Ultralow-frequency (ULF) waves—in particular, Alfvén waves-transfer energy into the Earth's ionosphere via Joule heating, but it is unclear how much they contribute to global and local heating rates relative to other energy sources. In this study we use Time History of Events and Macroscale Interactions during Substorms satellite data to investigate the spatial, frequency, and geomagnetic activity dependence of the ULF wave Poynting vector (electromagnetic energy flux) mapped to the ionosphere. We use these measurements to estimate Joule heating rates, covering latitudes at or below the nominal auroral oval and below the open/closed field line boundary. We find ULF wave Joule heating rates (integrated over 3-30 mHz frequency band) typically range from 0.001 to 1 mW/m2. We compare these rates to empirical models of Joule heating associated with large-scale, static (on ULF wave timescales) current systems, finding that ULF waves nominally contribute little to the global, integrated Joule heating rate. However, there are extreme cases with ULF wave Joule heating rates of ?10 mW/m2—in these cases, which are more likely to occur when Kp ? 3, ULF waves make significant contributions to the global Joule heating rate. We also find ULF waves routinely make significant contributions to local Joule heating rates near the noon and midnight local time sectors, where static current systems nominally contribute less to Joule heating; the most important contributions come from lower frequency (<7 mHz) waves.

Hartinger, M. D.; Moldwin, M. B.; Zou, S.; Bonnell, J. W.; Angelopoulos, V.

2015-01-01

18

Electro-osmotic infusion for joule heating soil remediation techniques  

DOEpatents

Electro-osmotic infusion of ground water or chemically tailored electrolyte is used to enhance, maintain, or recondition electrical conductivity for the joule heating remediation technique. Induced flows can be used to infuse electrolyte with enhanced ionic conductivity into the vicinity of the electrodes, maintain the local saturation of near-electrode regions and resaturate a partially dried out zone with groundwater. Electro-osmotic infusion can also tailor the conductivity throughout the target layer by infusing chemically modified and/or heated electrolyte to improve conductivity contrast of the interior. Periodic polarity reversals will prevent large pH changes at the electrodes. Electro-osmotic infusion can be used to condition the electrical conductivity of the soil, particularly low permeability soil, before and during the heating operation. Electro-osmotic infusion is carried out by locating one or more electrodes adjacent the heating electrodes and applying a dc potential between two or more electrodes. Depending on the polarities of the electrodes, the induced flow will be toward the heating electrodes or away from the heating electrodes. In addition, electrodes carrying a dc potential may be located throughout the target area to tailor the conductivity of the target area.

Carrigan, Charles R. (Tracy, CA); Nitao, John J. (Castro Valley, CA)

1999-01-01

19

Refractory electrodes for joule heating and methods of using same  

DOEpatents

A certain group of electrically conductive refractory materials presently known for use in high temperature applications as throat constructions, melter sidewalls, forehearth, stacks, port sills, hot face lining for slagging coal gasifiers, slag runners, and linings for nuclear waste encapsulation furnaces may be used as electrodes permitting joule heating at temperatures in excess of 1200 C. in excess of about 4400 hours even in the presence of transition group element(s). More specifically, the invention is an electrode for melting earthen materials, wherein the electrode is made from an electrically conductive refractory material, specifically at least one metal oxide wherein the metal is selected from the group consisting of chrome, ruthenium, rhodium, tin and combinations thereof.

Lamar, David A. (West Richland, WA); Chapman, Chris C. (Richland, WA); Elliott, Michael L. (Kennewick, WA)

1998-01-01

20

Refractory electrodes for joule heating and methods of using same  

DOEpatents

A certain group of electrically conductive refractory materials presently known for use in high temperature applications as throat constructions, melter sidewalls, forehearth, stacks, port sills, hot face lining for slagging coal gasifiers, slag runners, and linings for nuclear waste encapsulation furnaces may be used as electrodes permitting joule heating at temperatures in excess of 1,200 C in excess of about 4400 hours even in the presence of transition group element(s). More specifically, the invention is an electrode for melting earthen materials, wherein the electrode is made from an electrically conductive refractory material, specifically at least one metal oxide wherein the metal is selected from the group consisting of chrome, ruthenium, rhodium, tin and combinations thereof. 2 figs.

Lamar, D.A.; Chapman, C.C.; Elliott, M.L.

1998-05-12

21

Joule heating and runaway electron acceleration in a solar flare  

NASA Technical Reports Server (NTRS)

The hard and soft x ray and microwave emissions from a solar flare (May 14, 1980) were analyzed and interpreted in terms of Joule heating and runaway electron acceleration in one or more current sheets. It is found that all three emissions can be generated with sub-Dreicer electric fields. The soft x ray emitting plasma can only be heated by a single current sheet if the resistivity in the sheet is well above the classical, collisional resistivity of 10(exp 7) K, 10(exp 11)/cu cm plasma. If the hard x ray emission is from thermal electrons, anomalous resistivity or densities exceeding 3 x 10(exp 12)/cu cm are required. If the hard x ray emission is from nonthermal electrons, the emissions can be produced with classical resistivity in the current sheets if the heating rate is approximately 4 times greater than that deduced from the soft x ray data (with a density of 10(exp 10)/cu cm in the soft x ray emitting region), if there are at least 10(exp 4) current sheets, and if the plasma properties in the sheets are characteristic of the superhot plasma observed in some flares by Lin et al., and with Hinotori. Most of the released energy goes directly into bulk heating, rather than accelerated particles.

Holman, Gordon D.; Kundu, Mukul R.; Kane, Sharad R.

1989-01-01

22

Fluid flow and heat transfer in Joule-Thomson coolers coupled with infrared detectors  

NASA Astrophysics Data System (ADS)

Joule-Thomson coolers have been widely used in infrared detectors with respect to compact, light and low cost. For self-regulating Joule-Thomson cooler, its performance is required to be improved with the development of higher mass and larger diameter of focal plane infrared detectors. Self-regulating Joule-Thomson coolers use a limited supply of high pressure gas to support the cooling of infrared detectors. In order to develop Joule-Thomson coolers with a given volume of stored gas, it is important to study on fluid flow and heat transfer of Joule-Thomson coolers coupled with infrared detectors, especially the starting time of Joule-Thomson coolers. A serial of experiments of Joule-Thomson coolers coupled with 128×128 focal plane infrared detectors have been carried out. The exchanger of coolers are made of a d=0.5mm capillary finned with a copper wire. The coolers are self-regulated by bellows and the diameters are about 8mm. Nitrogen is used as working gas. The effect of pressure of working gas has been studied. The relation between starting time and pressure of working gas is proved to fit exponential decay. Error analysis has also been carried. It is crucial to study the performance of Joule-Thomson coolers coupled with infrared detectors. Deeper research on Joule-Thomson coolers will be carried on to improve the Joule-Thomson coolers for infrared detectors.

Du, Bingyan; Jia, Weimin

2011-08-01

23

Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei  

E-print Network

Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei-II superconductor due to Joule heating induced by vortex motion. The effect of Joule heating is detected to the power dissipated by the vortex motion. DOI: 10.1103/PhysRevB.64.094511 PACS number s : 74.60.Ec, 65

Andrei, Eva Y.

24

Interplanetary magnetic field and solar cycle dependence of Northern Hemisphere F region joule heating  

NASA Astrophysics Data System (ADS)

Joule heating in the ionosphere takes place through collisions between ions and neutrals. Statistical maps of F region Joule heating in the Northern Hemisphere polar ionosphere are derived from satellite measurements of thermospheric wind and radar measurements of ionospheric ion convection. Persistent mesoscale heating is observed near postnoon and postmidnight magnetic local time and centered around 70° magnetic latitude in regions of strong relative ion and neutral drift. The magnitude of the Joule heating is found to be largest during solar maximum and for a southeast oriented interplanetary magnetic field. These conditions are consistent with stronger ion convection producing a larger relative flow between ions and neutrals. The global-scale Joule heating maps quantify persistent (in location) regions of heating that may be used to provide a broader context compared to small-scale studies of the coupling between the thermosphere and ionosphere.

Bjoland, L. M.; Chen, X.; Jin, Y.; Reimer, A. S.; Skjæveland, Å.; Wessel, M. R.; Burchill, J. K.; Clausen, L. B. N.; Haaland, S. E.; McWilliams, K. A.

2015-02-01

25

Heat, work and subtle fluids: a commentary on Joule (1850) ‘On the mechanical equivalent of heat  

PubMed Central

James Joule played the major role in establishing the conservation of energy, or the first law of thermodynamics, as a universal, all-pervasive principle of physics. He was an experimentalist par excellence and his place in the development of thermodynamics is unarguable. This article discusses Joule's life and scientific work culminating in the 1850 paper, where he presented his detailed measurements of the mechanical equivalent of heat using his famous paddle-wheel apparatus. Joule's long series of experiments in the 1840s leading to his realisation that the conservation of energy was probably of universal validity is discussed in context with the work of other pioneers, notably Sadi Carnot, who effectively formulated the principle of the second law of thermodynamics a quarter of a century before the first law was accepted. The story of Joule's work is a story of an uphill struggle against a critical scientific establishment unwilling to accept the mounting evidence until it was impossible to ignore. His difficulties in attracting funding and publishing in reputable journals despite the quality of his work will resonate with many young scientists and engineers of the present day. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750152

Young, John

2015-01-01

26

Joule heating induced by vortex motion in a type-II superconductor  

SciTech Connect

We present experiments that determine the temperature increase in a type-II superconductor due to Joule heating induced by vortex motion. The effect of Joule heating is detected by comparing the response of the vortex lattice to fixed amplitude current steps of short (10 {mu}s) and long (4 s) duration, where the Joule heating is negligible and saturates, respectively. The thermometry is based on the temperature dependence of the voltage response of the vortex lattice to a driving current. By monitoring the temperature increase in NbSe{sub 2} samples adhered on a sapphire substrate with GE varnish we obtain the effective heat transfer coefficient between the sample and the bath and show that the heating is primarily due to the power dissipated by the vortex motion.

Xiao, Z. L.; Andrei, E. Y.; Shuk, P.; Greenblatt, M.

2001-09-01

27

Hybrid joule heating/electro-osmosis process for extracting contaminants from soil layers  

DOEpatents

Joule (ohmic) heating and electro-osmosis are combined in a hybrid process for removal of both water-soluble contaminants and non-aqueous phase liquids from contaminated, low-permeability soil formations that are saturated. Central to this hybrid process is the partial desaturation of the formation or layer using electro-osmosis to remove a portion of the pore fluids by induction of a ground water flow to extraction wells. Joule heating is then performed on a partially desaturated formation. The joule heating and electro-osmosis operations can be carried out simultaneously or sequentially if the desaturation by electro-osmosis occurs initially. Joule heating of the desaturated formation results in a very effective transfer or partitioning of liquid state contaminants to the vapor phase. The heating also substantially increases the vapor phase pressure in the porous formation. As a result, the contaminant laden vapor phase is forced out into soil layers of a higher permeability where other conventional removal processes, such as steam stripping or ground water extraction can be used to capture the contaminants. This hybrid process is more energy efficient than joule heating or steam stripping for cleaning low permeability formations and can share electrodes to minimize facility costs.

Carrigan, Charles R.; Nitao, John J.

2003-06-10

28

Estimation of Joule heating effect on temperature and pressure distribution in electrokinetic-driven microchannel flows.  

PubMed

In this study we present simple analytical models that predict the temperature and pressure variations in electrokinetic-driven microchannel flow under the Joule heating effect. For temperature prediction, a simple model shows that the temperature is related to the Joule heating parameter, autothermal Joule heating parameter, external cooling parameter, Peclet number, and the channel length to channel hydraulic diameter ratio. The simple model overpredicted the thermally developed temperature compared with the full numerical simulation, but in good agreement with the experimental measurements. The factors that affect the external cooling parameters, such as the heat transfer coefficient, channel configuration, and channel material are also examined based on this simple model. Based on the mass conservation, a simple model is developed that predicts the pressure variations, including the temperature effect. An adverse pressure gradient is required to satisfy the mass conservation requirement. The temperature effect on the pressure gradient is via the temperature-dependent fluid viscosity and electroosmotic velocity. PMID:16380954

Chein, Reiyu; Yang, Yeong Chin; Lin, Yushan

2006-02-01

29

Measuring Joule heating and strain induced by electrical current with Moire interferometry  

SciTech Connect

This study proposes a new method to locate and measure the temperature of the hot spots caused by Joule Heating by measuring the free thermal expansion in-plane strain. It is demonstrated that the hotspot caused by the Joule heating in a thin metal film/plate structure can be measured by Phase shifting Moire interferometry with continuous wavelet transform (PSMI/CWT) at the microscopic scale. A demonstration on a copper film is conducted to verify the theory under different current densities. A correlation between the current density and strain in two orthogonal directions (one in the direction of the current flow) is proposed. The method can also be used for the measurement of the Joule heating in the microscopic solid structures in the electronic packaging devices. It is shown that a linear relationship exists between current density squared and normal strains.

Chen Bicheng; Basaran, Cemal [Electronic Packaging Laboratory, State University of New York at Buffalo, 102 Ketter Hall, Buffalo, New York 14260 (United States)

2011-04-01

30

Diffusion, Fluxes, Friction Forces, and Joule Heating in Two-Temperature Multicomponent Magnetohydrodynamics  

NASA Technical Reports Server (NTRS)

The relationship between Joule heating, diffusion fluxes, and friction forces has been studied for both total and electron thermal energy equations, using general expressions for multicomponent diffusion in two-temperature plasmas with the velocity dependent Lorentz force acting on charged species in a magnetic field. It is shown that the derivation of Joule heating terms requires both diffusion fluxes and friction between species which represents the resistance experienced by the species moving at different relative velocities. It is also shown that the familiar Joule heating term in the electron thermal energy equation includes artificial effects produced by switching the convective velocity from the species velocity to the mass-weighted velocity, and thus should not be ignored even when there is no net energy dissipation.

Chang, C. H.

1999-01-01

31

Effect of Joule heating on isoelectric focusing of proteins in a microchannel.  

PubMed

Electric field-driven separation and purification techniques, such as isoelectric focusing (IEF) and isotachophoresis, generate heat in the system that can affect the performance of the separation process. In this study, a new mathematical model is presented for IEF that considers the temperature rise due to Joule heating. We used the model to study focusing phenomena and separation performance in a microchannel. A finite volume-based numerical technique is developed to study temperature-dependent IEF. Numerical simulation for narrow range IEF (6?Joule heating in the system for a nominal electric field of 100?V/cm. For the no Joule heating case, constant properties are used, while for the Joule heating case, temperature-dependent titration curves and thermo-physical properties are used. Our numerical results show that the temperature change due to Joule heating has a significant impact on the final focusing points of proteins, which can lower the separation performance considerably. In the absence of advection and any active cooling mechanism, the temperature increase is the highest at the mid-section of a microchannel. We also found that the maximum temperature in the system is a strong function of the [Formula: see text] value of the carrier ampholytes. Simulation results are also obtained for different values of applied electric fields in order to find the optimum working range considering the simulation time and buffer temperature. Moreover, the model is extended to study IEF in a straight microchip where pH is formed by supplying H(+) and OH(-), and the thermal analysis shows that the heat generation is negligible in ion supplied IEF. PMID:25553199

Yoo, Kisoo; Shim, Jaesool; Dutta, Prashanta

2014-11-01

32

Joule-heating power dissipation in a type-II superconductor tube.  

NASA Technical Reports Server (NTRS)

The theoretical analysis of the Joule-heating power density in a specific hollow cylinder of a NbZr superconductor is presented. It is seen that the power density, which is the primary source of internal heating neglecting localized annihilation heating, can have a very complicated behavior, especially in the circular region. Rough estimates of the relative temperature changes are made, and the locations at which instabilities are more likely to initiate are considered.

Urban, E. W.

1972-01-01

33

A JOULE-HEATED MELTER TECHNOLOGY FOR THE TREATMENT AND IMMOBILIZATION OF LOW-ACTIVITY WASTE  

SciTech Connect

This report is one of four reports written to provide background information regarding immobilization technologies remaining under consideration for supplemental immobilization of Hanford's low-activity waste. This paper provides the reader a general understanding of joule-heated ceramic lined melters and their application to Hanford's low-activity waste.

KELLY SE

2011-04-07

34

Joule-heated glass furnace processing of a highly aqueous hazardous waste stream  

Microsoft Academic Search

A hazardous waste stream, covered by the Resource Conservation and Recovery Act (RCRA), generated as a by-product of explosives fabrication processes, was treated by means of a joule-heated glass furnace in a series of test burns at Mound. The burns were designed to determine the furnace's capability to meet the Environmental Protection Agency's hazardous waste incineration standard while processing a

L. M. Klinger; P. L. Abellera

1989-01-01

35

Local temperature redistribution and structural transition during joule-heating-driven conductance switching in VO2.  

PubMed

Joule-heating induced conductance-switching is studied in VO2 , a Mott insulator. Complementary in situ techniques including optical characterization, blackbody microscopy, scanning transmission X-ray microscopy (STXM) and numerical simulations are used. Abrupt redistribution in local temperature is shown to occur upon conductance-switching along with a structural phase transition, at the same current. PMID:23868142

Kumar, Suhas; Pickett, Matthew D; Strachan, John Paul; Gibson, Gary; Nishi, Yoshio; Williams, R Stanley

2013-11-13

36

Joule heat generation in thermionic cathodes of high-pressure arc discharges  

SciTech Connect

The nonlinear surface heating model of plasma-cathode interaction in high-pressure arcs is extended to take into account the Joule effect inside the cathode body. Calculation results are given for different modes of current transfer to tungsten cathodes of different configurations in argon plasmas of atmospheric or higher pressures. Special attention is paid to analysis of energy balances of the cathode and the near-cathode plasma layer. In all the cases, the variation of potential inside the cathode is much smaller than the near-cathode voltage drop. However, this variation can be comparable to the volt equivalent of the energy flux from the plasma to the cathode and then the Joule effect is essential. Such is the case of the diffuse and mixed modes on rod cathodes at high currents, where the Joule heating causes a dramatic change of thermal and electrical regimes of the cathode. The Joule heating has virtually no effect over characteristics of spots on rod and infinite planar cathodes.

Benilov, M. S.; Cunha, M. D. [Departamento de Fisica, CCCEE, Universidade da Madeira, Largo do Municipio, 9000 Funchal (Portugal)

2013-02-14

37

Asymptotic solution of natural convection in a uniformly Joule-heating shallow cavity  

NASA Astrophysics Data System (ADS)

The steady laminar two-dimensional Joule heating natural convection is investigated using asymptotical analysis, the fluid is in a rectangular cavity, the direct current contributes heat for heating the process medium by a pair of plate electrodes, the top wall is cooled with atmosphere and all the other walls are kept thermally insulated. The asymptotic solution is obtained in the core region in the limit as the aspect ratio, which is defined as the ratio of the vertical dimension of cavity to the horizontal dimension of cavity, goes to zero. The numerical experiments are also carried out to compare with the asymptotic solution of the steady twodimensional Joule heating convection. The asymptotic results indicate that the expressions of velocity and temperature fields in the core region are valid in the limit of the small aspect ratio.

Zhang, Xiaohui; Kadhim Hussin, Ahmed

2015-01-01

38

The equivalence of Joule dissipation and frictional heating in the collisional ionosphere  

NASA Astrophysics Data System (ADS)

We address what is meant by Joule dissipation in the context of the coupled magnetosphere-ionosphere-thermosphere system. We first show that the ionospheric Ohm's law that includes the classical Pedersen and Hall conductivities can be extended to include other terms such as plasma inertia and pressure. Within the ionosphere the Pedersen and Hall conductivities usually dominate. We note, however, that this does not mean that the electric field causes the currents. We next investigate the role of friction in heating the different species within the plasma. The frictional electron-ion collisional heating rate is proportional to j2, where j is the current density, and as such could be considered to be Ohmic in nature. The heating from electron-neutral collisions can be recast to include a term that includes j2, but only part of the electron collisional heating is Ohmic in the sense that it depends on j2. We also show that the Joule dissipation in the neutral frame equals the total amount of frictional heating for all the fluids (electrons, ions, and neutrals) with additional terms to account for the rate at which work is done by pressure gradient forces, and the power used to accelerate the plasma. In general, these additional terms are small within the ionosphere, and most of the Joule dissipation in the neutral frame results in heating, mainly by initially increasing the ion fluid temperature relative to the neutrals, while the neutral atmosphere temperature increases with a much slower rate.

Strangeway, Robert J.

2012-02-01

39

Modeling Joule Heating Effect on Lunar O2 Generation via Electrolytic Reduction.  

NASA Technical Reports Server (NTRS)

Kennedy Space Center is leading research work on lunar O2 generation via electrolytic reduction of regolith; the metal oxide present in the regolith is dissociated in oxygen anions and metal cations leading to the generation of gaseous oxygen at the anode and liquid metal at the cathode. Electrical resistance of molten regolith is high, leading to heating of the melt when electrical current is applied between the electrodes (Joule heating). The authors have developed a 3D model using a rigorous approach for two coupled physics (thermal and electrical potential) to not only study the effect of Joule heating on temperature distribution throughout the molten regolith but also to evaluate and optimize the design of the electrolytic cells. This paper presents the results of the thermal analysis performed on the model and used to validate the design of the electrolytic cell.

Dominquez, Jesus; Poizeau, Sophie; Sibille, Laurent

2009-01-01

40

Breakdown of Richardson's Law in Electron Emission from Individual Self-Joule-Heated Carbon Nanotubes  

PubMed Central

Probing the validity of classical macroscopic physical laws at the nanoscale is important for nanoscience research. Herein, we report on experimental evidence that electron emission from individual hot carbon nanotubes (CNTs) heated by self-Joule-heating does not obey Richardson's law of thermionic emission. By using an in-situ multi-probe measurement technique, electron emission density (J) and temperature (T) of individual self-Joule-heated CNTs are simultaneously determined. Experimental ln(J/T2) ? 1/T plots are found to exhibit an upward bending feature deviating from the straight lines in Richardson plots, and the measured electron emission density is more than one order of magnitude higher than that predicted by Richardson's law. The breakdown of Richardson's law implies a much better electron emission performance of individual CNTs as compared to their macroscopic allotropes and clusters, and the need of new theoretical descriptions of electron emission from individual low-dimensional nanostructures. PMID:24869719

Wei, Xianlong; Wang, Sheng; Chen, Qing; Peng, Lianmao

2014-01-01

41

Micro-scale heat-exchangers for Joule-Thomson cooling.  

SciTech Connect

This project focused on developing a micro-scale counter flow heat exchangers for Joule-Thomson cooling with the potential for both chip and wafer scale integration. This project is differentiated from previous work by focusing on planar, thin film micromachining instead of bulk materials. A process will be developed for fabricating all the devices mentioned above, allowing for highly integrated micro heat exchangers. The use of thin film dielectrics provides thermal isolation, increasing efficiency of the coolers compared to designs based on bulk materials, and it will allow for wafer-scale fabrication and integration. The process is intended to implement a CFHX as part of a Joule-Thomson cooling system for applications with heat loads less than 1mW. This report presents simulation results and investigation of a fabrication process for such devices.

Gross, Andrew John

2014-01-01

42

Jupiter Thermospheric General Circulation Model (JTGCM): Global Structure and Dynamics Driven by Auroral and Joule Heating  

NASA Technical Reports Server (NTRS)

A growing multispectral database plus recent Galileo descent measurements are being used to construct a self-consistent picture of the Jupiter thermosphere/ionosphere system. The proper characterization of Jupiter s upper atmosphere, embedded ionosphere, and auroral features requires the examination of underlying processes, including the feedbacks of energetics, neutral-ion dynamics, composition, and magnetospheric coupling. A fully 3-D Jupiter Thermospheric General Circulation Model (JTGCM) has been developed and exercised to address global temperatures, three-component neutral winds, and neutral-ion species distributions. The domain of this JTGCM extends from 20-microbar (capturing hydrocarbon cooling) to 1.0 x 10(exp -4) nbar (including aurora/Joule heating processes). The resulting JTGCM has been fully spun-up and integrated for greater than or equal to40 Jupiter rotations. Results from three JTGCM cases incorporating moderate auroral heating, ion drag, and moderate to strong Joule heating processes are presented. The neutral horizontal winds at ionospheric heights vary from 0.5 km/s to 1.2 km/s, atomic hydrogen is transported equatorward, and auroral exospheric temperatures range from approx.1200-1300 K to above 3000 K, depending on the magnitude of Joule heating. The equatorial temperature profiles from the JTGCM are compared with the measured temperature structure from the Galileo AS1 data set. The best fit to the Galileo data implies that the major energy source for maintaining the equatorial temperatures is due to dynamical heating induced by the low-latitude convergence of the high-latitude-driven thermospheric circulation. Overall, the Jupiter thermosphere/ionosphere system is highly variable and is shown to be strongly dependent on magnetospheric coupling which regulates Joule heating.

Bougher, S. W.; J. Il. Waite, Jr.; Majeed, T.

2005-01-01

43

Joule heating in the mesosphere and thermosphere during the July 13, 1982, solar proton event  

NASA Technical Reports Server (NTRS)

The solar proton event of July 13, 1982 produced considerable ionization in the polar-cap mesosphere. Energetic solar proton fluxes were measured by the NOAA-6 satellite. The DE-2 satellite measured the low-energy electrons, the ion drift velocity, and other atmospheric and ionospheric properties during the event in the region of the measured maximum electric field (189 mV/m at 2215 UT near 60 deg N), a Joule heating rate of 1-3 K/day is calculated between 70 and 80 km, exceeding the heating due to ozone absorption at noon in the summer hemisphere in that altitude range. The Joule heating rate above 90 km greatly exceeded 20 K/day. The calculated height-integrated Joule heating rate above 100 km in the same region exceeded 400 ergs/sq cm sec, and DE-2 near 350 km measured neutral winds of nearly 1000 m/s and neutral gas temperatures of over 2000 K. The overall ionospheric structure calculated below the DE-2 satellite is described.

Roble, R. G.; Emery, B. A.; Garcia, R. R.; Killeen, T. L.; Hays, P. B.; Reid, G. C.; Solomon, S.; Evans, D. S.; Spencer, N. W.; Brace, L. H.

1987-01-01

44

Incorporating Cold Cap Behavior in a Joule-heated Waste Glass Melter Model  

SciTech Connect

In this paper, an overview of Joule-heated waste glass melters used in the vitrification of high level waste (HLW) is presented, with a focus on the cold cap region. This region, in which feed-to-glass conversion reactions occur, is critical in determining the melting properties of any given glass melter. An existing 1D computer model of the cold cap, implemented in MATLAB, is described in detail. This model is a standalone model that calculates cold cap properties based on boundary conditions at the top and bottom of the cold cap. Efforts to couple this cold cap model with a 3D STAR-CCM+ model of a Joule-heated melter are then described. The coupling is being implemented in ModelCenter, a software integration tool. The ultimate goal of this model is to guide the specification of melter parameters that optimize glass quality and production rate.

Varija Agarwal; Donna Post Guillen

2013-08-01

45

Joule heating effects on particle immobilization in insulator-based dielectrophoretic devices  

PubMed Central

In this work, the temperature effects due to Joule heating obtained by application of a DC electric potential were investigated for a microchannel with cylindrical insulating posts employed for insulator based dielectrophoresis (iDEP). The conductivity of the suspending medium, the local electric field, and the gradient of the squared electric field, which directly affect the magnitude of the dielectrophoretic force exerted on particles, were computationally simulated employing COMSOL Multiphysics. It was observed that a temperature gradient is formed along the microchannel which redistributes the conductivity of the suspending medium leading to an increase of the dielectrophoretic force towards the inlet of the channel while decreasing towards the outlet. Experimental results are in good agreement with simulations on the particle trapping zones anticipated. This study demonstrates the importance of considering Joule heating effects when designing iDEP systems. PMID:24002905

Gallo-Villanueva, Roberto C.; Sano, Michael B.; Lapizco-Encinas, Blanca H.; Davalos, Rafael V.

2014-01-01

46

Joule heating effects on particle immobilization in insulator-based dielectrophoretic devices.  

PubMed

In this work, the temperature effects due to Joule heating obtained by application of a direct current electric potential were investigated for a microchannel with cylindrical insulating posts employed for insulator-based dielectrophoresis. The conductivity of the suspending medium, the local electric field, and the gradient of the squared electric field, which directly affect the magnitude of the dielectrophoretic force exerted on particles, were computationally simulated employing COMSOL Multiphysics. It was observed that a temperature gradient is formed along the microchannel, which redistributes the conductivity of the suspending medium leading to an increase of the dielectrophoretic force toward the inlet of the channel while decreasing toward the outlet. Experimental results are in good agreement with simulations on the particle-trapping zones anticipated. This study demonstrates the importance of considering Joule heating effects when designing insulator-based dielectrophoresis systems. PMID:24002905

Gallo-Villanueva, Roberto C; Sano, Michael B; Lapizco-Encinas, Blanca H; Davalos, Rafael V

2014-02-01

47

The role of Joule heating in dispersive mixing effects in electrophoretic cells: hydrodynamic considerations.  

PubMed

The analysis described in this contribution is focused on the effect of Joule heating generation on the hydrodynamics of batch electrophoretic cells (i.e., cells that do not display a forced convective term in the motion equation). The hydrodynamics of these cells is controlled by the viscous forces and by the buoyancy force caused by the temperature gradients due to the Joule heating generation. The analysis is based on differential models that lead to analytical and/or asymptotic solutions for the temperature and velocity profiles of the cell. The results are useful in determining the characteristics of the temperature and velocity profiles inside the cell. Furthermore, the results are excellent tools to be used in the analysis of the dispersive-mixing of solute when Joule heating generation must be accounted for. The analysis is performed by identifying two sequentially coupled problems. Thus, the "carrier fluid problem" and the "solute problem" are outlined. The former is associated with all the factors affecting the velocity profile and the latter is related to the convective-diffusion aspects that control the spreading of the solute inside the cell. The analysis of this contribution is centered on the discussion of the "carrier fluid problem" only. For the boundary conditions selected in the contribution, the study leads to the derivation of an analytical temperature and a "universal" velocity profile that feature the Joule heating number. The Grashof number is a scaling factor of the actual velocity profile. Several characteristics of these profiles are studied and some numerical illustrations have been included. PMID:10768789

Bosse, M A; Arce, P

2000-03-01

48

Programmable mechanical resonances in MEMS by localized joule heating of phase change materials.  

PubMed

A programmable micromechanical resonator based on a VO2 thin film is reported. Multiple mechanical eigenfrequency states are programmed using Joule heating as local power source, gradually driving the phase transition of VO2 around its Metal-Insulator transition temperature. Phase coexistence of domains is used to tune the stiffness of the device via local control of internal stresses and mechanical properties. This study opens perspectives for developing mechanically configurable nanostructure arrays. PMID:24038351

Manca, Nicola; Pellegrino, Luca; Kanki, Teruo; Yamasaki, Syouta; Tanaka, Hidekazu; Siri, Antonio Sergio; Marré, Daniele

2013-11-26

49

In situ transmission electron microscopy of individual carbon nanotetrahedron/nanoribbon structures in Joule heating  

SciTech Connect

Collapse of a carbon nanotube results in the formation of a nanoribbon, and a switching of the collapse direction yields a nanotetrahedron in the middle of a nanoribbon. Here, we report in-situ transmission electron microscopy observations of the behavior of carbon nanotetrahedron/nanoribbon structures during Joule heating to reveal their thermal stability. In addition, we propose that the observed process is related to the formation process of the structure.

Masuda, Yusuke [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Yoshida, Hideto; Takeda, Seiji [The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Kohno, Hideo, E-mail: kohno.hideo@kochi-tech.ac.jp [School of Environmental Science and Engineering, Kochi University of Technology, Kami, Kochi 782-8502 (Japan)

2014-08-25

50

Effect of Joule-heating annealing conditions on giant magnetoimpedance of Co-rich amorphous ribbons  

Microsoft Academic Search

Co-rich, soft magnetic amorphous ribbons, with composition Co68.25Fe4.5Si12.25B15 were prepared using a single roller melt-spinning technique. The effect of ac and dc Joule-heating annealing conditions on the GMI of these ribbons was investigated extensively. It was found that not only the current strength and annealing time, but also the cooling conditions, the geometry of the samples and the waveform of

Xuezhi Zhou; Guohua Tu; Henry Kunkel; Gwyn Williams

2006-01-01

51

Literature review of arc/plasma, combustion, and joule-heated melter vitrification systems  

SciTech Connect

This report provides reviews of papers and reports for three basic categories of melters: arc/plasma-heated melters, combustion-heated melters, and joule-heated melters. The literature reviewed here represents those publications which may lend insight to phase I testing of low-level waste vitrification being performed at the Hanford Site in FY 1995. For each melter category, information from those papers and reports containing enough information to determine steady-state mass balance data is tabulated at the end of each section. The tables show the composition of the feed processed, the off-gas measured via decontamination factors, gross energy consumptions, and processing rates, among other data.

Freeman, C.J.; Abrigo, G.P.; Shafer, P.J.; Merrill, R.A.

1995-07-01

52

Improved Ionospheric Electrodynamic Models and Application to Calculating Joule Heating Rates  

NASA Technical Reports Server (NTRS)

Improved techniques have been developed for empirical modeling of the high-latitude electric potentials and magnetic field aligned currents (FAC) as a function of the solar wind parameters. The FAC model is constructed using scalar magnetic Euler potentials, and functions as a twin to the electric potential model. The improved models have more accurate field values as well as more accurate boundary locations. Non-linear saturation effects in the solar wind-magnetosphere coupling are also better reproduced. The models are constructed using a hybrid technique, which has spherical harmonic functions only within a small area at the pole. At lower latitudes the potentials are constructed from multiple Fourier series functions of longitude, at discrete latitudinal steps. It is shown that the two models can be used together in order to calculate the total Poynting flux and Joule heating in the ionosphere. An additional model of the ionospheric conductivity is not required in order to obtain the ionospheric currents and Joule heating, as the conductivity variations as a function of the solar inclination are implicitly contained within the FAC model's data. The models outputs are shown for various input conditions, as well as compared with satellite measurements. The calculations of the total Joule heating are compared with results obtained by the inversion of ground-based magnetometer measurements. Like their predecessors, these empirical models should continue to be a useful research and forecast tools.

Weimer, D. R.

2004-01-01

53

Rapid response of the thermosphere to variations in Joule heating  

NASA Astrophysics Data System (ADS)

Total mass density measurements from the CHAMP satellite near 400 km altitude are used to define the response time of the thermosphere to high-latitude heating sources. A series of three geomagnetic storms occurred during the period of 20-29 July 2004 each with unique characteristics of energy input, affording the opportunity to observe the response characteristics of the thermosphere. By studying these storms in such close vicinity to one another, the aliasing effects of satellite sampling and seasonal and solar cycle variations are mitigated. Differences between the daytime and nighttime density response at all latitudes are discussed in the context of the various mechanisms. Generally, response times are between 3 and 4 h at low latitudes while less than 2 h at midlatitudes to high latitudes. These time lags are significantly shorter than those conventionally used to drive many empirical models of the thermosphere. During the night, response times are less accurate because of the somewhat sporadic arrival of traveling atmospheric disturbances at different latitudes.

Sutton, E. K.; Forbes, J. M.; Knipp, D. J.

2009-04-01

54

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars  

NASA Technical Reports Server (NTRS)

The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

Sibille, Laurent; Dominques, Jesus A.

2012-01-01

55

A 3D reconstruction solution to ultrasound Joule heat density tomography based on acousto-electric effect: a simulation study  

NASA Astrophysics Data System (ADS)

A 3D reconstruction solution to ultrasound Joule heat density tomography based on acousto-electric effect by deconvolution is proposed for noninvasive imaging of biological tissue. Compared with ultrasound current source density imaging, ultrasound Joule heat density tomography doesn't require any priori knowledge of conductivity distribution and lead fields, so it can gain better imaging result, more adaptive to environment and with wider application scope. For a general 3D volume conductor with broadly distributed current density field, in the AE equation the ultrasound pressure can't simply be separated from the 3D integration, so it is not a common modulation and basebanding (heterodyning) method is no longer suitable to separate Joule heat density from the AE signals. In the proposed method the measurement signal is viewed as the output of Joule heat density convolving with ultrasound wave. As a result, the internal 3D Joule heat density can be reconstructed by means of Wiener deconvolution. A series of computer simulations set for breast cancer imaging applications, with consideration of ultrasound beam diameter, noise level, conductivity contrast, position dependency and size of simulated tumors, have been conducted to evaluate the feasibility and performance of the proposed reconstruction method. The computer simulation results demonstrate that high spatial resolution 3D ultrasound Joule heat density imaging is feasible using the proposed method, and it has potential applications to breast cancer detection and imaging of other organs.

Yang, R.; Song, A.; Li, X. D.; Lu, Y.; Yan, R.; Xu, B.; Li, X.

2014-10-01

56

Simple and strong: twisted silver painted nylon artificial muscle actuated by Joule heating  

NASA Astrophysics Data System (ADS)

Highly oriented nylon and polyethylene fibres shrink in length when heated and expand in diameter. By twisting and then coiling monofilaments of these materials to form helical springs, the anisotropic thermal expansion has recently been shown to enable tensile actuation of up to 49% upon heating. Joule heating, by passing a current through a conductive coating on the surface of the filament, is a convenient method of controlling actuation. In previously reported work this has been done using highly flexible carbon nanotube sheets or commercially available silver coated fibres. In this work silver paint is used as the Joule heating element at the surface of the muscle. Up to 29% linear actuation is observed with energy and power densities reaching 840 kJ m-3 (528 J kg-1) and 1.1 kW kg-1 (operating at 0.1 Hz, 4% strain, 1.4 kg load). This simple coating method is readily accessible and can be applied to any polymer filament. Effective use of this technique relies on uniform coating to avoid temperature gradients.

Mirvakili, Seyed M.; Rafie Ravandi, Ali; Hunter, Ian W.; Haines, Carter S.; Li, Na; Foroughi, Javad; Naficy, Sina; Spinks, Geoffrey M.; Baughman, Ray H.; Madden, John D. W.

2014-03-01

57

Impact of Magnetic Field on Mixed Convective Peristaltic Flow of Water Based Nanofluids with Joule Heating  

NASA Astrophysics Data System (ADS)

Peristaltic transport of water-based nanofluids in the presence of applied magnetic field is studied. Two different types of nanofluids (silver-water and copper-water nanofluids) are used in the analysis. Effects of mixed convection, viscous dissipation, Joule heating, and heat generation/absorption are considered. Long wavelength and low Reynolds number approximations are used in the mathematical modelling. Numerical solutions are obtained for the velocity, pressure gradient, pressure rise per wavelength, temperature, and heat transfer rate at the wall. Physical quantities of interest are studied through graphs and tables. Comparison of water, silver-water, and copper-water nanofluid is presented. Results show that velocity and temperature of ordinary water are larger than those of nanofluids. Maximum velocity, temperature, and heat transfer rate at the wall of silver-water nanofluid is relatively higher than the copper-water nanofluid.

Abbasi, Fahad Munir; Hayat, Tasawar; Ahmad, Bashir

2015-02-01

58

A Model of Solar Radiation and Joule Heating in Flow of Third Grade Nanofluid  

NASA Astrophysics Data System (ADS)

The flow problem resulting from the stretching of a surface with convective conditions in a magnetohydrodynamic nanofluid with solar radiation is examined. Both heat and nanoparticle mass transfer convective conditions are employed. An incompressible third grade fluid which exhibits shear thinning and shear thickening characteristics is used as a base fluid. Concept of convective nanoparticle mass condition is introduced. Effects of Brownian motion and thermophoresis on magnetohydrodynamic flow of nanofluid are accounted in the presence of thermal radiation. Energy equation incorporates the features of Joule heating. The impact of physical parameters on the temperature and nanoparticle concentration has been pointed out. Numerical values of skin-friction coefficient are presented and analysed. It is hoped that this present investigation serves as a stimulus for the next generation of solar film collectors, heat exchangers technology, material processing, geothermal energy storage, and all those processes which are highly affected by the heat enhancement concept.

Hussain, Tariq; Hayat, Tasawar; Shehzad, Sabir Ali; Alsaedi, Ahmed; Chen, Bin

2015-03-01

59

Solar wind effect on Joule heating in the high-latitude ionosphere  

NASA Astrophysics Data System (ADS)

The effect of solar wind on several electrodynamic parameters, measured simultaneously by the European Incoherent Scatter (EISCAT) radars in Tromsø (TRO, 66.6° cgmLat) and on Svalbard (ESR, 75.4° cgmLat), has been evaluated statistically. The main emphasis is on Joule heating rate QJ, which has been estimated by taking into account the neutral wind. In addition, a generally used proxy QE, which is the Pedersen conductance times the electric field squared, has been calculated. The most important findings are as follows. (i) The decrease in Joule heating in the afternoon-evening sector due to winds reported by Aikio et al. (2012) requires southward interplanetary magnetic field (IMF) conditions and a sufficiently high solar wind electric field. The increase in the morning sector takes place for all IMF directions within a region where the upper E neutral wind has a large equatorward component and the F region plasma flow is directed eastward. (ii) At ESR, an afternoon hot spot of Joule heating centered typically at 14-15 magnetic local time (MLT) is observed during all IMF conditions. Enhanced Pedersen conductances within the hot spot region are observed only for the IMF Bz + /By- conditions, and the corresponding convection electric field values within the hot spot are smaller than during the other IMF conditions. Hence, the hot spot represents a region of persistent magnetospheric electromagnetic energy input, and the median value is about 3 mW/m2. (iii) For the southward IMF conditions, the MLT-integrated QE for By- is twice the value for By+ at TRO. This can plausibly be explained by the higher average solar wind electric field values for By-.

Cai, L.; Aikio, A. T.; Nygrén, T.

2014-12-01

60

Remote Joule heating by a carbon nanotube Kamal H. Baloch1, Norvik Voskanian1, Merijntje Bronsgeest2 and John Cumings1  

E-print Network

is reminiscent of induction heating or microwave dielectric heating. Such an ability to dissipate waste energyRemote Joule heating by a carbon nanotube Kamal H. Baloch1, Norvik Voskanian1, Merijntje Bronsgeest2 and John Cumings1 * Minimizing Joule heating remains an important goal in the design of electronic

Li, Teng

61

Unsteady MHD three-dimensional flow with viscous dissipation and Joule heating  

NASA Astrophysics Data System (ADS)

This article addresses the viscous dissipation and Joule heating effects in unsteady magnetohydrodynamic (MHD) three-dimensional flow forced by an exponentially stretching surface. The momentum and thermal equations in the boundary layer regime are reduced into the ordinary differential equations using appropriate transformations. Computations for series solutions of velocity and temperature are first made and then analyzed with respect to influential parameters. Numerical values of skin friction coefficients and local Nusselt number are given and examined. The present results are also found to be in very good agreement with the existing aymptotic solutions.

Hayat, T.; Naseem, Anum; Farooq, M.; Alsaedi, A.

2013-12-01

62

Joule heating and thermoelectric properties in short single-walled carbon nanotubes: Electron-phonon interaction effect  

NASA Astrophysics Data System (ADS)

The electron-phonon interaction (EPI) effect in single-walled carbon nanotube is investigated by the nonequilibrium Green's function approach within the Born approximation. Special attention is paid to the EPI induced Joule heating phenomenon and the thermoelectric properties in both metallic armchair (10, 10) tube and semiconductor zigzag (10, 0) tube. For Joule heat in the metallic (10, 10) tube, the theoretical results for the breakdown bias voltage is quite comparable with the experimental value. It is found that the Joule heat can be greatly enhanced by increasing the chemical potential, while the role of the temperature is not so important for Joule heat. In the zigzag (10, 0) tube, the Joule heat is smaller than the armchair tube, resulting from nonzero bandgap in the electron band structure. For the electronic conductance Ge and electron thermal conductance ?el, the EPI has important effect at higher temperature or higher chemical potential. Compared with ballistic transport, there is an opposite tendency for Ge to decrease with increasing temperature after EPI is considered. This is due to the dominant effect of the electron phonon scattering mechanism in the electron transport in this situation. There is an interesting "electron-drag" phenomenon for the phonon thermal conductance in case of low temperature and high chemical potential, where phonons are dragged by electrons from low temperature region into high temperature region through EPI effect.

