National Library of Energy BETA

Sample records for gradients thermal conductivity

  1. Method and apparatus for producing a carbon based foam article having a desired thermal-conductivity gradient

    DOE Patents [OSTI]

    Klett, James W. [Knoxville, TN; Cameron, Christopher Stan [Sanford, NC

    2010-03-02

    A carbon based foam article is made by heating the surface of a carbon foam block to a temperature above its graphitizing temperature, which is the temperature sufficient to graphitize the carbon foam. In one embodiment, the surface is heated with infrared pulses until heat is transferred from the surface into the core of the foam article such that the graphitizing temperature penetrates into the core to a desired depth below the surface. The graphitizing temperature is maintained for a time sufficient to substantially entirely graphitize the portion of the foam article from the surface to the desired depth below the surface. Thus, the foam article is an integral monolithic material that has a desired conductivity gradient with a relatively high thermal conductivity in the portion of the core that was graphitized and a relatively low thermal conductivity in the remaining portion of the foam article.

  2. Thermal Gradient Holes | Open Energy Information

    Open Energy Info (EERE)

    Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Thermal Gradient Holes Details Activities (67) Areas (48) Regions (4) NEPA(33) Exploration...

  3. Category:Thermal Gradient Holes | Open Energy Information

    Open Energy Info (EERE)

    in category "Thermal Gradient Holes" This category contains only the following page. T Thermal Gradient Holes Retrieved from "http:en.openei.orgwindex.php?titleCategory:T...

  4. Thermal Gradient Holes At Chocolate Mountains Area (Alm, Et Al...

    Open Energy Info (EERE)

    Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes "Shallow temperature gradient drilling began at the CMAGR in January of 2010. 13 temperature...

  5. Thermal conductivity of semitransparent materials

    SciTech Connect (OSTI)

    Fine, H.A.; Jury, S.H.; McElroy, D.L.; Yarbrough, D.W.

    1981-01-01

    The three-region approximate solution for coupled conductive and radiative heat transfer and an exact solution for uncoupled conductive and radiative heat transfer in a grey semitransparent medium bounded by infinite parallel isothermal plates are employed to establish the dependence of the apparent thermal conductivity of semitransparent materials on other material properties and boundary conditions. An application of the analyses which uses apparent thermal conductivity versus density data to predict the dependence of apparent thermal conductivity on temperature is demonstrated. The predictions for seven sets of R-11 fiberglass and rock wool insulations agree with published measured values to within the limits of experimental error (+- 3%). Agreement for three sets of R-19 fiberglass insulations was, however, not good.

  6. Thermal Gradient Holes At North Brawley Geothermal Area (Matlick...

    Open Energy Info (EERE)

    DOE-funding Unknown Exploration Basis Thermal gradient wells were drilled for initial exploration and assessment of the North Brawley Geothermal Area. Notes Union Oil Company...

  7. Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    Long Valley Caldera Geothermal Area (Conservation, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Long Valley...

  8. Thermal Gradient Holes At North Brawley Geothermal Area (Edmunds...

    Open Energy Info (EERE)

    Edmunds & W., 1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At North Brawley Geothermal Area (Edmunds & W., 1977)...

  9. Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank...

    Open Energy Info (EERE)

    Exploration Basis Thermal gradient holes were drilled in an effort to determine the feasibility of commercial geothermal energy generation at Blue Mountain Notes Ten temperature...

  10. Thermal Gradient Holes At Pilgrim Hot Springs Area (DOE GTP)...

    Open Energy Info (EERE)

    Pilgrim Hot Springs Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Pilgrim Hot Springs Area (DOE GTP)...

  11. Thermal Gradient Holes At San Emidio Desert Area (DOE GTP) |...

    Open Energy Info (EERE)

    San Emidio Desert Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At San Emidio Desert Area (DOE GTP)...

  12. Thermal Gradient Holes At Newberry Caldera Area (DOE GTP) | Open...

    Open Energy Info (EERE)

    Newberry Caldera Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Newberry Caldera Area (DOE GTP)...

  13. Thermal Gradient Holes At Flint Geothermal Area (DOE GTP) | Open...

    Open Energy Info (EERE)

    Flint Geothermal Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Flint Geothermal Area (DOE GTP)...

  14. Thermal Gradient Holes At Mcgee Mountain Area (DOE GTP) | Open...

    Open Energy Info (EERE)

    Mcgee Mountain Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Mcgee Mountain Area (DOE GTP) Exploration...

  15. Thermal Gradient Holes At Mccoy Geothermal Area (DOE GTP) | Open...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Mccoy Geothermal Area (DOE GTP) Exploration Activity Details...

  16. Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski,...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Exploration Activity...

  17. Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et Al., 2004) Exploration Activity...

  18. Thermal Gradient Holes At Kilauea East Rift Geothermal Area ...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea East Rift Geothermal Area (Thomas, 1986) Exploration...

  19. Thermal Gradient Holes At Mt Princeton Hot Springs Geothermal...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Mt Princeton Hot Springs Geothermal Area (Held & Henderson, 2012)...

  20. Thermal Gradient Holes At Glass Mountain Area (Cumming And Mackie...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Glass Mountain Area (Cumming And Mackie, 2007) Exploration Activity...

  1. Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP)...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) Exploration Activity Details...

  2. Testing thermal gradient driving force for grain boundary migration using molecular dynamics simulations

    SciTech Connect (OSTI)

    Bai, Xian-Ming; Zhang, Yongfeng; Tonks, Michael R.

    2015-02-01

    Strong thermal gradients in low-thermal-conductivity ceramics may drive extended defects, such as grain boundaries and voids, to migrate in preferential directions. In this work, molecular dynamics simulations are conducted to study thermal gradient driven grain boundary migration and to verify a previously proposed thermal gradient driving force equation, using uranium dioxide as a model system. It is found that a thermal gradient drives grain boundaries to migrate up the gradient and the migration velocity increases under a constant gradient owing to the increase in mobility with temperature. Different grain boundaries migrate at very different rates due to their different intrinsic mobilities. The extracted mobilities from the thermal gradient driven simulations are compared with those calculated from two other well-established methods and good agreement between the three different methods is found, demonstrating that the theoretical equation of the thermal gradient driving force is valid, although a correction of one input parameter should be made. The discrepancy in the grain boundary mobilities between modeling and experiments is also discussed.

  3. Effective thermal conductivity in thermoelectric materials

    SciTech Connect (OSTI)

    Baranowski, LL; Snyder, GJ; Toberer, ES

    2013-05-28

    Thermoelectric generators (TEGs) are solid state heat engines that generate electricity from a temperature gradient. Optimizing these devices for maximum power production can be difficult due to the many heat transport mechanisms occurring simultaneously within the TEG. In this paper, we develop a model for heat transport in thermoelectric materials in which an "effective thermal conductivity" (kappa(eff)) encompasses both the one dimensional steady-state Fourier conduction and the heat generation/consumption due to secondary thermoelectric effects. This model is especially powerful in that the value of kappa(eff) does not depend upon the operating conditions of the TEG but rather on the transport properties of the TE materials themselves. We analyze a variety of thermoelectric materials and generator designs using this concept and demonstrate that kappa(eff) predicts the heat fluxes within these devices to 5% of the exact value. (C) 2013 AIP Publishing LLC.

  4. Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    consisting of several holes including: The CH8-10 thermal-gradient holes drilled by the U.S. Geological Survey prior to 1978 to relatively shallow depths ranging from about 55 to...

  5. Thermal conductivity measurements of Summit polycrystalline silicon.

    SciTech Connect (OSTI)

    Clemens, Rebecca; Kuppers, Jaron D.; Phinney, Leslie Mary

    2006-11-01

    A capability for measuring the thermal conductivity of microelectromechanical systems (MEMS) materials using a steady state resistance technique was developed and used to measure the thermal conductivities of SUMMiT{trademark} V layers. Thermal conductivities were measured over two temperature ranges: 100K to 350K and 293K to 575K in order to generate two data sets. The steady state resistance technique uses surface micromachined bridge structures fabricated using the standard SUMMiT fabrication process. Electrical resistance and resistivity data are reported for poly1-poly2 laminate, poly2, poly3, and poly4 polysilicon structural layers in the SUMMiT process from 83K to 575K. Thermal conductivity measurements for these polysilicon layers demonstrate for the first time that the thermal conductivity is a function of the particular SUMMiT layer. Also, the poly2 layer has a different variation in thermal conductivity as the temperature is decreased than the poly1-poly2 laminate, poly3, and poly4 layers. As the temperature increases above room temperature, the difference in thermal conductivity between the layers decreases.

  6. Electrical and thermal conductivities in dense plasmas

    SciTech Connect (OSTI)

    Faussurier, G. Blancard, C.; Combis, P.; Videau, L.

    2014-09-15

    Expressions for the electrical and thermal conductivities in dense plasmas are derived combining the Chester-Thellung-Kubo-Greenwood approach and the Kramers approximation. The infrared divergence is removed assuming a Drude-like behaviour. An analytical expression is obtained for the Lorenz number that interpolates between the cold solid-state and the hot plasma phases. An expression for the electrical resistivity is proposed using the Ziman-Evans formula, from which the thermal conductivity can be deduced using the analytical expression for the Lorenz number. The present method can be used to estimate electrical and thermal conductivities of mixtures. Comparisons with experiment and quantum molecular dynamics simulations are done.

  7. Increased thermal conductivity monolithic zeolite structures

    DOE Patents [OSTI]

    Klett, James (Knoxville, TN); Klett, Lynn (Knoxville, TN); Kaufman, Jonathan (Leonardtown, MD)

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  8. Evaluation of thermal gradients in longitudinal spin Seebeck effect measurements

    SciTech Connect (OSTI)

    Sola, A. Kuepferling, M.; Basso, V.; Pasquale, M.; Kikkawa, T.; Uchida, K.; Saitoh, E.

    2015-05-07

    In the framework of the longitudinal spin Seebeck effect (LSSE), we developed an experimental setup for the characterization of LSSE devices. This class of device consists in a layered structure formed by a substrate, a ferrimagnetic insulator (YIG) where the spin current is thermally generated, and a paramagnetic metal (Pt) for the detection of the spin current via the inverse spin-Hall effect. In this kind of experiments, the evaluation of a thermal gradient through the thin YIG layer is a crucial point. In this work, we perform an indirect determination of the thermal gradient through the measurement of the heat flux. We developed an experimental setup using Peltier cells that allow us to measure the heat flux through a given sample. In order to test the technique, a standard LSSE device produced at Tohoku University was measured. We find a spin Seebeck S{sub SSE} coefficient of 2.810{sup ?7} V K{sup ?1}.

  9. Thermal conductivity of tubrostratic carbon nanofiber networks

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bauer, Matthew L.; Saltonstall, Chris B.; Leseman, Zayd C.; Beechem, Thomas E.; Hopkins, Patrick E.; Norris, Pamela M.

    2016-01-01

    Composite material systems composed of a matrix of nano materials can achieve combinations of mechanical and thermophysical properties outside the range of traditional systems. While many reports have studied the intrinsic thermal properties of individual carbon fibers, to be useful in applications in which thermal stability is critical, an understanding of heat transport in composite materials is required. In this work, air/ carbon nano fiber networks are studied to elucidate the system parameters influencing thermal transport. Sample thermal properties are measured with varying initial carbon fiber fill fraction, environment pressure, loading pressure, and heat treatment temperature through a bidirectional modificationmore » of the 3ω technique. The nanostructures of the individual fibers are characterized with small angle x-ray scattering and Raman spectroscopy providing insight to individual fiber thermal conductivity. Measured thermal conductivity varied from 0.010 W/(m K) to 0.070 W/(m K). An understanding of the intrinsic properties of the individual fibers and the interactions of the two phase composite is used to reconcile low measured thermal conductivities with predictive modeling. This methodology can be more generally applied to a wide range of fiber composite materials and their applications.« less

  10. Gas storage carbon with enhanced thermal conductivity

    DOE Patents [OSTI]

    Burchell, Timothy D. (Oak Ridge, TN); Rogers, Michael Ray (Knoxville, TN); Judkins, Roddie R. (Knoxville, TN)

    2000-01-01

    A carbon fiber carbon matrix hybrid adsorbent monolith with enhanced thermal conductivity for storing and releasing gas through adsorption and desorption is disclosed. The heat of adsorption of the gas species being adsorbed is sufficiently large to cause hybrid monolith heating during adsorption and hybrid monolith cooling during desorption which significantly reduces the storage capacity of the hybrid monolith, or efficiency and economics of a gas separation process. The extent of this phenomenon depends, to a large extent, on the thermal conductivity of the adsorbent hybrid monolith. This invention is a hybrid version of a carbon fiber monolith, which offers significant enhancements to thermal conductivity and potential for improved gas separation and storage systems.

  11. Thermal lens elimination by gradient-reduced zone coupling of optical beams

    DOE Patents [OSTI]

    Page, Ralph H. (San Ramon, CA); Beach, Raymond J. (Livermore, CA)

    2000-01-01

    A thermal gradient-reduced-zone laser includes a laser medium and an optically transparent plate with an index of refraction that is less than the index of refraction of the laser medium. The pump face of the laser medium is bonded to a surface of the optically transparent member. Pump light is directed through the transparent plate to optically pump the solid state laser medium. Heat conduction is mainly through the surface of the laser medium where the heat is introduced by the pump light. Heat flows in a direction opposite to that of the pump light because the side of the laser medium that is opposite to that of the pump face is not in thermal contact with a conductor and thus there is no heat flux (and hence, no temperature gradient), thus producing a thermal gradient-reduced zone. A laser cavity is formed around the laser medium such that laser light oscillating within the laser cavity reflects by total-internal-reflection from the interface between the pump face and the optically transparent plate and enters and exits through a thermal gradient-reduced zone.

  12. Glass-like thermal conductivity in high efficiency thermoelectric...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Glass-like thermal conductivity in high efficiency thermoelectric materials Glass-like thermal conductivity in high efficiency thermoelectric materials Discusses strategies to...

  13. Measuring Thermal Conductivity with Raman:Capability Uncertainty...

    Office of Scientific and Technical Information (OSTI)

    Measuring Thermal Conductivity with Raman:Capability Uncertainty and Strain Effects. Citation Details In-Document Search Title: Measuring Thermal Conductivity with Raman:Capability...

  14. Method for determining thermal conductivity and thermal capacity per unit volume of earth in situ

    DOE Patents [OSTI]

    Poppendiek, Heinz F. (LaJolla, CA)

    1982-01-01

    A method for determining the thermal conductivity of the earth in situ is based upon a cylindrical probe (10) having a thermopile (16) for measuring the temperature gradient between sets of thermocouple junctions (18 and 20) of the probe after it has been positioned in a borehole and has reached thermal equilibrium with its surroundings, and having means (14) for heating one set of thermocouple junctions (20) of the probe at a constant rate while the temperature gradient of the probe is recorded as a rise in temperature over several hours (more than about 3 hours). A fluid annulus thermally couples the probe to the surrounding earth. The recorded temperature curves are related to the earth's thermal conductivity, k.sub..infin., and to the thermal capacity per unit volume, (.gamma.c.sub.p).sub..infin., by comparison with calculated curves using estimates of k.sub..infin. and (.gamma.c.sub.p).sub..infin. in an equation which relates these parameters to a rise in the earth's temperature for a known and constant heating rate.

  15. Differential heating: A versatile method for thermal conductivity measurements in high-energy-density matter

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ping, Y.; Fernandez-Panella, A.; Sio, H.; Correa, A.; Shepherd, R.; Landen, O.; London, R. A.; Sterne, P. A.; Whitley, H. D.; Fratanduono, D.; et al

    2015-09-04

    We propose a method for thermal conductivity measurements of high energy density matter based on differential heating. A temperature gradient is created either by surface heating of one material or at an interface between two materials by different energy deposition. The subsequent heat conduction across the temperature gradient is observed by various time-resolved probing techniques. Conceptual designs of such measurements using laser heating, proton heating, and x-ray heating are presented. As a result, the sensitivity of the measurements to thermal conductivity is confirmed by simulations.

  16. Los Alamos probes mysteries of uranium dioxide's thermal conductivity

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Mysteries of uranium dioxide's thermal conductivity Los Alamos probes mysteries of uranium dioxide's thermal conductivity New research is showing that the thermal conductivity of cubic uranium dioxide is strongly affected by interactions between phonons carrying heat and magnetic spins. August 4, 2014 Illustration of anisotropic thermal conductivity in uranium dioxide (UO2). Scientists are studying the thermal conductivity related to the material's different crystallographic directions, hoping

  17. Growth of large aluminum nitride single crystals with thermal-gradient control

    DOE Patents [OSTI]

    Bondokov, Robert T; Rao, Shailaja P; Gibb, Shawn Robert; Schowalter, Leo J

    2015-05-12

    In various embodiments, non-zero thermal gradients are formed within a growth chamber both substantially parallel and substantially perpendicular to the growth direction during formation of semiconductor crystals, where the ratio of the two thermal gradients (parallel to perpendicular) is less than 10, by, e.g., arrangement of thermal shields outside of the growth chamber.

  18. Inherent Errors Associated with Raman Based Thermal Conductivity...

    Office of Scientific and Technical Information (OSTI)

    Inherent Errors Associated with Raman Based Thermal Conductivity Measurements. Citation Details In-Document Search Title: Inherent Errors Associated with Raman Based Thermal...

  19. Thermal Gradient Holes At Fish Lake Valley Area (DOE GTP) | Open...

    Open Energy Info (EERE)

    Fish Lake Valley Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fish Lake Valley Area (DOE GTP)...

  20. Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al...

    Open Energy Info (EERE)

    Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010)...

  1. Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management...

    Open Energy Info (EERE)

    Salt Wells Area (Bureau of Land Management, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Salt Wells Area...

  2. Thermal Gradient Holes At Hot Pot Area (DOE GTP) | Open Energy...

    Open Energy Info (EERE)

    Pot Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hot Pot Area (DOE GTP) Exploration Activity Details...

  3. Thermal Gradient Holes At Fort Bliss Area (DOE GTP) | Open Energy...

    Open Energy Info (EERE)

    Bliss Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fort Bliss Area (DOE GTP) Exploration Activity...

  4. Thermal Gradient Holes At Alum Area (DOE GTP) | Open Energy Informatio...

    Open Energy Info (EERE)

    Alum Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Alum Area (DOE GTP) Exploration Activity Details...

  5. Thermal Gradient Holes At Silver Peak Area (DOE GTP) | Open Energy...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Silver Peak Area (DOE GTP) Exploration Activity Details Location...

  6. Thermal Gradient Holes At Kilauea East Rift Area (Quane, Et Al...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea East Rift Area (Quane, Et Al., 2000) Exploration Activity...

  7. Experimental and numerical study of the effective thermal conductivity of

    Office of Scientific and Technical Information (OSTI)

    silica nanocomposites with thermal boundary resistance (Journal Article) | SciTech Connect Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance Citation Details In-Document Search Title: Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance The thermal interface resistance at the macro scale is mainly described by the physical gap between two

  8. Thermal Gradient Holes At Waunita Hot Springs Geothermal Area...

    Open Energy Info (EERE)

    crust. The boreholes which exhibited the lowest average gradient were several kilometers from the hot springs and up-dip. None of them penetrated the Dakota Sandstone ....

  9. Thermal Gradient Holes At Tungsten Mountain Area (Kratt, Et Al...

    Open Energy Info (EERE)

    Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes twenty-three gold exploration holes were drilled by Newcrest Resources, Inc. during 2005 and 2006 along...

  10. Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010...

    Open Energy Info (EERE)

    Unknown Notes The Navy recently completed a temperature gradient hole (TGH) drilling campaign. Results suggest multiple resources may exist on HAD lands. To further define the...

  11. Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski,...

    Open Energy Info (EERE)

    Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes Update to Warpinski, et al., 2002 References N. R. Warpinski, A. R. Sattler, R. Fortuna, D....

  12. Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al.,...

    Open Energy Info (EERE)

    Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes Update to Warpinski, et al., 2002 References N. R. Warpinski, A. R. Sattler, R. Fortuna, D....

  13. Measurement of thermal conductivity in proton irradiated silicon (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Measurement of thermal conductivity in proton irradiated silicon Citation Details In-Document Search Title: Measurement of thermal conductivity in proton irradiated silicon We investigate the influence of proton irradiation on thermal conductivity in single crystal silicon. We apply laser based modulated thermoreflectance technique to extract the change in conductivity of the thin layer damaged by proton irradiation. Unlike time domain thermoreflectance techniques

  14. Thermal Gradient Holes At Neal Hot Springs Geothermal Area (U...

    Open Energy Info (EERE)

    small diameter temperature gradient wells have been drilled ranging in depth from 152-607 m. These wells were drilled across the Neal Hot Springs area in order to gather more...

  15. Thermal Gradient Holes At Coso Geothermal Area (1976) | Open...

    Open Energy Info (EERE)

    to depths up to 133 m in 22 boreholes with measurements being made at least four times in each borehole. Geothermal gradients ranged from 240Ckm to 450 0Ckm. References...

  16. Glass-like thermal conductivity in high efficiency thermoelectric materials

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    | Department of Energy Glass-like thermal conductivity in high efficiency thermoelectric materials Glass-like thermal conductivity in high efficiency thermoelectric materials Discusses strategies to design thermoelectric materials with extremely low lattice thermal conductivity through modifications of the phonon band structure and phonon relaxation time. PDF icon toberer.pdf More Documents & Publications NSF/DOE Thermoelectrics Partnership: Thermoelectrics for Automotive Waste Heat

  17. Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets

    Office of Energy Efficiency and Renewable Energy (EERE)

    Project to develop and validate a continuous manufacturing process for polyethylene fibers and sheets yielding a thermal conductivity value greater than 60 W/m.K.

  18. Abnormal thermal conductivity in tetragonal tungsten bronze Ba...

    Office of Scientific and Technical Information (OSTI)

    temperature interval. Substitution of Sr for Ba brings about a significant decrease in thermal conductivity at x???3 accompanied by development of a low-temperature...

  19. Development of a Test Technique to Determine the Thermal Conductivity...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Development of a Test Technique to Determine the Thermal Conductivity of Large Refractory Ceramic Test Specimens Citation Details In-Document Search Title: ...

  20. Specific heat and thermal conductivity of explosives, mixtures...

    Office of Scientific and Technical Information (OSTI)

    Specific heat and thermal conductivity of explosives, mixtures, and plastic-bonded explosives determined experimentally Baytos, J.F. 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL...

  1. Heat diode effect and negative differential thermal conductance...

    Office of Scientific and Technical Information (OSTI)

    Heat diode effect and negative differential thermal conductance across nanoscale metal-dielectric interfaces Citation Details In-Document Search Title: Heat diode effect and...

  2. Continuous Processing of High Thermal Conductivity Polyethylene...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    conductivity polyethylene fibers and sheets will be developed to replace metals and ceramics in heat-transfer devices. Project innovations include using massively parallel...

  3. Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al...

    Open Energy Info (EERE)

    while 5 wells reached depths of 600 - 1020 feet. References Kamil Erkan, Gwen Holdman, David Blackwell, Walter Benoit (2007) Thermal Characteristics of the Chena Hot Springs...

  4. Thermal Gradient Holes At Breitenbush Hot Springs Area (Ingebritsen...

    Open Energy Info (EERE)

    (1993) Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Additional References Retrieved from "http:en.openei.orgwindex.php?titleThermalGr...

  5. THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS

    SciTech Connect (OSTI)

    ALLAN,M.

    1998-05-01

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  6. Measurement of thermal conductivity in proton irradiated silicon

    SciTech Connect (OSTI)

    Marat Khafizov; Clarissa Yablinsky; Todd Allen; David Hurley

    2014-04-01

    We investigate the influence of proton irradiation on thermal conductivity in single crystal silicon. We apply laser based modulated thermoreflectance technique to extract the change in conductivity of the thin layer damaged by proton irradiation. Unlike time domain thermoreflectance techniques that require application of a metal film, we perform our measurement on uncoated samples. This provides greater sensitivity to the change in conductivity of the thin damaged layer. Using sample temperature as a parameter provides a means to deduce the primary defect structures that limit thermal transport. We find that under high temperature irradiation the degradation of thermal conductivity is caused primarily by extended defects.

  7. Theoretical investigation of the impact of grain boundaries and fission gases on UO2 thermal conductivity

    SciTech Connect (OSTI)

    Du, Shiyu; Andersson, Anders D.; Germann, Timothy C.; Stanek, Christopher R.

    2012-05-02

    Thermal conductivity is one of the most important metrics of nuclear fuel performance. Therefore, it is crucial to understand the impact of microstructure features on thermal conductivity, especially since the microstructure evolves with burn-up or time in the reactor. For example, UO{sub 2} fuels are polycrystalline and for high-burnup fuels the outer parts of the pellet experience grain sub-division leading to a very fine grain structure. This is known to impact important physical properties such as thermal conductivity as fission gas release. In a previous study, we calculated the effect of different types of {Sigma}5 grain boundaries on UO{sub 2} thermal conductivity and predicted the corresponding Kapitza resistances, i.e. the resistance of the grain boundary in relation to the bulk thermal resistance. There have been reports of pseudoanisotropic effects for the thermal conductivity in cubic polycrystalline materials, as obtained from molecular dynamics simulations, which means that the conductivity appears to be a function of the crystallographic direction of the temperature gradient. However, materials with cubic symmetry should have isotropic thermal conductivity. For this reason it is necessary to determine the cause of this apparent anisotropy and in this report we investigate this effect in context of our earlier simulations of UO{sub 2} Kapitza resistances. Another source of thermal resistance comes from fission products and fission gases. Xe is the main fission gas and when generated in sufficient quantity it dissolves from the lattice and forms gas bubbles inside the crystalline structure. We have performed studies of how Xe atoms dissolved in the UO{sub 2} matrix or precipitated as bubbles impact thermal conductivity, both in bulk UO{sub 2} and in the presence of grain boundaries.

  8. Microstructure changes and thermal conductivity reduction in UO2 following

    Office of Scientific and Technical Information (OSTI)

    3.9 MeV He2+ ion irradiation (Journal Article) | SciTech Connect Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation Citation Details In-Document Search Title: Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in

  9. Inherent Errors Associated with Raman Based Thermal Conductivity

    Office of Scientific and Technical Information (OSTI)

    Measurements. (Conference) | SciTech Connect Inherent Errors Associated with Raman Based Thermal Conductivity Measurements. Citation Details In-Document Search Title: Inherent Errors Associated with Raman Based Thermal Conductivity Measurements. Abstract not provided. Authors: Yates, Luke ; Beechem Iii, Thomas Edwin Publication Date: 2012-09-01 OSTI Identifier: 1116452 Report Number(s): SAND2012-7840C 480433 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation:

  10. Measuring Thermal Conductivity with Raman:Capability Uncertainty and Strain

    Office of Scientific and Technical Information (OSTI)

    Effects. (Conference) | SciTech Connect Measuring Thermal Conductivity with Raman:Capability Uncertainty and Strain Effects. Citation Details In-Document Search Title: Measuring Thermal Conductivity with Raman:Capability Uncertainty and Strain Effects. Abstract not provided. Authors: Beechem Iii, Thomas Edwin ; Yates, Luke Publication Date: 2012-11-01 OSTI Identifier: 1116156 Report Number(s): SAND2012-10198C 480178 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource

  11. Controlling thermal conductance through quantum dot roughening at

    Office of Scientific and Technical Information (OSTI)

    interfaces. (Journal Article) | SciTech Connect Journal Article: Controlling thermal conductance through quantum dot roughening at interfaces. Citation Details In-Document Search Title: Controlling thermal conductance through quantum dot roughening at interfaces. Abstract not provided. Authors: Hopkins, Patrick Edward ; Duda, John C. ; Petz, Christopher W. ; Floro, Jerrold A. Publication Date: 2011-01-01 OSTI Identifier: 1110382 Report Number(s): SAND2011-0398J 473795 DOE Contract Number:

  12. Evidence of ion mixing increasing the thermal boundary conductance across

    Office of Scientific and Technical Information (OSTI)

    aluminum/silicon interfaces. (Journal Article) | SciTech Connect Evidence of ion mixing increasing the thermal boundary conductance across aluminum/silicon interfaces. Citation Details In-Document Search Title: Evidence of ion mixing increasing the thermal boundary conductance across aluminum/silicon interfaces. Abstract not provided. Authors: Hattar, Khalid Mikhiel ; Beechem Iii, Thomas Edwin ; Ihlefeld, Jon F. ; Biedermann, Laura Butler ; Piekos, Edward Stanley ; Medlin, Douglas L. [1] ;

  13. Resonant bonding leads to low lattice thermal conductivity (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Resonant bonding leads to low lattice thermal conductivity Citation Details In-Document Search Title: Resonant bonding leads to low lattice thermal conductivity Authors: Lee, S Y ; Esfarjani, Keivan ; Luo, T. ; Zhou, J ; Tian, Z ; Chen, Gang Publication Date: 2014-04-28 OSTI Identifier: 1161924 DOE Contract Number: SC0001299; FG02-09ER46577 Resource Type: Journal Article Resource Relation: Journal Name: Nature Communications; Journal Volume: 5; Related Information:

  14. Strain Effects in Raman Thermal Conductivity Measurements. (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Strain Effects in Raman Thermal Conductivity Measurements. Citation Details In-Document Search Title: Strain Effects in Raman Thermal Conductivity Measurements. Abstract not provided. Authors: Beechem Iii, Thomas Edwin ; Yates, Luke Publication Date: 2012-11-01 OSTI Identifier: 1116178 Report Number(s): SAND2012-10199C 480179 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: Society of Engineering Sciences Conference held October

  15. Next-Generation LED Package Architectures Enabled by Thermally Conductive

    Energy Savers [EERE]

    Transparent Encapsulants | Department of Energy LED Package Architectures Enabled by Thermally Conductive Transparent Encapsulants Next-Generation LED Package Architectures Enabled by Thermally Conductive Transparent Encapsulants Lead Performer: Momentive Performance Materials Quartz, Inc. DOE Total Funding: $1,497,255 Cost Share: $512,700 Project Term: 10/1/2014 - 3/31/2016 Funding Opportunity: SSL R&D Funding Opportunity Announcement (FOA) (DE-FOA-0000973) Project Objective This

  16. Novel Transparent Phosphor Conversion Matrix with High Thermal Conductivity

    Energy Savers [EERE]

    for Next-Generation Phosphor-Converted LED-based Solid State Lighting | Department of Energy Novel Transparent Phosphor Conversion Matrix with High Thermal Conductivity for Next-Generation Phosphor-Converted LED-based Solid State Lighting Novel Transparent Phosphor Conversion Matrix with High Thermal Conductivity for Next-Generation Phosphor-Converted LED-based Solid State Lighting Lead Performer: Carnegie Mellon University - Pittsburgh, PA Partners: Osram Sylvania - Danvers, MA DOE Total

  17. Magneto-Seebeck effect in spin-valve with in-plane thermal gradient

    SciTech Connect (OSTI)

    Jain, S. Bose, A. Palkar, V. R. Tulapurkar, A. A.; Lam, D. D. Suzuki, Y.; Sharma, H. Tomy, C. V.

    2014-12-15

    We present measurements of magneto-Seebeck effect on a spin valve with in-plane thermal gradient. We measured open circuit voltage and short circuit current by applying a temperature gradient across a spin valve stack, where one of the ferromagnetic layers is pinned. We found a clear hysteresis in these two quantities as a function of magnetic field. From these measurements, the magneto-Seebeck effect was found to be same as magneto-resistance effect.

  18. Millisecond ordering of block-copolymer films via photo-thermal gradients

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Majewski, Pawel W.; Yager, Kevin G.

    2015-03-12

    For the promise of self-assembly to be realized, processing techniques must be developed that simultaneously enable control of the nanoscale morphology, rapid assembly, and, ideally, the ability to pattern the nanostructure. Here, we demonstrate how photo-thermal gradients can be used to control the ordering of block-copolymer thin films. Highly localized laser heating leads to intense thermal gradients, which induce a thermophoretic force on morphological defects. This increases the ordering kinetics by at least 3 orders-of-magnitude, compared to conventional oven annealing. By simultaneously exploiting the thermal gradients to induce shear fields, we demonstrate uniaxial alignment of a block-copolymer film in lessmore » than a second. Finally, we provide examples of how control of the incident light-field can be used to generate prescribed configurations of block-copolymer nanoscale patterns.« less

  19. Generalized Procedure for Improved Accuracy of Thermal Contact Resistance Measurements for Materials With Arbitrary Temperature-Dependent Thermal Conductivity

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sayer, Robert A.

    2014-06-26

    Thermal contact resistance (TCR) is most commonly measured using one-dimensional steady-state calorimetric techniques. In the experimental methods we utilized, a temperature gradient is applied across two contacting beams and the temperature drop at the interface is inferred from the temperature profiles of the rods that are measured at discrete points. During data analysis, thermal conductivity of the beams is typically taken to be an average value over the temperature range imposed during the experiment. Our generalized theory is presented and accounts for temperature-dependent changes in thermal conductivity. The procedure presented enables accurate measurement of TCR for contacting materials whose thermalmore » conductivity is any arbitrary function of temperature. For example, it is shown that the standard technique yields TCR values that are about 15% below the actual value for two specific examples of copper and silicon contacts. Conversely, the generalized technique predicts TCR values that are within 1% of the actual value. The method is exact when thermal conductivity is known exactly and no other errors are introduced to the system.« less

  20. Process for fabricating composite material having high thermal conductivity

    DOE Patents [OSTI]

    Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

    2001-01-01

    A process for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost.

  1. Thermally conductive cementitious grout for geothermal heat pump systems

    DOE Patents [OSTI]

    Allan, Marita (Old Field, NY)

    2001-01-01

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  2. High thermal conductivity lossy dielectric using a multi layer configuration

    DOE Patents [OSTI]

    Tiegs, Terry N. (Lenoir City, TN); Kiggans, Jr., James O. (Oak Ridge, TN)

    2003-01-01

    Systems and methods are described for loss dielectrics. A loss dielectric includes at least one high dielectric loss layer and at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. A method of manufacturing a loss dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. The systems and methods provide advantages because the loss dielectrics are less costly and more environmentally friendly than the available alternatives.

  3. Pretest Caluculations of Temperature Changes for Field Thermal Conductivity Tests

    SciTech Connect (OSTI)

    N.S. Brodsky

    2002-07-17

    A large volume fraction of the potential monitored geologic repository at Yucca Mountain may reside in the Tptpll (Tertiary, Paintbrush Group, Topopah Spring Tuff, crystal poor, lower lithophysal) lithostratigraphic unit. This unit is characterized by voids, or lithophysae, which range in size from centimeters to meters. A series of thermal conductivity field tests are planned in the Enhanced Characterization of the Repository Block (ECRB) Cross Drift. The objective of the pretest calculation described in this document is to predict changes in temperatures in the surrounding rock for these tests for a given heater power and a set of thermal transport properties. The calculation can be extended, as described in this document, to obtain thermal conductivity, thermal capacitance (density x heat capacity, J {center_dot} m{sup -3} {center_dot} K{sup -1}), and thermal diffusivity from the field data. The work has been conducted under the ''Technical Work Plan For: Testing and Monitoring'' (BSC 2001). One of the outcomes of this analysis is to determine the initial output of the heater. This heater output must be sufficiently high that it will provide results in a reasonably short period of time (within several weeks or a month) and be sufficiently high that the heat increase is detectable by the instruments employed in the test. The test will be conducted in stages and heater output will be step increased as the test progresses. If the initial temperature is set too high, the experiment will not have as many steps and thus fewer thermal conductivity data points will result.

  4. Mode dependent lattice thermal conductivity of single layer graphene

    SciTech Connect (OSTI)

    Wei, Zhiyong; Yang, Juekuan; Bi, Kedong; Chen, Yunfei

    2014-10-21

    Molecular dynamics simulation is performed to extract the phonon dispersion and phonon lifetime of single layer graphene. The mode dependent thermal conductivity is calculated from the phonon kinetic theory. The predicted thermal conductivity at room temperature exhibits important quantum effects due to the high Debye temperature of graphene. But the quantum effects are reduced significantly when the simulated temperature is as high as 1000 K. Our calculations show that out-of-plane modes contribute about 41.1% to the total thermal conductivity at room temperature. The relative contribution of out-of-plane modes has a little decrease with the increase of temperature. Contact with substrate can reduce both the total thermal conductivity of graphene and the relative contribution of out-of-plane modes, in agreement with previous experiments and theories. Increasing the coupling strength between graphene and substrate can further reduce the relative contribution of out-of-plane modes. The present investigations also show that the relative contribution of different mode phonons is not sensitive to the grain size of graphene. The obtained phonon relaxation time provides useful insight for understanding the phonon mean free path and the size effects in graphene.

  5. The effect of thermal aging on the thermal conductivity of plasma sprayed and EB-PVD thermal barrier coatings

    SciTech Connect (OSTI)

    Dinwiddie, R.B.; Beecher, S.C.; Porter, W.D.; Nagaraj, B.A.

    1996-05-01

    Thermal barrier coatings (TBCs) applied to the hot gas components of turbine engines lead to enhanced fuel efficiency and component reliability. Understanding the mechanisms which control the thermal transport behavior of the TBCs is of primary importance. Electron beam-physical vapor deposition (EV-PVD) and air plasma spraying (APS) are the two most commonly used coating techniques. These techniques produce coatings with unique microstructures which control their performance and stability. The density of the APS coatings was controlled by varying the spray parameters. The low density APS yttria-partially stabilized zirconia (yttria-PSZ) coatings yielded a thermal conductivity that is lower than both the high density APS coatings and the EB-PVD coatings. The thermal aging of both fully and partially stabilized zirconia are compared. The thermal conductivity of the coatings permanently increases upon exposure to high temperatures. These increases are attributed to microstructural changes within the coatings. This increase in thermal conductivity can be modeled using a relationship which depends on both the temperature and time of exposure. Although the EB-PVD coatings are less susceptible to thermal aging effects, results suggest that they typically have a higher thermal conductivity than APS coatings before thermal aging. The increases in thermal conductivity due to thermal aging for plasma sprayed partially stabilized zirconia have been found to be less than for plasma sprayed fully stabilized zirconia coatings.

  6. Hot wire thermal conductivity measurements in high temperature refractories

    SciTech Connect (OSTI)

    Dils, R.R.; Allen, J.D.; Richmond, J.C.; McNeil, M.B.

    1982-01-01

    In the hot wire thermal conductivity test, a wire embedded in the material to be tested is heated with constant power input, and the temperature is measured at short time intervals. The thermal conductivity is computed from the known power input to the wire and the measured rate of increase in the wire temperature after about 700 s of heating. A finite-difference computer simulation of the hot wire test was developed to evaluate the effects of several variables in the properties of the materials tested and in the test procedures on the measured thermal conductivity. Equations relating the radiant heat transfer in a material to its optical properties were developed and a radiant heat transfer component was developed for the finite-difference simulation. Equations were derived to compute the spectral optical properties of a test material from the measured spectral normal-hemispherical transmittance of a sample of the material of known thickness that is thin enough to have a measurable transmittance over the wavelength range of about 500 to 20,000 nm, and the spectral near-normal hemispherical reflectance of a sample of the material thick enough to be completely opaque, over the same wavelength range. The optical extinction coefficient, and the ratio of the scattering coefficient, to the absorption coefficient, of MinK 2000 and K3000 brick were evaluated from their measured spectral transmittances and reflectances, and used to compute the radiant heat transfer component in these materials. The hot wire test measures an average thermal conductivity for all directions away from the wire in a plane normal to the wire. Extensive tests were made of MinK 2000 and K3000, and the measured values are compared to the guarded hot plate thermal conductivity, which is unidirectional normal to the face of a brick. 67 references, 31 figures, 23 tables.

  7. Effect of interfacial interactions on the thermal conductivity and interfacial thermal conductance in tungstengraphene layered structure

    SciTech Connect (OSTI)

    Jagannadham, K.

    2014-09-01

    Graphene film was deposited by microwave plasma assisted deposition on polished oxygen free high conductivity copper foils. Tungstengraphene layered film was formed by deposition of tungsten film by magnetron sputtering on the graphene covered copper foils. Tungsten film was also deposited directly on copper foil without graphene as the intermediate film. The tungstengraphenecopper samples were heated at different temperatures up to 900?C in argon atmosphere to form an interfacial tungsten carbide film. Tungsten film deposited on thicker graphene platelets dispersed on silicon wafer was also heated at 900?C to identify the formation of tungsten carbide film by reaction of tungsten with graphene platelets. The films were characterized by scanning electron microscopy, Raman spectroscopy, and x-ray diffraction. It was found that tungsten carbide film formed at the interface upon heating only above 650?C. Transient thermoreflectance signal from the tungsten film surface on the samples was collected and modeled using one-dimensional heat equation. The experimental and modeled results showed that the presence of graphene at the interface reduced the cross-plane effective thermal conductivity and the interfacial thermal conductance of the layer structure. Heating at 650 and 900?C in argon further reduced the cross-plane thermal conductivity and interface thermal conductance as a result of formation nanocrystalline tungsten carbide at the interface leading to separation and formation of voids. The present results emphasize that interfacial interactions between graphene and carbide forming bcc and hcp elements will reduce the cross-plane effective thermal conductivity in composites.

  8. Thermal conductivity in nanocrystalline-SiC/C superlattices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Habermehl, S.; Serrano, J. R.

