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Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

2

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

3

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.

4

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

5

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

6

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

SciTech Connect

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

7

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

SciTech Connect

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

8

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

9

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

10

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

SciTech Connect

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

11

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

12

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

SciTech Connect

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

13

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

SciTech Connect

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

14

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

15

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

16

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

17

Enhanced Thermal Conductivity Oxide Fuels  

SciTech Connect

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

18

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

SciTech Connect

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

19

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

SciTech Connect

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

20

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

22

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

23

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

24

Measurement of the electronic thermal conductance channels and heat capacity of graphene at low temperature  

E-Print Network (OSTI)

opto-electronics, plasmonics, and ultra-sensitive bolometry. Here we present measurements of bipolar con- ductance over a temperature range of 300 mK to 100 K, using three different sample configurations of 10-20 J/K at 300 mK, which is 9 times smaller than the previous record[15]. For higher temperatures

25

Continuous Processing of High Thermal Conductivity Polyethylene...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

26

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

27

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

28

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

29

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

30

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.

31

Los Alamos probes mysteries of uranium dioxide's thermal conductivity  

NLE Websites -- All DOE Office Websites (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...

32

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

33

Enhancing Thermal Conductivity and Reducing Friction  

NLE Websites -- All DOE Office Websites (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

34

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.

35

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.

36

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

37

Final Report: Thermal Conductance of Solid-Liquid Interfaces  

SciTech Connect

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

38

Thermomechanical measurements on thermal microactuators.  

SciTech Connect

Due to the coupling of thermal and mechanical behaviors at small scales, a Campaign 6 project was created to investigate thermomechanical phenomena in microsystems. This report documents experimental measurements conducted under the auspices of this project. Since thermal and mechanical measurements for thermal microactuators were not available for a single microactuator design, a comprehensive suite of thermal and mechanical experimental data was taken and compiled for model validation purposes. Three thermal microactuator designs were selected and fabricated using the SUMMiT V{sup TM} process at Sandia National Laboratories. Thermal and mechanical measurements for the bent-beam polycrystalline silicon thermal microactuators are reported, including displacement, overall actuator electrical resistance, force, temperature profiles along microactuator legs in standard laboratory air pressures and reduced pressures down to 50 mTorr, resonant frequency, out-of-plane displacement, and dynamic displacement response to applied voltages.

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

2009-01-01T23:59:59.000Z

39

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

40

Electrical and thermal conductivities in dense plasmas  

SciTech Connect

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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 in Nanocrystalline Ceria Thin Films  

SciTech Connect

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

42

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

43

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

44

Continuous Processing of High Thermal Conductivity Fibers and...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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...

45

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

46

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

47

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.

48

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

49

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

50

Thermal conductivity of Permian Basin bedded salt at elevated pressure  

SciTech Connect

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

51

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

52

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

53

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

54

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

55

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.

56

The thermal conductivity of silicon nitride with molybdenum disilicide additions  

SciTech Connect

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

57

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

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

58

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

SciTech Connect

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

59

Report on workshop on thermal property measurements  

SciTech Connect

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

60

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

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


61

Thermal conductivity of graphene nanoribbons in noble gaseous environments  

SciTech Connect

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

62

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

63

Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets  

Energy.gov (U.S. Department of Energy (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.

64

Glass-like thermal conductivity in high efficiency thermoelectric materials  

Energy.gov (U.S. Department of Energy (DOE))

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

65

Conductivity measurement on thick insulating plaque samples.  

E-Print Network (OSTI)

?? The conductivity is one of the main properties of HVDC cable insulation materials and needs to be evaluated carefully. Since measurement on cables is… (more)

Huldén, Pierre

2014-01-01T23:59:59.000Z

66

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

SciTech Connect

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

67

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

68

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

69

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

70

Reduction of Thermal Conductivity in Wafer-Bonded Silicon  

SciTech Connect

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

71

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

SciTech Connect

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

72

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

73

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

74

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

75

Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites  

SciTech Connect

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

76

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

SciTech Connect

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

77

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

78

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

79

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

SciTech Connect

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

80

Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives  

SciTech Connect

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

82

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

83

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

84

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

85

Mode dependent lattice thermal conductivity of single layer graphene  

SciTech Connect

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

86

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

87

Effective thermal conductivity for anisotropic granular porous media using fractal concepts  

SciTech Connect

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

88

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

89

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

90

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

91

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

92

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

93

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

94

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

SciTech Connect

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

95

Measuring the thermal diffusivity in a student laboratory  

E-Print Network (OSTI)

The paper describes a method for measuring the thermal diffusivity of materials having a high thermal conductivity. The apparatus is rather simple and low-cost, being therefore suitable in a laboratory for undergraduate students of engineering schools, where several set-ups are often required. A recurrence numerical approach solves the thermal field in the specimen, which is depending on the thermal diffusivity of its material. The numerical method requires the temperature data from two different positions in the specimen, measured by two thermocouples connected to a temperature logger.

Sparavigna, Amelia Carolina

2012-01-01T23:59:59.000Z

96

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

SciTech Connect

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

97

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

98

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.

99

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

NLE Websites -- All DOE Office Websites (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...

100

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

Note: This page contains sample records for the topic "thermal conductivity measurements" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
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101

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.

102

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

103

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

SciTech Connect

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

104

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

105

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

SciTech Connect

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

106

SHOCKS AND THERMAL CONDUCTION FRONTS IN RETRACTING RECONNECTED FLUX TUBES  

SciTech Connect

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

107

Measurements of the Thermal Neutron Scattering Kernel  

E-Print Network (OSTI)

Measurements of the Thermal Neutron Scattering Kernel Li (Emily) Liu, Yaron Danon, Bjorn Becker and discussions Problems and Future study Questions #12;3 M. Mattes and J. Keinert, Thermal Neutron Scattering experimental data used was from 1973-1974! M. Mattes and J. Keinert, Thermal Neutron Scattering Data

Danon, Yaron

108

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

109

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

110

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

111

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.

112

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

SciTech Connect

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

113

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-

114

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

115

Thermal diffusivity measurement system applied to polymers  

Science Journals Connector (OSTI)

In the search for cleaner energy sources the improvement of the efficiency of the actual ones appears as a primary objective. In this way thermoelectric materials which are able to convert wasted heat into electricity are reveal as an interesting way to improve efficiency of car engines for example. Cost-effective energy harvesting from thermoelectric devices requires materials with high electrical conductivities and Seebeck coefficient but low thermal conductivity. Conductive polymers can fulfil these conditions if they are doped appropriately. One of the most promising polymers is Polyaniline. In this work the thermal conductivity of the polyaniline and mixtures of polyaniline with nanoclays has been studied using a new experimental set-up developed in the lab. The novel system is based on the steady-state method and it is used to obtain the thermal diffusivity of the polymers and the nanocomposites.

2012-01-01T23:59:59.000Z

116

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

SciTech Connect

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

117

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

118

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

119

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

120

Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction  

SciTech Connect

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Ultra-sensitive and Wide Bandwidth Thermal Measurements of Graphene at Low Temperatures  

E-Print Network (OSTI)

exhibits one of the highest thermal conductivities of all measured materials[3, 4]. However at lowUltra-sensitive and Wide Bandwidth Thermal Measurements of Graphene at Low Temperatures K.C. Fong. This paper is organized as follows. We first present the thermal model of the electron gas of graphene at low

122

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

123

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.

124

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

125

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

126

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

127

A comparison between conventional hotothermal frequency scan and the lock-in rate window method in measuring thermal diffirsivity  

E-Print Network (OSTI)

that for thick materials with long thermal transport times across the sample where low-frequency measurements to measure thermal conductivity of materials by steady-state heat flow methods and thermal diffusivity for thermal diffusivity measurements of materials, is presented. In this comparison, a completely noncontact

Mandelis, Andreas

128

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

129

Thermal Dosimetry and Temperature Measurements  

Science Journals Connector (OSTI)

...Saptem ber 15 and 16, 1978, San Diego, Calif. 2 The abbreviations used are: RF, radiofrequency; LED, light-emitting diode. gross temperature measurement errors when the probes are used to monitor tissue or phantom material in an electromag...

D. A. Christensen

1979-06-01T23:59:59.000Z

130

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

131

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

SciTech Connect

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

132

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

133

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

SciTech Connect

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

134

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

SciTech Connect

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

135

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

136

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.

137

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

138

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.

139

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

140

Temperature Dependent Thermal Conductivity of Si/SiC Amorphous Multilayer Films  

SciTech Connect

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

SciTech Connect

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

142

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

SciTech Connect

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

143

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

SciTech Connect

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

144

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

145

Serpentine Thermal Coupling Between a Stream and a Conducting Body  

SciTech Connect

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

146

Measurements of thermal properties of insulation materials by using transient plane source technique  

Science Journals Connector (OSTI)

The paper reports on the measuring technique and values of the measured thermal properties of some commonly used insulation materials produced by local manufacturers in Saudi Arabia. Among the thermal properties of insulation materials, the thermal conductivity (k) is regarded to be the most important since it affects directly the resistance to transmission of heat (R-value) that the insulation material must offer. Other thermal properties, like the specific heat capacity (c) and density (?), are also important only under transient conditions. A well-suited and accurate method for measuring the thermal conductivity and diffusivity of materials is the transient plane source (TPS) technique, which is also called the hot disk (HD). This new technique is used in the present study to measure the thermal conductivity of some insulation materials at room temperature as well as at different elevated temperature levels expected to be reached in practice when these insulations are used in air-conditioned buildings in hot climates. Besides, thermal conductivity values of the same type of insulation material are measured for samples with different densities; generally, higher density insulations are used in building roofs than in walls. The results show that the thermal conductivity increases with increasing temperature and decreases with increasing density over the temperature and density ranges considered in the present investigation.

Saleh A. Al-Ajlan

2006-01-01T23:59:59.000Z

147

Measurements of prompt radiation induced conductivity of Kapton.  

SciTech Connect

We performed measurements of the prompt radiation induced conductivity in thin samples of Kapton (polyimide) at the Little Mountain Medusa LINAC facility in Ogden, UT. Three mil samples were irradiated with a 0.5 {mu}s pulse of 20 MeV electrons, yielding dose rates of 1E9 to 1E10 rad/s. We applied variable potentials up to 2 kV across the samples and measured the prompt conduction current. Analysis rendered prompt conductivity coefficients between 6E-17 and 2E-16 mhos/m per rad/s, depending on the dose rate and the pulse width.

Preston, Eric F. (ITT Corporation, Colorado Springs, CO); Zarick, Thomas Andrew; Sheridan, Timothy J.; Hartman, E. Frederick; Stringer, Thomas Arthur (ITT Corporation, Colorado Springs, CO)

2010-10-01T23:59:59.000Z

148

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

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

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

SciTech Connect

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

157

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

158

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

159

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

160

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

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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

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

SciTech Connect

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

162

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

163

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

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

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

172

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

SciTech Connect

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

173

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

174

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

175

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

SciTech Connect

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

176

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

177

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.

178

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

179

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.

180

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Conductivity Measurements of Synthesized Heteropoly Acid Membranes for Proton Exchange Membrane Fuel Cells  

SciTech Connect

Fuel cell technology is receiving attention due to its potential to be a pollution free method of electricity production when using renewably produced hydrogen as fuel. In a Proton Exchange Membrane (PEM) fuel cell H2 and O2 react at separate electrodes, producing electricity, thermal energy, and water. A key component of the PEM fuel cell is the membrane that separates the electrodes. DuPont’s Nafion® is the most commonly used membrane in PEM fuel cells; however, fuel cell dehydration at temperatures near 100°C, resulting in poor conductivity, is a major hindrance to fuel cell performance. Recent studies incorporating heteropoly acids (HPAs) into membranes have shown an increase in conductivity and thus improvement in performance. HPAs are inorganic materials with known high proton conductivities. The primary objective of this work is to measure the conductivity of Nafion, X-Ionomer membranes, and National Renewable Energy Laboratory (NREL) Developed Membranes that are doped with different HPAs at different concentrations. Four-point conductivity measurements using a third generation BekkTech? conductivity test cell are used to determine membrane conductivity. The effect of multiple temperature and humidification levels is also examined. While the classic commercial membrane, Nafion, has a conductivity of approximately 0.10 S/cm, measurements for membranes in this study range from 0.0030 – 0.58 S/cm, depending on membrane type, structure of the HPA, and the relative humidity. In general, the X-ionomer with H6P2W21O71 HPA gave the highest conductivity and the Nafion with the 12-phosphotungstic (PW12) HPA gave the lowest. The NREL composite membranes had conductivities on the order of 0.0013 – 0.025 S/cm.

Record, K.A.; Haley, B.T.; Turner, J.

2006-01-01T23:59:59.000Z

182

temperature measurements conducted by the Gulf Coast Carbon Center  

NLE Websites -- All DOE Office Websites (Extended Search)

temperature measurements conducted by the Gulf Coast Carbon Center temperature measurements conducted by the Gulf Coast Carbon Center (GCCC) at the Bureau of Economic Geology, University of Texas at Austin. The effort will examine the instrumentation necessary to ensure safe CO 2 storage by verifying CO 2 retention in the injection zone, quantify storage capacity, and quantify near- and far-field pressure response to injection. SECARB began injecting CO 2 on July 15, 2008, at a depth of 10,300 feet for enhanced oil recovery (EOR) at the Cranfield oilfield near Natchez, Mississippi. The naturally occurring CO 2 is obtained from Jackson Dome and transported by pipeline to the injection site. SECARB plans to inject CO

183

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

SciTech Connect

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

184

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

185

Measurement and modeling thermal conductivity of baked products  

E-Print Network (OSTI)

the intercept with the y-sxis (dp) and the error term (e), and adds variables one at a time until a. stopping criterion is satisfied, 0. 1 6 Q 0. 14 8 3 0. 12 g 0. 10 O V 0. 08 0. 06 + + + +y++++ ++ ~ +est~ ~ 4. + ~ c ~ + ~ f ~f, ?, , ey ~ ~ p... FOR DEPENDENT VARIABLE K STATISTICS FOR ENTRY: STEP 1 DF 1. 80 MODEL VARIABLE TOLERANCE R* 2 F PROB&F W 0 POR 1 0. 0373 3. 0995 1 0. 2539 27. 2194 1 0. 0099 0. 8006 0. 0821 0. 0001 0. 3736 STEP 1 VARIABLE D ENTERED R SQUARE = 0. 25386619 C(P) = 2...

Islas Rubio, Alma Rosa

2012-06-07T23:59:59.000Z

186

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

187

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

188

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

189

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

190

Thermal Behavior of As-Recovered (Unneutralized) Aspigel (Pressure Measurements)  

SciTech Connect

This brief report provides unreported pressures measured in accelerating rate calorimeter experiments performed to determine the thermal sensitivity of as-recovered and unneutralized Aspigel.

Scheele, Randall D.

2010-07-02T23:59:59.000Z

191

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

SciTech Connect

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

192

Effects of contact resistance on electrical conductivity measurements of SiC-based materials  

SciTech Connect

A combination 2/4-probe method was used to measure electrical resistances across a pure, monolithic CVD-SiC disc sample with contact resistance at the SiC/metallic electrode interfaces. By comparison of the almost simultaneous 2/4-probe measurements, the specific contact resistance (Rc) and its temperature dependence were determined for two types (sputtered gold and porous nickel) electrodes from room temperature (RT) to ?973 K. The Rc-values behaved similarly for each type of metallic electrode: Rc > ?1000 ? cm2 at RT, decreasing continuously to ?1–10 ? cm2 at 973 K. The temperature dependence of the inverse Rc indicated thermally activated electrical conduction across the SiC/metallic interface with an apparent activation energy of ?0.3 eV. For the flow channel insert application in a fusion reactor blanket, contact resistance potentially could reduce the transverse electrical conductivity by about 50%.

Youngblood, Gerald E.; Thomsen, Edwin C.; Henager, Charles H.

2013-06-30T23:59:59.000Z

193

Measurement of Thermal Dependencies of PBG Fiber Properties  

SciTech Connect

Photonic crystal fibers (PCFs) represent a class of optical fibers which have a wide spectrum of applications in the telecom and sensing industries. Currently, the Advanced Accelerator Research Department at SLAC is developing photonic bandgap particle accelerators, which are photonic crystal structures with a central defect used to accelerate electrons and achieve high longitudinal electric fields. Extremely compact and less costly than the traditional accelerators, these structures can support higher accelerating gradients and will open a new era in high energy physics as well as other fields of science. Based on direct laser acceleration in dielectric materials, the so called photonic band gap accelerators will benefit from mature laser and semiconductor industries. One of the key elements to direct laser acceleration in hollow core PCFs, is maintaining thermal and structural stability. Previous simulations demonstrate that accelerating modes are sensitive to the geometry of the defect region and the variations in the effective index. Unlike the telecom modes (for which over 95% of the energy propagates in the hollow core) most of the power of these modes is located in the glass at the periphery of the central hole which has a higher thermal constant than air ({gamma}{sub SiO{sub 2}} = 1.19 x 10{sup -6} 1/K, {gamma}{sub air} = -9 x 10{sup -7} 1/K with {gamma} = dn/dT). To fully control laser driven acceleration, we need to evaluate the thermal and structural consequences of such modes on the PCFs. We are conducting series of interferometric tests to quantify the dependencies of the HC-633-02 (NKT Photonics) propagation constant (k{sub z}) on temperature, vibration amplitude, stress and electric field strength. In this paper we will present the theoretical principles characterizing the thermal behavior of a PCF, the measurements realized for the fundamental telecom mode (TE{sub 00}), and the experimental demonstration of TM-like mode propagation in the HC-633-02 fiber.

Laouar, Rachik

2011-07-06T23:59:59.000Z

194

A simplified model for thermal-wave cavity self-consistent measurement of thermal diffusivity  

SciTech Connect

A simplified theoretical model was developed for the thermal-wave cavity (TWC) technique in this study. This model takes thermal radiation into account and can be employed for absolute measurements of the thermal diffusivity of gas and liquid samples without any knowledge of geometrical and thermal parameters of the components of the TWC. Using this model and cavity-length scans, thermal diffusivities of air and distilled water were accurately and precisely measured as (2.191 ± 0.004) × 10{sup ?5} and (1.427 ± 0.009) × 10{sup ?7} m{sup 2}?s{sup ?1}, respectively, in very good agreement with accepted literature values.

