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1

Low Conductivity Thermal Barrier Coatings  

E-Print Network [OSTI]

Low Conductivity Thermal Barrier Coatings A Dissertation Presented to The Faculty of the School conductivity of the coatings. The minimum thermal conductivity occurs at a low rotation rate and is 0.8 W intrinsic thermal conductivity, good phase stability and greater resistance to sintering and CMAS attack

Wadley, Haydn

2

Enhanced Thermal Conductivity Oxide Fuels  

SciTech Connect (OSTI)

the purpose of this project was to investigate the feasibility of increasing the thermal conductivity of oxide fuels by adding small fractions of a high conductivity solid phase.

Alvin Solomon; Shripad Revankar; J. Kevin McCoy

2006-01-17T23:59:59.000Z

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

Effective Thermal Conductivity of Graded Nanocomposites with Interfacial Thermal  

E-Print Network [OSTI]

.M. Yin", G. H. Paulino", W.G. Buttlar", and L.Z. Sun'' '^Department of Civil and Environmental the effective thermal conductivity distribution in functionally graded materials (FGMs) considering the Kapitza is developed to derive the averaged heat flux field of the particle phase. Then the temperature gradient can

Paulino, Glaucio H.

5

Thermal Gradient Holes | Open Energy Information  

Open Energy Info (EERE)

Thermal Gradient Holes Thermal Gradient Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Thermal Gradient Holes Details Activities (50) Areas (39) Regions (4) NEPA(29) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Field wide fluid flow characteristics if an array of wells are drilled Thermal: Mapping and projecting thermal anomalies Cost Information Low-End Estimate (USD): 5.00500 centUSD 0.005 kUSD 5.0e-6 MUSD 5.0e-9 TUSD / foot Median Estimate (USD): 16.501,650 centUSD 0.0165 kUSD 1.65e-5 MUSD 1.65e-8 TUSD / foot High-End Estimate (USD): 50.005,000 centUSD

6

Thermal conductivity of a kinetic ising model  

Science Journals Connector (OSTI)

Using a novel extension of the microcanonical Monte Carlo algorithm, we have simulated the behavior of a two-dimensional nearest-neighbor ferromagnetic Ising model in the presence of a temperature gradient. The technique consists of setting the temperatures of boundary spins, while allowing "demons" associated with the other sites to control heat transfer. We demonstrate that our system is in local thermodynamic equilibrium, and compute the thermal conductivity as a function of temperature.

R. Harris and Martin Grant

1988-11-01T23:59:59.000Z

7

Cylindrical thermal contact conductance  

E-Print Network [OSTI]

of the Mahr-Federal, Inc. respectively facilitated and provided the necessary surface metrology data of the test pieces. Mr. Claude Davis of Corning, Inc. obtained the thermophysical properties of the Ultra Low Expansion Titanium Silicate glass used... as thermal expansion standard. The engineers at National Instruments provided some much-needed advice and software for programming the data acquisition system. The TAMU Physics Machine Shop provided design advice and a couple of last...

Ayers, George Harold

2004-09-30T23:59:59.000Z

8

Determination of thermal conductivity and formation temperature from cooling history of friction-heated probes  

Science Journals Connector (OSTI)

......of geothermal gradient and thermal conductivity of rocks or sediments...the formation temperature and thermal conductivity. Ideally, to...measurements require extra battery power supply and an additional...cooling curve for deducing the thermal properties has been contemplated......

Tien-Chang Lee; A. D. Duchkov; S. G. Morozov

2003-02-01T23:59:59.000Z

9

Continuous Processing of High Thermal Conductivity Polyethylene...  

Broader source: Energy.gov (indexed) [DOE]

Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Massachusetts Institute of...

10

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

Open Energy Info (EERE)

Thermal Gradient Holes At Coso Geothermal Area (1976) Thermal Gradient Holes At Coso Geothermal Area (1976) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Coso Geothermal Area (1976) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 1976 Usefulness useful DOE-funding Unknown Notes Temperatures have been obtained to depths up to 133 m in 22 boreholes with measurements being made at least four times in each borehole. Geothermal gradients ranged from 240C/km to 450 0C/km. References Combs, J. (1 December 1976) Heat flow determinations and implied thermal regime of the Coso geothermal area, California Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Coso_Geothermal_Area_(1976)&oldid=511217"

11

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

Open Energy Info (EERE)

Coso Geothermal Area (1974) Coso Geothermal Area (1974) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Thermal Gradient Holes 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 Notes Located 10 sites for heat flow boreholes using available seismic ground noise and electrical resistivity data; data collected from 9 of 10; thermal conductivity measurements were completed using both the needle probe technique and the divided bar apparatus with a cell arrangement. In the upper few hundred meters of the subsurface heat is being transferred by a conductive heat transfer mechanism with a value of ~ 15 µcal/cm2sec; the background heat flow is ~ 3.5 HFU.

12

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

Open Energy Info (EERE)

Date 1978 - 1985 Usefulness useful DOE-funding Unknown Exploration Basis Thermal gradient drilling also continued during this period, consisting of several holes including: The...

13

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

Open Energy Info (EERE)

EERE, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010) Exploration Activity...

14

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

Open Energy Info (EERE)

Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski, Et Al.,...

15

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

Open Energy Info (EERE)

Erkan, Et Al., 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al., 2007)...

16

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

Open Energy Info (EERE)

Obsidian Cliff Area (Hulen, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Obsidian Cliff Area (Hulen,...

17

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

Open Energy Info (EERE)

Area (Cumming And Mackie, 2007) Exploration Activity Details Location Glass Mountain Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not...

18

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network [OSTI]

semiconductors and ceramics with desired thermalthermal conductivity of several polycrystalline semiconductors and ceramics,Thermal Conductivity of Polycrystalline Semiconductors and Ceramics

Wang, Zhaojie

2012-01-01T23:59:59.000Z

19

NANO REVIEW Open Access Thermal conductivity and thermal boundary  

E-Print Network [OSTI]

NANO REVIEW Open Access Thermal conductivity and thermal boundary resistance of nanostructures and the thermal transport prop- erties is a key point to design materials with preferred thermal properties with the heat dissipation on them. The influence of the interfacial roughness on the thermal conductivity

Boyer, Edmond

20

Reduced Thermal Conductivity of Compacted Silicon Nanowires  

E-Print Network [OSTI]

Thermal-Barrier-Coating Applications,” Journa of American Ceramicthermal conductivity materials are typically found among ceramicsThermal Conductivity of Porous Materials: Application to Thick Barrier Coatings,” Journal of the European Ceramic

Yuen, Taylor S.

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Thermal Conductivity and Noise Attenuation in  

E-Print Network [OSTI]

.3.4 Corrosion-resistant and high-temperature filters 9 1.3.5 Acoustic Applications 9 2. THERMAL CONDUCTIVITY 2.1 THERMAL RESISTANCE 2.1.1 Thermal Conductors in Series 12 2.1.2 Thermal conductors in parallel 13 2 difference RTH Thermal resistance of conductor sb Stefan's constant T4 Temperature difference K* Total

Cambridge, University of

22

Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009)  

Open Energy Info (EERE)

Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Exploration Activity Details Location Salt Wells Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 2008 - 2008 Usefulness not indicated DOE-funding Unknown Exploration Basis Vulcan increased exploration efforts in the summer and fall of 2008, during which time the company drilled two temperature gradient holes (86-15 O on Pad 1 and 17-16 O on Pad 3); conducted seismic, gravity and magnetotelluric surveys; and drilled deep exploration wells at Pads 6 and 8 and binary wells at Pads 1, 2, 4, and 7. Notes

23

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett,  

Open Energy Info (EERE)

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

24

Experimental thermal conductivity and contact conductance of graphite composites  

E-Print Network [OSTI]

Graphite fiber organic matrix composites were reviewed ics. for potential heat sink applications in the electronics packaging determined the effective transverse and longitudinal thermal industry. This experimental investigation conductivity...

Jackson, Marian Christine

2012-06-07T23:59:59.000Z

25

Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et Al., 2004) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Lightning Dock Area Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Lightning Dock Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The awardee conducted seismic, gravity, resistivity, and airborne magnetic surveys, drilled temperature-gradient wells, and selected a location for a test well (52-7). The test well was drilled to a total depth of 770 m during 2003. Maximum temperatures approached 140degrees C and a short flow test suggested that a production well could be drilled to 600 m and produce economic volumes of 130-140degrees C fluid. A final assessment of the resource is currently being performed. References N. R. Warpinski, A. R. Sattler, R. Fortuna, D. A. Sanchez, J.

26

Electrical and thermal conductivities in dense plasmas  

SciTech Connect (OSTI)

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.

Faussurier, G., E-mail: gerald.faussurier@cea.fr; Blancard, C.; Combis, P.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

2014-09-15T23:59:59.000Z

27

Thermal Conductivity in Nanocrystalline Ceria Thin Films  

SciTech Connect (OSTI)

The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser-based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries.

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

2014-02-01T23:59:59.000Z

28

Thermal Conductance of Thin Silicon Nanowires  

Science Journals Connector (OSTI)

The thermal conductance of individual single crystalline silicon nanowires with diameters less than 30 nm has been measured from 20 to 100 K. The observed thermal conductance shows unusual linear temperature dependence at low temperatures, as opposed to the T3 dependence predicted by the conventional phonon transport model. In contrast to previous models, the present study suggests that phonon-boundary scattering is highly frequency dependent, and ranges from nearly ballistic to completely diffusive, which can explain the unexpected linear temperature dependence.

Renkun Chen, Allon I. Hochbaum, Padraig Murphy, Joel Moore, Peidong Yang, and Arun Majumdar

2008-09-02T23:59:59.000Z

29

Pumpernickel Valley Geothermal Project Thermal Gradient Wells | Open Energy  

Open Energy Info (EERE)

Valley Geothermal Project Thermal Gradient Wells Valley Geothermal Project Thermal Gradient Wells Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Pumpernickel Valley Geothermal Project Thermal Gradient Wells Details Activities (4) Areas (1) Regions (0) Abstract: The Pumpernickel Valley geothermal project area is located near the eastern edge of the Sonoma Range and is positioned within the structurally complex Winnemucca fold and thrust belt of north-central Nevada. A series of approximately north-northeast-striking faults related to the Basin and Range tectonics are superimposed on the earlier structures within the project area, and are responsible for the final overall geometry and distribution of the pre-existing structural features on the property. Two of these faults, the Pumpernickel Valley fault and Edna Mountain fault,

30

Some Remarks on Lattice Thermal Conductivity  

Science Journals Connector (OSTI)

The problem of lattice thermal conductivity (in an insulator) has been outstanding for many years. Debye and Peierls made fundamental contributions in relating finite thermal conductivity to anharmonic interactions between the normal modes of lattice vibration; detailed analysis and calculation however remains today a difficult problem. This paper presents a rather crude and elementary discussion of the problem for “classical” temperatures (T??) which yields a semiquantitative result in agreement with other workers. We are also able to make a rather direct estimate of the probable magnitude of the contribution to the thermal resistivity which arises from the quartic term in the lattice potential.

D. K. C. MacDonald

1960-01-01T23:59:59.000Z

31

Thermal conductance of metal-metal interfaces  

Science Journals Connector (OSTI)

The thermal conductance of interfaces between Al and Cu is measured in the temperature range 78thermal conductance of the as-deposited Al-Cu interface is 4GWm?2K?1 at room temperature, an order-of-magnitude larger than the phonon-mediated thermal conductance of typical metal-dielectric interfaces. The magnitude and the linear temperature dependence of the conductance are described well by a diffuse-mismatch model for electron transport at interfaces.

Bryan C. Gundrum; David G. Cahill; Robert S. Averback

2005-12-30T23:59:59.000Z

32

Molecular Dynamic Study of Thermal Conductivity of Amorphous Nanoporous Silica  

E-Print Network [OSTI]

as a thermal isolation layer”. Ceramics International, 34(Thermal conductivity of highly porous zirconia”. Journal of the European Ceramic

Coquil, Thomas; Fang, Jin; Pilon, Laurent

2011-01-01T23:59:59.000Z

33

Continuous Processing of High Thermal Conductivity Fibers and...  

Broader source: Energy.gov (indexed) [DOE]

We are developing a continuous fabrication process for high thermal conductivity polyethylene (PE) films While high thermal conductivity in (PE) has been shown in isolated...

34

Note: Local thermal conductivities from boundary driven non-equilibrium molecular dynamics simulations  

SciTech Connect (OSTI)

We report non-equilibrium molecular dynamics simulations of heat transport in models of molecular fluids. We show that the “local” thermal conductivities obtained from non-equilibrium molecular dynamics simulations agree within numerical accuracy with equilibrium Green-Kubo computations. Our results support the local equilibrium hypothesis for transport properties. We show how to use the local dependence of the thermal gradients to quantify the thermal conductivity of molecular fluids for a wide range of thermodynamic states using a single simulation.

Bresme, F., E-mail: f.bresme@imperial.ac.uk [Department of Chemistry, Chemical Physics Section, Imperial College London, London SW7 2AZ (United Kingdom); Department of Chemistry, Norwegian University of Science and Technology, Trondheim (Norway); Armstrong, J., E-mail: j.armstrong@imperial.ac.uk [Department of Chemistry, Chemical Physics Section, Imperial College London, London SW7 2AZ (United Kingdom)

2014-01-07T23:59:59.000Z

35

Thermal conductivity of low density carbon aerogels  

Science Journals Connector (OSTI)

Carbon aerogels with densities ranging from 0.182 to 0.052 g/cm3, pore sizes ranging from 88 to 227 nm, and particle diameters ranging from 20 to 13 nm were prepared. Thermal conductivity measurements by laser fl...

Junzong Feng; Jian Feng; Changrui Zhang

2012-10-01T23:59:59.000Z

36

Measurement of thermal conductivity P t BPart B  

E-Print Network [OSTI]

wave Take the Fourier transform of this frequency domain solution #12;For a low thermal conductivity thin filmFor a low thermal conductivity thin film on a high thermal conductivity substrate (Factor of 2Measurement of thermal conductivity Part A: P t BPart B: · Time domain thermoreflectance #12

Braun, Paul

37

Enhancing Thermal Conductivity and Reducing Friction  

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

Laboratory currently has several projects underway to develop advanced fluids, films, coatings, and Laboratory currently has several projects underway to develop advanced fluids, films, coatings, and processes to improve thermal conductivity and reduce friction. These measures are helping to increase energy efficiency for next-generation transportation applications. Superhard and Slick Coating (SSC) Opportunity: Friction, wear, and lubrication strongly affect the energy efficiency, durability, and environmental compatibility of

38

The thermal conductivity of rock under hydrothermal conditions: measurements and applications  

SciTech Connect (OSTI)

The thermal conductivities of most major rock-forming minerals vary with both temperature and confining pressure, leading to substantial changes in the thermal properties of some rocks at the high temperatures characteristic of geothermal systems. In areas with large geothermal gradients, the successful use of near-surface heat flow measurements to predict temperatures at depth depends upon accurate corrections for varying thermal conductivity. Previous measurements of the thermal conductivity of dry rock samples as a function of temperature were inadequate for porous rocks and susceptible to thermal cracking effects in nonporous rocks. We have developed an instrument for measuring the thermal conductivity of water-saturated rocks at temperatures from 20 to 350 °C and confining pressures up to 100 MPa. A transient line-source of heat is applied through a needle probe centered within the rock sample, which in turn is enclosed within a heated pressure vessel with independent controls on pore and confining pressure. Application of this technique to samples of Franciscan graywacke from The Geysers reveals a significant change in thermal conductivity with temperature. At reservoir-equivalent temperatures of 250 °C, the conductivity of the graywacke decreases by approximately 25% relative to the room temperature value. Where heat flow is constant with depth within the caprock overlying the reservoir, this reduction in conductivity with temperature leads to a corresponding increase in the geothermal gradient. Consequently, reservoir temperature are encountered at depths significantly shallower than those predicted by assuming a constant temperature gradient with depth. We have derived general equations for estimating the thermal conductivity of most metamorphic and igneous rocks and some sedimentary rocks at elevated temperature from knowledge of the room temperature thermal conductivity. Application of these equations to geothermal exploration should improve estimates of subsurface temperatures derived from heat flow measurements.

Williams, Colin F.; Sass, John H.

1996-01-24T23:59:59.000Z

39

Ultralow thermal conductivity and the thermal d t f i t fconductance of interfaces  

E-Print Network [OSTI]

are critical at the nanoscale · Low thermal conductivity in nanostructured materials ­ improved thermoelectric to the thermal conductivity of materials. · Ultralow thermal conductivity: beating the amorphous limitUltralow thermal conductivity and the thermal d t f i t fconductance of interfaces David G. Cahill

Braun, Paul

40

Regulation of thermal conductivity in hot galaxy clusters by MHD turbulence  

E-Print Network [OSTI]

The role of thermal conduction in regulating the thermal behavior of cooling flows in galaxy clusters is reexamined. Recent investigations have shown that the anisotropic Coulomb heat flux caused by a magnetic field in a dilute plasma drives a dynamical instability. A long standing problem of cooling flow theory has been to understand how thermal conduction can offset radiative core losses without completely preventing them. In this Letter we propose that magnetohydrodynamic turbulence driven by the heat flux instability regulates field-line insulation and drives a reverse convective thermal flux, both of which may mediate the stabilization of the cooling cores of hot clusters. This model suggests that turbulent mixing should accompany strong thermal gradients in cooling flows. This prediction seems to be supported by the spatial distribution of metals in the central galaxies of clusters, which shows a much stronger correlation with the ambient hot gas temperature gradient than with the parent stellar population.

Steven A. Balbus; Christopher S. Reynolds

2008-06-05T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Regulation of thermal conductivity in hot galaxy clusters by MHD turbulence  

E-Print Network [OSTI]

The role of thermal conduction in regulating the thermal behavior of cooling flows in galaxy clusters is reexamined. Recent investigations have shown that the anisotropic Coulomb heat flux caused by a magnetic field in a dilute plasma drives a dynamical instability. A long standing problem of cooling flow theory has been to understand how thermal conduction can offset radiative core losses without completely preventing them. In this Letter we propose that magnetohydrodynamic turbulence driven by the heat flux instability regulates field-line insulation and drives a reverse convective thermal flux, both of which may mediate the stabilization of the cooling cores of hot clusters. This model suggests that turbulent mixing should accompany strong thermal gradients in cooling flows. This prediction seems to be supported by the spatial distribution of metals in the central galaxies of clusters, which shows a much stronger correlation with the ambient hot gas temperature gradient than with the parent stellar populat...

Balbus, Steven A

2008-01-01T23:59:59.000Z

42

Strain-controlled thermal conductivity in ferroic twinned films  

E-Print Network [OSTI]

Large reversible changes of thermal conductivity are induced by mechanical stress, and the corresponding device is a key element for phononics applications. We show that the thermal conductivity ? of ferroic twinned thin ...

Li, Suzhi

43

Ultralow Thermal Conductivity of Isotope-Doped Silicon Nanowires  

E-Print Network [OSTI]

conductivity of SiNWs is about 2 orders of magnitude smaller than that of bulk crystals.18,19 The low thermal conductivity (0.05 W/m K) found in layered materials.22 So it is indispensable to reduce the thermal conUltralow Thermal Conductivity of Isotope-Doped Silicon Nanowires Nuo Yang, Gang Zhang,*, and Baowen

Li, Baowen

44

Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes  

E-Print Network [OSTI]

candidates for thermoelectric materials as they can provide extremely low thermal conductivity , relatively of boundary scattering on the thermal conductivity. We show that the material porosity strongly affects1 Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes Stefanie Wolf1

45

Pushing the boundaries of the thermal conductivity of materials  

E-Print Network [OSTI]

Pushing the boundaries of the thermal conductivity of materials David G. Cahill, C. Chiritescu, Y. · Advances in time-domain thermoreflectance. · Amorphous limit to the thermal conductivity of materials. #12;50 nm Interfaces are critical at the nanoscale · Low thermal conductivity in nanostructured

Braun, Paul

46

Thermal Conductivity of High-Modulus Polymer Fibers Xiaojia Wang,*,  

E-Print Network [OSTI]

to be the dominate carriers of heat. 1. INTRODUCTION Polymeric materials typically have a low thermal conductivity transfer is critical are often limited by low thermal conductivity. Here, we leverage the enormous research and low-density PE with varying fiber volume fractions.11 They reported an axial thermal conductivity

Cahill, David G.

47

Heat conductance in nonlinear lattices at small temperature gradients  

E-Print Network [OSTI]

This paper proposes a new methodological framework within which the heat conductance in 1D lattices can be studied. The total process of heat conductance is separated into two parts where the first one is the equilibrium process at equal temperatures $T$ of both ends and the second one -- non-equilibrium with the temperature $\\Delta T$ of one end and zero temperature of the other. This approach allows significant decrease of computational time at $\\Delta T \\to 0$. The threshold temperature $T_{\\rm thr}$ is found which scales $T_{\\rm thr}(N) \\sim N^{-3}$ with the lattice size $N$ and by convention separates two mechanisms of heat conductance: phonon mechanism dominates at $T T_{\\rm thr}$. Solitons and breathers are directly visualized in numerical experiments. The problem of heat conductance in non-linear lattices in the limit $\\Delta T \\to 0$ can be reduced to the heat conductance of harmonic lattice with time-dependent stochastic rigidities determined by the equilibrium process at temperature $T$. The detailed analysis is done for the $\\beta$-FPU lattice though main results are valid for one-dimensional lattices with arbitrary potentials.

T. Yu. Astakhova; V. N. Likhachev; G. A. Vinogradov

2010-06-09T23:59:59.000Z

48

Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Exploration Activity Details Location Socorro Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes Pre-existing evidence includes heat gradients of upwards of 490mW/m2 from thermal-gradient wells, tepid spring waters (32oC) and silica geochemistry indicating thermal 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 Gred Iii Project Retrieved from

49

Thermal Gradient Holes At Hualalai Northwest Rift Area (Thomas, 1986) |  

Open Energy Info (EERE)

Hualalai Northwest Rift Hualalai Northwest Rift Area (Thomas, 1986) Exploration Activity Details Location Hualalai Northwest Rift Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes Although not part of the current effort, two deep (approximately 2000 m) exploratory wells were drilled on the north flank of Hualalai near Puu Waawaa cinder cone. The geophysical data used for siting these wells were proprietary and hence unavailable for publication; however, the temperatures measured at the bottoms of the wells were reported to be below 20degrees C. Chemical analysis of 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) Geothermal Resources Assessment In

50

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

Open Energy Info (EERE)

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

51

SHOCKS AND THERMAL CONDUCTION FRONTS IN RETRACTING RECONNECTED FLUX TUBES  

SciTech Connect (OSTI)

We present a model for plasma heating produced by time-dependent, spatially localized reconnection within a flare current sheet separating skewed magnetic fields. The reconnection creates flux tubes of new connectivity which subsequently retract at Alfvenic speeds from the reconnection site. Heating occurs in gas-dynamic shocks (GDSs) which develop inside these tubes. Here we present generalized thin flux tube equations for the dynamics of reconnected flux tubes, including pressure-driven parallel dynamics as well as temperature-dependent, anisotropic viscosity and thermal conductivity. The evolution of tubes embedded in a uniform, skewed magnetic field, following reconnection in a patch, is studied through numerical solutions of these equations, for solar coronal conditions. Even though viscosity and thermal conductivity are negligible in the quiet solar corona, the strong GDSs generated by compressing plasma inside reconnected flux tubes generate large velocity and temperature gradients along the tube, rendering the diffusive processes dominant. They determine the thickness of the shock that evolves up to a steady state value, although this condition may not be reached in the short times involved in a flare. For realistic solar coronal parameters, this steady state shock thickness might be as long as the entire flux tube. For strong shocks at low Prandtl numbers, typical of the solar corona, the GDS consists of an isothermal sub-shock where all the compression and cooling occur, preceded by a thermal front where the temperature increases and most of the heating occurs. We estimate the length of each of these sub-regions and the speed of their propagation.

Guidoni, S. E.; Longcope, D. W., E-mail: guidoni@physics.montana.ed [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States)

2010-08-01T23:59:59.000Z

52

Morphology and thermal conductivity of yttria-stabilized zirconia coatings  

E-Print Network [OSTI]

yttria-stabilized zir- conia (YSZ) is then applied to provide thermal insulation [1]. This ceramic layer]. The thermal conductivity of the ceramic layer has been found to depend on the pore morphology within a coatingMorphology and thermal conductivity of yttria-stabilized zirconia coatings Hengbei Zhao a

Wadley, Haydn

53

Final Report: Thermal Conductance of Solid-Liquid Interfaces  

SciTech Connect (OSTI)

Research supported by this grant has significantly advanced fundamental understanding of the thermal conductance of solid-liquid interfaces, and the thermal conductivity of nanofluids and nanoscale composite materials. • The thermal conductance of interfaces between carbon nanotubes and a surrounding matrix of organic molecules is exceptionally small and this small value of the interface conductance limits the enhancement in thermal conductivity that can be achieved by loading a fluid or a polymer with nanotubes. • The thermal conductance of interfaces between metal nanoparticles coated with hydrophilic surfactants and water is relatively high and surprisingly independent of the details of the chemical structure of the surfactant. • We extended our experimental methods to enable studies of planar interfaces between surfactant-coated metals and water where the chemical functionalization can be varied between strongly hydrophobic and strongly hydrophilic. The thermal conductance of hydrophobic interfaces establishes an upper-limit of 0.25 nm on the thickness of the vapor-layer that is often proposed to exist at hydrophobic interfaces. • Our high-precision measurements of fluid suspensions show that the thermal conductivity of fluids is not significantly enhanced by loading with a small volume fraction of spherical nanoparticles. These experimental results directly contradict some of the anomalous results in the recent literature and also rule-out proposed mechanisms for the enhanced thermal conductivity of nanofluids that are based on modification of the fluid thermal conductivity by the coupling of fluid motion and the Brownian motion of the nanoparticles.

Cahil, David, G.; Braun, Paul, V.

2006-05-31T23:59:59.000Z

54

Thermal conductivity of graphene nanoribbons in noble gaseous environments  

SciTech Connect (OSTI)

We investigate the thermal conductivity of suspended graphene nanoribbons in noble gaseous environments using molecular dynamics simulations. It is reported that the thermal conductivity of perfect graphene nanoribbons decreases with the gaseous pressure. The decreasing is more obvious for the noble gas with large atomic number. However, the gaseous pressure cannot change the thermal conductivity of defective graphene nanoribbons apparently. The phonon spectra of graphene nanoribbons are also provided to give corresponding supports.

Zhong, Wei-Rong, E-mail: wrzhong@hotmail.com; Xu, Zhi-Cheng; Zheng, Dong-Qin [Department of Physics and Siyuan Laboratory, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Ai, Bao-Quan, E-mail: aibq@scnu.edu.cn [Laboratory of Quantum Information Technology, ICMP and SPTE, South China Normal University, Guangzhou 510006 (China)

2014-02-24T23:59:59.000Z

55

Estimation of composite thermal conductivity of a heterogeneous methane hydrate sample using iTOUGH2  

E-Print Network [OSTI]

15–17, 2006 ESTIMATION OF COMPOSITE THERMAL CONDUCTIVITY OFABSTRACT We determined the composite thermal conductivity (kfrom granular ice. The composite thermal conductivity was

Gupta, Arvind; Kneafsey, Timothy J.; Moridis, George J.; Seol, Yongkoo; Kowalsky, Michael B.; Sloan Jr., E.D.

2006-01-01T23:59:59.000Z

56

Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Exploration Activity Details Location Hot Springs Ranch Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes In 2005, Nevada Geothermal Power Company drilled four geothermal gradient wells, PVTG-1, -2, -3, and -4, and all four encountered geothermal fluids. The holes provided valuable water geochemistry, supporting the geothermometry results obtained from the hot springs and Magma well. The temperature data gathered from all the wells clearly indicates the presence of a major plume of thermal water centered on the Pumpernickel Valley

57

Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets  

Broader source: Energy.gov [DOE]

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.

58

Glass-like thermal conductivity in high efficiency thermoelectric materials  

Broader source: Energy.gov [DOE]

Discusses strategies to design thermoelectric materials with extremely low lattice thermal conductivity through modifications of the phonon band structure and phonon relaxation time.

59

Los Alamos probes mysteries of uranium dioxide's thermal conductivity  

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

of nuclear materials into the hands of terrorists and other non-state actors. The depleted uranium dioxide crystals used for the thermal conductivity measurements were...

60

Thermal Gradient Holes At Lightning Dock Area (Cunniff & Bowers, 2005) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Lightning Dock Area Thermal Gradient Holes At Lightning Dock Area (Cunniff & Bowers, 2005) Exploration Activity Details Location Lightning Dock Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The two gradient holes were sited on federal geothermal leases owned by Lightning Dock Geothermal, Inc. and both were drilled into lakebed sediments some distance from the intense shallow geothermal anomaly located in the eastern half of Section 7, Township 25 South, Range 19 West. References Roy A. Cunniff, Roger L. Bowers (2005) Final Technical Report, Geothermal Resource Evaluation And Definitioni (Gred) Program-Phases I, Ii, And Iii For The Animas Valley, Nm Geothermal Resource Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Lightning_Dock_Area_(Cunniff_%26_Bowers,_2005)&oldid=387460"

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Thermal Gradient Holes At Blue Mountain Area (Fairbank & Neggemann, 2004) |  

Open Energy Info (EERE)

Blue Mountain Area (Fairbank & Neggemann, 2004) Blue Mountain Area (Fairbank & Neggemann, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Blue Mountain Area (Fairbank & Neggemann, 2004) Exploration Activity Details Location Blue Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown References Brian D. Fairbank, Kim V. Niggemann (2004) Deep Blue No 1- A Slimhole Geothermal Discovery At Blue Mountain, Humboldt County, Nevada Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Blue_Mountain_Area_(Fairbank_%26_Neggemann,_2004)&oldid=386709" Category: Exploration Activities What links here Related changes Special pages Printable version Permanent link

62

Large Deviations in Stochastic Heat-Conduction Processes Provide a Gradient-Flow Structure for Heat Conduction  

E-Print Network [OSTI]

We consider three one-dimensional continuous-time Markov processes on a lattice, each of which models the conduction of heat: the family of Brownian Energy Processes with parameter $m$, a Generalized Brownian Energy Process, and the Kipnis-Marchioro-Presutti process. The hydrodynamic limit of each of these three processes is a parabolic equation, the linear heat equation in the case of the BEP$(m)$ and the KMP, and a nonlinear heat equation for the GBEP($a$). We prove the hydrodynamic limit rigorously for the BEP$(m)$, and give a formal derivation for the GBEP($a$). We then formally derive the pathwise large-deviation rate functional for the empirical measure of the three processes. These rate functionals imply gradient-flow structures for the limiting linear and nonlinear heat equations. We contrast these gradient-flow structures with those for processes describing the diffusion of mass, most importantly the class of Wasserstein gradient-flow systems. The linear and nonlinear heat-equation gradient-flow structures are each driven by entropy terms of the form $-\\log \\rho$; they involve dissipation or mobility terms of order $\\rho^2$ for the linear heat equation, and a nonlinear function of $\\rho$ for the nonlinear heat equation.

Mark A. Peletier; Frank Redig; Kiamars Vafayi

2014-03-19T23:59:59.000Z

63

Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Exploration Activity Details Location Kilauea East Rift Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes Two separate phases of geothermal exploratory drilling have occurred on the lower East Rift. The first was essentially a wildcat venture with relatively little surface exploratory data having been gathered, whereas the second was initiated after somewhat more geoscience information had been acquired under the Hawaii Geothermal Project. The results of the successful exploratory drilling program on the Kilauea

64

Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Exploration Activity Details Location Kilauea Summit Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes A deep borehole was drilled at the summit of Kilauea volcano, Hawaii, between April 6 and July 9, 1973. The hole is located approximately 1 km south of the edge of Halemaumau crater (Figs. 1 and 2), a crater within the summit caldera of the volcano. The total depth of the hole is 1262 m (4141 ft) measured from the derrick floor at an altitude of 1102 m (3616 ft). A description of the drilling program and some of the results obtained have

65

Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) | Open Energy  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) Exploration Activity Details Location Crump's Hot Springs Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes 8 wells References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Crump%27s_Hot_Springs_Area_(DOE_GTP)&oldid=402699"

66

Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Twenty-Nine Palms Geothermal Area (Sabin, Et Al., 2010) Exploration Activity Details Location Twenty-Nine Palms Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes The first and only Seabee drilling project was the installation of five TGHs at the Camp Wilson region of the MCAGCC Marine base near Twenty-Nine Palms, CA. While the program was a success and GPO identified an anomaly where a deep, slim hole is to be drilled in June, 2010, the Seabee rig was sent oversees soon after drilling was completed. If/when another rig

67

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

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At 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) Exploration Activity Details Location Fish Lake Valley Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes 2 wells References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Fish_Lake_Valley_Area_(DOE_GTP)&oldid=511222" Categories:

68

Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

69

Integrated thermal-microstructure model to predict the property gradients in resistance spot steel welds  

SciTech Connect (OSTI)

An integrated model approach was proposed for relating resistance welding parameters to weldment properties. An existing microstructure model was used to determine the microstructural and property gradients in resistance spot welds of plain carbon steel. The effect of these gradients on the weld integrity was evaluated with finite element analysis. Further modifications to this integrated thermal-microstructure model are discussed.

Babu, S.S.; Riemer, B.W.; Santella, M.L. [Oak Ridge National Lab., TN (United States); Feng, Z. [Edison Welding Inst., Columbus, OH (United States)

1998-11-01T23:59:59.000Z

70

Fiber/Matrix Interfacial Thermal Conductance Effect on the Thermal Conductivity of SiC/SiC Composites  

SciTech Connect (OSTI)

SiC/SiC composites used in fusion reactor applications are subjected to high heat fluxes and require knowledge and tailoring of their in-service thermal conductivity. Accurately predicting the thermal conductivity of SiC/SiC composites as a function of temperature will guide the design of these materials for their intended use, which will eventually include the effects of 14-MeV neutron irradiations. This paper applies an Eshelby-Mori-Tanaka approach (EMTA) to compute the thermal conductivity of unirradiated SiC/SiC composites. The homogenization procedure includes three steps. In the first step EMTA computes the homogenized thermal conductivity of the unidirectional (UD) SiC fiber embraced by its coating layer. The second step computes the thermal conductivity of the UD composite formed by the equivalent SiC fibers embedded in a SiC matrix, and finally the thermal conductivity of the as-formed SiC/SiC composite is obtained by averaging the solution for the UD composite over all possible fiber orientations using the second-order fiber orientation tensor. The EMTA predictions for the transverse thermal conductivity of several types of SiC/SiC composites with different fiber types and interfaces are compared to the predicted and experimental results by Youngblood et al.

Nguyen, Ba Nghiep; Henager, Charles H.