    2015-11-17

    We reported the formation of thin film superlattices consisting of alternating layers of nitrogen-doped SiC (SiC:N) and C. Periodically terminating the SiC:N surface with a graphitic C boundary layer and controlling the SiC:N/C thickness ratio yield nanocrystalline SiC grains ranging in size from 365 to 23 nm. Frequency domain thermo-reflectance is employed to determine the thermal conductivity, which is found to vary from 35.5 W m-1 K-1 for monolithic undoped α-SiC films to 1.6 W m-1 K-1 for a SiC:N/C superlattice with a 47 nm period and a SiC:N/C thickness ratio of 11. A series conductance model is employed tomore » explain the dependence of the thermal conductivity on the superlatticestructure. Our results indicate that the thermal conductivity is more dependent on the SiC:N/C thickness ratio than the SiC:N grain size, indicative of strong boundary layerphonon scattering.« less

  9. Thermal gradient-induced forces on geodesic reference masses for LISA

    SciTech Connect (OSTI)

    Carbone, L.; Ciani, G.; Dolesi, R.; Hueller, M.; Tombolato, D.; Vitale, S.; Weber, W. J.; Cavalleri, A.

    2007-11-15

    The low frequency sensitivity of space-borne gravitational wave observatories will depend critically on the geodesic purity of the trajectories of orbiting test masses. Fluctuations in the temperature difference across the enclosure surrounding the free-falling test mass can produce noisy forces through several processes, including the radiometric effect, radiation pressure, and outgassing. We present here a detailed experimental investigation of thermal gradient-induced forces for the Laser Interferometer Space Antenna (LISA) gravitational wave mission and the LISA Pathfinder, employing high resolution torsion pendulum measurements of the torque on a LISA-like test mass suspended inside a prototype of the LISA gravitational reference sensor that will surround the test mass in orbit. The measurement campaign, accompanied by numerical simulations of the radiometric and radiation pressure effects, allows a more accurate and representative characterization of thermal-gradient forces in the specific geometry and environment relevant to LISA free-fall. The pressure dependence of the measured torques allows clear identification of the radiometric effect, in quantitative agreement with the model developed. In the limit of zero gas pressure, the measurements are most likely dominated by outgassing, but at a low level that does not threaten the current LISA noise estimate, which assumes a maximum net force per degree of temperature difference of 100(pN/K) for the overall thermal gradient-induced effects.

  10. Lattice thermal conductivity of filled skutterudites: An anharmonicity perspective

    SciTech Connect (OSTI)

    Geng, Huiyuan, E-mail: genghuiyuan@hit.edu.cn; Meng, Xianfu; Zhang, Hao; Zhang, Jian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2014-10-28

    We report a phenomenological model to calculate the high-temperature lattice thermal conductivity of filled skutterudite antimonides. The model needs no phonon resonant scattering terms. Instead, we assume that umklapp processes dominate the high-temperature phonon scattering. In order to represent the anharmonicity introduced by the filling atom, we introduce a Gaussian term into the relaxation time of the umklapp process. The developed model agrees remarkably well with the experimental results of RE{sub f}Co{sub 4}Sb{sub 12} and RE{sub f}Fe{sub 4}Sb{sub 12} (RE?=?Yb, Ba, and Ca) alloys. To further test the validity of our model, we calculate the lattice thermal conductivity of nanostructured or multi-filled skutterudites. The calculation results are also in good agreement with experiment, increasing our confidence in the developed anharmonicity model.

  11. Hot wire needle probe for thermal conductivity detection

    DOE Patents [OSTI]

    Condie, Keith Glenn; Rempe, Joy Lynn; Knudson, Darrell lee; Daw, Joshua Earl; Wilkins, Steven Curtis; Fox, Brandon S.; Heng, Ban

    2015-11-10

    An apparatus comprising a needle probe comprising a sheath, a heating element, a temperature sensor, and electrical insulation that allows thermal conductivity to be measured in extreme environments, such as in high-temperature irradiation testing. The heating element is contained within the sheath and is electrically conductive. In an embodiment, the heating element is a wire capable of being joule heated when an electrical current is applied. The temperature sensor is contained within the sheath, electrically insulated from the heating element and the sheath. The electrical insulation electrically insulates the sheath, heating element and temperature sensor. The electrical insulation fills the sheath having electrical resistance capable of preventing electrical conduction between the sheath, heating element, and temperature sensor. The control system is connected to the heating element and the temperature sensor.

  12. Study of thermal-gradient-induced migration of brine inclusions in salt. Final report

    SciTech Connect (OSTI)

    Olander, D.R.

    1984-08-01

    Natural salt deposits, which are being considered for high-level waste disposal, contain a small volume fraction of water in the form of brine inclusions distributed throughout the salt. Radioactive decay heating of the nuclear wastes will impose a temperature gradient on the surrounding salt which mobilizes the brine inclusions. Inclusions filled completely with brine (the all-liquid inclusions) migrate up the temperature gradient and eventually accumulate brine near the buried waste forms. The brine may slowly corrode or degrade the waste forms, which is undesirable. Therefore it is important to consider the migration of brine inclusions in salt under imposed temperature gradients to properly evaluate the performance of a future salt repository for nuclear wastes. The migration velocities of the inclusions were found to be dependent on temperature, temperature gradient, and inclusion shape and size. The velocities were also dictated by the interfacial mass transfer resistance at brine/solid interface. This interfacial resistance depends on the dislocation density in the crystal, which in turn, depends on the axial compressive loading of the crystal. At low axial loads, the dependence between the velocity and temperature gradient is nonlinear. At high axial loads, the interfacial resistance is reduced and the migration velocity depends linearly on the temperature gradient. All-liquid inclusions filled with mixed brines were also studied. For gas-liquid inclusions, helium, air and argon were compared. Migration studies were also conducted on single crystallites of natural salt as well as in polycrystalline natural salt samples. The behavior of the inclusions at large-ange grain boundaries was observed.

  13. THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS

    Office of Scientific and Technical Information (OSTI)

    9086 THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS FROM 20°C TO 330°C Huseyin Ozbek and Sidney L. P h i l l i p s Lawrence Berkeley Laboratory University o f California Berkeley, CA 94720 _ _ NOTICE sponsored by the United Stater Government. Neither the United Stater nor chc Umtcd Stater Department of Energy, nor any of their employees. nor any o f the11 c o n t r a ~ t ~ r i . subcontractors. or their cmploycer, makes any warranty, express or implied, or assumes any legal Itability or

  14. Continuous Processing of High Thermal Conductivity Fibers and Sheets

    Office of Environmental Management (EM)

    Professor Gang Chen, Carl Richard Soderberg Professor of Power Engineering 617-253-0006 (phone), 617-324-5545 (fax) gchen2@mit.edu U.S. DOE Advanced Manufacturing Office Peer Review Meeting Washington, D.C. May 6-7, 2014 This presentation does not contain any proprietary, confidential, or otherwise restricted information. Project Objective  Plastics are less expensive, lighter, and require less energy to process than metals; however, they have low thermal conductivity values (~0.3 W/mK) 

  15. Apparent thermal conductivity measurements by an unguarded technique

    SciTech Connect (OSTI)

    Graves, R.S.; Yarbrough, D.W.; McElroy, D.L.

    1983-01-01

    An unguarded longitudinal heat-flow apparatus for measuring the apparent thermal conductivity (lambda/sub a) of insulations was tested with mean specimen temperatures from 300 to 330/sup 0/K on samples up to 0.91 m wide, 1.52 m long, and 0.15 m thick. Heat flow is provided by a horizontal electrically heated Nichrome screen sandwiched between test samples that are bounded by temperature controlled copper plates and 9 cm of mineral fiber insulation. A determinate error analysis shows lambda/sub a/ measurement uncertainty to be less than +- 1.7% for insulating materials as thin as 3 cm. Three-dimensional thermal modeling indicates negligible error in lambda/sub a/ due to edge loss for insulations up to 7.62 cm thick when the temperature difference across the sample is measured at the sceen center. System repeatability and reproducibility were determined to be +- 0.2%. Differences of lambda/sub a/ results from the screen tester and results from the National Bureau of Standards were 0.1% for a 10-kg/m/sup 3/ Calibration Transfer Standard and 0.9% for 127-kg/m/sup 3/ fibrous glass board (SRM 1450b). Measurements on fiberglass and rock wool batt insulations showed the dependence of lambda/sub a/ on density, temperature, temperature difference, plate emittance, and heat flow direction. Results obtained for lambda/sub a/ as a function of density at 24/sup 0/C differed by less than 2% from values obtained with a guarded hot plate. These results demonstrate that this simple technique has the accuracy and sensitivity needed for useful lambda/sub a/ measurements on thermal insulating materials.

  16. Low Thermal Conductivity, High Durability Thermal Barrier Coatings for IGCC Environments

    SciTech Connect (OSTI)

    Jordan, Eric; Gell, Maurice

    2015-01-15

    Advanced thermal barrier coatings (TBC) are crucial to improved energy efficiency in next generation gas turbine engines. The use of traditional topcoat materials, e.g. yttria-stabilized zirconia (YSZ), is limited at elevated temperatures due to (1) the accelerated undesirable phase transformations and (2) corrosive attacks by calcium-magnesium-aluminum-silicate (CMAS) deposits and moisture. The first goal of this project is to use the Solution Precursor Plasma Spray (SPPS) process to further reduce the thermal conductivity of YSZ TBCs by introducing a unique microstructural feature of layered porosity, called inter-pass boundaries (IPBs). Extensive process optimization accompanied with hundreds of spray trials as well as associated SEM cross-section and laser-flash measurements, yielded a thermal conductivity as low as 0.62 Wm?K? in SPPS YSZ TBCs, approximately 50% reduction of APS TBCs; while other engine critical properties, such as cyclic durability, erosion resistance and sintering resistance, were characterized to be equivalent or better than APS baselines. In addition, modifications were introduced to SPPS TBCs so as to enhance their resistance to CMAS under harsh IGCC environments. Several mitigation approaches were explored, including doping the coatings with Al?O? and TiO?, applying a CMAS infiltration-inhibiting surface layer, and filling topcoat cracks with blocking substances. The efficacy of all these modifications was assessed with a set of novel CMAS-TBC interaction tests, and the moisture resistance was tested in a custom-built high-temperature moisture rig. In the end, the optimal low thermal conductivity TBC system was selected based on all evaluation tests and its processing conditions were documented. The optimal coating consisted on a thick inner layer of YSZ coating made by the SPPS process having a thermal conductivity 50% lower than standard YSZ coatings topped with a high temperature tolerant CMAS resistant gadolinium zirconate Coating made by the SPPS process. Noteworthy was the fact that the YSZ to GZO interface made by the SPPS process was not the failure location as had been observed in APS coatings.

  17. Ceramic materials with low thermal conductivity and low coefficients of thermal expansion

    DOE Patents [OSTI]

    Brown, Jesse (Christiansburg, VA); Hirschfeld, Deidre (Elliston, VA); Liu, Dean-Mo (Blacksburg, VA); Yang, Yaping (Blacksburg, VA); Li, Tingkai (Blacksburg, VA); Swanson, Robert E. (Blacksburg, VA); Van Aken, Steven (Blacksburg, VA); Kim, Jin-Min (Seoul, KR)

    1992-01-01

    Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.degree. C. to form solid macrostructures with near-zero bulk coefficients of thermal expansion and low thermal conductivities. Porous macrostructures of the MgCZP powders of the present invention are also formed by combination with a polymeric powder and a binding agent, and sintering at high temperatures. The porosity of the resulting macrostructures can be adjusted by varying the particle size of the polymeric powder used.

  18. Ceramic materials with low thermal conductivity and low coefficients of thermal expansion

    DOE Patents [OSTI]

    Brown, J.; Hirschfeld, D.; Liu, D.M.; Yang, Y.; Li, T.; Swanson, R.E.; Van Aken, S.; Kim, J.M.

    1992-04-07

    Compositions, having the general formula (Ca[sub x]Mg[sub 1[minus]x])Zr[sub 4](PO[sub 4])[sub 6] where x is between 0.5 and 0.99, are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850 C for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200 C to 1350 C to form solid macrostructures with near-zero bulk coefficients of thermal expansion and low thermal conductivities. Porous macrostructures of the MgCZP powders of the present invention are also formed by combination with a polymeric powder and a binding agent, and sintering at high temperatures. The porosity of the resulting macrostructures can be adjusted by varying the particle size of the polymeric powder used. 7 figs.

  19. Error and uncertainty in Raman thermal conductivity measurements...

    Office of Scientific and Technical Information (OSTI)

    Using this methodology, the accuracy and precision of the Raman-derived thermal ... Publisher: American Institute of Physics (AIP) Research Org: Sandia National Laboratories ...

  20. Reexamination of Basal Plane Thermal Conductivity of Suspended Graphene Samples Measured by Electro-Thermal Micro-Bridge Methods

    SciTech Connect (OSTI)

    Jo, Insun; Pettes, Michael; Lindsay, Lucas R; Ou, Eric; Weathers, Annie; Moore, Arden; Yao, Zhen; Shi, Li

    2015-01-01

    Thermal transport in suspended graphene samples has been measured in prior works and this work with the use of a suspended electro-thermal micro-bridge method. These measurement results are analyzed here to evaluate and eliminate the errors caused by the extrinsic thermal contact resistance. It is noted that the thermal resistance measured in a recent work increases linearly with the suspended length of the single-layer graphene samples synthesized by chemical vapor deposition (CVD), and that such a feature does not reveal the failure of Fourier s law despite the increase in the apparent thermal conductivity with length. The re-analyzed thermal conductivity of a single-layer CVD graphene sample reaches about ( 1680 180 )Wm-1K-1 at room temperature, which is close to the highest value reported for highly oriented pyrolytic graphite. In comparison, the thermal conductivity values measured for two suspended exfoliated bi-layer graphene samples are about ( 880 60 ) and ( 730 60 ) Wm-1K-1 at room temperature, and approach that of the natural graphite source above room temperature. However, the low-temperature thermal conductivities of these suspended graphene samples are still considerably lower than the graphite values, with the peak thermal conductivities shifted to much higher temperatures. Analysis of the thermal conductivity data reveals that the low temperature behavior is dominated by phonon scattering by polymer residue instead of by the lateral boundary.

  1. High thermal conductivity connector having high electrical isolation

    DOE Patents [OSTI]

    Nieman, Ralph C. (Downers Grove, IL); Gonczy, John D. (Oak Lawn, IL); Nicol, Thomas H. (St. Charles, IL)

    1995-01-01

    A method and article for providing a low-thermal-resistance, high-electrical-isolation heat intercept connection. The connection method involves clamping, by thermal interference fit, an electrically isolating cylinder between an outer metallic ring and an inner metallic disk. The connection provides durable coupling of a heat sink and a heat source.

  2. Reexamination of Basal Plane Thermal Conductivity of Suspended Graphene Samples Measured by Electro-Thermal Micro-Bridge Methods

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jo, Insun; Pettes, Michael; Lindsay, Lucas R; Ou, Eric; Weathers, Annie; Moore, Arden; Yao, Zhen; Shi, Li

    2015-01-01

    Thermal transport in suspended graphene samples has been measured in prior works and this work with the use of a suspended electro-thermal micro-bridge method. These measurement results are analyzed here to evaluate and eliminate the errors caused by the extrinsic thermal contact resistance. It is noted that the thermal resistance measured in a recent work increases linearly with the suspended length of the single-layer graphene samples synthesized by chemical vapor deposition (CVD), and that such a feature does not reveal the failure of Fourier s law despite the increase in the apparent thermal conductivity with length. The re-analyzed thermal conductivitymore » of a single-layer CVD graphene sample reaches about ( 1680 180 )Wm-1K-1 at room temperature, which is close to the highest value reported for highly oriented pyrolytic graphite. In comparison, the thermal conductivity values measured for two suspended exfoliated bi-layer graphene samples are about ( 880 60 ) and ( 730 60 ) Wm-1K-1 at room temperature, and approach that of the natural graphite source above room temperature. However, the low-temperature thermal conductivities of these suspended graphene samples are still considerably lower than the graphite values, with the peak thermal conductivities shifted to much higher temperatures. Analysis of the thermal conductivity data reveals that the low temperature behavior is dominated by phonon scattering by polymer residue instead of by the lateral boundary.« less

  3. Thermal conductivity of configurable two-dimensional carbon nanotube architecture and strain modulation

    SciTech Connect (OSTI)

    Zhan, H. F.; Bell, J. M.; Gu, Y. T., E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George St., Brisbane, Queensland 4000 (Australia); Zhang, G. [Institute of High Performance Computing, Agency for Science, Technology and Research, 1 Fusionopolis Way, Singapore 138632 (Singapore)

    2014-10-13

    We reported the thermal conductivity of the two-dimensional carbon nanotube (CNT)-based architecture, which can be constructed through welding of single-wall CNTs by electron beam. Using large-scale nonequilibrium molecular dynamics simulations, the thermal conductivity is found to vary with different junction types due to their different phonon scatterings at the junction. The strong length and strain dependence of the thermal conductivity suggests an effective avenue to tune the thermal transport properties of the CNT-based architecture, benefiting the design of nanoscale thermal rectifiers or phonon engineering.

  4. Thermally-assisted-occupation density functional theory with generalized-gradient approximations

    SciTech Connect (OSTI)

    Chai, Jeng-Da

    2014-05-14

    We extend the recently proposed thermally-assisted-occupation density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] to generalized-gradient approximation (GGA) exchange-correlation density functionals. Relative to our previous TAO-LDA (i.e., the local density approximation to TAO-DFT), the resulting TAO-GGAs are significantly superior for a wide range of applications, such as thermochemistry, kinetics, and reaction energies. For noncovalent interactions, TAO-GGAs with empirical dispersion corrections are shown to yield excellent performance. Due to their computational efficiency for systems with strong static correlation effects, TAO-LDA and TAO-GGAs are applied to study the electronic properties (e.g., the singlet-triplet energy gaps, vertical ionization potentials, vertical electron affinities, fundamental gaps, and symmetrized von Neumann entropy) of acenes with different number of linearly fused benzene rings (up to 100), which is very challenging for conventional electronic structure methods. The ground states of acenes are shown to be singlets for all the chain lengths studied here. With the increase of acene length, the singlet-triplet energy gaps, vertical ionization potentials, and fundamental gaps decrease monotonically, while the vertical electron affinities and symmetrized von Neumann entropy (i.e., a measure of polyradical character) increase monotonically.

  5. Measurement of thermal conductivity in proton irradiated silicon...

    Office of Scientific and Technical Information (OSTI)

    we perform our measurement on uncoated samples. This provides greater sensitivity to the change in conductivity of the thin damaged layer. Using sample temperature as a parameter ...

  6. Tuning Interfacial Thermal Conductance of Graphene Embedded in Soft Materials by Vacancy Defects

    SciTech Connect (OSTI)

    Liu, Ying; Hu, Chongze; Huang, Jingsong; Sumpter, Bobby G; Qiao, Rui

    2015-01-01

    Nanocomposites based on graphene dispersed in matrices of soft materials are promising thermal management materials. Their effective thermal conductivity depends on both the thermal conductivity of graphene and the conductance of the thermal transport across graphene-matrix interfaces. Here we report on molecular dynamics simulations of the thermal transport across the interfaces between defected graphene and soft materials in two different modes: in the across mode, heat enters graphene from one side of its basal plane and leaves through the other side; in the non-across mode, heat enters or leaves a graphene simultaneously from both sides of its basal plane. We show that, as the density of vacancy defects in graphene increases from 0 to 8%, the conductance of the interfacial thermal transport in the across mode increases from 160.4 16 to 207.8 11 MW/m2K, while that in the non-across mode increases from 7.2 0.1 to 17.8 0.6 MW/m2K. The molecular mechanisms for these variations of thermal conductance are clarified by using the phonon density of states and structural characteristics of defected graphenes. On the basis of these results and effective medium theory, we show that it is possible to enhance the effective thermal conductivity of thermal nanocomposites by tuning the density of vacancy defects in graphene despite the fact that graphene s thermal conductivity always decreases as vacancy defects are introduced.

  7. Thermal Gradient Holes At Twenty-Nine Palms Area (Page, Et Al...

    Open Energy Info (EERE)

    gradient holes for the GPO. Samples taken from each hole were similar in nature; mixtures of sand and conglomerates with the occasional granite sections were...

  8. Experimental and numerical study of the effective thermal conductivity...

    Office of Scientific and Technical Information (OSTI)

    The small gaps between the two material faces makes up the ... accurately for macro size contacts between two metals, ... The bulk conductivity of the sample is measured and Rc is ...

  9. Experimental investigation of the thermal conductivity of porous adsorbents. Master's thesis

    SciTech Connect (OSTI)

    Secary, J.J.

    1989-01-01

    The thermal conductivities of Praseodymium-Cerium-Oxide (PCO) and Saran Carbon have been experimentally investigated using a steady-state heat transfer technique. The investigated substances are used as adsorbents in adsorption compressors being developed for spaceborne refrigeration applications. The objectives of the investigation were to determine the thermal conductivities and establish their temperature dependency. Data were collected for the PCO over a temperature range of 300 C to 600 C, and O (zero) C to 200 C for the Saran Carbon. The thermal conductivities were found to have a strong temperature dependency. In particular, the results for the PCO showed a temperature dependency indicative of some thermal radiation effects.

  10. Thermal conductivity changes upon neutron transmutation of {sup 10}B doped diamond

    SciTech Connect (OSTI)

    Jagannadham, K., E-mail: jag-kasichainula@ncsu.edu [Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Verghese, K. [Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Butler, J. E. [Code 6174, Naval research Laboratory, Washington, District of Columbia 20375 (United States)

    2014-08-28

    {sup 10}B doped p-type diamond samples were subjected to neutron transmutation reaction using thermal neutron flux of 0.9 10{sup 13} cm{sup ?2} s{sup ?1} and fast neutron flux of 0.09 10{sup 13} cm{sup ?2} s{sup ?1}. Another sample of epilayer grown on type IIa (110) single crystal diamond substrate was subjected to equal thermal and fast neutron flux of 10{sup 14}?cm{sup ?2} s{sup ?1}. The defects in the diamond samples were previously characterized by different methods. In the present work, thermal conductivity of these diamond samples was determined at room temperature by transient thermoreflectance method. The thermal conductivity change in the samples as a function of neutron fluence is explained by the phonon scattering from the point defects and disordered regions. The thermal conductivity of the diamond samples decreased more rapidly initially and less rapidly for larger neutron fluence. In addition, the thermal conductivity in type IIb diamond decreased less rapidly with thermal neutron fluence compared to the decrease in type IIa diamond subjected to fast neutron fluence. It is concluded that the rate of production of defects during transmutation reaction is slower when thermal neutrons are used. The thermal conductivity of epilayer of diamond subjected to high thermal and fast neutron fluence is associated with the covalent carbon network in the composite structure consisting of disordered carbon and sp{sup 2} bonded nanocrystalline regions.

  11. Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites

    SciTech Connect (OSTI)

    Liu, Ying; Huang, Jingsong; Yang, Bao; Sumpter, Bobby G; Qiao, Rui

    2014-01-01

    The thermal conductance of graphene-matrix interfaces plays a key role in controlling the thermal transport properties of graphene-based nanocomposites. Using classical molecular dynamics simulations, we found that the interfacial thermal conductance depends strongly on the mode of heat transfer at the graphene-matrix interfaces: if heat enters graphene from one side of its basal plane and immediately leaves the graphene through the other side, the corresponding interfacial thermal conductance, G(across), is large; if heat enters graphene from both sides of its basal plane and leaves the graphene at a position far away on its basal plane, the corresponding interfacial thermal conductance, G(non-across), is small. For a single-layer graphene immersed in liquid octane, G(across) is ~150 MW/m2K while Gnon-across is ~5 MW/m2K. G(across) decreases with increasing multi-layer graphene thickness (i.e., number of layers in graphene) and approaches an asymptotic value of 100 MW/m2K for 7-layer graphenes. G(non-across) increases only marginally as the graphene sheet thickness increases. Such a duality of the interface thermal conductance for different probing methods and its dependence on graphene sheet thickness can be traced ultimately to the unique physical and chemical structure of graphene materials. The ramifications of these results in areas such as experimental measurement of thermal conductivity of graphene and the design of graphene-based thermal nanocomposites are discussed.

  12. Thermal desorption treatability test conducted with VAC*TRAX Unit

    SciTech Connect (OSTI)

    1996-01-01

    In 1992, Congress passed the Federal Facilities Compliance Act, requiring the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with Resource Conservation and Recovery Act (RCRA) treatment standards. In response to the need for mixed-waste treatment capacity, where off-site commercial treatment facilities do not exist or cannot be used, the DOE Albuquerque Operations Office (DOE-AL) organized a Treatment Selection Team to match mixed waste with treatment options and develop a strategy for treatment of mixed waste. DOE-AL manages nine sites with mixed-waste inventories. The Treatment Selection Team determined a need to develop mobile treatment units (MTUs) to treat waste at the sites where the wastes are generated. Treatment processes used for mixed wastes must remove the hazardous component (i.e., meet RCRA treatment standards) and contain the radioactive component in a form that will protect the worker, public, and environment. On the basis of the recommendations of the Treatment Selection Team, DOE-AL assigned projects to the sites to bring mixed-waste treatment capacity on-line. The three technologies assigned to the DOE Grand Junction Projects Office (DOE-GJPO) include thermal desorption (TD), evaporative oxidation, and waste water evaporation.

  13. Thermal flux limited electron Kapitza conductance in copper-niobium multilayers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cheaito, Ramez; Hattar, Khalid Mikhiel; Gaskins, John T.; Yadav, Ajay K.; Duda, John C.; Beechem, III, Thomas Edwin; Ihlefeld, Jon; Piekos, Edward S.; Baldwin, Jon K.; Misra, Amit; et al

    2015-03-05

    The interplay between the contributions of electron thermal flux and interface scattering to the Kapitza conductance across metal-metal interfaces through measurements of thermal conductivity of copper-niobium multilayers was studied. Thermal conductivities of copper-niobium multilayer films of period thicknesses ranging from 5.4 to 96.2 nm and sample thicknesses ranging from 962 to 2677 nm are measured by time-domain thermoreflectance over a range of temperatures from 78 to 500 K. The Kapitza conductances between the Cu and Nb interfaces in multilayer films are determined from the thermal conductivities using a series resistor model and are in good agreement with the electron diffusemore » mismatch model. The results for the thermal boundary conductance between Cu and Nb are compared to literature values for the thermal boundary conductance across Al-Cu and Pd-Ir interfaces, and demonstrate that the interface conductance in metallic systems is dictated by the temperature derivative of the electron energy flux in the metallic layers, rather than electron mean free path or scattering processes at the interface.« less

  14. Effect of point defects on the thermal conductivity of UO2: molecular dynamics simulations

    SciTech Connect (OSTI)

    Liu, Xiang-Yang; Stanek, Christopher Richard; Andersson, Anders David Ragnar

    2015-07-21

    The thermal conductivity of uranium dioxide (UO2) fuel is an important materials property that affects fuel performance since it is a key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. [1] The thermal conductivity of UO2 nuclear fuel is also affected by fission gas, fission products, defects, and microstructural features such as grain boundaries. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of irradiation induced point defects on the thermal conductivity of UO2, as a function of defect concentrations, for a range of temperatures, 300 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel [2].

  15. Thermal Conductivity Measurements of Bulk Thermoelectric Materials (Prop. 2004-067)

    SciTech Connect (OSTI)

    Wang, Hsin; Porter, Wallace D; Sharp, J

    2006-01-01

    Thermal conductivity is an important material property of the bulk thermoelectrics. To improve ZT a reduced thermal conductivity is always desired. However, there is no standard material for thermoelectrics and the test results, even on the same material, often show significant scatter. The scatter in thermal conductivity made reported ZT values uncertain and sometime unrepeatable. One of the reasons for the uncertainty is due to the microstructure differences resulting from sintering, heat treatment and other processing parameters. They selected commonly used bulk thermoelectric materials and conducted thermal conductivity measurements using the laser flash diffusivity and differential scanning calorimeter (DSC) systems. Thermal conductivity was measured as a function of temperature of temperature from room temperature to 500 K and back to room temperature. The effect of thermal cycling on the bulk thermoelectric was studied. Comnbined with measurements on electrical resistivity and Seebeck coefficient, they show the use of a ZT map in selecting thermoelectrics. The commercial bulk material showed very good consistency and reliability compared to other bulk materials. The goal is to develop a thermal transport properties database for the bulk thermoelectrics and make the information available to the research community and industry.

  16. Enhancing through thickness thermal conductivity of ultra-thin composite laminates. Final report

    SciTech Connect (OSTI)

    Ramani, K.; Vaidyanathan, A.

    1994-12-31

    The materials used in electronic applications have specific requirements for stiffness, thermal conductivity, and electromagnetic shielding making the choice of materials used very important. Electronic components are very sensitive to heat, hence the heat dissipation or cooling of the various components is necessary to prevent failure. Thus, any material used in the electronic industry must have a high thermal conductivity in addition to a specified thermal expansion, stiffness and strength properties. The purpose of this project was to design and manufacture composite panels which would conduct heat from an electronic chip attached to the top surface to a cooling liquid flowing at its lower surface. To maximize the heat conducted from the chip to the cooling liquid, the composite must have a high through thickness thermal conductivity. Further, design restrictions on the thickness of the composite panel had to be taken into account. It was found that the presence of excess resin adversely affects the conductivity of a woven fabric composite due to which the through thickness conductivity of the 400 {micro}m thick panel was better than the 500 {micro}m thick panel. The through thickness conductivity of the panel with short fibers alone was better than that of the woven cloth panel. The finite element model developed for a priori prediction of the through thickness thermal conductivity of the composite panels is a very powerful tool that can save enormous prototyping times an associates coats.

  17. Thermally conductive alumina/organic composites for photovoltaic concentrator cell isolation

    SciTech Connect (OSTI)

    Beavis, L.C.; Panitz, J.K.G.; Sharp, D.J.

    1988-01-01

    Electrophoretically deposited styrene-acrylate films were studied. These yield marginally useful thermal conductivities of 0.1--0.2 watts/meter-Kelvin, but have useful dielectric strengths over 2500 volts for 40 micrometer thick coatings. Thin, 25 micrometer, coatings of anodically grown Al/sub 2/O/sub 3/ films were also investigated. These films have thermal conductivities of approximately 6--8 watts/meter-Kelvin. Although these Al/sub 2/O/sub 3/ films have greater thermal conductivity than the polymer films, they exhibit porosity which typically limits their dielectric strength to less than 1000 volts. In the current study we have determined that styrene-acrylate can be electrophoretically deposited in porous anodic aluminum oxide films to form an alumina-organic composite with improved electrical breakdown strengths as well as higher thermal conductivity than styrene-acrylate films. 7 refs., 2 tabs.

  18. Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube

    DOE Patents [OSTI]

    Zhang, Zhiqiang (Lexington, KY); Lockwood, Frances E. (Georgetown, KY)

    2008-03-25

    A fluid media such as oil or water, and a selected effective amount of carbon nanomaterials necessary to enhance the thermal conductivity of the fluid. One of the preferred carbon nanomaterials is a high thermal conductivity graphite, exceeding that of the neat fluid to be dispersed therein in thermal conductivity, and ground, milled, or naturally prepared with mean particle size less than 500 nm, and preferably less than 200 nm, and most preferably less than 100 nm. The graphite is dispersed in the fluid by one or more of various methods, including ultrasonication, milling, and chemical dispersion. Carbon nanotubes with graphitic structure is another preferred source of carbon nanomaterial, although other carbon nanomaterials are acceptable. To confer long term stability, the use of one or more chemical dispersants is preferred. The thermal conductivity enhancement, compared to the fluid without carbon nanomaterial, is proportional to the amount of carbon nanomaterials (carbon nanotubes and/or graphite) added.

  19. Basal-plane thermal conductivity of few-layer molybdenum disulfide

    SciTech Connect (OSTI)

    Jo, Insun; Ou, Eric; Shi, Li; Pettes, Michael Thompson; Wu, Wei

    2014-05-19

    We report the in-plane thermal conductivity of suspended exfoliated few-layer molybdenum disulfide (MoS{sub 2}) samples that were measured by suspended micro-devices with integrated resistance thermometers. The obtained room-temperature thermal conductivity values are (4450) and (4852) W m{sup ?1} K{sup ?1} for two samples that are 4 and 7 layers thick, respectively. For both samples, the peak thermal conductivity occurs at a temperature close to 120?K, above which the thermal conductivity is dominated by intrinsic phonon-phonon scattering although phonon scattering by surface disorders can still play an important role in these samples especially at low temperatures.

  20. Development of a Test Technique to Determine the Thermal Conductivity of

    Office of Scientific and Technical Information (OSTI)

    Large Refractory Ceramic Test Specimens (Journal Article) | SciTech Connect Journal Article: Development of a Test Technique to Determine the Thermal Conductivity of Large Refractory Ceramic Test Specimens Citation Details In-Document Search Title: Development of a Test Technique to Determine the Thermal Conductivity of Large Refractory Ceramic Test Specimens A method has been developed to utilize the High Intensity Infrared lamp located at Oak Ridge National Laboratory for the measurement

  1. Thermal Conductivity in Nanoporous Gold Films during Electron-Phonon Nonequilibrium

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hopkins, Patrick E.; Norris, Pamela M.; Phinney, Leslie M.; Policastro, Steven A.; Kelly, Robert G.

    2008-01-01

    The reduction of nanodevices has given recent attention to nanoporous materials due to their structure and geometry. However, the thermophysical properties of these materials are relatively unknown. In this article, an expression for thermal conductivity of nanoporous structures is derived based on the assumption that the finite size of the ligaments leads to electron-ligament wall scattering. This expression is then used to analyze the thermal conductivity of nanoporous structures in the event of electron-phonon nonequilibrium.

  2. Thermal conductivity prediction of magnetic composite sheet for near-field electromagnetic absorption

    SciTech Connect (OSTI)

    Lee, Joonsik; Nam, Baekil; Ko, Frank K.; Kim, Ki Hyeon

    2015-05-07

    The magnetic composite sheets were designed by using core-shell structured magnetic fillers instead of uncoated magnetic fillers to resolve concurrently the electromagnetic interference and thermal radiation problems. To predict the thermal conductivity of composite sheet, we calculated the thermal conductivity of the uncoated magnetic fillers and core-shell structured fillers. And then, the thermal conductivity of the magnetic composites sheet filled with core-shell structured magnetic fillers was calculated and compared with that of the uncoated magnetic fillers filled in composite sheet. The magnetic core and shell material are employed the typical Fe-Al-Si flake (60??m??60??m??1??m) and 250?nm-thick AlN with high thermal conductivity, respectively. The longitudinal thermal conductivity of the core-shell structured magnetic composite sheet (2.45?W/mK) enhanced about 33.4% in comparison with that of uncoated magnetic fillers (1.83?W/mK) for the 50 vol. % magnetic filler in polymer matrix.

  3. Nanoscale size dependence parameters on lattice thermal conductivity of Wurtzite GaN nanowires

    SciTech Connect (OSTI)

    Mamand, S.M.; Omar, M.S.; Muhammad, A.J.

    2012-05-15

    Graphical abstract: Temperature dependence of calculated lattice thermal conductivity of Wurtzite GaN nanowires. Highlights: Black-Right-Pointing-Pointer A modified Callaway model is used to calculate lattice thermal conductivity of Wurtzite GaN nanowires. Black-Right-Pointing-Pointer A direct method is used to calculate phonon group velocity for these nanowires. Black-Right-Pointing-Pointer 3-Gruneisen parameter, surface roughness, and dislocations are successfully investigated. Black-Right-Pointing-Pointer Dislocation densities are decreases with the decrease of wires diameter. -- Abstract: A detailed calculation of lattice thermal conductivity of freestanding Wurtzite GaN nanowires with diameter ranging from 97 to 160 nm in the temperature range 2-300 K, was performed using a modified Callaway model. Both longitudinal and transverse modes are taken into account explicitly in the model. A method is used to calculate the Debye and phonon group velocities for different nanowire diameters from their related melting points. Effect of Gruneisen parameter, surface roughness, and dislocations as structure dependent parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the experimentally measured curves. It was observed that Gruneisen parameter will decrease with decreasing nanowire diameters. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Phonon confinement and size effects as well as the role of dislocation in limiting thermal conductivity are investigated. At high temperatures and for dislocation densities greater than 10{sup 14} m{sup -2} the lattice thermal conductivity would be limited by dislocation density, but for dislocation densities less than 10{sup 14} m{sup -2}, lattice thermal conductivity would be independent of that.

  4. Composite material having high thermal conductivity and process for fabricating same

    DOE Patents [OSTI]

    Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

    1998-01-01

    A process for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost.

  5. Composite material having high thermal conductivity and process for fabricating same

    DOE Patents [OSTI]

    Colella, N.J.; Davidson, H.L.; Kerns, J.A.; Makowiecki, D.M.

    1998-07-21

    A process is disclosed for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost. 7 figs.

  6. Modeling the Influence of Interaction Layer Formation on Thermal Conductivity of UMo Dispersion Fuel

    SciTech Connect (OSTI)

    Burkes, Douglas; Casella, Andrew M.; Huber, Tanja K.

    2015-01-01

    The Global Threat Reduction Initiative Program continues to develop existing and new plate- and rod-type research and test reactor fuels with maximum attainable uranium loadings capable of potentially converting a number of the worlds remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of an even higher density fuel type consisting of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel plate and can be influenced by interaction layer formation between the fuel and matrix, porosity that forms during fabrication of the fuel plates, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation and conductivity, fuel particle size, and volume fraction of fuel dispersed in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be important in determining the overall conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the fuel particle distribution by minimizing interaction layer formation and preserving the higher thermal conductivity matrix.

  7. Thermal conductivity measurements via time-domain thermoreflectance for the characterization of radiation induced damage

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cheaito, Ramez; Gorham, Caroline S.; Carnegie Mellon Univ., Pittsburgh, PA; Misra, Amit; Hattar, Khalid; Hopkins, Patrick E.

    2015-05-01

    The progressive build up of displacement damage and fission products inside different systems and components of a nuclear reactor can lead to significant defect formation, degradation, and damage of the constituent materials. This structural modification can highly influence the thermal transport mechanisms and various mechanical properties of solids. In this paper we demonstrate the use of time-domain thermoreflectance (TDTR), a non-destructive method capable of measuring the thermal transport in material systems from nano to bulk scales, to study the effect of radiation damage and the subsequent changes in the thermal properties of materials. We use TDTR to show that displacementmore » damage from ion irradiation can significantly reduce the thermal conductivity of Optimized ZIRLO, a material used as fuel cladding in several current nuclear reactors. We find that the thermal conductivity of copper-niobium nanostructured multilayers does not change with helium ion irradiation doses of up to 1015 cm-2 and ion energy of 200 keV suggesting that these structures can be used and radiation tolerant materials in nuclear reactors. We compare the effect of ion doses and ion beam energies on the measured thermal conductivity of bulk silicon. Results demonstrate that TDTR thermal measurements can be used to quantify depth dependent damage.« less

  8. Thermal conductivity measurements via time-domain thermoreflectance for the characterization of radiation induced damage

    SciTech Connect (OSTI)

    Cheaito, Ramez; Gorham, Caroline S.; Misra, Amit; Hattar, Khalid; Hopkins, Patrick E.

    2015-05-01

    The progressive build up of displacement damage and fission products inside different systems and components of a nuclear reactor can lead to significant defect formation, degradation, and damage of the constituent materials. This structural modification can highly influence the thermal transport mechanisms and various mechanical properties of solids. In this paper we demonstrate the use of time-domain thermoreflectance (TDTR), a non-destructive method capable of measuring the thermal transport in material systems from nano to bulk scales, to study the effect of radiation damage and the subsequent changes in the thermal properties of materials. We use TDTR to show that displacement damage from ion irradiation can significantly reduce the thermal conductivity of Optimized ZIRLO, a material used as fuel cladding in several current nuclear reactors. We find that the thermal conductivity of copper-niobium nanostructured multilayers does not change with helium ion irradiation doses of up to 1015 cm-2 and ion energy of 200 keV suggesting that these structures can be used and radiation tolerant materials in nuclear reactors. We compare the effect of ion doses and ion beam energies on the measured thermal conductivity of bulk silicon. Results demonstrate that TDTR thermal measurements can be used to quantify depth dependent damage.

  9. Approaching the Minimum Thermal Conductivity in Rhenium-Substituted Higher Manganese Silicides

    SciTech Connect (OSTI)

    Chen, Xi [University of Texas at Austin] [University of Texas at Austin; Girard, S. N. [University of Wisconsin, Madison] [University of Wisconsin, Madison; Meng, F. [University of Wisconsin, Madison] [University of Wisconsin, Madison; Lara-Curzio, Edgar [ORNL] [ORNL; Jin, S [University of Wisconsin, Madison] [University of Wisconsin, Madison; Goodenough, J. B. [University of Texas at Austin] [University of Texas at Austin; Zhou, J. S. [University of Texas at Austin] [University of Texas at Austin; Shi, L [University of Texas at Austin] [University of Texas at Austin

    2014-01-01

    Higher manganese silicides (HMS) made of earth-abundant and non-toxic elements are regarded as promising p-type thermoelectric materials because their complex crystal structure results in low lattice thermal conductivity. It is shown here that the already low thermal conductivity of HMS can be reduced further to approach the minimum thermal conductivity via partial substitu- tion of Mn with heavier rhenium (Re) to increase point defect scattering. The solubility limit of Re in the obtained RexMn1 xSi1.8 is determined to be about x = 0.18. Elemental inhomogeneity and the formation of ReSi1.75 inclusions with 50 200 nm size are found within the HMS matrix. It is found that the power factor does not change markedly at low Re content of x 0.04 before it drops considerably at higher Re contents. Compared to pure HMS, the reduced lattice thermal conductivity in RexMn1 xSi1.8 results in a 25% increase of the peak figure of merit ZT to reach 0.57 0.08 at 800 K for x = 0.04. The suppressed thermal conductivity in the pure RexMn1 xSi1.8 can enable further investigations of the ZT limit of this system by exploring different impurity doping strategies to optimize the carrier concentration and power factor.

