scholarly journals A Lecture Experiment on the Relative Thermal Conductivities of Various Metals

Nature ◽  
1899 ◽  
Vol 60 (1550) ◽  
pp. 244-245 ◽  
Author(s):  
EDWIN EDSER
Keyword(s):  
Lecture Experiment ◽  
Thermal Conductivities

WIELAND-K32

Alloy Digest ◽  
2005 ◽  
Vol 54 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Electrical Engineering ◽  
Heat Treating ◽  
Power Cables ◽  
Bend Strength ◽  
Thermal Conductivities

Abstract Wieland-K32 is a nondeoxidized copper with acceptable electrical and thermal conductivities. It is often called electrolytic tough pitch copper. Typical applications include wrapping strip for power cables and for coaxial telephone cables in electrical engineering. This datasheet provides information on composition, physical properties, elasticity, and bend strength. It also includes information on corrosion resistance as well as heat treating and joining. Filing Code: CU-728. Producer or source: Wieland Metals Inc.

PD-135

Alloy Digest ◽  
1972 ◽  
Vol 21 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Thermal Conductivities

Abstract PD-135 is an oxygen-free, age-hardenable copper containing chromium and cadmium. It has excellent mechanical properties and high electrical and thermal conductivities. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-261. Producer or source: Phelps Dodge Copper Products Company.

THE EFFECTS OF STRATIGRAPHY AND COAL AND SHALE THERMAL CONDUCTIVITIES ON TEMPERATURES GRADIENTS IN THE PICEANCE BASIN, COLORADO, USA

2016 ◽  
Author(s):  
Zachary Souvall ◽  
◽  
Allison Keator ◽  
Molly Baron ◽  
Paul Morgan ◽  
...  
Keyword(s):  
Piceance Basin ◽  
Thermal Conductivities

scholarly journals Lightweight Cement Conglomerates Based on End-of-Life Tire Rubber: Effect of the Grain Size, Dosage and Addition of Perlite on the Physical and Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 225
Author(s):  
Andrea Petrella ◽  
Michele Notarnicola
Keyword(s):  
Grain Size ◽  
End Of Life ◽  
Compression Tests ◽  
Tire Rubber ◽  
Impact Compression ◽  
Weight Percentage ◽  
Deep Groove ◽  
Mechanical Strengths ◽  
The Impact ◽  
Thermal Conductivities

Lightweight cement mortars containing end-of-life tire rubber (TR) as aggregate were prepared and characterized by rheological, thermal, mechanical, microstructural, and wetting tests. The mixtures were obtained after total replacement of the conventional sand aggregate with untreated TR with different grain sizes (0–2 mm and 2–4 mm) and distributions (25%, 32%, and 40% by weight). The mortars showed lower thermal conductivities (≈90%) with respect to the sand reference due to the differences in the conductivities of the two phases associated with the low density of the aggregates and, to a minor extent, to the lack of adhesion of tire to the cement paste (evidenced by microstructural detection). In this respect, a decrease of the thermal conductivities was observed with the increase of the TR weight percentage together with a decrease of fluidity of the fresh mixture and a decrease of the mechanical strengths. The addition of expanded perlite (P, 0–1 mm grain size) to the mixture allowed us to obtain mortars with an improvement of the mechanical strengths and negligible modification of the thermal properties. Moreover, in this case, a decrease of the thermal conductivities was observed with the increase of the P/TR dosage together with a decrease of fluidity and of the mechanical strengths. TR mortars showed discrete cracks after failure without separation of the two parts of the specimens, and similar results were observed in the case of the perlite/TR samples thanks to the rubber particles bridging the crack faces. The super-elastic properties of the specimens were also observed in the impact compression tests in which the best performances of the tire and P/TR composites were evidenced by a deep groove before complete failure. Moreover, these mortars showed very low water penetration through the surface and also through the bulk of the samples thanks to the hydrophobic nature of the end-of-life aggregate, which makes these environmentally sustainable materials suitable for indoor and outdoor elements.