2013-04-20T23:59:59.000Z

71

Nanoscale thermal transport and the thermal conductance of interfaces  

E-Print Network [OSTI]

-8 2008 #12;Er-fiber laser system, UIUC Nov. 2007 #12;Solid-liquid interfaces: Two approaches · Transient-wide: ­ thermal interface materials ­ so-called "nanofluids" (suspensions in liquids) ­ polymer composites absorption depends on temperature of the nanotube · Assume heat capacity is comparable to graphite · Cooling

Braun, Paul

72

Resonant bonding leads to low lattice thermal conductivity  

E-Print Network [OSTI]

Understanding the lattice dynamics and low thermal conductivities of IV–VI, V[subscript 2]–VI[subscript 3] and V materials is critical to the development of better thermoelectric and phase-change materials. Here we provide ...

Lee, Sangyeop

73

Investigation on thermal conductivity and AC impedance of graphite suspension  

E-Print Network [OSTI]

Over the past decade, some groups have reported that nanofluids, which are liquids containing suspensions of nanoparticles, have substantially higher thermal conductivity than that of the base fluids. However, the reported ...

Wang, Jianjian, S.M. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

74

Reduction of Thermal Conductivity in Wafer-Bonded Silicon  

SciTech Connect (OSTI)

Blocks of silicon up to 3-mm thick have been formed by directly bonding stacks of thin wafer chips. These stacks showed significant reductions in the thermal conductivity in the bonding direction. In each sample, the wafer chips were obtained by polishing a commercial wafer to as thin as 36 {micro}m, followed by dicing. Stacks whose starting wafers were patterned with shallow dots showed greater reductions in thermal conductivity. Diluted-HF treatment of wafer chips prior to bonding led to the largest reduction of the effective thermal conductivity, by approximately a factor of 50. Theoretical modeling based on restricted conduction through the contacting dots and some conduction across the planar nanometer air gaps yielded fair agreement for samples fabricated without the HF treatment.

ZL Liau; LR Danielson; PM Fourspring; L Hu; G Chen; GW Turner

2006-11-27T23:59:59.000Z

75

Thermal Gradient Holes At Chocolate Mountains Area (Alm, Et Al., 2010) |  

Open Energy Info (EERE)

Chocolate Mountains Area (Alm, Et Al., 2010) Chocolate Mountains Area (Alm, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chocolate Mountains Area (Alm, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique 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 gradient holes were completed to a depth of 500' below ground surface. Sites were selected based on the compilation of previous exploration and resulting data is being integrated into the most recent geologic model. This model will form the basis for the selection of a deeper (2000'-4000') temperature gradient drilling campaign at the CMAGR in

76

Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) | Open  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) Exploration Activity Details Location Hawthorne Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding 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 shallow resource, the Navy will drill one or two

77

Thermal Gradient Holes At Twenty-Nine Palms Area (Page, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Twenty-Nine Palms Thermal Gradient Holes At Twenty-Nine Palms Geothermal Area (Page, Et Al., 2010) Exploration Activity Details Location Twenty-Nine Palms Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes From November 2008 to March 2009, Seabees from the Naval Construction Division (NCD) successfully completed fivetemperature 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 typically encountered. Each hole varied slightly in depth, ranging from 600ft to 1,000ft; however, each hole has been completed to acceptable standards of the GPO. Upon completion of drilling, 3" metal tubing was inserted to

78

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...

79

Process for fabricating composite material having high thermal conductivity  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

80

Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit & Blackwell,  

Open Energy Info (EERE)

Hot Creek Ranch Area (Benoit & Blackwell, Hot Creek Ranch Area (Benoit & Blackwell, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) Exploration Activity Details Location Upper Hot Creek Ranch Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes Ten temperature gradient holes up to 500' deep were initially planned but higher than anticipated drilling and permitting costs within a fixed budget reduced the number of holes to five. Four of the five holes drilled to depths of 300 to 400' encountered temperatures close to the expected regional thermal background conditions. These four holes failed to find any evidence of a large thermal anomaly surrounding the UHCR hot springs. The

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Thermal History of the Earth with consideration of the Variable Thermal Conductivity of its Mantle  

Science Journals Connector (OSTI)

......the data about electric conductivity...give no thermal resistance and the integral...the number of elementary cells in I cm3...of heat in an elementary volume v k cm3...inverse to the resistances:the thermal...the hydraulic resistance determining...charge,h-electric conductivity......

H. A. Lubimova

1958-06-01T23:59:59.000Z

82

Thermal rectification and negative differential thermal resistance in lattices with mass gradient Nuo Yang,1 Nianbei Li,1 Lei Wang,1 and Baowen Li1,2,  

E-Print Network [OSTI]

Thermal rectification and negative differential thermal resistance in lattices with mass gradient thermal resistance is observed. Possible applications in constructing thermal rectifiers and thermal properties, the thermal properties of graded materials have not yet been fully studied see the recent review

Li, Baowen

83

Thermal Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) |  

Open Energy Info (EERE)

Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

84

Thermal conductivity of rigid foam insulations for aerospace vehicles  

Science Journals Connector (OSTI)

The present work describes measurements of the effective thermal conductivity of NCFI 24-124 foam, a spray-on foam insulation used formerly on the Space Shuttle external fuel tank. A novel apparatus to measure the effective thermal conductivity of rigid foam at temperatures ranging from 20 K to 300 K was developed and used to study three samples of NCFI 24-124 foam insulation. In preparation for measurement, the foam samples were either treated with a uniquely designed moisture absorption apparatus or different residual gases to study their impact on the effective thermal conductivity of the foam. The resulting data are compared to other measurements and mathematical models reported in the literature.

M. Barrios; S.W. Van Sciver

2013-01-01T23:59:59.000Z

85

Thermally conductive cementitious grout for geothermal heat pump systems  

DOE Patents [OSTI]

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.

Allan, Marita (Old Field, NY)

2001-01-01T23:59:59.000Z

86

Thermal conductivity of highly-ordered mesoporous titania thin films from 30 to 320 K  

E-Print Network [OSTI]

Thermal resistance of grain boundaries in alumina ceramicsThermal conductivity of highly porous zirconia”. Journal of the European Ceramic

2011-01-01T23:59:59.000Z

87

Thermal Gradient Holes At Chocolate Mountains Area (Sabin, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Chocolate Mountains Area Thermal Gradient Holes At Chocolate Mountains Area (Sabin, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes In lieu of Seabee TGH drilling, GPO awarded a large IDIQ TGH drilling contract in December, 2009. Over the next two years, 90 500-ft TGHs 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 programs can be found in the Chocolate Mountains and Hawthorne papers also available in this volume. References Andrew Sabin, S. Bjornstad, M. Lazaro, D. Meade, C. Page, S. Alm, A. Tiedeman, W. C. Huang (2010) Navy's Geothermal Program Office: Overview

88

Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives  

SciTech Connect (OSTI)

The objective of this research is to increase the thermal conductivity of uranium oxide (UO{sub 2}) without significantly impacting its neutronic properties. The concept is to incorporate another high thermal conductivity material, silicon carbide (SiC), in the form of whiskers or from nanoparticles of SiC and a SiC polymeric precursor into UO{sub 2}. This is expected to form a percolation pathway lattice for conductive heat transfer out of the fuel pellet. The thermal conductivity of SiC would control the overall fuel pellet thermal conductivity. The challenge is to show the effectiveness of a low temperature sintering process, because of a UO{sub 2}-SiC reaction at 1,377°C, a temperature far below the normal sintering temperature. Researchers will study three strategies to overcome the processing difficulties associated with pore clogging and the chemical reaction of SiC and UO{sub 2} at temperatures above 1,300°C:

Ronald baney; James Tulenko

2012-11-20T23:59:59.000Z

89

Polymer Nanofibers with Outstanding Thermal Conductivity and Thermal Stability: Fundamental Linkage between Molecular Characteristics and Macroscopic Thermal Properties  

E-Print Network [OSTI]

Polymer nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of polymer nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of polymer nanofibers. Ten different polymer nanofibers with systematically chosen molecular structures are studied using large scale molecular dynamics simulations. We found that high thermal conductivity and good thermal stability can be achieved in polymers with rigid backbones, exemplified by {\\pi}-conjugated polymers, due to suppressed segmental rotations and large phonon group velocities. The low probability of segmental rotation does not only prevent temperature-induced phase transition but also enables long phonon mean free paths due to reduced di...

Zhang, Teng; Luo, Tengfei

2014-01-01T23:59:59.000Z

90

The Impact of Thermal Conductivity and Diffusion Rates on Water Vapor Transport through Gas Diffusion Layers  

E-Print Network [OSTI]

Water management in a hydrogen polymer electrolyte membrane (PEM) fuel cell is critical for performance. The impact of thermal conductivity and water vapor diffusion coefficients in a gas diffusion layer (GDL) has been studied by a mathematical model. The fraction of product water that is removed in the vapour phase through the GDL as a function of GDL properties and operating conditions has been calculated and discussed. Furthermore, the current model enables identification of conditions when condensation occurs in each GDL component and calculation of temperature gradient across the interface between different layers, providing insight into the overall mechanism of water transport in a given cell design. Water transport mode and condensation conditions in the GDL components depend on the combination of water vapor diffusion coefficients and thermal conductivities of the GDL components. Different types of GDL and water removal scenarios have been identified and related to experimentally-determined GDL proper...

Burlatsky, S F; Gummallaa, M; Condita, D; Liua, F

2013-01-01T23:59:59.000Z

91

Thermal Gradient Holes At Lake City Hot Springs Area (Warpinski, Et Al.,  

Open Energy Info (EERE)

2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Lake City Hot Springs Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Lake City Hot Springs Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The Lake City site, which is located in far northeastern California, 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 accurate siting or drilling of production wells. Some deep wells, several seismic lines, limited gravity surveys, and geochemical and geological studies have suggested that the geothermal

92

Thermal Conductivity of Composites Under Di erent Heating Scenarios  

E-Print Network [OSTI]

Thermal Conductivity of Composites Under Di#11;erent Heating Scenarios H.T. Banks #3; , J.H. Hogan of composites under three di#11;erent heating scenarios: (i) a laser pulse heat source, (ii) a preheated composite sample, and (iii) a continuous heat source. 1 Introduction Adhesives such as epoxies, gels

93

THERMAL CONDUCTIVITY OF POWDER INSULATIONS FOR CRYOGENIC STORAGE  

E-Print Network [OSTI]

THERMAL CONDUCTIVITY OF POWDER INSULATIONS FOR CRYOGENIC STORAGE VESSELS Y. S. Choi1 '3 , M. N), powder insulation, and foam insulation, are used in the cryogenic storage vessels. Among CP823, Advances in Cjyogenie Engineering: Transactions of the Cryogenic Engineering Conference - CEC, Vol. 51, edited by J. G

Chang, Ho-Myung

94

Remarkable Reduction of Thermal Conductivity in Silicon Nanotubes  

E-Print Network [OSTI]

localization, thermoelectric material T hermoelectric (TE) materials can provide electricity when subjected materials can be characterized by the dimen- sionless thermoelectric figure of merit ZT ) S2 T/, where S to be responsible for the reduction of thermal conductivity. Our study suggests SiNT is a promising thermoelectric

Li, Baowen

95

Mode dependent lattice thermal conductivity of single layer graphene  

SciTech Connect (OSTI)

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.

Wei, Zhiyong; Yang, Juekuan; Bi, Kedong; Chen, Yunfei, E-mail: yunfeichen@seu.edu.cn [Jiangsu Key Laboratory for Design and Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096 (China)

2014-10-21T23:59:59.000Z

96

Thin-film aerogel thermal conductivity measurements via 3?  

Science Journals Connector (OSTI)

The limiting constraint in a growing number of nano systems is the inability to thermally tune devices. Silica aerogel is widely accepted as the best solid thermal insulator in existence and offers a promising solution for microelectronic systems needing superior thermal isolation. In this study, thin-film silica aerogel films varying in thickness from 250 to 1280 nm were deposited on SiO2 substrates under a variety of deposition conditions. These samples were then thermally characterized using the 3? technique. Deposition processes for depositing the 3? testing mask to the sample were optimized and it was demonstrated that thin-film aerogel can maintain its structure in common fabrication processes for microelectromechanical systems. Results indicate that thin-film silica aerogel can maintain the unique, ultra-low thermal conductivity commonly observed in bulk aerogel, with a directly measured thermal conductivity as low as 0.024 W/m-K at temperature of 295 K and pressure between 0.1 and 1 Pa.

M.L. Bauer; C.M. Bauer; M.C. Fish; R.E. Matthews; G.T. Garner; A.W. Litchenberger; P.M. Norris

2011-01-01T23:59:59.000Z

97

Heat conduction through a trapped solid: effect of structural changes on thermal conductance  

E-Print Network [OSTI]

We study the conduction of heat across a narrow solid strip trapped by an external potential and in contact with its own liquid. Structural changes, consisting of addition and deletion of crystal layers in the trapped solid, are produced by altering the depth of the confining potential. Nonequilibrium molecular dynamics simulations and, wherever possible, simple analytical calculations are used to obtain the thermal resistance in the liquid, solid and interfacial regions (Kapitza or contact resistance). We show that these layering transitions are accompanied by sharp jumps in the contact thermal resistance. Dislocations, if present, are shown to increase the thermal resistance of the strip drastically.

Debasish Chaudhuri; Abhishek Chaudhuri; Surajit Sengupta

2006-11-14T23:59:59.000Z

98

The thermal conductivity of silicon nitride with molybdenum disilicide additions  

SciTech Connect (OSTI)

Room-temperature thermal conductivity has been measured for a series of silicon nitride (Si{sub 3}N{sub 4}) matrix composites with molybdenum disilicide (MoSi{sub 2}) additions of 2, 5 10, 25 and 50 wt. %. Included in these measurements were a pure MoSi{sub 2} sample and a Si{sub 3}N{sub 4} sample containing only sintering aids. Aluminum oxide (Al{sub 2}O{sub 3}) and yttrium oxide (Y{sub 2}O{sub 3}) were added as the sintering aids, at approximately 6 and 2 respectively. When the amount of MoSi{sub 2} was increased to greater than 10 wt. %, the amount of the sintering aids necessary to densify the composite was decreased. No sintering aids were added to the pure MoSi{sub 2} sample. Thermal conductivities of the Si{sub 3}N{sub 4} sample without MoSi{sub 2} and the pure MoSi{sub 2} sample wee 36 W/m.K and 52 W/m.K respectively, which agree very well with the literature values for similar materials. No statistically significant changes were observed in the thermal conductivity for those samples containing up to 10 wt. % MoSi{sub 2}. However, between 10 and 25 wt. % MoSi{sub 2} there was a dramatic decrease in the thermal conductivity from 37 to 20.9 W/m.K. The thermal conductivity then increased steadily with further additions of MoSi{sub 2} up to 52 W/m.K for the pure MoSi{sub 2} specimen.

Beecher, S.C.; Dinwiddie, R.B.; Abeel, A.M.; Lowden, R.A.

1993-12-31T23:59:59.000Z

99

Thermal conductivity of Permian Basin bedded salt at elevated pressure  

SciTech Connect (OSTI)

Measurements of thermal conductivity were made on five core samples of bedded rock salt from the Permian Basin in Texas. The sample size was 100 mm in diameter by 250 mm in length. Measurements were conducted under confining pressures ranging from 3.8 to 31.0 MPa and temperatures from room temperature to 473 K. Conductivity showed no dependence on confining pressure, but showed a monotonic, negative temperature dependence. Four of the five samples showed conductivities clustered in a range of 5.6 +- 0.5 W/m.K at room temperature, falling to 3.6 +- 0.3 W/m.K at 473 K. These values are approximately 20% below the values for pure halite, reflecting perhaps the 5 to 20% non-halite component of the samples. The fifth sample showed a conductivity vs temperature dependence much like that of halite. 19 references, 4 figures.

Durham, W.B.; Boro, C.O.; Beiriger, J.M.

1984-04-01T23:59:59.000Z

100

Effective thermal conduction model for estimating global warming  

Science Journals Connector (OSTI)

This paper presents a simple way to approximate the dependence of the global mean air temperature at Earth’s surface on the atmospheric concentration of carbon dioxide. It treats the atmosphere as a blanket the effective thermal conductivity of which is a decreasing function of the amount of CO 2 present and does not involve the details of energy transport. The only data required are the CO 2 concentrations at the middle of the nineteenth and the end of the twentieth centuries and the shift in temperature that has occurred over that time. This elementary phenomenological energy-balance approach is well suited for undergraduate physics courses to illustrate thermal conduction and radiation by way of the very interesting and critically important example of greenhouse warming of Earth.

Anthony B. Wolbarst

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

eXtremes of heat conduction: Pushing the boundaries of the thermal  

E-Print Network [OSTI]

eXtremes of heat conduction: Pushing the boundaries of the thermal conductivity of materials David. · For example, simplest case of thermal conductivity where resistive scattering dominates C() v() l() d C for the highest thermal conductivity any material (higher conductivity than diamond) Yu et al. (2005) Maruyama

Braun, Paul

102

On the heat flux vector for flowing granular materials--Part I: effective thermal conductivity and background  

SciTech Connect (OSTI)

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier’s law of heat conduction and for complex materials such as nonlinear fluids, porous media, or granular materials, the coeffcient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame-invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier’s law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non-linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or suffcient.

Massoudi, Mehrdad

2006-09-10T23:59:59.000Z

103

High-Throughput Computational Screening of thermal conductivity, Debye temperature and Gruneisen parameter  

E-Print Network [OSTI]

thermal properties such as the Debye temperature and the thermal conductivity of materials. We demonstrate studied for the past few decades6 . Low thermal conductivity mate- rials constitute the basis of a new and predict the thermal conductivity of differ- ent materials8,9,11­16 . Such evaluation of the higher

Curtarolo, Stefano

104

Thermal Gradient Holes At Hawthorne Area (Sabin, Et Al., 2010) | Open  

Open Energy Info (EERE)

Sabin, Et Al., 2010) Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hawthorne Area (Sabin, Et Al., 2010) Exploration Activity Details Location Hawthorne Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes In lieu of Seabee TGH drilling, GPO awarded a large IDIQ TGH drilling contract in December, 2009. Over the next two years, 90 500-ft TGHs 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 programs can be found in the Chocolate Mountains and Hawthorne papers also available in this volume. References Andrew Sabin, S. Bjornstad, M. Lazaro, D. Meade, C. Page, S. Alm, A.

105

Thermal Gradient Holes At Walker-Lane Transitional Zone Region (Pritchett,  

Open Energy Info (EERE)

Walker-Lane Transitional Zone Region (Pritchett, Walker-Lane Transitional Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Walker-Lane Transitional Zone Region (Pritchett, 2004) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

106

Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al., 2002) | Open  

Open Energy Info (EERE)

Et Al., 2002) Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove 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 location. Drilling of the test well was completed in the fall of 2001 and results are currently being evaluated. The total depth of the well is 598 m with a

107

Thermal Gradient Holes At Spencer Hot Springs Area (Shevenell, Et Al.,  

Open Energy Info (EERE)

Hot Springs Area (Shevenell, Et Al., Hot Springs Area (Shevenell, Et Al., 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Spencer Hot Springs Area (Shevenell, Et Al., 2008) Exploration Activity Details Location Spencer Hot Springs Area Exploration Technique Thermal Gradient 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 geothermal community. Exploration holes at Tungsten Mountain and McGuiness Hills (Spencer Hot Springs?) in 2004 and 2005 encountered hot water and steam at depths of meters with fluid geothermometry indicating reservoir temperatures of 170 to 200oC. More information can be obtained from the Nevada Bureau of Mines and Geology web

108

Thermal Gradient Holes At Fort Bidwell Area (Lafleur, Et Al., 2010) | Open  

Open Energy Info (EERE)

Bidwell Area (Lafleur, Et Al., 2010) Bidwell Area (Lafleur, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fort Bidwell Area (Lafleur, Et Al., 2010) Exploration Activity Details Location Fort Bidwell Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes "Four wells have been successfully drilled into this resource since the early 1980s using a combination of funds provided by the California Energy Commission (CEC) and the United State Department of Energy (USDOE). The first three wells, FB-1, -2 and -3 have been discussed in a previous paper (Barker et al., 2005). The current status of the FBIC project to evaluate the potential geothermal resource under the reservation is that a deep

109

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

E-Print Network [OSTI]

1 Pump-probe measurements of the thermal conductivity tensor for materials lacking in conductivity corresponding to the scanning direction. Also, we demonstrate Nb- V as a low thermal conductivity thermal conductivity tensor and the illuminating spots have arbitrary intensity profiles

Cahill, David G.

110

Submitted to Phys. Rev. B, June 2013 Ultralow thermal conductivity of fullerene derivatives  

E-Print Network [OSTI]

conductivity in WSe2. The objective our study is to verify the exceptionally low thermal conductivities of these materials might affect their thermal conductivities. In addition to PCBM, we also investigate [6,6]-phenyl on the appearance of ultralow thermal conductivity in this class of materials. We use time-domain thermoreflectance

Cahill, David G.

111

E-Print Network 3.0 - angle-resolved thermal conductivity Sample...  

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

single-walled carbon nanotube films Kei... , the expectation on single-walled carbon nanotubes (SWNTs) to possess high thermal conductivity has attracted... of the thermal...

112

The Thermal Conductivity of Low Density Concretes Containing Perlite  

E-Print Network [OSTI]

-Tov, "HEATING5 - An IBM 360 Heat Conduction Program," ORNL/CSD/tm-15(1977). Oak Ridge National Laboratory, Oak Ridge, TN 37831. [5J Expanded Shale Clay and Slate Institute, "Lightweight Concrete Information Sheet," No.4, Washington, D.C., 1958. [6J Moore..., J. P., R. S. Graves, J. G. Stradley, J. H. Hannah, and D. L. McElroy, "Some Thermal Transport Properties of a Limestone Concrete," ORNL/TM-2644 (August 1969), Oak Ridge National Laboratory, Oak Ridge, TN 37831. [7J Valore, R. C., Jr., "Cellular...

Yarbrough, D. W.

113

Effective thermal conductivity of packed beds of spheres  

E-Print Network [OSTI]

of N are known only for certain types of regular packing, however, an empirical relation for m ) 0. 3 is given as N = 11. 6(l ? m) (22) When a load is applied to a bed of spheres, the contact area between spheres is determined using the Hertz... the authors compared their analytical solutions to has consistently dealt with beds of materials which have a very low thermal conductivity compared to that of the brass and aluminum spheres. These materials have been solid and hollow glass spheres, ceramic...

Duncan, Allen Buchanan

1987-01-01T23:59:59.000Z

114

Experimental investigation of high temperature thermal contact resistance between high thermal conductivity C/C material and Inconel 600  

Science Journals Connector (OSTI)

Abstract Thermal contact resistance at the assembly interface plays an important role in high temperature structure design and safety assessment. Thermal contact resistance between high thermal conductivity C/C material and superalloy Inconel 600 was experimentally investigated in the present paper. They are widely used in thermal protection structures of heat-pipe-cooled leading edges to enhance interface heat transfer. Results showed that thermal contact resistance between the two materials is about 5 × 10?5 m2 K/W, and it is necessary to take into account the effect of the thermal contact resistance in high thermal conductivity C/C material related thermal structure design.

Donghuan Liu; Yan Luo; Xinchun Shang

2015-01-01T23:59:59.000Z

115

Experimental Investigation of Size Effects on the Thermal Conductivity of Silicon-Germanium Alloy Thin Films  

E-Print Network [OSTI]

We experimentally investigate the role of size effects and boundary scattering on the thermal conductivity of silicon-germanium alloys. The thermal conductivities of a series of epitaxially grown Si[subscript 1-x] Ge[subscript ...

Cheaito, Ramez

116

Thermal Conductivity of Certain Rock Types and its Relevance to the Storage of Nuclear Waste  

Science Journals Connector (OSTI)

Nine rocks selected from the surface of three plutons have been examined petrographically and their thermal conductivities measured in the temperature range of 100° to 500°C. The thermal conductivities of differe...

V. V. Mirkovich; J. A. Soles

1978-01-01T23:59:59.000Z

117

Ultralow Thermal Conductivity in Organoclay Nanolaminates Synthesized via Simple Self-Assembly  

E-Print Network [OSTI]

transform fully dense solids into ultralow thermal conductivity materials. Here we report a simple self of nanolaminate spacing. A simple series resistance model describes the behavior and gives an interfacial thermal thermal conductance For phonon-mediated heat conduction, a material is generally thought to reach its

Braun, Paul

118

Anomalous thermal conduction characteristics of phase change composites with single walled carbon nanotube inclusions  

E-Print Network [OSTI]

of the phase change materials, because low thermal conductivity hinders the rate of energy storage and release of the new way of improving the thermal conductivity of phase change materials by seeding nano materials way to manipulate the thermal conductivity of nano composites using one dimensional nano material

Maruyama, Shigeo

119

Origin of Low Thermal Conductivity in Nuclear Fuels Quan Yin and Sergey Y. Savrasov  

E-Print Network [OSTI]

, the thermal conductivity of UO2 is very low, and the search for alternative materials continuesOrigin of Low Thermal Conductivity in Nuclear Fuels Quan Yin and Sergey Y. Savrasov Department in a very low thermal conductivity of modern nuclear fuels. Consider semiconducting UO2 which is a main

Savrasov, Sergej Y.

120

Calculations of dynamical properties of skutterudites: Thermal conductivity, thermal expansivity, and atomic mean-square displacement  

SciTech Connect (OSTI)

While the thermal conductivity of the filled skutterudites has been of great interest it had not been calculated within a microscopic theory. Here a central force, Guggenheim-McGlashen, model with parameters largely extracted from first-principles calculations and from spectroscopic data, specific to LaFe{sub 4} Sb{sub 12} or CoSb{sub 3} , is employed in a Green-Kubo/molecular dynamics calculation of thermal conductivity as a function of temperature. We find that the thermal conductivity of a filled solid is more than a factor of two lower than that of an unfilled solid, assuming the “framework” interatomic force parameters are the same between filled and unfilled solids, and that this decrease is almost entirely due to the cubic anharmonic interaction between filling and framework atoms. In addition, partially as a test of our models, we calculate thermal expansivity and isotropic atomic mean-square displacements using both molecular dynamics and lattice dynamics methods. These quantities are in reasonable agreement with experiment, increasing our confidence in the anharmonic parameters of our models. We also find an anomalously large filling-atom mode Gruneisen parameter that is apparently observed for a filled skutterudite and is observed in a clathrate.

Bernstein, N.; Feldman, J. L.; Singh, David J.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

T I ENHANCING THERMAL CONDUCTIVITY OF FLUIDS WITH NANOPARTICLES*  

Office of Scientific and Technical Information (OSTI)

JAM 1 1 1935 JAM 1 1 1935 b T I ENHANCING THERMAL CONDUCTIVITY OF FLUIDS WITH NANOPARTICLES* Stephen U. S. Choi 1 and J. A. Eastman 2 1 Energy Technology Division and ^Materials Science Division Argonne National Laboratory, Argonne, IL 60439 October 1995 The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. W-31-109-ENG-38. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi-

122

MODEL FOR DETERMINING THE EFFECTIVE THERMAL CONDUCTIVITY OF PARTICLE BEDS WITH HIGH SOLID-TO-GAS THERMAL  

E-Print Network [OSTI]

MODEL FOR DETERMINING THE EFFECTIVE THERMAL CONDUCTIVITY OF PARTICLE BEDS WITH HIGH SOLID-TO-GAS- to-gas conductivity ratio (such as Be and He). The model has the capability of accounting with high solid-to-gas thermal conductivity ratios. This paper summarizes this modeling effort. Model

Abdou, Mohamed

123

Thermal gradient crystals as tuneable monochromator for high energy X-rays  

SciTech Connect (OSTI)

At the high energy synchrotron radiation beamline BW5 at DORIS III at DESY a new monochromator providing broad energy bandwidth and high reflectivity is in use. On a small 10x10x5 mm{sup 3} silicon crystal scattering at the (311) reflection a thermal gradient is applied, which tunes the scattered energy bandwidth. The (311) reflection strongly suppresses the higher harmonics allowing the use of an image plate detector for crystallography. The monochromator can be used at photon energies above 60 keV.

Ruett, U.; Schulte-Schrepping, H.; Heuer, J.; Zimmermann, M. von [Hamburger Synchrotron Strahlungslabor (HASYLAB), at Deutsches Elektronensychrotron (DESY), Notkestr. 85, 22603 Hamburg (Germany)

2010-06-23T23:59:59.000Z

124

Ballistic phonon thermal conductance in graphene nano-ribbon: First-principles calculations  

SciTech Connect (OSTI)

Ballistic phonon thermal conductances for graphene nanoribbons are investigated using first-principles calculations with the density functional perturbation theory and the Landauer theory. The phonon thermal conductance per unit width for GNR is larger than that for graphene and increases with decreasing ribbon width. The normalized thermal conductances with regard to a thermal quantum for GNRs are higher than those for the single-walled carbon nanotube that have circumferential lengths corresponding to the width of GNR.

Nakamura, Jun; Tomita, Hiroki [Department of Engineering Sciences, The University of Electro-Communications (UEC-Tokyo), 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan)

2013-12-04T23:59:59.000Z

125

Computational modeling of thermal conductivity of single walled carbon nanotube polymer composites  

E-Print Network [OSTI]

to solid materials like metals. Keywords: SWNT, Random Walk, Thermal Conductivity, Composites 1 at the interface between the matrix material and the SWNT plays a very important role on the effective thermal conductivity. This thermal resistance is known as the Kapitza resistance [8]. According to the acoustic theory

Maruyama, Shigeo

126

Thermal conductivity of nitrogenated ultrananocrystalline diamond films M. Shamsa,1,a  

E-Print Network [OSTI]

light on the nature of thermal conduction in partially disordered nanostructured materials and can be used for estimating the thermal resistance of doped UNCD films. © 2008 American Institute of Physics, chemical inertness, record high thermal conductivity, high mobility of charge carriers, and high electron

127

INFLUENCE OF ANISOTROPIC THERMAL CONDUCTIVITY IN THE APPARATUS INSULATION FOR SUBLIMATION GROWTH OF SIC  

E-Print Network [OSTI]

INFLUENCE OF ANISOTROPIC THERMAL CONDUCTIVITY IN THE APPARATUS INSULATION FOR SUBLIMATION GROWTH insulation for sublimation growth of SiC: Numerical investigation of heat transfer J¨urgen Geiser, Olaf Klein). As it is not unusual for the thermal insulation of PVT growth apparatus to possess an anisotropic thermal conductivity

128

ENS'07 Paris, France, 3-4 December 2007 MEASUREMENTS OF THERMAL CONDUCTIVITY OF ALUMINUM NANOPOWDERS  

E-Print Network [OSTI]

ENS'07 Paris, France, 3-4 December 2007 MEASUREMENTS OF THERMAL CONDUCTIVITY OF ALUMINUM spectroscopy (PAS) as a powerful technique to estimate thermal properties of aluminum nanosized powders. Aluminum nanopowders are considered as effective constituents of energetic materials. Thermal conductivity

Paris-Sud XI, Université de

129

Thermal conductance of buckled carbon nanotubes Fumio Nishimura1  

E-Print Network [OSTI]

with the strain energy generated in the buckle. Despite the highly stained deformation, the thermal resistance have motivated applications of carbon nanotubes as thermal interface materials [4-8] and additives in nanocomposites [9-12], in practice, one needs to consider various thermal resistances that manifest in the actual

Maruyama, Shigeo

130

Thermal Conduction Path Analysis in 3-D ICs Boris Vaisband1  

E-Print Network [OSTI]

in the temperature and thermal resistance of up to, respectively, 20% and 28%. As confirmed by simulation, those [9], [10]. Thermal flow in materials is described by the Fourier Law, q = -k · T . (1) Thermal-D stack. through a unit of area) q [ W m2 ], the thermal conductivity, a property of the material k

Friedman, Eby G.

131

Interfacial thermal conductance in spun-cast polymer films and polymer brushes  

E-Print Network [OSTI]

represents the length of a material of thermal conduc- tivity providing an equivalent thermal resistance inorganic materials and anharmonic polymers have potentially intriguing thermal transport behavior. The low. This requirement proves challenging for low thermal conductivity materials like amorphous polymers. The effective

Braun, Paul

132

How Does Folding Modulate Thermal Conductivity of Graphene? Nuo Yang1,2  

E-Print Network [OSTI]

of thermal conductivity is due to scattering of low frequency phonons by the folds. Our results suggest dimensional materials. Keywords Folded graphene ribbon, thermal conductivity, phonon transport, scattering #12 conductivity of low-dimensional silicon and carbon materials11 and graphene ribbons12 were studied by EMD

Li, Baowen

133

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

DOE Patents [OSTI]

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.

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

1992-04-07T23:59:59.000Z

134

Thermal conductivity, electrical resistivity, and permeability of saturated soils at various porosities  

E-Print Network [OSTI]

of Ottawa Sand . 4. Thermal Conductivity Data Analysis 5. Thermal Conductivity of Reference Materials 6. DC Resistivity Data with Plate Electrode System for Kaolinite at Porosity of 49% PAGE 48 52 54 66 71 AC Resistivity Data for Kaolinite... THERMAL CONDUCTIVITY, ELECTRICAL RESISTIVITY, AND PERMEABILITY OF SATURATED SOILS AT VARIOUS POROSITIES A Thesis by JAMES KEITH ENDERBY Submitted to the Graduate College of Texas ARM University in Partial fulfillment of the requirement...

Enderby, James Keith

2012-06-07T23:59:59.000Z

135

Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski, Et Al., 2002)  

Open Energy Info (EERE)

2) 2) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove 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 location. Drilling of the test well was completed in the fall of 2001 and results are currently being evaluated. The total depth of the well is 598 m with a non-equilibrated maximum temperature probably in the range of 157degrees C and a very complicated geologic structure.

136

Thermal Gradient Holes At Tungsten Mountain Area (Kratt, Et Al., 2008) |  

Open Energy Info (EERE)

Kratt, Et Al., 2008) Kratt, Et Al., 2008) Exploration Activity Details Location Tungsten Mountain Area Exploration Technique Thermal 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 the range front. These holes approached or exceeded 300 m in depth and all holes encountered hot water and/or steam. Despite the high temperatures encountered at relatively shallow depths, there are no active geothermal features such as hot springs or steam vents at the surface. The presence of small outcrops of argillic alteration containing anomalous gold attracted the interest of exploration geologists. References Christopher Kratt, Mark Coolbaugh, Chris Sladek, Rick Zehner, Robin

137

Thermal Gradient Holes At Chena Area (Erkan, Et. Al., 2008) | Open Energy  

Open Energy Info (EERE)

Chena Area (Erkan, Et. Al., Chena Area (Erkan, Et. Al., 2008) Exploration Activity Details Location Chena Area Exploration Technique Thermal Gradient 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 unrecoverable (Grant et al., 1982). One of the best ways to mitigate this effect is to use multi-stage drilling (White et al., 1975; Grant et al., 1982). This type of drilling was applied at Chena and its usefulness in understanding the natural flow regimes is demonstrated. Here, we illustrate how high-quality equilibrium temperature logs can often be used to identify permeable fractures. The independent interpretations of flow regimes based on temperature-depth curves and the

138

Thermal Gradient Holes At Tungsten Mountain Area (Shevenell, Et Al., 2008)  

Open Energy Info (EERE)

Shevenell, Et Al., 2008) Shevenell, Et Al., 2008) Exploration Activity Details Location Tungsten Mountain Area Exploration Technique Thermal Gradient 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 geothermal community. Exploration holes at Tungsten Mountain and McGuiness Hills (Figure 1) in 2004 and 2005 encountered hot water and steam at depths of meters with fluid geothermometry indicating reservoir temperatures of 170 to 200oC. More information can be obtained from the Nevada Bureau of Mines and Geology web site (www.nbmg.unr.edu/geothermal/gtmap.pdf), and from a PowerPoint presentation titled 'Geothermal Exploration Short Stories' posted on the Geothermal Resources Council web site

139

Evidence of Magnetic Breakdown on the Defects With Thermally Suppressed Critical Field in High Gradient SRF Cavities  

SciTech Connect (OSTI)

At SRF 2011 we presented the study of quenches in high gradient SRF cavities with dual mode excitation technique. The data differed from measurements done in 80's that indicated thermal breakdown nature of quenches in SRF cavities. In this contribution we present analysis of the data that indicates that our recent data for high gradient quenches is consistent with the magnetic breakdown on the defects with thermally suppressed critical field. From the parametric fits derived within the model we estimate the critical breakdown fields.