  10. Thermal conductivity of high performance carbon nanotube yarn-like fibers

    SciTech Connect (OSTI)

    Mayhew, Eric; Prakash, Vikas

    2014-05-07

    In the present paper, we present results of thermal conductivity measurements in free standing carbon nanotube (CNT) yarn-like fibers. The measurements are made using a T-type experimental configuration utilizing a Wollaston-wire hot probe inside a scanning electron microscope. In this technique, a suspended platinum wire is used both as a heater and a thermal sensor. A low frequency alternating current source is used to heat the probe wire while the third harmonic voltage across the wire is measured by a lock-in amplifier. The conductivity is deduced from an analytical model that relates the drop in the spatially averaged temperature of the wire to that of the sample. The average thermal conductivity of the neat CNT fibers and the CNT polymer composite fibers is found to be 448?W/m-K and 225?W/m-K, respectively. These values for conductivity are amongst the highest measured for CNT yarn-like fibers fabricated using a dry spinning process from vertically aligned CNT arrays. The enhancement in thermal conductivity is understood to be due to an increase in the CNT fiber elastic stiffness during the draw and twist operations, lower CNT thermal contact resistance due to increase in CNT contact area, and better alignment of the CNT fibrils along the length of the fiber.

  11. Thermal Properties Capability Development Workshop Summary to Support the Implementation Plan for PIE Thermal Conductivity Measurements

    SciTech Connect (OSTI)

    Braase, Lori; Papesch, Cynthia; Hurley, David

    2015-04-01

    The Department of Energy (DOE)-Office of Nuclear Energy (NE), Idaho National Laboratory (INL), and associated nuclear fuels programs have invested heavily over the years in infrastructure and capability development. With the current domestic and international need to develop Accident Tolerant Fuels (ATF), increasing importance is being placed on understanding fuel performance in irradiated conditions and on the need to model and validate that performance to reduce uncertainty and licensing timeframes. INLs Thermal Properties Capability Development Workshop was organized to identify the capability needed by the various nuclear programs and list the opportunities to meet those needs. In addition, by the end of fiscal year 2015, the decision will be made on the initial thermal properties instruments to populate the shielded cell in the Irradiated Materials Characterization Laboratory (IMCL).

  12. Calculated transport properties of CdO: thermal conductivity and thermoelectric power factor

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lindsay, Lucas R.; Parker, David S.

    2015-10-01

    We present first principles calculations of the thermal and electronic transport properties of the oxide semiconductor CdO. In particular, we find from theory that the accepted thermal conductivity κ value of 0.7 Wm-1K-1 is approximately one order of magnitude too small; our calculations of κ of CdO are in good agreement with recent measurements. We also find that alloying of MgO with CdO is an effective means to reduce the lattice contribution to κ, despite MgO having a much larger thermal conductivity. We further consider the electronic structure of CdO in relation to thermoelectric performance, finding that large thermoelectric powermore » factors may occur if the material can be heavily doped p-type. This work develops insight into the nature of thermal and electronic transport in an important oxide semiconductor.« less

  13. Calculated transport properties of CdO: thermal conductivity and thermoelectric power factor

    SciTech Connect (OSTI)

    Lindsay, Lucas R.; Parker, David S.

    2015-10-01

    We present first principles calculations of the thermal and electronic transport properties of the oxide semiconductor CdO. In particular, we find from theory that the accepted thermal conductivity ? value of 0.7 Wm-1K-1 is approximately one order of magnitude too small; our calculations of ? of CdO are in good agreement with recent measurements. We also find that alloying of MgO with CdO is an effective means to reduce the lattice contribution to ?, despite MgO having a much larger thermal conductivity. We further consider the electronic structure of CdO in relation to thermoelectric performance, finding that large thermoelectric power factors may occur if the material can be heavily doped p-type. This work develops insight into the nature of thermal and electronic transport in an important oxide semiconductor.

  14. Esimation of field-scale thermal conductivities of unsaturatedrocks from in-situ temperature data

    SciTech Connect (OSTI)

    Mukhopadhyay, Sumit; Tsang, Yvonne W.; Birkholzer, Jens T.

    2006-06-26

    A general approach is presented here which allows estimationof field-scale thermal properties of unsaturated rock using temperaturedata collected from in situ heater tests. The approach developed here isused to determine the thermal conductivities of the unsaturated host rockof the Drift Scale Test (DST) at Yucca Mountain, Nevada. The DST wasdesigned to obtain thermal, hydrological, mechanical, and chemical (THMC)data in the unsaturated fractured rock of Yucca Mountain. Sophisticatednumerical models have been developed to analyze these THMC data. However,though the objective of those models was to analyze "field-scale" (of theorder of tens-of-meters) THMC data, thermal conductivities measured from"laboratory-scale" core samples have been used as input parameters.While, in the absence of a better alternative, using laboratory-scalethermal conductivity values in field-scale models can be justified, suchapplications introduce uncertainties in the outcome of the models. Thetemperature data collected from the DST provides a unique opportunity toresolve some of these uncertainties. These temperature data can be usedto estimate the thermal conductivity of the DST host rock and, given thelarge volume of rock affected by heating at the DST, such an estimatewill be a more reliable effective thermal conductivity value for fieldscale application. In this paper, thus, temperature data from the DST areused to develop an estimate of the field-scale thermal conductivityvalues of the unsaturated host rock of the DST. An analytical solution isdeveloped for the temperature rise in the host rock of the DST; and usinga nonlinear fitting routine, a best-fit estimate of field-scale thermalconductivity for the DST host rock is obtained. Temperature data from theDST show evidence of two distinct thermal regimes: a zone below boiling(wet) and a zone above boiling (dry). Estimates of thermal conductivityfor both the wet and dry zones are obtained in this paper. Sensitivity ofthese estimates to the input heating power of the DST is alsoinvestigated in this paper. These estimated thermal conductivity valuesare compared with core measurements and those estimated fromgeostatistical simulations. Note that the approach presented here isapplicable to other host rock and heater test settings, provided suitablemodifications are made in the analytical solution to account fordifferences in test geometry.

  15. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect (OSTI)

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600?C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600?C. TiN film deposited at 600?C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600?C on Si(111) wafer but the film deposited at 500?C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600?C. Nitride film of tungsten deposited at 600?C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500?C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600?C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

  16. Pump-probe measurements of the thermal conductivity tensor for materials lacking in-plane symmetry

    SciTech Connect (OSTI)

    Feser, Joseph P. [Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Liu, Jun; Cahill, David G. [Department of Materials Science and Engineering, and Frederick-Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)

    2014-10-15

    We previously demonstrated an extension of time-domain thermoreflectance (TDTR) which utilizes offset pump and probe laser locations to measure in-plane thermal transport properties of multilayers. However, the technique was limited to systems of transversely isotropic materials studied using axisymmetric laser intensities. Here, we extend the mathematics so that data reduction can be performed on non-transversely isotropic systems. An analytic solution of the diffusion equation for an N-layer system is given, where each layer has a homogenous but otherwise arbitrary thermal conductivity tensor and the illuminating spots have arbitrary intensity profiles. As a demonstration, we use both TDTR and time-resolved magneto-optic Kerr effect measurements to obtain thermal conductivity tensor elements of <110> ?-SiO{sub 2}. We show that the out-of-phase beam offset sweep has full-width half-maxima that contains nearly independent sensitivity to the in-plane thermal conductivity corresponding to the scanning direction. Also, we demonstrate a Nb-V alloy as a low thermal conductivity TDTR transducer layer that helps improve the accuracy of in-plane measurements.

  17. A robust and well shielded thermal conductivity device for low temperature measurements

    SciTech Connect (OSTI)

    Toews, W. H.; Hill, R. W.

    2014-04-15

    We present a compact mechanically robust thermal conductivity measurement apparatus for measurements at low temperatures (<1 K) and high magnetic fields on small high-purity single crystal samples. A high-conductivity copper box is used to enclose the sample and all the components. The box provides protection for the thermometers, heater, and most importantly the sample increasing the portability of the mount. In addition to physical protection, the copper box is also effective at shielding radio frequency electromagnetic interference and thermal radiation, which is essential for low temperature measurements. A printed circuit board in conjunction with a braided ribbon cable is used to organize the delicate wiring and provide mechanical robustness.

  18. Thermal conductance measurements of bolted copper joints for SuperCDMS

    SciTech Connect (OSTI)

    Schmitt, R.; Tatkowski, Greg; Ruschman, M.; Golwala, S. R.; Kellaris, N.; Daal, M.; Hall, Jeter C.; Hoppe, Eric W.

    2015-09-01

    Joint thermal conductance testing has been undertaken for bolted copper to copper connections from 60 mK to 26 K. This testing was performed to validate an initial design basis for the SuperCDMS experiment, where a dilution refrigerator will be coupled to a cryostat via multiple bolted connections. Copper used during testing was either gold plated or passivated with citric acid to prevent surface oxidation. Results obtained are well fit by a power law regression of joint thermal conductance to temperature and match well with data collected during a literature review.

  19. MESO-SCALE MODELING OF THE INFLUENCE OF INTERGRANULAR GAS BUBBLES ON EFFECTIVE THERMAL CONDUCTIVITY

    SciTech Connect (OSTI)

    Paul C. Millett; Michael Tonks

    2011-06-01

    Using a mesoscale modeling approach, we have investigated how intergranular fission gas bubbles, as observed in high-burnup nuclear fuel, modify the effective thermal conductivity in a polycrystalline material. The calculations reveal that intergranular porosity has a significantly higher resistance to heat transfer compared to randomly-distributed porosity. A model is developed to describe this conductivity reduction that considers an effective grain boundary Kapitza resistance as a function of the fractional coverage of grain boundaries by bubbles.

  20. Rapid processing of carbon-carbon composites by forced flow-thermal gradient chemical vapor infiltration (FCVI)

    SciTech Connect (OSTI)

    Vaidyaraman, S.; Lackey, W.J.; Agrawal, P.K.; Freeman, G.B.; Langman, M.D.

    1995-10-01

    Carbon fiber-carbon matrix composites were fabricated using the forced flow-thermal gradient chemical vapor infiltration (FCVI) process. Preforms were prepared by stacking 40 layers of plain weave carbon cloth in a graphite holder. The preforms were infiltrated using propylene, propane, and methane. The present work showed that the FCVI process is well suited for fabricating carbon-carbon composites; without optimization of the process, the authors have achieved uniform and thorough densification. Composites with porosities as low as 7% were fabricated in 8--12 h. The highest deposition rate obtained in the present study was {approximately}3 {micro}m/h which is more than an order of magnitude faster than the typical value of 0.1--0.25 {micro}m/h for the isothermal process. It was also found that the use of propylene and propane as reagents resulted in faster infiltration compared to methane.

  1. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    SciTech Connect (OSTI)

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; Lu, Xi; Riedo, Elisa; Meriles, Carlos A.

    2015-11-20

    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps. The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems.

  2. Imaging thermal conductivity with nanoscale resolution using a scanning spin probe

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Laraoui, Abdelghani; Aycock-Rizzo, Halley; Gao, Yang; Lu, Xi; Riedo, Elisa; Meriles, Carlos A.

    2015-11-20

    The ability to probe nanoscale heat flow in a material is often limited by lack of spatial resolution. Here, we use a diamond-nanocrystal-hosted nitrogen-vacancy centre attached to the apex of a silicon thermal tip as a local temperature sensor. We apply an electrical current to heat up the tip and rely on the nitrogen vacancy to monitor the thermal changes the tip experiences as it is brought into contact with surfaces of varying thermal conductivity. By combining atomic force and confocal microscopy, we image phantom microstructures with nanoscale resolution, and attain excellent agreement between the thermal conductivity and topographic maps.more » The small mass and high thermal conductivity of the diamond host make the time response of our technique short, which we demonstrate by monitoring the tip temperature upon application of a heat pulse. Our approach promises multiple applications, from the investigation of phonon dynamics in nanostructures to the characterization of heterogeneous phase transitions and chemical reactions in various solid-state systems.« less

  3. Asymptotic regimes for the electrical and thermal conductivities in dense plasmas

    SciTech Connect (OSTI)

    Faussurier, G. Blancard, C.

    2015-04-15

    We study the asymptotic regimes for the electrical and thermal conductivities in dense plasmas obtained by combining the Chester–Thellung–Kubo–Greenwood approach and the Kramers approximation [Faussurier et al., Phys. Plasmas 21, 092706 (2014)]. Non-degenerate and degenerate situations are considered. The Wiedemann–Franz law is obtained in the degenerate case.

  4. Measurement of the anisotropic thermal conductivity of molybdenum disulfide by the time-resolved magneto-optic Kerr effect

    SciTech Connect (OSTI)

    Liu, Jun Choi, Gyung-Min; Cahill, David G.

    2014-12-21

    We use pump-probe metrology based on the magneto-optic Kerr effect to measure the anisotropic thermal conductivity of (001)-oriented MoS{sub 2} crystals. A ?20?nm thick CoPt multilayer with perpendicular magnetization serves as the heater and thermometer in the experiment. The low thermal conductivity and small thickness of the CoPt transducer improve the sensitivity of the measurement to lateral heat flow in the MoS{sub 2} crystal. The thermal conductivity of MoS{sub 2} is highly anisotropic with basal-plane thermal conductivity varying between 85110 W?m{sup -1}?K{sup -1} as a function of laser spot size. The basal-plane thermal conductivity is a factor of ?50 larger than the c-axis thermal conductivity, 2.00.3?W?m{sup -1}?K{sup -1}.

  5. First-principles prediction of phononic thermal conductivity of silicene: A comparison with graphene

    SciTech Connect (OSTI)

    Gu, Xiaokun; Yang, Ronggui

    2015-01-14

    There has been great interest in two-dimensional materials, beyond graphene, for both fundamental sciences and technological applications. Silicene, a silicon counterpart of graphene, has been shown to possess some better electronic properties than graphene. However, its thermal transport properties have not been fully studied. In this paper, we apply the first-principles-based phonon Boltzmann transport equation to investigate the thermal conductivity of silicene as well as the phonon scattering mechanisms. Although both graphene and silicene are two-dimensional crystals with similar crystal structure, we find that phonon transport in silicene is quite different from that in graphene. The thermal conductivity of silicene shows a logarithmic increase with respect to the sample size due to the small scattering rates of acoustic in-plane phonon modes, while that of graphene is finite. Detailed analysis of phonon scattering channels shows that the linear dispersion of the acoustic out-of-plane (ZA) phonon modes, which is induced by the buckled structure, makes the long-wavelength longitudinal acoustic phonon modes in silicene not as efficiently scattered as that in graphene. Compared with graphene, where most of the heat is carried by the acoustic out-of-plane (ZA) phonon modes, the ZA phonon modes in silicene only have ?10% contribution to the total thermal conductivity, which can also be attributed to the buckled structure. This systematic comparison of phonon transport and thermal conductivity of silicene and graphene using the first-principle-based calculations shed some light on other two-dimensional materials, such as two-dimensional transition metal dichalcogenides.

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

    SciTech Connect (OSTI)

    Saygi, Salih

    2014-02-15

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

  7. Anomalous pressure dependence of thermal conductivities of large mass ratio compounds

    SciTech Connect (OSTI)

    Lindsay, Lucas R; Broido, David; Carrete, Jesus; Mingo, Natalio; Reinecke, Tom

    2015-01-01

    The lattice thermal conductivities ( ) of binary compound materials are examined as a function of hydrostatic pressure, P, using a first-principles approach. Compound materials with relatively small mass ratios, such as MgO, show an increase in with P, consistent with measurements. Conversely, compounds with large mass ratios (e.g., BSb, BAs, BeTe, BeSe) exhibit decreasing with increasing P, a behavior that cannot be understood using simple theories of . This anomalous P dependence of arises from the fundamentally different nature of the intrinsic scattering processes for heat-carrying acoustic phonons in large mass ratio compounds compared to those with small mass ratios. This work demonstrates the power of first principles methods for thermal properties and advances the understanding of thermal transport in non-metals.

  8. Anomalous pressure dependence of thermal conductivities of large mass ratio compounds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lindsay, Lucas R; Broido, David; Carrete, Jesus; Mingo, Natalio; Reinecke, Tom

    2015-01-01

    The lattice thermal conductivities ( ) of binary compound materials are examined as a function of hydrostatic pressure, P, using a first-principles approach. Compound materials with relatively small mass ratios, such as MgO, show an increase in with P, consistent with measurements. Conversely, compounds with large mass ratios (e.g., BSb, BAs, BeTe, BeSe) exhibit decreasing with increasing P, a behavior that cannot be understood using simple theories of . This anomalous P dependence of arises from the fundamentally different nature of the intrinsic scattering processes for heat-carrying acoustic phonons in large mass ratio compounds compared to those with small massmore » ratios. This work demonstrates the power of first principles methods for thermal properties and advances the understanding of thermal transport in non-metals.« less

  9. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOE Patents [OSTI]

    Christensen, Craig B. (Boulder, CO); Kutscher, Charles F. (Golden, CO); Gawlik, Keith M. (Boulder, CO)

    1997-01-01

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprising an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution.

  10. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOE Patents [OSTI]

    Christensen, C.B.; Kutscher, C.F.; Gawlik, K.M.

    1997-12-02

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprises an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution. 3 figs.

  11. Thermal conductivity studies of novel nanofluids based on metallic silver decorated mesoporous silica nanoparticles

    SciTech Connect (OSTI)

    Tadjarodi, Azadeh; Zabihi, Fatemeh

    2013-10-15

    Graphical abstract: - Highlights: Metallic silver was decorated in mSiO{sub 2} with grafted hemiaminal functional groups. Synthesized nanoparticles were used for preparation of glycerol based nanofluids. The effect of temperature, weight fraction of mSiO{sub 2} and concentration of silver nanoparticles on thermal conductivity of nanofluids was investigated. - Abstract: In the present study, the mesoporous structure of silica (mSiO{sub 2}) nanoparticles as well as hemiaminal grafted mSiO{sub 2} decorated by metallic silver (Ag/mSiO{sub 2}) has been used for the preparation of glycerol based nanofluids. Structural and morphological characterization of the synthesized products have been carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), UVvis spectroscopy, inductively coupled plasma (ICP) and N{sub 2} adsorptiondesorption isotherms. The thermal conductivity and viscosity of the nanofluids have been measured as a function of temperature for various weight fractions and silver concentrations of mSiO{sub 2} and Ag/mSiO{sub 2} nanoparticles, respectively. The results show that the thermal conductivity of the nanofluids increase up to 9.24% as the weight fraction of mSiO{sub 2} increases up to 4 wt%. Also, increasing the percent of the silver decorated mSiO{sub 2} (Ag/mSiO{sub 2}) up to 2.98% caused an enhancement in the thermal conductivity of the base fluid up to 10.95%. Furthermore, the results show that the nanofluids have Newtonian behavior in the tested temperature range for various concentrations of nanoparticles.

  12. High thermal conductivity lossy dielectric using co-densified multilayer configuration

    DOE Patents [OSTI]

    Tiegs, Terry N.; Kiggans, Jr., James O.

    2003-06-17

    Systems and methods are described for loss dielectrics. A method of manufacturing a lossy dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer and then densifying together. The systems and methods provide advantages because the lossy dielectrics are less costly and more environmentally friendly than the available alternatives.

  13. Atomistic study of porosity impact on phonon driven thermal conductivity: Application to uranium dioxide

    SciTech Connect (OSTI)

    Colbert, Mehdi; Ribeiro, Fabienne; Trglia, Guy

    2014-01-21

    We present here an analytical method, based on the kinetic theory, to determine the impact of defects such as cavities on the thermal conductivity of a solid. This approach, which explicitly takes into account the effects of internal pore surfaces, will be referred to as the Phonon Interface THermal cONductivity (PITHON) model. Once exposed in the general case, this method is then illustrated in the case of uranium dioxide. It appears that taking properly into account these interface effects significantly modifies the temperature and porosity dependence of thermal conductivity with respect to that issued from either micromechanical models or more recent approaches, in particular, for small cavity sizes. More precisely, it is found that if the mean free path appears to have a major effect in this system in the temperature and porosity distribution range of interest, the variation of the specific heat at the surface of the cavity is predicted to be essential at very low temperature and small sizes for sufficiently large porosity.

  14. ELECTRON THERMAL CONDUCTION AS A POSSIBLE PHYSICAL MECHANISM TO MAKE THE INNER HELIOSHEATH THINNER

    SciTech Connect (OSTI)

    Izmodenov, V. V. [Department of Mechanics and Mathematics, Lomonosov Moscow State University, 1 Leninskie gory, Moscow, 119991 (Russian Federation); Alexashov, D. B.; Ruderman, M. S., E-mail: izmod@ipmnet.ru [Space Research Institute (IKI) of Russian Academy of Sciences, 84/32 Profsoyuznaya Street, Moscow, 117997 (Russian Federation)

    2014-11-01

    We show that electron thermal conductivity may strongly affect the heliosheath plasma flow and the global pattern of the solar wind's interaction with the local interstellar medium. In particular, it leads to strong reduction of the inner heliosheath thickness, which makes it possible to explain (qualitatively) why Voyager 1 (V1) has crossed the heliopause at an unexpectedly small heliocentric distance of 122 AU. To estimate the effect of thermal conductivity, we consider a limiting case when thermal conduction is very effective. To do that, we assume the plasma flow in the entire heliosphere is nearly isothermal. Due to this effect, the heliospheric distance of the termination shock has increased by about 15 AU in the V1 direction compared with the adiabatic case with ? = 5/3. The heliospheric distance of the heliopause has decreased by about 27 AU. As a result, the thickness of the inner heliosheath in the model has decreased by about 42 AU and has become equal to 32 AU.

  15. Unusual Enhancement in Intrinsic Thermal Conductivity of Multilayer Graphene by Tensile Strains

    SciTech Connect (OSTI)

    Kuang, Youdi; Lindsay, Lucas R.; Huang, Baoling

    2015-01-01

    High basal plane thermal conductivity k of multi-layer graphene makes it promising for thermal management applications. Here we examine the effects of tensile strain on thermal transport in this system. Using a first principles Boltzmann-Peierls equation for phonon transport approach, we calculate the room-temperature in-plane lattice k of multi-layer graphene (up to four layers) and graphite under different isotropic tensile strains. The calculated in-plane k of graphite, finite mono-layer graphene and 3-layer graphene agree well with previous experiments. The dimensional transitions of the intrinsic k and the extent of the diffusive transport regime from mono-layer graphene to graphite are presented. We find a peak enhancement of intrinsic k for multi-layer graphene and graphite with increasing strain and the largest enhancement amplitude is about 40%. In contrast the calculated intrinsic k with tensile strain decreases for diamond and diverges for graphene, we show that the competition between the decreased mode heat capacities and the increased lifetimes of flexural phonons with increasing strain contribute to this k behavior. Similar k behavior is observed for 2-layer hexagonal boron nitride systems, suggesting that it is an inherent thermal transport property in multi-layer systems assembled of purely two dimensional atomic layers. This study provides insights into engineering k of multi-layer graphene and boron nitride by strain and into the nature of thermal transport in quasi-two-dimensional and highly anisotropic systems.

  16. Unusual Enhancement in Intrinsic Thermal Conductivity of Multilayer Graphene by Tensile Strains

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kuang, Youdi; Lindsay, Lucas R.; Huang, Baoling

    2015-01-01

    High basal plane thermal conductivity k of multi-layer graphene makes it promising for thermal management applications. Here we examine the effects of tensile strain on thermal transport in this system. Using a first principles Boltzmann-Peierls equation for phonon transport approach, we calculate the room-temperature in-plane lattice k of multi-layer graphene (up to four layers) and graphite under different isotropic tensile strains. The calculated in-plane k of graphite, finite mono-layer graphene and 3-layer graphene agree well with previous experiments. The dimensional transitions of the intrinsic k and the extent of the diffusive transport regime from mono-layer graphene to graphite are presented.moreWe find a peak enhancement of intrinsic k for multi-layer graphene and graphite with increasing strain and the largest enhancement amplitude is about 40%. In contrast the calculated intrinsic k with tensile strain decreases for diamond and diverges for graphene, we show that the competition between the decreased mode heat capacities and the increased lifetimes of flexural phonons with increasing strain contribute to this k behavior. Similar k behavior is observed for 2-layer hexagonal boron nitride systems, suggesting that it is an inherent thermal transport property in multi-layer systems assembled of purely two dimensional atomic layers. This study provides insights into engineering k of multi-layer graphene and boron nitride by strain and into the nature of thermal transport in quasi-two-dimensional and highly anisotropic systems.less

  17. Magneto thermal conductivity of superconducting Nb with intermediate level of impurity

    SciTech Connect (OSTI)

    L.S. Sharath Chandra, M.K. Chattopadhyay, S.B. Roy, V.C. Sahni, G.R. Myneni

    2012-03-01

    Niobium materials with intermediate purity level are used for fabrication of superconducting radio frequency cavities (SCRF), and thermal conductivity is an important parameter influencing the performance of such SCRF cavities. We report here the temperature and magnetic field dependence of thermal conductivity {kappa} for superconducting niobium (Nb) samples, for which the electron mean free path I{sub e}, the phonon mean free path I{sub g}, and the vortex core diameter 2r{sub C} are of the same order of magnitude. The measured thermal conductivity is analyzed using the effective gap model (developed for I{sub e} >> 2r{sub C} (Dubeck et al 1963 Phys. Rev. Lett. 10 98)) and the normal core model (developed for I{sub e} << 2r{sub C} (Ward and Dew-Hughes 1970 J. Phys. C: Solid St. Phys. 3 2245)). However, it is found that the effective gap model is not suitable for low temperatures when I{sub e} {approx} 2r{sub C}. The normal core model, on the other hand, is able to describe {kappa}(T,H) over the entire temperature range except in the field regime between H{sub C1} and H{sub C2} i.e. in the mixed state. It is shown that to understand the complete behavior of {kappa} in the mixed state, the scattering of quasi-particles from the vortex cores and the intervortex quasi-particle tunneling are to be invoked. The quasi-particle scattering from vortices for the present system is understood in terms of the framework of Sergeenkov and Ausloos (1995 Phys. Rev. B 52 3614) extending their approach to the case of Nb. The intervortex tunneling is understood within the framework of Schmidbauer et al (1970 Z. Phys. 240 30). Analysis of the field dependence of thermal conductivity shows that while the quasi-particle scattering from vortices dominates in the low fields, the intervortex quasi-particle tunneling dominates in high fields. Analysis of the temperature dependence of thermal conductivity shows that while the quasi-particle scattering is dominant at low temperatures, the intervortex quasi-particle tunneling is dominant at high temperatures.

  18. A Low Hysteresis NiTiFe Shape Memory Alloy Based Thermal Conduction Switch

    SciTech Connect (OSTI)

    Lemanski, J. L.; Krishnan, V. B.; Manjeri, R. Mahadevan; Vaidyanathan, R.; Notardonato, W. U.

    2006-03-31

    Shape memory alloys possess the ability to return to a preset shape by undergoing a solid state phase transformation at a particular temperature. This work reports on the development and testing of a low temperature thermal conduction switch that incorporates a NiTiFe shape memory element for actuation. The switch was developed to provide a variable conductive pathway between liquid methane and liquid oxygen dewars in order to passively regulate the temperature of methane. The shape memory element in the switch undergoes a rhombohedral or R-phase transformation that is associated with a small hysteresis (typically 1-2 deg. C) and offers the advantage of precision control over a set temperature range. For the NiTiFe alloy used, its thermomechanical processing, subsequent characterization using dilatometry, differential scanning calorimetry and implementation in the conduction switch configuration are addressed.

  19. Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction

    SciTech Connect (OSTI)

    Chen, Chun-Chung; Li, Zhen; Cronin, Stephen B. [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Shi, Li [Department of Mechanical Engineering and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-02-24

    We measure thermal transport across a graphene/hexagonal boron nitride (h-BN) interface by electrically heating the graphene and measuring the temperature difference between the graphene and BN using Raman spectroscopy. Because the temperature of the graphene and BN are measured optically, this approach enables nanometer resolution in the cross-plane direction. A temperature drop of 60?K can be achieved across this junction at high electrical powers (14 mW). Based on the temperature difference and the applied power data, we determine the thermal interface conductance of this junction to be 7.4??10{sup 6}?Wm{sup ?2}K{sup ?1}, which is below the 10{sup 7}10{sup 8}?Wm{sup ?2}K{sup ?1} values previously reported for graphene/SiO{sub 2} interface.

  20. Simplified models of growth, defect formation, and thermal conductivity in diamond chemical vapor deposition

    SciTech Connect (OSTI)

    Coltrin, M.E.; Dandy, D.S.

    1996-04-01

    A simplified surface reaction mechanism is presented for the CVD of diamond thin films. The mechanism also accounts for formation of point defects in the diamond lattice, an alternate, undesirable reaction pathway. Both methyl radicals and atomic C are considered as growth precursors. While not rigorous in all details, the mechanism is useful in describing the CVD diamond process over a wide range of reaction conditions. It should find utility in reactor modeling studies, for example in optimizing diamond growth rate while minimizing defect formation. This report also presents a simple model relating the diamond point-defect density to the thermal conductivity of the material.

  1. Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

    DOE Patents [OSTI]

    Geohegan, David B. (Knoxville, TN) [Knoxville, TN; Ivanov, Ilya N. (Knoxville, TN) [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

    2010-07-27

    Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

  2. Subsurface Temperature, Moisture, Thermal Conductivity and Heat Flux, Barrow, Area A, B, C, D

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Cable, William; Romanovsky, Vladimir

    2014-03-31

    Subsurface temperature data are being collected along a transect from the center of the polygon through the trough (and to the center of the adjacent polygon for Area D). Each transect has five 1.5m vertical array thermistor probes with 16 thermistors each. This dataset also includes soil pits that have been instrumented for temperature, water content, thermal conductivity, and heat flux at the permafrost table. Area C has a shallow borehole of 2.5 meters depth is instrumented in the center of the polygon.

  3. Subsurface Temperature, Moisture, Thermal Conductivity and Heat Flux, Barrow, Area A, B, C, D

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Cable, William; Romanovsky, Vladimir

    Subsurface temperature data are being collected along a transect from the center of the polygon through the trough (and to the center of the adjacent polygon for Area D). Each transect has five 1.5m vertical array thermistor probes with 16 thermistors each. This dataset also includes soil pits that have been instrumented for temperature, water content, thermal conductivity, and heat flux at the permafrost table. Area C has a shallow borehole of 2.5 meters depth is instrumented in the center of the polygon.

  4. Gold-titania interface toughening and thermal conductance enhancement using an organophosphonate nanolayer

    SciTech Connect (OSTI)

    Chow, Philippe K.; O'Brien, Peter; Ramanath, Ganpati; Cardona Quintero, Y.; Ramprasad, R.; Hubert Mutin, P.; Lane, Michael

    2013-05-20

    We demonstrate that a mercaptan-terminated organophosphonate nanolayer at gold-titania interfaces can give rise to two- to three-fold enhancement in the interfacial fracture toughness and thermal conductance. Electron spectroscopy reveals that interfacial delamination occurs at the metal-molecule interface near the gold-sulfur bonds, consistent with density functional theory calculations of bond energies. Qualitative correlation between interfacial fracture toughness and bond energies suggest that organophosphonate nanolayers are resilient to humidity-induced degradation. These results, and the versatility of organophosphonates as surface functionalization agents for technologically relevant materials, unlock uncharted avenues for molecular engineering of interfaces in materials and devices for a variety of applications.

  5. Prediction of Thermal Conductivity for Irradiated SiC/SiC Composites by Informing Continuum Models with Molecular Dynamics Data

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Gao, Fei; Henager, Charles H.; Kurtz, Richard J.

    2014-05-01

    This article proposes a new method to estimate the thermal conductivity of SiC/SiC composites subjected to neutron irradiation. The modeling method bridges different scales from the atomic scale to the scale of a 2D SiC/SiC composite. First, it studies the irradiation-induced point defects in perfect crystalline SiC using molecular dynamics (MD) simulations to compute the defect thermal resistance as a function of vacancy concentration and irradiation dose. The concept of defect thermal resistance is explored explicitly in the MD data using vacancy concentrations and thermal conductivity decrements due to phonon scattering. Point defect-induced swelling for chemical vapor deposited (CVD) SiC as a function of irradiation dose is approximated by scaling the corresponding MD results for perfect crystal ?-SiC to experimental data for CVD-SiC at various temperatures. The computed thermal defect resistance, thermal conductivity as a function of grain size, and definition of defect thermal resistance are used to compute the thermal conductivities of CVD-SiC, isothermal chemical vapor infiltrated (ICVI) SiC and nearly-stoichiometric SiC fibers. The computed fiber and ICVI-SiC matrix thermal conductivities are then used as input for an Eshelby-Mori-Tanaka approach to compute the thermal conductivities of 2D SiC/SiC composites subjected to neutron irradiation within the same irradiation doses. Predicted thermal conductivities for an irradiated Tyranno-SA/ICVI-SiC composite are found to be comparable to available experimental data for a similar composite ICVI-processed with these fibers.

  6. Estimation of host rock thermal conductivities using thetemperature data from the drift-scale test at Yucca Mountain,Nevada

    SciTech Connect (OSTI)

    Mukhopadhyay, Sumitra; Tsang, Y.W.

    2003-11-25

    A large volume of temperature data has been collected from a very large, underground heater test, the Drift Scale Test (DST) at Yucca Mountain, Nevada. The DST was designed to obtain thermal, hydrological, mechanical, and chemical (THMC) data in the unsaturated fractured rock of Yucca Mountain. Sophisticated numerical models have been developed to analyze the collected THMC data. In these analyses, thermal conductivities measured from core samples have been used as input parameters to the model. However, it was not known whether these core measurements represented the true field-scale thermal conductivity of the host rock. Realizing these difficulties, elaborate, computationally intensive geostatistical simulations have also been performed to obtain field-scale thermal conductivity of the host rock from the core measurements. In this paper, we use the temperature data from the DST as the input (instead of the measured core-scale thermal conductivity values) to develop an estimate of the field-scale thermal conductivity values. Assuming a conductive thermal regime, we develop an analytical solution for the temperature rise in the host rock of the DST; and using a nonlinear fitting routine, we obtain a best-fit estimate of field-scale thermal conductivity for the DST host rock. The temperature data collected from the DST shows clear evidence of two distinct thermal regimes: a zone below boiling (wet) and a zone above boiling (dry). We obtain estimates of thermal conductivity for both the wet and dry zones. We also analyze the sensitivity of these estimates to the input heating power of the DST.

  7. Manipulator having thermally conductive rotary joint for transferring heat from a test specimen

    DOE Patents [OSTI]

    Haney, Steven J.; Stulen, Richard H.; Toly, Norman F.

    1985-01-01

    A manipulator for rotatably moving a test specimen in an ultra-high vacuum chamber includes a translational unit movable in three mutually perpendicular directions. A manipulator frame is rigidly secured to the translational unit for rotatably supporting a rotary shaft. A first copper disc is rigidly secured to an end of the rotary shaft for rotary movement within the vacuum chamber. A second copper disc is supported upon the first disc. The second disc receives a cryogenic cold head and does not rotate with the first disc. A sapphire plate is interposed between the first and second discs to prevent galling of the copper material while maintaining high thermal conductivity between the first and second discs. A spring is disposed on the shaft to urge the second disc toward the first disc and compressingly engage the interposed sapphire plate. A specimen mount is secured to the first disc for rotation within the vacuum chamber. The specimen maintains high thermal conductivity with the second disc receiving the cryogenic transfer line.

  8. Manipulator having thermally conductive rotary joint for transferring heat from a test specimen

    DOE Patents [OSTI]

    Haney, S.J.; Stulen, R.H.; Toly, N.F.

    1983-05-03

    A manipulator for rotatably moving a test specimen in an ultra-high vacuum chamber includes a translational unit movable in three mutually perpendicular directions. A manipulator frame is rigidly secured to the translational unit for rotatably supporting a rotary shaft. A first copper disc is rigidly secured to an end of the rotary shaft for rotary movement within the vacuum chamber. A second copper disc is supported upon the first disc. The second disc receives a cryogenic cold head and does not rotate with the first disc. The second disc receives a cryogenic cold head and does not rotate with the first disc. A sapphire plate is interposed between the first and second discs to prevent galling of the copper material while maintaining high thermal conductivity between the first and second discs. A spring is disposed on the shaft to urge the second disc toward the first disc and compressingly engage the interposed sapphire plate. A specimen mount is secured to the first disc for rotation within the vacuum chamber. The specimen maintains high thermal conductivity with the second disc receiving the cryogenic transfer line.

  9. Nonlinear vs. bolometric radiation response and phonon thermal conductance in graphene-superconductor junctions

    SciTech Connect (OSTI)

    Vora, Heli; Nielsen, Bent; Du, Xu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York (United States)

    2014-02-21

    Graphene is a promising candidate for building fast and ultra-sensitive bolometric detectors due to its weak electron-phonon coupling and low heat capacity. In order to realize a practical graphene-based bolometer, several important issues, including the nature of radiation response, coupling efficiency to the radiation and the thermal conductance need to be carefully studied. Addressing these issues, we present graphene-superconductor junctions as a viable option to achieve efficient and sensitive bolometers, with the superconductor contacts serving as hot electron barriers. For a graphene-superconductor device with highly transparent interfaces, the resistance readout in the presence of radio frequency radiation is dominated by non-linear response. On the other hand, a graphene-superconductor tunnel device shows dominantly bolometric response to radiation. For graphene devices fabricated on SiO{sub 2} substrates, we confirm recent theoretical predictions of T{sup 2} temperature dependence of phonon thermal conductance in the presence of disorder in the graphene channel at low temperatures.

  10. Development of an Innovative High-Thermal Conductivity UO2 Ceramic Composites Fuel Pellets with Carbon Nano-Tubes Using Spark Plasma Sintering

    SciTech Connect (OSTI)

    Subhash, Ghatu; Wu, Kuang-Hsi; Tulenko, James

    2014-03-10

    Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. Despite its numerous advantages such as high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation, it suffers from low thermal conductivity that can result in large temperature gradients within the UO2 fuel pellet, causing it to crack and release fission gases. Thermal swelling of the pellets also limits the lifetime of UO2 fuel in the reactor. To mitigate these problems, we propose to develop novel UO2 fuel with uniformly distributed carbon nanotubes (CNTs) that can provide high-conductivity thermal pathways and can eliminate fuel cracking and fission gas release due to high temperatures. CNTs have been investigated extensively for the past decade to explore their unique physical properties and many potential applications. CNTs have high thermal conductivity (6600 W/mK for an individual single- walled CNT and >3000 W/mK for an individual multi-walled CNT) and high temperature stability up to 2800C in vacuum and about 750C in air. These properties make them attractive candidates in preparing nano-composites with new functional properties. The objective of the proposed research is to develop high thermal conductivity of UO2CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (515 min) called spark plasma sintering (SPS) in which a mixture of CNTs and UO2 powder are used to make composites with different volume fractions of CNTs. Incorporation of these nanoscale materials plays a fundamentally critical role in controlling the performance and stability of UO2 fuel. We will use a novel in situ growth process to grow CNTs on UO2 particles for rapid sintering and develop UO2-CNT composites. This method is expected to provide a uniform distribution of CNTs at various volume fractions so that a high thermally conductive UO2-CNT composite is obtained with a minimal volume fraction of CNTs. The mixtures are sintered in the SPS facility at a range of temperatures, pressures, and time durations so as to identify the optimal processing conditions to obtain the desired microstructure of sintered UO2-CNT pellets. The second objective of the proposed work is to identify the optimal volume fraction of CNTs in the microstructure of the composites that provides the desired high thermal conductivity yet retaining the mechanical strength required for efficient function as a reactor fuel. We will systematically study the resulting microstructure (grain size, porosity, distribution of CNTs, etc.) obtained at various SPS processing conditions using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscope (TEM). We will conduct indentation hardness measurements and uniaxial strength measurements as a function of volume fraction of CNTs to determine the mechanical strength and compare them to the properties of UO2. The fracture surfaces will be studied to determine the fracture characteristics that may relate to the observed cracking during service. Finally, we will perform thermal conductivity measurements on all the composites up to 1000 C. This study will relate the microstructure, mechanical properties, and thermal properties at various volume fractions of CNTs. The overall intent is to identify optimal processing conditions that will provide a well-consolidated compact with optimal microstructure and thermo-mechanical properties. The deliverables include: (1) fully characterized UO2-CNT composite with optimal CNT volume fraction and high thermal conductivity and (2) processing conditions for production of UO2-CNT composite pellets using SPS method.

  11. Tensile strains give rise to strong size effects for thermal conductivities of silicene, germanene and stanene

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kuang, Youdi D.; Lindsay, Lucas R.; Shi, Sanqiang Q.; Zhen, Guangping P.