Shen, Jun, E-mail: jun.shen@nrc-cnrc.gc.ca; Zhou, Jianqin; Gu, Caikang [Energy, Mining and Environment Portfolio, National Research Council Canada, 4250 East Mall, Vancouver, British Columbia V6T 1W5 (Canada)] [Energy, Mining and Environment Portfolio, National Research Council Canada, 4250 East Mall, Vancouver, British Columbia V6T 1W5 (Canada); Neill, Stuart [Energy, Mining and Environment Portfolio, National Research Council Canada, 1200 Montreal Road, Building M-9, Ottawa, Ontario K1A 0R6 (Canada)] [Energy, Mining and Environment Portfolio, National Research Council Canada, 1200 Montreal Road, Building M-9, Ottawa, Ontario K1A 0R6 (Canada); Michaelian, Kirk H.; Fairbridge, Craig [CanmetENERGY, Natural Resources Canada, One Oil Drive Patch, Devon, Alberta T9G 1A8 (Canada)] [CanmetENERGY, Natural Resources Canada, One Oil Drive Patch, Devon, Alberta T9G 1A8 (Canada); Astrath, Nelson G. C.; Baesso, Mauro L. [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, Maringá, Paraná 87020-900 (Brazil)] [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, Maringá, Paraná 87020-900 (Brazil)

2013-12-15T23:59:59.000Z

195

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

SciTech Connect

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

196

Camera-based reflectivity measurement for solar thermal applications  

E-Print Network (OSTI)

Tubular receivers for solar thermal power plants, specifically tower plants, are in common use, in plantsCamera-based reflectivity measurement for solar thermal applications John D. Pye1 , Clifford K. Ho2 of the solar-weighted reflectivity of the receiver component in CSP systems. Such reflectivity measurement

197

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

198

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

199

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

200

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

202

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.

203

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

204

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

205

Front surface thermal property measurements of air plasma spray coatings  

SciTech Connect

A front-surface measurement for determining the thermal properties of thermal barrier coatings has been applied to air plasma spray coatings. The measurement is used to determine all independent thermal properties of the coating simultaneously. Furthermore, with minimal requirements placed on the sample and zero sample preparation, measurements can be made under previously impossible conditions, such as on serviceable engine parts. Previous application of this technique was limited to relatively thin coatings, where a one-dimensional heat transfer model is applied. In this paper, the influence of heat spreading on the measurement of thicker coatings is investigated with the development of a two-dimensional heat transfer model.

Bennett, Ted; Kakuda, Tyler [University of California, Santa Barbara, California 93106-5070 (United States); Kulkarni, Anand [Siemens Energy, Orlando, Florida 32826-2399 (United States)

2009-04-15T23:59:59.000Z

206

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

SciTech Connect

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

207

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

208

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

209

MEASUREMENT OF CONDUCTING ION MOBILITY AND CONCENTRATIONIN ION-CONTAINING POLYMERS.  

E-Print Network (OSTI)

??In this study, we focus on how to measure conducting ion mobility and conducting ion number density in ion-containing polymers. From a fundamental side, we… (more)

Choi, U Hyeok

2009-01-01T23:59:59.000Z

210

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

SciTech Connect

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

211

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

212

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

213

Direct Measurement of EGR Cooler Deposit Thermal Properties for Improved Understanding of Cooler Fouling  

SciTech Connect

Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with NOX emissions standards. This paper reports results of a study of fundamental aspects of EGR cooler fouling. An apparatus and procedure were developed to allow surrogate EGR cooler tubes to be exposed to diesel engine exhaust under controlled conditions. The resulting fouled tubes were removed and analyzed. Volatile and non-volatile deposit mass was measured for each tube. Thermal diffusivity of the deposited soot cake was measured by milling a window into the tube and using the Xenon flash lamp method. The heat capacity of the deposit was measured at temperatures up to 430 C and was slightly higher than graphite, presumably due to the presence of hydrocarbons. These measurements were combined to allow calculation of the deposit thermal conductivity, which was determined to be 0.041 W/mK, only ~1.5 times that of air and much lower than the 304 stainless steel tube (14.7 W/mK). The main determinant of the deposit thermal conductivity is density, which was measured to be just 2% that of the density of the primary soot particles (or 98% porous). The deposit layer thermal resistance was calculated and compared with estimates of the thermal resistance calculated from gas temperature data during the experiment. The deposit properties were also used to further analyze the temperature data collected during the experiment.

Wang, Hsin [ORNL] [ORNL; Sluder, Scott [ORNL] [ORNL; Storey, John Morse [ORNL] [ORNL

2009-01-01T23:59:59.000Z

214

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

215

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

SciTech Connect

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

216

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

SciTech Connect

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

217

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

DOE Data Explorer (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

218

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

219

Thermal Transport Measurement of Silicon-Germanium Nanowires  

E-Print Network (OSTI)

to the enhanced boundary scattering. Among the nanoscale semiconductor materials, Silicon-Germanium(SiGe) alloy nanowire is a promising candidate for thermoelectric materials The thermal conductivities of SiGe core-shell nanowires with core diameters of 96nm, 129...

Gwak, Yunki

2010-10-12T23:59:59.000Z

220

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

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

222

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

SciTech Connect

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

223

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

224

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

225

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

226

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

227

Temperature measurements using multicolor pyrometry in thermal radiation heating environments  

SciTech Connect

Temperature measurements are important for thermal-structural experiments in the thermal radiation heating environments such as used for thermal-structural stress analyses. This paper describes the use of multicolor pyrometry for the measurements of diffuse surfaces in thermal radiation environments that eliminates the effects of background radiation reflections and unknown emissivities based on a least-squares algorithm. The near-infrared multicolor pyrometer had a spectral range of 1100–2400 nm, spectrum resolution of 6 nm, maximum sampling frequency of 2 kHz, working distance of 0.6 m to infinity, temperature range of 700–1700 K. The pyrometer wavelength response, nonlinear intensity response, and spectral response were all calibrated. The temperature of a graphite sample irradiated by quartz lamps was then measured during heating and cooling using the least-squares algorithm based on the calibrated irradiation data. The experiments show that higher temperatures and longer wavelengths are more suitable for the thermal measurements in the quartz lamp radiation heating system. This analysis provides a valuable method for temperature measurements of diffuse surfaces in thermal radiation environments.

Fu, Tairan, E-mail: trfu@mail.tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China) [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Beijing 100084 (China); Liu, Jiangfan; Duan, Minghao; Zong, Anzhou [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)] [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

2014-04-15T23:59:59.000Z

228

Femtosecond-tunable measurement of electron thermalization in gold  

Science Journals Connector (OSTI)

Femtosecond electron thermalization in metals was investigated using transient thermomodulation transmissivity and reflectivity. Studies were performed using a tunable multiple-wavelength femtosecond pump-probe technique in optically thin gold films in the low perturbation limit. An IR pump beam is used to heat the electron distribution and changes in electron temperature are measured with a visible probe beam at the d band to Fermi-surface transition. We show that the subpicosecond optical response of gold is dominated by delayed thermalization of the electron gas. This effect is particularly important far off the spectral peak of the reflectivity or transmissivity changes, permitting a direct and sensitive access to the internal thermalization of the electron gas. Using a simple rate-equation model, line-shape analysis of the transient reflectivity and transmissivity indicates a thermalization time of the order of 500 fs. At energies close to the Fermi surface, longer thermalization times ?1–2 ps are observed. These results are in agreement with a more sophisticated model based on calculations of the electron-thermalization dynamics by numerical solutions of the Boltzmann equation. This model quantitatively describes the measured transient optical response during the full thermalization time of electron gas, of the order of 1.5 ps, and gives new insight into electron thermalization in metals.

C.-K. Sun; F. Vallée; L. H. Acioli; E. P. Ippen; J. G. Fujimoto

1994-11-15T23:59:59.000Z

229

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

230

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.

231

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

SciTech Connect

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

232

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

233

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

234

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

SciTech Connect

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

235

Microstructure and thermal conductivity of surfactant-free NiO nanostructures  

SciTech Connect

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

236

Microsegregation effects on the thermal conductivity of silicon-germanium alloys  

SciTech Connect

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

237

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

238

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

SciTech Connect

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

239

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.

240

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.

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

242

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

243

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

244

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

SciTech Connect

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

245

Determination of thermal accommodation coefficients from heat transfer measurements between parallel plates.  

SciTech Connect

Thermal accommodation coefficients have been derived for a variety of gas-surface combinations using an experimental apparatus developed to measure the pressure dependence of the conductive heat flux between parallel plates at unequal temperature separated by a gas-filled gap. The heat flux is inferred from temperature-difference measurements across the plates in a configuration where the plate temperatures are set with two carefully controlled thermal baths. Temperature-controlled shrouds provide for environmental isolation of the opposing test plates. Since the measured temperature differences in these experiments are very small (typically 0.3 C or less over the entire pressure range), high-precision thermistors are used to acquire the requisite temperature data. High-precision components have also been utilized on the other control and measurement subsystems in this apparatus, including system pressure, gas flow rate, plate alignment, and plate positions. The apparatus also includes the capability for in situ plasma cleaning of the installed test plates. Measured heat-flux results are used in a formula based on Direct Simulation Monte Carlo (DSMC) code calculations to determine the thermal accommodation coefficients. Thermal accommodation coefficients have been determined for three different gases (argon, nitrogen, helium) in contact with various surfaces. Materials include metals and alloys such as aluminum, gold, platinum, and 304 stainless steel. A number of materials important to fabrication of Micro Electro Mechanical Systems (MEMS) devices have also been examined. For most surfaces, coefficient values are near 0.95, 0.85, and 0.45 for argon, nitrogen, and helium, respectively. Only slight differences in accommodation as a function of surface roughness have been seen. Surface contamination appears to have a more significant effect: argon plasma treatment has been observed to reduce thermal accommodation by as much as 0.10 for helium. Mixtures of argon and helium have also been examined, and the results have been compared to DSMC simulations incorporating thermal-accommodation values from single-species experiments.

Gallis, Michail A.; Castaneda, Jaime N.; Rader, Daniel John; Torczynski, John Robert; Trott, Wayne Merle

2010-10-01T23:59:59.000Z

246

MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect

The Savannah River National Laboratory (SRNL) collected thermal imagery and ground truth data at two commercial power plant cooling lakes to investigate the applicability of laboratory empirical correlations between surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper [1] that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that the skewness of the temperature distribution derived from cooling lake thermal images correlates with instantaneous wind speed measured at the same location. SRNL collected thermal imagery, surface meteorology and water temperatures from helicopters and boats at the Comanche Peak and H. B. Robinson nuclear power plant cooling lakes. SRNL found that decreasing skewness correlated with increasing wind speed, as was the case for the laboratory experiments. Simple linear and orthogonal regression models both explained about 50% of the variance in the skewness - wind speed plots. A nonlinear (logistic) regression model produced a better fit to the data, apparently because the thermal convection and resulting skewness are related to wind speed in a highly nonlinear way in nearly calm and in windy conditions.

Garrett, A; Robert Kurzeja, R; Eliel Villa-Aleman, E; Cary Tuckfield, C; Malcolm Pendergast, M

2009-01-20T23:59:59.000Z

247

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

248

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.

249

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.

250

THERMAL PERFORMANCE MEASUREMENTS ON ULTIMATE HEAT SINKS - COOLING PONDS  

Office of Scientific and Technical Information (OSTI)

THERMAL PERFORMANCE MEASUREMENTS THERMAL PERFORMANCE MEASUREMENTS ON ULTIMATE HEAT SINKS - COOLING PONDS R. K. Hadlock 0 . B. Abbey Battelle Pacific Northwest Laboratories Prepared for U. S. Nuclear Regulatory Commission b + NOTICE This report was prepared as an account of work sponsored by the United States Government. Neither the United States nor the United States Nuclear Regulatory Commission, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, nor assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, pro- duct or process disclosed, nor represents that its use would not infringe privately owned rights. F Available from National Technical Information Service

251

Thermal Imaging Technique for Measuring Mixing of Fluids - Energy...  

NLE Websites -- All DOE Office Websites (Extended Search)

Solar Thermal Solar Thermal Energy Analysis Energy Analysis Building Energy Efficiency Building Energy Efficiency Find More Like This Return to Search Thermal Imaging Technique for...

252

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

253

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

SciTech Connect

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

254

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

255

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

256

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

257

The Envelope Thermal Test Unit (ETTU): Full Measurement of Wall Perform ance  

E-Print Network (OSTI)

Energy Conservation in the Built Environment, Dublin, Ireland, March 30-April THE ENVELOPE THERMAL TEST UNIT (ETTU): FIELD MEASUREMENT

Sonderegger, R.C.; Sherman, M.H.; Adams, J.W.

2008-01-01T23:59:59.000Z

258

The Envelope Thermal Test Unit (ETTU): Full Measurement of Wall Perform ance  

E-Print Network (OSTI)

Energy Conservation in the Built Environment, Dublin, Ireland, March 30-April THE ENVELOPE THERMAL TEST UNIT (ETTU): FIELD MEASUREMENT

Adams, J.W.

2010-01-01T23:59:59.000Z

259

Morphology development in nanoclay filled rubber compounds and rubber blends detected by online measured electrical conductance  

Science Journals Connector (OSTI)

The online measured electrical conductance (OMEC) during the rubber mixing process has been used as a novel method to characterize the dispersion of organoclay in rubber compounds and blends. This method was a...

Z. Ali; H. H. Le; S. Ilisch; H.-J. Radusch

2009-12-01T23:59:59.000Z

260

Proc. Fifteenth IEEE Semiconductor Thermal Measurement and Management Symposium, March 9-11, 1999, San Diego CA, IEEE # 99CH36306.  

E-Print Network (OSTI)

Proc. Fifteenth IEEE Semiconductor Thermal Measurement and Management Symposium, March 9-11, 1999, San Diego CA, IEEE # 99CH36306. 74 THERMAL MANAGEMENT USING "DRY" PHASE CHANGE MATERIALS R.A. Wirtz" PCM unit conductance D Heat sink depth htr Heat of transition H Fin height Hpcm PCM mass depth kal

Wirtz, Richard A.

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

262

Lifetime Assessment for Thermal Barrier Coatings: Tests for Measuring Mixed Mode Delamination Toughness  

E-Print Network (OSTI)

the thermally grown oxide (TGO), and a porous ceramic topcoat which serves as the thermal insulation. DetailsLifetime Assessment for Thermal Barrier Coatings: Tests for Measuring Mixed Mode Delamination Mechanisms leading to degradation of the adherence of thermal barrier coatings (TBC) used in aircraft

Hutchinson, John W.

263

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

SciTech Connect

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

264

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

265

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between tracer diffusion  

E-Print Network (OSTI)

Chemical oxygen diffusion coefficient measurement by conductivity relaxation--correlation between J. P., Grenier J. C., Loup J. P. ABSTRACT Chemical oxygen diusion coecient ¯(D)was measured the oxygen partial pressure in the surrounding atmosphere of the sample. The consequent evolution

Paris-Sud XI, Université de

266

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...

267

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

SciTech Connect

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

268

Development of a surface conductivity measurement system for ultrahigh vacuum transmission electron microscope  

SciTech Connect

The surface conductivity measurement system using a micro-four-point probe (M4PP) had been developed for the ultrahigh vacuum transmission electron microscope (UHV-TEM). Since the current distribution in the sample crystals during the current voltage measurement by the M4PP is localized within the depth of several micrometers from the surface, the system is sensitive to the surface conductivity, which is related with the surface superstructure. It was installed in the main chamber of the TEM and the surface conductivity can be measured in situ. The surface structures were observed by reflection electron microscopy and diffraction (REM-RHEED). REM-RHEED enables us to observe the surface superstructures and their structure defects such as surface atomic steps and domain boundaries of the surface superstructure. Thus the effects of the defects on the surface conductivity can be investigated. In the present paper we present the surface conductivity measurement system and its application to the Si(111)-{radical}(3)x{radical}(3)-Ag surface prepared on the Si(111) vicinal surfaces. The result clearly showed that the surface conductivity was affected by step configuration.

Minoda, H. [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Hatano, K.; Yazawa, H. [Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

2009-11-15T23:59:59.000Z

269

Measuring the Influence of Grain-Boundary Misorientation on Thermal Groove Geometry in Ceramic Polycrystals  

E-Print Network (OSTI)

Measuring the Influence of Grain-Boundary Misorientation on Thermal Groove Geometry in Ceramic. The width and depth of the thermal grooves formed by these same grain bound- aries were also measured of the grain-boundary misorientation and thermal groove ge- ometry leads to the observation that grain

Rohrer, Gregory S.

270

Solar wind electron temperature and density measurements on the Solar Orbiter with thermal noise spectroscopy  

E-Print Network (OSTI)

Solar wind electron temperature and density measurements on the Solar Orbiter with thermal noise of the plasma thermal noise analysis for the Solar Orbiter, in order to get accurate measurements of the total of their small mass and therefore large thermal speed, the solar wind electrons are expected to play a major role

California at Berkeley, University of

271

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

272

In-Situ Thermal Conductivity Testing Using a Portable Heat Flow Meter  

E-Print Network (OSTI)

A method has been developed for measuring heat losses from insulated systems in the field. While the measurements are not as precise as those made under laboratory conditions, they are more indicative of actual in service conditions. Extensive field...

Harr, K. S.; Hutto, F. B., Jr.

1979-01-01T23:59:59.000Z

273

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

274

IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL. 52, NO. 3, JUNE 2003 839 Comparison of IC Conducted Emission  

E-Print Network (OSTI)

of IC Conducted Emission Measurement Methods Franco Fiori, Member, IEEE, and Francesco Musolino, Member, IEEE Abstract--This paper deals with the electromagnetic emissions of integrated circuits. In particular, four measurement techniques to evaluate integrated circuit conducted emissions are described

275

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

276

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

277

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

278

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

279

Note: Electrical resolution during conductive atomic force microscopy measurements under different environmental conditions and contact forces  

SciTech Connect

Conductive atomic force microscopy experiments on gate dielectrics in air, nitrogen, and UHV have been compared to evaluate the impact of the environment on topography and electrical measurements. In current images, an increase of the lateral resolution and a reduction of the conductivity were observed in N{sub 2} and, especially, in UHV (where current depends also on the contact force). Both effects were related to the reduction/elimination of the water layer between the tip and the sample in N{sub 2}/UHV. Therefore, since current measurements are very sensitive to environmental conditions, these factors must be taken into consideration when comparisons between several experiments are performed.

Lanza, M.; Porti, M.; Nafria, M.; Aymerich, X. [Dept. Enginyeria Electronica, Universitat Autonoma de Barcelona, Edifici Q, 08193 Bellaterra (Spain); Whittaker, E.; Hamilton, B. [University of Manchester, Sackville Street, Manchester M60 JQD (United Kingdom)

2010-10-15T23:59:59.000Z

280

Four-point probe measurements of a direct current potential drop on layered conductive cylinders  

Science Journals Connector (OSTI)

We have determined the steady state electric field due to direct current flowing via point contacts at the cylindrical surface of a uniformly layered conductive rod of finite length. The solution allows one to use four-point probe potential drop measurements to estimate the conductivity or thickness of the layer assuming that the other parameters are known. The electrical potential in the rod has a zero radial derivative at its surface except at the injection and extractions points. This means that the required solution can be expressed in terms of a Green's function satisfying a Neumann boundary condition. Four-point measurements have been made to demonstrate the validity of theoretical results.

Yi Lu; John R Bowler

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

282

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

283

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

Science Journals Connector (OSTI)

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

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

2003-02-01T23:59:59.000Z

284

Optical approach to thermopower and conductivity measurements in thin-film semiconductors  

SciTech Connect

An optical beam deflection technique is applied to measure the Joule and Peltier heat generated by electric currents through thin-film semiconductors. The method yields a spatially resolved conductivity profile and allows the determination of Peltier coefficients. Results obtained on doped hydrogenated amorphous silicon films are presented.