Jiang, Jin-Wu; Wang, Jian-Sheng

2011-12-01

63

3D noninvasive ultrasound Joule heat tomography based on acousto-electric effect using unipolar pulses: a simulation study  

PubMed Central

Electrical properties of biological tissues are highly sensitive to their physiological and pathological status. Thus it is of importance to image electrical properties of biological tissues. However, spatial resolution of conventional electrical impedance tomography (EIT) is generally poor. Recently, hybrid imaging modalities combining electric conductivity contrast and ultrasonic resolution based on acouto-electric effect has attracted considerable attention. In this study, we propose a novel three-dimensional (3D) noninvasive ultrasound Joule heat tomography (UJHT) approach based on acouto-electric effect using unipolar ultrasound pulses. As the Joule heat density distribution is highly dependent on the conductivity distribution, an accurate and high resolution mapping of the Joule heat density distribution is expected to give important information that is closely related to the conductivity contrast. The advantages of the proposed ultrasound Joule heat tomography using unipolar pulses include its simple inverse solution, better performance than UJHT using common bipolar pulses and its independence of any priori knowledge of the conductivity distribution of the imaging object. Computer simulation results show that using the proposed method, it is feasible to perform a high spatial resolution Joule heat imaging in an inhomogeneous conductive media. Application of this technique on tumor scanning is also investigated by a series of computer simulations. PMID:23123757

Yang, Renhuan; Li, Xu; Song, Aiguo; He, Bin; Yan, Ruqiang

2012-01-01

64

Polycrystalline silicon thin-film transistors fabricated by Joule-heating-induced crystallization  

NASA Astrophysics Data System (ADS)

Joule-heating-induced crystallization (JIC) of amorphous silicon (a-Si) films is carried out by applying an electric pulse to a conductive layer located beneath or above the films. Crystallization occurs across the whole substrate surface within few tens of microseconds. Arc instability, however, is observed during crystallization, and is attributed to dielectric breakdown in the conductor/insulator/transformed polycrystalline silicon (poly-Si) sandwich structures at high temperatures during electrical pulsing for crystallization. In this study, we devised a method for the crystallization of a-Si films while preventing arc generation; this method consisted of pre-patterning an a-Si active layer into islands and then depositing a gate oxide and gate electrode. Electric pulsing was then applied to the gate electrode formed using a Mo layer. The Mo layer was used as a Joule-heat source for the crystallization of pre-patterned active islands of a-Si films. JIC-processed poly-Si thin-film transistors (TFTs) were fabricated successfully, and the proposed method was found to be compatible with the standard processing of coplanar top-gate poly-Si TFTs.

Hong, Won-Eui; Ro, Jae-Sang

2015-01-01

65

Impact of Joule heating on the microstructure of nanoscale TiO2 resistive switching devices  

NASA Astrophysics Data System (ADS)

The microstructure of TiO2 functional layers in nanoscale resistive switching devices was analyzed using Scanning Electron and Transmission Electron Microscopies (SEM and TEM). The TiO2 layers in as-fabricated devices were amorphous with very weak lattice fringes in High Resolution TEM. After electroformation with low power dissipation (PDIS < 0.4 mW), the microstructural changes in the TiO2 layer were limited to an area approximately 75˜100 nm in radius indicating that the current path and Joule heating were localized. Since the reset power (?2.4 mW) was greater than the electroformation power, switching cycles resulted in an increased area of the TiO2 affected zone and more morphological changes to the Pt electrodes and functional layers. Electroformation under large power dissipation (15 mW) led to massive redistribution of Pt, including shorting of electrodes through the oxide layer. Modeling temperature distribution in the devices found maximum temperature to be strongly dependent on the power dissipation. Computational estimates of the temperature exceed 323 °C at electroformation (0.4 mW), 819 °C at reset (2.4 mW), and the melting point of Pt electrode at large power (15 mW) dissipation. The microstructural changes appear to be caused by Joule heating during device operation.

Meng Lu, Yi; Noman, Mohammad; Picard, Yoosuf N.; Bain, James A.; Salvador, Paul A.; Skowronski, Marek

2013-04-01

66

Nanoscale Joule heating and electromigration enhanced ripening of silver nanowire contacts.  

PubMed

Solution-processed metallic nanowire thin film is a promising candidate to replace traditional indium tin oxide as the next-generation transparent and flexible electrode. To date however, the performance of these electrodes is limited by the high contact resistance between contacting nanowires; so improving the point contacts between these nanowires remains a major challenge. Existing methods for reducing the contact resistance require either a high processing power, long treatment time, or the addition of chemical reagents, which could lead to increased manufacturing cost and damage the underlying substrate or device. Here, a nanoscale point reaction process is introduced as a fast and low-power-consumption way to improve the electrical contact properties between metallic nanowires. This is achieved via current-assisted localized joule heating accompanied by electromigration. Localized joule heating effectively targets the high-resistance contact points between nanowires, leading to the automatic removal of surface ligands, welding of contacting nanowires, and the reshaping of the contact pathway between the nanowires to form a more desirable geometry of low resistance for interwire conduction. This result shows the interplay between thermal and electrical interactions at the highly reactive nanocontacts and highlights the control of the nanoscale reaction as a simple and effective way of turning individual metallic nanowires into a highly conductive interconnected nanowire network. The temperature of the adjacent device layers can be kept close to room temperature during the process, making this method especially suitable for use in devices containing thermally sensitive materials such as polymer solar cells. PMID:24517263

Song, Tze-Bin; Chen, Yu; Chung, Choong-Heui; Yang, Yang Michael; Bob, Brion; Duan, Hsin-Sheng; Li, Gang; Tu, King-Ning; Huang, Yu; Yang, Yang

2014-03-25

67

Electron kinetics and non-Joule heating in near-collisionless inductively coupled plasmas V. I. Kolobov  

E-print Network

Electron kinetics and non-Joule heating in near-collisionless inductively coupled plasmas V. I of Houston, Houston, Texas 77204-4792 Received 1 July 1996 Electron kinetics in an inductively coupled plasma magnetic field induced by the coil current and the finite dimension of the plasma on electron heating

Economou, Demetre J.

68

MHD Mixed Convective Peristaltic Motion of Nanofluid with Joule Heating and Thermophoresis Effects  

PubMed Central

The primary objective of present investigation is to introduce the novel aspect of thermophoresis in the mixed convective peristaltic transport of viscous nanofluid. Viscous dissipation and Joule heating are also taken into account. Problem is modeled using the lubrication approach. Resulting system of equations is solved numerically. Effects of sundry parameters on the velocity, temperature, concentration of nanoparticles and heat and mass transfer rates at the wall are studied through graphs. It is noted that the concentration of nanoparticles near the boundaries is enhanced for larger thermophoresis parameter. However reverse situation is observed for an increase in the value of Brownian motion parameter. Further, the mass transfer rate at the wall significantly decreases when Brownian motion parameter is assigned higher values. PMID:25391147

Shehzad, Sabir Ali; Abbasi, Fahad Munir; Hayat, Tasawar; Alsaadi, Fuad

2014-01-01

69

MHD mixed convective peristaltic motion of nanofluid with Joule heating and thermophoresis effects.  

PubMed

The primary objective of present investigation is to introduce the novel aspect of thermophoresis in the mixed convective peristaltic transport of viscous nanofluid. Viscous dissipation and Joule heating are also taken into account. Problem is modeled using the lubrication approach. Resulting system of equations is solved numerically. Effects of sundry parameters on the velocity, temperature, concentration of nanoparticles and heat and mass transfer rates at the wall are studied through graphs. It is noted that the concentration of nanoparticles near the boundaries is enhanced for larger thermophoresis parameter. However reverse situation is observed for an increase in the value of Brownian motion parameter. Further, the mass transfer rate at the wall significantly decreases when Brownian motion parameter is assigned higher values. PMID:25391147

Shehzad, Sabir Ali; Abbasi, Fahad Munir; Hayat, Tasawar; Alsaadi, Fuad

2014-01-01

70

Nanoscale Joule heating, Peltier cooling and current crowding at graphene-metal contacts.  

PubMed

The performance and scaling of graphene-based electronics is limited by the quality of contacts between the graphene and metal electrodes. However, the nature of graphene-metal contacts remains incompletely understood. Here, we use atomic force microscopy to measure the temperature distributions at the contacts of working graphene transistors with a spatial resolution of ~ 10 nm (refs 5-8), allowing us to identify the presence of Joule heating, current crowding and thermoelectric heating and cooling. Comparison with simulation enables extraction of the contact resistivity (150-200 ? µm²) and transfer length (0.2-0.5 µm) in our devices; these generally limit performance and must be minimized. Our data indicate that thermoelectric effects account for up to one-third of the contact temperature changes, and that current crowding accounts for most of the remainder. Modelling predicts that the role of current crowding will diminish and the role of thermoelectric effects will increase as contacts improve. PMID:21460825

Grosse, Kyle L; Bae, Myung-Ho; Lian, Feifei; Pop, Eric; King, William P

2011-05-01

71

Tailored Electrical Driving as a Means of Controlling Heat Distribution and Convection Patterns in Joule-Heated Waste Glass Melters  

SciTech Connect

The ability to control melter convection patterns may provide a means of mitigating gas layer buildup under the cold cap, enhancing the heat transfer to the batch, and possible accelerating batch reactions, thereby increasing melt rate and glass throughput. Other operational benefits could result from such control. Convective patterns in an electrically heated melter are dominated by the distribution of Joule heat and thermal boundary conditions for a given melter design and geometry. We believe that control of electrical driving, in particular control of the interaction of electrical fields connected to distinct electrode pairs, can be used to vary the distribution of Joule heat generation. The under-investigated aspect of electrical driving control is the effect of waveform “overlap” of the driving voltages, the “overlap” in the case of harmonic driving being determined by the relative phase. For electrical driving using waveforms chopped by Silicon Controlled Rectifiers (SCRs), the chopping influences the "overlap." This control can provide a means of controlling melt convection. The objective of the present investigation is to test that hypothesis, verifying that such control can be observed for a numerical model of a simple melter geometry.

Fort, James A.; Lessor, Delbert L.

2004-01-01

72

Residual resistance of 2D and 3D structures and Joule heat release.  

PubMed

We consider a residual resistance and Joule heat release in 2D nanostructures as well as in ordinary 3D conductors. We assume that elastic scattering of conduction electrons by lattice defects is predominant. Within a rather intricate situation in such systems we discuss in detail two cases. (1) The elastic scattering alone (i.e. without regard of inelastic mechanisms of scattering) leads to a transition of the mechanical energy (stored by the electrons under the action of an electric field) into heat in a traditional way. This process can be described by the Boltzmann equation where it is possible to do the configuration averaging over defect positions in the electron-impurity collision term. The corresponding conditions are usually met in metals. (2) The elastic scattering can be considered with the help of the standard electron-impurity collision integral only in combination with some additional averaging procedure (possibly including inelastic scattering or some mechanisms of electron wavefunction phase destruction). This situation is typical for degenerate semiconductors with a high concentration of dopants and conduction electrons. Quite often, heat release can be observed via transfer of heat to the lattice, i.e. via inelastic processes of electron-phonon collisions and can take place at distances much larger than the size of the device. However, a direct heating of the electron system can be registered too by, for instance, local measurements of the current noise or direct measurement of an electron distribution function. PMID:21628783

Gurevich, V L; Kozub, V I

2011-06-22

73

Residual resistance of 2D and 3D structures and Joule heat release  

NASA Astrophysics Data System (ADS)

We consider a residual resistance and Joule heat release in 2D nanostructures as well as in ordinary 3D conductors. We assume that elastic scattering of conduction electrons by lattice defects is predominant. Within a rather intricate situation in such systems we discuss in detail two cases. (1) The elastic scattering alone (i.e. without regard of inelastic mechanisms of scattering) leads to a transition of the mechanical energy (stored by the electrons under the action of an electric field) into heat in a traditional way. This process can be described by the Boltzmann equation where it is possible to do the configuration averaging over defect positions in the electron-impurity collision term. The corresponding conditions are usually met in metals. (2) The elastic scattering can be considered with the help of the standard electron-impurity collision integral only in combination with some additional averaging procedure (possibly including inelastic scattering or some mechanisms of electron wavefunction phase destruction). This situation is typical for degenerate semiconductors with a high concentration of dopants and conduction electrons. Quite often, heat release can be observed via transfer of heat to the lattice, i.e. via inelastic processes of electron-phonon collisions and can take place at distances much larger than the size of the device. However, a direct heating of the electron system can be registered too by, for instance, local measurements of the current noise or direct measurement of an electron distribution function.

Gurevich, V. L.; Kozub, V. I.

2011-06-01

74

On the relative importance of Joule heating and the Lorentz force in generating atmospheric gravity waves and infrasound waves in the auroral electrojets  

Microsoft Academic Search

An analysis of the relative importance of the contribution from the Lorentz force and the Joule heating rate as source for the TIDs reveals that a strong height dependence must be expected. Also it is found that for horizontal electric fields larger than about 40 mV\\/m the Joule heating rate will be most dominant above 110 km.

A. Brekke

1979-01-01

75

Current-Controlled Negative Differential Resistance Due to Joule Heating In Tio2  

NASA Astrophysics Data System (ADS)

We show that Joule heating causes current-controlled negative differential resistance (CC-NDR) in TiO2 memristive systems by constructing an analytical model of the current-voltage characteristics based on polaronic transport for Ohm's law and Newton's law of cooling and fitting this model to experimental data. This threshold switching is he ``soft breakdown'' observed during electroforming in TiO2 and other transition-metal oxide based memristors, as well as a precursor to ``ON'' or ``SET'' switching of unipolar memristors from their high to their low resistance states. The shape of the V-I curves is a sensitive indicator of the nature of the polaronic conduction, which apparently follows an adiabatic regime [1]. [4pt] [1] A.S. Alexandrov, A.M.Bratkovsky, B.Bridle, S.E.Savel'ev, D. Strukov, and R.S.Williams, Appl. Phys. Lett. 99, xxx (2011).

Bratkovsky, A. M.; Alexandrov, A. S.; Savel'Ev, S. E.; Strukov, D. B.; Williams, R. S.

2012-02-01

76

Current-controlled negative differential resistance due to Joule heating in TiO2  

NASA Astrophysics Data System (ADS)

We show that Joule heating causes current-controlled negative differential resistance (CC-NDR) in TiO2 by constructing an analytical model of the voltage-current V(I) characteristic based on polaronic transport for Ohm's Law and Newton's Law of Cooling and fitting this model to experimental data. This threshold switching is the "soft breakdown" observed during electroforming of TiO2 and other transition-metal-oxide based memristors, as well as a precursor to "ON" or "SET" switching of unipolar memristors from their high to their low resistance states. The shape of the V(I) curve is a sensitive indicator of the nature of the polaronic conduction.

Alexandrov, A. S.; Bratkovsky, A. M.; Bridle, B.; Savel'ev, S. E.; Strukov, D. B.; Stanley Williams, R.

2011-11-01

77

Current-Controlled Negative Differential Resistance due to Joule Heating in TiO2  

E-print Network

We show that Joule heating causes current-controlled negative differential resistance (CC-NDR) in TiO2 by constructing an analytical model of the voltage-current V(I) characteristic based on polaronic transport for Ohm's Law and Newton's Law of Cooling, and fitting this model to experimental data. This threshold switching is the 'soft breakdown' observed during electroforming of TiO2 and other transition-metal-oxide based memristors, as well as a precursor to 'ON' or 'SET' switching of unipolar memristors from their high to their low resistance states. The shape of the V(I) curve is a sensitive indicator of the nature of the polaronic conduction.

A. S. Alexandrov; A. M. Bratkovsky; B. Bridle; S. E. Savel'ev; D. B. Strukov; R. Stanley Williams

2011-08-15

78

Using an empirical model of Joule heating in thermosphere-ionosphere coupled models  

NASA Astrophysics Data System (ADS)

The interaction of the solar wind and the embedded Interplanetary Magnetic Field (IMF) with the Earth's magnetic field produces auroral currents that heat the ionosphere at high-latitudes. Coupling between the ionosphere and thermosphere results in significant heating of the ther-mosphere. During major geomagnetic storms the temperature changes in the thermosphere are significant, causing the neutral atmosphere to expand upward, which in turn causes satellites in low-Earth orbit to experience a higher drag force and decreased orbital velocity. There is a real need to model and predict these variations in the thermosphere. The Weimer 2005 model of ionospheric electric potentials and field-aligned currents can be used to help solve this problem. This presentation will describe the model and how it derives the ionospheric Joule heating rates. Comparisons with neutral density derived from CHAMP and GRACE satellite measurements will also be shown. This comparison is facilitated through use of the "global nighttime minimum exospheric temperature" (Tc) in the Jacchia-Bowman 2008 (JB2008) model. It is shown that the empirical model of auroral heating can be used to quite accurately predict orbit-averaged perturbations to Tc as a function of time, given measurements of the IMF. The empirical model can also be used as a driver in physics-based, numerical Thermosphere-Ionosphere Coupled Models; present and future uses in such programs will be covered.

Weimer, Daniel

79

Influence of Newtonian Heating on Three Dimensional MHD Flow of Couple Stress Nanofluid with Viscous Dissipation and Joule Heating  

PubMed Central

The present exploration discusses the influence of Newtonian heating on the magnetohydrodynamic (MHD) three dimensional couple stress nanofluid past a stretching surface. Viscous dissipation and Joule heating effects are also considered. Moreover, the nanofluid model includes the combined effects of thermophoresis and Brownian motion. Using an appropriate transformation, the governing non linear partial differential equations are converted into nonlinear ordinary differential equations. Series solutions using Homotopy Analysis method (HAM) are computed. Plots are presented to portrait the arising parameters in the problem. It is seen that an increase in conjugate heating parameter results in considerable increase in the temperature profile of the stretching wall. Skin friction coefficient, local Nusselt and local Sherwood numbers tabulated and analyzed. Higher values of conjugate parameter, Thermophoresis parameter and Brownian motion parameter result in enhancement of temperature distribution. PMID:25874800

Ramzan, Muhammad

2015-01-01

80

Influence of Newtonian Heating on Three Dimensional MHD Flow of Couple Stress Nanofluid with Viscous Dissipation and Joule Heating.  

PubMed

The present exploration discusses the influence of Newtonian heating on the magnetohydrodynamic (MHD) three dimensional couple stress nanofluid past a stretching surface. Viscous dissipation and Joule heating effects are also considered. Moreover, the nanofluid model includes the combined effects of thermophoresis and Brownian motion. Using an appropriate transformation, the governing non linear partial differential equations are converted into nonlinear ordinary differential equations. Series solutions using Homotopy Analysis method (HAM) are computed. Plots are presented to portrait the arising parameters in the problem. It is seen that an increase in conjugate heating parameter results in considerable increase in the temperature profile of the stretching wall. Skin friction coefficient, local Nusselt and local Sherwood numbers tabulated and analyzed. Higher values of conjugate parameter, Thermophoresis parameter and Brownian motion parameter result in enhancement of temperature distribution. PMID:25874800

Ramzan, Muhammad

2015-01-01

81

James Joule and meteors  

NASA Astrophysics Data System (ADS)

1989 was the hundredth anniversary of the death of James Prescott Joule, the Prescott being his mother's family name and the Joule, rhyming with cool, originating from the Derbyshire village of Youlgreave. Joule is rightly famous for his experimental efforts to establish the law of conservation of energy, and for the fact that J, the symbol known as the mechanical equivalent of heat, is named after him. Astronomically his "light has been hidden under a bushel". James Joule had a major influence on the physics of meteors.

Hughes, David W.

82

Transmission electron microscopy assisted in-situ joule heat dissipation study of individual InAs nanowires  

SciTech Connect

Managing heat transport at nanoscale is an important and challenging task for nanodevice applications and nanostructure engineering. Herein, through in-situ engineering nanowire (NW)-electrode contacts with electron beam induced carbon deposition in a transmission electron microscope, Joule heat dissipation along individual suspended Indium Arsenide NWs is well managed to obtain pre-designed temperature profiles along NWs. The temperature profiles are experimentally determined by the breakdown site of NWs under Joule heating and breakdown temperature measurement. A model with NW-electrode contacts being well considered is proposed to describe heat transport along a NW. By fitting temperature profiles with the model, thermal conductance at NW-electrode contacts is obtained. It is found that, the temperature profile along a specific NW is mainly governed by the relative thermal conductance at the two NW-electrode contacts, which is engineered in experiments.

Xu, T. T.; Wei, X. L., E-mail: weixl@pku.edu.cn, E-mail: qingchen@pku.edu.cn; Shu, J. P.; Chen, Q., E-mail: weixl@pku.edu.cn, E-mail: qingchen@pku.edu.cn [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China)

2013-11-04

83

Polar thermospheric Joule heating, and redistribution of recombination energy in the upper mesosphere  

NASA Technical Reports Server (NTRS)

Kellogg (1961), suggested that transport of atomic oxygen from the summer into the winter hemisphere and subsequent release of energy by three body recombination, O+O+N2 yields O2+N2+E, may contribute significantly to the so-called mesopause temperature anomaly. Earlier model calculations have shown that Kellogg's mechanism produces about a 10-percent increase in the temperature from summer to winter at 90 km. This process, however, is partly compensated by differential heating from absorption of UV radiation associated with dissociation of O2. In the auroral region of the thermosphere, there is a steady energy dissipation by Joule heating causing a redistribution and depletion of atomic oxygen due to wind-induced diffusion. With the removal of O, latent chemical energy normally released by three body recombination is also removed, and the result is that the temperature decreases by almost 2 percent near 90 km. Through dynamic feedback, this process reduces the depletion of atomic oxygen by about 25 percent and the temperature perturbation in the exosphere from 10 to 7 percent at polar latitudes. Under the influence of the internal dynamo interaction, the prevailing zonal circulation in the upper thermosphere changes direction when the redistribution of recombination energy is considered.

Mayr, H. G.; Harris, I.; Dube, M.

1990-01-01

84

Effect of concurrent joule heat and charge trapping on RESET for NbAlO fabricated by atomic layer deposition  

PubMed Central

The RESET process of NbAlO-based resistive switching memory devices fabricated by atomic layer deposition is investigated at low temperatures from 80 to 200 K. We observed that the conduction mechanism of high resistance state changed from hopping conduction to Frenkel-Poole conduction with elevated temperature. It is found that the conductive filament rupture in RRAM RESET process can be attributed not only to the Joule heat generated by internal current flow through a filament but also to the charge trap/detrapping effect. The RESET current decreases upon heating. Meanwhile, the energy consumption also decreases exponentially. This phenomenon indicates the temperature-related charge trap/detrapping process which contributes to the RESET besides direct Joule heat. PMID:23421401

2013-01-01

85

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars  

NASA Technical Reports Server (NTRS)

The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a Joule-heated (sometimes called 'self-heating') reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. Solutions obtained by multiphysics modeling allow the identification of the critical dimensions of concept reactors.

Sibille, Laurent; Dominguez, Jesus A.

2012-01-01

86

Consistent melting behavior induced by Joule heating between Ag microwire and nanowire meshes  

PubMed Central

The melting behavior of an Ag microwire mesh induced by Joule heating was numerically investigated and compared with that of the corresponding Ag nanowire mesh with the same structure but different geometrical and physical properties of the wire itself. According to the relationship of melting current and melting voltage during the melting process, a similar repetitive zigzag pattern in melting behavior was discovered in both meshes. On this basis, a dimensionless parameter defined as figure of merit was proposed to characterize the current-carrying ability of the mesh. The consistent feature of figure of merit in both meshes indicates that the melting behavior of the Ag nanowire mesh can be predicted from the present results of the corresponding Ag microwire mesh with the same structure but made from a different wire (e.g., different size, different material) through simple conversion. The present findings can provide fundamental insight into the reliability analysis on the metallic nanowire mesh-based transparent conductive electrode. PMID:24910578

2014-01-01

87

Rapid concentration of deoxyribonucleic acid via Joule heating induced temperature gradient focusing in poly-dimethylsiloxane microfluidic channel.  

PubMed

This paper reports rapid microfluidic electrokinetic concentration of deoxyribonucleic acid (DNA) with the Joule heating induced temperature gradient focusing (TGF) by using our proposed combined AC and DC electric field technique. A peak of 480-fold concentration enhancement of DNA sample is achieved within 40s in a simple poly-dimethylsiloxane (PDMS) microfluidic channel of a sudden expansion in cross-section. Compared to a sole DC field, the introduction of an AC field can reduce DC field induced back-pressure and produce sufficient Joule heating effects, resulting in higher concentration enhancement. Within such microfluidic channel structure, negative charged DNA analytes can be concentrated at a location where the DNA electrophoretic motion is balanced with the bulk flow driven by DC electroosmosis under an appropriate temperature gradient field. A numerical model accounting for a combined AC and DC field and back-pressure driven flow effects is developed to describe the complex Joule heating induced TGF processes. The experimental observation of DNA concentration phenomena can be explained by the numerical model. PMID:25597807

Ge, Zhengwei; Wang, Wei; Yang, Chun

2015-02-01

88

Unsteady MHD natural convection from a heated vertical porous plate in a micropolar fluid with Joule heating, chemical reaction and radiation effects  

Microsoft Academic Search

The effects of Joule-heating, chemical reaction and thermal radiation on unsteady MHD natural convection from a heated vertical\\u000a porous plate in a micropolar fluid are analyzed. The partial differential equations governing the flow and heat and mass transfer\\u000a have been solved numerically using an implicit finite-difference scheme. The case corresponding to vanishing of the anti-symmetric\\u000a part of the stress tensor

Ali J. Chamkha; R. A. Mohamed; Sameh E. Ahmed

2011-01-01

89

Thermodynamic analysis of the reverse Joule–Brayton cycle heat pump for domestic heating  

E-print Network

system). Finally, the air is expanded through the reciprocating expander to atmospheric pressure and exits to the atmosphere at state 4. The throttles T1 – T4 represent pressure losses in the compressor and expander inlet and exit valves, and in the heat... , is simply the reciprocal of the efficiency for an ideal gas turbine cycle, and it is notable that the expression is independent of the heat exchanger temperature drop, and hence of the thermal output, q = cp(T2?T3). For the reference operating conditions...

White, Alexander

2009-03-20

90

In-line application of electric field in capillary separation systems: Joule heating, pH and conductivity.  

PubMed

This study concerns the technique electric field-assisted capillary liquid chromatography. In this technique, an electric field is applied over the separation capillary in order to provide an additional selectivity. In this technique, the electric field is applied in-line in the separation capillary and here the electric current is the factor limiting the magnitude of applied electric field. The influence of Joule heating and other factors on the current in such systems has been investigated. The temperature in the capillary was first measured within a standard CE set-up, as function of effect per unit of length. Then the same cooling system was applied to an in-line set-up, to replicate the conditions between the two systems, and thus the temperature. Thus Joule heating effects could then be calculated within the in-line system. It was found that for systems applying an electric field in line, the direct influence from Joule heating was only relatively small. The pH in the capillary was measured in the in-line set-up using cresol red/TRIS solutions as pH probe. Significant changes in pH were observed and the results suggested that electrolysis of water is the dominant electrode reaction in the in-line system. In summary, the observed conductivity change in in-line systems was found to be mainly due to the pH change by hydrolysis of water, but primarily not due the temperature change in the capillary column. PMID:18371851

Eriksson, Björn O; Skuland, Inger Lill; Marlin, Nicola D; Andersson, Magnus B O; Blomberg, Lars G

2008-03-15

91

Transformation temperatures and shape memory characteristics of a Ti-45Ni-5Cu(at %) alloy annealed by Joule heating  

NASA Astrophysics Data System (ADS)

A temperature gradient of 75-188 K was developed in a Ti-45Ni-5Cu(at %) alloy wire with 30 mm length by Joule heating, depending on electrical power. The shape change rate increased from 0.022 to 0.045% K-1 on increasing the electrical power from 4.8 to 6.2 W. The change in the stress required for the B2-B19' transformation increased from 60 to 103 MPa on increasing the electrical power from 4.8 to 10.1 W.

Kang, Seok-Won; Cho, Gyu-Bong; Yang, Seung-Yong; Liu, Yinong; Yang, Hong; Miyazaki, Shuichi; Nam, Tae-Hyun

2010-05-01

92

Measurement and simulation of Joule heating during treatment of B-16 melanoma tumors in mice with nanosecond pulsed electric fields.  

PubMed

Experimental evidence shows that nanosecond pulsed electric fields (nsPEF) trigger apoptosis in skin tumors. We have postulated that the energy delivered by nsPEF is insufficient to impart significant heating to the treated tissue. Here we use both direct measurements and theoretical modeling of the Joule heating in order to validate this assumption. For the temperature measurement, thermo-sensitive liquid crystals (TLC) were used to determine the surface temperature while a micro-thermocouple (made from 30 ?m wires) was used for measuring the temperature inside the tissue. The calculation of the temperature distribution used an asymptotic approach with the repeated calculation of the electric field, Joule heating and heat transfer, and the subsequent readjustment of the electrical tissue conductivity. This yields a temperature distribution both in space and time. It can be shown that for the measured increase in temperature an unexpectedly high electrical conductivity of the tissue would be required, which was indeed found by using voltage and current monitoring during the experiment. Using impedance measurements within t(after)=50 ?s after the pulse revealed a fast decline of the high conductivity state when the electric field ceases. The experimentally measured high conductance of a skin fold (mouse) between plate electrodes was about 5 times higher than those of the maximally expected conductance due to fully electroporated membrane structures (G(max)/G(electroporated))?5. Fully electroporated membrane structure assumes that 100% of the membranes are conductive which is estimated from an impedance measurement at 10 MHz where membranes are capacitively shorted. Since the temperature rise in B-16 mouse melanoma tumors due to equally spaced (?t=2 s) 300 ns-pulses with E=40 kV/cm usually does not exceed ??=3 K at all parts of the skin fold between the electrodes, a hyperthermic effect on the tissue can be excluded. PMID:24680133

Pliquett, Uwe; Nuccitelli, Richard

2014-12-01

93

Heat treatment of whole milk by the direct joule effect--experimental and numerical approaches to fouling mechanisms.  

PubMed

The development of alternative technologies such as the direct Joule effect to pasteurize and sterilize food products is of great scientific and industrial interest. Our objective was 1) to gain insight into the ability to ensure ultra-high-temperature treatment of milk and 2) to investigate the links among thermal, hydraulic, and electrical phenomena in relation to fouling in a direct Joule effect heater. The ohmic heater [OH; E perpendicular to v (where E is the electrical field and v is the velocity); P (power) = 15 kW] was composed of 5 flat rectangular cells [e (space between the plate and electrode) = 15 mm, w (wall) = 76 mm, and L (length of the plate in plate heat exchanger or electrode) = 246 mm]--3 active cells to ensure heating and 2 (at the extremities) for electrical insulation and the recovery of leakage currents. In the first step, the thermal performance of the OH was investigated vs. the flow regimen [50 < Re (Reynolds number) < 5,000], supplied power (0 < P < 15 kW), and electrical conductivity of fluids (0.1 < sigma(20 degrees C) < 2 S/m) under clean conditions with model fluids. This protocol enabled a global thermal approach (thermal and electrical balance, modeling of the temperature profile of a fluid) and local analysis of the wall temperature of the electrode. An empirical correlation was established to estimate the temperature gradient, T(w)-T(b) (where T(w) is the wall temperature and T(b) is the product temperature) under clean conditions (without fouling) and was used to define operating conditions for pure-volume and direct-resistance heating. In the second step, the ability of OH to ensure the ultra-high-temperature treatment of whole milk was investigated and compared with a plate heat exchanger. Special care was taken to investigate the heat transfer phenomena occurring over a range of temperatures from 105 to 138 degrees C. This temperature range corresponds to the part of the process made critical by protein and mineral fouling. The objectives were 1) to demonstrate the ability of an OH to ensure heat treatment of milk, 2) to study the thermal and hydraulic performance with an increasing power and temperature difference between the inlet and outlet of the OH, 3) to define and validate a criterion to follow heat dissipation efficiency, and 4) to compare the fouling propensity with the different configurations. A heat dissipation coefficient, Rh(CO), was defined and validated to monitor the fouling propensity through global electrical and thermal parameters. Finally, a numerical simulation was developed to analyze heat profiles (wall, deposit, bulk). Because of an increasing Joule effect in the static deposit, the simulation showed how wall overheating would definitively cause fouling to spiral out of control. PMID:17106078

Fillaudeau, L; Winterton, P; Leuliet, J C; Tissier, J P; Maury, V; Semet, F; Debreyne, P; Berthou, M; Chopard, F

2006-12-01

94

Cycling Joule Thomson refrigerator  

NASA Technical Reports Server (NTRS)

A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

Tward, E. (inventor)

1983-01-01

95

Direct Evidence of Molecular Aggregation and Degradation Mechanism of Organic Light-Emitting Diodes under Joule Heating: an STM and Photoluminescence Study  

E-print Network

Direct Evidence of Molecular Aggregation and Degradation Mechanism of Organic Light-Emitting Diodes, 2004 The Joule heating effect on electroluminescent efficiency is important in the degradation origin) measure- ments were performed on the guest molecule BT (1,4-bis(benzothiazole-vinyl) benzene), host

Gong, Jian Ru

96

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

Microsoft Academic Search

Magnetic records from 71 stations were employed to determine the distribution of electric fields and currents in the polar ionosphere for March 17, 18, and 19, 1978. Hourly distribution maps of the Joule heat production rate, the particle energy injection rate, and their sum over the entire polar region on the three days were calculated. For constructing the hourly distribution

B.-H. Ahn; S.-I. Akasofu; Y. Kamide

1983-01-01

97

Experimental evaluation of an adaptive Joule–Thomson cooling system including silicon-microfabricated heat exchanger and microvalve components  

PubMed Central

This article reports the evaluation of a Joule–Thomson (JT) cooling system that combines two custom micromachined components—a Si/glass-stack recuperative heat exchanger and a piezoelectrically actuated expansion microvalve. With the microvalve controlling the flow rate, this system can modulate cooling to accommodate varying refrigeration loads. The perforated plate Si/glass heat exchanger is fabricated with a stack of alternating silicon plates and Pyrex glass spacers. The microvalve utilizes a lead zirconate titanate actuator to push a Si micromachined valve seat against a glass plate, thus modulating the flow passing through the gap between the valve seat and the glass plate. The fabricated heat exchanger has a footprint of 1×1?cm2 and a length of 35 mm. The size of the micromachined piezoelectrically actuated valve is about 1×1×1?cm3. In JT cooling tests, the temperature of the system was successfully controlled by adjusting the input voltage of the microvalve. When the valve was fully opened (at an input voltage of ?30 V), the system cooled down to a temperature as low as 254.5 K at 430 kPa pressure difference between inlet and outlet at steady state and 234 K at 710 kPa in a transient state. The system provided cooling powers of 75 mW at 255 K and 150 mW at 258 K. Parasitic heat loads at 255 K are estimated at approximately 700 mW. PMID:21552354

Zhu, Weibin; Park, Jong M.; White, Michael J.; Nellis, Gregory F.; Gianchandani, Yogesh B.

2011-01-01

98

Joule-Thomson effect and internal convection heat transfer in turbulent He II flow  

NASA Technical Reports Server (NTRS)

The temperature rise in highly turbulent He II flowing in tubing was measured in the temperature range 1.6-2.1 K. The effect of internal convection heat transport on the predicted temperature profiles is calculated from the two-fluid model with mutual friction. The model predictions are in good agreement with the measurements, provided that the pressure gradient term is retained in the expression for internal convection heat flow.

Walstrom, P. L.

1988-01-01

99

Numerical model and investigations of the externally heated valve Joule engine  

Microsoft Academic Search

The mineral fuels used recently, i.e., oil and gas, will be soon exploited out. This paper presents an idea of the engine where any fuel or solar heat can be used as a source of energy. The proposed model is an externally heated, 2-stroke, valve engine (EHVE). This is a piston-type engine, entirely different from the well-known Stirling one, which

Jerzy Wojewoda; Zbyszko Kazimierski

2010-01-01

100

Joule heating-induced coexisted spin Seebeck effect and spin Hall magnetoresistance in the platinum/Y{sub 3}Fe{sub 5}O{sub 12} structure  

SciTech Connect

Spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) are observed simultaneously in the Pt/Y{sub 3}Fe{sub 5}O{sub 12} hybrid structure when thermal gradient is produced by Joule heating. According to their dependences on applied current, these two effects can be separated. Their dependence on heating power and magnetic field is systematically studied. With the increase of heating power, the SSE enhances linearly, whereas the SMR decreases slowly. The origin of the spin currents is further analyzed. The heating power dependences of the spin currents associated with the SSE and the SMR are found to be different.

Wang, W. X. [State Key Laboratory of Advance Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. H.; Zou, L. K.; Cai, J. W.; Sun, J. R., E-mail: jrsun@iphy.ac.cn, E-mail: sun-zg@whut.edu.cn [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Sun, Z. G. [State Key Laboratory of Advance Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2014-11-03

101

Electrical Service and Controls for Joule Heating of a Nuclear Waste Experimental Glass Melter  

Microsoft Academic Search

Vitrification of radioactive liquid waste into glass is the best known method today for long-term storage of high radioactivity nuclear waste products. The electrical service and control system for an experimental electrically heated glass melter to handle nonradioactive materials, installed at Savannah River Laboratory, are described. Data accumulated and design and operating experience acquired in building and operating this melter

C. James Erickson; Abdul Q. Haideri

1985-01-01

102

Electrical current measurement based on Joule heating of micro-resistors  

Microsoft Academic Search

In the study, a novel micro sensor is presented for detection of measurement of electrical current, consisting of a quartz substrate and Pt resistors. As current flow through the resistor, some energy is converted to heat. The power generated in this process is related to both the voltage across the resistor and the current flowing through it, which causes a

Chia-Yen Lee; Lung-Ming Fu; Chiu-Feng Lin; Chien-Hsiung Tsai

2011-01-01

103

Effect of Joule heating and thermal radiation in flow of third grade fluid over radiative surface.  

PubMed

This article addresses the boundary layer flow and heat transfer in third grade fluid over an unsteady permeable stretching sheet. The transverse magnetic and electric fields in the momentum equations are considered. Thermal boundary layer equation includes both viscous and Ohmic dissipations. The related nonlinear partial differential system is reduced first into ordinary differential system and then solved for the series solutions. The dependence of velocity and temperature profiles on the various parameters are shown and discussed by sketching graphs. Expressions of skin friction coefficient and local Nusselt number are calculated and analyzed. Numerical values of skin friction coefficient and Nusselt number are tabulated and examined. It is observed that both velocity and temperature increases in presence of electric field. Further the temperature is increased due to the radiation parameter. Thermal boundary layer thickness increases by increasing Eckert number. PMID:24454694

Hayat, Tasawar; Shafiq, Anum; Alsaedi, Ahmed

2014-01-01

104

Effect of Joule Heating and Thermal Radiation in Flow of Third Grade Fluid over Radiative Surface  

PubMed Central

This article addresses the boundary layer flow and heat transfer in third grade fluid over an unsteady permeable stretching sheet. The transverse magnetic and electric fields in the momentum equations are considered. Thermal boundary layer equation includes both viscous and Ohmic dissipations. The related nonlinear partial differential system is reduced first into ordinary differential system and then solved for the series solutions. The dependence of velocity and temperature profiles on the various parameters are shown and discussed by sketching graphs. Expressions of skin friction coefficient and local Nusselt number are calculated and analyzed. Numerical values of skin friction coefficient and Nusselt number are tabulated and examined. It is observed that both velocity and temperature increases in presence of electric field. Further the temperature is increased due to the radiation parameter. Thermal boundary layer thickness increases by increasing Eckert number. PMID:24454694

Hayat, Tasawar; Shafiq, Anum; Alsaedi, Ahmed

2014-01-01

105

Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters  

SciTech Connect

An iron phosphate composition for vitrifying a high sulfate (~17 wt%) and high alkali (~80 wt%) low activity Hanford waste, known as AZ102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ102 which corresponded to a total alkali and sulfate (SO3) content of 21 and 4.2 wt%, respectively. A slurry (7M Na) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090°C for 10 days in a small JHM at PNNL and for 7 days in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their CCC-treated counterparts met the DOE LAW requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT). These glass waste forms retained up to 77 % of the SO3 (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium, surrogate for Tc-99, all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition (slurry feed) was melted continuously in the JHM and CCIM, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste.

Day, Delbert E.; Brow, R. K.; Ray, C. S.; Kim, Cheol-Woon; Reis, Signo T.; Vienna, John D.; Peeler, David K.; Johnson, Fabienne; Hansen, E. K.; Sevigny, Gary J.; Soelberg, Nicolas R.; Pegg, Ian L.; Gan, Hao

2012-01-05

106

Numerical calculation and experimental research on crack arrest by detour effect and joule heating of high pulsed current in remanufacturing  

NASA Astrophysics Data System (ADS)

The remanufacturing blanks with cracks were considered as irreparable. With utilization of detour effect and Joule heating of pulsed current, a technique to arrest the crack in martensitic stainless steel FV520B is developed. According to finite element theory, the finite element(FE) model of the cracked rectangular specimen is established firstly. Then, based on electro-thermo-structure coupled theory, the distributions of current density, temperature field, and stress field are calculated for the instant of energizing. Furthermore, the simulation results are verified by some corresponding experiments performed on high pulsed current discharge device of type HCPD-I. Morphology and microstructure around the crack tip before and after electro pulsing treatment are observed by optical microscope(OM) and scanning electron microscope(SEM), and then the diameters of fusion zone and heat affected zone(HAZ) are measured in order to contrast with numerical calculation results. Element distribution, nano-indentation hardness and residual stress in the vicinity of the crack tip are surveyed by energy dispersive spectrometer(EDS), scanning probe microscopy(SPM) and X-ray stress gauge, respectively. The results show that the obvious partition and refined grain around the crack tip can be observed due to the violent temperature change. The contents of carbon and oxygen in fusion zone and HAZ are higher than those in matrix, and however the hardness around the crack tip decreases. Large residual compressive stress is induced in the vicinity of the crack tip and it has the same order of magnitude for measured results and numerical calculation results that is 100 MPa. The relational curves between discharge energies and diameters of the fusion zone and HAZ are obtained by experiments. The difference of diameter of fusion zone between measured and calculated results is less than 18.3%. Numerical calculation is very useful to define the experimental parameters. An effective method to prevent further extension of the crack is presented and can provide a reference for the compressor rotor blade remanufacturing.

Yu, Jing; Zhang, Hongchao; Deng, Dewei; Hao, Shengzhi; Iqbal, Asif

2014-07-01

107

Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN/GaN LEDs  

SciTech Connect

The heat model of a light-emitting diode (LED) with an InGaN/GaN quantum well (QW) in the active region is considered. Effects of the temperature and drive current, as well as of the size and material of the heat sink on the light output and efficiency of blue LEDs are studied. It is shown that, for optimal heat removal, decreasing of the LED efficiency as current increases to 100 mA is related to the effect of electric field on the efficiency of carrier injection into the QW. As current further increases up to 400 mA, the decrease in efficiency is caused by Joule heating. It is shown that the working current of LEDs can be increased by a factor of 5-7 under optimal heat removal conditions. Recommendations are given on the cooling of LEDs in a manner dependent on their power.

