Powered by Deep Web Technologies
Note: This page contains sample records for the topic "high 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.


1

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...

2

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...

3

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

4

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

5

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

6

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.

7

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.

8

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.

9

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

10

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

11

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

12

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

13

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

14

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.

15

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

16

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

17

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

18

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

19

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

20

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

Note: This page contains sample records for the topic "high 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

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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.

40

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

E-Print Network [OSTI]

537°C) steam for the steam turbine to generate electricity.as heat sources for steam turbines. Mainly three approachesto Stirling or Brayton steam turbine, moderate to high heat

Roshandell, Melina

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

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

42

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

43

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.

44

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

45

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

46

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

47

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

48

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

49

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

50

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

51

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

52

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...

53

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

54

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

55

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

56

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

57

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

58

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.

59

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

60

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

Note: This page contains sample records for the topic "high 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

1 Thermal Conductivity of Highly-Ordered Mesoporous 2 Titania Thin Films from 30 to 320 K  

E-Print Network [OSTI]

and electro- 27 chemical capacitors.1,2 They are also used as electrodes in dye- 28 sensitized solar cells3 sensors. Finally, other applications 32 include (i) highly specific chemical sensors and membranes,7 (ii

Pilon, Laurent

62

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

63

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

64

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

65

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

66

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

67

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

68

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

69

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

70

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

71

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

72

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

73

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...

74

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

75

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

76

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

77

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

78

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

79

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

80

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

Note: This page contains sample records for the topic "high 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 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

82

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

83

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

84

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

85

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

86

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

87

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

88

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.

89

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

90

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

91

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

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

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

96

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

97

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

98

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

99

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

100

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

Note: This page contains sample records for the topic "high 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

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

102

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

103

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

104

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

105

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

106

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

107

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

108

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

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

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.

112

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

113

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

114

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

115

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

116

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

117

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

118

High-Frequency Conductivity of Degenerate Semiconductors  

Science Journals Connector (OSTI)

The problem of high-frequency conductivity of a degenerate semiconductor is investigated by a kinetic description. The finite duration of encounters is taken into account in a self-consistent fashion which properly includes collective effects. This treatment is an extension for quantum plasmas of the Dawson-Oberman method given for classical plasmas.

Amiram Ron and Narkis Tzoar

1963-09-01T23:59:59.000Z

119

High-Temperature Thermal Array for Next Generation Solar Thermal...  

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

3 Q1 High-Temperature Thermal Array for Next Generation Solar Thermal Power Production - FY13 Q1 This document summarizes the progress of this Los Alamos National Laboratory...

120

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

Note: This page contains sample records for the topic "high 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

A SIMPLIFIED METHOD FOR UPSCALING COMPOSITE MATERIALS WITH HIGH CONTRAST OF THE CONDUCTIVITY  

E-Print Network [OSTI]

exchangers, are characterized by a low volume fraction of the highly conductive material (glass or metal that the composite materials have constant macroscopic thermal conductivity tensors, which in principle canA SIMPLIFIED METHOD FOR UPSCALING COMPOSITE MATERIALS WITH HIGH CONTRAST OF THE CONDUCTIVITY R

Lazarov, Raytcho

122

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

123

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

124

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.

125

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

126

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-

127

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

128

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

129

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

130

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

131

A Discussion of Conductivity Testing in High Temperature Membranes...  

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

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport) A Discussion of Conductivity Testing in High Temperature Membranes...

132

Conductive Rigid Skeleton Supported Silicon as High-Performance...  

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

Conductive Rigid Skeleton Supported Silicon as High-Performance Li-Ion Battery Anodes. Conductive Rigid Skeleton Supported Silicon as High-Performance Li-Ion Battery Anodes....

133

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.

134

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

135

Effect of Ion Correlations on High?Frequency Plasma Conductivity  

Science Journals Connector (OSTI)

In an earlier work the ac conductivity of a plasma was investigated by means of an elementary model. The validity of this model has been borne out by a rigorous treatment of plasma at thermal equilibrium. The elementary model is now extended to include the effects of ion correlations for arbitrary fixed ion distributions. For thermal equilibrium correlations it is found that the ion shielding reduces the maximum effective impact parameter by the factor (1 + Z)½ (i.e. both ions and electrons contribute to the shielding) for frequencies low compared to the plasma frequency ?p. For frequencies high compared to ?p the previous results obtain. The resistance due to the excitation of longitudinal waves at frequencies just in excess of ?p is reduced by the factor (1 + Z)?1. However if large?amplitude (nonthermal) ion fluctuations are present the longitudinal wave contribution to the resistance may be greatly enhanced.

John Dawson; Carl Oberman

1963-01-01T23:59:59.000Z

136

High Performance Thermal Interface Technology Overview  

E-Print Network [OSTI]

An overview on recent developments in thermal interfaces is given with a focus on a novel thermal interface technology that allows the formation of 2-3 times thinner bondlines with strongly improved thermal properties at lower assembly pressures. This is achieved using nested hierarchical surface channels to control the particle stacking with highly particle-filled materials. Reliability testing with thermal cycling has also demonstrated a decrease in thermal resistance after extended times with longer overall lifetime compared to a flat interface.

R. Linderman; T. Brunschwiler; B. Smith; B. Michel

2008-01-07T23:59:59.000Z

137

High Performance Thermal Interface Technology Overview  

E-Print Network [OSTI]

An overview on recent developments in thermal interfaces is given with a focus on a novel thermal interface technology that allows the formation of 2-3 times thinner bondlines with strongly improved thermal properties at lower assembly pressures. This is achieved using nested hierarchical surface channels to control the particle stacking with highly particle-filled materials. Reliability testing with thermal cycling has also demonstrated a decrease in thermal resistance after extended times with longer overall lifetime compared to a flat interface.

Linderman, R; Smith, B; Michel, B

2008-01-01T23:59:59.000Z

138

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

139

High thermal expansion, sealing glass  

DOE Patents [OSTI]

A glass composition is described for hermetically sealing to high thermal expansion materials such as aluminum alloys, stainless steels, copper, and copper/beryllium alloys, which includes between about 10 and about 25 mole percent Na[sub 2]O, between about 10 and about 25 mole percent K[sub 2]O, between about 5 and about 15 mole percent Al[sub 2]O[sub 3], between about 35 and about 50 mole percent P[sub 2]O[sub 5] and between about 5 and about 15 mole percent of one of PbO, BaO, and mixtures thereof. The composition, which may also include between 0 and about 5 mole percent Fe[sub 2]O[sub 3] and between 0 and about 10 mole percent B[sub 2]O[sub 3], has a thermal expansion coefficient in a range of between about 160 and 210[times]10[sup [minus]7]/C and a dissolution rate in a range of between about 2[times]10[sup [minus]7] and 2[times]10[sup [minus]9]g/cm[sup 2]-min. This composition is suitable to hermetically seal to metallic electrical components which will be subjected to humid environments over an extended period of time.

Brow, R.K.; Kovacic, L.

1993-11-16T23:59:59.000Z

140

Testing the physics of heat conduction using high pressure: crystals, glasses, and interfaces  

E-Print Network [OSTI]

, simplest case of thermal conductivity where resistive scattering dominates C() v() l() d C() = heatTesting the physics of heat conduction using high pressure: crystals, glasses, and interfaces David supported by CDAC and AFOSR #12;The story... · Use high pressure (gem anvil cells) to modify vibrational

Braun, Paul

Note: This page contains sample records for the topic "high 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

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

142

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

143

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

144

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

145

Thermal Strategies for High Efficiency Thermoelectric Power Generation...  

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

Thermal Strategies for High Efficiency Thermoelectric Power Generation Thermal Strategies for High Efficiency Thermoelectric Power Generation Developing integrated TE system...

146

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.

147

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

148

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.

149

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

150

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

151

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

152

Conduction of Electricity in Highly Insulating Liquids  

Science Journals Connector (OSTI)

Investigations have been made on the natural conductivity, and on the conductivity induced by gamma-rays in isooctane and liquid oxygen. The characteristics of the two types of conductivity are so very different that it may be concluded that the natural conductivity is not due to stray radiation or to cosmic rays. The curves for the natural conductivity are such that the current increases much faster than the field. Evidence is presented supporting Plumley's theory that the observed conductivity is due to dissociation of the liquids by the field, and against the view that it has a thermionic origin at the cathode, or the view that it is due to radiation. The prediction that the logarithm of the current should be a linear function of the square root of the field is verified. The much larger currents induced by gamma-rays rise at first rapidly and then more slowly in a manner indicating a slow approach toward saturation. The results fit Jaffé's formula satisfactorily.

Chia-Shan Pao

1943-08-01T23:59:59.000Z

153

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

154

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

155

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

156

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

157

Carbonate-salt-based composite materials for medium- and high-temperature thermal energy storage  

Science Journals Connector (OSTI)

Abstract This paper discusses composite materials based on inorganic salts for medium- and high-temperature thermal energy storage application. The composites consist of a phase change material (PCM), a ceramic material, and a high thermal conductivity material. The ceramic material forms a microstructural skeleton for encapsulation of the PCM and structural stability of the composites; the high thermal conductivity material enhances the overall thermal conductivity of the composites. Using a eutectic salt of lithium and sodium carbonates as the PCM, magnesium oxide as the ceramic skeleton, and either graphite flakes or carbon nanotubes as the thermal conductivity enhancer, we produced composites with good physical and chemical stability and high thermal conductivity. We found that the wettability of the molten salt on the ceramic and carbon materials significantly affects the microstructure of the composites.

Zhiwei Ge; Feng Ye; Hui Cao; Guanghui Leng; Yue Qin; Yulong Ding

2014-01-01T23:59:59.000Z

158

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

159

CRAD, Conduct of Operations - Oak Ridge National Laboratory High...  

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

Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR February...

160

Normal Conducting CW RF Gun Design for High Performance Electron Beams  

SciTech Connect (OSTI)

High repetition rate (>1 MHz), high charge (1 nC), low emittance (1 micron) electron beams are an important enabling technology for next generation light sources. Advanced Energy Systems has begun the development of an advanced, continuous-wave, normal-conducting radio frequency electron gun. This gun is designed to minimize thermal stress, allowing fabrication in copper, while providing low emittance electron beams. Beam dynamics performance will be presented along with thermal and stress analysis of the gun cavity design.

Bluem, Hans; Schultheiss, Tom; Young, L.M.; Rimmer, Robert

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

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

173

Experimental and Numerical Examination of the Thermal Transmittance of High  

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

Experimental and Numerical Examination of the Thermal Transmittance of High Experimental and Numerical Examination of the Thermal Transmittance of High Performance Window Frames Title Experimental and Numerical Examination of the Thermal Transmittance of High Performance Window Frames Publication Type Conference Paper LBNL Report Number LBNL-3886E Year of Publication 2010 Authors Gustavsen, Arlid, Goce Talev, Dariush K. Arasteh, Howdy Goudey, Christian Kohler, Sivert Uvsløkk, and Bjørn Petter Jelle Conference Name Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference Date Published Dec 5-9, 2010 Conference Location Clearwater Beach, FL Call Number LBNL-3886E Abstract While window frames typically represent 20-30% of the overall window area, their impact on the total window heat transfer rates may be much larger. This effect is even greater in low-conductance (highly insulating) windows which incorporate very low conductance glazings. Developing low-conductance window frames requires accurate simulation tools for product research and development.

174

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

175

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

176

Building Technologies Office: Shape-Stable and Highly Conductive  

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

Shape-Stable and Highly Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project to someone by E-mail Share Building Technologies Office: Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project on Facebook Tweet about Building Technologies Office: Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project on Twitter Bookmark Building Technologies Office: Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project on Google Bookmark Building Technologies Office: Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project on Delicious Rank Building Technologies Office: Shape-Stable and Highly Conductive Nano-Phase-Change Materials Research Project on Digg Find More places to share Building Technologies Office: Shape-Stable

177

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

178

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

179

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

180

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

Note: This page contains sample records for the topic "high 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

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

182

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

183

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

184

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

185

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

186

Optical and Thermal Characterization of High Reflective Surface with Applications in Thermal-Solar Technology  

Science Journals Connector (OSTI)

Selective solar absorbing coating consists of a high thermal reflectance layer and high solar absorbance layer deposited over a substrate. In this work optical and thermal properties...

Macias, Juan Daniel; Ramirez Rincon, Jorge Andres; Lizama Tzec, Francisco Ivan; Ares Muzio, Oscar Eduardo; Oskam, Gerko; De Coss Gomez, Romeo; Alvarado Gil, Juan José

187

Optical and Thermal Characterization of High Reflection Surfaces with Applcations in Thermal-Solar Technology  

Science Journals Connector (OSTI)

Selective solar absorbing coating consists of a high thermal reflectance layer and a high solar absorbance layer deposited over a substrate. In this work optical and thermal properties...

Macias, Juan Daniel; Ramirez Rincon, Jorge Andres; Lizama Tzec, Francisco Ivan; Ares Muzio, Oscar Eduardo; Oskam, Gerko; De Coss Gomez, Romeo; Alvarado Gil, Juan José

188

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

189

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

190

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

191

Evaluation of Thermal to Electrical Energy Conversion of High...  

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

Thermal to Electrical Energy Conversion of High Temperature Skutterudite-Based Thermoelectric Modules Evaluation of Thermal to Electrical Energy Conversion of High Temperature...

192

Dish Stirling High Performance Thermal Storage | Department of...  

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

Stirling High Performance Thermal Storage Dish Stirling High Performance Thermal Storage This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program...

193

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

194

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

195

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

196

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

197

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

198

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.

199

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

200

High-Temperature Thermal Array for Next Generation Solar Thermal...  

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

Thermal Array for Next Generation Solar Thermal Power Production Award Number: DE-EE00025828 Report Date: March 15, 2013 PI: Stephen Obrey * Technical approach is focused on...

Note: This page contains sample records for the topic "high 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

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

202

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

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

High-Efficiency Thermal Energy Storage System for CSP  

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

April 15. 2013 | Singh April 15. 2013 | Singh * Thermal modeling will be conducted to establish the benefits of using a high thermal conducting graphite foams in conjunction with PCM and to develop a design for a laboratory scale prototype. * Variety of characterizations will be carried out to qualify the materials (PCMs, alloys, coatings) for the prototype construction. * Process to infiltrate selected PCM into the foam will be developed. * Using the appropriate brazing/joining techniques, prototype will be assembled. * Performance testing of the TES system prototype to ensure a full- scale system will meet the SunShot goals. * Complete cost analysis of the proposed TES system * Complete laboratory scale prototype design * Develop SiC coating using polycarbosilanes for graphite

205

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

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

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

208

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

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

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

212

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

213

Process for introducing electrical conductivity into high-temperature polymeric materials  

DOE Patents [OSTI]

High-temperature electrically conducting polymers. The in situ reactions: AgNO.sub.3 +RCHO.fwdarw.Ag.degree.+RCOOH and R.sub.3 M.fwdarw.M.degree.+3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R.sub.3 M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone.

Liepins, Raimond (Los Alamos, NM); Jorgensen, Betty S. (Jemez Springs, NM); Liepins, Leila Z. (Los Alamos, NM)

1993-01-01T23:59:59.000Z

214

Thermal fuse for high-temperature batteries  

DOE Patents [OSTI]

A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

Jungst, Rudolph G. (Albuquerque, NM); Armijo, James R. (Albuquerque, NM); Frear, Darrel R. (Austin, TX)

2000-01-01T23:59:59.000Z

215

CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux  

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

Reactor Reactor CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux Isotope Reactor February 2007 A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for a February, 2007 assessment of the Conduct of Operations Program in preparation for restart of the Oak Ridge National Laboratory, High Flux Isotope Reactor. CRADs provide a recommended approach and the types of information to gather to assess elements of a DOE contractor's programs. CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux Isotope Reactor More Documents & Publications CRAD, Fire Protection - Oak Ridge National Laboratory High Flux Isotope

216

Conduction of Electricity by Dielectric Liquids at High Field Strengths  

Science Journals Connector (OSTI)

The conductivity of highly purified heptane has been measured between optical flats at field strengths up to 600,000 volts per cm at temperatures ranging from - 190°C to 20°C. Electrode separations down to 0.005 cm were used in order to minimize the effect of space charge and ionic recombination. It is concluded that electronic or collision processes are unlikely as the source of high field conductivity in heptane and probably most other liquid dielectrics as well. It is suggested that the highly nonconducting dielectric liquids should be included as extreme cases in the general class of weak electrolytes. The presence of appreciable conductivity under high electric fields is ascribed to the lowering of the energy of the hydrogen bond by the applied field.

H. J. Plumley

1941-01-15T23:59:59.000Z

217

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

218

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

219

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

220

CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux  

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

Reactor Contractor ORR Reactor Contractor ORR CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR February 2007 A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for a February, 2007 assessment of the Conduct of Operations Program portion of an Operational Readiness Review of the Oak Ridge National Laboratory, High Flux Isotope Reactor. CRADs provide a recommended approach and the types of information to gather to assess elements of a DOE contractor's programs. CRAD, Conduct of Operations - Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR More Documents & Publications

Note: This page contains sample records for the topic "high 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

High Temperature Thermal Array for Next Generation Solar Thermal...  

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

A 10% increase in shaft work is directly attributable to modified thermal heat capacity Engineering HTF Specific heat yields modified power output. 27 127 227 327 427 527...

222

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

223

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

224

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

225

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

226

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

227

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.

228

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

229

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

230

Thermal Transport in High-Strength Polymethacrylimide (PMI) Foam Insulations  

Science Journals Connector (OSTI)

Thermal transport in high-strength polymethacrylimide (PMI) foam insulations is described, with special emphasis on the... $$3\\omega $$ ...

L. Qiu; X. H. Zheng; J. Zhu; D. W. Tang…

2014-06-01T23:59:59.000Z

231

Multifunctional Nanoclay Hybrids of High Toughness, Thermal, and Barrier Performances  

Science Journals Connector (OSTI)

Multifunctional Nanoclay Hybrids of High Toughness, Thermal, and Barrier Performances ... functionalization of nanofillers, nanoclays or other compds. ...

