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1

Thermal conductivity measurements of Summit polycrystalline silicon.  

SciTech Connect (OSTI)

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

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

2006-11-01T23:59:59.000Z

2

Measuring Thermal Transport in Extreme Environments: Thermal Conductivity  

E-Print Network [OSTI]

Chen California Institute of Technology Jackie Li University of Michigan supported by CarnegieMeasuring Thermal Transport in Extreme Environments: Thermal Conductivity of Water Ice VII to 20 GPa David G. Cahill, Wen-Pin Hsieh, Dallas Trinkle, University of Illinois at Urbana-Champaign Bin

Braun, Paul

3

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

4

In-Pile Thermal Conductivity Measurement Method for Nuclear Fuels  

SciTech Connect (OSTI)

Thermophysical properties of advanced nuclear fuels and materials during irradiation must be known prior to their use in existing, advanced, or next generation reactors. Thermal conductivity is one of the most important properties for predicting fuel and material performance. A joint Utah State University (USU) / Idaho National Laboratory (INL) project, which is being conducted with assistance from the Institute for Energy Technology at the Norway Halden Reactor Project, is investigating in-pile fuel thermal conductivity measurement methods. This paper focuses on one of these methods – a multiple thermocouple method. This two-thermocouple method uses a surrogate fuel rod with Joule heating to simulate volumetric heat generation to gain insights about in-pile detection of thermal conductivity. Preliminary results indicated that this method can measure thermal conductivity over a specific temperature range. This paper reports the thermal conductivity values obtained by this technique and compares these values with thermal property data obtained from standard thermal property measurement techniques available at INL’s High Test Temperature Laboratory. Experimental results and material properties data are also compared to finite element analysis results.

Joy L. Rempe; Brandon Fox; Heng Ban; Joshua E. Daw; Darrell L. Knudson; Keith G. Condie

2009-08-01T23:59:59.000Z

5

VALIDATION OF A THERMAL CONDUCTIVITY MEASUREMENT SYSTEM FOR FUEL COMPACTS  

SciTech Connect (OSTI)

A high temperature guarded-comparative-longitudinal heat flow measurement system has been built to measure the thermal conductivity of a composite nuclear fuel compact. It is a steady-state measurement device designed to operate over a temperature range of 300 K to 1200 K. No existing apparatus is currently available for obtaining the thermal conductivity of the composite fuel in a non-destructive manner due to the compact’s unique geometry and composite nature. The current system design has been adapted from ASTM E 1225. As a way to simplify the design and operation of the system, it uses a unique radiative heat sink to conduct heat away from the sample column. A finite element analysis was performed on the measurement system to analyze the associated error for various operating conditions. Optimal operational conditions have been discovered through this analysis and results are presented. Several materials have been measured by the system and results are presented for stainless steel 304, inconel 625, and 99.95% pure iron covering a range of thermal conductivities of 10 W/m*K to 70 W/m*K. A comparison of the results has been made to data from existing literature.

Jeff Phillips; Colby Jensen; Changhu Xing; Heng Ban

2011-03-01T23:59:59.000Z

6

Design of a steady state thermal conductivity measurement device for CNT RET polymer composites  

E-Print Network [OSTI]

NY: Taylor & Francis. [10] Tritt, T. M. (2004). MeasurementBulk Materials. In T. M. Tritt, Thermal Conductivity Theory,

Louie, Brian Ming

2011-01-01T23:59:59.000Z

7

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.

8

Spatially localized measurement of thermal conductivity using a hybrid photothermal technique  

SciTech Connect (OSTI)

A photothermal technique capable of measuring thermal conductivity with micrometer lateral resolution is presented. This technique involves measuring separately the thermal diffusivity, D, and thermal effusivity, e, to extract the thermal conductivity, k=(e2/D)1/2. To generalize this approach, sensitivity analysis was conducted for materials having a range of thermal conductivities. Experimental validation was sought using two substrate materials, SiO2 and CaF2, both coated with thin titanium films. The measured conductivities compare favorably with literature values.

David H Hurley; Marat Khafizov; Zilong Hua; Rory Kennedy; Heng Ban

2012-05-01T23:59:59.000Z

9

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

10

Thermal conductivity measurements of insulators for fusion blankets  

SciTech Connect (OSTI)

Alumina-silica mat (8 lb/ft/sup 3/) varied in thermal conductivity in air and Ar from 0.06 W/m- K at 300/sup 0/C to 0.22 W/m- K at 1000/sup 0/C, but in He it increased to 0.24 W/m- K at 300/sup 0/C and 0.54 W/m- K at 1000/sup 0/C, while in steam it was about midway between these values. The carbon and graphite felts behaved similarly, but the rigid and denser (24 lb/ft/sup 3/) zirconia fiberboard exhibited superior insulating properties: 0.07 W/m- K at 300/sup 0/C and 0.14 W/m- K at 1000/sup 0/C in air and Ar, and 0.13 W/m- K at 300/sup 0/C and 0.17 W/m- K at 1000/sup 0/C in steam, but rising to 0.15 W/m- K at 300/sup 0/C and 0.49 W/m- K at 1000/sup 0/C in He. The lighter zirconia felt (14 lb/ft/sup 3/) in steam at 1000/sup 0/C was thought to be best at 0.23 W/m- K and only 0.40 W/m- K in He at 1000/sup 0/C.

Horn, F.L.; Fillo, J.A.; Powell, J.R.

1981-01-01T23:59:59.000Z

11

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

E-Print Network [OSTI]

line heat source method, the thermal con- ductivities of a jelly model (unflavored jelly), sugar solution and some commercial jelly products were measured. The studies were conducted in the temperature range from 25 to 95 'C. Thermal conductivity... were developed from experimental data for unflavored jelly and sugar solutions to predict the thermal conductivity of commercially available fruit jellies at various moisture contents. The predicted values obtained were statistically compared...

Chen, Yih-Rong

1985-01-01T23:59:59.000Z

12

Thermal Conductivity Spectroscopy Technique to Measure Phonon Mean Free Paths  

E-Print Network [OSTI]

Size effects in heat conduction, which occur when phonon mean free paths (MFPs) are comparable to characteristic lengths, are being extensively explored in many nanoscale systems for energy applications. Knowledge of MFPs ...

Schmidt, A. J.

13

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

14

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

SciTech Connect (OSTI)

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

Wang, H

2003-04-15T23:59:59.000Z

15

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

SciTech Connect (OSTI)

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

Williams, Colin F.; Sass, John H.

1996-01-24T23:59:59.000Z

16

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

SciTech Connect (OSTI)

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

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

2014-04-15T23:59:59.000Z

17

Thermal conductivity of thermal-battery insulations  

SciTech Connect (OSTI)

The thermal conductivities of a variety of insulating materials used in thermal batteries were measured in atmospheres of argon and helium using several techniques. (Helium was used to simulate the hydrogen atmosphere that results when a Li(Si)/FeS{sub 2} thermal battery ages.) The guarded-hot-plate method was used with the Min-K insulation because of its extremely low thermal conductivity. For comparison purposes, the thermal conductivity of the Min-K insulating board was also measured using the hot-probe method. The thermal-comparator method was used for the rigid Fiberfrax board and Fiberfrax paper. The thermal conductivity of the paper was measured under several levels of compression to simulate the conditions of the insulating wrap used on the stack in a thermal battery. The results of preliminary thermal-characterization tests with several silica aerogel materials are also presented.

Guidotti, R.A.; Moss, M.

1995-08-01T23:59:59.000Z

18

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

SciTech Connect (OSTI)

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

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

2014-10-15T23:59:59.000Z

19

Uncertainty Analysis on the Design of Thermal Conductivity Measurement by a Guarded Cut-Bar Technique  

SciTech Connect (OSTI)

A technique adapted from the guarded-comparative-longitudinal heat flow method was selected for the measurement of the thermal conductivity of a nuclear fuel compact over a temperature range characteristic of its usage. This technique fulfills the requirement for non-destructive measurement of the composite compact. Although numerous measurement systems have been created based on the guarded comparative method, comprehensive systematic (bias) and measurement (precision) uncertainty associated with this technique have not been fully analyzed. In addition to the geometric effect in the bias error, which has been analyzed previously, this paper studies the working condition which is another potential error source. Using finite element analysis, this study showed the effect of these two types of error sources in the thermal conductivity measurement process and the limitations in the design selection of various parameters by considering their effect on the precision error. The results and conclusions provide valuable reference for designing and operating an experimental measurement system using this technique.

Jeff Phillips; Changhu Xing; Colby Jensen; Heng Ban1

2011-07-01T23:59:59.000Z

20

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

E-Print Network [OSTI]

Measurement of the electronic thermal conductance channels and heat capacity of graphene at low, Gwf , test the Wiedemann-Franz (wf) law, and infer the electronic heat capacity, with a minimum value of a Coulomb-interacting electron-hole plasma may result in deviations from the Fermi-liquid values of the Mott

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

Photothermal measurement of the thermal conductivity of supercooled water O. Benchikh, D. Fournier, A. C. Boccara  

E-Print Network [OSTI]

Thermal diffusivity measurements of supercooled water have been performed between + 40 °C and - 23 °C properties of supercooled water have been measured [1 ]. However, the thermal conduc- Article published

Boyer, Edmond

22

Cermet fuel thermal conductivity  

E-Print Network [OSTI]

CERMET FUEL THERMAL CONDUCTIVITY A Thesis by JOHN MARK ALVIS, JR. Submitted to the Graduate College of Texas A&. M University in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Nuclear... particles of low conductivity dispersed in a metal matrix of high conductivity. A computer code was developed in order to compute the conductivity of cermet fuels as predicted by existing models and an additional model derived in this work...

Alvis, John Mark

1988-01-01T23:59:59.000Z

23

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

24

Journal of Power Sources 161 (2006) 11061115 Direct measurement of through-plane thermal conductivity and  

E-Print Network [OSTI]

conductivity and contact resistance in fuel cell materials Manish Khandelwal, M.M. Mench Fuel Cell Dynamics, and the thermal contact resistance between diffusion media and a metal plate as a function of temperature® membrane; Diffusion media; Thermal contact resistance 1. Introduction Detailed knowledge of the internal

Mench, Matthew M.

25

Low thermal conductivity skutterudites  

SciTech Connect (OSTI)

Recent experimental results on semiconductors with the skutterudite crystal structure show that these materials possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Both n-type and p-type conductivity samples have been obtained, using several preparation techniques. Associated with a low hole effective mass, very high carrier mobilities, low electrical resistivities and moderate Seebeck coefficients are obtained in p-type skutterudites. For a comparable doping level, the carrier mobilities of n-type samples are about an order of magnitude lower than the values achieved on p-type samples. However, the much larger electron effective masses and Seebeck coefficients on p-type samples. However, the much larger electron effective masses and Seebeck coefficients make n-type skutterudite promising candidates as well. Unfortunately, the thermal conductivities of the binary skutterudites compounds are too large, particularly at low temperatures, to be useful for thermoelectric applications. Several approaches to the reduction of the lattice thermal conductivity in skutterudites are being pursued: heavy doping, formation of solid solutions and alloys, study of novel ternary and filled skutterudite compounds. All those approaches have already resulted in skutterudite compositions with substantially lower thermal conductivity values in these materials. Recently, superior thermoelectric properties in the moderate to high temperature range were achieved for compositions combining alloying and filling of the skutterudite structure. Experimental results and mechanisms responsible for low thermal conductivity in skutterudites are discussed.

Fleurial, J.P.; Caillat, T.; Borshchevsky, A.

1997-07-01T23:59:59.000Z

26

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

SciTech Connect (OSTI)

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

Hurd, Joseph A.; Van Sciver, Steven W. [National High Magnetic Field Laboratory Tallahassee, FL 32310 USA and FAMU-FSU College of Engineering, Department of M.E., Tallahassee, FL 32310 (United States)

2014-01-29T23:59:59.000Z

27

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

28

Enhanced Thermal Conductivity Oxide Fuels  

SciTech Connect (OSTI)

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

Alvin Solomon; Shripad Revankar; J. Kevin McCoy

2006-01-17T23:59:59.000Z

29

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

SciTech Connect (OSTI)

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

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

2014-01-01T23:59:59.000Z

30

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

SciTech Connect (OSTI)

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

Nelson, Andrew T. [Los Alamos National Laboratory

2012-08-30T23:59:59.000Z

31

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

SciTech Connect (OSTI)

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

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

2014-05-01T23:59:59.000Z

32

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

33

An experimental measurement of the thermal conductivity and diffusivity of a porous solid-liquid system  

E-Print Network [OSTI]

to contain the sample for the flow rate measurement. 1. Air Supply 2 ~ Vacuun Line 3. Waste Line 4 ~ Surge Tank 5. Water Reservoir 6. Oil Reservoir Test Specinsn 8. Pressure Regulator Valve SATURATION APPARATUS FCR SATURATI?l SARDSTONR TXSP... the system can be described by' the one h dimensional form of Fouriers dT Equation: Q ~ -!:. A ? . ds The quantity of heat flowing through the oil and water in the pore dT space is OCk! ~ K A& ( ? ) + Kp AC (~)C ~ Based on the unidirectional W & d...

Dunn, James Elliott

1959-01-01T23:59:59.000Z

34

Continuous Processing of High Thermal Conductivity Polyethylene...  

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

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

35

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

36

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

37

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.

38

Experimental thermal conductivity and contact conductance of graphite composites  

E-Print Network [OSTI]

Figure 2. 1 One-Dimensional Heat Transfer by Conduction Across a Plane Wall Figure 2. 2 Fundamental Element for Electrically Based Thermal Model. . . 14 Figure 2. 3 Rectangular Unit Cell Orientation . 14 Figure 2. 4 Model of Parabolic Distribution... a low transverse thermal conductivity, they show better thermal performance than MMC's for some weight-critical applications (Ibrahim, 1992). Graphite/organic compound composites also will be reviewed. Using a high conductivity graphite fiber...

Jackson, Marian Christine

1998-01-01T23:59:59.000Z

39

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

40

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.

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

Experimental Measurement of the Interface Heat Conductance Between Nonconforming Beryllium and Type 316 Stainless Steel Surfaces Subjected to Nonuniform Thermal Deformations  

SciTech Connect (OSTI)

In fusion blanket designs that employ beryllium as a neutron multiplier, the interface conductance h plays a key role in evaluating the blanket's thermal profile. Therefore, an extensive experimental program was conducted to measure the magnitude of h between nonconforming beryllium and Type 316 stainless steel surfaces subjected to nonuniform thermal deformations. The magnitude of h was measured as a function of relevant environmental, surface, and geometric parameters, including surface roughness, contact pressure, gas pressure, gas type, and magnitude and direction of heat flow. The results indicate the following: (a) Decreasing the interfacial surface roughness from 6.28 to 0.28 {mu}m, in 760 Torr of helium, increased the magnitude of h by up to 100%; however, increasing the surface roughness reduced the dependence of h on the magnitude of the contact pressure. (b) The interface conductance was significantly higher for measurements made in helium gas as opposed to air. Additionally, the sensitivity of h to the gas pressure was significantly greater for runs conducted in helium and/or with smoother surfaces. This sensitivity was reduced in air and/or with roughened surfaces, and it was essentially nonexistent for the 6.25-{mu}m specimen for air pressures exceeding 76 Torr. (c) For runs conducted in vacuum, the interface conductance was more sensitive to heat flux than when runs were conducted in 760 Torr of helium. (d) The interface conductance was found to be dependent on the direction of heat flux. When the specimens were arranged so that heat flowed from the steel to the beryllium disk, the magnitude of h was generally greater than in the opposite direction.

Abelson, Robert Dean; Abdou, Mohamed A. [University of California, Los Angeles (United States)

2001-03-15T23:59:59.000Z

42

Thermal conductivity and heat transfer in superlattices  

SciTech Connect (OSTI)

Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and devices based on quantum structures. This work reports progress on the modeling of thermal conductivity of superlattice structures. Results from the models established based on the Boltzmann transport equation could explain existing experimental results on the thermal conductivity of semiconductor superlattices in both in plane and cross-plane directions. These results suggest the possibility of engineering the interfaces to further reduce thermal conductivity of superlattice structures.

Chen, G.; Neagu, M.; Borca-Tasciuc, T.

1997-07-01T23:59:59.000Z

43

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.

44

THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS  

SciTech Connect (OSTI)

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

ALLAN,M.

1998-05-01T23:59:59.000Z

45

An Innovative High Thermal Conductivity Fuel Design  

SciTech Connect (OSTI)

Thermal conductivity of the fuel in today's Light Water Reactors, Uranium dioxide, can be improved by incorporating a uniformly distributed heat conducting network of a higher conductivity material, Silicon Carbide. The higher thermal conductivity of SiC along with its other prominent reactor-grade properties makes it a potential material to address some of the related issues when used in UO2 [97% TD]. This ongoing research, in collaboration with the University of Florida, aims to investigate the feasibility and develop a formal methodology of producing the resultant composite oxide fuel. Calculations of effective thermal conductivity of the new fuel as a function of %SiC for certain percentages and as a function of temperature are presented as a preliminary approach. The effective thermal conductivities are obtained at different temperatures from 600K to 1600K. The corresponding polynomial equations for the temperature-dependent thermal conductivities are given based on the simulation results. Heat transfer mechanism in this fuel is explained using a finite volume approach and validated against existing empirical models. FLUENT 6.1.22 was used for thermal conductivity calculations and to estimate reduction in centerline temperatures achievable within such a fuel rod. Later, computer codes COMBINE-PC and VENTURE-PC were deployed to estimate the fuel enrichment required, to maintain the same burnup levels, corresponding to a volume percent addition of SiC.

Jamil A. Khan

2009-11-21T23:59:59.000Z

46

Electrical and thermal conductivities in dense plasmas  

SciTech Connect (OSTI)

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

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

2014-09-15T23:59:59.000Z

47

Thermal conductivity of bulk nanostructured lead telluride  

SciTech Connect (OSTI)

Thermal conductivity of lead telluride with embedded nanoinclusions was studied using Monte Carlo simulations with intrinsic phonon transport properties obtained from first-principles-based lattice dynamics. The nanoinclusion/matrix interfaces were set to completely reflect phonons to model the maximum interface-phonon-scattering scenario. The simulations with the geometrical cross section and volume fraction of the nanoinclusions matched to those of the experiment show that the experiment has already reached the theoretical limit of thermal conductivity. The frequency-dependent analysis further identifies that the thermal conductivity reduction is dominantly attributed to scattering of low frequency phonons and demonstrates mutual adaptability of nanostructuring and local disordering.

Hori, Takuma [Department of Mechanical Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8656 (Japan); Chen, Gang [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Shiomi, Junichiro, E-mail: shiomi@photon.t.u-tokyo.ac.jp [Department of Mechanical Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8656 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2014-01-13T23:59:59.000Z

48

Increased thermal conductivity monolithic zeolite structures  

DOE Patents [OSTI]

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

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

2008-11-25T23:59:59.000Z

49

Fabrication and Characterization of a Conduction Cooled Thermal Neutron Filter  

SciTech Connect (OSTI)

Installation of a conduction cooled thermal (low-energy) neutron filter in an existing domestic test reactor would provide the U.S. the capability to test new reactor fuels and materials for advanced fast (high-energy) reactor concepts. A composite consisting of Al3Hf-Al has been proposed for the neutron filter due to both the neutron filtering properties of hafnium and the conducting capabilities of aluminum. Knowledge of the thermal conductivity of the Al3Hf-Al composite is essential for the design of the filtering system. The present objectives are to identify a suitable fabrication technique and to measure the thermophysical properties of the Al3Hf intermetallic, which has not been done previous to this study. A centrifugal casting method was used to prepare samples of Al3Hf. X-ray diffraction and Rietveld analysis were conducted to determine the structural make-up of each of the samples. Thermophysical properties were measured as follows: specific heat by a differential scanning calorimeter (DSC), thermal diffusivity by a laser flash thermal diffusivity measuring system, thermal expansion by a dilatometer, and thermal conductivity was calculated based on the previous measurements. All measurements were acquired over a temperature range of 90°C - 375°C with some measurements outside these bounds. The average thermal conductivity of the intermetallic Al3Hf (~7 at.% Hf) was found to be ~ 41 W/m-K for the given temperature range. This information fills a knowledge gap in the thermophysical properties of the intermetallic Al3Hf with the specified percentage of hafnium. A model designed to predict composite properties was used to calculate a thermal conductivity of ~177 W/m-K for an Al3Hf-Al composite with 23 vol% Al3Hf. This calculation was based upon the average thermal conductivity of Al3Hf over the specified temperature range.

Heather Wampler; Adam Gerth; Heng Ban; Donna Post Guillen; Douglas Porter; Cynthia Papesch

2010-06-01T23:59:59.000Z

50

Thermal Conductivity in Nanocrystalline Ceria Thin Films  

SciTech Connect (OSTI)

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

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

2014-02-01T23:59:59.000Z

51

An International Round-Robin Study, Part II: Thermal Diffusivity, Specific Heat and Thermal Conductivity  

SciTech Connect (OSTI)

For bulk thermoelectrics, figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In recent years, the most significant improvements in ZT were mainly due to successful reduction of thermal conductivity. However, thermal conductivity cannot be measured directly at high temperatures. The combined measurements of thermal diffusivity and specific heat and density are required. It has been shown that thermal conductivity is the property with the greatest uncertainty and has a direct influence on the accuracy of the figure of merit. The International Energy Agency (IEA) group under the implementing agreement for Advanced Materials for Transportation (AMT) has conducted two international round-robins since 2009. This paper is Part II of the international round-robin testing of transport properties of bulk bismuth telluride. The main focuses in Part II are on thermal diffusivity, specific heat and thermal conductivity.