Eremeev, Grigory [JLAB; Palczewski, Ari [JLAB

2013-09-01T23:59:59.000Z

140

Methods for increasing the thermal conductivity of ultra-high molecular weight polyethylene (UHMWPE)  

E-Print Network [OSTI]

A two-part study was conducted to determine methods for producing ultra-high molecular weight polyethylene with high thermal conductivity by way of polymer chain orientation. The first portion of this report surveys current ...

Miler, Josef L

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Experimental investigation of plastic finned-tube heat exchangers, with emphasis on material thermal conductivity  

SciTech Connect (OSTI)

In this paper, two modified types of polypropylene (PP) with high thermal conductivity up to 2.3 W/m K and 16.5 W/m K are used to manufacture the finned-tube heat exchangers, which are prospected to be used in liquid desiccant air conditioning, heat recovery, water source heat pump, sea water desalination, etc. A third plastic heat exchanger is also manufactured with ordinary PP for validation and comparison. Experiments are carried out to determine the thermal performance of the plastic heat exchangers. It is found that the plastic finned-tube heat exchanger with thermal conductivity of 16.5 W/m K can achieve overall heat transfer coefficient of 34 W/m{sup 2} K. The experimental results are compared with calculation and they agree well with each other. Finally, the effect of material thermal conductivity on heat exchanger thermal performance is studied in detail. The results show that there is a threshold value of material thermal conductivity. Below this value improving thermal conductivity can considerably improve the heat exchanger performance while over this value improving thermal conductivity contributes very little to performance enhancement. For the finned-tube heat exchanger designed in this paper, when the plastic thermal conductivity can reach over 15 W/m K, it can achieve more than 95% of the titanium heat exchanger performance and 84% of the aluminum or copper heat exchanger performance with the same dimension. (author)

Chen, Lin; Li, Zhen; Guo, Zeng-Yuan [Department of Engineering Mechanics, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)

2009-07-15T23:59:59.000Z

142

ENHANCED THERMAL CONDUCTIVITY IN NANOFLUIDS UNDER THE ACTION OF OSCILLATING FORCE FIELDS  

E-Print Network [OSTI]

. Active control of transport coefficients. Nanocolloïds. Cooling system Introduction Nanofluids (EastmanENHANCED THERMAL CONDUCTIVITY IN NANOFLUIDS UNDER THE ACTION OF OSCILLATING FORCE FIELDS Clément Le forces in the radio frequency and microwave ranges, we show that the thermal conductivity of nanofluids

Paris-Sud XI, Université de

143

Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies of Percolation of Microemulsions  

E-Print Network [OSTI]

Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies studied below and above the percolation thresholds by electrical conductivity, near-infrared absorption. In this work the structure of microemulsions was investigated by using the near-IR absorption and thermal lens

Reid, Scott A.

144

Electrical resistivity and thermal conductivity of liquid Fe alloys at high P and T, and  

E-Print Network [OSTI]

Electrical resistivity and thermal conductivity of liquid Fe alloys at high P and T, and heat flux to crystallize (1, 4). Existing estimates of thermal conductivity (kel) and electrical resistivity (el) of Earth of electrical resistivity to temperature, its invariability along and across the Fe liquidus, and adherence

Steinle-Neumann, Gerd

145

Thermal conductance of metal-diamond interfaces at high pressure Gregory T. Hohensee  

E-Print Network [OSTI]

are concerned with the exchange of thermal energy across an interface between two materials. This topic-nonmetal interface, a two-temperature model predicts a thermal resistance of Rep = 1/ gL in series with the phononThermal conductance of metal-diamond interfaces at high pressure Gregory T. Hohensee Department

Cahill, David G.

146

Generalized model of thermal boundary conductance between SWNT and surrounding supercritical Lennard-Jones fluid  

E-Print Network [OSTI]

of the promising applications is to use SWNTs as additives to enhance thermal conductivity of composite materials of the composite can be strongly influenced by thermal boundary resistance (TBR) between carbon nanotubes, it is essential to understand TBR. Thermal boundary resistance, with its importance in small scale, has been

Maruyama, Shigeo

147

Communication: Minimum in the thermal conductivity of supercooled water: A computer simulation study  

SciTech Connect (OSTI)

We report the results of a computer simulation study of the thermodynamic properties and the thermal conductivity of supercooled water as a function of pressure and temperature using the TIP4P-2005 water model. The thermodynamic properties can be represented by a two-structure equation of state consistent with the presence of a liquid-liquid critical point in the supercooled region. Our simulations confirm the presence of a minimum in the thermal conductivity, not only at atmospheric pressure, as previously found for the TIP5P water model, but also at elevated pressures. This anomalous behavior of the thermal conductivity of supercooled water appears to be related to the maximum of the isothermal compressibility or the minimum of the speed of sound. However, the magnitudes of the simulated thermal conductivities are sensitive to the water model adopted and appear to be significantly larger than the experimental thermal conductivities of real water at low temperatures.

Bresme, F., E-mail: f.bresme@imperial.ac.uk [Chemical Physics Section, Department of Chemistry, Imperial College, London SW7 2AZ, United Kingdom and Department of Chemistry, Norwegian University of Science and Technology, Trondheim 7491 (Norway); Biddle, J. W.; Sengers, J. V.; Anisimov, M. A. [Institute for Physical Science and Technology, and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)] [Institute for Physical Science and Technology, and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)

2014-04-28T23:59:59.000Z

148

G-Plus report to Owens Corning-thermal conductivity Measurements of Fiberglass  

SciTech Connect (OSTI)

Fiberglass made by Owens Corning is being used in noise reduction of automobile exhaust system. Specifically, the glass fibers are packed inside the muffler to achieve the desired acoustic effect. A secondary benefit of the fibers is to serve as a thermal insulation. Because of this insulating property, the glass fibers can serve to reduce the temperature of the muffler shell. This in turn reduces the need for heat shields around mufflers and reduces the amount of exterior temperature accelerated corrosion of the muffler shell, especially in the winter ''salt belts'' where large amounts of salt are placed on highways to minimize the safety impact of snow and ice. In addition, for some applications the use of the fiberglass could allow the use of lighter weight carbon based polymer composite materials in place of steel for muffler shells. However, in order to properly design exhaust systems without heat shields or to take advantage of new materials, the thermal conductivity of the fiberglass material at operating temperatures (for some applications above 750 C) must be known. We selected two types of Owens Corning glass fibers, 17 {micro}m and 24 {micro}m in diameter, for this study. There are some room temperature thermal conductivity data for the fiberglass, but high temperature data are not available. Based on the thermal radiation model, thermal conductivity should increase rapidly at high temperature, providing less thermal insulation. In addition, thermal conductivity depends on packing density of the glass fibers. We will study the effect of packing density on thermal conductivity. Another issue is that the glass fiber conducts heat better along the fiber, while the conduction across the fibers is poor, because thermal conduction from one fiber to another has to go through an interface with thermal resistance. In fiberglass, most fibers are not in good contact with the surrounding fibers, thus, most heat transfer is dependent on the thermal radiation effect. Among the many methods of measuring thermal conductivity, only a few can be used for glass fibers. The traditional heat flow meter is used in testing thermal insulations near room temperature. At higher temperatures this method cannot be used due to material and instrument limitations. Our plan is to use a transient plane source (TPS) method to measure thermal conductivity directly. The advantage of the TPS method is that measurements can be taken at over 700 C, and covers the temperature of the automobile exhausts. The following is a report for the G-Plus project conducted at ORNL to apply the TPS method to characterizing the thermal conductivity of two types of fiberglass and also the effect of packing density.

Wang, H

2003-04-15T23:59:59.000Z

149

Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites  

SciTech Connect (OSTI)

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.

Liu, Ying [Clemson University] [Clemson University; Huang, Jingsong [ORNL] [ORNL; Yang, Bao [University of Maryland] [University of Maryland; Sumpter, Bobby G [ORNL] [ORNL; Qiao, Rui [Clemson University] [Clemson University

2014-01-01T23:59:59.000Z

150

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

SciTech Connect (OSTI)

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.

Chai, Jeng-Da, E-mail: jdchai@phys.ntu.edu.tw [Department of Physics, Center for Theoretical Sciences, and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)] [Department of Physics, Center for Theoretical Sciences, and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2014-05-14T23:59:59.000Z

151

Simultaneous measurement of the thermal conductivity and thermal diffusivity of unconsolidated materials by the transient hot wire method  

Science Journals Connector (OSTI)

This paper describes a new design for the transient hot wire method that can obtain the thermal conductivity and thermal diffusivity of unconsolidated materials. In this method the thermal conductivity is determined from the slope of the temperature rise versus time of an electrically heated wire. The temperature rise is detected as the unbalanced voltage of a precision Wheatstone bridge. This voltage is read by a microcomputer via a high?speed analog?to?digital converter. The instrument was designed so that measurements can be taken over a temperature range of 20–200?°C and a pressure range of atmospheric down to 10 mTorr. Tests using glycerin indicate an accuracy of 1% for the conductivity and 6% for the diffusivity and a precision of 0.4% for the conductivity and 4.5% for the diffusivity. Measurements have also been made on materials such as 50?? glass beads and unconsolidated spent oil shale.

Greg C. Glatzmaier; W. Fred Ramirez

1985-01-01T23:59:59.000Z

152

Phonon-cavity-enhanced low-temperature thermal conductance of a semiconductor nanowire with narrow constrictions  

Science Journals Connector (OSTI)

We study the effect of the phonon cavity lying in a narrow constriction of a semiconductor nanowire on the ballistic phonon thermal conductance at low temperatures. At higher temperatures, the thermal conductance of the nanowire with phonon cavity is lower than that of the nanowire without phonon cavity since more discontinuous interfaces scatter phonons. On the contrary, it is found that the cavity can enhance the thermal conductance at very low temperatures despite phonons are scattered by its interfaces. The enhancement originates from the coupling between more excited cavity modes in the phonon cavity and phonon modes in the constrictions.

Wei-Qing Huang; Gui-Fang Huang; Ling-Ling Wang; Bai-Yun Huang

2007-06-27T23:59:59.000Z

153

Serpentine Thermal Coupling Between a Stream and a Conducting Body  

SciTech Connect (OSTI)

Here we document the effect of flow configuration on the heat transfer performance of a serpentine shaped stream embedded in a conducting solid. Several configurations with fixed volume of fluid are considered: U-shaped with varying spacing between the parallel portions of the U, serpentine shapes with three elbows, and conducting soil with several parallelepipedal shapes. We show that the spacing must be greater than a critical value in order for the heat transfer density of the stream-solid configuration to be the highest that it can be. Spacings larger than this critical value do not yield improvements in heat transfer density. We also show that even though the heat transfer is time dependent, the stream-solid configuration has an effective number of heat transfer units Ntu that is nearly constant in time. The larger Ntu values correspond to the configurations with greater heat transfer density.

Kobayashi, H.; Lorente, S.; Anderson, R.; Bejan, A.

2012-02-15T23:59:59.000Z

154

EVALUATION OF THERMAL CONDUCTIVITY OF INSTALLED-IN-PLACE POLYURETHANE FOAM INSULATION BY EXPERIMENT AND ANALYSIS  

SciTech Connect (OSTI)

In the thermal analysis of the 9977 package, it was found that calculated temperatures, determined using a typical thermal analysis code, did not match those measured in the experimental apparatus. The analysis indicated that the thermal resistance of the overpack in the experimental apparatus was less than that expected, based on manufacturer's reported value of thermal conductivity. To resolve this question, the thermal conductivity of the installed foam was evaluated from the experimental results, using a simplified analysis. This study confirmed that the thermal resistance of the experimental apparatus was lower than that which would result from the manufacturer's published values for thermal conductivity of the foam insulation. The test package was sectioned to obtain samples for measurement of material properties. In the course of the destructive examination a large uninsulated region was found at the bottom of the package, which accounted for the anomalous results. Subsequent measurement of thermal conductivity confirmed the manufacturer's published values. The study provides useful insight into the use of simplified, scoping calculations for evaluation of thermal performance of packages.

Smith, A; Bruce Hardy, B; Kurt Eberl, K; Nick Gupta, N

2007-12-05T23:59:59.000Z

155

Temperature, thermal-conductivity, and heat-flux data,Raft River area,  

Open Energy Info (EERE)

Temperature, thermal-conductivity, and heat-flux data,Raft River area, Temperature, thermal-conductivity, and heat-flux data,Raft River area, Cassia County, Idaho (1974-1976) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Temperature, thermal-conductivity, and heat-flux data,Raft River area, Cassia County, Idaho (1974-1976) Details Activities (1) Areas (1) Regions (0) Abstract: Basin and Range Province; Cassia County Idaho; economic geology; exploration; geophysical surveys; geothermal energy; heat flow; heat flux; Idaho; North America; Raft River basin; south-central Idaho; surveys; temperature; thermal conductivity; United States; USGS Author(s): Urban, T.C.; Diment, W.H.; Nathenson, M.; Smith, E.P.; Ziagos, J.P.; Shaeffer, M.H. Published: Open-File Report - U. S. Geological Survey, 1/1/1986 Document Number: Unavailable

156

Thermal conductivity of fluids containing suspension of nanometer-sized particles  

E-Print Network [OSTI]

Nanofluids, which are fluids containing suspension of nanometer-sized particles, have been reported to possess substantially higher thermal conductivity than their respective base fluids. This thesis reports on an experimental ...

Ma, Jack Jeinhao

2006-01-01T23:59:59.000Z

157

Thermal conductivity enhancement of Ag nanowires on an organic phase change material  

Science Journals Connector (OSTI)

One of the greatest challenges in the application of organic phase change materials (PCMs) is to increase their thermal conductivity while maintaining high phase change enthalpy. 1-Tetradecanol/Ag nanowires compo...

J. L. Zeng; Z. Cao; D. W. Yang; L. X. Sun…

2010-07-01T23:59:59.000Z

158

Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube  

DOE Patents [OSTI]

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.

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

2008-03-25T23:59:59.000Z

159

Effective thermal conductivity measurements relevant to deep borehole nuclear waste disposal  

E-Print Network [OSTI]

The objective of this work was to measure the effective thermal conductivity of a number of materials (particle beds, and fluids) proposed for use in and around canisters for disposal of high level nuclear waste in deep ...

Shaikh, Samina

2007-01-01T23:59:59.000Z

160

An Analytical Model for Determining the Thermal Conductivity of Closed-Cell Foam Insulation  

Science Journals Connector (OSTI)

The purpose of this paper is to present analytical methods and some preliminary test results for determining the thermal conductivity and net heat flow in closed-cell foam materials used as cryogenic insulation. ...

M. B. Hammond Jr.

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium Reduction of Polymer-  

E-Print Network [OSTI]

Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium-assembly of mesoporous silica followed by magnesium reduction. The periodic ordering of pores in mesoporous silicon

Pilon, Laurent

162

Gallium arsenide thermal conductivity and optical phonon relaxation times from first-principles calculations  

E-Print Network [OSTI]

In this paper, thermal conductivity of crystalline GaAs is calculated using first-principles lattice dynamics. The harmonic and cubic force constants are obtained by fitting them to the force-displacement data from density ...

Luo, Tengfei

163

Lattice thermal conductivity of Bi, Sb, and Bi-Sb alloy from first principles  

E-Print Network [OSTI]

Using first principles, we calculate the lattice thermal conductivity of Bi, Sb, and Bi-Sb alloys, which are of great importance for thermoelectric and thermomagnetic cooling applications. Our calculation reveals that the ...

Lee, Sangyeop

164

Viscosity and thermal conductivity effects at first-order phase transitions in heavy-ion collisions  

SciTech Connect (OSTI)

Effects of viscosity and thermal conductivity on the dynamics of first-order phase transitions are studied. The nuclear gas-liquid and hadron-quark transitions in heavy-ion collisions are considered. We demonstrate that at nonzero thermal conductivity, {kappa} {ne} 0, onset of spinodal instabilities occurs on an isothermal spinodal line, whereas for {kappa} = 0 instabilities take place at lower temperatures, on an adiabatic spinodal.

Voskresensky, D. N., E-mail: D.Voskresensky@gsi.de [National Research Nuclear University 'MEPhI' (Russian Federation); Skokov, V. V., E-mail: V.Skokov@gsi.de [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany)

2012-06-15T23:59:59.000Z

165

Thermal contact conductance of metallic coated superconductor/copper interfaces at cryogenic temperatures  

E-Print Network [OSTI]

THERMAL CONTACT CONDUCTANCE OF METALLIC COATED SUPERCONDUCTOR/COPPER INTERFACES AT CRYOGENIC TEMPERATURES A Thesis by JAY MATTHEW OCHTERBECK Submitted to the 0%ce of Graduate Studies of Texas AJrM IJniversity in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1990 Major Subject: Mechanical Engineering THERMAL CONTACT CONDUCTANCE OF METALLIC COATED SUPERCONDUCTOR/COPPER INTERFACES AT CRYOGENIC TEMPERATURES A Thesis JA'r '(IATTHEW OCHTERBECK Approved...

Ochterbeck, Jay Matthew

2012-06-07T23:59:59.000Z

166

Size-dependent interface phonon transmission and thermal conductivity of nanolaminates  

E-Print Network [OSTI]

resistance between different materials exists since the interface breaks the regular lattice structure and superlattices as the interface distance or periodic thickness reduces. The interface thermal resistance has beenSize-dependent interface phonon transmission and thermal conductivity of nanolaminates L. H. Liang

Li, Baowen

167

Measurement of Thermal Conductivity of PbTe Nanocrystal Coated Glass Fibers by the 3 Method  

E-Print Network [OSTI]

and high aspect ratio result in a significant thermal radiation effect. We simulate the experiment using such as automobile exhaust pipes, power plant steam pipes, manufacturing industry cooling pipes, and so forth. Our the radiation effect and extract the thermal conductivity at the single fiber level. Our simulation method

Ruan, Xiulin

168

Propagation of three--dimensional Alfv'en waves in a stratified, thermally conducting solar wind  

E-Print Network [OSTI]

Propagation of three--dimensional Alfv'en waves in a stratified, thermally conducting solar wind S to the well--known thermal expansion of the solar corona [Parker, 1958, 1963, 1991]. In particular Alfv'en waves in the solar atmosphere and wind, taking into account relevant physical effects

169

Iodine doping effects on the lattice thermal conductivity of oxidized polyacetylene nanofibers  

SciTech Connect (OSTI)

Thermal transport in oxidized polyacetylene (PA) nanofibers with diameters in the range between 74 and 126?nm is measured with the use of a suspended micro heater device. With the error due to both radiation and contact thermal resistance corrected via a differential measurement procedure, the obtained thermal conductivity of oxidized PA nanofibers varies in the range between 0.84 and 1.24?W?m{sup ?1}?K{sup ?1} near room temperature, and decreases by 40%–70% after iodine doping. It is also found that the thermal conductivity of oxidized PA nanofibers increases with temperature between 100 and 350?K. Because of exposure to oxygen during sample preparation, the PA nanofibers are oxidized to be electrically insulating before and after iodine doping. The measurement results reveal that iodine doping can result in enhanced lattice disorder and reduced lattice thermal conductivity of PA nanofibers. If the oxidation issue can be addressed via further research to increase the electrical conductivity via doping, the observed suppressed lattice thermal conductivity in doped polymer nanofibers can be useful for the development of such conducting polymer nanostructures for thermoelectric energy conversion.

Bi, Kedong, E-mail: lishi@mail.utexas.edu, E-mail: kedongbi@seu.edu.cn [Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Weathers, Annie; Pettes, Michael T.; Shi, Li, E-mail: lishi@mail.utexas.edu, E-mail: kedongbi@seu.edu.cn [Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Matsushita, Satoshi; Akagi, Kazuo [Department of Polymer Chemistry, Kyoto University, Kyoto 615-8510 (Japan); Goh, Munju [Department of Polymer Chemistry, Kyoto University, Kyoto 615-8510 (Japan); Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), Eunha-ri san 101, Bondong-eup, Wanju-gun, Jeolabuk-do 565-905 (Korea, Republic of)

2013-11-21T23:59:59.000Z

170

Effective thermal conductivity for anisotropic granular porous media using fractal concepts  

SciTech Connect (OSTI)

The use of granular porous media in chemical processes, thermal insulation, heat exchangers, and nuclear reactor fuel rods has led to the development of correlations for thermophysical properties, such as thermal conductivity. These correlations are essential in the prediction of heat and mass transfer involving porous media. Analytical correlations are derived for the effective thermal conductivity of anisotropic, Granular Porous Media (GPM). The correlations proposed, which can be apply in general to any porous media material, are used to determine the effective thermal conductivity of GPM that are formed by semi-cylindrical ice particles. Pictures of the cross-section of GPM provide digital data for measuring local fractal dimensions. Local fractal dimensions are used to determine an equivalent three-dimensional Representative Unit Cell (RUC) for the GPM considered. A simplified analysis of heat conduction at the RUC level provide an analytical expression for the effective heat transfer coefficient. Estimates for the effective thermal conductivity by the use of the models are discussed and compared with various models known in literature. Finally, results for anisotropic thermal conductivities, which are obtained by the use of fractal correlations, are discussed.

Sabau, A.S.; Tao, Y.X.; Liu, G.; Vidhuvalavan, G.

1997-07-01T23:59:59.000Z

171

ESTIMATION OF IN-SITU THERMAL CONDUCTIVITIES FROM TEMPERATURE GRADIENT MEASUREMENTS  

E-Print Network [OSTI]

in the fluid, and the rate of heat transfer from the fluidSpi11ette t A.G~t "Heat Transfer During Hot Fluid Injectionin the fluid is solved, the heat transfer at the wall is

Hoang, V.T.

2010-01-01T23:59:59.000Z

172

PHYSICAL REVIEW B 90, 174107 (2014) High-throughput computational screening of thermal conductivity, Debye temperature, and  

E-Print Network [OSTI]

for the past few decades [6]. Low thermal conductivity materials constitute the basis of a new generation such as the Debye temperature and the thermal conductivity of materials. We demonstrate that the AGL method, which ranking of the thermal conductivity for several different classes of semiconductor materials

Curtarolo, Stefano

173

Thermal Conduction in Suspended Graphene Layers A. A.BALANDIN, S. GHOSH, D. L. NIKA AND E. P. POKATILOV  

E-Print Network [OSTI]

' properties. Materials with very high or very low thermal conductivities attract particular attention due and engineering research communities to the thermal conductivity of materials. This is explained by both in its atomic structure and the knowledge of thermal conductivity can shed light on many other materials

174

Suppression of thermal conductivity in InxGa12xN alloys by nanometer-scale disorder  

E-Print Network [OSTI]

power requires low lattice thermal conductivity while maintaining high mobility of the charge carriers. The binary InN and GaN materials have high ther- mal conductivity materials9­14 (the room-temperature thermalSuppression of thermal conductivity in InxGa12xN alloys by nanometer-scale disorder T. Tong,1,a) D

Wu, Junqiao

175

Reduction of thermal conductivity of anharmonic lattices Lei Wang1 and Baowen Li1,2,3,  

E-Print Network [OSTI]

for constructing a material with ultra low thermal conductivity is still not available. As a simple. INTRODUCTION Thermal conductivity is one of the most fundamental and important properties of materials.1 heat dissipation. In the former case, one needs to have a very low thermal conductivity, while

Li, Baowen

176

Analysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp characteristics  

E-Print Network [OSTI]

injection which we term "thermal impact" , the ther- mal conductivity of the active region is estimatedAnalysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp; published online 21 September 2006 The thermal conductivity of self-organized quantum dot QD active regions

Klotzkin, David

177

Thermal conductance of solid-liquid interfaces Scott Huxtable, Zhenbin Ge, David G. Cahill  

E-Print Network [OSTI]

thermal conductivity in nanostructured materials ­ improved thermoelectric energy conversion improved/surfactant/water PMMA/Al2O3 nanotube/alkane #12;Modulated pump-probe apparatus f=10 MHz rf lock-in #12;Solid · Cooling rate (RC time constant) gives interface conductance G = 12 MW m-2 K-1G = 12 MW m K #12;Application

Braun, Paul

178

An apparatus for the measurement of thermal conductivity of liquid neon  

E-Print Network [OSTI]

) ~ 4 Lochtermann, Cryog nics Q, 45 (1963) ~ conductivity of liquid neon. The thermal conductivity measurements will be made using the "hot plate" method used by Grenier for measurements in liquid helium. The test cell to be used is shown 1n figure... for the experiment shown in figure 1 follows the basic design used by Grenier f' or measure- 5 ments of' the thermal conductivity of liquid. helium. The hot plate, Pl, is supported within the guard ring, P , by means of a stainless steel tube. The guard ring...

Jensen, Jerald Norman

2012-06-07T23:59:59.000Z

179

Determination of Thermal Contact Conductance of Metal Tabs for Battery Ultrasonic Welding Process  

SciTech Connect (OSTI)

A new experimental apparatus and data analysis algorithm were used to determine the thermal contact conductance between 0.2-mm-thick pure aluminum battery tabs as a function of contact pressure from 3.6 to 14.4 MPa. Specimens were sandwiched between one optically transparent and one infrared (IR) transparent glass windows, and heated up from one side by an intense short pulse of flash light. The temperature transient on the other side was measured by an IR camera. In order to determine the thermal contact conductance, two experiment configurations having different number of Al specimen layers were used. Numerical heat conduction simulations showed that the thermal contact conductance strongly depended on the ratio of the maximum temperature rise between the two configurations. Moreover, this ratio was not sensitive to the uncertainties of other thermal properties. Through the simulation results, a simple correlation between the gap conductance and the ratio was established. Therefore, once the ratio of the temperature rise between two configurations was experimentally measured, the thermal contact conductance could be readily determined from the correlation. The new method was fast and robust. Most importantly, the data analysis algorithm improved the measurement accuracy by considerably reducing the uncertainties associated with the thermophysical properties of materials and measurement system.

Chen, Jian [ORNL] [ORNL; Zhang, Wei [ORNL] [ORNL; Yu, Zhenzhen [ORNL] [ORNL; Feng, Zhili [ORNL] [ORNL

2012-01-01T23:59:59.000Z

180

A model of the large hydraulic gradient at Yucca Mountain, Nevada Test Site, based on hydraulic conductivity contrasts between Cenozoic and Paleozoic rocks  

E-Print Network [OSTI]

A MODEL OF THE LARGE HYDRAULIC GRADIENT AT YUCCA MOUNTAIN, NEVADA TEST SITE, BASED ON HYDRAULIC CONDUCTIVITY CONTRASTS BETWEEN CENOZOIC AND PALEOZOIC ROCKS A Thesis ERIC WILLIAM STROM Submitted to the Offic of Graduate Studies of Texas A.... 4m W&~~ &&go~'~o~~i gp ??g Y, ) 4r y. odtli' ~ 6. A MODEL OF THE LARGE HYDRAULIC GRADIENT AT YUCCA MOUNTAIN, NEVADA TEST SITE, BASED ON HYDRAULIC CONDUCTIVITY CONTRASTS BETWEEN CENOZOIC AND PALEOZOIC ROCKS A Thesis ERIC WILLIAM STROM...

Strom, Eric William

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

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

SciTech Connect (OSTI)

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.

Mamand, S.M., E-mail: soran.mamand@univsul.net [Department of Physics, College of Science, University of Sulaimani, Sulaimanyah, Iraqi Kurdistan (Iraq); Omar, M.S. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)] [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Muhammad, A.J. [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)] [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)

2012-05-15T23:59:59.000Z

182

An Analytical Study Of A 2-Layer Transient Thermal Conduction Problem As  

Open Energy Info (EERE)

Analytical Study Of A 2-Layer Transient Thermal Conduction Problem As Analytical Study Of A 2-Layer Transient Thermal Conduction Problem As Applied To Soil-Temperature Surveys Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: An Analytical Study Of A 2-Layer Transient Thermal Conduction Problem As Applied To Soil-Temperature Surveys Details Activities (0) Areas (0) Regions (0) Abstract: The soil temperature survey is an inexpensive exploration method in groundwater and geothermal resource investigations. In its simplest form, temperatures measured in shallow holes are analyzed to deduce variations in material properties. Typical interpretation schemes are based on simple, one-layer solutions to the Fourier conduction equation using the annual solar cycle as a surface heat source. We present a solution to the

183

Composite material having high thermal conductivity and process for fabricating same  

DOE Patents [OSTI]

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.

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

1998-07-21T23:59:59.000Z

184

Composite material having high thermal conductivity and process for fabricating same  

DOE Patents [OSTI]

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.

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

1998-01-01T23:59:59.000Z

185

Thermal Conductivity of Hexagonal Close-Packed Solid Helium Four at High Densities  

Science Journals Connector (OSTI)

Thermal conductivity measurements between 1.1° K and 7° K have been made on solid helium samples grown under constant pressures from 185 atm to 1050 atm. At high temperatures the phonon mean free path l¯ for the highest conductivity samples at six different densities is in good agreement with the expression, l¯=Aexp(?DbT), where ?D is the Debye temperature at T=0° K, A=2.5×10-8 cm, b=2.13. Several samples grown from gas repurified by an adsorption trap exhibited mean free paths in agreement with this expression over almost four orders of magnitude. Slightly impure samples showed a considerable attenuation in the peak thermal conductivity at pressures above 320 atm. There was some evidence for anisotropy of the thermal conductivity in the umklapp region and for Poiseuille flow in the low-temperature region, but both these effects were considerably smaller than reported by other investigators for specimens grown at lower pressures.

W. D. Seward, D. Lazarus, and S. C. Fain, Jr.

1969-02-05T23:59:59.000Z

186

Particle Swarm Optimization and Gradient Descent Methods for Optimization of PI Controller for AGC of Multi-area Thermal-Wind-Hydro Power Plants  

Science Journals Connector (OSTI)

The automatic generation control (AGC) of three unequal interconnected Thermal, Wind and Hydro power plant has been designed with PI controller. Further computational intelligent technique Particle Swarm Optimization and conventional Gradient Descent ... Keywords: Automatic generation control, Particle swarm optimization, Gradient Descent method, Generation rate constraint, Area control error, Wind energy conversion system

Naresh Kumari; A N. Jha

2013-04-01T23:59:59.000Z

187

FAST STATIC AND DYNAMIC GRID LEVEL THERMAL SIMULATION CONSIDERING TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF SILICON  

E-Print Network [OSTI]

heat diffusion equation has been conventionally handled by grid-grids and an approximate delta function simulating a point heatgrid size of 64×64. To obtain transient thermal mask an impulse heat

Ziabari, Amirkoushyar

2012-01-01T23:59:59.000Z

188

FAST STATIC AND DYNAMIC GRID LEVEL THERMAL SIMULATION CONSIDERING TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF SILICON  

E-Print Network [OSTI]

is based on an equivalent circuit of thermal resistances andof convection resistance to 0.13 K/W. This is equivalent toequivalent convection coefficient. h = 1/(R × A) The convection resistance

Ziabari, Amirkoushyar

2012-01-01T23:59:59.000Z

189

Improvement of the identification of multiwall carbon nanotubes carpet thermal conductivity by pulsed photothermal method  

SciTech Connect (OSTI)

Thermal properties in multiwall carbon nanotubes carpets and micro-devices are investigated using a nanosecond photothermal method. Gradually, the identification model and experimental protocol are performed to increase the method accuracy for the thermal conductivity determination. In the experimental protocol, a nanosecond UV monopulse laser beam is used to heat the surface of a multilayer (600 nm of Ti/20 {mu}m of carbon nanotube carpet) sample. In the 1D identification model with two layers and a thermal contact resistance, the effect of the laser excitation temporal shape is taken into account. In this study, this first approach allows to improve the accuracy of apparent thermal conductivity measurements of multiwall carbon nanotubes carpet. The carbon nanotubes carpet apparent thermal conductivity value went from being to 180 {+-} 5 W Multiplication-Sign m{sup -1} Multiplication-Sign K{sup -1}. In the second approach, two laser beams are coupled in order to increase the interaction time duration from 27 ns to 60 ns. It becomes possible to probe different depths in the carpet. The obtained value (180 W Multiplication-Sign m{sup -1} Multiplication-Sign K{sup -1}) confirms the pulsed photothermal method consistency for porous samples. Finally, assuming that the carbon nanotubes are parallel and without any defects, the equivalent intrinsic thermal conductivity of a single carbon nanotube is estimated to be around 3600 W Multiplication-Sign m{sup -1} Multiplication-Sign K{sup -1}.

Amin-Chalhoub, E.; Wattieaux, G.; Semmar, N.; Gaillard, M.; Petit, A.; Leborgne, C. [GREMI, Universite d'Orleans, CNRS UMR 6606, 14 rue d'Issoudun, BP 6744, 45067 Orleans (France)

2012-11-01T23:59:59.000Z

190

Amorphization and reduction of thermal conductivity in porous silicon by irradiation with swift heavy ions  

SciTech Connect (OSTI)

In this article, we demonstrate that the thermal conductivity of nanostructured porous silicon is reduced by amorphization and also that this amorphous phase in porous silicon can be created by swift (high-energy) heavy ion irradiation. Porous silicon samples with 41%-75% porosity are irradiated with 110 MeV uranium ions at six different fluences. Structural characterisation by micro-Raman spectroscopy and SEM imaging show that swift heavy ion irradiation causes the creation of an amorphous phase in porous Si but without suppressing its porous structure. We demonstrate that the amorphization of porous silicon is caused by electronic-regime interactions, which is the first time such an effect is obtained in crystalline silicon with single-ion species. Furthermore, the impact on the thermal conductivity of porous silicon is studied by micro-Raman spectroscopy and scanning thermal microscopy. The creation of an amorphous phase in porous silicon leads to a reduction of its thermal conductivity, up to a factor of 3 compared to the non-irradiated sample. Therefore, this technique could be used to enhance the thermal insulation properties of porous Si. Finally, we show that this treatment can be combined with pre-oxidation at 300 Degree-Sign C, which is known to lower the thermal conductivity of porous Si, in order to obtain an even greater reduction.