    2016-01-11

    Based on first principles calculations and self-consistent solution of linearized Boltzmann-Peierls equation for phonon transport approach within a three-phonon scattering framework, we characterize lattice thermal conductivities k of freestanding silicene, germanene and stanene under different isotropic tensile strains and temperatures. We find a strong size dependence of k for silicene with tensile strain, i.e., divergent k with increasing system size, in contrast, the intrinsic room temperature k for unstrained silicene converges with system size to 19.34 W/m–1 K–1 by 178 nm. The room temperature k of strained silicene becomes as large as that of bulk silicon by 84 m, indicatingmore » the possibility of using strain in silicene to manipulate k for thermal management. The relative contribution to the intrinsic k from out-of-plane acoustic modes is largest for unstrained silicene, –39% at room temperature. The single mode relaxation time approximation, which works reasonably well for bulk silicon, fails to appropriately describe phonon thermal transport in silicene, germanene and stanene within the temperature range considered. For large samples of silicene, k increases with tensile strain, peaks at –7% strain and then decreases with further strain. In germanene and stanene increasing strain hardens and stabilizes long wavelength out-of-plane acoustic phonons, and leads to similar k behaviors to those of silicene. As a result, these findings further our understanding of phonon dynamics in group-IV buckled monolayers and may guide transfer and fabrication techniques of these freestanding samples and engineering k by size and strain for applications of thermal management and thermoelectricity.« less

  12. Experimental determination of single-crystal halite thermal conductivity, diffusivity and specific heat from -75C to 300C

    SciTech Connect (OSTI)

    Urquhart, Alexander; Bauer, Stephen

    2015-05-19

    The thermal properties of halite have broad practical importance, from design and long-term modeling of nuclear waste repositories to analysis and performance assessment of underground natural gas, petroleum and air storage facilities. Using a computer-controlled transient plane source method, single-crystal halite thermal conductivity, thermal diffusivity and specific heat were measured from -75C to 300C. These measurements reproduce historical high-temperature experiments and extend the lower temperature extreme into cryogenic conditions. Measurements were taken in 25-degree increments from -75C to 300C. Over this temperature range, thermal conductivity decreases by a factor of 3.7, from 9.975 to 2.699 W/mK , and thermal diffusivity decreases by a factor of 3.6, from 5.032 to 1.396 mm/s. Specific heat does not appear to be temperature dependent, remaining near 2.0 MJ/mK at all temperatures. This work is intended to develop and expand the existing dataset of halite thermal properties, which are of particular value in defining the parameters of salt storage thermophysical models. The work was motivated by a need for thermal conductivity values in a mixture theory model used to determine bulk thermal conductivity of reconsolidating crushed salt.

  13. Thermal conductivity of Bi{sub 2}Te{sub 3} tilted nanowires, a molecular dynamics study

    SciTech Connect (OSTI)

    Li, Shen Lacroix, David; Termentzidis, Konstantinos; Chaput, Laurent; Stein, Nicolas; Frantz, Cedric

    2015-06-08

    Evidence for an excellent compromise between structural stability and low thermal conductivity has been achieved with tilted Bi{sub 2}Te{sub 3} nanowires. The latter ones were recently fabricated and there is a need in modeling and characterization. The structural stability and the thermal conductivity of Bi{sub 2}Te{sub 3} nanowires along the tilted [015]* direction and along the [010] direction have been explored. For the two configurations of nanowires, the effect of the length and the cross section on the thermal conductivity is discussed. The thermal conductivity of infinite size tilted nanowire is 0.34?W/m K, significantly reduced compared to nanowire along the [010] direction (0.59?W/m K). This reveals that in Bi{sub 2}Te{sub 3} nanowires the structural anisotropy can be as important as size effects to reduce the thermal conductivity. The main reason is the reduction of the phonon mean free path which is found to be 1.7?nm in the tilted nanowires, compared to 5.3?nm for the nanowires along the [010] direction. The fact that tilted Bi{sub 2}Te{sub 3} nanowire is mechanically stable and it has extremely low thermal conductivity suggests these nanowires as a promising material for future thermoelectric generation application.

  14. Method of making improved gas storage carbon with enhanced thermal conductivity

    DOE Patents [OSTI]

    Burchell, Timothy D.; Rogers, Michael R.

    2002-11-05

    A method of making an adsorbent carbon fiber based monolith having improved methane gas storage capabilities is disclosed. Additionally, the monolithic nature of the storage carbon allows it to exhibit greater thermal conductivity than conventional granular activated carbon or powdered activated carbon storage beds. The storage of methane gas is achieved through the process of physical adsorption in the micropores that are developed in the structure of the adsorbent monolith. The disclosed monolith is capable of storing greater than 150 V/V of methane [i.e., >150 STP (101.325 KPa, 298K) volumes of methane per unit volume of storage vessel internal volume] at a pressure of 3.5 MPa (500 psi).

  15. Thermal conductivity in large-J two-dimensional antiferromagnets: Role of phonon scattering

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chernyshev, A. L.; Brenig, Wolfram

    2015-08-05

    Different types of relaxation processes for magnon heat current are discussed, with a particular focus on coupling to three-dimensional phonons. There is thermal conductivity by these in-plane magnetic excitations using two distinct techniques: Boltzmann formalism within the relaxation-time approximation and memory-function approach. Also considered are the scattering of magnons by both acoustic and optical branches of phonons. We demonstrate an accord between the two methods, regarding the asymptotic behavior of the effective relaxation rates. It is strongly suggested that scattering from optical or zone-boundary phonons is important for magnon heat current relaxation in a high-temperature window of ΘD≲T<< J.

  16. Lattice Anharmonicity and Thermal Conductivity from Compressive Sensing of First-Principles Calculations

    SciTech Connect (OSTI)

    Zhou, Fei; Nielson, Weston; Xia, Yi; Ozoli?, Vidvuds

    2014-10-01

    First-principles prediction of lattice thermal conductivity ?L of strongly anharmonic crystals is a long-standing challenge in solid-state physics. Making use of recent advances in information science, we propose a systematic and rigorous approach to this problem, compressive sensing lattice dynamics. Compressive sensing is used to select the physically important terms in the lattice dynamics model and determine their values in one shot. Nonintuitively, high accuracy is achieved when the model is trained on first-principles forces in quasirandom atomic configurations. The method is demonstrated for Si, NaCl, and Cu12Sb4S13, an earth-abundant thermoelectric with strong phonon-phonon interactions that limit the room-temperature ?L to values near the amorphous limit.

  17. Microstructure and thermal conductivity of surfactant-free NiO nanostructures

    SciTech Connect (OSTI)

    Sahoo, Pranati; Misra, Dinesh K.; Salvador, Jim; Makongo, Julien P.A.; Chaubey, Girija S.; Takas, Nathan J.; Wiley, John B.; Poudeu, Pierre F.P.

    2012-06-15

    High purity, nanometer sized surfactant-free nickel oxide (NiO) particles were produced in gram scale using a solution combustion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), gas pycnometry and gas adsorption analysis (BET). The average particle size of the as-synthesized NiO increases significantly with the preheating temperature of the furnace, while the specific surface area decreases. A BET specific surface area of {approx}100 m{sup 2}/g was obtained for NiO nanoparticles with size as small as 3 nm synthesized at 300 Degree-Sign C. The thermal conductivity ({kappa}) of pressed pellets of the synthesized NiO nanoparticles obtained using spark plasma sintering (SPS) and uniaxial hot pressing is drastically decreased ({approx}60%) compared to that of NiO single crystal. This strong reduction in {kappa} with particle size suggests the suitability of the synthesized surfactant-free NiO nanoparticles for use as nanoinclusions when designing high performance materials for waste heat recovery. - Graphical abstract: Highly efficient phonon scattering by surfactant-free NiO nanostructures obtained by solution combustion of a mixture of nickel (II) nitrate hexahydrate (oxidizer) and urea (fuel) at various temperatures. Highlights: Black-Right-Pointing-Pointer Fast synthesis of surfactant-free NiO nanoparticles with controllable size. Black-Right-Pointing-Pointer High specific surface area for NiO nanoparticles with size range from 3 to 7 nm. Black-Right-Pointing-Pointer Strong reduction of the thermal conductivity with decreasing particle size. Black-Right-Pointing-Pointer NiO as nanoinclusions in high performance materials for energy conversion.

  18. Density dependence of the room temperature thermal conductivity of atomic layer deposition-grown amorphous alumina (Al{sub 2}O{sub 3})

    SciTech Connect (OSTI)

    Gorham, Caroline S.; Gaskins, John T.; Hopkins, Patrick E.; Parsons, Gregory N.; Losego, Mark D.

    2014-06-23

    We report on the thermal conductivity of atomic layer deposition-grown amorphous alumina thin films as a function of atomic density. Using time domain thermoreflectance, we measure the thermal conductivity of the thin alumina films at room temperature. The thermal conductivities vary ?35% for a nearly 15% change in atomic density and are substrate independent. No density dependence of the longitudinal sound speeds is observed with picosecond acoustics. The density dependence of the thermal conductivity agrees well with a minimum limit to thermal conductivity model that is modified with a differential effective-medium approximation.

  19. ROTATING SOLAR JETS IN SIMULATIONS OF FLUX EMERGENCE WITH THERMAL CONDUCTION

    SciTech Connect (OSTI)

    Fang, Fang; Fan, Yuhong; McIntosh, Scott W.

    2014-07-01

    We study the formation of coronal jets through numerical simulation of the emergence of a twisted magnetic flux rope into a pre-existing open magnetic field. Reconnection inside the emerging flux rope in addition to that between the emerging and pre-existing fields give rise to the violent eruption studied. The simulated event closely resembles the coronal jets ubiquitously observed by the X-Ray Telescope on board Hinode and demonstrates that heated plasma is driven into the extended atmosphere above. Thermal conduction implemented in the model allows us to qualitatively compare simulated and observed emission from such events. We find that untwisting field lines after the reconnection drive spinning outflows of plasma in the jet column. The Poynting flux in the simulated jet is dominated by the untwisting motions of the magnetic fields loaded with high-density plasma. The simulated jet is comprised of ''spires'' of untwisting field that are loaded with a mixture of cold and hot plasma and exhibit rotational motion of order 20 km s{sup –1} and match contemporary observations.

  20. Measurements of the apparent thermal conductivity of multi-layer insulation between 20 K and 90 K

    SciTech Connect (OSTI)

    Hurd, Joseph A.; Van Sciver, Steven W.

    2014-01-29

    NASA has the need to efficiently store cryogenic propellants in space for long periods of time. One method to improve storage efficiency is to use multi-layer insulation (MLI), a technique that minimizes the boiling rate due to radiation heat transfer. Typically, the thermal performance of MLI is determined by measuring the rate of evaporation of liquid nitrogen from a calibrated cryostat. The main limitation with this method is that testing conditions are restricted by the boiling temperature of the LN{sub 2}, which may not match the requirements of the application. The Multi-Layer Insulation Thermal Conductivity Experiment (MIKE) at the National High Magnetic Field Laboratory is capable of measuring the effective thermal conductivity of MLI at variable boundary temperatures. MIKE uses cryo-refrigerators to control boundary temperatures in the calorimeter and a calibrated thermal link to measure the heat load. To make the measurements requested by NASA, MIKE needed to be recalibrated for the 20 K to 90 K range. Also, due to the expectation of a lower heat transfer rate, the heat load support rod material was changed to one with a lower thermal conductivity to ensure the temperature difference seen on the cold rod could be measurable at the estimated heat load. Presented are the alterations to MIKE including calibration data and heat load measurements on new load-bearing MLI supplied by NASA.

  1. Superior thermoelectric performance in PbTe-PbS pseudo-binary. Extremely low thermal conductivity and modulated carrier concentration

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wu, D.; Zhao, L. -D.; Tong, X.; Li, W.; Wu, L.; Tan, Q.; Pei, Y.; Huang, L.; Li, J. -F.; Zhu, Y.; et al

    2015-05-19

    Lead chalcogenides have exhibited their irreplaceable role as thermoelectric materials at the medium temperature range, owing to highly degenerate electronic bands and intrinsically low thermal conductivities. PbTe-PbS pseudo-binary has been paid extensive attentions due to the even lower thermal conductivity which originates largely from the coexistence of both alloying and phase-separated precipitations. To investigate the competition between alloying and phase separation and its pronounced effect on the thermoelectric performance in PbTe-PbS, we systematically studied Spark Plasma Sintered (SPSed), 3 at% Na- doped (PbTe)1-x(PbS)x samples with x=10%, 15%, 20%, 25%, 30% and 35% by means of transmission electron microscopy (TEM) observationsmore » and theoretical calculations. Corresponding to the lowest lattice thermal conductivity as a result of the balance between point defect- and precipitates- scattering, the highest figure of merit ZT~2.3 was obtained at 923 K when PbS phase fraction x is at 20%. The consistently lower lattice thermal conductivities in SPSed samples compared with corresponding ingots, resulting from the powdering and follow-up consolidation processes, also contribute to the observed superior ZT. Notably, the onset of carrier concentration modulation ~600 K due to excessive Na’s diffusion and re-dissolution leads to the observed saturations of electrical transport properties, which is believed equally crucial to the outstanding thermoelectric performance of SPSed PbTe-PbS samples.« less

  2. Superior thermoelectric performance in PbTe-PbS pseudo-binary. Extremely low thermal conductivity and modulated carrier concentration

    SciTech Connect (OSTI)

    Wu, D.; Zhao, L. -D.; Tong, X.; Li, W.; Wu, L.; Tan, Q.; Pei, Y.; Huang, L.; Li, J. -F.; Zhu, Y.; Kanatzidis, M. G.; He, J.

    2015-05-19

    Lead chalcogenides have exhibited their irreplaceable role as thermoelectric materials at the medium temperature range, owing to highly degenerate electronic bands and intrinsically low thermal conductivities. PbTe-PbS pseudo-binary has been paid extensive attentions due to the even lower thermal conductivity which originates largely from the coexistence of both alloying and phase-separated precipitations. To investigate the competition between alloying and phase separation and its pronounced effect on the thermoelectric performance in PbTe-PbS, we systematically studied Spark Plasma Sintered (SPSed), 3 at% Na- doped (PbTe)1-x(PbS)x samples with x=10%, 15%, 20%, 25%, 30% and 35% by means of transmission electron microscopy (TEM) observations and theoretical calculations. Corresponding to the lowest lattice thermal conductivity as a result of the balance between point defect- and precipitates- scattering, the highest figure of merit ZT~2.3 was obtained at 923 K when PbS phase fraction x is at 20%. The consistently lower lattice thermal conductivities in SPSed samples compared with corresponding ingots, resulting from the powdering and follow-up consolidation processes, also contribute to the observed superior ZT. Notably, the onset of carrier concentration modulation ~600 K due to excessive Nas diffusion and re-dissolution leads to the observed saturations of electrical transport properties, which is believed equally crucial to the outstanding thermoelectric performance of SPSed PbTe-PbS samples.

  3. Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation

    SciTech Connect (OSTI)

    Janne Pakrinen; Marat Khafizov; Lingfeng He; Chris Wetland; Jian Gan; Andrew T. Nelson; David H Hurley; Anter El-Azab; Todd R Allen

    2014-11-01

    The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in x-ray diffraction after ion irradiation up to 51016 He2+/cm2 at low-temperature (< 200 C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 m thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 m) in the sample subjected to 51016 He2+/cm2, the highest fluence reached, while similar features were not detected at 91015 He2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55 % for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.

  4. Temperature, thermal-conductivity, and heat-flux data,Raft River...

    Open Energy Info (EERE)

    conductivity; United States; USGS Authors Urban, T.C.; Diment, W.H.; Nathenson, M.; Smith, E.P.; Ziagos, J.P.; Shaeffer and M.H. Published Open-File Report - U. S. Geological...

  5. Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model

    SciTech Connect (OSTI)

    Huang, Hai; Plummer, Mitchell; Podgorney, Robert

    2013-02-01

    Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

  6. Method for the thermal characterization, visualization, and integrity evaluation of conducting material samples or complex structures

    DOE Patents [OSTI]

    Ortiz, Marcos G. (Idaho Falls, ID)

    1992-01-01

    A method for modeling a conducting material sample or structure (herein called a system) as at least two regions which comprise an electrical network of resistances, for measuring electric resistance between at least two selected pairs of external leads attached to the surface of the system, wherein at least one external lead is attached to the surface of each of the regions, and, using basic circuit theory, for translating measured resistances into temperatures or thermophysical properties in corresponding regions of the system.

  7. Electrical network method for the thermal or structural characterization of a conducting material sample or structure

    DOE Patents [OSTI]

    Ortiz, M.G.

    1993-06-08

    A method for modeling a conducting material sample or structure system, as an electrical network of resistances in which each resistance of the network is representative of a specific physical region of the system. The method encompasses measuring a resistance between two external leads and using this measurement in a series of equations describing the network to solve for the network resistances for a specified region and temperature. A calibration system is then developed using the calculated resistances at specified temperatures. This allows for the translation of the calculated resistances to a region temperature. The method can also be used to detect and quantify structural defects in the system.

  8. Electrical network method for the thermal or structural characterization of a conducting material sample or structure

    DOE Patents [OSTI]

    Ortiz, Marco G. (Idaho Falls, ID)

    1993-01-01

    A method for modeling a conducting material sample or structure system, as an electrical network of resistances in which each resistance of the network is representative of a specific physical region of the system. The method encompasses measuring a resistance between two external leads and using this measurement in a series of equations describing the network to solve for the network resistances for a specified region and temperature. A calibration system is then developed using the calculated resistances at specified temperatures. This allows for the translation of the calculated resistances to a region temperature. The method can also be used to detect and quantify structural defects in the system.

  9. Method for the thermal characterization, visualization, and integrity evaluation of conducting material samples or complex structures

    DOE Patents [OSTI]

    Ortiz, M.G.

    1992-11-24

    Disclosed is a method for modeling a conducting material sample or structure (herein called a system) as at least two regions which comprise an electrical network of resistances, for measuring electric resistance between at least two selected pairs of external leads attached to the surface of the system, wherein at least one external lead is attached to the surface of each of the regions, and, using basic circuit theory, for translating measured resistances into temperatures or thermophysical properties in corresponding regions of the system. 16 figs.

  10. Thermal Conductivity Measurement of Xe-Implanted Uranium Dioxide Thick Films using Multilayer Laser Flash Analysis

    SciTech Connect (OSTI)

    Nelson, Andrew T.

    2012-08-30

    The Fuel Cycle Research and Development program's Advanced Fuels campaign is currently pursuing use of ion beam assisted deposition to produce uranium dioxide thick films containing xenon in various morphologies. To date, this technique has provided materials of interest for validation of predictive fuel performance codes and to provide insight into the behavior of xenon and other fission gasses under extreme conditions. In addition to the structural data provided by such thick films, it may be possible to couple these materials with multilayer laser flash analysis in order to measure the impact of xenon on thermal transport in uranium dioxide. A number of substrate materials (single crystal silicon carbide, molybdenum, and quartz) containing uranium dioxide films ranging from one to eight microns in thickness were evaluated using multilayer laser flash analysis in order to provide recommendations on the most promising substrates and geometries for further investigation. In general, the uranium dioxide films grown to date using ion beam assisted deposition were all found too thin for accurate measurement. Of the substrates tested, molybdenum performed the best and looks to be the best candidate for further development. Results obtained within this study suggest that the technique does possess the necessary resolution for measurement of uranium dioxide thick films, provided the films are grown in excess of fifty microns. This requirement is congruent with the material needs when viewed from a fundamental standpoint, as this length scale of material is required to adequately sample grain boundaries and possible second phases present in ceramic nuclear fuel.

  11. Fully-coupled engineering and mesoscale simulations of thermal conductivity in UO2 fuel using an implicit multiscale approach

    SciTech Connect (OSTI)

    Michael Tonks; Derek Gaston; Cody Permann; Paul Millett; Glen Hansen; Chris Newman

    2009-08-01

    Reactor fuel performance is sensitive to microstructure changes during irradiation (such as fission gas and pore formation). This study proposes an approach to capture microstructural changes in the fuel by a two-way coupling of a mesoscale phase field irradiation model to an engineering scale, finite element calculation. This work solves the multiphysics equation system at the engineering-scale in a parallel, fully-coupled, fully-implicit manner using a preconditioned Jacobian-free Newton Krylov method (JFNK). A sampling of the temperature at the Gauss points of the coarse scale is passed to a parallel sequence of mesoscale calculations within the JFNK function evaluation phase of the calculation. The mesoscale thermal conductivity is calculated in parallel, and the result is passed back to the engineering-scale calculation. As this algorithm is fully contained within the JFNK function evaluation, the mesoscale calculation is nonlinearly consistent with the engineering-scale calculation. Further, the action of the Jacobian is also consistent, so the composite algorithm provides the strong nonlinear convergence properties of Newton's method. The coupled model using INL's \\bison\\ code demonstrates quadratic nonlinear convergence and good parallel scalability. Initial results predict the formation of large pores in the hotter center of the pellet, but few pores on the outer circumference. Thus, the thermal conductivity is is reduced in the center of the pellet, leading to a higher internal temperature than that in an unirradiated pellet.

  12. The thermal conductivity of mixed fuel UxPu1-xO2: molecular dynamics simulations

    SciTech Connect (OSTI)

    Liu, Xiang-Yang; Cooper, Michael William Donald; Stanek, Christopher Richard; Andersson, Anders David Ragnar

    2015-10-16

    Mixed oxides (MOX), in the context of nuclear fuels, are a mixture of the oxides of heavy actinide elements such as uranium, plutonium and thorium. The interest in the UO2-PuO2 system arises from the fact that these oxides are used both in fast breeder reactors (FBRs) as well as in pressurized water reactors (PWRs). The thermal conductivity of UO2 fuel is an important material property that affects fuel performance since it is the key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. For this reason it is important to understand the thermal conductivity of MOX fuel and how it differs from UO2. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of mixing on the thermal conductivity of UxPu1-xO2, as a function of PuO2 concentrations, for a range of temperatures, 300 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel.

  13. Experimental determination of single-crystal halite thermal conductivity, diffusivity and specific heat from -75°C to 300°C

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Urquhart, Alexander; Bauer, Stephen

    2015-05-19

    The thermal properties of halite have broad practical importance, from design and long-term modeling of nuclear waste repositories to analysis and performance assessment of underground natural gas, petroleum and air storage facilities. Using a computer-controlled transient plane source method, single-crystal halite thermal conductivity, thermal diffusivity and specific heat were measured from -75°C to 300°C. These measurements reproduce historical high-temperature experiments and extend the lower temperature extreme into cryogenic conditions. Measurements were taken in 25-degree increments from -75°C to 300°C. Over this temperature range, thermal conductivity decreases by a factor of 3.7, from 9.975 to 2.699 W/mK , and thermal diffusivitymore » decreases by a factor of 3.6, from 5.032 to 1.396 mm²/s. Specific heat does not appear to be temperature dependent, remaining near 2.0 MJ/m³K at all temperatures. This work is intended to develop and expand the existing dataset of halite thermal properties, which are of particular value in defining the parameters of salt storage thermophysical models. The work was motivated by a need for thermal conductivity values in a mixture theory model used to determine bulk thermal conductivity of reconsolidating crushed salt.« less

  14. Effects of chemical intermixing on electrical and thermal contact conductances at metallized bismuth and antimony telluride interfaces

    SciTech Connect (OSTI)

    Devender,; Mehta, Rutvik J.; Ramanath, Ganpati; Lofgreen, Kelly; Mahajan, Ravi; Yamaguchi, Masashi; Borca-Tasciuc, Theodorian

    2015-03-15

    Tailoring electrical and thermal contact conductivities (?{sub c} and ?{sub c}) across metallized pnictogen chalcogenide interfaces is key for realizing efficient thermoelectric devices. The authors report that Cu, Ni, Ti, and Ta diffusion and interfacial telluride formation with n-Bi{sub 2}Te{sub 3} and p-Sb{sub 2}Te{sub 3} influence both ?{sub c} and ?{sub c}. Cu metallization yields the highest ?{sub c} and the lowest ?{sub c}, correlating with maximal metal diffusion and copper telluride formation. Ni diffuses less and yields the highest ?{sub c} with Sb{sub 2}Te{sub 3} due to p-type nickel telluride formation, which diminishes ?{sub c} improvement with n-Bi{sub 2}Te{sub 3} interfaces. Ta and Ti contacts yield the lowest properties similar to that in Ni-metallized structures. These correlations between interfacial diffusion and phase formation on electronic and thermal transport properties will be important for devising suitable metallization for thermoelectric devices.

  15. Thermal conductivity of bulk and nanowire Mg₂SixSn1–x alloys from first principles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Wu; Lindsay, L.; Broido, D. A.; Stewart, Derek A.; Mingo, Natalio

    2012-11-29

    The lattice thermal conductivity (κ) of the thermoelectric materials, Mg₂Si, Mg₂Sn, and their alloys, are calculated for bulk and nanowires, without adjustable parameters. We find good agreement with bulk experimental results. For large nanowire diameters, size effects are stronger for the alloy than for the pure compounds. For example, in 200 nm diameter nanowires κ is lower than its bulk value by 30%, 20%, and 20% for Mg₂Si₀.₆Sn₀.₄, Mg₂Si, and Mg₂Sn, respectively. For nanowires less than 20 nm thick, the relative decrease surpasses 50%, and it becomes larger in the pure compounds than in the alloy. At room temperature, κmore » of Mg₂SixSn1–x is less sensitive to nanostructuring size effects than SixGe1–x, but more sensitive than PbTexSe1–x. This suggests that further improvement of Mg₂SixSn1–x as a nontoxic thermoelectric may be possible.« less

  16. Glass-Like Thermal Conductivity of (010)-Textured Lanthanum-Doped Strontium Niobate Synthesized with Wet Chemical Deposition

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Foley, Brian M.; Brown-Shaklee, Harlan J.; Campion, Michael J.; Medlin, Douglas L.; Clem, Paul G.; Ihlefeld, Jon F.; Hopkins, Patrick E.

    2014-11-08

    We have measured the cross-plane thermal conductivity (κ) of (010)-textured, undoped, and lanthanum-doped strontium niobate (Sr2-xLaxNb2O7-δ) thin films via time-domain thermoreflectance. Then the thin films were deposited on (001)-oriented SrTiO3 substrates via the highly-scalable technique of chemical solution deposition. We find that both film thickness and lanthanum doping have little effect on κ, suggesting that there is a more dominant phonon scattering mechanism present in the system; namely the weak interlayer-bonding along the b-axis in the Sr2Nb2O7 parent structure. We also compare our experimental results with two variations of the minimum-limit model for κ and discuss the nature of transportmore » in material systems with weakly-bonded layers. The low cross-plane κ of these scalably-fabricated films is comparable to that of similarly layered niobate structures grown epitaxially.« less

  17. Abnormal thermal conductivity in tetragonal tungsten bronze Ba{sub 6−x}Sr{sub x}Nb{sub 10}O{sub 30}

    SciTech Connect (OSTI)

    Kolodiazhnyi, T. Sakurai, H.; Vasylkiv, O.; Borodianska, H.; Mozharivskyj, Y.

    2014-03-17

    Ba{sub 6−x}Sr{sub x}Nb{sub 10}O{sub 30} solid solution with 0 ≤ x ≤ 6 crystallizes in centrosymmetric tetragonal “tungsten bronze” structure (space group P4/mbm). We report on the x dependence of thermal conductivity of polycrystalline samples measured in the 2–400 K temperature interval. Substitution of Sr for Ba brings about a significant decrease in thermal conductivity at x ≥ 3 accompanied by development of a low-temperature (T ≈ 10–30 K) “plateau” region reminiscent of a glass-like compounds. We explain this behaviour based on a size-driven site occupancy and atomic displacement parameters associated with an alkaline earth atomic positions in the title compounds.

  18. Non Linear Conjugate Gradient

    Energy Science and Technology Software Center (OSTI)

    2006-11-17

    Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more »The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less

  19. Numerical analysis of heat transfer by conduction and natural convection in loose-fill fiberglass insulation--effects of convection on thermal performance

    SciTech Connect (OSTI)

    Delmas, A.A.; Wilkes, K.E.

    1992-04-01

    A two-dimensional code for solving equations of convective heat transfer in porous media is used to analyze heat transfer by conduction and convection in the attic insulation configuration. The particular cases treated correspond to loose-fill fiberglass insulation, which is characterized by high porosity and air permeability. The effects of natural convection on the thermal performance of the insulation are analyzed for various densities, permeabilities, and thicknesses of insulation. With convection increasing the total heat transfer through the insulation, the thermal resistance was found to decrease as the temperature difference across the insulating material increases. The predicted results for the thermal resistance are compared with data obtained in the large-scale climate simulator at the Roof Research Center using the attic test module, where the same phenomenon has already been observed. The way the wood joists within the insulation influence the start of convection is studied for differing thermophysical and dynamic properties of the insulating material. The presence of wood joists induces convection at a lower temperature difference.

  20. Gradient Resources | Open Energy Information

    Open Energy Info (EERE)

    Gradient Resources Jump to: navigation, search Logo: Gradient Resources Name: Gradient Resources Address: 9670 Gateway Drive, Suite 200 Place: Reno, Nevada Zip: 89521 Region:...

  1. Thermal conductivity in large-J two-dimensional antiferromagnets: Role of phonon scattering

    SciTech Connect (OSTI)

    Chernyshev, A. L.; Brenig, Wolfram

    2015-08-05

    Different types of relaxation processes for magnon heat current are discussed, with a particular focus on coupling to three-dimensional phonons. There is thermal conductivity by these in-plane magnetic excitations using two distinct techniques: Boltzmann formalism within the relaxation-time approximation and memory-function approach. Also considered are the scattering of magnons by both acoustic and optical branches of phonons. We demonstrate an accord between the two methods, regarding the asymptotic behavior of the effective relaxation rates.

    It is strongly suggested that scattering from optical or zone-boundary phonons is important for magnon heat current relaxation in a high-temperature window of ?D?T<< J.

  2. Low thermal budget photonic processing of highly conductive Cu interconnects based on CuO nanoinks. Potential for flexible printed electronics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rager, Matthew S.; Aytug, Tolga; Veith, Gabriel M.; Joshi, Pooran C.

    2015-12-31

    The developing field of printed electronics nanoparticle based inks such as CuO show great promise as a low-cost alternative to other metal-based counterparts (e.g., silver). In particular, CuO inks significantly eliminate the issue of particle oxidation, before and during the sintering process, that is prevalent in Cu-based formulations. We report here the scalable and low-thermal budget photonic fabrication of Cu interconnects employing a roll-to-roll compatible pulse-thermal-processing (PTP) technique that enables phase reduction and subsequent sintering of inkjet-printed CuO patterns onto flexible polymer templates. Detailed investigations of curing and sintering conditions were performed to understand the impact of PTP system conditionsmore » on the electrical performance of the Cu patterns. Specifically, the impact of energy and power of photonic pulses on print conductivity was systematically studied by varying the following key processing parameters: pulse intensity, duration and sequence. Through optimization of such parameters, highly conductive prints in < 1 s with resistivity values as low as 100 n m has been achieved. We also observed that the introduction of an initial ink-drying step in ambient atmosphere, after the printing and before sintering, leads to significant improvements in mechanical integrity and electrical performance of the printed Cu patterns. Moreover, the viability of CuO reactive inks, coupled with the PTP technology and pre ink-drying protocols, has also been demonstrated for the additive integration of a low-cost Cu temperature sensor onto a flexible polymer substrate.« less

  3. Pumpernickel Valley Geothermal Project Thermal Gradient Wells...

    Open Energy Info (EERE)

    the geothermal activity in the valley are two areas with hot springs, seepages, and wet groundvegetation anomalies near the Pumpernickel Valley fault, which indicate that the...

  4. Accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures, Part II: Experimental comparison and verification of methods. Volume 2, In situ conductivity data

    SciTech Connect (OSTI)

    Kauffman, R.

    1995-09-01

    Data are presented for the accelerated screening methods for determining chemical and thermal stability of refrigerant-lubricant mixtures.

  5. Thermal conductivity of bulk and nanowire Mg?SixSn1x alloys from first principles

    SciTech Connect (OSTI)

    Li, Wu; Lindsay, L.; Broido, D. A.; Stewart, Derek A.; Mingo, Natalio

    2012-11-29

    The lattice thermal conductivity (?) of the thermoelectric materials, Mg?Si, Mg?Sn, and their alloys, are calculated for bulk and nanowires, without adjustable parameters. We find good agreement with bulk experimental results. For large nanowire diameters, size effects are stronger for the alloy than for the pure compounds. For example, in 200 nm diameter nanowires ? is lower than its bulk value by 30%, 20%, and 20% for Mg?Si?.?Sn?.?, Mg?Si, and Mg?Sn, respectively. For nanowires less than 20 nm thick, the relative decrease surpasses 50%, and it becomes larger in the pure compounds than in the alloy. At room temperature, ? of Mg?SixSn1x is less sensitive to nanostructuring size effects than SixGe1x, but more sensitive than PbTexSe1x. This suggests that further improvement of Mg?SixSn1x as a nontoxic thermoelectric may be possible.

  6. Joining of Tungsten Armor Using Functional Gradients

    SciTech Connect (OSTI)

    John Scott O'Dell

    2006-12-31

    The joining of low thermal expansion armor materials such as tungsten to high thermal expansion heat sink materials has been a major problem in plasma facing component (PFC) development. Conventional planar bonding techniques have been unable to withstand the high thermal induced stresses resulting from fabrication and high heat flux testing. During this investigation, innovative functional gradient joints produced using vacuum plasma spray forming techniques have been developed for joining tungsten armor to copper alloy heat sinks. A model was developed to select the optimum gradient architecture. Based on the modeling effort, a 2mm copper rich gradient was selected. Vacuum plasma pray parameters and procedures were then developed to produce the functional gradient joint. Using these techniques, dual cooling channel, medium scale mockups (32mm wide x 400mm length) were produced with vacuum plasma spray formed tungsten armor. The thickness of the tungsten armor was up to 5mm thick. No evidence of debonding at the interface between the heat sink and the vacuum plasma sprayed material was observed.

  7. Short wavelength ion temperature gradient turbulence

    SciTech Connect (OSTI)

    Chowdhury, J.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar (India); Brunner, S.; Lapillonne, X.; Villard, L. [CRPP, Association EURATOM-Confederation Suisse, EPFL, 1015 Lausanne (Switzerland); Jenko, F. [Max-Planck-Institut fuer Plasmaphysik Boltzmannstr. 2, D-85748 Garching (Germany)

    2012-10-15

    The ion temperature gradient (ITG) mode in the high wavenumber regime (k{sub y}{rho}{sub s}>1), referred to as short wavelength ion temperature gradient mode (SWITG) is studied using the nonlinear gyrokinetic electromagnetic code GENE. It is shown that, although the SWITG mode may be linearly more unstable than the standard long wavelength (k{sub y}{rho}{sub s}<1) ITG mode, nonlinearly its contribution to the total thermal ion heat transport is found to be low. We interpret this as resulting from an increased zonal flow shearing effect on the SWITG mode suppression.

  8. Cosmological simulations of isotropic conduction in galaxy clusters

    SciTech Connect (OSTI)

    Smith, Britton; O'Shea, Brian W.; Voit, G. Mark; Ventimiglia, David; Skillman, Samuel W.

    2013-12-01

    Simulations of galaxy clusters have a difficult time reproducing the radial gas-property gradients and red central galaxies observed to exist in the cores of galaxy clusters. Thermal conduction has been suggested as a mechanism that can help bring simulations of cluster cores into better alignment with observations by stabilizing the feedback processes that regulate gas cooling, but this idea has not yet been well tested with cosmological numerical simulations. Here we present cosmological simulations of 10 galaxy clusters performed with five different levels of isotropic Spitzer conduction, which alters both the cores and outskirts of clusters, though not dramatically. In the cores, conduction flattens central temperature gradients, making them nearly isothermal and slightly lowering the central density, but failing to prevent a cooling catastrophe there. Conduction has little effect on temperature gradients outside of cluster cores because outward conductive heat flow tends to inflate the outer parts of the intracluster medium (ICM), instead of raising its temperature. In general, conduction tends reduce temperature inhomogeneity in the ICM, but our simulations indicate that those homogenizing effects would be extremely difficult to observe in ?5 keV clusters. Outside the virial radius, our conduction implementation lowers the gas densities and temperatures because it reduces the Mach numbers of accretion shocks. We conclude that, despite the numerous small ways in which conduction alters the structure of galaxy clusters, none of these effects are significant enough to make the efficiency of conduction easily measurable, unless its effects are more pronounced in clusters hotter than those we have simulated.

  9. Hot Pot Contoured Temperature Gradient Map

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Lane, Michael

    2013-06-28

    Temperature gradient contours derived from Oski temperature gradient hole program and from earlier published information.

  10. Hot Pot Contoured Temperature Gradient Map

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Lane, Michael

    Temperature gradient contours derived from Oski temperature gradient hole program and from earlier published information.

  11. Next-Generation LED Package Architectures Enabled by Thermally...

    Energy Savers [EERE]

    LED Package Architectures Enabled by Thermally Conductive Transparent Encapsulants Next-Generation LED Package Architectures Enabled by Thermally Conductive Transparent ...

  12. Energy in density gradient

    SciTech Connect (OSTI)

    Vranjes, J.; Kono, M.

    2015-01-15

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work, the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindrical configuration. This is of practical importance for drift wave instability in various plasmas, and, in particular, in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit volume (per second) in quiet regions in the corona. Consequently, within the life-time of a magnetic structure such energy losses can easily be compensated by the stochastic drift wave heating.

  13. Electrochemical-thermal modeling and microscale phase change for passive internal thermal management of lithium ion batteries.

    SciTech Connect (OSTI)

    Fuller, Thomas F.; Bandhauer, Todd; Garimella, Srinivas

    2012-01-01

    A fully coupled electrochemical and thermal model for lithium-ion batteries is developed to investigate the impact of different thermal management strategies on battery performance. In contrast to previous modeling efforts focused either exclusively on particle electrochemistry on the one hand or overall vehicle simulations on the other, the present work predicts local electrochemical reaction rates using temperature-dependent data on commercially available batteries designed for high rates (C/LiFePO{sub 4}) in a computationally efficient manner. Simulation results show that conventional external cooling systems for these batteries, which have a low composite thermal conductivity ({approx}1 W/m-K), cause either large temperature rises or internal temperature gradients. Thus, a novel, passive internal cooling system that uses heat removal through liquid-vapor phase change is developed. Although there have been prior investigations of phase change at the microscales, fluid flow at the conditions expected here is not well understood. A first-principles based cooling system performance model is developed and validated experimentally, and is integrated into the coupled electrochemical-thermal model for assessment of performance improvement relative to conventional thermal management strategies. The proposed cooling system passively removes heat almost isothermally with negligible thermal resistances between the heat source and cooling fluid. Thus, the minimization of peak temperatures and gradients within batteries allow increased power and energy densities unencumbered by thermal limitations.

  14. Thermal insulations using vacuum panels

    DOE Patents [OSTI]

    Glicksman, Leon R. (Lynnfield, MA); Burke, Melissa S. (Pittsburgh, PA)

    1991-07-16

    Thermal insulation vacuum panels are formed of an inner core of compressed low thermal conductivity powders enclosed by a ceramic/glass envelope evaluated to a low pressure.

  15. High-gradient compact linear accelerator

    DOE Patents [OSTI]

    Carder, B.M.

    1998-05-26

    A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

  16. Sources of stress gradients in electrodeposited Ni MEMS. (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Sources of stress gradients in electrodeposited Ni MEMS. Citation Details In-Document Search Title: Sources of stress gradients in electrodeposited Ni MEMS. The ability of future integrated metal-semiconductor micro-systems such as RF MEMS to perform highly complex functions will depend on developing freestanding metal structures that offer improved conductivity and reflectivity over polysilicon structures. For example, metal-based RF MEMS technology could replace the bulky

  17. Gradient zone boundary control in salt gradient solar ponds

    DOE Patents [OSTI]

    Hull, John R.

    1984-01-01

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  18. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, John A.; Greenwald, Shlomo

    1989-01-01

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  19. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, J.A.; Greenwald, S.

    1989-05-30

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  20. Fourier analysis of conductive heat transfer for glazed roofing materials

    SciTech Connect (OSTI)

    Roslan, Nurhana Lyana; Bahaman, Nurfaradila; Almanan, Raja Noorliyana Raja; Ismail, Razidah; Zakaria, Nor Zaini

    2014-07-10

    For low-rise buildings, roof is the most exposed surface to solar radiation. The main mode of heat transfer from outdoor via the roof is conduction. The rate of heat transfer and the thermal impact is dependent on the thermophysical properties of roofing materials. Thus, it is important to analyze the heat distribution for the various types of roofing materials. The objectives of this paper are to obtain the Fourier series for the conductive heat transfer for two types of glazed roofing materials, namely polycarbonate and polyfilled, and also to determine the relationship between the ambient temperature and the conductive heat transfer for these materials. Ambient and surface temperature data were collected from an empirical field investigation in the campus of Universiti Teknologi MARA Shah Alam. The roofing materials were installed on free-standing structures in natural ventilation. Since the temperature data are generally periodic, Fourier series and numerical harmonic analysis are applied. Based on the 24-point harmonic analysis, the eleventh order harmonics is found to generate an adequate Fourier series expansion for both glazed roofing materials. In addition, there exists a linear relationship between the ambient temperature and the conductive heat transfer for both glazed roofing materials. Based on the gradient of the graphs, lower heat transfer is indicated through polyfilled. Thus polyfilled would have a lower thermal impact compared to polycarbonate.