Wang, Hsin [ORNL; Porter, Wallace D [ORNL; Bottner, Harold [Fraunhofer-Institute, Freiburg, Germany; Konig, Jan [Fraunhofer-Institute, Freiburg, Germany; Chen, Lidong [Chinese Academy of Sciences; Bai, Shengqiang [Chinese Academy of Sciences; Tritt, Terry M. [Clemson University; Mayolett, Alex [Corning, Inc; Senawiratne, Jayantha [Corning, Inc; Smith, Charlene [Corning, Inc; Harris, Fred [ZT-Plus; Gilbert, Partricia [Marlow Industries, Inc; Sharp, J [Marlow Industries, Inc; Lo, Jason [CANMET - Materials Technology Laboratory, Natural Resources of Canada; Keinke, Holger [University of Waterloo, Canada; Kiss, Laszlo I. [University of Quebec at Chicoutimi

2013-01-01T23:59:59.000Z

52

Gas storage carbon with enhanced thermal conductivity  

DOE Patents [OSTI]

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

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

2000-01-01T23:59:59.000Z

53

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

54

Continuous Processing of High Thermal Conductivity Fibers and...  

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

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

55

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

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

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

56

Metallic coatings for enhancement of thermal contact conductance  

SciTech Connect (OSTI)

The reliability of standard electronic modules may be improved by decreasing overall module temperature. This may be accomplished by enhancing the thermal contact conductance at the interface between the module frame guide rib and the card rail to which the module is clamped. Some metallic coatings, when applied to the card rail, would deform under load, increasing the contact area and associated conductance. This investigation evaluates the enhancements in thermal conductance afforded by vapor deposited silver and gold coatings. Experimental thermal conductance measurements were made for anodized aluminum 6101-T6 and electroless nickel-plated copper C11000-H03 card materials to the aluminum A356-T61 rail material. Conductance values for the electroless nickel-plated copper junction ranged from 600 to 2800 W/m(exp 2)K and those for the anodized aluminum junction ranged from 25 to 91 W/m(exp 2)K for contact pressures of 0.172-0.862 MPa and mean junction temperatures of 20-100 C. Experimental thermal conductance values of vapor deposited silver- and gold-coated aluminum A356-T61 rail surfaces indicate thermal enhancements of 1.25-2.19 for the electroless nickel-plated copper junctions and 1.79-3.41 for the anodized aluminum junctions. The silver and gold coatings provide significant thermal enhancement; however, these coating-substrate combinations are susceptible to galvanic corrosion under some conditions. 25 refs.

Lambert, M.A.; Fletcher, L.S. (Texas A M Univ., College Station, TX (United States))

1994-04-01T23:59:59.000Z

57

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.

58

THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS  

SciTech Connect (OSTI)

This model report addresses activities described in ''Technical Work Plan for: Near-Field Environment and Transport Thermal Properties and Analysis Reports Integration'' (BSC 2004 [DIRS 171708]). The model develops values for thermal conductivity, and its uncertainty, for the nonrepository layers of Yucca Mountain; in addition, the model provides estimates for matrix porosity and dry bulk density for the nonrepository layers. The studied lithostratigraphic units, as identified in the ''Geologic Framework Model'' (GFM 2000) (BSC 2004 [DIRS 170029]), are the Timber Mountain Group, the Tiva Canyon Tuff, the Yucca Mountain Tuff, the Pah Canyon Tuff, the Topopah Spring Tuff (excluding the repository layers), the Calico Hills Formation, the Prow Pass Tuff, the Bullfrog Tuff, and the Tram Tuff. The deepest model units of the GFM (Tund and Paleozoic) are excluded from this study because no data suitable for model input are available. The parameter estimates developed in this report are used as input to various models and calculations that simulate heat transport through the rock mass. Specifically, analysis model reports that use product output from this report are: (1) Drift-scale coupled processes (DST and TH seepage) models; (2) Drift degradation analysis; (3) Multiscale thermohydrologic model; and (4) Ventilation model and analysis report. In keeping with the methodology of the thermal conductivity model for the repository layers in ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]), the Hsu et al. (1995 [DIRS 158073]) three-dimensional (3-D) cubic model (referred to herein as ''the Hsu model'') was used to represent the matrix thermal conductivity as a function of the four parameters (matrix porosity, thermal conductivity of the saturating fluid, thermal conductivity of the solid, and geometric connectivity of the solid). The Hsu model requires input data from each test specimen to meet three specific conditions: (1) Known value for matrix porosity; (2) Known values for wet and dry thermal conductivity; and (3) The location of the measured specimen in relation to the model stratigraphic unit. The only matrix thermal conductivity values developed are limited to fully saturated and dry conditions. The model does not include the effects of convection and thermal radiation in voids. The model does not include temperature dependence of thermal conductivity, porosity, or bulk density.

R. JONES

2004-10-22T23:59:59.000Z

59

Thermal conduction of SSC (Superconducting Super Collider) wire  

SciTech Connect (OSTI)

A method suitable for measuring the thermal conductivity of good thermal conductors at low temperatures was implemented. It successfully served its purpose: to detect the effect of doping with manganese the interfilament part of the copper matrix of the superconducting wire used in the magnets of the Superconducting Super Collider. It uses two heaters and one thermometer per sample reducing the accuracy requirement on the thermometers, automatically compensating for zero offsets and reducing the number of critical thermal contacts. Commercially available strain gauges are used as heaters. 3 refs., 2 figs.

Kuchnir, M.; Tague, J.L.

1989-08-01T23:59:59.000Z

60

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

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

Hydraulic Conductivity Measurements Barrow 2014  

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

Six individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, in May of 2013 as part of the Next Generation Ecosystem Experiment (NGEE). Each core was drilled from a different location at varying depths. A few days after drilling, the cores were stored in coolers packed with dry ice and flown to Lawrence Berkeley National Laboratory (LBNL) in Berkeley, CA. 3-dimensional images of the cores were constructed using a medical X-ray computed tomography (CT) scanner at 120kV. Hydraulic conductivity samples were extracted from these cores at LBNL Richmond Field Station in Richmond, CA, in February 2014 by cutting 5 to 8 inch segments using a chop saw. Samples were packed individually and stored at freezing temperatures to minimize any changes in structure or loss of ice content prior to analysis. Hydraulic conductivity was determined through falling head tests using a permeameter [ELE International, Model #: K-770B]. After approximately 12 hours of thaw, initial falling head tests were performed. Two to four measurements were collected on each sample and collection stopped when the applied head load exceeded 25% change from the original load. Analyses were performed between 2 to 3 times for each sample. The final hydraulic conductivity calculations were computed using methodology of Das et al., 1985.

Katie McKnight; Tim Kneafsey; Craig Ulrich; Jil Geller

62

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

63

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

64

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

65

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.

66

THERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND  

E-Print Network [OSTI]

envelope and on the performance of systems. This behaviour is related to hygric and thermal propertiesTHERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND WATER CONTENT of formulation, density and water content on the thermal conductivity of hemp concretes. The investigations

67

Thermal conductivity of electroless nickel-phosphorus alloy plating  

SciTech Connect (OSTI)

Properties of specific heat, thermal diffusivity, density, and calculated thermal conductivity have been determined for a modified acid bath electroless nickel-12.7 wt% phosphorus alloy between 298 ad 423 K. Thermal conductivity values are about half those of pure nickel.

Smith, D.D.

1982-04-01T23:59:59.000Z

68

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

69

Report on workshop on thermal property measurements  

SciTech Connect (OSTI)

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

Robertson, E.C.

1987-01-01T23:59:59.000Z

70

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network [OSTI]

Brown, C. M. ; Zhang, Q. ; Tritt, T. M. Nano Letters 2010,Monteiro, O. Microelectronics journal Tritt, T. M. , Thermal

Wang, Zhaojie

2012-01-01T23:59:59.000Z

71

Thermal conductivity of graphene nanoribbons in noble gaseous environments  

SciTech Connect (OSTI)

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

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

2014-02-24T23:59:59.000Z

72

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

E-Print Network [OSTI]

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

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

2006-01-01T23:59:59.000Z

73

Electrical and thermal conductivity of low temperature CVD graphene...  

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

and thermal conductivity of low temperature CVD graphene: the effect of disorder This article has been downloaded from IOPscience. Please scroll down to see the full text article....

74

New equation calculates thermal conductivities of C[sub 1]-C[sub 4] gases  

SciTech Connect (OSTI)

In the design of heat exchangers, heat-transfer coefficients are commonly calculated for individual items. These calculations require knowledge of the thermal conductivities of the species involved. The calculation require knowledge of the thermal conductivities of the species involved. The calculation of the overall heat-transfer coefficient for a heat exchanger also requires thermal conductivity data for the individual species. In fact, thermal conductivity is the fundamental property involved in heat transfer. Ordinarily, thermal conductivities are either measured experimentally or estimated using complex correlations and models. Engineers must search existing literature for the values needed. Here, a compilation of thermal conductivity data for gases is presented for a wide temperature range. Using these data with the accompanying equation will enable engineers to quickly determine values at the desired temperatures. The results are provided in an easy-to-use tabular format, which is especially helpful for rapid calculations using a personal computer or hand-held calculator.

Yaws, C.L.; Lin, X.; Bu, L.; Nijhawan, S. (Lamar Univ., Beaumont, TX (United States))

1994-04-18T23:59:59.000Z

75

MOLECULAR DYNAMICS SIMULATION OF THERMAL BOUNDARY CONDUCTANCE BETWEEN SWNT AND  

E-Print Network [OSTI]

MOLECULAR DYNAMICS SIMULATION OF THERMAL BOUNDARY CONDUCTANCE BETWEEN SWNT AND SURROUNDING FLUIDS JinHyeok Cha, Shohei Chiashi, Junichiro Shiomi, and Shigeo Maruyama* Department of Mechanical applications. In particular, the thermal boundary conductance (TBC) K between an SWNT and surrounding fluid

Maruyama, Shigeo

76

Effect of Aggregation on Thermal Conduction in Colloidal Nanofluids  

SciTech Connect (OSTI)

Using effective medium theory we demonstrate that the thermal conductivity of nanofluids can be significantly enhanced by the aggregation of nanoparticles into clusters. The enhancement is based purely on conduction and does not require a novel mechanism. Predictions of the effective medium theory are in excellent agreement with detailed numerical calculations on model nanofluids involving fractal clusters and show the importance of cluster morphology on thermal conductivity enhancements.

R Prasher; W Evans; J Fish; P Meakin; P Phelan; Pawel Keblinski

2006-08-10T23:59:59.000Z

77

Thermal conductivity of beryllium-gas packed bed  

SciTech Connect (OSTI)

Unsintered packed bed has been suggested as a material form for solid breeder and multiplier in the ITER and fusion power reactor blankets. Study of the effective bed thermal conductivity can provide tools for analysis of the blanket performance under different operating conditions, and of how to actively control the thermal behavior of the blanket. Issues of particular interest are the ability to predict and to control the thermal conductivity. The 2-D model developed at UCLA is used to study the effect of particle diameter, solid-to-gas conductivity ratio, bed porosity, contact area, and surface roughness characteristics on bed thermal conductivity. The study shows that all parameters except bed porosity play important roles in determining the bed thermal controllability.

Xu, M.; Abdou, M.A.; Raffray, A.R. [Univ. of California, Los Angeles, CA (United States)

1994-12-31T23:59:59.000Z

78

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

SciTech Connect (OSTI)

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

Nguyen, Ba Nghiep; Henager, Charles H.

2013-04-20T23:59:59.000Z

79

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

80

Odne Stokke Burheim Thermal Signature and Thermal Conductivities of PEM Fuel Cells  

E-Print Network [OSTI]

Odne Stokke Burheim Thermal Signature and Thermal Conductivities of PEM Fuel Cells Thesis-Holst for believing in me and for giving me the opportunity to join the work on the "Thermal Effects in Fuel cell The work presented here gives estimates on thermal gradients within the PEM fuel cell, an experimental

Kjelstrup, Signe

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

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

Open Energy Info (EERE)

Study Of A 2-Layer Transient Thermal Conduction Problem As Applied To Soil-Temperature Surveys Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...

82

Experimental investigations of solid-solid thermal interface conductance  

E-Print Network [OSTI]

Understanding thermal interface conductance is important for nanoscale systems where interfaces can play a critical role in heat transport. In this thesis, pump and probe transient thermoreflectance methods are used to ...

Collins, Kimberlee C. (Kimberlee Chiyoko)

2010-01-01T23:59:59.000Z

83

A benchmark study on the thermal conductivity of nanofluids  

E-Print Network [OSTI]

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was ...

Buongiorno, Jacopo

84

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

85

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

86

The thermal conductivity of sediments as a function of porosity  

E-Print Network [OSTI]

1979 Major Subject: Civil Engineering THE THERMAL CONDUCTIVITY OF SEDIMENTS AS A FUNCTION OF POROSITY A Thesis by JAMES WARREN MILLER Approved as to style and content by: Louis J. hompson CE)(Chairman of Committee) Harry M. Coyle (CE)( ember...THE THERMAL CONDUCTIVITY OF SEDIMENTS AS A FUNCTION OF POROSITY A Thesis by JAMES WARREN MILLER Submitted to the Graduate College of Texas AAM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August...

Miller, James W

1979-01-01T23:59:59.000Z

87

Modeling the thermal conductivity of fiber-reinforced ceramic composites  

SciTech Connect (OSTI)

A review of models for the prediction of the thermal conductivity of uni-directional fiber-reinforced composites will be presented. The ability of these models to give an accurate prediction of the composite thermal conductivity depends on the amount of information known about the constituent phase properties under the assumption that these properties do not change as a result of processing. Also presented are models that take into account the effects of fiber coatings.

Beecher, S.C.; Dinwiddie, R.B.

1993-06-01T23:59:59.000Z

88

Thermal conductivity profile determination in proton-irradiated ZrC by spatial and frequency scanning thermal wave methods  

SciTech Connect (OSTI)

Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ?52 ± 2 ?m deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m{sup ?1} K{sup ?1} and 26.7 ±1 W m{sup ?1} K{sup ?1}, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10{sup ?6} m{sup 2} K W{sup ?1}. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials.

Jensen, C. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France) [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States); Chirtoc, M.; Horny, N.; Antoniow, J. S.; Pron, H. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France)] [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Ban, H. [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)] [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)

2013-10-07T23:59:59.000Z

89

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

90

Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites  

SciTech Connect (OSTI)

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

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

2014-01-01T23:59:59.000Z

91

Lattice thermal conductivity of nanograined half-Heusler solid solutions  

SciTech Connect (OSTI)

We report a phenomenological model of atomic weight, lattice constant, temperature, and grain size to calculate the high-temperature lattice thermal conductivity of nanograined solid solutions. The theoretical treatment developed here is reasonably consistent with the experimental results of n-type MNiSn and p-type MCoSb alloys, where M is the combination of Hf, Zr, and Ti. For disordered half-Heusler alloys with moderated grain sizes, we predict that the reduction in lattice thermal conductivity due to grain boundary scattering is independent of the scattering parameter, which characterizes the phonon scattering cross section of point defects. In addition, the lattice thermal conductivity falls off with temperature as T{sup –1?2} around the Debye temperature.

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

2014-05-19T23:59:59.000Z

92

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

93

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

94

High thermal conductivity lossy dielectric using a multi layer configuration  

DOE Patents [OSTI]

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

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

2003-01-01T23:59:59.000Z

95

Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives  

SciTech Connect (OSTI)

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

Ronald baney; James Tulenko

2012-11-20T23:59:59.000Z

96

Basal-plane thermal conductivity of few-layer molybdenum disulfide  

SciTech Connect (OSTI)

We report the in-plane thermal conductivity of suspended exfoliated few-layer molybdenum disulfide (MoS{sub 2}) samples that were measured by suspended micro-devices with integrated resistance thermometers. The obtained room-temperature thermal conductivity values are (44–50) and (48–52) W m{sup ?1} K{sup ?1} for two samples that are 4 and 7 layers thick, respectively. For both samples, the peak thermal conductivity occurs at a temperature close to 120?K, above which the thermal conductivity is dominated by intrinsic phonon-phonon scattering although phonon scattering by surface disorders can still play an important role in these samples especially at low temperatures.

Jo, Insun; Ou, Eric; Shi, Li, E-mail: lishi@mail.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Pettes, Michael Thompson [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering and the Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Wu, Wei [Department of Mechanical Engineering and the Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)

2014-05-19T23:59:59.000Z

97

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

98

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

99

Mode dependent lattice thermal conductivity of single layer graphene  

SciTech Connect (OSTI)

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

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

2014-10-21T23:59:59.000Z

100

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

2007-03-20T23:59:59.000Z

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.


101

Thermal Crosslinking of Organic Semiconducting Polythiophene Improves Transverse Hole Conductivity  

SciTech Connect (OSTI)

Thermal crosslinking using a suitable radical initiator simultaneously improves electrical conductivity in the semiconducting polymer poly(3-hexylthiophene) and makes the material insoluble. Crosslinked polythiophene shows as much as a fivefold increase in hole conductivity across the film thickness without any shift in spectral light absorption. Grazing incidence x-ray diffraction reveals more in-plane polymer lamellae stacking with only a small decrease in film crystallinity. Improved transverse conductivity increases the performance of model planar solar cells by threefold, from 0.07% to 0.2%. The ability to render polythiophene insoluble without disrupting film structural order enables fabrication pathways to more complex device architectures.

Gearba, I.R.; Nam, C.-Y.; Pindak, R.; Black, C.T.

2009-10-26T23:59:59.000Z

102

Effect of interfacial interactions on the thermal conductivity and interfacial thermal conductance in tungsten–graphene layered structure  

SciTech Connect (OSTI)

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

Jagannadham, K., E-mail: jag-kasichainula@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-09-01T23:59:59.000Z

103

Effective thermal conductivity for anisotropic granular porous media using fractal concepts  

SciTech Connect (OSTI)

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

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

1997-07-01T23:59:59.000Z

104

Effects of neutron irradiation on thermal conductivity of SiC-based composites and monolithic ceramics  

SciTech Connect (OSTI)

A variety of SiC-based composites and monolithic ceramics were characterized by measuring their thermal diffusivity in the unirradiated, thermal annealed, and irradiated conditions over the temperature range 400 to 1,000 C. The irradiation was conducted in the EBR-II to doses of 33 and 43 dpa-SiC (185 EFPD) at a nominal temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. Thermal diffusivity was measured using the laser flash method, and was converted to thermal conductivity using density data and calculated specific heat values. Exposure to the 165 day anneal did not appreciably degrade the conductivity of the monolithic or particulate-reinforced composites, but the conductivity of the fiber-reinforced composites was slightly degraded. The crystalline SiC-based materials tested in this study exhibited thermal conductivity degradation of irradiation, presumably caused by the presence of irradiation-induced defects. Irradiation-induced conductivity degradation was greater at lower temperatures, and was typically more pronounced for materials with higher unirradiated conductivity. Annealing the irradiated specimens for one hour at 150 C above the irradiation temperature produced an increase in thermal conductivity, which is likely the result of interstitial-vacancy pair recombination. Multiple post-irradiation anneals on CVD {beta}-SiC indicated that a portion of the irradiation-induced damage was permanent. A possible explanation for this phenomenon was the formation of stable dislocation loops at the high irradiation temperature and/or high dose that prevented subsequent interstitial/vacancy recombination.

Senor, D.J.; Youngblood, G.E. [Pacific Northwest National Lab., Richland, WA (United States); Moore, C.E. [Auburn Univ., AL (United States); Trimble, D.J. [Westinghouse Hanford Co., Richland, WA (United States); Woods, J.J. [Lockheed Martin, Schenectady, NY (United States)

1996-06-01T23:59:59.000Z

105

Effects of neutron irradiation on thermal conductivity of SiC-based composites and monolithic ceramics  

SciTech Connect (OSTI)

A variety of SiC-based composites and monolithic ceramics were characterized by measuring their thermal diffusivity in the unirradiated, thermal annealed, and irradiated conditions over the temperature range 400 to 1,000 C. The irradiation was conducted in the EBR-II to doses of 33 and 43 dpa-SiC (185 EFPD) at a nominal temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. Thermal diffusivity was measured using the laser flash method, and was converted to thermal conductivity using density data and calculated specific heat values. Exposure to the 165 day anneal did not appreciably degrade the conductivity of the monolithic or particulate-reinforced composites, but the conductivity of the fiber-reinforced composites was slightly degraded. The crystalline SiC-based materials tested in this study exhibited thermal conductivity degradation after irradiation, presumably caused by the presence of irradiation-induced defects. Irradiation-induced conductivity degradation was greater at lower temperatures, and was typically more pronounced for materials with higher unirradiated conductivity. Annealing the irradiated specimens for one hour at 150 C above the irradiation temperature produced an increase in thermal conductivity, which is likely the result of interstitial-vacancy pair recombination. Multiple post-irradiation anneals on CVD {beta}-SiC indicated that a portion of the irradiation-induced damage was permanent. A possible explanation for this phenomenon was the formation of stable dislocation loops at the high irradiation temperature and/or high dose that prevented subsequent interstitial/vacancy recombination.