Houssine Sehaqui; Joby Kochumalayil; Andong Liu; Tanja Zimmermann; Lars A. Berglund

2013-07-09T23:59:59.000Z

232

Electrical conductivity of wadsleyite at high temperatures and high pressures Lidong Dai a,b  

E-Print Network [OSTI]

Electrical conductivity of wadsleyite at high temperatures and high pressures Lidong Dai a,b , Shun 2009 Editor: L. Stixrude Keywords: electrical conductivity wadsleyite oxygen fugacity frequency water The electrical conductivity of wadsleyite aggregates has been determined under the broad range of thermodynamic

233

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

234

High-frequency conductivity of type-II superlattices  

Science Journals Connector (OSTI)

We carry out calculations of the conductivity and resistivity of an electron-hole many-layer system, i.e., a type-II superlattice, under the influence of electromagnetic waves whose frequencies are high compared to the collision frequencies and whose wavelengths are long compared to the Bohr (Debye) radius. The treatment rests on the Kubo’s formula for the conductivity and the temperature-dependent Green’s-function technique. An exact expression for the conductivity and resistivity is obtained, which is dependent on frequency, plasma parameter, spacing between adjacent layers, and density per unit area. We calculate the resistivity numerically for some typical values of the above four parameters.

Narkis Tzoar and Chao Zhang

1986-02-15T23:59:59.000Z

235

Project Profile: High-Efficiency Thermal Energy Storage System...  

Office of Environmental Management (EM)

the National Laboratory R&D competitive funding opportunity, will design, develop, and test a prototype high-temperature and high-efficiency thermal energy storage (TES) system...

236

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

237

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

238

RECENT IMPROVEMENTS IN HIGH?FREQUENCY EDDY CURRENT CONDUCTIVITY SPECTROSCOPY  

Science Journals Connector (OSTI)

Due to its frequency?dependent penetration depth eddy current measurements are capable of mapping near?surface residual stress profiles based on the so?called piezoresistivity effect i.e. the stress?dependence of electric conductivity. To capture the peak compressive residual stress in moderately shot?peened (Almen 4–8A) nickel?base superalloys the eddy current inspection frequency has to go as high as 50–80 MHz. Recently we have reported the development of a new high?frequency eddy current conductivity measuring system that offers an extended inspection frequency range up to 80 MHz. Unfortunately spurious self? and stray?capacitance effects render the complex coil impedance variation with lift?off more nonlinear as the frequency increases which makes it difficult to achieve accurate apparent eddy current conductivity (AECC) measurements with the standard four?point linear interpolation method beyond 25 MHz. In this paper we will demonstrate that reducing the coil size reduces its sensitivity to capacitive lift?off variations which is just the opposite of the better known inductive lift?off effect. Although reducing the coil size also reduces its absolute electric impedance and relative sensitivity to conductivity variations a smaller coil still yields better overall performance for residual stress assessment. In addition we will demonstrate the benefits of a semi?quadratic interpolation scheme that together with the reduced lift?off sensitivity of the smaller probe coil minimizes and in some cases completely eliminates the sensitivity of AECC measurements to lift?off uncertainties. These modifications allow us to do much more robust measurements up to as high as 80–100 MHz with the required high relative accuracy of +/?0.1%.

Bassam A. Abu?Nabah; Peter B. Nagy

2008-01-01T23:59:59.000Z

239

Highly conductive p-type microcrystalline silicon thin films  

SciTech Connect (OSTI)

In the development of thin film solar cells there is presently an increasing interest in microcrystalline silicon, deposited at low temperatures (200--400 C). The plasma deposition of boron doped microcrystalline films was optimized with respect to crystallinity and doping efficiency. High room temperature conductivities up to 39 Scm{sup {minus}1} were achieved under condition when the energy of positive ions impinging on the growth surface is minimized.

Heintze, M.; Schmitt, M. [Univ. Stuttgart (Germany). Inst. fuer Physikalische Elektronik

1996-12-31T23:59:59.000Z

240

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

Note: This page contains sample records for the topic "high 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

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

242

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

243

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

244

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

245

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

246

Project Profile: High-Temperature Thermal Array for Next-Generation...  

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

Thermal Array for Next-Generation Solar Thermal Power Production Project Profile: High-Temperature Thermal Array for Next-Generation Solar Thermal Power Production Los Alamos...

247

Thermal conductor for high-energy electrochemical cells  

DOE Patents [OSTI]

A thermal conductor for use with an electrochemical energy storage device is disclosed. The thermal conductor is attached to one or both of the anode and cathode contacts of an electrochemical cell. A resilient portion of the conductor varies in height or position to maintain contact between the conductor and an adjacent wall structure of a containment vessel in response to relative movement between the conductor and the wall structure. The thermal conductor conducts current into and out of the electrochemical cell and conducts thermal energy between the electrochemical cell and thermally conductive and electrically resistive material disposed between the conductor and the wall structure. The thermal conductor may be fabricated to include a resilient portion having one of a substantially C-shaped, double C-shaped, Z-shaped, V-shaped, O-shaped, S-shaped, or finger-shaped cross-section. An elastomeric spring element may be configured so as to be captured by the resilient conductor for purposes of enhancing the functionality of the thermal conductor. The spring element may include a protrusion that provides electrical insulation between the spring conductor and a spring conductor of an adjacently disposed electrochemical cell in the presence of relative movement between the cells and the wall structure. The thermal conductor may also be fabricated from a sheet of electrically conductive material and affixed to the contacts of a number of electrochemical cells.

Hoffman, Joseph A. (Minneapolis, MN); Domroese, Michael K. (South St. Paul, MN); Lindeman, David D. (Hudson, WI); Radewald, Vern E. (Austin, TX); Rouillard, Roger (Beloeil, CA); Trice, Jennifer L. (Eagan, MN)

2000-01-01T23:59:59.000Z

248

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

249

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

250

Study on thermal performance of high power LED employing aluminum filled epoxy composite as thermal interface material  

Science Journals Connector (OSTI)

Abstract This paper elucidates the thermal behavior of an LED employing metal filled polymer matrix as thermal interface material (TIM) for an enhanced heat dissipation characteristic. Highly thermal conductive aluminum (Al) particles were incorporated in bisphenol A diglycidylether (DGEBA) epoxy matrix to study the effect of filler to polymer ratio on the thermal performance of high power LEDs. The curing behavior of DGEBA was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The dispersion nature of the Al fillers in polymer matrix was verified with Field Emission Scanning Electron Microscope (FESEM). The thermal performance of synthesized Al filled polymer composite as TIM was tested with an LED employing thermal transient measurement technique. Comparing the filler to polymer ratio, the rise in junction temperature for 60 wt% Al filled composite was higher by 11.1 °C than 50 wt% Al filled composite at cured state. Observed also from the structure function analysis that the total thermal resistance was 10.96 K/W higher for 60 wt% Al filled composite compared to 50 wt% Al filled composite. On the other hand, a significant rise of 9.5 °C in the junction temperature between cured and uncured samples of 50 wt% Al filled polymer TIM was observed and hence the importance of curing process of metal filled polymer composite for effective heat dissipation is discussed extensively in this work.

P. Anithambigai; S. Shanmugan; D. Mutharasu; T. Zahner; D. Lacey

2014-01-01T23:59:59.000Z

251

Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress  

E-Print Network [OSTI]

PROPPANT FRACTURE CONDUCTIVITY WITH HIGH PROPPANT LOADING AND HIGH CLOSURE STRESS A Thesis by MATTHEW CHARLES RIVERS 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 May 2010 Major Subject: Petroleum Engineering PROPPANT FRACTURE CONDUCTIVITY WITH HIGH PROPPANT LOADING AND HIGH CLOSURE STRESS A Thesis by MATTHEW CHARLES RIVERS Submitted...

Rivers, Matthew Charles

2011-08-08T23:59:59.000Z

252

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

253

High-frequency conductivity of type-I superlattices  

Science Journals Connector (OSTI)

By using a method which employs a kinetic description and linear-response theory, we calculated the conductivity of electron-ion many-layer system (type-I superlattices) in the high-frequency and long-wavelength limits. Here electromagnetic radiation is taken to be a homogeneous, oscillating electric field. Our calculation takes into account all contributions in lowest order of the plasma parameter rs. Expressions for frequency-dependent scattering time and effective mass have been numerically obtained. Asymptotic limits for small and large frequencies are analytically derived.

Narkis Tzoar and Chao Zhang

1985-07-15T23:59:59.000Z

254

Colored solar-thermal absorbing coatings with high absorptance  

Science Journals Connector (OSTI)

It's difficult to obtain different color appearance and keep high absorptance simultaneously. We introduced AR films into solar-thermal absorbing coatings to tune the color appearance...

Wang, Shao-Wei; Chen, Feiliang; Liu, Xingxing; Wang, Xiaofang; Yu, Liming; Lu, Wei

255

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

256

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

257

Ultra low thermal expansion, highly thermal shock resistant ceramic  

DOE Patents [OSTI]

Three families of ceramic compositions having the given formula: .phi..sub.1+X Zr.sub.4 P.sub.6-2X Si.sub.2X O.sub.24, .phi..sub.1+X Zr.sub.4-2X Y.sub.2X P.sub.6 O.sub.24 and .phi..sub.1+X Zr.sub.4-X Y.sub.X P.sub.6-2X Si.sub.X O.sub.24 wherein .phi. is either Strontium or Barium and X has a value from about 0.2 to about 0.8 have been disclosed. Ceramics formed from these compositions exhibit very low, generally near neutral, thermal expansion over a wide range of elevated temperatures.

Limaye, Santosh Y. (1440 Sandpiper Cir. #38, Salt Lake City, UT 84117)

1996-01-01T23:59:59.000Z

258

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

259

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.

260

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

Note: This page contains sample records for the topic "high 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

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

262

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

263

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

264

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

265

Pulsed-laser crystallized highly conductive boron-doped microcrystalline silicon  

SciTech Connect (OSTI)

The preparation of seed lattices, using three interfering beams (TIB) from a pulsed Nd:YAG laser in a-Si layers of 100 to 400 nm thickness is introduced and applied for seeded laser or thermally induced crystallization of a-Si on Corning 7059 glass. The structural and electronic properties of the {micro}c-Si layers are investigated by X-ray, electron- and atomic force microscopy, Hall and conductivity measurements. In highly boron-doped {micro}c-Si, grains up to 1.3 {micro}m in diameter are detected, giving rise to conductivities of {approx}2,000 S/cm and hole mobilities of {approx}10 cm{sup 2}/Vs.

Nebel, C.E.; Dahlheimer, B.; Karrer, U.; Stutzmann, M.

1997-07-01T23:59:59.000Z

266

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

267

SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP  

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

High-Efficiency Thermal Energy Storage System for CSP High-Efficiency Thermal Energy Storage System for CSP ANL logo Photo of a black and white porous material magnified 50 times by a microscope. Microstructure of the highly thermal conductive foam that will be used for the prototype TES system. Image from ANL Argonne National Laboratory and project partner Ohio Aerospace Institute, under the National Laboratory R&D competitive funding opportunity, will design, develop, and test a prototype high-temperature and high-efficiency thermal energy storage (TES) system with rapid charging and discharging times. By increasing the efficiency of TES systems, this project aims to lower the capital costs of concentrating solar power (CSP) systems. Approach The research team is developing and evaluating a novel approach for TES at temperatures greater than 700ËšC for CSP systems. The approach uses high thermal conductivity and high-porosity graphite foams infiltrated with a phase change material (PCM) to provide TES in the form of latent heat.

268

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.

269

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.

270

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

271

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

272

HIGH TEMPERATURE CONDUCTIVITY PROBE FOR MONITORING CONTAMINATION LEVELS IN POWER PLANT BOILER WATER.  

E-Print Network [OSTI]

??A high temperature/high pressure flow through probe was designed to measure high temperature electrical conductivity of aqueous (aq) dilute electrolyte solutions, an application which can… (more)

Hipple, Sarah

2008-01-01T23:59:59.000Z

273

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

274

High-power TSP bits. [Thermally Stable Polycrystalline diamond  

SciTech Connect (OSTI)

This paper reviews a three-year R D project to develop advanced thermally stable polycrystalline diamond (TSP) bits that can operate at power levels 5 to 10 times greater than those typically delivered by rotary rigs. These bits are designed to operate on advanced drilling motors that drill 3 to 6 times faster than rotary rigs. TSP bit design parameters that were varied during these tests include cutter size, shape, density, and orientation. Drilling tests conducted in limestone, sandstone, marble, and granite blocks showed that these optimized bits drilled many of these rocks at 500 to 1,000 ft/hr (150 to 300 m/h), compared to 50 to 100 ft/hr (15 to 30 m/h) for roller bits. These tests demonstrated that TSP bits are capable of operating at the high speeds and high torques delivered by advanced drilling motors now being developed. These advanced bits and motors are designed for use in slim-hole and horizontal drilling applications.

Cohen, J.H.; Maurer, W.C. (Maurer Engineering Inc., Houston, TX (United States)); Westcott, P.A. (Gas Research Inst., Chicago, IL (United States))

1994-03-01T23:59:59.000Z

275

Fluoride based cathodes and electrolytes for high energy thermal batteries  

SciTech Connect (OSTI)

A research and development program is being conducted at the Saft Advanced Technologies Division in Hunt Valley, MD to double the energy density of a thermal battery. A study of high voltage cathodes to replace iron disulfide is in progress. Single cells are being studied with a lithium anode and either a copper(II) fluoride, silver(II) fluoride, or iron(III) fluoride cathode. Due to the high reactivity of these cathodes, conventional alkali metal chloride and bromide salt electrolytes must be replaced by alkali metal fluoride electrolytes. Parametric studies using design-of-experiments matrices will be performed so that the best cathode for an improved battery design can be selected. Titanium hardware for the design will provide a higher strength to weight ratio with lower emissivity than conventional stainless steel. The battery will consist of two power sections. The goals are battery activation in less than 0.2 s, 88 Wh/kg, 1,385 W/kg, and 179 Wh/L over an environmental temperature range of {minus}40 C to +70 C.

Briscoe, J.D.

1998-07-01T23:59:59.000Z

276

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.

277

Thermal Management of High-Performance Lithium-Ion Batteries  

Science Journals Connector (OSTI)

The battery power and lifetime depend to a large...cool...) is usually reduced using a high volumetric flow rate. Lathin technology from Behr ensures efficient temperature homogenisation (locally adapted thermal ...

Dr.-Ing. Matthias Stripf; Dr.-Ing. Manuel Wehowski…

2012-01-01T23:59:59.000Z

278

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

279

Encapsulation of copper-based phase change materials for high temperature thermal energy storage  

Science Journals Connector (OSTI)

Abstract Worldwide attention has been paid to high temperature phase change materials (PCMs) utilized in latent heat storage systems such as solar thermal power generation or industrial waste heat recovery. Current high temperature \\{PCMs\\} on basis of molten salts are suffering from inherent low thermal conductivity, which is detrimental to heat release rate and systematically thermal efficiency. Metal materials, always possessing ultrahigh thermal conductivity and satisfied heat fusion, are highly suitable as PCMs. However, the development of metal-based \\{PCMs\\} must overcome the package problem, namely, packing active, high temperature liquid metal into durable container. In this paper, copper capsules coated with refractory metallic shells were proposed as a novel metal PCM, which could work at temperature up to 1000 °C. Copper spheres with diameter of millimeters were encapsulated with a thick chromium–nickel bilayer by a novel chromium periodic-barrel electroplating method and nickel barrel-plating method. The latent heat density of as-prepared capsules is up to 75% of the theoretical value (about 71 J/g) at the melting temperature of 1077 °C and the thermal resistance of chromium–nickel layer is 8.27×10?6 m2 k/w. Particularly, copper capsules could endure 1000 charge–discharge thermal cycles from 1050 °C to 1150 °C without any leakage. The structure investigations reveal the excellent oxidation resistance of capsules and good stability between copper and chromium–nickel layer, even after long-term charge–discharge cycles. The results demonstrate that as-prepared copper capsules are applicable as high temperature \\{PCMs\\} which can facilitate high temperature thermal energy storage systems.

Guocai Zhang; Jianqiang Li; Yunfa Chen; Heng Xiang; Bingqian Ma; Zhe Xu; Xiaoguang Ma

2014-01-01T23:59:59.000Z

280

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.

Note: This page contains sample records for the topic "high 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.


281

Handbook for Planning and Conducting Charrettes for High-Performance Projects: Second Edition  

SciTech Connect (OSTI)

This handbook furnishes guidance for planning and conducting a high-performance building charrette, sometimes called a "greening charrette."

Lindsay, G.; Todd, J. A.; Hayter, S. J.; Ellis, P. G.

2009-09-01T23:59:59.000Z

282

Application Of High-Resolution Thermal Infrared Sensors For Geothermal  

Open Energy Info (EERE)

High-Resolution Thermal Infrared Sensors For Geothermal High-Resolution Thermal Infrared Sensors For Geothermal Exploration At The Salton Sea, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Application Of High-Resolution Thermal Infrared Sensors For Geothermal Exploration At The Salton Sea, California Details Activities (2) Areas (1) Regions (0) Abstract: The Salton Sea geothermal field straddles the southeast margin of the Salton Sea in California, USA. This field includes approximately 20km2 of mud volcanoes and mud pots and centered on the Mullet Island thermal anomaly. The area has been previously exploited for geothermal power; there are currently seven power plants in the area that produce 1000 MW. The field itself is relatively un-vegetated, which provides for unfettered

283

High elastic modulus polymer electrolytes suitable for preventing thermal runaway in lithium batteries  

DOE Patents [OSTI]

A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics. In another aspect, the electrolyte exhibits a conductivity drop when the temperature of electrolyte increases over a threshold temperature, thereby providing a shutoff mechanism for preventing thermal runaway in lithium battery cells.

Mullin, Scott; Panday, Ashoutosh; Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

2014-04-22T23:59:59.000Z

284

Natural convection with mixed insulating and conducting boundary conditions: low and high Rayleigh numbers regimes  

E-Print Network [OSTI]

We investigate the stability and dynamics of natural convection in two dimensions, subject to inhomogeneous boundary conditions. In particular, we consider a Rayleigh-B\\`enard (RB) cell, where the horizontal top boundary contains a periodic sequence of alternating thermal insulating and conducting patches, and we study the effects of the heterogeneous pattern on the global heat exchange, both at low and high Rayleigh numbers. At low Rayleigh numbers, we determine numerically the transition from a regime characterized by the presence of small convective cells localized at the inhomogeneous boundary to the onset of bulk convective rolls spanning the entire domain. Such a transition is also controlled analytically in the limit when the boundary pattern length is small compared with the cell vertical size. At higher Rayleigh number, we use numerical simulations based on a lattice Boltzmann method to assess the impact of boundary inhomogeneities on the fully turbulent regime up to $Ra \\sim 10^{10}$.