Efremov, A. A. [St. Petersburg State Polytechnical University (Russian Federation)], E-mail: eartm@mail.ru; Bochkareva, N. I.; Gorbunov, R. I.; Lavrinovich, D. A.; Rebane, Yu. T.; Tarkhin, D. V.; Shreter, Yu. G. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2006-05-15

108

James Joule and meteors  

Microsoft Academic Search

1989 was the hundredth anniversary of the death of James Prescott Joule, the Prescott being his mother's family name and the Joule, rhyming with cool, originating from the Derbyshire village of Youlgreave. Joule is rightly famous for his experimental efforts to establish the law of conservation of energy, and for the fact that J, the symbol known as the mechanical

David W. Hughes

1990-01-01

109

Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters - 12240  

SciTech Connect

An iron phosphate composition for vitrifying a high sulfate (?17 wt%) and high alkali (?80 wt%) Hanford low activity waste (LAW), known as AZ-102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ-102 which corresponded to a total alkali and sulfate (represented as SO{sub 3}) content of 21 and 4.4 wt%, respectively. A slurry (7 M Na{sup +}) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090 deg. C for 10 days in a small JHM at PNNL and for 70 hours in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their canister centerline cooled (CCC) counterparts met the requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT) responses in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract. These glass waste forms retained up to 77 % of the SO{sub 3} (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium (used as a surrogate for Tc) all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition was melted continuously in a slurry fed JHM and in the US, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste. The following conclusions are drawn from the results of the present work. (1) An iron phosphate composition, designated as MS26AZ102F-2, containing 26 wt% of the simulated high sulfate (17 wt%), high alkali (80 wt%) Hanford AZ-102 LAW meets all the criteria for processing in a JHM and CCIM. This composition produces a homogeneous glass with a density of 2.80 ± 0.04 g/cm{sup 3} after melting between 1000 and 1050 deg. C for 3 to 5 h. (2) This is the first time that an iron phosphate glass was melted in the JHM continuously for 10 days achieving a specific melting rate of 1010 kg/m2/day and in the CCIM for 70 hrs with a melting rate of 664 kg/m{sup 2}/day. (3) The analyzed (ICP-AES) compositions for all the glasses prepared under several melting conditions are in excellent agreement with the target composition. The variation of melting conditions include: (i) use of small scale/short melting time to large scale/long melting time (300 g to 80 kg, 4 h to 10 days) operations including melting in the JHM and CCIM, (ii) use of dry or wet (slurry) melter feed, (iii) addition of reductant (sugar) in the batch, and (iv) bubbling the melt with air. (4) The chemical durability as measured by PCT and VHT for the quenched and CCC-treated waste forms prepared from laboratory, JHM or CCIM melting exceeds the DOE requirements for LAW. (5) Depending upon the melting time (4 h to 10 days), the average concentration of SO{sub 3} in the MS26AZ102F-2 iron phosphate glass waste form varies from about 1.78 (RSM) to 3.74 (laboratory melt) wt% which corresponds to an SO{sub 3} retention of 41 to 86% when melted between 1030 at 1050 deg. C in air. (6) The retention of SO{sub 3} in the glass was reduced when a reductant (sugar) was added to the slurry. (7) The retention of other problem components like Cesium and Rhenium/Tc-99 is also high; from 92 to 100% for Cs{sub 2}O under different melting conditions, and from 66 to 33% for Re{sub 2}O{sub 7} for melts processed from 3 to 5 hours and up to 10 days. (8) Corrosion tests on Inconel 693 and K-3 refractory at temperatures between 1000 and 1050 deg. C indicate that both materials should be suitable for melting iron phosphate glasses. (9) The viscosity and electrical conductivity of the MS26AZ102F-2 melt are within the acceptable limits for RSM and CCIM processing. (10)This work has shown that iron phosphate compositions are a pot

Day, Delbert E.; Brow, Richard K.; Ray, Chandra S.; Reis, Signo T. [Missouri University of Science and Technology, 1870 Miner Circle, Rolla, MO 65409 (United States); Kim, Cheol-Woon [MO-SCI Corporation, 4040 HyPoint North, Rolla, MO 65401 (United States); Vienna, John D.; Sevigny, Gary [Pacific North West National Laboratory, Battelle Blvd., Richland, WA 99352 (United States); Peeler, David; Johnson, Fabienne C.; Hansen, Eric K. [Savannah River National Laboratory, Savannah River Site, 999-W, Aiken, SC 29803 (United States); Soelberg, Nick [Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID 83415 (United States); Pegg, Ian L.; Gan, Hao [Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States)

2012-07-01

110

The generalized electromagnetic equations and their application: Joule heat (or superconductivity) relative to the generation (or prohibited generation) of net electric charges in a conductor carrying current  

E-print Network

Basing on the conservation law of electric charge and differential geometry, with consulting Maxwell equations, we propose in this paper a set of generalized electromagnetic equations of isotropic media. Maxwell equations can be derived from these equations under certain conditions. And London equations are the special case of them only. These equations are compatible with the Ginzburg-Landau equations and are expected to be valid not only for the normal electromagnetic phenomena but also for the superconducting ones. As the simple applications, we derive the Ohm's law from these equations with the condition of an infinitely long straight circular wire carrying a stationary current; and show that the Joule heat is relative to the net electric charges generated in the wire, which leads to such an interesting picture: for a steady current, the normal state is that arousing net electric charges with the current; while the superconducting state is that prohibiting the generation of net electric charges. In the re...

She, Weilong

2011-01-01

111

Joule heating effect on oxide whisker growth induced by current stressing in Cu/Sn-58Bi/Cu solder joint  

NASA Astrophysics Data System (ADS)

The electromigration test was conducted in Cu/Sn-58Bi/Cu solder joint with high current density of 104 A/ cm2. Results showed that a large number of whiskers with natural weed appearance were observed at the cathode side in such a short current stressing time. Furthermore, some secondary whiskers were attached to the primary whiskers, which has never been reported before. We presumed the vapor-solid (VS) mechanism to explain the oxide whiskers growth, which was quite different from the traditional theory that the compressive stress took on the driving force. In conclusion, due to the over-Joule heating effect, the metal oxide whiskers were synthesized in bulk quantities by thermal evaporation of Sn oxide and Bi oxide.

He, Hongwen; Cao, Liqiang; Wan, Lixi; Zhao, Haiyan; Xu, Guangchen; Guo, Fu

2012-08-01

112

The Mayer-Joule Principle: The Foundation of the First Law of Thermodynamics  

NASA Astrophysics Data System (ADS)

To most students today the mechanical equivalent of heat, called the Mayer-Joule principle, is simply a way to convert from calories to joules and vice versa. However, in linking work and heat—once thought to be disjointed concepts—it goes far beyond unit conversion. Heat had eluded understanding for two centuries after Galileo Galilei constructed an early thermometer. Independently, Julius Robert Mayer and James Prescott Joule found the connection between heat and work, the Mayer-Joule principle.

Newburgh, Ronald; Leff, Harvey S.

2011-11-01

113

Influence of surface displacement on solid state flow induced by horizontally heterogeneous Joule heating in the inner core of the Earth  

NASA Astrophysics Data System (ADS)

We investigate the influence of surface displacement on fluid motions induced by horizontally heterogeneous Joule heating in the inner core. The difference between the governing equations and those of Takehiro (2011) is the boundary conditions at the inner core boundary (ICB). The temperature disturbance at the ICB coincides with the melting temperature, which varies depending on the surface displacement. The normal component of stress equalizes with the buoyancy induced by the surface displacement. The toroidal magnetic field and surface displacement with the horizontal structure of Y20 spherical harmonics is given. The flow fields are calculated numerically for various amplitudes of surface displacement with the expected values of the parameters of the core. Further, by considering the heat balance at the ICB, the surface displacement amplitude is related to the turbulent velocity amplitude in the outer core, near the ICB. The results show that when the turbulent velocity is on the order of 10-1 -10-2 m/s, the flow and stress fields are similar to those of Takehiro (2011), where the surface displacement vanishes. As the amplitude of the turbulent velocity decreases, the amplitude of the surface displacement increases, and counter flows from the polar to equatorial regions emerge around the ICB, while flow in the inner regions is directed from the equatorial to polar regions, and the non-zero radial component of velocity at the ICB remains. When the turbulent velocity is on the order of 10-4 -10-5 m/s, the radial component of velocity at the ICB vanishes, the surface counter flows become stronger than the flow in the inner region, and the amplitude of the stress field near the ICB dominates the inner region, which might be unsuitable for explaining the elastic anisotropy in the inner core.

Takehiro, Shin-ichi

2015-04-01

114

James Prescott Joule and the Unit of Energy  

Microsoft Academic Search

A CENTURY has passed since Joule read his paper on the relation between heat and work at the meeting of the British Association at Cork on August 26, 1843. It is unfortunate that a difference of opinion has arisen about the correct pronunciation of his name and also of the word joule used to denote a unit of energy (ten

H. S. Allen

1943-01-01

115

Influence of Cu column under-bump-metallizations on current crowding and Joule heating effects of electromigration in flip-chip solder joints  

NASA Astrophysics Data System (ADS)

The electromigration behavior of SnAg solder bumps with and without Cu column under-bump-metallizations (UBMs) has been investigated under a current density of 2.16 × 104 A/cm2 at 150 °C. Different failure modes were observed for the two types of samples. In those without Cu column UBMs, when SnAg solder bumps that had implemented 2 ?m Ni UBMs were current stressed at 2.16 × 104 A/cm2, open failure occurred in the bump that had an electron flow direction from the chip side to the substrate side. However, in those with Cu column UBMs, cracks formed along the interface of Cu6Sn5 intermetallic compounds and the solder on the substrate side in the Sn-3.0Ag-0.5Cu solder bump that had an electron flow direction from the substrate side to the chip side. A three-dimensional simulation of the current density distribution was performed in order to obtain a better understanding of the current crowding behavior in solder bumps. The current crowding effect was found to account for the void formation on both the chip and the substrate side for the two kinds of solder bumps. One more important finding, as confirmed by infrared microscopy, is that the alleviation of current crowding by Cu column UBMs also helped decrease the Joule heating effect in solder bumps during current stressing. Therefore, the measured failure time for the solder joints with Cu column UBMs appears to be much longer than that of the ones with the 2 ?m Ni UBMs.

Liang, Y. C.; Tsao, W. A.; Chen, Chih; Yao, Da-Jeng; Huang, Annie T.; Lai, Yi-Shao

2012-02-01

116

Joule-Heated Ceramic-Lined Melter to Vitrify Liquid Radioactive Wastes Containing Am241 Generated From MOX Fuel Fabrication in Russia  

SciTech Connect

The governments of the United Stated of America and the Russian Federation (RF) signed an Agreement September 1, 2000 to dispose of weapons plutonium that has been designated as no longer required for defense purposes. The Agreement declares that each country will disposition 34MT of excess weapons grade plutonium from their stockpiles. The preferred disposition technology is the fabrication of mixed oxide (MOx) fuel for use or burning in pressurized water reactors to destroy the plutonium. Implementation of this Agreement will require the conversion of plutonium metal to oxide and the fabrication of MOx fuel within the Russian Federation. The MOx fuel fabrication and metal to oxide conversion processes will generate solid and liquid radioactive wastes containing trace amounts of plutonium, neptunium, americium, and uranium requiring treatment, storage, and disposal. Unique to the Russian MOx fuel fabrication facility's flow-sheet is a liquid waste stream with high concentrations ({approx}1 g/l) of {sup 241}Am and non radioactive silver. The silver is used to dissolve PuO{sub 2} feed materials to the MOx fabrication facility. Technical solutions are needed to treat and solidify this liquid waste stream. Alternative treatment technologies for this liquid waste stream are being evaluated by a Russian engineering team. The technologies being evaluated include borosilicate and phosphate vitrification alternatives. The evaluations are being performed at a conceptual design level of detail under a Lawrence Livermore National Laboratory (LLNL) contract with the Russian organization TVEL using DOE NA-26 funding. As part of this contract, the RF team is evaluating the technical and economic feasibility of the US borosilicate glass vitrification technology based on a Duratek melter to solidify this waste stream into a form acceptable for storage and geologic disposal. The composition of the glass formed from treating the waste is dictated by the concentration of silver and americium it contains. Silver is widely used as an additive in glass making. However, its solubility is known to be limited in borosilicate glasses. Further, silver, which is present as a nitrate salt in the waste, can be easily reduced to molten silver in the melting process. Molten silver, if formed, would be difficult to reintroduce into the glass matrix and could pose operating difficulties for the glass melter. This will place a limitation on the waste loading of the melter feed material to prevent the separation of silver from the waste within the melter. If the silver were recovered in the MOx fabrication process, which is currently under consideration, the composition of the glass would likely be limited only by the thermal heat load from the incorporated {sup 241}Am. The resulting mass of glass used to encapsulate the waste could then be reduced by a factor of approximately three. The vitrification process used to treat the waste stream is proposed to center on a joule-heated ceramic lined slurry fed melter. Glass furnaces of this type are used in the United States to treat high-level waste (HLW) at the: Defense Waste Processing Facility, West Valley Demonstration Project, and to process the Hanford tank waste. The waste will initially be blended with glass-forming chemicals, which are primarily sand and boric acid. The resulting slurry is pumped to the melter for conversion to glass. The melter is a ceramic lined metal box that contains a molten glass pool heated by passing electric current through the glass. Molten glass from the melter is poured into canisters to cool and solidify. They are then sealed and decontaminated to form the final waste disposal package. Emissions generated in the melter from the vitrification process are treated by an off-gas system to remove radioactive contamination and destroy nitrogen oxides (NOx).

Smith, E C; Bowan II, B W; Pegg, I; Jardine, L J

2004-11-16

117

The Mayer-Joule Principle: The Foundation of the First Law of Thermodynamics  

ERIC Educational Resources Information Center

To most students today the mechanical equivalent of heat, called the Mayer-Joule principle, is simply a way to convert from calories to joules and vice versa. However, in linking work and heat--once thought to be disjointed concepts--it goes far beyond unit conversion. Heat had eluded understanding for two centuries after Galileo Galilei…

Newburgh, Ronald; Leff, Harvey S.

2011-01-01

118

A Joule Museum at Manchester  

Microsoft Academic Search

THE support of the University of Manchester and the British Society for the History of Science has been secured for the arrangement of a small museum to commemorate the work of James Prescott Joule, the discoverer of the Law of Conservation of Energy. Besides showing various original instruments and documents which belonged to Joule, it is planned to display reconstructions

L. Rosenfeld

1950-01-01

119

Memoir of James Prescott Joule  

NASA Astrophysics Data System (ADS)

1. Introduction; 2. Parentage and early life; 3. Joule's first research; 4. Second research; 5. Third research; 6. Efforts to convince the scientific world; 7. The year 1847; 8. Joule's views accepted by Thomson, Rankine, and Clausius; 9. Middle life; 10. Later life; Appendix to page 18; Note A to page 88; Index.

Reynolds, Osborne

2011-06-01

120

Watt and joule balances  

NASA Astrophysics Data System (ADS)

The time is fast approaching when the SI unit of mass will cease to be based on a single material artefact and will instead be based upon the defined value of a fundamental constant—the Planck constant—h . This change requires that techniques exist both to determine the appropriate value to be assigned to the constant, and to measure mass in terms of the redefined unit. It is important to ensure that these techniques are accurate and reliable to allow full advantage to be taken of the stability and universality provided by the new definition and to guarantee the continuity of the world's mass measurements, which can affect the measurement of many other quantities such as energy and force. Up to now, efforts to provide the basis for such a redefinition of the kilogram were mainly concerned with resolving the discrepancies between individual implementations of the two principal techniques: the x-ray crystal density (XRCD) method [1] and the watt and joule balance methods which are the subject of this special issue. The first three papers report results from the NRC and NIST watt balance groups and the NIM joule balance group. The result from the NRC (formerly the NPL Mk II) watt balance is the first to be reported with a relative standard uncertainty below 2 × 10-8 and the NIST result has a relative standard uncertainty below 5 × 10-8. Both results are shown in figure 1 along with some previous results; the result from the NIM group is not shown on the plot but has a relative uncertainty of 8.9 × 10-6 and is consistent with all the results shown. The Consultative Committee for Mass and Related Quantities (CCM) in its meeting in 2013 produced a resolution [2] which set out the requirements for the number, type and quality of results intended to support the redefinition of the kilogram and required that there should be agreement between them. These results from NRC, NIST and the IAC may be considered to meet these requirements and are likely to be widely debated prior to a decision on redefinition. The CCM had already recognized that agreement was close and has set in place a process whereby redefinition can take place by 2018. The final decision will be in the hands of the Conférence Générale des Poids et Mesures (CGPM) but the results reported here should aid a positive decision. Figure 1. Figure 1. Results from recent measurements of the Planck constant. The reference for the results h 90 is derived from the conventional values of the Josephson constant K J-90 and the von Klitzing constant R K-90. The factor of ten improvement in uncertainty of the NRC watt balance result, over that achieved by the same apparatus at NPL a few years earlier, can be understood as a factor of five improvement arising from the elimination of an effect discovered at NPL that could not be eliminated before shipment to Canada and a factor of two arising from the considerable improvements made by NRC. Once the kilogram has been redefined, the watt and joule balances will complete their transitions from instruments that are primarily of interest to the electrical community for determining the SI electrical units from the mechanical units, to the principal methods by which an individual National Measurement Institute (NMI) can make an independent determination of the SI unit of mass and thereby contribute to the maintenance of national and international mass scales. This special issue gives an introduction to the diversity of techniques which are required for the operation of watt and joule balances. However it does not contain a review of existing balances; this was a deliberate decision, as a number of such review papers have been published in the past five years [3-7] and it was felt that it was not yet time for another. The first technique considered is that of gravimetry; the watt balance measures the weight Mg of a mass M , and to convert the measured weight into a mass, the value of the acceleration due to gravity g must be known, at the time of the weighing and at the centre of gravity of the mass. The paper by Liard and his co-au

Robinson, Ian A.

2014-04-01

121

Effect of the joule heating on the quantum efficiency and choice of thermal conditions for high-power blue InGaN\\/GaN LEDs  

Microsoft Academic Search

The heat model of a light-emitting diode (LED) with an InGaN\\/GaN quantum well (QW) in the active region is considered. Effects\\u000a of the temperature and drive current, as well as of the size and material of the heat sink on the light output and efficiency\\u000a of blue LEDs are studied. It is shown that, for optimal heat removal, decreasing of

A. A. Efremov; N. I. Bochkareva; R. I. Gorbunov; D. A. Lavrinovich; Yu. T. Rebane; D. V. Tarkhin; Yu. G. Shreter

2006-01-01

122

The Mayer-Joule Principle: The Foundation of the First Law of Thermodynamics  

Microsoft Academic Search

To most students today the mechanical equivalent of heat, called the Mayer-Joule principle, is simply a way to convert from calories to joules and vice versa. However, in linking work and heat--once thought to be disjointed concepts--it goes far beyond unit conversion. Heat had eluded understanding for two centuries after Galileo Galilei constructed an early thermometer. Independently, Julius Robert Mayer

Ronald Newburgh; Harvey S. Leff

2011-01-01

123

Multicomponent gas sorption Joule-Thomson refrigeration  

NASA Technical Reports Server (NTRS)

The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

Jones, Jack A. (inventor); Petrick, S. Walter (inventor); Bard, Steven (inventor)

1991-01-01

124

Multistate memory devices based on free-standing VO2/TiO2 microstructures driven by Joule self-heating.  

PubMed

Two-terminal multistate memory elements based on VO(2)/TiO(2) thin film microcantilevers are reported. Volatile and non-volatile multiple resistance states are programmed by current pulses at temperatures within the hysteretic region of the metal-insulator transition of VO(2). The memory mechanism is based on current-induced creation of metallic clusters by self-heating of micrometric suspended regions and resistive reading via percolation. PMID:22528823

Pellegrino, Luca; Manca, Nicola; Kanki, Teruo; Tanaka, Hidekazu; Biasotti, Michele; Bellingeri, Emilio; Siri, Antonio Sergio; Marré, Daniele

2012-06-01

125

From Joule to Caratheodory and Born: A Conceptual Evolution of the First Law of Thermodynamics  

ERIC Educational Resources Information Center

In the years after Joule's experiment on the equivalence of heat and work, it was taken for granted that heat and work could be independently defined and that the change in energy for a change of state is the sum of the heat and the work. Only with the work of Caratheodory and Born did it become clear that heat cannot be measured independently,…

Rosenberg, Robert M.

2010-01-01

126

A Virial Treatment of the Joule and Joule-Thomson Coefficients.  

ERIC Educational Resources Information Center

Provides background information designed to aid a physical chemistry student in using the virial equation of state in deriving expressions for other thermodynamic properties, such as writing the Joule and Joule-Thomson coefficients in terms of virial expansions. (CS)

Rybolt, Thomas R.

1981-01-01

127

Energy deposition by precipitating particles and Joule dissipation in the auroral ionosphere  

Microsoft Academic Search

Eight days of synoptic data from the Chatanika incoherent scatter radar have been analyzed in an attempt to determine the characteristic morphology of auroral zone energy deposition by Joule heating and precipitating particles. The observations cover invariant latitudes between approx.62° and 68°. The composite spatial morphology derived from these eight days of data shows that morning sector particle precipitation deposits

James F. Vickrey; Richard R. Vondrak; Stephen J. Matthews

1982-01-01

128

Manganese Nitride Sorption Joule-Thomson Refrigerator  

NASA Technical Reports Server (NTRS)

Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

Jones, Jack A.; Phillips, Wayne M.

1992-01-01

129

Application of vanadium hydride compressors for Joule-Thomson cryocoolers  

NASA Astrophysics Data System (ADS)

The Joule-Thomson expansion of hydrogen gas offers efficient and reliable cryocoolers to produce temperatures between 10 and 50 K. A critical component to the development of these devices is the metal hydride storage bed that provides a nonmechanical method to compress hydrogen gas via the reversible absorption by appropriate metals or alloys. A thermodynamic model has been used to calculate the impact of operational parameters such as input/output pressure ratios and bed temperature on energy balance and system efficiency. Detailed comparisons are reported for a compressor which utilizes vanadium metal as the sorbent for either hydrogen or deuterium where the unusually large isotope differences between the phase diagrams and thermal properties for VH(x) and VD(x) have been considered. The sensitivity of heat input requirements to the uncertainties in primary variables are described.

Bowman, R. C., Jr.; Freeman, B. D.; Phillips, J. R.

130

Joule-Thomson Cooler Produces Nearly Constant Temperature  

NASA Technical Reports Server (NTRS)

Improved Joule-Thomson cooler maintains nearly constant temperature. Absolute-pressure relief valve helps stabilize temperature of cold head despite variations in atmospheric pressure. Feedback-controlled electrical heater provides additional stabilization. Demand-flow Joule-Thomson valve requires less nitrogen than fixed-orifice Joule-Thomson valve providing same amount of cooling. Provides stable low temperatures required for operation of such devices as tunable diode lasers in laboratory and balloon-borne instruments detecting contaminants in atmosphere.

Bard, Steven; Wu, Jiunn-Jeng; Trimble, Curtis A.

1992-01-01

131

Mega-joule experiment area study, 1989  

SciTech Connect

This document contains Chapters 3 and 4 from the Mega-Joule Experiment Area Study, 1989. Water frost on the first containment wall is studied in detail in Chapter 3. Considered topics are the computer modeling of frost ablation and shock propagation and the experimental characterization of water frost. The latter is broken down into: frost crystal morphology, experiment configuration, growth rate results, density results, thermal conductivity, crush strength of frost, frost integrity, frost response to simulated soft x-rays. Chapter 4 presents information on surrounding shielding and structures to include: cryogenic spheres for first wall and coolant containment; shield tank concerning primary neutron and gamma ray shielding; and secondary shielding.

Slaughter, D.; Oirth, C.; Woodworth, J.

1995-03-09

132

Improving Control in a Joule-Thomson Refrigerator  

NASA Technical Reports Server (NTRS)

A report discusses a modified design of a Joule-Thomson (JT) refrigerator under development to be incorporated into scientific instrumentation aboard a spacecraft. In most other JT refrigerators (including common household refrigerators), the temperature of the evaporator (the cold stage) is kept within a desired narrow range by turning a compressor on and off as needed. This mode of control is inadequate for the present refrigerator because a JT-refrigerator compressor performs poorly when the flow from its evaporator varies substantially, and this refrigerator is required to maintain adequate cooling power. The proposed design modifications include changes in the arrangement of heat exchangers, addition of a clamp that would afford a controlled heat leak from a warmer to a cooler stage to smooth out temperature fluctuations in the cooler stage, and incorporation of a proportional + integral + derivative (PID) control system that would regulate the heat leak to maintain the temperature of the evaporator within a desired narrow range while keeping the amount of liquid in the evaporator within a very narrow range in order to optimize the performance of the compressor. Novelty lies in combining the temperature- and cooling-power-regulating controls into a single control system.

Borders, James; Pearson, David; Prina, Mauro

2005-01-01

133

Ultra-high temperature stability Joule-Thomson cooler with capability to accomodate pressure variations  

NASA Technical Reports Server (NTRS)

A Joule-Thomson cryogenic refrigeration system capable of achieving high temperature stabilities in the presence of varying temperature, atmospheric pressure, and heat load is provided. The Joule-Thomson cryogenic refrigeration system includes a demand flow Joule-Thomson expansion valve disposed in a cryostat of the refrigeration system. The expansion valve has an adjustable orifice that controls the flow of compressed gas therethrough and induces cooling and partial liquefaction of the gas. A recuperative heat exchanger is disposed in the cryostat and coupled to the expansion valve. A thermostatically self-regulating mechanism is disposed in the cryostat and coupled to the J-T expansion valve. The thermostatically self-regulating mechanism automatically adjusts the cross sectional area of the adjustable valve orifice in response to environmental temperature changes and changes in power dissipated at a cold head. A temperature sensing and adjusting mechanism is coupled to a cold head for adjusting the temperature of the cold head in response to the change in heat flow in the cold head. The temperature sensing and adjusting mechanism comprises a temperature sensitive diode, a wound wire heater, and an electrical feedback control circuit coupling the diode to the heater. An absolute pressure relief valve is interposed between the output of the cryostat and an exhaust port for maintaining a constant exhaust temperature in the refrigerating system, independent of the changes in atmospheric pressure.

Bard, Steven (inventor); Wu, Jiunn-Jeng (inventor); Trimble, Curtis A. (inventor)

1992-01-01

134

Joule Equivalent of Electrical Energy by Dr. James E. Parks  

E-print Network

Joule Equivalent of Electrical Energy by Dr. James E. Parks Department of Physics and Astronomy 401 the laws of mechanics and electricity and magnetism. Sir James Joule first studied the equivalence, 2013 by James Edgar Parks* *All rights are reserved. No part of this publication may be reproduced

Tennessee, University of

135

James Prescott Joule and the Unit of Energy  

Microsoft Academic Search

PROF. H. S. ALLEN'S communication in NATURE of September 25 prompts me to mention a recent conversation which I had with a Manchester man whose evidence I should have considered trustworthy. He mentioned that in his youth he had known a man who had been well acquainted with Joule, and that he had told him that Joule himself always pronounced

A. W. V. Mace

1943-01-01

136

James Prescott Joule and the Unit of Energy  

Microsoft Academic Search

ALTHOUGH it appears from earlier letters1 that no definite agreement can be reached about the pronunciation of `Joule', the following points may be of interest concerning a possible origin of the name and of its different pronunciations. According to A. Schuster and A. E. Shipley2: ``Joule's name appears to be derived from `Youlgrave', a village in Derbyshire where his family

K. R. Webb

1943-01-01

137

Minimal Joule dissipation models of magnetospheric convection  

NASA Technical Reports Server (NTRS)

This paper gives a topical review of theoretical models of magnetospheric convection based on the concept of minimal Joule dissipation. A two-dimensional slab model of the ionosphere featuring an enhanced conductivity auroral oval is used to compute high-latitude electric fields and currents. Mathematical methods used in the modeling include Fourier analysis, fast Fourier transforms, and variational calculus. Also, conformal transformations are introduced in the analysis, which enable the auroral oval to be represented as a nonconcentric, crescent-shaped figure. Convection patterns appropriate to geomagnetic quiet and disturbed conditions are computed, the differentiating variable being the relative amount of power dissipated in the magnetospheric ring current. When ring current dissipation is small, the convection electric field is restricted to high latitudes (shielding regime), and when it is large, a significant penetration of the field to low latitudes occurs, accompanied by an increase in the ratio of the region I current to the region 2 current.

Barbosa, D. D.

1988-01-01

138

Nanometer-scale temperature imaging for independent observation of Joule and Peltier effects in phase change memory devices  

SciTech Connect

This paper reports a technique for independent observation of nanometer-scale Joule heating and thermoelectric effects, using atomic force microscopy (AFM) based measurements of nanometer-scale temperature fields. When electrical current flows through nanoscale devices and contacts the temperature distribution is governed by both Joule and thermoelectric effects. When the device is driven by an electrical current that is both periodic and bipolar, the temperature rise due to the Joule effect is at a different harmonic than the temperature rise due to the Peltier effect. An AFM tip scanning over the device can simultaneously measure all of the relevant harmonic responses, such that the Joule effect and the Peltier effect can be independently measured. Here we demonstrate the efficacy of the technique by measuring Joule and Peltier effects in phase change memory devices. By comparing the observed temperature responses of these working devices, we measure the device thermopower, which is in the range of 30 ± 3 to 250 ± 10 ?V K{sup ?1}. This technique could facilitate improved measurements of thermoelectric phenomena and properties at the nanometer-scale.

Grosse, Kyle L. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Pop, Eric [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); King, William P., E-mail: wpk@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2014-09-15

139

Mixed refrigerant Joule-Thomson sorption cryocoolers  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) sorption cryocooling is the most mature technology for cooling from a normal Room-Temperature (RT) down to temperatures below 100 K in the absence of moving parts. Therefore, high reliability and no vibrations are attainable, in comparison with other cryocoolers. Cooling to 80 - 100 K with JT cryocoolers is often implemented with pure nitrogen. Alternatively, mixed refrigerants have been suggested for reducing the operating pressures to enable closed cycle cryocooling. There is a variety of publications describing nitrogen sorption cryocoolers with different configurations of sorption compressors. In the present research we suggest a novel sorption JT cryocooler that operates with a mixed refrigerant. Merging of sorption cryocooling and a mixed refrigerant enables the use of a simple, single stage compressor for cooling to 80 - 100 K, lower operating temperatures of the sorption cycle, and thus - reduced power consumption. In previous studies we have analyzed sorption compressors for mixed gases and mixed refrigerants for JT cryocoolers, separately. In this paper the option of mixed refrigerant sorption JT cryocoolers is explored. The considerations for developing mixed refrigerants to be driven by sorption compressors and to be utilized with JT cryocoolers are provided. It appears that, unlike with pure nitrogen, mixed refrigerants can be suitable for JT cryocooling with a single stage sorption compressor.

Tzabar, Nir; Grossman, Gershon

2014-01-01

140

An analysis of electrothermodynamic heating and cooling  

E-print Network

, albeit at the expense of the Joule heating within the conductor. This investigation explores the dynamic nature of thermoelectrically cooled/heated regions in effort to gain a greater understanding of the transient application of thermoelectricity...

Honea, Mark Stephen

1998-01-01

141

Program For Joule-Thomson Analysis Of Mixed Cryogens  

NASA Technical Reports Server (NTRS)

JTMIX computer program predicts ideal and realistic properties of mixed gases at temperatures between 65 and 80 K. Performs Joule-Thomson analysis of any gaseous mixture of neon, nitrogen, various hydrocarbons, argon, oxygen, carbon monoxide, carbon dioxide, and hydrogen sulfide. When used in conjunction with DDMIX computer program of National Institute of Standards and Technology (NIST), JTMIX accurately predicts order-of-magnitude increases in Joule-Thomson cooling capacities occuring when various hydrocarbons added to nitrogen. Also predicts boiling temperature of nitrogen depressed from normal value to as low as 60 K upon addition of neon. Written in Turbo C.

Jones, Jack A.; Lund, Alan

1994-01-01

142

a Numerical Study on the Performance of the Miniature Joule-Thomson Refrigerator  

NASA Astrophysics Data System (ADS)

Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, and missile homing head and guidance systems, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. The cool-down time, the temperature at the cold end, the running time and the gas consumption are the important indicators of the performance of the Joule-Thomson refrigerator. In this study, a simplified one-dimensional model of momentum and energy transport for the recuperative heat exchanger was adopted to predict the thermodynamic behaviors of the refrigerator. In the analysis, to consider the thermal interactions of the each component of the refrigerator, the momentum and energy equations for the high pressure gas, the low pressure gas, the tube, the Dewar, and the mandrel were simultaneously solved. The thermodynamic properties from the REFPROP were used to account the real gas effects of the gas. The results show the effects of the supply pressure of gas on the transient behaviors of the temperature at the cold end and the thermal performance of the recuperative heat exchanger.

Hong, Y. J.; Park, S. J.; Choi, Y. D.

2010-04-01

143

The similarity law for the Joule-Thomson inversion line.  

PubMed

We show that the expression for the Joule-Thomson inversion temperature following from the van der Waals equation and recorded in a form reduced to the Boyle values has a universal character and can be applied to many real substances and model systems. PMID:25271782

Apfelbaum, E M; Vorob'ev, V S

2014-10-23

144

James Prescott Joule and the Unit of Energy  

Microsoft Academic Search

FURTHER to Prof. H. S. Allen's communication in NATURE of September 25, I may say that Joule used to live not far from my home at Sale, near Manchester, and I have often seen his house. His name was pronounced `Joole', thus confirming Prof. G. W. O. Howe's pronunciation.

Graham Renshaw

1943-01-01

145

James Prescott Joule and the idea of energy  

Microsoft Academic Search

To commemorate the centenary of Joule's death, this article offers a brief account of the origins and development of his ideas and their incorporation into mainstream physics. The scientific, technological and social importance of his work is explained and he is shown to be a quintessential physicist.

Donald Cardwell

1989-01-01

146

James Prescott Joule and the Unit of Energy  

Microsoft Academic Search

PROF. ALLEN'S inquiries (NATURE, September 25, p. 354) confirm the conclusion reached by the late Prof. Lloyd James and reported in the Radio Times in February 1933. He found that twelve near relatives and friends of the man himself pronounced `Joule' to rhyme with cool, six more distant relatives and friends rhymed it with coal and nine other friends rhymed

J. H. Awbery

1943-01-01

147

James Prescott Joule and the idea of energy  

NASA Astrophysics Data System (ADS)

To commemorate the centenary of Joule's death, this article offers a brief account of the origins and development of his ideas and their incorporation into mainstream physics. The scientific, technological and social importance of his work is explained and he is shown to be a quintessential physicist.

Cardwell, Donald

1989-05-01

148

Determination of cyclamate in low joule foods by capillary zone electrophoresis with indirect ultraviolet detection  

Microsoft Academic Search

A rapid method for the determination of cyclamate in low joule cordials and other low joule foods by capillary zone electrophoresis (CZE) with indirect ultraviolet (UV) detection at 254 nm is described. Sorbic acid, which is often added to low joule cordials as a preservative, can also be determined with this procedure. Cyclamate and sorbate are well separated from the

Catherine O. Thompson; V. Craige Trenerry; Bridget Kemmery

1995-01-01

149

Coils and the Electromagnet Used in the Joule Balance at the NIM  

E-print Network

In the joule balance developed at National Institute of Metrology (NIM), the dynamic phase of a watt balance is replaced by the mutual inductance measurement in an attempt to provide an alternative method for the kg redefinition. But for this method a rather large current in the exciting coil, is needed to offer the necessary magnetic field in the force weighing phase, and the coil heating becomes an important uncertainty source. To reduce coil heating, a new coil system, in which a ferromagnetic material is used to increase the magnetic field was designed recently. But adopting the ferromagnetic material brings the difficulty from the nonlinear characteristic of material. This problem can be removed by measuring the magnetic flux linkage difference of the suspended coil at two vertical positions directly to replace the mutual inductance parameter. Some systematic effects of this magnet are discussed.

Zhang, Zhonghua; Han, Bing; Lu, Yunfeng; Li, Shisong; Xu, Jinxin; Wang, Gang

2015-01-01

150

Joule-Thomson coefficient of ideal anyons within fractional exclusion statistics  

SciTech Connect

The analytical expressions of the Joule-Thomson coefficient for homogeneous and harmonically trapped three-dimensional ideal anyons which obey Haldane fractional exclusion statistics are derived. For an ideal Fermi gas, the Joule-Thomson coefficient is negative, which means that there is no maximum Joule-Thomson inversion temperature. With careful study, it is found that there exists a Joule-Thomson inversion temperature in the fractional exclusion statistics model. Furthermore, the relations between the Joule-Thomson inversion temperature and the statistical parameter g are investigated.

Qin Fang; Chen Jisheng [Physics Department and Institute of Nanoscience and Nanotechnology, Central China Normal University, Wuhan 430079 (China)

2011-02-15

151

Heat Conduction and Thermal Stress Analyses of a Strip with Semi-Elliptical Notch Under Electric Current  

Microsoft Academic Search

An electric current is applied in a thin strip conductor with an edge crack or a semi-elliptical notch. The electric current gives rise to two states, i.e., uniform and uneven Joule heat. The Joule heat gives rise to the temperature, and thus the heat flux and also free thermal expansion. Using a rational mapping function, problems of the electrical current,

Norio Hasebe

2010-01-01

152

Proceedings of HT '05 2005 ASME Heat Transfer Conference  

E-print Network

fluxes, which is often called the inverse heat con- duction problem. Heating rate can also be estimated to affect the decay rate, which is necessary to achieve rea- sonable heating rate measurement. The measurements of heating rate are used to determine the volumetric generation rate (Joule heating) and the heat

Walker, D. Greg

153

On the possible cycles via the unified perspective of cryocoolers. Part A: The Joule-Thomson cryocooler  

SciTech Connect

Joule-Thomson (JT) cryocoolers possess a self adjusting effect, which preserves the state of the returning stream from the evaporator as a saturated vapor. The heat load can be entirely absorbed at constant temperature by evaporation even for different sized heat exchangers. It is not possible for the steady state flow resulting from a gradual cool down to penetrate 'deeper' into the two-phase dome, and produce a two phase return flow even with a heat exchanger of unlimited size. Such behavior was implicitly taken for granted in the literature but never clearly stated nor questioned and therefore never systematically proven. The discussion provided below provides such a proof via the unified model of cryocoolers. This model portrays all cryocoolers as magnifiers of their respective elementary temperature reducing mechanism through the process of 'interchanging'.

Maytal, Ben-Zion [Rafael, Ltd., P.O. Box 2250, Haifa 3102102 (Israel); Pfotenhauer, John M. [University of Wisconsin-Madison, Madison, WI 53706 (United States)

2014-01-29

154

Joule-Thomson cryogenic cooler with extremely high thermal stability  

NASA Technical Reports Server (NTRS)

An 80-K Joule-Thomson (J-T) cooling system designed for the Probe Infrared Laser Spectrometer (PIRLS) proposed for the Huygens Titan Probe of the Cassini Saturn orbiter mission is presented. The cryogenic cooling requirements of the PIRLS instrument are listed, and the cooler system design including details of a J-T cryostat, cold head, and dewar design is described along with the results of a thermal modeling effort and lab cooler performance testing. It is shown that by using active feedback temperature control of the cold head in combination with the self-regulating action of the J-T cryostat, a temperature stability of less than 0.1 mK/min is achieved by the cooler weighting 1.8 kg.

Bard, Steven; Wu, J. J.; Trimble, Curt

1991-01-01

155

Ohm's Law, Fick's Law, Joule's Law, and Ground Water Flow  

SciTech Connect

Starting from the contributions of Ohm, Fick and Joule during the nineteenth century, an integral expression is derived for a steady-state groundwater flow system. In general, this integral statement gives expression to the fact that the steady-state groundwater system is characterized by two dependent variables, namely, flow geometry and fluid potential. As a consequence, solving the steady-state flow problem implies the finding of optimal conditions under which flow geometry and the distribution of potentials are compatible with each other, subject to the constraint of least action. With the availability of the digital computer and powerful graphics software, this perspective opens up possibilities of understanding the groundwater flow process without resorting to the traditional differential equation. Conceptual difficulties arise in extending the integral expression to a transient groundwater flow system. These difficulties suggest that the foundations of groundwater hydraulics deserve to be reexamined.

Narasimhan, T.N.

1999-02-01

156

Analysis of fluid flow in Joule-Thomson coolers coupled with infrared detector  

NASA Astrophysics Data System (ADS)

Joule-Thomson cooler have its unique advantages with respect to compact, light and low cost. Joule-Thomson coolers have been widely used in HgCdTe infrared detectors, InSb infrared detectors and InAs/GaSb superlattice infrared detectors. The performance of Joule-Thomson coolers is required to be improved with the development of higher mass and larger diameter focal plane infrared detectors. Joule-Thomson coolers use a limited supply of high pressure gas to support the cooling of infrared detectors. In order to maximize the usage time and minimize the cooling down time for a given volume of stored gas for Joule-Thomson coolers, it is important to study on fluid flow of Joule-Thomson coolers. Experiments were carried out to focus on the performance of Joule-Thomson coolers coupled with infrared detectors. The effect of ambient temperature, the state of supply gas pressure is considered. The relationship between volume rates and supply gas pressure was proved to fit some regulates while the other parameters are fixed. Moreover, the effects of ambient temperature are analyzed.

Du, Bingyan; Hu, Yin; Wang, Zhan; Li, Xiuqiang

2014-11-01

157

Final Report on the Joule-Scale Experimental Demonstration  

SciTech Connect

We describe the final results of the High Power Laser Pulse Recirculation project. We have developed and implementing a novel technique for picosecond, Joule-class laser pulse recirculation inside a passive cavity. The aim of this project was to develop technology compatible with increasing the efficiency of Compton based light sources by more than an order of magnitude. In year 1 of the project, we achieved a greater than 40 times average power enhancement of the mJ-scale laser pulses inside a passive cavity with internal focus. In year 2, we demonstrated recirculation of lasers pulses with energies up to 191 mJ at 532 nm, at a repetition rate of 10 Hz, and a pulse duration of 20 ps. In this high energy regime, we achieved up to 14 times average power enhancement inside the cavity. This enhancement factor is compatible with the new X-band based mono-energetic gamma-ray machine, Velociraptor, being constructed at LLNL. The demonstrated cavity enhancement is primarily limited by the poor spatial beam quality of the high power laser beam. We expect a nearly diffraction limited laser beam to achieve 40 times or better cavity enhancement, as demonstrated in low energy experiments in FY-07. The two primary obstacles to higher average brightness and conversion efficiency of laser pulse energy to gamma-rays are the relatively small Compton scattering cross-section and the typically low repetition rates of Joule-class interaction lasers (10 Hz). Only a small fraction (10{sup -10}) of the available laser photons is converted to gamma-rays, while the rest is discarded. To significantly reduce the average power requirements of the laser and increase the overall system efficiency, we can recirculate laser light for repeated interactions with electron bunches. Our pulse recirculation scheme is based on nonlinear frequency conversion, termed recirculation injection by nonlinear gating (RING), inside a passive cavity. The main objectives of the two year project were: (1) Validate the concept of RING pulse trapping and recirculation technique. Completed Sep. 07 (2) Develop cavity designs compatible with a laser-electron Compton light source. Completed January 08. (3) Demonstrate trapping and recirculation of laser pulses suitable for high brightness gamma-ray generation. Completed Aug. 08 Our project has established RING as a viable technology for enhancing Compton scattering based gamma-ray generation. With sufficient funding we can implement pulse recirculation on the next generation Mono-energetic Gamma-Ray machine under construction at LLNL.

