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


1

Thermal conductivity Measurements of Kaolite  

Science Conference Proceedings (OSTI)

Testing was performed to determine the thermal conductivity of Kaolite 1600, which primarily consists of Portland cement and vermiculite. The material was made by Thermal Ceramics for refractory applications. Its combination of light weight, low density, low cost, and noncombustibility made it an attractive alternative to the materials currently used in ES-2 container for radioactive materials. Mechanical properties and energy absorption tests of the Kaolite have been conducted at the Y-12 complex. Heat transfer is also an important factor for the application of the material. The Kaolite samples are porous and trap moisture after extended storage. Thermal conductivity changes as a function of moisture content below 100 C. Thermal conductivity of the Kaolite at high temperatures (up to 700 C) are not available in the literature. There are no standard thermal conductivity values for Kaolite because each sample is somewhat different. Therefore, it is necessary to measure thermal conductivity of each type of Kaolite. Thermal conductivity measurements will help the modeling and calculation of temperatures of the ES-2 containers. This report focuses on the thermal conductivity testing effort at ORNL.

Wang, H

2003-02-21T23:59:59.000Z

2

Measuring Thermal Conductivity of Powder Insulation at Cryogenic Temperatures.  

E-Print Network (OSTI)

?? A device to measure bulk effective thermal conductivity of powder insulation at cryogenic temperatures has been designed and tested. The design consists of two… (more)

Barrios, Matthew Nicklas

2006-01-01T23:59:59.000Z

3

3 omega method for specific heat and thermal conductivity measurements  

E-Print Network (OSTI)

We present a 3 omega method for simultaneously measuring the specific heat and thermal conductivity of a rod- or filament-like specimen using a way similar to a four-probe resistance measurement. The specimen in this method needs to be electrically conductive and with a temperature-dependent resistance, for acting both as a heater to create a temperature fluctuation and as a sensor to measure its thermal response. With this method we have successfully measured the specific heat and thermal conductivity of platinum wire specimens at cryogenic temperatures, and measured those thermal quantities of tiny carbon nanotube bundles some of which are only 10^-9 g in mass.

L. Lu; W. Yi; D. L. Zhang

2002-02-06T23:59:59.000Z

4

Thermal Conductivity Measurements of Thermoelectric Films  

Science Conference Proceedings (OSTI)

... which allow solid-state conversion of thermal to electrical energy, have a ... and exhaust system, which can run either an electric motor or accessories ...

2013-03-15T23:59:59.000Z

5

VALIDATION OF A THERMAL CONDUCTIVITY MEASUREMENT SYSTEM FOR FUEL COMPACTS  

SciTech Connect

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

An Empirical Model of UO2 Thermal Conductivity Based on Laser Flash Measurements of Thermal Diffusivity  

Science Conference Proceedings (OSTI)

Thermal conductivity of irradiated fuel materials, which can be derived from measured thermal diffusivity (TD), is a key consideration in thermal performance and design of a fuel rod. However, without interpretation, the measured TD data cannot be used directly to calculate fuel temperatures during irradiation. This report provides such interpretation and presents an empirical model for the degradation of UO2 thermal conductivity with burn-up.

1998-10-07T23:59:59.000Z

7

Experimental measurements of the thermal conductivity of ash deposits: Part 1. Measurement technique  

Science Conference Proceedings (OSTI)

This paper describes a technique developed to make in situ, time-resolved measurements of the effective thermal conductivity of ash deposits formed under conditions that closely replicate those found in the convective pass of a commercial boiler. Since ash deposit thermal conductivity is thought to be strongly dependent on deposit microstructure, the technique is designed to minimize the disturbance of the natural deposit microstructure. Traditional techniques for measuring deposit thermal conductivity generally do not preserve the sample microstructure. Experiments are described that demonstrate the technique, quantify experimental uncertainty, and determine the thermal conductivity of highly porous, unsintered deposits. The average measured conductivity of loose, unsintered deposits is 0.14 {+-} 0.03 W/(m K), approximately midway between rational theoretical limits for deposit thermal conductivity.

A. L. Robinson; S. G. Buckley; N. Yang; L. L. Baxter

2000-04-01T23:59:59.000Z

8

Spatially localized measurement of thermal conductivity using a hybrid photothermal technique  

SciTech Connect

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

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.

10

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

11

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

SciTech Connect

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

Williams, Colin F.; Sass, John H.

1996-01-24T23:59:59.000Z

12

Estimation of in-situ thermal conductivities from temperature gradient measurements  

Science Conference Proceedings (OSTI)

A mathematical model has been developed to study the effect of variable thermal conductivity of the formations, and the wellbore characteristics, on the fluid temperature behavior inside the wellbore during injection or production and after shut-in. During the injection or production period the wellbore fluid temperature is controlled mainly by the fluid flow rate and the heat lost from the fluid to the formation. During the shut-in period, the fluid temperature is strongly affected by differences in the formation thermal conductivities. Based on the results of the present analysis, two methods for estimating in-situ thermal conductivity were derived. First, the line source concept is extended to estimate values of the formation thermal conductivities utilizing the fluid temperature record during the transient period of injection or production and shut-in. The second method is applied when a well is under thermal equilibrium conditions. Values of the formation thermal conductivities can also be estimated by using a continuous temperature gradient log and by measuring the thermal conductivity of the formation at a few selected wellbore locations.

Hoang, V.T.

1980-12-01T23:59:59.000Z

13

Thermal conductivity of thermal-battery insulations  

DOE Green Energy (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

14

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

Science Conference Proceedings (OSTI)

This paper describes a new design for the transient hot wire method that can obtain the thermal conductivity and thermal diffusivity of unconsolidated materials. In this method

Greg C. Glatzmaier; W. Fred Ramirez

1985-01-01T23:59:59.000Z

15

Thermally Conductive Graphite Foam  

oriented graphite planes, similar to high performance carbon fibers, which have been estimated to exhibit a thermal conductivity greater than 1700 ...

16

Thermal conductivity of aqueous foam  

Science Conference Proceedings (OSTI)

Thermal conductivity plays an important part in the response of aqueous foams used as geothermal drilling fluids. The thermal conductivity of these foams was measured at ambient conditions using the thermal conductivity probe technique. Foam densities studied were from 0.03 to 0.2 g/cm/sup 3/, corresponding to liquid volume fractions of the same magnitude. Microscopy of the foams indicated bubble sizes in the range 50 to 300 ..mu..m for nitrogen foams, and 30 to 150 ..mu..m for helium foams. Bubble shapes were observed to be polyhedral at low foam densities and spherical at the higher densities. The measured conductivity values ranged from 0.05 to 0.12 W/m-K for the foams studied. The predicted behavior in foam conductivity caused by a change in the conductivity of the discontinuous gas phase was observed using nitrogen or helium gas in the foams. Analysis of the probe response data required an interpretation using the full intergral solution to the heat conduction equation, since the thermal capacity of the foam was small relative to the thermal mass of the probe. The measurements of the thermal conductivity of the foams were influenced by experimental effects such as the probe input power, foam drainage, and the orientation of the probe and test cell. For nitrogen foams, the thermal conductivity vs liquid volume fraction was observed to fall between predictions based on the parallel ordering and Russell models for thermal conduction in heterogeneous materials.

Drotning, W.D.; Ortega, A.; Havey, P.E.

1982-05-01T23:59:59.000Z

17

Measurement of effective thermal conductivity of wheat as a function of moisture content  

Science Conference Proceedings (OSTI)

Grain drying and storage are one of the main activities of agricultural industry. Increasing energy costs have stressed the importance of calculation of heat and mass transfer in a grain bulk in order to be able to optimize drying facilities. Another limitation during drying is the preservation of grain structure and its nutritional values, Muehlbauer and Christ have shown that damage to the grain structure and grain nutritional value is dependent upon grain temperature and drying time. Therefore, proper conditions during drying and storage of cereal grains require the knowledge of the thermophysical properties of the grains. The effective thermal conductivity of two varieties of Triticum durum wheat and a wheat product, bulgur, is determined at different moisture contents and at ambient temperature by the transient lime heat source method. The moisture contents of the samples ranged from 9.17 to 38.65% wet basis and the bulk densities ranged from 675 to 827 kg/m{sup 3}. Under those conditions, the measured effective thermal conductivities ranged from 0.159 to 0.201 W/m.K. The effective thermal conductivity is found to be linearly increasing with moisture content. The results are also in good agreement with literature values.

Tavman, S. [Ege Univ., Izmir (Turkey). Food Engineering Dept.] [Ege Univ., Izmir (Turkey). Food Engineering Dept.; Tavman, I.H. [Dokuz Eyluel Univ., Izmir (Turkey). Mechanical Engineering Dept.] [Dokuz Eyluel Univ., Izmir (Turkey). Mechanical Engineering Dept.

1998-07-01T23:59:59.000Z

18

Cylindrical thermal contact conductance  

E-Print Network (OSTI)

Thermal contact conductance is highly important in a wide variety of applications, from the cooling of electronic chips to the thermal management of spacecraft. The demand for increased efficiency means that components need to withstand higher temperatures and heat transfer rates. Many situations call for contact heat transfer through nominally cylindrical interfaces, yet relatively few studies of contact conductance through cylindrical interfaces have been undertaken. This study presents a review of the experimental and theoretical investigations of the heat transfer characteristics of composite cylinders, presenting data available in open literature in comparison with relevant correlations. The present investigation presents a study of the thermal contact conductance of cylindrical interfaces. The experimental investigation of sixteen different material combinations offers an opportunity to develop predictive correlations of the contact conductance, in conjunction with an analysis of the interface pressure as a function of the thermal state of the individual cylindrical shells. Experimental results of the present study are compared with previously published conductance data and conductance models.

Ayers, George Harold

2003-08-01T23:59:59.000Z

19

Enhanced Thermal Conductivity Oxide Fuels  

SciTech Connect

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

Alvin Solomon; Shripad Revankar; J. Kevin McCoy

2006-01-17T23:59:59.000Z

20

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

E-Print Network (OSTI)

fall within ~ 10%. Heat conduction through the TCs coulda 6% difference. To eliminate heat conduction effects, otherlaw formulation of heat conduction in materials. BASIC

Louie, Brian Ming

2011-01-01T23:59:59.000Z

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


21

THERMAL CONDUCTIVITY ANALYSIS OF GASES  

DOE Patents (OSTI)

This patent describes apparatus for the quantitative analysis of a gaseous mixture at subatmospheric pressure by measurement of its thermal conductivity. A heated wire forms one leg of a bridge circuit, while the gas under test is passed about the wire at a constant rate. The bridge unbalance will be a measure of the change in composition of the gas, if compensation is made for the effect due to gas pressure change. The apparatus provides a voltage varying with fluctuations of pressure in series with the indicating device placed across the bridge, to counterbalance the voltage change caused by fluctuations in the pressure of the gaseous mixture.

Clark, W.J.

1949-06-01T23:59:59.000Z

22

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

SciTech Connect

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

23

Thermal Conduction in Graphene and Graphene Multilayers  

E-Print Network (OSTI)

1 1.2 Thermal transport atxv Introduction xii 1.1 Thermal conductivity and65 4.13 Thermal conductivity of graphene as a function of

Ghosh, Suchismita

2009-01-01T23:59:59.000Z

24

High temperature thermal conductivity measurements of UO/sub 2/ by Direct Electrical Heating. Final report. [MANTRA-III  

SciTech Connect

High temperature properties of reactor type UO/sub 2/ pellets were measured using a Direct Electrical Heating (DEH) Facility. Modifications to the experimental apparatus have been made so that successful and reproducible DEH runs may be carried out while protecting the pellets from oxidation at high temperature. X-ray diffraction measurements on the UO/sub 2/ pellets have been made before and after runs to assure that sample oxidation has not occurred. A computer code has been developed that will model the experiment using equations that describe physical properties of the material. This code allows these equations to be checked by comparing the model results to collected data. The thermal conductivity equation for UO/sub 2/ proposed by Weilbacher has been used for this analysis. By adjusting the empirical parameters in Weilbacher's equation, experimental data can be matched by the code. From the several runs analyzed, the resulting thermal conductivity equation is lambda = 1/4.79 + 0.0247T/ + 1.06 x 10/sup -3/ exp(-1.62/kT/) - 4410. exp(-3.71/kT/) where lambda is in w/cm K, k is the Boltzman constant, and T is the temperature in Kelvin.

Bassett, B

1980-10-01T23:59:59.000Z

25

Thermal conductivity modeling of building façade materials  

Science Conference Proceedings (OSTI)

An experimental research has been conducted to assess the thermo-physical properties of three building materials in both dry and moist state: beech wood, autoclaved aerated concrete and brick. The objectives of the paper envisage the measurement of the ... Keywords: building materials, contact temperature, determining method, finite element, numerical modeling, thermal conductivity

Monica Chereches; Nelu-Cristian Chereches; Catalin Popovici

2010-04-01T23:59:59.000Z

26

Invert Effective Thermal Conductivity Calculation  

SciTech Connect

The objective of this calculation is to evaluate the temperature-dependent effective thermal conductivities of a repository-emplaced invert steel set and surrounding ballast material. The scope of this calculation analyzes a ballast-material thermal conductivity range of 0.10 to 0.70 W/m {center_dot} K, a transverse beam spacing range of 0.75 to 1.50 meters, and beam compositions of A 516 carbon steel and plain carbon steel. Results from this calculation are intended to support calculations that identify waste package and repository thermal characteristics for Site Recommendation (SR). This calculation was developed by Waste Package Department (WPD) under Office of Civilian Radioactive Waste Management (OCRWM) procedure AP-3.12Q, Revision 1, ICN 0, Calculations.

M.J. Anderson; H.M. Wade; T.L. Mitchell

2000-03-17T23:59:59.000Z

27

Nanoscale thermal transport and the thermal conductance of interfaces  

E-Print Network (OSTI)

absorption depends on temperature of the nanotube · Assume heat capacity is comparable to graphite · Cooling conductance · Pump probe apparatus · Transient absorption ­ Carbon nanotubes and thermal transport at hard optical absorption of nanoparticles and nanotubes in liquid suspensions. ­ Measure the thermal relaxation

Braun, Paul

28

Electron thermal conduction in LASNEX  

SciTech Connect

This report is a transcription of hand-written notes by DM dated 29 January 1986, transcribed by SW, with some clarifying comments added and details specific to running the LASNEX code deleted. Reference to the esoteric measurement units employed in LASNEX has also been deleted by SW (hopefully, without introducing errors in the numerical constants). The report describes the physics equations only, and only of electron conduction. That is, it does not describe the numerical method, which may be finite difference or finite element treatment in space, and (usually) implicit treatment in time. It does not touch on other electron transport packages which are available, and which include suprathermal electrons, nonlocal conduction, Krook model conduction, and modifications to electron conduction by magnetic fields. Nevertheless, this model is employed for the preponderance of LASNEX simulations.

Munro, D.; Weber, S.

1994-12-16T23:59:59.000Z

29

Effect of heat treatment temperature on binder thermal conductivities  

SciTech Connect

The effect of heat treatment on the thermal conductivities of a pitch and a polyfurfuryl alcohol binder residue was investigated. Graphites specially prepared with these two binders were used for the experiments. Measured thermal conductivities were treated in terms of a two-component system, and the binder thermal conductivities were calculated. Both binder residues showed increased thermal conductivity with increased heat treatment temperature. (auth)

Wagner, P.

1975-12-01T23:59:59.000Z

30

Preliminary measurements of the thermal conductivity of rocks from LASL geothermal test holes GT-1 and GT-2  

DOE Green Energy (OSTI)

The conductivities on a number of dry rocks have been measured in an air environment. These experimental values are probably about 10 percent lower than the in situ values. Initial attempts to prepare ''wet'' rock samples (rocks saturated with water) have so far resulted in only ''damp'' rocks. Considerable effort will be required to characterize the crack system in ''solid'' rocks and to predict the probable conductivity values for in situ conditions.

Sibbitt, W.L.

1975-12-01T23:59:59.000Z

31

Enhancing Thermal Conductivity and Reducing Friction  

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

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

32

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

Science Conference Proceedings (OSTI)

A novel 3?thermal conductivitymeasurement technique called metal-coated 3? is introduced for use with liquids

Scott N. Schiffres; Jonathan A. Malen

2011-01-01T23:59:59.000Z

33

Correlation Between Thermal Conductivity and Microstructural ...  

Science Conference Proceedings (OSTI)

Characterization of MOX fuel pellets by Photothermal microscopy · Correlation Between Thermal Conductivity and Microstructural Evolutions in CeO2 Upon ...

34

An Innovative High Thermal Conductivity Fuel Design  

SciTech Connect

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

35

Increased thermal conductivity monolithic zeolite structures  

SciTech Connect

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

36

Thermal conductivity and other properties of cementitious grouts  

DOE Green Energy (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.

1998-08-01T23:59:59.000Z

37

THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS  

DOE Green Energy (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

38

High Thermal Conductivity AlN Materials  

Science Conference Proceedings (OSTI)

AlN has replaced BeO as the high thermal conductivity ceramic of choice due to the adverse health effects associated with BeO. The development of high ...

39

Raman Spectroscopy of High Thermal Conductivity AlN Ceramics ...  

Science Conference Proceedings (OSTI)

Thermal conductivity of AlN ceramics was measured by laser flash method. Raman spectroscopy was used to characterize oxygen related defects of AlN ... Transport in Co-Based Materials for Fuel Cells and Oxygen Separation Membranes.

40

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

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


41

Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films  

E-Print Network (OSTI)

K.L. Fang, “Anisotropic thermal conductivity of nanoporousmesoporous silica as a thermal isolation layer”, Ceramicsand V. Wittwer, “Some thermal and optical properties of a

Coquil, Thomas; Richman, Eric K.; Hutchinson, Neal J.; Tolbert, S H; Pilon, Laurent

2009-01-01T23:59:59.000Z

42

Thermal conduction in cosmological SPH simulations  

E-Print Network (OSTI)

Thermal conduction in the intracluster medium has been proposed as a possible heating mechanism for offsetting central cooling losses in rich clusters of galaxies. In this study, we introduce a new formalism to model conduction in a diffuse ionised plasma using smoothed particle hydrodynamics (SPH), and we implement it in the parallel TreePM/SPH-code GADGET-2. We consider only isotropic conduction and assume that magnetic suppression can be described in terms of an effective conductivity, taken as a fixed fraction of the temperature-dependent Spitzer rate. We also account for saturation effects in low-density gas. Our formulation manifestly conserves thermal energy even for individual and adaptive timesteps, and is stable in the presence of small-scale temperature noise. This allows us to evolve the thermal diffusion equation with an explicit time integration scheme along with the ordinary hydrodynamics. We use a series of simple test problems to demonstrate the robustness and accuracy of our method. We then ...

Jubelgas, M; Dolag, K

2004-01-01T23:59:59.000Z

43

Thermal conductivity of mass-graded graphene flakes  

E-Print Network (OSTI)

In this letter we investigate thermal conductions in mass-graded graphene flakes by nonequilibrium molecular dynamics simulations. It shows mass-graded graphene flakes reveal no thermal rectification effect in thermal conduction process. Dependences of thermal conductivity upon the heat fluxes and the mass gradients are studied. It is found that thermal conductivity would be dramatically decreased by increasing the mass gradients. We also discuss the influence of thermal curvatures and thermal expansions upon the thermal conduction process in mass-graded graphene flakes.

Cheh, Jigger

2011-01-01T23:59:59.000Z

44

Effects of air infiltration on the effective thermal conductivity...  

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

Effects of air infiltration on the effective thermal conductivity of internal fiberglass insulation and on the delivery of thermal capacity via ducts Title Effects of air...

45

Reduced Thermal Conductivity of Compacted Silicon Nanowires  

E-Print Network (OSTI)

alpha1=k1/(density1*cp1); %Thermal diffusivity of PMMA B1=Simon R. Phillpot, “Nanoscale Thermal Transport”, Journal of9] E.T. Swartz, R.O. Pohl, “Thermal Boundary Resistance”,

Yuen, Taylor S.

46

Conductive Thermal Interaction in Evaporative Cooling Process  

E-Print Network (OSTI)

It has long been recognized that evaporative cooling is an effective and logical substitute for mechanical cooling in hot-arid climates. This paper explores the application of evaporative coolers to the hot-humid climates using a controlled temperature of the incoming water. With exploitation of the effect of the thermal conduction between cool underground water and entering air, the performance of an evaporative cooler can be enhanced and its use in hot and moderately humid climates should also 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 between water and entering air for thermal comfort. This hybrid system outperforms the two-stage evaporative cooler without employing a complicated heat exchanger (indirect system), if the temperature of underground water is lower than the ambient wet-bulb temperature. Several areas in the southern hot-humid parts of the U.S. meet this condition.

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

1990-01-01T23:59:59.000Z

47

Ab-Initio Thermal Conductivity for Thermoelectric Nanostructured ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Energy Nanomaterials. Presentation Title, Ab-Initio Thermal Conductivity for ...

48

Thermal Conductivity and Shear Strength of K Basin Sludge  

DOE Green Energy (OSTI)

Hanford K Basin sludge contains metallic uranium and uranium oxides that will corrode, hydrate, and, consequently, generate heat and hydrogen gas during storage. Heat is generated within the K Basin sludge by radiolytic decay and the reaction of uranium metal with water. To maintain thermal stability, the sludge must be retrieved, staged, transported, and stored in systems designed to provide a rate of heat removal that prevents the temperature in the sludge from increasing beyond acceptable limits. To support the dispositioning of the sludge to T Plant, modeling and testing and analyses are being performed to predict the behavior of sludge when placed into the storage containers. Two physical properties of the sludge that are critical to the modeling and analyses efforts are thermal conductivity and the sludge shear strength (yield stress). This report provides the results of thermal conductivity and shear strength measurements performed on representative sludge samples from the K East Basin.

Poloski, Adam P. (BATTELLE (PACIFIC NW LAB)); Bredt, Paul R. (BATTELLE (PACIFIC NW LAB)); Schmidt, Andrew J. (BATTELLE (PACIFIC NW LAB)); Swoboda, Robert G. (BATTELLE (PACIFIC NW LAB)); Chenault, Jeffrey W. (BATTELLE (PACIFIC NW LAB)); Gano, Sue (BATTELLE (PACIFIC NW LAB))

2002-05-17T23:59:59.000Z

49

Thermal Conduction in Graphene and Graphene Multilayers  

E-Print Network (OSTI)

E. , and Ju, Y. S. , “ Heat conduction in novel electronicBalandin, A. A. , “Heat conduction in graphene: experimentalD. , “Simulation of heat conduction in suspended graphene

Ghosh, Suchismita

2009-01-01T23:59:59.000Z

50

Reduced Thermal Conductivity of Compacted Silicon Nanowires  

E-Print Network (OSTI)

Chen, “Coherent Phonon Heat Conduction in Superlattices,”1 Chapter 1: Heat Conduction in Nanostructured Materialsfindings. Chapter 1: Heat Conduction in Nanostructured

Yuen, Taylor S.

51

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

SciTech Connect

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

Stovall, Therese K [ORNL

2009-01-01T23:59:59.000Z

52

Thermal conductivity of $sup 238$PuO$sub 2$ powder, intermediates, and dense fuel forms  

SciTech Connect

The thermal conductivities of porous $sup 238$PuO$sub 2$ powder (calcined oxalate), milled powder, and high-density granules were calculated from direct measurements of steady-state temperature profiles resulting from self- heating. Thermal conductivities varied with density, temperature, and gas content of the pores. Errors caused by thermocouple heat conduction were less than 5 percent when the dimensions of the thermal conductivity cell and the thermocouple were properly selected. (auth)

Bickford, D.F.; Crain, B. Jr.

1975-10-01T23:59:59.000Z

53

Breaking the Thermal Conductivity Glass Limit  

Science Conference Proceedings (OSTI)

High Thermal Energy Storage Density LiNO3-KNO3-NaNO2-KNO2 Quaternary Molten Salt System for Parabolic Trough Concentrating Solar Power Generation.

54

THERMAL CONDUCTIVITY AND VISCOSITY OF GAS MIXTURES (thesis)  

SciTech Connect

Correlations based upon empirical modified equations derived from kinetic theory were developed for the thermal conductivity and viscosity of gas mixtures. The conductivity equation was compared to 226 binary mixture conductivities in temperatures from 0 to 774 deg C from the literature and this work. The average deviation is 2.1%. In correlating conductivity data of mixtures of polyatomic molecules, the energy transport is considered in two parts, i.e., one protion transferred by collision and the other by diffusion. The proposed viscosity equation reproduces 103 binary data points with an average deviation of 1.3%. These equations are more consistent with experiment than existing correlations in the literature. the relation of the conductivity or viscosity to composition and temperature are discussed in the light of the proposed equations. It has been demonstrated that, at a given composition, the ratio of the measured conductivity to that calculated on the molar average basis for mixtures of most simple molecules and the ratio of the measured viscosity to that calculated on the molar average basis for mixtures of most gases should be nearly constant over a temperature range of 200 to 300 deg C. The thermal conductivity of ten gases and selected binary and ternary mixtures of them were measured in a concentric silver cylinder cell in the temperature range of 100 to 540 deg C The gases are He, A, N/sub 2/, O/sub 2/, CO/sub 2/, CH/sub 4/, C/sub 2/ H/sub 4/, C/sub 3/H/sub 8/, methyl ether , and methyl formats. (auth)

Cheung, H.

1958-04-01T23:59:59.000Z

55

Effects of Composition and Granulometry on Thermal Conductivity of ...  

Science Conference Proceedings (OSTI)

It has been observed that thermal conductivity of cover material is strongly ... Experimental Investigation of Single Bubble Characteristics in a Cold Model of a ... Creep on Potroom Busbars and Electrical Insulation: Thermal-Electrical Aspects.

56

Thermal Conductivity Prediction of Nano Fluid Using ANN/GA  

Science Conference Proceedings (OSTI)

Abstract Scope, Thermal conductivities of nano fluid in a two-phase having different compositions of both base fluid as well as nano particles in a closed ...

57

Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance  

SciTech Connect

The thermal interface resistance at the macro scale is mainly described by the physical gap between two interfaces and constriction resistance due to this gap. The small gaps between the two material faces makes up the majority of thermal interface resistance at the macro scale. So, most of the studies have been focused on characterizing effect of surface geometry and material properties to thermal interface resistance. This resistance is more widely known as thermal contact resistance, represented with Rc. There are various models to predict thermal contact resistance at macro scale. These models predict thermal resistance Rc for given two materials by utilizing their bulk thermomechanical properties. Although, Rc represents thermal resistance accurately for macro size contacts between two metals, it is not suitable to describe interface resistance of particles in modern TIMs, aka particulate composites. The particles inside recently available TIMs are micron size and with effort to further increase surface area this particle size is approaching nano scale. At this small scale, Rc does not accurately predict thermal interface, as it is very difficult to characterize the surface topography. The thermal discontinuity at perfectly bonded interface of two dissimilar materials is termed as thermal boundary resistance (Rb) or Kapitza resistance. The macroscopic assumptions that thermal discontinuity only exists due to gaps and surface geometry leads to substantial error in determining interface thermal properties at micron and nano scale. The phenomenon of thermal boundary resistance is an inherent material property and arises due to fundamental mechanism of thermal transport. For metal-matrix particulate composites, Rb plays more important role than Rc. The free flowing nature of the polymer would eliminate most of the gaps between the two materials at their interface. This means almost all of the thermal resistance at particle/matrix interface would occur due to Rb. The current study presents experimental study of thermal boundary resistance for silica nano particles embedded inside epoxy resin. The bulk conductivity of the sample is measured and Rc is back calculated using Hasselman-Johnson s (H-J) equation. The numerical validation of the equation is also presented, including extrapolation study to predict effective conductivity of the nanocomposite TIM.

Kothari, Rushabh M [ORNL; Dinwiddie, Ralph Barton [ORNL; Wang, Hsin [ORNL

2013-01-01T23:59:59.000Z

58

COSMOLOGICAL MAGNETOHYDRODYNAMIC SIMULATIONS OF CLUSTER FORMATION WITH ANISOTROPIC THERMAL CONDUCTION  

SciTech Connect

The intracluster medium (ICM) has been suggested to be buoyantly unstable in the presence of magnetic field and anisotropic thermal conduction. We perform first cosmological simulations of galaxy cluster formation that simultaneously include magnetic fields, radiative cooling, and anisotropic thermal conduction. In isolated and idealized cluster models, the magnetothermal instability (MTI) tends to reorient the magnetic fields radially whenever the temperature gradient points in the direction opposite to gravitational acceleration. Using cosmological simulations of cluster formation we detect radial bias in the velocity and magnetic fields. Such radial bias is consistent with either the inhomogeneous radial gas flows due to substructures or residual MTI-driven field rearrangements that are expected even in the presence of turbulence. Although disentangling the two scenarios is challenging, we do not detect excess bias in the runs that include anisotropic thermal conduction. The anisotropy effect is potentially detectable via radio polarization measurements with LOFAR and the Square Kilometer Array and future X-ray spectroscopic studies with the International X-ray Observatory. We demonstrate that radiative cooling boosts the amplification of the magnetic field by about two orders of magnitude beyond what is expected in the non-radiative cases. This effect is caused by the compression of the gas and frozen-in magnetic field as it accumulates in the cluster center. At z = 0 the field is amplified by a factor of about 10{sup 6} compared to the uniform magnetic field that evolved due to the universal expansion alone. Interestingly, the runs that include both radiative cooling and thermal conduction exhibit stronger magnetic field amplification than purely radiative runs. In these cases, buoyant restoring forces depend on the temperature gradients rather than the steeper entropy gradients. Thus, the ICM is more easily mixed and the winding up of the frozen-in magnetic field is more efficient, resulting in stronger magnetic field amplification. We also demonstrate that thermal conduction partially reduces the gas accretion driven by overcooling despite the fact that the effective conductivity is suppressed below the Spitzer-Braginskii value.

Ruszkowski, M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Lee, D. [Department of Astronomy, ASC/Flash Center, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Brueggen, M. [School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen 05233 (Germany); Parrish, I. [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States); Oh, S. Peng, E-mail: mateuszr@umich.edu, E-mail: dongwook@flash.uchicago.edu, E-mail: m.brueggen@jacobs-university.de, E-mail: iparrish@astro.berkeley.edu, E-mail: peng@physics.ucsb.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

2011-10-20T23:59:59.000Z

59

Law for Thermal Conductivity of Crystalline Nanoporous Silicon Using Molecular Dynamic Simulations  

E-Print Network (OSTI)

G. A. , 2007. “Lattice thermal conductivity of nanoporousPore-size dependence of the thermal conductivity of porousand Chen, G. , 2004. “Thermal conductivity of nanoporous

Fang, Jin; Pilon, Laurent

2011-01-01T23:59:59.000Z

60

Thermal Conduction and Multiphase Gas in Cluster Cores  

E-Print Network (OSTI)

We examine the role of thermal conduction and magnetic fields in cores of galaxy clusters through global simulations of the intracluster medium (ICM). In particular, we study the influence of thermal conduction, both isotropic and anisotropic, on the condensation of multiphase gas in cluster cores. Previous hydrodynamic simulations have shown that cold gas condenses out of the hot ICM in thermal balance only when the ratio of the cooling time ($t_{\\rm cool}$) and the free-fall time ($t_{\\rm ff}$) is less than $\\approx 10$. Since thermal conduction is significant in the ICM and it suppresses local cooling at small scales, it is imperative to include thermal conduction in such studies. We find that anisotropic (along local magnetic field lines) thermal conduction does not influence the condensation criterion for a general magnetic geometry, even if thermal conductivity is large. However, with isotropic thermal conduction cold gas condenses only if conduction is suppressed (by a factor $\\lesssim 0.3$) with respe...