Dersch, H.; Amer, N.M.

1984-08-01T23:59:59.000Z

285

Webster 1 Proposal: Measurement of the pressure dependence of Graphene conductivity  

E-Print Network (OSTI)

Webster 1 Proposal: Measurement of the pressure dependence of Graphene conductivity Purpose called graphene [1]. Graphene is the name given to a few layers of the more commonly known material graphite. In addition to being the first two-dimensional crystal of its kind, graphene has also shown

Minnesota, University of

286

Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis  

E-Print Network (OSTI)

Soil bulk density affects water storage, water and nutrient movement, and plant root activity in the soil profile. Its measurement is difficult in field conditions. Vibration-induced conductivity fluctuation was investigated to quantify soil bulk density with possible field applications in the future. The AC electrical conductivity of soil was measured using a pair of blade-like electrodes while exposing the soil to periodic vibration. The blades were positioned longitudinally and transversally to the direction of the induced vibration to enable the calculation of a normalized index. The normalized index was expected to provide data independent from the vibration strength and to reduce the effect of soil salinity and water content. The experiment was conducted on natural and salinized fine sand at two moisture conditions and four bulk densities. The blade-shaped electrodes improved electrode-soil contact compared to cylindrical electrodes, and thereby, reduced measurement noise. Simulations on a simplified resistor lattice indicate that the transversal effect increases as soil bulk density decreases. Measurement of dry sand showed a negative correlation between the normalized conductivity fluctuation and soil bulk density for both longitudinal and transversal settings. The decrease in the transversal signal was smaller than expected. The wet natural and salinized soils performed very similarly as hypothesized, but their normalized VICOF response was not significant to bulk density changes.

Andrea Sz. Kishne; Cristine L. S. Morgan; Hung-Chih Chang; Laszlo B. Kish

2007-05-03T23:59:59.000Z

287

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

288

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

289

ThermalPhysicsLaboratory,VanderbiltUniversity Thermal Measurement of harsh environments using  

E-Print Network (OSTI)

PhysicsLaboratory,VanderbiltUniversity Problem/Tests Cook-off Live test on MK45 Mod 4 (NSWC) ) 3/11 #12;Thermal

Walker, D. Greg

290

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

SciTech Connect

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

291

Effect of electrode configuration and electronic conductivity on current density distribution measurements in PEM fuel cells  

E-Print Network (OSTI)

. BACKGROUND In this section available literature on attempts to obtain such local current density distribution data is reviewed briefly. Cleghorn et. al. [19] conducted some pioneering current density distribution measurements on typical lab scale PEM fuel... were studied. The authors employed a combination of two load units and a specially designed patch board that acted as a multiplexer to control the voltage at the various segments. Stumper et. al. [20] analyzed three methods for current density...

Natarajan, Dilip; Nguyen, Trung Van

2004-09-03T23:59:59.000Z

292

Measurement of Conduction-Electron-Spin Relaxation in Sodium, 14-20 K  

Science Journals Connector (OSTI)

Conduction-electron-spin relaxation in sodium has been measured in the liquid-hydrogen-temperature range 14-20 K. We believe we have successfully separated the contributions to the measured relaxation rate from the impurity, surface, and electron-phonon (intrinsic) mechanisms by working with samples of controlled geometry at low rf frequency (10 MHz). The temperature dependence of the intrinsic relaxation time agrees reasonably well with the Debye-model calculations of Yafet. In our samples the probability of relaxation per surface collision for an electron spin is on the order of 10-3.

S. -K. Wang and R. T. Schumacher

1973-11-01T23:59:59.000Z

293

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

E-Print Network (OSTI)

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

Hong, Soon Hyung

294

Results of actinometric measurements at location of LSF with thermal capacity of 1000 kW  

Science Journals Connector (OSTI)

The paper considers the methods of measuring solar radiation and analyzes the long-term data obtained by actinometric measurements of solar radiation at the location of the LSF with a thermal capacity of 1000 kW ...

A. A. Abdurakhmanov; Yu. B. Sobirov; M. S. Paizullakhonov…

2012-07-01T23:59:59.000Z

295

Advancing reactive tracer methods for measuring thermal evolution...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

et al. (2003) - Use simplified geometry of hypothetical fracture system - Develop in MATLAB, to allow distribution to industry via the MATLAB compiler * Conducted 2-D finite...

296

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

SciTech Connect

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

297

Contactless measurement of nonlinear conductivity in the radio-frequency range  

E-Print Network (OSTI)

We have developed a system for contactless measurement of nonlinear conductivity in the radio-frequency band, and over a wide temperature range. A non-resonant circuit is used to electrically excite the sample, and the induced signal is detected by a resonant circuit whose natural frequency matches higher harmonics of the excitation. A simple modification of the probe allows non-resonant detection suitable for stronger signals. Two measurement procedures are proposed that allow significant excitation power variation, up to 150 W. The apparatus has been validated trough the measurement of the nonlinear response at the superconducting transition of a high-Tc superconductor, and the nematic transition of an iron pnictide.

Došli?, Marija; Požek, Miroslav

2014-01-01T23:59:59.000Z

298

Design of A Conduction-cooled 4T Superconducting Racetrack for Multi-field Coupling Measurement System  

E-Print Network (OSTI)

A conduction-cooled superconducting magnet producing a transverse field of 4 Tesla has been designed for the new generation multi-field coupling measurement system, which was used to study the mechanical behavior of superconducting samples at cryogenic temperature and intense magnetic fields. Considering experimental costs and coordinating with system of strain measurements by contactless signals (nonlinear CCD optics system), the racetrack type for the coil winding was chosen in our design, and a compact cryostat with a two-stage GM cryocooler was designed and manufactured for the superconducting magnet. The magnet was composed of a pair of flat racetrack coils wound by NbTi/Cu superconducting composite wires, a copper and stainless steel combinational form and two Bi2Sr2CaCu2Oy superconducting current leads. All the coils were connected in series and can be powered with a single power supply. The maximum central magnetic field is 4 T. In order to support the high stress and uniform thermal distribution in t...

Chen, Yuquan; Wu, Wei; Guan, Mingzhi; Wu, Beimin; Mei, Enming; Xin, Canjie

2015-01-01T23:59:59.000Z

299

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

300

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

E-Print Network (OSTI)

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

Muraya, Norman K.

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

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

SciTech Connect

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

302

Electrical conductivity and permittivity measurements near the percolation transition in a microemulsion: I. Experiment  

Science Journals Connector (OSTI)

We have made conductivity and permittivity measurements from 5–13 MHz on the microemulsion system toluene–brine–sodium-dodecyl-sulfate–butanol in the region where, by varying the brine salinity, the volume fraction of brine in the microemulsion varies from 0.1 to 0.9 as the system passes from one two-phase region to another via a three-phase region. In the two-phase region at high salinities, where the microemulsion consists of brine droplets dispersed in oil, a percolation transition, identified by a steep rise in the electrical conductivity, and a peak in the permittivity, is observed at brine volume fraction fp=0.130±0.001. This transition, although very close to the boundary between the two-phase and three-phase regions, clearly lies inside the two-phase region. The data also suggest that there is a discontinuity in the conductivity at the phase boundary, and we argue that the microemulsion undergoes a change in structure at the phase boundary.

M. T. Clarkson and S. I. Smedley

1988-03-15T23:59:59.000Z

303

Bond strength and stress measurements in thermal barrier coatings  

SciTech Connect

Thermal barrier coatings have been used extensively in aircraft gas turbines for more than 15 years to insulate combustors and turbine vanes from the hot gas stream. Plasma sprayed thermal barrier coatings (TBCs) provide metal temperature reductions as much as 300{degrees}F, with improvements in durability of two times or more being achieved. The introduction of TBCs deposited by electron beam physical vapor deposition (EB-PVD) processes in the last five years has provided a major improvement in durability and also enabled TBCs to be applied to turbine blades for improved engine performance. This program evaluates the bond strength of yttria stabilized zirconia coatings with MCrAlY and Pt-Al bond coats utilizing diffraction and fluorescence methods.

Gell, M.; Jordan, E.

1995-12-31T23:59:59.000Z

304

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements  

SciTech Connect

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

Barbera, M. [Universita degli Studi di Palermo, Dip. di Scienze Fisiche ed Astronomiche, Palermo (Italy); Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Palermo G.S. Vaiana, Palermo (Italy); Ayers, T. [Luxel Corporation, Friday Harbor (WA) (United States); Collura, A. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Palermo G.S. Vaiana, Palermo (Italy); Nasillo, G. [Universita degli Studi di Palermo, Centro Grandi Apparecchiature, Palermo (Italy); Pareschi, G.; Tagliaferri, G. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Brera, Merate (Italy)

2009-05-11T23:59:59.000Z

305

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

306

Measurements of an ARS DE204S Cryocooler's Thermal and Vibration Characteristics  

SciTech Connect

This document describes measurements that characterize an Advanced Research Systems DE204S cryocooler system. The data is relevant to the thermal performance and vibration characteristics of the cold-head. The thermal measurements include heat load mapping of the 1st and 2nd stage, and temperature fluctuation measurement of the 2nd stage heat station. A comparison of fluctuation measurements by four different sensors is also included to support the 2nd stage fluctuation results. Finally, optical measurement of the cyclic 2nd stage heat station deflection is described.

Haid, B

2004-08-24T23:59:59.000Z

307

Development of a nanostructure thermal property measurement platform compatible with a transmission electron microscope  

E-Print Network (OSTI)

Measurements of the electrical and thermal transport properties of one-dimensional nanostructures (e.g., nanotubes and nanowires) typically are obtained without detailed knowledge of the specimen's atomicscale structure ...

Harris, C. Thomas (Charles Thomas)

2010-01-01T23:59:59.000Z

308

The measurement of thermal conductivity of jelly from 25 to 95 C  

E-Print Network (OSTI)

in this research. 35 The Mechanism of Gel Formation A linear chain of anhydro-D-galacturonic acid units connected by a-(1- 4) linkage is the basic structure of pectic substances. The structure is shown in Figure 8. 0 0 OCH C 0 OH 0 OCH / C 0 OCH / 0... OCH I/ C ' . v 'i. OH OH OH H bH H Figure 8. Methyl galacturonate units of pectin. Some of the carboxylic acid groups are methylated and others are in the form of free acids. When these polysaccharides containing carboxylic acid groups...

Chen, Yih-Rong

1985-01-01T23:59:59.000Z

309

ESTIMATION OF IN-SITU THERMAL CONDUCTIVITIES FROM TEMPERATURE GRADIENT MEASUREMENTS  

E-Print Network (OSTI)

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

Hoang, V.T.

2010-01-01T23:59:59.000Z

310

Measuring the Thermal Conductivity of Irradiated Foam-Type Insulation Materials  

Science Journals Connector (OSTI)

The development of a flight-qualified nuclear-rocket propulsion system has progressed rapidly during the past three years. Space missions requiring this propulsion system are being evaluated and planned. The r...

E. T. Smith; R. E. Miller

1967-01-01T23:59:59.000Z

311

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

312

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

313

Experimentally measured thermal transport properties of aluminum–polytetrafluoroethylene nanocomposites with graphene and carbon nanotube additives  

Science Journals Connector (OSTI)

Reactive materials such as aluminum (Al) and polytetrafluoroethylene (Teflon) are used for energy generation applications and specifically in ordnance technologies. With the advent of nanotechnology various nano-scale additives have become incorporated into reactive material formulations with the hope of enhanced performance. An important component to the study of energy generation is an examination of energy transport through a reactant matrix. This study examines an experimental approach to quantifying thermal properties of an Al/Teflon nanocomposite reactant matrix that has been impregnated with carbon additives. Various structures of carbon are investigated and include amorphous nanoscale carbon spheres (nano C), graphene flakes and unaligned multiwalled carbon nanotubes (CNTs). The additives were selected based on their completely different structures with the hypothesis that the structure of the additive will influence the thermal transport properties of the matrix. Results show graphene has the greatest influence on the thermophysical properties. For example, thermal conductivity of the composites containing graphene increased by 98%. Graphene similarly enhanced the thermal diffusivity and specific heat of the Al/Teflon matrix. Conversely, nano C and \\{CNTs\\} decreased the thermal conductivity and thermal diffusivity of the samples significantly.

Keerti Kappagantula; Michelle L. Pantoya

2012-01-01T23:59:59.000Z

314

Efficient finite-time measurements under thermal regimes  

E-Print Network (OSTI)

Contrary to conventional quantum mechanics, which treats measurement as instantaneous, here we explore a model for finite-time measurement. The main two-level system interacts with the measurement apparatus in a Markovian way described by the Lindblad equation, and with an environment, which does not include the measuring apparatus. To analyse the environmental effects on the final density operator, we use the Redfield approach, allowing us to consider a non-Markovian noise. In the present hybrid theory, to trace out the environmental degrees of freedom, we use a previously-developed analytic method based on superoperator algebra and Nakajima-Zwanzig superoperators. Here, we analyse two types of system-environment interaction, phase and amplitude damping, which allows us to conclude that, in general, a finite-time quantum measurement performed during a certain period is more efficient than an instantaneous measurement performed at the end of it, because the rate of change of the populations is attenuated by the system-measurement apparatus interaction.

Carlos Alexandre Brasil; Leonardo Andreta de Castro; Reginaldo de Jesus Napolitano

2014-07-11T23:59:59.000Z

315

The performance check between whole building thermal performance criteria and exterior wall measured clear wall R-value, thermal bridging, thermal mass, and airtightness  

SciTech Connect

At the last IEA Annex 32 meeting it was proposed that the annex develop the links between level 1 (the whole building performance) and level 2 (the envelope system). This paper provides a case study of just that type of connection. An exterior wall mockup is hot box tested and modeled in the laboratory. Measurements of the steady state and dynamic behavior of this mockup are used as the basis to define the thermal bridging, thermal mass benefit and air tightness of the whole wall system. These level two performance characteristics are related to the whole building performance. They can be analyzed by a finite difference modeling of the wall assembly. An equivalent wall theory is used to convert three dimensional heat flow to one dimensional terms that capture thermal mass effects, which in turn are used in a common whole building simulation model. This paper illustrates a performance check between the thermal performance of a Massive ICF (Insulating Concrete Form) wall system mocked up (level 2) and Whole Building Performance criteria (level 1) such as total space heating and cooling loads (thermal comfort).

Kosny, J.; Christian, J.E.; Desjarlais, A.O. [Oak Ridge National Lab., TN (United States). Buildings Technology Center; Kossecka, E. [Polish Academy of Sciences (Poland); Berrenberg, L. [American Polysteel Forms (United States)

1998-06-01T23:59:59.000Z

316

Transient Non-linear Thermal FEM Simulation of Smart Power Switches and Verification by Measurements  

E-Print Network (OSTI)

Thermal FEM (Finite Element Method) simulations can be used to predict the thermal behavior of power semiconductors in application. Most power semiconductors are made of silicon. Silicon thermal material properties are significantly temperature dependent. In this paper, validity of a common non-linear silicon material model is verified by transient non-linear thermal FEM simulations of Smart Power Switches and measurements. For verification, over-temperature protection behavior of Smart Power Switches is employed. This protection turns off the switch at a pre-defined temperature which is used as a temperature reference in the investigation. Power dissipation generated during a thermal overload event of two Smart Power devices is measured and used as an input stimulus to transient thermal FEM simulations. The duration time of the event together with the temperature reference is confronted with simulation results and thus the validity of the silicon model is proved. In addition, the impact of non-linear thermal properties of silicon on the thermal impedance of power semiconductors is shown.

V. Kosel; R. Sleik; M. Glavanovics

2008-01-07T23:59:59.000Z

317

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

318

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

SciTech Connect

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

319

A Measurement Method of Actual Thermal Performance of Detached Houses  

E-Print Network (OSTI)

of residential houses based on field measurement (In Japanese), AIJ Report on Environmental engineering Vol.3, 1981 2) Martin Sandberg, J?rgen Eriksson: Commissioning of residential buildings in Sweden, IEA ECBCS Annex40 meetings held in Quebec, 2001/9, Doc...

Iwamae, A.; Nagai, H.; Miura, H.

2004-01-01T23:59:59.000Z

320

Measurement on the thermal neutron capture cross section of w-180  

E-Print Network (OSTI)

We have measured the thermal neutron capture cross section for w-180 nucleus. There is only one previous data on this cross section with a value of 30 $^{+300%}_{-100%}$ barn. To consider w-181 as a low energy neutrino source, the thermal neutron capture cross section should be measured more precisely to estimate the production rate of w-181 inside a nuclear reactor. We measured the cross section of w-180 with a natural tungsten foil and obtained a new value of 21.9 $\\pm$ 2.5 barn

W. G. Kang; Y. D. Kim; J. I. Lee; I. S. Hahn; A. R. Kim; H. J. Kim

2007-04-24T23:59:59.000Z

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Vision-based Cutaneous Sensor to Measure Both Tactile and Thermal Information for Telexistence  

E-Print Network (OSTI)

-shaped GelForce and a thermo-sensitive paint. The finger- shaped GelForce enables us to measure tactile inside the sensor body. The thermo- sensitive paint is employed to measure thermal information System]: User Interfaces-- Haptic I/O; I.2.9 [Computing Methodologies]: Robotics--Sensors 1 INTRODUCTION

Tachi, Susumu

322

Pressure Wave Measurements from Thermal Cook-Off of an HMX Based High Explosive PBX 9501  

SciTech Connect

A better understanding of thermal cook-off is important for safe handling and storing explosive devices. A number of safety issues exist about what occurs when a cased explosive thermally cooks off. For example, violence of the events as a function of confinement are important for predictions of collateral damage. This paper demonstrates how adjacent materials can be gauged to measure the resulting pressure wave and how this wave propagates in this adjacent material. The output pulse from the thermal cook-off explosive containing fixture is of obvious interest for assessing many scenarios.

Garcia, F; Forbes, J W; Tarver, C M; Urtiew, P A; Greenwood, D W; Vandersall, K S

2001-05-31T23:59:59.000Z

323

Pressure wave measurements from thermal cook-off of an HMX based high explosive  

SciTech Connect

A better understanding of thermal cook-off is important for safe handling and storing explosive devices. A number of safety issues exist about what occurs when a cased explosive thermally cooks off. For example, violence of the events as a function of confinement are important for predictions of collateral damage. This paper demonstrates how adjacent materials can be gauged to measure the resulting pressure wave and how this wave propagates in this adjacent material. The output pulse from the thermal cook-off explosive containing fixture is of obvious interest for assessing many scenarios.

Forbes, J W; Tarver, C M; Urtiew, P A; Garcia, F; Greenwood, D W; Vandersall, K S

2000-10-10T23:59:59.000Z

324

Pressure Wave Measurements from Thermal Cook-off of an HMX Based Explosive  

SciTech Connect

A better understanding of thermal cook-off is important for safe handling and storing explosive devices. A number of safety issues exist about what occurs when a cased explosive thermally cooks off. For example, violence of the events as a function of confinement are important for predictions of collateral damage. This paper demonstrates how adjacent materials can be gauged to measure the resulting pressure wave and how this wave propagates in this adjacent material. The output pulse from the thermal cook-off explosive containing fixture is of obvious interest for assessing many scenarios.