Shverdin, M

2008-10-01

158

Mixed-refrigerant Joule-Thomson (MR JT) mini-cryocoolers  

NASA Astrophysics Data System (ADS)

This paper presents the progress in our ongoing research on Mixed-Refrigerant (MR) Joule-Thomson (JT) cryocoolers. The research begun by exploring different MRs and testing various compressors: oil-lubricated and oil-free, reciprocating and linear, custom-made and commercial. Closed-cycle JT cryocoolers benefit from the fact that the compressor might be located far from the cold-end and thus there are no moving parts, no vibrations, and no heat emission near the cold-end. As a consequence, the compressor may be located where there are no severe size limitations, its heat can be conveniently removed, and it can be easily maintained. However, in some applications there is still a demand for a small compressor to drive a JT cryocooler although it is located far from the cooled device. Recently, we have developed a miniature oil-free compressor for MR JT cryocoolers that weighs about 700 g and its volume equals about 300 cc. The cryocooler operates with a MR that contains Ne, N2, and Hydrocarbons. This MR has been widely investigated with different compressors and varying operating conditions and proved to be stable. The current research investigates the performances of MR JT mini-cryocooler operating with the MR mentioned above, driven with our miniature compressor, and a cold-finger prototype. A Dewar with heat load of about 230 mW is cooled to about 80 K at ambient temperatures between 0°C and 40°C. The experimental results obtained are stable and demonstrate the ability to control the cooling temperature by changing the rotation speed of the compressor.

Tzabar, Nir

2014-01-01

159

Joule-Thomson cryocooler with neon and nitrogen mixture using commercial air-conditioning compressors  

NASA Astrophysics Data System (ADS)

A 2-stage mixed refrigerant (MR) Joule-Thomson (JT) cryocooler was designed for cooling high temperature superconducting cable below 70 K. The low temperature cycle was to operate with neon-nitrogen mixture, and the required compression ratio was approximately 24 when the suction pressure was 100 kPa. The high compression ratio of 24, the low pressure of 100 kPa at compressor suction, and the working fluid with high heat of compression were challenging issues to existing typical compression systems. We developed an innovative compression system with commercial oil-lubricated air-conditioning compressors. They were 2-stage rotary compressors originally designed for R410Aand connected in series. The compressors were modified to accommodate effective intercooling at every stage to alleviate compressor overheating problem. Additionally, fine-grade three-stage oil filters, an adsorber, and driers were installed at the discharge line to avoid a potential clogging problem from oil mist and moisture at low temperature sections. The present compression system was specifically demonstrated with a neon-nitrogen MR JT cryocooler. The operating pressure ratio was able to meet the designed specifications, and the recorded no-load mini mum temperature was 63.5 K . Commercial air-conditioning compressors were successfully applied to the high-c ompression ratio MR JT cryocooler with adequate modification using off-the-shelf components.

Lee, Jisung; Oh, Haejin; Baek, Seungwhan; Lee, Cheonkyu; Jeong, Sangkwon

2014-01-01

160

Beam shaping in the MegaJoule laser project  

NASA Astrophysics Data System (ADS)

The LMJ (Laser MegaJoule) is dedicated to inertial confinement fusion. To perform this type of experiment, 160 square beams are frequency converted and focused onto a target filled with a deuterium tritium mixture. We propose to review how these beams are shaped along their propagation through the LMJ. Going upstream from the target to the laser source, specific optics has been designed to meet the beam shaping requirement. A focusing grating and a pseudorandom phase plate concentrate the energy onto the target. A deformable mirror controls and compensates the spatial phase defect occurring during the propagation through the main slab amplifiers. A liquid crystal cell shapes the beam in order to compensate the gain profile of the main amplifiers. It also protects the growth of damages that take place in the final optics of the chain. At last, a phase mirror generates a square flat top mode from a gaussian beam within a regenerative amplifier. All these optical components have one common principle: they control the phase of the spatial laser field.

Luce, Jacques

2011-10-01

161

On the Joule-Thomson integral inversion curves of quantum gases  

Microsoft Academic Search

The integral inversion curve (IIC) is the contour of all thermodynamic states (P,T) which exhibit a zero integral cooling under Joule-Thomson (isenthalpic) expansion from a pressure, P, down to ambient atmospheric pressure. This is an alternative and complementary presentation of the Joule-Thomson inversion phenomena. The traditional inversion curve is a differential one, namely, it distinguishes between states for which infinitesimal

B.-Z. Maytal; A. Shavit

1997-01-01

162

Clogging of Joule-Thomson Devices in Liquid Hydrogen Handling  

NASA Technical Reports Server (NTRS)

Experiments conducted at the NASA Glenn Research Center indicate that Joule-Thomson devices become clogged when transferring liquid hydrogen (LH2), operating at a temperature range from 20.5 to 24.4 K. Blockage does not exist under all test conditions but is found to be sensitive to the inlet temperature of the LH2. At a subcooled inlet temperature of 20.5 K blockage consistently appears but is dissipated when the fluid temperature is raised above 24.5 K. Clogging steadily reduced flow rate through the orifices, eventually resulting in complete blockage. This tendency poses a threat to spacecraft cryogenic propulsion systems that would utilize passive thermal control systems. We propose that this clogging is due to trace amounts of neon in the regular LH2 supply. Neon freezes at 24.5 K at one atmosphere pressure. It is postulated that between 20.5 and 24.5 K, neon remains in a meta-stable, supercooled liquid state. When impacting the face of an orifice, liquid neon droplets solidify and accumulate, blocking flow over time. The purpose of this test program was to definitively quantify the phenomena experimentally by obtaining direct visual evidence of orifice clogging by accretion from neon contaminates in the LH2 flow stream, utilizing state of the art imaging technology. Tests were conducted with LH2 flowing in the temperature range of 20.5 to 24.4 K. Additional imaging was also done at LH2 temperatures with no flow to verify clear view through the orifice.

Jurns, John M.; Lekki, John D.

2009-01-01

163

The Scientific Papers of James Prescott Joule 2 Volume Set  

NASA Astrophysics Data System (ADS)

Volume 1: Description of an electro-magnetic engine; Description of an electro-magnetic engine, with experiments; On the use of electro-magnets made of iron wire for the electro-magnetic engine; Investigations in magnetism and electro-magnetism; Investigations in magnetism and electro-magnetism; Description of an electro-magnetic engine; On electro-magnetic forces; On electro-magnetic forces; On electro-magnetic forces; Description of a new electro-magnet; On a new class of magnetic forces; On voltaic apparatus; On the production of heat by voltaic electricity; On the heat evolved by metallic conductors of electricity, and in the cells of a battery during electrolysis; On the electric origin of the heat of combustion; On the electrical origin of chemical heat; On Sir G. C. Haughton's experiments; On the heat evolved during the electrolysis of water; On the calorific effects of magneto-electricity, and on the mechanical value of heat; On the intermittent character of the voltaic current in certain cases of electrolysis; and on the intensities of various voltaic arrangements; On the changes of temperature produced by the rarefaction and condensation of air; On specific heat; On a new method for ascertaining the specific heat of bodies; Note on the employment of electrical currents for ascertaining the specific heat of bodies; On the mechanical equivalent of heat; On the existence of an equivalent relation between heat and the ordinary forms of mechanical power; On the heat disengaged in chemical combinations; On the effects of magnetism upon the dimensions of iron and steel bars; On matter, living force, and heat; On the mechanical equivalent of heat, as determined from the heat evolved by the function of fluids; On the theoretical velocity of sound; Expériences sur l'identité entre le calorique et la force méchanique. Détermination de l'équivalent par la chaleur dégagée pendant la friction du mercure; On shooting-stars; On the mechanical equivalent of heat, and on the constitution of elastic fluids; Some remarks on heat and the constitution of elastic fluids; On the mechanical equivalent of heat; On a remarkable appearance of lightning; On some amalgams; On the air-engine; Account of experiments with a powerful electro-magnet; On the economical production of mechanical effect from chemical forces; An account of some experiments with a large electro-magnet; Introductory research on the induction of magnetism by electric currents; On the fusion of metals by voltaic electricity; Note on Dalton's determination of the expansion of air by heat; On the utilization of the sewage of London and other large towns; Notice of experiments on the heat developed by friction in air; On the intensity of light during the recent solar eclipse; On an improved galvanometer; On the thermo-electricity of ferruginous metals, and on the thermal effects of stretching solid bodies; On the thermal effects of longitudinal compression of solids, with an investigation on the alterations of temperature accompanying changes of pressure in fluids; On some thermo-dynamic properties of solids; On the thermal effects of compressing fluids; On a method of testing the strength of steam-boilers; Experiments on the total heat of steam; Experiments on the passage of air through pipes and apertures in thin plates; On some amalgams; On the probable cause of electric storms; On the surface-condensation of steam; Notice of a compressing air-pump; Note on a mirage at Douglas; On a sensitive barometer; On a sensitive thermometer; Note on the meteor of February 6th, 1818; On a method of hardening steel wires for magnetic needles; On an instrument for showing rapid changes in magnetic declination; Determination of the dynamical equivalent of heat from the thermal effects of electric currents; Observations on the alteration of the freezing-point in thermometers; On a new

Prescott Joule, James

2011-03-01

164

Effects of environmental temperature on performance of the Joule-Thomson refrigerator  

NASA Astrophysics Data System (ADS)

Miniature Joule-Thomson refrigerators have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. Typical performance factors of the Joule-Thomson refrigerator are cool-down time, temperature of the cold end, running time and gas consumption. Those depend on operating conditions such as the pressure of the gas, thermal environment and etc.. In this study, experimental study of a miniature Joule- Thomson refrigerator with the gas pressure up to 12 MPa were performed to investigate the effects of the thermal environment (-40 ~ 50 °C). In experiments, to obtain the information of cool-down time, gas consumption and etc., the temperature of the cold end, mass flow rate and pressure of the argon gas are simultaneously measured. The Joule-Thomson refrigerator in cold thermal environment has rapid cool-down characteristics and small gas consumption. In the cold environmental condition, the Joule-Thomson refrigerator has high mass flow rate during cool-down process and in steady state.

Hong, Yong-Ju; Kim, Hyobong; Park, Seong-Je

2012-06-01

165

Integrated Heat Switch/Oxide Sorption Compressor  

NASA Technical Reports Server (NTRS)

Thermally-driven, nonmechanical compressor uses container filled with compressed praseodymium cerium oxide powder (PrCeOx) to provide high-pressure flow of oxygen gas for driving closed-cycle Joule-Thomson-expansion refrigeration unit. Integrated heat switch/oxide sorption compressor has no moving parts except check valves, which control flow of oxygen gas between compressor and closed-cycle Joule-Thomson refrigeration system. Oxygen expelled from sorbent at high pressure by evacuating heat-switch gap and turning on heater.

Bard, Steven

1989-01-01

166

Experimental Investigation for 100-Joule-class TEA CO2 Laser and Gas Interaction  

NASA Astrophysics Data System (ADS)

Impulse coupling coefficient Cm is one of the most important performance parameters in laser propulsion. Cm is the impulse increment of lightcraft that per joule laser beam energy acts on. The TEA CO2 laser, whose single pulse energy is 100-Joule-class and wavelength is 10.6?m, is adopted by experimental research. In experimental environment cabin, the parabolic lightcraft is fixed on impact pendulum. Using Air, N2, He, CO2, N2-He and N2-CO2, different Cm is obtained. Experimental results indicate that Cm of the mixed gas is improved through changing gas component ratio.

Dou, Zhiguo; Yao, Honglin; Wang, Jun; Wen, Ming; Wang, Peng; Yang, Jan; Li, Chong

2006-05-01

167

Binary mixed-refrigerants for steady cooling temperatures between 80 K and 150 K with Joule-Thomson cryocoolers  

NASA Astrophysics Data System (ADS)

Joule-Thomson (JT) cryocoolers operating with pure gases attain vapor-liquid equilibrium in the evaporator and yield a steady cooling temperature which depends solely on the pressure. Mixed gases often substitute the pure gases as the working fluid in order to allow lower pressure ratios and improved coefficient of performance; however, mixed refrigerants are known for their cooling temperature dependence on the ambient temperature and heat load. It is possible to control the cooling temperature via the compressor operating parameters, heating device at the evaporator, bypass ports for the fluid, and more. The present research aims to achieve a steady cooling temperature with mixed refrigerants in a manner similar to pure refrigerants; meaning, having enough phases to leave a single degree of freedom of the fluid thermodynamic state. Thus, by stabilizing the pressure a stable temperature is attained. The current study focuses on binary mixtures since they can be analytically investigated in a more convenient manner relative to multi-component mixtures. Nitrogen-ethane and nitrogen-propane mixtures are considered based on former research conclusions. The present research includes an analytical method for calculating the cooling temperature, a numerical method for calculating the cooling power of the JT cryocooler in order to evaluate whether the cooling temperature is feasible, and experimental data are presented to verify some of the calculated results.

Tzabar, N.

2014-11-01

168

Direct observation of nanoscale Peltier and Joule effects at metal-insulator domain walls in vanadium dioxide nanobeams.  

PubMed

The metal to insulator transition (MIT) of strongly correlated materials is subject to strong lattice coupling, which brings about the unique one-dimensional alignment of metal-insulator (M-I) domains along nanowires or nanobeams. Many studies have investigated the effects of stress on the MIT and hence the phase boundary, but few have directly examined the temperature profile across the metal-insulating interface. Here, we use thermoreflectance microscopy to create two-dimensional temperature maps of single-crystalline VO2 nanobeams under external bias in the phase coexisting regime. We directly observe highly localized alternating Peltier heating and cooling as well as Joule heating concentrated at the M-I domain boundaries, indicating the significance of the domain walls and band offsets. Utilizing the thermoreflectance technique, we are able to elucidate strain accumulation along the nanobeam and distinguish between two insulating phases of VO2 through detection of the opposite polarity of their respective thermoreflectance coefficients. Microelasticity theory was employed to predict favorable domain wall configurations, confirming the monoclinic phase identification. PMID:24735496

Favaloro, Tela; Suh, Joonki; Vermeersch, Bjorn; Liu, Kai; Gu, Yijia; Chen, Long-Qing; Wang, Kevin X; Wu, Junqiao; Shakouri, Ali

2014-05-14

169

Some Joules Are More Precious Than Others: Managing Renewable Energy in the Datacenter  

E-print Network

to data mining. Increasingly, these datacenters use renewable energy from wind tur- bines or solar panels is an electrical joule converted from solar/wind energy. Permission to make digital or hard copies of all or part on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires

Shen, Kai

170

Mechanisms of Impulse Breakdown in Liquid: The Role of Joule Heating and Formation of Gas Cavities  

Microsoft Academic Search

The impulse dielectric behavior of insulating liquids is of significant interest for researchers and engineers working in the field of design, construction, and operation of pulsed power systems. Analysis of the literature data on transformer oils shows that potentially there are several different physical processes that could be responsible for dielectric breakdown by submicrosecond and microsecond impulses. While for short

Vladimir M. Atrazhev; Vladimir S. Vorob'ev; Igor V. Timoshkin; Martin J. Given; Scott J. MacGregor

2010-01-01

171

Effect of filler dispersion degree on the Joule heating stimulated recovery behaviour of nanocomposites  

Microsoft Academic Search

Composites based on highly branched ethylene-1-octene copolymer (EOC) and carbon black (CB) with different dispersion degree\\u000a of CB were prepared. The method of the online measured electrical conductance\\/resistance was used to monitor the change of\\u000a the electrical conductance\\/resistance of the composites during the preparation processes, i.e. mixing and cross-linking. It\\u000a was found that the kinetics of thermally stimulated shape-memory recovery

H. H. Le; I. Kolesov; Z. Ali; M. Uthardt; O. Osazuwa; S. Ilisch; H.-J. Radusch

2010-01-01

172

Billet Heating with the Homopolar Generator  

E-print Network

BILLET HEATING WITH THE HOMOPOLAR GENERATOR William F. Weldon and Robert E. Keith Center for Electromechanics The University of Texas at Austin and James M. Weldon Astec Industries, Inc. Austin, Texas ABSTRACT Forging bi... velocity is limited by brush life considerations to 200 m/s (v = Rw = 200 m/s) so that E = 2.461 x 10 8 R 2 t Homopo1ar generators storing from a few ki10jou1es (10 3 joules) to several gigajou1es (10 9 joules) have been designed. UT-CEM has a 5 MJ...

Weldon, W. F.; Keith, R. E.; Weldon, J. M.

1980-01-01

173

Acquisition and correlation of cryogenic nitrogen mass flow data through a multiple orifice Joule-Thomson device  

NASA Technical Reports Server (NTRS)

Liquid nitrogen mass flow rate, pressure drop, and temperature drop data were obtained for a series of multiple orifice Joule-Thomson devices, known as Visco Jets, over a wide range of flow resistance. The test rig used to acquire the data was designed to minimize heat transfer so that fluid expansion through the Visco Jets would be isenthalpic. The data include a range of fluid inlet pressures from 30 to 60 psia, fluid inlet temperatures from 118 to 164 R, outlet pressures from 2.8 to 55.8 psia, outlet temperatures from 117 to 162 R and flow rate from 0.04 to 4.0 lbm/hr of nitrogen. A flow rate equation supplied by the manufacturer was found to accurately predict single-phase (noncavitating) liquid nitrogen flow through the Visco Jets. For cavitating flow, the manufacturer's equation was found to be inaccurate. Greatly improved results were achieved with a modified version of the single-phase equation. The modification consists of a multiplication factor to the manufacturer's equation equal to one minus the downstream quality on an isenthalpic expansion of the fluid across the Visco Jet. For a range of flow resistances represented by Visco Jet Lohm ratings between 17,600 and 80,000, 100 percent of the single-phase data and 85 percent of the two-phase data fall within + or - 10 percent of predicted values.

Papell, S. Stephen; Saiyed, Naseem H.; Nyland, Ted W.

1990-01-01

174

Investigation of neon-nitrogen mixed refrigerant Joule-Thomson cryocooler operating below 70 K with precooling at 100 K  

NASA Astrophysics Data System (ADS)

There has been two-stage mixed refrigerant (MR) Joule-Thomson (JT) refrigeration cycle suggested for cooling high temperature superconductor (HTS) electric power cable below 70 K. As the continuation effort of realizing the actual system, we fabricated and tested a small scale neon and nitrogen MR JT cryocooler to investigate the refrigeration characteristics and performance. The compression system of the refrigeration circuit was accomplished by modifying commercially available air-conditioning rotary compressors. Compressors stably operated at the maximum compression ratio of 31 when the suction pressure was 77 kPa. The achieved lowest temperature was 63.6 K when the heating load was 35.9 W. The measured Carnot efficiency of the present system was 6.5% which was lower than that of the designed goal of 17.4%. The low efficiency of compressor (34.5%), and the pressure drop at the compressor suction were the main reasons for this efficiency degradation. The feasibility and usefulness of neon and nitrogen MR JT refrigeration cycle was validated that the achieved minimum temperature was 63.6 K even though the pressure after the expansion was maintained by 130 kPa. The comparison between the measurement and calculation showed that each stream temperature of refrigeration cycle were predictable within 3% error by Peng-Robinson equation of state (EOS).

Lee, Jisung; Oh, Haejin; Jeong, Sangkwon

2014-05-01

175

Joule-Thomson inversion curves and related coefficients for several simple fluids  

NASA Technical Reports Server (NTRS)

The equations of state (PVT relations) for methane, oxygen, argon, carbon dioxide, carbon monoxide, neon, hydrogen, and helium were used to establish Joule-Thomson inversion curves for each fluid. The principle of corresponding states was applied to the inversion curves, and a generalized inversion curve for fluids with small acentric factors was developed. The quantum fluids (neon, hydrogen, and helium) were excluded from the generalization, but available data for the fluids xenon and krypton were included. The critical isenthalpic Joule-Thomson coefficient mu sub c was determined; and a simplified approximation mu sub c approximates T sub c divided by 6P sub c was found adequate, where T sub c and P sub c are the temperature and pressure at the thermodynamic critical point. The maximum inversion temperatures were obtained from the second virial coefficient (maximum (B/T)).

Hendricks, R. C.; Peller, I. C.; Baron, A. K.

1972-01-01

176

Quantum Joule-Thomson Effect in a Saturated Homogeneous Bose Gas  

NASA Astrophysics Data System (ADS)

We study the thermodynamics of Bose-Einstein condensation in a weakly interacting quasihomogeneous atomic gas, prepared in an optical-box trap. We characterize the critical point for condensation and observe saturation of the thermal component in a partially condensed cloud, in agreement with Einstein's textbook picture of a purely statistical phase transition. Finally, we observe the quantum Joule-Thomson effect, namely isoenthalpic cooling of an (essentially) ideal gas. In our experiments this cooling occurs spontaneously, due to energy-independent collisions with the background gas in the vacuum chamber. We extract a Joule-Thomson coefficient ?JT>109 K /bar, about 10 orders of magnitude larger than observed in classical gases.

Schmidutz, Tobias F.; Gotlibovych, Igor; Gaunt, Alexander L.; Smith, Robert P.; Navon, Nir; Hadzibabic, Zoran

2014-01-01

177

Quantum Joule-Thomson effect in a saturated homogeneous Bose gas.  

PubMed

We study the thermodynamics of Bose-Einstein condensation in a weakly interacting quasihomogeneous atomic gas, prepared in an optical-box trap. We characterize the critical point for condensation and observe saturation of the thermal component in a partially condensed cloud, in agreement with Einstein's textbook picture of a purely statistical phase transition. Finally, we observe the quantum Joule-Thomson effect, namely isoenthalpic cooling of an (essentially) ideal gas. In our experiments this cooling occurs spontaneously, due to energy-independent collisions with the background gas in the vacuum chamber. We extract a Joule-Thomson coefficient ?JT>10(9)??K/bar, about 10 orders of magnitude larger than observed in classical gases. PMID:24580421

Schmidutz, Tobias F; Gotlibovych, Igor; Gaunt, Alexander L; Smith, Robert P; Navon, Nir; Hadzibabic, Zoran

2014-01-31

178

The development of a proff of principle superfluid Joule-Thomson refrigerator for cooling below 1 Kelvin  

E-print Network

A new type of sub-Kelvin refrigerator, the superfluid Joule-Thomson refrigerator, has been developed and its performance has been experimentally verified. This refrigerator uses a liquid superfluid mixture of He and 4He ...

Miller, Franklin K., 1970-

2005-01-01

179

Hampson’s type cryocoolers with distributed Joule-Thomson effect for mixed refrigerants closed cycle  

NASA Astrophysics Data System (ADS)

Most previous studies on Joule-Thomson cryocoolers of mixed refrigerants in a closed cycle focus on the Linde kind recuperator. The present study focuses on four constructions of Hampson’s kind miniature Joule-Thomson cryocoolers based on finned capillary tubes. The frictional pressure drop along the tubes plays the role of distributed Joule-Thomson expansion so that an additional orifice or any throttle at the cold end is eliminated. The high pressure tube is a throttle and a channel of recuperation at the same time. These coolers are tested within two closed cycle systems of different compressors and different compositions of mixed coolants. All tests were driven by the same level of discharge pressure (2.9 MPa) while the associated suction pressures and the associated reached temperatures are dependent on each particular cryocooler and on the closed cycle system. The mixture of higher specific cooling capacity cannot reach temperatures below 80 K when driven by the smaller compressor. The other mixture of lower specific cooling capacity driven by the larger compressor reaches lower temperatures. The examined parameters are the cooldown period and the reachable temperatures by each cryocooler.

Maytal, Ben-Zion

2014-05-01

180

Thermophoretic hydromagnetic dissipative heat and mass transfer with lateral mass flux, heat source, Ohmic heating and thermal conductivity effects: Network simulation numerical study  

Microsoft Academic Search

A two-dimensional mathematical model is presented for the laminar heat and mass transfer of an electrically-conducting, heat generating\\/absorbing fluid past a perforated horizontal surface in the presence of viscous and Joule (Ohmic) heating. The Talbot–Cheng–Scheffer–Willis formulation (1980) is used to introduce a thermophoretic coefficient into the concentration boundary layer equation. The governing partial differential equations are non-dimensionalized and transformed into

Joaquín Zueco; O. Anwar Bég; H. S. Takhar; V. R. Prasad

2009-01-01

181

Fast and uniform heating of Cu microwires using electrical current  

NASA Astrophysics Data System (ADS)

A fast and uniform heat treatment of 25-µm-thick Cu microwires was realized with Joule heating. To control the thermal boundary conditions around a wire, a constant direct current was supplied to the wire under vacuum conditions using current probes with sufficient heat capacity, and a uniform temperature distribution was realized in the wire. The grain size of the wire increased with the time for which current was supplied, and reached saturation within 10 s.

Tohmyoh, Hironori; Matsudo, Yohei

2015-04-01

182

GEM-CEDAR Study of Ionospheric Energy Input and Joule Dissipation  

NASA Technical Reports Server (NTRS)

We are studying ionospheric model performance for six events selected for the GEM-CEDAR modeling challenge. DMSP measurements of electric and magnetic fields are converted into Poynting Flux values that estimate the energy input into the ionosphere. Models generate rates of ionospheric Joule dissipation that are compared to the energy influx. Models include the ionosphere models CTIPe and Weimer and the ionospheric electrodynamic outputs of global magnetosphere models SWMF, LFM, and OpenGGCM. This study evaluates the model performance in terms of overall balance between energy influx and dissipation and tests the assumption that Joule dissipation occurs locally where electromagnetic energy flux enters the ionosphere. We present results in terms of skill scores now commonly used in metrics and validation studies and we can measure the agreement in terms of temporal and spatial distribution of dissipation (i.e, location of auroral activity) along passes of the DMSP satellite with the passes' proximity to the magnetic pole and solar wind activity level.

Rastaetter, Lutz; Kuznetsova, Maria M.; Shim, Jasoon

2012-01-01

183

Measurements of Plasma Density in a Fast and Compact Plasma Focus Operating at Hundreds of Joules  

SciTech Connect

It is known that there are plasma parameters that remain relatively constant for plasma focus facilities operating in a wide range of de energy, from 1kJ to 1MJ, such as: electron density, temperature and plasma energy density. Particularly the electron density is of the order of 1025m-3. Recently the experimental studies in plasma focus has been extended to devices operating under 1kJ, in the range of hundreds and tens of joules. In this work an optical refractive system was implemented in order to measure the electron density in a plasma focus devices of hundred of joules, PF-400J (880 nF, 30 kV, 120 kA, 400 J, 300 ns time to peak current, dI/dt{approx}4x1011 A/s. The plasma discharge was synchronized with a pulsed Nd-YAG laser ({approx}6ns FWHM at 532nm) in order to obtain optical diagnostics as interferometry and Schlieren. An electron density of (0.9{+-}0.25)x1025m-3 was obtained at the axis of the plasma column close to the pinch time. This value is of the same order that the obtained in devices oparating in the energy range of 1kJ to 1MJ.

Pavez, Cristian [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Universidad de Concepcion, Facultad de Ciencias, Departamento de Fisica, Concepcion (Chile); Silva, Patricio; Moreno, Jose; Soto, Leopoldo [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile)

2006-12-04

184

Plasma density cavitation due to inertial Alfvén wave heating  

Microsoft Academic Search

It is found that the differential Joule heating of the electrons in the inertial Alfvén wave fields can be responsible for the fine scale density cavitations that are observed by the FREJA and FAST (Fast Auroral SnapshoT) spacecrafts in the Earth's auroral plasma.

P. K. Shukla; L. Stenflo

1999-01-01

185

Self-heating in normal metals and superconductors  

Microsoft Academic Search

This review is devoted to the physics of current-carrying superconductors and normal metals having two or more stable states sustained by Joule self-heating. The creation, propagation, and localization of electrothermal domains and switching waves leading to the transition from one stable state to another in uniform and nonuniform samples are treated in detail. The connection between thermal bistability and hysteresis,

A. V. Gurevich; R. G. Mints

1987-01-01

186

Numerical simulation of the laser compression and heating of simple shell-targets  

Microsoft Academic Search

The paper presents results of numerical experiments on the heating and compression of a spherical hydrogen pellet by laser pulses with energies of several hundred Joules in a laser fusion simulation. Attention is given to the effects of the preheating of the central part of the target by fast electrons, of constraints on the heat flux, of variations in the

S. I. Anisimov; M. F. Ivanov; N. A. Inogamov; P. P. Pashinin; A. M. Prokhorov

1977-01-01

187

A Laser Speckle Method for Measuring Displacement Field. Application to Resistance Heating Tensile Test on Steel  

E-print Network

, at high temperature and in the semi-solid state. Actually, there is only few data for constitutive laws in the semi-solid state. Before applying the loading cycle, the sample is directly heated by Joule effect. A thermocouple is welded in the middle of the specimen. During the heating and loading phases of the test

Paris-Sud XI, Université de

188

Overview of the ARGOS X-ray framing camera for Laser MegaJoule  

SciTech Connect

Commissariat à l’Énergie Atomique et aux Énergies Alternatives has developed the ARGOS X-ray framing camera to perform two-dimensional, high-timing resolution imaging of an imploding target on the French high-power laser facility Laser MegaJoule. The main features of this camera are: a microchannel plate gated X-ray detector, a spring-loaded CCD camera that maintains proximity focus in any orientation, and electronics packages that provide remotely-selectable high-voltages to modify the exposure-time of the camera. These components are integrated into an “air-box” that protects them from the harsh environmental conditions. A miniaturized X-ray generator is also part of the device for in situ self-testing purposes.

Trosseille, C., E-mail: clement.trosseille@cea.fr; Aubert, D.; Auger, L.; Bazzoli, S.; Brunel, P.; Burillo, M.; Chollet, C.; Jasmin, S.; Maruenda, P.; Moreau, I.; Oudot, G.; Raimbourg, J.; Soullié, G.; Stemmler, P.; Zuber, C. [CEA, DAM, DIF, F-91297 Arpajon (France); Beck, T. [CEA, DEN, CADARACHE, F-13108 St Paul lez Durance (France); Gazave, J. [CEA, DAM, CESTA, F-33116 Le Barp (France)

2014-11-15

189

Soft X-Ray Emission and Charged Particles Beams from a Plasma Focus of Hundreds Joules  

SciTech Connect

In a new stage of characterization of our plasma focus devices of hundred and tens of joules (PF-400J and PF-50J), preliminary series of measurements on soft X-ray and ion beams have been performed in the device PF-400J (176-539 J, 880 nF, T/4 {approx}300 ns). The device was operated in hydrogen to 7 mbar of pressure . The temporal and spatial X-ray characteristics are investigated by means filtered PIN diodes and a multipinhole camera. Graphite collectors, operating in the bias ion collector mode, are used to estimate the characteristic ion energy using the time flight across the probe array. The time of the ion beam emission to be correlated with plasma emission events associated with the soft X-ray pulses detected by the probes. Temporal correlations between soft X-ray signals and ion beams are performed.

Silva, Patricio; Moreno, Jose; Soto, Leopoldo [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Pavez, Cristian [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Universidad de Concepcion, Facultad de Ciencias, Departamento de Fisica, Concepcion (Chile); Arancibia, Jaime [Universidad de Chile, Facultad de Ciencias, Departamento de Fisica, Santiago (Chile)

2006-12-04

190

Overview of the ARGOS X-ray framing camera for Laser MegaJoule.  

PubMed

Commissariat à l'Énergie Atomique et aux Énergies Alternatives has developed the ARGOS X-ray framing camera to perform two-dimensional, high-timing resolution imaging of an imploding target on the French high-power laser facility Laser MegaJoule. The main features of this camera are: a microchannel plate gated X-ray detector, a spring-loaded CCD camera that maintains proximity focus in any orientation, and electronics packages that provide remotely-selectable high-voltages to modify the exposure-time of the camera. These components are integrated into an "air-box" that protects them from the harsh environmental conditions. A miniaturized X-ray generator is also part of the device for in situ self-testing purposes. PMID:25430196

Trosseille, C; Aubert, D; Auger, L; Bazzoli, S; Beck, T; Brunel, P; Burillo, M; Chollet, C; Gazave, J; Jasmin, S; Maruenda, P; Moreau, I; Oudot, G; Raimbourg, J; Soullié, G; Stemmler, P; Zuber, C

2014-11-01

191

Evaluation of metal hydride compressors for applications in Joule-Thomson cryocoolers  

NASA Astrophysics Data System (ADS)

The Joule-Thomson expansion of hydrogen gas offers the potential for efficient and reliable cryocoolers to produce temperatures between 10 and 50 K. A critical component of the development of these devices is the metal-hydride storage bed that provides a nonmechanical method to compress the hydrogen gas via the reversible absorption by the appropriate metals or alloys. The influences of the thermophysical properties of these metal hydrides as well as compressor design constraints on the performance potentials of hydrogen sorption refrigerators are examined. A thermodynamics model is used to calculate the impact of operational parameters such as input/output pressure ratios and bed temperature on system efficiency. Detailed comparisons are reported for a compressor which utilizes vanadium metal as the sorbent for either hydrogen or deuterium where the unusually large isotope differences between VH(x) and VD(x) are considered.

Bowman, R. C., Jr.; Freeman, B. D.; Phillips, J. R.

192

Direct-drive shock-ignition for the Laser MégaJoule  

NASA Astrophysics Data System (ADS)

We present a review of direct-drive shock ignition studies done as an alternative for the Laser MégaJoule (LMJ). One and two dimensional systematic analyses of HiPER-like shock-ignited target designs are performed for the fuel assembly irradiation uniformity using the whole LMJ configuration or a part of the facility, and for the uniformity of the ignitor spike. High-gain shock-ignition is shown to be possible with intensity of each quad less than 1015 W/cm2 but low modes asymmetries displace the power required in the ignitor spike towards higher powers. Shock-ignition of Direct-Drive Double-Shell non-cryogenic targets is also addressed.

Canaud, B.; Brandon, V.; Laffite, S.; Temporal, M.; Ramis, R.

2013-11-01

193

Influence of the Thomson effect on the pulse heating of high-current electrical contacts  

NASA Astrophysics Data System (ADS)

Pulse heating of high-current contacts is notable for the presence of considerable temperature gradients in the contact area, which cause the Thomson effect—the appearance of thermoelectric currents. The amount of this effect against conventional Joule heat release is quantitatively estimated. Pulse heating of electrical contacts is numerically simulated with the use of the Comsol program package. It is demonstrated that thermoelectric currents make a negligible contribution to heating in the case of copper contacts.

Merkushev, A. G.; Pavleino, M. A.; Pavleino, O. M.; Pavlov, V. A.

2014-09-01

194

Two-Phase Cryogenic Heat Exchanger for the Thermodynamic Vent System  

NASA Technical Reports Server (NTRS)

A two-phase cryogenic heat exchanger for a thermodynamic vent system was designed and analyzed, and the predicted performance was compared with test results. A method for determining the required size of the Joule-Thomson device was also developed. Numerous sensitivity studies were performed to show that the design was robust and possessed a comfortable capacity margin. The comparison with the test results showed very similar heat extraction performance for similar inlet conditions. It was also shown that estimates for Joule- Thomson device flow rates and exit quality can vary significantly and these need to be accommodated for with a robust system design.

Christie, Robert J.

2011-01-01

195

February 20, 2014 14:4 WSPC -Proceedings Trim Size: 9.75in x 6.5in proceedingBru-Pedra Microscopic Foundations of Ohm and Joule's Laws The Relevance of  

E-print Network

Microscopic Foundations of Ohm and Joule's Laws ­ The Relevance of Thermodynamics J.-B. Bru and W. de Siqueira of quantum mechanical microscopic models, Green­Kubo relations. Keywords: Ohm's law, Joule's law.1. The Genesis of Ohm and Joule's laws G.S. Ohm was born in 1789 in Erlangen and came from a modest background

196

A simple study of gas heating effect for argon lamp  

Microsoft Academic Search

The electrical properties of an argon glow discharge are simulated by a one-dimensional fluid model. Plane-parallel electrodes place at a distance of 1.5 cm are sustained with direct current (dc) voltage (0?heat transport equation in the Joule heating approximation and without including the reflected particles effect. Using the empirical Townsend ionisation

S. Medina; K. Yanallah; L. Mehdaoui; A. Belasri; T. Baba-Hamed

2005-01-01

197

Numerical analysis of the direct drive illumination uniformity for the Laser MegaJoule facility  

NASA Astrophysics Data System (ADS)

The illumination uniformity provided during the initial imprinting phase of the laser foot pulse in a direct drive scenario at the Laser MegaJoule facility has been analyzed. This study analyzes the quality of the illumination of a spherical capsule and concerns the uniformity of the first shock generate in the absorber of an Inertial Confinement Fusion capsule. Four configurations making use of all or some of the 80 laser beams organized in the 20 quads of the cones at 49° and 131° with respect to the polar axis have been considered in order to assemble the foot pulse. Elliptical and circular super-gaussian laser intensity profiles taking into account beam-to-beam power imbalance (10%), pointing error (50 ?m), and target positioning (20 ?m) have been considered. It has been found that the use of the Polar Direct Drive technique can in some cases reduce the irradiation non-uniformity by a factor as high as 50%. In all cases, elliptical profile provides better results in comparison with the circular one and it is shown that the minimum of the non-uniformity is also a function of the capsule radius.

Temporal, M.; Canaud, B.; Garbett, W. J.; Ramis, R.

2014-01-01

198

Numerical analysis of the direct drive illumination uniformity for the Laser MegaJoule facility  

SciTech Connect

The illumination uniformity provided during the initial imprinting phase of the laser foot pulse in a direct drive scenario at the Laser MegaJoule facility has been analyzed. This study analyzes the quality of the illumination of a spherical capsule and concerns the uniformity of the first shock generate in the absorber of an Inertial Confinement Fusion capsule. Four configurations making use of all or some of the 80 laser beams organized in the 20 quads of the cones at 49° and 131° with respect to the polar axis have been considered in order to assemble the foot pulse. Elliptical and circular super-gaussian laser intensity profiles taking into account beam-to-beam power imbalance (10%), pointing error (50??m), and target positioning (20??m) have been considered. It has been found that the use of the Polar Direct Drive technique can in some cases reduce the irradiation non-uniformity by a factor as high as 50%. In all cases, elliptical profile provides better results in comparison with the circular one and it is shown that the minimum of the non-uniformity is also a function of the capsule radius.

Temporal, M., E-mail: mauro.temporal@hotmail.com [Centre de Mathématiques et de Leurs Applications, ENS Cachan and CNRS, 61 Av. du President Wilson, F-94235 Cachan Cedex (France); Canaud, B. [CEA, DIF, F-91297 Arpajon Cedex (France)] [CEA, DIF, F-91297 Arpajon Cedex (France); Garbett, W. J. [AWE plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom)] [AWE plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Ramis, R. [ETSI Aeronáuticos, Universidad Politécnica de Madrid, 28040 Madrid (Spain)] [ETSI Aeronáuticos, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

2014-01-15

199

Statistical spatio-temporal properties of the Laser MegaJoule speckle  

SciTech Connect

This paper investigates a statistical model to describe the spatial and temporal properties of hot spots generated by the superimposition of multiple laser beams. In the context of the Laser MegaJoule design, we introduce the formula for contrasts, trajectories and velocities of the speckle pattern. Single bundle of four beams, two-cones and three-cones configurations are considered. Statistical properties of the speckle in the zone where all the beams overlap are studied with different configurations of polarizations. These properties are shown to be very different from the case of one single bundle of four beams. The configuration of polarization has only a slight effect in the two-cones or three cones configuration. Indeed, the impact of the double polarization smoothing is reduced in the area in which all the beams overlap, while it is much more significant when they split. Moreover, the size of the hot-spots decreases as the number of laser beams increases, but we show that their velocity decreases. As a matter of fact, the maximal velocity of hot spots is found to be only about 10{sup -5} of the velocity of light and the integrated contrast is about 15% when the beams overlap.

Le Cain, A.; Sajer, J. M. [CEA, DAM, CESTA, BP 2, F-33114 Le Barp (France); Riazuelo, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

2012-10-15

200

Study of organic contamination induced by outgassing materials. Application to the Laser MégaJoule optics  

NASA Astrophysics Data System (ADS)

Organic contamination may decrease the targeted performances of coated surfaces. To study the contamination induced by surrounding materials, a method using a thermal extractor is presented in the first part of this work. Besides its normal operation (analyses of outgassing compounds from a material), this device is used in an original way to contaminate and decontaminate samples. Efficiency of contamination and decontamination protocols are assessed by automated thermal desorption and gas chromatography coupled with mass spectrometry and by secondary ion mass spectrometry coupled with a time of flight mass analyzer. This enables to study the contamination induced by a bulk material outgassing and to take in consideration the possible competition between outgassed species. This method is then applied to investigate contamination of Laser MégaJoule sol-gel coated optics by a retractable sheath. The impact of the temperature on the outgassing of the sheath has been highlighted. Increasing temperature from 30 to 50 °C enables the outgassing of organophosphorous compounds and increases the outgassing of oxygenated compounds and phthalates. Chemical analyses of contaminated optics have highlighted affinities between the sol-gel coating and phthalates and organophosphorous, and low affinities with aromatics and terpens. Finally, samples with increasing levels of contamination have been realized. However a saturation phenomenon is observed at 90 ng cm-2.

Favrat, O.; Mangote, B.; Tovena-Pécault, I.; Néauport, J.

2014-02-01

201

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler  

NASA Astrophysics Data System (ADS)

A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.

Ardhapurkar, P. M.; Sridharan, Arunkumar; Atrey, M. D.

2014-01-01

202

Investigation of pressure drop in capillary tube for mixed refrigerant Joule-Thomson cryocooler  

SciTech Connect

A capillary tube is commonly used in small capacity refrigeration and air-conditioning systems. It is also a preferred expansion device in mixed refrigerant Joule-Thomson (MR J-T) cryocoolers, since it is inexpensive and simple in configuration. However, the flow inside a capillary tube is complex, since flashing process that occurs in case of refrigeration and air-conditioning systems is metastable. A mixture of refrigerants such as nitrogen, methane, ethane, propane and iso-butane expands below its inversion temperature in the capillary tube of MR J-T cryocooler and reaches cryogenic temperature. The mass flow rate of refrigerant mixture circulating through capillary tube depends on the pressure difference across it. There are many empirical correlations which predict pressure drop across the capillary tube. However, they have not been tested for refrigerant mixtures and for operating conditions of the cryocooler. The present paper assesses the existing empirical correlations for predicting overall pressure drop across the capillary tube for the MR J-T cryocooler. The empirical correlations refer to homogeneous as well as separated flow models. Experiments are carried out to measure the overall pressure drop across the capillary tube for the cooler. Three different compositions of refrigerant mixture are used to study the pressure drop variations. The predicted overall pressure drop across the capillary tube is compared with the experimentally obtained value. The predictions obtained using homogeneous model show better match with the experimental results compared to separated flow models.

Ardhapurkar, P. M. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 India and S. S. G. M. College of Engineering Shegaon, MS 444 203 (India); Sridharan, Arunkumar; Atrey, M. D. [Mechanical Engineering Department, Indian Institute of Technology Bombay, Mumbai, MS 400 076 (India)

2014-01-29

203

FY 2009 Annual Report of Joule Software Metric SC GG 3.1\\/2.5.2, Improve Computational Science Capabilities  

Microsoft Academic Search

The Joule Software Metric for Computational Effectiveness is established by Public Authorizations PL 95-91, Department of Energy Organization Act, and PL 103-62, Government Performance and Results Act. The U.S. Office of Management and Budget (OMB) oversees the preparation and administration of the President s budget; evaluates the effectiveness of agency programs, policies, and procedures; assesses competing funding demands across agencies;

Douglas B Kothe; Kenneth J Roche; Ricky A Kendall

2010-01-01

204

Acceleration of solar wind in polar coronal holes by induction heating  

Microsoft Academic Search

The universal induction heating mechanism supplying with the energy all the processes of coronal heating and the solar wind acceleration is developed. The observed relative 'trembling' of photospheric super-large scale magnetic fields with quasi-periods of 1-4 days amounts 30-40 percent in amplitude. The inductive electric field appears in the corona. The electric currents cause the Joule dissipation. The uneven heating

A. D. Chertkov; A. E. Shkrebets; Yu. V. Arkhipov; V. A. Soldatov

1995-01-01

205

Turbulent resistive heating of solar coronal arches  

NASA Technical Reports Server (NTRS)

The possibility that coronal heating occurs by means of anomalous Joule heating by electrostatic ion cyclotron waves is examined, with consideration given to currents running from foot of a loop to the other. It is assumed that self-fields generated by the currents are absent and currents follow the direction of the magnetic field, allowing the plasma cylinder to expand radially. Ion and electron heating rates are defined within the cylinder, together with longitudinal conduction and convection, radiation and cross-field transport, all in terms of Coulomb and turbulent effects. The dominant force is identified as electrostatic ion cyclotron instability, while ion acoustic modes remain stable. Rapid heating from an initial temperature of 10 eV to 100-1000 eV levels is calculated, with plasma reaching and maintaining a temperature in the 100 eV range. Strong heating is also possible according to the turbulent Ohm's law and by resistive heating.