Newby, Pascal J. [Institut des Nanotechnologies de Lyon, Universite de Lyon, INL-UMR5270, CNRS, INSA de Lyon, Villeurbanne 69621 (France); Institut Interdisciplinaire d'Innovation Technologique (3IT), Universite de Sherbrooke, CNRS UMI-LN2, Sherbrooke, Quebec J1K0A5 (Canada); Canut, Bruno; Bluet, Jean-Marie; Lysenko, Vladimir [Institut des Nanotechnologies de Lyon, Universite de Lyon, INL-UMR5270, CNRS, INSA de Lyon, Villeurbanne 69621 (France); Gomes, Severine [Centre de Thermique de Lyon, Universite de Lyon, CETHIL-UMR5008, CNRS, INSA de Lyon, Villeurbanne 69621 (France); Isaiev, Mykola; Burbelo, Roman [Faculty of Physics, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrs'ka St., Kyiv 01601 (Ukraine); Termentzidis, Konstantinos [Laboratoire LEMTA, Universite de Lorraine-CNRS UMR 7563, 54506 Vandoeuvre-les-Nancy cedex (France); Chantrenne, Patrice [Universite de Lyon, INSA de Lyon, MATEIS-UMR CNRS 5510, Villeurbanne 69621 (France); Frechette, Luc G. [Institut Interdisciplinaire d'Innovation Technologique (3IT), Universite de Sherbrooke, CNRS UMI-LN2, Sherbrooke, Quebec J1K0A5 (Canada)

2013-07-07T23:59:59.000Z

191

Ultra-sensitive thermal conductance measurement of one-dimensional nanostructures enhanced by differential bridge  

Science Journals Connector (OSTI)

Thermal conductivity of one-dimensional nanostructures such as nanowires nanotubes and polymer chains is of significant interest for understanding nanoscale thermal transport phenomena as well as for practical applications in nanoelectronics energy conversion and thermal management. Various techniques have been developed during the past decade for measuring this fundamental quantity at the individual nanostructure level. However the sensitivity of these techniques is generally limited to 1 × 10?9 W/K which is inadequate for small diameter nanostructures that potentially possess thermal conductance ranging between 10?11 and 10?10 W/K. In this paper we demonstrate an experimental technique which is capable of measuring thermal conductance of ?10?11 W/K. The improved sensitivity is achieved by using an on-chip Wheatstone bridge circuit that overcomes several instrumentation issues. It provides a more effective method of characterizing the thermal properties of smaller and less conductive one-dimensional nanostructures. The best sensitivity experimentally achieved experienced a noise equivalent temperature below 0.5 mK and a minimum conductancemeasurement of 1 × 10?11 W/K. Measuring the temperature fluctuation of both the four-point and bridge measurements over a 4 h time period shows a reduction in measured temperature fluctuation from 100 mK to 0.6 mK. Measurement of a 15 nm Genanowire and background conductance signal with no wire present demonstrates the increased sensitivity of the bridge method over the traditional four-point I-V measurement. This ultra-sensitive measurement platform allows for thermal measurements of materials at new size scales and will improve our understanding of thermal transport in nanoscale structures.

Matthew C. Wingert; Zack C. Y. Chen; Shooshin Kwon; Jie Xiang; Renkun Chen

2012-01-01T23:59:59.000Z

192

Technical and economic feasibility of a Thermal Gradient Utilization Cycle (TGUC) power plant  

E-Print Network [OSTI]

has grown in energy technologies that use renewable resources such as solar (thermal conversion, ocean thermal energy conversion, photovoltaics, wind and biomass conversion), geothermal and magnetohydrodynamics (MHD) . A new concept that can...

Raiji, Ashok

1980-01-01T23:59:59.000Z

193

Thermal Conductivity of LiF and NaF and the Ziman Limit  

Science Journals Connector (OSTI)

A model calculation of lattice thermal conductivity is presented and applied to measurements on LiF and NaF crystals of high purity. The treatment is in the spirit of a Callaway analysis, but at a somwhat more fundamental level: The Ziman variational principle for thermal conductivity derived from the phonon Boltzmann equation is used, with the phonon distribution function approximated by a displaced Planck part plus another term reducing the deviation from equilibrium for high-frequency phonons. An isotropic Debye approximation for the phonon spectra of LiF and NaF gives a good fit to the conductivity data, with only two semi-adjustable parameters (Grüneisen constant and a zone-edge longitudinal phonon frequency) for the anharmonic contribution. The most important feature of the calculation is the failure of the thermal conductivity to approach the Ziman limit of resistanceless phonon-phonon N processes. This is due to the important role played by high-frequency phonons in thermal conduction. Even for an infinite perfect crystal at arbitrarily low temperatures, the Ziman limit underestimates the conductivity by at least 50%. If this prediction is correct, it is not a peculiarity of LiF and NaF alone, and should be of importance for the theory of second-sound propagation in insulators.

David Benin

1972-03-15T23:59:59.000Z

194

Temperature dependence of thermal conductivities of coupled rotator lattice and the momentum diffusion in standard map  

E-Print Network [OSTI]

In contrary to other 1D momentum-conserving lattices such as the Fermi-Pasta-Ulam $\\beta$ (FPU-$\\beta$) lattice, the 1D coupled rotator lattice is a notable exception which conserves total momentum while exhibits normal heat conduction behavior. The temperature behavior of the thermal conductivities of 1D coupled rotator lattice had been studied in previous works trying to reveal the underlying physical mechanism for normal heat conduction. However, two different temperature behaviors of thermal conductivities have been claimed for the same coupled rotator lattice. These different temperature behaviors also intrigue the debate whether there is a phase transition of thermal conductivities as the function of temperature. In this work, we will revisit the temperature dependent thermal conductivities for the 1D coupled rotator lattice. We find that the temperature dependence follows a power law behavior which is different with the previously found temperature behaviors. Our results also support the claim that there is no phase transition for 1D coupled rotator lattice. We also give some discussion about the similarity of diffusion behaviors between the 1D coupled rotator lattice and the single kicked rotator also called the Chirikov standard map.

Yunyun Li; Nianbei Li; Baowen Li

2015-01-29T23:59:59.000Z

195

IEEE TRANSACTIONS ON COMPONENTS AND PACKAGING TECHNOLOGIES, VOL. 25, NO. 4, DECEMBER 2002 615 In-Plane Effective Thermal Conductivity of  

E-Print Network [OSTI]

material. Thermal conductivity of second phase material. . . Heat flux. Mesh numbers along. Effective thermal resistance. Thermal diffusivity. Specific surface area. Porosity. Time. Manuscript effect, the effective thermal conductivity of these materials, is relatively small, so that much

Wirtz, Richard A.

196

Thermal management of batteries using a Variable-Conductance Insulation (VCI) enclosure  

SciTech Connect (OSTI)

Proper thermal management is important for optimum performance and durability of most electric-vehicle batteries. For high-temperature cells such as sodium/sulphur, a very efficient and responsive thermal control system is essential. Heat must be removed during exothermic periods and retained when the batteries are not in use. Current thermal management approaches rely on passive insulation enclosures with active cooling loops that penetrate the enclosure. This paper presents the design, analysis, and testing of an enclosure with variable conductance insulation (VCI). VCI uses a hydride with an integral electric resistance heater to expel and retrieve a small amount of hydrogen gas into a vacuum space. By controlling the amount of hydrogen gas, the thermal conductance can be varied by more than 100:1, enabling the cooling loop (cold plate) to be mounted on the enclosure exterior. By not penetrating the battery enclosure, the cooling system is simpler and more reliable. Also, heat can be retained more effectively when desired. For high temperatures, radiation shields within the vacuum space are required. Ceramic spacers are used to maintain separation of the steel enclosure materials against atmospheric loading. Ceramic-to-ceramic thermal contact resistance within the spacer assembly minimizes thermal conductance. Two full-scale (0.8-m {times} 0.9-m {times} 0.3-m) prototypes were designed, built, and tested under high-temperature 200{degrees}-350{degrees}C battery conditions. With an internal temperature of 330{degrees}C (and 20{degrees}C ambient), the measured total-enclosure minimum heat loss was 80 watts (excluding wire pass-through losses). The maximum heat rejection was 4100 watts. The insulation can be switched from minimum to maximum conductance (hydrogen pressure from 2.0 {times} 10{sup -3} to 8 torr) in 3 minutes. Switching from maximum to minimum conductance was longer (16 minutes), but still satisfactory because of the large thermal mass of the battery.

Burch, S.D.; Parish, R.C.; Keyser, M.A.

1995-05-01T23:59:59.000Z

197

High Thermal Conductivity UO2-BeO Nulcear Fuel: Neutronic Performance Assessments and Overview of Fabrication  

E-Print Network [OSTI]

for the continuous (a) and dispersed (b) types [16]. 2.3 Silicon Carbide as a High Conductivity Additive Solomon et al. explored the feasibility of increasing the thermal conductivity of oxide fuels by the addition of a second, higher thermal conductivity solid... methodology used to restrict the CO or SiO gases. All processing, therefore, must take place below this temperature. Because of ! "# Table 2.3. Samples used in the thermal conductivity measurements $%&'()&*! $(+!%,-.&/! 0...

Naramore, Michael J

2010-08-03T23:59:59.000Z

198

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

SciTech Connect (OSTI)

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.

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

2006-06-26T23:59:59.000Z

199

Thermal Conductivity of Thermally-Isolating Polymeric and Composite Structural Support Materials Between 0.3 and 4 K  

E-Print Network [OSTI]

We present measurements of the low-temperature thermal conductivity of a number of polymeric and composite materials from 0.3 to 4 K. The materials measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301, G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and graphite rod. These materials have moderate to high elastic moduli making them useful for thermally-isolating structural supports.

M. C. Runyan; W. C. Jones

2008-06-11T23:59:59.000Z

200

Thermal Conductivity of Thermally-Isolating Polymeric and Composite Structural Support Materials Between 0.3 and 4 K  

E-Print Network [OSTI]

We present measurements of the low-temperature thermal conductivity of a number of polymeric and composite materials from 0.3 to 4 K. The materials measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301, G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and graphite rod. These materials have moderate to high elastic moduli making them useful for thermally-isolating structural supports.

Runyan, M C

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

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

SciTech Connect (OSTI)

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.

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)

2014-10-15T23:59:59.000Z

202

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

SciTech Connect (OSTI)

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.

Toews, W. H.; Hill, R. W. [GWPI and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)] [GWPI and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

2014-04-15T23:59:59.000Z

203

Analysis of the Temporal Evolution of Thermal Conductivity in Alumina-Water Nanofluid  

E-Print Network [OSTI]

be modeled as particles possessing interfacial shells [8] or nanolayers composed of interfacial particles [9] in an effort to explain observed enhancements of fluid thermal conductivity. Fractal models have also been proposed to describe the effect... of nanoparticle-fluid mixture, Int. J. of Heat and Mass Trans. 48 (2005) 2926-2932. [10] B.X. Wang, L.P. Zing, X.F. Peng, A fractal model for predicting the effective thermal conductivity of liquid with suspension of nanoparticles, Int. J. of Heat and Mass...

Fortenberry, Stephen

2009-09-30T23:59:59.000Z

204

Effective thermal conductivity of two-phase functionally graded particulate H. M. Yin, G. H. Paulino,a  

E-Print Network [OSTI]

, a continuous trade-off of fracture toughness and high thermal conductivity of metals is made with ceramic of the ceramic portions of FGMs. The effective thermal properties in the gradation direction are es- sentialEffective thermal conductivity of two-phase functionally graded particulate composites H. M. Yin, G

Paulino, Glaucio H.

205

PHYSICAL REVIEW B 83, 174205 (2011) Testing the minimum thermal conductivity model for amorphous polymers using high pressure  

E-Print Network [OSTI]

, and propagons" to classify the vibrational modes of disordered materials and their contributions to thermal predict the thermal conductivity of most amorphous materials--and many strongly disordered crystals) simulations of polystyrene (PS)7 and proteins.8,9 Pressure tuning of the thermal conductivity enables

Braun, Paul

206

PHYSICAL REVIEW B 83, 094521 (2011) Thermal conductivity in the mixed state of a superconductor at low magnetic fields  

E-Print Network [OSTI]

15 March 2011) We evaluate accurate low-field/low-temperature asymptotics of the thermal conductivityPHYSICAL REVIEW B 83, 094521 (2011) Thermal conductivity in the mixed state of a superconductor conductivity at low fields. DOI: 10.1103/PhysRevB.83.094521 PACS number(s): 74.25.fc, 74.25.Uv I. INTRODUCTION

Alexei, Koshelev

207

MAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS  

E-Print Network [OSTI]

MAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS H.-M. Chang and K The stability conditions that take into accounts the size of superconducting magnets and the refrigeration the refrigeration, causing a rise in the temperature of the magnet winding and leading to burnout. It is shown

Chang, Ho-Myung

208

The self-heating of damp cellulosic materials: I. High thermal conductivity and diffusivity  

Science Journals Connector (OSTI)

......self-heating of damp cellulosic materials: I. High thermal conductivity...stockpiles of cellulosic materials are analysed. The model...distinct bifurcation diagrams. In particular it is...stockpile sizes for materials prone to self-heating...surfaces by breakage on handling. In such circumstances......

R. A. SISSON; A. SWIFT; G. C. WAKE; B. F. GRAY

1992-01-01T23:59:59.000Z

209

Porous yttria-stabilized zirconia ceramics with ultra-low thermal conductivity  

Science Journals Connector (OSTI)

Porous yttria-stabilized zirconia (ZrO2-8 mol% Y2O3, YSZ) ceramics with ultra-low thermal conductivity (as low as 0.06 W/mK) could be fabricated by tert-butyl alcohol...

LiangFa Hu; Chang-An Wang; Yong Huang

2010-06-01T23:59:59.000Z

210

Impacts of Soil and Pipe Thermal Conductivity on Performance of Horizontal Pipe in a Ground-source Heat Pump  

E-Print Network [OSTI]

In this paper the composition and thermal property of soil are discussed. The main factors that impact the soil thermal conductivity and several commonly-used pipe materials are studied. A model of heat exchanger with horizontal pipes of ground...

Song, Y.; Yao, Y.; Na, W.

2006-01-01T23:59:59.000Z

211

Thermal Conductivity of SiC/Si Composites – Porting PNNL EMTA Code for Fusion Analyses  

SciTech Connect (OSTI)

An existing modeling method, the EMTA (Eshelby-Mori-Tanaka approach) modeling approach [1], is applied to the study of SiC/SiC 2D woven composites for fusion reactor applications for the first time, to the best of our knowledge, with excellent results. We compare EMTA model results to existing thermal conductivity data for these materials and suggest that in the future this approach can be beneficial by providing us with tools to further optimize these composite materials for fusion energy applications since the EMTA method and code can address both thermal and mechanical properties with the same framework.

Henager, Charles H.; Nguyen, Ba Nghiep

2013-04-19T23:59:59.000Z

212

COLD FRONTS AND GAS SLOSHING IN GALAXY CLUSTERS WITH ANISOTROPIC THERMAL CONDUCTION  

SciTech Connect (OSTI)

Cold fronts in cluster cool cores should be erased on short timescales by thermal conduction, unless protected by magnetic fields that are 'draped' parallel to the front surfaces, suppressing conduction perpendicular to the sloshing fronts. We present a series of MHD simulations of cold front formation in the core of a galaxy cluster with anisotropic thermal conduction, exploring a parameter space of conduction strengths parallel and perpendicular to the field lines. Including conduction has a strong effect on the temperature distribution of the core and the appearance of the cold fronts. Though magnetic field lines are draping parallel to the front surfaces, preventing conduction directly across them, the temperature jumps across the fronts are nevertheless reduced. The geometry of the field is such that the cold gas below the front surfaces can be connected to hotter regions outside via field lines along directions perpendicular to the plane of the sloshing motions and along sections of the front that are not perfectly draped. This results in the heating of this gas below the front on a timescale of a Gyr, but the sharpness of the density and temperature jumps may nevertheless be preserved. By modifying the gas density distribution below the front, conduction may indirectly aid in suppressing Kelvin-Helmholtz instabilities. If conduction along the field lines is unsuppressed, we find that the characteristic sharp jumps seen in Chandra observations of cold front clusters do not form. Therefore, the presence of cold fronts in hot clusters is in contradiction with our simulations with full Spitzer conduction. This suggests that the presence of cold fronts in hot clusters could be used to place upper limits on conduction in the bulk of the intracluster medium. Finally, the combination of sloshing and anisotropic thermal conduction can result in a larger flux of heat to the core than either process in isolation. While still not sufficient to prevent a cooling catastrophe in the very central (r {approx} 5 kpc) regions of the cool core (where something else is required, such as active galactic nucleus feedback), it reduces significantly the mass of gas that experiences a cooling catastrophe outside those small radii.

ZuHone, J. A.; Markevitch, M. [Astrophysics Science Division, Laboratory for High Energy Astrophysics, Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [Astrophysics Science Division, Laboratory for High Energy Astrophysics, Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ruszkowski, M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Lee, D. [The Flash Center for Computational Science, The University of Chicago, 5747 S. Ellis, Chicago, IL 60637 (United States)] [The Flash Center for Computational Science, The University of Chicago, 5747 S. Ellis, Chicago, IL 60637 (United States)

2013-01-10T23:59:59.000Z

213

Theory of interparticle correlations in dense, high-temperature plasmas. V. Electric and thermal conductivities  

Science Journals Connector (OSTI)

On the basis of the quantum-statistical formulation of electronic transport, we calculate the electric and thermal conductivities of plasmas in a wide range of densities and temperatures where it is essential to take into account the varied degrees of electron degeneracy and local-field corrections describing the strong Coulomb-coupling effects. The physical implications of the results are investigated through comparison with other theories and experiments. For utility in the practical applications, we derive the analytic formulas parametrizing the computed results accurately for the generalized Coulomb logarithms appearing in those conductivities.

Setsuo Ichimaru and Shigenori Tanaka

1985-09-01T23:59:59.000Z

214

Unglazed transpired solar collector having a low thermal-conductance absorber  

DOE Patents [OSTI]

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.

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

1997-12-02T23:59:59.000Z

215

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

SciTech Connect (OSTI)

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), UV–vis spectroscopy, inductively coupled plasma (ICP) and N{sub 2} adsorption–desorption 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.

Tadjarodi, Azadeh, E-mail: tajarodi@iust.ac.ir [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Zabihi, Fatemeh [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Chemistry and Nanotechnology Laboratory, National Center for Laser Science and Technology, Tehran (Iran, Islamic Republic of)

2013-10-15T23:59:59.000Z

216

Unglazed transpired solar collector having a low thermal-conductance absorber  

DOE Patents [OSTI]

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.

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

1997-01-01T23:59:59.000Z

217

THE JOURNAL OF CHEMICAL PHYSICS 140, 114502 (2014) Thermal conductivity of simple liquids: Origin of temperature and packing  

E-Print Network [OSTI]

. For example, in concen- trating solar power plants1 or in prospective Generation IV nuclear reactors,2THE JOURNAL OF CHEMICAL PHYSICS 140, 114502 (2014) Thermal conductivity of simple liquids: Origin dependence of T1/4 3/2 in the thermal conductivity of the simple Lennard-Jones (LJ) liquid is explored

Boyer, Edmond

218

Oxidation of Metals, Vol. 61, Nos. 3/4, April 2004 ( 2004) Thermal Conductivity, Phase Stability, and Oxidation  

E-Print Network [OSTI]

, and Oxidation Resistance of Y3Al5O12 (YAG)/Y2O3­ZrO2 (YSZ) Thermal-Barrier Coatings Y. J. Su, R. W. Trice,# K oxidation resistance while maintaining low thermal conductivity and good phase stability. Padture) is proposed. The objective of this work is to quantify the effect of YAG on thermal resistance, long

Trice, Rodney W.

219

Phonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu, and Alexander A. Balandina  

E-Print Network [OSTI]

or polycrystalline materials in terms of thermal transport. © 2005 American Institute of Physics. DOI: 10 strongly depends on interface conditions, is considered as a major thermal resistive mecha- nismPhonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu

220

Thermal conductivity of diamond-loaded glues for the ATLAS particle physics detector  

E-Print Network [OSTI]

The ATLAS experiment is one of two large general-purpose particle detectors at the Large Hadron Collider (LHC) at the CERN laboratory in Geneva, Switzerland. ATLAS has been collecting data from the collisions of protons since December 2009, in order to investigate the conditions that existed during the early Universe and the origins of mass, and other topics in fundamental particle physics. The innermost layers of the ATLAS detector will be exposed to the most radiation over the first few years of operation at the LHC. In particular, the layer closest to the beam pipe, the B-layer, will degrade over time due to the added radiation. To compensate for its degradation, it will be replaced with an Insertable B-Layer (IBL) around 2016. The design of and R&D for the IBL is ongoing, as the hope is to use the most current technologies in the building of this new sub-detector layer. One topic of interest is the use of more thermally conductive glues in the construction of the IBL, in order to facilitate in the dissipation of heat from the detector. In this paper the measurement and use of highly thermally conductive glues, in particular those that are diamond-loaded, will be discussed. The modified transient plane source technique for thermal conductivity is applied in characterizing the glues across a wide temperature range.

E. A. Ouellette; A. Harris

2010-08-04T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Electron thermal conduction as a possible mechanism to make the inner heliosheath thnner  

E-Print Network [OSTI]

We show that the electron thermal conductivity may strongly affect the heliosheath plasma flow and the global pattern of the solar wind (SW) interaction with the local interstellar medium (LISM). In particular, it leads to strong reduction of the inner heliosheath thickness that makes possible to explain (qualitatively) why Voyager 1 (V1) has crossed the heliopause at 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 V1 direction compared to the adiabatic case with gamma = 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 become equal to 32 AU.

Izmodenov, V V; Ruderman, M S

2014-01-01T23:59:59.000Z

222

Determination of temperature-dependent heat conductivity and thermal diffusivity of waste glass melter feed  

SciTech Connect (OSTI)

The cold cap is a layer of reacting glass batch floating on the surface of melt in an all-electric continuous glass melter. The heat needed for the conversion of the melter feed to molten glass must be transferred to and through the cold cap. Since the heat flux into the cold cap determines the rate of melting, the heat conductivity is a key property of the reacting feed. We designed an experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples that monitors the evolution of the temperature field while the crucible is heated at a constant rate. Then we used two methods to calculate the heat conductivity and thermal diffusivity of the reacting feed: the approximation of the temperature field by polynomial functions and the finite-volume method coupled with least-squares analysis. Up to 680°C, the heat conductivity of the reacting melter feed was represented by a linear function of temperature.

Pokorny, Richard; Rice, Jarrett A.; Schweiger, Michael J.; Hrma, Pavel R.

2013-06-01T23:59:59.000Z

223

Measurement of temperature-dependent thermal conductivity and viscosity of TiO{sub 2}-water nanofluids  

SciTech Connect (OSTI)

Nanofluid is an innovative heat transfer fluid with superior potential for enhancing the heat transfer performance of conventional fluids. Many attempts have been made to investigate its thermal conductivity and viscosity, which are important thermophysical properties. No definitive agreements have emerged, however, about these properties. This article reports the thermal conductivity and dynamic viscosity of nanofluids experimentally. TiO{sub 2} nanoparticles dispersed in water with volume concentration of 0.2-2 vol.% are used in the present study. A transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids whereas the Bohlin rotational rheometer (Malvern Instrument) is used to measure the viscosity of nanofluids. The data are collected for temperatures ranging from 15 C to 35 C. The results show that the measured viscosity and thermal conductivity of nanofluids increased as the particle concentrations increased and are higher than the values of the base liquids. Furthermore, thermal conductivity of nanofluids increased with increasing nanofluid temperatures and, conversely, the viscosity of nanofluids decreased with increasing temperature of nanofluids. Moreover, the measured thermal conductivity and viscosity of nanofluids are quite different from the predicted values from the existing correlations and the data reported by other researchers. Finally, new thermophysical correlations are proposed for predicting the thermal conductivity and viscosity of nanofluids. (author)

Duangthongsuk, Weerapun; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, 126 Bangmod, Bangkok 10140 (Thailand)

2009-04-15T23:59:59.000Z

224

First-Principles Determination of Ultrahigh Thermal Conductivity of Boron Arsenide: A Competitor for Diamond?  

Science Journals Connector (OSTI)

We have calculated the thermal conductivities (?) of cubic III-V boron compounds using a predictive first principles approach. Boron arsenide is found to have a remarkable room temperature ? over 2000??W?m-1?K-1; this is comparable to those in diamond and graphite, which are the highest bulk values known. We trace this behavior in boron arsenide to an interplay of certain basic vibrational properties that lie outside of the conventional guidelines in searching for high ? materials, and to relatively weak phonon-isotope scattering. We also find that cubic boron nitride and boron antimonide will have high ? with isotopic purification. This work provides new insight into the nature of thermal transport at a quantitative level and predicts a new ultrahigh ? material of potential interest for passive cooling applications.

L. Lindsay; D. A. Broido; T. L. Reinecke

2013-07-08T23:59:59.000Z

225

Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction  

SciTech Connect (OSTI)

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.

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)

2014-02-24T23:59:59.000Z

226

Temperature Dependent Thermal Conductivity of Si/SiC Amorphous Multilayer Films  

SciTech Connect (OSTI)

The cross-plane thermal conductivity of 22 nm period Si/SiC amorphous multilayer films deposited by magnetron sputtering and measured using a differential 3{omega} method was found to decrease from 2.0 W/mK at 300 K to 1.1 W/mK at 80 K. Structural disorder in each of the constituent layers of the amorphous multilayer films was confirmed by high resolution transmission electron microscopy. Estimations of the relative contributions of interface and intrinsic layer thermal resistance based on microscopic phonon transport models indicate that mean free path reductions induced by the structural disorder within the multilayer films are responsible for the observed experimental trends.

Mazumder, M.; Solovyov, S.; Borca-Tasciuc, T.; Teehan, S.C.; Stinzianni, E.; Efstathiadis, H.

2010-03-01T23:59:59.000Z

227

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

SciTech Connect (OSTI)

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 2800°C in vacuum and about 750°C 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 UO2–CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (5–15 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.

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

2014-03-10T23:59:59.000Z

228

Nanoscale Graphene Disk: A Natural Functionally Graded Material --The Thermal Conductivity of Nanoscale Graphene Disk by Molecular Dynamics Simulation  

E-Print Network [OSTI]

In this letter, we investigate numerically (by non-equilibrium molecular dynamics) and analytically the thermal conductivity of nanoscale graphene disks (NGDs), and discussed the possibility to realize FGM with only one material, NGDs. We found that the NGD has a graded thermal conductivity and can be used as FGM in a large temperature range. Moreover, we show the dependent of NGDs' thermal conductivity on radius and temperature. Our study may inspire experimentalists to develop NGD based FGMs and help heat removal of hot spots on chips by graphene.

Yang, Nuo; Ma, Dengke; Lu, Tingyu; Li, Baowen

2014-01-01T23:59:59.000Z

229

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

DOE Patents [OSTI]

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.

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

2010-07-27T23:59:59.000Z

230

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

SciTech Connect (OSTI)

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.

Cable, William; Romanovsky, Vladimir

2014-03-31T23:59:59.000Z

231

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

SciTech Connect (OSTI)

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.

Chow, Philippe K.; O'Brien, Peter; Ramanath, Ganpati [Rensselaer Polytechnic Institute, Department of Materials Science and Engineering, Troy, New York 12180 (United States)] [Rensselaer Polytechnic Institute, Department of Materials Science and Engineering, Troy, New York 12180 (United States); Cardona Quintero, Y.; Ramprasad, R. [Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269 (United States)] [Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269 (United States); Hubert Mutin, P. [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Universite Montpellier 2, CC 1701, Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France)] [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, Universite Montpellier 2, CC 1701, Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France); Lane, Michael [Chemistry Department, Emory and Henry College, Emory, Virginia 24327 (United States)] [Chemistry Department, Emory and Henry College, Emory, Virginia 24327 (United States)

2013-05-20T23:59:59.000Z

232

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

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

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.

Cable, William; Romanovsky, Vladimir

233

Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications  

E-Print Network [OSTI]

Proceedings on thermal energy storage and energy conversion;polymer microcomposites for thermal energy storage. SAE SocLow temperature thermal energy storage: a state of the art

Roshandell, Melina

2013-01-01T23:59:59.000Z

234

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

DOE Patents [OSTI]

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.

Haney, Steven J. (Tracy, CA); Stulen, Richard H. (Livermore, CA); Toly, Norman F. (Livermore, CA)

1985-01-01T23:59:59.000Z

235

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

DOE Patents [OSTI]

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.

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

1983-05-03T23:59:59.000Z

236

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

SciTech Connect (OSTI)

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.

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

2014-02-21T23:59:59.000Z

237

Transport properties, specific heat and thermal conductivity of GaN nanocrystalline ceramic  

SciTech Connect (OSTI)

The structural and transport properties (resistivity, thermopower and Hall effect), specific heat and thermal conductivity have been measured for GaN nanocrystalline ceramic prepared by hot pressing. It was found that the temperature dependence of resistivity in temperature range 10-300 K shows the very low activation energy, which is ascribed to the shallow donor doping originating in amorphous phase of sample. The major charge carriers are electrons, what is indicated by negative sign of Hall constant and Seebeck coefficient. The thermopower attains large values (-58 {mu}V/K at 300 K) and was characterized by linear temperature dependence which suggests the diffusion as a major contribution to Seebeck effect. The high electron concentration of 1.3x10{sup 19} cm{sup -3} and high electronic specific heat coefficient determined to be 2.4 mJ/molK{sup 2} allow to conclude that GaN ceramic demonstrates the semimetallic-like behavior accompanied by very small mobility of electrons ({approx}0.1 cm{sup 2}/V s) which is responsible for its high resistivity. A low heat conductivity of GaN ceramics is associated with partial amorphous phase of GaN grains due to high pressure sintering. - Graphical Abstract: Thermal resistivity and thermopower measurements indicates the high phonon scattering and lack of phonon-drag contribution to thermopower in GaN nanoceramics pressed under 4 GPa at 800 {sup o}C.

Sulkowski, Czeslaw [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); ChuchmaLa, Andrzej, E-mail: andrzej.chuchmala@pwr.wroc.p [Wroclaw University of Technology, Institute of Electrical Engineering Fundamentals (I7), Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Zaleski, Andrzej J.; Matusiak, Marcin; Mucha, Jan; GLuchowski, PaweL; Strek, WiesLaw [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)

2010-10-15T23:59:59.000Z

238

A Gas Chromatography–Thermal Conductivity Detection Method for Helium Detection in Postmortem Blood and Tissue Specimens  

Science Journals Connector (OSTI)

......victim's head, although some internet sources recommend use of...for volatiles and drugs of abuse. The cause of death was...Discussion of the Influence of the Internet. Am. J. Forensic Med...Suicide Thermal Conductivity Young Adult...

Jason E. Schaff; Roman P. Karas; Laureen Marinetti

2012-03-01T23:59:59.000Z

239

PHYSICAL REVIEW B 84, 054203 (2011) Electrical and thermal conductivity of liquid sodium from first-principles calculations  

E-Print Network [OSTI]

pipes in high-temperature solar-energy power plants, thanks to its large thermal conductivity, which Laboratories, Albuquerque, New Mexico 87185, USA (Received 23 May 2011; published 4 August 2011) We report

Alfè, Dario

240

Thermal conductivity of the insulation system of the stator winding of a high-power turbogenerator with air cooling  

Science Journals Connector (OSTI)

Values of the thermal-conductivity coefficient of specimens of the frame insulation manufactured from pre- and unimpregnated, mica-containing tapes are determined. It is established that the tape structure, te...

A. Sh. Azizov; A. M. Andreev; A. M. Kostel’ov…

2009-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Evaluation of the Thermal Performance for a Wire Mesh/Hollow Glass Microsphere Composite Structure as a Conduction Barrier  

E-Print Network [OSTI]

An experimental investigation exploring the use of wire mesh/hollow glass microsphere combination for use as thermal insulation was conducted with the aim to conclude whether or not it represents a superior insulation technology to those...

Mckenna, Sean

2010-01-15T23:59:59.000Z

242

An experimental investigation of thermal contact conductance across carbon fiber/epoxy resin composites as a function of interface pressure  

E-Print Network [OSTI]

AN EXPERIMENTAL INVESTIGATION OF THERMAL CONTACT CONDUCTANCE ACROSS CARBON FIBER/EPOXY RESIN COMPOSITES AS A FUNCTION OF INTERFACE PRESSURE A Thesis by MICHAEL EVERETT RHOADES Submitted to the Office of Graduate Studies of Texas A...&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1989 Major Subject: Mechanical Engineering AN EXPERIMENTAL INVESTIGATION OF THERMAL CONTACT CONDUCTANCE ACROSS CARBON FIBER/EPOXY RESIN COMPOSITES AS A...

Rhoades, Michael Everett

1989-01-01T23:59:59.000Z

243

Polymer Composites with Enhanced Thermal Conductivity: This research is funded by Honeywell Corporation and the Florida High Tech Corridor.  

E-Print Network [OSTI]

Polymer Composites with Enhanced Thermal Conductivity: This research is funded by Honeywell/mK (50). Earlier work with Honeywell focused on the development of boron nitride/epoxy composites. We. Encouraging results prompted Honeywell, Inc to file a patent application with us (53). #12;The target thermal

Harmon, Julie P.

244

Thermally conductive cementitious grouts for geothermal heat pumps. Progress report FY 1998  

SciTech Connect (OSTI)

Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98. The developed thermally conductive grout consists of cement, water, a particular grade of silica sand, superplasticizer and a small amount of bentonite. While the primary function of the grout is to facilitate heat transfer between the U-loop and surrounding formation, it is also essential that the grout act as an effective borehole sealant. Two types of permeability (hydraulic conductivity) tests was conducted to evaluate the sealing performance of the cement-sand grout. Additional properties of the proposed grout that were investigated include bleeding, shrinkage, bond strength, freeze-thaw durability, compressive, flexural and tensile strengths, elastic modulus, Poisson`s ratio and ultrasonic pulse velocity.

Allan, M.L.; Philippacopoulos, A.J.

1998-11-01T23:59:59.000Z

245

Determination of heat conductivity and thermal diffusivity of waste glass melter feed: Extension to high temperatures  

SciTech Connect (OSTI)

The heat conductivity ({lambda}) and the thermal diffusivity (a) of reacting glass batch, or melter feed, control the heat flux into and within the cold cap, a layer of reacting material floating on the pool of molten glass in an all-electric continuous waste glass melter. After previously estimating {lambda} of melter feed at temperatures up to 680 deg C, we focus in this work on the {lambda}(T) function at T > 680 deg C, at which the feed material becomes foamy. We used a customized experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples, which monitored the evolution of the temperature field while the crucible with feed was heated at a constant rate from room temperature up to 1100°C. Approximating measured temperature profiles by polynomial functions, we used the heat transfer equation to estimate the {lambda}(T) approximation function, which we subsequently optimized using the finite-volume method combined with least-squares analysis. The heat conductivity increased as the temperature increased until the feed began to expand into foam, at which point the conductivity dropped. It began to increase again as the foam turned into a bubble-free glass melt. We discuss the implications of this behavior for the mathematical modeling of the cold cap.

Rice, Jarrett A.; Pokorny, Richard; Schweiger, Michael J.; Hrma, Pavel R.