Ripesi, P; Sbragaglia, M; Wirth, A

2014-01-01T23:59:59.000Z

285

Capacitive conductivity logging and electrical stratigraphy in a high-resistivity aquifer, Boise Hydrogeophysical Research Site  

E-Print Network [OSTI]

Capacitive conductivity logging and electrical stratigraphy in a high-resistivity aquifer, Boise . Examining such a high-resistivity system provides a good test for the ca- pacitive-conductivity tool because the conventional induc- tion-conductivity tool known to have limited effectiveness in high-resistivity systems did

Barrash, Warren

286

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport)  

Broader source: Energy.gov [DOE]

Presentation on conductivity testing in high temperature membranes given by Jim Boncella of Los Alamos National Laboratory at the High Temperature Membrane Working Group meeting in October 2005.

287

Contact resistance measurements recorded at conductive polymer/high-temperature superconductor interfaces  

Science Journals Connector (OSTI)

Contact resistance measurements recorded at conductive polymer/high-temperature superconductor interfaces ... Structure of the Electrical Double Layer in High-Temperature Superconductors. ...

Steven G. Haupt; David R. Riley; Jianai Zhao; John T. McDevitt

1993-01-01T23:59:59.000Z

288

Electrical conductivity of noble gases at high pressures  

Science Journals Connector (OSTI)

Theoretical results for the electrical conductivity of noble gas plasmas are presented in comparison with experiment. The composition is determined within a partially ionized plasma model. The conductivity is then calculated using linear response theory, in which the relevant scattering mechanisms of electrons from ions, electrons, and neutral species are taken into account. In particular, the Ramsauer-Townsend effect in electron-neutral scattering is discussed and the importance of a correct description of the Coulomb logarithm in electron scattering by charged particles is shown. A detailed comparison with recent experiments on argon and xenon plasmas is given and results for helium and neon are also revisited. Excellent agreement between theory and experiment is observed, showing considerable improvement upon previous calculations.

J. R. Adams, H. Reinholz, R. Redmer, V. B. Mintsev, N. S. Shilkin, and V. K. Gryaznov

2007-09-21T23:59:59.000Z

289

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

290

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

291

Influence of nano-ZrO2 on the mechanical and thermal properties of high temperature cementitious thermal energy storage materials  

Science Journals Connector (OSTI)

Abstract The mechanical and thermal properties of high temperature aluminate cementitious thermal energy storage materials modified with nano-ZrO2 are investigated. The influence of nano-ZrO2 amounts on the performance, such as compressive strength, thermal conductivity, volume heat capacity, and thermal expansion coefficient, of hardened composite cement pastes were studied for future solar thermal energy materials with better performance. It is observed that before heating the pore structure and compressive strength are both optimized at the optimum nano-ZrO2 amount of 1 wt%. At the same time, thermal conductivity and volume heat capacity of the composite paste enriched with nano-ZrO2 improved after heating at 350 and 900 °C compared with that of pure paste, which is very favorable for high thermal storage materials application. XRD, TG–DSC, FTIR, and MIP were used to characterize the mineral phases, the hydration/dehydration evolution, the chemical bonding, and the pore structures of the hydration products, respectively.

Huiwen Yuan; Yu Shi; Zhongzi Xu; Chunhua Lu; Yaru Ni; Xianghui Lan

2013-01-01T23:59:59.000Z

292

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

293

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

294

All-solid-state high-power conduction-cooled Nd:YLF rod laser  

Science Journals Connector (OSTI)

A high-average-power conduction-cooled diode-pumped Nd:YLF rod laser has been developed. A new conduction-cooled side-pumping scheme with a solid prismatic pump-light confinement...

Hirano, Y; Yanagisawa, T; Ueno, S; Tajime, T; Uchino, O; Nagai, T; Nagasawa, C

2000-01-01T23:59:59.000Z

295

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

296

Thermal stability of high temperature structural alloys  

SciTech Connect (OSTI)

High temperature structural alloys were evaluated for suitability for long term operation at elevated temperatures. The effect of elevated temperature exposure on the microstructure and mechanical properties of a number of alloys was characterized. Fe-based alloys (330 stainless steel, 800H, and mechanically alloyed MA 956), and Ni-based alloys (Hastelloy X, Haynes 230, Alloy 718, and mechanically alloyed MA 758) were evaluated for room temperature tensile and impact toughness properties after exposure at 750 C for 10,000 hours. Of the Fe-based alloys evaluated, 330 stainless steel and 800H showed secondary carbide (M{sub 23}C{sub 6}) precipitation and a corresponding reduction in ductility and toughness as compared to the as-received condition. Within the group of Ni-based alloys tested, Alloy 718 showed the most dramatic structure change as it formed delta phase during 10,000 hours of exposure at 750 C with significant reductions in strength, ductility, and toughness. Haynes 230 and Hastelloy X showed significant M{sub 23}C{sub 6} carbide precipitation and a resulting reduction in ductility and toughness. Haynes 230 was also evaluated after 10,000 hours of exposure at 850, 950, and 1050 C. For the 750--950 C exposures the M{sub 23}C{sub 6} carbides in Haynes 230 coarsened. This resulted in large reductions in impact strength and ductility for the 750, 850 and 950 C specimens. The 1050 C exposure specimens showed the resolution of M{sub 23}C{sub 6} secondary carbides, and mechanical properties similar to the as-received solution annealed condition.

Jordan, C.E.; Rasefske, R.K.; Castagna, A. [Lockheed Martin Corp., Schenectady, NY (United States)

1999-03-01T23:59:59.000Z

297

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

298

Thermal and Power Challenges in High Performance Computing Systems  

Science Journals Connector (OSTI)

This paper provides an overview of the thermal and power challenges in emerging high performance computing platforms. The advent of new sophisticated applications in highly diverse areas such as health, education, finance, entertainment, etc. is driving the platform and device requirements for future systems. The key ingredients of future platforms are vertically integrated (3D) die-stacked devices which provide the required performance characteristics with the associated form factor advantages. Two of the major challenges to the design of through silicon via (TSV) based 3D stacked technologies are (i) effective thermal management and (ii) efficient power delivery mechanisms. Some of the key challenges that are articulated in this paper include hot-spot superposition and intensification in a 3D stack, design/optimization of thermal through silicon vias (TTSVs), non-uniform power loading of multi-die stacks, efficient on-chip power delivery, minimization of electrical hotspots etc.

Venkat Natarajan; Anand Deshpande; Sudarshan Solanki; Arun Chandrasekhar

2009-01-01T23:59:59.000Z

299

Thermal management and overall performance of a high concentration PV  

Science Journals Connector (OSTI)

An advanced thermal management approach for HCPV systems is demonstrated in this manuscript proposing the concept of efficient heat recovery at ultra high concentration ratios by collecting the heat on a high temperature level. With the availability of this low grade heat the efficiency of the HCPV system is increased further as the 'waste' heat is supplied to different thermal consumers engaging in thermal desalination or adsorption cooling processes. To asses the value of the concept we have estimated the economic value of heat with regard to its consumer and observed that this differs from its thermodynamic value. This valuable input is was used to determine the overall generated value of a dual output system as a function of the operation temperature where we have actively demonstrated a superior performance of the HCPVT.

Werner Escher; Stephan Paredes; Severin Zimmermann; Chin Lee Ong

2012-01-01T23:59:59.000Z

300

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

SciTech Connect (OSTI)

In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

Tarau, Calin; Walker, Kara L.; Anderson, William G. [Advanced Cooling Technologies, Inc. 1046 New Holland Ave. Lancaster, PA 17601 (United States)

2009-03-16T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

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

302

High temperature latent heat thermal energy storage: Phase change materials, design considerations and performance enhancement techniques  

Science Journals Connector (OSTI)

Abstract A very common problem in solar power generation plants and various other industrial processes is the existing gap between the period of thermal energy availability and its period of usage. This situation creates the need for an effective method by which excess heat can be stored for later use. Latent heat thermal energy storage is one of the most efficient ways of storing thermal energy through which the disparity between energy production or availability and consumption can be corrected, thus avoiding wastage and increasing the process efficiency. This paper reviews a series of phase change materials, mainly inorganic salt compositions and metallic alloys, which could potentially be used as storage media in a high temperature (above 300 °C) latent heat storage system, seeking to serve the reader as a comprehensive thermophysical properties database to facilitate the material selection task for high temperature applications. Widespread utilization of latent heat storage systems has been held back by the poor thermal conductivity and some other inherent drawbacks of the use of PCMs; this paper reviews several heat transfer and performance enhancement techniques proposed in the literature and discusses a number of design considerations that must be taken into account aiming to provide a broad overview for the design of high temperature latent heat based thermal energy storage systems.

Bruno Cárdenas; Noel León

2013-01-01T23:59:59.000Z

303

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...

304

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

305

Determination of Thermal Diffusivities, Thermal Conductivities, and Sound Speeds of Room-Temperature Ionic Liquids by the Transient Grating Technique  

E-Print Network [OSTI]

properties, which make them suitable not only as green solvents but also as high-performance fluids for use as a "green" recyclable alternative to the volatile organic compounds that are traditionally used as industrial solvents. In the laboratory, RTILs have successfully been used in a broad spectrum of applications

Reid, Scott A.

306

Applications of heat pipes for high thermal load beam lines  

SciTech Connect (OSTI)

The high flux beam produced by insertion devices often requires special heat removal techniques. For the optical elements used in such high thermal load beam lines, the required precision demands a highly accurate design. Heat pipe cooling of critical elements of the X-1 beam line at the National Synchrotron Light Source is described. This method reduces vibrations caused by water cooling systems and simplifies the design. In some of these designs, deposited heat must be transferred through unbonded contact interfaces. A pinhole assembly and a beam position monitor designed for the X-1 beam line both transfer heat through such interfaces in an ultrahigh vacuum environment. The fundamental design objective is that of removing the heat with minimal interface thermal resistance. We present our test method and results for measuring the thermal resistance across metallic interfaces as a function of contact pressure. The design of some devices which utilize both heat pipes and thermal contact interfaces will also be described. 12 refs., 8 figs.

Shu, D.; Mortazavi, P.; Rarback, H.; Howells, M.R.

1985-01-01T23:59:59.000Z

307

High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture  

SciTech Connect (OSTI)

Conductive polymers are of particular interest for thermoelectric applications due to their low thermal conductivity and relatively high electrical conductivity. In this study, commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) was used in a hybrid metal/polymer/metal thin film design in order to achieve a high Seebeck coefficient with the value of 252lV/k on a relatively low temperature scale. Polymer film thickness was varied in order to investigate its influence on the Seebeck effect. The high Seebeck coefficient indicates that the metal/polymer/metal design can develop a large entropy difference in internal energy of charge carriers between high and low-temperature metal electrodes to develop electrical potential due to charge transport in conducting polymer film through metal/polymer interface. Therefore, the metal/polymer/metal structure presents a new design to combine inorganic metals and organic polymers in thin-film form to develop Seebeck devices

Stanford, Michael G [ORNL; Wang, Hsin [ORNL; Ivanov, Ilia N [ORNL; Hu, Bin [University of Tennessee, Knoxville (UTK)

2012-01-01T23:59:59.000Z

308

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

309

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

310

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

311

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

312

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

313

Graphene-Multilayer Graphene Nanocomposites as Highly Efficient Thermal Interface Materials  

E-Print Network [OSTI]

resistance at the graphene-matrix interface. KEYWORDS: Graphene, thermal interface materials, nanocompositesGraphene-Multilayer Graphene Nanocomposites as Highly Efficient Thermal Interface Materials Khan M suggest that graphene-multilayer graphene nanocomposite used as the thermal interface material outperforms

314

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

315

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

316

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

317

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

318

Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications  

SciTech Connect (OSTI)

The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HPTM CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ~0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of ~3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive candidate for certain fusion energy structural applications. Conversely, CuNiBe may not be preferred at intermediate temperatures of 250-500 C due to the poor ductility and fracture toughness of CuNiBe alloys at temperatures >250 C. The potential deformation mechanisms responsible for the transition from transgranular to intergranular fracture are discussed. The possible implications for other precipitation hardened alloys such as nickel based superalloys are briefly discussed.

Zinkle, Steven J [ORNL] [ORNL

2014-01-01T23:59:59.000Z

319

SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP  

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

High-Efficiency Thermal Energy High-Efficiency Thermal Energy Storage System for CSP to someone by E-mail Share SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on Facebook Tweet about SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on Twitter Bookmark SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on Google Bookmark SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on Delicious Rank SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on Digg Find More places to share SunShot Initiative: High-Efficiency Thermal Energy Storage System for CSP on AddThis.com... Concentrating Solar Power Systems Components Competitive Awards CSP Research & Development Thermal Storage CSP Recovery Act

320

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

Note: This page contains sample records for the topic "high 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

Metal Hydride Thermal Storage: Reversible Metal Hydride Thermal Storage for High-Temperature Power Generation Systems  

SciTech Connect (OSTI)

HEATS Project: PNNL is developing a thermal energy storage system based on a Reversible Metal Hydride Thermochemical (RMHT) system, which uses metal hydride as a heat storage material. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. PNNL’s metal hydride material can reversibly store heat as hydrogen cycles in and out of the material. In a RHMT system, metal hydrides remain stable in high temperatures (600- 800°C). A high-temperature tank in PNNL’s storage system releases heat as hydrogen is absorbed, and a low-temperature tank stores the heat until it is needed. The low-cost material and simplicity of PNNL’s thermal energy storage system is expected to keep costs down. The system has the potential to significantly increase energy density.

None

2011-12-05T23:59:59.000Z

322

MODELLING OF EXPLOSIVE EVENTS IN THE SOLAR TRANSITION REGION: IMPORTANCE OF RADIATIVE LOSSES AND THERMAL CONDUCTION  

E-Print Network [OSTI]

taken with the NRL High Resolution Telescope and Spectrograph (HRTS) (Brueckner & Bartoe 1983) show,b). The most complete statistical description to­date of explosive events can be found in Brueckner & Bartoe

323

Energy Loss by Thermal Conduction and Natural Convection in Annular Solar Receivers  

Science Journals Connector (OSTI)

An effective device for the collection of solar energy is the so-called parabolic-cylindrical solar collector. In this device, a circular ... high temperature receiver tube designs the rate of energy loss by comb...

A. C. Ratzel; C. E. Hickox; D. K. Gartling

1978-01-01T23:59:59.000Z

324

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

325

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

326

High-Velocity Oxygen Fuel Thermal Spray of Fe-Based Amorphous Alloy: a Numerical and Experimental Study  

E-Print Network [OSTI]

High-Velocity Oxygen Fuel Thermal Spray of Fe-Basedusing a high velocity oxygen fuel (HVOF) spray processstructure. [12] High velocity oxygen fuel (HVOF) thermal

Ajdelsztajn, L.; Dannenberg, J.; Lopez, J.; Yang, N.; Farmer, J.; Lavernia, E. J.

2009-01-01T23:59:59.000Z

327

Project Profile: High-Temperature Thermal Array for Next-Generation Solar Thermal Power Production  

Broader source: Energy.gov [DOE]

The Los Alamos National Laboratory (ORNL), under the National Laboratory R&D competitive funding opportunity, is developing a megawatt-scale heat pipe–based technology designed to bridge the heliostat reflector field and the power cycle by replacing both the solar receiver and the heat transfer fluid (HTF) system used in concentrating solar power (CSP) systems. The technology, called the high-temperature thermal array, aims to achieve the SunShot Initiative's goals by addressing technical challenges, reducing capital and operating expenses, and increasing net photon-to-electricity conversion efficiency.

328

High-Temperature Air-Cooled Power Electronics Thermal Design (Presentation)  

SciTech Connect (OSTI)

This presentation discusses the status of research at NREL on high temperature air-cooled power electronics thermal design.

Waye, S.

2014-06-01T23:59:59.000Z

329

Thermal model design and analysis of the high-power LED automotive headlight cooling device  

Science Journals Connector (OSTI)

Abstract A study of the thermal performance of conventional plate-fin heat sinks and novel cooling device integrated with heat conductive plates (HCPS) for the application in high-power LED headlight was presented. The thermal resistance network model was built to analyze the factors which have impacts on the junction temperature. The analyses were based on the experiment combined with computations using the CFD software FloEFD. The prediction results were validated with the experimental one. Details of the heat transfer performance, particularly the temperature distribution of the LED module and lampshell, as well as the effect of HCPS length on the system thermal resistance and the average heat transfer coefficient were obtained. Since it could make some distance between the heat sink and the lampshell, the average surface convective heat transfer coefficient had been improved and the overall external thermal resistance was reduced effectively. The effects of the simulated ambient temperature, chip package depth, inclination angles and fan rotate speeds on the junction temperature were also examined. Results indicated that the airflow was weakened as the chip package depth increased. In addition, with the presence of the enforced velocity airflow, the junction temperature decreased gradually from 116.61 °C to 78.05 °C.

Xin-Jie Zhao; Yi-Xi Cai; Jing Wang; Xiao-Hua Li; Chun Zhang

2015-01-01T23:59:59.000Z

330

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

331

Enhanced performance of high temperature aluminate cementitious materials incorporated with Cu powders for thermal energy storage  

Science Journals Connector (OSTI)

Abstract Cementitious materials have been extensively developed in thermal energy storage system of solar thermal power. This paper deals with the volume heat capacity, thermal conductivity, thermal expansion coefficient, and compressive strength of aluminate cementitious thermal energy storage materials with the addition of metal Cu powders. The specimens were subjected to heat-treatment at 105, 350, and 900 °C, respectively. In the heating process, Cu powders gradually oxidized to Cu2O and CuO, providing a so-called mass compensation mechanism for the composite paste. Meanwhile, it indicates that volume heat capacity and thermal conductivity both increase with increasing Cu powders content and decrease with the rising temperature. The optimum thermal properties were obtained at 15 wt% Cu powders loading. In addition, Calorimetric Test, XRD, TG–DSC, and MIP are performed for characterizing the hydration rates, the phases, the mass/heat evolution, and the pore distribution, respectively.