Benford, G.

1983-01-01

206

Experimental and numerical investigation into the joule heating effect for electrokinetically driven microfluidic chips utilizing total internal reflection fluorescence microscopy  

Microsoft Academic Search

This paper presents a detection scheme for analyzing the temperature distribution nearby the channel wall in a microfluidic\\u000a chip utilizing a temperature-dependent fluorescence dye. An advanced optical microscope system—total internal reflection fluorescence\\u000a microscope (TIRFM) is used for measuring the temperature distribution on the channel wall at the point of electroosmotic flow\\u000a in an electrokinetically driven microfluidic chip. In order to

Lung-Ming Fu; Jing-Hui Wang; Wen-Bo Luo; Che-Hsin Lin

2009-01-01

207

High-resolution spatial mapping of the temperature distribution of a Joule self-heated graphene nanoribbon  

E-print Network

- ods such as micro-Raman spectroscopy, micro-infra-red, and confocal Raman spectroscopy.1­5 The spatial information on Appl. Phys. Lett. Journal Homepage: http://apl.aip.org/ Journal Information: http://apl.aip.org/about/about_the_journal using the Raman G mode Stokes/anti-Stokes intensity ratio as a function of electric power applied

Heinz, Tony F.

208

FY 2009 Annual Report of Joule Software Metric SC GG 3.1/2.5.2, Improve Computational Science Capabilities  

SciTech Connect

The Joule Software Metric for Computational Effectiveness is established by Public Authorizations PL 95-91, Department of Energy Organization Act, and PL 103-62, Government Performance and Results Act. The U.S. Office of Management and Budget (OMB) oversees the preparation and administration of the President s budget; evaluates the effectiveness of agency programs, policies, and procedures; assesses competing funding demands across agencies; and sets the funding priorities for the federal government. The OMB has the power of audit and exercises this right annually for each federal agency. According to the Government Performance and Results Act of 1993 (GPRA), federal agencies are required to develop three planning and performance documents: 1.Strategic Plan: a broad, 3 year outlook; 2.Annual Performance Plan: a focused, 1 year outlook of annual goals and objectives that is reflected in the annual budget request (What results can the agency deliver as part of its public funding?); and 3.Performance and Accountability Report: an annual report that details the previous fiscal year performance (What results did the agency produce in return for its public funding?). OMB uses its Performance Assessment Rating Tool (PART) to perform evaluations. PART has seven worksheets for seven types of agency functions. The function of Research and Development (R&D) programs is included. R&D programs are assessed on the following criteria: Does the R&D program perform a clear role? Has the program set valid long term and annual goals? Is the program well managed? Is the program achieving the results set forth in its GPRA documents? In Fiscal Year (FY) 2003, the Department of Energy Office of Science (DOE SC-1) worked directly with OMB to come to a consensus on an appropriate set of performance measures consistent with PART requirements. The scientific performance expectations of these requirements reach the scope of work conducted at the DOE national laboratories. The Joule system emerged from this interaction. Joule enables the chief financial officer and senior DOE management to track annual performance on a quarterly basis. Joule scores are reported as success, goal met (green light in PART), mixed results, goal partially met (yellow light in PART), and unsatisfactory, goal not met (red light in PART). Joule links the DOE strategic plan to the underlying base program targets.

Kothe, Douglas B [ORNL; Roche, Kenneth J [ORNL; Kendall, Ricky A [ORNL

2010-01-01

209

Effects of thermophoresis particle deposition and of the thermal conductivity in a porous plate with dissipative heat and mass transfer  

Microsoft Academic Search

Network simulation method (NSM) is used to solve the laminar heat and mass transfer of an electrically-conducting, heat generating\\/absorbing fluid past a perforated horizontal surface in the presence of viscous and Joule heating problem. The governing partial differential equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations, in a single independent variable, eta. The resulting

Joaquín Zueco; O. Anwar Bég; L. M. López-Ochoa

2011-01-01

210

Effects of thermophoresis particle deposition and of the thermal conductivity in a porous plate with dissipative heat and mass transfer  

Microsoft Academic Search

Network simulation method (NSM) is used to solve the laminar heat and mass transfer of an electrically-conducting, heat generating\\/absorbing\\u000a fluid past a perforated horizontal surface in the presence of viscous and Joule heating problem. The governing partial differential\\u000a equations are non-dimensionalized and transformed into a system of nonlinear ordinary differential similarity equations, in\\u000a a single independent variable, ?. The resulting

Joaquín Zueco; O. Anwar Bég; L. M. López-Ochoa

2011-01-01

211

A Si\\/Glass Bulk-Micromachined Cryogenic Heat Exchanger for High Heat Loads: Fabrication, Test, and Application Results  

Microsoft Academic Search

This paper reports on a micromachined Si\\/glass stack recuperative heat exchanger with in situ temperature sensors. Numerous high-conductivity silicon plates with integrated platinum resistance temperature detectors (Pt RTDs) are stacked, alternating with low-conductivity Pyrex spacers. The device has a 1 ?? 1-cm2 footprint and a length of up to 3.5 cm. It is intended for use in Joule-Thomson (J-T) coolers

Weibin Zhu; Michael J. White; Gregory F. Nellis; Sanford A. Klein; Yogesh B. Gianchandani

2010-01-01

212

Systematic analysis of direct-drive baseline designs for shock ignition with the Laser MégaJoule  

NASA Astrophysics Data System (ADS)

We present direct-drive target design studies for the laser mégajoule using two distinct initial aspect ratios (A = 34 and A = 5). Laser pulse shapes are optimized by a random walk method and drive power variations are used to cover a wide variety of implosion velocities between 260 km/s and 365 km/s. For selected implosion velocities and for each initial aspect ratio, scaled-target families are built in order to find self-ignition threshold. High-gain shock ignition is also investigated in the context of Laser MégaJoule for marginally igniting targets below their own self-ignition threshold.

Brandon, V.; Canaud, B.; Laffite, S.; Temporal, M.; Ramis, R.

2013-11-01

213

Dimensional Analysis of Thermoelectric Modules Under Constant Heat Flux  

NASA Astrophysics Data System (ADS)

Thermoelectric power generation is examined in the case of radiative heating. A constant heat flux is assumed in addition to consideration of the Seebeck effect, Peltier effect, and Joule heating with temperature-dependent material properties. Numerical evaluations are conducted using a combination of the finite-volume method and an original simultaneous solver for the heat transfer, thermoelectric, and electric transportation phenomena. Comparison with experimental results shows that the new solver could work well in the numerical calculations. The calculations predict that the Seebeck effect becomes larger for longer thermoelectric elements because of the larger temperature difference. The heat transfer to the cold surface is critical to determine the junction temperatures under a constant heat flux from the hot surface. The negative contribution from Peltier cooling and heating can be minimized when the current is smaller for longer elements. Therefore, a thicker TE module can generate more electric power even under a constant heat flux.

Suzuki, Ryosuke O.; Fujisaka, Takeyuki; Ito, Keita O.; Meng, Xiangning; Sui, Hong-Tao

2015-01-01

214

Enhanced heat transfer computations for internally cooled cable superconductor  

SciTech Connect

Superconducting magnets are built with conductors that are pool bath cooled, internally cooled with the superconductor cabled and contained within a conduit, or conduction cooled. The first two embody superconductors in direct contact with liquid helium. Practical designs of internally cooled cable superconductor (ICCS) are not cryostable. Such superconductors have shown multiple regions of stability and instability. A computational method of adjusting the heat transfer coefficient of a one dimensional system of equations to enhance joule heat removal, primarily in the central region of a pulse heated model of ICCS, has been used to attempt simulation of the multiple stability/instability experiment.

Rogers, J.D.

1985-01-01

215

Preionization and heating of plasma at the electron cyclotron frequency in JIPP T-II stellarator  

Microsoft Academic Search

Experimental studies of electron cyclotron preionization and heating are carried out in JIPP T-2 torus by injecting a power of 36 kW at the frequency of 35.5 GHz. Preionization effectively decreases the loop voltage required to start a joule heating and eliminates strong spikes in the signals of electron density, light emission as well as hard X ray which are

K. Ohkubo; K. Kawahata; K. Matsuoka; N. Noda; K. Sakurai; S. Tanahashi; K. Matsuura; K. Miyamoto; J. Fujita; M. Tanaka

1980-01-01

216

Technology, applications and modelling of ohmic heating: a review.  

PubMed

Ohmic heating or Joule heating has immense potential for achieving rapid and uniform heating in foods, providing microbiologically safe and high quality foods. This review discusses the technology behind ohmic heating, the current applications and thermal modeling of the process. The success of ohmic heating depends on the rate of heat generation in the system, the electrical conductivity of the food, electrical field strength, residence time and the method by which the food flows through the system. Ohmic heating is appropriate for processing of particulate and protein rich foods. A vast amount of work is still necessary to understand food properties in order to refine system design and maximize performance of this technology in the field of packaged foods and space food product development. Various economic studies will also play an important role in understanding the overall cost and viability of commercial application of this technology in food processing. Some of the demerits of the technology are also discussed. PMID:25328171

Varghese, K Shiby; Pandey, M C; Radhakrishna, K; Bawa, A S

2014-10-01

217

Simulation study on error propagation effects when determining second virial coefficients from the speed-of-sound or the Joule-Thomson experiment  

E-print Network

SIMULATION STUDY ON ERROR PROPAGATION EFFECTS WHEN DETERMINING SECOND VIRIAL COEFFICIENTS FROM THE SPEED-OF-SOUND OR THE JOULE-THOMSON EXPERIMENT A Thesis by DAVID J. VAN PEURSEM Submitted to the Office of Graduate Studies of Texas A...-OF-SOUND OR THE JOULE-THOMSON EXPERIMENT A Thesis by DAVID J. VAN PEURSEM Approved as to style and content by: P. T. Eubank (Committee Chair) R. R. Davison (Member) Randolph C. Wilhoit (Member) R. W. Flume elt (Department Head) August 1991 ABSTRACT...

Van Peursem, David J.

1991-01-01

218

Two-constant equation of state for accurate prediction of the Joule - Thomson inversion curve for air in cryogenic applications  

NASA Astrophysics Data System (ADS)

One of the most important applications of cryogenics is the separation and purification of air into its various components. Furthermore, of the many basic processes by which low temperatures are attained, the most commonly used in practical refrigerators is the Joule - Thomson expansion process. In this work the J - T inversion curve is predicted and compared with experimental data for air. Many equations of state such as VDW, RK, SRK and PR fail to obtain accurate prediction. Therefore, using numerical analysis, a simple two-constant equation of state is developed, which gives very favourable comparison with experiment, namely 2% maximum error in predicting thermodynamic properties, and 0.18 as average standard deviation for the J - T curve.

Najjar, Y. S. H.; Al-Beirutty, M. H.; Ismail, M. S.

219

Scaling, stability, and fusion mechanisms. Studies using plasma focus devices from tens of kilojoules to tenth of joules  

SciTech Connect

Fusion studies using plasma focus devices from tens of kilojoules to less than one joule performed at the Chilean Nuclear Energy Commission are presented. The similarity of the physical behavior and the scaling observed in these machines are emphasized. Experiments on actual devices show that scaling holds at least through six order of magnitude. In particular all of these devices, from the largest to the smallest, keep the same quantity of energy per particle. Therefore, fusion reactions are possible to be obtained in ultraminiature devices (driven by generators of 0.1 J), as they are in the bigger devices (driven by generators of 1 MJ). However, the stability of the plasma depends on the size and energy of the device.

Soto, Leopoldo; Pavez, Cristian; Moreno, Jose; Cardenas, Miguel [Comision Chilena de Energia Nuclear, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Tarifeno, Ariel [Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Universidad de Concepcion (Chile)

2009-01-21

220

Analytical solution for Joule-Thomson cooling during CO2 geo-sequestration in depleted oil and gas reservoirs  

SciTech Connect

Mathematical tools are needed to screen out sites where Joule-Thomson cooling is a prohibitive factor for CO{sub 2} geo-sequestration and to design approaches to mitigate the effect. In this paper, a simple analytical solution is developed by invoking steady-state flow and constant thermophysical properties. The analytical solution allows fast evaluation of spatiotemporal temperature fields, resulting from constant-rate CO{sub 2} injection. The applicability of the analytical solution is demonstrated by comparison with non-isothermal simulation results from the reservoir simulator TOUGH2. Analysis confirms that for an injection rate of 3 kg s{sup -1} (0.1 MT yr{sup -1}) into moderately warm (>40 C) and permeable formations (>10{sup -14} m{sup 2} (10 mD)), JTC is unlikely to be a problem for initial reservoir pressures as low as 2 MPa (290 psi).

Mathias, S.A.; Gluyas, J.G.; Oldenburg, C.M.; Tsang, C.-F.

2010-05-21

221

Empirically corrected HEAT method for calculating atomization energies  

SciTech Connect

We describe how to increase the accuracy ofthe most recent variants ofthe HEAT method for calculating atomization energies of molecules by means ofextremely simple empirical corrections that depend on stoichiometry and the number ofunpaired electrons in the molecule. Our corrections reduce the deviation from experiment for all the HEAT variants. In particular, our corrections reduce the average absolute deviation and the root-mean-square deviation ofthe 456-QP variant to 0.18 and 0.23 kJoule/mol (i.e., 0.04 and 0.05 kcallmol), respectively.

Brand, Holmann V [Los Alamos National Laboratory

2008-01-01

222

Role of thermal heating on the voltage induced insulator-metal transition in VO2.  

PubMed

We show that the main mechanism for the dc voltage or dc current induced insulator-metal transition in vanadium dioxide VO(2) is due to local Joule heating and not a purely electronic effect. This "tour de force" experiment was accomplished by using the fluorescence spectra of rare-earth doped micron sized particles as local temperature sensors. As the insulator-metal transition is induced by a dc voltage or dc current, the local temperature reaches the transition temperature indicating that Joule heating plays a predominant role. This has critical implications for the understanding of the dc voltage or dc current induced insulator-metal transition and has a direct impact on applications which use dc voltage or dc current to externally drive the transition. PMID:23414038

Zimmers, A; Aigouy, L; Mortier, M; Sharoni, A; Wang, Siming; West, K G; Ramirez, J G; Schuller, Ivan K

2013-02-01

223

Aerothermal Heating Predictions for Mars Microprobe  

NASA Technical Reports Server (NTRS)

A combination of computational predictions and experimental measurements of the aerothermal heating expected on the two Mars Microprobes during their entry to Mars are presented. The maximum, non-ablating, heating rate at the vehicle's stagnation point (at alpha = 0 degrees) is predicted for an undershoot trajectory to be 194 Watts per square centimeters with associated stagnation point pressure of 0.064 atm. Maximum stagnation point pressure occurs later during the undershoot trajectory and is 0.094 atm. From computations at seven overshoot-trajectory points, the maximum heat load expected at the stagnation point is near 8800 Joules per square centimeter. Heat rates and heat loads on the vehicle's afterbody are much lower than the forebody. At zero degree angle-of-attack, heating over much of the hemi-spherical afterbody is predicted to be less than 2 percent of the stagnation point value. Good qualitative agreement is demonstrated for forebody and afterbody heating between CFD calculations at Mars entry conditions and experimental thermographic phosphor measurements from the Langley 20-Inch Mach 6 Air Tunnel. A novel approach which incorporates six degree-of-freedom trajectory simulations to perform a statistical estimate of the effect of angle-of-attack, and other off-nominal conditions, on heating is included.

Mitcheltree, R. A.; DiFulvio, M.; Horvath, T. J.; Braun, R. D.

1998-01-01

224

Heat pipe array heat exchanger  

DOEpatents

A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

Reimann, Robert C. (Lafayette, NY)

1987-08-25

225

An Application of Space-Based Gas Mixtures for Joule-Thompson Cryocoolers  

NASA Astrophysics Data System (ADS)

An extension of deepspace research, specifically, the work done on Alpha program, will inevitably require new and different cryostating systems. The primary differences will be in the areas of cooling power and temperature. One variant which can be used with J-T cryocoolers is the application of diverse gas mixtures which can work over a large temperature range. We have found that the J-T cycle is an efficient application of mixed gas working fluids, being very similar to a vapor-compression cycle utilized in household refrigerants. The simplicity and viability of a J-T design and the associated minimal heat losses compensate for theoretical efficiency ratio of Stirling-type machines. Simultaneously, the J-T machines are never restricted in terms of output power and contain no moving parts in the cold zone resulting in minimal vibration during operation. The effective cooling of these systems allows parallel cooling of multiple objects. Finally in long-life system designs these cryocooler systems are feasibly coupled with phase-transition thermal storage accumulators. The application of such J-T systems is especially efficient under space conditions, due to the fact that there is an option to use at low temperatures a radiation release unit for the outlet of compression heat and for preliminary cooling of the system. This is not possible for terrestrial applications. Particularly, obtaining the -10 to 100 (C temperature range is feasible through the use of low As/(( - coefficient coatings; shade screens; or radiator unit orientations. Computational and experimental research has provided us high efficiency gas-mixture J-T cryocooler results between 60 to 100K cooling temperatures. We have actual space systems which were tested and operated for 80-90 K with efficiencies of 20 to 25 W/W. The authors of this research have studied various gas mixtures as candidates for use with simple J-T single contour J-T systems. We have seen resultant reduction of energy consumption by 2-3 times and decreases in temperatures from the 30-60( C range to -10 to 10( C range. We have also seen a dramatic reduction in the working pressure and the P/P pressure ratios within the cycle. We have gradually evolved into the application of simpler and more reliable working mixtures and employed more reliable single-stage compressors. In addition, the use of J-T contour gas mixtures for pre-cooling down to 35-40 K temperatures results in higher efficiency 2-stage J-T cryocoolers with similar overall results to the single stage systems.

Arkhipov, V. T.; Yevdokimova, O. V.; Lobko, M. P.; Yakuba, V. V.

226

New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes  

NASA Astrophysics Data System (ADS)

Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction.

Chen, G. F.; Gong, M. Q.; Wang, S.; Wu, J. F.; Zou, X.

2014-01-01

227

New flow boiling heat transfer model for hydrocarbons evaporating inside horizontal tubes  

SciTech Connect

Hydrocarbons have high thermodynamic performances, belong to the group of natural refrigerants, and they are the main components in mixture Joule-Thomson low temperature refrigerators (MJTR). New evaluations of nucleate boiling contribution and nucleate boiling suppression factor in flow boiling heat transfer have been proposed for hydrocarbons. A forced convection heat transfer enhancement factor correlation incorporating liquid velocity has also been proposed. In addition, the comparisons of the new model and other classic models were made to evaluate its accuracy in heat transfer prediction.

Chen, G. F.; Gong, M. Q.; Wu, J. F.; Zou, X. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); Wang, S. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, P.O. Box 2711, 35, Beijing, 100190 (China); University of Chinese Academy of Science, No. 19 YuQuan Road, Beijing, 100049 (China)

2014-01-29

228

Measurement and control of the movable coil position of a joule balance with a system based on a laser heterodyne interferometer  

NASA Astrophysics Data System (ADS)

A system based on laser heterodyne interferometer is proposed in this paper to measure and control the movable coil position of a joule balance. A damping system is used to suppress the movement of the movable coil in the horizontal direction while a piezoelectric ceramic control unit with PID controller is used to inhibit the vibration and long term drift of the movable coil in the vertical direction. The effectiveness of the proposed method in measuring and controlling the movable coil position of a joule balance is proved through experiments. Experimental results indicate that the displacement of the movable coil in the vertical direction can be reduced from 400 to 50 nm while its drift is successfully inhibited.

Yang, Hongxing; Lu, Yunfeng; Hu, Pengcheng; Li, Zhengkun; Zeng, Tao; He, Qing; Zhang, Zhonghua; Tan, Jiubin

2014-06-01

229

Micro-joule pico-second range Yb3+-doped fibre laser for medical applications in acupuncture  

NASA Astrophysics Data System (ADS)

The work described here is based on the optical design, simulation and on-going implementation of a pulsed (Q-switch) Yb3+-doped, 1-um diffraction-limited fibre laser with pico-second, 10 micro-Joule-range energy pulses for producing the right energy pulses which could be of benefit for patients who suffer chronic headache, photophobia, and even nausea which could is sometimes triggered by a series of factors. The specific therapeutic effect known as acupunctural analgesia is the main objective of this medium-term project. It is a simple design on which commercially available software was employed for laser cavity design. Monte Carlo technique for skin light-transport, thermal diffusion and the possible thermal de-naturalization optical study and prediction will also be included in the presentation. Full optical characterization will be included and a complete set of recent results on the laser-skin interaction and the so called moxi-bustion from the laser design will be extensively described.

Alvarez-Chavez, J. A.; Rivera-Manrique, S. I.; Jacques, S. L.

2011-08-01

230

Applicability of the Joule-Thomson Cryocooler Coupled with Membrane-Based Purification System for Liquefaction of Natural Gas in Small Quantities  

Microsoft Academic Search

Joule-Thomson (J-T) cryocoolers using gas mixture have been studied theoretically and experimentally for a variety of applications. Gas separation technology using polymer membrane is emerging. In this paper the concept of coupling the J-T cooler with a hollow fiber membranes is presented. The apparatus can be used in many applications, like compressed natural gas (CNG) purification and condensation into LNG

A. Piotrowska; M. Chorowski

2008-01-01

231

Numerical Studies of Fluid Leakage from a Geologic DisposalReservoir for CO2 Show Self-Limiting Feedback between Fluid Flow and HeatTransfer  

SciTech Connect

Leakage of CO2 from a hypothetical geologic storage reservoir along an idealized fault zone has been simulated, including transitions between supercritical, liquid, and gaseous CO2. We find strong non-isothermal effects due to boiling and Joule-Thomson cooling of expanding CO2. Leakage fluxes are limited by limitations in conductive heat transfer to the fault zone. The interplay between multiphase flow and heat transfer effects produces non-monotonic leakage behavior.

Pruess, Karsten

2005-03-22

232

Numerical studies of fluid leakage from a geologic disposal reservoir for CO2 show self-limiting feedback between fluid flow and heat transfer  

Microsoft Academic Search

Leakage of CO2 from a hypothetical geologic storage reservoir along an idealized fault zone has been simulated, including transitions between supercritical, liquid, and gaseous CO2. We find strong non-isothermal effects due to boiling and Joule-Thomson cooling of expanding CO2. Leakage fluxes are limited by limitations in conductive heat transfer to the fault zone. The interplay between multiphase flow and heat

Karsten Pruess

2005-01-01

233

Self-heating in normal metals and superconductors  

SciTech Connect

This review is devoted to the physics of current-carrying superconductors and normal metals having two or more stable states sustained by Joule self-heating. The creation, propagation, and localization of electrothermal domains and switching waves leading to the transition from one stable state to another in uniform and nonuniform samples are treated in detail. The connection between thermal bistability and hysteresis, dropping and stepped current-voltage characteristics, self-induced oscillations of current and voltage, self-replication of electrothermal domains, and the formation of periodic and stochastic resistive structures are considered.

Gurevich, A.V.; Mints, R.G.

1987-10-01

234

Cryogenic Joule annealing induced large magnetic field response of Co-based microwires for giant magneto-impedance sensor applications  

NASA Astrophysics Data System (ADS)

We have presented herein the results of microstructure, surface magnetic domains (SMDs), and giant magneto-impedance (GMI) effect of melt-extracted Co68.15Fe4.35Si12.25B11.25Nb2Cu2 amorphous wires for the first time employed by using a cryogenic Joule annealing (CJA) technique with large DC current amplitude. Compared with the conventional JA method, experimental results indicate that the maximum GMI ratio [?Z/Z0]max achieves up to 425% at 8.1 MHz with monotonic increase of the axial magnetic field Hex up to 6.5 Oe for 300 mA (equal to around 1.06 × 106 A/dm-2) CJA-ed wire, which is about 75% larger than the [?Z/Z0]max for the 100 mA (nearly 3.53 × 105 A/dm-2) JA-ed microwires. The remarkable features of large and linearly sensitive response field (2.5 ˜ 6.5 Oe) and the sensitivity of 99.4%/Oe with higher GMI ratio simultaneously make the CJA tailored melt-extracted microwires promising candidate materials for miniaturized GMI sensors. Another interesting result of GMI profiles of 200 mA (appropriately equal to 7.07 × 105 A/dm-2) CJA-ed wire show a linear response to Hex (ranging from 10 to 80 Oe or more), this behavior of GMI curves can be explored to fabricate bi-sensor. Large response field proves to originate from the intensive coupling between the radial stress field and the circumferential magnetic field during CJA process. The effect of outer-shell microstructure and complex SMD for 300 mA CJA-ed microwire is attributed to the fact that liquid nitrogen hinders the evolution of circumferential domain structure to some extent and protects the amorphous structure in the shell region.

Chen, D. M.; Xing, D. W.; Qin, F. X.; Liu, J. S.; Shen, H. X.; Peng, H. X.; Wang, H.; Sun, J. F.

2014-08-01

235

Highly lead-loaded red plastic scintillators as an X-ray imaging system for the Laser Mega Joule  

SciTech Connect

The scope of this project intends to record spatially resolved images of core shape and size of a DT micro-balloon during Inertial Confinement Fusion (ICF) experiments at Laser Mega Joule facility (LMJ). We need to develop an X-ray imaging system which can operate in the radiative background generated by an ignition shot of ICF. The scintillator is a part of the imaging system and has to gather a compromise of scintillating properties (scintillating efficiency, decay time, emission wavelength) so as to both operate in the hard radiative environment and to allow the acquisition of spatially resolved images. Inorganic scintillators cannot be used because no compromise can be found regarding the expected scintillating properties, most of them are not fast enough and emit blue light. Organic scintillators are generally fast, but present low X-ray absorption in the 10 to 40 keV range, that does not permit the acquisition of spatially resolved images. To this aim, we have developed highly lead-loaded and red-fluorescent fast plastic scintillators. Such a combination is not currently available via scintillator suppliers, since they propose only blue-fluorescent plastic scintillators doped with up to 12%w Pb. Thus, incorporation ratio up to 27%w Pb has been reached in our laboratory, which can afford a plastic scintillator with an outstanding Z{sub eff} close to 50. X-rays in the 10 to 40 keV range can thus be detected with a higher probability of photoelectric effect than for classic organic scintillators, such as NE102. The strong orange-red fluorescence can be filtered, so that we can eliminate residual Cerenkov light, generated by {gamma}-ray absorption in glass parts of the imaging system. Decay times of our scintillators evaluated under UV excitation were estimated to be in the range 10 to 13 ns. (authors)

Hamel, M.; Normand, S. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, F-91191 Gif-sur-Yvette (France); Turk, G.; Darbon, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2011-07-01

236

Continuous regeneration of an electrically heated diesel particulate trap: Mechanism of particulate matter trapping and improvement of trapping efficiency  

Microsoft Academic Search

The mechanisms of trapping and continuous regeneration of soot particles in a newly developed diesel particulate trap based on static-electric trapping (electrical diesel particulate trap, E-DPT) are investigated. It is found from a visualization experiment that soot particles trapped on the electro-plates form soot bridges over the 1.5 mm narrow space between the electro-plates and burn out by Joule's heating,

M Saito; H Hoshino; T Furuhata; M Arai

2010-01-01

237

Heat pumps  

NASA Astrophysics Data System (ADS)

Heat pumps for residential/commercial space heating and hot tap water make use of free energy of direct or indirect solar heat and save from about 40 to about 70 percent of energy if compared to a conventional heating system with the same energy basis. In addition, the electrically driven compressor heat pump is able to substitute between 40% (bivalent alternative operation) to 100% (monovalent operation) of the fuel oil of an oilfired heating furnace. For average Central European conditions, solar space heating systems with high solar coverage factor show the following sequence of increasing cost effectiveness: pure solar systems (without heat pumps); heat pump assisted solar systems; solar assisted heat pump systems; subsoil/water heat pumps; air/water heat pumps; air/air heat pumps.

Gilli, P. V.

1982-11-01

238

Use of Optical and Imaging Techniques for Inspection of Off-Line Joule-Heated Melter at the West Valley Demonstration Project  

SciTech Connect

The West Valley melter has been taken out of service. Its design is the direct ancestor of the current melter design for the Hanford Waste Treatment Plant. Over its eight years of service, the West Valley melter has endured many of the same challenges that the Hanford melter will encounter with feeds that are similar to many of the Hanford double shell tank wastes. Thus, inspection of the West Valley melter prior to its disposal could provide valuable--even crucial--information to the designers of the melters to be used at the Hanford Site, particularly if quantitative information can be obtained. The objective of Mississippi State University's Diagnostic Instrumentation and Analysis Laboratory's (DIAL) efforts is to develop, fabricate, and deploy inspection tools for the West Valley melter that will (i) be remotely operable in the West Valley process cell; (ii) provide quantitative information on melter refractory wear and deposits on the refractory; and (iii) indicate areas of heterogeneity (e.g., deposits) requiring more detailed characterization. A collaborative arrangement has been established with the West Valley Demonstration Project (WVDP) to inspect their melter.

Plodinec, M. J.; Jang, P-R; Long, Z.; Monts, D. L.; Philip, T.; Su, Y.

2003-02-25

239

Joule-level double-pulsed Ho:Tm:LuLF Master-Oscillator-Power-Amplifier (MOPA) for potential spaceborne lidar applications  

NASA Astrophysics Data System (ADS)

Spaceborne coherent Doppler wind lidars and CO2 Differential Absorption Lidars (DIALs) at eye-safe 2-?m spectral range have been proposed for several years for accurate global wind and carbon-oxide concentration profiling measurement. These lidar systems require Joule level laser pulse energy from laser transmitter and high efficiency. In this paper, we report a diode-pumped Ho:Tm:LuLF Master-Oscillator-Power-Amplifier (MOPA) developed to demonstrate Joule level output pulse energy. The MOPA consists of one master oscillator and two power amplifiers. The master oscillator was Q-switched and can be operated at single pulse mode or double pulse mode respectively. The single pulse operation is used for a coherent Doppler wind lidar and the double pulse operation for a CO2 Differential Absorption Lidar (DIAL). The output pulse energy of the master oscillator is 115 mJ for the single pulse operation and 186 mJ for the double pulse operation. To extract more energy from the pumping pulses and increase the efficiency of the MOPA, the first amplifier was set at a double pass configuration. The second amplifier was set at a single pass configuration to avoid the damage problem of the Ho:Tm:LuLF laser rod. Total output pulse energy of 0.63 J with an optical efficiency of 4.1% for single pulse operation and 1.05 J with an optical efficiency of 6.9% for double pulse operation were demonstrated.

Chen, Songsheng; Yu, Jirong; Petros, Mulugeta; Bai, Yingxin; Singh, Upendra N.; Kavaya, Michael J.

2005-01-01

240

Electromagnetohydrodynamic flow of blood and heat transfer in a capillary with thermal radiation  

NASA Astrophysics Data System (ADS)

This paper presents a comprehensive theoretical study on heat transfer characteristics together with fully developed electromagnetohydrodynamic flow of blood through a capillary, having electrokinetic effects by considering the constant heat flux at the wall. The effect of thermal radiation and velocity slip condition have been taken into account. A rigorous mathematical model for describing Joule heating in electro-osmotic flow of blood including the Poisson-Boltzmann equation, the momentum equation and the energy equation is developed. The alterations in the thermal transport phenomenon, induced by the variation of imposed electromagnetic effects, are thoroughly explained through an elegant mathematical formalism. Results presented here pertain to the case where the height of the capillary is much greater than the thickness of electrical double layer comprising the stern and diffuse layers. The essential features of the electromagnetohydrodynamic flow of blood and associated heat transfer characteristics through capillary are clearly highlighted by the variations in the non-dimensional parameters for velocity profile, temperature profile and the Nusselt number. The study reveals that the temperature of blood can be controlled by regulating Joule heating parameter.

Sinha, A.; Shit, G. C.

2015-03-01

241

Numerical investigation of the plasma flow through the constrictor of arc-heated thrusters  

NASA Astrophysics Data System (ADS)

A modelling study is performed to investigate the plasma flow through the constrictor of medium-power arc-heated thrusters. The Roe scheme is employed to solve the governing equations, which take into account the effects of compressibility, Joule heating and the Lorentz force, as well as the temperature and pressure dependence of the gas properties. The modelling results show that the gas flow within the constrictor is choked by the combined effects of friction and arc heating. The computed total pressure drop within the constrictor due to friction and arc heating is about twice the dynamic head at the constrictor outlet. The effects of the arc current, inlet pressure and mass flow rate, and the constrictor length and diameter on the gas flow characteristics within the constrictor are presented and discussed. Further, it is shown that the choking effects caused by arc heating reduce the flow rate more strongly for argon and nitrogen working gases than for hydrogen working gas.

Wang, Hai-Xing; Wei, Fu-Zhi; Murphy, A. B.; Liu, Yu

2012-06-01

242

Electrical heating of soils using high efficiency electrode patterns and power phases  

DOEpatents

Powerline-frequency electrical (joule) heating of soils using a high efficiency electrode configuration and power phase arrangement. The electrode configuration consists of several heating or current injection electrodes around the periphery of a volume of soil to be heated, all electrodes being connected to one phase of a multi-phase or a single-phase power system, and a return or extraction electrode or electrodes located inside the volume to be heated being connected to the remaining phases of the multi-phase power system or to the neutral side of the single-phase power source. This electrode configuration and power phase arrangement can be utilized anywhere where powerline frequency soil heating is applicable and thus has many potential uses including removal of volatile organic compounds such as gasoline and tricholorethylene (TCE) from contaminated areas.

Buettner, Harley M. (Livermore, CA)

1999-01-01

243

Optical cell with periodic resistive heating for the measurement of heat, mass, and thermal diffusions in liquid mixtures  

SciTech Connect

A new technique for the measurement of heat, mass, and thermal diffusions in liquids has been developed. Similar to laser induced dynamic gratings, a temperature grating is created in the sample. Thermal expansion transforms the temperature into a refractive-index grating, which is read by diffraction of a readout laser beam. In a multicomponent mixture an additional concentration grating is formed by thermal diffusion driven by the temperature gradients of the temperature grating. Differently to laser induced dynamic grating experiments we use Joule heating instead of optical heating. For that purpose we have built cuvettes which have a grating of transparent conducting strips on the inner side of one of their windows. If heated by an electric current a temperature grating will build up in the sample. Both the heat equation and the extended diffusion equation have been solved in two dimensions to allow for quantitative data analysis. Our apparatus and method of analysis have been validated by measurements of heat, mass, and thermal diffusions in pure and binary liquids. Heat diffusion can be correctly determined as was shown for pure toluene, pure dodecane, and the symmetric mixture of isobutylbenzene dodecane. Mass and thermal diffusions were studied in the three symmetric mixtures of dodecane, isobutylbenzene, and tetralin. The obtained diffusion and Soret coefficients agree with the literature values within the experimental errors. Uncompensated transient heating effects limit the resolution of the experimental technique.

Hartung, M.; Koehler, W. [Physikalisches Institut, Universitaet Bayreuth, D-95440 Bayreuth (Germany)

2007-08-15

244

Heat waves  

Microsoft Academic Search

The concept of transmission of heat by waves is reviewed and interpreted. The notion of an effective thermal conductivity, an effective heat capacity, and relaxation functions for heat and energy is introduced along lines used recently to describe the elastic response of viscous liquids. An annotated bibliography of the literature on heat waves, from the beginning until now, gives a

D. D. Joseph; Luigi Preziosi

1989-01-01

245

Empirical analysis of contributing factors to heating in lithium-ion cells: Anode entropy versus internal resistance  

NASA Astrophysics Data System (ADS)

Charging a battery beyond its maximum capacity can lead both to cell overheating and to the venting of gasses. A fundamental understanding of cell heating could lead to the development of real-time sensors that anticipate and avert catastrophic battery failure. Joule heating (also called ohmic or resistive heating) from cell internal resistance (Rint) dominates the overall thermal energy (?Q) generated during charging. Contrary to prior hypotheses, though, Joule heating does not appear to contribute to venting observed during overcharging. In this manuscript, we examine an alternate hypothesis, that heat released by the entropy change in the anode (?Sanode) and the concomitant increase in the anode temperature (Tanode) triggers the venting. Using our recently developed non-invasive battery internal temperature (BIT) sensor to monitor Tanode, we separated the contributions of ?Sanode, Rint and the anode resistance (Ranode) to ?Q. These quantities were tracked during constant current charging of a 18650 Lithium-ion cell, from zero state of charge (SoC) to overcharge. The resulting analysis suggests that anode entropy change is more important than resistive heating resulting from Ranode to the overall thermal energy. Anode entropy measurements, enabled by the BIT sensor, might serve as an alternative or adjunct method for anticipating and avoiding cell venting events.

Srinivasan, Rengaswamy; Carkhuff, Bliss G.

2013-11-01

246

Nanowire heating by optical electromagnetic irradiation.  

PubMed

The dissipative absorption of electromagnetic energy by 1D nanoscale structures at optical frequencies is applicable to several important phenomena, including biomedical photothermal theranostics, nanoscale photovoltaic materials, atmospheric aerosols, and integrated photonic devices. Closed-form analytical calculations are presented for the temperature rise within infinite circular cylinders with nanometer-scale diameters (nanowires) that are irradiated at right angles by a continuous-wave laser source polarized along the nanowire's axis. Solutions for the heat source are compared to both numerical finite-difference time domain (FDTD) simulations and well-known Mie scattering cross sections for infinite cylinders. The analysis predicts that the maximum temperature increase is affected not only by the cylinder's composition and porosity but also by morphology-dependent resonances (MDRs) that lead to significant spikes in the local temperature at particular diameters. Furthermore, silicon nanowires with high thermal conductivities are observed to exhibit extremely uniform internal temperatures during electromagnetic heating to 1 part in 10(6), including cases where there are substantial fluctuations of the internal electric-field source term that generates the Joule heating. For a highly absorbing material such as carbon, much higher temperatures are predicted, the internal temperature distribution is nonuniform, and MDRs are not encountered. PMID:23061375

Roder, Paden B; Pauzauskie, Peter J; Davis, E James

2012-11-20

247

Railgun conductor heating from multiple current pulses  

SciTech Connect

A numerical technique for solving current- and thermal-diffusion problems in railgun conductors has been used to study joule heating in rails that are subject to multiple current pulses. Copper rails that are 25 mm high by the 12.5 mm wide with a 20-mm-square bore and a current pulse with 1-MA peak current and 1-ms pulse width at half maximum were assumed. This combination of parameters is sufficient to accelerate an 80-g projectile to 2-3 km/s with which current pulse. Three parameters were varied in the analysis: the repetition rate or current pulse frequency (3.3 to 100 Hz), the coolant heat-transfer coefficient (5 x 10/sup 4/ and 5 x 10/sup 5/ W/m/sup 2/ .K), and the coolant channel distribution in the rail. Detailed results are used to illustrate the acceptability or unacceptability of particular combinations of these parameters for operation at steady state. An uncooled rail was not acceptable for steady-state operation. Repetition rates of about 30 Hz were acceptable with the higher coolant heat-transfer coefficient and the best coolant-channel distribution; this included cooling the rail exterior surface.

Kerrisk, J.F.

1986-01-01

248

A compact low cost "master-slave" double crystal monochromator for x-ray cameras calibration of the Laser MégaJoule Facility  

NASA Astrophysics Data System (ADS)

The Alternative Energies and Atomic Energy Commission (CEA-CESTA, France) built a specific double crystal monochromator (DCM) to perform calibration of x-ray cameras (CCD, streak and gated cameras) by means of a multiple anode diode type x-ray source for the MégaJoule Laser Facility. This DCM, based on pantograph geometry, was specifically modeled to respond to relevant engineering constraints and requirements. The major benefits are mechanical drive of the second crystal on the first one, through a single drive motor, as well as compactness of the entire device. Designed for flat beryl or Ge crystals, this DCM covers the 0.9-10 keV range of our High Energy X-ray Source. In this paper we present the mechanical design of the DCM, its features quantitatively measured and its calibration to finally provide monochromatized spectra displaying spectral purities better than 98%.

Hubert, S.; Prévot, V.

2014-12-01

249

The heating of the temperature minimum region in solar flares - A reassessment  

NASA Technical Reports Server (NTRS)

The paper discusses and evaluates the suggestions made by Machado et al. (1978) on how to reconcile the observed temperature enhancements at temperature-minimum levels in solar flares with some theoretical heating mechanism. The objective is to gain deeper insight into the nature of the photospheric flare. The discussion focuses on the validity of the assumption of H(-) LTE at temperature-minimum levels, as well as on EUV irradiation and Joule heating by steady currents as heating mechanisms. It is found that, unless there are strong inhomogeneities associated with either heating mechanism, neither can reasonably be reconciled with observations. It is concluded that detailed high-resolution (both spatial and temporal) measurements are necessary to further the present understanding of the flare process at temperature-minimum levels.

Emslie, A. G.; Machado, M. E.

1979-01-01

250

Size distribution and critical supersaturation spectrum of the aerosol from an electrically heated nichrome wire  

NASA Astrophysics Data System (ADS)

An aerosol generator was constructed that produces particles from the Joule heating of a nichrome wire. This novel generator produced a stable output (+/-20%) over a 7 hour period. The approximate mean diameter was 24 nm. The critical supersaturation spectrum was measured and found to be quite high (5.4% for 24 nm particles), showing that this nichrome aerosol was highly insoluble. Energy dispersive spectroscopy showed that the percentage of Cr far exceeded that of Ni in the particles, whereas in the bulk wire, Cr has only one third the concentration of Ni.

Trueblood, Max B.; Carter, Millard A.; Hagen, Donald E.; Whitefield, Philip D.; Podzimek, Josef

2000-08-01

251

Vacuum vessel heating system for the Advanced Toroidal Facility  

SciTech Connect

An 80-kW system for heating the Advanced Toroidal Facility (ATF) stainless-steel vacuum vessel to 150 /sup 0/C, the design limit of the vessel, has been designed. The system's primary purpose is to accelerate the outgassing of the vessel walls during the initial pumpdown following an opening to atmospheric pressure. It will also measure the thermal time constant of the vessel. These measurements are important for assessing the vessel's power-handling capability. The main body of the vessel is induction heated by applying 440-V, 60-Hz power directly to the main torsatron windings. The eddy currents that this power induces in the vessel produce an estimated 50 kW of joule heating. The vacuum vessel temperature is measured with an array of thermocouples. A programmable logic controller regulates the temperature and provides interlock and overheating protection. A system of 60 heating tapes, each rated at 520 W, is installed on the ports and ducts attached to the vessel. This system, in conjunction with the induction heating system, is planned to provide temperature uniformity. The total heating power and rates of rise and fall of the vessel temperature have been calculated using a model of the vacuum vessel. The results are given.

Langley, R.A.; Neilson, G.H.; Alban, A.M.; Slaughter, E.; Sumner, J.N.; White, J.A.

1988-05-01

252

Vacuum vessel heating system for ATF (Advanced Toroidal Facility)  

SciTech Connect

An 80-kW system for heating the Advanced Toroidal Facility (ATF) stainless steel vacuum vessel to 150/sup 0/C, the design limit of the vessel, has been designed. The system's primary purpose is to accelerate the outgassing of the vessel walls during the initial pumpdown following an opening to atmospheric pressure. It will also measure the thermal time constant of the vessel. These measurements are important for assessing the vessel's power-handling capability. The main body of the vessel is induction heated by applying 440-V, 60-Hz power directly to the main torsatron windings. The eddy currents that this power induces in the vessel produce an estimated 50 kW of Joule heating. The vacuum vessel temperature is measured with an array of thermocouples. A programmable logic controller regulates the temperature and provides interlock and overheating protection. A system of 60 heating tapes, each rated at 520 W, is installed on the ports and ducts attached to the vessel. This system, in conjunction with the induction heating systems, is planned to provide temperature uniformity. The total heating power and rates of rise and fall of the vessel temperature have been calculated using a model of the vacuum vessel. The results are given.