2014-05-12T23:59:59.000Z

246

Measurement of the Anisotropic Thermal Conductivity of Molybdenum Disulfide Single Crystal by the Time-resolved Magneto-optic Kerr Effect  

E-Print Network [OSTI]

with perpendicular magnetization serves as the heater and thermometer in the experiment. The low thermal conductivity for determining the thermal conductivity of materials but the sensitivity of TDTR to the lateral or in-plane thermal conductivity of a sample is low when conventional choices are made for laser spot sizes, #12

Cahill, David G.

247

Thermal conductance of graphene and dimerite Jin-Wu Jiang,1 Jian-Sheng Wang,1 and Baowen Li1,2,*  

E-Print Network [OSTI]

Thermal conductance of graphene and dimerite Jin-Wu Jiang,1 Jian-Sheng Wang,1 and Baowen Li1,2,* 1; published 20 May 2009 We investigate the phonon thermal conductance of graphene regarding the graphene sheet as the large-width limit of graphene strips in the ballistic limit. We find that the thermal conductance

Li, Baowen

248

Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber  

Science Journals Connector (OSTI)

A novel 3?thermal conductivitymeasurement technique called metal-coated 3? is introduced for use with liquids gases powders and aerogels. This technique employs a micron-scale metal-coated glass fiber as a heater/thermometer that is suspended within the sample. Metal-coated 3? exceeds alternate 3? based fluid sensing techniques in a number of key metrics enabling rapid measurements of small samples of materials with very low thermal effusivity (gases) using smaller temperature oscillations with lower parasitic conduction losses. Its advantages relative to existing fluid measurement techniques including transient hot-wire steady-state methods and solid-wire 3? are discussed. A generalized n-layer concentric cylindrical periodic heating solution that accounts for thermal boundary resistance is presented. Improved sensitivity to boundary conductance is recognized through this model. Metal-coated 3? was successfully validated through a benchmark study of gases and liquids spanning two-orders of magnitude in thermal conductivity.

Scott N. Schiffres; Jonathan A. Malen

2011-01-01T23:59:59.000Z

249

Modeling properties of chromospheric evaporation driven by thermal conduction fronts from reconnection shocks  

E-Print Network [OSTI]

Magnetic reconnection in the corona results in contracting flare loops, releasing energy into plasma heating and shocks. The hydrodynamic shocks so produced drive thermal conduction fronts (TCFs) which transport energy into the chromosphere and drive upflows (evaporation) and downflows (condensation) in the cooler, denser footpoint plasma. Observations have revealed that certain properties of the transition point between evaporation and condensation (the "flow reversal point" or FRP), such as temperature and velocity-temperature derivative at the FRP, vary between different flares. These properties may provide a diagnostic tool to determine parameters of the coronal energy release mechanism and the loop atmosphere. In this study, we develop a 1-D hydrodynamical flare loop model with a simplified three-region atmosphere (chromosphere/transition region/corona), with TCFs initiated by shocks introduced in the corona. We investigate the effect of two different flare loop parameters (post-shock temperature and tra...

Brannon, Sean

2014-01-01T23:59:59.000Z

250

Thermal conductivity and phonon linewidths of monolayer MoS{sub 2} from first principles  

SciTech Connect (OSTI)

Using ab initio calculations, we have investigated the phonon linewidths and the thermal conductivity (?) of monolayer MoS{sub 2}. ? for a typical sample size of 1??m is 83 W/m K at room temperature in the completely rough edge limit, suggesting ? is not a limiting factor for the electronic application of monolayer MoS{sub 2}. ? can be further increased by 30% in 10??m sized samples. Due to strong anharmonicity, isotope enhancement of room temperature ? is only 10% for 1??m sized samples. However, linewidths can be significantly reduced, for instance, for Raman active modes A{sub 1g} and E{sub 2g}{sup 1}, in isotopically pure samples.

Li, Wu, E-mail: wu.li.phys2011@gmail.com; Carrete, J.; Mingo, Natalio, E-mail: natalio.mingo@cea.fr [CEA-Grenoble, 17 Rue des Martyrs, Grenoble 38000 (France)] [CEA-Grenoble, 17 Rue des Martyrs, Grenoble 38000 (France)

2013-12-16T23:59:59.000Z

251

Microstructure and thermal conductivity of surfactant-free NiO nanostructures  

SciTech Connect (OSTI)

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.

Sahoo, Pranati [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Misra, Dinesh K. [The Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Salvador, Jim [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, Warren, MI 48090 (United States); Makongo, Julien P.A. [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Chaubey, Girija S. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Takas, Nathan J. [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Wiley, John B. [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States)

2012-06-15T23:59:59.000Z

252

Microsegregation effects on the thermal conductivity of silicon-germanium alloys  

SciTech Connect (OSTI)

A silicon-germanium (SiGe) alloy is a promising candidate for thermoelectric materials; while it shows a significantly reduced thermal conductivity (?) as compared to pure Si and Ge, the ? values obtained from previous experiments and computations tend to be widely scattered. We present here a computational analysis of thermal transport in SiGe, particularly the effects of the local segregation (microsegregation) of alloying elements. Our nonequilibrium molecular dynamics simulations confirm the strong dependence of ? on the Si:Ge ratio and the occurrence of the minimum ? around Si{sub 0.8}Ge{sub 0.2}, consistent with existing experimental observations. Moreover, our study clearly demonstrates that the ? of Si{sub 0.8}Ge{sub 0.2} increases substantially and monotonically as Ge atoms undergo segregation; that is, the magnitude of alloy scattering is found to be sensitive to homogeneity in the distribution of alloying elements. Nonequilibrium Green's function analysis also shows that such microsegregation enhances phonon transmission due to the reduced number of scattering centers. The findings highlight that distribution homogeneity, along with composition, can be a critical factor in determining the ? of SiGe alloys.

Lee, Yongjin; Hwang, Gyeong S., E-mail: gshwang@che.utexas.edu [Department of Chemical Engineering, University of Texas, Austin, Texas 78712 (United States)

2013-11-07T23:59:59.000Z

253

Determination of thermal conductivity and formation temperature from cooling history of friction-heated probes  

Science Journals Connector (OSTI)

......dissipation at the rising cost of ship operational time...penetrations for measurements of geothermal gradients at closely...paves the way at no extra cost for the determination...imposing heat flow as an energy constraint in transient...typical measurement of geothermal gradient in the ocean......

Tien-Chang Lee; A. D. Duchkov; S. G. Morozov

2003-02-01T23:59:59.000Z

254

Thermal conduction by dark matter with velocity and momentum-dependent cross-sections  

E-Print Network [OSTI]

We use the formalism of Gould and Raffelt to compute the dimensionless thermal conduction coefficients for scattering of dark matter particles with standard model nucleons via cross-sections that depend on the relative velocity or momentum exchanged between particles. Motivated by models invoked to reconcile various recent results in direct detection, we explicitly compute the conduction coefficients $\\alpha$ and $\\kappa$ for cross-sections that go as $v_{\\rm rel}^2$, $v_{\\rm rel}^4$, $v_{\\rm rel}^{-2}$, $q^2$, $q^4$ and $q^{-2}$, where $v_{\\rm rel}$ is the relative DM-nucleus velocity and $q$ is the momentum transferred in the collision. We find that a $v_{\\rm rel}^{-2}$ dependence can significantly enhance energy transport from the inner solar core to the outer core. The same can true for any $q$-dependent coupling, if the dark matter mass lies within some specific range for each coupling. This effect can complement direct searches for dark matter; combining these results with state-of-the-art Solar simulations should greatly increase sensitivity to certain DM models. It also seems possible that the so-called Solar Abundance Problem could be resolved by enhanced energy transport in the solar core due to such velocity- or momentum-dependent scatterings.

Aaron C. Vincent; Pat Scott

2013-11-08T23:59:59.000Z

255

Effects of temperature and disorder on thermal boundary conductance at solidsolid interfaces: Nonequilibrium  

E-Print Network [OSTI]

with the constituent materials. The inter- face thermal resistance, often referred to as thermal boundary resistance between two different materials when a heat flux is applied. The inverse of thermal boundary resistance mismatched interfaces. Ã? 2007 Elsevier Ltd. All rights reserved. Keywords: Thermal boundary resistance

Zhigilei, Leonid V.

256

Ultra-Low Thermal Conductivity in W/Al2O3 Nanolaminates  

E-Print Network [OSTI]

conversion (3). Conversely, the thermal resistance of interfaces degrades the performance of materials dissimilar materials may provide a route for the production of thermal barriers with ultra-low thermal and improve the performance of thermal bar- riers (2) and of materials used in thermoelec- tric energy

George, Steven M.

257

Thermal conductivity of the electrode gap of a thermionic converter, filled with inert gases, at low pressures  

SciTech Connect (OSTI)

Experimental data is presented on the thermal conductivity of the electrode gap of a thermionic converter filled with He, Ar, and Xe in the pressure range 40--550 Pa. The need to account for the coefficients of thermal accommodation of the emitter-inert-gas-collector system in this range is shown. The accommodation coefficients for different temperature regimes are measured and expressions are obtained to calculate the heat flux transported by the inert gases in the electrode gap.

Modin, V.A.; Nikolaev, Y.V.

1985-11-01T23:59:59.000Z

258

Quantitative analysis of damage in an octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazonic-based composite explosive subjected to a linear thermal gradient  

Science Journals Connector (OSTI)

The microstructure within a slowly heated consolidated explosive will be influenced by both physical changes and chemical reactions prior to thermal ignition. Thermal expansion exothermic decomposition endothermic phase change and increased binder viscosity play significant roles in the cook-off to detonation. To further explore the details of this intricate cook-off process we have conducted a series of experiments in which a carefully controlled temperature gradient has been applied along a cylinder of PBX 9501 [94.9/2.5/2.5/0.1-wt % octahydro-1 3 5 7-tetranitro-1 3 5 7-tetrazocine (HMX)/Estane 5703/a eutectic mixture of bis(2 2 dinitropropyl) acetal and bis(2 2-dinitropropyl) formal [abbreviated BDNPA-F]/Irganox] and maintained for a specified amount of time. After heating and subsequent cooling of the PBX 9501 the sample morphology has been probed with polarized light microscopy and small-angle x-ray scattering. Using these techniques we have quantitatively characterized the particle morphology porosity and chemical state of the explosive as a function of position and therefore thermal treatment. Results of the analyses clearly show that thermal damage in PBX 9501 can be classified into two separate temperature regimes—an initial low-temperature regime ( 155 – 174 ° C ) dominated by the endothermic ? - ? crystalline phase change thermal expansion and Ostwald ripening and a high-temperature regime ( 175 – 210 ° C ) dominated by exothermic chemical decomposition. The results further show the complex interplay between the evolving sample morphology and the chemical reactions leading to a potential thermal self-ignition in the explosive.

Paul D. Peterson; Joseph T. Mang; Blaine W. Asay

2005-01-01T23:59:59.000Z

259

Quantitative analysis of damage in an octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazonic-based composite explosive subjected to a linear thermal gradient  

SciTech Connect (OSTI)

The microstructure within a slowly heated, consolidated explosive will be influenced by both physical changes and chemical reactions prior to thermal ignition. Thermal expansion, exothermic decomposition, endothermic phase change, and increased binder viscosity play significant roles in the cook-off to detonation. To further explore the details of this intricate cook-off process, we have conducted a series of experiments in which a carefully controlled temperature gradient has been applied along a cylinder of PBX 9501 [94.9/2.5/2.5/0.1-wt % octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)/Estane 5703/a eutectic mixture of bis(2,2 dinitropropyl) acetal and bis(2,2-dinitropropyl) formal [abbreviated BDNPA-F]/Irganox] and maintained for a specified amount of time. After heating and subsequent cooling of the PBX 9501, the sample morphology has been probed with polarized light microscopy and small-angle x-ray scattering. Using these techniques we have quantitatively characterized the particle morphology, porosity, and chemical state of the explosive as a function of position, and therefore thermal treatment. Results of the analyses clearly show that thermal damage in PBX 9501 can be classified into two separate temperature regimes--an initial low-temperature regime (155-174 deg. C) dominated by the endothermic {beta}-{delta} crystalline phase change, thermal expansion, and Ostwald ripening, and a high-temperature regime (175-210 deg. C) dominated by exothermic chemical decomposition. The results further show the complex interplay between the evolving sample morphology and the chemical reactions leading to a potential thermal self-ignition in the explosive.

Peterson, Paul D.; Mang, Joseph T.; Asay, Blaine W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2005-05-01T23:59:59.000Z

260

Rotating Solar Jets in Simulations of Flux Emergence with Thermal Conduction  

E-Print Network [OSTI]

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 Hinode/XRT 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 and m...

Fang, Fang; McIntosh, Scott W

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

EXPERIMENTAL MEASUREMENTS OF THE INTERFACE THERMAL CONDUCTANCE OF A LITHIUM METATITANATE PEBBLE BED  

E-Print Network [OSTI]

, CA 90095 aliabousena@engineering.ucla.edu The thermal properties of the lithium ceramics pebble beds will help to create a reliable database of the thermal properties of the lithium ceramics pebble beds. I heat is transferred from the hot lithium ceramic pebble beds to the coolant. The thermal properties

Abdou, Mohamed

262

Measurement of the thermal conductance of the graphene/SiO2 interface Kin Fai Mak, Chun Hung Lui, and Tony F. Heinz  

E-Print Network [OSTI]

, 043112 (2012) Opposite ReD-dependencies of nanofluid (Al2O3) thermal conductivities between heating and cooling modes Appl. Phys. Lett. 101, 083111 (2012) Thermal transport in graphene supported on copper J of thermal transport in this material system2­4 is currently less advanced. The thermal transport properties

Heinz, Tony F.

263

The divergence of neighboring magnetic field lines and fast-particle diffusion in strong magnetohydrodynamic turbulence, with application to thermal conduction in galaxy clusters  

E-Print Network [OSTI]

We investigate field-line separation in strong MHD turbulence using direct numerical simulations. We find that in the static-magnetic-field approximation the thermal conductivity in galaxy clusters is reduced by a factor of about 50 relative to the Spitzer thermal conductivity of a non-magnetized plasma. This value is too small for heat conduction to balance radiative cooling in clusters.

Jason L. Maron; Benjamin D. G. Chandran; Eric G. Blackman

2003-03-11T23:59:59.000Z

264

Experimental and analytical analyses of the thermal conductivities and high-temperature characteristics of silica aerogels based on microstructures  

Science Journals Connector (OSTI)

An analytical heat transfer model based on scanning electron microscopy, Brunauer–Emmett–Teller and pycnometry measurements and a 3D random diffusion-limited cluster–cluster aggregation structure is proposed to calculate the temperature-dependent microstructural parameters and thermal conductivities of silica aerogels. This model is a pure prediction model, which does not need experimentally fitted empirical parameters and only needs four measured structural parameters as input parameters. This model can provide high-temperature microstructural and thermophysical properties as well as theoretical guidelines for material designs with optimum parameters. The results show that three stages occur during the thermal evolution processes of the aerogel structure with increasing temperature from 300 to 1500 K. The current analytical model is fully validated by experimental data. The constant structure assumptions used in previous heat transfer models are found to cause significant errors at higher temperatures as the temperature-dependent structure deformation significantly increases the aerogel thermal conductivity. The conductive and total thermal conductivities of silica aerogels after high-temperature heat treatments are much larger than those with no heat treatment.

Jun-Jie Zhao; Yuan-Yuan Duan; Xiao-Dong Wang; Bu-Xuan Wang

2013-01-01T23:59:59.000Z

265

Microstructural characterization and microstructural effects on the thermal conductivity of AlN(Y2O3) ceramics  

E-Print Network [OSTI]

Microstructural characterization and microstructural effects on the thermal conductivity of AlN(Y2O3) ceramics Ying-Da Yu a , Aase Marie Hundere b , Ragnvald Høier a , Rafal E. Dunin-Borkowski c aluminum nitride (AlN) ceramic materials with Y2O3 as a sintering additive have been sintered at 1880 C

Dunin-Borkowski, Rafal E.

266

E. In Situ Polymerization of Cyclic Butylene Terephthalate(CBT) Oligomers with Conductive fillers for Thermal Management  

E-Print Network [OSTI]

copolymers with Thermal conductivity Composites This research is funded by Honeywell Corporation and the Florida High Tech Corridor. NOTE: Honeywell and Julie Harmon have signed an agreement with Cyclics Corp; these materials exhibit an intrinsic fiber TC as high as 913 W/mK (51). Earlier work with Honeywell focused

Harmon, Julie P.

267

Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications  

E-Print Network [OSTI]

Thermal energy storage for sustainable energy consumption –Sustainable Energy, Cambridge University Press, 65- Dermott A.M, Frysinger G.R, Storage

Roshandell, Melina

2013-01-01T23:59:59.000Z

268

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

SciTech Connect (OSTI)

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 5×1016 He2+/cm2 at low-temperature (< 200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 µm 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 µm) in the sample subjected to 5×1016 He2+/cm2, the highest fluence reached, while similar features were not detected at 9×1015 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.

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

2014-11-01T23:59:59.000Z

269

Thermal conductivity of the electrode gap of a therminonic converter, filled with inert gases, at low pressures  

SciTech Connect (OSTI)

This paper presents experimental data on the thermal conductivity of the electrode gap of a thermionic converter filled with He, Ar, and Xe in the pessure range 40-550 Pa. The need to account for the coefficients of thermal accomodation of the emitter-inert-gas-collector system in this range is shown. The accomodation coefficients for different temperature regimes are measured and expressions are obtained to calculate the heat flux transported by the inert gases in the electrode gap. A diagram of the experimental thermionic converter is shown.

Modin, V.A.; Nikolaev, Y.V.

1986-05-01T23:59:59.000Z

270

Thermal conductivity of anisotropic spin-1/2 two leg ladder: Green’s function approach  

Science Journals Connector (OSTI)

We study the thermal transport of a spin-1/2 two leg antiferromagnetic ladder in the direction of legs. The possible effect of spin-orbit coupling and crystalline electric field are investigated in terms of aniso...

Hamed Rezania; Abdollah Langari…

2014-08-01T23:59:59.000Z

271

Thermal Conductivity Reduction and Thermoelectric Figure of Merit Increase by Embedding Nanoparticles in Crystalline Semiconductors  

E-Print Network [OSTI]

, 63.22.+m, 65.80.+n, 66.60.+a The performance of thermoelectric energy conversion devices depends to achieve high carrier mobility. The lowest thermal conduc- tivity in crystalline solids is generally

272

Thermal shock resistance of solids associated with hyperbolic heat conduction theory  

Science Journals Connector (OSTI)

...damage. Examples are as varied as energy conversion systems, electronic devices and...that was coupled with the local energy balance-[21,22]. Since then...frequency of the molecules within the energy carrier. The thermal relaxation time...

2013-01-01T23:59:59.000Z

273

An optimal guarding scheme for thermal conductivity measurement using a guarded cut-bar technique, part 1 experimental study  

SciTech Connect (OSTI)

In the guarded cut-bar technique, a guard surrounding the measured sample and reference (meter) bars is temperature controlled to carefully regulate heat losses from the sample and reference bars. Guarding is typically carried out by matching the temperature profiles between the guard and the test stack of sample and meter bars. Problems arise in matching the profiles, especially when the thermal conductivitiesof the meter bars and of the sample differ, as is usually the case. In a previous numerical study, the applied guarding condition (guard temperature profile) was found to be an important factor in measurement accuracy. Different from the linear-matched or isothermal schemes recommended in literature, the optimal guarding condition is dependent on the system geometry and thermal conductivity ratio of sample to meter bar. To validate the numerical results, an experimental study was performed to investigate the resulting error under different guarding conditions using stainless steel 304 as both the sample and meter bars. The optimal guarding condition was further verified on a certified reference material, pyroceram 9606, and 99.95% pure iron whose thermal conductivities are much smaller and much larger, respectively, than that of the stainless steel meter bars. Additionally, measurements are performed using three different inert gases to show the effect of the insulation effective thermal conductivity on measurement error, revealing low conductivity, argon gas, gives the lowest error sensitivity when deviating from the optimal condition. The result of this study provides a general guideline for the specific measurement method and for methods requiring optimal guarding or insulation.

Changhu Xing [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Colby Jensen [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Charles Folsom [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Heng Ban [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Douglas W. Marshall [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

2014-01-01T23:59:59.000Z

274

The effect of temperature gradient on the transport phenomenon in roots of maize plants grown under salinity conditions. conductivity and filtration properties  

Science Journals Connector (OSTI)

An analysis of flows through primary root and first node root tissues of plants grown under conditions of salinity and nutrient deficiency induced by temperature gradients was carried out using. a mathematical mo...

J. Michalov

1989-07-01T23:59:59.000Z

275

Effect of boundary scattering on the thermal conductivity of TiNiSn-based half-Heusler alloys  

Science Journals Connector (OSTI)

TiNiSn-based half-Heusler alloys have been of significant interest for their potential as thermoelectric materials. They exhibit promising electronic transport properties as revealed through high Seebeck coefficient and moderate electrical resistivity values. The chief disadvantage of these materials is a comparatively high lattice thermal conductivity. Attempts to “tune” the lattice thermal conductivity (?L) in these materials have led to the comparison and analysis of the thermal conductivity of two series of Ti- and Zr-based half-Heusler alloys. In the first series, Ti1?yZryNiSn0.95Sb0.05, a significant reduction in ?L is observed, with the substitution of large concentrations of Zr (y?25%) at Ti site, which is most likely due to mass fluctuation scattering. In the second series, TiNiSn1?xSbx, a nonsystematic increase in ?L is observed, with minute amounts of Sb doping (x?5%) at the Sn site. Extensive microstructural analysis in a TiNiSn1?xSbx series reveals a correlation between ?L and the average grain diameter in these materials, which is in good agreement with theoretical predictions related to phonon boundary scattering. In addition, a comparison of the calculated phonon mean free path in each of the series of compounds shows some insight into the two different phonon scattering mechanisms.

S. Bhattacharya; M. J. Skove; M. Russell; T. M. Tritt; Y. Xia; V. Ponnambalam; S. J. Poon; N. Thadhani

2008-05-30T23:59:59.000Z

276

A Correction Scheme for Thermal Conductivity Measurement Using the Comparative Cut-bar Technique Based on a 3D Numerical Simulation  

SciTech Connect (OSTI)

As an important factor affecting the accuracy of the thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is due primarily to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on a finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars.

Douglas W. Marshall; Changhu Xing; Charles Folsom; Colby Jensen; Heng Ban

2014-05-01T23:59:59.000Z

277

Electrical and Thermal Conductivity of Ge/Si Quantum Dot Superlattices  

E-Print Network [OSTI]

. Good carrier mobility and electric con- ductivity are important for thermoelectric materials where-Riverside, Riverside, California 92521, USA Recently proposed thermoelectric applications of quantum dot superlattices made of different material systems depend crucially on the values of the electrical and thermal

278

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...

279

A new approach to low-conductivity, environmentally acceptable thermal insulation. Final report  

SciTech Connect (OSTI)

The object of this work was to develop a low-conductivity, economical, environmentally benign insulation. Specific objectives were to develop the following: (1) a very low conductivity use as ``super insulation`` in refrigerators, and (2) a general-purpose insulation for buildings and other applications. The technical goals of this work were to minimize gas phase, solid phase, and radiative conductivity. The novel approach pursued to achieve low gas phase conductivity was to blow foam with a removable gas or vapor, encapsulate the foam panel in a pouch made with a barrier film, and introduce a very low conductivity gas as the insulating gas phase. For super insulation and general-purpose insulation, the gases of choice were xenon and krypton, respectively. To control cost, the gases were present at low pressure, and the insulating panel was encapsulated with an impermeable polymeric film. Solid-phase conductivity was minimized by using low-density, open-cell, polyurethane foam. For super insulation, radiative heat transfer was impeded by placing aluminized Mylar films between relatively transparent 70-mil foam slabs. For general-purpose insulation, it was projected to impede radiative heat transfer by achieving the same very small cell size with open-cell CO{sub 2}-blown foam as is now achieved with closed-cell CO{sub 2}-blown foam.

Buckley, B.; Day, J.; Ferrero-Heredia, M.; Shanklin, E.; Varadarajan, G.; Woodruff, L.

1996-02-01T23:59:59.000Z

280

Steady- and transient-state analyses of fully ceramic microencapsulated fuel loaded reactor core via two-temperature homogenized thermal-conductivity model  

Science Journals Connector (OSTI)

Abstract Fully ceramic microencapsulated (FCM) fuel, a type of accident-tolerant fuel (ATF), consists of TRISO particles randomly dispersed in a SiC matrix. In this study, for a thermal analysis of the FCM fuel with such a high heterogeneity, a two-temperature homogenized thermal-conductivity model was applied by the authors. This model provides separate temperatures for the fuel-kernels and the SiC matrix. It also provides more realistic temperature profiles than those of harmonic- and volumetric-average thermal conductivity models, which are used for thermal analysis of a fuel element in \\{VHTRs\\} having a composition similar to the FCM fuel, because such models are unable to provide the fuel-kernel and graphite matrix temperatures separately. In this study, coupled with a neutron diffusion model, a FCM fuel-loaded reactor core is analyzed via a two-temperature homogenized thermal-conductivity model at steady- and transient-states. The results are compared to those from harmonic- and volumetric-average thermal conductivity models, i.e., we compare keff eigenvalues, power distributions, and temperature profiles in the hottest single-channel at steady-state. At transient-state, we compare total powers, reactivity, and maximum temperatures in the hottest single-channel obtained by the different thermal analysis models. The different thermal analysis models and the availability of fuel-kernel temperatures in the two-temperature homogenized thermal-conductivity model for Doppler temperature feedback cause significant differences as revealed by comparisons.

Yoonhee Lee; Nam Zin Cho

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
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281

General formula for the thermoelectric transport phenomena based on Fermi liquid theory: Thermoelectric power, Nernst coefficient, and thermal conductivity  

Science Journals Connector (OSTI)

On the basis of linear response transport theory, the general expressions for the thermoelectric transport coefficients, such as thermoelectric power (S), Nernst coefficient (?), and thermal conductivity (?), are derived by using Fermi liquid theory. The obtained expression is exact for the most singular term in terms of 1/?k* (?k* being the quasiparticle damping rate). We utilize Ward identities for the heat velocity which is derived by the local energy conservation law. The derived expressions enable us to calculate various thermoelectric transport coefficients in a systematic way, within the framework of the conserving approximation of Baym and Kadanoff. Thus the present expressions are very useful for studying strongly correlated electrons such as high-Tc superconductors, organic metals, and heavy fermion systems, where the current vertex correction (VC) is expected to play important roles. By using the derived expression, we calculate the thermal conductivity ? in a free-dispersion model up to second order with respect to the on-site Coulomb potential U. We find that it is slightly enhanced due to the VC for the heat current, although the VC for electron current makes the conductivity (?) of this system diverge, reflecting the absence of the umklapp process.

Hiroshi Kontani

2003-01-16T23:59:59.000Z

282

A second-order accurate Super TimeStepping formulation for anisotropic thermal conduction  

Science Journals Connector (OSTI)

......on all of them. conduction|MHD|methods: numerical| 1INTRODUCTION...The ideal magnetohydrodynamic (MHD) operator, which is hyperbolic...verified that our radius versus time diagram for the evolution of an SNR matches...solid red line. We solve the MHD equations on a cylindrical mesh......

Chad D. Meyer; Dinshaw S. Balsara; Tariq D. Aslam

2012-05-21T23:59:59.000Z

283

Role of Nanostructures in Reducing Thermal Conductivity below Alloy Limit in Crystalline Solids  

E-Print Network [OSTI]

reduce electrical conductivity, making it ineffective for increasing the material's thermoelectric figure conversion devices depends on the thermoelectric figure of merit (ZT) of a material, which is defined as ZT thermoelectric materials [3-5]. While the original goal for nanostructuring was to increase S2 due to quantum

284

Scaling laws for thermal conductivity of crystalline nanoporous silicon based on molecular dynamics simulations  

E-Print Network [OSTI]

is a potentially efficient ther- moelectric material for energy harvesting applications.11,12 Thermoelectric on the temperature and on the material.13 Good thermoelectric materials feature high electrical conductivity and high to the interdependence among r, S, and k.13 As a thermoelectric material, bulk dense crystalline Si is considered

Pilon, Laurent

285

Thermal conductance of the junction between single-walled carbon nanotubes  

E-Print Network [OSTI]

conductances of the carbon nanotube (CNT) junctions that would be found in a CNT aerogel are predicted using of carbon nanotubes (CNTs) (e.g., aligned films, mats, and aerogels) are candidates for use in electronic issue in all of these applications. Our focus here is related to single-walled CNT aerogels, which

McGaughey, Alan

286

Investigation of the effects of LIFT printing with a KrF-excimer laser on thermally sensitive electrically conductive adhesives  

Science Journals Connector (OSTI)

Laser induced forward transfer is an emerging material deposition technology. We investigated the feasibility of this technique for printing thermally sensitive, electrically conductive adhesives with and without using an intermediate dynamic release layer. A 248 nm KrF-excimer laser was used to print the epoxy-based conductive adhesives containing silver flakes down to 75 ?m dot size. The process is particularly relevant for realizing electrical connections to surface mount devices in the microelectronics industry. Characterization of the printed materials was analyzed by Fourier transform infrared spectroscopy, four-point electrical measurements, die-shear testing and temperature shock testing, to establish that the properties of the adhesive were not affected by direct or indirect laser irradiation. The lack of degradation by the laser onto the adhesives confirms the potential of this technique for interconnection applications.

S M Perinchery; E C P Smits; A Sridhar; P Albert; J van den Brand; R Mandamparambil; I Yakimets; H F M Schoo

2014-01-01T23:59:59.000Z

287

Electron-Phonon Coupling and Thermal Conductance at a Metal-Semiconductor Interface: First-principles Analysis  

E-Print Network [OSTI]

The mechanism of heat transfer and the contribution of electron-phonon coupling to thermal conductance of a metal-semiconductor interface remains unclear in the present literature. We report ab initio simulations of a technologically important titanium silicide (metal) - silicon (semiconductor) interface to estimate the Schottky barrier height (SBH), and the strength of electron-phonon and phonon-phonon heat transfer across the interface. The electron and phonon dispersion relations of TiSi$_2$ with C49 structure and the TiSi$_2$-Si interface are obtained using first-principles calculations within the density functional theory (DFT) framework. These are used to estimate electron-phonon linewidths and the associated Eliashberg function that quantifies coupling. We show that the coupling strength of electrons with interfacial phonon modes is of the same order of magnitude as coupling of electrons to phonon modes in the bulk metal, and its contribution to electron-phonon interfacial conductance is comparable to ...

Sadasivam, Sridhar; Fisher, Timothy S

2015-01-01T23:59:59.000Z

288

Thermal Hall conductivity of marginal Fermi liquids subject to out-of-plane impurities in high-Tc cuprates  

Science Journals Connector (OSTI)

The effect of out-of-plane impurities on the thermal Hall conductivity ?xy of in-plane marginal-Fermi-liquid (MFL) quasiparticles in high-Tc cuprates is examined by following the work on electrical Hall conductivity ?xy by Varma and Abraham [Phys. Rev. Lett. 86, 4652 (2001)]. It is shown that the effective Lorentz force exerted by these impurities is a weak function of energies of the MFL quasiparticles, resulting in nearly the same temperature dependence of ?xy/T and ?xy, indicative of obedience of the Wiedemann-Franz law. The inconsistency of the theoretical result with the experimental one is speculated to be the consequence of the different amounts of out-of-plane impurities in the two YBaCuO samples used for the ?xy and ?xy measurements.

Mei-Rong Li

2002-04-30T23:59:59.000Z

289

Investigation of the thermal conductivity of unconsolidated sand packs containing oil, water, and gas  

E-Print Network [OSTI]

INVESTIGATION OF THE THERNAL CONDUCTIVITY OF UNCONSOLIDATED SAND PACKS CONTAINING OIL, WATER, AND GAS A Thesis David E. Gore Submitted to the Graduate School of the Agricultural and Nechanical College oi' Texas in Partial fulfillment.... EXPERIMENTAL EQUIPMENT AND PROCEDURE All tests were performed on unconsolidated sand packs containing either one, two, or three saturating fluids, Phys- ical properties of the sand and saturating fluids are shown in Tables I and II in the Appendix...

Gore, David Eugene

2012-06-07T23:59:59.000Z

290

Fibrous heat-insulation materials use of the hot wire method to determine thermal conductivity of fibrous heat-insulation materials  

Science Journals Connector (OSTI)

It is desirable to determine the thermal conductivity of materials in the form of plates 30–40 mm thick or of a layer of wool of the same thickness by the hot wire method throughout their service temperature r...

Ya. A. Landa; E. Ya. Litovskii; B. S. Glazachev

291

Thermal Management of Solar Cells  

E-Print Network [OSTI]

a better thermal conductance and when ceramic particles areor ceramic fillers that enhances thermal conductivity. Solid

Saadah, Mohammed Ahmed

2013-01-01T23:59:59.000Z

292

Exploration of coal-based pitch precursors for ultra-high thermal conductivity graphite fibers. Final report  

SciTech Connect (OSTI)

Goal was to explore the utility of coal-based pitch precursors for use in ultra high thermal conductivity carbon (graphite) fibers. From graphite electrode experience, it was established that coal-based pitches tend to form more highly crystalline graphite at lower temperatures. Since the funding was limited to year 1 effort of the 3 year program, the goal was only partially achieved. The coal-base pitches can form large domain mesophase in spite of high N and O contents. The mesophase reactivity test performed on one of the variants of coal-based pitch (DO84) showed that it was not a good candidate for carbon fiber processing. Optimization of WVU`s isotropic pitch process is required to tailor the pitch for carbon fiber processing. The hetero atoms in the coal pitch need to be reduced to improve mesophase formation.