Huiwen Yuan; Yu Shi; Chunhua Lu; Zhongzi Xu; Yaru Ni; Xianghui Lan

2015-01-01T23:59:59.000Z

332

High-Frequency Conductivity of a Plasma in Quasiequilibrium. I. Formulation of the General Theory  

Science Journals Connector (OSTI)

A general expression for the high-frequency conductivity is derived from the Bogolyubov-Born-Green-Kirkwood-Yvon hierarchy for a fully ionized plasma whose unperturbed state is stable. The result includes all the effects due to the high-frequency field and the collective interactions up to first order in the plasma parameter.

Ching-Sheng Wu

1965-04-05T23:59:59.000Z

333

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

334

Simulation of the high temperature impression of thermal barrier coatings with columnar microstructure  

E-Print Network [OSTI]

the deformation resistance of actual EB-PVD layers and its application to a range of thermal barrier materials [9Simulation of the high temperature impression of thermal barrier coatings with columnar of thermal barrier coatings (TBCs) are affected by their high temperature mechanical properties: especially

Hutchinson, John W.

335

BismuthCeramic Nanocomposites with Unusual Thermal Stability via High-Energy Ball Milling**  

E-Print Network [OSTI]

Bismuth±Ceramic Nanocomposites with Unusual Thermal Stability via High-Energy Ball Milling, nanostructured bismuth±ceramic nanocomposites with unusual thermal stabil- ity. These materials contain a high. Important for electrical and thermoelectric applications, the ceramic phase is electrically and thermally

Braun, Paul

336

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

337

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

338

Design and optimization of a high thermal flux research reactor via Kriging-based algorithm  

E-Print Network [OSTI]

In response to increasing demands for the services of research reactors, a 5 MW LEU-fueled research reactor core is developed and optimized to provide high thermal flux within specified limits upon thermal hydraulic ...

Kempf, Stephanie Anne

2011-01-01T23:59:59.000Z

339

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

340

Highly conductive p-type amorphous oxides from low-temperature solution processing  

SciTech Connect (OSTI)

We report solution-processed, highly conductive (resistivity 1.3-3.8 m{Omega} cm), p-type amorphous A-B-O (A = Bi, Pb; B = Ru, Ir), processable at temperatures (down to 240 Degree-Sign C) that are compatible with plastic substrates. The film surfaces are smooth on the atomic scale. Bi-Ru-O was analyzed in detail. A small optical bandgap (0.2 eV) with a valence band maximum (VBM) below but very close to the Fermi level (binding energy E{sub VBM} = 0.04 eV) explains the high conductivity and suggests that they are degenerated semiconductors. The conductivity changes from three-dimensional to two-dimensional with decreasing temperature across 25 K.

Li Jinwang [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Tokumitsu, Eisuke [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259-R2-19 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Koyano, Mikio [Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Mitani, Tadaoki [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Shimoda, Tatsuya [Japan Science and Technology Agency (JST), ERATO, Shimoda Nano-Liquid Process Project, 2-5-3 Asahidai, Nomi, Ishikawa 923-1211 (Japan); Green Devices Research Center, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

2012-09-24T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

Journal of Membrane Science 239 (2004) 1726 Highly conductive ordered heterogeneous ion-exchange membranes  

E-Print Network [OSTI]

in the matrix required for reasonable ion transport through the membrane is 50­70 wt.% [2Journal of Membrane Science 239 (2004) 17­26 Highly conductive ordered heterogeneous ion-exchange membranes are used in electrodialysis (ED) as ion-selective membranes and in power sources (such as fuel

Freger, Viatcheslav "Slava"

342

CRAD, Conduct of Operations- Oak Ridge National Laboratory High Flux Isotope Reactor  

Broader source: Energy.gov [DOE]

A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for a February, 2007 assessment of the Conduct of Operations Program in preparation for restart of the Oak Ridge National Laboratory, High Flux Isotope Reactor.

343

CRAD, Conduct of Operations- Oak Ridge National Laboratory High Flux Isotope Reactor Contractor ORR  

Broader source: Energy.gov [DOE]

A section of Appendix C to DOE G 226.1-2 "Federal Line Management Oversight of Department of Energy Nuclear Facilities." Consists of Criteria Review and Approach Documents (CRADs) used for a February, 2007 assessment of the Conduct of Operations Program portion of an Operational Readiness Review of the Oak Ridge National Laboratory, High Flux Isotope Reactor.

344

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

345

Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports  

SciTech Connect (OSTI)

Skutterudites CoSb{sub 3} with multiple cofillers Ba, La, and Yb were synthesized and very high thermoelectric figure of merit ZT = 1.7 at 850 K was realized. X-ray diffraction of the densified multiple-filled bulk samples reveals all samples are phase pure. High-resolution scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) analysis confirm that multiple guest fillers occupy the nanoscale-cages in the skutterudites. The fillers are further shown to be uniformly distributed and the Co-Sb skutterudite framework is virtually unperturbed from atomic scale to a few micrometers. Our results firmly show that high power factors can be realized by adjusting the total filling fraction of fillers with different charge states to reach the optimum carrier density, at the same time, lattice thermal conductivity can also be significantly reduced, to values near the glass limit of these materials, through combining filler species of different rattling frequencies to achieve broad-frequency phonon scattering. Therefore, partially filled skutterudites with multiple fillers of different chemical nature render unique structural characteristics for optimizing electrical and thermal transports in a relatively independent way, leading to continually enhanced ZT values from single- to double-, and finally to multiple-filled skutterudites. The idea of combining multiple fillers with different charge states and rattling frequencies for performance optimization is also expected to be valid for other caged TE compounds.

Zhang, Weiqing [Chinese Academy of Sciences; Yang, Jiong [Chinese Academy of Sciences; Yang, Jihui [General Motors Corporation; Wang, Hsin [ORNL; Salvador, James R. [GM R& D and Planning, Warren, Michigan; Shi, Xun [General Motors Corporation-R& D; Chi, Miaofang [ORNL; Cho, Jung Y [GM R& D and Planning, Warren, Michigan; Bai, Shengqiang [Chinese Academy of Sciences; Chen, Lidong [Chinese Academy of Sciences

2011-01-01T23:59:59.000Z

346

Detailed thermal performance data on conventional and highly insulating window systems  

SciTech Connect (OSTI)

Data on window heat-transfer properties (U-value and shading coefficient (SC)) are usually presented only for a few window designs at specific environmental conditions. With the introduction of many new window glazing configurations (using low-emissivity coatings and gas fills) and the interest in their annual energy performance, it is important to understand the effects of window design parameters and environmental conditions on U and SC. This paper discusses the effects of outdoor temperature, wind speed, insolation, surface emittance, and gap width on the thermal performance of both conventional and highly insulating windows. Some of these data have been incorporated into the fenestration chapter of the ''ASHRAE Handbook - 1985 Fundamentals.'' The heat-transfer properties of multiglazed insulating window designs are also presented. These window systems include those having (1) one or more low-emittance coatings; (2) low-conductivity gas-fill or evacuated cavities; (3) a layer of transparent silica aerogel, a highly insulating microporous material; or (4) combinations of the above. Using the detailed building energy analysis program, DOE 2.1B, we show that these systems, which all maintain high solar transmittance, can add more useful thermal energy to a space than they lose, even in a northern climate. Thus, in terms of seasonal energy flows, these fenestration systems out-perform insulated walls or roofs.

Arasteh, D.; Selkowitz, S.; Hartmann, J.

1986-01-01T23:59:59.000Z

347

Rotational remanent magnetization (RRM) and its high temporal and thermal stability  

Science Journals Connector (OSTI)

......and its high temporal and thermal stability S. W. Mahon* and...per cent per decade of time. Thermal demagnetization of thermoremanent...To test the temporal and thermal stability of RRM, a source...Neolithic pot 05 162 Soba (Sudan) Post-Roman pot 07 73 Soba......

S. W. Mahon; A. Stephenson

1997-08-01T23:59:59.000Z

348

Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels  

Science Journals Connector (OSTI)

Azobenzene-Functionalized Carbon Nanotubes As High-Energy Density Solar Thermal Fuels ... Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. ... Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. ...

Alexie M. Kolpak; Jeffrey C. Grossman

2011-06-20T23:59:59.000Z

349

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

350

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

351

Thick Thermal Barrier Coatings (TTBCs) for Low Emission, High Efficiency Diesel Engine Components  

SciTech Connect (OSTI)

The objective of this program was to advance the fundamental understanding of thick thermal barrier coating (TTBC) systems for application to low heat rejection diesel engine combustion chambers. Previous reviews of thermal barrier coating technology concluded that the current level of understanding of coating system behavior is inadequate and the lack of fundamental understanding may impede the application of thermal barrier coating to diesel engines.(1) Areas of TTBC technology examined in this program include powder characteristics and chemistry; bond coating composition, coating design, microstructure and thickness as they affect properties, durability, and reliability; and TTBC "aging" effects (microstructural and property changes) under diesel engine operating conditions. Fifteen TTBC ceramic powders were evaluated. These powders were selected to investigate the effects of different chemistries, different manufacturing methods, lot-to-lot variations, different suppliers and varying impurity levels. Each of the fifteen materials has been sprayed using 36 parameters selected by a design of experiments (DOE) to determine the effects of primary gas (Ar and N2), primary gas flow rate, voltage, arc current, powder feed rate, carrier gas flow rate, and spraying distance. The deposition efficiency, density, and thermal conductivity of the resulting coatings were measured. A coating with a high deposition efficiency and low thermal conductivity is desired from an economic standpoint. An optimum combination of thermal conductivity and disposition efficiency was found for each lot of powder in follow-on experiments and disposition parameters were chosen for full characterization.(2) Strengths of the optimized coatings were determined using 4-point bending specimens. The tensile strength was determined using free-standing coatings made by spraying onto mild steel substrates which were subsequently removed by chemical etching. The compressive strengths of the coatings were determined using composite specimens of ceramic coated onto stainless steel substrates, tested with the coating in compression and the steel in tension. The strength of the coating was determined from an elastic bi-material analysis of the resulting failure of the coating in compression.(3) Altough initial comparisons of the materials would appear to be straight forward from these results, the results of the aging tests of the materials are necessary to insure that trends in properties remain after long term exposure to a diesel environment. Some comparisons can be made, such as the comparison between for lot-to-lot variation. An axial fatigue test to determine the high cycle fatigue behavior of TTBCs was developed at the University of Illinois under funding from this program.(4) A fatigue test apparatus has been designed and initial work performed which demonstrates the ability to provide a routine method of axial testing of coating. The test fixture replaces the normal load frame and fixtures used to transmit the hydraulic oil loading to the sample with the TTBC specimen itself. The TTBC specimen is a composite metal/coating with stainless steel ends. The coating is sprayed onto a mild steel center tube section onto which the stainless steel ends are press fit. The specimen is then machined. After machining, the specimen is placed in an acid bath which etches the mild steel away leaving the TTBC attached to the the stainless steel ends. Plugs are then installed in the ends and the composite specimen loaded in the test fixture where the hydraulic oil pressurizes each end to apply the load. Since oil transmits the load, bending loads are minimized. This test fixture has been modified to allow piston ends to be attached to the specimen which allows tensile loading as well as compressive loading of the specimen. In addition to the room temperature data, specimens have been tested at 800 Degrees C with the surprising result that at high temperature, the TTBC exhibits much higher fatigue strength. Testing of the TTBC using tension/compression cycling has been con

M. Brad Beardsley, Caterpillar Inc.; Dr. Darrell Socie, University of Illinois; Dr. Ed Redja, University of Illinois; Dr. Christopher Berndt, State University of New York at Stony Brook

2006-03-02T23:59:59.000Z

352

Thermal expansion of manganese dioxide using high-temperature in situ X-ray diffraction  

Science Journals Connector (OSTI)

The thermal expansion behaviour of manganese dioxide, an important battery material, is reported using high-temperature in situ X-ray diffraction between 298 and 673 K.

Dose, W.M.

2013-08-03T23:59:59.000Z

353

Quantum-statistical approach to the electrical conductivity of dense, high-temperature plasmas  

Science Journals Connector (OSTI)

On the basis of a quantum-statistical formulation of electronic transport in charged-particle systems, the electrical conductivity of a high-density fully ionized plasma is evaluated using a diagram representation of the Matsubara Green functions. Many-particle effects such as the Debye-Onsager relaxation effect are investigated, and a low-density expansion of the inverse conductivity ?-1(T,n)=A(T)lnn+B(T)+C(T)n1/2lnn+??? as a function of temperature T and density n is obtained. Approximative expressions are given for the functions A(T), B(T), and C(T) in the quasiclassical limit, and the resulting conductivity is compared with experiments.

G. Röpke

1988-09-15T23:59:59.000Z

354

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

355

In situ Formation of Highly Conducting Covalent Au-C Contacts for Single-Molecule Junctions  

SciTech Connect (OSTI)

Charge transport across metal-molecule interfaces has an important role in organic electronics. Typically, chemical link groups such as thiols or amines are used to bind organic molecules to metal electrodes in single-molecule circuits, with these groups controlling both the physical structure and the electronic coupling at the interface. Direct metal-carbon coupling has been shown through C60, benzene and {pi}-stacked benzene but ideally the carbon backbone of the molecule should be covalently bonded to the electrode without intervening link groups. Here, we demonstrate a method to create junctions with such contacts. Trimethyl tin (SnMe{sub 3})-terminated polymethylene chains are used to form single-molecule junctions with a break-junction technique. Gold atoms at the electrode displace the SnMe{sub 3} linkers, leading to the formation of direct Au-C bonded single-molecule junctions with a conductance that is {approx}100 times larger than analogous alkanes with most other terminations. The conductance of these Au-C bonded alkanes decreases exponentially with molecular length, with a decay constant of 0.97 per methylene, consistent with a non-resonant transport mechanism. Control experiments and ab initio calculations show that high conductances are achieved because a covalent Au-C sigma ({sigma}) bond is formed. This offers a new method for making reproducible and highly conducting metal-organic contacts.

Cheng, Z.L.; Hybertsen, M.; Skouta, R.; Vazquez, H.; Widawsky, J.R.; Schneebeli, S.; Chen, W.; Breslow, R.; Venkataraman, L.

2011-06-01T23:59:59.000Z

356

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

357

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

358

Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters  

E-Print Network [OSTI]

Thermal Effects on Inverted Pendulum Thrust Stands for Steady-state High-power Plasma Thrusters A and Aerospace Engineering Department Princeton University, Princeton, New Jersey 08544 AIAA-2003-4842§ July 22, 2003 Abstract Thermal effects on direct measurements of the thrust produced by steady-state, high-power

Choueiri, Edgar

359

Thermal expansion of Mg(OH)2 brucite under high pressure and pressure dependence of entropy  

Science Journals Connector (OSTI)

An equation of state for Mg(OH)2 brucite under high-pressure and high-temperature conditions ... -ray diffraction. Pressure dependence of entropy of brucite has been calculated with thermal expansion coefficient....

H. Fukui; O. Ohtaka; T. Suzuki; K. Funakoshi

2003-10-01T23:59:59.000Z

360

Solar Thermal Energy Storage Device: Hybrid Nanostructures for High-Energy-Density Solar Thermal Fuels  

SciTech Connect (OSTI)

HEATS Project: MIT is developing a thermal energy storage device that captures energy from the sun; this energy can be stored and released at a later time when it is needed most. Within the device, the absorption of sunlight causes the solar thermal fuel’s photoactive molecules to change shape, which allows energy to be stored within their chemical bonds. A trigger is applied to release the stored energy as heat, where it can be converted into electricity or used directly as heat. The molecules would then revert to their original shape, and can be recharged using sunlight to begin the process anew. MIT’s technology would be 100% renewable, rechargeable like a battery, and emissions-free. Devices using these solar thermal fuels—called Hybrisol—can also be used without a grid infrastructure for applications such as de-icing, heating, cooking, and water purification.

None

2012-01-09T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

Latent Heat Based High Temperature Solar Thermal Energy Storage for Power Generation  

Science Journals Connector (OSTI)

Abstract The design of a phase change material based high temperature solar thermal energy storage device is presented. Said unit will be used as an energy reserve for a 1 kWe domestic CCHP system using a Stirling engine to produce electric power. The thermal energy storage is conducted by means of the exploitation of the latent heat of fusion of the material contained inside the tank. This method was chosen because a great energy density is obtained and, at the same time, it is possible to extract the stored energy with very small variations on the temperature, which is a favorable feature for its intended purpose. The selection of the phase change material is discussed and the design of the different components of the proposed storage model is described. It is analyzed, as well, the insulating solution applied that minimizes heat losses. Finally, a comparison between experimental results of the tests performed on the first built to scale prototype and the data obtained from computer simulations is shown.

Bruno Cárdenas; Noel León

2014-01-01T23:59:59.000Z

362

Effects of preheating and highly heat-conductive brick on coke quality  

SciTech Connect (OSTI)

In replacing the coke ovens available currently, the introduction of a combined technique of a preheated coal charging method (preheating temperature:175 C) and the use of highly heat-conductive brick is under examination for raising the productivity of coke ovens. With such background, a study of the effects of this combined technique on the coke quality, especially the coke size was conducted. The experimental results revealed that the primary size of coke produced by the combined technique is noticeably larger than that of the coke made from wet coal and after five revolutions of drum (equivalent to mechanical impact given at a time of dropping from coke oven chamber to wharf), the coke size reduces even compared with an ordinary coke. This may be due to the fact that the coke produced by the combined technique includes a lot of fissures inside the coke lump.

Fukuda, K.; Arima, T. [Nippon Steel Corp., Chiba (Japan). Process Technology, Research Labs.

1995-12-31T23:59:59.000Z

363

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.