Langley, R.A.; Neilson, G.H.; Alban, A.M.; Slaughter, E.; Sumner, J.N.; White, J.A.

1987-01-01

253

Heat Pipes  

NASA Technical Reports Server (NTRS)

Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

1991-01-01

254

Heat Pipes  

NASA Technical Reports Server (NTRS)

Heat Pipes were originally developed by NASA and the Los Alamos Scientific Laboratory during the 1960s to dissipate excessive heat build- up in critical areas of spacecraft and maintain even temperatures of satellites. Heat pipes are tubular devices where a working fluid alternately evaporates and condenses, transferring heat from one region of the tube to another. KONA Corporation refined and applied the same technology to solve complex heating requirements of hot runner systems in injection molds. KONA Hot Runner Systems are used throughout the plastics industry for products ranging in size from tiny medical devices to large single cavity automobile bumpers and instrument panels.

1996-01-01

255

Steady state heat transfer experimental studies of LHC superconducting cables operating in cryogenic environment of superfluid helium  

E-print Network

The heat management is a basic and fundamental aspect of the superconducting magnets used in the CERN Large Hadron Collider. Indeed, the coil temperature must be kept below the critical value, despite the heat which can be generated or deposited in the magnet during the normal operations. Therefore, this thesis work aims at determining the heating power which can be extracted from the superconducting cables of the LHC, specially through their electrical insulation which represents the main thermal barrier. An experimental measurement campaign in superfluid helium bath was performed on several samples reproducting the main LHC magnets. The heating power was generated in the sample by Joule heating and the temperature increase was measured by means of Cernox bare chip and thermocouples. An innovative instrumentation technique which also includes the in-situ calibration of the thermocouples was developed. A thorough uncertainty analysis on the overall measurement chain concluded the experimental setup. The prese...

Santandrea, Dario; Tuccillo, Raffaele; Granieri, Pier Paolo.

256

Preliminary analysis of heat pipe heat exchangers for heat recovery  

Microsoft Academic Search

A preliminary analysis of fin tube heat pipe heat exchangers for air-to-air heat recovery was conducted. The analysis uses conventional heat exchanger design techniques and a new heat pipe design technique which includes probabilistic design of artery wick heat pipes. The heat transfer capability of the heat pipes may be matched with that of the finned tubes in order to

J. O. Amode; K. T. Feldman

1975-01-01

257

Heat collector  

SciTech Connect

A heat collector for a solar heat utilization system comprises a heat collecting pipe and a reflecting plate for focusing solar light on the pipe. This pipe has a first tubular portion for receiving solar light collected by the reflecting plate, and a second tubular portion for receiving direct solar light. The second portion has thermal expansion coefficient larger by a predetermined amount than that of the first portion, and thermally expands at the same rate as the first portion.

Nameda, N.; Nakamoto, Y.; Sekiya, H.; Surisawa, Y.

1985-03-19

258

Heat Transfer  

NSDL National Science Digital Library

Students explore heat transfer and energy efficiency using the context of energy efficient houses. They gain a solid understanding of the three types of heat transfer: radiation, convection and conduction, which are explained in detail and related to the real world. They learn about the many ways solar energy is used as a renewable energy source to reduce the emission of greenhouse gasses and operating costs. Students also explore ways in which a device can capitalize on the methods of heat transfer to produce a beneficial result. They are given the tools to calculate the heat transferred between a system and its surroundings.

2014-09-18

259

Multiphysics Modeling for Dimensional Analysis of a Self-Heated Molten Regolith Electrolysis Reactor for Oxygen and Metals Production on the Moon and Mars  

NASA Technical Reports Server (NTRS)

The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a self-heating reactor in which the electrolytic currents generate enough Joule heat to create a molten bath.

Dominguez, Jesus; Sibille, Laurent

2010-01-01

260

Decay HeatDecay Heat NCF structure decay heat is  

E-print Network

Be instead of Pb in re-circulating blanket enhances TBR by ~6% and nuclear heating by ~10% Activity and decay in re-circulating blanket enhances TBR by ~6% and nuclear heating by ~10% Activity and decay heatDecay HeatDecay Heat NCF structure decay heat is much larger than Flibe decay heat for t > 1 minute

261

A Si/Glass Bulk-Micromachined Cryogenic Heat Exchanger for High Heat Loads: Fabrication, Test, and Application Results.  

PubMed

This paper reports on a micromachined Si/glass stack recuperative heat exchanger with in situ temperature sensors. Numerous high-conductivity silicon plates with integrated platinum resistance temperature detectors (Pt RTDs) are stacked, alternating with low-conductivity Pyrex spacers. The device has a 1 x 1-cm(2) footprint and a length of up to 3.5 cm. It is intended for use in Joule-Thomson (J-T) coolers and can sustain pressure exceeding 1 MPa. Tests at cold-end inlet temperatures of 237 K-252 K show that the heat exchanger effectiveness is 0.9 with 0.039-g/s helium mass flow rate. The integrated Pt RTDs present a linear response of 0.26%-0.30%/K over an operational range of 205 K-296 K but remain usable at lower temperatures. In self-cooling tests with ethane as the working fluid, a J-T system with the heat exchanger drops 76.1 K below the inlet temperature, achieving 218.7 K for a pressure of 835.8 kPa. The system reaches 200 K in transient state; further cooling is limited by impurities that freeze within the flow stream. In J-T self-cooling tests with an external heat load, the system reaches 239 K while providing 1 W of cooling. In all cases, there is an additional parasitic heat load estimated at 300-500 mW. PMID:20490284

Zhu, Weibin; White, Michael J; Nellis, Gregory F; Klein, Sanford A; Gianchandani, Yogesh B

2010-02-01

262

A Si/Glass Bulk-Micromachined Cryogenic Heat Exchanger for High Heat Loads: Fabrication, Test, and Application Results  

PubMed Central

This paper reports on a micromachined Si/glass stack recuperative heat exchanger with in situ temperature sensors. Numerous high-conductivity silicon plates with integrated platinum resistance temperature detectors (Pt RTDs) are stacked, alternating with low-conductivity Pyrex spacers. The device has a 1 × 1-cm2 footprint and a length of up to 3.5 cm. It is intended for use in Joule–Thomson (J–T) coolers and can sustain pressure exceeding 1 MPa. Tests at cold-end inlet temperatures of 237 K–252 K show that the heat exchanger effectiveness is 0.9 with 0.039-g/s helium mass flow rate. The integrated Pt RTDs present a linear response of 0.26%–0.30%/K over an operational range of 205 K–296 K but remain usable at lower temperatures. In self-cooling tests with ethane as the working fluid, a J–T system with the heat exchanger drops 76.1 K below the inlet temperature, achieving 218.7 K for a pressure of 835.8 kPa. The system reaches 200 K in transient state; further cooling is limited by impurities that freeze within the flow stream. In J–T self-cooling tests with an external heat load, the system reaches 239 K while providing 1 W of cooling. In all cases, there is an additional parasitic heat load estimated at 300–500 mW. PMID:20490284

Zhu, Weibin; White, Michael J.; Nellis, Gregory F.; Klein, Sanford A.; Gianchandani, Yogesh B.

2010-01-01

263

Applicability of the Joule-Thomson Cryocooler Coupled with Membrane-Based Purification System for Liquefaction of Natural Gas in Small Quantities  

NASA Astrophysics Data System (ADS)

Joule-Thomson (J-T) cryocoolers using gas mixture have been studied theoretically and experimentally for a variety of applications. Gas separation technology using polymer membrane is emerging. In this paper the concept of coupling the J-T cooler with a hollow fiber membranes is presented. The apparatus can be used in many applications, like compressed natural gas (CNG) purification and condensation into LNG or separation and liquefaction of nitrogen from air. The paper describes the system and experimental dependence of the separated nitrogen purity on the membrane inlet air pressure. The Second Law of Thermodynamics is used to optimize the composition of the mixture for natural gas cooling and liquefaction. Possible applications of the system depend on membrane material. Membranes used in separation of N2/air or CO2/CH4 are now commercially available [2,6]. The combination of the J-T cooler with N2/air membrane enables the construction of the liquid nitrogen production system aimed at cryosurgical applications. Similarly, J-T cooler coupled with CO2/CH4 membrane can be used for purification and liquefaction of natural gas in small quantities e.g. satisfying future car refueling system needs.

Piotrowska, A.; Chorowski, M.

2008-03-01

264

Heat Problems.  

ERIC Educational Resources Information Center

Heat problems and heat cramps related to jogging can be caused by fluid imbalances, medications, dietary insufficiency, vomiting or diarrhea, among other factors. If the condition keeps reoccurring, the advice of a physician should be sought. Some preventive measures that can be taken include: (1) running during the cooler hours of the day; (2)…

Connors, G. Patrick

265

Heat stroke.  

PubMed

Heat stroke is a life-threatening condition clinically diagnosed as a severe elevation in body temperature with central nervous system dysfunction that often includes combativeness, delirium, seizures, and coma. Classic heat stroke primarily occurs in immunocompromised individuals during annual heat waves. Exertional heat stroke is observed in young fit individuals performing strenuous physical activity in hot or temperature environments. Long-term consequences of heat stroke are thought to be due to a systemic inflammatory response syndrome. This article provides a comprehensive review of recent advances in the identification of risk factors that predispose to heat stroke, the role of endotoxin and cytokines in mediation of multi-organ damage, the incidence of hypothermia and fever during heat stroke recovery, clinical biomarkers of organ damage severity, and protective cooling strategies. Risk factors include environmental factors, medications, drug use, compromised health status, and genetic conditions. The role of endotoxin and cytokines is discussed in the framework of research conducted over 30 years ago that requires reassessment to more clearly identify the role of these factors in the systemic inflammatory response syndrome. We challenge the notion that hypothalamic damage is responsible for thermoregulatory disturbances during heat stroke recovery and highlight recent advances in our understanding of the regulated nature of these responses. The need for more sensitive clinical biomarkers of organ damage is examined. Conventional and emerging cooling methods are discussed with reference to protection against peripheral organ damage and selective brain cooling. © 2015 American Physiological Society. Compr Physiol 5: 611-647, 2015. PMID:25880507

Leon, Lisa R; Bouchama, Abderrezak

2015-03-01

266

Magnetic and magnetoimpedance studies on controlled Joule annealed amorphous Co73Fe4.5Ni0.5Mn0.5Nb0.5Si4.2B16.8 alloy  

NASA Astrophysics Data System (ADS)

We report magnetic and magnetoimpedance (MI) properties of as-quenched and Joule annealed (with and without external magnetic field) amorphous Co73Fe4.5Ni0.5Mn0.5Nb0.5Si4.2B16.8 alloy composition. The Joule annealing in the presence of magnetic field induces not only surface microstructural changes but also favourable anisotropy. Dc magnetic measurements show controlled annealing enhances soft magnetic nature of the sample. Virgin ribbons show MS ˜ 125 emu/g with ?r ˜ 104 and exhibit large MI ratio of ˜100% at 3 MHz frequency. This MI ratio was further enhanced to 152% on Joule annealing (current density 0.85 × 107 A/m2) in the presence of applied magnetic field of 500 Oe. The field dependence MI shows a double-peak feature in as-spun ribbons, which is significantly enhanced for field annealed (FA) samples. The enhancement in MI and magnetic field sensitivity (?) in FA amorphous ribbons is attributed to the development of nanograins on the surface layer that strengthens the transverse magnetic structure.

Kumar Manna, Subhendu; Srinivas, V.

2014-05-01

267

Heat collector  

DOEpatents

A heat collector and method suitable for efficiently and cheaply collecting solar and other thermal energy are provided. The collector employs a heat pipe in a gravity-assist mode and is not evacuated. The collector has many advantages, some of which include ease of assembly, reduced structural stresses on the heat pipe enclosure, and a low total materials cost requirement. Natural convective forces drive the collector, which after startup operates entirely passively due in part to differences in molecular weights of gaseous components within the collector.

Merrigan, M.A.

1981-06-29

268

Heat collector  

DOEpatents

A heat collector and method suitable for efficiently and cheaply collecting solar and other thermal energy are provided. The collector employs a heat pipe in a gravity-assist mode and is not evacuated. The collector has many advantages, some of which include ease of assembly, reduced structural stresses on the heat pipe enclosure, and a low total materials cost requirement. Natural convective forces drive the collector, which after startup operates entirely passively due in part to differences in molecular weights of gaseous components within the collector.

Merrigan, Michael A. (Santa Cruz, NM)

1984-01-01

269

Energy-Saving Sintering of Electrically Conductive Powders by Modified Pulsed Electric Current Heating Using an Electrically Nonconductive Die  

NASA Astrophysics Data System (ADS)

Sintering of Cu and thermoelectric Ca3Co4O9 was tried using a modified pulsed electric current sintering (PECS) process, where an electrically nonconductive die was used instead of a conventional graphite die. The pulsed electric current flowed through graphite punches and sample powder, which caused the Joule heating of the powder compact itself, resulting in sintering under smaller power consumption. Especially for the Ca3Co4O9 powder, densification during sintering was also accelerated by this modified PECS process.

Ito, Mikio; Kawahara, Kenta; Araki, Keita

2014-04-01

270

Analytical model for self-heating in nanowire geometries  

NASA Astrophysics Data System (ADS)

An analytical closed form diffusive model is developed of Joule heating in a device consisting of a nanowire connected to two contacts on a substrate. This analytical model is compared to finite-element simulations and demonstrates excellent agreement over a wider range of system parameters in comparison to other recent models, with particularly large improvements in cases when the width of the nanowire is less than the thermal healing length of the contacts and when the thermal resistance of the contact is appreciable relative to the thermal resistance of the nanowire. The success of this model is due to more accurately accounting for the heat spreading within the contact region of a device and below the nanowire into a substrate. The heat spreading is achieved by matching the linear heat flow near the nanowire interfaces with a radially symmetric spreading solution through an interpolation function. Additional features of this model are the ability to incorporate contact resistances that may be present at the nanowire-contact interfaces, as well as accommodating materials with a linear temperature-dependent electrical resistivity.

Hunley, D. Patrick; Johnson, Stephen L.; Flores, Roel L.; Sundararajan, Abhishek; Strachan, Douglas R.

2013-06-01

271

Corrosive resistant heat exchanger  

DOEpatents

A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

Richlen, Scott L. (Annandale, VA)

1989-01-01

272

Heating and cooling system  

Microsoft Academic Search

An environment heating and cooling system is described which consists of a solar collector, heat storage ground well, cold storage ground well, and a heat exchange apparatus. Water from a cold storage ground well is heated in the heat exchange apparatus by solar heating fluid heated in a solar collector. The heated water is stored in a heat storage ground

1976-01-01

273

Pressure drop characteristics of cryogenic mixed refrigerant at macro and micro channel heat exchangers  

NASA Astrophysics Data System (ADS)

Mixed Refrigerant-Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. The temperature glide effect is one of the major features of using mixed refrigerants since a recuperative heat exchanger in a MR-JT refrigerator is utilized for mostly two-phase flow. Although a pressure drop estimation for a multi-phase and multi-component fluid in the cryogenic temperature range is necessarily required in MR-JT refrigerator heat exchanger designs, it has been rarely discussed so far. In this paper, macro heat exchangers and micro heat exchangers are compared in order to investigate the pressure drop characteristics in the experimental MR-JT refrigerator operation. The tube in tube heat exchanger (TTHE) is a well-known macro-channel heat exchanger in MR-JT refrigeration. Printed Circuit Heat Exchangers (PCHEs) have been developed as a compact heat exchanger with micro size channels. Several two-phase pressure drop correlations are examined to discuss the experimental pressure measurement results. The result of this paper shows that cryogenic mixed refrigerant pressure drop can be estimated with conventional two-phase pressure drop correlations if an appropriate flow pattern is identified.

Baek, Seungwhan; Jeong, Sangkwon; Hwang, Gyuwan

2012-12-01

274

Modular Heat Exchanger With Integral Heat Pipe  

NASA Technical Reports Server (NTRS)

Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

Schreiber, Jeffrey G.

1992-01-01

275

Heat Pipes  

NASA Technical Reports Server (NTRS)

Bobs Candies, Inc. produces some 24 million pounds of candy a year, much of it 'Christmas candy.' To meet Christmas demand, it must produce year-round. Thousands of cases of candy must be stored a good part of the year in two huge warehouses. The candy is very sensitive to temperature. The warehouses must be maintained at temperatures of 78-80 degrees Fahrenheit with relative humidities of 38- 42 percent. Such precise climate control of enormous buildings can be very expensive. In 1985, energy costs for the single warehouse ran to more than $57,000 for the year. NASA and the Florida Solar Energy Center (FSEC) were adapting heat pipe technology to control humidity in building environments. The heat pipes handle the jobs of precooling and reheating without using energy. The company contacted a FSEC systems engineer and from that contact eventually emerged a cooperative test project to install a heat pipe system at Bobs' warehouses, operate it for a period of time to determine accurately the cost benefits, and gather data applicable to development of future heat pipe systems. Installation was completed in mid-1987 and data collection is still in progress. In 1989, total energy cost for two warehouses, with the heat pipes complementing the air conditioning system was $28,706, and that figures out to a cost reduction.

1990-01-01

276

Heat pipe waste heat recovery boilers  

Microsoft Academic Search

The use of heat pipes as transport devices in waste heat recovery boilers is examined. Test results show that heat pipes can efficiently extract heat from the hot gas stream and transfer it inside the pressure vessel for the steam generation process. The benefits of incorporating heat pipes into the design of waste heat recovery boilers include a highly compact

D. A. Littwin; J. McCurley

1981-01-01

277

The cooling effect of tubular liquid flow during radiofrequency heating: the "rind" survival hypothesis.  

PubMed

The influence of flowing blood on temperatures reached in nearby tumor cells during localized radiofrequency (RF) hyperthermia may be critical for tumor cell survival. We have investigated the effect on the temperatures nearby of blood flowing in a vessel. Using 13.56 MHz capacitive RF, we heated gel phantoms containing a tube through which cooling solution could flow. Our results demonstrated a reduction in temperature of the order of 3 degrees C around the tube when coolant was flowing, and the cooling pattern correlated with theoretical mathematical predictions. Up to 564 joules per minute could be removed from the system. Our results suggest the improbability of uniform tumor cell killing by RF heating. A scheme for integrating the concepts of physical cell damage, biochemical cell damage and peripheral cell survival in a tumor nodule is presented. PMID:4019554

Glazebrook, G A; Jackson, F I; Usiskin, S R

1985-06-01

278

Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets  

SciTech Connect

We report on an experiment irradiating individual argon droplets of 20 {mu}m diameter with laser pulses of several Joule energy at intensities of 10{sup 19} W/cm{sup 2}. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.

Neumayer, P.; Gumberidze, A.; Hochhaus, D. C. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, 60438 Frankfurt am Main (Germany); Aurand, B.; Stoehlker, T. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Costa Fraga, R. A.; Kalinin, A. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Ecker, B. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Kaluza, M. C. [Helmholtz Institute Jena, 07743 Jena (Germany); IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Kuehl, T. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Polz, J. [IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Reuschl, R. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Winters, D.; Winters, N.; Yin, Z. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany)

2012-12-15

279

Corrosive resistant heat exchanger  

Microsoft Academic Search

A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is

Richlen; Scott L

1989-01-01

280

Heat exchanger  

SciTech Connect

A heat exchanger having primary and secondary conduits in heat-exchanging relationship is described comprising: at least one serpentine tube having parallel sections connected by reverse bends, the serpentine tube constituting one of the conduits; a group of open-ended tubes disposed adjacent to the parallel sections, the open-ended tubes constituting the other of the conduits, and forming a continuous mass of contacting tubes extending between and surrounding the serpentine tube sections; and means securing the mass of tubes together to form a predetermined cross-section of the entirety of the mass of open-ended tubes and tube sections.

Drury, C.R.

1988-02-02

281

Temperature Control at DBS Electrodes using Heat Sink: Experimentally Validated FEM Model of DBS lead Architecture  

PubMed Central

There is a growing interest in the use of Deep Brain Stimulation for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. The extent of temperature increases around DBS electrodes during normal operation (joule heating and increased metabolic activity) or coupling with an external source (e.g. MRI) remains poorly understood and methods to mitigate temperature increases are being actively investigated. We developed a heat transfer finite element method simulation of DBS incorporating the realistic architecture of Medtronic 3389 leads. The temperature changes were analyzed considering different electrode configurations, stimulation protocols, and tissue properties. The heat-transfer model results were then validated using micro-thermocouple measurements during DBS lead stimulation in a saline bath. FEM results indicate that lead design (materials and geometry) may have a central role in controlling temperature rise by conducting heat. We show how modifying lead design can effectively control temperature increases. The robustness of this heat-sink approach over complimentary heat-mitigation technologies follows from several features: 1) it is insensitive to the mechanisms of heating (e.g. nature of magnetic coupling); 2) does not interfere with device efficacy; and 3) can be practically implemented in a broad range of implanted devices without modifying the normal device operations or the implant procedure. PMID:22764359

Elwassif, Maged M.; Datta, Abhishek; Rahman, Asif; Bikson, Marom

2012-01-01

282

Bayonet heat exchangers in heat-assisted Stirling heat pump  

SciTech Connect

The Multi-Temperature Heat Supply System is a research project creating a city energy system with lower environmental load. This system consists of a gas-fueled internal combustion engine and a heat-assisted Stirling heat pump utilizing shaft power and thermal power in a combination of several cylinders. The heat pump is mainly driven by engine shaft power and is partially assisted by thermal power from engine exhaust heat source. Since this heat pump is operated by proportioning the two energy sources to match the characteristics of the driving engine, the system is expected to produce cooling and heating water at high COP. This paper describes heat exchanger development in the project to develop a heat-assisted Stirling heat pump. The heat pump employs the Bayonet type heat exchangers (BHX Type I) for supplying cold and hot water and (BHX Type II) for absorbing exhaust heat from the driving engine. The heat exchanger design concepts are presented and their heat transfer and flow loss characteristics in oscillating gas flow are investigated. The main concern in the BHX Type I is an improvement of gas side heat transfer and the spirally finned tubes were applied to gas side of the heat exchanger. For the BHX Type II, internal heat transfer characteristics are the main concern. Shell-and-tube type heat exchangers are widely used in Stirling machines. However, since brazing is applied to the many tubes for their manufacturing processes, it is very difficult to change flow passages to optimize heat transfer and loss characteristics once they have been made. The challenge was to enhance heat transfer on the gas side to make a highly efficient heat exchanger with fewer parts. It is shown that the Bayonet type heat exchanger can have good performance comparable to conventional heat exchangers.

Yagyu, S.; Fukuyama, Y.; Morikawa, T.; Isshiki, N.; Satoh, I.; Corey, J.; Fellows, C.

1998-07-01

283

A General Coupled Mathematical Model of Electromagnetic Phenomena, Two-Phase Flow, and Heat Transfer in Electroslag Remelting Process Including Conducting in the Mold  

NASA Astrophysics Data System (ADS)

A transient three-dimensional finite-volume mathematical model has been developed to investigate the coupled physical fields in the electroslag remelting (ESR) process. Through equations solved by the electrical potential method, the electric current, electromagnetic force (EMF), and Joule heating fields are demonstrated. The mold is assumed to be conductive rather than insulated. The volume of fluid approach is implemented for the two-phase flow. Moreover, the EMF and Joule heating, which are the source terms of the momentum and energy sources, are recalculated at each iteration as a function of the phase distribution. The solidification is modeled by an enthalpy-porosity formulation, in which the mushy zone is treated as a porous medium with porosity equal to the liquid fraction. An innovative marking method of the metal pool profile is proposed in the experiment. The effect of the applied current on the ESR process is understood by the model. Good agreement is obtained between the experiment and calculation. The electric current flows to the mold lateral wall especially in the slag layer. A large amount of Joule heating around the metal droplet varies as it falls. The hottest region appears under the outer radius of the electrode tip, close to the slag/metal interface instead of the electrode tip. The metal pool becomes deeper with more power. The maximal temperature increases from 1951 K to 2015 K (1678 °C to 1742 °C), and the maximum metal pool depth increases from 34.0 to 59.5 mm with the applied current ranging from 1000 to 2000 A.

Wang, Qiang; He, Zhu; Li, Baokuan; Tsukihashi, Fumitaka

2014-12-01

284

Waste heat greenhouse heating system design  

Microsoft Academic Search

A design philosophy for waste heat greenhouse heating systems is presented. The use of detailed computer models for estimating greenhouse heating needs is discussed. Methods of reducing the heat delivery and utilization system capital investment required for a waste heat greenhouse development are given. 16 refs.

D. M. Stipanuk; R. E. Friday

1981-01-01

285

Geothermal heating  

SciTech Connect

The aim of the study is to demonstrate the viability of geothermal heating projects in energy and economic terms and to provide nomograms from which an initial estimate may be made without having to use data-processing facilities. The effect of flow rate and temperature of the geothermal water on drilling and on the network, and the effect of climate on the type of housing are considered.

Aureille, M.

1982-01-01

286

Heat Transfer  

NSDL National Science Digital Library

In this inquiry activity students explore how heat transfers from one substance to another This inquiry activity was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2006 Frontiers in Physiology Program. The NSES Standards addressed by this activity are current as of the year of development. For more information on the Frontiers in Physiology Program, please visit www.frontiersinphys.org.

Ms. Leslie Van (Montgomery Blair High School)

2006-04-01

287

Electron Heating and the Farley-Buneman Instability in the Solar Chromosphere  

NASA Astrophysics Data System (ADS)

Convective motion in the solar chromosphere has generally more than enough energy to po-tentially explain observed heating, but the possible dissipation mechanisms disserve more con-sideration. When, driven by electric fields, neutrals and ions move at different fluid velocities, like it happens in the Earth's thermosphere, then ion-neutral collisions cause friction and Joule heating. Because of a relatively short neutral-ion collision time in the chromosphere, neutral motion is expected to follow the ions within less than a tenth of a second, canceling any elec-tric fields in the reference frame of the neutral gas. Thus only overshooting slip motion from Alfven waves with correspondigly high frequencies can cause frictional heating. In the Earth's lower thermosphere another mechanism, the Farley-Buneman instability, causes quite intense electron heating when the ExB velocity exceeds the ion-acoustic speed. Similar conditions can occur in the chromosphere as well, but again only due to overshooting motion. We have mod-eled electron heating from the Farley-Buneman instability in the chromosphere, assuming that the instability heats similar as in the Earth's ionosphere, but electrons are cooled by collisions with H atoms instead of atmospheric molecules. Then electron temperatures can become very high and the enhancements are eventually limited by radiative losses. Observed ubiquitous and persistent UV emission of the solar chromosphere could so be explained by the Farley-Buneman instability, if the emissions in reality are intermittent with time scales less than a second.

Buchert, Stephan

288

Analysis on heat loss characteristics of a 10 kV HTS power substation  

NASA Astrophysics Data System (ADS)

A 10 kV High Temperature Superconducting power substation (10 kV HTS substation), supported by Chinese State 863 projects, was developed and has been running to supply power for several factories for more than two years at an industrial park of Baiyin, Gansu province in Northwest China. The system of the 10 kV HTS substation compositions, including a HTS cable, a HTS transformer, a SFCL, and a SMES, are introduced. The SMES works at liquid helium temperature and the other three apparatus operates under liquid nitrogen condition. There are mainly four types of heat losses existing in each HTS apparatus of the 10 kV HTS substation, including AC loss, Joule heat loss, conductive heat, and leak-in heat from cryostat. A small quantity of AC loss still exists due to the harmonic component of the current when it carries DC for HTS apparatus. The principle and basis for analysis of the heat losses are introduced and the total heat loss of each apparatus are calculated or estimated, which agree well with the test result. The analysis and result presented are of importance for the design of the refrigeration system.

Teng, Yuping; Dai, Shaotao; Song, Naihao; Zhang, Jingye; Gao, Zhiyuan; Zhu, Zhiqin; Zhou, Weiwei; Wei, Zhourong; Lin, Liangzhen; Xiao, Liye

2014-09-01

289

Heat pump system  

DOEpatents

An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. 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 heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaurn, FL)

1982-01-01

290

Waste Heat Recovery from High Temperature Off-Gases from Electric Arc Furnace  

SciTech Connect

This article presents a study and review of available waste heat in high temperature Electric Arc Furnace (EAF) off gases and heat recovery techniques/methods from these gases. It gives details of the quality and quantity of the sensible and chemical waste heat in typical EAF off gases, energy savings potential by recovering part of this heat, a comprehensive review of currently used waste heat recovery methods and potential for use of advanced designs to achieve a much higher level of heat recovery including scrap preheating, steam production and electric power generation. Based on our preliminary analysis, currently, for all electric arc furnaces used in the US steel industry, the energy savings potential is equivalent to approximately 31 trillion Btu per year or 32.7 peta Joules per year (approximately $182 million US dollars/year). This article describes the EAF off-gas enthalpy model developed at Oak Ridge National Laboratory (ORNL) to calculate available and recoverable heat energy for a given stream of exhaust gases coming out of one or multiple EAF furnaces. This Excel based model calculates sensible and chemical enthalpy of the EAF off-gases during tap to tap time accounting for variation in quantity and quality of off gases. The model can be used to estimate energy saved through scrap preheating and other possible uses such as steam generation and electric power generation using off gas waste heat. This article includes a review of the historical development of existing waste heat recovery methods, their operations, and advantages/limitations of these methods. This paper also describes a program to develop and test advanced concepts for scrap preheating, steam production and electricity generation through use of waste heat recovery from the chemical and sensible heat contained in the EAF off gases with addition of minimum amount of dilution or cooling air upstream of pollution control equipment such as bag houses.

Nimbalkar, Sachin U [ORNL; Thekdi, Arvind [E3M Inc; Keiser, James R [ORNL; Storey, John Morse [ORNL

2014-01-01

291

On Variations of Space-heating Energy Use in Office Buildings  

SciTech Connect

Space heating is the largest energy end use, consuming more than 7 quintillion joules of site energy annually in the U.S. building sector. A few recent studies showed discrepancies in simulated space-heating energy use among different building energy modeling programs, and the simulated results are suspected to be underpredicting reality. While various uncertainties are associated with building simulations, especially when simulations are performed by different modelers using different simulation programs for buildings with different configurations, it is crucial to identify and evaluate key driving factors to space-heating energy use in order to support the design and operation of low-energy buildings. In this study, 10 design and operation parameters for space-heating systems of two prototypical office buildings in each of three U.S. heating climates are identified and evaluated, using building simulations with EnergyPlus, to determine the most influential parameters and their impacts on variations of space-heating energy use. The influence of annual weather change on space-heating energy is also investigated using 30-year actual weather data. The simulated space-heating energy use is further benchmarked against those from similar actual office buildings in two U.S. commercial-building databases to better understand the discrepancies between simulated and actual energy use. In summary, variations of both the simulated and actual space-heating energy use of office buildings in all three heating climates can be very large. However these variations are mostly driven by a few influential parameters related to building design and operation. The findings provide insights for building designers, owners, operators, and energy policy makers to make better decisions on energy-efficiency technologies to reduce space-heating energy use for both new and existing buildings.

Lin, Hung-Wen; Hong, Tianzhen

2013-05-01

292

Water and Space Heating Heat Pumps  

E-print Network

fossil fired heating units or electric resistance water heaters. When electric resistance water heaters are utilized there are three alternative electric heating concepts available to reduce home energy consumption. They are desuperheaters, dedicated heat...

Kessler, A. F.

1985-01-01

293

Industrial Waste Heat Recovery Using Heat Pipes  

E-print Network

For almost a decade now, heat pipes with secondary finned surfaces have been utilized in counter flow heat exchangers to recover sensible energy from industrial exhaust gases. Over 3,000 such heat exchangers are now in service, recovering...

Ruch, M. A.

1981-01-01

294

Heat pipe heat exchanger design considerations  

Microsoft Academic Search

Typical heat pipe heat exchangers (HPHX) are described, along with their advantages, uses, and some problems in HPHX design, and a computer HPHX analysis program is discussed with required input data. The computer program is being developed for analysis of heat exchange performance by finned-tube HPHX and thread-puddle-artery heat pipes. Copper-water heat pipes and carbon steel-Dowtherm A heat pipes are

K. T. Feldman; D. C. Lu

1976-01-01

295

Heat pipes in modern heat exchangers  

Microsoft Academic Search

Heat pipes are very flexible systems with regard to effective thermal control. They can easily be implemented as heat exchangers inside sorption and vapour-compression heat pumps, refrigerators and other types of heat transfer devices. Their heat transfer coefficient in the evaporator and condenser zones is 103–105 W\\/m2K, heat pipe thermal resistance is 0.01–0.03 K\\/W, therefore leading to smaller area and

Leonard L. Vasiliev

2005-01-01

296

Heat pipe waste heat recovery boilers  

NASA Astrophysics Data System (ADS)

The use of heat pipes as transport devices in waste heat recovery boilers is examined. Test results show that heat pipes can efficiently extract heat from the hot gas stream and transfer it inside the pressure vessel for the steam generation process. The benefits of incorporating heat pipes into the design of waste heat recovery boilers include a highly compact package, a significant reduction in thermally induced stresses, double isolation of the steam from the heat source, an extended surface for improved efficiency in heat extraction, improved circulation and stability in the boiling regime, easy cleaning, individually replaceable tubes, and low flue gas pressure drop.

Littwin, D. A.; McCurley, J.

297

Heating systems for heating subsurface formations  

DOEpatents

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.

Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

2011-04-26

298

Heat exchanger  

NASA Astrophysics Data System (ADS)

A heat exchanger comprising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of the tube sheet is disclosed. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in tube sheet. A tube bundle is mounted within the shell and is provided with inlets and outlets formed in the tube sheet in communication with the first and second chambers, respectively.

Brackenbury, P. J.

1983-12-01

299

Heat exchanger  

DOEpatents

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, Phillip J. (Richland, WA)

1986-01-01

300

Heat exchanger  

DOEpatents

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, P.J.

1983-12-08

301

High temperature heat exchangers  

Microsoft Academic Search

This book contains the proceedings from the XVII Symposium of the International Center for Heat and Mass Transfer on High Temperature Heat Exchangers, held August 1985 in Yugoslavia. Papers were presented under the following topics: High Temperature Heat Exchangers Development; Basic Problem in High Temperature Heat Exchangers; Heat Exchangers for High Temperature Recovery; and High Temperature Heat Exchangers for Future

Y. Mori; A. E. Sheindlin; N. Afgan

1986-01-01

302

Waste Heat Recovery  

Microsoft Academic Search

Investments in waste heat recovery provide a very attractive payback. This article covers cases implemented over the past four years among Shaw's 50 manufacturing plants. Heat sources tapped are air compressors, waste water, boiler stack gasses, and boiler blow down. The destination for the heat is process water heating and boiler make-up water heating. Heat exchangers only have been used,

Jerry T. Zolkowski

2009-01-01

303

ABSORPTION HEAT PUMP IN THE DISTRICT HEATING  

E-print Network

#12;ABSORPTION HEAT PUMP IN THE DISTRICT HEATING PLANT Dr.sc.ing. Agnese Lickrastina M.Sc. Normunds · DHP Imanta ­ combined cycle cogeneration plant , (48 MWel, 48 MWth) in 2006 ­ absorption heat pump Steam Turbine 16 MWel Steam Boiler 12 t/h, 13 bar Absorption HP/Chiller 5 MWth #12;European Heat Pump

Oak Ridge National Laboratory

304

Latent Heat in Soil Heat Flux Measurements  

Technology Transfer Automated Retrieval System (TEKTRAN)

The surface energy balance includes a term for soil heat flux. Soil heat flux is difficult to measure because it includes conduction and convection heat transfer processes. Accurate representation of soil heat flux is an important consideration in many modeling and measurement applications. Yet, the...

305

Heat Rash or Prickly Heat (Miliaria Rubra)  

MedlinePLUS

newsletter | contact Share | Heat Rash or Prickly Heat (Miliaria Rubra) A parent's guide for infants and babies A A A In miliaria rubra, blocked sweat ... bumps. Overview Miliaria rubra, also known as heat rash or prickly heat, is a common skin condition ...

306

Heat recovery method  

SciTech Connect

Heat is recovered by combining a heat transfer system including heat exchangers interconnected in a circulatory system, with a heat pump system. The heat pump system is preferably operated in accordance with the Lorenz-Principle. It is not necessary to divide the heat carrier circuit of the heat pump into two or three separate circulatory circuits. The heat carrier circuit of the heat pump can thus continue to operate unchanged even if the heat pump is switched off. For this purpose the warm heat carrier coming from a discharge fluid cooler, is heated further in a condenser of the heat pump and the cold heat carrier coming from a preheater or cooler group, is cooled further in an evaporator of the heat pump.

Richarts, F.

1985-04-16

307

Dual source heat pump  

DOEpatents

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

Ecker, Amir L. (Dallas, TX); Pietsch, Joseph A. (Dallas, TX)

1982-01-01

308

Segmented heat exchanger  

SciTech Connect

A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

Baldwin, Darryl Dean (Lafayette, IN); Willi, Martin Leo (Dunlap, IL); Fiveland, Scott Byron (Metamara, IL); Timmons, Kristine Ann (Chillicothe, IL)

2010-12-14

309

Dynamic response characteristics of thermoelectric generator predicted by a three-dimensional heat-electricity coupled model  

NASA Astrophysics Data System (ADS)

The practical application environments of thermoelectric generators (TEGs) always change, which make a requirement for studying the dynamic response characteristics of TEGs. This work develops a complete, three-dimensional and transient model to investigate this issue. The model couples the energy and electric potential equations. Seebeck effect, Peltier effect, Thomson effect, Joule heating and Fourier heat conduction are taken into account in this model. Dynamic output power and conversion efficiency of the TEG, which are caused by variations of the hot end temperature, cold end temperature and load current, are studied. The response hysteresis of the output power to the hot end and cold end temperatures, the overshoot or undershoot of the conversion efficiency are found and attributed to the delay of thermal diffusion. However, the output power is synchronous with the load current due to much faster electric response than thermal response.

Meng, Jing-Hui; Zhang, Xin-Xin; Wang, Xiao-Dong

2014-01-01

310

Heat production in the windings of the stators of electric machines under stationary condition  

NASA Astrophysics Data System (ADS)

In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.

Alebouyeh Samami, Behzad; Pieper, Martin; Breitbach, Gerd; Hodapp, Josef

2014-12-01

311

Transient Heat Transport in Subcooled He II Associated with JT Effect  

NASA Astrophysics Data System (ADS)

Transient heat transport in subcooled He II has been investigated in a 1 m long rectangular channel with distributed contractions: one-closed end has a heater, while the other end is open to the He II bath. Experiments were conducted applying heat pulses and recording the temperature profile with seven Allan Bradley resistors placed along the channel. Cernox sensor was indium soldered on the heater surface to monitor the onset of film boiling. As the onset of heat pulse, the pressure at the heater surface increased because of phase change from subcooled He II to He I. Further increasing of heat pulse leads to coexistence of triple-phase, He I vapor layer, He I and subcooled He II, at the vicinity of heater surface. These effects induced instantaneous He II temperature drop along the channel, which is caused by Joule-Thomson (JT) effect. A simple model gives an approximate mechanism of pressure increase in the channel. The paper describes transient heat transport mechanism in the channel and discusses JT effect within the channel.

Maekawa, R.; Iwamoto, A.; Hamaguchi, S.

2004-06-01

312

Heat pump control system  

SciTech Connect

A method is described of controlling a heating system having a supplemental heat source and a heat pump for supplying heat to an interior space. The heating system includes a thermostat mechanism that activates the heat pump and supplemental heat source in response to ambient temperatures in the interior space sensed by the thermostat. The method comprises sensing when the supplemental heat source is operating during a cyclically recurring time interval, and disabling the heat pump when the supplemental heat source is operating for a predetermined portion of the cyclically recurring time interval.

Harshbarger, J.H. III; Harshbarger, J.H. Jr

1986-12-09

313

Temperature control at DBS electrodes using a heat sink: experimentally validated FEM model of DBS lead architecture  

NASA Astrophysics Data System (ADS)

There is a growing interest in the use of deep brain stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. The extent of temperature increases around DBS electrodes during normal operation (joule heating and increased metabolic activity) or coupling with an external source (e.g. magnetic resonance imaging) remains poorly understood and methods to mitigate temperature increases are being actively investigated. We developed a heat transfer finite element method (FEM) simulation of DBS incorporating the realistic architecture of Medtronic 3389 leads. The temperature changes were analyzed considering different electrode configurations, stimulation protocols and tissue properties. The heat-transfer model results were then validated using micro-thermocouple measurements during DBS lead stimulation in a saline bath. FEM results indicate that lead design (materials and geometry) may have a central role in controlling temperature rise by conducting heat. We show how modifying lead design can effectively control temperature increases. The robustness of this heat-sink approach over complimentary heat-mitigation technologies follows from several features: (1) it is insensitive to the mechanisms of heating (e.g. nature of magnetic coupling); (2) it does not interfere with device efficacy; and (3) can be practically implemented in a broad range of implanted devices without modifying the normal device operations or the implant procedure.

Elwassif, Maged M.; Datta, Abhishek; Rahman, Asif; Bikson, Marom

2012-08-01

314

Nonlinear Radiation Heat Transfer Effects in the Natural Convective Boundary Layer Flow of Nanofluid Past a Vertical Plate: A Numerical Study  

PubMed Central

The problem of natural convective boundary layer flow of nanofluid past a vertical plate is discussed in the presence of nonlinear radiative heat flux. The effects of magnetic field, Joule heating and viscous dissipation are also taken into consideration. The governing partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations via similarity transformations and then solved numerically using the Runge–Kutta fourth-fifth order method with shooting technique. The results reveal an existence of point of inflection for the temperature distribution for sufficiently large wall to ambient temperature ratio. Temperature and thermal boundary layer thickness increase as Brownian motion and thermophoretic effects intensify. Moreover temperature increases and heat transfer from the plate decreases with an increase in the radiation parameter. PMID:25251242

Mustafa, Meraj; Mushtaq, Ammar; Hayat, Tasawar; Ahmad, Bashir

2014-01-01

315

Integrated Heat Pump (IHP) System Development - Air-Source IHP Control Strategy and Specifications and Ground-Source IHP Conceptual Design  

SciTech Connect

The integrated heat pump (IHP), as one appliance, can provide space cooling, heating, ventilation, and dehumidification while maintaining comfort and meeting domestic water heating needs in near-zero-energy home (NZEH) applications. In FY 2006 Oak Ridge National Laboratory (ORNL) completed development of a control strategy and system specification for an air-source IHP. The conceptual design of a ground-source IHP was also completed. Testing and analysis confirm the potential of both IHP concepts to meet NZEH energy services needs while consuming 50% less energy than a suite of equipment that meets current minimum efficiency requirements. This report is in fulfillment of an FY06 DOE Building Technologies (BT) Joule Milestone.

Murphy, Richard W [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

2007-05-01

316

Nonlinear radiation heat transfer effects in the natural convective boundary layer flow of nanofluid past a vertical plate: a numerical study.  