Senor, D.J.; Youngblood, G.E. [Pacific Northwest National Lab., Richland, WA (United States); Moore, C.E. [Auburn Univ., AL (United States); Trimble, D.J. [Westinghouse Hanford Co., Richland, WA (United States); Woods, J.J. [Lockheed Martin, Schenectady, NY (United States)

1997-05-01T23:59:59.000Z

106

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

E-Print Network [OSTI]

Determination of Thermal Diffusivities, Thermal Conductivities, and Sound Speeds of Room. The experiments give thermal diffusivities from which thermal conductivities can be determined, sound speeds not only on the sound speed but also on the thermal diffusivity and acoustic damping of the RTILs

Reid, Scott A.

107

Measurements of thermal accommodation coefficients.  

SciTech Connect (OSTI)

A previously-developed experimental facility has been used to determine gas-surface thermal accommodation coefficients from the pressure dependence of the heat flux between parallel plates of similar material but different surface finish. Heat flux between the plates is inferred from measurements of temperature drop between the plate surface and an adjacent temperature-controlled water bath. Thermal accommodation measurements were determined from the pressure dependence of the heat flux for a fixed plate separation. Measurements of argon and nitrogen in contact with standard machined (lathed) or polished 304 stainless steel plates are indistinguishable within experimental uncertainty. Thus, the accommodation coefficient of 304 stainless steel with nitrogen and argon is estimated to be 0.80 {+-} 0.02 and 0.87 {+-} 0.02, respectively, independent of the surface roughness within the range likely to be encountered in engineering practice. Measurements of the accommodation of helium showed a slight variation with 304 stainless steel surface roughness: 0.36 {+-} 0.02 for a standard machine finish and 0.40 {+-} 0.02 for a polished finish. Planned tests with carbon-nanotube-coated plates will be performed when 304 stainless-steel blanks have been successfully coated.

Rader, Daniel John; Castaneda, Jaime N.; Torczynski, John Robert; Grasser, Thomas W.; Trott, Wayne Merle

2005-10-01T23:59:59.000Z

108

Effective Thermal Conductivity of Lithium Ceramic Pebble Beds for Fusion Blankets: A Review  

SciTech Connect (OSTI)

The use of lithium ceramic pebble beds has been considered in many blanket designs for the fusion reactors. Lithium ceramics have received a significant interest as tritium breeders for the fusion blankets during the last three decades. The thermal performance of the lithium ceramic pebble beds plays a key role for the fusion blankets. In order to study the heat transfer in the blanket, the effective thermal conductivity of the lithium ceramics pebble beds has to be well measured and characterized. The data of effective thermal conductivity of lithium ceramic pebble beds is important for the blanket design. Several studies have been dedicated to investigate the effective conductivity of the lithium ceramics pebble beds. The objective of this work is to review and compare the available data, presented by various studies, of effective conductivity of lithium ceramic pebble beds in order to address the current status of these data.

Abou-Sena, A.; Ying, A.; Abdou, M. [University of California, Los Angeles (United States)

2005-05-15T23:59:59.000Z

109

Lattice thermal conductivity of filled skutterudites: An anharmonicity perspective  

SciTech Connect (OSTI)

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

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

2014-10-28T23:59:59.000Z

110

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

E-Print Network [OSTI]

both the United States Department of Energy and Texas Advanced Research Program. vi NOMENCLATURE D Thermal diffusivity Ei Exponential integral k Thermal conductivity k n Nanofluid thermal conductivity k b Base fluid thermal...?s thermal conductivity (k) and thermal diffusivity (D), are related to the temperature difference null?nullnull between the heat source and surrounding medium at a distance (r) from the source of a quantity of heat (Q) a certain time (t) after the heat...

Fortenberry, Stephen

2009-09-30T23:59:59.000Z

111

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

112

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

113

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

114

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

SciTech Connect (OSTI)

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

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

2012-05-15T23:59:59.000Z

115

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

116

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

117

Enhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid  

E-Print Network [OSTI]

by their very low thermal conductivity. These fluids have almost two orders of magnitude lower thermal, a significant amount of data has been gathered on the thermal conductivity of nanofluids. Typical materials usedEnhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid J

118

E-Print Network 3.0 - apparent thermal conductivity Sample Search...  

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

293 K. To obtain data... results 4,5. Comparing to the apparent thermal conductivity of aerogel when the boundary temperatures... THERMAL ... Source: Chang, Ho-Myung - Department...

119

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

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

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

120

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.

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

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.

122

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

123

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

SciTech Connect (OSTI)

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

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

2006-06-26T23:59:59.000Z

124

Thermal conductivity of ultra-thin chemical vapor deposited hexagonal boron nitride films  

SciTech Connect (OSTI)

Thermal conductivity of freestanding 10?nm and 20?nm thick chemical vapor deposited hexagonal boron nitride films was measured using both steady state and transient techniques. The measured value for both thicknesses, about 100?±?10?W m{sup ?1} K{sup ?1}, is lower than the bulk basal plane value (390?W m{sup ?1} K{sup ?1}) due to the imperfections in the specimen microstructure. Impressively, this value is still 100 times higher than conventional dielectrics. Considering scalability and ease of integration, hexagonal boron nitride grown over large area is an excellent candidate for thermal management in two dimensional materials-based nanoelectronics.

Alam, M. T.; Haque, M. A., E-mail: mah37@psu.edu [Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Bresnehan, M. S.; Robinson, J. A. [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2014-01-06T23:59:59.000Z

125

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

126

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

127

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

128

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

129

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.

130

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

SciTech Connect (OSTI)

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

Gorham, Caroline S.; Gaskins, John T.; Hopkins, Patrick E., E-mail: phopkins@virginia.edu [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Parsons, Gregory N.; Losego, Mark D. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-06-23T23:59:59.000Z

131

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

SciTech Connect (OSTI)

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

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

2013-12-04T23:59:59.000Z

132

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

E-Print Network [OSTI]

-TO-GAS THERMAL CONDUCTIVITY RATIO A.R. Raffray, Z. Gorbis, A. Badawi, M.S. Tillack, A.Y. Ying, and M. A. Abdou

Abdou, Mohamed

133

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

134

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

135

Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction  

SciTech Connect (OSTI)

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

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

2014-02-24T23:59:59.000Z

136

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

137

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

138

Development of a Test Technique to Determine the Thermal Conductivity of Large Refractory Ceramic Test Specimens  

SciTech Connect (OSTI)

A method has been developed to utilize the High Intensity Infrared lamp located at Oak Ridge National Laboratory for the measurement of thermal conductivity of bulk refractory materials at elevated temperatures. The applicability of standardized test methods to determine the thermal conductivity of refractory materials at elevated temperatures is limited to small sample sizes (laser flash) or older test methods (hot wire, guarded hot plate), which have their own inherent problems. A new method, based on the principle of the laser flash method, but capable of evaluating test specimens on the order of 200 x 250 x 50 mm has been developed. Tests have been performed to validate the method and preliminary results are presented in this paper.

Hemrick, James Gordon [ORNL; Dinwiddie, Ralph Barton [ORNL; Loveland, Erick R [ORNL; Prigmore, Andre L [ORNL

2012-01-01T23:59:59.000Z

139

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.

140

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

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

Fractal-like tree networks reducing the thermal conductivity Boming Yu1,  

E-Print Network [OSTI]

Fractal-like tree networks reducing the thermal conductivity Boming Yu1, * and Baowen Li1,2 1 conductivity of composites with embedded self-similar H-shaped fractal-like tree networks is studied that the thermal conductivity of the H-shaped fractal-like tree networks does not obey Murray's law. The present

Li, Baowen

142

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

143

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

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

1992-01-01T23:59:59.000Z

144

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

145

Size dependent thermal conductivity of single-walled carbon nanotubes Ajing Cao and Jianmin Qu  

E-Print Network [OSTI]

. Phys. Lett. 100, 261908 (2012) Focus shift photothermal method for thermal diffusivity mapping J. Appl Institute of Physics. Related Articles Enhanced high thermal conductivity and low permittivity of polyimide

Chen, Wei

146

Reversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions  

E-Print Network [OSTI]

Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce ...

Zheng, Ruiting

147

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

148

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

149

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

SciTech Connect (OSTI)

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

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

2013-10-15T23:59:59.000Z

150

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

151

Enhanced Thermal Conductivity of Water with Surfactant Encapsulated and Individualized Single-Walled Carbon Nanotube Dispersions  

E-Print Network [OSTI]

.L, Review of heat conduction in nanofluids, Journal of Heat transfer, 2011, 133, pp 040801-1-040801-14. #12; layering were considered to be responsible for the thermal conductivity enhancement in the open literature

Maruyama, Shigeo

152

High sensitivity measurements of thermal properties of textile fabrics  

E-Print Network [OSTI]

A new testing apparatus is proposed to measure the thermal properties of fabrics made from polymeric materials. The calibration of the apparatus and the data acquisition procedure are considered in detail in order to measure thermal conductivity, resistance, absorption and diffusivity constants of the tested fabric samples. Differences between dry and wet fabrics have been carefully detected and analyzed. We have developed a new measurement protocol, the "ThermoTex" protocol, which agrees with the UNI EN 31092 standard and entails an accurate quantification of the experimental errors according to a standard statistical analysis, thus allowing a rigorous investigation of the physical behavior of the phenomena involved. As a consequence, our machinery exhibits great potentialities for optimizing the thermal comfort of fabrics, according to the market demand, thanks to the possible development of a predictive phenomenological theory of the effects involved.

Romeli, D; Esposito, S; Rosace, G; Salesi, G

2013-01-01T23:59:59.000Z

153

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

SciTech Connect (OSTI)

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

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

1985-11-01T23:59:59.000Z

154

Computational analysis of the thermal conductivity of the carboncarbon composite materials  

E-Print Network [OSTI]

Computational analysis of the thermal conductivity of the carbon­carbon composite materials M Abstract Experimental data for carbon­carbon con- stituent materials are combined with a three and longitudinal thermal conductivities in carbon­carbon composites. Particular attention is given in elucidating

Grujicic, Mica

155

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

E-Print Network [OSTI]

, polycrystalline diamond PCD , diamondlike carbon DLC , carbon nanotubes, and single-layer graphene, have recentlyThermal conductivity of nitrogenated ultrananocrystalline diamond films on silicon M. Shamsa,1,a S of nitrogenated ultrananocrystalline diamond UNCD films on silicon. For better accuracy, the thermal conductivity

156

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

157

Sound Waves, Thermal Conduction, and the Continuity Equation Carl Sovinec, T-15 LANL  

E-Print Network [OSTI]

Sound Waves, Thermal Conduction, and the Continuity Equation Carl Sovinec, T-15 LANL 8 to sound waves when we use thermal conduction in our system of equations without continuity. The fluid definitions 0 02 p c , defining c as the adiabatic sound speed, kc 1 , the time for the adiabatic wave

Sovinec, Carl

158

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.

159

Study of thermal conductivity in organic solid wastes before composting J. HUET, C. Druilhe, G. Debenest  

E-Print Network [OSTI]

Study of thermal conductivity in organic solid wastes before composting J. HUET, C. Druilhe, G. Debenest ORBIT2012 1 STUDY OF THERMAL CONDUCTIVITY IN ORGANIC SOLID WASTES BEFORE COMPOSTING J. Huet, as illustrated by current EU waste policy and its five main priorities: prevention, reuse, recycling, recovery

Paris-Sud XI, Université de

160

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.

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.


161

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

162

Discrete thermal element modelling of heat conduction in particle systems: Basic formulations  

E-Print Network [OSTI]

methodology, termed the discrete thermal element method (DTEM), for the effec- tive modelling of heat rights reserved. Keywords: Discrete thermal element method; Circular particle; Thermal contact; Heat conduction; Boundary (integral) equation/element 1. Introduction Heat transfer in particle systems can

Martin, Ralph R.

163

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

SciTech Connect (OSTI)

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

Secary, J.J.

1989-01-01T23:59:59.000Z

164

Thermal conductivity of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} solid solutions  

SciTech Connect (OSTI)

{beta}-Zn{sub 4}Sb{sub 3} was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy {beta}-Zn{sub 4}Sb{sub 3} with isostructural compounds because of the expected decrease in lattice thermal conductivity. The authors have grown Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} crystals with 0.2 {le} x < 1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} alloys are significantly lower than those measured for {beta}-Zn{sub 4}Sb{sub 3} and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

Caillat, T.; Borshchevsky, A.; Fleurial, J.P.

1997-07-01T23:59:59.000Z

165

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

SciTech Connect (OSTI)

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

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

2014-04-28T23:59:59.000Z

166

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

SciTech Connect (OSTI)

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

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

2014-01-07T23:59:59.000Z

167

The Role of Thermal Conduction in Tearing Mode Theory  

E-Print Network [OSTI]

The role of anisotropic thermal diffusivity on tearing mode stability is analysed in general toroidal geometry. A dispersion relation linking the growth rate to the tearing mode stability parameter, Delta, is derived. By using a resistive MHD code, modified to include such thermal transport, to calculate tearing mode growth rates, the dispersion relation is employed to determine Delta in situations with finite plasma pressure that are stabilised by favourable average curvature in a simple resistive MHD model. We also demonstrate that the same code can also be used to calculate the basis-functions [C J Ham, et al, Plasma Phys. Control. Fusion 54 (2012) 105014] needed to construct Delta.

Connor, J W; Hastie, R J; Liu, Y Q

2014-01-01T23:59:59.000Z

168

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

SciTech Connect (OSTI)

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

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

2014-08-28T23:59:59.000Z

169

Effective Thermal Conductivity of a Li{sub 2}TiO{sub 3} Pebble Bed for a DEMO Blanket  

SciTech Connect (OSTI)

In development of the ceramic breeder blanket, the effective thermal conductivity of pebble beds is an important design parameter. For thermo-mechanical design of blanket, pebble beds were investigated used for Li{sub 2}TiO{sub 3} that was a candidate for tritium breeder. Li{sub 2}TiO{sub 3} pebble beds, whose size was 0.28-1.91 mm diameter, were measured on load under no neutron irradiation. The effective thermal conductivity was increased with load increasing was obtained.

Hatano, T.; Enoeda, M.; Suzuki, S.; Kosaku, Y.; Akiba, M. [Japan Atomic Energy Research Institute (Japan)

2003-07-15T23:59:59.000Z

170

Computational Efficient Upscaling Methodology for Predicting Thermal Conductivity of Nuclear Waste forms  

SciTech Connect (OSTI)

This study evaluated different upscaling methods to predict thermal conductivity in loaded nuclear waste form, a heterogeneous material system. The efficiency and accuracy of these methods were compared. Thermal conductivity in loaded nuclear waste form is an important property specific to scientific researchers, in waste form Integrated performance and safety code (IPSC). The effective thermal conductivity obtained from microstructure information and local thermal conductivity of different components is critical in predicting the life and performance of waste form during storage. How the heat generated during storage is directly related to thermal conductivity, which in turn determining the mechanical deformation behavior, corrosion resistance and aging performance. Several methods, including the Taylor model, Sachs model, self-consistent model, and statistical upscaling models were developed and implemented. Due to the absence of experimental data, prediction results from finite element method (FEM) were used as reference to determine the accuracy of different upscaling models. Micrographs from different loading of nuclear waste were used in the prediction of thermal conductivity. Prediction results demonstrated that in term of efficiency, boundary models (Taylor and Sachs model) are better than self consistent model, statistical upscaling method and FEM. Balancing the computation resource and accuracy, statistical upscaling is a computational efficient method in predicting effective thermal conductivity for nuclear waste form.

Li, Dongsheng; Sun, Xin; Khaleel, Mohammad A.

2011-09-28T23:59:59.000Z

171

Thermal-wave resonator cavity design and measurements of the thermal diffusivity of liquids  

E-Print Network [OSTI]

Thermal-wave resonator cavity design and measurements of the thermal diffusivity of liquids J. A for the measurement of the thermal diffusivity of liquids. The thermal diffusivities of distilled water, glycerol the thermal diffusivity of gases, particularly air,8,9 and vapors10 to a high degree of precision. Although

Mandelis, Andreas

172

THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystallineForeign Object DamageSystemsU.S. TALKS1THE WHITE 9086 THERMAL

173

First Results of Scanning Thermal Diffusivity Microscope (STDM) Measurements on Irradiated Monolithic and Dispersion Fuel  

SciTech Connect (OSTI)

The thermal conductivity of the fuel material in a reactor before and during irradiation is a sensitive and fundamental parameter for thermal hydraulic calculations that are useds to correctly determine fuel heat fluxes and meat temperatures and to simulate performance of the fuel elements during operation. Several techniques have been developed to measure the thermal properties of fresh fuel to support these calculations, but it is crucial to also investigate the change of thermal properties during irradiation.

T. K. Huber; M. K. Figg; J. R. Kennedy; A. B. Robinson; D. M. Wachs

2012-07-01T23:59:59.000Z

174

Serpentine Thermal Coupling Between a Stream and a Conducting Body  

SciTech Connect (OSTI)

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

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

2012-02-15T23:59:59.000Z

175

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

SciTech Connect (OSTI)

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

Du, Shiyu [Los Alamos National Laboratory; Andersson, Anders D. [Los Alamos National Laboratory; Germann, Timothy C. [Los Alamos National Laboratory; Stanek, Christopher R. [Los Alamos National Laboratory

2012-05-02T23:59:59.000Z

176

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

177

Mixed ionic and electronic conducting electrode studies for an alkali metal thermal to electric converter  

E-Print Network [OSTI]

This research focuses on preparation, kinetics, and performance studies of mixed ionic and electronic conducting electrodes (MIEE) applied in an alkali metal thermal to electric converter (AMTEC). Two types of MIEE, metal/sodium titanate and metal...

Guo, Yuyan

2009-05-15T23:59:59.000Z

178

LARGE SCALE PERMEABILITY TEST OF THE GRANITE IN THE STRIPA MINE AND THERMAL CONDUCTIVITY TEST  

E-Print Network [OSTI]

No.2 LARGE SCALE PERMEABILITY TEST OF THE GRANITE' IN THEMINE AND, THERMAL CONDUCTIVITY TEST Lars Lundstrom and HakanSUMMARY REPORT Background TEST SITE Layout of test places

Lundstrom, L.

2011-01-01T23:59:59.000Z

179

Geometry and temperature dependent thermal conductivity of diamond nanowires: A non-equilibrium molecular dynamics study  

E-Print Network [OSTI]

plasma etching of polycrystalline diamond films [7], microwave plasma assisted chemical vapor deposition. For theoretical calculations of proper- ties of nanosized diamond materials, polycrystalline diamond thin filmsGeometry and temperature dependent thermal conductivity of diamond nanowires: A non

Melnik, Roderick

180

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

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

Thermal and electrical conduction in the compaction direction of exfoliated graphite  

E-Print Network [OSTI]

Thermal and electrical conduction in the compaction direction of exfoliated graphite in the compaction direction of graphite-flake-based exfoliated graphite have been decoupled. The compact Exfoliated graphite is elongated graphite particles obtained by the exfoliation (typically involving rapid

Chung, Deborah D.L.

182

Lattice thermal conductivity of UO{sub 2} using ab-initio and classical molecular dynamics  

SciTech Connect (OSTI)

We applied the non-equilibrium ab-initio molecular dynamics and predict the lattice thermal conductivity of the pristine uranium dioxide for up to 2000?K. We also use the equilibrium classical molecular dynamics and heat-current autocorrelation decay theory to decompose the lattice thermal conductivity into acoustic and optical components. The predicted optical phonon transport is temperature independent and small, while the acoustic component follows the Slack relation and is in good agreement with the limited single-crystal experimental results. Considering the phonon grain-boundary and pore scatterings, the effective lattice thermal conductivity is reduced, and we show it is in general agreement with the sintered-powder experimental results. The charge and photon thermal conductivities are also addressed, and we find small roles for electron, surface polaron, and photon in the defect-free structures and for temperatures below 1500?K.

Kim, Hyoungchul [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136–791 (Korea, Republic of); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kaviany, Massoud, E-mail: kaviany@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2014-03-28T23:59:59.000Z

183

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

184

Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics  

SciTech Connect (OSTI)

In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to {approx}15% for ZnO-4% Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl2O4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2% Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.

Zhao, Yu [Bio-Inspired Materials and Devices Laboraory (BMDL); Yan, Yongke [Bio-Inspired Materials and Devices Laboraory (BMDL); Kumar, Ashok [Bio-Inspired Materials and Devices Laboraory (BMDL); Wang, Hsin [ORNL; Porter, Wallace D [ORNL

2012-01-01T23:59:59.000Z

185

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

E-Print Network [OSTI]

on the thermoelectric figure of merit (ZT) of a material defined as ZT S2 T=k, where S, , k, and T are the Seebeck by nanostructuring thermoelectric materials, and the key reason for increase in ZT was the reduction of thermalThermal Conductivity Reduction and Thermoelectric Figure of Merit Increase by Embedding

186

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

187

MAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS  

E-Print Network [OSTI]

-cooling with a closed-cycle refrigerator is an excellent option for relatively small superconducting systems. Since to energy consumption, mainly because the thermal loss associated with the storage and the transferMAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS H.-M. Chang and K

Chang, Ho-Myung

188

Mesoscopic simulations of phase distribution effects on the effective thermal conductivity of microgranular porous media.  