Forbes, J W; Tarver, C M; Urtiew, P A; Garcia, F; Greenwood, D W; Vandersall, K S

2001-05-09T23:59:59.000Z

325

Proposed experiment to measure {gamma}-rays from the thermal neutron capture of gadolinium  

SciTech Connect

Gadolinium-157 ({sup 157}Gd) has the largest thermal neutron capture cross section among any stable nuclei. The thermal neutron capture yields {gamma}-ray cascade with total energy of about 8 MeV. Because of these characteristics, Gd is applied for the recent neutrino detectors. Here, we propose an experiment to measure the multiplicity and the angular correlation of {gamma}-rays from the Gd neutron capture. With these information, we expect the improved identification of the Gd neutron capture.

Yano, Takatomi; Ou, I.; Izumi, T.; Yamaguchi, R.; Mori, T.; Sakuda, M. [Department of Physics, Okayama University, Okayama, 700-8530 (Japan)

2012-11-12T23:59:59.000Z

326

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.

327

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

328

Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2-  

Open Energy Info (EERE)

Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- and Water-Based Geothermal Reservoirs Geothermal Lab Call Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- and Water-Based Geothermal Reservoirs Project Type / Topic 1 Laboratory Call for Submission of Applications for Research, Development and Analysis of Geothermal Technologies Project Type / Topic 2 Tracers and Tracer Interpretation Project Description The concepts and theory behind the use of heat-sensitive tracers to study the thermal evolution of geothermal reservoirs was developed in the late 1980's under the Hot Dry Rock Project. Those studies described-conceptually and mathematically-the application of reactive tracers to tracking thermal fronts and to reservoir sizing. Later mathematical treatments focused on application of a single reactive tracer test to recover the temperature profile of a single streamtube. Previous tracer work has mainly focused on identifying conservative tracers. In these studies, chemicals that degraded at reservoir temperatures were discarded. Benzoic acids and dicarboxylic acids, which were found by Adams to degrade, may be useful as reactive tracers. Organic esters and amide tracers that undergo hydrolysis have been investigated and their use as reactive tracers appears feasible over a temperature range of 100ºC to 275ºC. However their reaction rates are pH dependent and sorption reactions have not been evaluated. While reactive tracer parameters have been measured in the lab, reactive tracers have not been extensively tested in the field. Thus, while reactive tracers appear to be a promising means of monitoring the thermal evolution of a geothermal reservoir, the concept has yet to be tested at the scale necessary for successful implementation, and tools for analyzing results of such tracer tests under the non-ideal conditions of an actual geothermal system have yet to be developed.

329

Fusion product measurements of the local ion thermal diffusivity in the PLT tokamak  

SciTech Connect

Measurement of the gradient of the d-d fusion rate profile in an ohmic PLT plasma is used to deduce the gradient of the ion temperature and, thus, the local ion thermal diffusivity through an energy balance analysis. The inferred ion diffusivity is consistent with neoclassical theory.

Heidbrink, W.W.; Lovberg, J.; Strachan, J.D.; Bell, R.E.

1986-03-01T23:59:59.000Z

330

Solar wind electron density and temperature over solar cycle 23: Thermal noise measurements on Wind  

E-Print Network (OSTI)

Solar wind electron density and temperature over solar cycle 23: Thermal noise measurements on Wind; received in revised form 6 April 2005; accepted 25 April 2005 Abstract We present the solar wind plasma parameters obtained from the Wind spacecraft during more than nine years, encompassing almost the whole solar

California at Berkeley, University of

331

Contact-independent measurement of electrical Conductance of a Thin Film with a Nanoscale Sensor  

E-Print Network (OSTI)

Contact effects are a common impediment to electrical measurements throughout the fields of nanoelectronics, organic electronics, and the emerging field of graphene electronics. We demonstrate a novel method of measuring ...

Mentzel, Tamar

332

Laboratory-Measured and Property-Transfer Modeled Saturated Hydraulic Conductivity of Snake River Plain  

E-Print Network (OSTI)

Plain Aquifer Sediments at the Idaho National Laboratory, Idaho Scientific Investigations Report 2008, Idaho: U.S. Geological Survey Scientific-Investigations Report 2008­5169, 14 p. #12;iii Contents Conductivity of Snake River Plain Aquifer Sediments at the Idaho National Laboratory, Idaho By Kim S. Perkins

333

Thermal-Equilibrium Properties of Vacancies in Metals through Current-Noise Measurements  

Science Journals Connector (OSTI)

We report a new method of measuring thermal-equilibrium properties of vacancies in metals through current-noise measurements. Aluminum noise spectra taken at 435 and 475°C directly yield vacancy lifetimes ?0=4.7×10-3 and 2.8×10-3 sec, respectively, corresponding to a migration energy Em=0.6 eV, and permit estimation of a unit vacancy resistivity ??v=1.9×10-8 ?m/at.% from the measured product (??v)2?v, ?v being the vacancy concentration taken from literature data.

M. Celasco; F. Fiorillo; P. Mazzetti

1976-01-05T23:59:59.000Z

334

Verification of a XeCl* laser model by measurement of the plasma conductivity  

Science Journals Connector (OSTI)

Measurements of current, voltage, and laser emission of an X-ray preionized selfsustained XeCl* laser discharge using Ne:Xe:HCl gas mixtures are compared with predictions of spatially homogeneous model calculatio...

G. Stielow; Th. Hammer; W. Bötticher

1988-12-01T23:59:59.000Z

335

Orientational Defects in Ice Ih: An Interpretation of Electrical Conductivity Measurements  

Science Journals Connector (OSTI)

We present a first-principles study of the structure and energetics of Bjerrum defects in ice Ih and compare the results to experimental electrical conductivity data. While the DFT result for the activation energy is in good agreement with experiment, we find that its two components have quite different values. Aside from providing new insight into the fundamental parameters of the microscopic electrical theory of ice, our results suggest the activity of traps in doped ice in the temperature regime typically assumed to be controlled by the free migration of L defects.

Maurice de Koning; Alex Antonelli; Antonio J. R. da Silva; A. Fazzio

2006-02-21T23:59:59.000Z

336

Measurements of static electrical conductivity of a dense plasma in a magnetic field  

Science Journals Connector (OSTI)

New experimental setup for generation of a non-ideal plasma, placed in a magnetic field of up to 25 T, is presented. The plasma generation technique is based on gas compression and heating behind the front of a shock wave with the use of an explosively driven linear generator. The magnetic field is produced by a discharge of a capacitor through a solenoid reeled on the generator channel. DC electrical conductivity of the plasma is determined by two and four contact techniques. Possibilities of magnetized dense plasma generation are discussed.

N S Shilkin; D S Yuriev; S V Dudin; V B Mintsev; V E Fortov

2006-01-01T23:59:59.000Z

337

Thermal history sensors for non-destructive temperature measurements in harsh environments  

Science Journals Connector (OSTI)

The operating temperature is a critical physical parameter in many engineering applications however can be very challenging to measure in certain environments particularly when access is limited or on rotating components. A new quantitative non-destructive temperature measurement technique has been proposed which relies on thermally induced permanent changes in ceramic phosphors. This technique has several distinct advantages over current methods for many different applications. The robust ceramic material stores the temperature information allowing long term thermal exposures in harsh environment to be measured at a convenient time. Additionally rare earth dopants make the ceramic phosphorescent so that the temperature information can be interpreted by automated interrogation of the phosphorescent light. This technique has been demonstrated by application of YAG doped with dysprosium and europium as coatings through the air-plasma spray process. Either material can be used to measure temperature over a wide range namely between 300°C and 900°C. Furthermore results show that the material records the peak exposure temperature and prolonged exposure at lower temperatures would have no effect on the temperature measurement. This indicates that these materials could be used to measure peak operating temperatures in long-term testing.

2014-01-01T23:59:59.000Z

338

Thermal history sensors for non-destructive temperature measurements in harsh environments  

SciTech Connect

The operating temperature is a critical physical parameter in many engineering applications, however, can be very challenging to measure in certain environments, particularly when access is limited or on rotating components. A new quantitative non-destructive temperature measurement technique has been proposed which relies on thermally induced permanent changes in ceramic phosphors. This technique has several distinct advantages over current methods for many different applications. The robust ceramic material stores the temperature information allowing long term thermal exposures in harsh environment to be measured at a convenient time. Additionally, rare earth dopants make the ceramic phosphorescent so that the temperature information can be interpreted by automated interrogation of the phosphorescent light. This technique has been demonstrated by application of YAG doped with dysprosium and europium as coatings through the air-plasma spray process. Either material can be used to measure temperature over a wide range, namely between 300°C and 900°C. Furthermore, results show that the material records the peak exposure temperature and prolonged exposure at lower temperatures would have no effect on the temperature measurement. This indicates that these materials could be used to measure peak operating temperatures in long-term testing.

Pilgrim, C. C. [Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK and Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom); Heyes, A. L. [Energy Technology and Innovation Initiative, University of Leeds, Leeds, LS2 9JT (United Kingdom); Feist, J. P. [Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom)

2014-02-18T23:59:59.000Z

339

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

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

340

The measurement of absolute thermal neutron flux using liquid scintillation counting techniques  

E-Print Network (OSTI)

was computed as the square root of the sum of the squares of the individual errors . The flux at the same location in the core and at the same reactor power level was measured by the conventional technique of gold foil 34 activation. This measurement... back to 1932 when the neutron was discovered by Chadwick. With the advent of the nuclear reactor in 1942 the problem of absolute neutron flux determination became increasingly important. Since the operating power of a thermal reactor is directly...

Walker, Jack Vernon

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

The Thermal Insulation Properties for Wall Material with Various Water Contents  

Science Journals Connector (OSTI)

The thermal conductivities of wall material were measured under various water contents to investigate the effect of water content on the thermal insulation properties. The results show that water contents have adverse impact to heat insulation of wall ... Keywords: the thermal conductivity, water contents, the thermal insulation properties

Zhang Chuancheng; Lu Haijun

2010-05-01T23:59:59.000Z

342

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

343

Measurement of neutron capture on $^{48}$Ca at thermal and thermonuclear energies  

E-Print Network (OSTI)

At the Karlsruhe pulsed 3.75\\,MV Van de Graaff accelerator the thermonuclear $^{48}$Ca(n,$\\gamma$)$^{49}$Ca(8.72\\,min) cross section was measured by the fast cyclic activation technique via the 3084.5\\,keV $\\gamma$-ray line of the $^{49}$Ca-decay. Samples of CaCO$_3$ enriched in $^{48}$Ca by 77.87\\,\\% were irradiated between two gold foils which served as capture standards. The capture cross-section was measured at the neutron energies 25, 151, 176, and 218\\,keV, respectively. Additionally, the thermal capture cross-section was measured at the reactor BR1 in Mol, Belgium, via the prompt and decay $\\gamma$-ray lines using the same target material. The $^{48}$Ca(n,$\\gamma$)$^{49}$Ca cross-section in the thermonuclear and thermal energy range has been calculated using the direct-capture model combined with folding potentials. The potential strengths are adjusted to the scattering length and the binding energies of the final states in $^{49}$Ca. The small coherent elastic cross section of $^{48}$Ca+n is explained through the nuclear Ramsauer effect. Spectroscopic factors of $^{49}$Ca have been extracted from the thermal capture cross-section with better accuracy than from a recent (d,p) experiment. Within the uncertainties both results are in agreement. The non-resonant thermal and thermonuclear experimental data for this reaction can be reproduced using the direct-capture model. A possible interference with a resonant contribution is discussed. The neutron spectroscopic factors of $^{49}$Ca determined from shell-model calculations are compared with the values extracted from the experimental cross sections for $^{48}$Ca(d,p)$^{49}$Ca and $^{48}$Ca(n,$\\gamma$)$^{49}$Ca.

H. Beer; C. Coceva; P. V. Sedyshev; Yu. P. Popov; H. Herndl; R. Hofinger; P. Mohr; H. Oberhummer

1996-08-07T23:59:59.000Z

344

American National Standard ANSI/ANS-8. 6, Safety in conducting subcritical neutron---Multiplication measurement in situ  

SciTech Connect

There are many examples of expeditious and cost effective in situ measurements dating from the 1940's and 50's. These subcritical experiment, upon which the safety of operations were based, were paralleled by numerous critical experiments which provide most of the bases for computer code validations presently. As the capability to expeditiously and cost effectively perform critical experiments withers, in situ subcritical measurements may provide the information necessary to further reduce uncertainties and biases in safety margins and thus incorporate more safety and efficiency into process operations. Finally, certain site restoration activities may demand knowledge of the subcritical state before disturbing the buried material. In situ neutron multiplication measurements may offer the only practical means to this knowledge. This document discusses the standard of conducting subcritical Neutron-Multiplication measurements, in situ. 4 refs., 1 fig.

McLaughlin, T.P.

1991-01-01T23:59:59.000Z

345

New contactless method for thermal diffusivity measurements using modulated photothermal radiometry  

SciTech Connect

Modulated photothermal radiometry is a non-destructive and contactless technique for the characterization of materials. It has two major advantages: a good signal-to-noise ratio through a synchronous detection and a low dependence on the heating power and the optical properties of the sample surface. This paper presents a new method for characterizing the thermal diffusivity of a material when the phase shift between a modulated laser power signal and the thermal signal of a plate sample is known at different frequencies. The method is based on a three-dimensional analytical model which is used to determine the temperature amplitude and the phase in the laser heating of the plate. A new simple formula was developed through multi-parametric analysis to determine the thermal diffusivity of the plate with knowledge of the frequency at the minimum phase shift, the laser beam radius r{sub 0} and the sample thickness L. This method was developed to control the variation of the thermal diffusivity of nuclear components and it was first applied to determine the thermal diffusivity of different metals: 304 L stainless steel, nickel, titanium, tungsten, molybdenum, zinc, and iron. The experimental results were obtained with 5%–10% accuracy and corresponded well with the reference values. The present paper also demonstrates the limit of application of this method for plate with thickness r{sub 0}/100 ? L ? r{sub 0}/2. The technique is deemed interesting for the characterization of barely accessible components that require a contactless measurement.

Pham Tu Quoc, S., E-mail: sang.phamtuquoc@cea.fr; Cheymol, G.; Semerok, A. [French Alternative Energies and Atomic Energy Commission, Division of Nuclear Energy, DEN/DANS/DPC/SEARS/LISL, 91191 Gif/Yvette (France)] [French Alternative Energies and Atomic Energy Commission, Division of Nuclear Energy, DEN/DANS/DPC/SEARS/LISL, 91191 Gif/Yvette (France)

2014-05-15T23:59:59.000Z

346

A review of recent measurements of optical and thermal properties of. alpha. -mercuric iodide  

SciTech Connect

The knowledge of the physical properties of a crystal and their relation to the nature and content of defects are essential for both applications and fundamental reasons. Alpha-mercuric iodide ({alpha}-HgI{sub 2}) is a material which was found important applications as room temperature X-ray and gamma ray detectors. Some recent thermal and optical measurements of this material, using the samples of improved crystallinity which are now available, are reviewed below. Heretofore, these properties have received less attention than the mechanical and electrical properties, particularly at elevated temperatures. In the technology of {alpha}-HgI{sub 2} where there is a continuing motivation to obtain larger single crystals without compromising the material quality, a better knowledge of the thermal and optical properties may lead to improvements in the processes of material purification, crystal growth and device fabrication.

Burger, A.; Morgan, S.H.; Silberman, E. (Fisk Univ., Nashville, TN (United States). Dept. of Physics); Nason, D.; Cheng, A.Y. (EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations)

1991-01-01T23:59:59.000Z

347

Gamma-gamma directional correlation measurements in 84Kr following thermal neutron capture by natural krypton  

Science Journals Connector (OSTI)

Directional correlations of gamma-ray cascades in 84Kr have been measured following thermal neutron capture by a pressurised natural krypton gas target. Gamma-ray singles spectra were measured up to 5.5 MeV and the correlation data were obtained for the energy range 0.2-2.5 MeV. A decay scheme was developed on the basis of coincidence measurements. The data allow spin-parity assignments to be made to most levels lying below 3.5 MeV and multipole mixing ratios to be evaluated for the more intense transitions. The results are fitted to the SU(5) limit of the IBM-1 and to the IBM-2 and are also compared with the predictions of the dynamic deformation model which indicates that 84Kr is the only krypton isotope with a prolate equilibrium shape. A possible mixed symmetry 2+ state at 2.623 MeV is identified.

S A Hamada; W D Hamilton; F Hoyler

1987-01-01T23:59:59.000Z

348

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

SciTech Connect

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

349

A thermal method for measuring the rate of water movement in plants  

E-Print Network (OSTI)

L?BP A 8 V a L ?BPA8B8 op A THERMAL METHOD FOR MEASURING THE RATE OF WATER MOVEMENT IN PLANTS A Dissertation By Morris Elkins Bloodworth Vao Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in Partial... Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY May, 1958 TLX Major Subject: Soil Physics p ^i???pP ??^i?? ??? ??p?????? ^i? ?p^? ?? WATER MOVEMENT IN PLANTS A Dissertation By Morris Elkins Bloodworth Approved as to style...

Bloodworth, Morris Elkins

1958-01-01T23:59:59.000Z

350

MULTISCALE THERMAL-INFRARED MEASUREMENTS OF THE MAUNA LOA CALDERA, HAWAII  

SciTech Connect

Until recently, most thermal infrared measurements of natural scenes have been made at disparate scales, typically 10{sup {minus}3}-10{sup {minus}2} m (spectra) and 10{sup 2}-10{sup 3} m (satellite images), with occasional airborne images (10{sup 1} m) filling the gap. Temperature and emissivity fields are spatially heterogeneous over a similar range of scales, depending on scene composition. A common problem for the land surface, therefore, has been relating field spectral and temperature measurements to satellite data, yet in many cases this is necessary if satellite data are to be interpreted to yield meaningful information about the land surface. Recently, three new satellites with thermal imaging capability at the 10{sup 1}-10{sup 2} m scale have been launched: MTI, TERRA, and Landsat 7. MTI acquires multispectral images in the mid-infrared (3-5{micro}m) and longwave infrared (8-10{micro}m) with 20m resolution. ASTER and MODIS aboard TERRA acquire multispectral longwave images at 90m and 500-1000m, respectively, and MODIS also acquires multispectral mid-infrared images. Landsat 7 acquires broadband longwave images at 60m. As part of an experiment to validate the temperature and thermal emissivity values calculated from MTI and ASTER images, we have targeted the summit region of Mauna Loa for field characterization and near-simultaneous satellite imaging, both on daytime and nighttime overpasses, and compare the results to previously acquired 10{sup {minus}1} m airborne images, ground-level multispectral FLIR images, and the field spectra. Mauna Loa was chosen in large part because the 4x6km summit caldera, flooded with fresh basalt in 1984, appears to be spectrally homogeneous at scales between 10{sup {minus}1} and 10{sup 2} m, facilitating the comparison of sensed temperature. The validation results suggest that, with careful atmospheric compensation, it is possible to match ground measurements with measurements from space, and to use the Mauna Loa validation site for cross-comparison of thermal infrared sensors and temperature/emissivity extraction algorithms.