Deshpande, G.V. [Amoco Performance Products, Inc., Alpharetta, GA (United States)

1996-12-27T23:59:59.000Z

293

Experimental investigations and theoretical determination of thermal conductivity and viscosity of Al{sub 2}O{sub 3}/water nanofluid  

SciTech Connect (OSTI)

Experimental investigations and theoretical determination of effective thermal conductivity and viscosity of Al{sub 2}O{sub 3}/H{sub 2}O nanofluid are reported in this paper. The nanofluid was prepared by synthesizing Al{sub 2}O{sub 3} nanoparticles using microwave assisted chemical precipitation method, and then dispersing them in distilled water using a sonicator. Al{sub 2}O{sub 3}/water nanofluid with a nominal diameter of 43 nm at different volume concentrations (0.33-5%) at room temperature were used for the investigation. The thermal conductivity and viscosity of nanofluids are measured and it is found that the viscosity increase is substantially higher than the increase in thermal conductivity. Both the thermal conductivity and viscosity of nanofluids increase with the nanoparticle volume concentration. Theoretical models are developed to predict thermal conductivity and viscosity of nanofluids without resorting to the well established Maxwell and Einstein models, respectively. The proposed models show reasonably good agreement with our experimental results. (author)

Chandrasekar, M.; Suresh, S. [Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli 620 015 (India); Chandra Bose, A. [Nanomaterials Laboratory, National Institute of Technology, Tiruchirappalli 620 015 (India)

2010-02-15T23:59:59.000Z

294

Influence of longitudinal isotope substitution on the thermal conductivity of carbon nanotubes: Results of nonequilibrium molecular dynamics and local density functional calculations  

SciTech Connect (OSTI)

We report reverse nonequilibrium molecular dynamics calculations of the thermal conductivity of isotope substituted (10,10) carbon nanotubes (CNTs) at 300 K. {sup 12}C and {sup 14}C isotopes both at 50% content were arranged either randomly, in bands running parallel to the main axis of the CNTs or in bands perpendicular to this axis. It is found that the systems with randomly distributed isotopes yield significantly reduced thermal conductivity. In contrast, the systems where the isotopes are organized in patterns parallel to the CNTs axis feature no reduction in thermal conductivity when compared with the pure {sup 14}C system. Moreover, a reduction of approximately 30% is observed in the system with the bands of isotopes running perpendicular to the CNT axis. The computation of phonon dispersion curves in the local density approximation and classical densities of vibrational states reveal that the phonon structure of carbon nanotubes is conserved in the isotope substituted systems with the ordered patterns, yielding high thermal conductivities in spite of the mass heterogeneity. In order to complement our conclusions on the {sup 12}C-{sup 14}C mixtures, we computed the thermal conductivity of systems where the {sup 14}C isotope was turned into pseudo-atoms of 20 and 40 atomic mass units.

Leroy, Frédéric, E-mail: f.leroy@theo.chemie.tu-darmstadt.de; Böhm, Michael C., E-mail: boehm@theo.chemie.tu-darmstadt.de [Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, D-64287 Darmstadt (Germany); Schulte, Joachim [Bruker Biospin GmbH, Silberstreifen, D-76287 Rheinstetten (Germany)] [Bruker Biospin GmbH, Silberstreifen, D-76287 Rheinstetten (Germany); Balasubramanian, Ganesh [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)] [Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2014-04-14T23:59:59.000Z

295

Cermet fuel thermal conductivity  

E-Print Network [OSTI]

accommodation coeff. for the gas and surface (unitless) Cp / C?(approximately 5/3 for monoatomic gases) Mean free path of fill gas atoms at I atm. and 'K (atms. -m) Average gas temperature ('K) Prandtl number Gas pressure (atmospheres) INTERFACIAL PRESSURE...

Alvis, John Mark

2012-06-07T23:59:59.000Z

296

The influence of Zn vacancy on thermal conductivity of {beta}-Zn{sub 4}Sb{sub 3}: A molecular dynamics study  

SciTech Connect (OSTI)

The influence of Zn vacancy on lattice thermal conductivity of {beta}-Zn{sub 4}Sb{sub 3} is studied by non-equilibrium molecular dynamics approach. The lattice thermal conductivity of single-crystal bulk {beta}-Zn{sub 4}Sb{sub 3} decreases rapidly when there is Zn vacancy, and then when the vacancy grows, the lattice thermal conductivity decreases further but rather slowly, which suggests a scaling law of k{sub v}{approx}n{sub v}{sup -{alpha}} of Zn atom vacancy (n{sub v}) to lattice thermal conductivity (k{sub vac}). This phenomenon is attributed to the fact that the existence of vacancy scattering can significantly decrease the mean free path. When the Zn atom vacant proportion reaches 10%, that is the vacancy model of {beta}-Zn{sub 4}Sb{sub 3}, the lattice thermal conductivity is 1.32 W/mk along the x-axis and 1.62 W/mk along the z-axis, respectively, which drops by {approx}90% that of its full occupancy model. Therefore, our calculations show that the 10% Zn atom vacancy in {beta}-Zn{sub 4}Sb{sub 3} is the main reason for its exceptionally low thermal conductivity, and the interstitial Zn atoms have little effect on the thermal conductivity of single-crystal {beta}-Zn{sub 4}Sb{sub 3}. - Graphical abstract: The bulk thermal conductivity (k{sub pure}) is 11.88 W/mk along the x-axis and 20.00 W/mk the z-axis. When it is 10% vacancy, namely the vacancy model of {beta}-Zn{sub 4}Sb{sub 3}, the thermal conductivity of {beta}-Zn{sub 4}Sb{sub 3} is 1.32 W/mk along the x-axis and 1.62 W/mk along the z-axis, respectively, which reduces by {approx}90% that of its full occupancy model. Our calculations show that the 10% Zn atom vacancy in the crystal structure of {beta}-Zn{sub 4}Sb{sub 3} is the main reason for its exceptionally low thermal conductivity, and the interstitial Zn atoms have little effect on the thermal conductivity of single-crystal {beta}-Zn{sub 4}Sb{sub 3}. Highlights: Black-Right-Pointing-Pointer The lattice stability of {beta}-Zn{sub 4}Sb{sub 3} decreases remarkably with the growing vacancy. Black-Right-Pointing-Pointer 10% Zn vacancy leads to its low thermal conductivity and structural instability. Black-Right-Pointing-Pointer Interstitial Zn atoms in {beta}-Zn{sub 4}Sb{sub 3} mainly stabilize the crystal structure.

Zhai, Pengcheng [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China) [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China); State Key Laboratory of Advanced Technology of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Li, Guodong; Wen, Pengfei [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China)] [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China); Li, Yao, E-mail: liyao06@126.com [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China)] [Department of Engineering Structure and Mechanics, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Qingjie; Liu, Lisheng [State Key Laboratory of Advanced Technology of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)] [State Key Laboratory of Advanced Technology of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2012-09-15T23:59:59.000Z

297

Nonlinear Electron Heat Conduction Equation and Self similar method for 1-D Thermal Waves in Laser Heating of Solid Density DT Fuel  

E-Print Network [OSTI]

Electron heat conduction is one of the ways that energy transports in laser heating of fusible target material. The aim of Inertial Confinement Fusion (ICF) is to show that the thermal conductivity is strongly dependent on temperature and the equation of electron heat conduction is a nonlinear equation. In this article, we solve the one-dimensional (1-D) nonlinear electron heat conduction equation with a self-similar method (SSM). This solution has been used to investigate the propagation of 1-D thermal wave from a deuterium-tritium (DT) plane source which occurs when a giant laser pulse impinges onto a DT solid target. It corresponds to the physical problem of rapid heating of a boundary layer of material in which the energy of laser pulse is released in a finite initial thickness.

A. Mohammadian Pourtalari; M. A. Jafarizadeh; M. Ghoranneviss

2011-05-22T23:59:59.000Z

298

MEMS test structure for measuring thermal conductivity of thin films L. La Spina, N. Nenadovi*, A. W. van Herwaarden**,  

E-Print Network [OSTI]

from handbook values for the corresponding bulk materials. This is because the thermal transport the one is patterned with the film-to- analyze (FTA). In this case, the thermal resistance can be regarded as a parallel between the thermal resistances of the supporting membrane and of the FTA. Thus, the measured

Technische Universiteit Delft

299

Heat Transfer -1 You are given the following information for a fluid with thermal conductivity of k = 0.0284 W/m-K that  

E-Print Network [OSTI]

Heat Transfer - 1 You are given the following information for a fluid with thermal conductivity the flow is laminar near the wall. a) (30 points) Determine the corresponding heat transfer coefficient the heat transfer coefficient as a function of x. c) (25 points) Determine the average heat transfer

Virginia Tech

300

Divergence of Neighboring Magnetic-Field Lines and Fast-Particle Diffusion in Strong Magnetohydrodynamic Turbulence, with Application to Thermal Conduction in Galaxy Clusters  

Science Journals Connector (OSTI)

Using direct numerical simulations, we calculate the rate of divergence of neighboring magnetic-field lines in different types of strong magnetohydrodynamic turbulence. In the static-magnetic-field approximation, our results imply that tangled magnetic fields in galaxy clusters reduce the electron diffusion coefficient and thermal conductivity by a factor of ?5–10, relative to their values in a nonmagnetized plasma.

Jason Maron; Benjamin D. G. Chandran; Eric Blackman

2004-01-27T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Time-resolved electron thermal conduction by probing of plasma formation in transparent solids with high power subpicosecond laser pulses  

SciTech Connect (OSTI)

This dissertation work includes a series of experimental measurements in a search for better understanding of high temperature (10{sup 4}-10{sup 6}K) and high density plasmas (10{sup 22}-10{sup 24}cm{sup {minus}3}) produced by irradiating a transparent solid target with high intensity (10{sup 13} - 10{sup 15}W/cm{sup 2}) and subpicosecond (10{sup {minus}12}-10{sup {minus}13}s) laser pulses. Experimentally, pump and probe schemes with both frontside (vacuum-plasma side) and backside (plasma-bulk material side) probes are used to excite and interrogate or probe the plasma evolution, thereby providing useful insights into the plasma formation mechanisms. A series of different experiments has been carried out so as to characterize plasma parameters and the importance of various nonlinear processes. Experimental evidence shows that electron thermal conduction is supersonic in a time scale of the first picosecond after laser irradiation, so fast that it was often left unresolved in the past. The experimental results from frontside probing demonstrate that upon irradiation with a strong (pump) laser pulse, a thin high temperature ({approximately}40eV) super-critical density ({approximately}10{sup 23}/cm{sup 3}) plasma layer is quickly formed at the target surface which in turn becomes strongly reflective and prevents further transmission of the remainder of the laser pulse. In the bulk region behind the surface, it is also found that a large sub-critical ({approximately}10{sup 18}/cm{sup 3}) plasma is produced by inverse Bremsstrahlung absorption and collisional ionization. The bulk underdense plasma is evidenced by large absorption of the backside probe light. A simple and analytical model, modified from the avalanche model, for plasma evolution in transparent materials is proposed to explain the experimental results. Elimination of the bulk plasma is then experimentally illustrated by using targets overcoated with highly absorptive films.

Vu, B.T.V.

1994-02-01T23:59:59.000Z

302

Heat dissipation performance of a high-brightness LED package assembly using high-thermal conductivity filler  

Science Journals Connector (OSTI)

This paper presents a thermal analysis and experimental validation of natural convective heat transfer of a high-brightness light-emitting diode (LED) package assembly. The substrate...

Yung, K C; Liem, H; Choy, H S

2013-01-01T23:59:59.000Z

303

Effect of neutral collision and radiative heat-loss function on self-gravitational instability of viscous thermally conducting partially-ionized plasma  

SciTech Connect (OSTI)

The problem of thermal instability and gravitational instability is investigated for a partially ionized self-gravitating plasma which has connection in astrophysical condensations. We use normal mode analysis method in this problem. The general dispersion relation is derived using linearized perturbation equations of the problem. Effects of collisions with neutrals, radiative heat-loss function, viscosity, thermal conductivity and magnetic field strength, on the instability of the system are discussed. The conditions of instability are derived for a temperature-dependent and density-dependent heat-loss function with thermal conductivity. Numerical calculations have been performed to discuss the effect of various physical parameters on the growth rate of the gravitational instability. The temperature-dependent heat-loss function, thermal conductivity, viscosity, magnetic field and neutral collision have stabilizing effect, while density-dependent heat-loss function has a destabilizing effect on the growth rate of the gravitational instability. With the help of Routh-Hurwitz's criterion, the stability of the system is discussed.

Kaothekar, Sachin [School of Studies in Physics, Vikram University, Ujjain-456010, Madhya Pradesh (India); Department of Physics, Mahakal Institute of Technology, Ujjain-456664, Madhya Pradesh (India); Soni, Ghanshyam D. [Government Girls Degree College, Dewas, Madhya Pradesh (India); Chhajlani, Rajendra K. [School of Studies in Physics, Vikram University, Ujjain-456010, Madhya Pradesh (India)

2012-12-15T23:59:59.000Z

304

Anisotropy of elastic moduli, P-wave velocities, and thermal conductivities of Asan Gneiss, Boryeong Shale, and Yeoncheon Schist in Korea  

Science Journals Connector (OSTI)

This paper presents the anisotropic characteristics of the elastic moduli, P-wave velocities, and thermal conductivities of three types of anisotropic rocks, i.e., Asan gneiss, Boryeong shale, and Yeoncheon schist, occurring in Korea. The experiments were conducted on rock samples that show clear evidence of transverse isotropy. Cylindrical core samples with different anisotropy angles were prepared by coring at 15-degree intervals from the transversely isotropic plane using the laboratory directional coring system established for this study. Elastic moduli, P-wave velocities, and thermal conductivities were determined along the sample axis for different anisotropy angles. The anisotropy ratio is defined as the ratio of the properties parallel to the transversely isotropic plane to those perpendicular to the plane, and the anisotropy ratios for the thermal conductivities (K(90°)/K(0°)) of Asan gneiss, Boryeong shale, and Yeoncheon schist were 1.4, 2.1, and 2.5, respectively. The P-wave velocity anisotropy ratios (VP(90°)/VP(0°)) for Asan gneiss, Boryeong shale, and Yeoncheon schist were 1.2, 1.5, and 2.3, respectively. The elastic moduli, P-wave velocities, and thermal conductivities that were obtained were compared with theoretical predictions by mean prediction error (MPE). The correlations between the measured properties were evidently correlated with some minor scatter in the data. The degree of anisotropy measured in this study suggests that ignoring anisotropy in rock properties may mislead to erroneous results. The application of tensorial transformation evaluations revealed that the three types of rocks chosen for this study can be modeled effectively by a transversely isotropic model.

Hanna Kim; Jung-Woo Cho; Insun Song; Ki-Bok Min

2012-01-01T23:59:59.000Z

305

Morphology effects on non-isotropic thermal conduction of aligned single- and multi-walled carbon nanotubes in polymer nanocomposites  

E-Print Network [OSTI]

Carbon nanotube (CNT)?CNT contact and CNT distribution effects on anisotropic thermal transport in aligned CNT?polymer nanocomposites (PNCs) are studied using an off-lattice Monte Carlo numerical simulation. Inter-CNT ...

Duong, Hai M.

306

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

SciTech Connect (OSTI)

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.

Kolodiazhnyi, T., E-mail: kolodiazhnyi.taras@nims.go.jp; Sakurai, H.; Vasylkiv, O.; Borodianska, H. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4M1 (Canada)

2014-03-17T23:59:59.000Z

307

TRANSPORT INVOLVING CONDUCTING FIBERS IN A NON-CONDUCTING MATRIX  

E-Print Network [OSTI]

result is a material with high electrical conductivity and low thermal conductivity. Transport Models,2 , J. Rozen3 Introduction Thermal and electrical transport through a low-conductivity matrix containing conversion devices high electrical conductivity and low thermal conductivity are preferred for superior

Walker, D. Greg

308

Thermal history of Bakken shale in Williston basin  

SciTech Connect (OSTI)

Stratigraphic and thermal conductivity data were combined to analyze the thermostratigraphy of the Williston basin. The present thermostratigraphy is characterized by geothermal gradients of the order of 60 mK/m in the Cenozoic and Mesozoic units, and 30 mK/m in the Paleozoic units. The differences in geothermal gradients are due to differences in thermal conductivities between the shale-dominated Mesozoic and Cenozoic units and the carbonate-dominated Paleozoic units. Subsidence and compaction rates were calculated for the basin and were used to determine models for time vs. depth and time vs. thermal conductivity relationships for the basin. The time/depth and time/conductivity relationships include factors accounting for thermal conductivity changes due to compaction, cementation, and temperature. The thermal history of the Bakken shale, a primary oil source rock in the Williston basin, was determined using four different models, and values for Lopatin's time-temperature index (TTI) were calculated for each model. The first model uses a geothermal gradient calculated from bottom-hole temperature data, the second uses present-day thermostratigraphy, the third uses the thermostratigraphic relationship determined in this analysis, and the fourth modifies the third by including assumed variations in continental heat flow. The thermal histories and the calculated TTI values differ markedly among the models with TTI values differing by a factor of about two between some models.

Gosnold, W.D. Jr.; Lefever, R.D.; Crashell, J.J. (Univ. of North Dakota, Grand Forks (USA))

1989-12-01T23:59:59.000Z

309

Review of Helium and Xenon Pure Component and Mixture Transport Properties and Recommendation of Estimating Approach for Project Prometheus (Viscosity and Thermal Conductivity)  

SciTech Connect (OSTI)

The selected configuration for the Project Prometheus Space Nuclear Power Plant was a direct coupling of Brayton energy conversion loop(s) to a single reactor heat source through the gas coolant/working fluid. A mixture of helium (He) and xenon (Xe) gas was assumed as the coolant/working fluid. Helium has superior thermal conductivity while xenon is added to increase the gas atomic weight to benefit turbomachinery design. Both elements have the advantage of being non-reactive. HeXe transport properties (viscosity and thermal conductivity) were needed to calculate pressure drops and heat transfer rates. HeXe mixture data are limited, necessitating the use of semi-empirical correlations to calculate mixture properties. Several approaches are available. Pure component properties are generally required in the mixture calculations. While analytical methods are available to estimate pure component properties, adequate helium and xenon pure component data are available. This paper compares the sources of pure component data and the approaches to calculate mixture properties. Calculated mixture properties are compared to the limited mixture data and approaches are recommended to calculate both pure component and mixture properties. Given the limited quantity of HeXe mixture data (all at one atmosphere), additional testing may have been required for Project Prometheus to augment the existing data and confirm the selection of mixture property calculation methods.

Haire, Melissa A.; Vargo, David D. [Bechtel Bettis, Inc., Bettis Atomic Power Laboratory, P.O. Box 79, West Mifflin, PA 15122 (United States)

2007-01-30T23:59:59.000Z

310

Besides these questions regarding the efficiency of condensation or thermal conduction in the inner flow, we note that there are other important questions regarding EC theory and implementation, including  

E-Print Network [OSTI]

Besides these questions regarding the efficiency of condensation or thermal conduction in the inner,12], but irradiation efficiency ~uncertain EC evaporation/condensation [13,14,15,16] between thermally-coupled disk setting to study accretion ­ a high mass supply rate (via Roche- lobe overflow [1,2]) avoids onset

California at Santa Cruz, University of

311

Low-temperature thermal conductivity of antiferromagnetic S?=?1/2 chain material CuCl{sub 2}·2((CH{sub 3}){sub 2}SO)  

SciTech Connect (OSTI)

We study the heat transport of S?=?1/2 chain compound CuCl{sub 2}·2((CH{sub 3}){sub 2}SO) along the b axis (vertical to the chain direction) at very low temperatures. The zero-field thermal conductivity (?) shows a distinct kink at about 0.9?K, which is related to the long-range antiferromagnetic (AF) transition. With applying magnetic field along the c axis, ?(H) curves also show distinct changes at the phase boundaries between the AF and the high-field disordered states. These results indicate a strong spin-phonon interaction and the magnetic excitations play a role in the b-axis heat transport as phonon scatterers.

Ke, W. P.; Zhang, F. B.; Zhao, Z. Y.; Fan, C.; Sun, X. F., E-mail: xfsun@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, J. [Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhao, X., E-mail: xiazhao@ustc.edu.cn [School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2014-05-07T23:59:59.000Z

312

Measuring the Impact of Experimental Parameters upon the Estimated Thermal Conductivity of Closed-Cell Foam Insulation Subjected to an Accelerated Aging Protocol ? Two Year Results  

SciTech Connect (OSTI)

The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C 1303 standard test method have led to a broad ruggedness test. This test includes the aging of full size insulation specimens for time periods up to five years for later comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. This paper will compare the results after two years of full-thickness aging.

Stovall, Therese K [ORNL] [ORNL

2009-01-01T23:59:59.000Z

313

Measuring the Impact of Experimental Parameters upon the Estimated Thermal Conductivity of Closed-Cell Foam Insulation Subjected to an Accelerated Aging Protocol  

SciTech Connect (OSTI)

The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Recent efforts to produce a more prescriptive version of the ASTM standard test method have led to the initiation of a broad ruggedness test. This test includes the aging of full size insulation specimens for time periods up to five years for later comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. This paper will cover the structure of the ruggedness test and provide a glimpse of some early trends

Stovall, Therese K [ORNL] [ORNL; Bogdan, mary [Honeywell, Inc.] [Honeywell, Inc.

2008-01-01T23:59:59.000Z

314

Simplified modeling of liquid sodium medium with temperature and velocity gradient using real thermal-hydraulic data. Application to ultrasonic thermometry in sodium fast reactor  

SciTech Connect (OSTI)

In the framework of the French R and D program for the Generation IV reactors and specifically for the sodium cooled fast reactors (SFR), studies are carried out on innovative instrumentation methods in order to improve safety and to simplify the monitoring of fundamental physical parameters during reactor operation. The aim of the present work is to develop an acoustic thermometry method to follow up the sodium temperature at the outlet of subassemblies. The medium is a turbulent flow of liquid sodium at 550 Degree-Sign C with temperature inhomogeneities. To understand the effect of disturbance created by this medium, numerical simulations are proposed. A ray tracing code has been developed with Matlab Copyright-Sign in order to predict acoustic paths in this medium. This complex medium is accurately described by thermal-hydraulic data which are issued from a simulation of a real experiment in Japan. The analysis of these results allows understanding the effects of medium inhomogeneities on the further thermometric acoustic measurement.

Massacret, N.; Jeannot, J. P. [DEN/DTN/STPA/LIET, CEA Cadarache, Saint Paul Lez Durance (France); Moysan, J.; Ploix, M. A.; Corneloup, G. [Aix-Marseille Univ, LMA UPR 7051 CNRS, site LCND, 13625 Aix-en-Provence (France)

2013-01-25T23:59:59.000Z

315

Microconvection effects at double?diffusive gradient zone boundaries  

Science Journals Connector (OSTI)

Microconvection in double?diffusive gradient zones is predicted to occur near the zone boundaries because of effects of boundary undulation and temperature modulation caused by impinging thermals in adjacent convecting zones. The equations that govern convective motion in a double?diffusive horizontal slab are solved for boundary conditions that incorporate these effects. Solution of these equations predicts a weakened salinity gradient near the gradient zone boundary between the rising thermals. When the salinity gradient is too weak instability occurs taking the form of descending plumes which are seen in experiments.

John R. Hull; Yojana Katti

1988-01-01T23:59:59.000Z

316

Ocean Thermal Gradient Hydraulic Power Plant  

Science Journals Connector (OSTI)

...for the probable life of the earth, only...low-pressure steam turbines pSrhaps hun-dreds...con-ventional hydraulic turbine under gravity flow...horizontally and the remaining available energy...through a hydraulic turbine to generatepower...between the liquid and gas-eous phases, with...

Earl J. Beck

1975-07-25T23:59:59.000Z

317

1981). Their basic solution is to find a suitable backfilling material to minimize the contact resistance and to maintain high ground thermal conductivity around the cable even under very  

E-Print Network [OSTI]

#12;1981). Their basic solution is to find a suitable backfilling material to minimize the contact resistance and to maintain high ground thermal conductivity around the cable even under very dry ground contact resistance or soil dry-out or both. This paper presents a mathematical model describing

Oak Ridge National Laboratory

318

Joining of Tungsten Armor Using Functional Gradients  

SciTech Connect (OSTI)

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.

John Scott O'Dell

2006-12-31T23:59:59.000Z

319

Fast Self-Healing Gradients  

E-Print Network [OSTI]

We present CRF-Gradient, a self-healing gradient algorithm that provably reconfigures in O(diameter) time. Self-healing gradients are a frequently used building block for distributed self-healing systems, but previous ...

Beal, Jacob

320

Steep Gradient Flume | Open Energy Information  

Open Energy Info (EERE)

Steep Gradient Flume Steep Gradient Flume Jump to: navigation, search Basic Specifications Facility Name Steep Gradient Flume Overseeing Organization University of Iowa Hydrodynamic Testing Facility Type Flume Length(m) 20.1 Beam(m) 0.9 Depth(m) 0.5 Cost(per day) Contact POC Special Physical Features Tilting flume from -1.5 to +16% slope; <3mm sedimentation recirculation capabilities; instrumentation rails Towing Capabilities Towing Capabilities None Wavemaking Capabilities Wavemaking Capabilities None Channel/Tunnel/Flume Channel/Tunnel/Flume Yes Recirculating Yes Wind Capabilities Wind Capabilities None Control and Data Acquisition Cameras Yes Number of Color Cameras 1 Available Sensors Acoustics, Flow, Thermal, Turbulence, Velocity Data Generation Capability Real-Time Yes

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Report on workshop on thermal property measurements  

SciTech Connect (OSTI)

Results of thermogravimetric analysis of basalt is discussed. Heat capacity, thermal conductivity and thermal expansion are specifically addressed. (CBS)

Robertson, E.C.

1987-01-01T23:59:59.000Z

322

Were Archaean continental geothermal gradients much steeper than today?  

Science Journals Connector (OSTI)

... km depth) did not generally exceed 800 C. From this they deduce a surface geothermal gradient of less than 23 C km'1 compared with 17 C km'1 in ... P-T determinations on Archaean granulites (summarised in ref. 2) their calculation of the geothermal gradient does not comply with conductive properties and distribution of heat producing elements within the ...

S. A. DRURY

1978-08-17T23:59:59.000Z

323

Design of a novel conduction heating based stress-thermal cycling apparatus for composite materials and its utilization to characterize composite microcrack damage thresholds  

E-Print Network [OSTI]

???????????..?????????47 viii CHAPTER Page 4.4 Thermal Loading Combined with Bending Conditions?????? 49 4.5 Thermo-Viscoelastic Constitutive....1 Characterization of Crack Formation and Propagation Mechanism?. 93 6.2 Analytical Study of Time Dependent Non-Isothermal Linear Thermo-Viscoelasticity??????????????????...94 6.3 Initial Damage Characterization??????????????.. 101 6.3.1 Cryogenic Temperature...

Ju, Jaehyung

2006-10-30T23:59:59.000Z

324

A parametric study of thermomechanical behavior of functionally gradient materials  

E-Print Network [OSTI]

(FSDT) that accounts for the transverse shear strains and the rotations, coupled with a three dimensional heat conduction equation is formulated for a functionally gradient plate. Both problems are studied by varying the volume fraction of a ceramic...

Chin, Che-Doong

1996-01-01T23:59:59.000Z

325

Hot Pot Contoured Temperature Gradient Map  

SciTech Connect (OSTI)

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

Lane, Michael

2013-06-28T23:59:59.000Z

326

Hot Pot Contoured Temperature Gradient Map  

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

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

Lane, Michael

327

Thermal insulations using vacuum panels  

DOE Patents [OSTI]

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.

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

1991-07-16T23:59:59.000Z

328

Recurrent policy gradients  

Science Journals Connector (OSTI)

......for recurrent neural networks Recurrent policy gradients Daan Wierstra Alexander Forster...POMDPs) is a challenge as it requires policies with an internal state. Traditional approaches...offer a natural framework for dealing with policy learning using hidden state and require......

Daan Wierstra; Alexander Förster; Jan Peters; Jürgen Schmidhuber

2010-10-01T23:59:59.000Z

329

Thermal Characterization of Graphitic Carbon Foams for Use in Thermal Storage Applications.  

E-Print Network [OSTI]

?? Highly conductive graphitic foams are currently being studied for use as thermal conductivity enhancers (TCEs) in thermal energy storage (TES) systems. TES systems store… (more)

Drummond, Kevin P.

2012-01-01T23:59:59.000Z

330

Thermal unobtainiums? The perfect thermal conductor and  

E-Print Network [OSTI]

contribute to thermal resistance · Isotopically pure diamond has highest thermal conductivity of any material materials: disordered layered crystals Conclude with some thoughts on promising, high-risk, research even in a computer model. #12;Thermal resistance is created by Umklapp scattering (U

Braun, Paul

331

Transport involving conducting fibers in a non-conducting matrix R. A. Hansela  

E-Print Network [OSTI]

result is a material with high electrical conduc- tivity and low thermal conductivity. If we consider, conducting fibers, thin-film devices 1. Introduction Thermal and electrical transport through a low to predict conductance of the combined system. However, if the two materials are similar in conductivity

Walker, D. Greg

332

Energy in density gradient  

E-Print Network [OSTI]

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 cylindric 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 ...

Vranjes, J

2015-01-01T23:59:59.000Z

333

High-gradient compact linear accelerator  

DOE Patents [OSTI]

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.

Carder, Bruce M. (205 Rogue River Hwy., Gold Hill, OR 97525)

1998-01-01T23:59:59.000Z

334

High-gradient compact linear accelerator  

DOE Patents [OSTI]

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.

Carder, B.M.

1998-05-26T23:59:59.000Z

335

Gradient Resources | Open Energy Information  

Open Energy Info (EERE)

Resources Resources Jump to: navigation, search Logo: Gradient Resources Name Gradient Resources Address 9670 Gateway Drive, Suite 200 Place Reno, Nevada Zip 89521 Sector Geothermal energy Year founded 1991 Company Type For Profit Phone number (775) 284-8842 Website http://www.gradient.com/ Region Rockies Area References Gradient Resources Website[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! Gradient Resources is a company based in Reno, Nevada. Gradient Resources is engaged in the exploration and development of geothermal resources as well as the construction, ownership and operation of geothermal power plants. The Company is headquartered in Reno, Nevada with a regional office, drilling operations center, and well-cementing

336

Hierarchically deflated conjugate gradient  

E-Print Network [OSTI]

We present a multi-level algorithm for the solution of five dimensional chiral fermion formulations, including domain wall and Mobius Fermions. The algorithm operates on the red-black preconditioned Hermitian operator, and directly accelerates conjugate gradients on the normal equations. The coarse grid representation of this matrix is next-to-next-to-next-to-nearest neighbour and multiple algorithmic advances are introduced, which help minimise the overhead of the coarse grid. The treatment of the coarse grids is purely four dimensional, and the bulk of the coarse grid operations are nearest neighbour. The intrinsic cost of most of the coarse grid operations is therefore comparable to those for the Wilson case. We also document the implementation of this algorithm in the BAGEL/Bfm software package and report on the measured performance gains the algorithm brings to simulations at the physical point on IBM BlueGene/Q hardware.

P A Boyle

2014-02-11T23:59:59.000Z

337

Variable pressure thermal insulating jacket  

DOE Patents [OSTI]

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.

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

1994-09-20T23:59:59.000Z

338

Optimized Structures for Low-Profile Phase Change Thermal Spreaders  

E-Print Network [OSTI]

of High-Thermal-Conductivity Aluminum Nitride Ceramics”,for a ceramic isolating material and the associated thermal

Sharratt, Stephen A.

2012-01-01T23:59:59.000Z

339

Conduction cooled tube supports  

DOE Patents [OSTI]

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.

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

1984-01-01T23:59:59.000Z

340

Gradient Sliding for Composite Optimization  

E-Print Network [OSTI]

Noname manuscript No. (will be inserted by the editor). Gradient Sliding for Composite Optimization. Guanghui Lan the date of receipt and acceptance should ...

2014-06-11T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Solar energy storage by salinity gradient solar pond: Pilot plant construction and gradient control  

Science Journals Connector (OSTI)

An experimental solar pond pilot plant was constructed in Solvay-Martorell, facilities, Catalonia (NE part of the Iberian Peninsula) to capture and store solar energy. The body of the pond is a cylindrical reinforced concrete tank, 3 m height, 8 m diameter and total area of 50 m2. Salinity and thermal gradient were properly established by using the salinity distribution methodology. The gradient in the pond was maintained by feeding salt (NaCl) through a cylindrical salt charger to the bottom at a height of 80 cm from the pond floor. Continuous surface washing using tap water supply maintained the salinity of the top convective layer at a low level and compensate loses by evaporation. An acidification method by addition of \\{HCl\\} at different heights was used to control the clarity of the pond. The salinity gradient was fully established on 30 September 2009 and has been maintained until the date. After winter time (February 2010), the pond warms up and the temperature increased continuously until it reached its maximum (55 °C) in August 2010. The salinity gradient observed great stability after one year of continuous control and maintenance and under different weather conditions.

César Valderrama; Oriol Gibert; Jordina Arcal; Pau Solano; Aliakbar Akbarzadeh; Enric Larrotcha; José Luis Cortina

2011-01-01T23:59:59.000Z

342

Salt Gradient Solar Pond for Solar Heat Collection and Lang Term Storage  

Science Journals Connector (OSTI)

Work is described concerning the instrumentation, thermal modelling and laboratory tests on a salt gradient solar pond to be used for heat collection and storage. A densitameter capable of measuring the salinity....

V. Phillips; P. J. Unsworth; N. A. Al-Saleh

1983-01-01T23:59:59.000Z

343

An innovative approach to heat extraction from a salinity gradient solar pond to enhance overall efficiency.  

E-Print Network [OSTI]

??A solar pond is a simple and low-cost solar collector with long-term thermal storage. It utilizes a large body of salinity gradient water to absorb… (more)

Yaakob, Y

2013-01-01T23:59:59.000Z

344

Spatially resolved lasers using a glassy cholesteric liquid crystal film with lateral pitch gradient  

E-Print Network [OSTI]

Spatially resolved lasers using a glassy cholesteric liquid crystal film with lateral pitch crystal CLC lasers, a lateral pitch gradient was introduced by thermally activated diffusion across efficiencies, 0.2%­1.5%, are superior to those reported to date for gradient-pitch CLC lasers. © 2011 American

Chen, Shaw H.

345

Dielectric-Lined High-Gradient Accelerator Structure  

SciTech Connect (OSTI)

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.

Jay L. Hirshfield

2012-04-24T23:59:59.000Z

346

Device for thermal transfer and power generation  

DOE Patents [OSTI]

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.

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

2011-04-19T23:59:59.000Z

347

Conductive Thermal Interaction in Evaporative Cooling Process  

E-Print Network [OSTI]

It has long been recognized that evaporative cooling is an effective and logical substitute for mechanical cooling in hot-arid climates. This paper explores the application of evaporative coolers to the hot-humid climates using a controlled...

Kim, B. S.; Degelman, L. O.

1990-01-01T23:59:59.000Z

348

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network [OSTI]

RTG refers to radioisotope thermoelectric generator with aRTG refers to radioisotope thermoelectric generator with a

Wang, Zhaojie

2012-01-01T23:59:59.000Z

349

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network [OSTI]

2), 1-19. Buresch, M. , Photovoltaic energy systems. 1983; penergy industry, monocrystalline silicon was used as the first photovoltaic

Wang, Zhaojie

2012-01-01T23:59:59.000Z

350

Definition: Hydraulic Conductivity | Open Energy Information  

Open Energy Info (EERE)

Conductivity Conductivity Jump to: navigation, search Dictionary.png Hydraulic Conductivity Hydraulic conductivity is a physical property which measures the ability of the material to transmit fluid through pore spaces and fractures in the presence of an applied hydraulic gradient. Darcy's Law defines the hydraulic conductivity as the ratio of the average velocity of a fluid through a cross-sectional area (Darcy's velocity) to the applied hydraulic gradient.[1] View on Wikipedia Wikipedia Definition Hydraulic conductivity, symbolically represented as, is a property of vascular plants, soil or rock, that describes the ease with which a fluid (usually water) can move through pore spaces or fractures. It depends on the intrinsic permeability of the material and on the degree of

351

Conductive Polymers  

SciTech Connect (OSTI)

Electroluminescent devices such as light-emitting diodes (LED) and high-energy density batteries. These new polymers offer cost savings, weight reduction, ease of processing, and inherent rugged design compared to conventional semiconductor materials. The photovoltaic industry has grown more than 30% during the past three years. Lightweight, flexible solar modules are being used by the U.S. Army and Marine Corps for field power units. LEDs historically used for indicator lights are now being investigated for general lighting to replace fluorescent and incandescent lights. These so-called solid-state lights are becoming more prevalent across the country since they produce efficient lighting with little heat generation. Conductive polymers are being sought for battery development as well. Considerable weight savings over conventional cathode materials used in secondary storage batteries make portable devices easier to carry and electric cars more efficient and nimble. Secondary battery sales represent an $8 billion industry annually. The purpose of the project was to synthesize and characterize conductive polymers. TRACE Photonics Inc. has researched critical issues which affect conductivity. Much of their work has focused on production of substituted poly(phenylenevinylene) compounds. These compounds exhibit greater solubility over the parent polyphenylenevinylene, making them easier to process. Alkoxy substituted groups evaluated during this study included: methoxy, propoxy, and heptyloxy. Synthesis routes for production of alkoxy-substituted poly phenylenevinylene were developed. Considerable emphasis was placed on final product yield and purity.