Wagh, Baban; McCourt, Michael

2013-01-01T23:59:59.000Z

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


61

Three Modes of Heat Transferâ??Thermal Conduction, Thermal Convection,  

Science Conference Proceedings (OSTI)

...).46, 44, 43, 42, 41, 40, 39, 38, 37, Ref 1In induction heating, all three modes of heat transferâ??conduction,

62

Measurement of Thermal Diffusity and Flow Resistance for TCAP Materials  

DOE Green Energy (OSTI)

SRS uses the Thermal Cycling Absorption Process (TCAP) to separate isotopes of hydrogen. The frequency of thermal cycles is a limit of the productivity of the process and that frequency is largely determined by the thermal diffusivity of the absorbent material. For a given tube diameter, a larger thermal diffusivity decreases the time required for each cycle. In 1998, the Engineering Development Laboratory measured thermal diffusivity and thermal conductivity for three TCAP materials in helium.

STEIMKE, JOHN

2004-11-11T23:59:59.000Z

63

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

DOE Patents (OSTI)

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

Poppendiek, Heinz F. (LaJolla, CA)

1982-01-01T23:59:59.000Z

64

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

SciTech Connect

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

Nguyen, Ba Nghiep; Henager, Charles H.

2013-04-20T23:59:59.000Z

65

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

66

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

67

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

68

Thermal Conductivity Database of Various Structural Carbon-Carbon  

Science Conference Proceedings (OSTI)

Advanced thermal protection materials envisioned for use on future hypersonic vehicles will likely be subjected to temperatures in excess of 1811 K (2800F) and, therefore, will require the rapid conduction of heat away from the stagnation regions of ...

Ohlhorst Craig W.; Vaughn Wallace L.; Ransone Philip O.; Tsou Hwa-Tsu

1997-11-01T23:59:59.000Z

69

Nanosecond time resolved thermal emission measurements during...  

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

Nanosecond time resolved thermal emission measurements during pulse excimer laser interaction with materials Title Nanosecond time resolved thermal emission measurements during...

70

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

SciTech Connect

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

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

2007-12-05T23:59:59.000Z

71

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

72

Thermal conductivity of dense quark matter and cooling of stars  

E-Print Network (OSTI)

The thermal conductivity of the color-flavor locked phase of dense quark matter is calculated. The dominant contribution to the conductivity comes from photons and Nambu-Goldstone bosons associated with breaking of baryon number which are trapped in the quark core. Because of their very large mean free path the conductivity is also very large. The cooling of the quark core arises mostly from the heat flux across the surface of direct contact with the nuclear matter. As the thermal conductivity of the neighboring layer is also high, the whole interior of the star should be nearly isothermal. Our results imply that the cooling time of compact stars with color-flavor locked quark cores is similar to that of ordinary neutron stars.

Igor A. Shovkovy; Paul J. Ellis

2002-04-11T23:59:59.000Z

73

Pretest Caluculations of Temperature Changes for Field Thermal Conductivity Tests  

Science Conference Proceedings (OSTI)

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

N.S. Brodsky

2002-07-17T23:59:59.000Z

74

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

SciTech Connect

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

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

2012-01-01T23:59:59.000Z

75

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

DOE Green Energy (OSTI)

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

Dinwiddie, R.B.; Beecher, S.C.; Porter, W.D. [Oak Ridge National Lab., TN (United States); Nagaraj, B.A. [General Electric Co., Cincinnati, OH (United States). Aircraft Engine Group

1996-05-01T23:59:59.000Z

76

Thermal Crosslinking of Organic Semiconducting Polythiophene Improves Transverse Hole Conductivity  

Science Conference Proceedings (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

77

Thermal conductivity of rocks associated with energy extraction from hot dry rock geothermal systems  

DOE Green Energy (OSTI)

Results of thermal conductivity measurements are given for 14 drill core rock samples taken from two exploratory HDR geothermal wellbores (maximum depth of 2929 m (9608 ft) drilled into Precambrian granitic rock in the Jemez Mountains of northern New Mexico. These samples have been petrographically characterized and in general represent fresh competent Precambrian material of deep origin. Thermal conductivities, modal analyses, and densities are given for all core samples studied under dry and water-saturated conditions. Additional measurements are reported for several sedimentary rocks encountered in the upper 760 m (2500 ft) of that same region. A cut-bar thermal conductivity comparator and a transient needle probe were used for the determinations with fused quartz and Pyroceram 9606 as the standards. The maximum temperature range of the measurements was from the ice point to 250/sup 0/C. The measurements on wet, water-saturated rock were limited to the temperature range below room temperature. Conductivity values of the dense core rock samples were generally within the range from 2 to 2.9 W/mK at 200/sup 0/C. Excellent agreement was achieved between these laboratory measurements of thermal conductivity and those obtained by in situ measurements used in the HDR wellbores. By using samples of sufficient thickness to provide a statistically representative heat flow path, no difference between conductivity values and their temperature coefficients for orthogonal directions (heat flow parallel or perpendicular to core axis) was observed. This isotropic behavior was even found for highly foliated gneissic specimens. Estimates of thermal conductivity based on a composite dispersion analysis utilizing pure minerallic phase conductivities and detailed modal analyses usually agreed to within 9 percent of the experimental values.

Sibbitt, W.L.; Dodson, J.G.; Tester, J.W.

1978-01-01T23:59:59.000Z

78

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

Open Energy Info (EERE)

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

79

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

80

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

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

Electrical conductivity and thermal dilepton rate from quenched lattice QCD  

E-Print Network (OSTI)

We report on a continuum extrapolation of the vector current correlation function for light valence quarks in the deconfined phase of quenched QCD. This is achieved by performing a systematic analysis of the influence of cut-off effects on light quark meson correlators at $T\\simeq 1.45 T_c$ using clover improved Wilson fermions. We discuss resulting constraints on the electrical conductivity and the thermal dilepton rate in a quark gluon plasma. In addition new results at 1.2 and 3.0 $T_c$ will be presented.

Olaf Kaczmarek; Anthony Francis

2011-09-19T23:59:59.000Z

82

Electrical conductivity and thermal dilepton rate from quenched lattice QCD  

E-Print Network (OSTI)

We report on a continuum extrapolation of the vector current correlation function for light valence quarks in the deconfined phase of quenched QCD. This is achieved by performing a systematic analysis of the influence of cut-off effects on light quark meson correlators at $T\\simeq 1.45 T_c$ using clover improved Wilson fermions. We discuss resulting constraints on the electrical conductivity and the thermal dilepton rate in a quark gluon plasma. In addition new results at 1.2 and 3.0 $T_c$ will be presented.

Kaczmarek, Olaf

2011-01-01T23:59:59.000Z

83

Role of Brownian Motion Hydrodynamics on Nanofluid Thermal Conductivity  

Science Conference Proceedings (OSTI)

We use a simple kinetic theory based analysis of heat flow in fluid suspensions of solid nanoparticles (nanofluids) to demonstrate that the hydrodynamics effects associated with Brownian motion have a minor effect on the thermal conductivity of the nanofluid. Our conjecture is supported by the results of molecular dynamics simulations of heat flow in a model nanofluid with well-dispersed particles. Our findings are consistent with the predictions of the effective medium theory as well as with recent experimental results on well dispersed metal nanoparticle suspensions.

W Evans, J Fish, P Keblinski

2005-11-14T23:59:59.000Z

84

Enhanced thermal conductivity of ethylene glycol with single-walled carbon nanotube inclusions  

E-Print Network (OSTI)

with the Hamilton-Crosser model, the Lu-Lin model, Nan`s effective medium theory and the Hashin-Strikman model to rest of the models. Networking of nanotubes to form a tri-dimensional structure was considered #12;models. Therefore, more studies need to be performed to measure the effective thermal conductivity

Maruyama, Shigeo

85

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

DOE Green Energy (OSTI)

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

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

1995-05-01T23:59:59.000Z

86

Light beam dynamics in materials with radially-inhomogeneous thermal conductivity  

E-Print Network (OSTI)

We study the properties of bright and vortex solitons in thermal media with nonuniform thermal conductivity and homogeneous refractive index, whereby the local modulation of the thermal conductivity strongly affects the entire refractive index distribution. While regions where the thermal conductivity is increased effectively expel light, self-trapping may occur in the regions with reduced thermal conductivity, even if such regions are located close to the material boundary. As a result, strongly asymmetric self-trapped beams may form inside a ring with reduced thermal conductivity and perform persistent rotary motion. Also, such rings are shown to support stable vortex solitons, which may feature strongly non-canonical shapes.

Kartashov, Yaroslav V; Torner, Lluis

2013-01-01T23:59:59.000Z

87

Infrared Thermography Measurements of Window Thermal Test Specimen...  

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

Infrared Thermography Measurements of Window Thermal Test Specimen: Surface Temperatures Title Infrared Thermography Measurements of Window Thermal Test Specimen: Surface...

88

Thermal interface conductance in Si/Ge superlattices by equilibrium molecular dynamics  

E-Print Network (OSTI)

We provide a derivation allowing the calculation of thermal conductance at interfaces by equilibrium molecular dynamics simulations and illustrate our approach by studying thermal conduction mechanisms in Si/Ge superlattices. ...

Esfarjani, Keivan

89

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

90

T I ENHANCING THERMAL CONDUCTIVITY OF FLUIDS WITH NANOPARTICLES*  

Office of Scientific and Technical Information (OSTI)

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

91

Role of thermal conduction in an advective accretion with bipolar outflows  

E-Print Network (OSTI)

Steady-state advective accretion flows in the presence of thermal conduction are studied. All three components of velocity in a spherical coordinates are considered and the flow displays both inflowing and outflowing regions according to our similarity solutions. Thermal conductivity provides latitudinal energy transport and so, the flow rotates more slowly and becomes hotter with increasing thermal conductivity coefficient. We also show that opening angle of the outflow region decreases as thermal conduction becomes stronger.

Khajenabi, Fazeleh

2013-01-01T23:59:59.000Z

92

Thermal Transport Measurement of Silicon-Germanium Nanowires  

E-Print Network (OSTI)

Thermal properties of one dimensional nanostructures are of interest for thermoelectric energy conversion. Thermoelectric efficiency is related to non dimensional thermoelectric figure of merit, ZT=S^2 o T/k, where S ,o , k and T are Seebeck coefficient, electrical conductivity, thermal conductivity and the absolute temperature respectively. These physical properties are interdependent. Therefore, making materials with high ZT is a very challenging task. However, nanoscale materials can overcome some of these limitations. When the size of nanomaterials is comparable to wavelength and mean free path of energy carriers, especially phonons, size effect contributes to the thermal conductivity reduction without bringing about major changes in the electrical conductivity and the Seebeck coefficient. Therefore, the figure of merit ZT can be manipulated. For example, the thermal conductivities of several silicon nanowires were more than two orders of magnitude lower than that of bulk silicon values due 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, 129nm and 177nm were measured using a batch fabricated micro device in a temperature range of 40K-450K. SiGe nanowires used in the experiment were synthesized via the Vapour-Liquid-Solid (VLS) growth method. The thermal conductivity data was compared with thermal conductivity of Si and Ge nanowires. The data was compared with SiGe alloy thin film, bulk SiGe, Si/SixGe1-x superlattice nanowire, Si/Si0.7Ge0.3 superlattice thin film and also with the thermal conductivity of Si0.5Ge0.5 calculated using the Einstein model. The thermal conductivities of these SiGe alloy nanowires observed in this work are ~20 times lower than Si nanowires, ~10 times lower than Ge nanowires, ~3-4 times lower than Si/SixGe1-x superlattice thin film, Si/SixGe1-x superlattice nanowire and about 3 time lower than bulk SiGe alloy. The low values of thermal conductivity are majorly due to the effect of alloy scattering, due to increased boundary scattering as a result of nanoscale diameters, and the interface diffuse scattering by core-shell effect. The influence of core-shell effect, alloy scattering and boundary scattering effect in reducing the thermal conductivity of these nanowires opens up opportunities for tuning thermoelectric properties which can pave way to thermoelectric materials with high figures of merit in the future.

Gwak, Yunki

2009-08-01T23:59:59.000Z

93

Thermal conductivity of silicic tuffs: predictive formalism and comparison with preliminary experimental results  

Science Conference Proceedings (OSTI)

Performance of both near- and far-field thermomechanical calculations to assess the feasibility of waste disposal in silicic tuffs requires a formalism for predicting thermal conductivity of a broad range of tuffs. This report summarizes the available thermal conductivity data for silicate phases that occur in tuffs and describes several grain-density and conductivity trends which may be expected to result from post-emplacement alteration. A bounding curve is drawn that predicts the minimum theoretical matrix (zero-porosity) conductivity for most tuffs as a function of grain density. Comparison of experimental results with this curve shows that experimental conductivities are consistently lower at any given grain density. Use of the lowered bounding curve and an effective gas conductivity of 0.12 W/m{sup 0}C allows conservative prediction of conductivity for a broad range of tuff types. For the samples measured here, use of the predictive curve allows estimation of conductivity to within 15% or better, with one exception. Application and possible improvement of the formalism are also discussed.

Lappin, A. R.

1980-07-01T23:59:59.000Z

94

Universal properties of thermal and electrical conductivity of gauge theory plasmas from holography  

E-Print Network (OSTI)

We show that for CFT's admitting gravity duals, thermal conductivity is fixed by central charges in a universal manner. We also discuss possible bound on thermal conductivity. Using this universality relation exhibited by thermal conductivity, we show how to express electrical conductivity in terms of thermodynamical quantities even in the presence of chemical potential i.e. electrical conductivity can be calculated without writing down perturbation equations and solving them even at nonvanishing chemical potential.

Jain, Sachin

2009-01-01T23:59:59.000Z

95

Effective Thermal Conductivity of High Temperature Insulations for Reusable Launch Vehicles  

E-Print Network (OSTI)

An experimental apparatus was designed to measure the effective thermal conductivity of various high temperature insulations subject to large temperature gradients representative of typical launch vehicle reentry aerodynamic heating conditions. The insulation sample cold side was maintained around room temperature, while the hot side was heated to temperatures as high as 1800°F. The environmental pressure was varied from 1 x 10 -4 to 760 torr. All the measurements were performed in a dry gaseous nitrogen environment. The effective thermal conductivity of the following insulation samples were measured: Saffilä at 1.5, 3, 6 lb/ft 3 , Q-Fiberä felt at 3, 6 lb/ft 3 , Cerachromeä at 6, 12 lb/ft 3 , and three multi-layer insulation configurations at 1.5 and 3 lb/ft 3 .. Introduction Metallic and refractory-composite thermal protection systems are being considered for a new generation of reusable launch vehicles (RLV). The main function of the thermal protection system (TPS) is to...

Kamran Daryabeigi

1999-01-01T23:59:59.000Z

96

Effective Thermal Conductivity of High Temperature Insulations for Reusable Launch Vehicles  

E-Print Network (OSTI)

An experimental apparatus was designed to measure the effective thermal conductivity of various high temperature insulations subject to large temperature gradients representative of typical launch vehicle reentry aerodynamic heating conditions. The insulation sample cold side was maintained around room temperature, while the hot side was heated to temperatures as high as 1800F. The environmental pressure was varied from 1 x 10 -4 to 760 torr. All the measurements were performed in a dry gaseous nitrogen environment. The effective thermal conductivity of the following insulation samples were measured: Saffil at 1.5, 3, 6 lb/ft 3 , Q-Fiber felt at 3, 6 lb/ft 3 , Cerachrome at 6, 12 lb/ft 3 , and three multi-layer insulation configurations at 1.5 and 3 lb/ft 3 .. Introduction Metallic and refractory-composite thermal protection systems are being considered for a new generation of reusable launch vehicles (RLV). The main function of the thermal protection system (TPS) is to mai...

Kamran Daryabeigi Langley

1999-01-01T23:59:59.000Z

97

Experimental Determination of the Effect of Reactor Radiation on the Thermal Conductivity of Uranium-Impregnated Graphite  

SciTech Connect

Experiments are described in which the change in thermal conductivity of U-impregnated graphite under neutron irradiation was measured. Thermal resistivities relative to the thermal resistivity of undamaged impregnated graphite are reorted as functions of exposure. From applications of the expermental results to the North American Aviation low-power research reactor the peak tem. of the core is determined for a given reactor power and time of operation.

Hetrick, D.L.; McCarty, W.K.; Steele, G.N.; Brown, M.S.; Clark, E.V.; Holmes, F.R.; Howard, D.F.; McElroy, W.N.; Shields, B.L.

1953-01-06T23:59:59.000Z

98

Thermal conductance and rectification of asymmetric tilt grain boundary in graphene  

E-Print Network (OSTI)

We have investigated the lattice thermal transport across the asymmetry tilt grain boundary between armchair and zigzag grains by using nonequilibrium molecular dynamics (NEMD). We have observed significant temperature drop and ultralow temperature-dependent thermal boundary resistance. Importantly, we find an unexpected thermal rectification phenomenon, i.e, the thermal conductivity and Kapitza conductance is asymmetric with respect to the thermal transport direction. And the effect of thermal rectification could be amplified by increasing the difference of temperature imposed on two sides. Our results propose a new promising kind of thermal rectifier and phonon diodes from polycrystalline graphene without delicate manupulation of the atomic structures.

Cao, Hai-Yuan; Gong, Xin-Gao

2011-01-01T23:59:59.000Z

99

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

SciTech Connect

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

100

High thermal conductivity connector having high electrical isolation  

DOE Patents (OSTI)

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

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

1995-01-01T23:59:59.000Z

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


101

Thermal conductivity from first-principles in bulk, disordered, and nanostructured materials  

E-Print Network (OSTI)

Thermal conductivity is an important transport property that plays a vital role in applications such as high efficiency thermoelectric devices as well as in thermal management of electronics. We present a first-principles ...

Garg, Jivtesh

2011-01-01T23:59:59.000Z

102

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

103

Measurements of the Electrical Conductivities of Air over Hot Water  

Science Conference Proceedings (OSTI)

Measurements of the conduction current between two electrodes in air over recently boiled water have been interpreted by Carlon as indicating that the humidified air became highly conductive and that large numbers of ions were produced in the air ...

C. B. Moore; B. Vonnegut

1988-03-01T23:59:59.000Z

104

Thermal conduction and particle transport in strong MHD turbulence, with application to galaxy-cluster plasmas  

E-Print Network (OSTI)

We investigate field-line separation in strong MHD turbulence analytically and with direct numerical simulations. We find that in the static-magnetic-field approximation the thermal conductivity in galaxy clusters is reduced by a factor of about 5-10 relative to the Spitzer thermal conductivity of a non-magnetized plasma. We also estimate how the thermal conductivity would be affected by efficient turbulent resistivity.

Benjamin D. G. Chandran; Jason L. Maron

2003-03-11T23:59:59.000Z

105

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

Open Energy Info (EERE)

Temperature, thermal-conductivity, and heat-flux data,Raft River area, Cassia County, Idaho (1974-1976) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report:...

106

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

E-Print Network (OSTI)

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

E. A. Ouellette; A. Harris

2010-08-04T23:59:59.000Z

107

A method for the thermal characterization, visualization, and integrity evaluation of conducting material samples or complex structures  

DOE Patents (OSTI)

This invention is useful in thermal imaging of conducting materials, and is particularly useful in measuring thermal conductivity and thermal boundary conditions in composite anisotropic materials, in materials of irregular shape, and in materials for high-temperature applications. It also has utility in visualizing the integrity of complex structures such as a machine, power plant, or chemical plant. The method is for modeling a conducting material sample or structure (system) as an electrical network of resistances, for measuring electric resistance between selected leads attached to the surface of the system, and, using basic circuit theory, for translating measured resistances into temperatures or indications of integrity in corresponding regions of the system. 10 figs.

Ortiz, M.G.

1991-12-31T23:59:59.000Z

108

Ground surface temperature reconstructions: Using in situ estimates for thermal conductivity acquired with a fiber-optic distributed thermal perturbation sensor  

Science Conference Proceedings (OSTI)

We have developed a borehole methodology to estimate formation thermal conductivity in situ with a spatial resolution of one meter. In parallel with a fiber-optic distributed temperature sensor (DTS), a resistance heater is deployed to create a controlled thermal perturbation. The transient thermal data is inverted to estimate the formation's thermal conductivity. We refer to this instrumentation as a Distributed Thermal Perturbation Sensor (DTPS), given the distributed nature of the DTS measurement technology. The DTPS was deployed in permafrost at the High Lake Project Site (67 degrees 22 minutes N, 110 degrees 50 minutes W), Nunavut, Canada. Based on DTPS data, a thermal conductivity profile was estimated along the length of a wellbore. Using the thermal conductivity profile, the baseline geothermal profile was then inverted to estimate a ground surface temperature history (GSTH) for the High Lake region. The GSTH exhibits a 100-year long warming trend, with a present-day ground surface temperature increase of 3.0 {+-} 0.8 C over the long-term average.

Freifeld, B.M.; Finsterle, S.; Onstott, T.C.; Toole, P.; Pratt, L.M.

2008-10-10T23:59:59.000Z

109

Determination of thermal parameters of one-dimensional nanostructures through a thermal transient method  

E-Print Network (OSTI)

of heat capacity and thermal conductivity measurements bythe heat pulse method for thermal transport measurements ofG. Speci?c heat and thermal conductivity measurements on

Arriagada, A.; Yu, E. T.; Bandaru, P. R.

2009-01-01T23:59:59.000Z

110

Estimating Salinity Variance Dissipation Rate from Conductivity Microstructure Measurements  

Science Conference Proceedings (OSTI)

At the smallest length scales, conductivity measurements include a contribution from salinity fluctuations in the inertial–convective and viscous–diffusive ranges of the turbulent scalar variance spectrum. Interpreting these measurements is ...

Jonathan D. Nash; James N. Moum

1999-02-01T23:59:59.000Z

111

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

Science Conference Proceedings (OSTI)

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

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

2009-07-15T23:59:59.000Z

112

Ion thermal conductivity for a pure tokamak plasma  

DOE Green Energy (OSTI)

The neoclassical and Pfirsch-Schlueter component of the ion heat conduction for a pure hydrogen Tokamak plasma are recalculated without assuming large aspect ratio and without neglecting energy scattering collisions. Using a model collision operator the conductivity is determined numerically for various collision frequencies and aspect ratios. An approximate algebraic expression is fitted to the results. Even for comparatively large aspect ratios(approx. 10) energy scattering increases the conductivity in the banana regime by about 50% and for small aspect ratios(approx. 3.3) the Pfirsch-Schlueter contribution causes a further increase of approximately 60%.

Bolton, C.; Ware, A.

1981-10-01T23:59:59.000Z

113

Thermal diffusivity and thermal conductivity of sintered UO2 and UO2-Gd2O3. Technical report  

SciTech Connect

The thermal diffusivity was measured using the laser flash method on sintered uranium dioxide (O/U=2.003, density=10.48X10 kg/m, from 300 to 2773 K), and urania and gadolinia mixed fuel (2,4 and 6 Wt% Gd2O3 content, from 600 to 1850 K). An equation was suggested for near-stoichiometric uranium dioxide over the temperature range 500-3100 K: K=(1-aP)(1/(A+BT)+DTxexp(-E/kT)x(1+H(E/kT+2)(sup 2))), where K in W/(m)(K), P is the fraction of porosity, a=2.74-5.8X10(sup 4-)T, A=3.68X10(sup 2-)(m)(K)/W, B=2.25X10(sup 4-)m/W, D=5.31X10(sup 3-)W/mXK2, H=0.264, E=1.15 ev, k is the Boltzmann constant. The thermal conductivity of UO2-Gd2O3 samples as a function of temperature and Gd2O3 content, X, could be expressed by phonon conduction; K=1/(A+BT) in the temperature range from 600 to 1700 K, where A=2.50 X+0.044(m)(K)/W.

Ying, S.; Ji, Z.

1988-01-01T23:59:59.000Z

114

Technical Project Plan for The Enhanced Thermal Conductivity of Oxide Fuels Through the Addition of High Thermal Conductivity Fibers and Microstructural Engineering  

SciTech Connect

The commercial nuclear power industry is investing heavily in advanced fuels that can produce higher power levels with a higher safety margin and be produced at low cost. Although chemically stable and inexpensive to manufacture, the in-core performance of UO{sub 2} fuel is limited by its low thermal conductivity. There will be enormous financial benefits to any utility that can exploit a new type of fuel that is chemically stable, has a high thermal conductivity, and is inexpensive to manufacture. At reactor operating temperatures, UO{sub 2} has a very low thermal conductivity (<5 W/m {center_dot}K), which decreases with temperature and fuel burnup. This low thermal conductivity limits the rate at which energy can be removed from the fuel, thus limiting the total integrated reactor power. If the fuel thermal conductivity could be increased, nuclear reactors would be able to operate at higher powers and larger safety margins thus decreasing the overall cost of electricity by increasing the power output from existing reactors and decreasing the number of new electrical generating plants needed to meet base load demand. The objective of the work defined herein is to produce an advanced nuclear fuel based on the current UO{sub 2} fuel with superior thermal conductivity and structural integrity that is suitable for current and future nuclear reactors, using the existing fuel fabrication infrastructure with minimal modifications. There are two separate components to the research: (1) Enhanced Thermal Conductivity (ETC) - adding high conductivity fibers to the UO{sub 2} prior to sintering, which act as conduits for moving the heat energy generated within the pellet to the outer surface, (2) Microstructural Engineering (ME) - adding second phase particulates to UO{sub 2} bodies to retard grain growth and to increase thermal conductivity, as well as improve fracture and creep resistance. Different groups will perform the laboratory work for each of these research components with some overlap in personnel. The overlapping areas primarily involve computer simulations and final testing of the fuel in a reactor. The estimated cost and duration of this project is $5,000,000 over three years.

Hollenbach, Daniel F [ORNL; Ott, Larry J [ORNL; Besmann, Theodore M [ORNL; Armstrong, Beth L [ORNL; Wereszczak, Andrew A [ORNL; Lin, Hua-Tay [ORNL; Ellis, Ronald James [ORNL; Becher, Paul F [ORNL; Jubin, Robert Thomas [ORNL; Voit, Stewart L [ORNL

2010-09-01T23:59:59.000Z

115

Ground surface temperature reconstructions: Using in situ estimates for thermal conductivity acquired with a fiber-optic distributed thermal perturbation sensor  

E-Print Network (OSTI)

with homogeneous thermal properties, to invert cooling data.thermal simulations of DTPS testing showing modeled coolingand cooling. The match between measured and modeled thermal

Freifeld, B.M.

2009-01-01T23:59:59.000Z

116

Composition-Dependent Thermal Conductivity of Several Binary ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Time-domain thermoreflectance (TDTR) measurements using a pump-and-probe femtosecond laser system are employed to rapidly evaluate ...

117

Investigation on the Thermal Conductivity of Resin Composite ...  

Science Conference Proceedings (OSTI)

A gas pycnometer was used for measuring volume. The specific heat of the ... Differential Characterization of Ikperejere Iron shale and Iron Sandstone Deposit.

118

Serpentine Thermal Coupling Between a Stream and a Conducting Body  

Science Conference Proceedings (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

119

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

SciTech Connect

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

120

Anomalously low thermal conductivity and thermoelectric properties of new cationic clathrates in the Sn-In-As-I system  

Science Conference Proceedings (OSTI)

Single-crystal samples of cationic clathrates in the Sn-In-As-I system with different indium contents have been synthesized. Their crystal structure has been analyzed and their thermoelectric properties have been measured. These compounds are found to be n-type semiconductors with high absolute values of the Seebeck coefficient (S = 400-600 {mu}V/K) and anomalously low thermal conductivity ({kappa} {materials. The reasons for the anomalously low thermal conductivity of these semiconductors are discussed and ways for optimizing their thermoelectric properties are shown.

Shevelkov, A. V.; Kelm, E. A.; Olenev, A. V. [Moscow State University, Faculty of Chemistry (Russian Federation); Kulbachinskii, V. A., E-mail: kulb@mig.phys.msu.ru; Kytin, V. G. [Moscow State University, Faculty of Physics (Russian Federation)

2011-11-15T23:59:59.000Z

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.


121

Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications  

DOE Green Energy (OSTI)

Preliminary studies were preformed to determine whether thermal conductivity of cementitious grouts used to backfill heat exchanger loops for geothermal heat pumps could be improved, thus improving efficiency. Grouts containing selected additives were compares with conventional bentonite and cement grouts. Significant enhancement of grout alumina grit, steel fibers, and silicon carbide increased the thermal conductivity when compared to unfilled, high solids bentonite grouts and conventional cement grouts. Furthermore, the developed grouts retained high thermal conductivity in the dry state, where as conventional bentonite and cement grouts tend to act as insulators if moisture is lost. The cementitious grouts studied can be mixed and placed using conventional grouting equipment.

Allan, M.L.

1996-06-01T23:59:59.000Z

122

Thermal desorption treatability test conducted with VAC*TRAX Unit  

SciTech Connect

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

1996-01-01T23:59:59.000Z

123

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

SciTech Connect

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

124

Measurements of prompt radiation induced conductivity of Kapton.  

SciTech Connect

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

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

2010-10-01T23:59:59.000Z

125

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

SciTech Connect

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

126

Cluster expansion and optimization of thermal conductivity in SiGe nanowires  

E-Print Network (OSTI)

We investigate the parametrization and optimization of thermal conductivity in silicon-germanium alloy nanowires by the cluster-expansion technique. Si1?xGex nanowires are of interest for thermoelectric applications and ...

Chan, Maria K.

127

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

128

Thermal Conduction in Aligned Carbon Nanotube–Polymer Nanocomposites with High Packing Density  

E-Print Network (OSTI)

Nanostructured composites containing aligned carbon nanotubes (CNTs) are very promising as interface materials for electronic systems and thermoelectric power generators. We report the first data for the thermal conductivity ...

Marconnet, Amy M.

129

The Effect of Soil Thermal Conductivity Parameterization on Surface Energy Fluxes and Temperatures  

Science Conference Proceedings (OSTI)

The sensitivity of sensible and latent heat fluxes and surface temperatures to the parameterization of the soil thermal conductivity is demonstrated using a soil vegetation atmosphere transfer scheme (SVATS) applied to intensive field campaigns (...

C. D. Peters-Lidard; E. Blackburn; X. Liang; E. F. Wood

1998-04-01T23:59:59.000Z

130

Anisotropic Thermal Conduction and the Cooling Flow Problem in Galaxy Clusters  

E-Print Network (OSTI)

We examine the long-standing cooling flow problem in galaxy clusters with 3D MHD simulations of isolated clusters including radiative cooling and anisotropic thermal conduction along magnetic field lines. The central regions of the intracluster medium (ICM) can have cooling timescales of ~200 Myr or shorter--in order to prevent a cooling catastrophe the ICM must be heated by some mechanism such as AGN feedback or thermal conduction from the thermal reservoir at large radii. The cores of galaxy clusters are linearly unstable to the heat-flux-driven buoyancy instability (HBI), which significantly changes the thermodynamics of the cluster core. The HBI is a convective, buoyancy-driven instability that rearranges the magnetic field to be preferentially perpendicular to the temperature gradient. For a wide range of parameters, our simulations demonstrate that in the presence of the HBI, the effective radial thermal conductivity is reduced to less than 10% of the full Spitzer conductivity. With this suppression of ...

Parrish, Ian J; Sharma, Prateek

2009-01-01T23:59:59.000Z

131

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

Science Conference Proceedings (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

132

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

133

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

134

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

Open Energy Info (EERE)

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

135

Thermal Conductivity of Wood-Derived Graphite and Copper-Graphite  

SciTech Connect

The thermal conductivity of wood-derived graphite and graphite/copper composites was studied both experimentally and using finite element analysis. The unique, naturally-derived, anisotropic porosity inherent to wood-derived carbon makes standard porosity-based approximations for thermal conductivity poor estimators. For this reason, a finite element technique which uses sample microstructure as model input was utilized to determine the conductivity of the carbon phase independent of porosity. Similar modeling techniques were also applied to carbon/copper composite microstructures and predicted conductivities were compared to those determined via experiment.