L. BALICK; A. GILLESPIE; ET AL

2001-03-01T23:59:59.000Z

351

Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing  

DOE Patents (OSTI)

The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10[sup [minus]5] cm[sup [minus]1] has been demonstrated using this technique. 6 figs.

Cremers, D.A.; Keller, R.A.

1985-10-01T23:59:59.000Z

352

Research options for the development of sensors to measure the thermal state of solid steel bodies.  

SciTech Connect

The purpose of the study reported here is to assist Battelle's Pcacific Northwest Laboratory (PNL) in planning a research and development program to develop temperature sensors for metal and ceramic industries. This study focuses on sensors to measure internal temperatures within bodies of hot steel. A series of literature surveys, interviews, field visits, and meetings with steel-industry organizations was conducted in seeking answers to questions posed by PNL. These questions, with responses, are summarized.

Gaspar, T.A.; Lownie, H.W. Jr.

1983-02-01T23:59:59.000Z

353

MDT Ageing Studies Results of the measurements conducted at the Gamma Irradiation Facility GIF between autumn 2001 and summer 2003  

E-Print Network (OSTI)

This note summarizes the results of MDT ageing studies conducted at the CERN Gamma Irradiation Facility GIF between autumn 2001 and summer 2003, using for the first time a series-production MDT chamber (of type BIS) and a prototype of the gas recirculation system to be installed at Atlas. The main outcome of the measurements was a very high sensitivity towards any silicone contamination of the Atlas MDTs when operated in a high rate environment. The ageing effects observed were traced to several contaminated parts in the off-chamber gas system, proving the paramount importance of an effective quality control during the gas system assembly and component selection process.

Zimmermann, S

2004-01-01T23:59:59.000Z

354

MEASUREMENTS OF ANISOTROPIC ION TEMPERATURES, NON-THERMAL VELOCITIES, AND DOPPLER SHIFTS IN A CORONAL HOLE  

SciTech Connect

We present a new diagnostic allowing one to measure the anisotropy of ion temperatures and non-thermal velocities, as well as Doppler shifts with respect to the ambient magnetic field. This method provides new results, as well as an independent test for previous measurements obtained with other techniques. Our spectral data come from observations of a low-latitude, on-disk coronal hole. A potential field source surface model was used to calculate the angle between the magnetic field lines and the line of sight for each spatial bin of the observation. A fit was performed to determine the line widths and Doppler shifts parallel and perpendicular to the magnetic field. For each line width component we derived ion temperatures T {sub i,} and T {sub i, Parallel-To} and non-thermal velocities v {sub nt,} and v {sub nt, Parallel-To }. T {sub i,} was cooler than off-limb polar coronal hole measurements, suggesting increasing collisional cooling with decreasing height. T {sub i, Parallel-To} is consistent with a uniform temperature of (1.8 {+-} 0.2) Multiplication-Sign 10{sup 6} K for each ion. Since parallel ion heating is expected to be weak, this ion temperature should reflect the proton temperature. A comparison between our results and others implies a large proton temperature gradient around 1.02 R {sub Sun }. The non-thermal velocities are thought to be proportional to the amplitudes of various waves. Our results for v {sub nt,} agree with Alfven wave amplitudes inferred from off-limb polar coronal hole line width measurements. Our v {sub nt, Parallel-To} results are consistent with slow magnetosonic wave amplitudes inferred from Fourier analysis of time-varying intensity fluctuations. Doppler shift measurements yield outflows of Almost-Equal-To 5 km s{sup -1} for ions formed over a broad temperature range. This differs from other studies that found a strong Doppler shift dependence on formation temperature.

Hahn, M.; Savin, D. W. [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)] [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)

2013-02-15T23:59:59.000Z

355

Study on the heat conduction of phase-change material microcapsules  

Science Journals Connector (OSTI)

The 3? approach was used to measure the effective thermal conductivity of phase-change material microcapsules (PCMMs) based on urea formaldehyde ... PCMMs with different densities were measured within the phase-change

Gangtao Zhao; Xiaohui Xu; Lin Qiu; Xinghua Zheng; Dawei Tang

2013-06-01T23:59:59.000Z

356

Strains in Thermally Growing Alumina Films Measured in-situ usingSynchrotron X-rays  

SciTech Connect

Strains in thermally grown oxides have been measured in-situ, as the oxides develop and evolve. Extensive data have been acquired from oxides grown in air at elevated temperatures on different model alloys that form Al{sub 2}O{sub 3}. Using synchrotron x-rays at the Advanced Photon Source (Beamline 12BM, Argonne National Laboratory), Debye-Scherrer diffraction patterns from the oxidizing specimen were recorded every 5 minutes during oxidation and subsequent cooling. The diffraction patterns were analyzed to determine strains in the oxides, as well as phase changes and the degree of texture. To study a specimen's response to stress perturbation, the oxidizing temperature was quickly cooled from 1100 to 950 C to impose a compressive thermal stress in the scale. This paper describes this new experimental approach and gives examples from oxidized {beta}-NiAl, Fe-20Cr-10Al, Fe-28Al-5Cr and H{sub 2}-annealed Fe-28Al-5Cr (all at. %) alloys to illustrate some current understanding of the development and relaxation of growth stresses in Al{sub 2}O{sub 3}.

Hou, P.Y.; Paulikas, A.P.; Veal, B.W.

2006-01-02T23:59:59.000Z

357

Resistivity measurements of halide-salt/MgO separators for thermal cells  

SciTech Connect

Resistivities of 20 compositions of halide-salt/MgO mixtures (various selections and percentages of LiF, LiCl, LiBr, KCl, KBr, CsBr, and MgO) to be used in Li-alloy/metal sulfide cells have been measured at temperatures between the melting point of a particular mixture and 500{degrees}C. The resistivities were determined with cold-pressed electrolyte-binder pellets by using a special cell and DC measuring technique. Temperature, salt composition, and MgO content were found to have a strong influence on resistivity. These factors are listed in decreasing order of the magnitude of the effect. The fabrication density (porosity) of the pellet also has some effect on resistivity. These measured resistivities provide a data base to select optimum compositions of electrolyte-binder pellets for LiSi/FeS{sub 2} thermal batteries and to calculate area-specific resistances of these components for battery modeling and optimization. 5 refs., 7 figs.

Redey, L.; McParland, M. (Argonne National Lab., IL (USA)); Guidotti, R. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01T23:59:59.000Z

358

Measurement of Reactive Hydroxyl Radical Species Inside the Biosolutions During Non-thermal Atmospheric Pressure Plasma Jet Bombardment onto the Solution  

Science Journals Connector (OSTI)

Non-thermal atmospheric pressure plasma jet could generate various kinds of radicals ... The electron temperature and ion density for this non-thermal plasma jet have been measured to be about...13 cm?3 in this e...

Yong Hee Kim; Young June Hong; Ku Youn Baik…

2014-05-01T23:59:59.000Z

359

Measurement of thermal properties of select intact and weathered granulites and their relationship to rock properties  

Science Journals Connector (OSTI)

...in hard rock: Renewable Energy, 28 , no.-14...basalt samples in Egypt: Journal of Thermal...in hard rock: Renewable Energy, 28, no. 14...basalt samples in Egypt: Journal of Thermal...parameterization on surface energy fluxes and temperatures...

D. Ramakrishnan; Rishikesh Bharti; M. Nithya; K. N. Kusuma; K. D. Singh

360

Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.  

SciTech Connect

Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS-Raman imaging. FRS has been applied to a sooting C2H4-air flame and combined with LII to assess the upper sooting limit where FRS may be utilized. The results from this sooting flame show FRS temperatures has potential for quantitative temperature imaging for soot volume fractions of order 0.1 ppm. FRS velocity measurements have been performed in a Mach 3.7 overexpanded nitrogen jet. The FRS results are in good agreement with expected velocities as predicted by inviscid analysis of the jet flowfield. We have constructed a second FRS opto-electronic system for measurements at Sandia's hypersonic wind tunnel. The details of this second FRS system are provided here. This facility is currently being used for velocity characterization of these production hypersonic facilities.

Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "thermal conductivity measurements" 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
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361

JOURNAL DE PHYSIQUE CoZZoque C8, suppZ6ment au n08, Tome 41, aoiit 1980, page C8-745 LOW TEMPERATURE THERMAL PROPERTIES OF AMORPHOUS SUPERCONDUCTING ZrCu  

E-Print Network (OSTI)

in these materials. In this paper we present measurements of the thermal conductivity and specific heat of Zrl resistivity value po is smaller thah 20 mK for all samples. The thermal conductivity k of ZrCu was measured and 1.7 K, respectively, as determined by the electrical resistivity. The thermal conductivity of a 6o

Paris-Sud XI, Université de

362

Contamination of Cluster Radio Sources in the Measurement of the Thermal Sunyaev-Zel'dovich Angular Power Spectrum  

E-Print Network (OSTI)

We present a quantitative estimate of the confusion of cluster radio halos and galaxies in the measurement of the angular power spectrum of the thermal Sunyaev-Zel'dovich (SZ) effect. To achieve the goal, we use a purely analytic approach to both radio sources and dark matter of clusters by incorporating empirical models and observational facts together with some theoretical considerations. It is shown that the correction of cluster radio halos and galaxies to the measurement of the thermal SZ angular power spectrum is no more than 20% at $l>2000$ for observing frequencies $\

Wei Zhou; Xiang-Ping Wu

2003-09-26T23:59:59.000Z

363

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

364

MONITORING POWER PLANT EFFICIENCY USING THE MICROWAVE-EXCITED THERMAL-ACOUSTIC EFFECT TO MEASURE UNBURNED CARBON  

SciTech Connect

The objective of this project is to explore microwave-excited thermal-acoustic (META) phenomena for quantitative analysis of granular and powdered materials, with the culmination of the research to be an on-line carbon-in-ash monitor for coal-fired power plants. This technique of analyzing unburned carbon in fly ash could be a less tedious and time consuming method as compared to the traditional LOI manual procedure. Phase 1 of the research focused on off-line single-frequency thermal-acoustic measurements where an off-line fly ash monitor was constructed that could operate as analytical tool to explore instrument and methodology parameters for quantifying the microwave-excited thermal-acoustic effect of carbon in fly ash, and it was determined that the off-line thermal-acoustic technique could predict the carbon content of a random collection of fly ashes with a linear correlation constant of R{sup 2} = 0.778. Much higher correlations are expected for fly ashes generated from a single boiler. Phase 2 of the research developing a methodology to generate microwave spectra of various powders, including fly ash, coal, and inorganic minerals, and to determine if these microwave spectra could be used for chemical analyses. Although different minerals produced different responses, higher resolution microwave spectra would be required to be able to distinguish among minerals. Phase 3 of the research focused on the development of an on-line fly ash monitor that could be adapted to measure either a thermal-acoustic or thermal-elastic response to due microwave excitation of fly ash. The thermal-acoustic response was successfully employed for this purpose but the thermal-elastic response was too weak to yield a useful on-line device.

Robert C. Brown; Robert J. Weber; Jeffrey J. Swetelitsch

2005-01-01T23:59:59.000Z

365

Measuring the Optical Performance of Evacuated Receivers via an Outdoor Thermal Transient Test: Preprint  

SciTech Connect

Modern parabolic trough solar collectors operated at high temperatures to provide the heat input to Rankine steam power cycles employ evacuated receiver tubes along the collector focal line. High performance is achieved via the use of a selective surface with a high absorptance for incoming short-wave solar radiation and a low emittance for outgoing long-wave infrared radiation, as well as the use of a hard vacuum to essentially eliminate convective and conductive heat losses. This paper describes a new method that determines receiver overall optical efficiency by exposing a fluid-filled, pre-cooled receiver to one sun outdoors and measuring the slope of the temperature curve at the point where the receiver temperature passes the glass envelope temperature (that is, the point at which there is no heat gain or loss from the absorber). This transient test method offers the potential advantages of simplicity, high accuracy, and the use of the actual solar spectrum.

Kutscher, C.; Burkholder, F.; Netter, J.

2011-08-01T23:59:59.000Z

366

RESEARCHANDTECHNICALNOTES Thermal contraction of Vespel SP-22 and  

E-Print Network (OSTI)

materials is becoming common in low temperature apparatus. Vespel SP-22 has a thermal conductivity nearly of thermal contraction of such construction materials is often necessary for proper design of low temperature devices. We present here data on the total thermal contraction of these two materials, measured relative

Packard, Richard E.

367

The measurement of eddy current conductivity, in view of its frequen-cy dependent penetration depth, has been suggested as a possible means to  

E-Print Network (OSTI)

of materials, including gas turbine engine components, where the resulting combination of hardening) of subsurface residual stresses in shot peened specimens. This paper addresses the apparent reduction thermally treated and tested by X-ray diffraction measurements until the residual stress and cold work fully

Nagy, Peter B.

368

Nanoscale thermal transport. II. 2003–2012  

SciTech Connect

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

369

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

370

Ambient variation-tolerant and inter components aware thermal management for mobile system on chips  

E-Print Network (OSTI)

, such as thermal conductivity and heat capacity of the package including cover, display and battery are measuredAmbient variation-tolerant and inter components aware thermal management for mobile system on chips:josephz@qti.qualcomm.com Abstract-- In this work we measure and study two key aspects of the thermal behavior of smartphones: 1

Simunic, Tajana

371

Measurement of the fluence response of the GSI neutron ball dosemeter in the energy range from thermal to 19 MeV  

Science Journals Connector (OSTI)

......the GKSS research reactor FRG-1 in Geesthacht. For the accelerator measurements...thermal neutrons was performed at the Geesthacht Neutron Facility (GeNF) laboratory...the GKSS research reactor FRG-1 in Geesthacht. For the accelerator measurements......

G. Fehrenbacher; E. Kozlova; F. Gutermuth; T. Radon; R. Schütz; R. Nolte; R. Böttger

2007-08-01T23:59:59.000Z

372

Crystallization Behavior of Virgin TR-55 Silicone Rubber Measured Using Dynamic Mechanical Thermal Analysis with Liquid Nitrogen Cooling  

SciTech Connect

Dynamic mechanical thermal analysis (DMTA) of virgin TR-55 silicone rubber specimens was conducted. Two dynamic temperature sweep tests, 25 to -100 C and 25 to -70 to 0 C (ramp rate = 1 C/min), were conducted at a frequency of 6.28 rad/s (1 Hz) using a torsion rectangular test geometry. A strain of 0.1% was used, which was near the upper limit of the linear viscoelastic region of the material based on an initial dynamic strain sweep test. Storage (G{prime}) and loss (G{double_prime}) moduli, the ratio G{double_prime}/G{prime} (tan {delta}), and the coefficient of linear thermal expansion ({alpha}) were determined as a function of temperature. Crystallization occurred between -40 and -60 C, with G{prime} increasing from {approx}6 x 10{sup 6} to {approx}4 x 10{sup 8} Pa. The value of {alpha} was fairly constant before ({approx}4 x 10{sup -4} mm/mm- C) and after ({approx}3 x 10{sup -4} mm/mm- C) the transition, and peaked during the transition ({approx}3 x 10{sup -3} mm/mm- C). Melting occurred around -30 C upon heating.

Small IV, W; Wilson, T S

2010-02-11T23:59:59.000Z

373

Advancing Reactive Tracer Methods for Measurement of Thermal Evolution in Geothermal Reservoirs: Final Report  

SciTech Connect

The injection of cold fluids into engineered geothermal system (EGS) and conventional geothermal reservoirs may be done to help extract heat from the subsurface or to maintain pressures within the reservoir (e.g., Rose et al., 2001). As these injected fluids move along fractures, they acquire heat from the rock matrix and remove it from the reservoir as they are extracted to the surface. A consequence of such injection is the migration of a cold-fluid front through the reservoir (Figure 1) that could eventually reach the production well and result in the lowering of the temperature of the produced fluids (thermal breakthrough). Efficient operation of an EGS as well as conventional geothermal systems involving cold-fluid injection requires accurate and timely information about thermal depletion of the reservoir in response to operation. In particular, accurate predictions of the time to thermal breakthrough and subsequent rate of thermal drawdown are necessary for reservoir management, design of fracture stimulation and well drilling programs, and forecasting of economic return. A potential method for estimating migration of a cold front between an injection well and a production well is through application of reactive tracer tests, using chemical whose rate of degradation is dependent on the reservoir temperature between the two wells (e.g., Robinson 1985). With repeated tests, the rate of migration of the thermal front can be determined, and the time to thermal breakthrough calculated. While the basic theory behind the concept of thermal tracers has been understood for some time, effective application of the method has yet to be demonstrated. This report describes results of a study that used several methods to investigate application of reactive tracers to monitoring the thermal evolution of a geothermal reservoir. These methods included (1) mathematical investigation of the sensitivity of known and hypothetical reactive tracers, (2) laboratory testing of novel tracers that would improve method sensitivity, (3) development of a software tool for design and interpretation of reactive tracer tests and (4) field testing of the reactive tracer temperature monitoring concept.

Mitchell A. Plummer; Carl D. Palmer; Earl D. Mattson; Laurence C. Hull; George D. Redden

2011-07-01T23:59:59.000Z

374

Thermal imaging measurement of lateral diffusivity and non-invasive material defect detection  

DOE Patents (OSTI)

A system and method for determining lateral thermal diffusivity of a material sample using a heat pulse; a sample oriented within an orthogonal coordinate system; an infrared camera; and a computer that has a digital frame grabber, and data acquisition and processing software. The mathematical model used within the data processing software is capable of determining the lateral thermal diffusivity of a sample of finite boundaries. The system and method may also be used as a nondestructive method for detecting and locating cracks within the material sample.

Sun, Jiangang (Westmont, IL); Deemer, Chris (Downers Grove, IL)

2003-01-01T23:59:59.000Z

375

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

376

American Institute of Aeronautics and Astronautics Measurements for fuel reforming for scramjet thermal management and  

E-Print Network (OSTI)

of liquid hydrocarbon halved)3 . When heated and pyrolysed, it produces lighter hydrocarbons species thermal management and combustion optimization : 2009 status of the COMPARER project. Gregory. ABRAHAM1. But even CMC materials could not withstand such large heat loads (for example, total temperature

Paris-Sud XI, Université de

377

Building design and thermal renovation measures proposal by means of regression models issued from dynamic simulations  

E-Print Network (OSTI)

comparison between different energy reduction strategies, like improving the insulation levels or increasing the thermal inertia. An example of their use and a data comparison with a dynamic simulation is shown in last;Nowadays, the most reliable solutions to calculate the energy demand are the simulation energy tools

Boyer, Edmond

378

Topography, complex refractive index, and conductivity of graphene layers measured by correlation of optical interference contrast, atomic force, and back scattered electron microscopy  

SciTech Connect

The optical phase shift by reflection on graphene is measured by interference contrast microscopy. The height profile across graphene layers on 300?nm thick SiO{sub 2} on silicon is derived from the phase profile. The complex refractive index and conductivity of graphene layers on silicon with 2?nm thin SiO{sub 2} are evaluated from a phase profile, while the height profile of the layers is measured by atomic force microscopy. It is observed that the conductivity measured on thin SiO{sub 2} is significantly greater than on thick SiO{sub 2}. Back scattered electron contrast of graphene layers is correlated to the height of graphene layers.