364

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

E-Print Network [OSTI]

3 Fig. 1.2. Solar power plant operation [Materials for Concentrating Solar Power Plant Applications AMaterials for Concentrating Solar Power Plant Applications

Roshandell, Melina

2013-01-01T23:59:59.000Z

365

Using Coupled Mesoscale Experiments and Simulations to Investigate High Burn-Up Oxide Fuel Thermal Conductivity  

Science Journals Connector (OSTI)

Nuclear energy is a mature technology with a small carbon footprint. However, work is needed to make current reactor technology more accident tolerant and to allow reactor fuel to be burned in a reactor for longe...

Melissa C. Teague; Bradley S. Fromm; Michael R. Tonks; David P. Field

2014-10-01T23:59:59.000Z

366

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

E-Print Network [OSTI]

been heated at solar collection tower, at the temperatureIn the receiver tower, the collected solar radiation heatsfocus and send solar radiation to a receiver tower.

Roshandell, Melina

2013-01-01T23:59:59.000Z

367

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

E-Print Network [OSTI]

microencapsulation. Macroencapsulation means filling the PCMor plastic [6]. Macroencapsulation is very common becauseabilities. Also, macroencapsulation of CaCl 2 . 6 H 2 O in

Roshandell, Melina

2013-01-01T23:59:59.000Z

368

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

E-Print Network [OSTI]

for evening cooking in a solar cooker. Energy Convers Manageperformance of a solar cooker based on an evacuated tube

Roshandell, Melina

2013-01-01T23:59:59.000Z

369

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

370

On the Electric Conductivity of Highly Ordered Monolayers of Monodisperse Metal Nanoparticles  

Science Journals Connector (OSTI)

On the Electric Conductivity of Highly Ordered Monolayers of Monodisperse Metal Nanoparticles ... These observations are supported by finite element method calculations showing the self-capacitance to be the determining value which only depends on the permittivity constant of the surrounding space and the particles radius. ... In this paper we discuss the different transport properties of nanoparticle films and supercrystals which are governed in contrast to conventional crystals or metal films by the presence of tunnel barriers between the particles if the tunneling resistance Rt considerably exceeds the resistance quantum Rt ? h/e2 = 25.8 k?, with the Planck constant h and the elementary charge e. ...

Denis Greshnykh; Andreas Frömsdorf; Horst Weller; Christian Klinke

2008-12-22T23:59:59.000Z

371

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

372

Introduction When exposed to high thermal loads, many endotherms  

E-Print Network [OSTI]

ungulates, is heterothermy, the storage of body heat during the day, under positive thermal load the fact that the gradient between Tb and Ta was larger and solar radiation was lower in winter-1429 Published by The Company of Biologists 2006 doi:10.1242/jeb.02151 Heterothermy of free-living Arabian sand

Williams, Jos. B.

373

Design and Operation of Membrane Microcalorimeters for Thermal Screening of Highly Energetic Materials  

E-Print Network [OSTI]

thermal screening of an unknown sample may be used to determine the existence of an exothermic behavior. The relative thermal hazard of an unknown sample can be evaluated from information obtained from a thermal scan, which includes the position... of the exotherms, and its relative intensity and energy content. Sharp exotherms with relatively high area under 5 the peak, will be a sign of the possible presence of a HEM (i.e., explosives). On the other hand, insignificant exothermic behavior or its...

Carreto Vazquez, Victor 1976-

2010-12-07T23:59:59.000Z

374

Thermal Strategies for High Efficiency Thermoelectric Power Generation  

Broader source: Energy.gov [DOE]

Developing integrated TE system configurations that can achieve high heat exchange effectiveness and thus, high TE system efficiency

375

Optimizing Neutron Thermal Scattering Effects in very High Temperature Reactors  

SciTech Connect (OSTI)

This project aims to develop a holistic understanding of the phenomenon of neutron thermalization in the VHTR. Neutron thermaliation is dependent on the type and structure of the moderating material. The fact that the moderator (and reflector) in the VHTR is a solid material will introduce new and interesting considerations that do not apply in other (e.g. light water) reactors. The moderator structure is expected to undergo radiation induced changes as the irradiation (or burnup) history progresses. In this case, the induced changes in structure will have a direct impact on many properties including the neutronic behavior. This can be easily anticipated if one recognizes the dependence of neutron thermalization on the scattering law of the moderator. For the pebble bed reactor, it is anticipated that the moderating behavior can be tailored, e.g. using moderators that consist of composite materials, which could allow improved optimization of the moderator-to-fuel ratio.

Hawari, Ayman; Ougouag, Abderrafi

2014-07-08T23:59:59.000Z

376

Strong enhancement of light absorption and highly directive thermal emission in graphene  

E-Print Network [OSTI]

Strong enhancement of light absorption and highly directive thermal emission in graphene Mingbo Pu: Graphene is a two-dimensional material with exotic electronic, optical and thermal properties. The optical absorption in monolayer graphene is limited by the fine structure constant . Here we demonstrated the strong

Chen, Po

377

Design and global optimization of high-efficiency solar thermal systems  

E-Print Network [OSTI]

, Massachusetts 02139, USA bermel@mit.edu Abstract: Solar thermal, thermoelectric, and thermophotovoltaic (TPVDesign and global optimization of high-efficiency solar thermal systems with tungsten cermets DavidDepartment of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts

Soljaèiæ, Marin

378

High-index-contrast ridge waveguide laser with thermally oxidised etched facet and  

E-Print Network [OSTI]

). Laser ridges are then deeply etched, through the active region and into the lower cladding, usingHigh-index-contrast ridge waveguide laser with thermally oxidised etched facet and metal reflector heterostructure laser is demonstrated, which features an etched and wet thermally oxidised rear facet

379

High-speed thermal cycling system and method of use  

DOE Patents [OSTI]

A thermal cycling system and method of use are described. The thermal cycling system is based on the circulation of temperature-controlled water directly to the underside of thin-walled polycarbonate plates. The water flow is selected from a manifold fed by pumps from heated reservoirs. The plate wells are loaded with typically 15-20 microliters of reagent mix for the PCR process. Heat transfer through the thin polycarbonate is sufficiently rapid that the contents reach thermal equilibrium with the water in less than 15 seconds. Complete PCR amplification runs of 40 three-step cycles have been performed in as little as 14.5 minutes, with the results showing substantially enhanced specificity compared to conventional technology requiring run times in excess of 100 minutes. The plate clamping station is designed to be amenable to robotic loading and unloading of the system. It includes a heated lid, thus eliminating the need for mineral oil overlay of the reactants. The present system includes three or more plate holder stations, fed from common reservoirs but operating with independent switching cycles. The system can be modularly expanded. 13 figs.

Hansen, A.D.A.; Jaklevic, J.M.

1996-04-16T23:59:59.000Z

380

High-speed thermal cycling system and method of use  

DOE Patents [OSTI]

A thermal cycling system and method of use are described. The thermal cycling system is based on the-circulation of temperature-controlled water directly to the underside of thin-walled polycarbonate microtiter plates. The water flow is selected from a manifold fed by pumps from heated reservoirs. The plate wells are loaded with typically 15-20 .mu.l of reagent mix for the PCR process. Heat transfer through the thin polycarbonate is sufficiently rapid that the contents reach thermal equilibrium with the water in less than 15 seconds. Complete PCR amplification runs of 40 three-step cycles have been performed in as little as 14.5 minutes, with the results showing substantially enhanced specificity compared to conventional technology requiring run times in excess of 100 minutes. The plate clamping station is designed to be amenable to robotic loading and unloading of the system. It includes a heated lid, thus eliminating the need for mineral oil overlay of the reactants. The present system includes three or more plate holder stations, fed from common reservoirs but operating with independent switching cycles. The system can be modularly expanded.

Hansen, Anthony D. A. (Berkely, CA); Jaklevic, Joseph M. (Lafayette, CA)

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high 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

Flow and heat transfer in porous micro heat sink for thermal management of high power LEDs  

Science Journals Connector (OSTI)

A novel porous micro heat sink system is presented for thermal management of high power LEDs, which has high heat transport capability. The operational principle and heat transfer characteristics of porous micro heat sink are analyzed. Numerical model ... Keywords: Heat dissipation, High heat flux, High power LEDs, Porous media, Porous micro heat sink

Z. M. Wan; J. Liu; K. L. Su; X. H. Hu; S. S. M

2011-05-01T23:59:59.000Z

382

Modular High-Temperature Gas-Cooled Reactor short term thermal response to flow and reactivity transients  

SciTech Connect (OSTI)

The analyses reported here have been conducted at the Oak Ridge National Laboratory (ORNL) for the US Nuclear Regulatory Commission's (NRC's) Division of Regulatory Applications of the Office of Nuclear Regulatory Research. The short-term thermal response of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) is analyzed for a range of flow and reactivity transients. These include loss of forced circulation (LOFC) without scram, moisture ingress, spurious withdrawal of a control rod group, hypothetical large and rapid positive reactivity insertion, and a rapid core cooling event. The coupled heat transfer-neutron kinetics model is also described.

Cleveland, J.C.

1988-01-01T23:59:59.000Z

383

Handbook for Planning and Conducting Charrettes for High-Performance Projects  

SciTech Connect (OSTI)

The purpose of this handbook is to furnish guidance for planning and conducting a"high-performance building" charrette, sometimes called a"greening charrette." The handbook answers typical questions that will arise, such as"What is a charrette?""Why conduct a charrette?""What topics should we cover during the charrette?" and"Whom should we invite?" It also contains samples of agendas, invitation letters, and other commonly used charrette materials. This handbook also outlines the characteristics of a good charrette facilitator. It gives suggestions for the types of experts to invite to the event to motivate participants and answer their questions. The handbook includes sample presentations that can be used by these experts to ensure they address the required technical content. It suggests the types of participants, including technical, political, and community representatives, to invite to the charrette. It offers advice for forming effective breakout groups to ensure that a broad range of complementary expertise is represented in each group. We have also included guidance on how best to include key decision makers and stakeholders who are able to attend only portions of the event.

Lindsey, G.; Todd, J. A.; Hayter, S. J.

2003-08-01T23:59:59.000Z

384

Project Profile: High-Efficiency Thermal Storage System for Solar Plants  

Broader source: Energy.gov [DOE]

SENER, under the Baseload CSP FOA, aims to develop a highly efficient, low-maintenance and economical thermal energy storage (TES) system using solid graphite modular blocks for CSP plants.

385

Analysis of particle behavior in High-Velocity Oxy-Fuel thermal spraying process  

Science Journals Connector (OSTI)

This paper analyzes the behavior of coating particle as well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical...

Hiroshi Katanoda; Kazuyasu Matsuo

2003-08-01T23:59:59.000Z

386

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

387

A Handbook for Planning and Conducting Charrettes for High-Performance Projects, 2nd edition  

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

Operated by the Alliance for Sustainable Energy, LLC A Handbook for Planning and Conducting Charrettes for High-Performance Projects ii NOTICE 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 responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring

388

High figure-of-merit ultrathin metal transparent electrodes incorporating a conductive grid  

SciTech Connect (OSTI)

It is known that ultrathin (<10 nm) metal films (UTMFs) can achieve high level of optical transparency at the expense of the electrical sheet resistance. In this letter, we propose a design, the incorporation of an ad hoc conductive grid, which can significantly reduce the sheet resistance of UTMF based transparent electrodes, leaving practically unchanged their transparency. The calculated highest figure-of-merit corresponds to a filling factor and a grid spacing-to-linewidth ratio of 0.025 and 39, respectively. To demonstrate the capability of the proposed method the sheet resistance of a continuous 2 nm Ni film (>950 OMEGA/square) is reduced to approx6.5 OMEGA/square when a 100 nm thick Cu grid is deposited on it. The transparency is instead maintained at values exceeding 75%. These results, which can be further improved by making thicker grids, already demonstrate the potential in applications, such as photovoltaic cells, optical detectors and displays.

Ghosh, D. S.; Chen, T. L. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels, Barcelona, 08860 Catalunya (Spain); Pruneri, V. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Castelldefels, Barcelona, 08860 Catalunya (Spain); ICREA-Institucio Catalana de Recerca i Estudis Avancats, 08010 Barcelona (Spain)

2010-01-25T23:59:59.000Z

389

Highly conductive PEDOT:PSS on flexible substrate as ITO-free anode for polymer solar cells  

SciTech Connect (OSTI)

In this work, highly conductive anode based on PEDOT:PSS is proposed as substitute of Indio-Tin Oxide (ITO) in flexible solar cells. The anodic conductive polymer was spin coated on a 125 ?m thick polyethylene naphthalate (PEN) substrate. The obtained film was characterized in terms of structure and physical- chemical proprieties. The obtained results are very promising and the conductive film will be investigated in future as electrode in a complete polymeric solar cell.

Del Mauro, A. De Girolamo; Ricciardi, R.; Montanino, M.; Morvillo, P.; Minarini, C. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Portici Research Centre, p.le E. Fermi 1, 80055 Portici (Italy)

2014-05-15T23:59:59.000Z

390

Issues surrounding fracturing of geothermal systems - predicting thermal conductivity of reservoir rocks and evaluating performance of fracture proppants.  

E-Print Network [OSTI]

??Traditional geothermal systems have been limited to geologic systems in which elevated temperatures, abundant water, and high porosity and permeability are found. Engineered geothermal systems… (more)

Brinton, Daniel

2011-01-01T23:59:59.000Z

391

Highly Anisotropic Thermal Expansion in Molecular Films of Dicarboxylic Fatty Acids  

SciTech Connect (OSTI)

Angstrom-resolution x-ray measurements reveal the existence of two-dimensional (2D) crystalline order in molecularly thin films of surface-parallel-oriented fatty diacid molecules supported on a liquid mercury surface. The thermal expansion coefficients along the two unit cell vectors are found to differ 17-fold. The high anisotropy of the 2D thermal expansion and the crystalline coherence length are traced to the different bonding in the two directions: van der Waals normal to, and covalent plus hydrogen bonding along the molecular backbone axis. Similarities with, and differences from, negative thermal expansion materials are discussed.

Tamam L.; Ocko B.; Kraack, H.; Sloutskin, E.; Deutsch, M.

2012-05-25T23:59:59.000Z

392

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

393

Insights into CO poisoning in high performance proton-conducting solid oxide fuel cells  

Science Journals Connector (OSTI)

Abstract High performance anode supported proton-conducting solid oxide fuel cells (PC-SOFC) were fabricated and their performance in syngas was studied. PC-SOFC button cells produced a maximum power density of 812 mW cm?2 in H2 at 750 °C. It was found that the CO-containing feed streams could drastically degrade the performance of PC-SOFC. Based on the experimental results and the theoretical analysis, the detailed process of the CO-induced Ni catalyst deactivation was identified. This process could be divided into three distinguishable stages during the continuous exposure of the Ni catalyst in the CO-containing environment. The first stage could be described using the CO surface active site blocking mechanism, which was further confirmed by CO/H2 competitive adsorption model. The second stage deactivation was proposed to be related to the carbon deposition at TPB (Triple-phase Boundary). The deactivation during this stage was accelerated by the electrochemical conversion of H2. The last stage was attributed to the coking of Ni catalyst and the resulted metal dusting effect.

Ning Yan; Xian-Zhu Fu; Karl T. Chuang; Jing-Li Luo

2014-01-01T23:59:59.000Z

394

High conduction neutron absorber to simulate fast reactor environment in an existing test reactor  

SciTech Connect (OSTI)

A new metal matrix composite material has been developed to serve as a thermal neutron absorber for testing fast reactor fuels and materials in an existing pressurized water reactor. The performance of this material was evaluated by placing neutron fluence monitors within shrouded and unshrouded holders and irradiating for up to four cycles. The monitor wires were analyzed by gamma and X-ray spectrometry to determine the activities of the activation products. Adjusted neutron fluences were calculated and grouped into three bins—thermal, epithermal, and fast—to evaluate the spectral shift created by the new material. A comparison of shrouded and unshrouded fluence monitors shows a thermal fluence decrease of ~11 % for the shielded monitors. Radioisotope activity and mass for each of the major activation products is given to provide insight into the evolution of thermal absorption cross-section during irradiation. The thermal neutron absorption capability of the composite material appears to diminish at total neutron fluence levels of ~8 × 1025 n/m2. Calculated values for dpa in excess of 2.0 were obtained for two common structural materials (iron and nickel) of interest for future fast flux experiments.

Donna Post Guillen; Larry R. Greenwood; James R. Parry

2014-10-01T23:59:59.000Z

395

Highly conductive composites for fuel cell flow field plates and bipolar plates  

DOE Patents [OSTI]

This invention provides a fuel cell flow field plate or bipolar plate having flow channels on faces of the plate, comprising an electrically conductive polymer composite. The composite is composed of (A) at least 50% by weight of a conductive filler, comprising at least 5% by weight reinforcement fibers, expanded graphite platelets, graphitic nano-fibers, and/or carbon nano-tubes; (B) polymer matrix material at 1 to 49.9% by weight; and (C) a polymer binder at 0.1 to 10% by weight; wherein the sum of the conductive filler weight %, polymer matrix weight % and polymer binder weight % equals 100% and the bulk electrical conductivity of the flow field or bipolar plate is at least 100 S/cm. The invention also provides a continuous process for cost-effective mass production of the conductive composite-based flow field or bipolar plate.

Jang, Bor Z; Zhamu, Aruna; Song, Lulu

2014-10-21T23:59:59.000Z

396

Power efficiency for very high temperature solar thermal cavity receivers  

DOE Patents [OSTI]

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts infrared radiation from the front of the absorber. With this arrangement, a high percentage of the solar power input is retained in the cavity; thus, high internal temperatures are attained.

McDougal, Allan R. (LaCanada-Flintridge, CA); Hale, Robert R. (Upland, CA)

1984-01-01T23:59:59.000Z

397

Thermal properties of La2O3-doped ZrB2- and HfB2-based ultra-high temperature ceramics  

Science Journals Connector (OSTI)

Abstract Thermal properties of La2O3-doped ZrB2- and HfB2-based ultra high temperature ceramics (UHTCs) have been measured at temperatures from room temperature to 2000 °C and compared with SiC-doped ZrB2- and HfB2-based \\{UHTCs\\} and monolithic ZrB2 and HfB2. Thermal conductivities of La2O3-doped \\{UHTCs\\} remain constant around 55–60 W/mK from 1500 °C to 1900 °C while SiC-doped \\{UHTCs\\} showed a trend to decreasing values over this range.