Johnson, M. T. [Northwestern University, Evanston; Childers, Amanda [Northwestern University, Evanston; Ramírez-Rico, J. [Universidad de Sevilla-CSIC, Spain; Wang, Hsin [ORNL; Faber, K. T. [Northwestern University, Evanston

2013-01-01T23:59:59.000Z

136

Influence of the temperature dependence of thermal parameters of heat conduction models on the reconstruction of thermal history of igneous-intrusion-bearing basins  

Science Conference Proceedings (OSTI)

Heat conduction models are important tools for reconstructing the thermal history of sedimentary basins affected by magmatic intrusions. Accurate thermal properties of the intrusion and its wall rocks are crucial for accurate predictions of thermal history. ... Keywords: Igneous intrusion, Peak temperature, Specific heat, Thermal conductivity, Vitrinite reflectance

Dayong Wang; Xiancai Lu; Yongchen Song; Rong Shao; Tian Qi

2010-10-01T23:59:59.000Z

137

ANISOTROPIC THERMAL CONDUCTION AND THE COOLING FLOW PROBLEM IN GALAXY CLUSTERS  

SciTech Connect

We examine the long-standing cooling flow problem in galaxy clusters with three-dimensional magnetohydrodynamics simulations of isolated clusters including radiative cooling and anisotropic thermal conduction along magnetic field lines. The central regions of the intracluster medium (ICM) can have cooling timescales of {approx}200 Myr or shorter-in order to prevent a cooling catastrophe the ICM must be heated by some mechanism such as active galactic nucleus feedback or thermal conduction from the thermal reservoir at large radii. The cores of galaxy clusters are linearly unstable to the heat-flux-driven buoyancy instability (HBI), which significantly changes the thermodynamics of the cluster core. The HBI is a convective, buoyancy-driven instability that rearranges the magnetic field to be preferentially perpendicular to the temperature gradient. For a wide range of parameters, our simulations demonstrate that in the presence of the HBI, the effective radial thermal conductivity is reduced to {approx}<10% of the full Spitzer conductivity. With this suppression of conductive heating, the cooling catastrophe occurs on a timescale comparable to the central cooling time of the cluster. Thermal conduction alone is thus unlikely to stabilize clusters with low central entropies and short central cooling timescales. High central entropy clusters have sufficiently long cooling times that conduction can help stave off the cooling catastrophe for cosmologically interesting timescales.

Parrish, Ian J.; Sharma, Prateek; Quataert, Eliot, E-mail: iparrish@astro.berkeley.ed [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States)

2009-09-20T23:59:59.000Z

138

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

139

Novel Charging Station and Computational Modeling for High Thermal Conductivity Heat Pipe Thermal Ground Planes.  

E-Print Network (OSTI)

??Thermal ground planes (TGPs) are planar, thin (thickness of 3 mm or less) heat pipes which use two-phase heat transfer. TGPs are innovative high-performance, integrated… (more)

Ababneh, Mohammed

2012-01-01T23:59:59.000Z

140

Regulation of thermal conductivity in hot galaxy clusters by MHD turbulence  

E-Print Network (OSTI)

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

Steven A. Balbus; Christopher S. Reynolds

2008-06-05T23:59:59.000Z

Note: This page contains sample records for the topic "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

Measurements of prompt radiation induced conductivity in Teflon (PTFE).  

SciTech Connect

We performed measurements of the prompt radiation induced conductivity (RIC) in thin samples of Teflon (PTFE) at the Little Mountain Medusa LINAC facility in Ogden, UT. Three mil (76.2 microns) samples were irradiated with a 0.5 %CE%BCs pulse of 20 MeV electrons, yielding dose rates of 1E9 to 1E11 rad/s. We applied variable potentials up to 2 kV across the samples and measured the prompt conduction current. Details of the experimental apparatus and analysis are reported in this report on prompt RIC in Teflon.

Hartman, E. Frederick; Zarick, Thomas Andrew; Sheridan, Timothy J.; Preston, E. [ITT Exelis Mission Systems, Colorado Springs, CO

2013-05-01T23:59:59.000Z

142

Universal properties of thermal and electrical conductivity of gauge theory plasmas from holography  

E-Print Network (OSTI)

We propose that for conformal field theories admitting gravity duals, the thermal conductivity is fixed by the central charges in a universal manner. Though we do not have a proof as yet, we have checked our proposal against several examples. This proposal, if correct, allows us to express electrical conductivity in terms of thermodynamical quantities even in the presence of chemical potential.

Sachin Jain

2009-12-14T23:59:59.000Z

143

Holographic electrical and thermal conductivity in strongly coupled gauge theory with multiple chemical potentials  

E-Print Network (OSTI)

We study transport coefficients of strongly coupled gauge theory in the presence of multiple chemical potential which are dual to rotating D3, M2 and M5 brane. Using the general form of the perturbation equations, we compute DC-electrical conductivity at finite temperature as well as at zero temperature. We also study thermal conductivity for the same class of black holes and show that thermal conductivity and viscosity obeys Wiedemann-Franz like law even in the presence of multiple chemical potential.

Sachin Jain

2009-12-11T23:59:59.000Z

144

Thermal conductivity of cementitious grouts for geothermal heat pumps. Progress report FY 1997  

DOE Green Energy (OSTI)

Grout is used to seal the annulus between the borehole and heat exchanger loops in vertical geothermal (ground coupled, ground source, GeoExchange) heat pump systems. The grout provides a heat transfer medium between the heat exchanger and surrounding formation, controls groundwater movement and prevents contamination of water supply. Enhanced heat pump coefficient of performance (COP) and reduced up-front loop installation costs can be achieved through optimization of the grout thermal conductivity. The objective of the work reported was to characterize thermal conductivity and other pertinent properties of conventional and filled cementitious grouts. Cost analysis and calculations of the reduction in heat exchanger length that could be achieved with such grouts were performed by the University of Alabama. Two strategies to enhance the thermal conductivity of cementitious grouts were used simultaneously. The first of these was to incorporate high thermal conductivity filler in the grout formulations. Based on previous tests (Allan and Kavanaugh, in preparation), silica sand was selected as a suitable filler. The second strategy was to reduce the water content of the grout mix. By lowering the water/cement ratio, the porosity of the hardened grout is decreased. This results in higher thermal conductivity. Lowering the water/cement ratio also improves such properties as permeability, strength, and durability. The addition of a liquid superplasticizer (high range water reducer) to the grout mixes enabled reduction of water/cement ratio while retaining pumpability. Superplasticizers are commonly used in the concrete and grouting industry to improve rheological properties.

Allan, M.L.

1997-11-01T23:59:59.000Z

145

SELF-SIMILAR STRUCTURE OF A HOT MAGNETIZED FLOW WITH THERMAL CONDUCTION  

Science Conference Proceedings (OSTI)

We have explored the structure of a hot magnetized accretion flow with thermal conduction. The importance of thermal conduction in hot accretion flows has been confirmed by observations of the hot gas surrounding Sgr A* and a few other nearby galactic nuclei. For a steady state structure of such accretion flows, a set of self-similar solutions is presented. In this paper, we have actually tried to re-check the solution presented by Abbassi et al. using a physical constraint. In this study, we find that Equation (29) places a new constraint that limits answers presented by Abbassi et al. In that paper, the parameter space, which is established in the new constraint, was plotted. However, the new requirement makes up only a small parameter space with physically acceptable solutions. And now in this paper, we have followed the idea with more effort and tried to find out how thermal conduction influences the structure of the disks in a physical parameter space. We have found that the existence of thermal conduction will lead to the reduction of accretion and radial and azimuthal velocities as well as the vertical thickness of the disk, which is slightly reduced. Moreover, the surface density of the disk will increase when thermal conduction becomes important in hot magnetized flow.

Ghasemnezhad, M.; Khajavi, M. [Department of Physics, School of Sciences, Ferdowsi University of Mashhad, Mashhad, 91775-1436 (Iran, Islamic Republic of); Abbassi, S., E-mail: abbassi@ipm.ir [School of Physics, Damghan University, P.O. Box 36715-364, Damghan (Iran, Islamic Republic of)

2012-05-01T23:59:59.000Z

146

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 heat pump is developed. The impact of soil thermal conductivity and pipe thermal conductivity on the soil temperature field around the buried pipe, and the thermal performance of the heat exchanger are simulated. The simulation results show that with the increase of soil thermal conductivity, heat transfer quantity obviously increases, and the temperature of soil around pipe decrease under winter conditions. The temperature field varies relatively faster with thermal conductivity in the site nearer to the buried pipe. With the increase of pipe thermal conductivity, heat transfer quantity and the mean temperature of the buried pipe's outside surface all increase.

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

2006-01-01T23:59:59.000Z

147

Low-Conductivity Thermal Barrier Coating for Gas Turbines: Material Testing Status  

Science Conference Proceedings (OSTI)

Advanced gas turbines rely on air-cooled components protected by ceramic thermal barrier coatings to survive increasingly high operating temperatures. A new generation of coatings offers lower thermal conductivity, potentially further reducing component heat loading, which can improve durability, lower life cycle cost, and enable longer range efficiency gains. Testing improved coatings is a necessary step towards field demonstration.BackgroundAs gas turbine ...

2012-12-31T23:59:59.000Z

148

Predicting Thermal Conductivity Evolution of Polycrystalline Materials Under Irradiation Using Multiscale Approach  

SciTech Connect

A multiscale methodology was developed to predict the evolution of thermal conductivity of polycrystalline fuel under irradiation. In the mesoscale level, phase field model was used to predict the evolution of gas bubble microstructure. Generation of gas atoms and vacancies were taken into consideration. In the macroscopic scale, a statistical continuum mechanics model was applied to predict the anisotropic thermal conductivity evolution during irradiation. Microstructure predicted by phase field model was fed into statistical continuum mechanics model to predict properties and behavior. Influence of irradiation intensity, exposition time and morphology were investigated. This approach provides a deep understanding on microstructure evolution and property prediction from a basic scientific viewpoint.

Li, Dongsheng; Li, Yulan; Hu, Shenyang Y.; Sun, Xin; Khaleel, Mohammad A.

2012-03-01T23:59:59.000Z

149

Phase-field modeling of temperature gradient driven pore migration coupling with thermal conduction  

SciTech Connect

Pore migration in a temperature gradient (Soret effect) is investigated by a phase-field model coupled with a heat transfer calculation. Pore migration is observed towards the high temperature domain with velocities that agree with analytical solution. Due to the low thermal conductivity of the pores, the temperature gradient across individual pores is increased, which in turn, accelerates the pore migration. In particular, for pores filled with xenon and helium, the pore velocities are increased by a factor of 2.2 and 2.1, respectively. A quantitative equation is then derived to predict the influence of the low thermal conductivity of pores.

Liangzhe Zhang; Michael R Tonks; Paul C Millett; Yongfeng Zhang; Karthikeyan Chockalingam; Bulent Biner

2012-04-01T23:59:59.000Z

150

temperature measurements conducted by the Gulf Coast Carbon Center  

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

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

151

012- Measurement of Thermal Conductivity of Basic Refractories ...  

Science Conference Proceedings (OSTI)

085- Highly Efficient Comprehensive Utilization of Kaolin Tailings from ... 086- Improvement in Gas Tightness of YSZ Coatings Produced by Atmospheric Plasma Spraying ... 145- The Synergy of XRD and XRF in a Shale and Slate Analysis.

152

Chandra constraints on the thermal conduction in the intracluster plasma of A2142  

E-Print Network (OSTI)

In this Letter, we use the recent Chandra observation of A2142 reported by Markevitch et al. to put constraints on thermal conduction in the intracluster plasma. We show that the observed sharp temperature gradient requires that classical conductivity has to be reduced at least by a factor of between 250 and 2500. The result provides a direct constraint on an important physical process relevant to the gas in the cores of clusters of galaxies.

S. Ettori; A. C. Fabian

2000-07-26T23:59:59.000Z

153

THE EFFECT OF ANISOTROPIC CONDUCTION ON THE THERMAL INSTABILITY IN THE INTERSTELLAR MEDIUM  

SciTech Connect

Thermal instability (TI) can strongly affect the structure and dynamics of the interstellar medium (ISM) in the Milky Way and other disk galaxies. Thermal conduction plays an important role in the TI by stabilizing small scales and limiting the size of the smallest condensates. In the magnetized ISM, however, heat is conducted anisotropically (primarily along magnetic field lines). We investigate the effects of anisotropic thermal conduction on the nonlinear regime of the TI by performing two-dimensional magnetohydrodynamic simulations. We present models with magnetic fields of different initial geometries and strengths, and compare them to hydrodynamic models with isotropic conduction. We find that anisotropic conduction does not significantly alter the overall density and temperature statistics in the saturated state of the TI. However, it can strongly affect the shapes and sizes of cold clouds formed by the TI. For example, for uniform initial fields long filaments of cold gas are produced that are reminiscent of some observed H I clouds. For initially tangled fields, such filaments are not produced. We also show that anisotropic conduction suppresses turbulence generated by evaporative flows from the surfaces of cold blobs, which may have implications for mechanisms for driving turbulence in the ISM.

Choi, Ena; Stone, James M. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2012-03-10T23:59:59.000Z

154

The Dynamics of Rayleigh-Taylor Stable and Unstable Contact Discontinuities with Anisotropic Thermal Conduction  

E-Print Network (OSTI)

We study the effects of anisotropic thermal conduction along magnetic field lines on an accelerated contact discontinuity in a weakly collisional plasma. We first perform a linear stability analysis similar to that used to derive the Rayleigh-Taylor instability (RTI) dispersion relation. We find that anisotropic conduction is only important for compressible modes, as incompressible modes are isothermal. Modes grow faster in the presence of anisotropic conduction, but growth rates do not change by more than a factor of order unity. We next run fully non-linear numerical simulations of a contact discontinuity with anisotropic conduction. The non-linear evolution can be thought of as a superposition of three physical effects: temperature diffusion due to vertical conduction, the RTI, and the heat flux driven buoyancy instability (HBI). In simulations with RTI-stable contact discontinuities, the temperature discontinuity spreads due to vertical heat conduction. This occurs even for initially horizontal magnetic f...

Lecoanet, Daniel; Quataert, Eliot

2012-01-01T23:59:59.000Z

155

Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition  

DOE Patents (OSTI)

The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

Carlsten, R.W.; Nissen, D.A.

1973-03-06T23:59:59.000Z

156

Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled carbon nanotube inclusions  

E-Print Network (OSTI)

the thermal conductivity at higher temperatures up to 6%. Computational modeling of SWCNTs in water using of water seeded with single-walled carbon nanotubes (SWCNT) synthesized using the alcohol catalytic this fluid for practical applications. We compare experimental results with existing analytical models

Maruyama, Shigeo

157

Thermal Inertia of Conductivity Cells: Observations with a Sea-Bird Cell  

Science Conference Proceedings (OSTI)

We have examined the magnitude and relaxation time of the thermal anomaly of the fluid flowing through the conductivity cell manufactured by Sea-Bird Electronics (SBE) that is induced by the heat stored in the wall of this cell using oceanic data ...

Rolf G. Lueck; James J. Picklo

1990-10-01T23:59:59.000Z

158

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

SciTech Connect

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

159

SIMULATIONS OF MAGNETOHYDRODYNAMICS INSTABILITIES IN INTRACLUSTER MEDIUM INCLUDING ANISOTROPIC THERMAL CONDUCTION  

SciTech Connect

We perform a suite of simulations of cooling cores in clusters of galaxies in order to investigate the effect of the recently discovered heat flux buoyancy instability (HBI) on the evolution of cores. Our models follow the three-dimensional magnetohydrodynamics of cooling cluster cores and capture the effects of anisotropic heat conduction along the lines of magnetic field, but do not account for the cosmological setting of clusters or the presence of active galactic nuclei (AGNs). Our model clusters can be divided into three groups according to their final thermodynamical state: catastrophically collapsing cores, isothermal cores, and an intermediate group whose final state is determined by the initial configuration of magnetic field. Modeled cores that are reminiscent of real cluster cores show evolution toward thermal collapse on a timescale which is prolonged by a factor of approx2-10 compared with the zero-conduction cases. The principal effect of the HBI is to re-orient field lines to be perpendicular to the temperature gradient. Once the field has been wrapped up onto spherical surfaces surrounding the core, the core is insulated from further conductive heating (with the effective thermal conduction suppressed to less than 10{sup -2} of the Spitzer value) and proceeds to collapse. We speculate that, in real clusters, the central AGN and possibly mergers play the role of 'stirrers', periodically disrupting the azimuthal field structure and allowing thermal conduction to sporadically heat the core.

Bogdanovic, Tamara; Reynolds, Christopher S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Balbus, Steven A. [Ecole Normale Superieure, Laboratoire de Radioastronomie, 24 rue Lhomond, 75231 Paris CEDEX 05 (France); Parrish, Ian J., E-mail: tamarab@astro.umd.ed, E-mail: chris@astro.umd.ed, E-mail: steven.balbus@lra.ens.f, E-mail: iparrish@astro.berkeley.ed [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States)

2009-10-10T23:59:59.000Z

160

Advancing Reactive Tracer Methods for Measuring Thermal Evolution...  

Open Energy Info (EERE)

History Facebook icon Twitter icon Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2- and Water-Based Geothermal Reservoirs Geothermal Lab Call Project...

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

Low Thermal Conductivity of RE4Si2O7N2 (RE=Y, Lu): A Systematic ...  

Science Conference Proceedings (OSTI)

The present work shows that identifying new low thermal conductivity ceramics can be realized by a combination approach of first-principles calculation and ...

162

Structure, thermal expansion and electrical conductivity of Nb-substituted LaCoO{sub 3}  

Science Conference Proceedings (OSTI)

The effect of Nb-substitution in LaCoO{sub 3} has been examined by evaluating the electrical conductivity, thermal expansion and crystal structure of the solid solutions LaCo{sub 1-x}Nb{sub x}O{sub 3} (x=0 to 1/3). It was demonstrated that Nb-substitution in LaCoO{sub 3} was mainly compensated by reduction of Co{sup 3+} to Co{sup 2+}, and that oxidation of Co{sup 2+} could destabilise the solid solution. The ambient crystal structure was shown to transform from rhombohedral R3{sup Macron }c perovskite (x=0) to orthorhombic Pbnm (x=0.15, 0.20) and finally to B-site ordered perovskite P2{sub 1}/n (x=0.25, 1/3) perovskite with increasing Nb-substitution. The thermal expansion of LaCo{sub 1-x}Nb{sub x}O{sub 3} was shown to be strongly depressed with increasing Nb-content, and significantly lower thermal expansion was observed for LaCo{sub 2/3}Nb{sub 1/3}O{sub 3} relative to LaCoO{sub 3}. The electrical conductivity was reduced with increasing Nb-content, and semi-conducting properties was demonstrated for LaCo{sub 1-x}Nb{sub x}O{sub 3} in contrast to the metallic behaviour of pure LaCoO{sub 3} at elevated temperature. The thermal expansion, electrical conductivity and the stability of the materials were discussed with emphasis on Co/Nb ordering, the oxidation state and spin transitions of Co. - Graphical abstract: Substitution of Nb in LaCoO{sub 3} increases the unit cell volume, reduces the symmetry of the unit cell and introduces cation ordering. The chemical substitution leads to suppression of the electronic conductivity and reduces the thermal expansion of the lattice. Highlights: Black-Right-Pointing-Pointer Cation ordering and crystal structure is reported for LaCo{sub x}Nb{sub 1-x}O{sub 3}. Black-Right-Pointing-Pointer Substitution of Nb in LaCoO{sub 3} is compensated by reduction of Co{sup 3+} to Co{sup 2+}. Black-Right-Pointing-Pointer Thermal expansion of LaCoO{sub 3} is reduced by Nb-substitution. Black-Right-Pointing-Pointer Electrical conductivity of LaCoO{sub 3} is reduced by Nb-substitution.

Oygarden, Vegar; Lein, Hilde L. [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Grande, Tor, E-mail: grande@ntnu.no [Department of Materials Science and Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

2012-08-15T23:59:59.000Z

163

Measurement of Thermal Dependencies of PBG Fiber Properties  

SciTech Connect

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

Laouar, Rachik

2011-07-06T23:59:59.000Z

164

Dissipative instability of MHD tangential discontinuity in magnetized plasmas with anisotropic viscosity and thermal conductivity.  

E-Print Network (OSTI)

The stability of the MHD tangential discontinuity is studied in compressible plasmas in the presence of anisotropic viscosity and thermal conductivity. The general dispersion equation is derived and solutions to this dispersion equation and stability criteria are obtained for the limiting cases of incompressible and cold plasmas. In these two limiting cases the effect of thermal conductivity vanishes and the solutions are only influenced by viscosity. The stability criteria for viscous plasmas are compared with those for ideal plasmas where stability is determined by the Kelvin-Helmholtz velocity VKH as a threshold for the difference in the equilibrium velocities. Viscosity turns out to have a destabilizing influence when the viscosity coefficient takes different values at the two sides of the discontinuity. Viscosity lowers the threshold velocity V c below the ideal KelvinHelmholtz velocity VKH , so that there is a range of velocities between V c and VKH where the overstability is of ...

Michael Ruderman; Erwin Verwichte; Robertus Erdelyi; Marcel Goossens; Elyiyy

1996-01-01T23:59:59.000Z

165

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

166

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

167

Thermal Characterization of Nanostructures and Advanced Engineered Materials  

E-Print Network (OSTI)

A. and McEuen, P. L. , “Thermal Transport Measurements ofTomanek, D. , “Unusually High Thermal Conductivity of Carbonand Lau, C. N. , “Superior thermal conductivity of single-

Goyal, Vivek Kumar

2011-01-01T23:59:59.000Z

168

Measurements of the Thermal Neutron Scattering Kernel  

E-Print Network (OSTI)

world's most powerful neutron source, the $1.4 billion Spallation Neutron Source At 1.4MW, SNS produces. SNS will feature 24 beamlines for physics, chemistry, biology, materials research. www.sns.gov #12 · Coproduction of epithermal, thermal and cold neutrons #12;SNS Instrument Beam Lines 1st experimentproposed 2nd

Danon, Yaron

169

Transient plane source measurements of the thermal ...  

Science Conference Proceedings (OSTI)

... conductivity of (2.1–2.2) W/(m K). While the HS bounds are fairly tight in Fig. ... Res 33:363–371 8. Xu Y, Chung DDL (2000) Effect of sand addition on ...

2007-11-14T23:59:59.000Z

170

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); Ivanov, Ilya N. (Knoxville, TN); Puretzky,; Alexander A. (Knoxville, TN)

2010-07-27T23:59:59.000Z

171

Microelectronic Thermal Anemometer for the Measurement of Surface Wind  

Science Conference Proceedings (OSTI)

The paper describes the development and first prototype results of a microelectronic thermal anemometer without moving parts, for the measurement of velocity and direction of surface wind. The central part of the instrument is an integrated-...

B. W. Van Oudheusden; J. H. Huijsing

1991-06-01T23:59:59.000Z

172

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

173

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 to 2 ?m. This was done by using a non-contact, non-invasive, in-situ Transient Thermo-Reflectance (TTR) laser based technique. The results demonstrated that the intrinsic thermal conductivity of a 40 nm PMMA film deposited on native oxide of silicon increases by a factor of three over bulk PMMA values, and a distinct increase in the thermal conductivity of PMMA film was observed in ultra-thin (sub 100 nm) films. This confirmed the importance of film thickness for the through-plane thermal conductivity value of PMMA film on native oxide of silicon.

Kim, Ick Chan

2007-05-01T23:59:59.000Z

174

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

Science Conference Proceedings (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

175

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

DOE Green Energy (OSTI)

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

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

2009-01-01T23:59:59.000Z

176

PROBLEM 13.94 KNOWN: Diameter, temperature and emissivity of boiler tube. Thermal conductivity and emissivity of  

E-Print Network (OSTI)

PROBLEM 13.94 KNOWN: Diameter, temperature and emissivity of boiler tube. Thermal conductivity of 0.5 mm), Td = 773 K nd the ash provides a significant resistance to heat transfer.a COMMENTS: Boiler

Rothstein, Jonathan

177

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

178

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

DOE Green Energy (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

179

Measurement and quantification of aggregate thermal coefficient of expansion  

E-Print Network (OSTI)

The coefficient of thermal expansion of concrete affects thermal related distresses in pavements. Factors affecting expansion of concrete and aggregates along with existing models are reviewed. A test method to measure the coefficient of thermal expansion of aggregates is proposed. Existing methods used to analyze oxide contents are evaluated. A relation between the oxide content of various elements in aggregates and the CTE of aggregate is presented. Results obtained from the proposed method are presented. A model is also presented for the CTE of concrete based on aggregate properties.

Chande, Gautam U

1997-01-01T23:59:59.000Z

180

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

E-Print Network (OSTI)

should be noted that the lattice thermal conductivity should88, 242107 ?2006? Cross-plane lattice and electronic thermalWe studied the cross-plane lattice and electronic thermal

2006-01-01T23:59:59.000Z

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


181

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

182

Method of making improved gas storage carbon with enhanced thermal conductivity  

SciTech Connect

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)

2002-01-01T23:59:59.000Z

183

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

DOE Patents (OSTI)

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

Ortiz, M.G.

1992-11-24T23:59:59.000Z

184

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 on the market. Three primary variables, including number of wire mesh layers, filler material, and temperature dependence were studied using an apparatus that was part of L.I.C.H.E.N (LabVIEW Integrated Conduction Heat Experiment Network), a setup whose basic components allow three vertically stacked samples to be thermally and mechanically controlled. Knowing the temperature profile in the upper and lower samples allows for determination of thermal conductivity of the middle material through the use of Fourier?s law. The numbers of layers investigated were two, four, six, and eight, with each separated by a metallic liner. The filler materials included air, s15, s35 and s60HS 3MTM hollow glass microspheres. The experiments were conducted at four temperatures of 300, 330, 366, and 400K with an interface pressure of 20 Psi. The experimental results indicated the ?number of layers? used was the primary factor in determining the effective thermal conductivity value. The addition of hollow glass microspheres as filler material resulted in statistically insignificant changes in effective thermal conductivity. Increasing the number of wire mesh layers resulted in a corresponding increase in effective thermal conductivity of the insulation. Changes in temperature had little to no effect on thermal conductivity. The effective thermal conductivity values for the proposed insulation structure ranged from 0.22 to 0.65 W/m-K, the lowest of which came from the two layer case having air as filler material. The uncertainties associated with the experimental results fell between 10 to 20 percent in all but a few cases. In the best performing cases, when compared with existing insulation technologies, thermal conductivity was approximately 3 to 10 times higher than these methods of insulation. Thus, the proposed insulation scheme with hollow glass-sphere filler material does not represent superior technology, and would be deemed uncompetitive with those readily available in the insulation market.

Mckenna, Sean

2008-12-01T23:59:59.000Z

185

Soil Thermal Properties Manual for Underground Power Transmission: Soil Thermal Property Measurements, Soil Thermal Stability, and the Use of Corrective Thermal Backfills  

Science Conference Proceedings (OSTI)

The thermal properties of soil used to bury underground transmission cables -- often only crudely estimated in the past -- can have a large impact on the capacity of a transmission system. This guide provides comprehensive information on soil thermal property measurement, surveying, interpretation, and improvement.

1997-12-02T23:59:59.000Z

186

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

SciTech Connect

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.

2013-01-01T23:59:59.000Z

187

Apparatus for Measurements of the Electrical Conductivity of Rainwater with High Resolution in Space and Time  

Science Conference Proceedings (OSTI)

Apparatus has been designed and constructed for real-time measurements of the electrical conductivity of rainwater. It utilizes a spinning disk that centrifuges and collects the rainwater failing on it A micro conductivity cell is employed, which ...

H. H. Jonsson; B. Vonnegut

1991-08-01T23:59:59.000Z

188

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

189

The Stability of Dilute Plasmas with Thermal and Composition Gradients. I. The Slow Conduction Limit: Overstable Gravity Modes  

E-Print Network (OSTI)

We analyze the stability of a dilute plasma with thermal and composition gradients in the limit where conduction is slow compared to the dynamical timescale. We find necessary and sufficient conditions for stability when the background magnetic field is either parallel or perpendicular to the thermal and composition gradients that are parallel to the gravitational field. We provide approximate solutions for all the relevant modes involved, which are driven by gravity, conduction, and diffusion. We discuss the astrophysical implications of our findings for a representative galaxy cluster where helium has sedimented.

Pessah, Martin E

2011-01-01T23:59:59.000Z

190

DIRECT MEASUREMENT OF HEAT FLUX FROM COOLING LAKE THERMAL IMAGERY  

SciTech Connect

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

191

Thermal conductivity depth-profile reconstruction of multilayered cylindrical solids using the thermal-wave Green function method  

Science Conference Proceedings (OSTI)

In this paper, a theoretical model for characterizing solid multi-layered cylindrical samples illuminated by a modulated uniform incident beam is developed by means of the Green function method. The specific Green function for the multi-layered cylindrical structure is derived and an analytical expression for the thermal-wave field in such a cylindrical sample is presented. The thermal-wave field of an inhomogeneous cylindrical sample irradiated with incident light of arbitrary angular and/or radial intensity distribution was obtained using this theoretical model. Furthermore, experimental validation is also presented in the form of experimental results with steel cylinders of various diameters.

Xie Guangxi [Key Lab of Modern Optical Technologies of Jiangsu Province, Institute of Modern Optical Technologies, Soochow University, Suzhou, Jiangsu, 215006 (China); Department of Physics, Jiangnan University, Wuxi, Jiangsu, 214122 (China); Zhang Jie; Liu Liwang; Wang Chinhua [Key Lab of Modern Optical Technologies of Jiangsu Province, Institute of Modern Optical Technologies, Soochow University, Suzhou, Jiangsu, 215006 (China); Mandelis, Andreas [Center for Advanced Diffusion-Wave Technologies (CADIFT), Department of Mechanical and Industrial Engineering, University of Toronto M5S 3G8, Ontario (Canada)

2011-06-01T23:59:59.000Z

192

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

Science Conference Proceedings (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

193

THERMAL PERFORMANCE MEASUREMENTS ON ULTIMATE HEAT SINKS - COOLING PONDS  

Office of Scientific and Technical Information (OSTI)

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

194

The Effect of Silicon on the Thermal Conductivity of Al-Si Alloys  

Science Conference Proceedings (OSTI)

In order to develop new die-cast aluminum alloys with adequate thermal ... Frequency Modulation Effect on the Solidification of Alloy 718 Fusion Zone.

195

Heat Conduction  

Science Conference Proceedings (OSTI)

Table 2   Differential equations for heat conduction in solids...conduction in solids General form with variable thermal properties General form with constant thermal properties General form, constant properties, without heat

196

Fabrication of nano-hole array patterns on transparent conducting oxide layer using thermally curable nanoimprint lithography  

Science Conference Proceedings (OSTI)

A two-dimensional, periodic array of nano-sized holes was fabricated in an indium tin oxide (ITO) layer, deposited onto a glass substrate with nanoimprint lithography. As a result of a thermally curing imprint process, hole array patterns with a diameter ... Keywords: Indium tin oxide (ITO), Nanoimprint lithography (NIL), Patterned transparent electrode, Photonic crystals, Transparent conducting oxide (TCO) layer

Kyeong-Jae Byeon; Seon-Yong Hwang; Heon Lee

2008-05-01T23:59:59.000Z

197

Apparatus and method for detecting and/or measuring flaws in conductive material  

Science Conference Proceedings (OSTI)

The present invention uses a magnet and sensor coil unilaterial and in relative motion to a conductive material, to measure perturbation or variation in the magnetic field in the presence of a flaw. A liftoff compensator measures a distance between the conductive material and the magnet.