E-Print Network [OSTI]

of transport in open-cell metal foam. J. Heat Transfer ASMEopen-celled metal foam model for thermal applications. J. Heat Transferheat transfer is a non-negligible factor for thermal transports in high-porosity low-conductivity open-

Wang, Moran; Pan, Ning; Wang, Jinku; Chen, Shiyi

2007-01-01T23:59:59.000Z

189

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

190

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

SciTech Connect (OSTI)

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

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

2014-05-12T23:59:59.000Z

191

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

192

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

193

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

194

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

195

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

196

EFFECTIVE THERMAL CONDUCTIVITY OF LITHIUM CERAMIC PEBBLE BEDS FOR FUSION BLANKETS: A REVIEW  

E-Print Network [OSTI]

a significant interest as solid breeders for the fusion blankets during the last three decades. The solid for the fusion solid breeder blankets. In order to study the heat transfer in the blanket, effective conductivityEFFECTIVE THERMAL CONDUCTIVITY OF LITHIUM CERAMIC PEBBLE BEDS FOR FUSION BLANKETS: A REVIEW A. ABOU

Abdou, Mohamed

197

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

198

Thermal conductivity of Er{sup +3}:Y{sub 2}O{sub 3} films grown by atomic layer deposition  

SciTech Connect (OSTI)

Cross-plane thermal conductivity of 800, 458, and 110?nm erbium-doped crystalline yttria (Er{sup +3}:Y{sub 2}O{sub 3}) films deposited via atomic layer deposition was measured using the 3? method at room temperature. Thermal conductivity results show 16-fold increase in thermal conductivity from 0.49?W m{sup ?1}K{sup ?1} to 8?W m{sup ?1}K{sup ?1} upon post deposition annealing, partially due to the suppression of the number of the -OH/H{sub 2}O bonds in the films after annealing. Thermal conductivity of the annealed film was ?70% lower than undoped bulk single crystal yttria. The cumulative interface thermal resistivity of substrate-Er{sup +3}:Y{sub 2}O{sub 3}-metal heater was determined to be ?2.5?×?10{sup ?8} m{sup 2} K/W.

Raeisi Fard, Hafez; Hess, Andrew; Pashayi, Kamyar; Borca-Tasciuc, Theodorian, E-mail: borcat@rpi.edu [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Becker, Nicholas; Proslier, Thomas; Pellin, Michael [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)] [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)

2013-11-04T23:59:59.000Z

199

Lattice thermal conductivity of self-assembled PbTe-Sb2Te3 composites with nanometer lamellae Teruyuki Ikeda1  

E-Print Network [OSTI]

. In this work, the thermal conductivities and the electrical resistivities have been measured as functions for effective use of heat or electrical energy, it is essential to discover materials with a high thermoelectric to control the fraction transformed and inter-lamellar spacing. The electrical resistivity and the thermal

200

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

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

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

202

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

203

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

204

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

SciTech Connect (OSTI)

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

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

1986-05-01T23:59:59.000Z

205

Thermal properties of carbon nanowall layers measured by a pulsed photothermal technique  

SciTech Connect (OSTI)

We report the thermal properties of carbon nanowall layers produced by expanding beam radio-frequency plasma. The thermal properties of carbon nanowalls, grown at 600 Degree-Sign C on aluminium nitride thin-film sputtered on fused silica, were measured with a pulsed photo-thermal technique. The apparent thermal conductivity of the carbon at room temperature was found to increase from 20 to 80 Wm{sup -1} K{sup -1} while the thickness varied from 700 to 4300 nm, respectively. The intrinsic thermal conductivity of the carbon nanowalls attained 300 Wm{sup -1} K{sup -1} while the boundary thermal resistance with the aluminium nitride was 3.6 Multiplication-Sign 10{sup -8} Km{sup 2} W{sup -1}. These results identify carbon nanowalls as promising material for thermal management applications.

Achour, A.; Belkerk, B. E.; Ait Aissa, K.; Gautron, E.; Carette, M.; Jouan, P.-Y.; Brizoual, L. Le; Scudeller, Y.; Djouadi, M.-A. [Institut des Materiaux Jean Rouxel, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes cedex 3 (France)] [Institut des Materiaux Jean Rouxel, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes cedex 3 (France); Vizireanu, S.; Dinescu, G. [National Institute for Laser, Plasma and Radiation Physics, Magurele MG-36, RO-077125 Bucharest (Romania)] [National Institute for Laser, Plasma and Radiation Physics, Magurele MG-36, RO-077125 Bucharest (Romania)

2013-02-11T23:59:59.000Z

206

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

207

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.

208

Role of anisotropic thermal conductivity in the reversed-field pinch dynamics  

SciTech Connect (OSTI)

Two compressible magnetohydrodynamics simulations of the reversed-field pinch are performed, with isotropic and anisotropic thermal conductivity. We describe in detail the numerical method we use to reproduce the effect of a large parallel thermal conductivity, which makes magnetic field lines almost isothermal. We compare the results of the two simulations, showing that the anisotropic thermal conductivity causes the formation of a hot island when closed magnetic surfaces exist, while temperature becomes almost uniform when the magnetic field is chaotic. After a transient single-helicity state that is formed in the initial phase, a stationary state is reached where the RFP configuration exists in a multiple helicity state, even though the Hartmann number is below the threshold found in previous simulations for the formation of multiple helicity states.

Onofri, M.; Malara, F.; Veltri, P. [Dipartimento di Fisica, Universita della Calabria, ponte P. Bucci, Cubo 31C, 87036 Rende (Italy)

2011-05-15T23:59:59.000Z

209

Simple, accurate, and precise measurements of thermal diffusivity in liquids using a thermal-wave cavity  

E-Print Network [OSTI]

Simple, accurate, and precise measurements of thermal diffusivity in liquids using a thermal, and its application to the evaluation of the thermal diffusivity of liquids is described. The simplicity agreement was found with reported results in the literature. The accuracy of the thermal diffusivity

Mandelis, Andreas

210

Assembly for electrical conductivity measurements in the piston cylinder device  

DOE Patents [OSTI]

An assembly apparatus for measurement of electrical conductivity or other properties of a sample in a piston cylinder device wherein pressure and heat are applied to the sample by the piston cylinder device. The assembly apparatus includes a body, a first electrode in the body, the first electrode operatively connected to the sample, a first electrical conductor connected to the first electrode, a washer constructed of a hard conducting material, the washer surrounding the first electrical conductor in the body, a second electrode in the body, the second electrode operatively connected to the sample, and a second electrical conductor connected to the second electrode.

Watson, Heather Christine (Dublin, CA); Roberts, Jeffrey James (Livermore, CA)

2012-06-05T23:59:59.000Z

211

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.

212

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

SciTech Connect (OSTI)

The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in x-ray diffraction after ion irradiation up to 5×1016 He2+/cm2 at low-temperature (< 200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 µm thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 µm) in the sample subjected to 5×1016 He2+/cm2, the highest fluence reached, while similar features were not detected at 9×1015 He2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55 % for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.

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

2014-11-01T23:59:59.000Z

213

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

SciTech Connect (OSTI)

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

214

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

215

Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities  

E-Print Network [OSTI]

is underestimated. For picolitre droplets however, convective heat transfer due to internal flows is negligible compared to conduc- tion. The relative effect of convection and conduction is seen in the Pe´clet number, Pe = uR/K, where K is the thermal diffusivity...

Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D.

2012-01-01T23:59:59.000Z

216

Thermal conductivity of large-grain niobium and its effect on trapped vortices in the temperature range 1.8?5 K  

SciTech Connect (OSTI)

Experimental investigation of the thermal conductivity of large grain and its dependence on the trapped vortices in parallel magnetic field with respect to the temperature gradient {gradient}T was carried out on four large-grain niobium samples from four different ingots. The zero-field thermal conductivity measurements are in good agreement with the measurements based on the theory of Bardeen-Rickayzen-Tewordt (BRT). The change in thermal conductivity with trapped vortices is analysed with the field dependence of the conductivity results of Vinen et al for low inductions and low-temperature situation. Finally, the dependence of thermal conductivity on the applied magnetic field in the vicinity of the upper critical field H{sub c2} is fitted with the theory of pure type-II superconductor of Houghton and Maki. Initial remnant magnetization in the sample shows a departure from the Houghton?Maki curve whereas the sample with zero trapped flux qualitatively agrees with the theory. A qualitative discussion is presented explaining the reason for such deviation from the theory. It has also been observed that if the sample with the trapped vortices is cycled through T{sub c}, the subsequent measurement of the thermal conductivity coincides with the zero trapped flux results.

Mondal, Jayanta [Bhabha Atomic Research Centre; Ciovati, Gianluigi [JLAB; Mittal, Kailash C. [Bhabha Atomic Research Centre; Myneni, Ganapati Rao [JLAB

2012-04-01T23:59:59.000Z

217

Measurement and modeling thermal conductivity of baked products  

E-Print Network [OSTI]

for serving on my advisory committee and lending their comments and criticisms. I would like to thank El Consejo Vacional de Ciencia. y Tecnologia de Mex- ico, CONACYT, for the financial support that made this tremendous opportunity possible. Finally, I... want to thank El Centro de Investigacion y Desarrollo, A. C. , CIAD, A. C. , Sonora. , Mexico, especially Dr. Carlos Pena, for his encouragement and support to reach this goal. DEDICATION I dedicate this to my wonderful family: my parents, brothers...

Islas Rubio, Alma Rosa

1990-01-01T23:59:59.000Z

218

Measurement of Thermal Diffusivity and Conductivity in Advanced Nanostructured Materials  

E-Print Network [OSTI]

in Magnetic Materials . . . . . . . . . . . . . . . viimportants of understanding materials properties typicallyY.S. Ju, Annual Review of Materials Science, 29, 261 (1999).

Teweldebrhan, Desalegne Bekuretsion

2012-01-01T23:59:59.000Z

219

Atomistic calculation of the thermal conductance of large scale bulk-nanowire junctions  

SciTech Connect (OSTI)

We have developed a stable and efficient kernel method to compute thermal transport in open systems, based on the scattering-matrix approach. This method is applied to compute the thermal conductance of a junction between bulk silicon and silicon nanowires with diameter up to 10 nm. We have found that beyond a threshold diameter of 7 nm, transmission spectra and contact conductances scale with the cross section of the contact surface, whereas deviations from this general trend are observed in thinner wires. This result allows us to predict the thermal resistance of bulk-nanowire interfaces with larger cross sections than those tractable with atomistic simulations, and indicate the characteristic size beyond which atomistic systems can in principle be treated accurately by mean-field theories. Our calculations also elucidate how dimensionality reduction and shape affect interfacial heat transport.

Duchemin, Ivan; Donadio, Davide [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany)

2011-09-15T23:59:59.000Z

220

Advancing Reactive Tracer Methods for Measuring Thermal Evolution...  

Open Energy Info (EERE)

Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- and Water-Based Geothermal Reservoirs Geothermal Lab Call Project Jump to: navigation, search Last...

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

Experimental investigation of size effect on thermal conductivity for ultra-thin amorphous poly(methyl methacrylate) (PMMA) films  

E-Print Network [OSTI]

An investigation was conducted to determine whether a “size effect” phenomenon for one particular thermophysical property, thermal conductivity, actually exists for amorphous poly(methyl methacrylate) (PMMA) films with thicknesses ranging from 40 nm...

Kim, Ick Chan

2009-05-15T23:59:59.000Z

222

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

SciTech Connect (OSTI)

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

Henager, Charles H.; Nguyen, Ba Nghiep

2013-04-19T23:59:59.000Z

223

Effect of phonon confinement on lattice thermal conductivity of lead Telluride quantum well structure  

SciTech Connect (OSTI)

The paper examines the effect of spatial confinement of acoustic phonons on average group velocity and consequently the lattice thermal conductivity of a free-standing PbTe quantum well structure and their temperature dependence. The average group velocity at 100 Å decreases 30% to the bulk value and falls more rapidly on reducing the width of quantum well. Moreover, the lattice thermal conductivity of 100 Å wide PbTe quantum well with value of 0.60 W/mK shows considerable decrease of 70% compared to it’s bulk value. It is observed that the effect of reduction in well width is less pronounce as temperature increases. This appears mainly due to dominance of umklapp processes over the confinement effects.

Tripathi, Madhvendra Nath, E-mail: ommadhav27@gmail.com [Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur-495009, Chhattisgarh (India)

2014-04-24T23:59:59.000Z

224

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

225

Infrared Thermography Measurements of Window Thermal Test Specimen Surface Temperatures  

E-Print Network [OSTI]

Infrared Thermography Measurements of Window Thermal Test Specimen Surface Temperatures Brent T Temperatures of Window Specimens: Infrared Thermography Laboratory Measurements Brent T. Griffith1 , Howdy and cold sides, respectively. Surface temperature maps were compiled using an infrared thermographic system

226

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]

resistance and to maintain high ground thermal conductivity around the cable even under very dry ground#12;1981). Their basic solution is to find a suitable backfilling material to minimize the contact thermal conductivity for clay backfilling, measured 1/2 inch and 6 inches (1.3 and 15 cm) away from

Oak Ridge National Laboratory

227

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

E-Print Network [OSTI]

of the vapor deposition process when using soft metallic coatings so that the maximum allowable enhancement for a specific coating thickness can be obtained. Also, the temperature dependence for the microhardness of copper was ex- perimentally determined...- sate for the difFerence in layer and substrate thermal conductivities. When applied, the model agreed well with the data obtained in this investigation at low coating thick- ness but overpredicted the data, as the thickness increased. In addition...

Ochterbeck, Jay Matthew

1990-01-01T23:59:59.000Z

228

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

229

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

230

Thermal conductance between an SWNT and Lennard-Jones fluid Yasuhiro Igarashi, Junichiro Shiomi and Shigeo Maruyama  

E-Print Network [OSTI]

Thermal conductance between an SWNT and Lennard-Jones fluid Yasuhiro Igarashi, Junichiro Shiomi and Shigeo Maruyama Department of Mechanical Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Thermal conductance between an SWNT and Lennard-Jones fluid is studied

Maruyama, Shigeo

231

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

232

Accepted by the Journal of Building Physics (2007) Microstructure and Thermal Conductivity of Hydrated Calcium Silicate Board Materials  

E-Print Network [OSTI]

of Hydrated Calcium Silicate Board Materials Chi T. Do, Dale P. Bentz1 , and Paul E. Stutzman Building and pore size are examined for two calcium silicate boards of different densities. Thermal conductivities; radiation; thermal conductivity. Introduction In recent years, a variety of low-density calcium silicate

Bentz, Dale P.

233

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.

234

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

235

Front surface thermal property measurements of air plasma spray coatings  

SciTech Connect (OSTI)

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

236

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

SciTech Connect (OSTI)

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

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

2013-06-01T23:59:59.000Z

237

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

SciTech Connect (OSTI)

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

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

2014-05-01T23:59:59.000Z

238

Method for measuring thermal properties using a long-wavelength infrared thermal image  

DOE Patents [OSTI]

A method for estimating the thermal properties of surface materials using long-wavelength thermal imagery by exploiting the differential heating histories of ground points in the vicinity of shadows. The use of differential heating histories of different ground points of the same surface material allows the use of a single image acquisition step to provide the necessary variation in measured parameters for calculation of the thermal properties of surface materials.

Walker, Charles L. (Albuquerque, NM); Costin, Laurence S. (Albuquerque, NM); Smith, Jody L. (Albuquerque, NM); Moya, Mary M. (Albuquerque, NM); Mercier, Jeffrey A. (Albuquerque, NM)

2007-01-30T23:59:59.000Z

239

Measurements of Electron Thermal Transport due to Electron Temperature Gradient Modes in a Basic Experiment  

SciTech Connect (OSTI)

Production and identification of electron temperature gradient modes have already been reported [X. Wei, V. Sokolov, and A. K. Sen, Phys. Plasmas 17, 042108 (2010)]. Now a measurement of electron thermal conductivity via a unique high frequency triple probe yielded a value of {chi}{sub perpendiculare} ranging between 2 and 10 m{sup 2}/s, which is of the order of a several gyrobohm diffusion coefficient. This experimental result appears to agree with a value of nonlocal thermal conductivity obtained from a rough theoretical estimation and not inconsistent with gyrokinetic simulation results for tokamaks. The first experimental scaling of the thermal conductivity versus the amplitude of the electron temperature gradient fluctuation is also obtained. It is approximately linear, indicating a strong turbulence signature.

Sokolov, V.; Sen, A. K. [Plasma Research Laboratory, Columbia University, New York, New York 10027 (United States)

2011-10-07T23:59:59.000Z

240

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

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

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

Cable, William; Romanovsky, Vladimir

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

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

SciTech Connect (OSTI)

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

Cable, William; Romanovsky, Vladimir

2014-03-31T23:59:59.000Z

242

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

243

Coupled heat conduction and thermal stress formulation using explicit integration. [LMFBR  

SciTech Connect (OSTI)

The formulation needed for the conductance of heat by means of explicit integration is presented. The implementation of these expressions into a transient structural code, which is also based on explicit temporal integration, is described. Comparisons of theoretical results with code predictions are given both for one-dimensional and two-dimensional problems. The coupled thermal and structural solution of a concrete crucible, when subjected to a sudden temperature increase, shows the history of cracking. The extent of cracking is compared with experimental data.

Marchertas, A.H.; Kulak, R.F.

1982-06-01T23:59:59.000Z

244

Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance  

E-Print Network [OSTI]

Electrical, Frequency and Thermal Measurement and Modelling of Supercapacitor Performance Yasser--This paper presents an evaluation of commercial supercapacitors performance (ESR, C, self-discharge, Pmax, Emax, coulumbic efficiency, etc), under different conditions. Characterization of supercapacitor

Paris-Sud XI, Université de

245

Thermal emission microscopy measures the spa-tial distribution of temperature in a sample. Thermal  

E-Print Network [OSTI]

per unit area emitted by an object is proportional to its absolute temperature to the fourth powerThermal emission microscopy measures the spa- tial distribution of temperature in a sample. Thermal- cause the optical power emitted by the sample is a function of its local temperature. The optical power

246

MODELING THE TRANSVERSE THERMAL CONDUCTIVITY OF 2D-SICF/SIC COMPOSITES  

SciTech Connect (OSTI)

A hierarchical model was developed to describe the effective transverse thermal conductivity, K effective, of a 2D-SiC/SiC composite made from stacked and infiltrated woven fabric layers in terms of constituent properties and microstructural and architectural variables. The model includes the expected effects of fiber-matrix interfacial conductance as well as the effects of high fiber packing fractions within individual tows and the non-uniform nature of 2D-fabric layers that include a significant amount of interlayer porosity. Model predictions were obtained for two versions of DuPont 2D-Hi Nicalon(Trademark)/PyC/ICVI-SiC composite, one with a thin (0.110 micron) and the other with a thick (1.040 micron) PyC fiber coating. The model predicts that the matrix porosity content and porosity shape factor have a major influence on K effective(T) for such a composite.

Youngblood, Gerald E.; Senor, David J.; Jones, Russell H.

2002-09-01T23:59:59.000Z

247

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

E-Print Network [OSTI]

materials (PCM) in solar thermal concentrating technologyeffective and efficient solar thermal electricity generatorbeen considered for solar thermal energy storages. These are

Roshandell, Melina

2013-01-01T23:59:59.000Z

248

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

249

Thermal imaging measurement of lateral thermal diffusivity in continuous fiber ceramic composites  

SciTech Connect (OSTI)

Infrared thermal imaging has become a common technique for nondestructive evaluation and measurement of thermal properties in ceramic specimens. Flash thermal imaging can be used to determine two-dimensional through-thickness thermal diffusivity in a planar specimen. In this study, the authors extended the method to determine lateral, or transverse, thermal diffusivity in the specimen. During the flash thermal imaging test, pulsed heat energy is applied to a specimen's back surface, which is partially shielded, and the change of temperature distribution on the front surface is monitored by an infrared thermal imaging system. The temperature distribution represents the effect of both the normal heat transfer through the specimen's thickness and the lateral heat transfer through the interface between the shielded and unshielded back-surface regions. Those temperature distributions are then fitted with a theoretical solution of the heat transfer process to determine the lateral thermal diffusivity at the interface. This technique has been applied to measure lateral thermal diffusivity in a steel plate and a continuous fiber ceramic composite specimen.

Sun, J. G.; Deemer, C.; Ellingson, W. A.

2000-02-18T23:59:59.000Z

250

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

251

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

252

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

SciTech Connect (OSTI)

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

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

2014-02-21T23:59:59.000Z

253

Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process  

E-Print Network [OSTI]

Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...

Zuo, Yanjia

2010-01-01T23:59:59.000Z

254

Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process .  

E-Print Network [OSTI]

??Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The… (more)

Zuo, Yanjia

2010-01-01T23:59:59.000Z

255

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

256

Temperature measurements using multicolor pyrometry in thermal radiation heating environments  

SciTech Connect (OSTI)

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

257

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

258

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-source...

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

2006-01-01T23:59:59.000Z

259

Thermal diffusivity measurements in liquids using signal common-mode-rejection demodulation in a thermal-wave cavity  

E-Print Network [OSTI]

Thermal diffusivity measurements in liquids using signal common-mode- rejection demodulation Mandelis et al., Rev. Sci. Instrum. 71, 2440 2000 has been used to make direct absolute thermal diffusivity, yielding a high-resolution technique for thermal diffusivity measurements in liquids. The thermal

Mandelis, Andreas

260

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

SciTech Connect (OSTI)

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

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

1998-11-01T23:59:59.000Z

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

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

262

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

E-Print Network [OSTI]

The objective of this work was to evaluate a new high conductivity nuclear fuel form. Uranium dioxide (UO2) is a very effective nuclear fuel, but it’s performance is limited by its low thermal conductivity. The fuel concept considered here is a...

