Thermal Properties of Tungsten SRM’S 730 and 799

1978 ◽  
Vol 100 (2) ◽  
pp. 330-333 ◽  
Author(s):  
R. E. Taylor
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermal Properties ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Standard Material ◽  
International Program ◽  
Sintered Tungsten

Samples of sintered and arc-cast tungsten are available from NBS as thermal conductivity (SRM 730) and electrical resistivity (SRM 799) standards for the temperature range from 4 to 3000K. NBS recommended values for these properties above room temperature are based on results of various researchers during a previous international program which included arc-cast and sintered tungsten. The sintered tungsten used in this program was found to be unsuited for use as a standard material due to inhomogeneity and high temperature instability. The present paper gives results at high temperatures for thermal conductivity, electrical resistivity, specific heat, thermal diffusivity and Wiedemann-Franz-Lorenz ratio for a sample of the NBS sintered tungsten using the Properties Research Laboratory’s multiproperty apparatus. These results are compared to values recommended by the Thermophysical Properties Research Center, NBS, and an international program.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

scholarly journals Thermophysical properties of BiFeO3/REE multiferroics in a wide temperature range

2020 ◽  
Vol 10 (01n02) ◽  
pp. 2060019
Author(s):  
Sidek Khasbulatov ◽  
Suleiman Kallaev ◽  
Haji Gadjiev ◽  
Zairbek Omarov ◽  
Abumuslim Bakmaev ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Rare Earth ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Rare Earth Elements ◽  
Wide Temperature Range ◽  
Thermophysical Properties ◽  
Multiferroic Bifeo ◽  
Comprehensive Study

The paper presents the results of a comprehensive study of the thermophysical properties (thermal conductivity, thermal diffusivity, heat capacity) of high-temperature multiferroic BiFeO3 modified with rare-earth elements (REEs) (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu). The regularities of the formation of the mentioned characteristics were established. The assumptions about the nature of the observed phenomena were suggested.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

Direct Study of the Thermal Conductivity in Aluminum Nanowires

2009 ◽  
Vol 1221 ◽  
Author(s):  
Nenad Stojanovic ◽  
D.H.S. Maithripala ◽  
Jordan M. Berg ◽  
Mark Holtz
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Electrical Resistivity ◽  
Thermal Properties ◽  
Electron Transport ◽  
Theoretical Prediction ◽  
Room Temperature ◽  
Total Thermal Conductivity ◽  
Element Analysis

AbstractThermal conductivity and electrical resistivity of 1 μm long aluminum nanowires, 75, 100, and 150nm in width and 100nm thick, were measured at room temperature. The method consists of microfabricated electrothermal test devices and a model-based data processing approach using finite-element analysis (FEA). The electrical and thermal properties of the nanowires differ significantly from bulk values while electrical resistivity agrees well with theoretical prediction. Electron transport equation models, which adequately describe the resistivity data, consistently underestimate the thermal conductivity. Incorporating a phonon contribution of ˜ 21 W/m·K to the total thermal conductivity is found to accurately describe the measured values.

Determining Thermal Properties of Insulating Sleeves

2010 ◽  
Vol 649 ◽  
pp. 487-491 ◽  
Author(s):  
Witold K. Krajewski ◽  
Józef Szczepan Suchy
Keyword(s):  
Thermal Conductivity ◽  
Mass Transfer ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Boundary Conditions ◽  
Thermophysical Properties ◽  
Mean Values ◽  
Computer Aided ◽  
The Mean

The presented work is aimed at determining thermal diffusivity, thermal conductivity and heat capacity of insulating sleeves used in Polish metallurgical/foundry practice. On basis of the theory elaborated in [1] the mean values of thermophysical properties for temperatures range of about 150-1000 oC were obtained. The results obtained during the examinations presented in the paper can be helpful when formulating boundary conditions during the computer aided simulation of the processes of heat and mass transfer in the system: casting (ingot) – mould riser (ingot head) – ambient, which uses the investigated insulating sleeves [2, 3]. The method of determining thermal properties can be also used for other foundry materials, e.g. sands or cores.

scholarly journals Temperature-dependent thermal properties of spark plasma sintered alumina

2017 ◽  
Vol 49 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Nouari Saheb ◽  
Umer Hayat
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Room Temperature ◽  
Alumina Powder ◽  
Temperature Dependent ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Sintering Method

In this work, we report temperature-dependent thermal properties of alumina powder and bulk alumina consolidated by spark plasma sintering method. The properties were measured between room temperature and 250?C using a thermal constants analyzer. Alumina powder had very low thermal properties due to the presence of large pores and absence of bonding between its particles. Fully dense alumina with a relative density of 99.6 % was obtained at a sintering temperature of 1400?C and a holding time of 10 min. Thermal properties were found to mainly dependent on density. Thermal conductivity, thermal diffusivity, and specific heat of the fully dense alumina were 34.44 W/mK, 7.62 mm2s-1, and 1.22 J/gK, respectively, at room temperature. Thermal conductivity and thermal diffusivity decreased while specific heat increased with the increase in temperature from room temperature to 250?C.