PubMed

The problem of natural convective boundary layer flow of nanofluid past a vertical plate is discussed in the presence of nonlinear radiative heat flux. The effects of magnetic field, Joule heating and viscous dissipation are also taken into consideration. The governing partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations via similarity transformations and then solved numerically using the Runge-Kutta fourth-fifth order method with shooting technique. The results reveal an existence of point of inflection for the temperature distribution for sufficiently large wall to ambient temperature ratio. Temperature and thermal boundary layer thickness increase as Brownian motion and thermophoretic effects intensify. Moreover temperature increases and heat transfer from the plate decreases with an increase in the radiation parameter. PMID:25251242

Mustafa, Meraj; Mushtaq, Ammar; Hayat, Tasawar; Ahmad, Bashir

2014-01-01

317

Direct observation of resistive heating at graphene wrinkles and grain boundaries  

SciTech Connect

We directly measure the nanometer-scale temperature rise at wrinkles and grain boundaries (GBs) in functioning graphene devices by scanning Joule expansion microscopy with 50 nm spatial and 0.2K temperature resolution. We observe a small temperature increase at select wrinkles and a large (100 K) temperature increase at GBs between coalesced hexagonal grains. Comparisons of measurements with device simulations estimate the GB resistivity (8 150 X lm) among the lowest reported for graphene grown by chemical vapor deposition. An analytical model is developed, showing that GBs can experience highly localized resistive heating and temperature rise, most likely affecting the reliability of graphene devices. Our studies provide an unprecedented view of thermal effects surrounding nanoscale defects in nanomaterials such as graphene.

Grosse, Kyle L. [University of Illinois Urbana-Champaign; Dorgan, Vincent E. [University of Illinois at Urbana-Champaign, Urbana-Champaign; Estrada, David [University of Illinois at Urbana-Champaign, Urbana-Champaign; Wood, Joshua D. [University of Illinois at Urbana-Champaign, Urbana-Champaign; Vlassiouk, Ivan V [ORNL; Eres, Gyula [ORNL; Lyding, Joseph W [University of Illinois at Urbana-Champaign, Urbana-Champaign; King, William P. [University of Illinois at Urbana-Champaign, Urbana-Champaign; Pop, Eric [Stanford University

2014-01-01

318

On the mechanism of particle heating and acceleration in the Jovian ionosphere  

NASA Astrophysics Data System (ADS)

The acceleration mechanism of the charged particles connected with a potential difference along the Jovian magnetic field is proposed. This model is developed on the basis of the known phenomenon of the partially ionized magnetized plasma resistance increase in the presence of a nonstationary current. The region of high resistance is formed above the ionosphere plasma density maximum when the Io current tube is going through this region. For typical Jovian ionosphere conditions the resistance is increased by about seven orders. The potential difference accelerates particles up to several MeV in this region. Here, we also take into account that the efficiency of electron acceleration is limited by the Bunneman turbulence excited due to an electron-ion relative motion. The plasma is heated due to the Joule dissipation and the Bunneman turbulence by several orders of keV.

Shaposhnikov, V. E.; Zaitsev, V. V.

1993-05-01

319

Heating Up  

NSDL National Science Digital Library

This interactive, online activity introduces the idea that everything emits electromagnetic radiation, including students. Students discover how the light emitted from an object (a robot) changes as the object is heated. A graph shows the amount of light the robot emits in each wavelength region as the robot reaches higher temperatures. Students are challenged to relate the peak of the emitted light from the robot to the color it appears, thus connecting the temperature of an object with the color of light it emits. Students apply this information by plotting the peak wavelengths of four stars of their choice, and then determine the temperature of each. Upon completion of this activity, students will have identified peak wavelengths from graphical data and applied this concept to determine the relationship between temperature and star color. Students may complete this activity independently or in small groups. Detailed teacher pages, identified as Teaching Tips on the title page of the activity, provide science background information, lesson plan ideas, related resources, and alignment with national education standards. This activity is part of the online exploration "Star Light, Star Bright" that focuses on the electromagnetic spectrum and that is available on the Amazing Space website.

320

Multiple source heat pump  

DOEpatents

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.

Ecker, Amir L. (Duncanville, TX)

1983-01-01

321

Industrial heat exchangers  

Microsoft Academic Search

This book presents the papers given at a symposium on the use of heat exchangers in the industrial plants. Topics considered include the US DOE and GRI research programs, advanced fixed boundary heat exchanger technology, commercial heat exchanger applications, thermo-hydraulic performance of heat-transfer equipment, field tests, the corrosion of heat exchanger materials, economics, cost benefit analysis, payback, and advanced assembly

A. J. Hayes; W. W. Liang; S. L. Richlen; E. S. Tabb

1985-01-01

322

Flue heat recovery system  

Microsoft Academic Search

A flue gas heat recovery system is disclosed comprising an exhaust gas to air heat exchanger, a hot air to water heat exchanger, a fan, a circulating pump, and a control system which senses the temperature of the exiting air from the air heat exchanger and the temperature of the water leaving the water heat exchanger in combination with the

Henriques

1983-01-01

323

The LUCIA project: towards 100 joules nanosecond pulses, kW averaged power, based on ytterbium diode pumped solid state laser  

Microsoft Academic Search

Summary form only given. We show that diode pumped Yb:YAG lasers are particularly good candidates for femtosecond pulse applications, because centimeter-scale size aperture YAG crystals are easily available, their heat generation is reduced relative to Nd:YAG and high power laser diodes are available at the required pump wavelength. We designed the LUCIA laser system to consist of: an oscillator delivering

J.-C. Chanteloup; G. Bourdet; A. Migus

2002-01-01

324

Energy Corner: Heat Reclamation Rescues Wasted Heat.  

ERIC Educational Resources Information Center

Heat reclamation systems added to pre-existing central heating systems provide maximum savings at minimum cost. The benefits of a particular appliance marketed under the brand name "Energizer" are discussed. (Author/MLF)

Daugherty, Thomas

1982-01-01

325

Critical heat flux around strongly heated nanoparticles  

NASA Astrophysics Data System (ADS)

We study heat transfer from a heated nanoparticle into surrounding fluid using molecular dynamics simulations. We show that the fluid next to the nanoparticle can be heated well above its boiling point without a phase change. Under increasing nanoparticle temperature, the heat flux saturates, which is in sharp contrast with the case of flat interfaces, where a critical heat flux is observed followed by development of a vapor layer and heat flux drop. These differences in heat transfer are explained by the curvature-induced pressure close to the nanoparticle, which inhibits boiling. When the nanoparticle temperature is much larger than the critical fluid temperature, a very large temperature gradient develops, resulting in close to ambient temperature just a radius away from the particle surface. The behavior reported allows us to interpret recent experiments where nanoparticles can be heated up to the melting point, without observing boiling of the surrounding liquid.

Merabia, Samy; Keblinski, Pawel; Joly, Laurent; Lewis, Laurent J.; Barrat, Jean-Louis

2009-02-01

326

Operation of an ADR using helium exchange gas as a substitute for a failed heat switch  

NASA Astrophysics Data System (ADS)

The Soft X-ray Spectrometer (SXS) is one of four instruments on the Japanese Astro-H mission, which is currently planned for launch in late 2015. The SXS will perform imaging spectroscopy in the soft X-ray band (0.3-12 keV) using a 6 × 6 pixel array of microcalorimeters cooled to 50 mK. The detectors are cooled by a 3-stage adiabatic demagnetization refrigerator (ADR) that rejects heat to either a superfluid helium tank (at 1.2 K) or to a 4.5 K Joule-Thomson (JT) cryocooler. Four gas-gap heat switches are used in the assembly to manage heat flow between the ADR stages and the heat sinks. The engineering model (EM) ADR was assembled and performance tested at NASA/GSFC in November 2011, and subsequently installed in the EM dewar at Sumitomo Heavy Industries, Japan. During the first cooldown in July 2012, a failure of the heat switch that linked the two colder stages of the ADR to the helium tank was observed. Operation of the ADR requires some mechanism for thermally linking the salt pills to the heat sink, and then thermally isolating them. With the failed heat switch unable to perform this function, an alternate plan was devised which used carefully controlled amounts of exchange gas in the dewar's guard vacuum to facilitate heat exchange. The process was successfully demonstrated in November 2012, allowing the ADR to cool the detectors to 50 mK for hold times in excess of 10 h. This paper describes the exchange-gas-assisted recycling process, and the strategies used to avoid helium contamination of the detectors at low temperature.

Shirron, P.; DiPirro, M.; Kimball, M.; Sneiderman, G.; Porter, F. S.; Kilbourne, C.; Kelley, R.; Fujimoto, R.; Yoshida, S.; Takei, Y.; Mitsuda, K.

2014-11-01

327

Numerical Analysis of Heat Transfer and Fluid Characteristics of Flowing Liquid Nitrogen in HTS Cable  

NASA Astrophysics Data System (ADS)

High-temperature superconducting (HTS) cable has heat intrusion from the termination including joule heat generation at the terminal joint and from the room temperature cable through the Cu current lead. According to the length of the HTS cable, this heat loss may become a considerable amount which cannot be ignored in the HTS cable system. In this study, referring to a high-voltage cable (HV cable) which was developed in M-PACC project, the effect of heat transfer at the interface between the terminal joint and LN2 in the terminal vessel (ho) on the temperature of the HTS cable were calculated and evaluated. The condition of flow in the terminal vessel was assumed to be natural convection, forced flow or static condition for evaluating this effect with various heat transfer condition. As a result, in the case of the natural convection, most of heats flow into the LN2 in the terminal vessel where the volumetric flow of the LN2 is large since ho becomes high. Accordingly, the temperature rise of the LN2 in the inner pipe of Cu former and the terminal vessel can be restricted. However, in the cases of the forced flow and the static condition, most of heats flow into the LN2 in the inner pipe where the volumetric flow of the LN2 is small since ho becomes small. Accordingly, the temperature rise of the LN2 in the inner pipe becomes high. This temperature rise of the LN2 in the inner pipe makes the temperature of the HTS conductor large resulting in remarkable increase of AC losses. Consequently, on the HV cable design, for restriction of the AC loss increase, it is expected that designing the HTS cable termination such as extending outer surface of the terminal joint for increasing of the heat inflow from the terminal joint to the LN2 in the vessel is effective.

Maruyama, O.; Ohkuma, T.; Izumi, T.; Shiohara, Y.

328

Development of Rapid Pipe Moulding Process for Carbon Fiber Reinforced Thermoplastics by Direct Resistance Heating  

NASA Astrophysics Data System (ADS)

To deal with environmental issues, the gasoline mileage of passenger cars can be improved by reduction of the car weight. The use of car components made of Carbon Fiber Reinforced Plastics (CFRP) is increasing because of its superior mechanical properties and relatively low density. Many vehicle structural parts are pipe-shaped, such as suspension arms, torsion beams, door guard bars and impact beams. A reduction of the car weight is expected by using CFRP for these parts. Especially, when considering the recyclability and ease of production, Carbon Fiber Reinforced Thermoplastics are a prime candidate. On the other hand, the moulding process of CFRTP pipes for mass production has not been well established yet. For this pipe moulding process an induction heating method has been investigated already, however, this method requires a complicated coil system. To reduce the production cost, another system without such complicated equipment is to be developed. In this study, the pipe moulding process of CFRTP using direct resistance heating was developed. This heating method heats up the mould by Joule heating using skin effect of high-frequency current. The direct resistance heating method is desirable from a cost perspective, because this method can heat the mould directly without using any coils. Formerly developed Non-woven Stitched Multi-axial Cloth (NSMC) was used as semi-product material. NSMC is very suitable for the lamination process due to the fact that non-crimp stitched carbon fiber of [0°/+45°/90°/-45°] and polyamide 6 non-woven fabric are stitched to one sheet, resulting in a short production cycle time. The use of the pipe moulding process with the direct resistance heating method in combination with the NSMC, has resulted in the successful moulding of a CFRTP pipe of 300 mm in length, 40 mm in diameter and 2 mm in thickness.

Tanaka, Kazuto; Harada, Ryuki; Uemura, Toshiki; Katayama, Tsutao; Kuwahara, Hideyuki

329

Natural convection heat transfer on surfaces of copper micro-wires  

NASA Astrophysics Data System (ADS)

The natural convection heat transfer characteristics and mechanism for copper micro-wires in water and air were investigated experimentally and numerically. The wires with diameters of 39.9, 65.8 and 119.1 ?m were placed horizontally in water inside of a sealed tube and in air of a large room, respectively. Using Joule heating, the heat transfer coefficients and Nusselt numbers of natural convection for micro-wires in ultra pure water and air were obtained. A three dimensional incompressible numerical model was used to investigate the natural convection, and the prediction with this model was in reasonable accordance with the experimental results. With the decrease of micro-wire diameter, the heat transfer coefficient of natural convection on the surface of micro-wire becomes larger, while the Nu number of natural convection decreases in water and air. Besides, the change rate of Nu number in water decreases apparently with the increase of heat flux and the decrease of wire diameter, which is larger than that in air. The thickness of boundary layer on the wall of micro-wire becomes thinner with the decrease of diameter in both water and air, but the ratio of boundary layer thickness in water to the diameter increases. However, there is almost no change of this ratio for natural convection in air. As a result, the proportion of conduction in total heat transfer of natural convection in water increases, while the convective heat transfer decreases. The velocity distribution, temperature field and the boundary layer in the natural convection were compared with those of tube with conventional dimension. It was found that the boundary layer around the micro-wire is an oval-shaped film on the surface, which was different from that around the conventional tube. This apparently reduces the convection strength in the natural convection, thus the heat transfer presents a conduction characteristic.

Guan, Ning; Liu, Zhigang; Zhang, Chengwu; Jiang, Guilin

2014-02-01

330

Absorption heat pump system  

DOEpatents

The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

Grossman, Gershon (Oak Ridge, TN)

1984-01-01

331

Locating Heat Recovery Opportunities  

E-print Network

Basic concepts of heat recovery are defined as they apply to the industrial community. Methods for locating, ranking, and developing heat recovery opportunities are presented and explained. The needs for useful heat 'sinks' are emphasized as equal...

Waterland, A. F.

1981-01-01

332

Steady response to heating: Gaussian heat source  

E-print Network

#12;Equatorial Waves Alternative theory for wave speed: ¡ Higher vertical mode structure causes phaseGill Model Steady response to heating: Gaussian heat source in center of domain. Boundary: Heating applied in region A. Only subsidence contours are drawn (there is upward motion elsewhere). From

Frierson, Dargan

333

Acceleration of solar wind in polar coronal holes by induction heating  

NASA Technical Reports Server (NTRS)

The universal induction heating mechanism supplying with the energy all the processes of coronal heating and the solar wind acceleration is developed. The observed relative 'trembling' of photospheric super-large scale magnetic fields with quasi-periods of 1-4 days amounts 30-40 percent in amplitude. The inductive electric field appears in the corona. The electric currents cause the Joule dissipation. The uneven heating leads to the solar wind acceleration. A model is suggested in which high-speed streams in space are caused by the combination of the enhanced inductive energy flux from the solar coronal active regions; the work against the regular magnetic field; losses from coronal emission. The consideration is made in terms of the dissipative solar wind theory with the finite electrical conductivity of plasma. The leakage of plasma and the energy flux across the magnetic field, caused by the induction heating processes, are taken into account. The polar coronal holes (and the mid-latitude ones) are indicators of energy transfer balance but not direct sources of high-speed streams in the solar wind.

Chertkov, A. D.; Shkrebets, A. E.; Arkhipov, Yu. V.; Soldatov, V. A.

1995-01-01

334

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

SciTech Connect

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

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

2014-06-01

335

Probing fast heating in magnetic tunnel junction structures with exchange bias  

NASA Astrophysics Data System (ADS)

Heat diffusion in a magnetic tunnel junction (MTJ) having a ferromagnetic/antiferromagnetic free layer is investigated. The MTJ is heated by an electric current pulse of power PHP, flowing through the junction in current perpendicular to the plane (CPP) geometry, via Joule heat dissipation in the tunnel barrier. According to a proposed one-dimensional (1D) model of heat diffusion, when an electric voltage is applied to the MTJ, the free layer experiences a transient temperature regime, characterized by an exponential increase of its temperature TAF with a time constant ?TR, followed by a steady temperature regime characterized by TAF=TRT+?PHP, where TRT is the room temperature and ? is a constant. Magnetic transport measurements of exchange bias HEX acting on the free layer allow the determination of ? and ?TR. The experimental values of ? and ?TR are in agreement with those calculated using the 1D model and an estimation of the MTJ thermodynamic parameters based on the Dulong Petit and Widemann Franz laws.

Papusoi, C.; Sousa, R.; Herault, J.; Prejbeanu, I. L.; Dieny, B.

2008-10-01

336

Woven heat exchanger  

DOEpatents

This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Piscitella, R.R.

1984-07-16

337

High Temperature Heat Recovery Systems Using Ceramic Recuperators  

E-print Network

industry practice, require on average at least 3.000 Btu per lb. (6.98 x 10 6 joules per kg.) to bring car~on steel to forging tem perature. Most furnaces actually use at least 4.000 Btu/lb. (9.3 x 10 6 joules per kg.). Hague's high performance... furnaces, in commercial operation since the summer of 1979, have demonstrated their ability to bring steel to forging temperature at rates of 1000 Btu/lb (2.33 x 10 6 joules per kg.) and less. 5.0 INSTALLATION HISTORY 5.1 Retrofi t Packages The first...

Young, S. B.; Bjerklie, J. W.; York, W. A.

1980-01-01

338

Heat transport and solidification in the electromagnetic casting of aluminum alloys. Part 2: Development of a mathematical model and comparison with experimental results  

SciTech Connect

In this second article of a two-part series, a mathematical model for heat transport and solidification of aluminum in electromagnetic casting is developed. The model is a three-dimensional one but involves a simplified treatment of convective heat transport in the liquid metal pool. Heat conduction in the solid was thought to play a dominant role in heat transport, and the thermal properties of the two alloys used in measurements reported in Part 1 (AA 5182 and 3104) were measured independently for input to the model. Heat transfer into the water sprays impacting the sides of the ingot was approximated using a heat-transfer coefficient from direct chill casting; because this heat-transfer step appears not to be rate determining for solidification and cooling of most of the ingot, there is little inaccuracy involved in this approximation. Joule heating was incorporated into some of the computations, which were carried out using the finite element software FIDAP. There was good agreement between the computed results and extensive thermocouple measurements (reported in Part 1) made on a pilot-scale caster at Reynolds Metals Company (Richmond, VA).

Prasso, D.C. [Intel Corp., Aloha, OR (United States); Evans, J.W. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; Wilson, I.J. [Reynolds Metals Co., Muscle Shoals, AL (United States)

1995-12-01

339

A Study of Alfven Wave Propagation and Heating the Chromosphere  

NASA Astrophysics Data System (ADS)

Alfven wave propagation, reflection and heating of the solar atmosphere are studied for a one-dimensional solar atmosphere by self-consistently solving plasma and neutral fluid equations and Maxwell's equations with incorporation of the Hall effect, strong electron-neutral, electron-ion, and ion-neutral collisions. The governing equations are very stiff because of the strong coupling between the charged and neutral fluids. We have developed a numerical model based on an implicit backward difference formula (BDF2) of second order accuracy both in time and space to overcome the stiffness. A non-reflecting boundary condition is applied to the top boundary of the simulation domain so that the wave reflection within the domain due to the density gradient can be unambiguously determined. It is shown that the Alfven waves are partially reflected throughout the chromosphere. The reflection is increasingly stronger at higher altitudes and the strongest reflection occurs at the transition region. The waves are damped in the lower chromosphere dominantly through Joule dissipation due to electron collisions with neutrals and ions. The heating resulting from the wave damping is strong enough to balance the radiation energy loss for the quiet chromosphere. The collisional dissipation of the Alfven waves in the weakly collisional corona is negligible. The heating rates are larger for weaker background magnetic fields. In addition, higher frequency waves are subject to heavier damping. There is an upper cutoff frequency, depending on the background magnetic field, above which the waves are completely damped. At the frequencies below which the waves are not strongly damped, the waves may be strongly reflected at the transition region. The reflected waves interacting with the upward propagating waves may produce power at their double frequencies, which leads to more damping. Due to the reflection and damping, the energy flux of the waves transmitted to the corona is one order of magnitude smaller than that of the driving source.

Tu, J.; Song, P.

2013-12-01

340

A Study of Alfvén Wave Propagation and Heating the Chromosphere  

NASA Astrophysics Data System (ADS)

Alfvén wave propagation, reflection, and heating of the chromosphere are studied for a one-dimensional solar atmosphere by self-consistently solving plasma, neutral fluid, and Maxwell's equations with incorporation of the Hall effect and strong electron-neutral, electron-ion, and ion-neutral collisions. We have developed a numerical model based on an implicit backward difference formula of second-order accuracy both in time and space to solve stiff governing equations resulting from strong inter-species collisions. A non-reflecting boundary condition is applied to the top boundary so that the wave reflection within the simulation domain can be unambiguously determined. It is shown that due to the density gradient the Alfvén waves are partially reflected throughout the chromosphere and more strongly at higher altitudes with the strongest reflection at the transition region. The waves are damped in the lower chromosphere dominantly through Joule dissipation, producing heating strong enough to balance the radiative loss for the quiet chromosphere without invoking anomalous processes or turbulences. The heating rates are larger for weaker background magnetic fields below ~500 km with higher-frequency waves subject to heavier damping. There is an upper cutoff frequency, depending on the background magnetic field, above which the waves are completely damped. At the frequencies below which the waves are not strongly damped, the interaction of reflected waves with the upward propagating waves produces power at their double frequencies, which leads to more damping. The wave energy flux transmitted to the corona is one order of magnitude smaller than that of the driving source.

Tu, Jiannan; Song, Paul

2013-11-01

341

A STUDY OF ALFVÉN WAVE PROPAGATION AND HEATING THE CHROMOSPHERE  

SciTech Connect

Alfvén wave propagation, reflection, and heating of the chromosphere are studied for a one-dimensional solar atmosphere by self-consistently solving plasma, neutral fluid, and Maxwell's equations with incorporation of the Hall effect and strong electron-neutral, electron-ion, and ion-neutral collisions. We have developed a numerical model based on an implicit backward difference formula of second-order accuracy both in time and space to solve stiff governing equations resulting from strong inter-species collisions. A non-reflecting boundary condition is applied to the top boundary so that the wave reflection within the simulation domain can be unambiguously determined. It is shown that due to the density gradient the Alfvén waves are partially reflected throughout the chromosphere and more strongly at higher altitudes with the strongest reflection at the transition region. The waves are damped in the lower chromosphere dominantly through Joule dissipation, producing heating strong enough to balance the radiative loss for the quiet chromosphere without invoking anomalous processes or turbulences. The heating rates are larger for weaker background magnetic fields below ?500 km with higher-frequency waves subject to heavier damping. There is an upper cutoff frequency, depending on the background magnetic field, above which the waves are completely damped. At the frequencies below which the waves are not strongly damped, the interaction of reflected waves with the upward propagating waves produces power at their double frequencies, which leads to more damping. The wave energy flux transmitted to the corona is one order of magnitude smaller than that of the driving source.

Tu, Jiannan; Song, Paul [Physics Department and Center for Atmospheric Research, University of Massachusetts, Lowell, MA 01854 (United States)

2013-11-01

342

Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties  

SciTech Connect

Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters. A numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger was developed and the effect of various design parameters on overall heat exchanger size was investigated. It was found that highly conductive metals should be avoided in the design of compact JT heat exchangers. For the geometry considered, the optimal conductivity is around 3.5 W/m-K and can range from 0.3-10 W/m-K without a large loss in performance. The model was implemented with an isenthalpic expansion process. Increasing the cold side inlet temperature from 2K to 2.2 K decreased the liquid fraction from 0.856 to 0.839 which corresponds to a 0.12 g/s increase in supercritical helium supply needed to maintain liquid level in the cooling bath. Lastly, it was found that the effectiveness increased when the heat load was below the design value. Therefore, the heat exchanger should be sized on the high end of the required heat load.

Hansen, B.J.; White, M.J.; Klebaner, A.; /Fermilab

2011-06-10

343

Performance of a variable conductance heat pipe heat exchanger  

Microsoft Academic Search

The performance of an air to air heat exchanger in which heat is transferred to a finned evaporator and from a finned condenser via a heat pipe was evaluated. The variable conductance heat pipe is to the condenser fins a heat source and to the evaporator fins a heat sink. The principal advantage of the variable conductance heat pipe heat

P. D. Chancelor

1983-01-01

344

Rotary magnetic heat pump  

DOEpatents

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

Kirol, L.D.

1987-02-11

345

Antigravity heat pipe  

Microsoft Academic Search

The general design and principle of operation of an antigravity heat pipe, in which the heat transfer agent is supplied to the evaporator against the force of gravity, are descussed. Analytical expressions describing the operation of the heat pipe are presented, as are experimental results obtained for an acetone-charged antigravity heat pipe.

N. I. Kliuev

1989-01-01

346

Loop heat pipes  

Microsoft Academic Search

Loop heat pipes (LHPs) are two-phase heat-transfer devices with capillary pumping of a working fluid. They possess all the main advantages of conventional heat pipes, but owing to the original design and special properties of the capillary structure are capable of transferring heat efficiency for distances up to several meters at any orientation in the gravity field, or to several

Yu. F. Maydanik

2005-01-01

347

Solar Heating Equipment  

NASA Technical Reports Server (NTRS)

Solar Unlimited, Inc.'s suncatcher line includes a variety of solar arrays, derived from NASA's satellite program: water heating only, partial home heating, or water and whole house central heating. Solar Unlimited developed a set of vigorous requirements to avoid problems common to solar heating technologies.

1981-01-01

348

Direct fired heat exchanger  

DOEpatents

A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

Reimann, Robert C. (Lafayette, NY); Root, Richard A. (Spokane, WA)

1986-01-01

349

Woven heat exchanger  

DOEpatents

In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Piscitella, Roger R. (Idaho Falls, ID)

1987-01-01

350

Nature's Heat Exchangers.  

ERIC Educational Resources Information Center

Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

Barnes, George

1991-01-01

351

Mass and Heat Recovery  

E-print Network

In the last few years heat recovery was under spot and in air conditioning fields usually we use heat recovery by different types of heat exchangers. The heat exchanging between the exhaust air from the building with the fresh air to the building...

Hindawai, S. M.

2010-01-01

352

Thermoelectric heat exchange element  

DOEpatents

A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

2007-08-14

353

Observations of auroral E-region plasma waves and electron heating with EISCAT and a VHF radar interferometer  

NASA Astrophysics Data System (ADS)

Two radars were used simultaneously to study naturally occurring electron heating events in the auroral E-region ionosphere. During a joint campaign in March 1986 the Cornell University Portable Radar Interferometer (CUPRI) was positioned to look perpendicular to the magnetic field to observe unstable plasma waves over Tromso, Norway, while EISCAT measured the ambient conditions in the unstable region. On two nights EISCAT detected intense but short lived (less than 1 min) electron heating events during which the temperature suddenly increased by a factor of 2-4 at altitudes near 108 km and the electron densities were less than 70,000/cu cm. On the second of these nights CUPRI was operating and detected strong plasma waves with very large phase velocities at precisely the altitudes and times at which the heating was observed. The altitudes, as well as one component of the irregularity drift velocity, were determined by interferometric techniques. From the observations and our analysis, it is concluded that the electron temperature increases were caused by plasma wave heating and not by either Joule heating or particle precipitation.

Providakes, J.; Farley, D. T.; Fejer, B. G.; Sahr, J.; Swartz, W. E.

1988-05-01

354

Heat cascading regenerative sorption heat pump  

NASA Technical Reports Server (NTRS)

A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

Jones, Jack A. (Inventor)

1995-01-01

355

Thermodynamics and Mechanical Equivalent of Heat  

ERIC Educational Resources Information Center

This paper is the first part of a three-part project "How the principle of energy conservation evolved between 1842 and 1870: the view of a participant". This paper aims at showing how the new ideas of Mayer and Joule were received, what constituted the new theory in the period under study, and how it was supported experimentally. A…

Kipnis, Nahum

2014-01-01

356

Extreme degree of ionization in homogenous micro-capillary plasma columns heated by ultrafast current pulses.  

PubMed

Homogeneous plasma columns with ionization levels typical of megaampere discharges are created by rapidly heating gas-filled 520-?m-diameter channels with nanosecond rise time current pulses of 40 kA. Current densities of up to 0.3??GA?cm^{-2} greatly increase Joule heating with respect to conventional capillary discharge Z pinches, reaching unprecedented degrees of ionization for a high-Z plasma column heated by a current pulse of remarkably low amplitude. Dense xenon plasmas are ionized to Xe^{28+}, while xenon impurities in hydrogen discharges reach Xe^{30+}. The unique characteristics of these hot, ?300:1 length-to-diameter aspect ratio plasmas allow the observation of unexpected spectroscopic phenomena. Axial spectra show the unusual dominance of the intercombination line over the resonance line of He-like Al by nearly an order of magnitude, caused by differences in opacities in the axial and radial directions. These plasma columns could enable the development of sub-10-nm x-ray lasers. PMID:25793819

Avaria, G; Grisham, M; Li, J; Tomasel, F G; Shlyaptsev, V N; Busquet, M; Woolston, M; Rocca, J J

2015-03-01

357

STELLAR MAGNETIC FIELDS AS A HEATING SOURCE FOR EXTRASOLAR GIANT PLANETS  

SciTech Connect

It has been observed that hot Jupiters located within 0.08 AU of their host stars commonly display radii in excess of those expected based on models. A number of theoretical explanations for this phenomenon have been suggested, but the ability of any one mechanism to account for the full range of observations remains to be rigorously proven. I identify an additional heating mechanism, arising from the interaction of the interplanetary magnetic field and the planetary magnetosphere, and show that this is capable of providing enough energy to explain the observed planetary radii. Such a model predicts that the degree of heating should be dependent on the stellar magnetic field, for which stellar activity serves as a proxy. Accordingly, I examine populations of hot Jupiters from the Kepler database and confirm that stellar activity (determined using Kepler CDPP levels) is correlated with the presence of planetary radii inflated beyond the basal level of R = 0.87 R{sub J} identified by previous researchers. I propose that the primary mechanism for transferring energy from the magnetosphere to the planetary interior is Joule heating arising from global electric circuits analogous to those seen in solar system objects.

Buzasi, D., E-mail: dbuzasi@fgcu.edu [College of Arts and Sciences, Florida Gulf Coast University, Fort Myers, FL 33965 (United States)

2013-03-10

358

Characteristics of the heat resistant FBG sensor under laser cladding condition  

NASA Astrophysics Data System (ADS)

We have developed heat resistant strain sensors using laser processing techniques. The application is aimed at structural health monitoring for high temperature piping systems. This situation requires extraordinary durability such as radiation resistance and noise isolation due to adverse conditions caused by nuclear reactions or electro-magnetic pulses. We proposed that a Fiber Bragg Grating (FBG) sensor made by femtosecond laser processing could be the best candidate. The combination of fabric reinforcement and a heatproof adhesive mold successfully protected the fragile optical fiber once the fiber was installed on the piping material's surface. To make the best use of the heat-resistant characteristic, we fixed the FBG sensor by metal mold. A groove was processed onto the surface of a SUS metal plate with a grindstone. We used a Quasi-CW laser to weld a filler wire onto the plate. The optical fiber was situated under the filler wire before was heated by laser pulses with 10 joule energy and a duration of 10 ms. A series of weld pool formed a sealing clad on the groove. The FBG sensor was buried at a depth of 1 mm over a length of 1 cm. No degradation in its reflection spectra was detected before and after the processing. The FBG sensor can detect the vibration of the plate caused by impact shocks. In this paper, the Bragg peak shift of the FBG sensor under laser cladding condition has been discussed.

Nishimura, A.; Terada, T.

2014-02-01

359

Conditions for Aeronomic Applicability of the Classical Electron Heat Conduction Formula  

NASA Technical Reports Server (NTRS)

Conditions for the applicability of the classical formula for heat conduction in the electrons in ionized gas are investigated. In a fully ionised gas ( V(sub en) much greater than V(sub ei)), when the mean free path for electron-electron (or electron-ion) collisions is much larger than the characteristic thermal scale length of the observed system, the conditions for applicability break down. In the case of the Venus ionosphere this breakdown is indicated for a large fraction of the electron temperature data from altitudes greater than 180 km, for electron densities less than 10(exp 4)/cc cm. In a partially ionised gas such that V(sub en) much greater than V(sub ei) there is breakdown of the formula not only when the mean free path of electrons greatly exceeds the thermal scale length, but also when the gradient of neutral particle density exceeds the electron thermal gradient. It is shown that electron heat conduction may be neglected in estimating the temperature of joule heated electrons by observed strong 100 Hz electric fields when the conduction flux is limited by the saturation flux. The results of this paper support our earlier aeronomical arguments against the hypothesis of planetary scale whistlers for the 100 Hz electric field signal. In turn this means that data from the 100 Hz signal may not be used to support the case for lightning on Venus.

Cole, K. D.; Hoegy, W. R.

1998-01-01

360

Mode-selected heat flow through a one-dimensional waveguide network  

NASA Astrophysics Data System (ADS)

Cross-correlated measurements of thermal noise are performed to determine the electron temperature in nanopatterned channels of a GaAs/AlGaAs heterostructure at 4.2 K. Two-dimensional (2D) electron reservoirs are connected via an extended one-dimensional (1D) electron waveguide network. Hot electrons are produced using a current Ih in a source 2D reservoir, are transmitted through the ballistic 1D waveguide, and relax in a drain 2D reservoir. We find that the electron temperature increase, ?Te, in the drain is proportional to the square of the heating current Ih, as expected from Joule's law. No temperature increase is observed in the drain when the 1D waveguide does not transmit electrons. Therefore, we conclude that electron-phonon interaction is negligible for heat transport between 2D reservoirs at temperatures below 4.2 K. Furthermore, mode control of the 1D electron waveguide by application of a top-gate voltage reveals that ?Te is not proportional to the number of populated subbands N, as previously observed in single 1D conductors. This can be explained with the splitting of the heat flow in the 1D waveguide network.

Riha, Christian; Miechowski, Philipp; Buchholz, Sven S.; Chiatti, Olivio; Wieck, Andreas D.; Reuter, Dirk; Fischer, Saskia F.

2015-02-01

361

Extreme Degree of Ionization in Homogenous Micro-Capillary Plasma Columns Heated by Ultrafast Current Pulses  

NASA Astrophysics Data System (ADS)

Homogeneous plasma columns with ionization levels typical of megaampere discharges are created by rapidly heating gas-filled 520 -? m -diameter channels with nanosecond rise time current pulses of 40 kA. Current densities of up to 0.3 GA cm-2 greatly increase Joule heating with respect to conventional capillary discharge Z pinches, reaching unprecedented degrees of ionization for a high-Z plasma column heated by a current pulse of remarkably low amplitude. Dense xenon plasmas are ionized to Xe28 + , while xenon impurities in hydrogen discharges reach Xe30 + . The unique characteristics of these hot, ˜300 :1 length-to-diameter aspect ratio plasmas allow the observation of unexpected spectroscopic phenomena. Axial spectra show the unusual dominance of the intercombination line over the resonance line of He-like Al by nearly an order of magnitude, caused by differences in opacities in the axial and radial directions. These plasma columns could enable the development of sub-10-nm x-ray lasers.

Avaria, G.; Grisham, M.; Li, J.; Tomasel, F. G.; Shlyaptsev, V. N.; Busquet, M.; Woolston, M.; Rocca, J. J.

2015-03-01

362

Heat Pipe Technology  

NASA Technical Reports Server (NTRS)

The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

1981-01-01

363

Enhancement of heat transfer  

NASA Astrophysics Data System (ADS)

Recent publications on enhancement of heat transfer are reviewed, emphasizing the effects of roughness elements, fins, and porous surfaces. Enhancement of forced convective heat transfer on roughened surfaces, performance evaluation of enhanced surfaces, viscous flows in cooled tubes and tubes with swirlers, and active methods of enhancement are addressed. Aspects of pool boiling heat transfer are considered, including nucleate boiling heat transfer on rough surfaces and porous surfaces, and maximum and minimum heat fluxes. Evaporative heat transfer is discussed for thin-film evaporation on structured surfaces and liquid spray cooling of a heated surface. Condensation heat transfer on external surfaces is covered, including filmwise condensation on vertical finned and fluted surfaces and on horizontal tubes. In-tube boiling and condensation are treated, discussing their enhancement by fins and inserts, as well as critical heat flux in coiled, rifled, and corrugated tubes.

Nakayama, W.

364

Heat transfer -- Portland 1995  

SciTech Connect

This Volume contains a total of forty seven papers, plus two abstracts, divided among eleven technical sessions on the following topics: Multiphase flow in waste management and environmental restoration, Parts 1 and 2; forced convection interphase transfer with particles; thermal-hydraulics in nuclear reactor systems, heat transfer phenomena in non-commercial reactors; heat transfer in containment; erosion, corrosion, and process heat transfer in power plant systems; innovative applications of solar energy; heat transfer aspects of space power and propulsion; fundamentals of heat pipes in space applications; and heat transfer and energy conversion in dual use power systems. Papers have been abstracted separately for inclusion on the data base.

El-Genk, M.S. [ed.] [Univ. of New Mexico, Albuquerque, NM (United States)

1995-12-31

365

Flexible Heating Head  

NASA Technical Reports Server (NTRS)

United States Air Force is investigating method of repairing aircraft by use of adhesive bonding with induction heating to cure adhesive. Fast-acting and reliable induction heating device that is lightweight, portable, and easy to use needed for such applications. Newly developed flexible heating head lightweight and conforms to complex, curved surfaces. Incorporates principles and circuitry of toroid joining gun described in "Toroid Joining Gun for Fittings and Couplings" (LAR-14278). Concentrates heat in local area through induction heating. Flexible heating head contains tank circuit, connected via cable to source of power.

Fox, Robert L.; Johnson, Samuel D.; Coultrip, Robert H.; Phillips, W. Morris

1994-01-01

366

Heat transfer system  

DOEpatents

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.

Not Available

1980-03-07

367

Heat transfer system  

DOEpatents

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.

McGuire, Joseph C. (Richland, WA)

1982-01-01

368

Wound tube heat exchanger  

DOEpatents

What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.

Ecker, Amir L. (Duncanville, TX)

1983-01-01

369

Microscale Regenerative Heat Exchanger  

NASA Technical Reports Server (NTRS)

The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

2006-01-01

370

Summer HeatSummer Heat Heat stress solutions  

E-print Network

is older, over weight, in poor physical condition, taking allergy medication, or not used to being out to the heat. Become a weather watcher. Set up a small weather station (with a high/low thermom eter, rain

Liskiewicz, Maciej

371

Heat Wave Safety Checklist  

MedlinePLUS

... heat has caused more deaths than all other weather events, including floods. A heat wave is a ... stroke include hot, red skin which may be dry or moist; changes in consciousness; vomiting; and high ...

372

Monogroove liquid heat exchanger  

NASA Technical Reports Server (NTRS)

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).

Brown, Richard F. (Inventor); Edelstein, Fred (Inventor)

1990-01-01

373

HEAT TRANSFER FLUIDS  

E-print Network

The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...

Lenert, Andrej

2012-01-01

374

Radial heat flux transformer  

NASA Technical Reports Server (NTRS)

Unit moves heat radially from small diameter shell to larger diameter shell, or vice versa, with negligible temperature drop, making device useful wherever heating or cooling of concentrically arranged materials, substances, and structures is desired.

Basiulis, A.; Buzzard, R. J.

1971-01-01

375

Metal-insulator transition upon heating and negative-differential-resistive-switching induced by self-heating in BaCo{sub 0.9}Ni{sub 0.1}S{sub 1.8}  

SciTech Connect

The layered compound BaCo{sub 1?x}Ni{sub x}S{sub 2?y} (0.05?heating in polycrystalline BaCo{sub 1?x}Ni{sub x}S{sub 2?y} (nominal x?=?0.1 and y?=?0.2). These were due to the steep metal to insulator transition upon heating followed by the activated behavior of the resistivity above the transition. The major role of Joule heating in switching is supported by the absence of nonlinearity in the current as function of voltage, I(V), obtained in pulsed measurements, in the range of electric fields relevant to d.c. measurements. The voltage-controlled negative differential resistance around the threshold for switching was explained by a simple model of self-heating. The main difficulty in modeling I(V) from the samples resistance as function of temperature R(T) was the progressive increase of R(T), and to a lesser extend the decrease of the resistance jumps at the transitions, caused by the damage induced by cycling through the transitions by heating or self-heating. This was dealt with by following systematically R(T) over many cycles and by using the data of R(T) in the heating cycle closest to that of the self-heating one.

Fisher, B.; Genossar, J.; Chashka, K. B.; Patlagan, L.; Reisner, G. M. [Physics Department, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

2014-04-14

376

Metal-insulator transition upon heating and negative-differential-resistive-switching induced by self-heating in BaCo0.9Ni0.1S1.8  

NASA Astrophysics Data System (ADS)

The layered compound BaCo1-xNixS2-y (0.05 < x < 0.2 and 0.05 < y < 0.2) exhibits an unusual first-order structural and electronic phase transition from a low-T monoclinic paramagnetic metal to a high-T tetragonal antiferromagnetic insulator around 200 K with huge hysteresis (˜40 K) and large volume change (˜0.01). Here, we report on unusual voltage-controlled resistive switching followed by current-controlled resistive switching induced by self-heating in polycrystalline BaCo1-xNixS2-y (nominal x = 0.1 and y = 0.2). These were due to the steep metal to insulator transition upon heating followed by the activated behavior of the resistivity above the transition. The major role of Joule heating in switching is supported by the absence of nonlinearity in the current as function of voltage, I(V), obtained in pulsed measurements, in the range of electric fields relevant to d.c. measurements. The voltage-controlled negative differential resistance around the threshold for switching was explained by a simple model of self-heating. The main difficulty in modeling I(V) from the samples resistance as function of temperature R(T) was the progressive increase of R(T), and to a lesser extend the decrease of the resistance jumps at the transitions, caused by the damage induced by cycling through the transitions by heating or self-heating. This was dealt with by following systematically R(T) over many cycles and by using the data of R(T) in the heating cycle closest to that of the self-heating one.

Fisher, B.; Genossar, J.; Chashka, K. B.; Patlagan, L.; Reisner, G. M.

2014-04-01

377

Unsteady heat transfer in heat pipes  

NASA Astrophysics Data System (ADS)

The purpose was to investigate the unsteady heat transfer associated with a heat pipe during start up operation. Initial studies were conducted with a variety of heat pipe screen wick configurations in order to develop a mathematical expression for the flow velocity of a fluid inducted by the capillary structure of the wick. This mathematical model was solved first numerically and then simplified to provide a closed form solution. The results were compared with the experimental data and proved to provide consistent results with plus or minus 10%. A lumped parameter model of the heat pipe was next developed so that the transient operation of the heat pipe could be predicted. Upon evalaution of the model it was shown that the model and the experimental data agreed quite well in overall performance but an initial period of performance was identified where the experimental results differed significantly from the lumped parameter model. During this initial period of operation, large temperature gradients were observed, and it was theorized that the effect was a result of the interdependence of the hydrodynamics and the heat transfer characteristics of the heat pipe.

Beam, J. E.

378

Methods of Heat Transfer  

NSDL National Science Digital Library

To help students better understand conduction, convection, and radiation as methods of heat transfer in solids, liquids and gases. Let's look at all three methods of heat transfer ... Overview of Conduction, Convection, Radiation Conduction- 1. Explain what happens as heat energy is supplied to one part of a solid. 2. Explain how energy is transferred by conduction through a solid. Convection- 1. What is ?anything fluid? ? Include two examples. 2. Describe how and why heat is transferred in ...

Mrs. Carlone

2006-11-12

379

Urban Heat Islands  

NSDL National Science Digital Library

In this activity, students learn about the urban heat island effect by investigating which areas of their schoolyard have higher temperatures - trees, grass, asphalt, and other materials. Based on their results, they hypothesize how concentrations of surfaces that absorb heat might affect the temperature in cities - the urban heat island effect. Then they analyze data about the history of Los Angeles heat waves and look for patterns in the Los Angeles climate data and explore patterns.