Naramore, Michael J

2010-08-03T23:59:59.000Z

263

Method of making improved gas storage carbon with enhanced thermal conductivity  

DOE Patents [OSTI]

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

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

2002-11-05T23:59:59.000Z

264

On linearization and preconditioning for radiation diffusion coupled to material thermal conduction equations  

SciTech Connect (OSTI)

Jacobian-free Newton–Krylov (JFNK) method is an effective algorithm for solving large scale nonlinear equations. One of the most important advantages of JFNK method is that there is no necessity to form and store the Jacobian matrix of the nonlinear system when JFNK method is employed. However, an approximation of the Jacobian is needed for the purpose of preconditioning. In this paper, JFNK method is employed to solve a class of non-equilibrium radiation diffusion coupled to material thermal conduction equations, and two preconditioners are designed by linearizing the equations in two methods. Numerical results show that the two preconditioning methods can improve the convergence behavior and efficiency of JFNK method.

Feng, Tao, E-mail: fengtao2@mail.ustc.edu.cn [School of Mathematical Sciences, University of Science and Technology of China, Hefei 230052 (China) [School of Mathematical Sciences, University of Science and Technology of China, Hefei 230052 (China); Graduate School of China Academy Engineering Physics, Beijing 100083 (China); An, Hengbin, E-mail: an_hengbin@iapcm.ac.cn [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, Xijun, E-mail: yuxj@iapcm.ac.cn [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Li, Qin, E-mail: liqin@lsec.cc.ac.cn [Chinese Academy of Mathematics and Systems Science, Beijing 100190 (China)] [Chinese Academy of Mathematics and Systems Science, Beijing 100190 (China); Zhang, Rongpei, E-mail: zhangrongpei@163.com [Graduate School of China Academy Engineering Physics, Beijing 100083 (China)] [Graduate School of China Academy Engineering Physics, Beijing 100083 (China)

2013-03-01T23:59:59.000Z

265

Investigation into the effect of heat treatment on the thermal conductivity of 3-D carbon/carbon fiber composites  

SciTech Connect (OSTI)

The material used in this study was a carbon-carbon fiber composite manufactured from precursor yarn and petroleum based pitch through a process of repetitive densification of a woven preform. The resultant high temperature-high strength material exhibits relatively high thermal conductivity and is thus of interest to the fusion energy, plasma materials interactions (PMI) and plasma facing components (PFC) communities. Carbon-carbon fiber composite manufacture involves two distinct processes, preform weaving and component densification. In this study three samples were subjected to an additional heat treatment of 2550, 2750 or 3000{degree}C at Oak Ridge National Laboratory (ORNL) subsequent to their fourth graphitization at 2400{degree}C. It should be noted that no effort was made to optimize the composite for thermal conductivity, but rather only to provide a material with which to evaluate the effect of the final heat treatment temperature on the thermal conductivity. The fiber is the primary source of heat conduction in the composite. Consequently, increasing the fiber volume fraction, and/or the fiber thermal conductivity is expected to increase the composite thermal conductivity. 3 refs., 1 fig.

Dinwiddie, R.B.; Burchell, T.D. (Oak Ridge National Lab., TN (USA)); Baker, C.F. (Fiber Materials, Inc., Biddeford, ME (USA))

1991-01-01T23:59:59.000Z

266

Microstructure and thermal conductivity of surfactant-free NiO nanostructures  

SciTech Connect (OSTI)

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

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

2012-06-15T23:59:59.000Z

267

Thermal imaging measurement and correlation of thermal diffusivity in continuous fiber ceramic composites  

SciTech Connect (OSTI)

Continuous fiber ceramic matrix composites (CFCCs) are currently being developed for a variety of high-temperature applications, including use in advanced heat engines. For such composites, knowledge of porosity distribution and presence of defects is important for optimizing mechanical and thermal behavior of the components. The assessment of porosity and its distribution is also necessary during composite processing to ensure component uniformity. To determine the thermal properties of CFCC materials, and particularly for detecting defects and nonuniformities, the authors have developed an infrared thermal imaging method to provide a single-shot full-field measurement of thermal diffusivity distributions in large components. This method requires that the back surface of a specimen receives a thermal pulse of short duration and that the temperature of the front surface is monitored as a function of time. The system has been used to measure thermal diffusivities of several CFCC materials with known porosity or density values, including SYLRAMIC{trademark} SiC/SiNC composite samples from Dow Corning and SiC/SiC and enhanced SiC/SiC samples from DuPont Lanxide Composites, to determine the relationship of thermal diffusivity to component porosity or density.

Sun, J.G.; Deemer, C.; Ellingson, W.A. [Argonne National Lab., IL (United States). Energy Technology Div.; Easler, T.E.; Szweda, A. [Dow Corning Corp., Midland, MI (United States); Craig, P.A. [DuPont Lanxide Composites Inc., Newark, DE (United States)

1997-09-01T23:59:59.000Z

268

Contactless measurement of alternating current conductance in quantum Hall structures  

SciTech Connect (OSTI)

We report a procedure to determine the frequency-dependent conductance of quantum Hall structures in a broad frequency domain. The procedure is based on the combination of two known probeless methods—acoustic spectroscopy and microwave spectroscopy. By using the acoustic spectroscopy, we study the low-frequency attenuation and phase shift of a surface acoustic wave in a piezoelectric crystal in the vicinity of the electron (hole) layer. The electronic contribution is resolved using its dependence on a transverse magnetic field. At high frequencies, we study the attenuation of an electromagnetic wave in a coplanar waveguide. To quantitatively calibrate these data, we use the fact that in the quantum-Hall-effect regime the conductance at the maxima of its magnetic field dependence is determined by extended states. Therefore, it should be frequency independent in a broad frequency domain. The procedure is verified by studies of a well-characterized p-SiGe/Ge/SiGe heterostructure.

Drichko, I. L.; Diakonov, A. M.; Malysh, V. A.; Smirnov, I. Yu.; Ilyinskaya, N. D.; Usikova, A. A. [A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Galperin, Y. M. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo (Norway); A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Kummer, M.; Känel, H. von [Laboratorium für Festkörperphysik ETH Zürich, CH-8093 Zürich (Switzerland)

2014-10-21T23:59:59.000Z

269

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

2014-04-23T23:59:59.000Z

270

MODELING THE TRANSVERSE THERMAL CONDUCTIVITY OF 3D-SICF/SIC COMPOSITES  

SciTech Connect (OSTI)

Our previously developed hierarchical two-layer (H2L) model was modified to describe the effective transverse thermal conductivity (Keff) of a three-dimensional (3D) SiC/SiC composite plate made with cross-layered and Z-stitched X:Y:Z uniaxial fiber tow sub-units. As before, the model describes Keff in terms of constituent, microstructural and architectural properties that include the expected effects of fiber-matrix interfacial conductance, of high fiber packing fractions within individual tow sub-units and of the non-uniform porosity contents, shapes and orientations within these sub-units. Model predictions were obtained for two versions of a 3D-Tyranno SA?/PyC/ICVI-SiC composite that had similar fiber/matrix pyrocarbon (PyC) interfaces, relatively high bulk densities (~2.88 g/cc), and an X:Y configuration with fiber content ratios 1:1. The only major difference between the two versions was their Z-stitch fiber content where the relative fiber ratios were 0.1 and 1.2 in the Z sub-units.

Youngblood, Gerald E.; Jones, Russell H.; Yamada, Reiji

2004-06-30T23:59:59.000Z

271

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

SciTech Connect (OSTI)

Uranium dioxide (UO2) is the most common fuel material in commercial nuclear power reactors. Despite its numerous advantages such as high melting point, good high-temperature stability, good chemical compatibility with cladding and coolant, and resistance to radiation, it suffers from low thermal conductivity that can result in large temperature gradients within the UO2 fuel pellet, causing it to crack and release fission gases. Thermal swelling of the pellets also limits the lifetime of UO2 fuel in the reactor. To mitigate these problems, we propose to develop novel UO2 fuel with uniformly distributed carbon nanotubes (CNTs) that can provide high-conductivity thermal pathways and can eliminate fuel cracking and fission gas release due to high temperatures. CNTs have been investigated extensively for the past decade to explore their unique physical properties and many potential applications. CNTs have high thermal conductivity (6600 W/mK for an individual single- walled CNT and >3000 W/mK for an individual multi-walled CNT) and high temperature stability up to 2800°C in vacuum and about 750°C in air. These properties make them attractive candidates in preparing nano-composites with new functional properties. The objective of the proposed research is to develop high thermal conductivity of UO2–CNT composites without affecting the neutronic property of UO2 significantly. The concept of this goal is to utilize a rapid sintering method (5–15 min) called spark plasma sintering (SPS) in which a mixture of CNTs and UO2 powder are used to make composites with different volume fractions of CNTs. Incorporation of these nanoscale materials plays a fundamentally critical role in controlling the performance and stability of UO2 fuel. We will use a novel in situ growth process to grow CNTs on UO2 particles for rapid sintering and develop UO2-CNT composites. This method is expected to provide a uniform distribution of CNTs at various volume fractions so that a high thermally conductive UO2-CNT composite is obtained with a minimal volume fraction of CNTs. The mixtures are sintered in the SPS facility at a range of temperatures, pressures, and time durations so as to identify the optimal processing conditions to obtain the desired microstructure of sintered UO2-CNT pellets. The second objective of the proposed work is to identify the optimal volume fraction of CNTs in the microstructure of the composites that provides the desired high thermal conductivity yet retaining the mechanical strength required for efficient function as a reactor fuel. We will systematically study the resulting microstructure (grain size, porosity, distribution of CNTs, etc.) obtained at various SPS processing conditions using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscope (TEM). We will conduct indentation hardness measurements and uniaxial strength measurements as a function of volume fraction of CNTs to determine the mechanical strength and compare them to the properties of UO2. The fracture surfaces will be studied to determine the fracture characteristics that may relate to the observed cracking during service. Finally, we will perform thermal conductivity measurements on all the composites up to 1000° C. This study will relate the microstructure, mechanical properties, and thermal properties at various volume fractions of CNTs. The overall intent is to identify optimal processing conditions that will provide a well-consolidated compact with optimal microstructure and thermo-mechanical properties. The deliverables include: (1) fully characterized UO2-CNT composite with optimal CNT volume fraction and high thermal conductivity and (2) processing conditions for production of UO2-CNT composite pellets using SPS method.

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

2014-03-10T23:59:59.000Z

272

Comparison of Different Upscaling Methods for Predicting Thermal Conductivity of Complex Heterogeneous Materials System: Application on Nuclear Waste Forms  

SciTech Connect (OSTI)

To develop a strategy in thermal conductivity prediction of a complex heterogeneous materials system, loaded nuclear waste forms, the computational efficiency and accuracy of different upscaling methods have been evaluated. The effective thermal conductivity, obtained from microstructure information and local thermal conductivity of different components, is critical in predicting the life and performance of waste form during storage. Several methods, including the Taylor model, Sachs model, self-consistent model, and statistical upscaling method, were developed and implemented. Microstructure based finite element method (FEM) prediction results were used to as benchmark to determine the accuracy of the different upscaling methods. Micrographs from waste forms with varying waste loadings were used in the prediction of thermal conductivity in FEM and homogenization methods. Prediction results demonstrated that in term of efficiency, boundary models (e.g., Taylor model and Sachs model) are stronger than the self-consistent model, statistical upscaling method, and finite element method. However, when balancing computational efficiency and accuracy, statistical upscaling is a useful method in predicting effective thermal conductivity for nuclear waste forms.

Li, Dongsheng; Sun, Xin; Khaleel, Mohammad A.

2012-06-16T23:59:59.000Z

273

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.

274

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.

275

Numerical investigation of CO{sub 2} emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe of variable thermal conductivity  

SciTech Connect (OSTI)

In this paper the CO{sub 2} emission and thermal stability in a long cylindrical pipe of combustible reactive material with variable thermal conductivity are investigated. It is assumed that the cylindrical pipe loses heat by both convection and radiation at the surface. The nonlinear differential equations governing the problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique method. The effects of various thermophysical parameters on the temperature and carbon dioxide fields, together with critical conditions for thermal ignition are illustrated and discussed quantitatively.

Lebelo, Ramoshweu Solomon, E-mail: sollyl@vut.ac.za [Department of Mathematics, Vaal University of Technology, Private Bag X021, Vanderbijlpark, 1911 (South Africa)

2014-10-24T23:59:59.000Z

276

Camera-based reflectivity measurement for solar thermal applications  

E-Print Network [OSTI]

of the solar-weighted reflectivity of the receiver component in CSP systems. Such reflectivity measurement Tubular receivers for solar thermal power plants, specifically tower plants, are in common use, in plants to be able to do conveniently in the field, possibly at intervals throughout the life of the plant

277

Spectral measurement of the thermal excitation of a superconducting qubit  

E-Print Network [OSTI]

Spectral measurement of the thermal excitation of a superconducting qubit A. Palacios-Laloy, F of a superconducting qubit 2 Superconducting qubits [1] are promising candidates for implementing a solid- state lying in their ground state. In most superconducting qubit experiments, the initialization is simply

Boyer, Edmond

278

Conduction Effect of Thermal Radiation in a Metal Shield Pipe in a Cryostat for a Cryogenic Interferometric Gravitational Wave Detector  

E-Print Network [OSTI]

A large heat load caused by thermal radiation through a metal shield pipe was observed in a cooling test of a cryostat for a prototype of a cryogenic interferometric gravitational wave detector. The heat load was approximately 1000 times larger than the value calculated by the Stefan-Boltzmann law. We studied this phenomenon by simulation and experiment and found that it was caused by the conduction of thermal radiation in a metal shield pipe.

Takayuki Tomaru; Masao Tokunari; Kazuaki Kuroda; Takashi Uchiyama; Akira Okutomi; Masatake Ohashi; Hiroyuki Kirihara; Nobuhiro Kimura; Yoshio Saito; Nobuaki Sato; Takakazu Shintomi; Toshikazu Suzuki; Tomiyoshi Haruyama; Shinji Miyoki; Kazuhiro Yamamoto; Akira Yamamoto

2007-11-06T23:59:59.000Z

279

Anisotropic thermal conduction in polymer melts in uniaxial elongation Sahil Gupta, Jay D. Schieber, and David C. Venerus  

E-Print Network [OSTI]

diffusivity tensor as a function of strain and strain rate. The thermal diffusivity is found to increase Published by the The Society of Rheology Related Articles A thin-filament melt spinning model with radial based on forced Rayleigh scattering is used to measure the two independent components of the thermal

Schieber, Jay D.

280

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

SciTech Connect (OSTI)

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

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

2014-03-17T23:59:59.000Z

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

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

SciTech Connect (OSTI)

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

282

DIRECT MEASUREMENT OF HEAT FLUX FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect (OSTI)

Laboratory experiments show a linear relationship between the total heat flux from a water surface to air and the standard deviation of the surface temperature field, {sigma}, derived from thermal images of the water surface over a range of heat fluxes from 400 to 1800 Wm{sup -2}. Thermal imagery and surface data were collected at two power plant cooling lakes to determine if the laboratory relationship between heat flux and {sigma} exists in large heated bodies of water. The heat fluxes computed from the cooling lake data range from 200 to 1400 Wm{sup -2}. The linear relationship between {sigma} and Q is evident in the cooling lake data, but it is necessary to apply band pass filtering to the thermal imagery to remove camera artifacts and non-convective thermal gradients. The correlation between {sigma} and Q is improved if a correction to the measured {sigma} is made that accounts for wind speed effects on the thermal convection. Based on more than a thousand cooling lake images, the correlation coefficients between {sigma} and Q ranged from about 0.8 to 0.9.

Garrett, A; Eliel Villa-Aleman, E; Robert Kurzeja, R; Malcolm Pendergast, M; Timothy Brown, T; Saleem Salaymeh, S

2007-12-19T23:59:59.000Z

283

MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect (OSTI)

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

284

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.

285

Effective Thermal Conductivity of Soda-Lime Silicate Glassmelts with Different Iron Contents Between 1100C and 1500C  

E-Print Network [OSTI]

Effective Thermal Conductivity of Soda-Lime Silicate Glassmelts with Different Iron Contents collected for soda- lime silicate glasses with iron content ranging from 0.008 to 1.1 wt% and temperatures, refractory walls wear more rapidly for clear glassmelts compared with colored ones.1 Soda-lime silicate glass

Pilon, Laurent

286

Hyper-resistivity and electron thermal conductivity due to destroyed magnetic surfaces in axisymmetric plasma equilibria  

SciTech Connect (OSTI)

In order to model the effects of small-scale current-driven magnetic fluctuations in a mean-field theoretical description of a large-scale plasma magnetic field B(x,t), a space and time dependent hyper-resistivity {Lambda}(x,t) can be incorporated into the Ohm's law for the parallel electric field E Dot-Operator B. Using Boozer coordinates, a theoretical method is presented that allows for a determination of the hyper-resistivity {Lambda}({psi}) functional dependence on the toroidal magnetic flux {psi} for arbitrary experimental steady-state Grad-Shafranov axisymmetric plasma equilibria, if values are given for the parallel plasma resistivity {eta}({psi}) and the local distribution of any auxiliary plasma current. Heat transport in regions of plasma magnetic surfaces destroyed by resistive tearing modes can then be modeled by an electron thermal conductivity k{sub e}({psi})=({epsilon}{sub 0}{sup 2}m{sub e}/e{sup 2}){Lambda}({psi}), where e and m{sub e} are the electron charge and mass, respectively, while {epsilon}{sub 0} is the permittivity of free space. An important result obtained for axisymmetric plasma equilibria is that the {psi}{psi}-component of the metric tensor of Boozer coordinates is given by the relation g{sup {psi}{psi}}({psi}){identical_to}{nabla}{psi} Dot-Operator {nabla}{psi}=[{mu}{sub 0}G({psi})][{mu}{sub 0}I({psi})]/{iota}({psi}), with {mu}{sub 0} the permeability of free space, G({psi}) the poloidal current outside a magnetic surface, I({psi}) the toroidal current inside a magnetic surface, and {iota}({psi}) the rotational transform.

Weening, R. H. [Department of Radiologic Sciences, Thomas Jefferson University, 901 Walnut Street, Philadelphia, Pennsylvania 19107-5233 (United States)

2012-06-15T23:59:59.000Z

287

Thermal conductivity of the quark matter for the SU(2) light-flavor sector  

E-Print Network [OSTI]

We investigate the thermal conductivity ($\\kappa$) of the quark matter at finite quark chemical potential $(\\mu)$ and temperature $(T)$, employing the Green-Kubo formula, for the SU(2) light-flavor sector with the finite current-quark mass $m=5$ MeV. As a theoretical framework, we construct an effective thermodynamic potential from the $(\\mu,T)$-modified liquid-instanton model (mLIM). Note that all the relevant model parameters are designated as functions of $T$, using the trivial-holonomy caloron solution. By solving the self-consistent equation of mLIM, we acquire the constituent-quark mass $M_0$ as a function of $T$ and $\\mu$, satisfying the universal-class patterns of the chiral phase transition. From the numerical results for $\\kappa$, we observe that there emerges a peak at $\\mu\\approx200$ MeV for the low-$T$ region, i.e. $T\\lesssim100$ MeV. As $T$ increase over $T\\approx100$ MeV, the curve for $\\kappa$ is almost saturated as a function of $T$ in the order of $\\sim10^{-1}\\,\\mathrm{GeV}^2$, and grows with respect to $\\mu$ smoothly. At the normal nuclear-matter density $\\rho_0=0.17\\,\\mathrm{fm}^{-3}$, $\\kappa$ shows its maximum $6.22\\,\\mathrm{GeV}^2$ at $T\\approx10$ MeV, then decreases exponentially down to $\\kappa\\approx0.2\\,\\mathrm{GeV}^2$. We also compute the ratio of $\\kappa$ and the entropy density, i.e. $\\kappa/s$ as a function of $(\\mu,T)$ which is a monotonically decreasing function for a wide range of $T$, then approaches a lower bound at very high $T$: $\\kappa/s_\\mathrm{min}\\gtrsim0.3\\,\\mathrm{GeV}^{-1}$ in the vicinity of $\\mu=0$.

Seung-il Nam

2015-03-04T23:59:59.000Z

288

Effect of metallic coatings on the thermal contact conductance of turned surfaces  

E-Print Network [OSTI]

area. . IInfortunately this is not always possible, due to design or load restrictions In situations where the applied load is limited. the thermal contact resistance can be reduced by introducing a material at the interface that is relatively sof... materials on thermal contact resistance both analytically and experimen- tally for a. fixed geometry and material. In the analytical portion, the approximate relative reduction of the thermal contact resistance due to plating was described as ~plating (u...

Kang, Tik Kwie

2012-06-07T23:59:59.000Z

289

Thermal transport in CO2 laser irradiated fused silica: in situ measurements and analysis  

SciTech Connect (OSTI)

In situ spatial and temporal temperature measurements of pristine fused silica surfaces heated with a 10.6 {micro}m CO{sub 2} laser were obtained using an infrared radiation thermometer based on a Mercury Cadmium Telluride (MCT) camera. Laser spot sizes ranged from 250 {micro}m to 1000 {micro}m diameter with peak axial irradiance levels of 0.13 to 16 kW/cm{sup 2}. For temperatures below 2800K, the measured steady-state surface temperature is observed to rise linearly with both increasing beam size and incident laser irradiance. The effective thermal conductivity estimated over this range was approximately 2W/mK, in good agreement with classical calculations based on phonon heat capacities. Similarly, time-dependent temperature measurements up to 2000K yielded thermal diffusivity values which were close to reported values of 7 x 10{sup -7} m{sup 2}/s. Above {approx}2800K, the fused silica surface temperature asymptotically approaches 3100K as laser power is further increased, consistent with the onset of evaporative heat losses near the silica boiling point. These results show that in the laser heating regime studied here, the T{sup 3} temperature dependent thermal conductivity due to radiation transport can be neglected, but at temperatures above 2800K heat transport due to evaporation must be considered. The thermal transport in fused silica up to 2800K, over a range of conditions, can then be adequately described by a linear diffusive heat equation assuming constant thermal properties.