3D Examination of the Thermal Properties of Carbon-Carbon Composites

2014 ◽  
Author(s):  
Melanie Patrick ◽  
Messiha Saad
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermal Characterization ◽  
Flash Method ◽  
Carbon Composites ◽  
Scanning Calorimetry ◽  
Temperature Levels

Thermal characterization of composites is essential for their proper assignment to a specific application. Specific heat, thermal diffusivity, and thermal conductivity of carbon-carbon composites are essential in the engineering design process and in the analysis of aerospace vehicles, space systems and other high temperature thermal systems. Specifically, thermal conductivity determines the working temperature levels of a material and is influential in its performance in high temperature applications. There is insufficient thermal property data for carbon-carbon composites over a range of temperatures. The purpose of this research is to develop a thermal properties database for carbon-carbon composites that will contain in-plane (i-p) and through-the-thickness (t-t-t) thermal data at different temperatures as well as display the effects of graphitization on the composite material. The carbon-carbon composites tested were fabricated by the Resin Transfer Molding (RTM) technique, utilizing T300 2-D carbon fabric and Primaset PT-30 cyanate ester resin. Experimental methods were employed to measure the thermal properties. Following the ASTM standard E-1461, the flash method enabled the direct measurement of thermal diffusivity. Additionally, differential scanning calorimetry was performed in accordance with the ASTM E-1269 standard to measure the specific heat. The measured thermal diffusivity, specific heat, and density data were used to compute the thermal conductivity of the carbon-carbon composites. The measured through-the-thickness thermal conductivity values of all the materials tested range from 1.0 to 17 W/m·K, while in-plane values range from 3.8 to 4.6 W/m·K due to the effect of fiber orientation. Additionally, the graphitized samples exhibit a higher thermal conductivity because of the nature of the ordered graphite structure.

scholarly journals Experimental Investigation on Thermal Conductivity and Thermal Diffusivity of Ex-Vivo Bovine Liver from Room Temperature down to −60 °C

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3750
Author(s):  
Elena Campagnoli ◽  
Valter Giaretto
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Ad Hoc ◽  
Ex Vivo ◽  
Bovine Liver ◽  
Agar Gel ◽  
Calorimetric Analysis ◽  
Temperature Ranges

Ex vivo animal tissues (e.g., bovine liver) as well as water-agar gel are commonly used to simulate both experimentally and numerically the response of human tissues to cryoablation treatments. Data on the low temperature thermal properties of bovine liver are difficult to find in the literature and very often are not provided for the whole temperature range of interest. This article presents the thermal conductivity and thermal diffusivity measurements performed on ex-vivo bovine liver samples using the transient plane source method. Regression coefficients are provided to determine these properties in different temperature ranges except for the phase transition during which no results were obtained, which suggests an ad hoc calorimetric analysis. A quick procedure is also suggested to determine the water mass fraction in the tissue. Moreover, an attempt to estimate the liver density in the frozen state using measurements performed solely at room temperature is also presented. The measured thermal conductivity and thermal diffusivity values are compared with data reported in literature highlighting a spread up to 40%. Moreover, it emerges that water-agar gel usually made with 2% by weight of agar does not show the same thermal properties as the bovine liver.

Thermal Characterization of Carbon-Carbon Composites

2011 ◽  
Author(s):  
Messiha Saad ◽  
Darryl Baker ◽  
Rhys Reaves
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Critical Role ◽  
Carbon Composite ◽  
Flash Method ◽  
Carbon Composites ◽  
Energy Storage Devices ◽  
Graphitized Carbon

Thermal properties of materials such as specific heat, thermal diffusivity, and thermal conductivity are very important in the engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells and solar cells. Thermal conductivity plays a critical role in the performance of materials in high temperature applications. Thermal conductivity is the property that determines the working temperature levels of the material, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this research is to develop thermal properties data base for carbon-carbon and graphitized carbon-carbon composite materials. The carbon-carbon composites tested were produced by the Resin Transfer Molding (RTM) process using T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The graphitized carbon-carbon composite was heat treated to 2500°C. The flash method was used to measure the thermal diffusivity of the materials; this method is based on America Society for Testing and Materials, ASTM E1461 standard. In addition, the differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity was determined using the measured values of their thermal diffusivity, specific heat, and the density of the materials.

Experimental Study on Thermal Properties of Hollow Sphere Structures

2021 ◽  
Vol 407 ◽  
pp. 185-191
Author(s):  
Josef Tomas ◽  
Andreas Öchsner ◽  
Markus Merkel
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Hollow Sphere ◽  
Plane Source ◽  
Source Method ◽  
Transient Plane Source ◽  
Transient Plane Source Method

Experimental analyses are performed to determine thermal conductivity, thermal diffusivity and volumetric specific heat with transient plane source method on hollow sphere structures. Single-sided testing is used on different samples and different surfaces. Results dependency on the surface is observed.

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