Hockey, Ronald L. (Richland, WA); Riechers, Douglas M. (Richland, WA)

2000-01-01T23:59:59.000Z

198

IMPACT OF TEMPERATURE-DEPENDENT RESISTIVITY AND THERMAL CONDUCTION ON PLASMOID INSTABILITIES IN CURRENT SHEETS IN THE SOLAR CORONA  

SciTech Connect

In this paper, we investigate, by means of two-dimensional magnetohydrodynamic simulations, the impact of temperature-dependent resistivity and thermal conduction on the development of plasmoid instabilities in reconnecting current sheets in the solar corona. We find that the plasma temperature in the current-sheet region increases with time and it becomes greater than that in the inflow region. As secondary magnetic islands appear, the highest temperature is not always found at the reconnection X-points, but also inside the secondary islands. One of the effects of anisotropic thermal conduction is to decrease the temperature of the reconnecting X-points and transfer the heat into the O-points, the plasmoids, where it gets trapped. In the cases with temperature-dependent magnetic diffusivity, {eta} {approx} T {sup -3/2}, the decrease in plasma temperature at the X-points leads to (1) an increase in the magnetic diffusivity until the characteristic time for magnetic diffusion becomes comparable to that of thermal conduction, (2) an increase in the reconnection rate, and (3) more efficient conversion of magnetic energy into thermal energy and kinetic energy of bulk motions. These results provide further explanation of the rapid release of magnetic energy into heat and kinetic energy seen during flares and coronal mass ejections. In this work, we demonstrate that the consideration of anisotropic thermal conduction and Spitzer-type, temperature-dependent magnetic diffusivity, as in the real solar corona, are crucially important for explaining the occurrence of fast reconnection during solar eruptions.

Ni Lei; Roussev, Ilia I.; Lin Jun [Yunnan Astronomical Observatory, CAS, P.O. Box 110, Kunming 650011, Yunnan (China); Ziegler, Udo, E-mail: leini@ynao.ac.cn, E-mail: iroussev@ifa.hawaii.edu, E-mail: uziegler@aip.de [Leibniz-Institut fuer Astrophysik Potsdam, D-14482 Potsdam (Germany)

2012-10-10T23:59:59.000Z

199

Lattice Boltzmann modeling of the effective thermal conductivity for fibrous materials  

E-Print Network (OSTI)

J. , M. Wang, and Z. Li, A lattice Boltzmann algorithm forA novel thermal model for the lattice Boltzmann method inS. and Doolen G.D. , Lattice Boltzmann method for fluid

Wang, Moran; He, Jihuan; Yu, Jianyong; Pan, Ning

2007-01-01T23:59:59.000Z

200

EE5, Growth and Thermal Conductivity of Polycrystalline GaAs ...  

Science Conference Proceedings (OSTI)

A simple yet extensively used configuration for thermal management in high .... Microstructure and Properties of Colloidal ITO Films and Cold-Sputtered ITO Films .... Hybrid Inorganic-Organic Molecular Magnets on an Ultrathin Insulating Film.

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

Modeling Simulation Of Pyrolysis Of Biomass: Effect Of Thermal Conductivity, Reactor Temperature And Particle Size On Product Concentrations  

E-Print Network (OSTI)

The simultaneous chemical kinetics and heat transfer model is used to predict the effects of the most important physical and thermal properties (thermal conductivity, reactor temperature and particle size) of the feedstock on the convective-radiant pyrolysis of biomass fuels. The effects of these parameters have been analyzed for different geometries such as slab, cylinder and sphere. Finite difference method is employed for solving heat transfer model equation while Runge-Kutta 4 th order method is used for solving chemical kinetics model equations. Simulations are carried out for equivalent radius ranging from 0.0000125 m to 0.02 m, and temperature ranging from 303 K to 2100 K.

Chaurasia And Babu; A. S. Chaurasia; B. V. Babu

2003-01-01T23:59:59.000Z

202

Three-dimensional effect on the effective thermal conductivity of porous media  

E-Print Network (OSTI)

conductivity of multiphase random porous media. The energymorphology of multiphase random porous media. Wang’sfor multiphase conjugate heat transfer through a porous

Wang, Moran R Dr.; Wang, J K; Pan, N; Chen, S Y; He, J H

2007-01-01T23:59:59.000Z

203

Critical Evaluation of Current Skin Thermal Property Measurements  

E-Print Network (OSTI)

Burn treatment is an area of major importance in medicine, however, there is not currently an analytic method to determine the depth and magnitude of burns. Complications, such as a relative lack of knowledge of the specific thermal properties of skin and the relation between heat transfer and biological processes, have prevented a comprehensive model to explain the field of bioheat transfer. Research was conducted to estimate the relevant thermal and material properties in the field of bioheat transfer. Subsequently, an experiment was proposed, and a mathematical model was developed for the experiment, to allow for detection of burns through the use of heat transfer analysis. Burned skin and healthy skin differ in that there is no blood flow and thus no directionality to the heat transfer in burned skin. Thus, the experiment was designed to determine if there was a directionality was present in the heat transfer in the skin. Using the estimated skin properties, calculations were done to determine the viability of the proposed experiment. The experiment was refined to account for the findings and modified to more accurately detect burns in human skin. 1

Anand Mani

2013-01-01T23:59:59.000Z

204

Effects of Irradiation and Post-Irradiation Annealing on the Thermal Conductivity/ Diffusivity of Monolithic SIC and SIC/SIC Composites  

Science Conference Proceedings (OSTI)

Laser flash thermal diffusivity measurements were made on high-purity monolithic CVD-SiC (impurity concentration layup made by the isothermal chemical vapor infiltration process and with either a “thick” 1.0 µm or a “thin” 0.11 µm PyC fiber coating) before and after irradiation in the HFIR reactor (250 to 800°C, 4-8 dpa-SiC) and after post-irradiation annealing composite samples to 1200°C. Thermal conductivity in SiC is controlled by phonon transport. Point defects introduced into SiC during neutron irradiation are effective scattering centers for phonons, and as a consequence the thermal conductivity is sharply reduced. For irradiation temperatures below ~800°C, the accumulation of point defects (in SiC mostly single or small clusters of interstitials and isolated vacancies) saturates when the interstitial-vacancy recombination rate equals the defect production rate. For saturation conditions, the relative reduction in the SiC thermal conductivity decreases in a manner similar to its swelling reduction with increasing irradiation temperature. Examination of SiC swelling data at various irradiation temperatures and doses indicates that saturation occurs for ~2 dpa-SiC at 200°C and decreases continuously to ~0.4 dpa-SiC at 800°C. Based on a model that assumes a uniform distribution of the phonon scattering defects, the calculated defect concentration for unirradiated CVD-SiC was less than 1 appm, which is consistent with the manufacturer’s value of <5 wppm impurities. The defect concentrations estimated for the irradiated CVD-SiC samples decreased continuously from ~25,000 to 940 appm as the irradiation temperature increased from 252 to 800°C. The small intrinsic defect concentration in comparison to the rather large extrinsic irradiation-induced defect concentrations illustrates why CVD-SiC makes an ideal irradiation damage monitor.

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

2004-08-01T23:59:59.000Z

205

Mathematical model of a double-coil inductive transducer for measuring electrical conductivity  

Science Conference Proceedings (OSTI)

A technique for the contactless measurement of the electrical conductivity of conducting materials using a double-coil inductive transducer is presented. A mathematical model of the transducer has been created and it consists of two cylindrical coils and a tested sample in the form of a cylinder coaxial with the coils. A processing function of the transducer is defined as the ratio of voltages between terminals of the measurement coil with and without the test sample. This processing function depends on the conductivity of the test sample, the dimensions of the sample and of both coils of the transducer (the measurement coil and the excitation coil), and the frequency of the current supplied to the excitation coil. An analytical formula for the processing function is derived; analysis of graphs of this function in different formats enables us to evaluate the influence of all the essential parameters of the transducer. This is a necessary step for both transducer optimization and carrying out of the conductivity measurement of the investigated materials. In order to verify the theoretical predictions, experimental investigations have been performed using a computerized data acquisition system. First, an experimental validation of the obtained analytical formula has been completed using an aluminum sample of known conductivity. Then, the conductivity measurements of a sample made of brass have been carried out. The obtained experimental results confirm the high accuracy of the theoretical analysis.

Kusmierz, Jozef [Department of Electrical and Computer Engineering, Kielce University of Technology, Al. 1000-lecia P. P. 7, PL-25-314 Kielce (Poland)

2007-08-15T23:59:59.000Z

206

Thermal stability of proton conducting acid doped polybenzimidazole in simulated fuel cell environments  

Science Conference Proceedings (OSTI)

Recently, polybenzimidazole membrane doped with phosphoric acid (PBI) was found to have promising properties for use as a polymer electrolyte in a high temperature (ca. 150 to 200 C) proton exchange membrane direct methanol fuel cell. However, operation at 200 C in strongly reducing and oxidizing environments introduces concerns of the thermal stability of the polymer electrolyte. To simulate the conditions in a high temperature fuel cell, PBI samples were loaded with fuel cell grade platinum black, doped with ca. 480 mole percent phosphoric acid (i.e., 4.8 H{sub 3}PO{sub 4} molecules per PBI repeat unit) and heated under atmospheres of either nitrogen, 5% hydrogen, or air in a thermal gravimetric analyzer. The products of decomposition were taken directly into a mass spectrometer for identification. In all cases weight loss below 400 C was found to be due to loss of water. Judging from the results of these tests, the thermal stability of PBI is more than adequate for use as a polymer electrolyte in a high temperature fuel cell.

Samms, S.R.; Wasmus, S.; Savinell, R.F. [Case Western Reserve Univ., Cleveland, OH (United States)

1996-04-01T23:59:59.000Z

207

Thirty Stage Annular Centrifugal Contactor Thermal Profile Measurements  

Science Conference Proceedings (OSTI)

A thirty stage 5 cm annular centrifugal contactor cascade has been assembled and tested to obtain thermal profiles during both ambient and heated input conditions of operation. Thermocouples were installed on every stage as well as feed inputs and Real-time data was taken during experiments lasting from two to eight hours at total flow rates of 0.5 to 1.4 liters per minute. Ambient temperature profile results show that only a small amount of heat is generated by the mechanical energy of the contactors. Steady state temperature profiles mimic the ambient temperature of the lab but are higher toward the middle of the cascade. Heated inlet solutions gave temperature profiles with smaller temperature gradients, more driven by the temperature of the inlet solutions than ambient lab temperature. Temperature effects of solution mixing, even at rotor speeds of 4000 rpm, were not measurable.

David H. Meikrantz; Troy G. Garn; Jack D. Law

2010-02-01T23:59:59.000Z

208

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

SciTech Connect

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

209

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

E-Print Network (OSTI)

-liquid interfaces: Two approaches · Transient optical absorption of nanoparticles and nanotubes in liquid substrate. #12;Nanotubes in surfactant in water: Transient absorption · Optical absorption depends · Cooling rate (RC time constant) gives interface conductance G = 12 MW m-2 K-1G = 12 MW m K #12;Application

Braun, Paul

210

Effects of axial heat conduction and material properties on the performance characteristics of a thermal transient anemometer probe  

Science Conference Proceedings (OSTI)

This paper describes an investigation of the axial heat transfer within a thermal transient anemometer probe. A previous study, evaluated the performance characteristics of a thermal transient anemometer system. The study revealed discrepancies between a simplified theory and test results in the development of a universal calibration curve for probes of varying diameters. Although the cause of these discrepancies were left uncertain due to an inadequate theoretical model, the study suggested that axial conduction within the probe could account for the deviations. In this paper, computer simulations are used to further investigate axial heat conduction within the probes. The effect on calibration of axial variations of material properties along the probes is also discussed. Results from the computer simulation are used in lieu of the theoretical model used in the previous study to develop a satisfactory universal calibration curve. The computer simulations provide evidence that there is significant axial heat conduction within the probes, and that this was the cause of the discrepancies noted in the previous study.

Bailey, J.L.; Page, R.J. [Argonne National Lab., IL (United States); Acharya, M. [Illinois Inst. of Technology, Chicago, IL (United States). Fluid Dynamics Research Center

1995-07-01T23:59:59.000Z

211

Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis  

E-Print Network (OSTI)

Soil bulk density affects water storage, water and nutrient movement, and plant root activity in the soil profile. Its measurement is difficult in field conditions. Vibration-induced conductivity fluctuation was investigated to quantify soil bulk density with possible field applications in the future. The AC electrical conductivity of soil was measured using a pair of blade-like electrodes while exposing the soil to periodic vibration. The blades were positioned longitudinally and transversally to the direction of the induced vibration to enable the calculation of a normalized index. The normalized index was expected to provide data independent from the vibration strength and to reduce the effect of soil salinity and water content. The experiment was conducted on natural and salinized fine sand at two moisture conditions and four bulk densities. The blade-shaped electrodes improved electrode-soil contact compared to cylindrical electrodes, and thereby, reduced measurement noise. Simulations on a simplified re...

Kishne, Andrea Sz; Chang, Hung-Chih; Kish, Laszlo B

2007-01-01T23:59:59.000Z

212

A Method to Correct the Thermal Dome Effect of Pyranometers in Selected Historical Solar Irradiance Measurements  

Science Conference Proceedings (OSTI)

In using pyranometers to measure solar irradiance, it is important to know the magnitudes and the consequences of the thermal effect, which is introduced by the glass domes of the instruments. Historically, the thermal dome effect was not ...

Qiang Ji

2007-03-01T23:59:59.000Z

213

Spatial and temporal variations in streambed hydraulic conductivity quantified with time-series thermal methods  

E-Print Network (OSTI)

conductivity Streambed seepage Heat as a tracer Surface water­ground water interaction Pajaro River s u m m a r was 62 m3 s�1 , with most of the loss occurring along the lower part of the experimental reach. Point and with time, with greater seepage occurring along the lower part of the reach and during the summer and fall

Fisher, Andrew

214

Reactive and internal contributions to the thermal conductivity of local thermodynamic equilibrium nitrogen plasma: The effect of electronically excited states  

Science Conference Proceedings (OSTI)

Internal and reactive contributions to the thermal conductivity of a local thermodynamic equilibrium nitrogen plasma have been calculated using the Chapman-Enskog method. Low-lying (LL) electronically excited states (i.e., states with the same principal quantum number of the ground state) and high-lying (HL) ones (i.e., states with principal quantum number n> 2) have been considered. Several models have been developed, the most accurate being a model that treats the LL states as separate species while disregarding the presence of HL states, on account of their enormous transport cross sections.

Bruno, D.; Colonna, G.; Laricchiuta, A. [CNR IMIP Bari, Bari (Italy); Capitelli, M. [CNR IMIP Bari, Bari (Italy); Department of Chemistry, University of Bari, Bari, Italy and CNR IMIP Bari, Bari (Italy)

2012-12-15T23:59:59.000Z

215

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

E-Print Network (OSTI)

Ultra-deepwater reservoirs are important non-conventional reservoirs that hold the potential to produce billions of barrels of hydrocarbons but present major challenges. Hydraulic fracturing or frac-packing high permeability reservoirs is different from the conventional hydraulic fracturing technology used in low permeability formations. While the main purpose of the conventional technique is to create a long, highly conductive path, frac-packing on the other hand is used predominantly to get past near wellbore formation damage, control sand production and reduce near wellbore pressure drop. Ultra-deepwater reservoirs are usually high temperature and high pressure with high permeabilities. Frac-packing these types of wells requires short fractures packed with high proppant concentrations. Understanding the behavior of the fracture fluid and proppant is critical to pump such a job successfully and to ensure long term productivity from the fracture. A series of laboratory experiments have been conducted to research the different problems resulting from high temperature and pressure which negatively affect conductivity. Unlike conventional long-term conductivity measurements, we placed the proppant into the fracture and pumped fracture fluid through it and then measured conductivity by pumping oil to represent true reservoir conditions. Proppant performance and fracture fluids clean-up during production were examined. High strength proppant is ideal for deep fracture stimulations and in this study different proppant loadings at different stresses were tested to measure the impact of crushing and embedment on conductivity. The preliminary test results indicated that oil at reservoir conditions does improve clean-up of fracture fluid left back in the proppant pack. Increasing the proppant concentration in the fracture showed higher conductivity values even at high closure stress. The increase in effective closure stress with high temperature yielded significant loss in conductivity values as compared to those obtained from industry tests.

Fernandes, Preston X.

2009-08-01T23:59:59.000Z

216

Initial RF measurements of the CW normal-conducting RF injector  

Science Conference Proceedings (OSTI)

The LANL 2.5-cell, normal-conducting radio-frequency (NCRF) injector has been fabricated. We present initial results of low-power RF measurements (cavity Q, cavity field map, coupling beta, etc.) of the NCRF injector. The measured cavity Q and relative fields are found to be in good agreement with the design calculations and earlier measurements of Glidcop properties. However, the coupling beta of the ridge-loaded waveguides is found to be significantly higher than the design point. The impact of these low-power measurement results on the planned high-power RF and electron beam tests will be discussed.

Krawcyk, Frank L [Los Alamos National Laboratory; Moody, Nathan A [Los Alamos National Laboratory; Martinez, Felix A [Los Alamos National Laboratory; Nguyen, Dinh C [Los Alamos National Laboratory; Bolme, Gerald [Los Alamos National Laboratory; Young, Karen [Los Alamos National Laboratory; Toung, Lloyd [AES

2008-01-01T23:59:59.000Z

217

Thermal dilepton rate and electrical conductivity: An analysis of vector current correlation functions in quenched lattice QCD  

E-Print Network (OSTI)

We calculate the vector current correlation function for light valence quarks in the deconfined phase of QCD. The calculations have been performed in quenched lattice QCD at T=1.45 Tc for four values of the lattice cut-off on lattices up to size 128^3x48. This allows to perform a continuum extrapolation of the correlation function in the Euclidean time interval tau*T -in [0.2, 0.5], which extends to the largest temporal separations possible at finite temperature, to better than 1% accuracy. In this interval, at the value of the temperature investigated, we find that the vector correlation function never deviates from the free correlator for massless quarks by more than 9%. We also determine the first two non-vanishing thermal moments of the vector meson spectral function. The second thermal moment deviates by less than 7% from the free value. With these constraints, we then proceed to extract information on the spectral representation of the vector correlator and discuss resulting consequences for the electrical conductivity and the thermal dilepton rate in the plasma phase.

H. -T. Ding; A. Francis; O. Kaczmarek; F. Karsch; E. Laermann; W. Soeldner

2010-12-22T23:59:59.000Z

218

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

E-Print Network (OSTI)

A method has been developed for measuring heat losses from insulated systems in the field. While the measurements are not as precise as those made under laboratory conditions, they are more indicative of actual in service conditions. Extensive field tests have been carried out in petrochemical plants and power plants throughout the country. Some insulating materials have been found to lose up to 60% of their insulating value after a few years in service. Calcium silicate insulations were found to be the most durable.

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

1979-01-01T23:59:59.000Z

219

Development and application of diagnostic instrumentation for measurement of electron density and conductivity  

DOE Green Energy (OSTI)

The purpose of this contract was to assemble and demonstrate in the laboratory a Faraday rotation system for measurement of electron density and conductivity, with the intent to produce a system suitable for diagnostic support of the development of pulsed, space-based magnetohydrodynamic (MHD) power systems. Two system configurations were tested: (1) a rotating polarizer and (2) a beam splitting polarizer. Due to the short path length plasma produced in the laboratory flame, the long wavelength 496 {mu}m methyl fluoride laser line was used and only the more sensitive rotating polarizer configuration was used for the demonstration experiments. Electron number densities from 2 {times} 10{sup 19} to 9 {times} 10{sup 19} were measured with good agreement to statistical equilibrium (Saha) calculations using emission absorption-measured flame temperatures and neutral seed atom number seed atom nuclear densities. The electron collision frequencies were measured by transmission measurements. Combining these two measurements gave measured electron conductivities of between 4 and 12 mohs/m. These results compared reasonably well with those found with an electron collision frequency model combined with chemical equilibrium calculations and the emission absorption measurements. Ellipticity measurements of electron collision frequency were not possible due to the short path length of the laboratory plasma. 46 refs., 25 figs., 9 tabs.

Bauman, L.E.

1990-05-01T23:59:59.000Z

220

Effects of Vibrator Types and Their Placement on Bone?Conduction Threshold Measurements  

Science Conference Proceedings (OSTI)

Monaural bone?conduction threshold measurements in the quiet were obtained for 10 normally hearing young adults at both forehead and mastoid positions using two hearing?aid?type vibrators of different manufacture. Physical calibration data for the vibrators were obtained by other laboratories

Peter B. Weston; Roy W. Gengel; Ira J. Hirsh

1966-01-01T23:59:59.000Z

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


221

Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis  

E-Print Network (OSTI)

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

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

2007-05-03T23:59:59.000Z

222

Remote Sensing Measurements of Tropospheric Ozone by Ground-Based Thermal Emission Spectroscopy  

Science Conference Proceedings (OSTI)

Remote sensing measurements of the troposphere were obtained by a new technique in which spectra of the downward thermal radiation from tropospheric ozone were measured with a Fourier transform infrared spectrometer. The measurements were ...

W. F. J. Evans; E. Puckrin

1999-01-01T23:59:59.000Z

223

Developing Test Procedures for Measuring Stored Thermal Energy in Firefighter Protective Clothing.  

E-Print Network (OSTI)

??This research studied stored thermal energy in fire fighter's turnout systems. It developed a novel laboratory apparatus and test protocols for measuring the contribution of… (more)

Eni, Egbe Uchechi

2005-01-01T23:59:59.000Z

224

Measurement of thermal noise in multilayer coatings with optimized layer thickness  

Science Conference Proceedings (OSTI)

A standard quarter-wavelength multilayer optical coating will produce the highest reflectivity for a given number of coating layers, but in general it will not yield the lowest thermal noise for a prescribed reflectivity. Coatings with the layer thicknesses optimized to minimize thermal noise could be useful in future generation interferometric gravitational wave detectors where coating thermal noise is expected to limit the sensitivity of the instrument. We present the results of direct measurements of the thermal noise of a standard quarter-wavelength coating and a low noise optimized coating. The measurements indicate a reduction in thermal noise in line with modeling predictions.

Villar, Akira E.; Black, Eric D.; DeSalvo, Riccardo; Libbrecht, Kenneth G.; Michel, Christophe; Morgado, Nazario; Pinard, Laurent; Pinto, Innocenzo M.; Pierro, Vincenzo; Galdi, Vincenzo; Principe, Maria; Taurasi, Ilaria [LIGO Laboratory, California Institute of Technology, Mail Code 264-33, Pasadena, California 91125 (United States); Laboratoire des Materiaux Avances, Universite Claude Bernard Lyon 1, CNRS/IN2P3, Villeurbaune (France); Waves Group, University of Sannio at Benevento, Benevento, Italy, INFN and LSC (Italy)

2010-06-15T23:59:59.000Z

225

Standard Practice for Internal Temperature Measurements in Low-Conductivity Materials  

E-Print Network (OSTI)

1.1 This practice covers methods for instrumenting low-conductivity specimens for testing in an environment subject to rapid thermal changes such as produced by rocket motors, atmospheric re-entry, electric-arc plasma heaters, and so forth. Specifically, practices for bare-wire thermocouple instrumentation applicable to sheath-type thermocouples are discussed. 1.2 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

American Society for Testing and Materials. Philadelphia

2008-01-01T23:59:59.000Z

226

Photoacoustic infrared spectroscopy for conducting gas tracer tests and measuring water saturations in landfills  

Science Conference Proceedings (OSTI)

Highlights: Black-Right-Pointing-Pointer Photoacoustic infrared spectroscopy tested for measuring tracer gas in landfills. Black-Right-Pointing-Pointer Measurement errors for tracer gases were 1-3% in landfill gas. Black-Right-Pointing-Pointer Background signals from landfill gas result in elevated limits of detection. Black-Right-Pointing-Pointer Technique is much less expensive and easier to use than GC. - Abstract: Gas tracer tests can be used to determine gas flow patterns within landfills, quantify volatile contaminant residence time, and measure water within refuse. While gas chromatography (GC) has been traditionally used to analyze gas tracers in refuse, photoacoustic spectroscopy (PAS) might allow real-time measurements with reduced personnel costs and greater mobility and ease of use. Laboratory and field experiments were conducted to evaluate the efficacy of PAS for conducting gas tracer tests in landfills. Two tracer gases, difluoromethane (DFM) and sulfur hexafluoride (SF{sub 6}), were measured with a commercial PAS instrument. Relative measurement errors were invariant with tracer concentration but influenced by background gas: errors were 1-3% in landfill gas but 4-5% in air. Two partitioning gas tracer tests were conducted in an aerobic landfill, and limits of detection (LODs) were 3-4 times larger for DFM with PAS versus GC due to temporal changes in background signals. While higher LODs can be compensated by injecting larger tracer mass, changes in background signals increased the uncertainty in measured water saturations by up to 25% over comparable GC methods. PAS has distinct advantages over GC with respect to personnel costs and ease of use, although for field applications GC analyses of select samples are recommended to quantify instrument interferences.

Jung, Yoojin; Han, Byunghyun; Mostafid, M. Erfan; Chiu, Pei [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States); Yazdani, Ramin [Yolo County Planning and Public Works Department, Division of Integrated Waste Management, Yolo County, 44090 County Rd. 28H, Woodland, CA 95776 (United States); Imhoff, Paul T., E-mail: imhoff@udel.edu [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States)

2012-02-15T23:59:59.000Z

227

Interim procedure to measure the thermal performance of window systems  

SciTech Connect

The purpose of the report is to review the current sources of information on U-values and to describe the state of thermal test methods used for windows in order to provide the Bonneville Power Administration with some general guidelines in the application of thermal test data for use in the Model Conservation Standards (MCS) by the Northwest Power Planning Council. At present, considerable controversy exists in the window industry regarding the thermal testing of windows, therefore no consensus-based standards are available.

McCabe, M.E.; Goss, W.P.

1987-06-01T23:59:59.000Z

228

A high sensitivity ultralow temperature RF conductance and noise measurement setup  

SciTech Connect

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies.

Parmentier, F. D.; Mahe, A.; Denis, A.; Berroir, J.-M.; Glattli, D. C.; Placais, B.; Feve, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, CNRS UMR 8551, Universite P. et M. Curie, Universite D. Diderot 24, rue Lhomond, 75231 Paris Cedex 05 (France)

2011-01-15T23:59:59.000Z

229

Bond strength and stress measurements in thermal barrier coatings  

DOE Green Energy (OSTI)

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

Gell, M.; Jordan, E.

1995-12-31T23:59:59.000Z

230

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

Science Conference Proceedings (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

231

ESTIMATION OF IN-SITU THERMAL CONDUCTIVITIES FROM TEMPERATURE GRADIENT MEASUREMENTS  

E-Print Network (OSTI)

where: pc v • phonon heat capacity, c• phonon velocity,fluid density, the specific heat capacity of the fluid. Thean l8cm Values of heat capacities diameter casing for three

Hoang, V.T.

2010-01-01T23:59:59.000Z

232

Experimental Measurements of the Interface Thermal Conductance of a Lithium Metatitanate Pebble Bed  

Science Conference Proceedings (OSTI)

Tritium, Safety, and Environment / Eighteenth Topical Meeting on the Technology of Fusion Energy (Part 1)

A. Abou-Sena; A. Ying; M. Abdou

233

Thermal conductivity measurements of aerogel-impregnated shuttle tile at cryogenic temperatures  

Science Conference Proceedings (OSTI)

New materials are being designed to allow the implementation of innovative concepts in future space transportation vehicles. In present day spacecraft

B. P. M. Helvensteijn; J. R. Maddocks; L. J. Salerno; P. R. Roach; P. Kittel; S. M. White

2002-01-01T23:59:59.000Z

234

ESTIMATION OF IN-SITU THERMAL CONDUCTIVITIES FROM TEMPERATURE GRADIENT MEASUREMENTS  

E-Print Network (OSTI)

By analyzing the heat transfer process inside the tubing andnatural convection heat transfer process, three equationsis the dominant heat transfer process during shut-in, the

Hoang, V.T.

2010-01-01T23:59:59.000Z

235

ESTIMATION OF IN-SITU THERMAL CONDUCTIVITIES FROM TEMPERATURE GRADIENT MEASUREMENTS  

E-Print Network (OSTI)

in a Cir- culating Drilling Fluid," Journal of Petroleumtemperature after drilling, or injecting fluid. Bullard [14

Hoang, V.T.

2010-01-01T23:59:59.000Z

236

A17: Heat Capacity and Thermal Expansion Measurements of Solar ...  

Science Conference Proceedings (OSTI)

One of the main tasks for getting reliable cp and enthalpy data of solar salts is therefore to find the right measurement parameters and crucible material/salt ...

237

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

238

Estimation of Thermal Resistance from Room Temperature Electrical Resistance Measurements for Different LHC Beam Screen Support Systems  

E-Print Network (OSTI)

In this note the thermal resistance between the LHC beam screen and cold bore is estimated from room temperature electrical resistance measurements. The results indicate that the beam screen without supports should have a comparable, if not better, thermal performance than the one with the existing spring supports. This prediction from electrical resistance measurements is confirmed by recent preliminary thermal measurements.

Jenninger, B

1999-01-01T23:59:59.000Z

239

A field measurement system for the study of thermal comfort  

E-Print Network (OSTI)

metal screen. A platinum RTD measured air sors usedin theAir Temperature platinum RTD IVlEASURENIENT ACCURACY,Surface Temperature platinum RTD M: 06 m N/A N/A -+ 0 5°C

Benton, C.; Bauman, Fred; Fountain, M.

1990-01-01T23:59:59.000Z

240

The Braginskii model of the Rayleigh-Taylor instability. I. Effects of self-generated magnetic fields and thermal conduction in two dimensions  

E-Print Network (OSTI)

(abridged) There exists a substantial disagreement between computer simulation results and high-energy density laboratory experiments of the Rayleigh-Taylor instability Kuranz et al. (2010). We adopt the Braginskii formulation for transport in hot, dense plasma, implement and verify the additional physics modules, and conduct a computational study of a single-mode RTI in two dimensions with various combinations of the newly implemented modules. We find that magnetic fields reach levels on the order of 11 MG in the absence of thermal conduction. We observe denting of the RT spike tip and generation of additional higher order modes as a result of these fields. Contrary to interpretation presented in earlier work Nishiguchi (2002), the additional mode is not generated due to modified anisotropic heat transport effects but due to dynamical effect of self-generated magnetic fields. The main effects of thermal conduction are a reduction of the RT instability growth rate (by about 20% for conditions considered here)...

Modica, Frank; Zhiglo, Andrey

2013-01-01T23:59:59.000Z

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


241

Measure of Diffusion Model Error for Thermal Radiation Transport  

E-Print Network (OSTI)

The diffusion approximation to the equation of transfer (Boltzmann transport equation) is usually applied to media where scattering dominates the interactions. Diffusion approximation helps in significant savings in terms of code complexity and computational time. However, this approximation often has significant error. Error due to the inherent nature of a physics model is called model error. Information about the model error associated with the diffusion approximation is clearly desirable. An indirect measure of model error is a quantity that is related in some way to the error but not equal to the error. In general, indirect measures of error are expected to be less costly than direct measures. Perhaps the most well-known indirect measure of the diffusion model error is the variable-Eddington tensor. This tensor provides a great deal of information about the angular dependence of the angular intensity solution, but it is not always simple to interpret. We define a new indirect measure of the diffusion model error called the diffusion model error source (DME source). When this DME source is added to the diffusion equation, the transport solution for the angular-integrated intensity is obtained. In contrast to the variable-Eddington tensor, our DME source is a scalar that is conceptually easy to interpret. In addition to defining the DME source analytically, we show how to generate this source numerically relative to the Sn radiative transfer equations with linear-discontinuous spatial discretization. This numerical source is computationally tested and shown to reproduce the Sn solution for a number of problems. Our radiative transfer model solves a coupled, time dependent, multi-frequency, 1-D slab equation and material heat transfer equation. We then use diffusion approximation to solve the same problem. The difference due to this approximation can be modelled by a “diffusion source”. The diffusion source is defined as an amount of inhomogeneous source that, when added to a diffusion calculation, gives a solution for the angle-integrated intensity that is equal to the transport solution.

Kumar, Akansha

2013-05-01T23:59:59.000Z

242

Measurement of the Hydraulic Conductivity of Gravels Using a Laboratory Permeameter and Silty Sands Using Field Testing with Observation Wells.  