Yang, S T; Matthews, M J; Elhadj, S; Draggoo, V G; Bisson, S E

2009-07-07T23:59:59.000Z

290

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

DOE Patents [OSTI]

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

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

2010-03-02T23:59:59.000Z

291

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

292

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

E-Print Network [OSTI]

analyzed a built-in, storage-type water heater containing astorage and thermal protection that can operate with PCM technology. Among them are building insulators, water heaters,

Roshandell, Melina

2013-01-01T23:59:59.000Z

293

Critical evaluation of anomalous thermal conductivity and convective heat transfer enhancement in nanofluids  

E-Print Network [OSTI]

While robust progress has been made towards the practical use of nanofluids, uncertainties remain concerning the fundamental effects of nanoparticles on key thermo-physical properties. Nanofluids have higher thermal ...

Prabhat, Naveen

2010-01-01T23:59:59.000Z

294

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

E-Print Network [OSTI]

International Conference on Gas Hydrates, Trondheim, Norway,Challenges for the future/gas hydrates, NYAS 912, 304, 2000.C. , Thermal state of the gas hydrate reservoir, natural gas

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

2006-01-01T23:59:59.000Z

295

Interplay of point defects, biaxial strain, and thermal conductivity in homoepitaxial SrTiO{sub 3} thin films  

SciTech Connect (OSTI)

Separating out effects of point defects and lattice strain on thermal conductivity is essential for improvement of thermoelectric properties of SrTiO{sub 3}. We study relations between defects generated during deposition, induced lattice strain, and their impact on thermal conductivity {kappa} in homoepitaxial SrTiO{sub 3} films prepared by ion-beam sputtering. Lowering the deposition temperature gives rise to lattice expansion by enhancement of point defect density which increases the hardness of the films. Due to a fully coherent substrate-film interface, the lattice misfit induces a large biaxial strain. However, we can show that the temperature dependence of {kappa} is mainly sensitive on the defect concentration.

Wiedigen, S.; Kramer, T.; Knorr, I.; Nee, N.; Hoffmann, J.; Volkert, C. A.; Jooss, Ch. [University of Goettingen, Institute of Materials Physics, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Feuchter, M.; Kamlah, M. [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

2012-02-06T23:59:59.000Z

296

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.

297

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.

298

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

SciTech Connect (OSTI)

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

Vu, B.T.V.

1994-02-01T23:59:59.000Z

299

ANALYTIC CRITERIA FOR THE MECHANICAL AND THERMAL STABILITY OF MAGNETIC STARS WITH FINITE ELECTRICAL CONDUCTIVITY  

E-Print Network [OSTI]

ANALYTIC CRITERIA FOR THE MECHANICAL AND THERMAL STABILITY OF MAGNETIC STARS WITH FINITE ELECTRICAL in the envelope. This physical complication also affects the interpretation of the RR Lyrae stars and other cool stars, the destabilized envelope is mostly radiative and convection probably plays only a small role

300

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

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

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...

302

The thermally stimulated conductivity in amorphous thin film As?Se?  

E-Print Network [OSTI]

Voltage (Temperature vs. Time) 21 Block Diagrams of the Temperature Control Systems 23 II-8 Parabolic Reference Voltage (Voltage vs. Time) II-9 System Heating Curves Using the Heater Control System (Temper'ature vs. Time) 25 II-10 Block Diagram.... 10 /Temperature) 32 III-3 Conductivity as Function of Temperature for the TSC Experiment (Conductivity vs. Temperature) I II 4 Carrier Concentration as Function of Temperature for TSC (Carrier Concentration vs. Temperature) 35 LIST OF SYNBOLS...

Bryant, John Duffie

1972-01-01T23:59:59.000Z

303

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

E-Print Network [OSTI]

EFFECT OF ELECTRODE CONFIGURATION AND ELECTRONIC CONDUCTIVITY ON CURRENT DENSITY DISTRIBUTION MEASUREMENTS IN PEM FUEL CELLS by Dilip Natarajan and Trung Van Nguyen* Department of Chemical and Petroleum Engineering University of Kansas... words: PEM fuel cells, conventional gas distributor, current density distribution, segmented electrode, mathematical modeling * Author to whom correspondence should be addressed ABSTRACT Current density and potential distribution measurements...

Natarajan, Dilip; Nguyen, Trung Van

2004-09-03T23:59:59.000Z

304

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

305

Self-normalized photothermal technique for accurate thermal diffusivity measurements in thin metal layers  

E-Print Network [OSTI]

Self-normalized photothermal technique for accurate thermal diffusivity measurements in thin metal method for measuring thermal diffusivity of thin metal layers has been implemented using two experimental of this method, simple experimental criteria have been developed to ascertain that a purely thermal-diffusion

Mandelis, Andreas

306

Self-consistent photothermal techniques: Application for measuring thermal diffusivity in vegetable oils  

E-Print Network [OSTI]

Self-consistent photothermal techniques: Application for measuring thermal diffusivity in vegetable of vegetable oils. The thermal diffusivity of six commercial vegetable oils olive, corn, soybean, canola in terms of thermal diffusivity was shown. The high measurement precision of the TWRC highlights

Mandelis, Andreas

307

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.

308

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

309

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

E-Print Network [OSTI]

upstream of the EarthÃ?s bow shock. The WIND/WAVES thermal noise receiver was specially designed to measureSolar wind electron density and temperature over solar cycle 23: Thermal noise measurements on Wind the in situ plasma thermal noise spectra, from which the electron density and temperature can be accurately

California at Berkeley, University of

310

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

SciTech Connect (OSTI)

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

Huang, Hai; Plummer, Mitchell; Podgorney, Robert

2013-02-01T23:59:59.000Z

311

Thermal conductance of the junction between single-walled carbon nanotubes  

E-Print Network [OSTI]

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

McGaughey, Alan

312

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

313

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

314

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

315

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

E-Print Network [OSTI]

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

Sadasivam, Sridhar; Fisher, Timothy S

2015-01-01T23:59:59.000Z

316

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

E-Print Network [OSTI]

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

Gore, David Eugene

2012-06-07T23:59:59.000Z

317

Electrical conductivity and charge diffusion in thermal QCD from the lattice  

E-Print Network [OSTI]

We present a lattice QCD calculation of the charge diffusion coefficient, the electrical conductivity and various susceptibilities of conserved charges, for a range of temperatures below and above the deconfinement crossover. The calculations include the contributions from up, down and strange quarks. We find that the diffusion coefficient is of the order of 1/(2\\pi T) and has a dip around the crossover temperature. Our results are obtained with lattice simulations containing 2+1 dynamical flavours on anisotropic lattices. The Maximum Entropy Method is used to construct spectral functions from correlators of the conserved vector current.

Gert Aarts; Chris Allton; Alessandro Amato; Pietro Giudice; Simon Hands; Jon-Ivar Skullerud

2015-02-12T23:59:59.000Z

318

Thermal conductivity control by oxygen defect concentration modification in reducible oxides: The case of Pr{sub 0.1}Ce{sub 0.9}O{sub 2??} thin films  

SciTech Connect (OSTI)

We demonstrate the impact on thermal conductivity of varying the concentration of oxygen vacancies and reduced cations in Pr{sub 0.1}Ce{sub 0.9}O{sub 2??} thin films prepared by pulsed laser deposition. The oxygen vacancy concentration is controlled by varying the oxygen partial pressure between 1?×?10{sup ?4} and 1?atm at 650??°C. Corresponding changes in the oxygen non-stoichiometry (?) are monitored by detecting the lattice parameters of the films with high-resolution X-ray diffraction, while the thermal properties are characterized by time-domain thermoreflectance measurements. The films are shown to exhibit a variation in oxygen vacancy content, and in the Pr{sup 3+}/Pr{sup 4+} ratio, corresponding to changes in ? from 0.0027 to 0.0364, leading to a reduction in the thermal conductivity from k?=?6.62?±?0.61 to 3.82?±?0.51?W/m-K, respectively. These values agree well with those predicted by the Callaway and von Baeyer model for thermal conductivity in the presence of point imperfections. These results demonstrate the capability of controlling thermal conductivity via control of anion and cation defect concentrations in a given reducible oxide.

Luckyanova, Maria N.; Chen, Gang, E-mail: gchen2@mit.edu, E-mail: byildiz@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Chen, Di; Tuller, Harry L. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ma, Wen; Yildiz, Bilge, E-mail: gchen2@mit.edu, E-mail: byildiz@mit.edu [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2014-02-10T23:59:59.000Z

319

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

320

Simultaneous measurement of thermal lens and temperature map in ytterbium-doped fluoride crystals  

E-Print Network [OSTI]

characterization of temperature map and thermal lensing in Yb3+ :CaF2 and Yb3+ :SrF2 crystals under high-power with or without laser operation. We notice that all TL dioptric powers (Dth) are negative. Since the thermal lens focal length (fth) is inversely proportional to Dth, the measured thermal lenses are divergent for both

Paris-Sud XI, Université de

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

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

322

M. Bahrami ENSC 388 (F09) Steady Conduction Heat Transfer 1 Steady Heat Conduction  

E-Print Network [OSTI]

of the material. In the limiting case where x0, the equation above reduces to the differential form: W dx dT k is the only energy interaction; the energy balance for the wall can be expressed: dt dE QQ wall outin). Thermal Conductivity Thermal conductivity k [W/mK] is a measure of a material's ability to conduct heat

Bahrami, Majid

323

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

SciTech Connect (OSTI)

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

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

1996-12-27T23:59:59.000Z

324

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

325

Advancing reactive tracer methods for measuring thermal evolution...  

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

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...

326

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

SciTech Connect (OSTI)

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

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

2014-04-14T23:59:59.000Z

327

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

E-Print Network [OSTI]

and this broadened our insight into the problems encountered with thermal management materials. As a result, we for Thermal Management: Key issues: Thermal management Macrocyclic oligomers with ultra-low melt viscosity PBT (CBT) oligomers for thermal management. We also acknowledge the support of Cool Polymers in Warwick, RI

Harmon, Julie P.

328

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

329

Cylindrical thermal contact conductance  

E-Print Network [OSTI]

of superconducting wires, tension-wound finned tubes, and large diameter pipes. Thick cylindrical shells (including solid composite cylinders) may occur in such applications as nuclear fuel rods and composite pipes. Cylindrical joints behave differently than flat...

Ayers, George Harold

2004-09-30T23:59:59.000Z

330

Experimental Development and Demonstration of Ultrasonic Measurement Diagnostics for Sodium Fast Reactor Thermal-hydraulics  

SciTech Connect (OSTI)

This research project will address some of the principal technology issues related to sodium-cooled fast reactors (SFR), primarily the development and demonstration of ultrasonic measurement diagnostics linked to effective thermal convective sensing under normatl and off-normal conditions. Sodium is well-suited as a heat transfer medium for the SFR. However, because it is chemically reactive and optically opaque, it presents engineering accessibility constraints relative to operations and maintenance (O&M) and in-service inspection (ISI) technologies that are currently used for light water reactors. Thus, there are limited sensing options for conducting thermohydraulic measurements under normal conditions and off-normal events (maintenance, unanticipated events). Acoustic methods, primarily ultrasonics, are a key measurement technology with applications in non-destructive testing, component imaging, thermometry, and velocimetry. THis project would have yielded a better quantitative and qualitative understanding of the thermohydraulic condition of solium under varied flow conditions. THe scope of work will evaluate and demonstrate ultrasonic technologies and define instrumentation options for the SFR.

Tokuhiro, Akira; Jones, Byron

2013-09-13T23:59:59.000Z

331

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

2011-11-23T23:59:59.000Z

332

Power Handling of the Bulk Tungsten Divertor Row at JET: First Measurements and Comparison to the GTM Thermal Model  

E-Print Network [OSTI]

Power Handling of the Bulk Tungsten Divertor Row at JET: First Measurements and Comparison to the GTM Thermal Model

333

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

334

An apparatus for the measurement of thermal conductivity of liquid neon  

E-Print Network [OSTI]

past the max1mum recommended storage temperature of 100 C. The hot plate, Pl, and guard ring, P2, are heated. by nicrome heater wires, whose respective resistances are 50 ohms and. 150 ohms. An additional heater of 5 ohms was placed near the cupro-nickel.... to the heater. They were coiled around the top of the guard. ring once before being soldered to the number 36 copper wires leading to the top plate. The number 36 wires go to the top plate by means of a 1/8 in. cupro-nickel tube and were sealed from...

Jensen, Jerald Norman

1967-01-01T23:59:59.000Z

335

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

E-Print Network [OSTI]

. INTRODUCTION The Helium Cooled Pebble Bed (HCPB) blanket is a typical example of the solid breeder blanket. The solid breeder blankets, such as the HCPB, feature shallow lithium ceramic pebble beds which are more beds is needed for the R&D of the solid breeder blanket; therefore the objective of this study

Abdou, Mohamed

336

Journal of Materials Processing Technology 181 (2007) 206212 Experimental measurements of the effective thermal conductivity  

E-Print Network [OSTI]

selected as tritium breeders in many designs of fusion blanket. Lithium ceramic breeding blan- ket&D. In the breeding blanket, lithium ceramics are used as tritium breeders and beryl- lium is used for neutron for the tritium breeders in a fusion blanket are sintered block and pebble bed. The sintered blocks have some

Abdou, Mohamed

2007-01-01T23:59:59.000Z

337

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

338

Measuring transient high temperature thermal phenomena in hostile environment  

SciTech Connect (OSTI)

The design of equipment for measuring temperature and strain in a rapidly heated and pressurized cylinder of stainless steel is discussed. Simultaneous cinematography of the full circumference of the cylinder without interference with temperature and strain measurements is also illustrated. The integrated system uses a reflective chamber for the sample and requires careful consideration of the spectral energy distribution utilized by each instrument.

Brenden, B.B.; Hartman, J.S.; Reich, F.R.

1980-01-01T23:59:59.000Z

339

Measurement of the thermal neutron capture cross section of {sup 180}W  

SciTech Connect (OSTI)

We measured the thermal neutron capture cross section for the {sup 180}W nucleus. There is only one previous measurement with regard to this cross section, and it yielded a value of 30 -100%+300% b. To determine whether {sup 181}W is an appropriate low energy neutrino source, the thermal neutron capture cross section should be measured more precisely to estimate the production rate of {sup 181}W inside a nuclear reactor. We measured the cross section of {sup 180}W using a natural tungsten foil and obtained a value of 22.6{+-}1.7 b.

Kang, W. G.; Kim, Y. D.; Lee, J. I.; Hahn, I. S.; Kim, A. R.; Kim, H. J. [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of); Department of Science Education, Ewha Woman's University, Seoul 120-750 (Korea, Republic of); Physics Department, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

2007-12-15T23:59:59.000Z

340

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 (OSTI)

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

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

Te (R,t) Measurements using Electron Bernstein Wave Thermal Emission on NSTX  

SciTech Connect (OSTI)

The National Spherical Torus Experiment (NSTX) routinely studies overdense plasmas with ne of (1–5) X 1019 m-3 and total magnetic field of <0.6 T, so that the first several electron cyclotron harmonics are overdense. The electrostatic electron Bernstein wave (EBW) can propagate in overdense plasmas, exhibits strong absorption, and is thermally emitted at electron cyclotron harmonics. These properties allow thermal EBW emission to be used for local Te measurement. A significant upgrade to the previous NSTX EBW emission diagnostic to measure thermal EBW emission via the oblique B-X-O mode conversion process has been completed. The new EBW diagnostic consists of two remotely steerable, quad-ridged horn antennas, each of which is coupled to a dual channel radiometer. Fundamental (8–18 GHz) and second and third harmonic (18–40 GHz) thermal EBW emission and polarization measurements can be obtained simultaneously.

Diem, S J; Efthimion, P C; LeBlanc, B P; Carter, M; Caughman, J; Wilgen, J B; Harvey, R W; Preinhaelter, J; Urban, J

2006-06-09T23:59:59.000Z

342

Measurement of volume resistivity/conductivity of metallic alloy in inhibited seawater by optical interferometry techniques  

SciTech Connect (OSTI)

Optical interferometry techniques were used for the first time to measure the volume resistivity/conductivity of carbon steel samples in seawater with different concentrations of a corrosion inhibitor. In this investigation, the real-time holographic interferometry was carried out to measure the thickness of anodic dissolved layer or the total thickness, U{sub total}, of formed oxide layer of carbon steel samples during the alternating current (ac) impedance of the samples in blank seawater and in 5-20 ppm TROS C-70 inhibited seawater, respectively. In addition, a mathematical model was derived in order to correlate between the ac impedance (resistance) and the surface (orthogonal) displacement of the surface of the samples in solutions. In other words, a proportionality constant [resistivity ({rho}) or conductivity ({sigma})= 1/{rho}] between the determined ac impedance [by electrochemical impedance spectroscopy (EIS) technique] and the orthogonal displacement (by the optical interferometry techniques) was obtained. The value of the resistivity of the carbon steel sample in the blank seawater was found similar to the value of the resistivity of the carbon steel sample air, around 1 x 10{sup -5}{Omega} cm. On the contrary, the measured values of the resistivity of the carbon steel samples were 1.85 x 10{sup 7}, 3.35 x 10{sup 7}, and 1.7 x 10{sup 7}{Omega} cm in 5, 10, and 20 ppm TROS C-70 inhibited seawater solutions, respectively. Furthermore, the determined value range of {rho} of the formed oxide layers, from 1.7 x 10{sup 7} to 3.35 x 10{sup 7}{Omega} cm, is found in a reasonable agreement with the one found in literature for the Fe oxide-hydroxides, i.e., goethite ({alpha}-FeOOH) and for the lepidocrocite ({gamma}-FeOOH), 1 x 10{sup 9}{Omega} cm. The {rho} value of the Fe oxide-hydroxides, 1 x 10{sup 9}{Omega} cm, was found slightly higher than the {rho} value range of the formed oxide layer of the present study. This is because the former value was determined by a dc method rather than by an electromagnetic method, i.e., holographic interferometry with applications of EIS, i.e., ac method. As a result, erroneous measurements were recorded due to the introduction of heat to Fe oxide-hydroxides.

Habib, K. [Materials Science Laboratory, Department of Advanced Systems KISR, P.O. Box 24885, SAFAT 13109 (Kuwait)

2011-03-15T23:59:59.000Z

343

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

344

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

345

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

346

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

E-Print Network [OSTI]

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

Gieseler, Udo D. J.

347

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

SciTech Connect (OSTI)

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

348

Bures distance as a measure of entanglement for two-mode squeezed thermal states  

SciTech Connect (OSTI)

We propose a reliable entanglement measure for a two-mode squeezed thermal state of the quantum electromagnetic field in terms of its Bures distance to the set of all separable states of the same kind. The requisite fidelity of a pair of two-mode squeezed thermal states is exactly evaluated. By applying the Peres-Simon criterion of separability, we find the closest separable state. This enables us to establish an insightful expression of the amount of entanglement. We also derive the relative entropy of a two-mode squeezed thermal state with respect to another one. This quantity is exploited in the pure-state case by undertaking a similar approximation for the entropic entanglement of a two-mode squeezed vacuum state. Comparison with previous work lends support to our approach that replaces the reference set of all separable Gaussian states by its subset consisting only of the squeezed thermal ones.

Marian, Paulina [Institute for Theoretical Atomic, Molecular and Optical Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Department of Chemistry, University of Bucharest, Boulevard Regina Elisabeta 4-12, R-030018 Bucharest (Romania); Marian, Tudor A. [Institute for Theoretical Atomic, Molecular and Optical Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Bucharest, P.O. Box MG-11, R-077125 Bucharest-Magurele (Romania); Scutaru, Horia [Center for Advanced Studies in Physics of the Romanian Academy, Calea 13 Septembrie 13, R-050711 Bucharest (Romania)

2003-12-01T23:59:59.000Z

349

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

350

A NEW MEASUREMENT STRATEGY FOR in situ TESTING OF WALL THERMAL PERFORMANCE  

E-Print Network [OSTI]

conservation, Dynamic thermal envelope thermal performanceTHERHAL TEST UNIT The envelope thermal test unit (ETTU) is athe thermal resistance of building envelope systems through

Condon, P.E.

2011-01-01T23:59:59.000Z

351

Cross-plane lattice and electronic thermal conductivities of ErAs:InGaAs/InGaAlAs superlattices  

E-Print Network [OSTI]

of thermoelectric energy conversion devices depends on the thermoelectric figure of merit ZT of a material, which the electronic thermal con- ductivity of thermoelectric materials is proportional to their electrical Joshua M. O. Zide and Arthur C. Gossard Department of Materials, University of California, Santa Barbara

352

Laboratory evaluation of the constant rate of strain and constant head techniques for measurement of the hydraulic conductivity of fine grained soils  

E-Print Network [OSTI]

This thesis evaluates the constant rate of strain and constant head techniques for measurement of the hydraulic conductivity of fine grained soils. A laboratory program compares hydraulic conductivity measurements made ...