E. Zapata-Solvas; D.D. Jayaseelan; P.M. Brown; W.E. Lee

2013-01-01T23:59:59.000Z

398

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

399

Third-order model of thermal conductivity for random polydisperse particulate materials using well-resolved statistical descriptions from tomography  

Science Journals Connector (OSTI)

Abstract For heterogeneous materials, obtaining an accurate statistical description has remained an outstanding problem. We accurately evaluate the three-point microstructural parameter that arises in third-order bounds and approximations of effective material properties. We propose new adaptive methods for computing n-point probability functions obtained from three-dimensional microstructures. We show that for highly packed systems our methods result in a 45% accuracy improvement compared to the latest techniques, and third-order approximations agree well with simulation data. Furthermore, third-order estimates of the effective behavior are computed for tomographically characterized systems of highly filled polydisperse ellipsoids and cuboids for the first time.

A. Gillman; K. Matouš

2014-01-01T23:59:59.000Z

400

Enhancement of specific heat capacity of high-temperature silica-nanofluids synthesized in alkali chloride salt eutectics for solar thermal-energy  

E-Print Network [OSTI]

chloride salt eutectics for solar thermal-energy storage applications Donghyun Shin, Debjyoti Banerjee for the anoma- lous enhancement of thermal conductivity over that of the neat solvent. Eastman et al. [5] reported thermal conductivity enhance- ment of 30% and 60% for water based nanofluids of Al2O3 and Cu

Banerjee, Debjyoti

Note: This page contains sample records for the topic "high 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

A High-Conduction Ge Substituted Li3AsS4 Solid Electrolyte with Exceptional Low Activation Energy  

SciTech Connect (OSTI)

Lithium-ion conducting solid electrolytes show potential to enable high-energy-density secondary batteries and offer distinctive safety features as an advantage over traditional liquid electrolytes. Achieving the combination of high ionic conductivity, low activation energy, and outstanding electrochemical stability in crystalline solid electrolytes is a challenge for the synthesis of novel solid electrolytes. Herein we report an exceptionally low activation energy (Ea) and high room temperature superionic conductivity via facile aliovalent substitution of Li3AsS4 by Ge, which increased the conductivity by two orders of magnitude as compared to the parent compound. The composition Li3.334Ge0.334As0.666S4 has a high ionic conductivity of 1.12 mScm-1 at 27oC. Local Li+ hopping in this material is accompanied by distinctive low activation energy Ea of 0.17 eV being the lowest of Li+ solid conductors. Furthermore, this study demonstrates the efficacy of surface passivation of solid electrolyte to achieve compatibility with metallic lithium electrodes.

Sahu, Gayatri [ORNL; Rangasamy, Ezhiylmurugan [ORNL; Li, Juchuan [ORNL; Chen, Yan [ORNL; An, Ke [ORNL; Dudney, Nancy J [ORNL; Liang, Chengdu [ORNL

2014-01-01T23:59:59.000Z

402

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

403

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

404

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.

405

Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines  

SciTech Connect (OSTI)

The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments – relative to traditional natural gas fired systems – affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive/thermo-chemical attack mechanisms; (iv) developing a mechanics-based analysis of the driving forces for crack growth and delamination, based on molten phase infiltration, misfit upon cooling, and loss of compliance; (v) understanding changes in TGO growth mechanisms associated with these emerging combustion product streams; and (vi) identifying degradation resistant alternative materials (including new compositions or bi-layer concepts) for use in mitigating the observed degradation modes. To address the materials stability concerns, this program integrated research thrusts aimed at: (1) Conducting tests in simulated syngas and HHC environments to evaluate materials evolution and degradation mechanisms; assessing thermally grown oxide development unique to HHC environmental exposures; carrying out high-resolution imaging and microanalysis to elucidate the evolution of surface deposits (molten phase formation and infiltration); exploring thermo-chemical instabilities; assessing thermo-mechanical drivers and thermal gradient effects on degradation; and quantitatively measuring stress evolution due to enhanced sintering and thermo-chemical instabilities induced in the coating. (2) Executing experiments to study the melting and infiltration of simulated ash deposits, and identifying reaction products and evolving phases associated with molten phase corrosion mechanisms; utilizing thermal spray techniques to fabricate test coupons with controlled microstructures to study mechanisms of instability and degradation; facilitating thermal gradient testing; and developing new materials systems for laboratory testing; (3) Correlating information on the resulting combustion environments to properly assess materials exposure conditions and guide the development of lab-scale simulations of material exposures; specification of representative syngas and high-hydrogen fuels with realistic levels of impurities and contaminants, to explore differences in heat transfer, surface degradation, and deposit formation; and facilitating combustion rig testing of materials test coupons.

Mumm, Daniel

2013-08-31T23:59:59.000Z

406

Nice, Cte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES  

E-Print Network [OSTI]

Nice, Côte d'Azur, France, 27-29 September 2006 THERMAL MODELING OF HIGH POWER LED MODULES D a study of accuracy issues in thermal modeling of high power LED modules on system level. Both physical dynamics (CFD) model of a high power LED module model at a reference application condition, and to validate

Paris-Sud XI, Université de

407

Thermal Activation of the High Explosive NTO: Sublimation, Decomposition, and Autocatalysis  

E-Print Network [OSTI]

Thermal Activation of the High Explosive NTO: Sublimation, Decomposition, and Autocatalysis Gregory of Chemistry, UniVersity of Utah, Salt Lake City, Utah 84112 ReceiVed: July 26, 2001; In Final Form: January 15 of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO) leads to competitive sublimation and condensed

Utah, University of

408

BEHAVIOUR OF A HIGHLY PRESSURISED TANK OF GHz, SUBMITTED TO A THERMAL OR MECHANICAL IMPACT  

E-Print Network [OSTI]

2000-41 BEHAVIOUR OF A HIGHLY PRESSURISED TANK OF GHz, SUBMITTED TO A THERMAL OR MECHANICAL IMPACT will significantly reduce the volume of the necessary tank(s). Whatever this pressure and whatever the volume of the tank(s), the storage System must be designed in such a way that the consequences of an accident

Paris-Sud XI, Université de

409

High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency thermal plasma  

E-Print Network [OSTI]

High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency Semiconductor, Eden Prairie, MN, USA Received 10 July 2002; accepted 14 July 2002 Abstract Silicon carbide films; Nanomaterials; Silicon carbide; Thermal plasmas; Thin films; Si tetrachlorine precursor Silicon carbide has

Zachariah, Michael R.

410

Origin of the zero-bias conductance peaks observed ubiquitously in high-T-c superconductors  

E-Print Network [OSTI]

principal axes orientations. They can Five rise to a zero-bias conductance peak (ZBCP) in quasiparticle tunneling along any axis as shown in our model calculation. When the counterelectrode is a low-T-c SC, its gap is shown to appear as a dip at the center...

Hu, Chia-Ren.

1998-01-01T23:59:59.000Z

411

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

412

A Flow-Through High-Pressure Electrical Conductance Cell for Determining of Ion Association of Aqueous Electrolyte Solutions at High Temperature and Pressure  

SciTech Connect (OSTI)

A flow-through high-pressure electrical conductance cell was designed and constructed to measure limiting molar conductances and ion association constants of dilute aqueous solutions with high precision at high temperatures and pressures. The basic concept of the cell employs the principle developed at the University of Delaware in 1995, but overall targets higher temperatures (to 600 C) and pressures (to 300 MPa). At present the cell has been tested by measuring aqueous NaCl and LiOH solutions (10{sup {minus}3} to 10{sup {minus}5} mol.kg{sup {minus}1}) to 405 C and 33 MPa with good results.

Bianchi, H.; Ho, P.C.; Palmer, D.A.; Wood, R.H.

1999-09-12T23:59:59.000Z

413

High-Frequency Conductivity of a Plasma in Quasi-Equilibrium. II. Effect of a Uniform Magnetic Field  

Science Journals Connector (OSTI)

A general expression for high-frequency conductivity is derived to include the effect of an external magnetic field. The limit of large ion mass is also discussed. For the special case that the unperturbed plasma is in thermodynamic equilibrium, the result obtained in the present paper reduces immediately to that previously discussed by Oberman and Shure.

Ching-Sheng Wu

1965-10-04T23:59:59.000Z

414

Soliton mechanism of the uranium nitride microdynamics and heat conductivity at high temperatures  

SciTech Connect (OSTI)

The microdynamics of soliton waves and localized modes of nonlinear acoustic and optical oscillations in uranium nitride has been investigated. It is shown that, upon heating, the energies of solitons in the gap between the optical and acoustic phonon bands increase, while the energies of local modes decrease. The experimentally observed quasi-resonance features, which are shifted in the gap with a change in temperature, can be manifestations of the revealed soliton waves and local modes. The microdynamics of uranium nitride heat conductivity with the stochastic generation of the observed solitons and local modes at remote energy absorption have been investigated. The temperature dependence of the heat conductivity coefficient has been determined from the temperature gradient and energy flux within the standard approach (which is to be generalized).

Semenov, V. A.; Dubovsky, O. A., E-mail: dubov@ippe.ru; Orlov, A. V. [State Scientific Center of the Russian Federation Leipunsky Institute for Physics and Power Engineering (Russian Federation)

2011-12-15T23:59:59.000Z

415

Experimental time-domain controlled source electromagnetic induction for highly conductive targets detection and discrimination  

E-Print Network [OSTI]

negative power of L. This is a basic description of a fractal (Mandelbrot, 1983). Topography and ore tonnage, for example, exhibit a fractal dimension (Turcotte, 1992). The same result is obtained for porosity in some sedimentary rocks (Katz and Thompson..., 1985). Recently, it has been shown that CSEM spatial profiles of apparent conductivity, using single frequency instruments, exhibit a power-law Fourier wavenumber spec- trum whose fractional exponent corresponds to a fractal (Everett and Weiss, 2002...

Benavides Iglesias, Alfonso

2007-09-17T23:59:59.000Z

416

Stable highly conductive ZnO via reduction of Zn vacancies. ...  

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

Instruments: Ultra-high Vacuum, Low-temperature Scanning Probe Microscope Instrument, or UHV LT SPM Tags: Nanoscope IIIa topographical nanostructures nanodevices oxides catalysis...

417

MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging  

E-Print Network [OSTI]

MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution potentials and the magnetic fields produced by the probing current are measured. Surface potentials are measured by using conventional electrical impedance tomography techniques and high resolution magnetic

Eyüboðlu, Murat

418

Efficient Heat Storage Materials: Metallic Composites Phase-Change Materials for High-Temperature Thermal Energy Storage  

SciTech Connect (OSTI)

HEATS Project: MIT is developing efficient heat storage materials for use in solar and nuclear power plants. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun’s not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. MIT is designing nanostructured heat storage materials that can store a large amount of heat per unit mass and volume. To do this, MIT is using phase change materials, which absorb a large amount of latent heat to melt from solid to liquid. MIT’s heat storage materials are designed to melt at high temperatures and conduct heat well—this makes them efficient at storing and releasing heat and enhances the overall efficiency of the thermal storage and energy-generation process. MIT’s low-cost heat storage materials also have a long life cycle, which further enhances their efficiency.

None

2011-11-21T23:59:59.000Z

419

Sapphire-conductive end-cooling of high power cryogenic Yb:YAG laser  

Science Journals Connector (OSTI)

We have demonstrated a high-power laser oscillator with end-cooling using a sapphire-sandwiched Yb:YAG disk at near liquid nitrogen temperature. An output power of 74 W with...

Tokita, Shigeki; Kawanaka, Junji; Izawa, Yasukazu; Fujita, Masayuki; Kawashima, Toshiyuki

420

Sapphire-Conductive End-Cooling of High Power Cryogenic Yb:YAG Laser  

Science Journals Connector (OSTI)

We have demonstrated a high-power laser oscillator with end-cooling using a sapphire-sandwiched Yb:YAG disk at liquid nitrogen temperature. An output power of 74 W with...

Tokita, Shigeki; Fujita, Masayuki; Kawanaka, Junji; Kawashima, Toshiyuki; Izawa, Yasukazu

Note: This page contains sample records for the topic "high 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

Measuring Frac-pack Conductivity at Reservoir Temperature and High Closure Stress  

E-Print Network [OSTI]

fractures packed with high proppant concentrations. Understanding the behavior of the fracture fluid and proppant is critical to pump such a job successfully and to ensure long term productivity from the fracture. A series of laboratory experiments have been...

Fernandes, Preston X.

2010-10-12T23:59:59.000Z

422

Thermal evaluation and performance of high-power Lithium-ion cells  

SciTech Connect (OSTI)

Under the sponsorship of the US Advanced Battery Consortium (USABC) and the Partnership for a New Generation of Vehicles (PNGV), Saft has developed high-power lithium-ion (Li-Ion) batteries for hybrid electric vehicles (HEVs). These high-power Li-Ion batteries are being evaluated for the US Department of Energy's (DOE) Hybrid Vehicle Propulsion Program. As part of this program, the National Renewable Energy Laboratory (NREL) characterized the thermal performance of the Saft (6-Ah) Li-Ion cells. The characterization included (1) obtaining thermal images of cells under a specified cycle, (2) measuring heat generation from the cells at various temperatures and under various charge/discharge profiles, and (3) determining the cells' capabilities for following a simulated power profile (driving cycle) at various initial states of charge and temperatures.

Keyser, M.; Pesaran, A.; Oweis, S.; Chagnon, G.; Ashtiani, C.

2000-01-25T23:59:59.000Z

423

Short time scale thermal mechanical shock wave propagation in high performance microelectronic packaging configuration  

E-Print Network [OSTI]

SHORT TIME SCALE THERMAL MECHANICAL SHOCK WAVE PROPAGATION IN HIGH PERFORMANCE MICROELECTRONIC PACKAGING CONFIGURATION A Thesis by MAHAVIR NAGARAJ Submitted to the Office of Graduate Studies of Texas A&M University... MICROELECTRONIC PACKAGING CONFIGURATION A Thesis by MAHAVIR NAGARAJ Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Chii...

Nagaraj, Mahavir

2004-11-15T23:59:59.000Z

424

Phase transitions, electrical conductivity and chemical stability of BiFeO{sub 3} at high temperatures  

SciTech Connect (OSTI)

The multiferroic perovskite BiFeO{sub 3} is reported to display two first order structural phase transitions. The structural phase transition at 925+-5 deg. C is demonstrated to be first order by calorimetry and dilatometry. Electrical conductivity measurements revealed that the high temperature phase above 925+-5 deg. C is semiconducting, in disagreement with recent reports. The sign and magnitude of the volumes of transition reflect the sign and magnitude of the discontinuities in electrical conductivity across the two first order phase transitions. A high partial pressure of oxygen was demonstrated to stabilise BiFeO{sub 3} towards peritectic decomposition. Finally, the origins of the commonly observed decomposition of BiFeO{sub 3} at high temperatures are discussed. - Graphical abstract: The structural phase transitions of multiferroic BiFeO{sub 3} are shown to first order, with discontinuous volume and electrical conductivity. Semiconductivity was found for all three polymorphs of BiFeO{sub 3}.

Selbach, Sverre M. [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Tybell, Thomas [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Einarsrud, Mari-Ann [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Grande, Tor, E-mail: tor.grande@material.ntnu.n [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

2010-05-15T23:59:59.000Z

425

High-Efficiency Energy Conversion in a Molecular Triad Connected to Conducting Leads Anatoly Yu. Smirnov,*,,  

E-Print Network [OSTI]

for Theoretical Physics, The UniVersity of Michigan, Ann Arbor, Michigan 48109-1040, and Department of Physics is highly attractive for solar cell applications. The large predicted increase in the efficiency, the efficient conversion of solar energy into chemical or electrical forms has attracted considerable attention

Nori, Franco

426

PERGAMON Carbon 39 (2001) 3944 Preparation of conductive carbons with high surface area  

E-Print Network [OSTI]

of graphitization) and Lc adsorption and desorption rates [1­3]. In many applica- (crystallite domain size), as well by Institute of Coal Chemistry, Chinese Academy Producing carbons with both structural order (high con. carbon filaments grown from methane gas using an iron- In this study, two methods were used to prepare

Chung, Deborah D.L.

427

High-Frequency Conductivity of a Plasma in Quasi-Equilibrium. III. Study of a Two-Temperature Plasma  

Science Journals Connector (OSTI)

A general expression for the high-frequency conductivity of a homogeneous, isotropic plasma is obtained. The derivation is based on the use of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy and therefore includes all effects due to the high-frequency field and the collective interactions up to first order in the plasma parameter. As an application of the general result, a two-temperature plasma with the electron temperature exceeding the ion temperature is studied in detail. It is found that when the ratio of the electron temperature to the ion temperature exceeds 100, there is an enhancement in the resistivity resulting from the excitation of incoherent ion waves.

E. H. Klevans and C. -S. Wu

1966-09-09T23:59:59.000Z

428

THE RELATIONSHIP BETWEEN EXTREME ULTRAVIOLET NON-THERMAL LINE BROADENING AND HIGH-ENERGY PARTICLES DURING SOLAR FLARES  

SciTech Connect (OSTI)

We have studied the relationship between the location of EUV non-thermal broadening and high-energy particles during large flares using the EUV Imaging Spectrometer on board Hinode, the Nobeyama Radio Polarimeter, the Nobeyama Radioheliograph, and the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory. We have analyzed five large flare events that contain thermal-rich, intermediate, and thermal-poor flares classified by the definition discussed in the paper. We found that, in the case of thermal-rich flares, the non-thermal broadening of Fe XXIV occurred at the top of the flaring loop at the beginning of the flares. The source of 17 GHz microwaves is located at the footpoint of the flare loop. On the other hand, in the case of intermediate/thermal-poor flares, the non-thermal broadening of Fe XXIV occurred at the footpoint of the flare loop at the beginning of the flares. The source of 17 GHz microwaves is located at the top of the flaring loop. We discussed the difference between thermal-rich and intermediate/thermal-poor flares based on the spatial information of non-thermal broadening, which may provide clues that the presence of turbulence plays an important role in the pitch angle scattering of high-energy electrons.