E-Print Network (OSTI)

??A new laboratory permeameter was developed for measuring the hydraulic conductivity of gravels ranging from 0.1 to 2 m/s. The release of pneumatic pressure applied… (more)

Judge, Aaron

2013-01-01T23:59:59.000Z

243

Report on Thermal Neutron Diffusion Length Measurement in Reactor Grade Graphite Using MCNP and COMSOL Multiphysics  

E-Print Network (OSTI)

Neutron diffusion length in reactor grade graphite is measured both experimentally and theoretically. The experimental work includes Monte Carlo (MC) coding using 'MCNP' and Finite Element Analysis (FEA) coding suing 'COMSOL Multiphysics' and Matlab. The MCNP code is adopted to simulate the thermal neutron diffusion length in a reactor moderator of 2m x 2m with slightly enriched uranium ($^{235}U$), accompanied with a model designed for thermal hydraulic analysis using point kinetic equations, based on partial and ordinary differential equation. The theoretical work includes numerical approximation methods including transcendental technique to illustrate the iteration process with the FEA method. Finally collision density of thermal neutron in graphite is measured, also specific heat relation dependability of collision density is also calculated theoretically, the thermal neutron diffusion length in graphite is evaluated at $50.85 \\pm 0.3cm$ using COMSOL Multiphysics and $50.95 \\pm 0.5cm$ using MCNP. Finally ...

Mirfayzi, S R

2013-01-01T23:59:59.000Z

244

Autonomous Measurements of Sea Surface Temperature Using In Situ Thermal Infrared Data  

Science Conference Proceedings (OSTI)

In situ and autonomous measurements of sea surface temperature (SST) have been performed with a thermal infrared radiometer mounted on a fixed oil rig. The accuracy limit was established at ±0.3 K for these SST measurements in order to meet the ...

Raquel Niclòs; Vicente Caselles; César Coll; Enric Valor; Eva Rubio

2004-04-01T23:59:59.000Z

245

MEASUREMENT OF THE HUMIDITY OF SOILS BY DIFFUSION OF A BEAM OF THERMAL NEUTRONS  

SciTech Connect

From earlier results on the measurement of soil humidity an apparatus was constructed and calibrated for the measurement of the humidity of soils by diffusion of a beam of thermal neutrons. The construction and calibration of this apparatus are described in detail. (J.S.R.)

Wack, B.

1962-02-01T23:59:59.000Z

246

Heat transfer simulation and thermal measurements of microfabricated x-ray transparent heater stages  

SciTech Connect

A microfabricated amorphous silicon nitride membrane-based nanocalorimeter is proposed to be suitable for an x-ray transparent sample platform with low power heating and built-in temperature sensing. In this work, thermal characterization in both air and vacuum are analyzed experimentally and via simulation. Infrared microscopy and thermoreflectance microscopy are used for thermal imaging of the sample area in air. While a reasonably large isothermal area is found on the sample area, the temperature homogeneity of the entire sample area is low, limiting use of the device as a heater stage in air or other gases. A simulation model that includes conduction, as well as radiation and convection heat loss, is presented with radiation and convection parameters determined experimentally. Simulated temperature distributions show that the homogeneity can be improved by using a thicker thermal conduction layer or reducing the pressure of the gas in the environment but neither are good solutions for the proposed use. A new simple design that has improved temperature homogeneity and a larger isothermal area while maintaining a thin thermal conduction layer is proposed and fabricated. This new design enables applications in transmission x-ray microscopes and spectroscopy setups at atmospheric pressure.

Baldasseroni, C. [Department of Materials Science and Engineering, University of California Berkeley, Berkeley, California 94720 (United States); Queen, D. R.; Cooke, David W.; Hellman, F. [Department of Physics, University of California Berkeley, Berkeley, California 94720 (United States); Maize, K.; Shakouri, A. [Department of Electrical Engineering, University of California Santa Cruz, Santa Cruz, California 95064 (United States)

2011-09-15T23:59:59.000Z

247

Thermal and Electrical Transport in Oxide Heterostructures  

E-Print Network (OSTI)

of thermal conductivity . . . . . . . . . . . . . . . .4.4 Thermal transport in2.3.2 Thermal transport . . . . . . . . . . . . . . . .

Ravichandran, Jayakanth

2011-01-01T23:59:59.000Z

248

Soil Thermal Resistivity and Thermal Stability Measuring Instrument: Volume 5: Abridged Manual for Use of the Statistical Weather Analysis Program  

Science Conference Proceedings (OSTI)

Numerous considerations influence the thermal design of an underground power cable, including the soil thermal resistivity, thermal diffusivity, and thermal stability. Each of these properties is a function of soil moisture which is, in turn, a function of past weather, soil composition, and biological burden. The Neher-McGrath formalism has been widely used for thermal cable design. However, this formalism assumes knowledge of soil thermal properties. For design purposes, these parameters should be trea...

1981-12-01T23:59:59.000Z

249

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 Conductivity of Snake River Plain Aquifer Sediments at the Idaho National Laboratory, Idaho By Kim S. Perkins saturated hydraulic conductivity of Snake River Plain aquifer sediments at the Idaho National Laboratory

250

An automated tool for three types of saturated hydraulic conductivity laboratory measurements  

SciTech Connect

Acquisition of porous medium hydraulic conductivity in the laboratory is usually time-consuming and costly because of the manual labor associated with the currently available techniques. Lately, there has been increased interest in automating hydraulic conductivity laboratory techniques to reduce analysis time and improve data consistency. A new apparatus is presented that is able to determine hydraulic conductivity values with the falling head, constant head, and constant flux methods in an automated fashion. In addition, the columns are designed forcing water to flow in a nominally one-dimensional manner throughout the porous medium. In this paper, hydraulic conductivity data for standard laboratory sands are presented and compared to results obtained using a standard Tempe cell configuration. Hydraulic conductivity values obtained with the new tool for the laboratory sands are consistent with literature data. For highly permeable sands, the newly obtained hydraulic conductivity values are considerable larger then values acquired using a Tempe cell configuration. The lower conductivity values for the Tempe Cell configuration are primarily the result of insufficient spreading of water in the inlet and outlet reservoirs.

Wietsma, Thomas W.; Oostrom, Martinus; Covert, Matthew A.; Queen, Theresa E.; Fayer, Michael J.

2009-03-01T23:59:59.000Z

251

Advancing Reactive Tracer Methods for Measuring Thermal Evolution in CO2-  

Open Energy Info (EERE)

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

252

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

253

Report on Thermal Neutron Diffusion Length Measurement in Reactor Grade Graphite Using MCNP and COMSOL Multiphysics  

E-Print Network (OSTI)

Neutron diffusion length in reactor grade graphite is measured both experimentally and theoretically. The experimental work includes Monte Carlo (MC) coding using 'MCNP' and Finite Element Analysis (FEA) coding suing 'COMSOL Multiphysics' and Matlab. The MCNP code is adopted to simulate the thermal neutron diffusion length in a reactor moderator of 2m x 2m with slightly enriched uranium ($^{235}U$), accompanied with a model designed for thermal hydraulic analysis using point kinetic equations, based on partial and ordinary differential equation. The theoretical work includes numerical approximation methods including transcendental technique to illustrate the iteration process with the FEA method. Finally collision density of thermal neutron in graphite is measured, also specific heat relation dependability of collision density is also calculated theoretically, the thermal neutron diffusion length in graphite is evaluated at $50.85 \\pm 0.3cm$ using COMSOL Multiphysics and $50.95 \\pm 0.5cm$ using MCNP. Finally the total neutron cross-section is derived using FEA in an inverse iteration form.

S. R. Mirfayzi

2013-01-08T23:59:59.000Z

254

Characterization of the Thermal Structure inside an Urban Canyon: Field Measurements and Validation of a Simple Model  

Science Conference Proceedings (OSTI)

The results of measurement campaigns are analyzed to investigate the thermal structure in an urban canyon and to validate a simplified model simulating the air and surface temperatures from surface energy budgets. Starting from measurements at ...

Lorenzo Giovannini; Dino Zardi; Massimiliano de Franceschi

2013-01-01T23:59:59.000Z

255

A High-Accuracy, Calibration-Free Technique for Measuring the Electrical Conductivity of Molten Oxides  

E-Print Network (OSTI)

reduction procedure is extraction of K from *In this analysis, the electrode is assumed to be equipotential assumption does not apply, the electrode must be modeled as a transmission line, and a_ much more complicated analysis must be employed to extract K from Z,,,,,,.[S1 The equivalent circuit for the measurement is shown

Sadoway, Donald Robert

256

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

SciTech Connect

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

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

1992-04-01T23:59:59.000Z

257

Hamilton-Jacobi and quantum theory formulations of thermal-wave propagation under the dual-phase lagging model of heat conduction  

SciTech Connect

Dual-phase lagging model is one of the most promising approaches to generalize the Fourier heat conduction equation, and it can be reduced in the appropriate limits to the hyperbolic Cattaneo-Vernotte and to the parabolic equations. In this paper it is shown that the Hamilton-Jacobi and quantum theory formulations that have been developed to study the thermal-wave propagation in the Fourier framework can be extended to include the more general approach based on dual-phase lagging. It is shown that the problem of solving the heat conduction equation can be treated as a thermal harmonic oscillator. In the classical approach a formulation in canonical variables is presented. This formalism is used to introduce a quantum mechanical approach from which the expectation values of observables such as the temperature and heat flux are obtained. These formalisms permit to use a methodology that could provide a deeper insight into the phenomena of heat transport at different time scales in media with inhomogeneous thermophysical properties.

Ordonez-Miranda, J.; Alvarado-Gil, J. J. [Department of Applied Physics, Cinvestav-Unidad Merida, Carretera Antigua a Progreso km. 6, A.P. Postal 73 'Cordemex', Merida, Yucatan 97310 (Mexico); Zambrano-Arjona, Miguel A. [Facultad de Ingenieria, Universidad Autonoma de Yucatan, A.P. 150 Cordemex, Merida, Yucatan 97310 (Mexico)

2010-02-15T23:59:59.000Z

258

Thermal Management of Solar Cells  

E-Print Network (OSTI)

phonon transmission and interface thermal conductance acrossF. Miao, et al. , "Superior Thermal Conductivity of Single-Advanced Materials for Thermal Management of Electronic

Saadah, Mohammed Ahmed

2013-01-01T23:59:59.000Z

259

Apparatus for characterizing conductivity of materials by measuring the effect of induced shielding currents therein  

DOE Patents (OSTI)

Apparatus and method for noncontact, radio-frequency shielding current characterization of materials is disclosed. Self- or mutual inductance changes in one or more inductive elements, respectively, occur when materials capable of supporting shielding currents are placed in proximity thereto, or undergo change in resistivity while in place. Such changes can be observed by incorporating the inductor(s) in a resonant circuit and determining the frequency of oscillation or by measuring the voltage induced on a coupled inductive element. The present invention is useful for determining the critical temperature and superconducting transition width for superconducting samples. 10 figures.

Doss, J.D.

1991-05-14T23:59:59.000Z

260

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

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

Heat transfer through porous multiphase systems measurement, modelling and applications in printing of coated papers.  

E-Print Network (OSTI)

??This work examines the thermal transfer through porous media by means of measurement of the effective thermal conductivity and modelling of the structural parameters. While… (more)

Gerstner, Philip

2010-01-01T23:59:59.000Z

262

Thermal performance of clean horizontal radiant barriers under winter conditions: Laboratory measurements and mathematical modeling  

Science Conference Proceedings (OSTI)

Several field experiments have been performed on attic radiant barriers under winter conditions; however, most of them have been confined to the fairly mild climates of Florida, Oklahoma, and Tennessee. Only one field experiment in a very cold climate (Canada) has been performed. In addition, no previous laboratory experiments under winter conditions have been performed on an attic both with and without a radiant barrier. This paper presents the results of laboratory measurements of the thermal performance of clean horizontal radiant barriers in a simulated residential attic module under nighttime or low solar gain daytime winter conditions. Comparing tests under the same conditions with and without a radiant barrier shows that the addition of a clean horizontal radiant barrier to insulation at the R-22 to R-25 level decreases the ceiling heat flow by 6 to 8%. The experimental results were found to be in very good agreement with predictions made with a mathematical model for the thermal performance of attics.

Wilkes, K.E.; Childs, P.W.

1992-01-01T23:59:59.000Z

263

Thermal performance of clean horizontal radiant barriers under winter conditions: Laboratory measurements and mathematical modeling  

Science Conference Proceedings (OSTI)

Several field experiments have been performed on attic radiant barriers under winter conditions; however, most of them have been confined to the fairly mild climates of Florida, Oklahoma, and Tennessee. Only one field experiment in a very cold climate (Canada) has been performed. In addition, no previous laboratory experiments under winter conditions have been performed on an attic both with and without a radiant barrier. This paper presents the results of laboratory measurements of the thermal performance of clean horizontal radiant barriers in a simulated residential attic module under nighttime or low solar gain daytime winter conditions. Comparing tests under the same conditions with and without a radiant barrier shows that the addition of a clean horizontal radiant barrier to insulation at the R-22 to R-25 level decreases the ceiling heat flow by 6 to 8%. The experimental results were found to be in very good agreement with predictions made with a mathematical model for the thermal performance of attics.

Wilkes, K.E.; Childs, P.W.

1992-08-01T23:59:59.000Z

264

Thermal neutron capture cross section of gadolinium by pile-oscillation measurements in MINERVE  

SciTech Connect

Natural gadolinium is used as a burnable poison in most LWR to account for the excess of reactivity of fresh fuels. For an accurate prediction of the cycle length, its nuclear data and especially its neutron capture cross section needs to be known with a high precision. Recent microscopic measurements at Rensselaer Polytechnic Inst. (RPI) suggest a 11% smaller value for the thermal capture cross section of {sup 157}Gd, compared with most of evaluated nuclear data libraries. To solve this inconsistency, we have analyzed several pile-oscillation experiments, performed in the MINERVE reactor. They consist in the measurement of the reactivity variation involved by the introduction in the reactor of small-samples, containing different mass amounts of natural gadolinium. The analysis of these experiments is done through the exact perturbation theory, using the PIMS calculation tool, in order to link the reactivity effect to the thermal capture cross section. The measurement of reactivity effects is used to deduce the 2200 m.s-1 capture cross section of {sup nat}Gd which is (49360 {+-} 790) b. This result is in good agreement with the JEFF3.1.1 value (48630 b), within 1.6% uncertainty at 1{sigma}, but is strongly inconsistent with the microscopic measurements at RPI which give (44200 {+-} 500) b. (authors)

Leconte, P.; Di-Salvo, J.; Antony, M.; Pepino, A. [CEA, DEN, DER, Cadarache, F-13108 Saint-Paul-Lez-Durance (France); Hentati, A. [International School in Nuclear Engineering, Cadarache, F-13108 Saint-Paul-Lez-Durance (France)

2012-07-01T23:59:59.000Z

265

A Theory for the Retrievals of Virtual Temperature from Remote Measurements of Horizontal Winds and Thermal Radiation  

Science Conference Proceedings (OSTI)

This paper develops a theory for the estimation of virtual temperature from remote measurements of (i) emitted thermal radiation by microwave and infrared radiometers and (ii) horizontal winds by Doppler radars (or lidars). The problem of ...

Tzvi Gal-Chen

1988-06-01T23:59:59.000Z

266

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

SciTech Connect

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

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

1983-02-01T23:59:59.000Z

267

A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction  

SciTech Connect

We describe the design, construction, calibration, and two different applications of a miniature capacitance dilatometer. The device is suitable for thermal expansion and magnetostriction measurements from 300 K down to about 25 mK, with a resolution of 0.02 A at low temperatures. The main body of the dilatometer is fabricated from a single block of a Be-Cu alloy by electrical discharge milling. This creates an extremely compact high-resolution measuring cell. We have successfully tested and operated dilatometers of this new type with the commonly used physical property measurement system by quantum design, as well as with several other cryogenic refrigeration systems down to 25 mK and in magnetic fields up to 20 T. Here, the capacitance is measured with a commercially available capacitance bridge. Using a piezoelectric rotator from Attocube Systems, the cell can be rotated at T= 25 mK inside of an inner vacuum chamber of 40 mm diameter. The miniaturized design for the one-axis rotation setup allows a rotation of 360 Degree-Sign .

Kuechler, R.; Bauer, T.; Brando, M.; Steglich, F. [Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden (Germany)

2012-09-15T23:59:59.000Z

268

A steady-state Bi-substrate technique for measurement of the thermal conductivity of ceramic coatings  

E-Print Network (OSTI)

of heat injection and removal, the heater power and cooling water flow rate are fixed and the system,11]. This paper presents an analysis of the method and a brief study of the issues affecting accuracy are generated by heating the lower substrate with an electric resistance heater, while heat is continuously

Cambridge, University of

269

Measurement of density, temperature, and electrical conductivity of a shock-compressed nonideal nitrogen plasma in the megabar pressure range  

Science Conference Proceedings (OSTI)

Kinematic and thermodynamic parameters of shock-compressed liquid nitrogen are measured behind the front of a plane shock wave using plane wave and hemispherical shock wave generators. In these experiments, high values of compression parameters (shock-compressed hydrogen density {approx} 3.25 g/cm{sup 3} and temperature T{approx} 56000 K at a pressure of P {approx} 265 GPa) are attained. The density, pressure, temperature, and electrical conductivity of the nonideal plasma of shock-compressed liquid nitrogen are measured. A nearly isochoric behavior of the nitrogen shock adiabat is observed in the pressure range P = 100-300 GPa. The thermodynamics of shock-compressed nitrogen is an alyzed using the model of the equation of state in the quasi-chemical representation (SAHA code) as well as the semiempirical wide-range equation of state developed at the Institute of Experimental Physics. Experimental results are interpreted on the basis of calculations as the fixation of the boundary of transition of shock-compressed nitrogen from the polymer phase to the state of a strongly nonideal plasma at P {approx} 100 GPa, {approx} 3.4 g/cm{sup 3}.

Mochalov, M. A.; Zhernokletov, M. V.; Il'kaev, R. I.; Mikhailov, A. L. [Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation); Fortov, V. E. [Russian Academy of Sciences (IVTAN), Joint Institute for High Temperatures (Russian Federation); Gryaznov, V. K. [Russian Academy of Sciences, Chernogolovka, Institute of Problems of Chemical Physics (Russian Federation); Iosilevskiy, I. L., E-mail: ilios@orc.r [Russian Academy of Sciences (IVTAN), Joint Institute for High Temperatures (Russian Federation); Mezhevov, A. B.; Kovalev, A. E.; Kirshanov, S. I.; Grigor'eva, Yu. A.; Novikov, M. G.; Shuikin, A. N. [Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)

2010-01-15T23:59:59.000Z

270

High-resolution thermal expansion measurements under helium-gas pressure  

Science Conference Proceedings (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

271

Thermal Transport in Graphene Multilayers and Nanoribbons  

E-Print Network (OSTI)

1 CHAPTER 2 Thermal transport atvalues of graphene’s thermal conductivity and different1 Thermal conductivity : metals and non - metallic

Subrina, Samia

2011-01-01T23:59:59.000Z

272

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

Science Conference Proceedings (OSTI)

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

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

2005-01-01T23:59:59.000Z

273

An apparatus for simultaneous measurement of electrical conductivity and thermopower of thin films in the temperature range of 300-750 K  

SciTech Connect

An automated apparatus capable of measuring the electrical conductivity and thermopower of thin films over a temperature range of 300-750 K is reported. A standard dc resistance measurement in van der Pauw geometry was used to evaluate the electrical conductivity, and the thermopower was measured using the differential method. The design of the instrument, the methods used for calibration, and the measurement procedure are described in detail. Given the lack of a standard National Institute of Standards and Technology (Gaithersburg, Md.) sample for high temperature thermopower calibration, the disclosed calibration procedure shall be useful for calibration of new instruments.

Ravichandran, J. [Applied Science and Technology Graduate Group, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kardel, J. T.; Scullin, M. L. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Bahk, J.-H.; Bowers, J. E. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Heijmerikx, H. [Department of Physics, University of California, Berkeley, California 94720 (United States); Majumdar, A. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)

2011-01-15T23:59:59.000Z

274

Induced-polarization measurements at Roosevelt Hot Springs Thermal area, Utah  

DOE Green Energy (OSTI)

An induced polarization survey was conducted at Roosevelt Hot Springs, using the dipole-dipole array. The survey consisted of two profile lines, one across the southern end of the system (2200N) and another across the northern portion (5950N). A total of 15 line-km of profiles was run, with 100 m and 300 m dipoles out to n spacings of 4 to 6. Apparent resistivity amplitude and phase data were gathered with a phase-sensitive receiver at frequencies between 32 Hz and 1/256 Hz. The data are presented in the form of apparent resistivity of phase pseudosections. Induced polarization effects in geothermal environments can result from clays and pyrite which are associated with hydrothermal alteration. Laboratory measurements on altered material show some induced polarization effects at frequencies below 1 Hz which are thought to be due to pyrite. A higher frequency polarization (> 1 Hz) is attributed to the effects of clays. The primary purpose of this survey was to investigate the feasibility of mapping clay alteration zones, and separating them from other conductive features, by making use of their polarization characteristics. The field data show some small, low frequency phase anomalies which may be the result of pyrite deposition. The higher frequencies show considerable phase effects, which can be the result of clays, but the effects of electromagnetic coupling have not, as yet, been assessed.

Chu, J.J.; Sill, W.R.; Ward, S.H.

1979-06-01T23:59:59.000Z

275

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

DOE Green Energy (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

276

Ground truth measurements plan for the Multispectral Thermal Imager (MTI) satellite  

SciTech Connect

Sandia National Laboratories (SNL), Los Alamos National Laboratory (LANL), and the Savannah River Technology Center (SRTC) have developed a diverse group of algorithms for processing and analyzing the data that will be collected by the Multispectral Thermal Imager (MTI) after launch late in 1999. Each of these algorithms must be verified by comparison to independent surface and atmospheric measurements. SRTC has selected 13 sites in the continental U.S. for ground truth data collections. These sites include a high altitude cold water target (Crater Lake), cooling lakes and towers in the warm, humid southeastern US, Department of Energy (DOE) climate research sites, the NASA Stennis satellite Validation and Verification (V and V) target array, waste sites at the Savannah River Site, mining sites in the Four Corners area and dry lake beds in the southwestern US. SRTC has established mutually beneficial relationships with the organizations that manage these sites to make use of their operating and research data and to install additional instrumentation needed for MTI algorithm V and V.

Garrett, A.J.

2000-01-03T23:59:59.000Z

277

Shocked H2O ice: Thermal emission measurements and the criteria for phase changes during impact events  

E-Print Network (OSTI)

Shocked H2O ice: Thermal emission measurements and the criteria for phase changes during impact/s will initiate phase changes on icy surfaces. Thus, shock-induced melting and vaporization of ice is a widespread from shocked H2O ice and derive peak and post-shock temperatures. Under shock pressures between 8

Stewart, Sarah T.

278

STEP—A Temperature Profiler for Measuring the Oceanic Thermal Boundary Layer at the Ocean–Air Interface  

Science Conference Proceedings (OSTI)

A fast measuring system has been designed and built to determine the oceanic thermal microstructure at the ocean–air interface. The system consists of a profiler sonde, which amends through the uppermost few meters of the ocean with a time of ...

Theodor C. Mammen; Nikolaus von Bosse

1990-04-01T23:59:59.000Z

279

Measurement of single and double glazing thermal performance under realistic conditions using the mobile window thermal test (MoWiTT) facility  

SciTech Connect

The thermal performance of single glazing, clear double glazing, and double glazing with a low-emissivity coating was measured in both south-facing and north-facing orientations under realistic field conditions using the new MoWiTT field test facility. The time-dependent net heat flow through each fenestration was found to be consistent with the predictions of the standard simplified heat transfer model, provided that an angle-dependent shading coefficient is used and diffuse solar gain is included in the calculation. Summer-condition average U-values were derived for each glazing type and were found to agree with the expected values for both types of double glazing. The measured U-value for single glazing was lower than predicted.

Klems, J.; Keller, H.

1986-11-01T23:59:59.000Z

280

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)

The objective of this research was to determine the effect of thermal cycling combined with mechanical loading on the development of microcracks in M40J/PMR-II- 50, the second generation aerospace application material. The objective was pursued by finding the critical controlling parameters for microcrack formation from mechanical stress-thermal cycling test. Three different in-plane strains (0%, 0.175~0.350%, and 0.325~0.650%) were applied to the composites by clamping composite specimens (M40J/PMR-II-50, [0,90]s, a unitape cross-ply) on the radial sides of half cylinders having two different radii (78.74mm and 37.96mm). Three different thermal loading experiments, 1) 23oC to �196oC to 250oC, 2) 23oC to 250oC, and 3) 23oC to -196oC, were 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-thermal cycling experiment was simplified to obtain main and interaction factors by applying 2k factorial design from the various factors affecting microcrack density of M40J/PMR-II-50. Observations indicate that the higher temperature portion of the cycle under load causes fiber/matrix interface failure. Subsequent exposure to higher stresses in the cryogenic temperature region results in composite matrix microcracking due to the additional stresses associated with the fiber-matrix thermal expansion mismatch.

Ju, Jaehyung

2005-08-01T23:59:59.000Z

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

Estimating Liquid Fluxes in Thermally Perturbed Fractured Rock Using Measured Temperature Profiles  

E-Print Network (OSTI)

requires the heat-transfer processes to be approximatelyindicates that the heat-transfer processes along thethe conductive heat-transfer processes below the heater are

Birkholzer, Jens T.

2005-01-01T23:59:59.000Z

282

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

DOE Green Energy (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

283

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

284

Modified Fowler-Milne method for the spectroscopic determination of thermal plasma temperature without the measurement of continuum radiation  

Science Conference Proceedings (OSTI)

A technique based on the Fowler-Milne method for the spectroscopic determination of thermal plasma temperatures without measuring continuum radiation is presented. This technique avoids the influence of continuum radiation with the combined line and continuum emission coefficients to derive the plasma temperatures. The amount of continuum emission coefficient is estimated by using an expression related to the Biberman factors. Parameters that affect the accuracy of the proposed technique and errors in the measured plasma temperatures are analyzed. It is shown that, by using the Ar I 696.5 nm line with a bandwidth of 3.27 nm without taking into account the continuum radiation, the plasma temperature measured will be lower on the order of up to 1000-3000 K for temperatures from 20 000 to 24 000 K. The theoretically predicted temperature errors are in good agreement with the experimental results, indicating that the proposed technique is reliable for plasma temperature measurement.

Ma Shuiliang [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China); Plasma Research Laboratory, Australian National University, Canberra ACT 0200 (Australia); Gao Hongming; Wu Lin [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China)

2011-01-15T23:59:59.000Z

285

Measurement of the Equivalent Thermal Resistance of Rooftop Lawns in a Hot-Climate Wind Tunnel  

E-Print Network (OSTI)

In a very hot summer equivalent to a Guangzhou summer, the reduction of heat coming into rooms is very important with respect to thermal comfort and energy efficiency. The objective of this study is to investigate the evaporation cooling effect on a rooftop lawn. A hot-climate wind tunnel experiment was carried out in order to obtain and analyze the heat and moisture transport in the rooftop lawn. Furthermore, a calculation with the energy conservation equation was carried out using the results of the hot-climate wind tunnel experiment. The calculated equivalent thermal resistance and synthesis exterior surface heat transfer coefficient were in fairly good agreement with that in the design standard for energy efficiency of residential buildings in the hot summer and warm winter zone, while the average velocity in hot-climate wind tunnel equals the summer average outdoor velocity in Guangzhou.

Meng, Q.; Zhang, Y.; Zhang, L.

2006-01-01T23:59:59.000Z

286

Thermal Transport in Graphene Multilayers and Nanoribbons  

E-Print Network (OSTI)

80 CHAPTER 5 Heat Conduction in Few Layerto Fourier's Law of heat conduction, thermal conductivity isnext experiments on heat conduction in graphene structures

Subrina, Samia

2011-01-01T23:59:59.000Z

287

Fuzzy Categorization of Weather Conditions for Thermal Mapping  

Science Conference Proceedings (OSTI)

Thermal mapping is a technique that uses a vehicle-mounted infrared radiometer to measure the variation of road surface temperature (RST). Conventionally, the technique is conducted under three qualitatively categorized weather conditions: ...

J. Shao

2000-10-01T23:59:59.000Z

288

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

289

Considerations and measurements of latent-heat-storage salts for secondary thermal battery applications  

Science Conference Proceedings (OSTI)

Given its potential benefits, the practicality of using a latent heat-storage material as the basis for a passive thermal management system is being assessed by Chloride Silent Power Ltd. (CSPL) with technical assistance from Beta Power, Inc. and Sandia National Laboratories (SNL). Based on the experience gained in large-scale solar energy storage programs, fused salts were selected as the primary candidates for the heat-storage material. The initial phase of this assessment was directed to an EV battery being designed at CSPL for the ETX-II program. Specific tasks included the identification and characterization of potential fused salts, a determination of placement options for the salts within the battery, and an assessment of the ultimate benefit to the battery system. The results obtained to date for each of these tasks are presented in this paper.

Koenig, A.A.; Braithwaite, J.W.; Armijo, J.R.

1988-05-16T23:59:59.000Z

290

Uncertainty analysis routine for the Ocean Thermal Energy Conversion (OTEC) biofouling measurement device and data reduction procedure. [HTCOEF code  

DOE Green Energy (OSTI)

Biofouling and corrosion of heat exchanger surfaces in Ocean Thermal Energy Conversion (OTEC) systems may be controlling factors in the potential success of the OTEC concept. Very little is known about the nature and behavior of marine fouling films at sites potentially suitable for OTEC power plants. To facilitate the acquisition of needed data, a biofouling measurement device developed by Professor J. G. Fetkovich and his associates at Carnegie-Mellon University (CMU) has been mass produced for use by several organizations in experiments at a variety of ocean sites. The CMU device is designed to detect small changes in thermal resistance associated with the formation of marine microfouling films. An account of the work performed at the Pacific Northwest Laboratory (PNL) to develop a computerized uncertainty analysis for estimating experimental uncertainties of results obtained with the CMU biofouling measurement device and data reduction scheme is presented. The analysis program was written as a subroutine to the CMU data reduction code and provides an alternative to the CMU procedure for estimating experimental errors. The PNL code was used to analyze sample data sets taken at Keahole Point, Hawaii; St. Croix, the Virgin Islands; and at a site in the Gulf of Mexico. The uncertainties of the experimental results were found to vary considerably with the conditions under which the data were taken. For example, uncertainties of fouling factors (where fouling factor is defined as the thermal resistance of the biofouling layer) estimated from data taken on a submerged buoy at Keahole Point, Hawaii were found to be consistently within 0.00006 hr-ft/sup 2/-/sup 0/F/Btu, while corresponding values for data taken on a tugboat in the Gulf of Mexico ranged up to 0.0010 hr-ft/sup 2/-/sup 0/F/Btu. Reasons for these differences are discussed.

Bird, S.P.

1978-03-01T23:59:59.000Z

291

Solar and Thermal Radiation Errors on Upper-Air Radiosonde Temperature Measurements  

Science Conference Proceedings (OSTI)

Atmospheric temperature and humidity profiles are important for weather prediction, but climate change has increased the interest in upper-air observations asking for very high-quality reference measurements. This paper discusses an experimental ...

R. Philipona; A. Kräuchi; G. Romanens; G. Levrat; P. Ruppert; E. Brocard; P. Jeannet; D. Ruffieux; B. Calpini

2013-10-01T23:59:59.000Z

292

Solar and Thermal Radiation Errors on Upper-Air Radiosonde Temperature Measurements  

Science Conference Proceedings (OSTI)

Atmospheric temperature and humidity profiles are important for weather prediction, but climate change has increased the interest in upper-air observations asking for very high quality reference measurements. Here we show an experimental approach ...

R. Philipona; A. Kräuchi; G. Romanens; G. Levrat; P. Ruppert; E. Brocard; P. Jeannet; D. Ruffieux; B. Calpini

293

Characterization of Thermal Effects in Pyranometers: A Data Correction Algorithm for Improved Measurement of Surface Insolation  

Science Conference Proceedings (OSTI)

Pyranometers are reliable, economical radiometers commonly used to measure solar irradiances at the surface in a long-term, monitoring mode. This paper presents a discussion of the response of these instruments to varying environmental conditions,...