Adams, Amy Lynn

2011-01-01T23:59:59.000Z

353

A three dimensional simulation of a thermal experiment conducted on an accelerator driven system target model concept  

E-Print Network [OSTI]

dynamics (CFD). The benchmark for the model comparison is an experiment conducted by the Institute of Physics and Power Engineering on one particular ATW system concept. The experimenters used thermocouples to determine the temperature profile...

Pratt, Preston Persley

2003-01-01T23:59:59.000Z

354

Thermal measurements of active semiconductor micro-structures acquired through the substrate using near IR thermoreflectance  

E-Print Network [OSTI]

, which precludes the use of typical surface thermal characterization techniques. A near infrared microscopy (SThM), or optical techniques such as infrared (IR) microscopy, or thermoreflectance to be able to measure the heating of devices in flip chip bonded integrated circuit's (IC) and other

355

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

356

Thermal Conductivity of Ordered Mesoporous Titania Films Made from Nanocrystalline Building Blocks and Sol-Gel Reagents  

E-Print Network [OSTI]

significant attention due to their wide range of applications. They have been used in dye-sensitized solar cells for their wide band gap semiconductor properties.1 They have also been considered for solid oxide fuel cells as high proton conductivity porous exchange membranes.2 Mesoporous TiO2 is also a very

Pilon, Laurent

357

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target  

SciTech Connect (OSTI)

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

Dubey, P. K., E-mail: premkdubey@gmail.com; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar [Acoustics, Ultrasonics, Vibration Standards and Electronics Instrumentation Cell, CSIR–National Physical Laboratory, New Delhi 110012 (India)

2014-05-15T23:59:59.000Z

358

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

E-Print Network [OSTI]

Description: The Envelope Thermal Test Unit (submitted forCross-sectional view of Envelope Thermal Test Unit blanketmeasurement prototype, the Envelope Thermal Test Unit,12 and

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

2008-01-01T23:59:59.000Z

359

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

SciTech Connect (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.

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

360

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.


361

Calonne, N., F. Flin, S. Morin, B. Lesaffre, S. Rolland du Roscoat, and C. Geindreau (2011), Numerical and experimental investigations of the effective thermal conductivity of snow, Geophys. Res. Lett., doi:10.1029/2011GL049234.  

E-Print Network [OSTI]

., doi:10.1029/2011GL049234. - 1 - Numerical and Experimental Investigations of the Effective Thermal. Res. Lett., doi:10.1029/2011GL049234. - 2 - Table of Contents and General Information Table investigations of the effective thermal conductivity of snow, Geophys. Res. Lett., doi:10.1029/2011GL049234. - 3

Ribes, Aurélien

362

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

363

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

364

TRANSPORT INVOLVING CONDUCTING FIBERS IN A NON-CONDUCTING MATRIX  

E-Print Network [OSTI]

to sev- eral applications including flexible thin-film transistors, PEM fuel cells, and direct energy, particularly Peltier devices, high electrical conductivity and low thermal conductivity are preferred

Walker, D. Greg

365

New contactless method for thermal diffusivity measurements using modulated photothermal radiometry  

SciTech Connect (OSTI)

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

366

Measurement of delayed-neutron yield from {sup 237}Np fission induced by thermal neutrons  

SciTech Connect (OSTI)

The delayed-neutron yield from thermal-neutron-induced fission of the {sup 237}Np nucleus was measured using a sample periodically exposed to a pulsed neutron beam with subsequent detection of neutrons during the time intervals between pulses. The experiment was realized on an Isomer-M setup mounted in the IBR-2 pulsed reactor channel equipped with a mirror neutron guide. The setup and the experimental procedure are described, the background sources are thoroughly analyzed, and the experimental data are presented. The total delayed-neutron yield from {sup 237}Np fission induced by thermal neutrons is {nu}{sub d} = 0.0110 {+-} 0.0009. This study was performed at the Frank Laboratory of Neutron Physics (JINR, Dubna)

Gundorin, N. A.; Zhdanova, K. V.; Zhuchko, V. E.; Pikelner, L. B., E-mail: plb@nf.jinr.ru; Rebrova, N. V.; Salamatin, I. M.; Smirnov, V. I.; Furman, V. I. [Joint Institute for Nuclear Research (Russian Federation)

2007-06-15T23:59:59.000Z

367

Kinetic Monte Carlo Simulations and Molecular Conductance Measurements of the Bacterial Decaheme Cytochrome MtrF  

SciTech Connect (OSTI)

Microorganisms overcome the considerable hurdle of respiring extracellular solid substrates by deploying large multiheme cytochrome complexes that form 20 nanometer conduits to traffic electrons through the periplasm and across the cellular outer membrane. Here we report the first kinetic Monte Carlo simulations and single-molecule scanning tunneling microscopy (STM) measurements of the Shewanella oneidensis MR-1 outer membrane decaheme cytochrome MtrF, which can perform the final electron transfer step from cells to minerals and microbial fuel cell anodes. We find that the calculated electron transport rate through MtrF is consistent with previously reported in vitro measurements of the Shewanella Mtr complex, as well as in vivo respiration rates on electrode surfaces assuming a reasonable (experimentally verified) coverage of cytochromes on the cell surface. The simulations also reveal a rich phase diagram in the overall electron occupation density of the hemes as a function of electron injection and ejection rates. Single molecule tunneling spectroscopy confirms MtrF's ability to mediate electron transport between an STM tip and an underlying Au(111) surface, but at rates higher than expected from previously calculated heme-heme electron transfer rates for solvated molecules.

Byun, H. S.; Pirbadian, S.; Nakano, Aiichiro; Shi, Liang; El-Naggar, Mohamed Y.

2014-09-05T23:59:59.000Z

368

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

SciTech Connect (OSTI)

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

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

2014-05-07T23:59:59.000Z

369

Futurestock'2003 9 International Conference on Thermal Energy Storage, Warsaw, POLAND  

E-Print Network [OSTI]

is also needed when designing a BTES (Borehole Thermal Energy Storage) system. The ground thermal381 Futurestock'2003 9 th International Conference on Thermal Energy Storage, Warsaw, POLAND, BTES, TED-measurement ABSTRACT The thermal conductivity of the ground and thermal resistance

370

An Information-Theoretic Measure of Uncertainty due to Quantum and Thermal Fluctuations  

E-Print Network [OSTI]

We study an information-theoretic measure of uncertainty for quantum systems. It is the Shannon information $I$ of the phase space probability distribution $\\la z | \\rho | z \\ra $, where $|z \\ra $ are coherent states, and $\\rho$ is the density matrix. The uncertainty principle is expressed in this measure as $I \\ge 1$. For a harmonic oscillator in a thermal state, $I$ coincides with von Neumann entropy, $- \\Tr(\\rho \\ln \\rho)$, in the high-temperature regime, but unlike entropy, it is non-zero at zero temperature. It therefore supplies a non-trivial measure of uncertainty due to both quantum and thermal fluctuations. We study $I$ as a function of time for a class of non-equilibrium quantum systems consisting of a distinguished system coupled to a heat bath. We derive an evolution equation for $I$. For the harmonic oscillator, in the Fokker-Planck regime, we show that $I$ increases monotonically. For more general Hamiltonians, $I$ settles down to monotonic increase in the long run, but may suffer an initial decrease for certain initial states that undergo ``reassembly'' (the opposite of quantum spreading). Our main result is to prove, for linear systems, that $I$ at each moment of time has a lower bound $I_t^{min}$, over all possible initial states. This bound is a generalization of the uncertainty principle to include thermal fluctuations in non-equilibrium systems, and represents the least amount of uncertainty the system must suffer after evolution in the presence of an environment for time $t$.

Arlen Anderson; Jonathan J. Halliwell

1993-04-28T23:59:59.000Z

371

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

SciTech Connect (OSTI)

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

372

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

373

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

E-Print Network [OSTI]

March 30-April THE ENVELOPE THERMAL TEST UNIT (ETTU): FIELDFigure 1. Schematic of Envelope Thermal Test Unit (cross-the dvnami c thermal propert i es of envelope c~ponents. The

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

2008-01-01T23:59:59.000Z

374

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

E-Print Network [OSTI]

March 30-April THE ENVELOPE THERMAL TEST UNIT (ETTU): FIELDFigure 1. Schematic of Envelope Thermal Test Unit (cross-the dvnami c thermal propert i es of envelope c~ponents. The

Adams, J.W.

2010-01-01T23:59:59.000Z

375

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

376

ELECTRICAL CONDUCTIVITY AND TRANSFERENCE NUMBER MEASUREMENTS OF FeO -CaO -MgO -SiO2 MELTS  

E-Print Network [OSTI]

Joule heating of the electrolyte is central to establishing the thermal balance of the reactor. Molten in proportion to the concentration of FeO. Keywords: oxygen generation, electrical conductivity, transference is electric power and this, presumably, can be generated either photovoltaically or by nuclear fission

Sadoway, Donald Robert

377

Impact of parasitic thermal effects on thermoelectric property measurements by Harman method  

SciTech Connect (OSTI)

Harman method is a rapid and simple technique to measure thermoelectric properties. However, its validity has been often questioned due to the over-simplified assumptions that this method relies on. Here, we quantitatively investigate the influence of the previously ignored parasitic thermal effects on the Harman method and develop a method to determine an intrinsic ZT. We expand the original Harman relation with three extra terms: heat losses via both the lead wires and radiation, and Joule heating within the sample. Based on the expanded Harman relation, we use differential measurement of the sample geometry to measure the intrinsic ZT. To separately evaluate the parasitic terms, the measured ZTs with systematically varied sample geometries and the lead wire types are fitted to the expanded relation. A huge discrepancy (?28%) of the measured ZTs depending on the measurement configuration is observed. We are able to separately evaluate those parasitic terms. This work will help to evaluate the intrinsic thermoelectric property with Harman method by eliminating ambiguities coming from extrinsic effects.

Kwon, Beomjin, E-mail: bkwon@kist.re.kr; Baek, Seung-Hyub; Keun Kim, Seong; Kim, Jin-Sang, E-mail: jskim@kist.re.kr [Electronic Materials Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of)] [Electronic Materials Research Center, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of)

2014-04-15T23:59:59.000Z

378

Signal generation mechanisms, intracavity-gas thermal-diffusivity temperature dependence, and absolute infrared emissivity measurements  

E-Print Network [OSTI]

, Canada Received 22 September 1997; accepted for publication 8 October 1997 The operating thermal power dominance of thermal-wave radiation power transfer in the phase channel of the thermal-wave signal at large produces an ac electrical signal proportional to the energy of the standing thermal-wave pattern

Mandelis, Andreas

379

Advanced thermal imaging of composites  

SciTech Connect (OSTI)

Composite materials were studied by Scanning Thermal Conductivity Microscope (STCM) and high speed thermography. The STCM is a qualitative technique which is used to study thermal conductivity variations on a sub-micrometer scale. High speed thermography is a quantitative technique for measuring thermal diffusivity with a variable spatial resolution from centimeters down to less than 25 gm. A relative thermal conductivity contrast map was obtained from a SiC/Si3N4 continuous fiber ceramic composite using the STCM. Temperature changes of a carbon/carbon composite after a heat pulse were captured by an IR camera to generate a thermal diffusivity map of the specimen. Line profiles of the temperature distribution showed significant variations as a result of fiber orientation.

Wang, H.; Dinwiddie, R.B.

1996-06-01T23:59:59.000Z

380

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

SciTech Connect (OSTI)

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

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

Secondary fusion coupled deuteron/triton transport simulation and thermal-to-fusion neutron convertor measurement  

SciTech Connect (OSTI)

A Monte Carlo tool RSMC (Reaction Sequence Monte Carlo) was developed to simulate deuteron/triton transportation and reaction coupled problem. The 'Forced particle production' variance reduction technique was used to improve the simulation speed, which made the secondary product play a major role. The mono-energy 14 MeV fusion neutron source was employed as a validation. Then the thermal-to-fusion neutron convertor was studied with our tool. Moreover, an in-core conversion efficiency measurement experiment was performed with {sup 6}LiD and {sup 6}LiH converters. Threshold activation foils was used to indicate the fast and fusion neutron flux. Besides, two other pivotal parameters were calculated theoretically. Finally, the conversion efficiency of {sup 6}LiD is obtained as 1.97x10{sup -4}, which matches well with the theoretical result. (authors)

Wang, G. B.; Wang, K. [Department of Engineering Physics, Tsinghua University, Beijing, 100084 (China); Liu, H. G.; Li, R. D. [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China)

2013-07-01T23:59:59.000Z

382

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

SciTech Connect (OSTI)

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

383

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

384

Calonne, N., F. Flin, S. Morin, B. Lesaffre, S. Rolland du Roscoat, and C. Geindreau (2011), Numerical and experimental investigations of the effective thermal conductivity of snow, Geophys. Res. Lett., doi:10.1029/2011GL049234, in press.  

E-Print Network [OSTI]

., doi:10.1029/2011GL049234, in press. - 1 - Numerical and Experimental Investigations of the Effective, Geophys. Res. Lett., doi:10.1029/2011GL049234, in press. - 2 - Table of Contents and General Information of the effective thermal conductivity of snow, Geophys. Res. Lett., doi:10.1029/2011GL049234, in press. - 3 - List

Ribes, Aurélien

385

High-resolution thermal expansion measurements under helium-gas pressure  

SciTech Connect (OSTI)

We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K Less-Than-Or-Slanted-Equal-To T Less-Than-Or-Slanted-Equal-To 300 K and hydrostatic pressure P Less-Than-Or-Slanted-Equal-To 250 MPa. Helium ({sup 4}He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P Asymptotically-Equal-To 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu{sub 3}(CO{sub 3}){sub 2}(OH){sub 2}, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.

Manna, Rudra Sekhar; Wolf, Bernd; Souza, Mariano de; Lang, Michael [Physics Institute, Goethe University Frankfurt(M), SFB/TR49, D-60438 Frankfurt am Main (Germany)

2012-08-15T23:59:59.000Z

386

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.

387

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

SciTech Connect (OSTI)

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

388

Nanoscale thermal transport. II. 2003–2012  

SciTech Connect (OSTI)

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

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

2014-03-15T23:59:59.000Z

389

Generalizing the flash technique in the front-face configuration to measure the thermal diffusivity of semitransparent solids  

SciTech Connect (OSTI)

In this work, we have extended the front-face flash method to retrieve simultaneously the thermal diffusivity and the optical absorption coefficient of semitransparent plates. A complete theoretical model that allows calculating the front surface temperature rise of the sample has been developed. It takes into consideration additional effects, such as multiple reflections of the heating light beam inside the sample, heat losses by convection and radiation, transparency of the sample to infrared wavelengths, and heating pulse duration. Measurements performed on calibrated solids, covering a wide range of absorption coefficients (from transparent to opaque) and thermal diffusivities, validate the proposed method.

Pech-May, Nelson Wilbur [Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao (Spain); Department of Applied Physics, CINVESTAV Unidad Mérida, carretera Antigua a Progreso km6, A.P. 73 Cordemex, Mérida Yucatán 97310, México (Mexico); Mendioroz, Arantza; Salazar, Agustín, E-mail: agustin.salazar@ehu.es [Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería, Universidad del País Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao (Spain)

2014-10-15T23:59:59.000Z

390

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]

performed as a function of mechanical inplane strain levels, heating rates, and number of thermal cycles. The apparatus generated cracks related to the in-plane stresses (or strains) on plies. The design and analysis concept of the synergistic stress...

Ju, Jaehyung

2006-10-30T23:59:59.000Z

391

Ballistic thermal point contacts made of GaAs nanopillars  

SciTech Connect (OSTI)

We measure the thermal conductance of GaAs pillars that are only a few nanometers long. Our observations can be understood with a simple model, in which the pillars constitute thermal point contacts between 3D phonon reservoirs. Moreover, first measurements of the electronic transport through these pillars are presented.

Bartsch, Th.; Wetzel, A.; Sonnenberg, D.; Schmidt, M.; Heyn, Ch.; Hansen, W. [Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany)

2013-12-04T23:59:59.000Z

392

Compact and high-particle-flux thermal-lithium-beam probe system for measurement of two-dimensional electron density profile  

SciTech Connect (OSTI)

A compact and high-particle-flux thermal-lithium-beam source for two-dimensional measurement of electron density profiles has been developed. The thermal-lithium-beam oven is heated by a carbon heater. In this system, the maximum particle flux of the thermal lithium beam was ?4 × 10{sup 19} m{sup ?2} s{sup ?1} when the temperature of the thermal-lithium-beam oven was 900 K. The electron density profile was evaluated in the small tokamak device HYBTOK-II. The electron density profile was reconstructed using the thermal-lithium-beam probe data and this profile was consistent with the electron density profile measured with a Langmuir electrostatic probe. We confirm that the developed thermal-lithium-beam probe can be used to measure the two-dimensional electron density profile with high time and spatial resolutions.

Shibata, Y., E-mail: shibata.yoshihide@jaea.go.jp; Manabe, T.; Ohno, N.; Takagi, M. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Kajita, S. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Tsuchiya, H.; Morisaki, T. [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan)

2014-09-15T23:59:59.000Z

393

ABOUT THE STUDY The UNLV Center for Business and Economic Research (CBER) conducted a study to measure the economic contribution of UNLV  

E-Print Network [OSTI]

ABOUT THE STUDY The UNLV Center for Business and Economic Research (CBER) conducted a study to measure the economic contribution of UNLV to the Southern Nevada economy. The question was asked: If UNLV during fiscal year 2011. UNLV also provides economic activity in Southern Nevada through the expenditures

Hemmers, Oliver

394

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

SciTech Connect (OSTI)

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

395

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

396

JOURNAL DE PHYSIQUE Colloque C6, suppldment au no 8, Tome 39, aolit 1978, page C6-344 LAYERING AND THERMAL CONDUCTIVITY OF 4 ~ eFILMS ON UNIFORM GRAPHITE'  

E-Print Network [OSTI]

-Halsey-Hill pressure isotherm fit /5/ which assumes liquid-like film Fin. 1 : Heat capacity of 27.47 STPcc He film combined heat capacity, vapor pressure and thermal resistance measurements to cha- racterize layering and onsets of superfluidity on a highly uniform graphite substrate, UCAR-ZYX. Strong desorption heat capacity

Paris-Sud XI, Université de

397

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

398

Measurement of the thermal expansion coefficients of ferroelectric crystals by a moire interferometer  

E-Print Network [OSTI]

reserved. Keywords: Moire´ interferometry; Ferroelectric; Thermal expansion 1. Introduction Lithium niobate-phase-matched interactions [4­6]. Design of such devices requires accurate knowledge of the relevant physi- cal parameters properties, as the thermo-optic coefficients [7]. Further- more, in quasi-phase-match nonlinear processes

Arie, Ady

399

On the information content of the thermal infrared cooling rate profile from satellite instrument measurements  

E-Print Network [OSTI]

On the information content of the thermal infrared cooling rate profile from satellite instrument 2008; accepted 25 February 2008; published 13 June 2008. [1] This work investigates how remote sensing of the quantities required to calculate clear-sky cooling rate profiles propagates into cooling rate profile

Liou, K. N.

400

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 (OSTI)

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

Note: This page contains sample records for the topic "thermal conductivity measurements" from the National Library of EnergyBeta (NLEBeta).
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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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401

Validation of thermal models for a prototypical MEMS thermal actuator.  

SciTech Connect (OSTI)

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

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

2008-09-01T23:59:59.000Z

402

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

403

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

404

Thermal transport properties of grey cast irons  

SciTech Connect (OSTI)

Thermal diffusivity and thermal conductivity of grey cast iron have been measured as a function of graphite flake morphology, chemical composition, and position in a finished brake rotor. Cast iron samples used for this investigation were cut from ``step block`` castings designed to produce iron with different graphite flake morphologies resulting from different cooling rates. Samples were also machined from prototype alloys and from production brake rotors representing a variation in foundry practice. Thermal diffusivity was measured at room and elevated temperatures via the flash technique. Heat capacity of selected samples was measured with differential scanning calorimetry, and these results were used to calculate the thermal conductivity. Microstructure of the various cast iron samples was quantified by standard metallography and image analysis, and the chemical compositions were determined by optical emission spectroscopy.

Hecht, R.L. [Ford Motor Co., Dearborn, MI (United States). Ford Research Lab.; Dinwiddie, R.B.; Porter, W.D.; Wang, Hsin [Oak Ridge National Lab., TN (United States)

1996-10-01T23:59:59.000Z

405

Radiated power measurement during the thermal quench phase of a density limit disruption  

E-Print Network [OSTI]

, but is believed to conduct preferentially to the divertor plates.4,5 In future reactor-size tokamaks, where stored of highly radiating impurities usually a noble gas such as neon , either through a massive gas puff11 to affect the plasma after being triggered and are therefore not fast enough to mitigate the entire dis

California at San Diego, University of

406

Mean carrier transport properties and charge collection dynamics of single-crystal, natural type IIa diamonds from ion-induced conductivity measurements  

SciTech Connect (OSTI)

Ion-induced conductivity has been used to investigate the detector characteristics of diamond detectors. Both integrated-charge, and time-resolved current measurements were performed to examine the mean carrier transport properties of diamond and the dynamics of charge collection under highly-localized and high-density excitation conditions. The integrated-charge measurements were conducted with a standard pulse-counting system with {sup 241}Am radioactivity as the excitation source for the detectors. The time-resolved current measurements were performed using a 70 GHz random sampling oscilloscope with the detectors incorporated into high-speed microstrip transmission lines and the excitation source for these measurements was an ion beam of either 5-MeV He{sup +} or 10-MeV Si{sup 3+}. The detectors used in both experiments can be described as metal-semiconductor-metal (MSM) devices where a volume of the detector material is sandwiched between two metal plates. A charge collection model was developed to interpret the integrated-charge measurements which enabled estimation of the energy required to produce an electron-hole pair ({epsilon}{sub di}) and the mean carrier transport properties in diamond, such as carrier mobility and lifetime, and the behavior of the electrical contacts to diamond.