scholarly journals Evolution regularity of temperature field of active heat insulation roadway considering thermal insulation spraying and grouting: A case study of Zhujidong Coal Mine, China

2021 ◽  
Vol 40 (1) ◽  
pp. 151-170
Author(s):  
Weijing Yao ◽  
Happiness Lyimo ◽  
Jianyong Pang
Keyword(s):  
Sensitivity Analysis ◽  
Temperature Field ◽  
Thermal Insulation ◽  
Wall Temperature ◽  
Heat Insulation ◽  
Surrounding Rock ◽  
Rock Temperature ◽  
Grouting Materials ◽  
Zone Radius ◽  
Thermal Conductivities

Abstract To study the active heat insulation roadways of high-temperature mines considering thermal insulation and injection, a high-temperature −965 m return air roadway of Zhujidong Coal Mine (Anhui Province, China) is selected as a prototype. The ANSYS numerical simulation method is used for the sensitivity analysis of heat insulation grouting layers with different thermal conductivities and zone ranges and heat insulation spray layers with different thermal conductivities and thicknesses; thus, their effects on the heat-adjusting zone radius, surrounding rock temperature field, and wall temperature are studied. The results show that the tunneling head temperature of the Zhujidong Mine is >27°C all year round, consequently causing serious heat damage. The heat insulation circle formed by thermal insulation spraying and grouting can effectively alleviate the disturbance of roadway airflow to the surrounding rock temperature field, thereby significantly reducing the heat-adjusting zone radius and wall temperature. The decrease in the thermal conductivities of the grouting and spray layers, expansion of the grouting layer zone, and increase in the spray layer thickness help effectively reduce the heat-adjusting zone radius and wall temperature. This trend decreases significantly with the ventilation time. A sensitivity analysis shows that the use of spraying and grouting materials of low thermal conductivity for thermal insulation is a primary factor in determining the temperature field distribution, while the range of the grouting layer zone and the spray layer thickness are secondary factors. The influence of the increased surrounding rock radial depth and ventilation time is negligible. Thus, the application of thermal insulation spraying and grouting is essential for the thermal environment control of mine roadways. Furthermore, the research and development of new spraying and grouting materials with good thermal insulation capabilities should be considered.

scholarly journals Prediction of Effective Thermal Conductivities of Four-Directional Carbon/Carbon Composites by Unit Cells with Different Sizes

2021 ◽  
Vol 11 (3) ◽  
pp. 1171
Author(s):  
Chang Xu ◽  
Zhihong Sun ◽  
Guowei Shao
Keyword(s):  
Carbon Fiber ◽  
Longitudinal Direction ◽  
Unit Cell ◽  
Carbon Composites ◽  
Temperature Boundary ◽  
The Matrix ◽  
Unit Cells ◽  
Experimental Values ◽  
Different Diameters ◽  
Thermal Conductivities

Two-unit cells developed to predict the effective thermal conductivities of four-directional carbon/carbon composites with the finite element method are proposed in this paper. The smaller-size unit cell is formulated from the larger-size unit cell by two 180° rotational transformations. The temperature boundary conditions corresponding to the two-unit cells are derived, and the validity is verified by the temperature and heat flux distributions at specific positions of the larger-size unit cell and the smaller-size unit cell. The thermal conductivities of the carbon fiber bundles and carbon fiber rods are measured firstly. Then, combined with the properties of the matrix, the effective thermal conductivities of the four-directional carbon/carbon composites are numerically predicted. The results in transverse direction predicted by the larger-size unit cell and the smaller-size unit cell are both higher than experimental values, which are 5.8 to 6.2% and 7.3 to 8.2%, respectively. In longitudinal direction, the calculated thermal conductivities of the larger-size unit cell and the smaller-size unit cell are 6.8% and 6.2% higher than the experimental results, respectively. In addition, carbon fiber rods with different diameters are set to clarify the influence on the effective thermal conductivities of the four-directional carbon/carbon composites.

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