Brett C. Bush; Francisco P. J. Valero; A. Sabrina Simpson; Lionel Bignone

2000-02-01T23:59:59.000Z

294

A statistical method for estimating wood thermal diffusivity and probe geometry using in situ heat response curves from sap flow measurements  

SciTech Connect

The heat pulse method is widely used to measure water flux through plants; it works by inferring the velocity of water through a porous medium from the speed at which a heat pulse is propagated through the system. No systematic, non-destructive calibration procedure exists to determine the site-specific parameters necessary for calculating sap velocity, e.g., wood thermal diffusivity and probe spacing. Such parameter calibration is crucial to obtain the correct transpiration flux density from the sap flow measurements at the plant scale; and consequently, to up-scale tree-level water fluxes to canopy and landscape scales. The purpose of this study is to present a statistical framework for estimating the wood thermal diffusivity and probe spacing simutaneously from in-situ heat response curves collected by the implanted probes of a heat ratio apparatus. Conditioned on the time traces of wood temperature following a heat pulse, the parameters are inferred using a Bayesian inversion technique, based on the Markov chain Monte Carlo sampling method. The primary advantage of the proposed methodology is that it does not require known probe spacing or any further intrusive sampling of sapwood. The Bayesian framework also enables direct quantification of uncertainty in estimated sap flow velocity. Experiments using synthetic data show that repeated tests using the same apparatus are essential to obtain reliable and accurate solutions. When applied to field conditions, these tests are conducted during different seasons and automated using the existing data logging system. The seasonality of wood thermal diffusivity is obtained as a by-product of the parameter estimation process, and it is shown to be affected by both moisture content and temperature. Empirical factors are often introduced to account for the influence of non-ideal probe geometry on the estimation of heat pulse velocity, and they are estimated in this study as well. The proposed methodology can be applied for the calibration of existing heat ratio sap flow systems at other sites. It is especially useful when an alternative transpiration calibration device, such as a lysimeter, is not available.

Chen, Xingyuan; Miller, Gretchen R.; Rubin, Yoram; Baldocchi, Dennis

2012-09-13T23:59:59.000Z

295

Estimating Liquid Fluxes in Thermally Perturbed Fractured Rock Using Measured Temperature Profiles  

DOE Green Energy (OSTI)

A new temperature-profile method was recently developed for analyzing perturbed flow conditions in superheated porous media. The method uses high-resolution temperature data to estimate the magnitude of the heat-driven liquid and gas fluxes that form as a result of boiling, condensation, and recirculation of pore water. In this paper, we evaluate the applicability of this new method to the more complex flow behavior in fractured formations with porous rock matrix. In such formations, with their intrinsic heterogeneity, the porous but low-permeable matrix provides most of the mass and heat storage capacity, and dominates conductive heat transfer, Fractures, on the other hand, offer highly effective conduits for gas and liquid flow, thereby generating significant convective heat transfer. After establishing the accuracy of the temperature-profile method for fractured porous formations, we apply the method in analyzing the perturbed flow conditions in a large-scale underground heater test conducted in unsaturated fractured porous tuff. The flux estimates for this test indicate a significant reflux of water near the heat source, on the order of a few hundred millimeter per year-much larger than the ambient percolation flux of only a few millimeter per year.

J.T. Birkholzer

2005-02-14T23:59:59.000Z

296

Measurements of Carbonaceous Aerosols using Semi-Continuous Thermal-Optical Method  

Science Conference Proceedings (OSTI)

Carbonaceous aerosols are major components in air pollution as a result of energy consumption, thus measurement of them is important to waste management. Increasing interest has been drawn to the identification, measurement, analysis, and modeling of carbon aerosols in the past decade. This book chapter will provide a review of current state-of-art techniques to determine carbonaceous aerosols in relation to air pollution and waste management. The chapter will be composed of four parts. The introduction will discuss why carbon aerosols including elemental carbon (EC), organic carbon (OC), and total carbon (TC=EC+OC) are important to energy consumption, air pollution, waste management, and global climate change. Key definitions will be introduced. Relevant terminologies will be provided. The second part will be a review of the current state-of the art measurement techniques that are used to determine carbon aerosols. Both on-line and off-line methods will be described. Comparisons of different techniques that provide the same physical quantity will be provided based on recent literature findings. Differences among the physical parameters determined by various techniques will be discussed. The third part will focus on data analysis and products obtained from carbon aerosol measurements. In addition to EC, OC, and TC, primary organic carbon (POC) and secondary organic carbon (SOC) are of interest to researchers to understand the source and sink of carbonaceous aerosols. Techniques used to determine POC and SOC, such as the EC tracer method and positive matrix factorization, will be described and their differences discussed. Examples will be provided showing field data comparison between the Sunset organic carbon and elemental carbon field analyzer and the Aerodyne aerosol mass spectrometer, both of which are widely used for on-line aerosol measurements. The last part will report new trends and summarize future research needs in carbon aerosol measurement. Emerging problems will be identified and research priorities will be recommended.

Yu, Xiao-Ying

2011-08-01T23:59:59.000Z

297

A Thermal Device for Aircraft Measurement of the Solid Water Content of Clouds  

Science Conference Proceedings (OSTI)

A constant temperature probe for the measurement of solid water content of clouds is described. The probe is operated at a temperature of approximately 25°C, and is designed to collect and melt ice particles that impact in an open half-cylinder, ...

W. D. King; D. E. Turvey

1986-09-01T23:59:59.000Z

298

Representative Air Temperature of Thermally Heterogeneous Urban Areas Using the Measured Pressure Gradient  

Science Conference Proceedings (OSTI)

A method to measure an area-averaged ground air temperature based on the hydrostatic equation is shown. The method was devised to overcome the problem of finding the most representative surface air temperature over a wide region, a problem that ...

Hirofumi Sugawara; Ken-ichi Narita; Takehiko Mikami

2004-08-01T23:59:59.000Z

299

Isotopic yield measurement in the heavy mass region for {sup 239}Pu thermal neutron induced fission  

SciTech Connect

Despite the huge number of fission yield data available in the different evaluated nuclear data libraries, such as JEFF-3.1.1, ENDF/B-VII.0, and JENDL-4.0, more accurate data are still needed both for nuclear energy applications and for our understanding of the fission process itself. It is within the framework of this that measurements on the recoil mass spectrometer Lohengrin (at the Institut Laue-Langevin, Grenoble, France) was undertaken, to determine isotopic yields for the heavy fission products from the {sup 239}Pu(n{sub th},f) reaction. In order to do this, a new experimental method based on {gamma}-ray spectrometry was developed and validated by comparing our results with those performed in the light mass region with completely different setups. Hence, about 65 fission product yields were measured with an uncertainty that has been reduced on average by a factor of 2 compared to that previously available in the nuclear data libraries. In addition, for some fission products, a strongly deformed ionic charge distribution compared to a normal Gaussian shape was found, which was interpreted as being caused by the presence of a nanosecond isomeric state. Finally, a nuclear charge polarization has been observed in agreement, with the one described on other close fissioning systems.

Bail, A.; Serot, O.; Mathieu, L.; Litaize, O.; Materna, T.; Koester, U.; Faust, H.; Letourneau, A.; Panebianco, S. [CEA, DEN-Cadarache, F-13108 Saint-Paul-lez-Durance (France); Institut Laue Langevin, 6 rue Jules Horowitz, B.P. 156, F-38042, Grenoble (France); CEA, DSM-Saclay, IRFU/SPhN, F-91191 Gif-sur-Yvette (France)

2011-09-15T23:59:59.000Z

300

Multilayer Nanoscale Thermal Barrier Coatings  

Science Conference Proceedings (OSTI)

Advanced high-efficiency gas turbines require thermal barrier coatings (TBCs) with low thermal conductivity and excellent thermal-cycling resistance. The multilayer TBC developed in this project has a thermal conductivity about half that of conventional TBCs and also rejects up to 70 percent of incoming radiant energy.

1999-05-26T23:59:59.000Z

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.


301

Measurement of plutonium and americium volatilities under thermal process conditions. Final report  

Science Conference Proceedings (OSTI)

We have used the transpiration method to measure volatilities of Pu and Am from PuO{sub 2}(s) and PuO{sub 2}/2% AmO{sub 2}(s) in the presence of steam and oxygen at temperatures of 1230--1430 K. We find the volatile species to be PuO{sub 2}(OH){sub 2}(g) and AmO{sub 2}(OH){sub 2}(g) at vapor pressures on the order of 10{sup {minus}10} atm and 10 {sup {minus}12} atm respectively under measurement conditions. For the Pu volatilization reaction, PuO{sub 2}(s) + 1/2 0{sub 2}(9) + H{sub 2}0(g) = PuO{sub 2}(OH){sub 2}(g), we obtain a free energy of reaction of {Delta}G{sup O}{sub T} = 231.3--0.0109 T in kj/mol, and for the Am volatilization reaction, AmO{sub 2}(s.s. in PuO{sub 2}) + 1/2 0{sub 2}(9) + H{sub 2}0(g) = AmO{sub 2}(OH){sub 2}(g), we obtain AG{sup O}{sub T} = 223.9--0.0109 T in kj/mol. We apply these results to the Rocky Flats Plant Fluidized Bed Incinerator to assess the amount of volatile Pu and Am produced in the secondary combustor chamber. Taking operating conditions of 550C combustor temperature, 40 kmols/h of total gas flow at 1 atm pressure, 0.1 atm 0{sub 2}(9), 0.05 atm H{sub 2}0(g), PuO{sub 2} (s) containing 200 ppm AmO{sub 2} in the bed, and 6000 h of operating time per year, gives volatilization rates of 7 {times} 10 {sup {minus}6}g Pu and 4 {times} 10 {sup {minus}9}g Am/y.

Krikorian, O.H.; Condit, R.H.; Fontes, A.S. Jr.; Fleming, D.L.; Magana, J.W.; Morris, W.F.; Adamson, M.G.

1993-04-28T23:59:59.000Z

302

Improved Thermal Properties of In Situ Formed Al/AlN Composites ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Thermal conduction and thermal expansion behaviors of heat sink materials are critical for microelectronic packaging because high thermal ...

303

Thermal Properties  

Science Conference Proceedings (OSTI)

Table 12   Thermal conductivities of polymers and other materials...40,000 2.8 Aluminum 24,000 1.7 Steel 5000 0.35 Granite 350 0.02 Crown glass (75 wt% silica) 90 0.006 Source: Ref 4...

304

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

305

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

Science Conference Proceedings (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

306

Activation Measurements for Thermal Neutrons, U.S. Measurements of 36Cl in Mineral Samples from Hiroshima and Nagasaki; and Measurement of 63 Ni in Copper Samples From Hiroshima by Accelerator Mass Spectrometry  

SciTech Connect

The present paper presents the {sup 36}Cl measurement effort in the US. A large number of {sup 36}Cl measurements have been made in both granite and concrete samples obtained from various locations and distances in Hiroshima and Nagasaki. These measurements employed accelerator mass spectrometry (AMS) to quantify the number of atoms of {sup 36}Cl per atom of total Cl in the sample. Results from these measurements are presented here and discussed in the context of the DS02 dosimetry reevaluation effort for Hiroshima and Nagasaki atomic-bomb survivors. The production of {sup 36}Cl by bomb neutrons in mineral samples from Hiroshima and Nagasaki was primarily via the reaction {sup 35}Cl(n,{gamma}){sup 36}Cl. This reaction has a substantial thermal neutron cross-section (43.6 b at 0.025 eV) and the product has a long half-life (301,000 y). hence, it is well suited for neutron-activation detection in Hiroshima and Nagasaki using AMS more than 50 years after the bombings. A less important reaction for bomb neutrons, {sup 39}K(n,{alpha}){sup 36}Cl, typically produces less than 10% of the {sup 36}Cl in mineral samples such as granite and concrete, which contain {approx} 2% potassium. In 1988, only a year after the publication of the DS86 final report (Roesch 1987), it was demonstrated experimentally that {sup 36}Cl measured using AMS should be able to detect the thermal neutron fluences at the large distances most relevant to the A-bomb survivor dosimetry. Subsequent measurements in mineral samples from both Hiroshima and Nagasaki validated the experimental findings. The potential utility of {sup 36}Cl as a thermal neutron detector in Hiroshima was first presented by Haberstock et al. who employed the Munich AMS facility to measure {sup 36}Cl/Cl ratios in a gravestone from near the hypocenter. That work subsequently resulted in an expanded {sup 36}Cl effort in Germany that paralleled the US work. More recently, there have also been {sup 36}Cl measurements made by a Japanese group. The impetus for the extensive {sup 36}Cl and other neutron activation measurements was the recognized need to validate the neutron component of the dose in Hiroshima. Although this was suggested at the time of the DS86 Final Report, where it was stated that the calculated neutron doses for survivors could possibly be wrong, the paucity of neutron validation measurements available at that time prevented adequate resolution of this matter. It was not until additional measurements and data evaluations were made that it became clear that more work was required to better understand the discrepancies observed for thermal neutrons in Hiroshima. This resulted in a large number of additional neutron activation measurements in Hiroshima and Nagasaki by scientists in the US, Japan, and Germany. The results presented here for {sup 36}Cl, together with measurements made by other scientists and for other isotopes, now provide a much improved measurement basis for the validation of neutrons in Hiroshima.

Tore Straume; Alfredo A. Marchetti; Stephen D. Egbert; James A. Roberts; Ping Men; Shoichiro Fujita; Kiyoshi Shizuma; Masaharu Hoshi; G. Rugel; W. Ruhm; G. Korschinek; J. E. McAninch; K. L. Carroll; T. Faestermann; K. Knie; R. E. Martinelli; A. Wallner; C. Wallner

2005-01-14T23:59:59.000Z

307

Evaluation of the thermal resistance of a roof-mounted multi-reflective radiant barrier for tropical and humid conditions: Experimental study from field measurements  

E-Print Network (OSTI)

This paper deals with the experimental evaluation of a roof-mounted multi-reflective radiant barrier (MRRB), installed according to the state of the art, on a dedicated test cell. An existing experimental device was completed with a specific system for the regulation of the airflow rate in the upper air layer included in a typical roof from Reunion Island. Several experimental sequences were conducted to determine the thermal resistance of the roof according to several parameters and following a specific method. The mean method, well known in international standards (ISO 9869 - 1994) for the determination of the thermal resistance using dynamic data, was used. The method was implemented in a building simulation code in order to allow the determination of the thermal indicator automatically. Experimental results are proposed according to different seasonal periods and for different values of the airflow rate in the upper air layer.

Frédéric Miranville; Ali Hamada Fakra; Stéphane Guichard; Harry Boyer; Jean Philippe Praene; Dimitri Bigot

2012-12-19T23:59:59.000Z

308

Evaluation of the thermal resistance of a roof-mounted multi-reflective radiant barrier for tropical and humid conditions: Experimental study from field measurements  

E-Print Network (OSTI)

This paper deals with the experimental evaluation of a roof-mounted multi-reflective radiant barrier (MRRB), installed according to the state of the art, on a dedicated test cell. An existing experimental device was completed with a specific system for the regulation of the airflow rate in the upper air layer included in a typical roof from Reunion Island. Several experimental sequences were conducted to determine the thermal resistance of the roof according to several parameters and following a specific method. The mean method, well known in international standards (ISO 9869 - 1994) for the determination of the thermal resistance using dynamic data, was used. The method was implemented in a building simulation code in order to allow the determination of the thermal indicator automatically. Experimental results are proposed according to different seasonal periods and for different values of the airflow rate in the upper air layer

Miranville, Frédéric; Guichard, Stéphane; Boyer, Harry; Praene, Jean Philippe; Bigot, Dimitri

2012-01-01T23:59:59.000Z

309

Conducting fiber compression tester  

DOE Patents (OSTI)

The invention measures the resistance across a conductive fiber attached to a substrate place under a compressive load to determine the amount of compression needed to cause the fiber to fail. 3 figs.

DeTeresa, S.J.

1989-12-07T23:59:59.000Z

310

Variable pressure thermal insulating jacket  

DOE Patents (OSTI)

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

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

1994-01-01T23:59:59.000Z

311

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

312

Conduction cooling: multicrate fastbus hardware  

SciTech Connect

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

313

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

Science Conference Proceedings (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

314

Thermal Inertia of Conductivity Cells: Theory  

Science Conference Proceedings (OSTI)

The temperature anomaly of a fluid moving through circular and rectangular cylinders induced by the heat stored in the walls of these hollow cylinders is derived under the assumption of quasi-steady heat transfer. These geometries correspond ...

Rolf G. Lueck

1990-10-01T23:59:59.000Z

315

Viscosity and Thermal Conductivity Equations for Nitrogen ...  

Science Conference Proceedings (OSTI)

... that both could be used as reference equations for ... the National Institute of Standards and Technology (NIST). ... of state for air as a pseudo-pure fluid. ...

2004-04-05T23:59:59.000Z

316

Thermal Conductivity of Liquids and Gases  

Science Conference Proceedings (OSTI)

... JCED Supporting Information: Propane.(ASCII)(pdf)(Postscript). JCED Supporting Information: Butane.(ASCII)(pdf)(Postscript). ...

2006-10-31T23:59:59.000Z

317

Thermal Conductivity of Polycrystalline Semiconductors and Ceramics  

E-Print Network (OSTI)

industries, polycrystalline semiconductors and ceramics havelaser industry, people are also seeking good ceramic laser

Wang, Zhaojie

2012-01-01T23:59:59.000Z

318

Reduced Thermal Conductivity of Compacted Silicon Nanowires  

E-Print Network (OSTI)

Nanoscale Heat Transfer Processes …. ………………………………. 7 1.4:1.3 – Nanoscale Heat Transfer Processes When studying heat

Yuen, Taylor S.

319

Computational Design of Low Thermal Conductivity TBC ...  

Science Conference Proceedings (OSTI)

Page 1. Edwin R. Fuller, Jr., National Institute of Standards and Technology Gaithersburg, MD 20899 Yougen Yang, Derek D. Hass, and Haydn NG ...

2004-05-17T23:59:59.000Z

320

Thermal Conductivity for a Linear Anharmonic System  

SciTech Connect

A model has been proposed wherein self consistent phonon theory together with the thermodynamic perturbation theory is employed to determine a trial Hamiltonian is employed to determine thermodynamic parameters based on pining as well as nearest neighbor quadratic-quartic interactions.

Pasrija, Ritu [Department of Physics, DAV College, Abohar-152116 (India); Kanika [Dasmesh Girls College, Badal (Muktsar)-152113 (India); Srivastava, Sunita [Deparment of Physics, Panjab University Chandigarh-160014 (India)

2011-07-15T23:59:59.000Z

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.


321

Microstructure and Thermal Conductivity of Hydrated Calcium ...  

Science Conference Proceedings (OSTI)

... the above-mentioned temperature gradients, the effect of the 150 °C temperature gradient is not ... Journal of Volcanology and Geothermal Research. ...

2007-05-02T23:59:59.000Z

322

Conductive Polymers  

DOE Green Energy (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

323

thermal_resistance_measurements  

Science Conference Proceedings (OSTI)

... "The NBS Line-Heat-Source Guarded Hot Plate for Thick Materials",FJ Powell and BG Rennex, Proceedings ASHRAE/DOE Conference - II, Atlanta ...

2013-12-16T23:59:59.000Z

324

Characterization of Thermal Properties of Depleted Uranium Metal Microspheres  

E-Print Network (OSTI)

Nuclear fuel comes in many forms; oxide fuel is the most commonly used in current reactor systems while metal fuel is a promising fuel type for future reactors due to neutronic performance and increased thermal conductivity. As a key heat transfer parameter, thermal conductivity describes the heat transport properties of a material based upon the density, specific heat, and thermal diffusivity. A material’s ability to transport thermal energy through its structure is a measurable property known as thermal diffusivity; the units for thermal diffusivity are given in area per unit time (e.g., m2/s). Current measurement methods for thermal diffusivity include LASER (or light) Flash Analysis and the hot-wire method. This study examines an approach that combines these previous two methods to characterize the diffusivity of a packed bed of microspheres of depleted uranium (DU) metal, which have a nominal diameter of 250 micrometers. The new apparatus is designated as the Crucible Heater Test Assembly (CHTA), and it induces a radial transient across a packed sample of microspheres then monitors the temperature profile using an array of thermocouples located at different distances from the source of the thermal transient. From the thermocouple data and an accurate time log, the thermal diffusivity of the sample may be calculated. Results indicate that DU microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer. At 500°C, the thermal conductivity of the DU microspheres was 0.431 ± 13% W/m-K compared to approximately 32 W/m-K for solid uranium metal. Characterization of the developed apparatus revealed a method that may be useful for measuring the thermal diffusivity of powders and liquids.

Humrickhouse, Carissa Joy

2012-05-01T23:59:59.000Z

325

Evaluation of Water Stress Impact on the Parameter Values in Stomatal Conductance Models Using Tower Flux Measurement of a Boreal Aspen Forest  

Science Conference Proceedings (OSTI)

The impact of water stress on plant stomatal conductance (g) has been widely studied but with little consensus as to the processes governing its responses. The photosynthesis-driven stomatal conductance models usually employ constant model ...

Shusen Wang

2012-02-01T23:59:59.000Z

326

Thermal Diffusivity and Thermal Conductivity of HLW and LAW ...  

Science Conference Proceedings (OSTI)

In the present work, such data were collected for four waste glasses representative of those currently projected for treatment of Hanford HLW and LAW streams.

327

Polarization of Thermal Microwave Atmospheric Radiation Due to Scattering by Ice Particles in Clouds  

Science Conference Proceedings (OSTI)

The polarization difference ?Tb between the vertical and horizontal components of thermal radiation emitted by clouds was studied using 37- and 85-GHz radiometers. The measurements were conducted during the Alliance Icing Research Project in ...

A. V. Troitsky; A. M. Osharin; A. V. Korolev; J. W. Strapp

2003-07-01T23:59:59.000Z

328

THERMAL PROPERTIES OF FIBERBOARD OVERPACK MATERIALS IN THE 9975 SHIPPING PACKAGE  

DOE Green Energy (OSTI)

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

VORMELKER, PHILLIP; DAUGHERTY, W. L.

2005-06-10T23:59:59.000Z

329

Device for thermal transfer and power generation  

SciTech Connect

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

330

Measurement of thermal neutron cross section and resonance integral for the {sup 170}Er(n,{gamma}){sup 171}Er reaction by using a {sup 55}Mn monitor  

Science Conference Proceedings (OSTI)

The thermal neutron cross section and the resonance integral of the reaction {sup 170}Er(n,{gamma}){sup 171}Er were measured by the Cd-ratio method using a {sup 55}Mn monitor as single comparator. Analytical grade MnO{sub 2} and Er{sub 2}O{sub 3} powder samples with and without a cylindrical 1 mm Cd shield box were irradiated in an isotropic neutron field obtained from three {sup 241}Am-Be neutron sources. The induced activities in the samples were measured with a 120.8% relative efficiency p-type HPGe detector. The correction factors for gamma-ray attenuation (F{sub g}), thermal neutron self-shielding (G{sub th}), and resonance neutron self-shielding (G{sub epi}) effects, and the epithermal neutron spectrum shape factor ({alpha}) were taken into account. The thermal neutron cross section for the (n,{gamma}) reaction in {sup 170}Er has been determined to be 8.00 {+-} 0.56 b, relative to that of the {sup 55}Mn monitor. However, some previously reported experimental results compared to the present result show a large discrepancy ranging from 8.3 to 86%. The present result is, in general, in good agreement with the recently measured values by 9%. According to the definition of Cd cut-off energy at 0.55 eV, the resonance integral obtained is 44.5 {+-} 4.0 b, which is determined relative to the reference integral value of the {sup 55}Mn monitor by using cadmium ratios. The existing experimental data for the resonance integral are distributed between 18 and 43 b. The present resonance integral value agrees only with the measurement of 43 {+-} 5 b by Gillette [Thermal Cross Section and Resonance Integral Studies, ORNL-4155, 15 (1967)] within uncertainty limits.

Yuecel, Haluk [Turkish Atomic Energy Authority (TAEK), Besevler Campus, 06100 Tandogan-Ankara (Turkey); Budak, M. Gueray; Karadag, Mustafa [Gazi University, Gazi Education Faculty, 06500 Teknikokullar-Ankara (Turkey)

2007-09-15T23:59:59.000Z

331

Electrical and thermal properties of graphite/polyaniline composites  

SciTech Connect

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

332

Thermal performance measurements of sealed insulating glass units with low-E coatings using the MoWiTT (Mobile Window Thermal Test) field-test facility  

SciTech Connect

Using data obtained in a mobile field-test facility, measured performance of clear and low-emissivity double-glazing units is presented for south-facing and north-facing orientations. The changes in U-value and shading coefficient resulting from addition of the low-E coating are found to agree with theoretical expectations for the cold spring test conditions. Accurate nighttime U-values were derived from the data and found to agree with calculations. Expected correlation between U-value and wind speed was not observed in the data; a plausible experimental reason for this is advanced.

Klems, J.; Keller, H.

1986-12-01T23:59:59.000Z

333

A High-Accuracy Multiwavelength Radiometer for In Situ Measurements in the Thermal Infrared. Part II: Behavior in Field Experiments  

Science Conference Proceedings (OSTI)

The performances of the new conveyable low-noise infrared radiometer for measurements of atmosphere and ground surface targets, or CLIMAT, are presented for in situ measurements. For this, quantitative analyses were carried out on measurements ...

Gérard Brogniez; Christophe Pietras; Michel Legrand; Philippe Dubuisson; Martial Haeffelin

2003-07-01T23:59:59.000Z

334

Thermal imaging diagnostics of high-current electron beams  

SciTech Connect

The thermal imaging diagnostics of measuring pulsed electron beam energy density is presented. It provides control of the electron energy spectrum and a measure of the density distribution of the electron beam cross section, the spatial distribution of electrons with energies in the selected range, and the total energy of the electron beam. The diagnostics is based on the thermal imager registration of the imaging electron beam thermal print in a material with low bulk density and low thermal conductivity. Testing of the thermal imaging diagnostics has been conducted on a pulsed electron accelerator TEU-500. The energy of the electrons was 300-500 keV, the density of the electron current was 0.1-0.4 kA/cm{sup 2}, the duration of the pulse (at half-height) was 60 ns, and the energy in the pulse was up to 100 J. To register the thermal print, a thermal imager Fluke-Ti10 was used. Testing showed that the sensitivity of a typical thermal imager provides the registration of a pulsed electron beam heat pattern within one pulse with energy density over 0.1 J/cm{sup 2} (or with current density over 10 A/cm{sup 2}, pulse duration of 60 ns and electron energy of 400 keV) with the spatial resolution of 0.9-1 mm. In contrast to the method of using radiosensitive (dosimetric) materials, thermal imaging diagnostics does not require either expensive consumables, or plenty of processing time.

Pushkarev, A.; Kholodnaya, G.; Sazonov, R.; Ponomarev, D. [Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

2012-10-15T23:59:59.000Z

335

Mechanical and thermal design of the CEBAF Hall a beam calorimeter  

SciTech Connect

A calorimeter is being fabricated to provide 0.5% - 1.0% absolute measurement of the beam current in the Hall A end station of the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLAB). Modern powder metallurgy processes have produced high density, high thermal conductivity tungsten-copper composite materials that minimize electromagnetic and hadronic energy loss while maintaining a rapid thermal response time. Heat leaks are minimized by mounting the mass in vacuum on glass ceramic mounts. A conduction cooling scheme utilizes an advanced carbon fiber compliant thermal interface material. Transient finite difference and finite element models were developed to estimate heat leaks and thermal response times.

M. Bevins; A. Day; P. Degtiarenko; L.A. Dillon-Townes; A. Freyberger; R. Gilman; A. Saha; S. Slachtouski

2005-05-16T23:59:59.000Z

336

Field Studies of Subjective Effects on Thermal Comfort in a University Classroom  

E-Print Network (OSTI)

Two field studies were conducted in a university classroom in the autumn of 2004 in Harbin. The objective of these studies was to assess the thermal conditions and the subjective effects on occupant thermal comfort. A field study was carried out when the undergraduate students were not taught the theory of thermal comfort. A second study was conducted after the undergraduate students knew something about thermal comfort. The thermal comfort variables were measured when the students were filling in the subjective questionnaires on thermal sensation and thermal comfort. A total of 167 sets of questionnaire responses were obtained. The indoor thermal environmental data for the two days are almost the same; however the thermal acceptability is different. The acceptability of the first study is 96.0%, which is higher than the acceptability of 91.5% according to the PPD. In contrast, the acceptability of the second study is 57.4%, which is very low compared with the acceptability of 95.0% according to the PPD. The students' thermal acceptability of the thermal environment before learning the theory of thermal comfort is higher than after learning about thermal comfort. These results confirm the existence of subjective effects on thermal comfort.

Wang, J.; Wang, Z.

2006-01-01T23:59:59.000Z

337

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

338

A thermal comfort levels investigation of a naturally ventilated and air-conditioned office  

Science Conference Proceedings (OSTI)

The purpose of this study is to investigate thermal comfort levels of a naturally ventilated and air-conditioner office. Field experiments conducted in an office room in Universiti Putra Malaysia (UPM) used survey questionnaires and physical measurements. ... Keywords: PMV, mechanically ventilation, naturally ventilated, neutral temperature, objective study, subjective approach, thermal comfort

R. Daghigh; N. M. Adam; K. Sopian; A. Zaharim; B. B. Sahari

2008-09-01T23:59:59.000Z

339

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

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

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

340

Thermally activated miniaturized cooling system.  

E-Print Network (OSTI)

??A comprehensive study of a miniaturized thermally activated cooling system was conducted. This study represents the first work to conceptualize, design, fabricate and successfully test… (more)

Determan, Matthew Delos

2008-01-01T23:59:59.000Z

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


341

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

342

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

343

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

344

A High-Accuracy Multiwavelength Radiometer for In Situ Measurements in the Thermal Infrared. Part I: Characterization of the Instrument  

Science Conference Proceedings (OSTI)

The new infrared radiometer (conveyable low-noise infrared radiometer for measurements of atmosphere and ground surface targets, or CLIMAT) is a highly sensitive field instrument designed to measure brightness temperatures or radiances in the ...

Michel Legrand; Christophe Pietras; Gérard Brogniez; Martial Haeffelin; Nader Khalil Abuhassan; Michaël Sicard

2000-09-01T23:59:59.000Z

345

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

SciTech Connect

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

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

2010-12-15T23:59:59.000Z

346

The Charge Induced on a Conducting Cylinder by a Point Charge and Its Application to the Measurement of Charge on Precipitation  

Science Conference Proceedings (OSTI)

The solution of the electrostatic boundary value problem for a point charge inside an infinite cylinder is applied to sensors employed in the measurement of charge on precipitation. With these devices the charge induced on a cylindrical segment ...

Andrew J. Weinheimer

1988-04-01T23:59:59.000Z

347

Pressure Measurements in a PBX 9501 Gauged Acceptor When Impacted by a Steel Plate that is Accelerated by a Thermally Cooked Off PBX 9501 Charge  

DOE Green Energy (OSTI)

Measuring the violence of a thermal explosion of a cased explosive is important for evaluating safety issues of explosive devices in fires. A sympathetic initiation scenario was studied here where a 9.0 cm diameter by 2.5 cm thick disc of PBX 9501 donor charge encased in a 304 stainless steel assembly was heated on top and bottom flat surfaces until it thermally exploded. The initial heating rate at the metal/explosive interface was 5 C per minute until it reaches 170 C; then this temperature is held for 35 minutes to allow temperature equilibration to within a few degrees throughout the explosive. The heating resumed at a rate of 1 C per minute until the PBX 9501 donor thermally exploded. A PBX 9501 acceptor charge with carbon resistor and manganin foil pressure gauges inserted at various depths was placed at a 10 cm standoff distance from the donor charge's top steel cover plate. Piezoelectric arrival time pins were placed in front of the acceptor surface to measure the velocity and shape of the impacting plate. The stainless steel cover plate of the donor charge had a nominal velocity of 0.55 {+-} 0.04 mm/{micro}s upon impact and was non-symmetrically warped. The impact of the tilted curved plate induced a three-dimensional compression wave into the acceptor. The rise times of the pressure waves were nominally 1.5 {micro}s with the closest carbon resistor gauges giving peak pressure of 10 kb that decayed to 3 kb for a wave run distance of 2.4 cm.