Bohnert, G.W.

2002-11-22T23:59:59.000Z

352

Field Investigations And Temperature-Gradient Drilling At Marine Corps  

Open Energy Info (EERE)

Investigations And Temperature-Gradient Drilling At Marine Corps Investigations And Temperature-Gradient Drilling At Marine Corps Air-Ground Combat Center (Mcagcc), Twenty-Nine Palms, Ca Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Field Investigations And Temperature-Gradient Drilling At Marine Corps Air-Ground Combat Center (Mcagcc), Twenty-Nine Palms, Ca Details Activities (4) Areas (1) Regions (0) Abstract: The U.S. Navy's Geothermal Program Office (GPO) has been conducting geothermal exploration activities in the Camp Wilson area of Marine Corps Air-Ground Combat Center (MCAGCC), Twenty-nine Palms, CA, for almost two years. Work has included self-potential (SP) surveys, fault structure analyses using LiDAR surveys, and drilling and assessment of five (5) temperature-gradient holes. For several decades the GPO has worked

353

High field gradient particle accelerator  

DOE Patents [OSTI]

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.

Nation, J.A.; Greenwald, S.

1989-05-30T23:59:59.000Z

354

High field gradient particle accelerator  

DOE Patents [OSTI]

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.

Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

1989-01-01T23:59:59.000Z

355

Tunable thermal link  

DOE Patents [OSTI]

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.

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

2014-07-15T23:59:59.000Z

356

Correlated Knowledge Gradients: Example alternatives  

E-Print Network [OSTI]

Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0;Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0 num measurements log(KGfactor) 0 10 20 30 0 0.5 1 1.5 2 num measurements opportunitycost #12;Correlated Knowledge

Keinan, Alon

357

Thermoelectrics Combined with Solar Concentration for Electrical and Thermal Cogeneration  

E-Print Network [OSTI]

Since the ceramic wafers have a high thermal conductivity,easily altered ceramic blocks all had a thermal conductivityCeramics. Available Online: http://www.dynacer.com/thermal_

Jackson, Philip Robert

2012-01-01T23:59:59.000Z

358

October 2011 SDI FEP Issues Heat Conduction Issues (HC)  

E-Print Network [OSTI]

the heaters. Background: Halite thermal conductivity (k) is inversely related to porosity. The higher porosity additional information on the higher temperature-lower thermally conductive nature of halite and its affect on distal temperatures. Background: Halite thermal k is inversely related to temperature. A higher

359

Gas Exchange, Partial Pressure Gradients,  

E-Print Network [OSTI]

Gas Exchange, Partial Pressure Gradients, and the Oxygen Window Johnny E. Brian, Jr., M of circulatory and gas transport physiology, and the best place to start is with normobaric physiology. LIFE affect the precise gas exchange occurring in individual areas of the lungs and body tissues. To make

Riba Sagarra, Jaume

360

The Extended Finite Element Method for High Gradient Solutions  

E-Print Network [OSTI]

Outline Enrichment functions for high gradient solutions Motivation High gradient inside the domain (Shocks) High gradient at the boundary (boundary layers) Optimal set of enrichment functions Numerical for high gradient solutions Outline Enrichment functions for high gradient solutions Motivation High

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Design, prototyping, and testing of an apparatus for establishing a linear temperature gradient in experimental fish tanks  

E-Print Network [OSTI]

Immunology researchers require a new type of fish tank that provides a linear thermal gradient for experimental zebrafish in order to improve the accuracy and validity of their research. Zebrafish require the ability to ...

Kadri, Romi Sinclair

2014-01-01T23:59:59.000Z

362

Molecular Dynamics Simulations of Heat Conduction in Nanostructures: Effect of Heat Bath  

E-Print Network [OSTI]

temperature profile and thermal conductivity in homogeneous materials. Furthermore, the thermal rectification) The low thermal conductivity of SiNWs is of particular interest for thermoelectric application.10 point of view. On the one hand, superior thermal conductivity has been observed in graphene1

Li, Baowen

363

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....

364

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...

365

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...

366

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....

367

Design, construction, and initial operation of the Los Alamos National Laboratory salt-gradient solar pond  

SciTech Connect (OSTI)

A 232 m/sup 2/ solar pond was constructed at Los Alamos National Laboratory for the purpose of studying pond hydrodynamics on a large scale and to complement the flow visualization and one-dimensional pond simulator experiments that are ongoing at the Laboratory. Design methods and construction techniques, some of which are unique to this pond, are described in detail. The pond was excavated from a soft volcanic rock known as tuff; such rock forms a large fraction of the Los Alamos area surface geology. Because tuff has a small thermal conductivity, little insulation was required to reduce perimeter energy losses. In addition, the strength of tuff permitted the pond to be built with vertical side walls; this design eliminated local side wall convection in the gradient zone that is possible with sloping side walls. Instrumentation in the pond consists of traversing and fixed rakes of thermometers and salinity probes, an underwater pyranometer, and a weather station. The traversing rake is a wheeled trolley driven vertically on a rectangular rail. Installed on the trolley are coplanar platinum RTDs, a point conductivity probe, and an induction salinometer. The stationary rake supports 28 thermocouples and 28 sample-fluid withdrawal taps located every 10 cm. About 127 T of sodium chloride has been introduced and is nearly dissolved. A 120-cm-thick salinity gradient was established and the pond is heating. Preliminary results indicate a lower-convective-zone heating rate of 1.2/sup 0/C/day during the pond's first month of operation. Recommendations on pond design, construction, and instrumentation are presented.

Jones, G.F.; Meyer, K.A.; Hedstrom, J.C.; Dreicer, J.S.; Grimmer, D.P.

1983-01-01T23:59:59.000Z

368

Faster Time Response by the Use of Wire Electrodes in Capacitive Salinity Gradient Energy Systems  

Science Journals Connector (OSTI)

Comparing salinity gradient power to other ocean power sources, such as wind, ocean currents, wave, tidal streams, and thermal gradients, it is supreme partly in that it has the second largest power potential, but foremost because it is focused at river deltas (rather than being distributed over the ocean areas across the world). ... We also studied the asymmetric behavior of response time in concentrated saline solution and dilute saline solution that is reported for our branch of technologies. ... solns. of different salinities. ...

Odne S. Burheim; Fei Liu; Bruno B. Sales; Olivier Schaetzle; Cees J. N. Buisman; Hubertus V. M. Hamelers

2012-08-28T23:59:59.000Z

369

Thermal Stress Analysis of LCA-based Solid Oxide Fuel Cells.  

E-Print Network [OSTI]

??This research characterizes the thermal stress resulting from temperature gradients in hybrid solid oxide fuel cells that are processed using a novel oxide powder slurry… (more)

LeMasters, Jason Augustine

2004-01-01T23:59:59.000Z

370

Model Studies of Pore Stability and Evolution in Thermal Barrier Coatings (TBCs)  

E-Print Network [OSTI]

N. Katz, “Advanced Ceramics: Thermal Barrier Coatings BeatConductivity of Advanced Ceramic Thermal Barrier CoatingsFatigue Testing of Ceramic Thermal Barrier Coatings,” NASA/

Glaeser, A M

2008-01-01T23:59:59.000Z

371

Salinity Gradient Energy at River Mouths  

Science Journals Connector (OSTI)

Salinity Gradient Energy at River Mouths ... River mouths are potentially abundant locations for the exploitation of the clean and renewable salinity gradient energy (SGE) as here perpetually fresh water mixes with saline seawater. ...

Oscar Alvarez-Silva; Christian Winter; Andres F. Osorio

2014-09-03T23:59:59.000Z

372

Revisiting an Old Concept: The Gradient Wind  

Science Journals Connector (OSTI)

The gradient wind is defined as a horizontal wind having the same direction as the geostrophic wind but with a magnitude consistent with a balance of three forces: the pressure gradient force, the Coriolis force, and the centrifugal force arising ...

Keith F. Brill

2014-04-01T23:59:59.000Z

373

Design and production of efficient current leads for 1500-A, 50-Hz service in a 77-4 K temperature gradient  

SciTech Connect (OSTI)

Two arrays of BSCCO 2223 bars were designed and produced for use in current leads for a power utility fault-current limiter operating at 4 K. Each conduction-cooled array, consisting of four parallel bars arranged within a 100-mm-diameter boundary, delivered 1,500 A peak, 50-Hz AC through a 77-4 K temperature gradient while dissipating < 0.2 W. The sinter-forged bars displayed DC critical current densities of 950--1,300 A/cm{sup 2} at 77 K and > 5,000 A/cm{sup 2} at 4 K. Magnetic field sensitivity was relatively low. Thermal conductivity tests showed values higher than literature values for polycrystalline BSCCO 2223 made by other processes.

Balachandran, U.; Youngdahl, C.A.; Lanagan, M.T. [and others

1994-10-01T23:59:59.000Z

374

Determination of dispersivities from a natural-gradient dispersion test  

E-Print Network [OSTI]

, and radioactive wastes. Contaminant hydrogeology is presently a focal point in the realm of hydrologic modeling. Generally, models are designed to represent simplified versions of reality and The style and format of this document was taken from the Journal... dispersivities, v ia a graphical approach, from a natural-gradient dispersion test in which artificial pollution was injected into an aquifer. The dispersion test was conducted by Sud icky et al. (1983) in order to characterize the dispersive properties...

Hoover, Caroline Marie

1985-01-01T23:59:59.000Z

375

Thermal Energy Storage in Metal Foams filled with Paraffin Wax.  

E-Print Network [OSTI]

??Phase change materials (PCM) such as paraffin wax are known to exhibit slow thermal response due to their relatively low thermal conductivity. In this study,… (more)

Vadwala, Pathik

2012-01-01T23:59:59.000Z

376

Bayesian Policy Gradient and Actor-Critic Algorithms Bayesian Policy Gradient and Actor-Critic Algorithms  

E-Print Network [OSTI]

Bayesian Policy Gradient and Actor-Critic Algorithms Bayesian Policy Gradient and Actor Yaakov Engel yakiengel@gmail.com Editor: Abstract Policy gradient methods are reinforcement learning algorithms that adapt a param- eterized policy by following a performance gradient estimate. Many

Paris-Sud XI, Université de

377

E-Print Network 3.0 - ac conductivity studies Sample Search Results  

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

Conductivity, Molecular... Dynamics Simulation, Thermal Conductance ABSTRACT Several heat transfer problems related to single... function between carbon and carbon within a...

378

Proton conducting ceramic membranes for hydrogen separation  

DOE Patents [OSTI]

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.

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

2011-09-06T23:59:59.000Z

379

Europium-doped Pyrochlores for Use as Thermographic Phosphors in Thermal Barrier Coatings  

E-Print Network [OSTI]

temperatures and better efficiency · Two primary characteristics for coating: low thermal conductivity and high conductivities and high thermal expansion coefficients making them attractive as materials in thermal barrier · Selected compounds have low thermal conductivity, high melting points, and adequate thermal expansion

Walker, D. Greg

380

Simultaneous increase in electrical conductivity and Seebeck coefficient in highly Boron-doped nanocrystalline Si  

E-Print Network [OSTI]

, and is the thermal conductivity. Although traditionally ZT remained low (below one for most materials), over the last thermoelectric materials due to such a significant reduction in their thermal conductivity compared to bulk Si in their thermal conductivity [1, 2]. Silicon nanostructures have also been recently proposed as efficient

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Thermal ignition combustion system  

DOE Patents [OSTI]

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.

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

1988-04-19T23:59:59.000Z

382

Thermal ignition combustion system  

SciTech Connect (OSTI)

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.

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

1988-01-01T23:59:59.000Z

383

Thermal ignition combustion system  

SciTech Connect (OSTI)

A thermal ignition combustion system adapted for use with an internal combustion engine is described comprising: (a) means for providing ignition chamber walls defining an ignition chamber, the chamber walls being made of a material having a thermal conductivity greater than 20 W/m/sup 0/C. and a specific heat greater than 480J/kg/sup 0/C., the ignition chamber being in constant communication with the main combustion chamber; (b) means for maintaining the temperature of the chamber walls above a threshold temperature capable of causing ignition of a fuel; and (c) means for conducting fuel to the ignition chamber.

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

1988-04-19T23:59:59.000Z

384

Water transport inside a single-walled carbon nanotube driven by temperature gradient  

E-Print Network [OSTI]

Water transport inside a single-walled carbon nanotube driven by temperature gradient J. Shiomi mass transport of a water cluster inside a single-walled carbon nanotube (SWNT) with the diameter of about 1.4 nm. The influence of the non-equilibrium thermal environment on the confined water cluster has

Maruyama, Shigeo

385

Thermal Transport in Nanoporous Materials for Energy Applications  

E-Print Network [OSTI]

Theory of thermal conduction in thin ceramic ?lms”,Thermal resistance of grain boundaries in alumina ceramicsThermal conduc- tivity of highly porous zirconia”, Journal of the European Ceramic

Fang, Jin

2012-01-01T23:59:59.000Z

386

Thermal emission of neutron stars with internal heaters  

Science Journals Connector (OSTI)

......our consideration of thermal coupling/decoupling...dependence of redshifted thermal heat-conduction flux...star (in units of solar luminosity Lo) for...sufficiently long time to overheat the crust and violate the thermal balance of the crust......

A. D. Kaminker; A. A. Kaurov; A. Y. Potekhin; D. G. Yakovlev

2014-01-01T23:59:59.000Z

387

Optimization of synchronization in gradient clustered networks  

E-Print Network [OSTI]

We consider complex clustered networks with a gradient structure, where sizes of the clusters are distributed unevenly. Such networks describe more closely actual networks in biophysical systems and in technological applications than previous models. Theoretical analysis predicts that the network synchronizability can be optimized by the strength of the gradient field but only when the gradient field points from large to small clusters. A remarkable finding is that, if the gradient field is sufficiently strong, synchronizability of the network is mainly determined by the properties of the subnetworks in the two largest clusters. These results are verified by numerical eigenvalue analysis and by direct simulation of synchronization dynamics on coupled-oscillator networks.

Xingang Wang; Liang Huang; Ying-Cheng Lai; Choy Heng Lai

2007-11-23T23:59:59.000Z

388

Optimization Online - An Accelerated Proximal Coordinate Gradient ...  

E-Print Network [OSTI]

Jul 7, 2014 ... An Accelerated Proximal Coordinate Gradient Method and its Application to Regularized Empirical Risk Minimization. Qihang Lin(qihang-lin ...

Qihang Lin

2014-07-07T23:59:59.000Z

389

Influence of embedded-carbon nanotubes on the thermal properties of copper matrix nanocomposites processed  

E-Print Network [OSTI]

-level mix- ing, exhibits CNTs homogeneously dispersed in the Cu matrix. Measured thermal conductivity: Metal matrix composites; Nanocomposite; Carbon and graphite; Thermal conductivity Carbon nanotubes (CNTs management applications, due to their extraordinarily low coefficient of thermal expan- sion (CTE) [1

Hong, Soon Hyung

390

Student Affairs STUDENT CONDUCT  

E-Print Network [OSTI]

Student Affairs CODE OF STUDENT CONDUCT 2014-15 #12;Contents Letter from the Dean of Students ....................................................................ii Binghamton University's Code of Student Conduct Preamble...................... 1 Section I: Rules of Student Conduct.............................................................. 1 Section II: Definitions

Suzuki, Masatsugu

391

Vapor deposited samarium zirconate thermal barrier coatings Hengbei Zhao a,  

E-Print Network [OSTI]

Thermal barrier coatings The rare earth zirconates (M2Zr2O7, M=LaGd) have a low intrinsic thermal conductivity and high temperature phase stability making them attractive candidates for thermal barrier coating conditions and the coating composition, structure, texture, pore morphology, and thermal conductivity

Wadley, Haydn

392

Scrape-off Layer Flows With Pressure Gradient Scale Length ~ {rho}{sub p}  

SciTech Connect (OSTI)

A heuristic model for the plasma scrape-off width balances magnetic drifts against parallel loss at c{sub s} /2, resulting in a SOL width ~ {rho}{sub p}. T{sub sep} is calculated from Spitzer–Härm parallel thermal conduction. This results in a prediction for the power scrape-off width in quantitative agreement both in magnitude and scaling with recent experimental data. To achieve the ~ c{sub s} /2 flow assumed in this model and measured experimentally sets requirements on the ratio of upstream to total SOL particle sources, relative to the square-root of the ratio of target to upstream temperature. The Pfisch-Schlüter model for equilibrium flows has been modified to allow near-sonic flows, appropriate for gradient scale lengths of order {rho}{sub p}, resulting in a new quadrupole radial flow pattern. The strong parallel flows and plasma charging implied by this model suggest a mechanism for H-mode transition, consistent with many observations

Robert J. Goldston

2013-03-08T23:59:59.000Z

393

Thermal and Electrical Transport in Oxide Heterostructures  

E-Print Network [OSTI]

2.3.1 Electrical transport . . . . . . . . . . . . . . . .3.5 Controlling electrical conductivity and opticalthe variation of electrical and thermal con- ductivity and

Ravichandran, Jayakanth

2011-01-01T23:59:59.000Z

394

Microinstabilities in weak density gradient tokamak systems  

SciTech Connect (OSTI)

A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved (''H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Depsite this favorable trend, it is emphasized here that, even in the limit of zero density gradient, low-frequency microinstabilities can persist due to the nonzero temperature gradient.

Tang, W.M.; Rewoldt, G.; Chen, L.

1986-04-01T23:59:59.000Z

395

Chapter 5 Salinity Gradient Energy  

Science Journals Connector (OSTI)

There exists a huge potential for the generation of energy from the mixing of saltwater and freshwater. The potential is 2.6 TW, which is more than the global electricity consumption (2.0 TW). Two membrane-based technologies exist to convert this potentially available energy into useful power: pressure-retarded osmosis (PRO) and reverse electrodialysis (RED). In PRO, water is transported through a semipermeable membrane from the less concentrated solution toward the concentrated salt solution to generate power. In RED, salt ions are transported from the concentrated salt solution through ion exchange membranes toward the less concentrated solution to extract the energy. Both technologies were developed in the 1970s and 1980s and both regained interest lately due to recent developments in membrane technology and the need for sustainable energy processes. This chapter describes the potential of salinity gradient energy of both processes in detail, and an overview of the relevant literature on both technologies is presented. Furthermore, it summarizes the recent developments, pilot testing, scale-up, and future expectations of both technologies.

Kitty Nijmeijer; Sybrand Metz

2010-01-01T23:59:59.000Z

396

Thermal management of nanoelectronics  

E-Print Network [OSTI]

-state thermoelectric on- spot cooling, requiring efficient thermoelectric materials that can be integrated with the IC are further complicated by the fact that the material's ability to conduct heat deteriorates when at the packaging level but also at the nanoscale materials and device levels. THERMAL CHALLENGES AT NANOSCALE One

397

Thermal desorption for passive dosimeter  

E-Print Network [OSTI]

~ ~ ~ \\ ~ ~ ~ ~ Flare Tubes for Thermal Desorber . . . . . ~. . . . . . ~ ~ . 27 4. 5 ~ Thermal Desorber Manufactured by Century System Sample Flow from Thermal Desorber to Gas Chromatograph 29 6. Direct Injection Port for Therma1 Desorber . . . . . $2... the gas badges and. providing additional guidance in conducting the study. DEDICATZOil This thesis is cedicated to my parents and my wife, Unice, for their support during the last t', o years AHSTHACT ACKI;ODL DG~~. 'ITS D' DICATICI'. LIST OF TABL...

Liu, Wen-Chen

1981-01-01T23:59:59.000Z

398

Numerical Modeling of the Transient Thermal Interference of Vertical U-Tube Haet Exchangers  

E-Print Network [OSTI]

installation separation range. Non-homogenous media were modeled by varying backfill thermal conductivity. Maximum heat transfer was achieved with a fictitious backfill thermal conductivity of 1,000 W/m-K, while measured bentonite backfill conductivities were...

Muraya, Norman K.

399

Were Archaean continental geothermal gradients much steeper than today? (reply)  

Science Journals Connector (OSTI)

... -We did not intend to suggest that our gradients bore any relationship to near-surface geothermal gradients. It may have been clearer to have termed them average ... gradients. It may have been clearer to have termed them average geothermal gradients. Our purpose in quoting these gradients was simply to emphasise that the temperature ...

KEVIN BURKE; W. S. F. KIDD

1978-08-17T23:59:59.000Z

400

Thermomechanical measurements on thermal microactuators.  

SciTech Connect (OSTI)

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 for thermal microactuators were not available for a single microactuator design, a comprehensive suite of thermal and mechanical experimental data was taken and compiled for model validation purposes. Three thermal microactuator designs were selected and fabricated using the SUMMiT V{sup TM} process at Sandia National Laboratories. Thermal and mechanical measurements for the bent-beam polycrystalline silicon thermal microactuators are reported, including displacement, overall actuator electrical resistance, force, temperature profiles along microactuator legs in standard laboratory air pressures and reduced pressures down to 50 mTorr, resonant frequency, out-of-plane displacement, and dynamic displacement response to applied voltages.

Baker, Michael Sean; Epp, David S.; Serrano, Justin Raymond; Gorby, Allen D.; Phinney, Leslie Mary

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Applications of salinity gradient solar technologies in the Southwest -- An overview  

SciTech Connect (OSTI)

This paper is an overview of recent applications of salinity gradient solar technologies (SGST) in the Southwest and especially in the State of Texas. SGST is a generic title for using a salinity gradient in a body of water to suppress convection and collect solar energy for a desired application, for example, salinity gradient solar ponds. Following initial work in the early 1980s at the El Paso Solar Pond project and funding of the Texas Solar Pond Consortium by the State of Texas and the Bureau of Reclamation, several applications involving the use of salinity gradient solar technologies have emerged. These applications include a biomass waste to energy project using heat from a solar pond at Bruce Foods Corporation; an industrial process heat application for sodium sulfate mining near Seagraves, Texas; overwintering thermal refuges for mariculture in Palacios, Texas; a potential salt management project on the Brazos River near Abilene, Texas; and use of solar ponds for brine disposal at a water desalting project in a small colonia east of El Paso. This paper discusses salinity gradient solar technology requirements and the abundance of resources available in Texas and the Southwest which makes this an attractive location for the commercial development of salinity gradient projects. Barriers to development as well as catalysts are discussed before a brief overview of the projects listed above is provided.

Swift, A.H.P.; Lu, H. [Univ. of Texas, El Paso, TX (United States)

1996-12-31T23:59:59.000Z

402

Measurement of thermodynamics using gradient flow  

E-Print Network [OSTI]

We analyze bulk thermodynamics and correlation functions of the energy-momentum tensor in pure Yang-Mills gauge theory using the energy-momentum tensor defined by the gradient flow and small flow time expansion. Our results on thermodynamic observables are consistent with those obtained by the conventional integral method. The analysis of the correlation function of total energy supports the energy conservation. It is also addressed that these analyses with gradient flow require less statistics compared with the previous methods. All these results suggest that the energy-momentum tensor can be successfully defined and observed on the lattice with moderate numerical costs with the gradient flow.

Masakiyo Kitazawa; Masayuki Asakawa; Tetsuo Hatsuda; Takumi Iritani; Etsuko Itou; Hiroshi Suzuki

2014-12-15T23:59:59.000Z

403

Thermal creation of electron spin polarization in n-type silicon  

SciTech Connect (OSTI)

Conversion of heat into a spin-current in electron doped silicon can offer a promising path for spin-caloritronics. Here, we create an electron spin polarization in the conduction band of n-type silicon by producing a temperature gradient across a ferromagnetic tunnel contact. The substrate heating experiments induce a large spin signal of 95??V, corresponding to 0.54?meV spin-splitting in the conduction band of n-type silicon by Seebeck spin tunneling mechanism. The thermal origin of the spin injection has been confirmed by the quadratic scaling of the spin signal with the Joule heating current and linear dependence with the heating power.

Dankert, André, E-mail: andre.dankert@chalmers.se; Dash, Saroj P., E-mail: saroj.dash@chalmers.se [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden)

2013-12-09T23:59:59.000Z

404

Thermal Creation of Electron Spin Polarization in n-Type Silicon  

E-Print Network [OSTI]

Conversion of heat into a spin-current in electron doped silicon can offer a promising path for spin-caloritronics. Here we create an electron spin polarization in the conduction band of n-type silicon by producing a temperature gradient across a ferromagnetic tunnel contact. The substrate heating experiments induce a large spin signal of 95 $\\mu$V, corresponding to 0.54 meV spin-splitting in the conduction band of n-type silicon by Seebeck spin tunneling mechanism. The thermal origin of the spin injection has been confirmed by the quadratic scaling of the spin signal with the Joule heating current and linear dependence with the heating power.

André Dankert; Saroj P. Dash

2014-03-14T23:59:59.000Z

405

Code of Conduct  

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

Governance » Governance » Ethics, Accountability » Code of Conduct Code of Conduct Helping employees recognize and resolve the ethics and compliance issues that may arise in their daily work. Contact Code of Conduct (505) 667-7506 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 work, and mutual respect and teamwork. LANL must demonstrate to customers and the public that the Laboratory is accountable for its actions and that it conducts business in a trustworthy manner. What is LANL's Code of Conduct? Charlie McMillan 1:46 Laboratory Director Charlie McMillan introduces the code LANL's Code of Conduct is designed to help employees recognize and

406

JLF Conduct of Operations  

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

Jupiter Laser Facility (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...

407

1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations  

E-Print Network [OSTI]

The thermal conductivity of nanostructures generally decreases with decreasing size because of classical size effects. The axial thermal conductivity of polymer chain lattices, however, can exhibit the opposite trend, ...

Henry, Asegun

408

Ballistic dispersion in temperature gradient focusing  

E-Print Network [OSTI]

regime is the most familiar regime in microfluidic systems, an oft-overlooked regime is that of purely kinematic (or ballistic) dispersion. In most microfluidic systems, this dispersion regime is transient systems. Keywords: microfluidics; temperature gradient focusing; kinematic dispersion; Taylor

Santiago, Juan G.

409

Separation of carbon nanotubes in density gradients  

DOE Patents [OSTI]

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.

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

2012-02-07T23:59:59.000Z

410

Separation of carbon nanotubes in density gradients  

DOE Patents [OSTI]

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.

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

2010-02-16T23:59:59.000Z

411

The proximal-proximal gradient algorithm  

E-Print Network [OSTI]

Aug 23, 2013 ... to consider a proximal gradient algorithm [11] for solving (1), where one ...... Hence, in the case when ? = 1 and M is surjective so that T = MR for ...

2013-08-24T23:59:59.000Z

412

Program predicts two-phase pressure gradients  

SciTech Connect (OSTI)

The calculator program discussed, ORK, was designed for the HP-41CV hand-held calculator and uses the Orkiszewski correlation for predicting 2-phase pressure gradients in vertical tubulars. Accurate predictions of pressure gradients in flowing and gas lift wells over a wide range of well conditions can be obtained with this method, which was developed based on data from 148 wells. The correlation is one of the best generalized 2-phase pressure gradient prediction methods developed to date for vertical flow. It is unique in that hold-up is derived from observed physical phenomena, and the pressure gradient is related to the geometrical distribution of the liquid and gas phase (flow regime).

Jacks, D.C.; Hill, A.D.

1983-11-18T23:59:59.000Z

413

Ab initio calculation of the temperature dependence of the electric field gradient in Be  

Science Journals Connector (OSTI)

Using the orthogonalized-plane-wave procedure, the band structure, Fermi surface, and conduction-electron wave functions of Be have been calculated as a function of temperature. The electric field gradients calculated from first principles obey the T32 behavior and are negative throughout the temperature range studied.

P. Jena and J. Rath

1981-04-15T23:59:59.000Z

414

Electrically conductive composite material  

DOE Patents [OSTI]

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.

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

1989-05-23T23:59:59.000Z

415

Heat conduction of single-walled carbon nanotube isotope-superlattice structures: A molecular dynamics study  

E-Print Network [OSTI]

-folding effect to thermal boundary resistance of lattice interface. The crossover mechanism is explained-dimensional materials. In our previous molecular dynamics study, isotope-effects on the thermal conduction were of heat conduction of SWNTs subjected to nanoscale intrinsic thermal resistances. Here, in order to reduce

Maruyama, Shigeo

416

CONDUCT OF OPERATIONS (CO)  

Broader source: Energy.gov (indexed) [DOE]

CONDUCT OF OPERATIONS (CO) CONDUCT OF OPERATIONS (CO) OBJECTIVE TA-55 SST Facility NNSA ORR Implementation Plan 1 1 CO.1 The formality and discipline of operations is adequate to conduct work safely and programs are inplace to maintain this formality and discipline. (Core Requirement 13) Criteria 1. Programmatic elements of conduct of operations are in place for TA-55 SST operations. 2. The TA-55 SST operations personnel adequately demonstrate the principles of conduct ofoperations requirements during the shift performance period. Approach Record Reviews: Review procedures and other facility documents to verify compliance with conduct of operations principles. Interviews: Interview a sampling of the TA-55 SST associated personnel to validate their understanding of the conduct of operations principles (e.g., procedure usage,

417

Shallow Drilling In The Salton Sea Region, The Thermal Anomaly  

SciTech Connect (OSTI)

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.

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

1987-01-01T23:59:59.000Z

418

Nanoscale thermal transport. II. 2003–2012  

SciTech Connect (OSTI)

A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of the field. Interfaces become increasingly important on small length scales. Research during the past decade has extended studies of interfaces between simple metals and inorganic crystals to interfaces with molecular materials and liquids with systematic control of interface chemistry and physics. At separations on the order of ?1?nm, the science of radiative transport through nanoscale gaps overlaps with thermal conduction by the coupling of electronic and vibrational excitations across weakly bonded or rough interfaces between materials. Major advances in the physics of phonons include first principles calculation of the phonon lifetimes of simple crystals and application of the predicted scattering rates in parameter-free calculations of the thermal conductivity. Progress in the control of thermal transport at the nanoscale is critical to continued advances in the density of information that can be stored in phase change memory devices and new generations of magnetic storage that will use highly localized heat sources to reduce the coercivity of magnetic media. Ultralow thermal conductivity—thermal conductivity below the conventionally predicted minimum thermal conductivity—has been observed in nanolaminates and disordered crystals with strong anisotropy. Advances in metrology by time-domain thermoreflectance have made measurements of the thermal conductivity of a thin layer with micron-scale spatial resolution relatively routine. Scanning thermal microscopy and thermal analysis using proximal probes has achieved spatial resolution of 10?nm, temperature precision of 50 mK, sensitivity to heat flows of 10 pW, and the capability for thermal analysis of sub-femtogram samples.

Cahill, David G., E-mail: d-cahill@illinois.edu; Braun, Paul V. [Department of Materials Science and Engineering and the Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States); Chen, Gang [Department of Mechanical Engineering, MIT, Cambridge, Massachusetts 02139 (United States); Clarke, David R. [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Fan, Shanhui [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Goodson, Kenneth E. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Keblinski, Pawel [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); King, William P. [Department of Mechanical Sciences and Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Mahan, Gerald D. [Department of Physics, Penn State University, University Park, Pennsylvania 16802 (United States); Majumdar, Arun [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Maris, Humphrey J. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Phillpot, Simon R. [Department of Materials Science and Engineering, University of Florida, Gainseville, Florida 32611 (United States); Pop, Eric [Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Shi, Li [Department of Mechanical Engineering, University of Texas, Autin, Texas 78712 (United States)

2014-03-15T23:59:59.000Z

419

Scattering polarization in the CaII Infrared Triplet with Velocity Gradients  

E-Print Network [OSTI]

Magnetic field topology, thermal structure and plasma motions are the three main factors affecting the polarization signals used to understand our star. In this theoretical investigation, we focus on the effect that gradients in the macroscopic vertical velocity field have on the non-magnetic scattering polarization signals, establishing the basis for general cases. We demonstrate that the solar plasma velocity gradients have a significant effect on the linear polarization produced by scattering in chromospheric spectral lines. In particular, we show the impact of velocity gradients on the anisotropy of the radiation field and on the ensuing fractional alignment of the CaII levels, and how they can lead to an enhancement of the zero-field linear polarization signals. This investigation remarks the importance of knowing the dynamical state of the solar atmosphere in order to correctly interpret spectropolarimetric measurements, which is important, among other things, for establishing a suitable zero field refe...

Carlin, E S; Ramos, A Asensio; Bueno, J Trujillo

2012-01-01T23:59:59.000Z

420

Salinity gradient solar pond technology applied to potash solution mining  

SciTech Connect (OSTI)

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.

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

2000-06-12T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Acoustical power amplification and damping by temperature gradients  

Science Journals Connector (OSTI)

Ceperley proposed a concept of a traveling wave heat engine [“A pistonless Stirling engine—The traveling wave heat engine ” J. Acoust. Soc. Am. 66 1508–1513 (1979).] that provided a starting point of thermoacoustics today. This paper verifies experimentally his idea through observation of amplification and strong damping of a plane acoustic traveling wave as it passes through axial temperature gradients. The acoustic power gain is shown to obey a universal curve specified by a dimensionless parameter ???; ? is the angular frequency and ?? is the relaxation time for the gas to thermally equilibrate with channel walls. As an application of his idea a three-stage acoustic power amplifier is developed which attains the gain up to 10 with a moderate temperature ratio of 2.3.