Kawate, T. [Kwasan and Hida Observatory, Kyoto University, Kurabashira, Kamitakaracho, Takayama, Gifu 506-1314 (Japan); Imada, S. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2013-10-01T23:59:59.000Z

429

Establishing Specifications for Low Enriched Uranium Fuel Operations Conducted Outside the High Flux Isotope Reactor Site  

SciTech Connect (OSTI)

The National Nuclear Security Administration (NNSA) has funded staff at Oak Ridge National Laboratory (ORNL) to study the conversion of the High Flux Isotope Reactor (HFIR) from the current, high enriched uranium fuel to low enriched uranium fuel. The LEU fuel form is a metal alloy that has never been used in HFIR or any HFIR-like reactor. This report provides documentation of a process for the creation of a fuel specification that will meet all applicable regulations and guidelines to which UT-Battelle, LLC (UTB) the operating contractor for ORNL - must adhere. This process will allow UTB to purchase LEU fuel for HFIR and be assured of the quality of the fuel being procured.

Pinkston, Daniel [ORNL; Primm, Trent [ORNL; Renfro, David G [ORNL; Sease, John D [ORNL

2010-10-01T23:59:59.000Z

430

STABLE HIGH CONDUCTIVITY BILAYERED ELECTROLYTES FOR LOW TEMPERATURE SOLID OXIDE FUEL CELLS  

SciTech Connect (OSTI)

A bilayer electrolyte consisting of acceptor-doped ceria (on the fuel/reducing side) and cubic-stabilized bismuth oxide (on the oxidizing side) was developed. The bilayer electrolyte that was developed showed significant improvement in open-circuit potential versus a typical ceria based SOFC. Moreover, the OCP of the bilayer cells increased as the thickness of the bismuth oxide layer increased relative to the ceria layer. Thereby, verifying the bilayer concept. Although, because of the absence of a suitable cathode (a problem we are still working assiduously to solve), we were unable to obtain power density curves, our modeling work predicts a reduction in electrolyte area specific resistance of two orders of magnitude over cubic-stabilized zirconia and projects a maximum power density of 9 W/m{sup 2} at 800 C and 0.09 W/m{sup 2} at 500 C. Towards the development of the bilayer electrolyte other significant strides were made. Among these were, first, the development of a, bismuth oxide based, oxide ion conductor with the highest conductivity (0.56 S/cm at 800 C and 0.043 S/cm at 500 C) known to date. Second, a physical model of the defect transport mechanisms and the driving forces for the ordering phenomena in bismuth oxide and other fluorite systems was developed. Third, a model for point defect transport in oxide mixed ionic-electronic conductors was developed, without the typical assumption of a uniform distribution of ions and including the effect of variable loads on the transport properties of an SOFC (with either a single or bilayer electrolyte).

Eric D. Wachsman; Keith L. Duncan

2002-09-30T23:59:59.000Z

431

Detection of surface impurity phases in high T.sub.C superconductors using thermally stimulated luminescence  

DOE Patents [OSTI]

Detection of surface impurity phases in high-temperature superconducting materials. Thermally stimulated luminescence has been found to occur in insulating impurity phases which commonly exist in high-temperature superconducting materials. The present invention is sensitive to impurity phases occurring at a level of less than 1% with a probe depth of about 1 .mu.m which is the region of interest for many superconductivity applications. Spectroscopic and spatial resolution of the emitted light from a sample permits identification and location of the impurity species. Absence of luminescence, and thus of insulating phases, can be correlated with low values of rf surface resistance.

Cooke, D. Wayne (Los Alamos, NM); Jahan, Muhammad S. (Bartlett, TN)

1989-01-01T23:59:59.000Z

432

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

433

RELAP5 model of the high flux isotope reactor with low enriched fuel thermal flux profiles  

SciTech Connect (OSTI)

The High Flux Isotope Reactor (HFIR) currently uses highly enriched uranium (HEU) fabricated into involute-shaped fuel plates. It is desired that HFIR be able to use low enriched uranium (LEU) fuel while preserving the current performance capability for its diverse missions in material irradiation studies, isotope production, and the use of neutron beam lines for basic research. Preliminary neutronics and depletion simulations of HFIR with LEU fuel have arrived to feasible fuel loadings that maintain the neutronics performance of the reactor. This article illustrates preliminary models developed for the analysis of the thermal-hydraulic characteristics of the LEU core to ensure safe operation of the reactor. The beginning of life (BOL) LEU thermal flux profile has been modeled in RELAP5 to facilitate steady state simulation of the core cooling, and of anticipated and unanticipated transients. Steady state results are presented to validate the new thermal power profile inputs. A power ramp, slow depressurization at the outlet, and flow coast down transients are also evaluated. (authors)

Banfield, J.; Mervin, B.; Hart, S.; Ritchie, J.; Walker, S.; Ruggles, A.; Maldonado, G. I. [Dept. of Nuclear Engineering, Univ. of Tennessee Knoxville, Knoxville, TN 37996-2300 (United States)

2012-07-01T23:59:59.000Z

434

Thermally insulated pipelines successfully move high-wax-content crude offshore Gabon  

SciTech Connect (OSTI)

Three thermally insulated pipelines have been installed at a water depth of 35 m (115 ft) in Shell Gabon's Lucina Marine field. The three lines consist of two 2-km (1.24-mile) long flowlines connecting drilling and production platforms and a 3.2 km (2 mile) long loading line connecting a production platform to a storage tanker permanently moored in the field. All three pipelines are of 10.75-in. OD with rigid polyurethane-foam insulation contained in a high-density polyethylene sleeve. The pipelines have been designed with an operating temperature of 90/degree/C. (194/degree/F.). Thermal insulation was chosen because of the Lucina crude's high wax cloud point of 55/degree/C. (131/degree/F.). Without insulation, cooling of the crude in subsea pipelines would have lead to rapid wax deposition. Details of the coating and insulation of the line and riser pipe are given. For the line pipe, a thermal-insulation system consisting of polyurethane foam (PUF) within a polyethylene (PE) sleeve pipe was chosen.

Hales, M.

1982-01-25T23:59:59.000Z

435

An example of remediation of mercury impacted soil using high vacuum low temperature thermal desorption  

SciTech Connect (OSTI)

The purpose of this paper is to describe a high vacuum, low temperature thermal desorption (LTTD) technology which has been used to remediate soil impacted with elemental mercury and to present the results of pre-treatment and post-treatment soil sampling. The general operating principles of this high vacuum LTTD technology, the IRHV-200, are: (a) depression of the boiling points of the target compounds by lowering the ambient pressure within the treatment chamber using a vacuum pump; (b) use of infrared radiation to generate a thermal gradient in the top several inches of non-liquid material contained within the treatment chamber and use of a carrier gas to transport the desorbed contaminants from the treatment chamber to a pollution control system. The overall effect of these parameters is a batch treatment system capable of desorbing target contaminants from soil under anaerobic conditions and low temperature such that the desorbed contaminants do not degrade and generate thermal or oxidative by-products. Essentially, the desorbed contaminants undergo a reversible phase change from liquid to vapor in the treatment chamber and are condensed back to liquid in the pollution control system. Results of bench top testing are compared to full scale remediations of significant volumes of soil to demonstrate remediation of mercury impacted soil. This technology is also applicable for soils impacted with other higher boiling point organics, such as, PCP, PCBs, PAHs, PNAs, pesticides and herbicides.

Dagdigian, J.V. [McLaren/Hart, Irvine, CA (United States)

1997-12-31T23:59:59.000Z

436

Development of high void fraction polylactide composite foams using injection molding: Mechanical and thermal insulation properties  

Science Journals Connector (OSTI)

Abstract Polylactide (PLA) and PLA composites with void fractions as high as 65% were fabricated using low-pressure foam injection molding (FIM) and high-pressure FIM (HPFIM) equipped with mold opening and gas counter pressure. The cellular morphology and crystallinity were characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The mechanical (flexural and impact resistance) and thermal insulation properties were also measured. Unlike, talc, the addition of nanoclay markedly enhanced the ductility of solid PLA samples as well as significantly improved the cell morphology of foamed samples, which resulted in the increased specific modulus, strength and impact resistance. In all the PLA samples made using HPFIM, with an increased void fraction up to 55%, the flexural rigidity increased up to four times, the specific impact resistance increased up to 15%, and the thermal insulation increased up to three times. The results of this investigation revealed that low-density PLA composite foams with improved rigidity, impact strength, and thermal insulation can be developed using HPFIM for various applications such as transportation and construction industries.

A. Ameli; D. Jahani; M. Nofar; P.U. Jung; C.B. Park

2014-01-01T23:59:59.000Z

437

Reactive wave growth in shock-compressed thermally degraded high explosives  

SciTech Connect (OSTI)

The authors have performed experiments to study the effect of thermal degradation on shock sensitivity and growth to detonation of several high-density plastic bonded explosives, confined in stainless steel cells. Assemblies were heated in situ in the target chamber of a light-gas gun. Confinement was varied to allow, in some cases, for thermal expansion of the explosive, and in other cases to vent the decomposition gases. Particle velocity profiles were measured using VISAR at a LiF window interface. Results for the IHE PBX-9502 showed that its sensitivity to shock initiation could be dramatically increased or decreased depending on the confinement conditions during heating. Effects were much less pronounced for PBX-9404 and PBX-9501.

Renlund, A.M.

1995-08-01T23:59:59.000Z

438

Reactive wave growth in shock-compressed thermally degraded high explosives  

Science Journals Connector (OSTI)

We have performed experiments to study the effect of thermal degradation on shock sensitivity and growth to detonation of several high-density plastic bonded explosives confined in stainless steel cells. Assemblies were heated in situ in the target chamber of a light-gas gun. Confinement was varied to allow in some cases for thermal expansion of the explosive and in other cases to vent the decomposition gases. Particle velocity profiles were measured using VISAR at a LiF window interface. Results for the IHE PBX-9502 showed that its sensitivity to shock initiation could be dramatically increased or decreased depending on the confinement conditions during heating. Effects were much less pronounced for PBX-9404 and PBX-9501.

Anita M. Renlund

1996-01-01T23:59:59.000Z

439

Reactive wave growth in shock-compressed thermally degraded high explosives  

SciTech Connect (OSTI)

We have performed experiments to study the effect of thermal degradation on shock sensitivity and growth to detonation of several high-density plastic bonded explosives, confined in stainless steel cells. Assemblies were heated {ital in situ} in the target chamber of a light-gas gun. Confinement was varied to allow, in some cases, for thermal expansion of the explosive, and in other cases to vent the decomposition gases. Particle velocity profiles were measured using VISAR at a LiF window interface. Results for the IHE PBX-9502 showed that its sensitivity to shock initiation could be dramatically increased or decreased depending on the confinement conditions during heating. Effects were much less pronounced for PBX-9404 and PBX-9501. {copyright} {ital 1996 American Institute of Physics.}

Renlund, A.M. [Sandia National Laboratories, P.O. Box 5800, MS 1454, Albuquerque, New Mexico 87185-1454 (United States)

1996-05-01T23:59:59.000Z

440

Wear 181-183 (1995) 66g-677 Thermal mounding in high speed dry sliders: experiment, theory  

E-Print Network [OSTI]

ELSEVIER WEAR Wear 181-183 (1995) 66g-677 Thermal mounding in high speed dry sliders: experiment, theory and comparison M.D. Bryant a, Jim-PO Wang a, JawWen Lin b aDepartment of Mechanical Engineering research involving severe wear via thermal mounding in dry sliders (carbon graphite on copper) is presented

Bryant, Michael D.

Note: This page contains sample records for the topic "high 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

Exergoeconomic analysis of high concentration photovoltaic thermal co-generation system for space cooling  

Science Journals Connector (OSTI)

Abstract This paper provides an exergetic analysis of a 10 MW high concentration photovoltaic thermal (HCPVT) power plant case study located in Hammam Bou Hadjar, Algeria. The novel HCPVT multi-energy carrier plant converts 25% of the direct normal irradiance (DNI) into electrical energy and 62.5% to low grade heat for a combined efficiency of 87.5%. The HCPVT system employs a point focus dish concentrator with a cooled PV receiver module. The novel “hot-water” cooling approach is used for energy reuse purposes and is enabled by our state-of-the-art substrate integrated micro-cooling technology. The high performance cooler of the receiver with a thermal resistance of <0.12 cm2 K/W enables the receiver module to handle concentrations of up to 5000 suns. In the present study, a concentration of 2000 suns allows using coolant fluid temperatures of up to 80 °C. This key innovation ensures reliable operation of the triple junction PV (3JPV) cells used and also allows heat recovery for utilization in other thermal applications such as space cooling, heating, and desalination. Within this context, an exergoeconomics analysis of photovoltaic thermal co-generation for space cooling is presented in this manuscript. The valuation method presented here for the HCPVT multi-energy carrier plant comprises both the technical and economic perspectives. The proposed model determines how the cost structure is evolving in four different scenarios by quantifying the potential thermal energy demand in Hammam Bou Hadjar. The model pins down the influence of technical details such as the exergetic efficiency to the economic value of the otherwise wasted heat. The thermal energy reuse boosts the power station?s overall yield, reduces total average costs and optimizes power supply as fixed capital is deployed more efficiently. It is observed that even though potential cooling demand can be substantial (19,490 MWh per household), prices for cooling should be 3 times lower than those of electricity in Algeria (18 USD/MWh) to be competitive. This implies a need to reach economies of scale in the production of individual key components of the HCPVT system. The net present value (NPV) is calculated taking growth rates and the system?s modular efficiencies into account, discounted over 25 years. Scenario 1 shows that even though Algeria currently has no market for thermal energy, a break-even quantity (49,728 MWh) can be deduced by taking into account the relation between fixed costs and the marginal profit. Scenario 2 focuses on the national growth rate needed to break even, i.e. +10.92%. Scenario 3 illustrates thermal price variations given an increase in the Coefficient of Performance (COP) of a thermally driven adsorption chiller after year 10. In this case, the price for cooling will decrease from 18 USD/MWh to 14 USD/MWh. Finally, scenario 4 depicts Hammam Bou Hadjar?s potential cooling demand per household and the growth rate needed to break even if a market for heat would exist.

Veronica Garcia-Heller; Stephan Paredes; Chin Lee Ong; Patrick Ruch; Bruno Michel

2014-01-01T23:59:59.000Z

442

Highly-Efficient Selective Metamaterial Absorber for High-Temperature Solar Thermal Energy Harvesting  

E-Print Network [OSTI]

In this work, a metamaterial selective solar absorber made of nanostructured titanium gratings deposited on an ultrathin MgF2 spacer and a tungsten ground film is proposed and experimentally demonstrated. Normal absorptance of the fabricated solar absorber is characterized to be higher than 90% in the UV, visible and, near infrared (IR) regime, while the mid-IR emittance is around 20%. The high broadband absorption in the solar spectrum is realized by the excitation of surface plasmon and magnetic polariton resonances, while the low mid-IR emittance is due to the highly reflective nature of the metallic components. Further directional and polarized reflectance measurements show wide-angle and polarization-insensitive high absorption within solar spectrum. Temperature-dependent spectroscopic characterization indicates that the optical properties barely change at elevated temperatures up to 350{\\deg}C. The solar-to-heat conversion efficiency with the fabricated metamaterial solar absorber is predicted to be 78%...

Wang, Hao; Mitchell, Arnan; Rosengarten, Gary; Phelan, Patrick; Wang, Liping

2014-01-01T23:59:59.000Z

443

High resolution, low cost, privacy preserving human motion tracking system via passive thermal sensing  

E-Print Network [OSTI]

Thermal imaging is powerful but expensive. This thesis presents an alternative thermal sensing system capable of tracking human motion by using a novel projection mechanism from an array of inexpensive single-bit thermal ...

Browarek, Sharmeen

2010-01-01T23:59:59.000Z

444

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

445

Electrical-Thermal-Structural Coupled Finite Element Model of High Temperature Superconductor for Resistive Type Fault Current Limiters  

Science Journals Connector (OSTI)

A multi-physics finite element model of high-temperature superconductors (HTS) will be presented in this article. The electrical-thermal model is mainly based on Maxwell’s equation and basic heat transfer equa...

J. Sheng; Y. Chen; B. Lin; L. Ying; Z. Jin…

2014-06-01T23:59:59.000Z

446

Numerical modeling of in-flight characteristics of inconel 625 particles during high-velocity oxy-fuel thermal spraying  

Science Journals Connector (OSTI)

A computational fluid dynamics (CFD) model is developed to predict particle dynamic behavior in a high-velocity oxyfuel (HVOF) thermal spray gun in which premixed oxygen and propylene are ... 20 to 40 µm. At a pa...

S. Gu; D. G. McCartney; C. N. Eastwick; K. Simmons

2004-01-01T23:59:59.000Z

447

Thermal impact of waste emplacement and surface cooling associated with geologic disposal of high-level nuclear waste  

Science Journals Connector (OSTI)

This article is a study of the thermal effects associated with the emplacement of aged radioactive high-level wastes in a geologic repository, with emphasis on the following subjects: waste characteristics, re...

J. S. Y. Wang; D. C. Mangold; C. F. Tsang

1988-04-01T23:59:59.000Z

448

High resolution numerical study of Rayleigh-Taylor turbulence using a thermal lattice Boltzmann scheme  

E-Print Network [OSTI]

We present results of a high resolution numerical study of two dimensional (2d) Rayleigh-Taylor turbulence using a recently proposed thermal lattice Boltzmann method (LBT). The goal of our study is both methodological and physical. We assess merits and limitations concerning small- and large-scale resolution/accuracy of the adopted integration scheme. We discuss quantitatively the requirements needed to keep the method stable and precise enough to simulate stratified and unstratified flows driven by thermal active fluctuations at high Rayleigh and high Reynolds numbers. We present data with spatial resolution up to 4096 x 10000 grid points and Rayleigh number up to Ra ~ 10^11 . The statistical quality of the data allows us to investigate velocity and temperature fluctuations, scale-by-scale, over roughly four decades. We present a detailed quantitative analysis of scaling laws in the viscous, inertial and integral range, supporting the existence of a Bolgiano-like inertial scaling, as expected in 2d systems. We also discuss the presence of small/large intermittent deviation to the scaling of velocity/temperature fluctuations and the Rayleigh dependency of gradients flatness.