  1. Dielectric-Lined High-Gradient Accelerator Structure

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-04-24

    Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 dB. Experiments for studying RF high-field effects on CVD diamond samples failed to show any evidence after more than 10{sup 5} RF pulses of RF breakdown up to a tangential surface field strength of 153 MV/m; studies at higher fields were not possible due to a degradation in magnicon performance. A rebuild of the tube is underway at this writing. Computed performance for a dielectric-loaded rectangular accelerator structure (DLA) shows highly competitive properties, as compared with an existing all-metal structure. For example, comparisons were made of a DLA structure having two planar CVD diamond elements with a all-metal CERN structure HDS operating at 30 GHz. It was shown that the ratio of maximum surface electric field to accelerating field at the metal wall is only 0.35-0.4 for DLA, much smaller than the value 2.2 for HDS; and the ratio of surface magnetic field to accelerating field is 3.0 mA/V for DLA, compared with 3.45 mA/V for HDS. These values bode well for DLA in helping to avoid breakdown and to reducing pulsed surface heating and fatigue. The shunt impedance is found to be 160-175 M{Omega}/m for DLA, as compared to 99 M{Omega}/m for HDS. Conclusions are reached from this project that CVD diamond appears promising as a dielectric with a high threshold for RF breakdown, and that rectangular accelerator structures can be devised using planar CVD diamond elements that could be operated at higher acceleration gradients with low probability of RF breakdown, as compared with corresponding all-metallic structures.

  2. Variable pressure thermal insulating jacket

    DOE Patents [OSTI]

    Nelson, Paul A. (Wheaton, IL); Malecha, Richard F. (Naperville, IL); Chilenskas, Albert A. (Chicago, IL)

    1994-01-01

    A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

  3. Variable pressure thermal insulating jacket

    DOE Patents [OSTI]

    Nelson, P.A.; Malecha, R.F.; Chilenskas, A.A.

    1994-09-20

    A device for controlled insulation of a thermal device is disclosed. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communication with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket. 10 figs.

  4. The Influence of High Pressure Thermal Behavior on Friction-induced material transfer During Dry Machining of Titanium

    SciTech Connect (OSTI)

    Abdel-Aal, H. A.; El Mansori, M.

    2011-05-04

    In this paper we study failure of coated carbide tools due to thermal loading. The study emphasizes the role assumed by the thermo-physical properties of the tool material in enhancing or preventing mass attrition of the cutting elements within the tool. It is shown that within a comprehensive view of the nature of conduction in the tool zone, thermal conduction is not solely affected by temperature. Rather it is a function of the so called thermodynamic forces. These are the stress, the strain, strain rate, rate of temperature rise, and the temperature gradient. Although that within such consideration description of thermal conduction is non-linear, it is beneficial to employ such a form because it facilitates a full mechanistic understanding of thermal activation of tool wear.

  5. Microstructure changes and thermal conductivity reduction in...

    Office of Scientific and Technical Information (OSTI)

    Resource Relation: Journal Name: Journal of Nuclear Materials; Journal Volume: 545; Journal Issue: 1-3 Publisher: Elsevier Research Org: Idaho National Laboratory (INL) Sponsoring ...

  6. Continuous Processing of High Thermal Conductivity Polyethylene...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Project innovations include using massively parallel nanochannels to align gel molecular chains and arranging closely spaced nanochannels to assist in sheet formation. Because ...

  7. Continuous Processing of High Thermal Conductivity Polyethylene...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Chain orientation in drawn polymer Chain orientation in amorphous polymer Polymer microstructure 1 S. Shen, A. Henry, J. Tong, R. Zheng, and G. Chen, Nat Nano 5, (4), (2010). ...

  8. Thermal boundary conductance accumulation and spectral phonon...

    Office of Scientific and Technical Information (OSTI)

    Si and metalsapphire interfaces. Abstract not provided. Authors: Ihlefeld, Jon. ; Brown-Shaklee, Harlan James ; Cheaito, Ramez ; Gaskins, John T. ; Caplan, Matthew E. ;...

  9. Thermal boundary conductance accumulation and interfacial phonon...

    Office of Scientific and Technical Information (OSTI)

    M. ; Giri, Ashutosh ; Duda, John C. ; Szwejkowski, Chester J. ; Constantin, Costel ; Brown-Shaklee, Harlan J. ; Ihlefeld, Jon F. ; Hopkins, Patrick E. Publication Date:...

  10. Conduction cooled tube supports

    DOE Patents [OSTI]

    Worley, Arthur C. (Mt. Tabor, NJ); Becht, IV, Charles (Morristown, NJ)

    1984-01-01

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  11. CONDUCTION IN LOW MACH NUMBER FLOWS. I. LINEAR AND WEAKLY NONLINEAR REGIMES

    SciTech Connect (OSTI)

    Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Burns, Keaton J.; Oishi, Jeffrey S.; Vasil, Geoffrey M.

    2014-12-20

    Thermal conduction is an important energy transfer and damping mechanism in astrophysical flows. Fourier's law, in which the heat flux is proportional to the negative temperature gradient, leading to temperature diffusion, is a well-known empirical model of thermal conduction. However, entropy diffusion has emerged as an alternative thermal conduction model, despite not ensuring the monotonicity of entropy. This paper investigates the differences between temperature and entropy diffusion for both linear internal gravity waves and weakly nonlinear convection. In addition to simulating the two thermal conduction models with the fully compressible Navier-Stokes equations, we also study their effects in the reduced ''soundproof'' anelastic and pseudoincompressible (PI) equations. We find that in the linear and weakly nonlinear regime, temperature and entropy diffusion give quantitatively similar results, although there are some larger errors in the PI equations with temperature diffusion due to inaccuracies in the equation of state. Extrapolating our weakly nonlinear results, we speculate that differences between temperature and entropy diffusion might become more important for strongly turbulent convection.

  12. Normal Conducting CLIC Technology

    SciTech Connect (OSTI)

    Jensen, Erk

    2006-01-03

    The CLIC (Compact Linear Collider) multi-lateral study group based at CERN is studying the technology for an electron-positron linear collider with a centre-of-mass energy up to 5 TeV. In contrast to the International Linear Collider (ILC) study which has chosen to use super-conducting cavities with accelerating gradients in the range of 30-40 MV/m to obtain centre-of-mass collision energies of 0.5-1 TeV, the CLIC study aims to use a normal-conducting system based on two-beam technology with gradients of 150 MV/m. It is generally accepted that this change in technology is not only necessary but the only viable choice for a cost-effective multi-TeV collider. The CLIC study group is studying the technology issues of such a machine, and is in particular developing state-of-the-art 30 GHz molybdenum-iris accelerating structures and power extraction and transfer structures (PETS). The accelerating structure has a new geometry which includes fully-profiled RF surfaces optimised to minimize surface fields, and hybrid damping using both iris slots and radial waveguides. A newly-developed structure-optimisation procedure has been used to simultaneously balance surface fields, power flow, short and long-range transverse wakefields, RF-to-beam efficiency and the ratio of luminosity to input power. The slotted irises allow a simple structure fabrication by high-precision high-speed 3D milling of just four pieces, and an even easier bolted assembly in a vacuum chamber.

  13. Thermal Gradient Holes At Lightning Dock Geothermal Area (Cunniff...

    Open Energy Info (EERE)

    Basis Report on a phase 2 project for DOE Notes A summary of the geophysical and geotechnical data used to pick drill sites, the actual drilling, and then the results from the...

  14. Thermal Gradient Holes At Chena Area (Erkan, Et. Al., 2008) ...

    Open Energy Info (EERE)

    Holes Activity Date Usefulness useful DOE-funding Unknown Notes MULTI-STAGE DRILLING Once a hole is drilled the natural-state pressure distribution with depth is essentially...

  15. Thermal Gradient Holes At Blue Mountain Geothermal Area (Fairbank...

    Open Energy Info (EERE)

    of at least 150C for the inferred geothermal reservoir. References Brian D. Fairbank, Kim V. Niggemann (2004) Deep Blue No.1-A Slimhole Geothermal Discovery At Blue Mountain,...

  16. Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    studies, and seem to prove useful in most cases (Flexser, 1991; Goff et al., 1991; Smith and Suemnicht, 1991). Results from these studies are also summarized in Sorey et al....

  17. Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    Regime of Long Valley Caldera. Journal of Geophysical Research. 81(5):763-768. J.L. Smith,R.W. Rex. 1977. Drilling results from eastern Long Valley Caldera. () : American...

  18. Thermal Gradient Holes At Roosevelt Hot Springs Geothermal Area...

    Open Energy Info (EERE)

    References S. H. Ward, W. T. Parry, W. P. Nash, W. R. Sill, K. L. Cook, R. B. Smith, D. S. Chapman, F. H. Brown, J. A. Whelan, J. R. Bowman (1978) A Summary of the...

  19. Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al...

    Open Energy Info (EERE)

    L. Trowbridge Grose, John C. Murray, Catherine K. Skokan (1979) Results Of An Experimental Drill Hole At The Summit Of Kilauea Volcano, Hawaii Additional References Retrieved...

  20. Thermal Gradient Holes At Lake City Hot Springs Area (Warpinski...

    Open Energy Info (EERE)

    consists of a previously identified geothermal site that has been explored with both geophysics and drilling (Hedel, 1981), but has not been characterized adequately to allow...

  1. Thermal Gradient Holes At Long Valley Caldera Geothermal Area...

    Open Energy Info (EERE)

    useful DOE-funding Unknown Exploration Basis The study integrates detailed results from pump tests, fluid level monitoring, temperature logging, and fluid samplinganalysis of the...

  2. Thermal Gradient Holes At Chena Geothermal Area (Holdmann, Et...

    Open Energy Info (EERE)

    eight wells ranging in depth from 200 to 300 ft. References Gwen Holdmann, Dick Benoit, David Blackwell (2006) Integrated Geoscience Investigation and Geothermal Exploration at...

  3. Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al...

    Open Energy Info (EERE)

    waters with a minimum of 82 degrees C at depth References Lara Owens, Richard Baars, David Norman, Harold Tobin (2005) New Methods In Exploration At The Socorro Peak Kgra- A...

  4. Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski,...

    Open Energy Info (EERE)

    Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum...

  5. Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al.,...

    Open Energy Info (EERE)

    Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum...

  6. Thermal Gradient Holes At Fort Bidwell Area (Lafleur, Et Al....

    Open Energy Info (EERE)

    continue exploration when funding allows." References Joe LaFleur, Anna Carter, Karen Moore, Ben Barker, Paul Atkinson, Clay Jones, Joseph Moore, Bernold Pollard (2010) Update On...

  7. Thermal Gradient Holes At Obsidian Cliff Area (Hulen, Et Al....

    Open Energy Info (EERE)

    DOE-funding Unknown References Jeff Hulen, Denis Norton, Dennis Kaspereit, Larry Murray, Todd van de Putte, Melinda Wright (2003) Geology And A Working Conceptual Model Of...

  8. Thermal Gradient Holes At Fenton Hill HDR Geothermal Area (Purtymun...

    Open Energy Info (EERE)

    Valles caldera in order to locate an of high heat flow that would serve as a favorable test site for the HDR concept. Notes Data from these wells are report in Reiter et al....

  9. Thermal Gradient Holes At Hualalai Northwest Rift Area (Thomas...

    Open Energy Info (EERE)

    water samples taken from these wells did not provide useful geothermal data due to contamination of the well water with drilling muds References Donald M. Thomas (1 January 1986)...

  10. Thermal Gradient Holes At Lightning Dock Area (Cunniff & Bowers...

    Open Energy Info (EERE)

    Roy A. Cunniff, Roger L. Bowers (2005) Final technical report geothermal resource evaluation and definition (GRED) Program - Phase I, II and III for the Animas Valley, NM...

  11. Thermal Gradient Holes At Lightning Dock Geothermal Area (Cunniff...

    Open Energy Info (EERE)

    Roy A. Cunniff, Roger L. Bowers (2005) Final technical report geothermal resource evaluation and definition (GRED) Program - Phase I, II and III for the Animas Valley, NM...

  12. Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010)...

    Open Energy Info (EERE)

    Exploration program undertaken during Phase II of the DOE-funded Geothermal Resource Evaluation and Definitions Program Phase I (GRED III Phase II) Notes A deeper well, TG-12,...

  13. Thermal Gradient Holes At Tungsten Mountain Area (Shevenell,...

    Open Energy Info (EERE)

    Holes Activity Date Usefulness useful DOE-funding Unknown Notes Collaboration with the gold mining industry has brought two new geothermal discoveries to the attention of the...

  14. Thermal Gradient Holes At Spencer Hot Springs Area (Shevenell...

    Open Energy Info (EERE)

    Holes Activity Date Usefulness useful DOE-funding Unknown Notes Collaboration with the gold mining industry has brought two new geothermal discoveries to the attention of the...

  15. Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit...

    Open Energy Info (EERE)

    of Hot Creek Canyon where challenges such as topography, a wilderness study area, and wetlands issues will make further exploration time consuming and costly. References Dick...

  16. Thermal Gradient Holes At Hawthorne Area (Sabin, Et Al., 2010...

    Open Energy Info (EERE)

    will be installed at select sites in California and Nevada. Interim data from this campaign are already available for the Chocolate Mountains and Hawthorne. Results of these...

  17. Thermal Gradient Holes At Chocolate Mountains Area (Sabin, Et...

    Open Energy Info (EERE)

    will be installed at select sites in California and Nevada. Interim data from this campaign are already available for the Chocolate Mountains and Hawthorne. Results of these...

  18. Thermal Gradient Holes At Coso Geothermal Area (1974) | Open...

    Open Energy Info (EERE)

    Activity Date 1974 Usefulness useful DOE-funding Unknown Exploration Basis Use heat flow studies for the first time at Coso to indicate the presence or absence of abnormal heat...

  19. Thermal Gradient Holes At Northern Basin & Range Region (Pritchett...

    Open Energy Info (EERE)

    Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoreticalcomputer simulation tests of various methods on eight hypothetical 'model' basing-and-range...

  20. Thermal Gradient Holes At Walker-Lane Transitional Zone Region...

    Open Energy Info (EERE)

    Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoreticalcomputer simulation tests of various methods on eight hypothetical 'model' basing-and-range...

  1. Thermal Gradient Holes At Central Nevada Seismic Zone Region...

    Open Energy Info (EERE)

    Activity Date Usefulness useful DOE-funding Unknown Notes NOTE: These are theoreticalcomputer simulation tests of various methods on eight hypothetical 'model' basing-and-range...

  2. Thermal Gradient Holes At Nw Basin & Range Region (Pritchett...

    Open Energy Info (EERE)

    Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoreticalcomputer simulation tests of various methods on eight hypothetical 'model' basing-and-range...

  3. Thermal Gradient Holes At Lightning Dock Geothermal Area (Arnold...

    Open Energy Info (EERE)

    be drilled by AMEX, but no results were presented in this paper. References Arnold, Anderson, Donaldson, Foster, Gutjahr, Hatton, Hill, Martinez (1978) New Mexico's Energy...

  4. Thermal control structure and garment

    DOE Patents [OSTI]

    Klett, James W.; Cameron, Christopher Stan

    2012-03-13

    A flexible thermally conductive structure. The structure generally includes a plurality of thermally conductive yarns, at least some of which are at least partially disposed adjacent to an elastomeric material. Typically, at least a portion of the plurality of thermally conductive yarns is configured as a sheet. The yarns may be constructed from graphite, metal, or similar materials. The elastomeric material may be formed from urethane or silicone foam that is at least partially collapsed, or from a similar material. A thermal management garment is provided, the garment incorporating a flexible thermally conductive structure.

  5. Device for thermal transfer and power generation

    DOE Patents [OSTI]

    Weaver, Stanton Earl (Northville, NY); Arik, Mehmet (Niskayuna, NY)

    2011-04-19

    A system is provided. The system includes a device that includes top and bottom thermally conductive substrates positioned opposite to one another, wherein a top surface of the bottom thermally conductive substrate is substantially atomically flat and a thermal blocking layer disposed between the top and bottom thermally conductive substrates. The device also includes top and bottom electrodes separated from one another between the top and bottom thermally conductive substrates to define a tunneling path, wherein the top electrode is disposed on the thermal blocking layer and the bottom electrode is disposed on the bottom thermally conductive substrate.

  6. A Sensitivity Analysis of a Thin Film Conductivity Estimation...

    Office of Scientific and Technical Information (OSTI)

    ... Language: English Subject: 36 MATERIALS SCIENCE; CONVECTION; SENSITIVITY ANALYSIS; SPECIFIC HEAT; SUBSTRATES; THERMAL CONDUCTIVITY; THERMODYNAMIC PROPERTIES; THICKNESS; THIN FILMS; ...

  7. Tunable thermal link

    DOE Patents [OSTI]

    Chang, Chih-Wei; Majumdar, Arunava; Zettl, Alexander K.

    2014-07-15

    Disclosed is a device whereby the thermal conductance of a multiwalled nanostructure such as a multiwalled carbon nanotube (MWCNT) can be controllably and reversibly tuned by sliding one or more outer shells with respect to the inner core. As one example, the thermal conductance of an MWCNT dropped to 15% of the original value after extending the length of the MWCNT by 190 nm. The thermal conductivity returned when the tube was contracted. The device may comprise numbers of multiwalled nanotubes or other graphitic layers connected to a heat source and a heat drain and various means for tuning the overall thermal conductance for applications in structure heat management, heat flow in nanoscale or microscale devices and thermal logic devices.

  8. A high-pressure route to thermoelectrics with low thermal conductivity: The solid solution series AgIn{sub x}Sb{sub 1?x}Te{sub 2} (x=0.10.6)

    SciTech Connect (OSTI)

    Schrder, Thorsten; Rosenthal, Tobias; Souchay, Daniel; Petermayer, Christian; Grott, Sebastian; Scheidt, Ernst-Wilhelm; Gold, Christian; Scherer, Wolfgang; Oeckler, Oliver

    2013-10-15

    Metastable rocksalt-type phases of the solid solution series AgIn{sub x}Sb{sub 1?x}Te{sub 2} (x=0.1, 0.2, 0.4, 0.5 and 0.6) were prepared by high-pressure synthesis at 2.5 GPa and 400 C. In these structures, the coordination number of In{sup 3+} is six, in contrast to chalcopyrite ambient-pressure AgInTe{sub 2} with fourfold In{sup 3+} coordination. Transmission electron microscopy shows that real-structure phenomena and a certain degree of short-range order are present, yet not very pronounced. All three cations are statistically disordered. The high degree of disorder is probably the reason why AgIn{sub x}Sb{sub 1?x}Te{sub 2} samples with 0.4thermal conductivities with a total ?<0.5 W/K m and a lattice contribution of ?{sub ph} ?0.3 W/K m at room temperature. These are lower than those of other rocksalt-type tellurides at room temperature; e.g. the well-known thermoelectric AgSbTe{sub 2} (? ?0.6 W/K m). The highest ZT value (0.15 at 300 K) is observed for AgIn{sub 0.5}Sb{sub 0.5}Te{sub 2}, mainly due to its high Seebeck coefficient of 160 V/K. Temperature-dependent X-ray powder patterns indicate that the solid solutions are metastable at ambient pressure. At 150 C, the quaternary compounds decompose into chalcopyrite-type AgInTe{sub 2} and rocksalt-type AgSbTe{sub 2}. - Graphical abstract: Reaction scheme, temperature characteristics of the ZT value and a selected-area electron diffraction pattern (background) of AgIn{sub 0.5}Sb{sub 0.5}Te{sub 2}, which crystallizes in a rocksalt-type structure with statistical cation disorder. Display Omitted - Highlights: High-pressure synthesis yields the novel solid solution series AgIn{sub x}Sb{sub 1?x}Te{sub 2}. In contrast to AgInTe{sub 2}, the compounds are inert at ambient pressure. HRTEM shows no pronounced short-range order in the disordered NaCl-type structure. The metastable phases exhibit very low total thermal conductivities <0.5 W/K m. ZT values of 0.15 at room temperature were measured for AgIn{sub 0.5}Sb{sub 0.5}Te{sub 2}.

  9. Thermal properties of soils and soils testing

    SciTech Connect (OSTI)

    Not Available

    1981-02-17

    The thermal properties of soils are reviewed with reference to the use of soils as heat sources, heat sinks, or thermal storage. Specific heat and thermal conductivity are discussed. (ACR)

  10. Article for thermal energy storage

    DOE Patents [OSTI]

    Salyer, Ival O.

    2000-06-27

    A thermal energy storage composition is provided which is in the form of a gel. The composition includes a phase change material and silica particles, where the phase change material may comprise a linear alkyl hydrocarbon, water/urea, or water. The thermal energy storage composition has a high thermal conductivity, high thermal energy storage, and may be used in a variety of applications such as in thermal shipping containers and gel packs.

  11. Thermal protection apparatus

    DOE Patents [OSTI]

    Bennett, G.A.; Elder, M.G.; Kemme, J.E.

    1984-03-20

    The disclosure is directed to an apparatus for thermally protecting sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components such as electronics to a heat sink such as ice.

  12. Thermal protection apparatus

    DOE Patents [OSTI]

    Bennett, Gloria A. (Los Alamos, NM); Elder, Michael G. (Los Alamos, NM); Kemme, Joseph E. (Albuquerque, NM)

    1985-01-01

    An apparatus which thermally protects sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components to a heat sink such as ice.

  13. A Sensitivity Analysis of a Thin Film Conductivity Estimation Method

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Conference: A Sensitivity Analysis of a Thin Film Conductivity Estimation Method Citation Details In-Document Search Title: A Sensitivity Analysis of a Thin Film Conductivity Estimation Method An analysis method was developed for determining the thermal conductivity of a thin film on a substrate of known thermal properties using the flash diffusivity method. In order to determine the thermal conductivity of the film using this method, the volumetric heat

  14. Geothermal regime and thermal history of the Llanos Basin, Columbia

    SciTech Connect (OSTI)

    Bachu, S.; Underschultz, J.R.; Ramon, J.C.; Villegas, M.E.

    1995-01-01

    The Llanos basin is a siliciclastic foreland sub-Andean sedimentary basin located in Columbia between the Cordillera Oriental and the Guyana Precambrian shield. Data on bottom-hole temperature, lithology, porosity, and vitrinite reflectance from all 318 wells drilled in the central and southern parts of the basin were used to analyze its geothermal regime and thermal history. Average geothermal gradients in the Llanos basin decrease generally with depth and westward toward the fold and thrust belt. The geothermal regime is controlled by a moderate, generally westward-decreasing basement heat flow, by depositional and compaction factors, and, in places, by advection by formation waters. Compaction leads to increased thermal conductivity with depth, whereas westward downdip flow in deep sandstone formations may exert a cooling effect in the central-western part of the basin. Vitrinite reflectance variation with depth shows a major discontinuity at the pre-Cretaceous unconformity. Areally, vitrinite reflectance increases southwestward in Paleozoic strata and northwestward in post-Paleozoic strata. These patterns indicate that the thermal history of the basin probably includes three thermal events that led to peaks in oil generation: a Paleozoic event in the southwest, a failed Cretaceous rifting event in the west, and an early Tertiary back-arc event in the west. Rapid cooling since the last thermal event is possibly caused by subhorizontal subduction of cold oceanic lithospheric plate.

  15. Approximate error conjugation gradient minimization methods

    DOE Patents [OSTI]

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  16. 2-D Finite Element Heat Conduction

    Energy Science and Technology Software Center (OSTI)

    1989-10-30

    AYER is a finite element program which implicitly solves the general two-dimensional equation of thermal conduction for plane or axisymmetric bodies. AYER takes into account the effects of time (transient problems), in-plane anisotropic thermal conductivity, a three-dimensional velocity distribution, and interface thermal contact resistance. Geometry and material distributions are arbitrary, and input is via subroutines provided by the user. As a result, boundary conditions, material properties, velocity distributions, and internal power generation may be mademore » functions of, e.g., time, temperature, location, and heat flux.« less

  17. Modeling thermal/chemical/mechanical response of energetic materials

    SciTech Connect (OSTI)

    Baer, M.R.; Hobbs, M.L.; Gross, R.J.

    1995-07-01

    An overview of modeling at Sandia National Laboratories is presented which describes coupled thermal, chemical and mechanical response of energetic materials. This modeling addresses cookoff scenarios for safety assessment studies in systems containing energetic materials. Foundation work is discussed which establishes a method for incorporating chemistry and mechanics into multidimensional analysis. Finite element analysis offers the capabilities to simultaneously resolve reactive heat transfer and structural mechanics in complex geometries. Nonlinear conduction heat transfer, with multiple step finite-rate chemistry, is resolved using a thermal finite element code. Rate equations are solved element-by-element using a modified matrix-free stiff solver This finite element software was developed for the simulation of systems requiring large numbers of finite elements. An iterative implicit scheme, based on the conjugate gradient method, is used and a hemi-cube algorithm is employed for the determination of view factors in surface-to-surface radiation transfer The critical link between the reactive heat transfer and mechanics is the introduction of an appropriate constitutive material model providing a stress-strain relationship for quasi-static mechanics analysis. This model is formally derived from bubble nucleation theory, and parameter variations of critical model parameters indicate that a small degree of decomposition leads to significant mechanical response. Coupled thermal/chemical/mechanical analysis is presented which simulates experiments designed to probe cookoff thermal-mechanical response of energetic materials.

  18. Discrete Modeling of Early-Life Thermal Fracture in Ceramic Nuclear Fuel

    SciTech Connect (OSTI)

    Spencer, B. W.; Huang, H.; Dolbow, J. E.; Hales, J. D.

    2015-03-01

    Fracturing of ceramic fuel pellets heavily influences performance of light water reactor (LWR) fuel. Early in the life of fuel, starting with the initial power ramp, large thermal gradients cause high tensile hoop and axial stresses in the outer region of the fuel pellets, resulting in the formation of radial and axial cracks. Circumferential cracks form due to thermal gradients that occur when the power is ramped down. These thermal cracks cause the fuel to expand radially, closing the pellet/cladding gap and enhancing the thermal conductance across that gap, while decreasing the effective conductivity of the fuel in directions normal to the cracking. At lower length scales, formation of microcracks is an important contributor to the decrease in bulk thermal conductivity that occurs over the life of the fuel as the burnup increases. Because of the important effects that fracture has on fuel performance, a realistic, physically based fracture modeling capability is essential to predict fuel behavior in a wide variety of normal and abnormal conditions. Modeling fracture within the context of the finite element method, which is based on continuous interpolations of solution variables, has always been challenging because fracture is an inherently discontinuous phenomenon. Work is underway at Idaho National Laboratory to apply two modeling techniques model fracture as a discrete displacement discontinuity to nuclear fuel: The extended finite element method (XFEM), and discrete element method (DEM). XFEM is based on the standard finite element method, but with enhancements to represent discontinuous behavior. DEM represents a solid as a network of particles connected by bonds, which can arbitrarily fail if a fracture criterion is reached. This paper presents initial results applying the aforementioned techniques to model fuel fracturing. This work has initially focused on early life behavior of ceramic LWR fuel. A coupled thermal-mechanical XFEM method that includes discontinuities in both temperature and displacement fields at crack locations has been developed and is being applied to thermal fracture of LWR fuel. A DEM model of coupled heat conduction and solid mechanics has been developed and used to simulate random initiation and propagation of thermally driven cracks during initial power cycles. This DEM model predicts the formation of realistic radial cracking patterns during power rise and circumferential cracks as power is ramped down. These initial results are very encouraging, and these techniques are expected to provide improved understanding of fuel behavior in a wide variety of conditions.

  19. Effect of the field gradient of an intense electromagnetic beam on electrons and atoms

    SciTech Connect (OSTI)

    Askaryan, G.A.

    1991-01-02

    It is demonstrated that the transverse inhomogeneity of a strong electromagnetic ray can exert a strong effect on electrons and atoms of a medium. Thus, if the wave frequency exceeds the proper frequency the electron oscillations (in a plasma or in atoms), the electrons or atoms will be forced-out of the ray field. At sub-resonance frequencies the particles will be pulled in, the force being especially large at resonance. As a result of this effect a rarefication or compression may occur in the ray or in the focus of the radiation; moreover the pressure gradient near the hole connecting the evacuated vessel with the atmosphere may be maintained and a channel conducting charged particles may be created in the medium. It is mentioned that a strong thermal, ionizing and separating effect of ray on the medium can be used for setting up wave guide conditions of propagation and for eliminating divergency of the ray (self-focusing). It is noted that hollow rays may ensure directed flow and ejection of the plasma along the ray axis for plasma transport and creation of plasma current conductors. The possibilities of acceleration and heating of plasma electrons by a modulated ray are indicated.

  20. Thermal ignition combustion system

    DOE Patents [OSTI]

    Kamo, Roy (Columbus, IN); Kakwani, Ramesh M. (Columbus, IN); Valdmanis, Edgars (Columbus, IN); Woods, Melvins E. (Columbus, IN)

    1988-01-01

    The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m.degree. C. and a specific heat greater than 480 J/kg.degree. C. with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber.

  1. Thermal ignition combustion system

    DOE Patents [OSTI]

    Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

    1988-04-19

    The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

  2. Separation of carbon nanotubes in density gradients

    DOE Patents [OSTI]

    Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

    2010-02-16

    The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

  3. Separation of carbon nanotubes in density gradients

    DOE Patents [OSTI]

    Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

    2012-02-07

    The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

  4. A Sensitivity Analysis of a Thin Film Conductivity Estimation Method

    SciTech Connect (OSTI)

    McMasters, Robert L; Dinwiddie, Ralph Barton

    2010-01-01

    An analysis method was developed for determining the thermal conductivity of a thin film on a substrate of known thermal properties using the flash diffusivity method. In order to determine the thermal conductivity of the film using this method, the volumetric heat capacity of the film must be known, as determined in a separate experiment. Additionally, the thermal properties of the substrate must be known, including conductivity and volumetric heat capacity. The ideal conditions for the experiment are a low conductivity film adhered to a higher conductivity substrate. As the film becomes thinner with respect to the substrate or, as the conductivity of the film approaches that of the substrate, the estimation of thermal conductivity of the film becomes more difficult. The present research examines the effect of inaccuracies in the known parameters on the estimation of the parameter of interest, the thermal conductivity of the film. As such, perturbations are introduced into the other parameters in the experiment, which are assumed to be known, to find the effect on the estimated thermal conductivity of the film. A baseline case is established with the following parameters: Substrate thermal conductivity 1.0 W/m-K Substrate volumetric heat capacity 106 J/m3-K Substrate thickness 0.8 mm Film thickness 0.2 mm Film volumetric heat capacity 106 J/m3-K Film thermal conductivity 0.01 W/m-K Convection coefficient 20 W/m2-K Magnitude of heat absorbed during the flash 1000 J/m2 Each of these parameters, with the exception of film thermal conductivity, the parameter of interest, is varied from its baseline value, in succession, and placed into a synthetic experimental data file. Each of these data files is individually analyzed by the program to determine the effect on the estimated film conductivity, thus quantifying the vulnerability of the method to measurement errors.

  5. Proton conducting ceramic membranes for hydrogen separation

    DOE Patents [OSTI]

    Elangovan, S. (South Jordan, UT); Nair, Balakrishnan G. (Sandy, UT); Small, Troy (Midvale, UT); Heck, Brian (Salt Lake City, UT)

    2011-09-06

    A multi-phase proton conducting material comprising a proton-conducting ceramic phase and a stabilizing ceramic phase. Under the presence of a partial pressure gradient of hydrogen across the membrane or under the influence of an electrical potential, a membrane fabricated with this material selectively transports hydrogen ions through the proton conducting phase, which results in ultrahigh purity hydrogen permeation through the membrane. The stabilizing ceramic phase may be substantially structurally and chemically identical to at least one product of a reaction between the proton conducting phase and at least one expected gas under operating conditions of a membrane fabricated using the material. In a barium cerate-based proton conducting membrane, one stabilizing phase is ceria.

  6. Design and calibration of a test facility for MLI thermal performance measurements below 80K

    SciTech Connect (OSTI)

    Boroski, W.; Kunzelman, R.; Ruschman, M.; Schoo, C.

    1992-04-01

    The design geometry of the SSC dipole cryostat includes active thermal radiation shields operating at 80K and 20K respectively. Extensive measurements conducted in a Heat Leak Test Facility (HLTF) have been used to evaluate the thermal performance of candidate multilayer insulation (MLI) systems for the 80K thermal shield, with the present system design based upon those measurement results. With the 80K MLI geometry established, efforts have focused on measuring the performance of MLI systems near 20K. A redesign of the HLTF has produced a measurement facility capable of conducting measurements with the warm boundary fixed at 80K and the cold boundary variable from 10K to 50K. Removing the 80K shield permits measurements with a warm boundary at 300K. The 80K boundary consists of a copper shield thermally anchored to a liquid nitrogen reservoir. The cold boundary consists of a copper anchor plate whose temperature is varied through boil-off gas from a 500 liter helium supply dewar. A transfer line heat exchanger supplies the boil-off gas to the anchor plate at a constant and controlled rate. The gas, which serves as cooling gas, is routed through a copper cooling tube soldered into the anchor plate. Varying the cooling gas flow rate varies the amount of refrigeration supplied to the anchor plate, thereby determining the plate temperature. A resistance heater installed on the anchor plate is regulated by a cryogenic temperature controller to provide final temperature control. Heat leak values are measured using a heatmeter which senses heat flow as a temperature gradient across a fixed thermal impedance. Since the thermal conductivity of the thermal impedance changes with temperature, the heatmeter is calibrated at key cold boundary temperatures. Thus, the system is capable of obtaining measurement data under a variety of system conditions. 7 refs.

  7. An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear

    SciTech Connect (OSTI)

    Peterson, J. L.; Hammet, G. W.; Mikkelsen, D. R.; Yuh, H. Y.; Candy, J.; Guttenfelder, W.; Kaye, S. M.; LeBlanc, B.

    2011-05-11

    The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is non- linearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.

  8. Thermal performance measurements of a 100 percent polyester MLI (multilayer insulation) system for the Superconducting Super Collider

    SciTech Connect (OSTI)

    Gonczy, J.D.; Boroski, W.N.; Niemann, R.C.

    1989-09-01

    The plastic materials used in the multilayer insulation (MLI) blankets of the superconducting magnets of the Superconducting Super Collider (SSC) are comprised entirely of polyesters. This paper reports on tests conducted in three separate experimental blanket arrangements. The tests explore the thermal performance of two candidate blanket joint configurations each employing a variation of a stepped-butted joint nested between sewn blanket seams. The results from the joint configurations are compared to measurements made describing the thermal performance of the basic blanket materials as tested in an ideal joint configuration. Twenty foil sensors were incorporated within each test blanket to measure interstitial layer and joint layer temperatures. Heat flux and thermal gradients are reported for high and degraded insulating vacuums, and during transient and steady state conditions. In complement with this paper is an associate paper bearing the same title head but with the title extension Part 1: Instrumentation and experimental preparation (300K-80K)'. 5 refs., 8 figs., 2 tabs.

  9. Ion temperature gradient driven turbulence with strong trapped...

    Office of Scientific and Technical Information (OSTI)

    Ion temperature gradient driven turbulence with strong trapped ion resonance Citation Details In-Document Search Title: Ion temperature gradient driven turbulence with strong ...

  10. Edge Temperature Gradient as Intrinsic Rotation Drive in Alcator...

    Office of Scientific and Technical Information (OSTI)

    Edge Temperature Gradient as Intrinsic Rotation Drive in Alcator C -Mod Tokamak Plasmas Citation Details In-Document Search Title: Edge Temperature Gradient as Intrinsic Rotation ...

  11. Thermal Effusivity Tomography from Pulsed Thermal Imaging

    Energy Science and Technology Software Center (OSTI)

    2006-12-01

    The software program generates 3D volume distribution of thermal effusivity within a test material from one-sided pulsed thermal imaging data. Thsi is the first software capable of accurate, fast and automated thermal tomographic imaging of inhomogeneous materials to produce 3D images similar to those obtained from 3D X-ray CT (all previous thermal-imaging software can only produce 2D results). Because thermal effusivity is an intrisic material property that is related to material constituent, density, conductivity, etc.,more » quantitative imaging of effusivity allowed direct visualization of material's internal constituent/structure and damage distributions, thereby potentially leading to quantitative prediction of other material properties such as strength. I can be therefre be used for 3D imaging of material structure in fundamental material studies, nondestructive characterization of defects/flaws in structural engineering components, health monitoring of material damage and degradation during service, and medical imaging and diagnostics. This technology is one-sided, non contact and sensitive to material's thermal property and discontinuity. One major advantage of this tomographic technology over x-ray CT and ultrasounds is its natural efficiency for 3D imaging of the volume under a large surface area. This software is implemented with a method for thermal computed tomography of thermal effusivity from one-sided pulsed thermal imaging (or thermography) data. The method is based on several solutions of the governing heat transfer equation under pulsed thermography test condition. In particular, it consists of three components. 1) It utilized the thermal effusivity as the imaging parameter to construct the 3D image. 2) It established a relationship between the space (depth) and the time, because thermography data are in the time domain. 3) It incorporated a deconvolution algorithm to solve the depth porfile of the material thermal effusivity from the measured (temporal) surface temperature data. The predicted effusivity is a direct function of depth, not an average or convolved parameter, so it is an accurate (and more sensitive) representation of local property along depth.« less

  12. Salinity gradient solar pond technology applied to potash solution mining

    SciTech Connect (OSTI)

    Martell, J.A.; Aimone-Martin, C.T.

    2000-06-12

    A solution mining facility at the Eddy Potash Mine, Eddy County, New Mexico has been proposed that will utilize salinity gradient solar pond (SGSP) technology to supply industrial process thermal energy. The process will include underground dissolution of potassium chloride (KCl) from pillars and other reserves remaining after completion of primary room and pillar mining using recirculating solutions heated in the SGSP. Production of KCl will involve cold crystallization followed by a cooling pond stage, with the spent brine being recirculated in a closed loop back to the SGSP for reheating. This research uses SGSP as a renewable, clean energy source to optimize the entire mining process, minimize environmental wastes, provide a safe, more economical extraction process and reduce the need for conventional processing by crushing, grinding and flotation. The applications of SGSP technology will not only save energy in the extraction and beneficiation processes, but also will produce excess energy available for power generation, desalination, and auxiliary structure heating.

  13. Nanoscale thermal transport. II. 2003-2012 (Journal Article)...

    Office of Scientific and Technical Information (OSTI)

    thermal conductivity of a thin layer with micron-scale ... Department of Materials Science and Engineering and the ... CONDUCTIVITY; THIN FILMS Word Cloud More Like This ...

  14. Thermal Properties Measurement Report

    SciTech Connect (OSTI)

    Carmack, Jon; Braase, Lori; Papesch, Cynthia; Hurley, David; Tonks, Michael; Zhang, Yongfeng; Gofryk, Krzysztof; Harp, Jason; Fielding, Randy; Knight, Collin; Meyer, Mitch

    2015-08-01

    The Thermal Properties Measurement Report summarizes the research, development, installation, and initial use of significant experimental thermal property characterization capabilities at the INL in FY 2015. These new capabilities were used to characterize a U3Si2 (candidate Accident Tolerant) fuel sample fabricated at the INL. The ability to perform measurements at various length scales are important and provide additional data that is not currently in the literature. However, the real value of the data will be in accomplishing a phenomenological understanding of the thermal conductivity in fuels and the ties to predictive modeling. Thus, the MARMOT advanced modeling and simulation capability was utilized to illustrate how the microstructural data can be modeled and compared with bulk characterization data. A scientific method was established for thermal property measurement capability on irradiated nuclear fuel samples, which will be installed in the Irradiated Material Characterization Laboratory (IMCL).

  15. High-pressure liquid chromatographic gradient mixer

    DOE Patents [OSTI]

    Daughton, C.G.; Sakaji, R.H.

    1982-09-08

    A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

  16. High pressure liquid chromatographic gradient mixer

    DOE Patents [OSTI]

    Daughton, Christian G.; Sakaji, Richard H.

    1985-01-01

    A gradient mixer which effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum "band-broadening".

  17. 17 GHz High Gradient Accelerator Research

    SciTech Connect (OSTI)

    Temkin, Richard J.; Shapiro, Michael A.

    2013-07-10

    This is a report on the MIT High Gradient Accelerator Research program which has included: Operation of the 17 GHz, 25 MeV MIT/Haimson Research Corp. electron accelerator at MIT, the highest frequency, stand-alone accelerator in the world; collaboration with members of the US High Gradient Collaboration, including the design and test of novel structures at SLAC at 11.4 GHz; the design, construction and testing of photonic bandgap structures, including metallic and dielectric structures; the investigation of the wakefields in novel structures; and the training of the next generation of graduate students and postdoctoral associates in accelerator physics.

  18. Multi-gradient drilling method and system

    DOE Patents [OSTI]

    Maurer, William C. (Houston, TX); Medley, Jr., George H. (Spring, TX); McDonald, William J. (Houston, TX)

    2003-01-01

    A multi-gradient system for drilling a well bore from a surface location into a seabed includes an injector for injecting buoyant substantially incompressible articles into a column of drilling fluid associated with the well bore. Preferably, the substantially incompressible articles comprises hollow substantially spherical bodies.

  19. Developing new high energy gradient concentration cathode material |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy new high energy gradient concentration cathode material Developing new high energy gradient concentration cathode material 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon esp_10_amine.pdf More Documents & Publications New High Energy Gradient Concentration Cathode Material New High Energy Gradient Concentration Cathode Material New High Energy Gradient

  20. Turbulent electron transport in edge pedestal by electron temperature gradient turbulence

    SciTech Connect (OSTI)

    Singh, R.; Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 ; Jhang, Hogun; Diamond, P. H.; CMTFO and CASS, University of California, San Diego 92093-0424, California

    2013-11-15

    We present a model for turbulent electron thermal transport at the edge pedestal in high (H)-mode plasmas based on electron temperature gradient (ETG) turbulence. A quasi-linear analysis of electrostatic toroidal ETG modes shows that both turbulent electron thermal diffusivity and hyper-resistivity exhibits the Ohkawa scaling in which the radial correlation length of turbulence becomes the order of electron skin depth. Combination of the Ohkawa scales and the plasma current dependence results in a novel confinement scaling inside the pedestal region. It is also shown that ETG turbulence induces a thermoelectric pinch, which may accelerate the density pedestal formation.