Lisa Gardiner

380

Isolated Quantum Heat Engine  

NASA Astrophysics Data System (ADS)

We present a theoretical and numerical analysis of a quantum system that is capable of functioning as a heat engine. This system could be realized experimentally using cold bosonic atoms confined to a double well potential that is created by splitting a harmonic trap with a focused laser. The system shows thermalization, and can model a reversible heat engine cycle. This is the first demonstration of the operation of a heat engine with a finite quantum heat bath.

Fialko, O.; Hallwood, D. W.

2012-02-01

381

Solar heat receiver  

DOEpatents

A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

Hunt, Arlon J. (Oakland, CA); Hansen, Leif J. (Berkeley, CA); Evans, David B. (Orinda, CA)

1985-01-01

382

Abrasion resistant heat pipe  

DOEpatents

A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

Ernst, Donald M. (Leola, PA)

1984-10-23

383

Heat Transfer Guest Editorial  

E-print Network

Journal of Heat Transfer Guest Editorial We are indeed delighted in bringing out this special issue was showcased in diverse areas such as traditional heat and mass transfer, lab-on-chip, sensors, biomedical applica- tions, micromixers, fuel cells, and microdevices. Selected papers in the field of heat transfer

Kandlikar, Satish

384

Champagne Heat Pump  

NASA Technical Reports Server (NTRS)

The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

Jones, Jack A.

2004-01-01

385

Heat Recovery System  

NASA Technical Reports Server (NTRS)

Ball Metal's design of ducting and controls for series of roof top heat exchangers was inspired by Tech Briefs. Heat exchangers are installed on eight press and coating lines used to decorate sheet metal. The heat recovery system provides an estimated energy savings of more than $250,000 per year.

1984-01-01

386

Liquid heat capacity lasers  

DOEpatents

The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

Comaskey, Brian J. (Walnut Creek, CA); Scheibner, Karl F. (Tracy, CA); Ault, Earl R. (Livermore, CA)

2007-05-01

387

The heat pipe  

Microsoft Academic Search

The heat pipe is a device having a high thermal conductance which utilizes the transport of a vapour and rejection of latent heat to achieve efficient thermal energy transport. The theory of heat pipes is well developed. Their use in applications involving temperatures in the cryogenic regime, and with development units running as high as 2000 degrees C, shows that

P. D. Dunn; D. A. Reay

1973-01-01

388

Waste heat recovery system  

Microsoft Academic Search

This invention relates to a system for reclaiming or recovering heat which would otherwise be lost from a heating plant. The invention accordingly relates to a heating plant incorporating a plurality of boilers, including a stand-by boiler, there being means for supplying fuel and air to at least one of said boilers, except for the stand-by boiler, and flue gas

Beckett

1983-01-01

389

Waste heat recovery boiler  

Microsoft Academic Search

A waste heat recovery boiler is described which utilizes an exhaust gas of a gas turbine and generates steam for driving a steam turbine. The improvement wherein at least two denitrating devices for removing NO\\/sub x\\/ components in the exhaust gas therefrom are disposed inside the waste heat recovery boiler. The waste heat recovery boiler is equipped with fuel economizers

E. Yanai; T. Kuribayashi

1987-01-01

390

Waste heat recovery boiler  

Microsoft Academic Search

A waste heat recovery boiler for generating steam by utilizing a flue gas discharged from a gas turbine as a heat source comprises an economizer for preheating feedwater by the flue gas, an evaporator for evaporating the preheated feedwater, and a superheater for generating a steam for driving a steam prime mover by heating the evaporated feedwater. The economizer, the

H. Taiji Inui; M. Makoto Sasaki

1984-01-01

391

Waste heat recovery system  

Microsoft Academic Search

This patent describes a waste heat recovery system. It comprises a conduit for conveying an exhaust gas stream; a boiler assembly connected to the conduit including a heat recovery steam generator through which the exhaust gas if flowed, and characterized by a high temperature stream tube heat exchanger and, at a downstream location relative thereto, a water-tube boiler; an ammonia

E. M. Smith; R. C. Cornelison

1989-01-01

392

Fireplace heat generating system  

Microsoft Academic Search

A fireplace heat generating system includes a plurality of conduits which cooperate to define a grate for seating logs or other combustible material there atop. The conduits are in communication with a heat deflector or shield at the base thereof. Discharge or heat issuing conduits or other suitable conveyances are disposed at the top of the shield and are in

Emmendorfer

1981-01-01

393

Geothermal heat recovery system  

Microsoft Academic Search

A system for recovering heat from a geothermal well includes a quantity of heavy drilling mud filling the bottom of the geothermal well. A hollow heat absorber is disposed within the drilling mud in the well bottom. The heat absorber is supplied with a working fluid such as freon through a supply pipe extending from the top of the well,

W. F. Ash; F. R. Ash

1978-01-01

394

Waste heat recovery system  

Microsoft Academic Search

A system for recovering the waste heat normally exhausted into the atmosphere by chemical or other processing plants is described. The system comprises a substantially self-contained apparatus for receiving hot exhaust gases and extracting the waste heat for some beneficial use, such as pre-heating inlet air in an inlet plenum. The system may include temperature and pressure controls which enhance

J. J. Jr. Fallon; J. B. Blair; D. R. Phelps

1978-01-01

395

Electricity from waste heat  

Microsoft Academic Search

In industry and in ships, large amounts of waste heat with quite a high release temperature are produced: examples are combustion gases and the exhaust gases of ceramic kilns. Very often they cannot be used for heating purposes because of long transport distances or because there is no local district heating network. Thus, a practical solution would be to convert

Jaakko Larjola; Olli Lindgren; Esa Vakkilainen

1991-01-01

396

Heat exchangers for low grade waste heat  

SciTech Connect

The paper describes a user friendly computer program written for the design and optimization of roll bond aluminum heat exchangers and its validation against experimental test data. Test results for two different designs of heat exchanger panel, one serpentine and one dimple, are also given. The dimple design is shown to be superior to the serpentine one giving a 75% increase in heat transfer for a modest increase in pressure drop. Finally, a comparison of the economics of equivalent aluminum, stainless steel and titanium units for sea-water applications is presented.

Hay, E. [Nisymco Inc., Montreal, Quebec (Canada); Al-Witry, A.; Aroussi, A.; Hay, N. [Univ. of Nottingham (United Kingdom)

1996-12-31

397

Semicollisional heat flux in laser heated plasmas  

NASA Astrophysics Data System (ADS)

The semicollisional transport theory in laser heated plasmas is presented. The Fokker-Planck equation that includes the electron-electron interaction up to the first anisotropy is solved numerically for arbitrary collisionality range. The inverse bremsstrahlung absorption of the laser energy by the electrons is taken into account. Nonlocal heat flux formulas due to the thermal gradients and to the laser heating, which are in good agreement with the numerical results, are proposed. These transport coefficients are compared with the results of the literature.

Tahraoui, A.; Bendib, A.

2002-07-01

398

A corrosive resistant heat exchanger  

DOEpatents

A corrosive and erosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is pumped through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium. 3 figs., 3 tabs.

Richlen, S.L.

1987-08-10

399

Chemical heat pump  

DOEpatents

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer. The heat pump part of the system heats or cools a house or other structure through a combination of evaporation and absorption or, conversely, condensation and desorption, in a pair of containers. A set of automatic controls change the system for operation during winter and summer months and for daytime and nighttime operation to satisfactorily heat and cool a house during an entire year. The absorber chamber is subjected to solar heating during regeneration cycles and is covered by one or more layers of glass or other transparent material. Daytime home air used for heating the home is passed at appropriate flow rates between the absorber container and the first transparent cover layer in heat transfer relationship in a manner that greatly reduce eddies and resultant heat loss from the absorbant surface to ambient atmosphere.

Greiner, Leonard (2750-C Segerstrom Ave., Santa Ana, CA 92704)

1980-01-01

400

"E" Heating Head  

NASA Technical Reports Server (NTRS)

Two separate areas heated inductively for adhesive bonding in single operation. "E" heating head developed to satisfy need for fast-acting and reliable induction heating device. Used in attaching "high-hat" stiffeners to aircraft panels. Incorporates principles and circuitry of toroid joining gun. Width and length configured to provide variously sized heat zones, depending on bonding requirements. Lightweight, portable and provides rapid, reliable heating of dual areas in any environment. Well suited for flight-line and depot maintenance, and battlefield repair. Also useful in automotive assembly lines to strengthen automobile panels.

Fox, Robert L.; Swaim, Robert J.; Johnson, Samuel D.; Coultrip, Robert H.; Phillips, W. Morris; Copeland, Carl E.

1994-01-01

401

Absorption heat pump system  

DOEpatents

An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

Grossman, Gershon (Oak Ridge, TN); Perez-Blanco, Horacio (Knoxville, TN)

1984-01-01

402

Heat pipe investigations  

NASA Technical Reports Server (NTRS)

The OAO-C spacecraft has three circular heat pipes, each of a different internal design, located in the space between the spacecraft structural tube and the experiment tube, which are designed to isothermalize the structure. Two of the pipes are used to transport high heat loads, and the third is for low heat loads. The test problems deal with the charging of the pipes, modifications, the mobile tilt table, the position indicator, and the heat input mechanisms. The final results showed that the techniques used were adequate for thermal-vacuum testing of heat pipes.

Marshburn, J. P.

1972-01-01

403

Heating and cooling  

NSDL National Science Digital Library

Heating and cooling homes and businesses require a major energy commitment. This informational piece, part of a series about the future of energy, introduces students to the energy needed to heat and cool homes and workplaces. Students explore energy requirements in the home and at work and discuss current technologies to improve heating and cooling efficiencies. Articles on heat pumps and solar heating and cooling techniques are accessible from a sidebar. A link to a PBS NewsHour article on air conditioning efficiency and a link to material discussing alternatives to air conditioning are also provided. Copyright 2005 Eisenhower National Clearinghouse

Iowa Public Television. Explore More Project

2004-01-01

404

Flexible heating head for induction heating  

NASA Technical Reports Server (NTRS)

An induction heating head includes a length of wire having first and second opposite ends and being wound in a flat spiral shape to form an induction coil, a capacitor connected to the first and second ends of the wire, the induction coil and capacitor defining a tank circuit, and a flexible, elastomeric body molded to encase the induction coil. When a susceptor is placed in juxtaposition to the body, and the tank circuit is powered, the susceptor is inductively heated.

Fox, Robert L. (inventor); Johnson, Samuel D. (inventor); Coultrip, Robert H. (inventor); Phillips, W. Morris (inventor)

1993-01-01

405

Stirling engine heat-actuated heat pump  

Microsoft Academic Search

A Stirling-engine-driven heat-actuated heat pump (HAHP) system developed at Mechanical Technology Incorporated (MTI) consists of a free-piston Stirling engine (FPSE) driver, a diaphragm-actuated hydraulic coupling, and a Rankine-cycle, resonant-linear refrigerant compressor. This system has been under development at MTI for the past two years; within the last six months, the unit has been placed on test. This paper describes the

R. A. Ackerman; J. English; T. Moynihan

1983-01-01

406

Stirling engine heat-actuated heat pump  

SciTech Connect

A Stirling-engine-driven heat-actuated heat pump (HAHP) system developed at Mechanical Technology Incorporated (MTI) consists of a free-piston Stirling engine (FPSE) driver, a diaphragm-actuated hydraulic coupling, and a Rankine-cycle, resonant-linear refrigerant compressor. This system has been under development at MTI for the past two years; within the last six months, the unit has been placed on test. This paper describes the system and test results achieved to date.

Ackerman, R.A.; English, J.; Moynihan, T.

1983-08-01

407

Heat pump apparatus  

DOEpatents

A heat pump apparatus including a compact arrangement of individual tubular reactors containing hydride-dehydride beds in opposite end sections, each pair of beds in each reactor being operable by sequential and coordinated treatment with a plurality of heat transfer fluids in a plurality of processing stages, and first and second valves located adjacent the reactor end sections with rotatable members having multiple ports and associated portions for separating the hydride beds at each of the end sections into groups and for simultaneously directing a plurality of heat transfer fluids to the different groups. As heat is being generated by a group of beds, others are being regenerated so that heat is continuously available for space heating. As each of the processing stages is completed for a hydride bed or group of beds, each valve member is rotated causing the heat transfer fluid for the heat processing stage to be directed to that bed or group of beds. Each of the end sections are arranged to form a closed perimeter and the valve member may be rotated repeatedly about the perimeter to provide a continuous operation. Both valves are driven by a common motor to provide a coordinated treatment of beds in the same reactors. The heat pump apparatus is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators but may be used with any source of heat, including a source of low-grade heat.

Nelson, Paul A. (Wheaton, IL); Horowitz, Jeffrey S. (Woodridge, IL)

1983-01-01

408

Deployable Heat Pipe Radiator  

NASA Technical Reports Server (NTRS)

A 1.2- by 1.8-m variable conductance heat pipe radiator was designed, built, and tested. The radiator has deployment capability and can passively control Freon-21 fluid loop temperatures under varying loads and environments. It consists of six grooved variable conductance heat pipes attached to a 0.032-in. aluminum panel. Heat is supplied to the radiator via a fluid header or a single-fluid flexible heat pipe header. The heat pipe header is an artery design that has a flexible section capable of bending up to 90 degrees. Radiator loads as high as 850 watts were successfully tested. Over a load variation of 200 watts, the outlet temperature of the Freon-21 fluid varied by 7 F. An alternate control system was also investigated which used a variable conductance heat pipe header attached to the heat pipe radiator panel.

Edelstein, F.

1975-01-01

409

Nanofluid heat capacities  

NASA Astrophysics Data System (ADS)

Significant increases in the heat capacity of heat transfer fluids are needed not only to reduce the costs of liquid heating and cooling processes, but also to bring clean energy producing technologies like concentrating solar power (CSP) to price parity with conventional energy generation. It has been postulated that nanofluids could have higher heat capacities than conventional fluids. In this work, nano- and micron-sized particles were added to five base fluids (poly-? olefin, mineral oil, ethylene glycol, a mixture of water and ethylene glycol, and calcium nitrate tetrahydrate), and the resulting heat capacities were measured and compared with those of the neat base fluids and the weighted average of the heat capacities of the components. The particles used were inert metals and metal oxides that did not undergo any phase transitions over the temperature range studied. In the nanofluids studied here, we found no increase in heat capacity upon the addition of the particles larger than the experimental error.

Starace, Anne K.; Gomez, Judith C.; Wang, Jun; Pradhan, Sulolit; Glatzmaier, Greg C.

2011-12-01

410

Active microchannel heat exchanger  

DOEpatents

The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

Tonkovich, Anna Lee Y. (Pasco, WA) [Pasco, WA; Roberts, Gary L. (West Richland, WA) [West Richland, WA; Call, Charles J. (Pasco, WA) [Pasco, WA; Wegeng, Robert S. (Richland, WA) [Richland, WA; Wang, Yong (Richland, WA) [Richland, WA

2001-01-01

411

Ceramic heat recuperators for industrial heat recovery  

SciTech Connect

Results are presented from a continuing program whose purpose is to demonstrate the technical and economic feasibility of using ceramic heat recuperators for industrial heat recovery. The information presented can be used by engineers in industry to evaluate their specific furnace applications and to estimate the technical requirements and economic benefits from the use of ceramic heat recuperators. Chapter 2 presents methods that can be used to estimate the amount of energy savings by recuperation. Chapter 3 gives a brief background in heat exchanger design theory so that the reader can understand the procedures involved in designing and sizing heat exchangers for a given application. The specific GTE core design and the recuperator fabrication, housing and installation are discussed in Chapter 4. The demonstration project results are presented in Chapter 5. Each demonstration is described and the results, economics and problem areas discussed. The Appendices provide details that will allow the engineer in industry to select a core, size a heat exchanger, calculate the performance, determine energy saved and estimate the economics of using a ceramic recuperator for a specific industrial application. (LCL)

Not Available

1980-05-01

412

Absorption heat pumps  

NASA Astrophysics Data System (ADS)

The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

Huhtinen, M.; Heikkilae, M.; Andersson, R.

1987-03-01

413

Application of heat flux transducers to determine perioperative heat exchange  

Microsoft Academic Search

Perioperative hypothermia is a common problem in anaesthesia. To maintain a constant body heat content it is necessary to achieve a steady state of metabolic heat production and external heat exchange. During anaesthesia and surgery this balance is disturbed. The heat production is decreased to a level below resting metabolic heat production while heat losses increase due to the surgical

T. Perl; A. Bräuer; W. Weyland; U. Braun

2004-01-01

414

Heat pump system  

DOEpatents

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.

Swenson, Paul F.; Moore, Paul B.

1983-06-21

415

Heat pump system  

DOEpatents

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.

Swenson, Paul F. (Shaker Heights, OH); Moore, Paul B. (Fedhaven, FL)

1983-01-01

416

Lunar base heat pump  

NASA Technical Reports Server (NTRS)

A heat pump is a device which elevates the temperature of a heat flow by a means of an energy input. By doing this, the heat pump can cause heat to transfer faster from a warm region to a cool region, or it can cause heat to flow from a cool region to a warmer region. The second case is the one which finds vast commercial applications such as air conditioning, heating, and refrigeration. Aerospace applications of heat pumps include both cases. The NASA Johnson Space Center is currently developing a Life Support Systems Integration Facility (LSSIF, previously SIRF) to provide system-level integration, operational test experience, and performance data that will enable NASA to develop flight-certified hardware for future planetary missions. A high lift heat pump is a significant part of the TCS hardware development associated with the LSSIF. The high lift heat pump program discussed here is being performed in three phases. In Phase 1, the objective is to develop heat pump concepts for a lunar base, a lunar lander, and for a ground development unit for the SIRF. In Phase 2, the design of the SIRF ground test unit is being performed, including identification and evaluation of safety and reliability issues. In Phase 3, the SIRF unit will be manufactured, tested, and delivered to the NASA Johnson Space Center.

Goldman, Jeffrey H.; Tetreault, R.; Fischbach, D.; Walker, D.

1994-01-01

417

Silicon Heat Pipe Array  

NASA Technical Reports Server (NTRS)

Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better suited for the cooling of semiconductor devices.

Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

2013-01-01

418

"Bottle-Brush" Heat Exchanger  

NASA Technical Reports Server (NTRS)

Heat exchanger consists of a metal tube with wires extending inward from wall. Conduction of heat along wires improves heat transfer to gas or other filling. Fluid is heated throughout the cross section of tube. Suggested applications are refrigerators, heat engines, thermal instrumentation, and heat switches.

Tward, E.; Gatewood, J. R.

1982-01-01

419

Numerical and experimental calibration of calorimetric sample cell dedicated to nuclear heating measurements  

SciTech Connect

Online nuclear measurements inside experimental channels of MTRs are needed for experimental works (to design set-ups) and for numerical works (input data) in order to better understanding complex phenomena occurring during the accelerated ageing of materials and the irradiation of nuclear fuel. In this paper we focus only on one kind of measurements: nuclear heating performed by means of a radiometric calorimeter. The aims of numerical and experimental works are firstly to optimize the sensor response for new energy deposit ranges and then to miniaturize this sensor for JHR irradiation conditions A first calorimeter, developed previously by the CEA, is studied. It corresponds to a graphite differential calorimeter divided into two twin cells (a reference cell, and a sample one). It is used with a non adiabatic mode or heat flow mode. Experimental calibration of the sample cell is presented. In that case, energy deposit is simulated by Joule effect and the sample cell is inserted into a bath at a regulated temperature and controlled flow. The response of the sensor is shown versus electrical power imposed for two flow regimes (intensive or moderated forced convection). These experimental results are compared to numerical works and improvements are discussed. (authors)

Brun, J.; Reynard, C.; Merroun, O. [Chemistry Laboratory of Provence LCP UMR 6264 - Universite de Provence, Centre St. Jerome, Bat. Madirel, 13397 Marseille Cedex 20 (France); Lyoussi, A. [French Alternatives Energies and Atomic Energy Commission CEA, Direction de l'Energie Nucleaire DEN, Centre de Cadarache, 13108 Saint-Paul-Lez-Durance (France); Carette, M.; Janulyte, A.; Zerega, Y.; Andre, J. [Chemistry Laboratory of Provence LCP UMR 6264 - Universite de Provence, Centre St. Jerome, Bat. Madirel, 13397 Marseille Cedex 20 (France); Bignan, G.; Chauvin, J. P.; Fourmentel, D.; Gonnier, C.; Guimbal, P.; Malo, J. Y.; Villard, J. F. [French Alternatives Energies and Atomic Energy Commission CEA, Direction de l'Energie Nucleaire DEN, Centre de Cadarache, 13108 Saint-Paul-Lez-Durance (France)

2011-07-01

420

On the Concept of Energy: Eclecticism and Rationality  

ERIC Educational Resources Information Center

In the theory of heat of the first half of the nineteenth century, heat was a substance. Mayer and Joule contradicted this thesis but developed different concepts of heat. Heat was a force for Mayer and a motion for Joule. Both Mayer and Joule determined the mechanical equivalent of heat. This result was, however, justified in accordance with…

Coelho, Ricardo Lopes

2014-01-01

421

Analyses of Thermal Conduction and Stress Induced by Electric Current in an Infinite Thin Plate with an Elliptical Hole  

Microsoft Academic Search

Uniform electric current at infinity is applied to a thin infinite conductor with an elliptical hole disturbing the electric current, which gives rise to Joule heat, temperature increase and heat flux. Joule heat produces uniform and uneven temperature fields which in turn initiate thermal stress. These electrical current, Joule heat, temperature, heat flux and thermal stress analyses are carried out

Norio Hasebe; Christian Bucher; Rudolf Heuer

2009-01-01

422

Heat transfer from oriented heat exchange areas  

NASA Astrophysics Data System (ADS)

This paper deals with the transfer of heat-driven heat transfer surface area in relation to the construction of the criterion equation for "n" horizontal pipe one about another. On the bases of theoretical models have been developed for calculating the thermal performance of natural convection by Churilla and Morgan, for various pipe diameters and temperatures. These models were compared with models created in CFD-Fluent Ansys the same boundary conditions. The aim of the analyse of heat and fluxional pipe fields "n" pipes one about another at natural convection is the creation of criterion equation on the basis of which the heat output of heat transfer from pipe oriented areas one above another with given spacing could be quantified. At presence a sum of criterion equations exists for simple geometrical shapes of individual oriented geometrical areas but the criterion equation which would consider interaction of fluxional field generated by free convection from multiple oriented areas is not mentioned in standardly accessible technical literature and other magazine publications.

Vantuch, Martin; Huzvar, Jozef; Kapjor, Andrej

2014-03-01

423

Heat-pipe Earth.  

PubMed

The heat transport and lithospheric dynamics of early Earth are currently explained by plate tectonic and vertical tectonic models, but these do not offer a global synthesis consistent with the geologic record. Here we use numerical simulations and comparison with the geologic record to explore a heat-pipe model in which volcanism dominates surface heat transport. These simulations indicate that a cold and thick lithosphere developed as a result of frequent volcanic eruptions that advected surface materials downwards. Declining heat sources over time led to an abrupt transition to plate tectonics. Consistent with model predictions, the geologic record shows rapid volcanic resurfacing, contractional deformation, a low geothermal gradient across the bulk of the lithosphere and a rapid decrease in heat-pipe volcanism after initiation of plate tectonics. The heat-pipe Earth model therefore offers a coherent geodynamic framework in which to explore the evolution of our planet before the onset of plate tectonics. PMID:24067709

Moore, William B; Webb, A Alexander G

2013-09-26

424

Heat pipe development  

NASA Technical Reports Server (NTRS)

The objective of this program was to investigate analytically and experimentally the performance of heat pipes with composite wicks--specifically, those having pedestal arteries and screwthread circumferential grooves. An analytical model was developed to describe the effects of screwthreads and screen secondary wicks on the transport capability of the artery. The model describes the hydrodynamics of the circumferential flow in triangular grooves with azimuthally varying capillary menisci and liquid cross-sections. Normalized results were obtained which give the influence of evaporator heat flux on the axial heat transport capability of the arterial wick. In order to evaluate the priming behavior of composite wicks under actual load conditions, an 'inverted' glass heat pipe was designed and constructed. The results obtained from the analysis and from the tests with the glass heat pipe were applied to the OAO-C Level 5 heat pipe, and an improved correlation between predicted and measured evaporator and transport performance were obtained.

Bienart, W. B.

1973-01-01

425

Water-heating dehumidifier  

DOEpatents

A water-heating dehumidifier includes a refrigerant loop including a compressor, at least one condenser, an expansion device and an evaporator including an evaporator fan. The condenser includes a water inlet and a water outlet for flowing water therethrough or proximate thereto, or is affixed to the tank or immersed into the tank to effect water heating without flowing water. The immersed condenser design includes a self-insulated capillary tube expansion device for simplicity and high efficiency. In a water heating mode air is drawn by the evaporator fan across the evaporator to produce cooled and dehumidified air and heat taken from the air is absorbed by the refrigerant at the evaporator and is pumped to the condenser, where water is heated. When the tank of water heater is full of hot water or a humidistat set point is reached, the water-heating dehumidifier can switch to run as a dehumidifier.

Tomlinson, John J. (Knoxville, TN)

2006-04-18

426

Induction Heating Systems  

NASA Technical Reports Server (NTRS)

Induction heating technology, a magnetic non-deforming process, was developed by Langley researchers to join plastic and composite components in space. Under NASA license, Inductron Corporation uses the process to produce induction heating systems and equipment for numerous applications. The Torobonder, a portable system, comes with a number of interchangeable heads for aircraft repair. Other developments are the E Heating Head, the Toroid Joining Gun, and the Torobrazer. These products perform bonding applications more quickly, safely and efficiently than previous methods.

1991-01-01

427

NCSX Plasma Heating Methods  

SciTech Connect

The National Compact Stellarator Experiment (NCSX) has been designed to accommodate a variety of heating systems, including ohmic heating, neutral beam injection, and radio-frequency (rf). Neutral beams will provide one of the primary heating methods for NCSX. In addition to plasma heating, neutral beams are also expected to provide a means for external control over the level of toroidal plasma rotation velocity and its profile. The experimental plan requires 3 MW of 50-keV balanced neutral beam tangential injection with pulse lengths of 500 ms for initial experiments, to be upgradeable to pulse lengths of 1.5 s. Subsequent upgrades will add 3MW of neutral beam injection (NBI). This paper discusses the NCSX NBI requirements and design issues and shows how these are provided by the candidate PBX-M NBI system. In addition, estimations are given for beam heating efficiencies, scaling of heating efficiency with machine size and magnetic field level, parameter studies of the optimum beam injection tangency radius and toroidal injection location, and loss patterns of beam ions on the vacuum chamber wall to assist placement of wall armor and for minimizing the generation of impurities by the energetic beam ions. Finally, subsequent upgrades could add an additional 6 MW of rf heating by mode conversion ion Bernstein wave (MCIBW) heating, and if desired as possible future upgrades, the design also will accommodate high-harmonic fast-wave and electron cyclotron heating. The initial MCIBW heating technique and the design of the rf system lend themselves to current drive, so if current drive became desirable for any reason, only minor modifications to the heating system described here would be needed. The rf system will also be capable of localized ion heating (bulk or tail), and possiblyIBW-generated sheared flows.

H.W. Kugel, D. Spong, R. Majeski and M. Zarnstorff

2008-01-18

428

Saturn base heating handbook  

NASA Technical Reports Server (NTRS)

A handbook containing a summary of model and flight test base heating data from the S-1, S-1B, S-4, S-1C, and S-2 stages is presented. A review of the available prediction methods is included. Experimental data are provided to make the handbook a single source of Saturn base heating data which can be used for preliminary base heating design predictions of launch vehicles.

Mullen, C. R.; Bender, R. L.; Bevill, R. L.; Reardon, J.; Hartley, L.

1972-01-01

429

Waste heat economic opportunities  

Microsoft Academic Search

Recovering waste heat from compressor-station stack gases and generating steam for producing power, ethanol, gasohol, or process heat is a promising alternative-energy technology. NUS modeled four typical candidate installations - Stations A and B using gas-turbine-driven compressors, Stations C and D having reciprocating-engine prime movers. All four stations produced enough waste heat to generate either 18,000-63,000 lb\\/hr of steam or

Gault

1981-01-01

430

Heat pipe flight experiments  

NASA Technical Reports Server (NTRS)

OAO 3 heat pipe flight experiments to check out weightlessness behavior are reported. Tested were a hollow channel screen system with helical grooves, a heat pipe with a wicking system of horizontal grooves, and a spiral artery pipe with multichannel fluid return to the evaporator. Flight experiment data proved that all heat pipe geometries containing wicking systems provided uninterrupted fluid return to the condensators during weightlessness and sufficient cooling for isothermalizing optical instruments onboard OAO.

Ollendorf, S.

1973-01-01

431

Conquer heat exchanger fouling  

Microsoft Academic Search

Fouling plays a dominant role in heat exchanger performance. It is extremely important to choose the most appropriate type of heat exchanger for a particular application and adopt proper values for fouling resistance. A design practice for shell-and-tube heat exchangers that will limit fouling to a minimum and thus ensure trouble-free operation is essential. Due to the availability of specialized

1996-01-01

432

Solar heating system  

NASA Technical Reports Server (NTRS)

A system is disclosed for using solar energy to heat the interior of a structure. The system utilizes a low cost solar collector to heat a recirculating air mass which then flows through a series of interconnected ducts and passageways without the use of exterior fans or blowers. Heat is transferred from the air mass to the structure's interior and the air mass is then reheated.

Jensen, R. N. (inventor)

1977-01-01

433

Counterflow Regolith Heat Exchanger  

NASA Technical Reports Server (NTRS)

A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

Zubrin, Robert; Jonscher, Peter

2013-01-01

434

To Heat or Not to Heat?  

NSDL National Science Digital Library

Students are introduced to various types of energy with a focus on thermal energy and types of heat transfer as they are challenged to design a better travel thermos that is cost efficient, aesthetically pleasing and meets the design objective of keeping liquids hot. They base their design decisions on material properties such thermal conductivity, cost and function. These engineering and science concepts are paired with student experiences to build an understanding of heat transfer as it plays a role in their day-to-day lives. While this introduction only shows the top-level concepts surrounding the mathematics associated with heat transfer; the skills become immediately useful as students apply what they know to solve an engineering challenge.

2014-09-18

435

Heat Kills Know Your RightsPreventing Heat Illness Know the symptoms of heat illness  

E-print Network

to the weather During a heat wave you are at greater risk of getting sick. You need to watch yourselfHeat Kills Know Your RightsPreventing Heat Illness Know the symptoms of heat illness Watch-866-924-9757 Tell your supervisor if you are new to working in the heat or have had heat illness before. Stay alert

Burke, Peter

436

Heat and mass exchanger  

DOEpatents

A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

2011-06-28

437

Heat and mass exchanger  

DOEpatents

A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

2007-09-18

438

Heat transfer dynamics  

SciTech Connect

As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained.

Smith, T.M. (Marsden, Inc., Pennsauken, NJ (United States))

1994-08-01

439

Heating Different Earth Materials  

NSDL National Science Digital Library

In this activity, students will be reminded that when sunlight strikes the Earth's surface, energy is absorbed and the surface material is heated. But although the same amount of sunlight strikes different materials at a given location, they heat up at different rates. Students will use models to demonstrate conduction, convection, and radiation and to gain an understanding about what happens to create our planet's weather, ocean currents, and other types of heat transfer. They will also shine a light on four different kinds of materials to examine their different rates of heating.

Michael Passow

440

Heat flux measurements  

NASA Technical Reports Server (NTRS)

A new automated, computer controlled heat flux measurement facility is described. Continuous transient and steady-state surface heat flux values varying from about 0.3 to 6 MW/sq m over a temperature range of 100 to 1200 K can be obtained in the facility. An application of this facility is the development of heat flux gauges for continuous fast transient surface heat flux measurement on turbine blades operating in space shuttle main engine turbopumps. The facility is useful for durability testing at fast temperature transients.

Liebert, Curt H.; Weikle, Donald H.

1989-01-01

441

Heat pipe technology issues  

SciTech Connect

Critical high temperature, high power applications in space nuclear power designs are near the current state of the art of heat pipe technology in terms of power density, operating temperature, and lifetime. Recent heat pipe development work at Los Alamos National Laboratory has involved performance testing of typical space reactor heat pipe designs to power levels in excess of 19 kW/cm/sup 2/ axially and 300 W/cm/sup 2/ radially at temperatures in the 1400 to 1500 K range. Operation at conditions in the 10 kW/cm/sup 2/ range has been sustained for periods of up to 1000 hours without evidence of performance degradation. The effective length for heat transport in these heat pipes was from 1.0 to 1.5 M. Materials used were molybdenum alloys with lithium employed as the heat pipe operating fluid. Shorter, somewhat lower power, molybdenum heat pipes have been life tested at Los Alamos for periods of greater than 25,000 hours at 1700 K with lithium and 20,000 hours at 1500/sup 0/K with sodium. These life test demonstrations and the attendant performance limit investigations provide an experimental basis for heat pipe application in space reactor design and represent the current state-of-the-art of high temperature heat pipe technology.

Merrigan, M.A.

1984-04-01

442

External artery heat pipe  

NASA Technical Reports Server (NTRS)

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.

Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

1989-01-01

443

Heat Pipe Materials Compatibility  

NASA Technical Reports Server (NTRS)

An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

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

1976-01-01

444

Heat rejection system  

DOEpatents

A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

Smith, Gregory C. (Richland, WA); Tokarz, Richard D. (Richland, WA); Parry, Jr., Harvey L. (Richland, WA); Braun, Daniel J. (Richland, WA)

1980-01-01

445

Microtube strip heat exchanger  

SciTech Connect

During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and, performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling. 2 refs., 4 figs.

Doty, F.D.

1991-07-08

446

HEATS: Thermal Energy Storage  

SciTech Connect

HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

None

2012-01-01

447

Reclaiming Waste Heat  

NASA Technical Reports Server (NTRS)

'Air-O-Space' heater, based on spacecraft heat, requires no fuel other than electricity to run fan. Installed in chimney flue, heat pipes transfer heat from waste hot gases (but not the gases themselves) to fresh air blown across the other end of the pipes. It can transport roughly 500 times the heat flux of the best solid conductors with a temperature drop of less than 3 degrees per foot. This instrument has also been used by Kin-Tek Laboratories Inc. to produce an instrument to calibrate gas analyzers for air-pollution monitoring.

1976-01-01

448

Heat pipe cooled probe  

NASA Technical Reports Server (NTRS)

The basic heat pipe principle is employed to provide a self-contained passively cooled probe that may be placed into a high temperature environment. The probe consists of an evaporator region of a heat pipe and a sensing instrument. Heat is absorbed as the working fluid evaporates in the probe. The vapor is transported to the vapor space of the condenser region. Heat is dissipated from the condenser region and fins causing condensation of the working fluid, which returns to the probe by gravity and the capillary action of the wick. Working fluid, wick and condenser configurations and structure materials can be selected to maintain the probe within an acceptable temperature range.

Camarda, C. J. (inventor); Couch, L. M.

1984-01-01

449

Heat Capacity Analysis Report  

SciTech Connect

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

A. Findikakis

2004-11-01

450

Heat Pipe Integrated Microsystems  

SciTech Connect

The trend in commercial electronics packaging to deliver ever smaller component packaging has enabled the development of new highly integrated modules meeting the demands of the next generation nano satellites. At under ten kilograms, these nano satellites will require both a greater density electronics and a melding of satellite structure and function. Better techniques must be developed to remove the subsequent heat generated by the active components required to-meet future computing requirements. Integration of commercially available electronics must be achieved without the increased costs normally associated with current generation multi chip modules. In this paper we present a method of component integration that uses silicon heat pipe technology and advanced flexible laminate circuit board technology to achieve thermal control and satellite structure. The' electronics/heat pipe stack then becomes an integral component of the spacecraft structure. Thermal management on satellites has always been a problem. The shrinking size of electronics and voltage requirements and the accompanying reduction in power dissipation has helped the situation somewhat. Nevertheless, the demands for increased onboard processing power have resulted in an ever increasing power density within the satellite body. With the introduction of nano satellites, small satellites under ten kilograms and under 1000 cubic inches, the area available on which to place hot components for proper heat dissipation has dwindled dramatically. The resulting satellite has become nearly a solid mass of electronics with nowhere to dissipate heat to space. The silicon heat pipe is attached to an aluminum frame using a thermally conductive epoxy or solder preform. The frame serves three purposes. First, the aluminum frame provides a heat conduction path from the edge of the heat pipe to radiators on the surface of the satellite. Secondly, it serves as an attachment point for extended structures attached to the satellite such as solar panels, radiators, antenna and.telescopes (for communications or sensors). Finally, the packages make thermal contact to the surface of the silicon heat pipe through soft thermal pads. Electronic components can be placed on both sides of the flexible circuit interconnect. Silicon heat pipes have a number of advantages over heat pipe constructed from other materials. Silicon heat pipes offer the ability to put the heat pipe structure beneath the active components of a processed silicon wafer. This would be one way of efficiently cooling the heat generated by wafer scale integrated systems. Using this technique, all the functions of a satellite could be reduced to a few silicon wafers. The integration of the heat pipe and the electronics would further reduce the size and weight of the satellite.

Gass, K.; Robertson, P.J.; Shul, R.; Tigges, C.

1999-03-30

451

Lunar Base Heat Pump  

NASA Technical Reports Server (NTRS)

The objective of this project was to investigate the feasibility of constructing a heat pump suitable for use as a heat rejection device in applications such as a lunar base. In this situation, direct heat rejection through the use of radiators is not possible at a temperature suitable for lde support systems. Initial analysis of a heat pump of this type called for a temperature lift of approximately 378 deg. K, which is considerably higher than is commonly called for in HVAC and refrigeration applications where heat pumps are most often employed. Also because of the variation of the rejection temperature (from 100 to 381 deg. K), extreme flexibility in the configuration and operation of the heat pump is required. A three-stage compression cycle using a refrigerant such as CFC-11 or HCFC-123 was formulated with operation possible with one, two or three stages of compression. Also, to meet the redundancy requirements, compression was divided up over multiple compressors in each stage. A control scheme was devised that allowed these multiple compressors to be operated as required so that the heat pump could perform with variable heat loads and rejection conditions. A prototype heat pump was designed and constructed to investigate the key elements of the high-lift heat pump concept. Control software was written and implemented in the prototype to allow fully automatic operation. The heat pump was capable of operation over a wide range of rejection temperatures and cooling loads, while maintaining cooling water temperature well within the required specification of 40 deg. C +/- 1.7 deg. C. This performance was verified through testing.

Walker, D.; Fischbach, D.; Tetreault, R.

1996-01-01

452

Solar heating system  

SciTech Connect

A climate control system is disclosed for heating and cooling a building. The system uses solar energy for its heat source and concrete blocks for its collecting and storing material. The blocks are open faced and positioned to receive the radiation directly. An insulating enclosure is restrictably positioned to expose the blocks to the sun's radiation during the day and to enclose the blocks in the evening to trap the heat for later use. The system uses both natural and forced convection currents to transfer the heat to and from the building. In a preferred embodiment, an upper compartment with a transparent roof is built above the blocks. This compartment is comparatively small and heats quickly to high temperatures. Water pipes of the building heating system can be placed in this compartment and the heated air can be routed into the building or transmitted through a duct to the bottom of the concrete blocks to heat them. The upper compartment is particularly useful in the morning because the sun strikes it first and the heat produced can be used in the house or transmitted to the blocks to begin heating them before the sun is high enough to strike them. In addition to the insulation, the invention includes secondary walls on the exposure side of the collector, comprising transparent panels in the winter and screen louvered openings in the summer. Radiation passing through the transparent panels strikes the blocks and a hot house effect is created. When the night air is relatively cool and the days are hot, the insulating enclosure can be opened at night to pass cool air into the system to lower the temperature of the blocks so they can absorb heat from the building during the day.

Mummert, H.B.

1980-01-01

453

Planetary heat flow measurements.  

PubMed

The year 2005 marks the 35th anniversary of the Apollo 13 mission, probably the most successful failure in the history of manned spaceflight. Naturally, Apollo 13's scientific payload is far less known than the spectacular accident and subsequent rescue of its crew. Among other instruments, it carried the first instrument designed to measure the flux of heat on a planetary body other than Earth. The year 2005 also should have marked the launch of the Japanese LUNAR-A mission, and ESA's Rosetta mission is slowly approaching comet Churyumov-Gerasimenko. Both missions carry penetrators to study the heat flow from their target bodies. What is so interesting about planetary heat flow? What can we learn from it and how do we measure it?Not only the Sun, but all planets in the Solar System are essentially heat engines. Various heat sources or heat reservoirs drive intrinsic and surface processes, causing 'dead balls of rock, ice or gas' to evolve dynamically over time, driving convection that powers tectonic processes and spawns magnetic fields. The heat flow constrains models of the thermal evolution of a planet and also its composition because it provides an upper limit for the bulk abundance of radioactive elements. On Earth, the global variation of heat flow also reflects the tectonic activity: heat flow increases towards the young ocean ridges, whereas it is rather low on the old continental shields. It is not surprising that surface heat flow measurements, or even estimates, where performed, contributed greatly to our understanding of what happens inside the planets. In this article, I will review the results and the methods used in past heat flow measurements and speculate on the targets and design of future experiments. PMID:16286290

Hagermann, Axel

2005-12-15

454

Role of Nottingham and Thomson effects in heating of micro-protrusion in high-gradient accelerating structures  

NASA Astrophysics Data System (ADS)

It is widely accepted that one of the reasons for appearance of the RF breakdown which limits operation of high-gradient accelerating structures is the electron dark current [1]. This field emitted current, usually considered as a precursor of the breakdown, can be emitted from apexes of micro-protrusions on a structure surface. Therefore field and thermal processes in such protrusions deserve careful studies [2, 3]. The goal of our first study [3] was to analyze 2D process of RF field penetration inside protrusion of a metal with finite conductivity and to study corresponding Joule heating. In the current study, it is found that space charges can have a stabilizing effect on the electric field. We include a modification of the 1D model described in [4]. Moreover, we include into consideration, first, the Nottingham effect which may significantly change the protrusion heating. We also investigate the interplay between high temperature gradients and electric fields (Thomson heating).[4pt] [1] Wang and Loew, SLAC PUB 7684 October 1997.[0pt] [2] K.L. Jensen, Y.Y. Lau, D.W. Feldman, P.G. O'Shea, Phys. Rev. ST Accel. Beams 11, 081001(2008).[0pt] [3] Kashyn et al, AAC-2010.[0pt] [4] K.L. Jensen, J. LEbowitz, Y.Y. LAu, J. Luginsland, Journal of Applied Physics 111, 054917(2012).

Keser, Aydin; Nusinovich, Gregory; Kashyn, Dmytro; Antonsen, Thomas

2012-10-01

455

Heat Transfer Discussion: "Heat Transfer and Wall  

E-print Network

flow boiling curve extending from the single-phase region at point C to the fully developed boiling During Subcooled Flow Nucleate Boiling­A Review" (Warrier, G.R., and Dhir, V.K., 2006, Journal of Heat in the partial boiling region, along with Eqs. 13 - 14 . The authors of 1 further state that Kandlikar 3 in 1998

Kandlikar, Satish

456

Heat pipes and use of heat pipes in furnace exhaust  

DOEpatents

An array of a plurality of heat pipe are mounted in spaced relationship to one another with the hot end of the heat pipes in a heated environment, e.g. the exhaust flue of a furnace, and the cold end outside the furnace. Heat conversion equipment is connected to the cold end of the heat pipes.

Polcyn, Adam D. (Pittsburgh, PA)

2010-12-28

457

Proceedings of Heat Transfer 2003: ASME Summer Heat Transfer Conference  

E-print Network

Proceedings of Heat Transfer 2003: ASME Summer Heat Transfer Conference Las Vegas, Nevada, USA July 21-23, 2003 HT2003-47449 HEAT TRANSFER FROM A MOVING AND EVAPORATING MENISCUS ON A HEATED SURFACE meniscus with complete evaporation of water without any meniscus break-up. The experimental heat transfer

Kandlikar, Satish