L. Biferale; F. Mantovani; M. Sbragaglia; A. Scagliarini; F. Toschi; R. Tripiccione

2010-09-28T23:59:59.000Z

449

Effect of Ca Doping on the Electrical Conductivity of the High-Temperature Proton Conductor LaNbO4  

SciTech Connect (OSTI)

The sintering properties, crystal structure and electrical conductivity of La1-xCaxNbO4- (x=0, 0.005, 0.01, 0.015, 0.02 and 0.025), prepared by a conventional solid-state method, have been investigated using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). In 2.5% Ca doped samples, a small amount of impurities Ca2Nb2O7 were observed from the XRD patterns. Impedance spectra show that the grain boundary resistance increases with increasing Ca content, while the bulk resistance remains essentially constant below 550 C. Despite the higher degree of grain growth was observed for higher Ca-doping levels, the total conductivity of the La1-xCaxNbO4- series decreases with increasing Ca content from 0.5 to 2.0 mol%. The activation energy for the total conductivity decreases with increasing Ca content from 0.71 eV (x=0) to 0.54 eV (x=0.01) for the high temperature tetragonal phase, then it increases to 0.60 eV for x=0.02. For the monoclinic phase, La0.995Ca0.005NbO4- shows the lowest activation energy of 1.26 eV. These results imply that the solubility of CaO in LaNbO4 is in the range from 0.5 to 1.0 mol%. By increasing the sintering temperature from 1500 C to 1550 C, the proton conductivity of the Ca-doped LaNbO4 was improved with enlarged grain size due to a reduction in the resistive grain boundary contribution.

Bi, Zhonghe [ORNL; Pena-Martinez, Juan [ORNL; Kim, Jung-Hyun [ORNL; Bridges, Craig A [ORNL; Huq, Ashfia [ORNL; Hodges, Jason P [ORNL; Paranthaman, Mariappan Parans [ORNL

2012-01-01T23:59:59.000Z

450

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

451

Conductivity of Hg{sub 3}In{sub 2}Te{sub 6} crystals in high electric fields  

SciTech Connect (OSTI)

The effect of electric field and temperature on the conductivity of bulk Hg{sub 3}In{sub 2}Te{sub 6} crystals is investigated. It is shown that the I-V characteristics in high electric fields are of the S type with the effect of switching into a low-resistance state. The critical voltage of transition from the Ohm law to the exponential dependence of the current (I) on the voltage (U) and the threshold voltage of transition into the region of negative differential resistance dU/dI = s< 0 linearly depend on the sample thickness. The activation energies of conductivity in low and high electric fields are determined. It is established that the superlinear portion of the I-V characteristic with dU/dI > 0 is described by the dependence of the type I = I{sub 0} exp(U/U{sub 0}) and caused by the electron transitions from the local centers with the energy level E{sub t} = 0.19 eV.

Grushka, O. G., E-mail: semicon-dpt@chnu.edu.ua; Chupyra, S. M.; Myslyuk, O. M.; Bilichuk, S. V.; Zabolotsky, I. I. [Fedkovich Chernovtsy National University (Ukraine)

2011-01-15T23:59:59.000Z

452

High Temperature Oxidation Resistance and Surface Electrical...  

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

plates with oxidation resistant coatings. Candidate coatings must exhibit chemical and thermal-mechanical stability and high electrical conductivity during long-term...

453

Evaluation of annual efficiencies of high temperature central receiver concentrated solar power plants with thermal energy storage.  

SciTech Connect (OSTI)

The current study has examined four cases of a central receiver concentrated solar power plant with thermal energy storage using the DELSOL and SOLERGY computer codes. The current state-of-the-art base case was compared with a theoretical high temperature case which was based on the scaling of some input parameters and the estimation of other parameters based on performance targets from the Department of Energy SunShot Initiative. This comparison was done for both current and high temperature cases in two configurations: a surround field with an external cylindrical receiver and a north field with a single cavity receiver. There is a fairly dramatic difference between the design point and annual average performance, especially in the solar field and receiver subsystems, and also in energy losses due to the thermal energy storage being full to capacity. Additionally, there are relatively small differences (<2%) in annual average efficiencies between the Base and High Temperature cases, despite an increase in thermal to electric conversion efficiency of over 8%. This is due the increased thermal losses at higher temperature and operational losses due to subsystem start-up and shut-down. Thermal energy storage can mitigate some of these losses by utilizing larger thermal energy storage to ensure that the electric power production system does not need to stop and re-start as often, but solar energy is inherently transient. Economic and cost considerations were not considered here, but will have a significant impact on solar thermal electric power production strategy and sizing.

Ehrhart, Brian David; Gill, David Dennis

2013-07-01T23:59:59.000Z

454

Production of high-V. I. oils by thermal decomposition of ethylene/propylene copolymer  

SciTech Connect (OSTI)

The process of copolymerization of ethylene with propylene can be readily controlled, so that copolymers with practically any desired composition can be obtained, with a specific alternation of monomer units and with a specific number of lateral branches. This paper examines the preparation of high-V.I. synthetic lube oils by the thermal decomposition of an ethylene/propylene copolymer with a molecular weight of 100,000-1,000,000, containing 40-85% (mole) ethylene, synthesized on ZieglerNatta organometallic systems. It determines the distillation curve, and the physicochemical and service properties of the distillation cuts. It finds that the oils have high viscosity indices, low solid points, and good oxidation resistance and anticorrosion properties. These oils can be used in vehicles and mechanisms operating in the Far North and in the Arctic.

Seidov, N.M.; Abasov, A.I.; Abasova, T.M.; Bairamov, V.A.; Kuliev, R.Sh.; Mustafaev, A.M.

1982-09-01T23:59:59.000Z

455

The effects of atomic oxygen on the thermal emittance of high temperature radiator surfaces  

SciTech Connect (OSTI)

Radiator surfaces on high temperature space power systems such as the SP-100 space nuclear power system must maintain a high emittance level in order to reject waste heat effectively. one of the primary materials under consideration for the radiators is carbon-carbon composite. Since carbon is susceptible to attack by atomic oxygen in the low Earth orbital environment, it is important to determine the durability of carbon composites in this environment as well as the effect atomic oxygen has on the thermal emittance of the surface if it is to be considered for use as a radiator. Results indicate that the thermal emittance of carbon-carbon composite (as low as 0.42) can be enhanced by exposure to a directed beam of atomic oxygen to levels above 0.85 at 800 K. This emittance enhancement is due to a change in the surface morphology as a result of oxidation. High aspect ratio cones are formed on the surface which allow more efficient trapping of incident radiation. Erosion of the surface due to oxidation is similar to that for carbon; so that at altitudes less than {approximately}600 km, thickness loss of the radiator could be significant (as much as 0.1 cm/year). A protective coating or oxidation barrier forming additive may be needed to prevent atomic oxygen attack after the initial high emittance surface is formed. Textured surfaces can be formed in ground based facilities or possibly in space if emittance is not sensitive to the orientation of the atomic oxygen arrival that forms the texture.

Rutledge, S.K. [Lewis Research Center, Cleveland, OH (United States); Hotes, D.L.; Paulsen, P.E. [Cleveland State Univ., OH (United States)

1994-09-01T23:59:59.000Z

456

Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate  

DOE Patents [OSTI]

This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.sup.2.

Jang, Bor Z. (Centerville, OH); Zhamu, Aruna (Centerville, OH); Guo, Jiusheng (Centerville, OH)

2011-02-15T23:59:59.000Z

457

Non-thermal high-energy emission from colliding winds of massive stars  

E-Print Network [OSTI]

Colliding winds of massive star binary systems are considered as potential sites of non-thermal high-energy photon production. This is motivated merely by the detection of synchrotron radio emission from the expected colliding wind location. Here we investigate the properties of high-energy photon production in colliding winds of long-period WR+OB-systems. We found that in the dominating leptonic radiation process anisotropy and Klein-Nishina effects may yield spectral and variability signatures in the gamma-ray domain at or above the sensitivity of current or upcoming gamma-ray telescopes. Analytical formulae for the steady-state particle spectra are derived assuming diffusive particle acceleration out of a pool of thermal wind particles, and taking into account adiabatic and all relevant radiative losses. For the first time we include their advection/convection in the wind collision zone, and distinguish two regions within this extended region: the acceleration region where spatial diffusion is superior to convective/advective motion, and the convection region defined by the convection time shorter than the diffusion time scale. The calculation of the Inverse Compton radiation uses the full Klein-Nishina cross section, and takes into account the anisotropic nature of the scattering process. This leads to orbital flux variations by up to several orders of magnitude which may, however, be blurred by the geometry of the system. The calculations are applied to the typical WR+OB-systems WR 140 and WR 147 to yield predictions of their expected spectral and temporal characteristica and to evaluate chances to detect high-energy emission with the current and upcoming gamma-ray experiments. (abridged)

A. Reimer; M. Pohl; O. Reimer

2005-10-25T23:59:59.000Z

458

Temperature Instability in High-Tc Superconducting Wire Exposed to Thermal Disturbance  

Science Journals Connector (OSTI)

Abstract High-Tc superconductor wires/ conductors of longer lengths have emerged as one of the most promising candidates for several useful applications such as in utilities and in current lead powering large magnet system. These conductors are liquid nitrogen cooled and are much cheaper to operate. In the event of intrinsic thermal instability or cooling failure, irreversible transition to normal state may occur. These normal zones may propagate rapidly enough to cause transient heating leading to local ‘hot spot’ and resulting in damage to the conductor/ magnet. In this paper, the mathematical formulation to determine the temperature distribution throughout the superconductor wire subjected to such transient disturbance is illustrated. The solution to the problem is achieved by using the method of separation of variables based on physically relevant initial conditions. The results are obtained in the series form in terms of Bessel's functions and are illustrated numerically for a technical yttrium barium copper oxide (YBCO) superconductor wire. Also it is found that even for a steady state heat transfer of 500 W m–2 K–1, the conductor temperature rises above Tc in less than 10 sec of the thermal disturbance.

Ziauddin Khan; Subrata Pradhan; Irfan Ahmed

2014-01-01T23:59:59.000Z

459

Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams  

SciTech Connect (OSTI)

The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; /SLAC; Bentsen, G.S.; /Rochester U.

2011-12-13T23:59:59.000Z

460

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

Note: This page contains sample records for the topic "high 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 optimization of high power LED arrays with a fin cooling system  

Science Journals Connector (OSTI)

In this paper, we describe an optimization process of thermal design for the light lamp which utilizes the Light Emitting Diode (LED) module as a lighting source. The thermal performance of the LED module was sho...

Sun Ho Jang; Moo Whan Shin

2011-10-01T23:59:59.000Z

462

Sodium sulfate–diatomite composite materials for high temperature thermal energy storage  

Science Journals Connector (OSTI)

Abstract This work explores the use of sodium sulfate and diatomite to formulate composite materials for high temperature thermal energy storage applications. Sodium sulfate in the composite functions as a phase change material (PCM) and diatomite as a structural skeleton for shape stabilization. It is found that sodium sulfate and diatomite have an excellent chemical compatibility with the PCM melting temperature at around 880 °C. It is shown that the composite containing 45% diatomite gives an optimal formulation in terms of energy density, salt leakage and mechanical strength. The results also suggest that the composite with the optimal formulation has an application window of 890–980 °C. Failures occur to the composite materials at temperatures above 1000 °C.

Yue Qin; Guanghui Leng; Xiang Yu; Hui Cao; Geng Qiao; Yunfeng Dai; Yelong Zhang; Yulong Ding

2014-01-01T23:59:59.000Z

463

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

464

Thermal behavior of nickel–metal hydride battery during charging at a wide range of ambient temperatures  

Science Journals Connector (OSTI)

The thermal behavior of D-type Ni–MH battery during charging was investigated at a wide ... this work. The temperature measurement of the battery was conducted by using a thermal infrared imager put in a high–low...

Kai Zheng Fang; Dao Bin Mu; Shi Chen…

2011-07-01T23:59:59.000Z

465

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

466

High thermal stability and low Gilbert damping constant of CoFeB/MgO bilayer with perpendicular magnetic anisotropy by Al capping and rapid thermal annealing  

SciTech Connect (OSTI)

We demonstrate that the magnetic anisotropy of the CoFeB/MgO bilayer can be manipulated by adding an aluminum capping layer. After rapid thermal annealing, we can achieve large perpendicular magnetic anisotropy of CoFeB with a high thermal stability factor (??=?72) while the Gilbert damping constant can be reduced down to only 0.011 simultaneously. The boron and residual oxygen in the bulk CoFeB layer are properly absorbed by the Al capping layer during annealing, leading to the enhanced exchange stiffness and reduced damping. The interfacial Fe-O bonding can be optimized by tuning annealing temperature and thickness of Al, resulting in enhanced perpendicular anisotropy.

Wang, Ding-Shuo; Lai, Shu-Yu; Lin, Tzu-Ying; Wang, Liang-Wei; Liao, Jung-Wei; Lai, Chih-Huang, E-mail: chlai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Chien, Cheng-Wei; Wang, Yung-Hung [Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Chutung, Taiwan (China); Ellsworth, David; Lu, Lei; Wu, Mingzhong [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

2014-04-07T23:59:59.000Z

467

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

468

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

469

Sintering and properties of Ultra High Temperature Ceramics for aerospace applications J.F. Justin  

E-Print Network [OSTI]

thermal shock resistance and makes them ideal for many high-temperature thermal applications : France (2013)" #12;for example, a high thermal conductivity reduces thermal stress within the material-francois.justin@onera.fr ABSTRACT The Ultra High Temperature Ceramics (UHTCs) represent a very interesting family of materials

470

Thermal Barrier Coatings Chemically and Mechanically Resistant to High Temperature Attack by Molten Ashes.  

E-Print Network [OSTI]

?? Thermal barrier coatings (TBCs) are ceramic coatings used on component in the hottest sections of gas turbine engines, used for power generation and aviation.… (more)

Gledhill, Andrew Dean

2011-01-01T23:59:59.000Z

471

Encapsulation of High Temperature Phase Change Materials for Thermal Energy Storage.  

E-Print Network [OSTI]

??Thermal energy storage is a major contributor to bridge the gap between energy demand (consumption) and energy production (supply) by concentrating solar power. The utilization… (more)

Nath, Rupa

2012-01-01T23:59:59.000Z

472

Modeling and Control of High-Velocity Oxygen-Fuel (HVOF) Thermal Spray: A Tutorial Review  

E-Print Network [OSTI]

vs. Fuzzy Logic: Simple Tools to Predict and Control Complexfuzzy logic (Ref 73, 74). For the HVOF thermal spray process, a feedback control

Li, Mingheng; Christofides, Panagiotis D.

2009-01-01T23:59:59.000Z

473

High Temperature InGaN Topping Cells for Hybrid Photovoltaic/Concentrating Solar Thermal Systems  

Science Journals Connector (OSTI)

Hybrid PV/CSP systems offer the potential of higher solar to grid efficiency, with the benefits of dispatchable electricity from thermal storage. Here we present an implementation...

Honsberg, Christiana; Gleckman, Philip; Doolittle, William A; Ponce, Fernando; Arena, Chantal; Vasileska, Dragica; Goodnick, Stephen M

474

Electrical and Thermal Transport Optimization of High Efficient n-type Skutterudites  

Broader source: Energy.gov [DOE]

Work on optimizing electrical and thermal transport properties of n-type skutterudites via a multiple-element-void-filling approach is presented.

475

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

476

Thermal treatment of high explosives at Mason & Hanger/Pantex Plant  

SciTech Connect (OSTI)

The Pantex plant presently processes about 45,000 kg (100,000 lb) of high explosives annually by outdoor burning. About half of the explosives are weapon components weighing over 5 kg (10 lb) which come directly out of nuclear weapons being removed from the stockpile. The other half is generated from various support processes, special tests, etc. Burning serves the three-fold purpose of demilitarizing, removing all classified characteristics, and eliminating the severe hazard posed by the explosives themselves. Transporting such large quantities of classified high explosives for such processing at another site would be prohibitive. Computerized atmospheric modelling of the burning process was conducted during the past year. The results were somewhat surprising in that oxides of nitrogen and carbon monoxide, two ``criteria pollutants,`` were not of great concern even though it is known that high explosives contain significant amounts of nitrogen and they generate measureable amounts of carbon monoxide when they are burned. Rather, it was determined that hydrogen fluoride gas is of much greater concern, and stringent controls on the burning operation have been implemented to address this concern. Although the amount of fluorine-containing explosive must be restricted, other kinds of air emissions are not a great concern. This favorable situation is largely due to the flat, featureless, sparsely inhabited terrain, the distance to the nearest plant boundary, the wind, the lack of stagnant atmospheric conditions, and the tremendous rate of heat release.

Patterson, W.E.; Phelan, P.F.

1993-12-31T23:59:59.000Z

477

A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays Final Technical Report  

SciTech Connect (OSTI)

This is the final technical report for the SBIR Phase I project titled 'A System for Conducting Sophisticated Mechanical Tests in Situ with High Energy Synchrotron X-Rays.' Experiments using diffraction of synchrotron radiation that help scientists understand engineering material failure modes, such as fracture and fatigue, require specialized machinery. This machinery must be able to induce these failure modes in a material specimen while adhering to strict size, weight, and geometric limitations prescribed by diffraction measurement techniques. During this Phase I project, Mechanical Solutions, Inc. (MSI) developed one such machine capable of applying uniaxial mechanical loading to a material specimen in both tension and compression, with zero backlash while transitioning between the two. Engineers currently compensate for a lack of understanding of fracture and fatigue by employing factors of safety in crucial system components. Thus, mechanical and structural parts are several times bigger, thicker, and heavier than they need to be. The scientific discoveries that result from diffraction experiments which utilize sophisticated mechanical loading devices will allow for broad material, weight, fuel, and cost savings in engineering design across all industries, while reducing the number of catastrophic failures in transportation, power generation, infrastructure, and all other engineering systems. With an existing load frame as the starting point, the research focused on two main areas: (1) the design of a specimen alignment and gripping system that enables pure uniaxial tension and compression loading (and no bending, shear, or torsion), and (2) development of a feedback control system that is adaptive and thus can maintain a load set point despite changing specimen material properties (e.g. a dec