  1. Gradient zone-boundary control in salt-gradient solar ponds

    DOE Patents [OSTI]

    Hull, J.R.

    1982-09-29

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  2. Code of Conduct

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    About » Leadership, Governance » Ethics, Accountability, Contract » Code of Conduct Code of Conduct Helping employees recognize and resolve the ethics and compliance issues that may arise in their daily work. Contact Ethics and Compliance Group (505) 667-7506 Email Code of Conduct LANL is committed to operating in accordance with the highest standards of ethics and compliance and with its core values of service to our nation, ethical conduct and personal accountability, excellence in our

  3. Laser window with annular grooves for thermal isolation

    DOE Patents [OSTI]

    Warner, B.E.; Horton, J.A.; Alger, T.W.

    1983-07-13

    A laser window or other optical element which is thermally loaded, heats up and causes optical distortions because of temperature gradients between the center and the edge. A number of annular grooves, one to three or more, are formed in the element between a central portion and edge portion, producing a web portion which concentrates the thermal gradient and thermally isolates the central portion from the edge portion, producing a uniform temperature profile across the central portion and therefore reduce the optical distortions. The grooves are narrow and closely spaced with respect to the thickness of the element, and successive grooves are formed from alternate sides of the element.

  4. Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

    SciTech Connect (OSTI)

    Newmark, R. L.; Kasameyer, P. W.; Younker, L. W.

    1987-01-01

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.

  5. Design and calibration of a test facility for MLI thermal performance measurements below 80K. [Multilayer insulation (MLI)

    SciTech Connect (OSTI)

    Boroski, W.; Kunzelman, R.; Ruschman, M.; Schoo, C.

    1992-04-01

    The design geometry of the SSC dipole cryostat includes active thermal radiation shields operating at 80K and 20K respectively. Extensive measurements conducted in a Heat Leak Test Facility (HLTF) have been used to evaluate the thermal performance of candidate multilayer insulation (MLI) systems for the 80K thermal shield, with the present system design based upon those measurement results. With the 80K MLI geometry established, efforts have focused on measuring the performance of MLI systems near 20K. A redesign of the HLTF has produced a measurement facility capable of conducting measurements with the warm boundary fixed at 80K and the cold boundary variable from 10K to 50K. Removing the 80K shield permits measurements with a warm boundary at 300K. The 80K boundary consists of a copper shield thermally anchored to a liquid nitrogen reservoir. The cold boundary consists of a copper anchor plate whose temperature is varied through boil-off gas from a 500 liter helium supply dewar. A transfer line heat exchanger supplies the boil-off gas to the anchor plate at a constant and controlled rate. The gas, which serves as cooling gas, is routed through a copper cooling tube soldered into the anchor plate. Varying the cooling gas flow rate varies the amount of refrigeration supplied to the anchor plate, thereby determining the plate temperature. A resistance heater installed on the anchor plate is regulated by a cryogenic temperature controller to provide final temperature control. Heat leak values are measured using a heatmeter which senses heat flow as a temperature gradient across a fixed thermal impedance. Since the thermal conductivity of the thermal impedance changes with temperature, the heatmeter is calibrated at key cold boundary temperatures. Thus, the system is capable of obtaining measurement data under a variety of system conditions. 7 refs.

  6. Electrically conductive composite material

    DOE Patents [OSTI]

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  7. Electrically conductive composite material

    DOE Patents [OSTI]

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  8. Electrically conductive composite material

    DOE Patents [OSTI]

    Clough, Roger L. (Albuquerque, NM); Sylwester, Alan P. (Albuquerque, NM)

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  9. Automated apparatus for producing gradient gels

    DOE Patents [OSTI]

    Anderson, N.L.

    1983-11-10

    Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.

  10. Automated apparatus for producing gradient gels

    DOE Patents [OSTI]

    Anderson, Norman L. (Clarendon Hills, IL)

    1986-01-01

    Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.

  11. Thermal insulated glazing unit

    DOE Patents [OSTI]

    Selkowitz, S.E.; Arasteh, D.K.; Hartmann, J.L.

    1988-04-05

    An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas. 2 figs.

  12. Thermal insulated glazing unit

    DOE Patents [OSTI]

    Selkowitz, Stephen E. (Piedmont, CA); Arasteh, Dariush K. (Oakland, CA); Hartmann, John L. (Seattle, WA)

    1991-01-01

    An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas.

  13. High gradient accelerators for linear light sources

    SciTech Connect (OSTI)

    Barletta, W.A.

    1988-09-26

    Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.

  14. Nanotubes as Robust Thermal Conductors - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Advanced Materials Advanced Materials Find More Like This Return to Search Nanotubes as Robust Thermal Conductors Lawrence Berkeley National Laboratory Contact LBL About This Technology Technology Marketing SummaryMultiwall nanotubes of carbon (CNT) and of boron nitride (BNNT) have a very high thermal conductance at room temperature. Their twin properties of high thermal conductivity along the axial direction and poor thermal conductivity in the radial direction provide an excellent heat

  15. High conductance surge cable

    DOE Patents [OSTI]

    Murray, Matthew M. (Espanola, NM); Wilfong, Dennis H. (Brooksville, FL); Lomax, Ralph E. (Santa Fe, NM)

    1998-01-01

    An electrical cable for connecting transient voltage surge suppressers to ectrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation.

  16. High conductance surge cable

    DOE Patents [OSTI]

    Murray, M.M.; Wilfong, D.H.; Lomax, R.E.

    1998-12-08

    An electrical cable for connecting transient voltage surge suppressors to electrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation. 6 figs.

  17. Electrically conductive cellulose composite

    DOE Patents [OSTI]

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  18. NREL: Transportation Research - Vehicle Thermal Management Facilities

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Vehicle Thermal Management Facilities Image of a building with two semi truck cabs in front of it. The VTIF is used for thermal testing of every class of on-road vehicle. Photo by Dennis Schroeder, NREL The National Renewable Energy Laboratory (NREL) uses research and testing facilities to develop advanced thermal management technologies for vehicles. Vehicle Testing and Integration Facility The Vehicle Testing and Integration Facility features a test pad to conduct vehicle thermal soak testing

  19. Thermomechanical measurements on thermal microactuators. (Technical Report)

    Office of Scientific and Technical Information (OSTI)

    | SciTech Connect Technical Report: Thermomechanical measurements on thermal microactuators. Citation Details In-Document Search Title: Thermomechanical measurements on thermal microactuators. Due to the coupling of thermal and mechanical behaviors at small scales, a Campaign 6 project was created to investigate thermomechanical phenomena in microsystems. This report documents experimental measurements conducted under the auspices of this project. Since thermal and mechanical measurements

  20. Thermally actuated thermionic switch

    DOE Patents [OSTI]

    Barrus, Donald M.; Shires, Charles D.

    1988-01-01

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  1. Thermally actuated thermionic switch

    DOE Patents [OSTI]

    Barrus, D.M.; Shires, C.D.

    1982-09-30

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  2. Evidence of ion mixing increasing the thermal boundary conductance...

    Office of Scientific and Technical Information (OSTI)

    Authors: Hattar, Khalid Mikhiel ; Beechem Iii, Thomas Edwin ; Ihlefeld, Jon F. ; Biedermann, Laura Butler ; Piekos, Edward Stanley ; Medlin, Douglas L. 1 ; Gorham, Caroline S. ; ...

  3. Thermal Conductivity Measurements of Silicon Thin Films with...

    Office of Scientific and Technical Information (OSTI)

    Nanoscale Perforations. Abstract not provided. Authors: Harris, Charles Thomas ; Kim, Bongsang ; Reinke, Charles M. ; Hopkins, Patrick Edward ; Olsson, Roy H., ; El-Kady,...

  4. THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS

    Office of Scientific and Technical Information (OSTI)

    and uti1 ization of geothermal energy, petroleum recovery, desalination of sea water, and other energy systems involving water containing dissolved salts. brines contain a...

  5. Continuous Processing of High Thermal Conductivity Fibers and...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    due to the C-C bond In bulk polymers, however, due to entanglements and ... PATENT PENDING Technical Approach There are no commercially available pure polymers ...

  6. Thermally Conductive Organic Dielectrics for Power Electronics and Electric Motors

    Broader source: Energy.gov [DOE]

    2013 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

  7. T I ENHANCING THERMAL CONDUCTIVITY OF FLUIDS WITH NANOPARTICLES...

    Office of Scientific and Technical Information (OSTI)

    ... of copper at room temperature is 700 times greater ... since Maxwell's theoretical work was published more than 100 ... the ratio of the surface area to volume of the particle. ...

  8. First-principles prediction of phononic thermal conductivity...

    Office of Scientific and Technical Information (OSTI)

    Ronggui, E-mail: Ronggui.Yang@Colorado.Edu 1 + Show Author Affiliations Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309 (United States)...

  9. The Thermal Conductivity of Rocks and Its Dependence Upon Temperature...

    Open Energy Info (EERE)

    unavailable. Authors F. Birch and H. Clark Published Journal American Journal of Science, 1940 DOI Not Provided Check for DOI availability: http:crossref.org Online...

  10. Size effects in the thermal conductivity of gallium oxide (?...

    Office of Scientific and Technical Information (OSTI)

    2Osub 3 grown via this technique (8.8 3.4 W msup -1 Ksup -1) and large mean free paths compared to typical gate dielectrics commonly used in GaN device contacts. By...

  11. High Thermal Conductivity Polymer Composites for Low-Cost Heat...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    future heat exchanger development. (1 year project - ... available state of the art) Enable replacement of ... transfer UTRC Innovation Process CURRENT ...

  12. Thermal conductivity and diffusion-mediated localization in Fe1...

    Office of Scientific and Technical Information (OSTI)

    Additional Journal Information: Journal Volume: 84; Journal Issue: 22; Journal ID: ISSN 1098-0121 Publisher: American Physical Society Sponsoring Org: USDOE Country of...

  13. An Analytical Study Of A 2-Layer Transient Thermal Conduction...

    Open Energy Info (EERE)

    (e.g., where there is a shallow water table or a thin soil layer). Authors T. H. Larson and A. T. Hsui Published Journal Geophysics, 1992 DOI Not Provided Check for DOI...

  14. Thermal Conductivity in Nanocrystalline Ceria Thin Films (Journal...

    Office of Scientific and Technical Information (OSTI)

    Authors: Marat Khafizov ; In-Wook Park ; Aleksandr Chernatynskiy ; Lingfeng He ; Jianliang Lin ; John J. Moore ; David Swank ; Thomas Lillo ; Simon R. Phillpot ; Anter El-Azab ; ...

  15. Electrically conductive diamond electrodes

    DOE Patents [OSTI]

    Swain, Greg (East Lansing, MI); Fischer, Anne (Arlington, VA),; Bennett, Jason (Lansing, MI); Lowe, Michael (Holt, MI)

    2009-05-19

    An electrically conductive diamond electrode and process for preparation thereof is described. The electrode comprises diamond particles coated with electrically conductive doped diamond preferably by chemical vapor deposition which are held together with a binder. The electrodes are useful for oxidation reduction in gas, such as hydrogen generation by electrolysis.

  16. Conductive fabric seal

    DOE Patents [OSTI]

    Livesay, Ronald Jason; Mason, Brandon William; Kuhn, Michael Joseph; Rowe, Nathan Carl

    2015-10-13

    Disclosed are several examples of a system and method for detecting if an article is being tampered with. Included is a covering made of a substrate that is coated with a layer of an electrically conductive material that forms an electrically conductive surface having an electrical resistance. The covering is configured to at least partially encapsulate the article such that the article cannot be tampered with, without modifying the electrical resistance of the electrically conductive surface of the covering. A sensing device is affixed to the electrically conductive surface of the covering and the sensing device monitors the condition of the covering by producing a signal that is indicative of the electrical resistance of the electrically conductive surface of the covering. A measured electrical resistance that differs from a nominal electrical resistance is indicative of a covering that is being tampered with and an alert is communicated to an observer.

  17. Shallow drilling in the Salton Sea region: The thermal anomaly

    SciTech Connect (OSTI)

    Newmark, R.L.; Kasameyer, P.W.; Younker, L.W.

    1988-11-10

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The central thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 /sup 0/C/m) to extreme (0.83 /sup 0/C/m) in only 2.4 km. The heat flow in the central part of the anomaly is greater than 600 mW/m/sup 2/ and in the two local anomalies exceeds 1200 mW/m/sup 2/. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes.

  18. Heat transmission between a profiled nanowire and a thermal bath

    SciTech Connect (OSTI)

    Blanc, Christophe; Heron, Jean-Savin; Fournier, Thierry; Bourgeois, Olivier

    2014-07-28

    Thermal transport through profiled and abrupt contacts between a nanowire and a reservoir has been investigated by thermal conductance measurements. It is demonstrated that above 1?K the transmission coefficients are identical between abrupt and profiled junctions. This shows that the thermal transport is principally governed by the nanowire itself rather than by the resistance of the thermal contact. These results are perfectly compatible with the previous theoretical models. The thermal conductance measured at sub-Kelvin temperatures is discussed in relation to the universal value of the quantum of thermal conductance.

  19. Thermal to electricity conversion using thermal magnetic properties

    DOE Patents [OSTI]

    West, Phillip B [Idaho Falls, ID; Svoboda, John [Idaho Falls, ID

    2010-04-27

    A system for the generation of Electricity from Thermal Energy using the thermal magnetic properties of a Ferromagnetic, Electrically Conductive Material (FECM) in one or more Magnetic Fields. A FECM is exposed to one or more Magnetic Fields. Thermal Energy is applied to a portion of the FECM heating the FECM above its Curie Point. The FECM, now partially paramagnetic, moves under the force of the one or more Magnetic Fields. The movement of the FECM induces an electrical current through the FECM, generating Electricity.

  20. Electrically conductive material

    DOE Patents [OSTI]

    Singh, Jitendra P. (Bollingbrook, IL); Bosak, Andrea L. (Burnam, IL); McPheeters, Charles C. (Woodridge, IL); Dees, Dennis W. (Woodridge, IL)

    1993-01-01

    An electrically conductive material for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO.sub.2 as a matrix and 6-19 wt. % monoclinic ZrO.sub.2 formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO.sub.2 as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns.

  1. Conductive open frameworks

    DOE Patents [OSTI]

    Yaghi, Omar M.; Wan, Shun; Doonan, Christian J.; Wang, Bo; Deng, Hexiang

    2016-02-23

    The disclosure relates generally to materials that comprise conductive covalent organic frameworks. The disclosure also relates to materials that are useful to store and separate gas molecules and sensors.

  2. Conducting fiber compression tester

    DOE Patents [OSTI]

    DeTeresa, Steven J. (Livermore, CA)

    1990-01-01

    The invention measures the resistance across a conductive fiber attached to a substrate place under a compressive load to determine the amount of compression needed to cause the fiber to fail.

  3. Electrically conductive material

    DOE Patents [OSTI]

    Singh, J.P.; Bosak, A.L.; McPheeters, C.C.; Dees, D.W.

    1993-09-07

    An electrically conductive material is described for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO[sub 2] as a matrix and 6-19 wt. % monoclinic ZrO[sub 2] formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO[sub 2] as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns. 8 figures.

  4. Conduct of Operations

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2010-06-29

    This Order defines the requirements for establishing and implementing Conduct of Operations Programs at Department of Energy (DOE), including National Nuclear Security Administration (NNSA), facilities and projects. Cancels DOE O 5480.19. Admin Chg 1, 6-25-13

  5. Conduct of Operations

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2010-06-29

    This Order defines the requirements for establishing and implementing Conduct of Operations Programs at Department of Energy (DOE), including National Nuclear Security Administration (NNSA), facilities and projects. Admin Chg 2, dated 12-3-14, supersedes Admin Chg 1.

  6. JLF Conduct of Operations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    JLF Conduct of Operations The Conduct of Operations is a set of procedures and guidelines that are put in place to ensure operational safety and security for users and staff. The Target Areas contain a variety of potentially hazardous ultra-violet, visible and infrared lasers. Due to the complexity and scale of the laser beam paths, some beams are not enclosed. Accordingly, reliance is placed on engineering and administrative controls, and the proper use of laser protective eyewear. Other

  7. Modeling of Propagation of Interacting Cracks Under Hydraulic Pressure Gradient

    SciTech Connect (OSTI)

    Huang, Hai; Mattson, Earl Douglas; Podgorney, Robert Karl

    2015-04-01

    A robust and reliable numerical model for fracture initiation and propagation, which includes the interactions among propagating fractures and the coupling between deformation, fracturing and fluid flow in fracture apertures and in the permeable rock matrix, would be an important tool for developing a better understanding of fracturing behaviors of crystalline brittle rocks driven by thermal and (or) hydraulic pressure gradients. In this paper, we present a physics-based hydraulic fracturing simulator based on coupling a quasi-static discrete element model (DEM) for deformation and fracturing with conjugate lattice network flow model for fluid flow in both fractures and porous matrix. Fracturing is represented explicitly by removing broken bonds from the network to represent microcracks. Initiation of new microfractures and growth and coalescence of the microcracks leads to the formation of macroscopic fractures when external and/or internal loads are applied. The coupled DEM-network flow model reproduces realistic growth pattern of hydraulic fractures. In particular, simulation results of perforated horizontal wellbore clearly demonstrate that elastic interactions among multiple propagating fractures, fluid viscosity, strong coupling between fluid pressure fluctuations within fractures and fracturing, and lower length scale heterogeneities, collectively lead to complicated fracturing patterns.

  8. Exploration geothermal gradient drilling, Platanares, Honduras, Central America

    SciTech Connect (OSTI)

    Goff, S.J.; Laughlin, A.W.; Ruefenacht, H.D.; Goff, F.E.; Heiken, G.; Ramos, N.

    1988-01-01

    This paper is a review and summary of the core drilling operations component of the Honduras Geothermal Resource Development Project at the Platanares geothermal prospect in Honduras, Central America. Three intermediate depth (428 to 679 m) coreholes are the first continuously cored geothermal exploration boreholes in Honduras. These coring operations are part of the Central America Energy Resource Project (CAERP) effort funded by the Agency for International Development (AID) and implemented by the Los Alamos National Laboratory (Los Alamos) in cooperation with the Empresa Nacional de Energia Electrica (ENEE) and the United States Geological Survey (USGS). This report emphasizes coring operations with reference to the stratigraphy, thermal gradient, and flow test data of the boreholes. The primary objectives of this coring effort were (1) to obtain quantitative information on the temperature distribution as a function of depth, (2) to recover fluids associated with the geothermal reservoir, (3) to recover 75% or better core from the subsurface rock units, and (4) to drill into the subsurface rock as deeply as possible in order to get information on potential reservoir rocks, fracture density, permeabilities, and alteration histories of the rock units beneath the site. The three exploration coreholes drilled to depths of 650, 428 and 679 m, respectively, encountered several hot water entries. Coring operations and associated testing began in mid-October 1986 and were completed at the end of June 1987.

  9. A high-gradient high-duty-factor Rf photo-cathode electron gun

    SciTech Connect (OSTI)

    Rimmer, Robert A.; Hartman, Neal; Lidia, Steven M.; Wang, Shaoheng

    2002-05-22

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

  10. The effect of density gradient on the growth rate of relativistic Weibel instability

    SciTech Connect (OSTI)

    Mahdavi, M.; Khodadadi Azadboni, F.

    2014-02-15

    In this paper, the effect of density gradient on the Weibel instability growth rate is investigated. The density perturbations in the near corona fuel, where temperature anisotropy, ?, is larger than the critical temperature anisotropy, ?{sub c}, (??>??{sub c}), enhances the growth rate of Weibel instability due to the sidebands coupled with the electron oscillatory velocity. But for ??thermal spread of the energetic electrons reduces the growth rate. Also, the growth rate can be reduced if the relativistic parameter (Lorentz factor) is sufficiently large, ??>?2. The analysis shows that relativistic effects and density gradient tend to stabilize the Weibel instability. The growth rate can be reduced by 88% by reducing ? by a factor of 100 and increasing relativistic parameter by a factor of 3.

  11. Micro-machined thermo-conductivity detector

    DOE Patents [OSTI]

    Yu, Conrad (Antioch, CA)

    2003-01-01

    A micro-machined thermal conductivity detector for a portable gas chromatograph. The detector is highly sensitive and has fast response time to enable detection of the small size gas samples in a portable gas chromatograph which are in the order of nanoliters. The high sensitivity and fast response time are achieved through micro-machined devices composed of a nickel wire, for example, on a silicon nitride window formed in a silicon member and about a millimeter square in size. In addition to operating as a thermal conductivity detector, the silicon nitride window with a micro-machined wire therein of the device can be utilized for a fast response heater for PCR applications.

  12. Validation of thermal models for a prototypical MEMS thermal actuator.

    SciTech Connect (OSTI)

    Gallis, Michail A.; Torczynski, John Robert; Piekos, Edward Stanley; Serrano, Justin Raymond; Gorby, Allen D.; Phinney, Leslie Mary

    2008-09-01

    This report documents technical work performed to complete the ASC Level 2 Milestone 2841: validation of thermal models for a prototypical MEMS thermal actuator. This effort requires completion of the following task: the comparison between calculated and measured temperature profiles of a heated stationary microbeam in air. Such heated microbeams are prototypical structures in virtually all electrically driven microscale thermal actuators. This task is divided into four major subtasks. (1) Perform validation experiments on prototypical heated stationary microbeams in which material properties such as thermal conductivity and electrical resistivity are measured if not known and temperature profiles along the beams are measured as a function of electrical power and gas pressure. (2) Develop a noncontinuum gas-phase heat-transfer model for typical MEMS situations including effects such as temperature discontinuities at gas-solid interfaces across which heat is flowing, and incorporate this model into the ASC FEM heat-conduction code Calore to enable it to simulate these effects with good accuracy. (3) Develop a noncontinuum solid-phase heat transfer model for typical MEMS situations including an effective thermal conductivity that depends on device geometry and grain size, and incorporate this model into the FEM heat-conduction code Calore to enable it to simulate these effects with good accuracy. (4) Perform combined gas-solid heat-transfer simulations using Calore with these models for the experimentally investigated devices, and compare simulation and experimental temperature profiles to assess model accuracy. These subtasks have been completed successfully, thereby completing the milestone task. Model and experimental temperature profiles are found to be in reasonable agreement for all cases examined. Modest systematic differences appear to be related to uncertainties in the geometric dimensions of the test structures and in the thermal conductivity of the polycrystalline silicon test structures, as well as uncontrolled nonuniform changes in this quantity over time and during operation.

  13. QUASI-STEADY CONFIGURATIONS OF CONDUCTIVE INTRACLUSTER MEDIA

    SciTech Connect (OSTI)

    Voit, G. M.

    2011-10-10

    The radial distributions of temperature, density, and gas entropy among cool-core clusters tend to be quite similar, suggesting that they have entered a quasi-steady state. If that state is regulated by a combination of thermal conduction and feedback from a central active galactic nucleus (AGN), then the characteristics of those radial profiles ought to contain information about the spatial distribution of AGN heat input and the relative importance of thermal conduction. This paper addresses those topics by deriving steady-state solutions for clusters in which radiative cooling, electron thermal conduction, and thermal feedback fueled by accretion are all present, with the aim of interpreting the configurations of cool-core clusters in terms of steady-state models. It finds that the core configurations of many cool-core clusters have entropy levels just below those of conductively balanced solutions in which magnetic fields have suppressed electron thermal conduction to {approx}1/3 of the full Spitzer value, suggesting that AGN feedback is triggered when conduction can no longer compensate for radiative cooling. And even when feedback is necessary to heat the central {approx}30 kpc, conduction may still be the most important heating mechanism within a cluster's central {approx}100 kpc.

  14. CONDUCTING A RECORDS INVENTORY

    Energy Savers [EERE]

    PROCEDURE FOR CONDUCTING A RECORDS INVENTORY Revision 1 10/31/07 Approved by: DOE Records Management Division, IM-23 PROCEDURE FOR CONDUCTING A RECORDS INVENTORY 1. GENERAL. A records inventory is compiling a descriptive list of each record series or system, including the location of the records and any other pertinent data. A records inventory is not a list of each document or each folder. 2. DEFINE THE RECORDS INVENTORY GOAL(S). The goals of a records inventory should be to: a. Gather

  15. Constant field gradient planar coupled cavity structure

    DOE Patents [OSTI]

    Kang, Y.W.; Kustom, R.L.

    1999-07-27

    A cavity structure is disclosed having at least two opposing planar housing members spaced apart to accommodate the passage of a particle beam through the structure between the members. Each of the housing members have a plurality of serially aligned hollows defined therein, and also passages, formed in the members, which interconnect serially adjacent hollows to provide communication between the hollows. The opposing planar housing members are spaced and aligned such that the hollows in one member cooperate with corresponding hollows in the other member to form a plurality of resonant cavities aligned along the particle beam within the cavity structure. To facilitate the obtaining of a constant field gradient within the cavity structure, the passages are configured so as to be incrementally narrower in the direction of travel of the particle beam. In addition, the spacing distance between the opposing housing members is configured to be incrementally smaller in the direction of travel of the beam. 16 figs.

  16. High gradient lens for charged particle beam

    DOE Patents [OSTI]

    Chen, Yu-Jiuan

    2014-04-29

    Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

  17. Lithium ion conducting electrolytes

    DOE Patents [OSTI]

    Angell, C.A.; Liu, C.

    1996-04-09

    A liquid, predominantly lithium-conducting, ionic electrolyte is described having exceptionally high conductivity at temperatures of 100 C or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH{sub 3}CN), succinnonitrile (CH{sub 2}CN){sub 2}, and tetraglyme (CH{sub 3}--O--CH{sub 2}--CH{sub 2}--O--){sub 2} (or like solvents) solvated to a Mg{sup +2} cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100 C conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone. 2 figs.

  18. Lithium ion conducting electrolytes

    DOE Patents [OSTI]

    Angell, C. Austen (Tempe, AZ); Liu, Changle (Tempe, AZ)

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte having exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH.sub.3 CN) succinnonitrile (CH.sub.2 CN).sub.2, and tetraglyme (CH.sub.3 --O--CH.sub.2 --CH.sub.2 --O--).sub.2 (or like solvents) solvated to a Mg.sup.+2 cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100.degree. C. conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone.

  19. Lithium ion conducting electrolytes

    DOE Patents [OSTI]

    Angell, Charles Austen (Mesa, AZ); Liu, Changle (Midland, MI); Xu, Kang (Montgomery Village, MD); Skotheim, Terje A. (Tucson, AZ)

    1999-01-01

    The present invention relates generally to highly conductive alkali-metal ion non-crystalline electrolyte systems, and more particularly to novel and unique molten (liquid), rubbery, and solid electrolyte systems which are especially well suited for use with high current density electrolytic cells such as primary and secondary batteries.

  20. Conduct of Operations

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2010-06-29

    This Order defines the requirements for establishing and implementing Conduct of Operations Programs at Department of Energy (DOE), including National Nuclear Security Administration (NNSA), facilities and projects. Cancels DOE O 5480.19. Admin Chg 1, dated 6-25-13, cancels DOE O 422.1. Certified 12-3-14.

  1. Control of Test Conduct

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2 Revision 1 Effective June 2008 Control of Test Conduct Prepared by Electric Transportation Applications Prepared by: _______________________________ Date:__________ Garrett P. Beauregard Approved by: _________________________________________________ Date: _______________ Donald B. Karner Procedure ETA-GAC002 Revision 1 2 Table of Contents 1 Objective ..................................................................................................................... 3 2

  2. Ocean Thermal Energy Conversion: An overview

    SciTech Connect (OSTI)

    Not Available

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the US Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential -- either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. This publication provides an overview of the OTEC technology. 47 refs., 25 figs.

  3. Functionally gradient material for membrane reactors to convert methane gas into value-added products

    DOE Patents [OSTI]

    Balachandran, U.; Dusek, J.T.; Kleefisch, M.S.; Kobylinski, T.P.

    1996-11-12

    A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials. 7 figs.

  4. Functionally gradient material for membrane reactors to convert methane gas into value-added products

    DOE Patents [OSTI]

    Balachandran, Uthamalingam (Hinsdale, IL); Dusek, Joseph T. (Lombard, IL); Kleefisch, Mark S. (Napersville, IL); Kobylinski, Thadeus P. (Lisle, IL)

    1996-01-01

    A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials.

  5. Thermoacoustic mixture separation with an axial temperature gradient

    SciTech Connect (OSTI)

    Geller, Drew W; Swift, Gregory A

    2008-01-01

    The theory of thermoacoustic mixture separation is extended to include the effect of a nonzero axial temperature gradient. The analysis yields a new term in the second-order mole flux that is proportional to the temperature gradient and to the square of the volumetric velocity and is independent of the phasing of the wave. Because of this new term, thermoacoustic separation stops at a critical temperature gradient and changes direction above that gradient. For a traveling wave, this gradient is somewhat higher than that predicted by a simple four-step model. An experiment tests the theory for temperature gradients from 0 to 416 K/m in 50-50 He-Ar mixtures.

  6. Electrically conductive alternating copolymers

    DOE Patents [OSTI]

    Aldissi, M.; Jorgensen, B.S.

    1987-08-31

    Polymers which are soluble in common organic solvents and are electrically conductive, but which also may be synthesized in such a manner that they become nonconductive. Negative ions from the electrolyte used in the electrochemical synthesis of a polymer are incorporated into the polymer during the synthesis and serve as a dopant. A further electrochemical step may be utilized to cause the polymer to be conductive. The monomer repeat unit is comprised of two rings, a pyrrole molecule joined to a thienyl group, or a furyl group, or a phenyl group. The individual groups of the polymers are arranged in an alternating manner. For example, the backbone arrangement of poly(furylpyrrole) is -furan-pyrrole-furan-pyrrole- furan-pyrrole. An alkyl group or phenyl group may be substituted for either or both of the hydrogen atoms of the pyrrole ring.

  7. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Vaughey, John; Krumpelt, Michael; Wang, Xiaoping; Carter, J. David

    2005-07-12

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  8. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Carter, J. David; Wang, Xiaoping; Vaughey, John; Krumpelt, Michael

    2004-11-23

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  9. Oxygen ion conducting materials

    DOE Patents [OSTI]

    Vaughey, John (Elmhurst, IL); Krumpelt, Michael (Naperville, IL); Wang, Xiaoping (Downers Grove, IL); Carter, J. David (Bolingbrook, IL)

    2003-01-01

    An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

  10. Super ionic conductive glass

    DOE Patents [OSTI]

    Susman, Sherman (Park Forest, IL); Volin, Kenneth J. (Fort Collins, CO)

    1984-01-01

    An ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A.sub.1+x D.sub.2-x/3 Si.sub.x P.sub.3-x O.sub.12-2x/3, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  11. High conductivity composite metal

    DOE Patents [OSTI]

    Zhou, R.; Smith, J.L.; Embury, J.D.

    1998-01-06

    Electrical conductors and methods of producing them are disclosed, where the conductors possess both high strength and high conductivity. Conductors are comprised of carbon steel and a material chosen from a group consisting of copper, nickel, silver, and gold. Diffusion barriers are placed between these two materials. The components of a conductor are assembled and then the assembly is subjected to heat treating and mechanical deformation steps. 10 figs.

  12. High conductivity composite metal

    DOE Patents [OSTI]

    Zhou, Ruoyi; Smith, James L.; Embury, John David

    1998-01-01

    Electrical conductors and methods of producing them, where the conductors possess both high strength and high conductivity. Conductors are comprised of carbon steel and a material chosen from a group consisting of copper, nickel, silver, and gold. Diffusion barriers are placed between these two materials. The components of a conductor are assembled and then the assembly is subjected to heat treating and mechanical deformation steps.

  13. Ion temperature gradient driven turbulence with strong trapped ion

    Office of Scientific and Technical Information (OSTI)

    resonance (Journal Article) | SciTech Connect Ion temperature gradient driven turbulence with strong trapped ion resonance Citation Details In-Document Search Title: Ion temperature gradient driven turbulence with strong trapped ion resonance A theory to describe basic characterization of ion temperature gradient driven turbulence with strong trapped ion resonance is presented. The role of trapped ion granulations, clusters of trapped ions correlated by precession resonance, is the focus.

  14. Humidifier for fuel cell using high conductivity carbon foam

    DOE Patents [OSTI]

    Klett, James W.; Stinton, David P.

    2006-12-12

    A method and apparatus of supplying humid air to a fuel cell is disclosed. The extremely high thermal conductivity of some graphite foams lends itself to enhance significantly the ability to humidify supply air for a fuel cell. By utilizing a high conductivity pitch-derived graphite foam, thermal conductivity being as high as 187 W/m.dot.K, the heat from the heat source is more efficiently transferred to the water for evaporation, thus the system does not cool significantly due to the evaporation of the water and, consequently, the air reaches a higher humidity ratio.

  15. Sensitivity of the interpretation of the experimental ion thermal

    Office of Scientific and Technical Information (OSTI)

    diffusivity to the determination of the ion conductive heat flux (Journal Article) | SciTech Connect Sensitivity of the interpretation of the experimental ion thermal diffusivity to the determination of the ion conductive heat flux Citation Details In-Document Search Title: Sensitivity of the interpretation of the experimental ion thermal diffusivity to the determination of the ion conductive heat flux A moments equation formalism for the interpretation of the experimental ion thermal

  16. Manufacture of gradient micro-structures of magnesium alloys using two stage extrusion dies

    SciTech Connect (OSTI)

    Hwang, Yeong-Maw; Huang, Tze-Hui [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, No. 70, Lien-Hai Rd., Kaohsiung, 804, Taiwan (China); Alexandrov, Sergei [Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow (Russian Federation); Naimark, Oleg Borisovich [Institute of Continuous Media Mechanics, Russian Academy of Sciences, Perm (Russian Federation); Jeng, Yeau-Ren [Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, Ming-Hsiung, Chia-Yi 621, Taiwan (China)

    2013-12-16

    This paper aims to manufacture magnesium alloy metals with gradient micro-structures using hot extrusion process. The extrusion die was designed to have a straight channel part combined with a conical part. Materials pushed through this specially-designed die generate a non-uniform velocity distribution at cross sections inside the die and result in different strain and strain rate distributions. Accordingly, a gradient microstructure product can be obtained. Using the finite element analysis, the forming temperature, effective strain, and effective strain rate distributions at the die exit were firstly discussed for various inclination angles in the conical die. Then, hot extrusion experiments with a two stage die were conducted to obtain magnesium alloy products with gradient micro-structures. The effects of the inclination angle on the grain size distribution at cross sections of the products were also discussed. Using a die of an inclination angle of 15, gradient micro-structures of the grain size decreasing gradually from 17 ?m at the center to 4 ?m at the edge of product were achieved.

  17. Ch. VII, Temperature, heat flow maps and temperature gradient...

    Open Energy Info (EERE)

    Report: Ch. VII, Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Editor T. G. Zacharakis Published Colorado Geological Survey in Cooperation...

  18. Temperature, heat flow maps and temperature gradient holes |...

    Open Energy Info (EERE)

    to library Report: Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Organization Colorado Geological Survey in Cooperation with the U.S....

  19. Permafrost and organic layer interactions over a climate gradient...

    Office of Scientific and Technical Information (OSTI)

    in permafrost occurrence (PF) and organic layer thickness (OLT) in more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships...

  20. Illinois: High-Energy, Concentration-Gradient Cathode Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High-Energy, Concentration-Gradient Cathode Material for Plug-in Hybrids and All-Electric Vehicles Could Reduce Batteries' Cost and Size Illinois: High-Energy,...

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

    SciTech Connect (OSTI)

    Johnson, Matthew ); Weyant, J.; Garner, S. ); Occhionero, M. )

    2010-01-07

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

  2. Science Highlights- Center for Solar and Thermal Energy Conversion

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (CNTs) Using Ultrafast Laser Irradiation Disordered Interfaces Improve Organic Photovoltaics New Way of Reducing Thermal Conductivity in Thermoelectric Materials Phase-field...

  3. Thermal properties of organic and inorganic aerogels

    SciTech Connect (OSTI)

    Hrubesh, L.W.; Pekala, R.W. (Chemistry and Material Science Department, Lawrence Livermore National Laboratory, Livermore, California 94551-9900 (United States))

    1994-03-01

    Aerogels are open-cell foams that have already been shown to be among the best thermal insulating solid materials known. This paper examines the three major contributions to thermal transport through porous materials; solid, gaseous, and radiative, to identify how to reduce the thermal conductivity of air-filled aerogels. We find that significant improvements in the thermal insulation property of aerogels are possible by; (i) employing materials with a low intrinsic solid conductivity, (ii) reducing the average pore size within aerogels, and (iii) affecting an increase of the infrared extinction in aerogels. Theoretically, polystyrene is the best of the organic materials and zirconia is the best inorganic material to use for the lowest achievable conductivity. Significant reduction of the thermal conductivity for all aerogel varieties is predicted with only a modest decrease of the average pore size. This might be achieved by modifying the sol-gel chemistry leading to aerogels. For example, a thermal resistance value of [ital R]=20 per inch would be possible for an air-filled resorcinol-formaldehyde aerogel at a density of 156 kg/m[sup 3], if the average pore size was less than 35 nm. An equation is included which facilitates the calculation of the optimum density for the minimum total thermal conductivity, for all varieties of aerogels.

  4. Conducting polymer ultracapacitor

    DOE Patents [OSTI]

    Shi, Steven Z. (Latham, NY); Davey, John R. (Los Alamos, NM); Gottesfeld, Shimshon (Los Alamos, NM); Ren, Xiaoming (Los Alamos, NM)

    2002-01-01

    A sealed ultracapacitor assembly is formed with first and second electrodes of first and second conducting polymers electrodeposited on porous carbon paper substrates, where the first and second electrodes each define first and second exterior surfaces and first and second opposing surfaces. First and second current collector plates are bonded to the first and second exterior surfaces, respectively. A porous membrane separates the first and second opposing surfaces, with a liquid electrolyte impregnating the insulating membrane. A gasket formed of a thermoplastic material surrounds the first and second electrodes and seals between the first and second current collector plates for containing the liquid electrolyte.

  5. Borehole Fluid Conductivity Model

    Energy Science and Technology Software Center (OSTI)

    2004-03-15

    Dynamic wellbore electrical conductivity logs provide a valuable means to determine the flow characteristics of fractures intersectin a wellbore, in order to study the hydrologic behavior of fractured rocks. To expedite the analysis of log data, a computer program called BORE II has been deveoloped that considers multiple inflow or outflow points along the wellbore, including the case of horizontal flow across the wellbore, BORE II calculates the evolution of fluid electrical conducivity (FEC) profilesmorein a wellbore or wellbore section, which may be pumped at a low rate, and compares model results to log data in a variety of ways. FEC variations may arise from inflow under natural-state conditions or due to tracer injected in a neighboring well (interference tests). BORE II has an interactive, graphical user interface and runs on a personal computer under the Windows operating system. BORE II is a modification and extension of older codes called BORE and BOREXT, which considered inflow points only. Finite difference solution of the one-dimensional advection-diffusion equation with explicit time stepping; feed points treated as prescribed-mass sources or sinks; assume quadratic relationship between fluid electrical conductivity and ion consentration. Graphical user interface; interactive modification of model parameters and graphical display of model results and filed data in a variety of ways. Can examine horizontal flow or arbitarily complicated combination of upflow, downflow, and horizontal flow. Feed point flow rate and/or concentration may vary in time.less

  6. Coronal heating driven by a magnetic gradient pumping mechanism in solar plasmas

    SciTech Connect (OSTI)

    Tan, Baolin

    2014-11-10

    The heating of the solar corona is a longstanding mystery in astrophysics. Considering that the solar magnetic field is spatially inhomogeneous with a considerable magnetic gradient from the solar surface to the corona, this work proposes a magnetic gradient pumping (MGP) mechanism to try to explain the formation of hot plasma upflows, such as hot type II spicules and hot plasma ejections. In the MGP mechanism, the magnetic gradient may drive the energetic particles to move upward from the underlying solar atmosphere and form hot upflows. These upflow energetic particles are deposited in the corona, causing it to become very hot. Rough estimations indicate that the solar corona can be heated to above 1 million degrees, and the upflow velocity is about 40 km s{sup 1} in the chromosphere and about 130 km s{sup 1} in the corona. The solar magnetic flux tubes act as pumpers to extract energetic particles from the underlying thermal photosphere, convey them, and deposit them in the corona. The deposit of these energetic particles causes the corona to become hot, and the escape of such particles from the photosphere leaves it a bit cold. This mechanism can present a natural explanation to the mystery of solar coronal heating.

  7. Lateral conduction infrared photodetector

    DOE Patents [OSTI]

    Kim, Jin K. (Albuquerque, NM); Carroll, Malcolm S. (Albuquerque, NM)

    2011-09-20

    A photodetector for detecting infrared light in a wavelength range of 3-25 .mu.m is disclosed. The photodetector has a mesa structure formed from semiconductor layers which include a type-II superlattice formed of alternating layers of InAs and In.sub.xGa.sub.1-xSb with 0.ltoreq.x.ltoreq.0.5. Impurity doped regions are formed on sidewalls of the mesa structure to provide for a lateral conduction of photo-generated carriers which can provide an increased carrier mobility and a reduced surface recombination. An optional bias electrode can be used in the photodetector to control and vary a cut-off wavelength or a depletion width therein. The photodetector can be formed as a single-color or multi-color device, and can also be used to form a focal plane array which is compatible with conventional read-out integrated circuits.