Han, S.S.

1993-09-01T23:59:59.000Z

407

Non-contact, Wavelet-based Measurement of Vital Signs using Thermal Imaging S. Yu. Chekmenev, H. Rara, and Aly A. Farag  

E-Print Network [OSTI]

be measured and used to assess the person's level of physical functioning. Normal ranges of vital signs vary with ECG data as the baseline measurement. Geisheimer [6] developed a Radar Vital Signs Monitor (RVSMNon-contact, Wavelet-based Measurement of Vital Signs using Thermal Imaging S. Yu. Chekmenev, H

Farag, Aly A.

408

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

409

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

410

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

411

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

SciTech Connect (OSTI)

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

412

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 to be achieved with dual-mode-Ramjet (Ramjet under Mach 6 and Scramjet beyond) because of its high specific

Paris-Sud XI, Université de

413

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

414

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

415

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

416

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

417

LDRD final report on polyphosphaacetylenes, new hybrid conducting organic-inorganic materials  

SciTech Connect (OSTI)

Thermal, electrochemical and transition metal mediated reactions of phosphaacetylene monomers were conducted in attempts to form novel polyphosphaacetylenes as a new class of potentially electrically conducting polymers. Molecular modeling was used to simulate the molecular conformations of optimized, isolated oligomers to identify the proper monomeric repeat units for highly conjugated molecules. Electrodeposition of suitable monomers led to low molecular weight oligomers. Thermal polymerization of phosphaacetylene monomers bearing aromatic substituents ed to the formation of polyhedral cage oligomers. Under metathesis polymerization conditions the phosphaacetylene monomers form unique complexes via an unprecedented sequence of intermediates which suggest that metathesis to linear oligomers is achievable. Conductivity measurements on electrodeposited oligomers indicate modest electrical conductivity.

Jamison, G.M.; Loy, D.A.; Saunders, R.S.; Alam, T.M. [Sandia National Labs., Albuquerque, NM (United States). Properties of Organic Materials Dept.

1996-06-01T23:59:59.000Z

418

Deflection Measurements of a Thermally Simulated Nuclear Core using a High-Resolution CCD-Camera  

SciTech Connect (OSTI)

Space fission systems under consideration for near-term missions all use compact, fast-spectrum reactor cores. Reactor dimensional change with increasing temperature, which affects neutron leakage, is the dominant source of reactivity feedback in these systems. Accurately measuring core dimensional changes during realistic non-nuclear testing is therefore necessary in predicting the system 'nuclear' equivalent behavior. This paper discusses one key technique being evaluated for measuring such changes. The proposed technique is to use a Charged Couple Device (CCD) sensor to obtain deformation readings of electrically heated prototypic reactor core geometry. This paper introduces a technique by which a single high spatial resolution CCD camera is used to measure core deformation in Real-Time (RT). Initial system checkout results are presented along with a discussion on how additional cameras could be used to achieve a three-dimensional deformation profile of the core during test. (authors)

Stanojev, B.J. [Marshall Space Flight Center, National Aeronautics and Space Administration, Huntsville, Al, 35812 (United States); Houts, M. [Los Alamos National Laboratory, Department of Energy, Los Alamos, NM, 87545 (United States)

2004-07-01T23:59:59.000Z

419

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

SciTech Connect (OSTI)

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

420

A pressure gauge based on gas density measurement from analysis of the thermal noise of an atomic force microscope cantilever  

SciTech Connect (OSTI)

We describe a gas-density gauge based on the analysis of the thermally-driven fluctuations of an atomic force microscope (AFM) cantilever. The fluctuations are modeled as a ring-down of a simple harmonic oscillator, which allows fitting of the resonance frequency and damping of the cantilever, which in turn yields the gas density. The pressure is obtained from the density using the known equation of state. In the range 10-220 kPa, the pressure readings from the cantilever gauge deviate by an average of only about 5% from pressure readings on a commercial gauge. The theoretical description we use to determine the pressure from the cantilever motion is based upon the continuum hypothesis, which sets a minimum pressure for our analysis. It is anticipated that the cantilever gauge could be extended to measure lower pressures given a molecular theoretical description. Alternatively, the gauge could be calibrated for use in the non-continuum range. Our measurement technique is similar to previous AFM cantilever measurements, but the analysis produces improved accuracy.

Seo, Dongjin; Ducker, William A. [Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Paul, Mark R. [Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2012-05-15T23:59:59.000Z

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.


421

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings  

DOE Patents [OSTI]

An improved method for measuring residual stress in a material is disclosed comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress. 3 figs.

Pechersky, M.J.

1999-07-06T23:59:59.000Z

422

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings  

DOE Patents [OSTI]

An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

Pechersky, Martin J. (Aiken, SC)

1999-01-01T23:59:59.000Z

423

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

424

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

425

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

426

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

427

Conduction cooling: multicrate fastbus hardware  

SciTech Connect (OSTI)

Described is a new and novel approach for cooling nuclear instrumentation modules via heat conduction. The simplicity of liquid cooled crates and ease of thermal management with conduction cooled modules are described. While this system was developed primarily for the higher power levels expected with Fastbus electronics, it has many general applications.

Makowiecki, D.; Sims, W.; Larsen, R.

1980-11-01T23:59:59.000Z

428

Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell  

SciTech Connect (OSTI)

An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

Zaug, J.M.

1997-07-01T23:59:59.000Z

429

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

SciTech Connect (OSTI)

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

430

Measurement of probe displacement to the thermal resolution limit in photonic force microscopy using a miniature quadrant photodetector  

SciTech Connect (OSTI)

A photonic force microscope comprises of an optically trapped micro-probe and a position detection system to track the motion of the probe. Signal collection for motion detection is often carried out using the backscattered light off the probe-however, this mode has problems of low S/N due to the small backscattering cross sections of the micro-probes typically used. The position sensors often used in these cases are quadrant photodetectors. To ensure maximum sensitivity of such detectors, it would help if the detector size matched with the detection beam radius after the condenser lens (which for backscattered detection would be the trapping objective itself). To suit this condition, we have used a miniature displacement sensor whose dimensions makes it ideal to work with 1:1 images of micrometer-sized trapped probes in the backscattering detection mode. The detector is based on the quadrant photo-integrated chip in the optical pick-up head of a compact disc player. Using this detector, we measured absolute displacements of an optically trapped 1.1 {mu}m probe with a resolution of {approx}10 nm for a bandwidth of 10 Hz at 95% significance without any sample or laser stabilization. We characterized our optical trap for different sized probes by measuring the power spectrum for each probe to 1% accuracy, and found that for 1.1 {mu}m diameter probes, the noise in our position measurement matched the thermal resolution limit for averaging times up to 10 ms. We also achieved a linear response range of around 385 nm with cross talk between axes {approx_equal}4% for 1.1 {mu}m diameter probes. The detector has extremely high bandwidth (few MHz) and low optical power threshold-other factors that can lead to its widespread use in photonic force microscopy.

Pal, Sambit Bikas; Haldar, Arijit; Roy, Basudev; Banerjee, Ayan [Department of Physical Sciences, IISER-Kolkata, West Bengal 741252 (India)

2012-02-15T23:59:59.000Z

431

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

432

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

Broader source: Energy.gov [DOE]

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

433

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

434

Thermal Conduction in Graphene and Graphene Multilayers  

E-Print Network [OSTI]

graphene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .graphene . . . . . . . . . . . . . . . . . . . . . . . . .image of a typical single-layer graphene (SLG) on Si/SiO 2

Ghosh, Suchismita

2009-01-01T23:59:59.000Z

435

Conductive Thermal Interaction in Evaporative Cooling Process  

E-Print Network [OSTI]

be considered. Usually the dry-bulb depression performed by an evaporative cooler depends solely on the ambient wet-bulb temperature. The cool underground water in an evaporative cooler can cause not only adiabatic evaporation but also sensible heat transfer...

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

1990-01-01T23:59:59.000Z

436

Effects of Thermal Conductivity Ratio in  

E-Print Network [OSTI]

Single jet-impingement design Dimensions similar to HEMP Constructed of C36000 brass alloy Heated on HEMP design at 10 MW/m2 Re = 7.6104 at central port Experiments: 1104

437

Conductive Polymers  

SciTech Connect (OSTI)

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

Bohnert, G.W.

2002-11-22T23:59:59.000Z

438

Thermal control structure and garment  

DOE Patents [OSTI]

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

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

2012-03-13T23:59:59.000Z

439

Electrical and thermal properties of graphite/polyaniline composites  

SciTech Connect (OSTI)

A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

Bourdo, Shawn E., E-mail: sxbourdo@ualr.edu [Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Warford, Brock A.; Viswanathan, Tito [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)] [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)

2012-12-15T23:59:59.000Z

440

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

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

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

442

Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice  

E-Print Network [OSTI]

Nonlinear Thermal Transport and Brine Convection in First Year Sea Ice M.J. McGuinness \\Lambda , H a programme recently set up to directly measure the thermal conductivity of young sea ice. An array of thermistors frozen into first­year Antarctic sea ice provides temperature against depth data, which is fitted

443

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

444

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

445

Non-destructive thermal wave method applied to study thermal properties of fast setting time endodontic cement  

SciTech Connect (OSTI)

The thermal wave method is applied for thermal properties measurement in fast endodontic cement (CER). This new formula is developed upon using Portland cement in gel and it was successfully tested in mice with good biocompatibility and stimulated mineralization. Recently, thermal expansion and setting time were measured, conferring to this material twice faster hardening than the well known Angelus Mineral trioxide aggregate (MTA) the feature of fast hardening (?7?min) and with similar thermal expansion (?12??strain/?°C). Therefore, it is important the knowledge of thermal properties like thermal diffusivity, conductivity, effusivity in order to match thermally the tissue environment upon its application in filling cavities of teeth. Photothermal radiometry technique based on Xe illumination was applied in CER disks 600 ?m thick for heating, with prepared in four particle sizes (25, 38, 45, and 53) ?m, which were added microemulsion gel with variation volumes (140, 150, 160, and 170) ?l. The behavior of the thermal diffusivity CER disks shows linear decay for increase emulsion volume, and in contrast, thermal diffusivity increases with particles sizes. Aiming to compare to MTA, thermal properties of CER were averaged to get the figure of merit for thermal diffusivity as (44.2 ± 3.6) × 10{sup ?3} cm{sup 2}/s, for thermal conductivity (228 ± 32) mW/cm K, the thermal effusivity (1.09 ± 0.06) W s{sup 0.5}/cm{sup 2} K and volume heat capacity (5.2 ± 0.7) J/cm{sup 3} K, which are in excellent agreement with results of a disk prepared from commercial MTA-Angelus (grain size < 10 ?m using 57 ?l of distilled water)

Picolloto, A. M.; Mariucci, V. V. G.; Szpak, W.; Medina, A. N.; Baesso, M. L.; Astrath, N. G. C.; Astrath, F. B. G.; Bento, A. C., E-mail: acbento@uem.br [Departamento de Física, Grupo de Espectroscopia Fotoacústica e Fototérmica, Universidade Estadual de Maringá – UEM, Av. Colombo 5790, 87020-900 Maringá, Paraná (Brazil); Santos, A. D.; Moraes, J. C. S. [Departamento de Física e Química, Universidade Estadual Paulista Júlio de Mesquita Filho – UNESP, Av. Brasil 56, 15385-000 Ilha Solteira, SP (Brazil)

2013-11-21T23:59:59.000Z

446

Multiscale thermal transport.  

SciTech Connect (OSTI)

A concurrent computational and experimental investigation of thermal transport is performed with the goal of improving understanding of, and predictive capability for, thermal transport in microdevices. The computational component involves Monte Carlo simulation of phonon transport. In these simulations, all acoustic modes are included and their properties are drawn from a realistic dispersion relation. Phonon-phonon and phonon-boundary scattering events are treated independently. A new set of phonon-phonon scattering coefficients are proposed that reflect the elimination of assumptions present in earlier analytical work from the simulation. The experimental component involves steady-state measurement of thermal conductivity on silicon films as thin as 340nm at a range of temperatures. Agreement between the experiment and simulation on single-crystal silicon thin films is excellent, Agreement for polycrystalline films is promising, but significant work remains to be done before predictions can be made confidently. Knowledge gained from these efforts was used to construct improved semiclassical models with the goal of representing microscale effects in existing macroscale codes in a computationally efficient manner.

Graham, Samuel Jr. (; .); Wong, C. C.; Piekos, Edward Stanley

2004-02-01T23:59:59.000Z

447

Article for thermal energy storage  

DOE Patents [OSTI]

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

Salyer, Ival O. (Dayton, OH)

2000-06-27T23:59:59.000Z

448

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

449

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 (OSTI)

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

450

Thermal protection apparatus  

DOE Patents [OSTI]

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

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

1984-03-20T23:59:59.000Z

451

Thermal protection apparatus  

DOE Patents [OSTI]

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

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

1985-01-01T23:59:59.000Z

452

JOURNAL DE PHYSIQUE Colloque C6, supplkment au no 8, Tome 39, aolit 1978,page C6-186 THERMAL TRANSPORT IN 3 ~ e -4 ~ e EIXTURES  

E-Print Network [OSTI]

point tricrltique, ceci en accord avec les prddictions thgoriques. Abstract.-Measurements of the thermal diffusivity ratio K~ and of the thermal conductivity ceff in the absence of mass flow are reported. While K the Clausius-Mossotti relation effects during sound velocity measurements ~ielded Article published online

Paris-Sud XI, Université de

453

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

454

Thermal Fluids  

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

Thermal Fluids The Thermal Fluids and Heat Transfer program works on thermal hydraulic reactor safety code development and experimental heat transferthermal hydraulics. The...

455

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 (OSTI)

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

456

Thermal loading study for FY 1995  

SciTech Connect (OSTI)

This report provides the results of sensitivity analyses designed to assist the test planners in focusing their in-situ measurements on parameters that appear to be important to waste isolation. Additionally, the study provides a preliminary assessment of the feasibility of certain thermal management options. A decision on thermal loading is a critical part of the scientific and engineering basis for evaluating regulatory compliance of the potential repository for waste isolation. To show, with reasonable assurance, that the natural and engineered barriers will perform adequately under expected repository conditions (thermally perturbed) will require an integrated approach based on thermal testing (laboratory, and in-situ), natural analog observations, and analytic modeling. The Office of Civilian Radioactive Waste Management needed input to assist in the planning of the thermal testing program. Additionally, designers required information on the viability of various thermal management concepts. An approximately 18-month Thermal Loading Study was conducted from March, 1994 until September 30, 1995 to address these issues. This report documents the findings of that study. 89 refs., 71 figs., 33 tabs.

NONE

1996-01-31T23:59:59.000Z

457

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

458

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

SciTech Connect (OSTI)

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

459

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

460

CONDUCTANCE OF NANOSYSTEMS WITH INTERACTION  

E-Print Network [OSTI]

-beam lithography or small metallic grains,[1] semiconductor quantum dots,[2] or a single large molecule of an atomic-size bridge that forms in the break,[3] or even measure the conductance of a single hydrogen

Ramsak, Anton

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461

Thermal boundary resistance and diffusivity measurements on thin YBa2Cu307--x films with MgO and SrTi03 substrates using the transient  

E-Print Network [OSTI]

O and SrTiOs substrates. The anisotropic YBazCu30,-, thermal diffusivity constants and the thermal boundary, are performed to obtain information on thermal diffusivity and to demonstrate the applicability of the technique the thermal diffusivity con- stants and boundary resistance in thin films of YBCO on MgO crystalline

Fayer, Michael D.

462

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

463

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

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

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

464

Systems analysis of thermal storage  

SciTech Connect (OSTI)

During FY80 analyses were conducted on thermal storage concepts for solar thermal applications. These studies include both estimates of the obtainable costs of thermal storage concepts and their worth to a user (i.e., value). Based on obtainable costs and performance, promising thermal storage concepts are being identified. A preliminary screening was completed in FY80 and a more in-depth study was initiated. Value studies are being conducted to establish cost goals. A ranking of storage concepts based on value in solar thermal electric plants was conducted for both diurnal and long duration applications. Ground mounted thermal storage concepts for a parabolic dish/Stirling systtem are also being evaluated.

Copeland, R. J.

1980-08-01T23:59:59.000Z

465

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

466

Systems analysis of thermal storage  

SciTech Connect (OSTI)

During FY 1981, analyses were conducted on thermal storage concepts for solar thermal applications. These studies include estimates of both the obtainable costs of thermal storage concepts and their worth to a user (i.e., value). Based on obtainable costs and performance, an in-depth study evaluated thermal storage concepts for water/steam, organic fluid, and gas/Brayton solar thermal receivers. Promising and nonpromising concepts were identified. A study to evaluate thermal storage concepts for a liquid metal receiver was initiated. The value of thermal storage in a solar thermal industrial process heat application was analyzed. Several advanced concepts are being studied, including ground-mounted thermal storage for parabolic dishes with Stirling engines.

Copeland, R.J.

1981-08-01T23:59:59.000Z

467

Comparison of different experimental and analytical measures of the thermal annealing response of neutron-irradiated RPV steels  

SciTech Connect (OSTI)

The thermal annealing response of several materials as indicated by Charpy transition temperature (TT) and upper-shelf energy (USE), crack initiation toughness, K{sub Jc}, predictive models, and automated-ball indentation (ABI) testing are compared. The materials investigated are representative reactor pressure vessel (RPV) steels (several welds and a plate) that were irradiated for other tasks of the Heavy-Section Steel Irradiation (HSSI) Program and are relatively well characterized in the unirradiated and irradiated conditions. They have been annealed at two temperatures, 343 and 454 C (650 and 850 F) for varying lengths of time. The correlation of the Charpy response and the fracture toughness, ABI, and the response predicted by the annealing model of Eason et al. for these conditions and materials appears to be reasonable. The USE after annealing at the temperature of 454 C appears to recover at a faster rate than the TT, and even over-recovers (i.e., the recovered USE exceeds that of the unirradiated material).

Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1997-05-01T23:59:59.000Z

468

Comparison of different experimental and analytical measures of the thermal annealing response of neutron-irradiated RPV steels  

SciTech Connect (OSTI)

The thermal annealing response of several materials as indicated by Charpy transition temperature (TT) and upper-shelf energy (USE), crack initiation toughness, K{sub Jc}, predictive models, and automated-ball indentation (ABI) testing are compared. The materials investigated are representative reactor pressure vessel (RPV) steels (several welds and a plate) that were irradiated for other tasks of the Heavy-Section Steel Irradiation (HSSI) Program and are relatively well characterized in the unirradiated and irradiated conditions. They have been annealed at two temperatures, 343 and 454 C (650 and 850 F) for varying lengths of time. The correlation of the Charpy response and the fracture toughness, ABI, and the response predicted by the annealing model of Eason et al. for these conditions and materials appears to be reasonable. The USE after annealing at the temperature of 454 C appears to recover at a faster rate than the TT, and even over-recovers (i.e., the recovered USE exceeds that of the unirradiated material).

Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1999-10-01T23:59:59.000Z

469

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

470

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

471

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

472

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

473

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

474

Thermal performance of steel-framed walls. Final report  

SciTech Connect (OSTI)

In wall construction, highly conductive members spaced along the wall, which allow higher heat transfer than that through less conductive areas, are referred to as thermal bridges. Thermal bridges in walls tend to increase heat loss and, under certain adverse conditions, can cause dust streaking (``ghosting``) on interior walls over studs due to temperature differentials, as well as condensation in and on walls. Although such adverse conditions can be easily avoided by proper thermal design of wall systems, these effects have not been well understood and thermal data has been lacking. Therefore, the present study was initiated to provide (1) a better understanding of the thermal behavior of steel-framed walls, (2) a set of R-values for typical wall constructions, and (3) information that could be used to develop improved methods of predicting R-values. An improved method for estimating R-value would allow an equitable comparison of thermal performance with other construction types and materials. This would increase the number of alternative materials for walls available to designers, thus allowing them to choose the optimum choice for construction. Twenty-three wall samples were tested in a calibrated hot box (ASTM C9761) to measure the thermal performance of steel-framed wall systems. The tests included an array of stud frame configurations, exterior sheathing and fiberglass batt insulations. Other studies have not included the use of insulating sheathing, which reduces the extent of the thermal bridges and improves total thermal performance. The purpose of the project was to provide measured R-values for commonly used steel-framed wall configurations and to improve R-value estimating methods. Test results were compared to R-value estimates using the parallel path method, the isothermal planes method and the ASHRAE Zone method. The comparison showed that the known procedures do not fully account for the three-dimensional effects created by steel framing in a wall.

Barbour, E. [NAHB Research Center, Inc., Upper Marlboro, MD (United States); Goodrow, J. [Holometrix, Inc., Bedford, MA (United States); Kosny, J.; Christian, J.E. [Oak Ridge National Lab., TN (United States)

1994-11-21T23:59:59.000Z

475

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

476

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

477

Sampling Artifacts from Conductive Silicone Tubing  

SciTech Connect (OSTI)

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

478

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

479

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

480

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

Note: This page contains sample records for the