Vaupel, Matthias, E-mail: Matthias.vaupel@zeiss.com; Dutschke, Anke [Training Application Support Center, Carl Zeiss Microscopy GmbH, Königsallee 9-21, 37081 Göttingen (Germany); Wurstbauer, Ulrich; Pasupathy, Abhay [Department of Physics, Columbia University New York, 538 West 120th Street, New York, New York 10027 (United States); Hitzel, Frank [DME Nanotechnologie GmbH, Geysostr. 13, D-38106 Braunschweig (Germany)

2013-11-14T23:59:59.000Z

379

IN-SITU MEASUREMENT OF WALL THERMAL PERFORMANCE: DATA INTERPRETATION AND APPARATUS DESIGN RECOMMENDATIONS  

E-Print Network (OSTI)

Unit (ETTU): Field Measurement of Wall Performance, Presented at Third International Symposium on Energy

Modera, M.P.; Sherman, M.H.; de Vinuesa, S.G.

2008-01-01T23:59:59.000Z

380

Pressure Wave Measurements Resulting from Thermal Cook-Off of the HMX Based High Explosive LX-04  

SciTech Connect

Experiments that investigate thermal and nearby explosion scenarios are needed to provide essential data to models for accurate predictions. A porous LX-04 (85/15 wt% HMX/Viton) sample was heated in a heavily confined donor charge until it thermally exploded. The reaction accelerated a steel cover plate across a 10 cm gap into a preheated gauged acceptor cylinder (near its theoretical maximum density) of LX-04. The carbon resistor gauges in the acceptor measured the resulting multi-dimensional ramp wave as it propagated through the pre-heated LX-04. Detonation of the LX-04 acceptor does not occur. Results are compared to similar experiments with acceptors at room temperature.

Garcia, F; Vandersall, K S; Forbes, J W; Tarver, C M; Greenwood, D

2003-07-11T23:59:59.000Z

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


381

Thermal 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

382

Measurement and modeling of thermal properties of sorghum and soy flours  

E-Print Network (OSTI)

Kelvin. Figure 1 shows the OSC conventions for presentation of thermal analysis data. When a transition such as melting, boiling, gelatinization or crystallization occurs in the sample material, an endothermic or exothermic reaction takes place... important than the second scan values. The second scan values, however, can tell us whether endothermic or exothermic transitions occurred in the first scan and 1f these transitions are irreversible. The bas1c methodology for determining specific heat...

Gonzalez Palacios, Lazaro

1981-01-01T23:59:59.000Z

383

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

384

Ferrocenylundecanethiol Self-Assembled Monolayer Charging Correlates with Negative Differential Resistance Measured by Conducting Probe Atomic Force Microscopy  

Science Journals Connector (OSTI)

Additionally, electric force measurements along with theoretical modeling both in and out of contact with a nonelectroactive 1-octanethiol (C8SH) SAM were also performed. ... Using a simple parallel-plate geometry37 and assuming that stored charge is localized on the ferricenium end groups, we find that the quantity of detected charges is Q = 80 ± 20 positive elementary charges or the same number of oxidized molecules if we assume each molecule can store one charge. ... The measurements showed: (1) the I-V traces were linear over ±0.3 V, (2) the junction resistance increased exponentially with alkyl chain length, (3) the junction resistance decreased with increasing load and showed two distinct power law scaling regimes, (4) resistances were a factor of 10 lower for junctions based on benzyl thiol SAMs compared to hexyl thiol SAMs having the same thickness, and (5) the junctions sustained fields up to 2 × 107 V/cm before breakdown. ...

Alexei V. Tivanski; Gilbert C. Walker

2005-05-03T23:59:59.000Z

385

Photo-Thermal Transfer Function of Dielectric Mirrors for Precision Measurements  

E-Print Network (OSTI)

The photo-thermal transfer function from absorbed power incident on a dielectric mirror to the effective mirror position is calculated using the coating design as input. The effect is found to change in amplitude and sign for frequencies corresponding to diffusion length comparable to the coating thickness. Transfer functions are calculated for the $Ti$-doped ${\\rm Ta_2O_5:SiO_2}$ coating used in Advanced LIGO and for a crystalline ${\\rm Al_xGa_{1-x}As}$ coating. The shape of the transfer function at high frequencies is shown to be a sensitive indicator of the effective absorption depth, providing a potentially powerful tool to distinguish coating-internal absorption from surface contamination related absorption. The sign change of the photo-thermal effect could also be useful to stabilize radiation pressure-based opto-mechanical systems. High frequency corrections to the previously published thermo-optic noise estimates are also provided. Finally, estimating the quality of the thermo-optic noise cancellation occurring in fine-tuned ${\\rm Al_xGa_{1-x}As}$ coatings requires the detailed heat flow analysis done in this paper.

Stefan W. Ballmer

2014-11-10T23:59:59.000Z

386

Photo-Thermal Transfer Function of Dielectric Mirrors for Precision Measurements  

E-Print Network (OSTI)

The photo-thermal transfer function from absorbed power incident on a dielectric mirror to the effective mirror position is calculated using the coating design as input. The effect is found to change in amplitude and sign for frequencies corresponding to diffusion length comparable to the coating thickness. Transfer functions are calculated for the $Ti$-doped ${\\rm Ta_2O_5:SiO_2}$ coating used in Advanced LIGO and for a crystalline ${\\rm Al_xGa_{1-x}As}$ coating. The shape of the transfer function at high frequencies is shown to be a sensitive indicator of the effective absorption depth, providing a potentially powerful tool to distinguish coating-internal absorption from surface contamination related absorption. The sign change of the photo-thermal effect could also be useful to stabilize radiation pressure-based opto-mechanical systems. High frequency corrections to the previously published thermo-optic noise estimates are also provided. Finally, estimating the quality of the thermo-optic noise cancellation occurring in fine-tuned ${\\rm Al_xGa_{1-x}As}$ coatings requires the detailed heat flow analysis done in this paper.

Stefan W. Ballmer

2015-01-07T23:59:59.000Z

387

Cryogenic measurements of mechanical loss of high-reflectivity coating and estimation of thermal noise  

Science Journals Connector (OSTI)

We report on low-frequency measurements of the mechanical loss of a high-quality (transmissivity T<5??ppm at ?0=1064??nm, absorption...

Granata, Massimo; Craig, Kieran; Cagnoli, Gianpietro; Carcy, Cécile; Cunningham, William; Degallaix, Jérôme; Flaminio, Raffaele; Forest, Danièle; Hart, Martin; Hennig, Jan-Simon; Hough, James; MacLaren, Ian; Martin, Iain William; Michel, Christophe; Morgado, Nazario; Otmani, Salim; Pinard, Laurent; Rowan, Sheila

2013-01-01T23:59:59.000Z

388

On-line ultrasonic velocity measurements for characterisation of microstructural evaluation during thermal aging of ?-quenched zircaloy-2  

Science Journals Connector (OSTI)

Ultrasonic non-destructive evaluation (NDE) technique has been used for characterisation of evolution of microstructure in ?-quenched and thermally aged zircaloy-2 specimens. On-line ultrasonic velocity measurements have been made in ?-quenched state of zircaloy-2 (A specimen) during heating at different heating rates up to 573 K (B specimen), 603 K (C specimen) and 623 K (D specimen) with holding time periods of 5 h for specimens B and C, and 2 h for specimen D, at the corresponding maximum temperature, by employing a specially designed experimental set-up. The observed change in velocity at room temperature (298 K) before and after ageing for specimens B and D is 0.52% and 0.48%, respectively, and this reveals that intermetallic precipitates are formed during the aging treatment. Ultrasonic measurements are correlated with the hardness, density and microstructural changes.

A. Nishara Begum; V. Rajendran; T. Jayakumar; P. Palanichamy; N. Priyadharsini; S. Aravindan; Baldev Raj

2007-01-01T23:59:59.000Z

389

Calculations of thermal-reactor spent-fuel nuclide inventories and comparisons with measurements  

SciTech Connect

Comparisons with integral measurements have demonstrated the accuracy of CINDER codes and libraries in calculating aggregate fission-product properties, including neutron absorption, decay power, and decay spectra. CINDER calculations have, alternatively, been used to supplement measured integral data describing fission-product decay power and decay spectra. Because of the incorporation of the extensive actinide library and the use of ENDF/B-V data, it is desirable to compare the inventory of individual nuclides obtained from tandem EPRI-CELL/CINDER-2 calculations with those determined in documented benchmark inventory measurements of spent reactor fuel. The development of the popular /sup 148/Nd burnup measurement procedure is outlined, and areas of uncertainty in it and lack of clarity in its interpretation are indicated. Six inventory samples of varying quality and completeness are examined. The power histories used in the calculations have been listed for other users.

Wilson, W.B.; LaBauve, R.J.; England, T.R.

1982-01-01T23:59:59.000Z

390

American Institute of Aeronautics and Astronautics Measurements for fuel reforming for scramjet thermal management and  

E-Print Network (OSTI)

American Institute of Aeronautics and Astronautics 1 Measurements for fuel reforming for scramjet, since even composite materials can't withstand the large heat load found in a Scramjet combustion

Paris-Sud XI, Université de

391

Measurements of the spatial and energy distribution of thermal neutrons in uranium, heavy water lattices  

E-Print Network (OSTI)

Intracell activity distributions were measured in three natural uranium, heavy water lattices of 1. 010 inch diameter, aluminum clad rods on triangular spacings of 4. 5 inches, 5. 0 inches, and 5. 75 inches, respectively, ...

Brown, Paul S. (Paul Sherman)

1962-01-01T23:59:59.000Z

392

Structure and thermal regime beneath the South Pole region, East Antarctica, from magnetotelluric measurements  

Science Journals Connector (OSTI)

......Figure B2 Recordings of electric fields on parallel...a superposition of elementary volumes (e.g. Stratton...spherical distribution of electric charge over the Earth's...of electrode contact resistance on electric field measurements......

Philip E. Wannamaker; John A. Stodt; Louise Pellerin; Steven L. Olsen; Darrell B. Hall

2004-04-01T23:59:59.000Z

393

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

394

Thermal Diffusivity and Viscosity of Suspensions of Disc Shaped Nanoparticles  

E-Print Network (OSTI)

In this work we conduct a transient heat conduction experiment with an aqueous suspension of nanoparticle disks of Laponite JS, a sol forming grade, using laser light interferometry. The image sequence in time is used to measure thermal diffusivity and thermal conductivity of the suspension. Imaging of the temperature distribution is facilitated by the dependence of refractive index of the suspension on temperature itself. We observe that with the addition of 4 volume % of nano-disks in water, thermal conductivity of the suspension increases by around 30%. A theoretical model for thermal conductivity of the suspension of anisotropic particles by Fricke as well as by Hamilton and Crosser explains the trend of data well. In turn, it estimates thermal conductivity of the Laponite nanoparticle itself, which is otherwise difficult to measure in a direct manner. We also measure viscosity of the nanoparticle suspension using a concentric cylinder rheometer. Measurements are seen to follow quite well, the theoretical relation for viscosity of suspensions of oblate particles that includes up to two particle interaction. This result rules out the presence of clusters of particles in the suspension. The effective viscosity and thermal diffusivity data show that the shape of the particle has a role in determining enhancement of thermophysical properties of the suspension.

Susheel S. Bhandari; K. Muralidhar; Yogesh M Joshi

2014-03-05T23:59:59.000Z

395

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

396

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network (OSTI)

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters (1.4 M$_\\odot$, 12 km, 600 Hz), the stellar radius is on the order of 4% larger than the radius inferred under the assumption that the star is not spinning.

Michi Baubock; Feryal Ozel; Dimitrios Psaltis; Sharon M. Morsink

2014-07-11T23:59:59.000Z

397

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network (OSTI)

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters ...

Baubock, Michi; Psaltis, Dimitrios; Morsink, Sharon M

2014-01-01T23:59:59.000Z

398

First Measurements of the Inclined Boron Layer Thermal-Neutron Detector for Reflectometry  

SciTech Connect

A prototype detector based on the inclined boron layer principle is introduced. For typical measurement conditions at the Liquids Reflectometer at the Spallation Neutron Source, its count rate capability is shown to be superior to that of the current detector by nearly two orders of magnitude.

Clonts, Lloyd G [ORNL; Crow, Lowell [ORNL; Van Vuure, Thorwald L [ORNL; Robertson, Lee [ORNL; Riedel, Richard A [ORNL; Richards, John D [ORNL; Cooper, Ronald G [ORNL; Remec, Igor [ORNL; Ankner, John Francis [ORNL; Browning, Jim [ORNL

2010-01-01T23:59:59.000Z

399

COMBINED THERMAL MEASUREMENT AND SIMULATION FOR THE DETAILED ANALYSIS OF FOUR OCCUPIED LOW-ENERGY BUILDINGS  

E-Print Network (OSTI)

-ENERGY BUILDINGS U.D.J. Gieseler, F.D. Heidt1 , W. Bier Division of Building Physics and Solar Energy, University energy and temperature measurements of occupied buildings very well. These buildings repre- sent small to medium size residential low-energy buildings of different construction type, which are typical for mid

Gieseler, Udo D. J.

400

Interaction between Thermal Phonons and Dislocations in LiF  

Science Journals Connector (OSTI)

Thermal conductivity measurements on deformed LiF crystals from 0.04 to 0.8 K have indicated a strong polarization- and frequency-dependent dynamic scattering of thermal phonons by mobile dislocations. Heat-pulse experiments at 3.6 K have verified both the strength and polarization dependence of the scattering mechanism. The scattering of thermal phonons by sessile dislocations was too weak to be detected.

A. C. Anderson and M. E. Malinowski

1972-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Measurements of thermal-hydraulic parameters in liquid-metal-cooled fast-breeder reactors  

SciTech Connect

This paper discusses instrumentation for liquid-metal-cooled fast breeder reactors (LMFBR's). Included is instrumentation to measure sodium flow, pressure, temperature, acoustic noise, sodium purity, and leakage. The paper identifies the overall instrumentation requirements for LMFBR's and those aspects of instrumentation which are unique or of special concern to LMFBR systems. It also gives an overview of the status of instrument design and performance.

Sackett, J.I.

1983-01-01T23:59:59.000Z

402

Gamma-gamma directional correlation measurements in 130,132Xe following thermal neutron capture by natural xenon  

Science Journals Connector (OSTI)

Directional correlations of gamma-ray cascades in 130,132Xe have been measured following thermal n capture by a pressurised natural xenon gas target. Gamma-ray singles spectra were measured up to 5.5 MeV and the coincidence correlation data were obtained for the energy range 0.2-2.5 MeV. Decay schemes were developed on the basis of the coincidence measurements. The data spin-parity assignments to be made to most levels lying below 3.5 MeV in the 132Xe and the multiple mixing ratios to be evaluated for the more intense transitions. The results are fitted to IBM-1 and IBM-2 and are also compared with the prediction of the dynamic deformation model of Kumar (1983). The 23+ level at 1985 keV in 132Xe is considered to be a mixed-symmetry state with B(M1; 23+ to 21+)=0.29 mu N2.

S A Hamada; W D Hamilton; B More

1988-01-01T23:59:59.000Z

403

High-resolution thermal-expansion measurements of tetrathiafulvalenetetracyanoquinodimethane (TTF-TCNQ)  

Science Journals Connector (OSTI)

An analysis of our measurements of the b-axis expansivity ?b of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) within the Debye approximation suggests an unexpectedly high effective Debye temperature (?b=200±30 K) and a large anharmonicity (?=5±1.5) for the low-lying b-axis polarized acoustic phonons. These values for ? and ?b indicate substantial softening of the lattice above 100 K and also suggest an expansivity contribution from intramolecular vibrational modes. No anomalous length changes were observed in the region of the metal-semiconductor transition (45-65 K) to within ?LbLb?3×10-5.

D. E. Schafer; G. A. Thomas; F. Wudl

1975-12-15T23:59:59.000Z

404

Measurements and Standards for Thermoelectric Materials  

E-Print Network (OSTI)

Measurements and Standards for Thermoelectric Materials CERAMICS Our goal is to develop standard, electrical conductivity, thermal conductivity) for thin film and bulk thermoelectric materials to enable the commercialization of these materials. Objective Impact and Customers · Thermoelectric SRMs and measurement methods

405

Variable pressure thermal insulating jacket  

DOE Patents (OSTI)

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

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

1994-09-20T23:59:59.000Z

406

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

407

Conduction cooled tube supports  

DOE Patents (OSTI)

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

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

1984-01-01T23:59:59.000Z

408

Observation and Measurement of Temperature Rise and Distribution on GaAs Photo-cathode Wafer with a 532nm Drive Laser and a Thermal Imaging Camera  

SciTech Connect

Significant temperature rise and gradient are observed from a GaAs photo-cathode wafer irradiated at various power levels with over 20W laser power at 532nm wavelength. The laser power absorption and dissipated thermal distribution are measured. The result shows a clear indication that proper removal of laser induced heat from the cathode needs to be considered seriously when designing a high average current or low quantum efficiency photo-cathode electron gun. The measurement method presented here provides a useful way to obtain information about both temperature and thermal profiles, it also applies to cathode heating study with other heating devices such as electrical heaters.

Shukui Zhang, Stephen Benson, Carlos Hernandez-Garcia

2011-03-01T23:59:59.000Z

409

Melt Rheology and Thermal Stability of Nanoclay Filled Poly(3hydroxybutyrate-co-4hydroxybutyrate) Biocomposites  

Science Journals Connector (OSTI)

Melt apparent shear viscosity for poly(3hydroxybutyrate-co-4hydroxybutyrate) composites filled with nanoclay was measured by means of a capillary...?1..., and thermal stability was conducted on a thermogravimetri...

Jia Yang; Lina Hang; Yahui Dai

2014-09-01T23:59:59.000Z

410

Investigation of Thermal Interface Materials Using Phase-Sensitive Transient Thermoreflectance Technique: Preprint  

SciTech Connect

With increasing power density in electronics packages/modules, thermal resistances at multiple interfaces are a bottleneck to efficient heat removal from the package. In this work, the performance of thermal interface materials such as grease, thermoplastic adhesives and diffusion-bonded interfaces are characterized using the phase-sensitive transient thermoreflectance technique. A multi-layer heat conduction model was constructed and theoretical solutions were derived to obtain the relation between phase lag and the thermal/physical properties. This technique enables simultaneous extraction of the contact resistance and bulk thermal conductivity of the TIMs. With the measurements, the bulk thermal conductivity of Dow TC-5022 thermal grease (70 to 75 um bondline thickness) was 3 to 5 W/(m-K) and the contact resistance was 5 to 10 mm2-K/W. For the Btech thermoplastic material (45 to 80 ?m bondline thickness), the bulk thermal conductivity was 20 to 50 W/(m-K) and the contact resistance was 2 to 5 mm2-K/W. Measurements were also conducted to quantify the thermal performance of diffusion-bonded interface for power electronics applications. Results with the diffusion-bonded sample showed that the interfacial thermal resistance is more than one order of magnitude lower than those of traditional TIMs, suggesting potential pathways to efficient thermal management.