  8. Efficient and robust gradient enhanced Kriging emulators.

    SciTech Connect (OSTI)

    Dalbey, Keith R.

    2013-08-01

    %E2%80%9CNaive%E2%80%9D or straight-forward Kriging implementations can often perform poorly in practice. The relevant features of the robustly accurate and efficient Kriging and Gradient Enhanced Kriging (GEK) implementations in the DAKOTA software package are detailed herein. The principal contribution is a novel, effective, and efficient approach to handle ill-conditioning of GEK's %E2%80%9Ccorrelation%E2%80%9D matrix, RN%CC%83, based on a pivoted Cholesky factorization of Kriging's (not GEK's) correlation matrix, R, which is a small sub-matrix within GEK's RN%CC%83 matrix. The approach discards sample points/equations that contribute the least %E2%80%9Cnew%E2%80%9D information to RN%CC%83. Since these points contain the least new information, they are the ones which when discarded are both the easiest to predict and provide maximum improvement of RN%CC%83's conditioning. Prior to this work, handling ill-conditioned correlation matrices was a major, perhaps the principal, unsolved challenge necessary for robust and efficient GEK emulators. Numerical results demonstrate that GEK predictions can be significantly more accurate when GEK is allowed to discard points by the presented method. Numerical results also indicate that GEK can be used to break the curse of dimensionality by exploiting inexpensive derivatives (such as those provided by automatic differentiation or adjoint techniques), smoothness in the response being modeled, and adaptive sampling. Development of a suitable adaptive sampling algorithm was beyond the scope of this work; instead adaptive sampling was approximated by omitting the cost of samples discarded by the presented pivoted Cholesky approach.

  9. Non-linear Conjugate Gradient Time-Domain Controlled Inversion Source

    Energy Science and Technology Software Center (OSTI)

    2006-11-16

    Software that simulates and inverts time-domain electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a step-wise source signal from either galvanic (grounded wires) or inductive (magnetic loops) sources. The inversion process is carried inductive (magnetic loops) sources. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code TEM3D ver. 2.0. The upgrade includes the following components: (1) Improved (faster)memory access during gradient computation. (2) Data parellelization scheme: Multiple transmitters (sources) can be distributed accross several banks of processors (daa-planes). Similarly, the receivers of each source are also distributed accross the corresponding data-plane. (3) Improved data-IO.« less

  10. NON-SCALING FIXED FIELD GRADIENT OPTIMIZATION.

    SciTech Connect (OSTI)

    TRBOJEVIC, D.

    2004-10-13

    Optimization of the non-scaling FFAG lattice for the specific application of the muon acceleration with respect to the minimum orbit offsets, minimum path length and smallest circumference is described. The short muon lifetime requires fast acceleration. The acceleration is in this work assumed to be with super-conducting cavities. This sets up a condition of acceleration at the top of the sinusoidal RF wave.

  11. Bernstein instability driven by thermal ring distribution

    SciTech Connect (OSTI)

    Yoon, Peter H.; Hadi, Fazal; Qamar, Anisa

    2014-07-15

    The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function.

  12. Thermal Batteries for Electric Vehicles

    SciTech Connect (OSTI)

    2011-11-21

    HEATS Project: UT Austin will demonstrate a high-energy density and low-cost thermal storage system that will provide efficient cabin heating and cooling for EVs. Compared to existing HVAC systems powered by electric batteries in EVs, the innovative hot-and-cold thermal batteries-based technology is expected to decrease the manufacturing cost and increase the driving range of next-generation EVs. These thermal batteries can be charged with off-peak electric power together with the electric batteries. Based on innovations in composite materials offering twice the energy density of ice and 10 times the thermal conductivity of water, these thermal batteries are expected to achieve a comparable energy density at 25% of the cost of electric batteries. Moreover, because UT Austins thermal energy storage systems are modular, they may be incorporated into the heating and cooling systems in buildings, providing further energy efficiencies and positively impacting the emissions of current building heating/cooling systems.

  13. Thermal Degradation Behavior of Siloxane Elastomer Impregnated Carbon

    Office of Scientific and Technical Information (OSTI)

    Nanotube Areogel Networks (Conference) | SciTech Connect Conference: Thermal Degradation Behavior of Siloxane Elastomer Impregnated Carbon Nanotube Areogel Networks Citation Details In-Document Search Title: Thermal Degradation Behavior of Siloxane Elastomer Impregnated Carbon Nanotube Areogel Networks A novel class of nanoporous graphitic carbon foams has been synthesized. Unprecedented properties - electrically conductive, thermally stable (> 1000 C), and mechanically robust. Improved

  14. Cross-plane thermal properties of transition metal dichalcogenides

    SciTech Connect (OSTI)

    Muratore, C.; Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 ; Varshney, V.; Universal Technology Corporation, Dayton, Ohio 45432 ; Gengler, J. J.; Spectral Energies LLC, Dayton, Ohio 45431 ; Hu, J. J.; Bultman, J. E.; University of Dayton Research Institute, Dayton, Ohio 45469 ; Smith, T. M.; Shamberger, P. J.; Roy, A. K.; Voevodin, A. A.; Qiu, B.; Ruan, X.

    2013-02-25

    In this work, we explore the thermal properties of hexagonal transition metal dichalcogenide compounds with different average atomic masses but equivalent microstructures. Thermal conductivity values of sputtered thin films were compared to bulk crystals. The comparison revealed a >10 fold reduction in thin film thermal conductivity. Structural analysis of the films revealed a turbostratic structure with domain sizes on the order of 5-10 nm. Estimates of phonon scattering lengths at domain boundaries based on computationally derived group velocities were consistent with the observed film microstructure, and accounted for the reduction in thermal conductivity compared to values for bulk crystals.

  15. Conductive lithium storage electrode

    DOE Patents [OSTI]

    Chiang, Yet-Ming (Framingham, MA); Chung, Sung-Yoon (Seoul, KR); Bloking, Jason T. (Cambridge, MA); Andersson, Anna M. (Uppsala, SE)

    2008-03-18

    A compound comprising a composition A.sub.x(M'.sub.1-aM''.sub.a).sub.y(XD.sub.4).sub.z, A.sub.x(M'.sub.1-aM''.sub.a).sub.y(DXD.sub.4).sub.z, or A.sub.x(M'.sub.1-aM''.sub.a).sub.y(X.sub.2D.sub.7).sub.z, and have values such that x, plus y(1-a) times a formal valence or valences of M', plus ya times a formal valence or valence of M'', is equal to z times a formal valence of the XD.sub.4, X.sub.2D.sub.7, or DXD.sub.4 group; or a compound comprising a composition (A.sub.1-aM''.sub.a).sub.xM'.sub.y(XD.sub.4).sub.z, (A.sub.1-aM''.sub.a).sub.xM'.sub.y(DXD.sub.4).sub.z(A.sub.1-aM''.sub.a).s- ub.xM'.sub.y(X.sub.2D.sub.7).sub.z and have values such that (1-a).sub.x plus the quantity ax times the formal valence or valences of M'' plus y times the formal valence or valences of M' is equal to z times the formal valence of the XD.sub.4, X.sub.2D.sub.7 or DXD.sub.4 group. In the compound, A is at least one of an alkali metal and hydrogen, M' is a first-row transition metal, X is at least one of phosphorus, sulfur, arsenic, molybdenum, and tungsten, M'' any of a Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at least one of oxygen, nitrogen, carbon, or a halogen, 0.0001conductivity at 27.degree. C. of at least about 10.sup.-8 S/cm. The compound can be a doped lithium phosphate that can intercalate lithium or hydrogen. The compound can be used in an electrochemical device including electrodes and storage batteries and can have a gravimetric capacity of at least about 80 mAh/g while being charged/discharged at greater than about C rate of the compound.

  16. Conductive lithium storage electrode

    DOE Patents [OSTI]

    Chiang, Yet-Ming (Framingham, MA); Chung, Sung-Yoon (Incheon, KR); Bloking, Jason T. (Mountain View, CA); Andersson, Anna M. (Vasteras, SE)

    2012-04-03

    A compound comprising a composition A.sub.x(M'.sub.1-aM''.sub.a).sub.y(XD.sub.4).sub.z, A.sub.x(M'.sub.1-aM''.sub.a).sub.y(DXD.sub.4).sub.z, or A.sub.x(M'.sub.1-aM''.sub.a).sub.y(X.sub.2D.sub.7).sub.z, and have values such that x, plus y(1-a) times a formal valence or valences of M', plus ya times a formal valence or valence of M'', is equal to z times a formal valence of the XD.sub.4, X.sub.2D.sub.7, or DXD.sub.4 group; or a compound comprising a composition (A.sub.1-aM''.sub.a).sub.xM'.sub.y(XD.sub.4).sub.z, (A.sub.1-aM''.sub.a).sub.xM'.sub.y(DXD.sub.4).sub.z (A.sub.1-aM''.sub.a).sub.xM'.sub.y(X.sub.2D.sub.7).sub.z and have values such that (1-a).sub.x plus the quantity ax times the formal valence or valences of M'' plus y times the formal valence or valences of M' is equal to z times the formal valence of the XD.sub.4, X.sub.2D.sub.7 or DXD.sub.4 group. In the compound, A is at least one of an alkali metal and hydrogen, M' is a first-row transition metal, X is at least one of phosphorus, sulfur, arsenic, molybdenum, and tungsten, M'' any of a Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at least one of oxygen, nitrogen, carbon, or a halogen, 0.0001conductivity at 27.degree. C. of at least about 10.sup.-8 S/cm. The compound can be a doped lithium phosphate that can intercalate lithium or hydrogen. The compound can be used in an electrochemical device including electrodes and storage batteries and can have a gravimetric capacity of at least about 80 mAh/g while being charged/discharged at greater than about C rate of the compound.

  17. Pressurized electrolysis stack with thermal expansion capability

    DOE Patents [OSTI]

    Bourgeois, Richard Scott

    2015-07-14

    The present techniques provide systems and methods for mounting an electrolyzer stack in an outer shell so as to allow for differential thermal expansion of the electrolyzer stack and shell. Generally, an electrolyzer stack may be formed from a material with a high coefficient of thermal expansion, while the shell may be formed from a material having a lower coefficient of thermal expansion. The differences between the coefficients of thermal expansion may lead to damage to the electrolyzer stack as the shell may restrain the thermal expansion of the electrolyzer stack. To allow for the differences in thermal expansion, the electrolyzer stack may be mounted within the shell leaving a space between the electrolyzer stack and shell. The space between the electrolyzer stack and the shell may be filled with a non-conductive fluid to further equalize pressure inside and outside of the electrolyzer stack.

  18. Effects of thermal fluctuations on thermal inflation

    SciTech Connect (OSTI)

    Hiramatsu, Takashi; Miyamoto, Yuhei; Yokoyama, Jun’ichi

    2015-03-12

    The mechanism of thermal inflation, a relatively short period of accelerated expansion after primordial inflation, is a desirable ingredient for a certain class of particle physics models if they are not to be in contention with the cosmology of the early Universe. Though thermal inflation is most simply described in terms of a thermal effective potential, a thermal environment also gives rise to thermal fluctuations that must be taken into account. We numerically study the effects of these thermal fluctuations using lattice simulations. We conclude that though they do not ruin the thermal inflation scenario, the phase transition at the end of thermal inflation proceeds through phase mixing and is therefore not accompanied by the formations of bubbles nor appreciable amplitude of gravitational waves.

  19. High Temperature Thermal Array for Next Generation Solar Thermal...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High Temperature Thermal Array for Next Generation Solar Thermal Power Production High Temperature Thermal Array for Next Generation Solar Thermal Power Production This ...

  20. Observation of 690 MV m^-1 Electron Accelerating Gradient with...

    Office of Scientific and Technical Information (OSTI)

    Observation of 690 MV m-1 Electron Accelerating Gradient with a Laser-Driven Dielectric Microstructure Citation Details In-Document Search Title: Observation of 690 MV m-1...

  1. Field Investigations And Temperature-Gradient Drilling At Marine...

    Open Energy Info (EERE)

    Investigations And Temperature-Gradient Drilling At Marine Corps Air-Ground Combat Center (Mcagcc), Twenty-Nine Palms, Ca Jump to: navigation, search OpenEI Reference LibraryAdd to...

  2. Developing new high energy gradient concentration cathode material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon esp10amine.pdf More Documents & Publications New High Energy Gradient Concentration ...

  3. Illinois: High-Energy, Concentration-Gradient Cathode Material...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    a high-energy, concentration-gradient cathode material for plug-in hybrid and all-electric vehicles. ... market growth, leading to reductions in carbon pollution and imported oil. ...

  4. Comparative systems biology across an evolutionary gradient within the

    Office of Scientific and Technical Information (OSTI)

    Shewanella genus (Journal Article) | SciTech Connect Comparative systems biology across an evolutionary gradient within the Shewanella genus Citation Details In-Document Search Title: Comparative systems biology across an evolutionary gradient within the Shewanella genus To what extent genotypic differences translate to phenotypic variation remains a poorly understood issue of paramount importance for several cornerstone concepts of microbiology such as the species definition. Here, we take

  5. Stress gradients in electrodeposited Ni MEMS. (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Stress gradients in electrodeposited Ni MEMS. Citation Details In-Document Search Title: Stress gradients in electrodeposited Ni MEMS. No abstract prepared. Authors: Hearne, Sean Joseph ; Floro, Jerrold Anthony ; Dyck, Christopher William Publication Date: 2004-06-01 OSTI Identifier: 957295 Report Number(s): SAND2004-3006C TRN: US201007%%569 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: Proposed for presentation at the Electrochemical

  6. Theory of factors limiting high gradient operation of warm accelerating

    Office of Scientific and Technical Information (OSTI)

    structures (Technical Report) | SciTech Connect Theory of factors limiting high gradient operation of warm accelerating structures Citation Details In-Document Search Title: Theory of factors limiting high gradient operation of warm accelerating structures This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded

  7. Thermal protection apparatus

    DOE Patents [OSTI]

    Bennett, Gloria A. (Los Alamos, NM); Moore, Troy K. (Los Alamos, NM)

    1988-01-01

    An apparatus for thermally protecting heat sensitive components of tools. The apparatus comprises a Dewar for holding the heat sensitive components. The Dewar has spaced-apart inside and outside walls, an open top end and a bottom end. An insulating plug is located in the top end. The inside wall has portions defining an inside wall aperture located at the bottom of the Dewar and the outside wall has portions defining an outside wall aperture located at the bottom of the Dewar. A bottom connector has inside and outside components. The inside component sealably engages the inside wall aperture and the outside component sealably engages the outside wall aperture. The inside component is operatively connected to the heat sensitive components and to the outside component. The connections can be made with optical fibers or with electrically conducting wires.

  8. Project Profile: Novel Molten Salts Thermal Energy Storage for

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Concentrating Solar Power Generation | Department of Energy Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation Project Profile: Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation Alabama logo The University of Alabama, under the Thermal Storage FOA, is developing thermal energy storage (TES) media consisting of low melting point (LMP) molten salt with high TES density for sensible heat storage systems. Approach They will conduct

  9. Thermal Control & System Integration

    Broader source: Energy.gov [DOE]

    The thermal control and system integration activity focuses on issues such as the integration of motor and power control technologies and the development of advanced thermal control technologies....

  10. Effect of graphite properties in thermal analysis of CHTR: A parametric study

    SciTech Connect (OSTI)

    Kaushik, Ankur; Basak, Abhishek; Dulera, I. V.; Vijayan, P. K.

    2013-06-12

    Compact High Temperature Reactor (CHTR) is a {sup 233}U-Thorium fuelled, lead-bismuth cooled reactor. The CHTR core mainly consists of graphite and beryllium oxide (BeO). The CHTR core consists of nineteen prismatic beryllium oxide (BeO) moderator blocks. These 19 blocks contain centrally located graphite fuel tubes. The BeO moderator blocks are surrounded by reflector blocks (partially graphite and partially BeO). The nuclear heat from the core is removed passively by natural circulation of the coolant between top and bottom plenums, upward through the fuel tubes and returning through the downcomer tubes at the periphery. The temperature gradient in fuel tubes, downcomer tubes and BeO is very high and therefore, to take care of the differential thermal expansion, gaps are provided in the core between the tubes and other core components. These gaps affect the heat transfer through the core in radial direction. In addition, there is a large variation in thermal properties of graphite which in turn affects the thermal behaviour of the core in various operating conditions. The fuel of CHTR is TRISO coated particle fuel. These particles are packed in with graphite powder as matrix and made into cylindrical compacts these compacts are packed in the bores of fuel tube. In this study, the effect of the thermal conductivity variation of the graphite on the temperature distribution of the core and density variation of the matrix graphite material in fuel compact on the maximum fuel kernel temperature is studied along with the overall role of graphite properties variation in heat transfer.

  11. Edge Temperature Gradient as Intrinsic Rotation Drive in AlcatorC...

    Office of Scientific and Technical Information (OSTI)

    Edge Temperature Gradient as Intrinsic Rotation Drive in AlcatorC-Mod Tokamak Plasmas Citation Details In-Document Search Title: Edge Temperature Gradient as Intrinsic Rotation...

  12. New results of development on high efficiency high gradient superconducting rf cavities

    SciTech Connect (OSTI)

    Geng, Rongli; Li, Z.; Hao, K.; Liu, K.-X.; Zhao, H.-Y.; Adolphsen, C.

    2015-09-01

    We report on the latest results of development on high efficiency high gradient superconducting radio frequency (SRF) cavities. Several 1-cell cavities made of large-grain niobium (Nb) were built, processed and tested. Two of these cavities are of the Low Surface Field (LSF) shape. Series of tests were carried out following controlled thermal cycling. Experiments toward zero-field cooling were carried out. The best experimentally achieved results are Eacc = 41 MV/m at Q0 = 6.5×1010 at 1.4 K by a 1-cell 1.3 GHz large-grain Nb TTF shape cavity and Eacc = 49 MV/m at Q0 = 1.5×1010 at 1.8 K by a 1-cell 1.5 GHz large-grain Nb CEBAF upgrade low-loss shape cavity.

  13. Latest Results of ILC High-Gradient R&D 9-cell Cavities at JLAB

    SciTech Connect (OSTI)

    Rongli Geng

    2008-02-11

    It has been over a year since JLAB started processing and testing ILC 9-cell cavities in the frame work of ILC high-gradient cavity R&D, aiming at the goal of a 35 MV/m gradient at a Q #4; of 1E10 with a yield of 90%. The necessary cavity processing steps include field flatness tuning, electropolishing (EP), hydrogen out-gassing under vacuum, high-pressure water rinsing, clean room assembly, and low temperature bake. These are followed by RF test at 2 Kelvin. Ultrasonic cleaning with Micro-90, an effective post-EP rinsing recipe discovered at JLAB, is routinely used. Seven industry manufactured 9-cell TESLAshape cavities are processed and tested repeatedly. So far, 33 EP cycles are accumulated, corresponding to more than 65 hours of active EP time. An emphasis put on RF testing is to discern cavity quench characteristics, including its nature and its location. Often times, the cavity performance is limited by thermal-magnetic quench instead of field emission. The quench field in some cavities is lower than 20 MV/m and remains unchanged despite repeated EP, implying material and/or fabrication defects. The quench field in some other cavities is high but changes unpredictably after repeated EP, suggesting processing induced defects. Based on our experience and results, several areas are identified where improvement is needed to improve cavity performance as well as yield.

  14. Nonlocal Thermal Transport across Embedded Few-Layer Graphene Sheets

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Liu, Ying; Huxtable, Scott T; Yang, Bao; Sumpter, Bobby G; Qiao, Rui

    2014-01-01

    Thermal transport across the interfaces between few-layer graphene sheets and soft materials exhibits intriguing anomalies when interpreted using the classical Kapitza model, e.g., the conductance of the same interface differs greatly for different modes of interfacial thermal transport. Using atomistic simulations, we show that such thermal transport follows a nonlocal flux-temperature drop constitutive law and is characterized jointly by a quasi-local conductance and a nonlocal conductance instead of the classical Kapitza conductance. The nonlocal model enables rationalization of many anomalies of the thermal transport across embedded few-layer graphene sheets and should be used in studies of interfacial thermal transport involvingmore » few-layer graphene sheets or other ultra-thin layered materials.« less

  15. Fabrication of back-contacted silicon solar cells using thermomigration to create conductive vias

    DOE Patents [OSTI]

    Gee, James M; Schmit, Russell R.

    2007-01-30

    Methods of manufacturing back-contacted silicon solar cells fabricated using a gradient-driven solute transport process, such as thermomigration or electromigration, to create n-type conductive vias connecting the n-type emitter layer on the front side to n-type ohmic contacts located on the back side.

  16. THERMAL OSCILLATIONS IN LIQUID HELIUM TARGETS.

    SciTech Connect (OSTI)

    WANG,L.; JIA,L.X.

    2001-07-16

    A liquid helium target for the high-energy physics was built and installed in the proton beam line at the Alternate Gradient Synchrotron of Brookhaven National Laboratory in 2001. The target flask has a liquid volume of 8.25 liters and is made of thin Mylar film. A G-M/J-T cryocooler of five-watts at 4.2K was used to produce liquid helium and refrigerate the target. A thermosyphon circuit for the target was connected to the J-T circuit by a liquid/gas separator. Because of the large heat load to the target and its long transfer lines, thermal oscillations were observed during the system tests. To eliminate the oscillation, a series of tests and analyses were carried out. This paper describes the phenomena and provides the understanding of the thermal oscillations in the target system.

  17. Appendix C Conducting Structured Walkthroughs

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1997-05-21

    This guide describes how to conduct a structured walkthroughs during the lifecycle stages of software engineering projects, regardless of hardware platform.

  18. Gradient isolator for flow field of fuel cell assembly

    DOE Patents [OSTI]

    Ernst, William D.

    1999-01-01

    Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions.

  19. Gradient isolator for flow field of fuel cell assembly

    DOE Patents [OSTI]

    Ernst, W.D.

    1999-06-15

    Isolator(s) include isolating material and optionally gasketing material strategically positioned within a fuel cell assembly. The isolating material is disposed between a solid electrolyte and a metal flow field plate. Reactant fluid carried by flow field plate channel(s) forms a generally transverse electrochemical gradient. The isolator(s) serve to isolate electrochemically a portion of the flow field plate, for example, transversely outward from the channel(s), from the electrochemical gradient. Further, the isolator(s) serve to protect a portion of the solid electrolyte from metallic ions. 4 figs.

  20. Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines

    SciTech Connect (OSTI)

    Mumm, Daniel

    2013-08-31

    The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments relative to traditional natural gas fired systems affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive/thermo-chemical attack mechanisms; (iv) developing a mechanics-based analysis of the driving forces for crack growth and delamination, based on molten phase infiltration, misfit upon cooling, and loss of compliance; (v) understanding changes in TGO growth mechanisms associated with these emerging combustion product streams; and (vi) identifying degradation resistant alternative materials (including new compositions or bi-layer concepts) for use in mitigating the observed degradation modes. To address the materials stability concerns, this program integrated research thrusts aimed at: (1) Conducting tests in simulated syngas and HHC environments to evaluate materials evolution and degradation mechanisms; assessing thermally grown oxide development unique to HHC environmental exposures; carrying out high-resolution imaging and microanalysis to elucidate the evolution of surface deposits (molten phase formation and infiltration); exploring thermo-chemical instabilities; assessing thermo-mechanical drivers and thermal gradient effects on degradation; and quantitatively measuring stress evolution due to enhanced sintering and thermo-chemical instabilities induced in the coating. (2) Executing experiments to study the melting and infiltration of simulated ash deposits, and identifying reaction products and evolving phases associated with molten phase corrosion mechanisms; utilizing thermal spray techniques to fabricate test coupons with controlled microstructures to study mechanisms of instability and degradation; facilitating thermal gradient testing; and developing new materials systems for laboratory testing; (3) Correlating information on the resulting combustion environments to properly assess materials exposure conditions and guide the development of lab-scale simulations of material exposures; specification of representative syngas and high-hydrogen fuels with realistic levels of impurities and contaminants, to explore differences in heat transfer, surface degradation, and deposit formation; and facilitating combustion rig testing of materials test coupons.

  1. HEATS: Thermal Energy Storage

    SciTech Connect (OSTI)

    2012-01-01

    HEATS Project: The 15 projects that make up ARPA-Es 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.

  2. Conductive polymer-based material

    DOE Patents [OSTI]

    McDonald, William F. (Utica, OH); Koren, Amy B. (Lansing, MI); Dourado, Sunil K. (Ann Arbor, MI); Dulebohn, Joel I. (Lansing, MI); Hanchar, Robert J. (Charlotte, MI)

    2007-04-17

    Disclosed are polymer-based coatings and materials comprising (i) a polymeric composition including a polymer having side chains along a backbone forming the polymer, at least two of the side chains being substituted with a heteroatom selected from oxygen, nitrogen, sulfur, and phosphorus and combinations thereof; and (ii) a plurality of metal species distributed within the polymer. At least a portion of the heteroatoms may form part of a chelation complex with some or all of the metal species. In many embodiments, the metal species are present in a sufficient concentration to provide a conductive material, e.g., as a conductive coating on a substrate. The conductive materials may be useful as the thin film conducting or semi-conducting layers in organic electronic devices such as organic electroluminescent devices and organic thin film transistors.

  3. Digital Manufacturing of Gradient Meshed SOFC Sealing Composites with Self-Healing Capabilities

    SciTech Connect (OSTI)

    Kathy Lu; Christopher Story; W.T. Reynolds

    2007-12-21

    Solid oxide fuel cells (SOFC) hold great promise for clean power generation. However, high temperature stability and long term durability of the SOFC components have presented serious problems in SOFC technological advancement and commercialization. The seals of the fuel cells are the most challenging area to address. A high temperature gas seal is highly needed which is durable against cracking and gas leakage during thermal cycling and extended operation. This project investigates a novel composite seal by integrating 3D printed shape memory alloy (SMA) wires into a glass matrix. The SMA we use is TiNiHf and the glass matrix we use is SrO-La{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-B{sub 2}O{sub 3}-SiO{sub 2} (SLABS). Dilatometry shows to be an extremely useful tool in providing the CTEs. It pinpoints regions of different CTEs under simulated SOFC thermal cycles for the same glass. For the studied SLABS glass system, the region with the greatest CTE mismatch between the glass seal and the adjacent components is 40-500 C, the typical heating and cooling regions for SOFCs. Even for low temperature SOFC development, this region is still present and needs to be addressed. We have demonstrated that the proposed SLABS glass has great potential in mitigating the thermal expansion mismatch issues that are limiting the operation life of SOFCs. TiNiHf alloy has been successfully synthesized with the desired particle size for the 3DP process. The TiNiHf SMA shape memory effect very desirably overlaps with the problematic low CTE region of the glass. This supports the design intent that the gradient structure transition, phase transformation toughening, and self-healing of the SMA can be utilized to mitigate/eliminate the seal problem. For the 3DP process, a new binder has been identified to match with the specific chemistry of the SMA particles. This enables us to directly print SMA particles. Neutron diffraction shows to be an extremely useful tool in providing information regarding the austenite to martensite phase transformation, SMA alloy lattice constant change, and the corresponding thermal stress from the glass matrix. It pinpoints regions of SMA phase transformation and the thermal stress effect under simulated SOFC thermal cycles. The bilayer test shows that there is still much work to be done for the proper integration of the seal components. Large scale production should lower the cost associated with the proposed approach, especially on the raw material cost and 3D printing.

  4. Microwavable thermal energy storage material

    DOE Patents [OSTI]

    Salyer, I.O.

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments. 3 figs.

  5. Microwavable thermal energy storage material

    DOE Patents [OSTI]

    Salyer, Ival O. (Dayton, OH)

    1998-09-08

    A microwavable thermal energy storage material is provided which includes a mixture of a phase change material and silica, and a carbon black additive in the form of a conformable dry powder of phase change material/silica/carbon black, or solid pellets, films, fibers, moldings or strands of phase change material/high density polyethylene/ethylene-vinyl acetate/silica/carbon black which allows the phase change material to be rapidly heated in a microwave oven. The carbon black additive, which is preferably an electrically conductive carbon black, may be added in low concentrations of from 0.5 to 15% by weight, and may be used to tailor the heating times of the phase change material as desired. The microwavable thermal energy storage material can be used in food serving applications such as tableware items or pizza warmers, and in medical wraps and garments.

  6. Thermal Energy Storage

    SciTech Connect (OSTI)

    Rutberg, Michael; Hastbacka, Mildred; Cooperman, Alissa; Bouza, Antonio

    2013-06-05

    The article discusses thermal energy storage technologies. This article addresses benefits of TES at both the building site and the electricity generation source. The energy savings and market potential of thermal energy store are reviewed as well.

  7. Electrical conductivity of pyrolyzed polyacrylonitrile

    SciTech Connect (OSTI)

    Teoh, H.; Metz, P.D.; Wilhelm, W.G.

    1981-01-01

    Using ultrapure samples of polyacrylonitrile (PAN) of 485,000 or 150,000 average molecular weight solution cast in dimethylformamide, the dc conductivity (sigma) of pyrolyzed PAN (PANP) films has been studied for pyrolysis temperatures (T/ sub p/) of 280 to 435/sup 0/C. Conductivity measurements made during pyrolysis indicate the onset of a dramatic increase in sigma for T/sub p/ of 390 to 435/sup 0/C. Conductivities as high as 5 (ohm-cm)/sup -1/ have been observed for T/sub p/ < 435/sup 0/C.

  8. Advanced Wellbore Thermal Simulator

    Energy Science and Technology Software Center (OSTI)

    1992-03-04

    GEOTEMP2, which is based on the earlier GEOTEMP program, is a wellbore thermal simulator designed for geothermal well drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A variety of well operations can be modeled including injection, production, forward and reverse circulation with gas or liquid, gas or liquid drilling, and two-phase steam injection and production. Well completion with severalmore » different casing sizes and cement intervals can be modeled. The code allows variables, such as flow rate, to change with time enabling a realistic treatment of well operations. Provision is made in the flow equations to allow the flow areas of the tubing to vary with depth in the wellbore. Multiple liquids can exist in GEOTEMP2 simulations. Liquid interfaces are tracked through the tubing and annulus as one liquid displaces another. GEOTEMP2, however, does not attempt to simulate displacement of liquids with a gas or two-phase steam or vice versa. This means that it is not possible to simulate an operation where the type of drilling fluid changes, e.g. mud going to air. GEOTEMP2 was designed primarily for use in predicting the behavior of geothermal wells, but it is flexible enough to handle many typical drilling, production, and injection problems in the oil industry as well. However, GEOTEMP2 does not allow the modeling of gas-filled annuli in production or injection problems. In gas or mist drilling, no radiation losses are included in the energy balance. No attempt is made to model flow in the formation. Average execution time is 50 CP seconds on a CDC CYBER170. This edition of GEOTEMP2 is designated as Version 2.0 by the contributors.« less

  9. Method for transferring thermal energy and electrical current in thin-film electrochemical cells

    DOE Patents [OSTI]

    Rouillard, Roger; Domroese, Michael K.; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Ranger, Michel; Sudano, Anthony; Trice, Jennifer L.; Turgeon, Thomas A.

    2003-05-27

    An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

  10. Advanced thermal barrier coatings for operation in high hydrogen content fueled gas turbines.

    SciTech Connect (OSTI)

    Sampath, Sanjay

    2015-04-02

    The Center for Thermal Spray Research (CTSR) at Stony Brook University in partnership with its industrial Consortium for Thermal Spray Technology is investigating science and technology related to advanced metallic alloy bond coats and ceramic thermal barrier coatings for applications in the hot section of gasified coal-based high hydrogen turbine power systems. In conjunction with our OEM partners (GE and Siemens) and through strategic partnership with Oak Ridge National Laboratory (ORNL) (materials degradation group and high temperature materials laboratory), a systems approach, considering all components of the TBC (multilayer ceramic top coat, metallic bond coat & superalloy substrate) is being taken during multi-layered coating design, process development and subsequent environmental testing. Recent advances in process science and advanced in situ thermal spray coating property measurement enabled within CTSR has been incorporated for full-field enhancement of coating and process reliability. The development of bond coat processing during this program explored various aspects of processing and microstructure and linked them to performance. The determination of the bond coat material was carried out during the initial stages of the program. Based on tests conducted both at Stony Brook University as well as those carried out at ORNL it was determined that the NiCoCrAlYHfSi (Amdry) bond coats had considerable benefits over NiCoCrAlY bond coats. Since the studies were also conducted at different cycling frequencies, thereby addressing an associated need for performance under different loading conditions, the Amdry bond coat was selected as the material of choice going forward in the program. With initial investigations focused on the fabrication of HVOF bond coats and the performance of TBC under furnace cycle tests , several processing strategies were developed. Two-layered HVOF bond coats were developed to render optimal balance of density and surface roughness and resulted in improved TBC lifetimes. Processing based approaches of identifying optimal processing regimes deploying advanced in-situ coating property measurements and in-flight diagnostic tools were used to develop process maps for bond coats. Having established a framework for the bond coat processing using the HVOF process, effort were channeled towards fabrication of APS and VPS bond coats with the same material composition. Comparative evaluation of the three deposition processes with regard to their microstrcuture , surface profiles and TBC performance were carried out and provided valuable insights into factors that require concurrent consideration for the development of bond coats for advanced TBC systems. Over the course of this program several advancements were made on the development of durable thermal barrier coatings. Process optimization techniques were utilized to identify processing regimes for both conventional YSZ as well as other TBC compositions such as Gadolinium Zirconate and other Co-doped materials. Measurement of critical properties for these formed the initial stages of the program to identify potential challenges in their implementation as part of a TBC system. High temperature thermal conductivity measurements as well as sintering behavior of both YSZ and GDZ coatings were evaluated as part of initial efforts to undersand the influence of processing on coating properties. By effectively linking fundamental coating properties of fracture toughness and elastic modulus to the cyclic performance of coatings, a durability strategy for APS YSZ coatings was developed. In order to meet the goals of fabricating a multimaterial TBC system further research was carried out on the development of a gradient thermal conductivity model and the evaluation of sintering behavior of multimaterial coatings. Layer optimization for desired properties in the multimaterial TBC was achieved by an iterative feedback approach utilizing process maps and in-situ and ex-situ coating property sensors. Addressing the challenges pertaining to the integration of th

  11. LDRD final report on polyphosphaacetylenes, new hybrid conducting organic-inorganic materials

    SciTech Connect (OSTI)

    Jamison, G.M.; Loy, D.A.; Saunders, R.S.; Alam, T.M.

    1996-06-01

    Thermal, electrochemical and transition metal mediated reactions of phosphaacetylene monomers were conducted in attempts to form novel polyphosphaacetylenes as a new class of potentially electrically conducting polymers. Molecular modeling was used to simulate the molecular conformations of optimized, isolated oligomers to identify the proper monomeric repeat units for highly conjugated molecules. Electrodeposition of suitable monomers led to low molecular weight oligomers. Thermal polymerization of phosphaacetylene monomers bearing aromatic substituents ed to the formation of polyhedral cage oligomers. Under metathesis polymerization conditions the phosphaacetylene monomers form unique complexes via an unprecedented sequence of intermediates which suggest that metathesis to linear oligomers is achievable. Conductivity measurements on electrodeposited oligomers indicate modest electrical conductivity.

  12. Thermal Performance Benchmarking (Presentation)

    SciTech Connect (OSTI)

    Moreno, G.

    2014-11-01

    This project will benchmark the thermal characteristics of automotive power electronics and electric motor thermal management systems. Recent vehicle systems will be benchmarked to establish baseline metrics, evaluate advantages and disadvantages of different thermal management systems, and identify areas of improvement to advance the state-of-the-art.

  13. Thermal neutron detection system

    DOE Patents [OSTI]

    Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

    2000-01-01

    According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

  14. Analysis of Hydraulic Conductivity Calculations

    SciTech Connect (OSTI)

    Green, R.E.

    2003-01-06

    Equations by Marshall and by Millington and Quirk for calculating hydraulic conductivity from pore-size distribution data are dependent on an arbitrary choice of the exponent on the porosity term and a correct estimate of residual water. This study showed that a revised equation, based on the pore-interaction model of Marshall, accurately predicts hydraulic conductivity for glass beads and a loam soil from the pressure-water content relationships of these porous materials.

  15. A steady state thermal duct model derived by fin-theory approach and applied on an unglazed solar collector

    SciTech Connect (OSTI)

    Stojanovic, B.; Hallberg, D.; Akander, J.

    2010-10-15

    This paper presents the thermal modelling of an unglazed solar collector (USC) flat panel, with the aim of producing a detailed yet swift thermal steady-state model. The model is analytical, one-dimensional (1D) and derived by a fin-theory approach. It represents the thermal performance of an arbitrary duct with applied boundary conditions equal to those of a flat panel collector. The derived model is meant to be used for efficient optimisation and design of USC flat panels (or similar applications), as well as detailed thermal analysis of temperature fields and heat transfer distributions/variations at steady-state conditions; without requiring a large amount of computational power and time. Detailed surface temperatures are necessary features for durability studies of the surface coating, hence the effect of coating degradation on USC and system performance. The model accuracy and proficiency has been benchmarked against a detailed three-dimensional Finite Difference Model (3D FDM) and two simpler 1D analytical models. Results from the benchmarking test show that the fin-theory model has excellent capabilities of calculating energy performances and fluid temperature profiles, as well as detailed material temperature fields and heat transfer distributions/variations (at steady-state conditions), while still being suitable for component analysis in junction to system simulations as the model is analytical. The accuracy of the model is high in comparison to the 3D FDM (the prime benchmark), as long as the fin-theory assumption prevails (no 'or negligible' temperature gradient in the fin perpendicularly to the fin length). Comparison with the other models also shows that when the USC duct material has a high thermal conductivity, the cross-sectional material temperature adopts an isothermal state (for the assessed USC duct geometry), which makes the 1D isothermal model valid. When the USC duct material has a low thermal conductivity, the heat transfer course of events adopts a 1D heat flow that reassembles the conditions of the 1D simple model (for the assessed USC duct geometry); 1D heat flow through the top and bottom fins/sheets as the duct wall reassembles a state of adiabatic condition. (author)

  16. Experimental study of the proposed super-thermal-conductor: BAs

    SciTech Connect (OSTI)

    Lv, Bing; Lan, Yucheng; Zhang, Qian; Ren, Zhifeng E-mail: cwchu@uh.edu; Wang, Xiqu; Jacobson, Allan J.; Hu, Yongjie; Chen, Gang; Broido, David; Chu, Ching-Wu E-mail: cwchu@uh.edu

    2015-02-16

    Recent calculations predict a super-thermal-conductivity of ?2000?Wm{sup ?1} K{sup ?1}, comparable to that of diamond, in cubic boron arsenide (BAs) crystals, which may offer inexpensive insulators with super-thermal-conductivity for microelectronic device applications. We have synthesized and characterized single crystals of BAs with a zinc blende cubic structure and lattice parameters of a?=?4.7830(7) . A relatively high thermal conductivity of ?200?Wm{sup ?1} K{sup ?1} is obtained, close to those of best non-carbon crystal insulators, such as SiC, although still an order of magnitude smaller than the value predicted. Based on our XPS, X-ray single crystal diffraction, and Raman scattering results, steps to achieve the predicted super-thermal conductivity in BAs are proposed.

  17. Underground Thermal Energy Storage (UTES) Via Borehole and Aquifer...

    Energy Savers [EERE]

    Conductivity Test (LTCT) or Distributed Thermal Response Test (DTRT) * Marines Corps Logistics Base, Albany GA (MCLB) * 110 m u-bend borehole heat exchanger * A 72 hours LTCT was...

  18. Characterization and modeling of thermal diffusion and aggregation in nanofluids.

    SciTech Connect (OSTI)

    Gharagozloo, Patricia E.; Goodson, Kenneth E.

    2010-05-01

    Fluids with higher thermal conductivities are sought for fluidic cooling systems in applications including microprocessors and high-power lasers. By adding high thermal conductivity nanoscale metal and metal oxide particles to a fluid the thermal conductivity of the fluid is enhanced. While particle aggregates play a central role in recent models for the thermal conductivity of nanofluids, the effect of particle diffusion in a temperature field on the aggregation and transport has yet to be studied in depth. The present work separates the effects of particle aggregation and diffusion using parallel plate experiments, infrared microscopy, light scattering, Monte Carlo simulations, and rate equations for particle and heat transport in a well dispersed nanofluid. Experimental data show non-uniform temporal increases in thermal conductivity above effective medium theory and can be well described through simulation of the combination of particle aggregation and diffusion. The simulation shows large concentration distributions due to thermal diffusion causing variations in aggregation, thermal conductivity and viscosity. Static light scattering shows aggregates form more quickly at higher concentrations and temperatures, which explains the increased enhancement with temperature reported by other research groups. The permanent aggregates in the nanofluid are found to have a fractal dimension of 2.4 and the aggregate formations that grow over time are found to have a fractal dimension of 1.8, which is consistent with diffusion limited aggregation. Calculations show as aggregates grow the viscosity increases at a faster rate than thermal conductivity making the highly aggregated nanofluids unfavorable, especially at the low fractal dimension of 1.8. An optimum nanoparticle diameter for these particular fluid properties is calculated to be 130 nm to optimize the fluid stability by reducing settling, thermal diffusion and aggregation.