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

2002-03-11T23:59:59.000Z

348

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

349

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

Science Conference Proceedings (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

350

Conduction and Moisture Diffusion  

Science Conference Proceedings (OSTI)

Table 2   Equivalent physical quantities...conduction Temperature Temperature gradient Heat flux Heat conductivities Resistivities Electric conduction Electric potential Electric field intensity Current density Electric conductivities Resistivities Electrostatics Electric potential Electric field intensity Electric induction, electric...

351

Sampling artifacts from conductive silicone tubing  

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

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

352

Concrete Electrical Conductivity Test  

Science Conference Proceedings (OSTI)

Concrete Electrical Conductivity Test. Description/Summary: ... Details. Type of software: Virtual concrete electrical conductivity test. Authors: ...

2013-06-11T23:59:59.000Z

353

Solution Processing of Polymer Nanotube Thermal Interface Materials  

Science Conference Proceedings (OSTI)

Ideal TIMs should exhibit high thermal conductivity and maintain mechanical ... bulk polymers exhibit phonon scattering and are poor conductors of thermal ...

354

Aluminum/TPG Metal Matrix Composite with Improved Thermal ...  

Science Conference Proceedings (OSTI)

It was found that A356/TPG interface was optimal for the examined MMC's high thermal conductivity. Low cooling rates assisted in reducing thermal stresses at ...

355

THERMAL RECOVERY  

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

THERMAL RECOVERY Thermal recovery comprises the techniques of steamflooding, cyclic steam stimulation, and in situ combustion. In steamflooding, high-temperature steam is injected...

356

Thermal properties of PZT95/5(1.8Nb) and PSZT ceramics.  

SciTech Connect

Thermal properties of niobium-modified PZT95/5(1.8Nb) and PSZT ceramics used for the ferroelectric power supply have been studied from -100 C to 375 C. Within this temperature range, these materials exhibit ferroelectric-ferroelectric and ferroelectric-paraelectric phase transformations. The thermal expansion coefficient, heat capacity, and thermal diffusivity of different phases were measured. Thermal conductivity and Grueneisen constant were calculated at several selected temperatures between -60 C and 100 C. Results show that thermal properties of these two solid solutions are very similar. Phase transformations in these ceramics possess first order transformation characteristics including thermal hysteresis, transformational strain, and enthalpy change. The thermal strain in the high temperature rhombohedral phase region is extremely anisotropic. The heat capacity for both materials approaches to 3R (or 5.938 cal/(g-mole*K)) near room temperature. The thermal diffusivity and the thermal conductivity are quite low in comparison to common oxide ceramics, and are comparable to amorphous silicate glass. Furthermore, the thermal conductivity of these materials between -60 C and 100 C becomes independent of temperature and is sensitive to the structural phase transformation. These phenomena suggest that the phonon mean free path governing the thermal conductivity in this temperature range is limited by the lattice dimensions, which is in good agreement with calculated values. Effects of small compositional changes and density/porosity variations in these ceramics on their thermal properties are also discussed. The implications of these transformation characteristics and unusual thermal properties are important in guiding processing and handling procedures for these materials.

DiAntonio, Christopher Brian; Rae, David F.; Corelis, David J.; Yang, Pin; Burns, George Robert

2006-11-01T23:59:59.000Z

357

National Solar Thermal Test Facility  

SciTech Connect

This is a brief report about a Sandia National Laboratory facility which can provide high-thermal flux for simulation of nuclear thermal flash, measurements of the effects of aerodynamic heating on radar transmission, etc

Cameron, C.P.

1989-12-31T23:59:59.000Z

358

Comments on “Estimating Soil Water Contents from Soil Temperature Measurements by Using an Adaptive Kalman Filter”  

Science Conference Proceedings (OSTI)

A scheme was proposed by Zhang et al. to estimate soil water content from soil temperature measurements by using an adaptive Kalman filter. Their scheme is based on the fact that soil heat capacity and thermal conductivity are a monotonic ...

Kun Yang; Toshio Koike

2005-04-01T23:59:59.000Z

359

Assembly and testing of a composite heat pipe thermal intercept for HTS current leads  

SciTech Connect

We are building high temperature superconducting (HTS) current leads for a demonstration HTS-high gradient magnetic separation (HGMS) system cooled by a cryocooler. The current leads are entirely conductively cooled. A composite nitrogen heat pipe provides efficient thermal communication, and simultaneously electrical isolation, between the lead and an intermediate temperature heat sink. Data on the thermal and electrical performance of the heat pipe thermal intercept are presented. The electrical isolation of the heat pipe was measured as a function of applied voltage with and without a thermal load across the heat pipe. The results show the electrical isolation with evaporation, condensation and internal circulation taking place in the heat pipe.

Daugherty, M.A.; Daney, D.E.; Prenger, F.C.; Hill, D.D.; Williams, P.M.; Boenig, H.J.

1995-09-01T23:59:59.000Z

360

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

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

High-Efficiency Thermal Energy Storage System for CSP  

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

June 15, 2013 | Singh * Thermal modeling will be conducted to establish the benefits of using a high thermal conducting graphite foams in conjunction with PCM and to develop a...

362

Determining effective soil formation thermal properties from field data using a parameter estimation technique  

DOE Green Energy (OSTI)

A one-dimensional thermal model is derived to describe the temperature field around a vertical borehole heat exchanger (BHEx) for a geothermal heat pump. The inlet and outlet pipe flows are modeled as one, and an effective heat capacity is added to model the heat storage in the fluid and pipes. Parameter estimation techniques are then used to estimate various parameters associated with the model, including the thermal conductivity of the soil and of the grout which fills the borehole and surrounds the u-tube. The model is validated using test data from an experimental rig containing sand with known thermal conductivity. The estimates of the sand thermal conductivity derived from the model are found to be in good agreement with independent measurements.

Shonder, J.A. [Oak Ridge National Lab., TN (United States); Beck, J.V. [Michigan State Univ., East Lansing, MI (United States)

1998-11-01T23:59:59.000Z

363

Preliminary requirements for thermal storage subsystems in solar thermal applications  

DOE Green Energy (OSTI)

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

Copeland, R.J.

1980-04-01T23:59:59.000Z

364

Fractography of Thermally Shocked Glass Cookware  

Science Conference Proceedings (OSTI)

Fractography of fractured glass cookware can be a time consuming process of putting ... to Conduct Thermal Shock Test on Refractories Using Steel Blocks.

365

Definition: Thermal Rating | Open Energy Information  

Open Energy Info (EERE)

Rating Jump to: navigation, search Dictionary.png Thermal Rating The maximum amount of electrical current that a transmission line or electrical facility can conduct over a...

366

Thermal Management Using Carbon Nanotubes - Energy Innovation ...  

Patent 7,763,353: Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites Methods and apparatus are described for ...

367

Electromagnetic Alteration of Hydraulic Conductivity of Soils.  

E-Print Network (OSTI)

??Hydraulic conductivity is a measure of the rate at which water flows through porous media. Because of the dipole properties of water molecules, any electric… (more)

Azad, Sahba

2013-01-01T23:59:59.000Z

368

Code of Conduct  

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

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

369

Control of Test Conduct  

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

2 Revision 1 Effective June 2008 Control of Test Conduct Prepared by Electric Transportation Applications Prepared by: Date: Garrett P....

370

Majorana Demonstrator Bolted Joint Mechanical and Thermal Analysis  

SciTech Connect

The MAJORANA DEMONSTRATOR is designed to probe for neutrinoless double-beta decay, an extremely rare process with a half-life in the order of 1026 years. The experiment uses an ultra-low background, high-purity germanium detector array. The germanium crystals are both the source and the detector in this experiment. Operating these crystals as ionizing radiation detectors requires having them under cryogenic conditions (below 90 K). A liquid nitrogen thermosyphon is used to extract the heat from the detectors. The detector channels are arranged in strings and thermally coupled to the thermosyphon through a cold plate. The cold plate is joined to the thermosyphon by a bolted joint. This circular plate is housed inside the cryostat can. This document provides a detailed study of the bolted joint that connects the cold plate and the thermosyphon. An analysis of the mechanical and thermal properties of this bolted joint is presented. The force applied to the joint is derived from the torque applied to each one of the six bolts that form the joint. The thermal conductivity of the joint is measured as a function of applied force. The required heat conductivity for a successful experiment is the combination of the thermal conductivity of the detector string and this joint. The thermal behavior of the joint is experimentally implemented and analyzed in this study.

Aguayo Navarrete, Estanislao; Reid, Douglas J.; Fast, James E.

2012-06-01T23:59:59.000Z

371

Thermal Performance of Poly Alpha Olefin Nanofluid with Spherical and Non-spherical Nanoparticles  

E-Print Network (OSTI)

Research on nanofluids has been undertaken for several years because of the reported enhancements of thermal properties such as thermal conductivity and enhanced heat transfer performance in laminar flow. Nanofluid is the fluid where nanoparticles are dispersed in a base fluid. Thermal conductivity and viscosity are considered to be the most prominent factors in the efficient use of nanofluids. A change in thermal conductivity and viscosity also changes the convective heat transfer coefficient. Nanoparticles can be metallic or non-metallic and also can have different shapes. In this study, Poly-Alpha-Olefin (PAO) has been used as a base fluid with Alumina (Al2O3) nanoparticles. Poly-Alpha-Olefin is commonly used for engine lubrication in military applications and cooling in electronic and industrial devices. Several nanofluid samples were made by METSS Corp. in Ohio, USA using different dispersants, different base fluids and different morphology of alumina nanoparticles. The mass fraction of nanoparticles is from 2.5 to 20 percent. The thermal properties of each sample such as thermal conductivity and viscosity have been measured. Thermal conductivity of nanofluids and pure base fluids were both measured and the thermal conductivity enhancement has been calculated. Also, the heat transfer coefficient has been determined for laminar flow under constant heat flux conditions. Results indicate that all the tested nanofluids and base fluid samples show a Newtonian behavior. Among the nanofluid samples, NF-048, which contains non-spherical Alumina nanoparticles exhibits the greatest thermal conductivity enhancement when compared to pure PAO. Heat transfer tests were conducted with pure PAO and NF-048, and an enhancement in convective heat transfer coefficient was observed. The thermal conductivity of NF-048 increases with temperature, which is consistent with heat transfer results. Furthermore, the percentage enhancement in convective heat transfer coefficient was shown to increase non-linearly with the axial distance in the heat transfer section. NF-048 exhibits a lower Re (Reynolds number)*Ra (Rayleigh number) than pure PAO under laminar flow constant heat flux conditions indicating that nanoparticle morphology and composition are the two main factors responsible for convective heat transfer enhancement at low Reynolds number.

Park, Chan Hyun

2011-05-01T23:59:59.000Z

372

CONDUCT OF OPERATIONS (CO)  

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

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

373

The hydraulic conductivity of chopped sorghum  

Science Conference Proceedings (OSTI)

Hydraulic conductivity of water through chopped sweet sorghum at various packing densities and soaking times was measured using permeameters. Hydraulic conductivity decreased by two orders of magnitude as packing density increased from 400 to 897 kg/m/sup 3/. Soaking time had less effect on hydraulic conductivity, and the effect depended on packing density.

Custer, M.H.; Reddell, D.L.; Sweeten, J.M.

1987-01-01T23:59:59.000Z

374

Solar Thermal Conversion  

DOE Green Energy (OSTI)

The thermal conversion process of solar energy is based on well-known phenomena of heat transfer (Kreith 1976). In all thermal conversion processes, solar radiation is absorbed at the surface of a receiver, which contains or is in contact with flow passages through which a working fluid passes. As the receiver heats up, heat is transferred to the working fluid which may be air, water, oil, or a molten salt. The upper temperature that can be achieved in solar thermal conversion depends on the insolation, the degree to which the sunlight is concentrated, and the measures taken to reduce heat losses from the working fluid.

Kreith, F.; Meyer, R. T.

1982-11-01T23:59:59.000Z

375

Umklapp Scattering and Heat Conductivity of Superlattices  

E-Print Network (OSTI)

The mean free path of phonons in superlattices is estimated. It is shown to be strongly dependent on the superlattice period due to the Umklapp scattering in subbands. It first falls with increasing the superlattice period until it becomes comparable with the latter after what it rises back to the bulk value. Similar behavior is expected of heat conductivity, which is proportional to the mean free path. Superlattices offer an opportunity to control physical properties in unprecedented ways. Their thermal conductivity is of interest both for a fundamental understanding of these systems as well as in applications. Recently there has been a resurgence of interest in finding materials with improved thermoelectric transport properties for cooling and power generation. The quality of a material for such applications is given by the thermoelectric figure of merit, which is inversely proportional to the thermal conductivity ?. In materials of interest, such as semiconductors, the lattice contribution to ? dominates. Experimental and theoretical work suggests that the thermal conductivity of superlattices is quite low, both for transport along the planes [1, 2, 10], or perpendicular to the planes [3, 4, 5, 6, 7, 8, 11]. The lattice heat conductivity ? is given approximately by an equation [12]:

M. V. Simkin; G. D. Mahan

2000-01-01T23:59:59.000Z

376

High conductance surge cable  

DOE Patents (OSTI)

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

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

1998-12-08T23:59:59.000Z

377

Research Conduct Policies  

Office of Science (SC) Website

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

378

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

E-Print Network (OSTI)

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

Henry, Asegun

379

Nitrogen heat pipe for cryocooler thermal shunt  

SciTech Connect

A nitrogen heat pipe was designed, built and tested for the purpose of providing a thermal shunt between the two stages of a Gifford-McMahan (GM) cryocooler during cooldown. The nitrogen heat pipe has an operating temperature range between 63 and 123 K. While the heat pipe is in the temperature range during the system cooldown, it acts as a thermal shunt between the first and second stage of the cryocooler. The heat pipe increases the heat transfer to the first stage of the cryocooler, thereby reducing the cooldown time of the system. When the heat pipe temperature drops below the triple point, the nitrogen working fluid freezes, effectively stopping the heat pipe operation. A small heat leak between cryocooler stages remains because of axial conduction along the heat pipe wall. As long as the heat pipe remains below 63 K, the heat pipe remains inactive. Heat pipe performance limits were measured and the optimum fluid charge was determined.

Prenger, F.C.; Hill, D.D.; Daney, D.E.; Daugherty, M.A. [Los Alamos National Lab., NM (United States); Green, G.F.; Roth, E.W. [Naval Surface Warfare Center, Annapolis, MD (United States)

1995-09-01T23:59:59.000Z

380

Electrically conductive diamond electrodes  

DOE Patents (OSTI)

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

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

2009-05-19T23:59:59.000Z

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


381

Thermal Transport in Graphene Nanostructures: Experiments and Simulations Luis A. Jaureguia,b  

E-Print Network (OSTI)

to the high value of thermal conductivity measured on graphene, it has great promise in potential applications mechanically exfoliated from highly ordered pyrolytic graphite (HOPG), using scotch tapes (1). Graphene of graphene and silicon. The solid lines are the best linear fitting results, and the slopes are 4

Chen, Yong P.

382

Thermal regimes of Malaysian sedimentary basins  

Science Conference Proceedings (OSTI)

Properly corrected and calibrated thermal data are important in estimating source-rock maturation, diagenetics, evolution of reservoirs, pressure regimes, and hydrodynamics. Geothermal gradient, thermal conductivity, and heat flow have been determined for the sedimentary succession penetrated by exploratory wells in Malaysia. Geothermal gradient and heat-flow maps show that the highest average values are in the Malay Basin. The values in the Sarawak basin are intermediate between those of the Malay basin and the Sabah Basin, which contains the lowest average values. Temperature data were analyzed from more than 400 wells. An important parameter that was studied in detail is the circulation time. The correct circulation time is essential in determining the correct geothermal gradient of a well. It was found that the most suitable circulation time for the Sabah Basin is 20 hr, 30 hr for the Sarawak Basin and 40 hr for the Malay Basin. Values of thermal conductivity, determined from measurement and calibrated calculations, were grouped according to depositional units and cycles in each basin.

Abdul Halim, M.F. (Petronas Research and Scientific Services, Selangor (Malaysia))

1994-07-01T23:59:59.000Z

383

Thermal and non-thermal energies in solar flares  

E-Print Network (OSTI)

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

Pascal Saint-Hilaire; Arnold O. Benz

2005-03-03T23:59:59.000Z

384

Thermal insulated glazing unit  

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

385

Thermal insulated glazing unit  

DOE Patents (OSTI)

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

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

1988-04-05T23:59:59.000Z

386

Graphene nanoribbon conductance model in parabolic band structure  

Science Conference Proceedings (OSTI)

Many experimental measurements have been done on GNR conductance. In this paper, analytical model of GNR conductance is presented. Moreover, comparison with published data which illustrates good agreement between them is studied. Conductance of GNR as ...

Mohammad Taghi Ahmadi; Zaharah Johari; N. Aziziah Amin; Amir Hossein Fallahpour; Razali Ismail

2010-01-01T23:59:59.000Z

387

THERMAL NEUTRONIC REACTOR  

DOE Patents (OSTI)

A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

Spinrad, B.I.

1960-01-12T23:59:59.000Z

388

Thermally actuated thermionic switch  

DOE Patents (OSTI)

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

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

1982-09-30T23:59:59.000Z

389

Invited paper for the 30th International Thermal Conductivity ...  

Science Conference Proceedings (OSTI)

... of the FRM influences the radiative heat transfer between a ... dry cycling, humidity, impact resistance, industrial atmosphere, salt spray, temperature ...

2010-10-28T23:59:59.000Z

390

Improved Gas Storage Carbon with Enhanced Thermal Conductivity  

... (DOE target storage value) of methane at standard temperature and pressure is used in adsorbed natural gas applications, including vehicles. ...

391

Experimental Investigation on Anisotropic Effective Thermal Conductivity of Pebble Bed  

Science Conference Proceedings (OSTI)

Computational Tools, Modeling & Validation / Proceedings of the Nineteenth Topical Meeting on the Technology of Fusion Energy (TOFE) (Part 2)

Takehiko Yokomine

392

Thermal and Electrical Conductivities of Electroplated Gold (A25695)  

E-Print Network (OSTI)

Proc. Of The 17th Target Fabrication Specialists Meeting, San Diego, California, 2006; To Be Published In Fusion Science And Technology17th Target Fabrication Specialists Meeting San Diego California, US, 2006999613445

Bernat, T.P.

2006-12-08T23:59:59.000Z

393

Thermal conductivity and viscosity of self-assembled alcohol ...  

Science Conference Proceedings (OSTI)

... Aldrich) that have hydrophilic heads facing inward and hydropho- bic tails facing outward into the base fluid PAO (Chevron Phillips Chemical ...

2011-06-02T23:59:59.000Z

394

High Field Electrical Conduction and Its Relation to Thermal ...  

Science Conference Proceedings (OSTI)

Symposium, Advanced Materials for Power Electronics, Power Conditioning, and Power Conversion ... Potential Ceramic Dielectrics for Air Force Applications.

395

Thermal conductivity, microstructure and gas release from a 44 GWd ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Plutonium recycling in mixed oxide fuel (MOX) occurs in more ... burn-up and irradiation temperature profiles and Pu-content on properties and ...

396

Thermal and Electrical Conductivity Study of CNT-Carbon ...  

Science Conference Proceedings (OSTI)

Abstract Scope, A method is developed to incorporate carbon nanotubes in porous carbon microspheres. This is accomplished by dispersing Carbon Nanotubes ...

397

Experimental Technique to Conduct Thermal Shock Test on ...  

Science Conference Proceedings (OSTI)

Failure Analysis Case Studies from Refinery and Petrochemical Pilot Plants ... Failure of Electrical Submersible Pump of Oil Reservoir · Fan Blade Fracture in a  ...

398

Thermally Conductive Graphite Foam - Oak Ridge National Laboratory  

• Thermoelectric devices • Radiators • EMI shielding Patent ... Materials Science UT-Battelle, LLC Oak Ridge National Laboratory Office Phone: 865.576.9682

399

Quantum effects in thermal conduction: Nonequilibrium quantum discord and entanglement  

E-Print Network (OSTI)

We study the process of heat transfer through an entangled pair of two-level system, demonstrating the role of quantum correlations in this nonequilibrium process. While quantum correlations generally degrade with increasing the temperature bias, introducing spatial asymmetry leads to an intricate behavior: Connecting the qubits unequally to the reservoirs one finds that quantum correlations persist and increase with the temperature bias when the system is more weakly linked to the hot reservoir. In the reversed case, linking the system more strongly to the hot bath, the opposite, more natural behavior is observed, with quantum correlations being strongly suppressed upon increasing the temperature bias.

Lian-Ao Wu; Dvira Segal

2011-05-06T23:59:59.000Z

400

Density and Thermal Conductivity of Boron Nitride-alumina Mixed ...  

Science Conference Proceedings (OSTI)

Synthesis and Characterization of Plasma Polymerized Thin Films Deposited from Benzene and Hexamethyldisiloxane Using (PECVD) Method · Synthesis and ...

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


401

Quantum effects in thermal conduction: Nonequilibrium quantum discord and entanglement  

E-Print Network (OSTI)

We study the process of heat transfer through an entangled pair of two-level system, demonstrating the role of quantum correlations in this nonequilibrium process. While quantum correlations generally degrade with increasing the temperature bias, introducing spatial asymmetry leads to an intricate behavior: Connecting the qubits unequally to the reservoirs one finds that quantum correlations persist and increase with the temperature bias when the system is more weakly linked to the hot reservoir. In the reversed case, linking the system more strongly to the hot bath, the opposite, more natural behavior is observed, with quantum correlations being strongly suppressed upon increasing the temperature bias.

Wu, Lian-Ao

2011-01-01T23:59:59.000Z

402

Investigation on the Thermal Conductivity of Inorganic-Filler/Resin ...  

Science Conference Proceedings (OSTI)

Synthesis and Characterization of Pb Free Piezoelectric Ceramics - Barium ... Thermographic Characterization of Tensile Behavior in Railway Bogie Materials.

403

Thermal conductivity of nanoparticle suspensions Shawn A. Putnam,a  

E-Print Network (OSTI)

is the diffusion coefficient of water in ethanol, 2a 50 m is the line-heater separation, and 1/ f is the time required for water to diffuse half the distance between the metal heaters. This corresponds to low for thermodiffusion in our analysis of for water/ ethanol mixtures using dn/dT, cdn/dc, Dc, and thermodiffu- sion

Braun, Paul

404

Determining Thermal Conductivity of Simulated Feed for High Level ...  

Science Conference Proceedings (OSTI)

... of Fluidized Bed Steam Reforming (FBSR) with Hanford Low Activity Wastes ... Level Waste at the Defense Waste Processing Facility through Sludge Batch 7b.

405

Thermally Conductive Graphite Foam - Oak Ridge National Laboratory  

Product Name Manufacturer Relevance CFOAM Touchstone Research Lab Aerospace tooling ... Hypersonic vehicles Aerobraking structures for planetary exploration

406

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

Open Energy Info (EERE)

more complicated two-layer problem that can be computed using inexpensive personal computers and spreadsheet software. The most demanding mathematical requirement is the ability...

407

Differential Thermal Analysis of Nickel-Base Superalloys  

Science Conference Proceedings (OSTI)

Differential thermal analysis was performed on over 200 nickel-base superalloys that ... differential thermal analysis (DTA) to simply and accurately measure.

408

NSLS Conduct of Operations  

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

Securing the X-Ray Tunnel (LS-OPS-0003) Qualified Search Personnel for NSLS Accelerators (LS-ESH-0009) General Procedures Caution Tags (LS-OPS-0004) Conduct of...

409

Thermal via placement in 3D ICs  

E-Print Network (OSTI)

As thermal problems become more evident, new physical design paradigms and tools are needed to alleviate them. Incorporating thermal vias into integrated circuits (ICs) is a promising way of mitigating thermal issues by lowering the thermal resistance of the chip itself. However, thermal vias take up valuable routing space, and therefore, algorithms are needed to minimize their usage while placing them in areas where they would make the greatest impact. With the developing technology of three-dimensional integrated circuits (3D ICs), thermal problems are expected to be more prominent, and thermal vias can have a larger impact on them than in traditional 2D ICs. In this paper, thermal vias are assigned to specific areas of a 3D IC and used to adjust their effective thermal conductivities. The thermal via placement method makes iterative adjustments to these thermal conductivities in order to achieve a desired maximum temperature objective. Finite element analysis (FEA) is used in formulating the method and in calculating temperatures quickly during each iteration. As a result, the method efficiently achieves its thermal objective while minimizing the thermal via utilization.

Brent Goplen

2005-01-01T23:59:59.000Z

410

Micro-machined thermo-conductivity detector  

DOE Patents (OSTI)

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

Yu, Conrad (Antioch, CA)

2003-01-01T23:59:59.000Z

411

QUASI-STEADY CONFIGURATIONS OF CONDUCTIVE INTRACLUSTER MEDIA  

SciTech Connect

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

Voit, G. M., E-mail: voit@pa.msu.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2011-10-10T23:59:59.000Z

412

Thermal to electricity conversion using thermal magnetic properties  

DOE Patents (OSTI)

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

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

2010-04-27T23:59:59.000Z

413

Effects of airflow infiltration on the thermal performance of internally  

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

Effects of airflow infiltration on the thermal performance of internally Effects of airflow infiltration on the thermal performance of internally insulated ducts Title Effects of airflow infiltration on the thermal performance of internally insulated ducts Publication Type Journal Article Year of Publication 2000 Authors Levinson, Ronnen M., William W. Delp, Darryl J. Dickerhoff, and Mark P. Modera Journal Energy and Buildings Volume 32 Pagination 345-354 Keywords building design, Heat Island Abstract Air flowing through a supply duct infiltrates perviously faced, porous, internal duct insulation, degrading its thermal performance. Encapsulating the insulation's air-facing surface with an impervious barrier prevents infiltration, increasing the capacity of the conditioned supply air to heat or cool the space to which it is delivered. This study determined the air-speed dependence of the thermal conductivity of fiberglass insulation by measuring the inlet-to-outlet temperature drop of heated air flowing through a long, insulated flexible duct. The conductivity of a flexible duct's low-density, internal, fiberglass-blanket insulation increased with the square of the duct air speed, rising by 140% as the duct air speed increased from 0 to 15 m s-1. At air speeds recommended for branch ducts, the conductivity of such insulation would increase by 6% above its still-air value in a residential system and by 16% in a commercial system. Results partially agreed with those reported by an earlier study. Simulations indicate that encapsulating the air-stream surface of internal fiberglass duct insulation with an impervious barrier increases the effectiveness with which a duct delivers the thermal capacity of supply air by 0.15%-0.9% in typical duct systems.

414

CONDUCTING A RECORDS INVENTORY  

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

PROCEDURE FOR CONDUCTING A RECORDS INVENTORY PROCEDURE FOR CONDUCTING A RECORDS INVENTORY Revision 1 10/31/07 Approved by: DOE Records Management Division, IM-23 PROCEDURE FOR CONDUCTING A RECORDS INVENTORY 1. GENERAL. A records inventory is compiling a descriptive list of each record series or system, including the location of the records and any other pertinent data. A records inventory is not a list of each document or each folder. 2. DEFINE THE RECORDS INVENTORY GOAL(S). The goals of a records inventory should be to: a. Gather information for scheduling purposes; b. Prepare for conversion to other media or to identify the volume of classified and/or permanent records in your organization's custody; and c. Identify any existing shortcomings, deficiencies, or problems with

415

REACTOR GROUT THERMAL PROPERTIES  

DOE Green Energy (OSTI)

Savannah River Site has five dormant nuclear production reactors. Long term disposition will require filling some reactor buildings with grout up to ground level. Portland cement based grout will be used to fill the buildings with the exception of some reactor tanks. Some reactor tanks contain significant quantities of aluminum which could react with Portland cement based grout to form hydrogen. Hydrogen production is a safety concern and gas generation could also compromise the structural integrity of the grout pour. Therefore, it was necessary to develop a non-Portland cement grout to fill reactors that contain significant quantities of aluminum. Grouts generate heat when they set, so the potential exists for large temperature increases in a large pour, which could compromise the integrity of the pour. The primary purpose of the testing reported here was to measure heat of hydration, specific heat, thermal conductivity and density of various reactor grouts under consideration so that these properties could be used to model transient heat transfer for different pouring strategies. A secondary purpose was to make qualitative judgments of grout pourability and hardened strength. Some reactor grout formulations were unacceptable because they generated too much heat, or started setting too fast, or required too long to harden or were too weak. The formulation called 102H had the best combination of characteristics. It is a Calcium Alumino-Sulfate grout that contains Ciment Fondu (calcium aluminate cement), Plaster of Paris (calcium sulfate hemihydrate), sand, Class F fly ash, boric acid and small quantities of additives. This composition afforded about ten hours of working time. Heat release began at 12 hours and was complete by 24 hours. The adiabatic temperature rise was 54 C which was within specification. The final product was hard and displayed no visible segregation. The density and maximum particle size were within specification.

Steimke, J.; Qureshi, Z.; Restivo, M.; Guerrero, H.

2011-01-28T23:59:59.000Z

416

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

Open Energy Info (EERE)

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

417

Lithium ion conducting electrolytes  

DOE Patents (OSTI)

The present invention relates generally to highly conductive alkali-metal ion non-crystalline electrolyte systems, and more particularly to novel and unique molten (liquid), rubbery, and solid electrolyte systems which are especially well suited for use with high current density electrolytic cells such as primary and secondary batteries.

Angell, Charles Austen (Mesa, AZ); Liu, Changle (Midland, MI); Xu, Kang (Montgomery Village, MD); Skotheim, Terje A. (Tucson, AZ)

1999-01-01T23:59:59.000Z

418

Lithium ion conducting electrolytes  

DOE Patents (OSTI)

A liquid, predominantly lithium-conducting, ionic electrolyte having exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature, and comprising the lithium salts selected from the group consisting of the thiocyanate, iodide, bromide, chloride, perchlorate, acetate, tetrafluoroborate, perfluoromethane sulfonate, perfluoromethane sulfonamide, tetrahaloaluminate, and heptahaloaluminate salts of lithium, with or without a magnesium-salt selected from the group consisting of the perchlorate and acetate salts of magnesium. Certain of the latter embodiments may also contain molecular additives from the group of acetonitrile (CH.sub.3 CN) succinnonitrile (CH.sub.2 CN).sub.2, and tetraglyme (CH.sub.3 --O--CH.sub.2 --CH.sub.2 --O--).sub.2 (or like solvents) solvated to a Mg.sup.+2 cation to lower the freezing point of the electrolyte below room temperature. Other particularly useful embodiments contain up to about 40, but preferably not more than about 25, mol percent of a long chain polyether polymer dissolved in the lithium salts to provide an elastic or rubbery solid electrolyte of high ambient temperature conductivity and exceptional 100.degree. C. conductivity. Another embodiment contains up to about but not more than 10 mol percent of a molecular solvent such as acetone.

Angell, C. Austen (Tempe, AZ); Liu, Changle (Tempe, AZ)

1996-01-01T23:59:59.000Z

419

A Simple System for Mapping Conductivity Microstructure  

Science Conference Proceedings (OSTI)

A system for spatial mapping of the temperature variance dissipation rate ? based on conductivity micro-structure measurements from a towyo platform is described. The spatial response of the microconductivity probe is approximately that of a one-...

Libe Washburn; Thomas K. Deaton

1986-09-01T23:59:59.000Z

420

Comparison of Towed Conductivity Sensor Performance  

Science Conference Proceedings (OSTI)

Electrical conductivity sensors are often used to obtain measurements of small-scale fluctuations, or microstructure, in the ocean. In applications on towed instrument packages, they provide the only way to estimate temperature fluctuations on ...