Feng, X.; King, C.; DeVoto, D.; Mihalic, M.; Narumanchi, S.

2014-08-01T23:59:59.000Z

411

THERMAL PROPERTIES OF FIBERBOARD OVERPACK MATERIALS IN THE 9975 SHIPPING PACKAGE  

SciTech Connect

The 9975 shipping package incorporates a cane fiberboard overpack for thermal insulation and impact resistance. Thermal properties (thermal conductivity and specific heat capacity) have been measured on cane fiberboard and a similar wood fiber-based product at several temperatures representing potential storage conditions. While the two products exhibit similar behavior, the measured specific heat capacity varies significantly from prior data. The current data are being developed as the basis to verify that this material remains acceptable over the extended storage time period.

VORMELKER, PHILLIP; DAUGHERTY, W. L.

2005-06-10T23:59:59.000Z

412

Advancing reactive tracer methods for measuring thermal evolution in CO2-and water-based geothermal reservoirs  

Energy.gov (U.S. Department of Energy (DOE))

DOE Geothermal Peer Review 2010 - Presentation. This project aims to develop reactive tracer method for monitoring thermal drawdown in enhanced geothermal systems.

413

Device for thermal transfer and power generation  

DOE Patents (OSTI)

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

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

2011-04-19T23:59:59.000Z

414

Ionizing radiation dosimetry in the absorbed dose range 0.01–50 \\{MGy\\} based on resistance and ESR linewidth measurements of organic conducting crystals  

Science Journals Connector (OSTI)

The materials studied in the present work as high-dose dosimeters are members of a large class of molecular crystals which are organic conductors of electricity. Very different from each other in the details of their molecular and crystal structures, they all behave in the same way when subjected to increasing high doses of radiation, at least from the point of view of their electronic transport properties, because of the quasi-one-dimensional character of the conduction process. Their resistivities increase exponentially with the absorbed dose while their electron spin resonance (ESR) linewidths decrease exponentially. Very small single crystals less than 10 ?m thick can be used as dosimeters in the dose range 0.01–50 \\{MGy\\} for ? rays as well as for electron irradiations, by applying four probe resistance measurements. Only a few compounds over a large number of candidates have been irradiated in the present work with ?-rays, low energy x-rays and electrons. In some favourable cases the energy and temperature dependences of the dosimeters have been checked experimentally. Their mass energy absorption coefficients and electron stopping powers have been also calculated. It is hoped to extend this kind of dosimetry to lower and higher doses by trying new compounds from the large family of organic conductors or by improving the resistivity and ESR measurement techniques.

L. Zuppiroli; S. Bouffard; J.J. Jacob

1985-01-01T23:59:59.000Z

415

Conductive Thermal Interaction in Evaporative Cooling Process  

E-Print Network (OSTI)

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

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

1990-01-01T23:59:59.000Z

416

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network (OSTI)

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

Wang, Zhaojie

2012-01-01T23:59:59.000Z

417

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network (OSTI)

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

Wang, Zhaojie

2012-01-01T23:59:59.000Z

418

Conductive Polymers  

SciTech Connect

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

419

Tunable thermal link  

DOE Patents (OSTI)

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

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

2014-07-15T23:59:59.000Z

420

Temperature dependence of thermal conductivity of AlxGa1-xN thin films measured by the differential 3 technique  

E-Print Network (OSTI)

Device Processing Lab EE 137 Intro to Semiconductor Optoelectronic Devices EE 160 Fiber Optic Control EE 137 Intro to Semiconductor Optoelectronic Devices EE 143 Multimedia Technologies

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Thermal characterisation of a lightweight mortar containing expanded perlite for underground insulation  

Science Journals Connector (OSTI)

This paper aims to investigate the use of expanded perlite in mortar, for further application of shotcrete to thermal insulation of underground mines. Mixes were designed according to the typical proportions of underground shotcrete, with the sand volumetrically substituted by expanded perlite. Tests of samples were conducted at four ages. Transient plane source technique was utilised to measure the thermal properties. The results showed reduced weight, decreased thermal conductivity, deteriorated thermal diffusivity, and sacrificed mechanical strength with perlite addition. Experimental data analysis and explanation in this paper would establish useful fundamentals for further application of expanded perlite to underground shotcrete.

W.V. Liu; D.B. Apel; V. Bindiganavile

2011-01-01T23:59:59.000Z

422

Heat Generation and Flow and Thermal Effects on Optical Spectra in Laser Diode Pumped Thulium-doped Vanadate Crystals  

Science Journals Connector (OSTI)

Optical spectra, excited state relaxation dynamics and thermal conductivity in a wide temperature region for thulium-doped YVO4, GdVO4 and LuVO4 have been measured and analyzed to...

Lisiecki, Radoslaw; Stachowiak, Piotr; Jezowski, Andrzej; Solarz, Piotr; Dominiak-Dzik, Grazyna; Ryba-Romanowski, Witold; Lukasiewicz, Tadeusz

423

Note: A simple model for thermal management in solenoids  

SciTech Connect

We describe a model of the dynamical temperature evolution in a solenoid winding. A simple finite element analysis is calibrated by accurately measuring the thermally induced resistance change of the solenoid, thus obviating the need for accurate knowledge of the mean thermal conductivity of the windings. The model predicts quasi thermal runaway for relatively modest current increases from the normal operating conditions. We demonstrate the application of this model to determine the maximum current that can be safely applied to solenoids used for helium spin-echo measurements.

McIntosh, E. M., E-mail: emb56@cam.ac.uk; Ellis, J. [The Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)] [The Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2013-11-15T23:59:59.000Z

424

National Radio Astronomy Observatory Measurements of Copper Heat Straps Near 4 K  

E-Print Network (OSTI)

as OFHC. When annealed, these materials have very high thermal conductivity, with a maximum measurements of the thermal resistance of heat straps used in the ALMA Band 6 cartridges. The results suggest the contact area is large (~ 10 cm2 ) but that grease actually increases the thermal resistance when

Groppi, Christopher

425

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

426

Feasibility study for measurement of insulation compaction in the cryogenic rocket fuel storage tanks at Kennedy Space Center by fast/thermal neutron techniques  

SciTech Connect

The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Some of the perlite may have compacted over time, compromising the thermal performance and also the structural integrity of the tanks. Neutrons can readily penetrate through the 1.75 cm outer steel shell and through the entire 120 cm thick perlite zone. Neutrons interactions with materials produce characteristic gamma rays which are then detected. In compacted perlite the count rates in the individual peaks in the gamma ray spectrum will increase. Portable neutron generators can produce neutron simultaneous fluxes in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scattering which is sensitive to Si, Al, Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA), which is sensitive to Si, Al, Na, K and H among others. The results of computer simulations using the software MCNP and measurements on a test article suggest that the most promising approach would be to operate the system in time-of-flight mode by pulsing the neutron generator and observing the subsequent die away curve in the PGNA signal.

Livingston, R. A. [Materials Science and Engineering Dept., U. of Maryland, College Park, MD (United States); Schweitzer, J. S. [Physics Dept., U. of Connecticut, Storrs (United States); Parsons, A. M. [Goddard Space Flight Center, Greenbelt (United States); Arens, E. E. [John F. Kennedy Space Center, FL (United States)

2014-02-18T23:59:59.000Z

427

Thermal neutron detection system  

DOE Patents (OSTI)

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

428

Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700  

Science Journals Connector (OSTI)

......epithermal neutron beam for boron neutron capture therapy...separation. INTRODUCTION Boron neutron capture therapy...accumulation of the isotope 10B in tumour tissue...necessary and that for the determination of the ratio R n, a...Carrara M., Borroni M. Determination of gamma dose and thermal......

G. Gambarini; D. Magni; V. Regazzoni; M. Borroni; M. Carrara; E. Pignoli; J. Burian; M. Marek; V. Klupak; L. Viererbl

2014-10-01T23:59:59.000Z

429

October 2011 SDI FEP Issues Heat Conduction Issues (HC)  

E-Print Network (OSTI)

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

430

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

E-Print Network (OSTI)

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

Li, Baowen

431

Measurement of Three Critical Parameters as a Basis for a Simple Thermal Barrier Coating Life Prediction Methodology  

NLE Websites -- All DOE Office Websites (Extended Search)

Three Critical Parameters Three Critical Parameters As A Basis for A Simple Thermal Barrier Coating Life Prediction Methodology University of Connecticut Eric Jordan and Maurice Gell SCIES Project 02- 01- SR 097 DOE COOPERATIVE AGREEMENT DE-FC26-02NT41431 Tom J. George, Program Manager, DOE/NETL Richard Wenglarz, Manager of Research, SCIES Project Awarded (05/01/02, 36 Month Duration) $ 478,495 Total Contract Value ($ 478,495 DOE) Gas Turbine Need * Industrial Gas Turbine Performance & Durability Depend Strongly On Use Of Thermal Barrier Coatings * Aggressive Application of TBCs Limited By Lack of NDI And Lifing Methods University of Connecticut Gas Turbine Need Non-Destructive Assessment of Remaining Life Strongly Impacts Operating Cost * Reduce occurrence of unplanned shut down * Reduce wasteful precautionary part replacement

432

Fission Product Data Measured at Los Alamos for Fission Spectrum and Thermal Neutrons on {sup 239}Pu, {sup 235}U, {sup 238}U  

SciTech Connect

We describe measurements of fission product data at Los Alamos that are important for determining the number of fissions that have occurred when neutrons are incident on plutonium and uranium isotopes. The fission-spectrum measurements were made using a fission chamber designed by the National Institute for Standards and Technology (NIST) in the BIG TEN critical assembly, as part of the Inter-laboratory Liquid Metal Fast Breeder Reactor (LMFBR) Reaction Rate (ILRR) collaboration. The thermal measurements were made at Los Alamos' Omega West Reactor. A related set of measurements were made of fission-product ratios (so-called R-values) in neutron environments provided by a number of Los Alamos critical assemblies that range from having average energies causing fission of 400-600 keV (BIG TEN and the outer regions of the Flattop-25 assembly) to higher energies (1.4-1.9 MeV) in the Jezebel, and in the central regions of the Flattop-25 and Flattop-Pu, critical assemblies. From these data we determine ratios of fission product yields in different fuel and neutron environments (Q-values) and fission product yields in fission spectrum neutron environments for {sup 99}Mo, {sup 95}Zr, {sup 137}Cs, {sup 140}Ba, {sup 141,143}Ce, and {sup 147}Nd. Modest incident-energy dependence exists for the {sup 147}Nd fission product yield; this is discussed in the context of models for fission that include thermal and dynamical effects. The fission product data agree with measurements by Maeck and other authors using mass-spectrometry methods, and with the ILRR collaboration results that used gamma spectroscopy for quantifying fission products. We note that the measurements also contradict earlier 1950s historical Los Alamos estimates by {approx}5-7%, most likely owing to self-shielding corrections not made in the early thermal measurements. Our experimental results provide a confirmation of the England-Rider ENDF/B-VI evaluated fission-spectrum fission product yields that were carried over to the ENDF/B-VII.0 library, except for {sup 99}Mo where the present results are about 4%-relative higher for neutrons incident on {sup 239}Pu and {sup 235}U. Additionally, our results illustrate the importance of representing the incident energy dependence of fission product yields over the fast neutron energy range for high-accuracy work, for example the {sup 147}Nd from neutron reactions on plutonium. An upgrade to the ENDF library, for ENDF/B-VII.1, based on these and other data, is described in a companion paper to this work.

Selby, H.D., E-mail: hds@lanl.go [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mac Innes, M.R.; Barr, D.W.; Keksis, A.L.; Meade, R.A.; Burns, C.J.; Chadwick, M.B.; Wallstrom, T.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2010-12-15T23:59:59.000Z

433

Spin-dependent thermal and electrical transport in a spin-valve system  

SciTech Connect

Within the framework of Bu{close_quotes}ttiker{close_quote}s gauge invariant and charge conservation dc transport theory, the spin-dependent thermal and electrical transport in a ferromagnet-insulator-ferromagnet tunnel junction is investigated at finite bias voltage and finite temperature. It is observed that the relative orientations of magnetizations in the two ferromagnetic (FM) electrodes as well as temperature have remarkable effects on the differential conductance, thermopower, Peltier effect, and thermal conductivity. At low temperature the quantum resonant tunneling is predominant, leading to the deviation of classical transport theory, while the transport of electrons are crucially governed by thermal processes at high temperature. The so-called spin-valve phenomenon is clearly uncovered for both the differential conductance and the thermal conductivity at low temperature. The Wiedemann-Franz law is examined, and the inelastic tunneling spectroscopy is also discussed. Our findings are expected to be measured in the near future.

Wang, Zheng-Chuan; Su, Gang; Gao, Song

2001-06-01T23:59:59.000Z

434

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

E-Print Network (OSTI)

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

Glaeser, A M

2008-01-01T23:59:59.000Z

435

Measurement of the energy, multiplicity and angular correlation of ?-rays from the thermal neutron capture reaction Gd(n, ?) using JPARC-ANNRI  

SciTech Connect

We conducted an experiment using the JPARC-ANNRI spectrometer to measure the energy, multiplicity and correlation of ?-rays from the neutron capture of natural gadolinium. We incorporated the GEANT4 Monte Carlo (MC) simulation into the detector, and compared the data with the results of the MC simulation. We report our data analysis and compare our data with those obtained by the MC simulation.

Ou, Iwa; Yamada, Yoshiyuki; Yano, Takatomi; Mori, Takaaki; Kayano, Tsubasa; Sakuda, Makoto [Department of Physics, Okayama University, Okayama, 700-8530 (Japan); Kimura, Atsushi; Harada, Hideo [Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan)

2014-05-02T23:59:59.000Z

436

Optimum design of on-line measurements of thermophysical properties using temperature oscillation techniques  

SciTech Connect

The presented temperature oscillation techniques operate in a steady-periodic mode independent of initial conditions. They are used for on-line measurement of thermal diffusivity, conductivity and specific heat of liquids. Peltier-elements generate a periodic temperature oscillation at the outer surface of a reference layer, which is in contact with the liquid specimen. The temperature wave propagates through the reference layer into the specimen. The thermal diffusivity of the specimen is deduced by measuring and evaluating the amplitude attenuation and/or the phase shift between the fundamental temperature oscillation at the surface of the liquid specimen and at a well defined position inside the specimen. If the thermal diffusivity of the specimen is known, the thermal conductivity is determined by the measured amplitude attenuation and/or the phase shift between the fundamental temperature oscillation at both surfaces of the reference layer, one of which is in contact with the liquid specimen. With additional measurement of the density the specific heat capability is evaluated from thermal diffusivity and conductivity. Slab and semi-infinite body geometries are considered. The direct heat conduction problem is solved to specify the optimum design of the measurement apparatus by means of sensitivity coefficient studies. Measurement cells are designed and, to confirm the practical applicability, experiments are carried out with different liquids. Measured thermal diffusivities agree very well, and thermal conductivities and specific heat capacities reasonably well with data from the literature.

Czarnetzki, W.; Roetzel, W. [Univ. der Bundeswehr Hamburg (Germany)

1995-12-31T23:59:59.000Z

437

Measurement of thermally induced vibrations of microelectronic devices by use of a heterodyne electronic speckle pattern interferometry imaging technique  

Science Journals Connector (OSTI)

An imaging technique to measure modulated surface displacements on microelectronic devices is presented. A device is supplied by a sinusoidal current that creates a modulated variation...

Grauby, Stéphane; Dilhaire, Stefan; Jorez, Sébastien; Lopez, Luis David Patino; Rampnoux, Jean-Michel; Claeys, Wilfrid

2003-01-01T23:59:59.000Z

438

Thermal Energy Storage in Metal Foams filled with Paraffin Wax.  

E-Print Network (OSTI)

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

Vadwala, Pathik

2012-01-01T23:59:59.000Z

439

Development of a compact thermal lithium atom beam source for measurements of electron velocity distribution function anisotropy in electron cyclotron resonance plasmas  

SciTech Connect

The anisotropy of the electron velocity distribution function (EVDF) in plasmas can be deduced from the polarization of emissions induced by anisotropic electron-impact excitation. In this paper, we develop a compact thermal lithium atom beam source for spatially resolved measurements of the EVDF anisotropy in electron cyclotron resonance (ECR) plasmas. The beam system is designed such that the ejected beam has a slab shape, and the beam direction is variable. The divergence and flux of the beam are evaluated by experiments and calculations. The developed beam system is installed in an ECR plasma device with a cusp magnetic field, and the LiI 2s–2p emission (670.8 nm) is observed in low-pressure helium plasma. The two-dimensional distributions of the degree and direction of the polarization in the LiI emission are measured by a polarization imaging system. The evaluated polarization distribution suggests the spatial variation of the EVDF anisotropy.

Nishioka, T.; Shikama, T.; Nagamizo, S.; Fujii, K.; Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 615-8540 (Japan)] [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 615-8540 (Japan); Zushi, H. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan)] [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Uchida, M.; Tanaka, H.; Maekawa, T. [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Kyoto 606-8502 (Japan)] [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Kyoto 606-8502 (Japan); Iwamae, A. [Research Center for Development of Far-Infrared Region, Fukui University, Fukui 910-8507 (Japan)] [Research Center for Development of Far-Infrared Region, Fukui University, Fukui 910-8507 (Japan)

2013-07-15T23:59:59.000Z

440

Sampling artifacts from conductive silicone tubing  

NLE Websites -- All DOE Office Websites (Extended Search)

Sampling artifacts from conductive silicone tubing Sampling artifacts from conductive silicone tubing Title Sampling artifacts from conductive silicone tubing Publication Type Journal Article Year of Publication 2009 Authors Timko, Michael T., Zhenhong Yu, Jesse Kroll, John T. Jayne, Douglas R. Worsnop, Richard C. Miake-Lye, Timothy B. Onasch, David Liscinsky, Thomas W. Kirchstetter, Hugo Destaillats, Amara L. Holder, Jared D. Smith, and Kevin R. Wilson Journal Aerosol Science and Technology Volume 43 Issue 9 Pagination 855-865 Date Published 06/03/2009 Abstract We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: (1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and (2) silicone tubing emits organic contaminants containing siloxane that are adsorbed onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and the tubing should, therefore, be used with caution. Contamination associated with the use of silicone tubing was observed at ambient temperature and, in some cases, was enhanced by mild heating (<70°C) or pre-exposure to a solvent (methanol). Further evaluation is warranted to quantify systematically how the contamination responds to variations in system temperature, physicochemical particle properties, exposure to solvent, sample contact time, tubing age, and sample flow rates.