  19. Thermal conductor for high-energy electrochemical cells

    DOE Patents [OSTI]

    Hoffman, Joseph A.; Domroese, Michael K.; Lindeman, David D.; Radewald, Vern E.; Rouillard, Roger; Trice, Jennifer L.

    2000-01-01

    A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

  20. Gradient Plasticity Model and its Implementation into MARMOT

    SciTech Connect (OSTI)

    Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.; Sun, Xin

    2013-08-01

    The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in this model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.

  1. Density gradient effects on transverse shear driven lower hybrid waves

    SciTech Connect (OSTI)

    DuBois, Ami M.; Thomas, Edward; Amatucci, William E.; Ganguli, Gurudas

    2014-06-15

    Shear driven instabilities are commonly observed in the near-Earth space, particularly in boundary layer plasmas. When the shear scale length (L{sub E}) is much less than the ion gyro-radius (?{sub i}) but greater than the electron gyro-radius (?{sub e}), the electrons are magnetized in the shear layer, but the ions are effectively un-magnetized. The resulting shear driven instability, the electron-ion hybrid (EIH) instability, is investigated in a new interpenetrating plasma configuration in the Auburn Linear EXperiment for Instability Studies. In order to understand the dynamics of magnetospheric boundary layers, the EIH instability is studied in the presence of a density gradient located at the boundary layer between two plasmas. This paper reports on a recent experiment in which electrostatic lower hybrid waves are identified as the EIH instability, and the effect of a density gradient on the instability properties are investigated.

  2. Fabrication process for a gradient index x-ray lens

    DOE Patents [OSTI]

    Bionta, R.M.; Makowiecki, D.M.; Skulina, K.M.

    1995-01-17

    A process is disclosed for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments in the soft x-ray region. 13 figures.

  3. Fabrication process for a gradient index x-ray lens

    DOE Patents [OSTI]

    Bionta, Richard M. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA); Skulina, Kenneth M. (Livermore, CA)

    1995-01-01

    A process for fabricating high efficiency x-ray lenses that operate in the 0.5-4.0 keV region suitable for use in biological imaging, surface science, and x-ray lithography of integrated circuits. The gradient index x-ray optics fabrication process broadly involves co-sputtering multi-layers of film on a wire, followed by slicing and mounting on block, and then ion beam thinning to a thickness determined by periodic testing for efficiency. The process enables the fabrication of transmissive gradient index x-ray optics for the 0.5-4.0 keV energy range. This process allows the fabrication of optical elements for the next generation of imaging and x-ray lithography instruments m the soft x-ray region.

  4. Radiography to measure the longitudinal density gradients of Pd compacts

    SciTech Connect (OSTI)

    Back, D.D.

    1992-05-14

    This study used radiography to detect and quantify density gradients in green compacts of Palladium powder. Ultrasonic velocity measurements had been tried previously, but they were affected by material properties, in addition to the density, so that an alternative was sought. The alternative technique used radiographic exposures of a series of standard compacts whose density is known and correlated with the radiographic film density. These correlations are used to predict the density in subsequent compacts.

  5. Gradient instabilities of electromagnetic waves in Hall thruster plasma

    SciTech Connect (OSTI)

    Tomilin, Dmitry

    2013-04-15

    This paper presents a linear analysis of gradient plasma instabilities in Hall thrusters. The study obtains and analyzes the dispersion equation of high-frequency electromagnetic waves based on the two-fluid model of a cold plasma. The regions of parameters corresponding to unstable high frequency modes are determined and the dependence of the increments and intrinsic frequencies on plasma parameters is obtained. The obtained results agree with those of previously published studies.

  6. Conductive Channel for Energy Transmission

    SciTech Connect (OSTI)

    Apollonov, Victor V. [A.M. Prokhorov General Physics Institute, Vavilov Str. 38, Moscow, 119991 (Russian Federation)

    2011-11-10

    For many years the attempts to create conductive channels of big length were taken in order to study the upper atmosphere and to settle special tasks, related to energy transmission. There upon the program of creation of 'Impulsar' represents a great interest, as this program in a combination with high-voltage high repetition rate electrical source can be useful to solve the above mentioned problems (N. Tesla ideas for the days of high power lasers). The principle of conductive channel production can be shortly described as follows. The 'Impulsar' - laser jet engine vehicle - propulsion take place under the influence of powerful high repetition rate pulse-periodic laser radiation. In the experiments the CO{sub 2}-laser and solid state Nd:YAG laser systems had been used. Active impulse appears thanks to air breakdown (<30 km) or to the breakdown of ablated material on the board (>30 km), placed in the vicinity of the focusing mirror-acceptor of the breakdown waves. With each pulse of powerful laser the device rises up, leaving a bright and dense trace of products with high degree of ionization and metallization by conductive nano-particles due to ablation. Conductive dust plasma properties investigation in our experiments was produced by two very effective approaches: high power laser controlled ablation and by explosion of wire. Experimental and theoretical results of conductive canal modeling will be presented. The estimations show that with already experimentally demonstrated figures of specific thrust impulse the lower layers of the Ionosphere can be reached in several ten seconds that is enough to keep the high level of channel conductivity and stability with the help of high repetition rate high voltage generator. Some possible applications for new technology are highlighted.

  7. Methods of conducting simultaneous exothermic and endothermic reactions

    DOE Patents [OSTI]

    Tonkovich, Anna Lee; Roberts, Gary L.; Perry, Steven T.; Fitzgerald, Sean P.

    2005-11-29

    Integrated Combustion Reactors (ICRs) and methods of making ICRs are described in which combustion chambers (or channels) are in direct thermal contact to reaction chambers for an endothermic reaction. Superior results were achieved for combustion chambers which contained a gap for free flow through the chamber. Particular reactor designs are also described. Processes of conducting reactions in integrated combustion reactors are described and results presented. Some of these processes are characterized by unexpected and superior results.

  8. Atmospheric gradients and the stability of expanding jets. [Astrophysics

    SciTech Connect (OSTI)

    Hardee, P.E.; Koupelis, T.; Norman, M.L.; Clarke, D.A. Illinois, University, Urbana )

    1991-05-01

    Numerical simulations of adiabatically expanding slab jets in initial static pressure balance with an external atmosphere have been performed and compared to predictions made by a linear analysis of the stability of expanding jets. It is found that jets are stabilized by jet expansion as predicted by the linear analysis. It is also found that an expanding jet can be destabilized by a positive temperature gradient or temperature jump in the surrounding medium which lowers the Mach number defined by the external sound speed. A temperature gradient or jump is more destabilizing than would be predicted by a linear stability analysis. The enhanced instability compared to an isothermal atmosphere with identical pressure gradient is a result of the reduced external Mach number and a result of a higher jet density relative to the density in the external medium and higher ram speed. Other differences between predictions made by the linear theory and the simulations can be understood qualitatively as a result of a change in wave speed as the wave amplitude increases. 12 refs.

  9. Lithium ion conducting ionic electrolytes

    DOE Patents [OSTI]

    Angell, C. Austen (Mesa, AZ); Xu, Kang (Tempe, AZ); Liu, Changle (Tulsa, OK)

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors.

  10. Lithium ion conducting ionic electrolytes

    DOE Patents [OSTI]

    Angell, C.A.; Xu, K.; Liu, C.

    1996-01-16

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

  11. Conducting Polymers for Neutron Detection

    SciTech Connect (OSTI)

    Kimblin, Clare; Miller, Kirk; Vogel, Bob; Quam, Bill; McHugh, Harry; Anthony, Glen; Mike, Grover

    2007-12-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number.

  12. Thermal transfer structures coupling electronics card(s) to coolant-cooled structure(s)

    DOE Patents [OSTI]

    David, Milnes P; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Parida, Pritish R; Schmidt, Roger R

    2014-12-16

    Cooling apparatuses and coolant-cooled electronic systems are provided which include thermal transfer structures configured to engage with a spring force one or more electronics cards with docking of the electronics card(s) within a respective socket(s) of the electronic system. A thermal transfer structure of the cooling apparatus includes a thermal spreader having a first thermal conduction surface, and a thermally conductive spring assembly coupled to the conduction surface of the thermal spreader and positioned and configured to reside between and physically couple a first surface of an electronics card to the first surface of the thermal spreader with docking of the electronics card within a socket of the electronic system. The thermal transfer structure is, in one embodiment, metallurgically bonded to a coolant-cooled structure and facilitates transfer of heat from the electronics card to coolant flowing through the coolant-cooled structure.

  13. Electrically conductive rigid polyurethane foam

    DOE Patents [OSTI]

    Neet, T.E.; Spieker, D.A.

    1983-12-08

    A rigid, moldable polyurethane foam comprises about 2 to 10 weight percent, based on the total foam weight, of a carbon black which is CONDUCTEX CC-40-220 or CONDUCTEX SC, whereby the rigid polyurethane foam is electrically conductive and has essentially the same mechanical properties as the same foam without carbon black added.

  14. Thin film ion conducting coating

    DOE Patents [OSTI]

    Goldner, Ronald B. (Lexington, MA); Haas, Terry (Sudbury, MA); Wong, Kwok-Keung (Watertown, MA); Seward, George (Arlington, MA)

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  15. Electrically conductive rigid polyurethane foam

    DOE Patents [OSTI]

    Neet, Thomas E. (Grandview, MO); Spieker, David A. (Olathe, KS)

    1985-03-19

    A rigid, polyurethane foam comprises about 2-10 weight percent, based on the total foam weight, of a carbon black which is CONDUCTEX CC-40-220 or CONDUCTEX SC, whereby the rigid polyurethane foam is electrically conductive and has essentially the same mechanical properties as the same foam without carbon black added.

  16. Catalytic thermal barrier coatings

    DOE Patents [OSTI]

    Kulkarni, Anand A. (Orlando, FL); Campbell, Christian X. (Orlando, FL); Subramanian, Ramesh (Oviedo, FL)

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  17. Nonequilibrium thermal entanglement

    SciTech Connect (OSTI)

    Quiroga, Luis; Rodriguez, Ferney J.; Ramirez, Maria E.; Paris, Roberto

    2007-03-15

    Results on heat current, entropy production rate, and entanglement are reported for a quantum system coupled to two different temperature heat reservoirs. By applying a temperature gradient, different quantum states can be found with exactly the same amount of entanglement but different purity degrees and heat currents. Furthermore, a nonequilibrium enhancement-suppression transition behavior of the entanglement is identified.

  18. Scattering Solar Thermal Concentrators

    Office of Environmental Management (EM)

    sunshot DOEGO-102012-3669 * September 2012 MOTIVATION All thermal concentrating solar power (CSP) systems use solar tracking, which involves moving large mirror surfaces...

  19. Battery Thermal Characterization

    SciTech Connect (OSTI)

    Saxon, Aron; Powell, Mitchell; Shi, Ying

    2015-06-09

    This presentation provides an update of NREL's battery thermal characterization efforts for the 2015 U.S. Department of Energy Annual Merit Reviews.

  20. Sandia Thermal Program

    Energy Science and Technology Software Center (OSTI)

    2005-11-23

    Thermal analysis in 1-D planar, cylindrical and spherical geometries using control volume finite element spatial discretization with 1st and 2nd order implicit time integrators.

  1. R655-1-8 Temperature Gradient Wells | Open Energy Information

    Open Energy Info (EERE)

    R655-1-8 Temperature Gradient Wells Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- RegulationRegulation: R655-1-8 Temperature Gradient...

  2. Dynamic Mechanical Thermal Analysis of Virgin TR-55 Silicone Rubber

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect Dynamic Mechanical Thermal Analysis of Virgin TR-55 Silicone Rubber Citation Details In-Document Search Title: Dynamic Mechanical Thermal Analysis of Virgin TR-55 Silicone Rubber Dynamic mechanical thermal analysis (DMTA) of virgin TR-55 silicone rubber specimens was conducted. Dynamic frequency/temperature sweep tests were conducted over the ranges 0.1-100 rad/s and 30-100 C using a parallel plate test geometry. A strain of 0.2% was used, which was near

  3. Thermal-mechanical stability of single crystal oxide refractive concentrators for high-temperature solar thermal propulsion

    SciTech Connect (OSTI)

    Zhu, D.; Jacobson, S.; Miller, R.A.

    1999-07-01

    Single crystal oxides such as yttria-stabilized zirconia (Y{sub 2}O{sub 3}-ZrO{sub 2}), yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}, or YAG), magnesium oxide (MgO) and sapphire (Al{sub 2}O{sub 3}) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO{sub 2} laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet and magnesium oxide.

  4. Up-gradient particle flux in a drift wave-zonal flow system

    SciTech Connect (OSTI)

    Cui, L.; Tynan, G. R.; Thakur, S. C.; Diamond, P. H.; Brandt, C.

    2015-05-15

    We report a net inward, up-gradient turbulent particle flux in a cylindrical plasma when collisional drift waves generate a sufficiently strong sheared azimuthal flow that drives positive (negative) density fluctuations up (down) the background density gradient, resulting in a steepening of the mean density gradient. The results show the existence of a saturation mechanism for drift-turbulence driven sheared flows that can cause up-gradient particle transport and density profile steepening.

  5. Conduction at a ferroelectric interface

    SciTech Connect (OSTI)

    Marshall, Matthew S. J.; Malashevich, Andrei; Disa, Ankit S.; Han, Myung -Geun; Chen, Hanghui; Zhu, Yimei; Ismail-Beigi, Sohrab; Walker, Frederick J.; Ahn, Charles H.

    2014-11-05

    Typical logic elements utilizing the field effect rely on the change in carrier concentration due to the field in the channel region of the device. Ferroelectric-field-effect devices provide a nonvolatile version of this effect due to the stable polarization order parameter in the ferroelectric. In this study, we describe an oxide/oxide ferroelectric heterostructure device based on (001)-oriented PbZr??.?Ti?.?O?-LaNiO? where the dominant change in conductivity is a result of a significant mobility change in the interfacial channel region. The effect is confined to a few atomic layers at the interface and is reversible by switching the ferroelectric polarization. More interestingly, in one polarization state, the field effect induces a 1.7 eV shift of the interfacial bands to create a new conducting channel in the interfacial PbO layer of the ferroelectric.

  6. Conduction at a ferroelectric interface

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Marshall, Matthew S. J.; Malashevich, Andrei; Disa, Ankit S.; Han, Myung -Geun; Chen, Hanghui; Zhu, Yimei; Ismail-Beigi, Sohrab; Walker, Frederick J.; Ahn, Charles H.

    2014-11-05

    Typical logic elements utilizing the field effect rely on the change in carrier concentration due to the field in the channel region of the device. Ferroelectric-field-effect devices provide a nonvolatile version of this effect due to the stable polarization order parameter in the ferroelectric. In this study, we describe an oxide/oxide ferroelectric heterostructure device based on (001)-oriented PbZr₀̣.₂Ti₀.₈O₃-LaNiO₃ where the dominant change in conductivity is a result of a significant mobility change in the interfacial channel region. The effect is confined to a few atomic layers at the interface and is reversible by switching the ferroelectric polarization. More interestingly, inmore » one polarization state, the field effect induces a 1.7 eV shift of the interfacial bands to create a new conducting channel in the interfacial PbO layer of the ferroelectric.« less

  7. Conduction at a ferroelectric interface

    SciTech Connect (OSTI)

    Marshall, Matthew S. J.; Malashevich, Andrei; Disa, Ankit S.; Han, Myung-Guen; Chen, Hanghui; Zhu, Yimei; Ismail-Beigi, Sohrab; Walker, Frederick J.; Ahn, Charles H.

    2014-11-05

    Typical logic elements utilizing the field effect rely on the change in carrier concentration due to the field in the channel region of the device. Ferroelectric-field-effect devices provide a nonvolatile version of this effect due to the stable polarization order parameter in the ferroelectric. In this work, we describe an oxide/ oxide ferroelectric heterostructure device based on (001)-oriented PbZr??.?Ti?.?O?-LaNiO? where the dominant change in conductivity is a result of a significant mobility change in the interfacial channel region. The effect is confined to a few atomic layers at the interface and is reversible by switching the ferroelectric polarization. More interestingly, in one polarization state, the field effect induces a 1.7-eV shift of the interfacial bands to create a new conducting channel in the interfacial PbO layer of the ferroelectric.

  8. Electrically conductive polymer concrete coatings

    DOE Patents [OSTI]

    Fontana, J.J.; Elling, D.; Reams, W.

    1988-05-26

    A sprayable electrically conductive polymer concrete coating for vertical and overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt% calcined coke breeze, 40 wt% vinyl ester resin with 3.5 wt% modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag. 4 tabs.

  9. Electrically conductive polymer concrete coatings

    DOE Patents [OSTI]

    Fontana, Jack J. (Shirley, NY); Elling, David (Centereach, NY); Reams, Walter (Shirley, NY)

    1990-01-01

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  10. Planning and Conducting Readiness Reviews

    Energy Savers [EERE]

    3006-2010 ________________________ Superseding DOE-STD-3006-2000 June 2000 DOE STANDARD PLANNING AND CONDUCTING READINESS REVIEWS U.S. Department of Energy AREA OPER Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. TS This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from ES&H Technical Information Services, U.S. Department of Energy, (800) 473-4375, fax: (301) 903-9823.

  11. Electrically conductive polymer concrete coatings

    DOE Patents [OSTI]

    Fontana, J.J.; Elling, D.; Reams, W.

    1990-03-13

    A sprayable electrically conductive polymer concrete coating for vertical d overhead applications is described. The coating is permeable yet has low electrical resistivity (<10 ohm-cm), good bond strength to concrete substrates, and good weatherability. A preferred formulation contains about 60 wt % calcined coke breeze, 40 wt % vinyl ester with 3.5 wt % modified bentonite clay. Such formulations apply evenly and provide enough rigidity for vertical or overhead structures so there is no drip or sag.

  12. Hydraulic Conductivity Measurements Barrow 2014

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Katie McKnight; Tim Kneafsey; Craig Ulrich; Jil Geller

    2015-02-22

    Six individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, in May of 2013 as part of the Next Generation Ecosystem Experiment (NGEE). Each core was drilled from a different location at varying depths. A few days after drilling, the cores were stored in coolers packed with dry ice and flown to Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA. 3-dimensional images of the cores were constructed using a medical X-ray computed tomography (CT) scanner at 120kV. Hydraulic conductivity samples were extracted from these cores at LBNL Richmond Field Station in Richmond, CA, in February 2014 by cutting 5 to 8 inch segments using a chop saw. Samples were packed individually and stored at freezing temperatures to minimize any changes in structure or loss of ice content prior to analysis. Hydraulic conductivity was determined through falling head tests using a permeameter [ELE International, Model #: K-770B]. After approximately 12 hours of thaw, initial falling head tests were performed. Two to four measurements were collected on each sample and collection stopped when the applied head load exceeded 25% change from the original load. Analyses were performed between 2 to 3 times for each sample. The final hydraulic conductivity calculations were computed using methodology of Das et al., 1985.

  13. One-Dimensional Heat Conduction

    Energy Science and Technology Software Center (OSTI)

    1992-03-09

    ICARUS-LLNL was developed to solve one-dimensional planar, cylindrical, or spherical conduction heat transfer problems. The IBM PC version is a family of programs including ICARUSB, an interactive BASIC heat conduction program; ICARUSF, a FORTRAN heat conduction program; PREICAR, a BASIC preprocessor for ICARUSF; and PLOTIC and CPLOTIC, interpretive BASIC and compiler BASIC plot postprocessor programs. Both ICARUSB and ICARUSF account for multiple material regions and complex boundary conditions, such as convection or radiation. In addition,more » ICARUSF accounts for temperature-dependent material properties and time or temperature-dependent boundary conditions. PREICAR is a user-friendly preprocessor used to generate or modify ICARUSF input data. PLOTIC and CPLOTIC generate plots of the temperature or heat flux profile at specified times, plots of the variation of temperature or heat flux with time at selected nodes, or plots of the solution grid. First developed in 1974 to allow easy modeling of complex one-dimensional systems, its original application was in the nuclear explosive testing program. Since then it has undergone extensive revision and been applied to problems dealing with laser fusion target fabrication, heat loads on underground tests, magnetic fusion switching tube anodes, and nuclear waste isolation canisters.« less

  14. Hydraulic Conductivity Measurements Barrow 2014

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Katie McKnight; Tim Kneafsey; Craig Ulrich; Jil Geller

    Six individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, in May of 2013 as part of the Next Generation Ecosystem Experiment (NGEE). Each core was drilled from a different location at varying depths. A few days after drilling, the cores were stored in coolers packed with dry ice and flown to Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA. 3-dimensional images of the cores were constructed using a medical X-ray computed tomography (CT) scanner at 120kV. Hydraulic conductivity samples were extracted from these cores at LBNL Richmond Field Station in Richmond, CA, in February 2014 by cutting 5 to 8 inch segments using a chop saw. Samples were packed individually and stored at freezing temperatures to minimize any changes in structure or loss of ice content prior to analysis. Hydraulic conductivity was determined through falling head tests using a permeameter [ELE International, Model #: K-770B]. After approximately 12 hours of thaw, initial falling head tests were performed. Two to four measurements were collected on each sample and collection stopped when the applied head load exceeded 25% change from the original load. Analyses were performed between 2 to 3 times for each sample. The final hydraulic conductivity calculations were computed using methodology of Das et al., 1985.

  15. A dislocation-based, straingradientplasticity strengthening model for deformation processed metalmetal composites

    SciTech Connect (OSTI)

    Tian, Liang; Russell, Alan; Anderson, Iver

    2014-01-03

    Deformation processed metalmetal composites (DMMCs) are high-strength, high-electrical conductivity composites developed by severe plastic deformation of two ductile metal phases. The extraordinarily high strength of DMMCs is underestimated using the rule of mixture (or volumetric weighted average) of conventionally work-hardened metals. A dislocation-density-based, straingradientplasticity model is proposed to relate the strain-gradient effect with the geometrically necessary dislocations emanating from the interface to better predict the strength of DMMCs. The model prediction was compared with our experimental findings of CuNb, CuTa, and AlTi DMMC systems to verify the applicability of the new model. The results show that this model predicts the strength of DMMCs better than the rule-of-mixture model. The strain-gradient effect, responsible for the exceptionally high strength of heavily cold worked DMMCs, is dominant at large deformation strain since its characteristic microstructure length is comparable with the intrinsic material length.

  16. SLIM, Short-pulse Technology for High Gradient Induction Accelerators

    SciTech Connect (OSTI)

    Arntz, Floyd; Kardo-Sysoev, A.; Krasnykh, A.; /SLAC

    2008-12-16

    A novel short-pulse concept (SLIM) suited to a new generation of a high gradient induction particle accelerators is described herein. It applies advanced solid state semiconductor technology and modern microfabrication techniques to a coreless induction method of charged particle acceleration first proven on a macro scale in the 1960's. Because this approach avoids use of magnetic materials there is the prospect of such an accelerator working efficiently with accelerating pulses in the nanosecond range and, potentially, at megahertz pulse rates. The principal accelerator section is envisioned as a stack of coreless induction cells, the only active element within each being a single, extremely fast (subnanosecond) solid state opening switch: a Drift Step Recovery Diode (DSRD). Each coreless induction cell incorporates an electromagnetic pulse compressor in which inductive energy developed within a transmission-line feed structure over a period of tens of nanoseconds is diverted to the acceleration of the passing charge packet for a few nanoseconds by the abrupt opening of the DSRD switch. The duration of this accelerating output pulse--typically two-to-four nanoseconds--is precisely determined by a microfabricated pulse forming line connected to the cell. Because the accelerating pulse is only nanoseconds in duration, longitudinal accelerating gradients approaching 100 MeV per meter are believed to be achievable without inciting breakdown. Further benefits of this approach are that, (1) only a low voltage power supply is required to produce the high accelerating gradient, and, (2) since the DSRD switch is normally closed, voltage stress is limited to a few nanoseconds per period, hence the susceptibility to hostile environment conditions such as ionizing radiation, mismatch (e.g. in medical applications the peak beam current may be low), strong electromagnetic noise levels, etc is expected to be minimal. Finally, we observe the SLIM concept is not limited to linac applications; for instance, it could be employed to both accelerate the beam and to stabilize the superbunch mode of operation in circular track machines.

  17. Electron geodesic acoustic modes in electron temperature gradient mode turbulence

    SciTech Connect (OSTI)

    Anderson, Johan; Nordman, Hans [Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Singh, Raghvendra; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-08-15

    In this work, the first demonstration of an electron branch of the geodesic acoustic mode (el-GAM) driven by electron temperature gradient (ETG) modes is presented. The work is based on a fluid description of the ETG mode retaining non-adiabatic ions and the dispersion relation for el-GAMs driven nonlinearly by ETG modes is derived. A new saturation mechanism for ETG turbulence through the interaction with el-GAMs is found, resulting in a significantly enhanced ETG turbulence saturation level compared to the mixing length estimate.

  18. Gradient index liquid crystal devices and method of fabrication thereof

    DOE Patents [OSTI]

    Lee, Jae-Cheul (Rochester, NY); Jacobs, Stephen (Pittsford, NY)

    1991-01-01

    Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

  19. Gradient index liquid crystal devices and method of fabrication thereof

    DOE Patents [OSTI]

    Lee, J.C.; Jacobs, S.

    1991-10-29

    Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

  20. High and ulta-high gradient quadrupole magnets

    SciTech Connect (OSTI)

    Brunk, W.O.; Walz, D.R.

    1985-05-01

    Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

  1. Fabrication of high gradient insulators by stack compression

    DOE Patents [OSTI]

    Harris, John Richardson; Sanders, Dave; Hawkins, Steven Anthony; Norona, Marcelo

    2014-04-29

    Individual layers of a high gradient insulator (HGI) are first pre-cut to their final dimensions. The pre-cut layers are then stacked to form an assembly that is subsequently pressed into an HGI unit with the desired dimension. The individual layers are stacked, and alignment is maintained, using a sacrificial alignment tube that is removed after the stack is hot pressed. The HGI's are used as high voltage vacuum insulators in energy storage and transmission structures or devices, e.g. in particle accelerators and pulsed power systems.

  2. HIGH AVERAGE CURRENT LOW EMITTANCE BEAM EMPLOYING CW NORMAL CONDUCTING GUN.

    SciTech Connect (OSTI)

    CHANG,X.; BEN-ZVI, I.; KEWISCH, J.; PAI, C.

    2007-06-25

    CW normal conducting guns usually do not achieve very high field gradient and waste much RF power at high field gradient compared to superconducting cavities. But they have less trapped modes and wakefields compared to the superconducting cavities due to their low Q. The external bucking coil can also be applied very close to the cathode to improve the beam quality. By using a low frequency gun with a recessed cathode and a carefully designed beam line we can get a high average current and a high quality beam with acceptable RF power loss on the cavity wall. This paper shows that the CW normal conducting gun can be a backup solution for those projects which need high peak and average current, low emittance electron beams such as the Relativistic Heavy Ion Collider (RHIC) e-cooling project and Energy Recovery Linac (Em) project.

  3. Thermal treatment wall

    DOE Patents [OSTI]

    Aines, Roger D. (Livermore, CA); Newmark, Robin L. (Livermore, CA); Knauss, Kevin G. (Livermore, CA)

    2000-01-01

    A thermal treatment wall emplaced to perform in-situ destruction of contaminants in groundwater. Thermal destruction of specific contaminants occurs by hydrous pyrolysis/oxidation at temperatures achievable by existing thermal remediation techniques (electrical heating or steam injection) in the presence of oxygen or soil mineral oxidants, such as MnO.sub.2. The thermal treatment wall can be installed in a variety of configurations depending on the specific objectives, and can be used for groundwater cleanup, wherein in-situ destruction of contaminants is carried out rather than extracting contaminated fluids to the surface, where they are to be cleaned. In addition, the thermal treatment wall can be used for both plume interdiction and near-wellhead in-situ groundwater treatment. Thus, this technique can be utilized for a variety of groundwater contamination problems.

  4. Solar thermal aircraft

    DOE Patents [OSTI]

    Bennett, Charles L. (Livermore, CA)

    2007-09-18

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  5. Environmental impacts of ocean thermal energy conversion

    SciTech Connect (OSTI)

    Not Available

    1986-04-01

    Ocean thermal energy conversion (OTEC) is a promising technology for production of energy and usable by-products from solar-generated temperature gradients in the world's oceans. Although considered benign compared to alternative forms of energy generation, deployment of OTEC plants will result in interactions with marine, terrestrial, and atmospheric environments and in socioeconomic interactions with surrounding areas. The Ocean Energy Technology Program of the Department of Energy has funded research to improve the understanding of these interactions. No insurmountable environmental obstacle to OTEC deployment has been uncovered. This document contains a summary of that research for entrepreneurs, utility engineers, and others interested in pursuing OTEC's potential. In addition, it provides a guide to permits, regulations, and licenses applicable to construction of an OTEC plant.

  6. Conducting a school energy audit

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    CONDUCTING A SCHOOL ENERGY AUDIT Brad Boyle (High School) TYPES OF AUDITS:  (1) School Energy Audit  (2) Home Energy Audit in a Multi-Person Home  (3) Personal Energy Audit I focused on the school energy audit. This could be done in conjunction with a personal energy auit. SOURCES  NEED Resources http://www.need.org/files/curriculum/guides/Energy SurveyStudent.pdf Colorado State Energy Audit www.ext.colostate.edu/energy/k12/audit- lesson.pdf Colorado Green Schools

  7. Thermally robust semiconductor optical amplifiers and laser diodes

    DOE Patents [OSTI]

    Dijaili, Sol P. (Moraga, CA); Patterson, Frank G. (Danville, CA); Walker, Jeffrey D. (El Cerrito, CA); Deri, Robert J. (Pleasanton, CA); Petersen, Holly (Manteca, CA); Goward, William (Antioch, CA)

    2002-01-01

    A highly heat conductive layer is combined with or placed in the vicinity of the optical waveguide region of active semiconductor components. The thermally conductive layer enhances the conduction of heat away from the active region, which is where the heat is generated in active semiconductor components. This layer is placed so close to the optical region that it must also function as a waveguide and causes the active region to be nearly the same temperature as the ambient or heat sink. However, the semiconductor material itself should be as temperature insensitive as possible and therefore the invention combines a highly thermally conductive dielectric layer with improved semiconductor materials to achieve an overall package that offers improved thermal performance. The highly thermally conductive layer serves two basic functions. First, it provides a lower index material than the semiconductor device so that certain kinds of optical waveguides may be formed, e.g., a ridge waveguide. The second and most important function, as it relates to this invention, is that it provides a significantly higher thermal conductivity than the semiconductor material, which is the principal material in the fabrication of various optoelectronic devices.

  8. Method and apparatus for thermal management of vehicle exhaust systems

    DOE Patents [OSTI]

    Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

    1995-01-01

    A catalytic converter is surrounded by variable conductance insulation for maintaining the operating temperature of the catalytic converter at an optimum level, for inhibiting heat loss when raising catalytic converter temperature to light-off temperature, for storing excess heat to maintain or accelerate reaching light-off temperature, and for conducting excess heat away from the catalytic converter after reaching light-off temperature. The variable conductance insulation includes vacuum gas control and metal-to-metal thermal shunt mechanisms. Radial and axial shielding inhibits radiation and convection heat loss. Thermal storage media includes phase change material, and heat exchanger chambers and fluids carry heat to and from the catalytic converter.

  9. A linear helicon plasma device with controllable magnetic field gradient

    SciTech Connect (OSTI)

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2012-06-15

    Current free double layers (CFDLs) are localized potential structures having spatial dimensions - Debye lengths and potential drops of more than local electron temperature across them. CFDLs do not need a current for them to be sustained and hence they differ from the current driven double layers. Helicon antenna produced plasmas in an expanded chamber along with an expanding magnetic field have shown the existence of CFDL near the expansion region. A helicon plasma device has been designed, fabricated, and installed in the Institute for Plasma Research, India to study the role of maximum magnetic field gradient as well as its location with respect to the geometrical expansion region of the chamber in CFDL formation. The special feature of this machine consisting of two chambers of different radii is its capability of producing different magnetic field gradients near the physical boundary between the two chambers either by changing current in one particular coil in the direction opposite to that in other coils and/or by varying the position of this particular coil. Although, the machine is primarily designed for CFDL experiments, it is also capable of carrying out many basic plasma physics experiments such as wave propagation, wave coupling, and plasma instabilities in a varying magnetic field topology. In this paper, we will present the details of the machine construction, its specialties, and some preliminary results about the production and characterization of helicon plasma in this machine.

  10. Convective heat transfer with buoyancy effects from thermal sources on a flat plate

    SciTech Connect (OSTI)

    Tewari, S.S.; Jaluria, Y. )

    1991-06-01

    An experimental study is carried out on the thermal interaction between two finite-size heat sources, located on a flat plate that is well insulated on the back. Both the horizontal and the vertical orientations of the surface are studied by measuring the flow velocities, the temperature field, and the local heat flux. The investigation is directed at the pure natural convection circumstance (no forced flow velocity) and the buoyancy-dominated mixed-convection circumstance (presence of a relatively small forced flow velocity). Large temperature gradients occur in the vicinity of the heat sources, resulting in a substantial diffusion of heat along the plate length. However, the effect of conduction is found to be highly localized. The orientation of the surface has a very strong effect on the interaction of the wakes from the heat sources for the circumstances considered. An upstream source is found to have a very strong influence on the temperature of a downstream source in the vertical surface orientation but has a much weaker influence in the horizontal orientation. In the latter circumstance the presence of a small forced flow velocity may actually increase the temperature of a downstream source by tilting the wake from the upstream source toward the downstream source. 25 refs.

  11. Water-soluble conductive polymers

    DOE Patents [OSTI]

    Aldissi, Mahmoud (Sante Fe, NM)

    1990-01-01

    Polymers which are soluble in water and are electrically conductive. The monomer repeat unit is a thiophene or pyrrole molecule having an alkyl group substituted for the hydrogen atom located in the beta position of the thiophene or pyrrole ring and having a surfactant molecule at the end of the alkyl chain. Polymers of this class having 8 or more carbon atoms in the alkyl chain exhibit liquid crystalline behavior, resulting in high electrical anisotropy. The monomer-to-monomer bonds are located between the carbon atoms which are adjacent to the sulfur or nitrogen atoms. The number of carbon atoms in the alkyl group may vary from 1 to 20 carbon atoms. The surfactant molecule consists of a sulfonate group, or a sulfate group, or a carboxylate group, and hydrogen or an alkali metal. Negative ions from a supporting electrolyte which may be used in the electrochemical synthesis of a polymer may be incorporated into the polymer during the synthesis and serve as a dopant to increase the conductivity.

  12. Water-soluble conductive polymers

    DOE Patents [OSTI]

    Aldissi, Mahmoud (Sante Fe, NM)

    1989-01-01

    Polymers which are soluble in water and are electrically conductive. The monomer repeat unit is a thiophene or pyrrole molecule having an alkyl group substituted for the hydrogen atom located in the beta position of the thiophene or pyrrole ring and having a surfactant molecule at the end of the alkyl chain. Polymers of this class having 8 or more carbon atoms in the alkyl chain exhibit liquid crystalline behavior, resulting in high electrical anisotropy. The monomer-to-monomer bonds are located between the carbon atoms which are adjacent to the sulfur or nitrogen atoms. The number of carbon atoms in the alkyl group may vary from 1 to 20 carbon atoms. The surfactant molecule consists of a sulfonate group, or a sulfate group, or a carboxylate group, and hydrogen or an alkali metal. Negative ions from a supporting electrolyte which may be used in the electrochemical synthesis of a polymer may be incorporated into the polymer during the synthesis and serve as a dopant to increase the conductivity.

  13. Water-soluble conductive polymers

    DOE Patents [OSTI]

    Aldissi, M.

    1988-02-12

    Polymers which are soluble in water and are electrically conductive. The monomer repeat unit is a thiophene or pyrrole molecule having an alkyl group substituted for the hydrogen atom located in the beta position of the thiophene or pyrrole ring and having a surfactant molecule at the end of the alkyl chain. Polymers of this class having 8 or more carbon atoms in the alkyl chain exhibit liquid crystalline behavior, resulting in high electrical anisotropy. The monomer-to-monomer bonds are located between the carbon atoms which are adjacent to the sulfur or nitrogen atoms. The number of carbon atoms in the alkyl group may vary from 1 to 20 carbon atoms. The surfactant molecule consists of a sulfonate group, or a sulfate group, or a carboxylate group, and hydrogen or an alkali metal. Negative ions from a supporting electrolyte which may be used in the electrochemical synthesis of a polymer may be incorporated into the polymer during the synthesis and serve as a dopant to increase the conductivity.

  14. Thermally-related safety issues associated with thermal batteries.

    SciTech Connect (OSTI)

    Guidotti, Ronald Armand

    2006-06-01

    Thermal batteries can experience thermal runaway under certain usage conditions. This can lead to safety issues for personnel and cause damage to associated test equipment if the battery thermally self destructs. This report discusses a number of thermal and design related issues that can lead to catastrophic destruction of thermal batteries under certain conditions. Contributing factors are identified and mitigating actions are presented to minimize or prevent undesirable thermal runaway.

  15. Incinerator thermal release valve risk assessment

    SciTech Connect (OSTI)

    Stevens, J.B.

    1998-12-31

    Human health risk assessments were conducted on emissions from several types of incinerators--a hazardous waste combustor, a medical waste/tire combustor, and a refuse derived fuel combustor in three different states. As part of these studies, the short-term emissions from thermal release valves operating during upset conditions were additionally evaluated. The latter assessments addressed two specific risk-related questions: (1) what are the incremental long-term risks/hazards associated with these short-term emissions; (2) what are the acute health hazards associated with these emissions? For each study, emission estimates for both the incinerator stack and the thermal release valve were obtained from the facility. Stack testing was utilized to obtain stack gas concentrations of emissions at one facility; engineering estimates were used to ascertain emissions from the thermal release valve. The two facilities were proposed incinerators, so literature-derived emissions were used throughout.

  16. Transport properties of multicomponent thermal plasmas: Grad method versus Chapman-Enskog method

    SciTech Connect (OSTI)

    Porytsky, P. [Institute for Nuclear Research, 03680 Kyiv (Ukraine); Krivtsun, I.; Demchenko, V. [Paton Welding Institute, 03680 Kyiv (Ukraine); Reisgen, U.; Mokrov, O.; Zabirov, A. [RWTH Aachen University, ISF-Welding and Joining Institute, 52062 Aachen (Germany); Gorchakov, S.; Timofeev, A.; Uhrlandt, D. [Leibniz Institute for Plasma Science and Technology (INP Greifswald), 17489 Greifswald (Germany)

    2013-02-15

    Transport properties (thermal conductivity, viscosity, and electrical conductivity) for multicomponent Ar-Fe thermal plasmas at atmospheric pressure have been determined by means of two different methods. The transport coefficients set based on Grad's method is compared with the data obtained when using the Chapman-Enskog's method. Results from both applied methods are in good agreement. It is shown that the Grad method is suitable for the determination of transport properties of the thermal plasmas.

  17. Electrolytic decontamination of conductive materials

    SciTech Connect (OSTI)

    Nelson, T.O.; Campbell, G.M.; Parker, J.L.; Getty, R.H.; Hergert, T.R.; Lindahl, K.A.; Peppers, L.G.

    1993-10-01

    Using the electrolytic method, the authors have demonstrated removal of Pu from contaminated conductive material. At EG&G Rocky Flats, they electrolytically decontaminated stainless steel. Results from this work show removal of fixed contamination, including the following geometries: planar, large radius, bolt holes, glove ports, and protruding studs. More specifically, fixed contamination was reduced from levels ranging > 1,000,000 counts per minute (cpm) down to levels ranging from 1,500 to < 250 cpm with the electrolytic method. More recently, the electrolytic work has continued at LANL as a joint project with EG&G. Impressively, electrolytic decontamination experiments on removal of Pu from oralloy coupons have shown decreases in swipable contamination that initially ranged from 500,000 to 1,500,000 disintegrations per minute (dpm) down to 0--2 dpm.

  18. Multilayer thermal barrier coating systems

    DOE Patents [OSTI]

    Vance, Steven J. (Orlando, FL); Goedjen, John G. (Oviedo, FL); Sabol, Stephen M. (Orlando, FL); Sloan, Kelly M. (Longwood, FL)

    2000-01-01

    The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

  19. Status of High Power Tests of Normal Conducting Single-Cell Structures

    SciTech Connect (OSTI)

    Dolgashev, V.A.; Tantawi, S.G.; Higashi, Y.; Higo, T.; /KEK, Tsukuba

    2011-11-04

    We report the results of ongoing high power tests of single-cell standing wave structures. These tests are part of an experimental and theoretical study of rf breakdown in normal conducting structures at 11.4 GHz. The goal of this study is to determine the maximum gradient possibilities for normal-conducting rf powered particle beam accelerators. The test setup consists of reusable mode launchers and short test structures powered by SLACs XL-4 klystron. The mode launchers and structures were manufactured at SLAC and KEK and tested at the SLAC klystron test laboratory.

  20. Numerical Model for Conduction-Cooled Current Lead Heat Loads

    SciTech Connect (OSTI)

    White, M.J.; Wang, X.L.; Brueck, H.D.; /DESY

    2011-06-10

    Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. In addition, the XFEL (X-Ray Free Electron Laser) prototype current leads are modeled and compared to the experimental results from testing at DESY's XFEL Magnet Test Stand (XMTS) and Cryomodule Test Bench (CMTB).