J. P. Dugan; B. W. Stalcup

1988-02-01T23:59:59.000Z

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.


421

AC Loss Measurements with a Cryocooled Sample  

SciTech Connect

A new cryostat cooled by a closed-cycle Cryomech GB-37 cryocooler for superconductor measurements at temperatures down to 20 K is described. The sample is conductively coupled to the cold stage so as to minimize vibration and thermal stresses. AC losses have been measured calorimetrically in several HTSC coils that have been wound to simulate sub-scale transformer winding pairs. Stable temperatures down to 20 K were reached on these coils, allowing measurements at practical levels of ac current and I{sub c}. By using short ac current pulses, losses on individual turns could be resolved. Results are reported mainly to showcase the apparatus, measurement procedure and analytical approach.

Schwenterly, S.W.

2001-02-15T23:59:59.000Z

422

Low Temperature Proton Conductivity  

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

and and MEAs at Freezing Temperatures Thomas A. Zawodzinski, Jr. Case Western Reserve University Cleveland, Ohio 2 Freezing Fuel Cells: Impact on MEAS Below 0 o C *Transport processes/motions slow down: questions re: lower conductivity,water mobility etc *Residual water will have various physical effects in different portions of the MEA questions re: durability of components 3 3 'States' of Water in Proton Conductors ? Freezing (bulk), bound freezable, bound non freezable water states claimed based on DSC * Freezing water more mobile, allegedly important for high conductivity Analysis common for porous systems Does the presence of these states matter? Why? 4 'State of Water' in PEMs At T < 0 o C *'Liquid-like' water freezes *'Non-freezing' fraction: water of solvation at pore

423

Oxygen ion conducting materials  

DOE Patents (OSTI)

An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

Vaughey, John (Elmhurst, IL); Krumpelt, Michael (Naperville, IL); Wang, Xiaoping (Downers Grove, IL); Carter, J. David (Bolingbrook, IL)

2003-01-01T23:59:59.000Z

424

Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders  

SciTech Connect

Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate’s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.

Johnson, Matthew (DOE/NNSA Kansas City Plant (United States)); Weyant, J.; Garner, S. (Advanced Cooling Technologies, Inc. (Lancaster, PA (United States)); Occhionero, M. (CPS Technologies Corporation, Norton, MA (United States))

2010-01-07T23:59:59.000Z

425

Midtemperature solar systems test facility predictions for thermal performance based on test data: Sun-Heet nontracking solar collector  

DOE Green Energy (OSTI)

Sandia National Laboratories, Albuquerque (SNLA), is currently conducting a program to predict the performance and measure the characteristics of commercially available solar collectors that have the potential for use in industrial process heat and enhanced oil recovery applications. The thermal performance predictions for the Sun-Heet nontracking, line-focusing parabolic trough collector at five cities in the US are presented. (WHK)

Harrison, T.D.

1981-03-01T23:59:59.000Z

426

Plasma momentum meter for momentum flux measurements  

DOE Patents (OSTI)

Invention comprises an instrument in which momentum flux onto a biasable target plate is transferred via a suspended quartz tube onto a sensitive force transducer--a capacitance-type pressure gauge. The transducer is protected from thermal damage, arcing and sputtering, and materials used in the target and pendulum are electrically insulating, rigid even at elevated temperatures, and have low thermal conductivity. The instrument enables measurement of small forces (10.sup.-5 to 10.sup.3 N) accompanied by high heat fluxes which are transmitted by energetic particles with 10's of eV of kinetic energy in a intense magnetic field and pulsed plasma environment.

Zonca, Fulvio (Rome, IT); Cohen, Samuel A. (Hopewell, NJ); Bennett, Timothy (Princeton, NJ); Timberlake, John R. (Allentown, NJ)

1993-01-01T23:59:59.000Z

427

Plasma momentum meter for momentum flux measurements  

DOE Patents (OSTI)

Invention comprises an instrument in which momentum flux onto a biasable target plate is transferred via a suspended quartz tube onto a sensitive force transducer - a capacitance-type pressure gauge. The transducer is protected from thermal damage, arcing and sputtering, and materials used in the target and pendulum are electrically insulating, rigid even at elevated temperatures, and have low thermal conductivity. The instrument enables measurement of small forces (10{sup {minus}5} to 10{sup 3} N) accompanied by high heat fluxes which are transmitted by energetic particles with 10`s of eV of kinetic energy in an intense magnetic field and pulsed plasma environment.

Zonca, F.; Cohen, S.A.; Bennett, T.; Timberlake, J.R.

1991-12-31T23:59:59.000Z

428

Plasma momentum meter for momentum flux measurements  

DOE Patents (OSTI)

Invention comprises an instrument in which momentum flux onto a biasable target plate is transferred via a suspended quartz tube onto a sensitive force transducer - a capacitance-type pressure gauge. The transducer is protected from thermal damage, arcing and sputtering, and materials used in the target and pendulum are electrically insulating, rigid even at elevated temperatures, and have low thermal conductivity. The instrument enables measurement of small forces (10[sup [minus]5] to 10[sup 3] N) accompanied by high heat fluxes which are transmitted by energetic particles with 10's of eV of kinetic energy in an intense magnetic field and pulsed plasma environment.

Zonca, F.; Cohen, S.A.; Bennett, T.; Timberlake, J.R.

1991-01-01T23:59:59.000Z

429

A STUDY OF ATES THERMAL BEHAVIOR USING A STEADY FLOW MODEL  

E-Print Network (OSTI)

thermal conductivity, Aau heat capacity per unit volume, Ca,thermal conductivity Ac and heat capacity per unit volumeCc• Cw• The heat capacity per unit volume of water is All

Doughty, Christine

2013-01-01T23:59:59.000Z

430

EFFECT OF HEAT TREATMENT ON THERMAL PROPERTIES OF PITCH-BASED AND PAN-BASED CARBON-CARBON COMPOSITES  

Science Conference Proceedings (OSTI)

Thermal properties of two directional (2D) pitch-based carbon fiber with charred resin and three directional (3D) PAN-based carbon fiber with CVI carbon matrix C/C composite were investigated for non-heat treated (NHT) and heat treated (HT) materials through the thickness (z-direction). Heat treatment was performed at 1800, 2100 and 2400 oC for 1-hr in inert argon atmosphere. Thermal diffusivity, heat capacity and bulk density were measured to calculate thermal conductivity. Thermal diffusivity and conductivity was the highest for 3D C/C heat treated at maximum temperature with non-heat treated one exhibiting the lowest one. Similarly, 2D C/C heat treated at maximum temperature exhibited the highest thermal diffusivity and thermal conductivity. Polarized light microscopy (PLM) images of HTT C/C show a progressive improvement in microstructure when compared to NHT C/C. However, HTT 2D and 3D C/C composites exhibited extensive shrinkage of charred resin and CVI carbon matrix, respectively, from fibers resulting in intra and inter-bundles cracking when compared to NHT one. Raman spectroscopy and XRD results of NHT and HTT C/C indicated increased ordering of structure. A progressive improvement in thermal properties was observed with increased heat treatment temperatures.

Iqbal, Sardar S. [Southern Illinois University; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL; Fillip, Peter [Southern Illinois University

2011-01-01T23:59:59.000Z

431

Thermal spallation drilling  

DOE Green Energy (OSTI)

Thermal spallation drilling is an underdeveloped process with great potential for reducing the costs of drilling holes and mining shafts and tunnels in most very hard rocks. Industry has used this process to drill blast holes for emplacing explosives and to quarry granite. Some theoretical work has been performed, and many signs point to a great future for this process. The Los Alamos National Laboratory has studied the theory of the spallation process and is conducting experiments to prove out the system and to adapt it for use with a conventional rotary rig. This report describes work that has been accomplished at the Laboratory on the development of thermal spallation drilling and some work that is projected for the future on the system. 3 references, 3 figures.

Williams, R.E.

1985-01-01T23:59:59.000Z

432

Thermal transient anemometer  

DOE Patents (OSTI)

A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

Bailey, J.L.; Vresk, J.

1989-07-18T23:59:59.000Z

433

Definition: Hydraulic Conductivity | Open Energy Information  

Open Energy Info (EERE)

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

434

LABORATORY VI ENERGY AND THERMAL PROCESSES  

E-Print Network (OSTI)

LABORATORY VI ENERGY AND THERMAL PROCESSES Lab VI - 1 The change of the internal energy of a system temperature by sweating to cool down. Running seems to be the conversion of chemical energy to thermal energy energy into thermal energy, you decide to make some measurements in the laboratory. To make

Minnesota, University of

435

Normal Conducting CLIC Technology  

Science Conference Proceedings (OSTI)

The CLIC (Compact Linear Collider) multi?lateral study group based at CERN is studying the technology for an electron?positron linear collider with a centre?of?mass energy up to 5 TeV. In contrast to the International Linear Collider (ILC) study which has chosen to use super?conducting cavities with accelerating gradients in the range of 30–40 MV/m to obtain centre?of?mass collision energies of 0.5–1 TeV

Erk Jensen; CLIC Study Team

2006-01-01T23:59:59.000Z

436

Experimental Investigation on Thermal Properties of a Steel-jacketed Steam Heating Pipeline with Vacuum Insulation  

E-Print Network (OSTI)

The steel-jacketed steam heating pipeline employs vacuum insulation to improve the insulating effect and reduce the corrosion, and hence increases the heat transfer efficiency of the heating network and building energy efficiency. It is important in improving the thermal insulation to investigate the impact of factors that insulate the effects and thermal properties of the pipeline. The thermal insulation of this pipeline comprises the vacuum layer and the insulating material layer. Experiments were performed to measure the combined heat transfer and equivalent thermal conductivities of the insulating material in the vacuum and rarefied air employed in the pipeline's insulation. The thermal properties of this type of insulation at vacuum pressures of 0.5~1013mbar, employing thermal media temperatures of 343~573K and with different thicknesses of vacuum layer, are discussed for this pipeline, for which diameters of inner steel pipe/steel jacket are DN50/DN250, DN100/DN300, DN200/DN500 and DN500/DN850, respectively. The results show that reduction in vacuum pressure reduces the heat loss in the pipeline. The equivalent thermal conductivity of the insulating material layer is distinctively lower than the vacuum layer, but decreasing the vacuum pressure improves the insulating effect of vacuum layer substantially more than insulating the material layer. As the vacuum pressure decreases from 1013mbar (atmospheric pressure) to 10mbar at the thermal media temperature of 523K e.g., the reduction of equivalent thermal conductivities of vacuum layer is approximately three times greater than that of insulating material layer. The equivalent thermal conductivities of the vacuum layer are lower and decease faster as the vacuum pressure is lower than 100mbar, but the equivalent thermal conductivities of insulating material layer are lower and decease faster as the vacuum pressure is lower than 50mbar. The pressure in vacuum insulation should be controlled lower than 20mbar to achieve desirable insulating effects. Every 10mm addition of thickness of insulating material layer (every 10mm reduction of thickness of vacuum layer) decreases the heat loss of approximately 6.8 percent at the vacuum pressure of 0.5mbar.

Na, W.; Zou, P.

2006-01-01T23:59:59.000Z

437

PCM energy storage during defective thermal cycling.  

E-Print Network (OSTI)

??Incomplete thermal cycling affects storage capacities of phase change materials (PCMs). Existing PCM measuring methods are presented with their drawbacks. A new device named “the… (more)

Koekenbier, S.F.

2011-01-01T23:59:59.000Z

438

Thermal transport of the single-crystal rare-earth nickel borocarbides RNi2B2C  

E-Print Network (OSTI)

The quaternary intermetallic rare-earth nickel borocarbides RNi2B2C are a family of compounds that show magnetic behavior, superconducting behavior, and/or both. Thermal transport measurements reveal both electron and phonon scattering mechanisms, and can provide information on the interplay of these two long-range phenomena. In general the thermal conductivity kappa is dominated by electrons, and the high temperature thermal conductivity is approximately linear in temperature and anomalous. For R=Tm, Ho, and Dy the low-temperature thermal conductivity exhibits a marked loss of scattering at the antiferromagnetic ordering temperature T-N. Magnon heat conduction is suggested for R=Tm. The kappa data for R=Ho lends evidence for gapless superconductivity in this material above T-N. Unlike the case for the non-magnetic superconductors in the family, R=Y and Lu, a phonon peak in the thermal conductivity below T-c is not observed down to T=1.4 K for the magnetic superconductors. Single-crystal quality seems to have a strong effect on kappa. The electron-phonon interaction appears to weaken as one progresses from R=Lu to R=Gd. The resistivity data shows the loss of scattering at T-N for R=Dy, Tb, and Gd; and the thermoelectric power for all three of these materials exhibits an enhancement below T-N.

Hennings, BD; Naugle, Donald G.; Canfield, PC.

2002-01-01T23:59:59.000Z

439

Thermal Management of Onboard Cryogenic Hydrogen Storage Systems...  

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

Plan: (A) System Weight and Volume (C) Efficiency (E) ChargingDischarging Rates (J) Thermal Management Technical Targets In this project, studies are being conducted to develop...

440

Alloy Development for Copper Diamond Composites for Thermal ...  

Science Conference Proceedings (OSTI)

One approach to meeting the challenges is to add diamond particles to a copper matrix to improve thermal conductivity and lower CTE simultaneously.

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

composites for high performance electronic packaging and thermal ...  

Science Conference Proceedings (OSTI)

The applications include; leading edges and engine components for the National Aerospace Plane, radiators for space power, flexible high conductance thermal ...

442

Unglazed transpired solar collector having a low thermal ...  

An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprising an unglazed absorber formed of low thermal-conductance ...

443

Ceramic thermal barrier coating for rapid thermal cycling applications  

DOE Patents (OSTI)

A thermal barrier coating for metal articles subjected to rapid thermal cycling includes a metallic bond coat deposited on the metal article, at least one MCrAlY/ceramic layer deposited on the bond coat, and a ceramic top layer deposited on the MCrAlY/ceramic layer. The M in the MCrAlY material is Fe, Ni, Co, or a mixture of Ni and Co. The ceramic in the MCrAlY/ceramic layer is mullite or Al.sub.2 O.sub.3. The ceramic top layer includes a ceramic with a coefficient of thermal expansion less than about 5.4.times.10.sup.-6 .degree.C.sup.-1 and a thermal conductivity between about 1 J sec.sup.-1 m.sup.-1 .degree.C.sup.-1 and about 1.7 J sec.sup.-1 m.sup.-1 .degree.C.sup.-1.

Scharman, Alan J. (Hebron, CT); Yonushonis, Thomas M. (Columbus, IN)

1994-01-01T23:59:59.000Z

444

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network (OSTI)

using aquifers for thermal energy storage. Problems outlinedmatical Modeling of Thermal Energy Storage in Aquifers,"Proceed- ings of Aquifer Thermal Energy Storage Workshop,

Tsang, C.-F.

2011-01-01T23:59:59.000Z

445

AQUIFER THERMAL ENERGY STORAGE  

E-Print Network (OSTI)

aquifers for thermal energy storage. Problems outlined aboveModeling of Thermal Energy Storage in Aquifers," Proceed-ings of Aquifer Thermal Energy Storage Workshop, Lawrence

Tsang, C.-F.

2011-01-01T23:59:59.000Z

446

Soil properties influencing apparent electrical conductivity: a review  

Science Conference Proceedings (OSTI)

The most common method for in situ assessment of soil salinity, namely the electrical conductivity (EC) of the soil solution (EC"w), is to measure the apparent electrical conductivity (EC"a) and volumetric water content (@q) of the soil and apply measured ... Keywords: Apparent (effective) electrical conductivity, Soil salinity

Shmulik P. Friedman

2005-03-01T23:59:59.000Z

447

In-plane ESR microwave conductivity measurements and electronic band structure studies of the organic superconductor, {beta}'-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}.  

SciTech Connect

The electronic structure of the organic superconductor {beta}''-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} (BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) was characterized with the use of electron spin resonance (ESR) spectroscopy and electronic band structure calculations. The room-temperature ESR line width is 24-27 G in the plane of a donor molecule layer (i.e., in the ab-plane) and {approx}32 G along the normal to this plane (i.e., along the c*-direction). The ab-plane anisotropy of the microwave conductivity was extracted for the first time from the ESR Dysonian line shape analysis. The in-plane conductivity varies sinusoidally, is maximal along the interstack direction (b-axis), and is minimal along the donor stack direction (a-axis). The Fermi surfaces of the title compound consist of a 2D hole pocket and a pair of 1D wavy lines. The directions for the in-plane conductivity maximum and minimum are in excellent agreement with the electronic band structure calculated for {beta}''-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}, and the origin of the in-plane conductivity anisotropy lies in the one-dimensional part of the Fermi surface. This is the first time that an organic conductor shows Dysonian ESR line shape due to its 2D and strongly metallic nature, yet the 1D character is revealed simultaneously through the in-plane conductivity anisotropy.

Wang, H. H.; VanZile, M. L.; Schlueter, J. A.; Geiser, U.; Kini, A. M.; Sche, P. P.; Koo, H.-J.; Whangbo, M.-H.; Nixon, P. G.; Winter, R. W.; Gard, G. L.; Chemistry; North Carolina State Univ.; Portland State Univ.

1999-07-01T23:59:59.000Z

448

HYDRAULIC CONDUCTIVITY OF ESSENTIALLY SATURATED PEAT  

SciTech Connect

The Savannah River National Laboratory measured the hydraulic conductivity of peat samples using method ASTM D4511-00. Four samples of peat were packed into 73mm diameter plastic tubes and saturated from the bottom up with water. The columns were packed with Premier ProMoss III TBK peat to a dry density of approximately 0.16 gm/cc (10 lb/ft3). One column was packed using oven dried peat and the other 3 were packed using as delivered peat. The oven dried sample was the most difficult to saturate. All of the peat samples expanded during saturation resulting in a sample length (L) that was longer than when the sample was initially packed. Table 1 contains information related to the column packing. After saturation the hydraulic conductivity test was conducted using the apparatus shown in Figure 1. Three of the samples were tested at 2 different flow conductions, 1 high and 1 low. Table 2 and Figure 2 contain the results of the hydraulic conductivity testing. Each test was run for a minimum of 40 minutes to allow the test conditions to stabilize. The hydraulic conductivity at the end of each test is reported as the hydraulic conductivity for that test. The hydraulic conductivity of the 4 peat samples is 0.0052 {+-} 0.0009 cm/sec. This result compares well with the hydraulic conductivity measured in the pilot scale peat bed after approximately 2 months of operation. The similarity in results between the dry pack sample and moist pack samples shows the moisture content at the time of packing had a minimal effect on the hydraulic conductivity. Additionally, similarity between the results shows the test is reproducible. The hydraulic conductivity results are similar to those reported by other tests of peat samples reported in the literature.

Nichols, R

2008-02-27T23:59:59.000Z

449

Phonon Heat Conduction In A Semiconductor Nanowire  

E-Print Network (OSTI)

ic phonon dispersion due to spatial confinement, and (ii) change in the nonequilibrium phonon distribution due to partially diffuse boundary scattering. Numerical simulation is performed for a silicon nanowire with boundaries characterized by different interface roughness. Phonon confinement and boundary scattering lead to a significant decrease of the lattice thermal conductivity. The value of this decrease and its interface roughness and temperature dependence are different from the predictions of the early models. The observed change in thermal resistance has to be taken into account in simulation of deepsubmicron and nanometer-scale devices. 2001 American Institute of Physics. PACS: 68.65.La, 66.70.+f, 63.22.+m, 68.35. References

Joe Zou; Alexander Balandin; Jie Zou; Er Bal

2000-01-01T23:59:59.000Z

450

Final Design and Experimental Validation of the Thermal Performance of the LHC Lattice Cryostats  

E-Print Network (OSTI)

The recent commissioning and operation of the LHC String 2 have given a first experimental validation of the global thermal performance of the LHC lattice cryostat at nominal cryogenic conditions. The cryostat designed to minimize the heat inleak from ambient temperature, houses under vacuum and thermally protects the cold mass, which contains the LHC twin-aperture superconducting magnets operating at 1.9 K in superfluid helium. Mechanical components linking the cold mass to the vacuum vessel, such as support posts and insulation vacuum barriers are designed with efficient thermalisations for heat interception to minimise heat conduction. Heat inleak by radiation is reduced by employing multilayer insulation (MLI) wrapped around the cold mass and around an aluminium thermal shield cooled to about 60 K. Measurements of the total helium vaporization rate in String 2 gives, after substraction of supplementary heat loads and end effects, an estimate of the total thermal load to a standard LHC cell (107 m) includi...

Bourcey, N; Parma, V; Poncet, A; Rohmig, P; Serio, L; Skoczen, Blazej; Tock, J P; Williams, L R

2004-01-01T23:59:59.000Z

451

Mobile home weatherization measures: A study of their effectiveness  

SciTech Connect

The Solar Energy Research Institute (SERI) was funded by the Department of Energy's Office of Buildings and Community Systems (DOE OBCS) in FY 1987 and 1988 to investigate cost effective ways to weatherize mobile homes constructed prior to the enactment of HUD Thermal Standards in 1976. In FY 1987 SERI studied the effectiveness of a variety of infiltration-reducing retrofits by monitoring 20 units in the field before, during, and after applications of air tightening measures. In FY 1988 we began studying measures intended to reduce envelope conduction losses. These measures included storm windows, insulated skirting, and wall, roof, and floor insulation. This part of the project resulted in the development of a short-term testing method for measuring the thermal impact of individual conduction-reducing retrofits.

Judkoff, R.; Hancock, E.; Franconi, E.; Hanger, R.; Weiger, J.

1988-12-01T23:59:59.000Z

452

Energy dependence of the /sup 238/U thermal capture cross section. [25 to 450/sup 0/C  

Science Conference Proceedings (OSTI)

Integral activation measurements supported the thermal neutron energy dependence of /sup 238/U assumed in the ENDF/B-IV evaluation. The activation measurements were conducted in a thermally insulated graphite block at the side of the SP Reactor. The block was thermally heated to temperatures up to 450/sup 0/C. In addition to heating, gasolinium filters were used to tailor the neutron spectra incident on the foils. The metallic foils consisted of copper and depleted uranium. Copper served as the 1/v reference. Activation ratios of /sup 238/U to /sup 63/Cu in the tailored spectrum were compared with corresponding ratios in a well thermalized flux at room temperature. The difference in this ratio is strongly dependent on the energy dependence of the /sup 238/U cross section. 8 figures, 1 table.

Baumann, N.P.; Owais, M.

1980-01-01T23:59:59.000Z

453

THERMALLY DRIVEN ATMOSPHERIC ESCAPE  

Science Conference Proceedings (OSTI)

Accurately determining the escape rate from a planet's atmosphere is critical for determining its evolution. A large amount of Cassini data is now available for Titan's upper atmosphere and a wealth of data is expected within the next decade on escape from Pluto, Mars, and extra-solar planets. Escape can be driven by upward thermal conduction of energy deposited well below the exobase, as well as by nonthermal processes produced by energy deposited in the exobase region. Recent applications of a model for escape driven by upward thermal conduction, called the slow hydrodynamic escape model, have resulted in surprisingly large loss rates for the atmosphere of Titan, Saturn's largest moon. Based on a molecular kinetic simulation of the exobase region, these rates appear to be orders of magnitude too large. Therefore, the slow hydrodynamic model is evaluated here. It is shown that such a model cannot give a reliable description of the atmospheric temperature profile unless it is coupled to a molecular kinetic description of the exobase region. Therefore, the present escape rates for Titan and Pluto must be re-evaluated using the atmospheric model described here.

Johnson, Robert E., E-mail: rej@virginia.ed [Engineering Physics, Thornton Hall B102, University of Virginia, Charlottesville, VA 22902 (United States); Physics Department, New York University, New York, NY 10003 (United States)

2010-06-20T23:59:59.000Z

454

Nuclear Instruments and Methods in Physics Research A 432 (1999) 403}409 Measurement of the thermal and fast neutron #ux in a research  

E-Print Network (OSTI)

. Introduction A new type of "bre detector was developed at Nagoya University recently [1}3] and tested of these two materials are rather similar, the quartz "bre is superior regarding the radiation level in which, development of such a detector is of clear importance, and the measurements reported in this paper contribute

Pázsit, Imre

455

High temperature thermographic measurements of laser heated silica  

SciTech Connect

In situ spatial and temporal surface temperature profiles of CO{sub 2} laser-heated silica were obtained using a long wave infrared (LWIR) HgCdTe camera. Solutions to the linear diffusion equation with volumetric and surface heating are shown to describe the temperature evolution for a range of beam powers, over which the peak surface temperature scales linearly with power. These solutions were used with on-axis steady state and transient experimental temperatures to extract thermal diffusivity and conductivity for a variety of materials, including silica, spinel, sapphire, and lithium fluoride. Experimentally-derived thermal properties agreed well with reported values and, for silica, thermal conductivity and diffusivity are shown to be approximately independent of temperature between 300 and 2800K. While for silica our analysis based on a temperature independent thermal conductivity is shown to be accurate, for other materials studied this treatment yields effective thermal properties that represent reasonable approximations for laser heating. Implementation of a single-wavelength radiation measurement in the semi-transparent regime is generally discussed, and estimates of the apparent temperature deviation from the actual outer surface temperature are also presented. The experimental approach and the simple analysis presented yield surface temperature measurements that can be used to validate more complex physical models, help discriminate dominant heat transport mechanisms, and to predict temperature distribution and evolution during laser-based material processing.

Elhadj, S; Yang, S T; Matthews, M J; Cooke, D J; Bude, J D; Johnson, M; Feit, M; Draggoo, V; Bisson, S E

2009-11-02T23:59:59.000Z

456

The effect of process parameters on the thermal conditions during moving mold ESR  

Science Conference Proceedings (OSTI)

Several experimental melts were conducted using a moving mold electroslag remelting furnace. The conditions of electrode immersion depth, slag cap thickness, and melt current were varied. Mold wall temperatures and slag pool temperatures were measured and the heat flux through the mold wall was calculated. The relationships between varying ESR melt parameters and the resultant thermal conditions were examined. The thermal profile of the mold, the heat transfer to the mold coolant total and fractional, and the formation of a slag skin were studied.

Heilman, J.E. [Carpenter Technology Corp., Reading, PA (United States); Damkroger, B.K. [Sandia National Labs., Albuquerque, NM (United States)

1994-09-01T23:59:59.000Z

457

Conducting and Optical Properties of Transparent Conducting Indium-Doped Zinc Oxide Thin Films by Sol-Gel Processing  

Science Conference Proceedings (OSTI)

Transparent conducting oxides were successfully prepared from mixed zinc nitrate hexahydrate and indium nitrate hydrate solutions in ethylene glycol using sol-gel technique. The In content in the film was varied (0, 2, 10, 20, 40, 75 and 100 atom %). Films were prepared by spin coating of the liquid precursors followed by thermal decomposition at 400° C after each layer. According to X-ray diffraction (XRD) measurements, the pure ZnO and pure InO films (0 and at 100 % In) were crystalline as-deposited. The crystallinity was suppressed in mixed compositions such that the films with compositions between 10 and 75 at % were amorphous. All the films were transparent with the transmission cut-off frequency near 400 nm, which is characteristic of TCO materials. All as-deposited films were conductive with 0 and 100 atom % In having the lowest resistivities. The resistivity of all compositions were improved by post-deposition reducing anneal in pure Ar at 300° C. The lowest resistivity of 0.2 ?cm was obtained for the pure ZnO after Ar anneal. It was two-orders of magnitude higher than reported in the literature for the In-doped ZnO, which was attributed to the low processing temperature. The resistivities of as-deposited and annealed in Ar films were increased by consequent air anneal at 300° C.

Huang, S.; Kaydanova, T.; Miedaner, A.; Ginley, D.S.

2004-01-01T23:59:59.000Z

458

Equilibrium Models of Galaxy Clusters with Cooling, Heating and Conduction  

E-Print Network (OSTI)

It is generally argued that most clusters of galaxies host cooling flows in which radiative cooling in the centre causes a slow inflow. However, recent observations by Chandra and XMM conflict with the predicted cooling flow rates. Amongst other mechanisms, heating by a central active galactic nucleus and thermal conduction have been invoked in order to account for the small mass deposition rates. Here, we present a family of hydrostatic models for the intra-cluster medium where radiative losses are exactly balanced by thermal conduction and heating by a central source. We describe the features of this simple model and fit its parameters to the density and temperature profiles of Hydra A.

M. Bruggen

2003-03-20T23:59:59.000Z

459

Wafer heating mechanisms in a molecular gas, inductively coupled plasma: in situ, real time wafer surface measurements and three-dimensional thermal modeling  

Science Conference Proceedings (OSTI)

The authors report measurements and modeling of wafer heating mechanisms in an Ar/O{sub 2} inductively coupled plasma (ICP). The authors employed a commercially available on-wafer sensor system (PlasmaTemp developed by KLA-Tencor) consisting of an on-board electronics module housing battery power and data storage with 30 temperature sensors embedded onto the wafer at different radial positions. This system allows for real time, in situ wafer temperature measurements. Wafer heating mechanisms were investigated by combining temperature measurements from the PlasmaTemp sensor wafer with a three-dimensional heat transfer model of the wafer and a model of the ICP. Comparisons between pure Ar and Ar/O{sub 2} discharges demonstrated that two additional wafer heating mechanisms can be important in molecular gas plasmas compared to atomic gas discharges. The two mechanisms are heating from the gas phase and O-atom surface recombination. These mechanisms were shown to contribute as much as 60% to wafer heating under conditions of low bias power. This study demonstrated how the 'on-wafer' temperature sensor not only yields a temperature profile distribution across the wafer, but can be used to help determine plasma characteristics, such as ion flux profiles or plasma processing temperatures.

Titus, M. J.; Graves, D. B. [Department of Chemical Engineering, University of California, Berkeley, California 94720 (United States)

2008-09-15T23:59:59.000Z

460

Conductive lithium storage electrode  

DOE Patents (OSTI)

A compound comprising a composition A.sub.x(M'.sub.1-aM''.sub.a).sub.y(XD.sub.4).sub.z, A.sub.x(M'.sub.1-aM''.sub.a).sub.y(DXD.sub.4).sub.z, or A.sub.x(M'.sub.1-aM''.sub.a).sub.y(X.sub.2D.sub.7).sub.z, and have values such that x, plus y(1-a) times a formal valence or valences of M', plus ya times a formal valence or valence of M'', is equal to z times a formal valence of the XD.sub.4, X.sub.2D.sub.7, or DXD.sub.4 group; or a compound comprising a composition (A.sub.1-aM''.sub.a).sub.xM'.sub.y(XD.sub.4).sub.z, (A.sub.1-aM''.sub.a).sub.xM'.sub.y(DXD.sub.4).sub.z (A.sub.1-aM''.sub.a).sub.xM'.sub.y(X.sub.2D.sub.7).sub.z and have values such that (1-a).sub.x plus the quantity ax times the formal valence or valences of M'' plus y times the formal valence or valences of M' is equal to z times the formal valence of the XD.sub.4, X.sub.2D.sub.7 or DXD.sub.4 group. In the compound, A is at least one of an alkali metal and hydrogen, M' is a first-row transition metal, X is at least one of phosphorus, sulfur, arsenic, molybdenum, and tungsten, M'' any of a Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, and VIB metal, D is at least one of oxygen, nitrogen, carbon, or a halogen, 0.0001conductivity at 27.degree. C. of at least about 10.sup.-8 S/cm. The compound can be a doped lithium phosphate that can intercalate lithium or hydrogen. The compound can be used in an electrochemical device including electrodes and storage batteries and can have a gravimetric capacity of at least about 80 mAh/g while being charged/discharged at greater than about C rate of the compound.

Chiang, Yet-Ming (Framingham, MA); Chung, Sung-Yoon (Incheon, KR); Bloking, Jason T. (Mountain View, CA); Andersson, Anna M. (Vasteras, SE)

2012-04-03T23:59:59.000Z