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

From the 2nd Law of Thermodynamics to ACConductivity Measures of Interacting  

E-Print Network (OSTI)

From the 2nd Law of Thermodynamics to AC�Conductivity Measures of Interacting Fermions for free fermions with disorder. Such excitation measures result from the 2nd law of thermodynamics � of the phenomenon of electrical conductivity. Contents 1 Introduction 2 2 2nd Law of Thermodynamics and Thermal

442

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

NLE Websites -- All DOE Office Websites (Extended Search)

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

443

Transition Region Emission and Energy Input to Thermal Plasma During the Impulsive Phase of Solar Flares  

E-Print Network (OSTI)

The energy released in a solar flare is partitioned between thermal and non-thermal particle energy and lost to thermal conduction and radiation over a broad range of wavelengths. It is difficult to determine the conductive losses and the energy radiated at transition region temperatures during the impulsive phases of flares. We use UVCS measurements of O VI photons produced by 5 flares and subsequently scattered by O VI ions in the corona to determine the 5.0 thermal energy and the conductive losses deduced from RHESSI and GOES X-ray data using areas from RHESSI images to estimate the loop volumes, cross-sectional areas and scale lengths. The transition region luminosities during the impulsive phase exceed the X-ray luminosities for the first few minutes, but they are smaller than the rates of increase of thermal energy unless the filling factor of the X-ray emitting gas is ~ 0.01. The estimated conductive losses from the hot gas are too large to be balanced by radiative losses or heating of evaporated plasma, and we conclude that the area of the flare magnetic flux tubes is much smaller than the effective area measured by RHESSI during this phase of the flares. For the 2002 July 23 flare, the energy deposited by non-thermal particles exceeds the X-ray and UV energy losses and the rate of increase of the thermal energy.

J. C. Raymond; G. Holman; A. Ciaravella; A. Panasyuk; Y. -K. Ko; J. Kohl

2007-01-12T23:59:59.000Z

444

hal-00111982,version2-9May2007 Effect of measurement probes upon the conductance of an interacting nano-system  

E-Print Network (OSTI)

nano-system: Detection of an attached ring by non local many body effects Axel Freyn and Jean-sur-Yvette Cedex, France We consider a nano-system connected to measurement probes via leads. When a magnetic flux is varied through a ring attached to one lead at a distance Lc from the nano-system, the effective nano

Paris-Sud XI, Université de

445

American National Standard ANSI/ANS-8.6: Safety in conducting subcritical neutron-multiplication measurements {open_quote}In Situ{close_quote}  

SciTech Connect

Safe and economical operations with fissile materials require knowledge of the subcriticality of configurations that arise in material processing, storage, and transportation. Data from critical experiments have been a principal source of information with which to establish safety margins. However, the lower cost and the expediency of performing confirmatory subcritical measurements on the process floor or in the storage vault resulted in much of the early criticality safety guidance being based on subcritical in situ experiments.

McLaughlin, T.P.

1996-10-01T23:59:59.000Z

446

Measurement of natural radioactivity and radon exhalation rate in fly ash samples from a thermal power plant and estimation of radiation doses  

Science Journals Connector (OSTI)

Fly ash produced by coal-burning in thermal power station has become a subject of world wide interest in recent years because of its diverse uses in construction activities and considerable economic and environmental importance. Fly ash is used in the production of bricks, sheets, cement and also in land filling etc. Indian coals used in thermal power plants are found to have high ash contents, resulting in the production of large amount of fly ash. Coal contains radionuclides including uranium (the source of inert gas radon), Th and K. Thus coal combustion results in enhanced concentration of natural radionuclides 226Ra, 232Th and 40K. Since these radionuclides concentration in fly ash plays an important role in health physics it is important to measure radionuclides concentration in fly ash. In the present work enhanced radioactivity and radon exhalation rate from fly ash samples collected from a thermal power plant of NTPC (National Thermal Power Corporation), Dadri (U.P.) India, have been measured. A high resolution gamma ray spectroscopic system has been used for the measurement of natural radioactivity (226Ra, 232Th and 40K). Gamma spectrometric measurements were carried out at Inter-University Accelerator Centre, New Delhi using a coaxial n-type \\{HPGe\\} detector (EG&G, ORTEC, Oak Ridge, USA). Activity concentration of 226Ra varies from 81.8 ± 2.2 to 177.3 ± 10.0 Bq kg?1 with an average value of 118.6 ± 7.4 Bq kg?1 and of 232Th from 111.6 ± 3.2 to 178.5 ± 3.9 Bq kg?1 with an average value of 147.0 ± 3.4 Bq kg?1. 40K activity was found to be below detection limit in some samples while other samples have shown potassium activity to vary from 365.9 ± 4.8 to 495.9 ± 6.2 Bq kg?1 with an average value of 352.0 ± 4.5 Bq kg?1. Surface radon exhalation rates (EA) and Mass exhalation rates (EM) in these samples were measured by “Sealed can technique” using LR-115 type II track detectors. EA is found to vary from 80.1 ± 9.3 to 242.7 ± 16.3 mBq m?2 h?1 with an average value 155.5 ± 12.8 mBq m?2 h?1, while EM varies from 3.1 ± 0.4 to 9.3 ± 0.6 mBq kg?1 h?1 with an average value of 6.0 ± 0.5 mBq kg?1 h?1. Radium equivalent activity (Raeq), related to the external gamma dose and internal dose due to radon and its daughters range from 283.2 to 422.4 Bq kg?1 with an average value of 353.9 Bq kg?1. The calculated values of external hazard index (Hex) vary from 0.77 to 1.87 with an average value of 1.03. Most of the samples show the value of Raeq close to the allowed upper limit of 370 Bq kg?1 and Hex close to unity respectively except in two samples. Annual effective dose varies from 0.15 to 0.23 mSv y?1 with an average value 0.19 mSv y?1.

Mamta Gupta; Ajay Kumar Mahur; Rati Varshney; R.G. Sonkawade; K.D. Verma; Rajendra Prasad

2013-01-01T23:59:59.000Z

447

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

448

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

449

Thermal ignition combustion system  

DOE Patents (OSTI)

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

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

1988-04-19T23:59:59.000Z

450

Thermal ignition combustion system  

SciTech Connect

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

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

1988-01-01T23:59:59.000Z

451

Thermal ignition combustion system  

SciTech Connect

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

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

1988-04-19T23:59:59.000Z

452

Thermal Energy Measurement with Tangential Paddlewheel Flow Meters: Summary of Experimental Results and in-situ Diagnostics  

E-Print Network (OSTI)

paddlewheel flow meters, and several new methods for in-situ diagnostic measures for ascertaining whether or not a flow meter is experiencing fluctuating flow conditions or if a flow meter is suffering a degraded signal due to shaft wear. INTRODUCTION Flow... section where it passes across the candidate sensor that is placed in the inter-changeable test section, through the orifice plate and finally into the is combined with Btu meter the threshold can be much higher than the published threshold of the flow...

Haberl, J. S.; Watt, J. B.

1994-01-01T23:59:59.000Z

453

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

454

Thermal emission of neutron stars with internal heaters  

Science Journals Connector (OSTI)

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

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

2014-01-01T23:59:59.000Z

455

Student Affairs STUDENT CONDUCT  

E-Print Network (OSTI)

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

Suzuki, Masatsugu

456

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

457

Sampling Artifacts from Conductive Silicone Tubing  

SciTech Connect

We report evidence that carbon impregnated conductive silicone tubing used in aerosol sampling systems can introduce two types of experimental artifacts: 1) silicon tubing dynamically absorbs carbon dioxide gas, requiring greater than 5 minutes to reach equilibrium and 2) silicone tubing emits organic contaminants containing siloxane that adsorb onto particles traveling through it and onto downstream quartz fiber filters. The consequence can be substantial for engine exhaust measurements as both artifacts directly impact calculations of particulate mass-based emission indices. The emission of contaminants from the silicone tubing can result in overestimation of organic particle mass concentrations based on real-time aerosol mass spectrometry and the off-line thermal analysis of quartz filters. The adsorption of siloxane contaminants can affect the surface properties of aerosol particles; we observed a marked reduction in the water-affinity of soot particles passed through conductive silicone tubing. These combined observations suggest that the silicone tubing artifacts may have wide consequence for the aerosol community and should, therefore, be used with caution. Gentle heating, physical and chemical properties of the particle carriers, exposure to solvents, and tubing age may influence siloxane uptake. The amount of contamination is expected to increase as the tubing surface area increases and as the particle surface area increases. The effect is observed at ambient temperature and enhanced by mild heating (<100 oC). Further evaluation is warranted.

Timko, Michael T.; Yu, Zhenhong; Kroll, Jesse; Jayne, John T.; Worsnop, Douglas R.; Miake-Lye, Richard C.; Onasch, Timothy B.; Liscinsky, David; Kirchstetter, Thomas W.; Destaillats, Hugo; Holder, Amara L.; Smith, Jared D.; Wilson, Kevin R.

2009-05-15T23:59:59.000Z

458

Fire tests on defective tank-car thermal protection systems  

Science Journals Connector (OSTI)

Many railway tank-cars carrying hazardous materials are thermally protected from fire impingement by thermal insulation and a steel jacket applied to the outside of the tank-car shell. Over time, it is possible that the thermal insulation will sag, rip, degrade, or be crushed under the steel jacket. A thermographic technique to determine whether or not a tank has insulation deficiencies has been developed, but it is necessary to determine which thermal deficiencies do not affect a tank’s survivability in a fire and which thermal deficiencies must be repaired. In order to develop a guideline in assessing thermal defects, a thermal model and experimental data would be beneficial. A series of fire tests were performed on a quarter-section tank-car mock-up to assist in developing a guideline and to provide validation data for a thermal model. Twelve fire tests, with constant, credible, simulated pool fire conditions, were performed on the tank-car mock-up with various insulation deficiencies. An infrared thermal imaging camera was used to measure the tank wall temperature. The thermal images were useful in determining the temperature profiles across the defects at different times and the transient temperature behaviour at different locations. It was seen that the properly installed thermal protection system significantly reduced the heat transfer from the fire to the tank wall. It was also seen that the steel jacket alone (i.e. 100% defect) acted as a radiation shield and provided a significant level of protection. With small defects, it was observed that the surrounding protected material provided a cooling effect by thermal conduction. A square defect greater than about 40 cm on each side should be considered significant, because unlike smaller defects, there is little benefit from the surrounding material as far as the peak defect temperature is concerned.

J.D.J VanderSteen; A.M Birk

2003-01-01T23:59:59.000Z

459

Thermal and Electrical Transport in Oxide Heterostructures  

E-Print Network (OSTI)

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

Ravichandran, Jayakanth

2011-01-01T23:59:59.000Z

460

Measurement  

NLE Websites -- All DOE Office Websites (Extended Search)

localization that limits the present measurements. The knowledge thus gained will have input not only to fusion research, but to may ques- tions of basic plasma physics....

Note: This page contains sample records for the topic "thermal conductivity measurements" 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

Measurement  

NLE Websites -- All DOE Office Websites (Extended Search)

in the Department of Physics & Astronomy. Chapel Hill 2005 Approved: A. E. Champagne, Advisor J. C. Blackmon, Reader C. Iliadis, Reader ABSTRACT Ryan P. Fitzgerald: Measurement of...

462

Effect of current compliance and voltage sweep rate on the resistive switching of HfO{sub 2}/ITO/Invar structure as measured by conductive atomic force microscopy  

SciTech Connect

The electrical characterization of HfO{sub 2}/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO{sub 2} surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO{sub 2}/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

Wu, You-Lin, E-mail: ylwu@ncnu.edu.tw; Liao, Chun-Wei [Department of Electrical Engineering, National Chi Nan University, Puli, Nantou, Taiwan (China); Ling, Jing-Jenn [Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Puli, Nantou, Taiwan (China)

2014-06-16T23:59:59.000Z

463

Thermal management of nanoelectronics  

E-Print Network (OSTI)

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

464

Thermal desorption for passive dosimeter  

E-Print Network (OSTI)

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

Liu, Wen-Chen

1981-01-01T23:59:59.000Z

465

Preliminary requirements for thermal storage subsystems in solar thermal applications  

SciTech Connect

Methodologies for the analysis of value and comparing thermal storage concepts are presented. Value is a measure of worth and is determined by the cost of conventional fuel systems. Value data for thermal storage in large solar thermal electric power applications are presented. Thermal storage concepts must be compared when all are performing the same mission. A method for doing that analysis, called the ranking index, is derived. Necessary data to use the methodology are included.

Copeland, R.J.

1980-04-01T23:59:59.000Z

466

Thermal Dosimetry and Temperature Measurements  

Science Journals Connector (OSTI)

...CCD camera (Cascade:512F, Photometrics, Tucson, AZ). The microscope is composed of (a) 455-nm blue light-emitting diode (Luxeon LXHL-MRRC, Lumileds Lighting, San Jose, CA), (b) exciter filter (455/70, Chroma Technology...

D. A. Christensen

1979-06-01T23:59:59.000Z

467

Thermal Dosimetry and Temperature Measurements  

Science Journals Connector (OSTI)

...N-acetyl-dihydrosphingosine; DAG, diacylglycerol; DETAPAC, diethylenetriamine pentaacetic acid; LED, light-emitting diode; LSM, low-serum medium; LY-R, L5178Y-R; PDT, photodynamic treatment; SAPK, stress-activated protein...

D. A. Christensen

1979-06-01T23:59:59.000Z

468

Code of Conduct  

NLE Websites -- All DOE Office Websites (Extended Search)

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

469

JLF Conduct of Operations  

NLE Websites -- All DOE Office Websites (Extended Search)

Jupiter Laser Facility (JLF) Conduct Of Operations The Conduct of Operations is a set of procedures and guidelines that are put in place to ensure operational safety and security...

470

Correlating the NMR self-diffusion and relaxation measurements with ionic conductivity in polymer electrolytes composed of cross-linked poly(ethylene oxide-propylene oxide) doped with LiN(SO 2 CF 3 ) 2  

Science Journals Connector (OSTI)

A solvent-free solid-polymer electrolyte based on a cross-linked poly(ethylene oxide-propylene oxide) random copolymer doped with LiN(SO 2 CF 3 ) 2 was studied using multinuclear NMR and ionic conductivity. The NMR spin-lattice relaxation times T 1 of the bulk polymer ( 1 H ) the lithium ion ( 7 Li ) and the anion ( 19 F ) were analyzed using single exponential analysis above the glass transition temperatures. Since the temperature dependent 1 H and 7 Li NMR T 1 values had minima the reorientational correlation times were obtained for the segmental motion of the CH 2 CH 2 O/ CH 2 CH ( CH 3 ) O moiety of the bulk polymer and the hopping motion of the lithium ions correlated with the segmental motion. The spin–spin relaxation of the anion signals appeared single exponential with respect to time whereas that of the polymer and the lithium echo signals were at least bi-exponential. Since both the spin-lattice and spin–spin relaxation of the anion indicated a single component the self-diffusion coefficients D were measured using 19 F pulsed-gradient spin-echo (PGSE) NMR measurements. Although the PGSE attenuation data appeared single exponential at each value of the separation between the gradient pulses ? the measured D values had a ? -dependence. Phenomenologically the anion diffuses quicker in a shorter range and the activation energy of the shorter-time diffusion is smaller than that of the longer-time diffusion. The apparent self-diffusion coefficients became smaller for longer ? and approached a constant when ? was longer than 0.05 s. The mean square displacements of the anion were inconsistent with standard diffusion models including “anomalous diffusion” as found for a neutral particle diffusing in a fractal network [i.e. ?r 2 (?)??? ? with ?<1(??2/d w where d w is the random walk fractal dimension)]. The apparent diffusion coefficients of the lithium ions at ?=0.02? s are almost independent of temperature and smaller than the corresponding diffusion coefficients of the anion. Since the activation energy of the anion determined for ? longer than 0.05 s correlates well with those obtained from the ionic conductivity the ion conduction in the solid-polymer medium is driven mainly by fast transfer of the anions.

Kikuko Hayamizu; Yuichi Aihara; William S. Price

2000-01-01T23:59:59.000Z

471

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

E-Print Network (OSTI)

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

Henry, Asegun

472

Electrically conductive composite material  

DOE Patents (OSTI)

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

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

1989-05-23T23:59:59.000Z

473

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

E-Print Network (OSTI)

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

Maruyama, Shigeo

474

CONDUCT OF OPERATIONS (CO)  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

475

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

476

Viscosity and termal conductivity of nanofluids containing mult-walled carbon nanotubes stabilized by chitosan.  

SciTech Connect

Thermal conductivity, viscosity, and stability of nanofluids containing multi-walled carbon nanotubes (MWCNTs) stabilized by cationic chitosan were studied. Chitosan with weight fraction of 0.1%, 0.2 wt%, and 0.5 wt% was used to disperse stably MWCNTs in water. The measured thermal conductivity showed an enhancement from 2.3% to 13% for nanofluids that contained from 0.5 wt% to 3 wt% MWCNTs (0.24 to 1.43 vol %). These values are significantly higher than those predicted using the Maxwell's theory. We also observed that the enhancements were independent of the base fluid viscosity. Thus, use of microconvection effect to explain the anomalous thermal conductivity enhancement should be reconsidered. MWCNTs can be used either to enhance or reduce the fluid base viscosity depending on the weight fractions. In the viscosity-reduction case, a reduction up to 20% was measured by this work. In the viscosity-enhancement case, the fluid behaved as a non-Newtonian shear-thinning fluid. By assuming that MWCNT nanofluids behave as a generalized second grade fluid where the viscosity coefficient depends upon the rate of deformation, a theoretical model has been developed. The model was found to describe the fluid behavior very well.

Tran, P.X.: Massoudi, M: Chen, R.H.

2011-01-01T23:59:59.000Z

477

LoCuSS: A COMPARISON OF CLUSTER MASS MEASUREMENTS FROM XMM-NEWTON AND SUBARU-TESTING DEVIATION FROM HYDROSTATIC EQUILIBRIUM AND NON-THERMAL PRESSURE SUPPORT  

SciTech Connect

We compare X-ray hydrostatic and weak-lensing mass estimates for a sample of 12 clusters that have been observed with both XMM-Newton and Subaru. At an over-density of DELTA = 500, we obtain 1 - M {sup X}/M {sup WL} = 0.01 +- 0.07 for the whole sample. We also divided the sample into undisturbed and disturbed sub-samples based on quantitative X-ray morphologies using asymmetry and fluctuation parameters, obtaining 1 - M {sup X}/M {sup WL} = 0.09 +- 0.06 and -0.06 +- 0.12 for the undisturbed and disturbed clusters, respectively. In addition to non-thermal pressure support, there may be a competing effect associated with adiabatic compression and/or shock heating which leads to overestimate of X-ray hydrostatic masses for disturbed clusters, for example, in the famous merging cluster A1914. Despite the modest statistical significance of the mass discrepancy, on average, in the undisturbed clusters, we detect a clear trend of improving agreement between M {sup X} and M {sup WL} as a function of increasing over-density, M{sup X}/M{sup WL}=(0.908+-0.004)+(0.187+-0.010){center_dot} log{sub 10}(DELTA/500). We also examine the gas mass fractions, f{sub gas} = M {sup gas}/M {sup WL}, finding that they are an increasing function of cluster radius, with no dependence on dynamical state, in agreement with predictions from numerical simulations. Overall, our results demonstrate that XMM-Newton and Subaru are a powerful combination for calibrating systematic uncertainties in cluster mass measurements.

Zhang, Yu-Ying [Argelander-Institut fuer Astronomie, Universitaet Bonn, A