Tetsushi Biwa; Ryo Komatsu; Taichi Yazaki

2011-01-01T23:59:59.000Z

422

Acoustic phonon engineering of thermal properties of silicon-based nanostructures  

E-Print Network [OSTI]

with the high electrical conductivity and low thermal conductivity [7]. It has been shown theoretically investigate the influence of the cladding materials on the phonon thermal conductivity in Si-based planar thermal conduction in the Si-based planar heterostructures and rectangular hetero-nanowires. The phonon

423

A Detailed Thermal Analysis of the Binospec Spectrograph  

E-Print Network [OSTI]

Refractive optics in astronomical instruments are potentially sensitive to temperature gradients and temperature transients. This sensitivity arises from thermally dependent refractive indices, lens spacings, and lens dimensions. We have therefore undertaken a detailed thermal analysis of Binospec, a wide-field optical spectrograph under development for the converted MMT. Our goals are to predict the temperature gradients that will be present in the Binospec optics and structure under realistic operating conditions and to determine how design choices affect these gradients. We begin our analysis by deriving thermal time constants for instrument subassemblies. We then generate a low-resolution finite difference model of the entire instrument and high-resolution models of sensitive subassemblies. This approach to thermal analysis is applicable to a variety of other instruments. We use measurements of the ambient temperature in the converted MMT's dome to model Binospec's thermal environment. During moderate conditions we find that the Binospec lens groups develop 0.14 C axial and radial temperature gradients and that lens groups of different mass develop 0.5 C temperature differences; these numbers are doubled for the extreme conditions. Internal heat sources do not significantly affect these results; heat flow from the environment dominates. The instrument must be periodically opened to insert new aperture masks, but we find that the resulting temperature gradients and thermal stresses in the optics are small. Image shifts at the detector caused by thermal deflections of the Binospec optical bench structure are approx 0.1 pixel/hr. We conclude that the proposed Binospec design has acceptable thermal properties, and briefly discuss design changes to further reduce temperature gradients.

Warren R. Brown; Daniel G. Fabricant; David A. Boyd

2002-10-28T23:59:59.000Z

424

High conductance surge cable  

DOE Patents [OSTI]

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.

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

1998-12-08T23:59:59.000Z

425

High conductance surge cable  

DOE Patents [OSTI]

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.

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

1998-01-01T23:59:59.000Z

426

Lattice Boltzmann approach to thermal transpiration  

SciTech Connect (OSTI)

Diffuse reflection boundary conditions are introduced in a thermal lattice Boltzmann model to allow for variable fluid density and temperature along the walls. The capability of this model to capture the main characteristics of the thermal transpiration phenomenon in a box at nonvanishing Knudsen numbers is demonstrated. The thermal creep velocity is found to be proportional to the temperature gradient imposed at the wall, whereas the accuracy of the simulation results are found to be of first or second order, depending on the numerical scheme.

Sofonea, Victor [Center for Fundamental and Advanced Technical Research, Romanian Academy, Bd. Mihai Viteazul 24, RO - 300223 Timisoara (Romania)

2006-11-15T23:59:59.000Z

427

Lattice Boltzmann model for thermal transpiration  

Science Journals Connector (OSTI)

The conventional Navier-Stokes-Fourier equations with no-slip boundary conditions are unable to capture the phenomenon of gas thermal transpiration. While kinetic approaches such as the direct simulation Monte Carlo method and direct solution of the Boltzmann equation can predict thermal transpiration, these methods are often beyond the reach of current computer technology, especially for complex three-dimensional flows. We present a computationally efficient nonequilibrium thermal lattice Boltzmann model for simulating temperature-gradient-induced flows. The good agreement between our model and kinetic approaches demonstrates the capabilities of the proposed lattice Boltzmann method.

G. H. Tang; Y. H. Zhang; X. J. Gu; R. W. Barber; D. R. Emerson

2009-02-12T23:59:59.000Z

428

Lattice Boltzmann approach to thermal transpiration  

Science Journals Connector (OSTI)

Diffuse reflection boundary conditions are introduced in a thermal lattice Boltzmann model to allow for variable fluid density and temperature along the walls. The capability of this model to capture the main characteristics of the thermal transpiration phenomenon in a box at nonvanishing Knudsen numbers is demonstrated. The thermal creep velocity is found to be proportional to the temperature gradient imposed at the wall, whereas the accuracy of the simulation results are found to be of first or second order, depending on the numerical scheme.

Victor Sofonea

2006-11-16T23:59:59.000Z

429

Research Conduct Policies  

Office of Science (SC) Website

Research Conduct Policies Basic Energy Sciences (BES) BES Home About Research Materials Sciences & Engineering (MSE) Chemical Sciences, Geosciences, and Biosciences (CSGB)...

430

Transient hydrodynamic, heat and mass transfer in a salinity gradient solar pond: A numerical study  

Science Journals Connector (OSTI)

Abstract The impoverishment of our planet in non-renewable energies has incited researchers to design salinity gradient solar ponds to collect and store solar energy at a lower cost. It is in this context that the present research work lies to focus on the numerical study of the transient hydrodynamic, heat and mass transfer in a salinity gradient solar pond. The problem is tackled using the dimensionless governing equations of Navier–Stokes, thermal energy and mass transfer, which are solved numerically by finite-volume method to provide the temperature, concentration and velocity fields in transient regime. The pond is filled with salty water of various salinities to form three zones of salty water: Upper Convective Zone (UCZ), Non-Convective Zone (NCZ) and Lower Convective Zone (LCZ). To prevent convective movements induced by the internal heating of salty water due to solar radiation absorption, a salinity gradient is used in the solar pond. Representative results illustrating the influence of internal Rayleigh number on the thermal performance of the pond and the effect of the aspect ratio on the distribution of temperature and velocity fields in the salinity gradient solar pond (SGSP) are discussed. In addition, results for the transient average temperature of UCZ and LCZ are presented and discussed for various parametric conditions.

Ridha Boudhiaf; Mounir Baccar

2014-01-01T23:59:59.000Z

431

Thermal and non-thermal energies in solar flares  

E-Print Network [OSTI]

The energy of the thermal flare plasma and the kinetic energy of the non-thermal electrons in 14 hard X-ray peaks from 9 medium-sized solar flares have been determined from RHESSI observations. The emissions have been carefully separated in the spectrum. The turnover or cutoff in the low-energy distribution of electrons has been studied by simulation and fitting, yielding a reliable lower limit to the non-thermal energy. It remains the largest contribution to the error budget. Other effects, such as albedo, non-uniform target ionization, hot target, and cross-sections on the spectrum have been studied. The errors of the thermal energy are about equally as large. They are due to the estimate of the flare volume, the assumption of the filling factor, and energy losses. Within a flare, the non-thermal/thermal ratio increases with accumulation time, as expected from loss of thermal energy due to radiative cooling or heat conduction. Our analysis suggests that the thermal and non-thermal energies are of the same magnitude. This surprising result may be interpreted by an efficient conversion of non-thermal energy to hot flare plasma.

Pascal Saint-Hilaire; Arnold O. Benz

2005-03-03T23:59:59.000Z

432

Thermally actuated thermionic switch  

DOE Patents [OSTI]

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.

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

1982-09-30T23:59:59.000Z

433

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber-Reinforced Ceramic Composite  

E-Print Network [OSTI]

when the material is subjected to temperature gradients and is therefore relevant to its thermal shock resistance. The present study focuses on the effects of a periodic array of matrix cracks on thermal displacement are used to determine the contributions to the longitudinal thermal resistance due to each crack

Zok, Frank

434

The long range migration of hydrogen through Zircaloy in response to tensile and compressive stress gradients  

SciTech Connect (OSTI)

Zircaloy-4, which is used widely as a core structural material in pressurized water reactors (PWRs), picks up hydrogen during service. Hydrogen solubility in Zircaloy-4 is low and zirconium hydride phases precipitate after the Zircaloy-4 lattice becomes supersaturated with hydrogen. These hydrides embrittle the Zircaloy-4, degrading its mechanical performance as a structural material. Because hydrogen can move rapidly through the Zircaloy-4 lattice, the potential exists for large concentrations of hydride to accumulate in local regions of a Zircaloy component remote from its point of entry into the component. Much has been reported in the literature regarding the long range migration of hydrogen through Zircaloy under concentration gradients and temperature gradients. Relatively little has been reported, however, regarding the long range migration of hydrogen under stress gradients. This paper presents experimental results regarding the long range migration of hydrogen through Zircaloy in response to both tensile and compressive stress gradients. The importance of this driving force for hydrogen migration relative to concentration and thermal gradients is discussed.

Kammenzind, B.F.; Berquist, B.M.; Bajaj, R.; Kreyns, P.H.; Franklin, D.G.

1998-11-01T23:59:59.000Z

435

Formation of morphogen gradients: Local accumulation time  

Science Journals Connector (OSTI)

Spatial regulation of cell differentiation in embryos can be provided by morphogen gradients, which are defined as the concentration fields of molecules that control gene expression. For example, a cell can use its surface receptors to measure the local concentration of an extracellular ligand and convert this information into a corresponding change in its transcriptional state. We characterize the time needed to establish a steady-state gradient in problems with diffusion and degradation of locally produced chemical signals. A relaxation function is introduced to describe how the morphogen concentration profile approaches its steady state. This function is used to obtain a local accumulation time that provides a time scale that characterizes relaxation to steady state at an arbitrary position within the patterned field. To illustrate the approach we derive local accumulation times for a number of commonly used models of morphogen gradient formation.

Alexander M. Berezhkovskii; Christine Sample; Stanislav Y. Shvartsman

2011-05-06T23:59:59.000Z

436

Measurement of Thermal Dependencies of PBG Fiber Properties  

SciTech Connect (OSTI)

Photonic crystal fibers (PCFs) represent a class of optical fibers which have a wide spectrum of applications in the telecom and sensing industries. Currently, the Advanced Accelerator Research Department at SLAC is developing photonic bandgap particle accelerators, which are photonic crystal structures with a central defect used to accelerate electrons and achieve high longitudinal electric fields. Extremely compact and less costly than the traditional accelerators, these structures can support higher accelerating gradients and will open a new era in high energy physics as well as other fields of science. Based on direct laser acceleration in dielectric materials, the so called photonic band gap accelerators will benefit from mature laser and semiconductor industries. One of the key elements to direct laser acceleration in hollow core PCFs, is maintaining thermal and structural stability. Previous simulations demonstrate that accelerating modes are sensitive to the geometry of the defect region and the variations in the effective index. Unlike the telecom modes (for which over 95% of the energy propagates in the hollow core) most of the power of these modes is located in the glass at the periphery of the central hole which has a higher thermal constant than air ({gamma}{sub SiO{sub 2}} = 1.19 x 10{sup -6} 1/K, {gamma}{sub air} = -9 x 10{sup -7} 1/K with {gamma} = dn/dT). To fully control laser driven acceleration, we need to evaluate the thermal and structural consequences of such modes on the PCFs. We are conducting series of interferometric tests to quantify the dependencies of the HC-633-02 (NKT Photonics) propagation constant (k{sub z}) on temperature, vibration amplitude, stress and electric field strength. In this paper we will present the theoretical principles characterizing the thermal behavior of a PCF, the measurements realized for the fundamental telecom mode (TE{sub 00}), and the experimental demonstration of TM-like mode propagation in the HC-633-02 fiber.

Laouar, Rachik

2011-07-06T23:59:59.000Z

437

High-pressure liquid chromatographic gradient mixer  

DOE Patents [OSTI]

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.

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

1982-09-08T23:59:59.000Z

438

24-26 September 2008, Rome, Italy Thermal Design of  

E-Print Network [OSTI]

conductivity of most materials used to electrically insulate the devices enhances the thermal issues that could to estimate the overall thermal resistance by considering a combination of individual thermal resistances of layout parameters upon the thermal resistance of such devices. This contribution is aimed at supplying

Technische Universiteit Delft

439

THERMAL PROPERTIES OF SINGLE-WALLED CARBON NANOTUBES Shigeo MARUYAMA  

E-Print Network [OSTI]

, optical and mechanical properties, thermal properties of SWNTs are quite unique with the high thermal and thermal conductance between a nanotube and various materials are reviewed. The experimental approach, and thermal boundary resistance in a junction of nanotubes are reviewed. Then, the heat transfer from an SWNT

Maruyama, Shigeo

440

Thermal and non-thermal energies in solar flares  

E-Print Network [OSTI]

The energy of the thermal flare plasma and the kinetic energy of the non-thermal electrons in 14 hard X-ray peaks from 9 medium-sized solar flares have been determined from RHESSI observations. The emissions have been carefully separated in the spectrum. The turnover or cutoff in the low-energy distribution of electrons has been studied by simulation and fitting, yielding a reliable lower limit to the non-thermal energy. It remains the largest contribution to the error budget. Other effects, such as albedo, non-uniform target ionization, hot target, and cross-sections on the spectrum have been studied. The errors of the thermal energy are about equally as large. They are due to the estimate of the flare volume, the assumption of the filling factor, and energy losses. Within a flare, the non-thermal/thermal ratio increases with accumulation time, as expected from loss of thermal energy due to radiative cooling or heat conduction. Our analysis suggests that the thermal and non-thermal energies are of the same m...

Saint-Hilaire, P; Saint-Hilaire, Pascal; Benz, Arnold O.

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Thermal to electricity conversion using thermal magnetic properties  

DOE Patents [OSTI]

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.

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

2010-04-27T23:59:59.000Z

442

Photopolymerization in Microfluidic Gradient Generators: Microscale  

E-Print Network [OSTI]

-compliance profiles that are tunable on the micro- scale. The most straightforward way to create substrates with vari through the development of microfluidic networks,[7,8] with which one can easily generate solution (e microscale gradients with microfluidic networks, and a recent study that demon- strated

443

Porting the NAS-NPB Conjugate Gradient  

E-Print Network [OSTI]

Porting the NAS-NPB Conjugate Gradient Benchmark to CUDA NVIDIA Corporation #12;Outline ! Overview of CG benchmark ! Overview of CUDA Libraries ! CUSPARSE ! CUBLAS ! Porting Sequence ! Algorithm Analysis ! Data/Code Analysis This porting approach uses CUDA Libraries exclusively. (We will not write

Crawford, T. Daniel

444

Fourier Accelerated Conjugate Gradient Lattice Gauge Fixing  

E-Print Network [OSTI]

We provide details of the first implementation of a non-linear conjugate gradient method for Landau and Coulomb gauge fixing with Fourier acceleration. We find clear improvement over the Fourier accelerated steepest descent method, with the average time taken for the algorithm to converge to a fixed, high accuracy, being reduced by a factor of 2 to 4.

R. J. Hudspith

2014-05-22T23:59:59.000Z

445

Electrically conductive material  

DOE Patents [OSTI]

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.

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

1993-01-01T23:59:59.000Z

446

Electrically conductive material  

DOE Patents [OSTI]

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.

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

1993-09-07T23:59:59.000Z

447

Gradient zone-boundary control in salt-gradient solar ponds  

DOE Patents [OSTI]

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.

Hull, J.R.

1982-09-29T23:59:59.000Z

448

E-Print Network 3.0 - anomalous heat conduction Sample Search...  

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

University, Stanford, California, January 31 -February 2, 2011 Summary: conductive heat loss outside the main areas of thermally anomalous ground, and nor have discharges...

449

Thermal treatment  

Science Journals Connector (OSTI)

Thermal treatment can be regarded as either a pre-treatment of waste prior to final disposal, or as a means of valorising waste by recovering energy. It includes both the burning of mixed MSW in municipal inciner...

Dr. P. White; Dr. M. Franke; P. Hindle

1995-01-01T23:59:59.000Z

450

Thermal Processes  

Broader source: Energy.gov [DOE]

Some thermal processes use the energy in various resources, such as natural gas, coal, or biomass, to release hydrogen, which is part of their molecular structure. In other processes, heat, in...

451

Measurement and modeling thermal conductivity of baked products  

E-Print Network [OSTI]

the intercept with the y-sxis (dp) and the error term (e), and adds variables one at a time until a. stopping criterion is satisfied, 0. 1 6 Q 0. 14 8 3 0. 12 g 0. 10 O V 0. 08 0. 06 + + + +y++++ ++ ~ +est~ ~ 4. + ~ c ~ + ~ f ~f, ?, , ey ~ ~ p... FOR DEPENDENT VARIABLE K STATISTICS FOR ENTRY: STEP 1 DF 1. 80 MODEL VARIABLE TOLERANCE R* 2 F PROB&F W 0 POR 1 0. 0373 3. 0995 1 0. 2539 27. 2194 1 0. 0099 0. 8006 0. 0821 0. 0001 0. 3736 STEP 1 VARIABLE D ENTERED R SQUARE = 0. 25386619 C(P) = 2...

Islas Rubio, Alma Rosa

2012-06-07T23:59:59.000Z

452

THERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND  

E-Print Network [OSTI]

. 1 Introduction In a context of sustainable development, green buildings aim at reducing, raw material, #12;water...) and to emissions (greenhouse gas, pollution, wastes...). Thus, green buildings should be energy efficient while showing a light foot-print on the environment over the entire

453

Thermal conduction and multiphase gas in cluster cores  

Science Journals Connector (OSTI)

......NNX10AC95G, Chandra theory grant TM2-13004X and the Thomas and Alison Schneider Chair in Physics at UC Berkeley. REFERENCES Antolin...769:L22. Birzan L. , Rafferty D. A., McNamara B. R., Wise M. W., Nulsen P. E. J. ApJ (2004) 607:800. Carilli......

Baban Wagh; Prateek Sharma; Michael McCourt

2014-01-01T23:59:59.000Z

454

THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS  

Office of Scientific and Technical Information (OSTI)

aqueous electrolyte solutions are required in the development and uti1 ization of geothermal energy, petroleum recovery, desalination of sea water, and other energy systems...

455

Molecular dynamics simulation of thermal conductivity of nanocrystalline composite films  

E-Print Network [OSTI]

October 2008 Available online 30 December 2008 a b s t r a c t The efficiency of a thermoelectric material that result in significant improvements in thermoelectric performance [1]. In particular, these materials show material, then the thermoelectric performance will increase by a factor of 2 over that of the homogeneous

Walker, D. Greg

456

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

457

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...

458

Thermal conductivity and specific heat of sorghum grain  

E-Print Network [OSTI]

Formation of Test Canister Ice Jacket ~ Sealing Test Canister in Calorimeter. . 43 44 Testing of Samples. Initial Calorimeter Observations. 49 Insertion of Grain Samples into Calorimeter. . . . 50 Final Test Observations Processing of Data. 54... to Contain the Grain Sample 38 for the Determination of Specific Heat 39 12. Top View of Calorimeter. 40 13. Galvanized Iron Cylinder Used to Form the Ice Jacket Around the Test Canister 42 VIII Figures 14. Clamping Device Used to Hold Test Canister...

Miller, Clinton Frank

2012-06-07T23:59:59.000Z

459

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...

460

Thermal contact conductance of a paper handsheet/metal interface  

E-Print Network [OSTI]

, , 1980' . 12 4 The influence of the tension of paper on intensity of paper drying [Tar- nawski and Kepaczka, 1980] . 13 5 TAPPI T-250 standard handsheet machine 17 6 TAPPI standard handsheet machine 18 7 Deckle and Base 19 8 Schematic of contact... g- Paper Industries (TAPPI) standard sheet machine manufactured by Noram Quality Control and Research Equipment Limited was used to prepare handsheets and TAPPI procedure T-205 was followed in making handsheets. The equipment used in the process...

Ng, Kin Hung

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "gradients thermal conductivity" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films  

E-Print Network [OSTI]

wire, serving as both a thermometer and a line heat source,as both heater and thermometer, was patterned on (A) (B)Diff Amp B Diff Amp Heater/thermometer on the sample I + V -

Coquil, Thomas; Richman, Eric K.; Hutchinson, Neal J.; Tolbert, S H; Pilon, Laurent

2009-01-01T23:59:59.000Z

462

Electrical and Thermal Experimental Characterization and Modeling of Carbon Nanotube/Epoxy Composites  

E-Print Network [OSTI]

The present work investigates the effect of carbon nanotube (CNT) inclusions on the electrical and thermal conductivity of a thermoset epoxy resin. The characterization of electrical and thermal conductivity of CNT/epoxy composites is presented...

Gardea, Frank

2012-10-19T23:59:59.000Z

463

Geothermal Resource-Reservoir Investigations Based On Heat Flow And Thermal  

Open Energy Info (EERE)

Resource-Reservoir Investigations Based On Heat Flow And Thermal Resource-Reservoir Investigations Based On Heat Flow And Thermal Gradient Data For The United States Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Geothermal Resource-Reservoir Investigations Based On Heat Flow And Thermal Gradient Data For The United States Details Activities (2) Areas (2) Regions (0) Abstract: Several activities related to geothermal resources in the western United States are described in this report. A database of geothermal site-specific thermal gradient and heat flow results from individual exploration wells in the western US has been assembled. Extensive temperature gradient and heat flow exploration data from the active exploration of the 1970's and 1980's were collected, compiled, and synthesized, emphasizing previously unavailable company data. Examples of

464

Fusion product measurements of the local ion thermal diffusivity in the PLT tokamak  

SciTech Connect (OSTI)

Measurement of the gradient of the d-d fusion rate profile in an ohmic PLT plasma is used to deduce the gradient of the ion temperature and, thus, the local ion thermal diffusivity through an energy balance analysis. The inferred ion diffusivity is consistent with neoclassical theory.

Heidbrink, W.W.; Lovberg, J.; Strachan, J.D.; Bell, R.E.

1986-03-01T23:59:59.000Z

465

Three-dimensional thermal analysis of wirelessly powered light-emitting systems  

Science Journals Connector (OSTI)

...geometrical parameters and thermal conductivities of the...bio-implanted applications. thermal analysis|wireless...wireless power, instead of batteries, could bring additional...battery replacement and battery biocompatibility. Recently...bio-integrated applications. The thermal behaviour of such systems...

2012-01-01T23:59:59.000Z

466

CONDUCTING A RECORDS INVENTORY  

Broader source: Energy.gov (indexed) [DOE]

PROCEDURE FOR CONDUCTING A RECORDS INVENTORY 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 information for scheduling purposes; b. Prepare for conversion to other media or to identify the volume of classified and/or permanent records in your organization's custody; and c. Identify any existing shortcomings, deficiencies, or problems with

467

The Thermal Insulation Properties for Wall Material with Various Water Contents  

Science Journals Connector (OSTI)

The thermal conductivities of wall material were measured under various water contents to investigate the effect of water content on the thermal insulation properties. The results show that water contents have adverse impact to heat insulation of wall ... Keywords: the thermal conductivity, water contents, the thermal insulation properties

Zhang Chuancheng; Lu Haijun

2010-05-01T23:59:59.000Z

468

Research Program - Center for Solar and Thermal Energy Conversion  

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

below. Organic and Hybrid Systems for TE Improving Thermoelectric Efficiency via Low Thermal Boundary Conductance Heat dissipation in Atomic-Scale Junctions A General Strategy to...

469

Electron profile stiffness and critical gradient studies  

SciTech Connect (OSTI)

Electron profile stiffness was studied in DIII-D L-mode discharges by systematically varying the heat flux in a narrow region with electron cyclotron heating and measuring the local change produced in {nabla}T{sub e}. Electron stiffness was found to slowly increase with toroidal rotation velocity. A critical inverse temperature gradient scale length 1/L{sub C} {approx} 3 m{sup -1} was identified at {rho}=0.6 and found to be independent of rotation. Both the heat pulse diffusivity and the power balance diffusivity, the latter determined by integrating the measured dependence of the heat pulse diffusivity on -{nabla}T{sub e}, were fit reasonably well by a model containing a critical inverse temperature gradient scale length and varying linearly with 1/L{sub T} above the threshold.

DeBoo, J. C.; Petty, C. C.; Burrell, K. H.; Smith, S. P. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); White, A. E. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Doyle, E. J.; Hillesheim, J. C.; Rhodes, T. L.; Schmitz, L.; Wang, G.; Zeng, L. [University of California-Los Angeles, Los Angeles, California 90095-7099 (United States); Holland, C. [University of California-San Diego, La Jolla, California 92093-0417 (United States); McKee, G. R. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2012-08-15T23:59:59.000Z

470

Automated apparatus for producing gradient gels  

DOE Patents [OSTI]

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.

Anderson, Norman L. (Clarendon Hills, IL)

1986-01-01T23:59:59.000Z

471

The Argonne Zero Gradient Synchrotron (ZGS)  

Science Journals Connector (OSTI)

A 12.5 billion electron volt (BeV) particle accelerator the Zero Gradient Synchrotron was constructed and put into operation at the Argonne National Laboratory in August 1963. The ZGS will form the center for high energy physics research in the Midwestern part of this country. In this paper a brief description of the ZGS is given together with a discussion of the aims methods and equipment of experimental high energy physics research.

L. C. Teng

1964-01-01T23:59:59.000Z

472

27-301: Microstructure-Properties: I L8: Thermal Properties  

E-Print Network [OSTI]

ionically and covalently bonded materials exhibit very low conductivities (electrical and thermal of materials to their microstructure. · A practical example is used of optimization of thermal conductivity mechanisms in different types of materials. · Metals exhibit high electrical and thermal conductivity

Rollett, Anthony D.

473

PUBLISHED ONLINE: 9 MAY 2010 | DOI: 10.1038/NMAT2753 Dimensional crossover of thermal transport in  

E-Print Network [OSTI]

on heat conduction in low-dimensional materials and may open up FLG applications in thermal management , is heat conduction in low- dimensional materials. The question of what happens with thermal conductivity unique electronic2,3 and optical properties4 , reveals unusually high thermal conductivity5,6 . The fact

474

Lithium ion conducting electrolytes  

DOE Patents [OSTI]

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.

Angell, C.A.; Liu, C.

1996-04-09T23:59:59.000Z

475

Conduct of Operations  

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

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 2, dated 12-3-14, cancels Admin Chg 1.

2010-06-29T23:59:59.000Z

476

The Boussinesq Problem in Dipolar Gradient Elasticity  

E-Print Network [OSTI]

The three-dimensional axisymmetric Boussinesq problem of an isotropic half-space subjected to a concentrated normal quasi-static load is studied within the framework of linear dipolar gradient elasticity. Our main concern is to determine possible deviations from the predictions of classical linear elastostatics when a more refined theory is employed to attack the problem. Of special importance is the behavior of the new solution near to the point of application of the load where pathological singularities exist in the classical solution. The use of the theory of gradient elasticity is intended here to model the response of materials with microstructure in a manner that the classical theory cannot afford. A linear version of this theory results by considering a linear isotropic expression for the strain-energy density that depends on strain-gradient terms, in addition to the standard strain terms appearing in classical elasticity. Through this formulation, a microstructural material constant is introduced, in addition to the standard Lam\\'e constants. The solution method is based on integral transforms and is exact. The present results show significant departure from the predictions of classical elasticity. Indeed, continuous and bounded displacements are predicted at the points of application of the concentrated load. Such a behavior of the displacement field is, of course, more natural than the singular behavior exhibited in the classical solution.

H. G. Georgiadis; P. A. Gourgiotis; D. S. Anagnostou

2014-03-31T23:59:59.000Z

477

FARADAYIC ElectroPhoretic Deposition of YSZ for Use in Thermal Barrier Coatings - Faraday Technology  

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

FARADAYIC ElectroPhoretic Deposition FARADAYIC ElectroPhoretic Deposition of YSZ for Use in Thermal Barrier Coatings-Faraday Technology Background Thermal barrier coatings (TBCs) are employed to protect gas turbine engine components. These coating systems provide thermal, oxidation, and mechanical protection; reduce thermal gradients; and lower the metal substrate surface temperature, extending the life of the engine components. Faraday Technology, Inc. (Faraday) is developing a new manufacturing process, the

478

Thermal Pretreatment For TRU Waste Sorting  

SciTech Connect (OSTI)

Japan Atomic Energy Agency conducted a study on thermal treatment of TRU waste to develop a removal technology for materials that are forbidden for disposal. The thermal pretreatment in which hot nitrogen and/or air is introduced to the waste is a process of removing combustibles, liquids, and low melting point metals from PVC wrapped TRU waste. In this study, thermal pretreatment of simulated waste was conducted using a desktop thermal treatment vessel and a laboratory scale thermal pretreatment system. Combustibles and low melting point metals are effectively separated from wastes by choosing appropriate temperature of flowing gases. Combustibles such as papers, PVC, oil, etc. were removed and low melting point metals such as zinc, lead, and aluminum were separated from the simulated waste by the thermal pretreatment. (authors)

Sasaki, T.; Aoyama, Y.; Miyamoto, Y.; Yamaguchi, H. [Japan Atomic Energy Agency, Tokai-mura, Ibaraki (Japan)

2008-07-01T23:59:59.000Z

479

Production of radioactivity in local soil at AGS (Alternating Gradient Synchrotron) fast neutrino beam  

SciTech Connect (OSTI)

Brookhaven National Laboratory (BNL) has constructed a new neutrino production target station at the Alternating Gradient Synchrotron (AGS). A study has been conducted in the vicinity of the old target area to determine the radiological consequences of operating this experimental facility. Results from all areas of the study are presented along with estimates of the potential environmental impact of the old and new facilities. 12 refs., 15 figs., 3 tabs.

Gollon, P.J.; Rohrig, N.; Hauptmann, M.G.; McIntyre, K.; Miltenberger, R.; Naidu, J.

1989-10-01T23:59:59.000Z

480

Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures  

SciTech Connect (OSTI)

The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

Byer, Robert L.

2013-11-07T23:59:59.000Z

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481

Gradient-based Methods for Production Optimization of Oil Reservoirs  

E-Print Network [OSTI]

Gradient-based Methods for Production Optimization of Oil Reservoirs Eka Suwartadi Doctoral Thesis oil reservoirs. Gradient- based optimization, which utilizes adjoint-based gradient computation optimization for water flooding in the secondary phase of oil recovery is the main topic in this thesis

Foss, Bjarne A.

482

Ceramic thermal barrier coating for rapid thermal cycling applications  

DOE Patents [OSTI]

A thermal barrier coating for metal articles subjected to rapid thermal cycling includes a metallic bond coat deposited on the metal article, at least one MCrAlY/ceramic layer deposited on the bond coat, and a ceramic top layer deposited on the MCrAlY/ceramic layer. The M in the MCrAlY material is Fe, Ni, Co, or a mixture of Ni and Co. The ceramic in the MCrAlY/ceramic layer is mullite or Al.sub.2 O.sub.3. The ceramic top layer includes a ceramic with a coefficient of thermal expansion less than about 5.4.times.10.sup.-6 .degree.C.sup.-1 and a thermal conductivity between about 1 J sec.sup.-1 m.sup.-1 .degree.C.sup.-1 and about 1.7 J sec.sup.-1 m.sup.-1 .degree.C.sup.-1.

Scharman, Alan J. (Hebron, CT); Yonushonis, Thomas M. (Columbus, IN)

1994-01-01T23:59:59.000Z

483

Low Temperature Proton Conductivity  

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

and and MEAs at Freezing Temperatures Thomas A. Zawodzinski, Jr. Case Western Reserve University Cleveland, Ohio 2 Freezing Fuel Cells: Impact on MEAS Below 0 o C *Transport processes/motions slow down: questions re: lower conductivity,water mobility etc *Residual water will have various physical effects in different portions of the MEA questions re: durability of components 3 3 'States' of Water in Proton Conductors ? Freezing (bulk), bound freezable, bound non freezable water states claimed based on DSC * Freezing water more mobile, allegedly important for high conductivity Analysis common for porous systems Does the presence of these states matter? Why? 4 'State of Water' in PEMs At T < 0 o C *'Liquid-like' water freezes *'Non-freezing' fraction: water of solvation at pore

484

Oxygen ion conducting materials  

DOE Patents [OSTI]

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.

Vaughey, John (Elmhurst, IL); Krumpelt, Michael (Naperville, IL); Wang, Xiaoping (Downers Grove, IL); Carter, J. David (Bolingbrook, IL)

2003-01-01T23:59:59.000Z

485

Super ionic conductive glass  

DOE Patents [OSTI]

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.

Susman, Sherman (Park Forest, IL); Volin, Kenneth J. (Fort Collins, CO)

1984-01-01T23:59:59.000Z

486

Lepidium latifolium reproductive potential and seed dispersal along salinity and moisture gradients  

E-Print Network [OSTI]

Preserve where the salinity gradient was narrow. Conversely,production along the salinity gradient between the freshdispersal along salinity and moisture gradients Samuel P.

Leininger, Samuel P.; Foin, Theodore C.

2009-01-01T23:59:59.000Z

487

Phonon Heat Conduction in Corrugated Silicon Nanowires Below the Casimir Limit Christophe Blanc,1  

E-Print Network [OSTI]

very low thermal conductances of highly rough silicon nanowires [7, 18], far below the amorphous limit, 2013) The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been of nanostructured materials or low dimen- sional materials has attracted growing interest [1­4], es- pecially

Paris-Sud XI, Université de

488

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

SciTech Connect (OSTI)

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.

Mahdavi, M., E-mail: m.mahdavi@umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Khodadadi Azadboni, F., E-mail: f.khodadadi@stu.umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Young Researchers Club, Sari Branch, Islamic Azad University, P.O. Box 48161-194, Sari (Iran, Islamic Republic of)

2014-02-15T23:59:59.000Z

489

The simple boundary element method for transient heat conduction in functionally graded materials  

E-Print Network [OSTI]

of functional material variation (quadratic, exponential and trigonometric) of thermal conductivity and specific, in an FGM, one face of a structural component is an engineering ceramic that can resist severe thermal ceramic and fracture- resisting metal can improve the properties of thermal barrier systems because

Paulino, Glaucio H.

490

Brine clarity maintenance in salinity-gradient solar ponds  

Science Journals Connector (OSTI)

Brine transparency is an important part of the maintenance of a salinity-gradient solar pond as it affects the amount of solar radiation reaching the storage zone and hence has an influence on the thermal performance. There is a wide range of factors that can hinder the transmission of light in a solar pond. Algal and microbial growths are the most common problems encountered in working solar ponds and control of their densities is essential to maintain transparency. Two different chemical treatment methods for algae growth prevention are described in this paper: chlorine and a novel chemical product – copper ethylamine complex. The latter method has never been implemented previously in a working pond. This paper discusses the theory of the algae control methods used and presents the experimental results of the chemical treatments. The results showed that Cupricide is more effective than chlorine and is therefore the recommended chemical for algae control in solar ponds; it improves the water transparency especially in the upper convective zone and lower convective zone with all measurement values less than 1 NTU. Chlorine was found to be more corrosive than Cupricide due to the acidic effect it has on the pH. The preliminary cost analysis showed that granular chlorine is the cheapest chemical. A more detailed financial analysis is nevertheless required to refine these costs.

Neus Gasulla; Yusli Yaakob; Jimmy Leblanc; Aliakbar Akbarzadeh; Jose Luis Cortina

2011-01-01T23:59:59.000Z

491

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network [OSTI]

using aquifers for thermal energy storage. Problems outlinedmatical Modeling of Thermal Energy Storage in Aquifers,"ings of Aquifer Thermal Energy Storage Workshop, Lawrence

Tsang, C.-F.

2011-01-01T23:59:59.000Z

492

Chiral Conductivities of Nanotubes  

Science Journals Connector (OSTI)

Chiral conductivities of nanotubes are examined within the framework of the Boltzmann transport equation. Electron transport along a chiral trajectory is decomposed into current components along the tubule axis and its circumference. Within a constant relaxation time approximation, these components are derived from the expectation values of Fermi velocities by using the appropriate operators and the wave functions at the Fermi level obtained by first-principles calculations. As a typical example, the chiral current of a doped BC2N tubule is illustrated, and the strength of the induced magnetic field is discussed.

Yoshiyuki Miyamoto; Steven G. Louie; Marvin L. Cohen

1996-03-18T23:59:59.000Z