The Heat Conductivity of Rubber at Low Temperatures

1942 ◽  
Vol 15 (1) ◽  
pp. 142-145 ◽  
Author(s):  
Adolf Schallamach
Keyword(s):  
Specific Heat ◽  
Experimental Evidence ◽  
Heat Conductivity ◽  
Low Temperatures ◽  
Vulcanized Rubber ◽  
Sudden Rise ◽  
Volume Relationship ◽  
Lower Temperature ◽  
Relationship Of ◽  
Thin Curve

Abstract The experimental evidence points to the fact that a transition of some kind takes place at about 210° K, which, however, in consequence of supercooling, may take effect at a considerably lower temperature. As is mentioned in the Introduction, there is other evidence of such a transition. The thin curve in Figure 2, which is taken from the paper of Bekkedahl and Matheson, gives the specific heat of amorphous rubber. A sudden rise of this quantity occurs just below 200° K, and we feel sure that this near coincidence is more than accidental. The temperature lag between the two may be accounted for by the fact that Bekkedahl and Matheson worked with pure rubber hydrocarbon, whereas the material used for our investigation was vulcanized rubber. Bekkedahl's experiments on the temperature-volume relationship of various kinds of rubber showed that this transition is shifted towards higher temperatures when the rubber has been vulcanized.

Specific heat of ordered and isotopically disordered lattices

1978 ◽  
Vol 56 (10) ◽  
pp. 1390-1394
Author(s):  
K. P. Srivastava
Keyword(s):  
Specific Heat ◽  
Low Temperatures ◽  
Numerical Study ◽  
Three Dimensional ◽  
Constant Volume ◽  
Nearest Neighbour ◽  
Two Dimensional ◽  
Appreciable Difference ◽  
Substantial Change ◽  
Neighbour Interaction

An extensive numerical study on specific heat at constant volume (Cv) for ordered and isotopically disordered lattices has been made. Cv at various temperatures for ordered and disordered linear and two-dimensional lattices have been compared and no appreciable difference in Cv between these two structures has been observed. Effect of concentration of light atoms on Cv for three-dimensional isotopically disordered lattices has also been shown.In spite of taking next-nearest-neighbour interaction into account, no substantial change in Cv between the ordered and isotopically disordered linear lattices has been found. It is shown that the low lying modes contribute substantially at low temperatures.

Specific heat of the iron-hydrogen system at low temperatures

1979 ◽  
Vol 13 (7) ◽  
pp. 573-575 ◽  
Author(s):  
Hiroaki Wada ◽  
Koshiro Sakamoto
Keyword(s):  
Specific Heat ◽  
Low Temperatures ◽  
Hydrogen System

Study of the low cycle fatigue of 12Cr18Ni10Ti steel based on fractal analysis and artificial intelligence approaches

2021 ◽  
Vol 87 (9) ◽  
pp. 59-67
Author(s):  
A. A. Khlybov ◽  
Yu. G. Kabaldin ◽  
M. S. Anosov ◽  
D. A. Ryabov ◽  
D. A. Shatagin
Keyword(s):  
Neural Network ◽  
Growth Rate ◽  
Fractal Dimension ◽  
Low Temperatures ◽  
Main Crack ◽  
Fatigue Loading ◽  
Wide Range ◽  
Lower Temperature ◽  
Number Of Cycles ◽  
Dimension Index

The evolution of the structure and assessment of the age limit of steel 12Cr18Ni10Ti upon fatigue loading is considered using neural network modeling and approaches of fractal analysis of the microstructure. An algorithm for processing images of the microstructures has been developed to improve their quality. An indicator of the fractal dimension of the image is used as a quantitative indicator for assessing the evolution of the microstructure of the surface metal layer. A quantitative assessment of the structures at different stress amplitudes is carried out in a wide range of low temperatures using the fractal dimension index. Correlation of the fractal dimension index with the run of the sample material is shown. The appearance of the main crack was observed in the range of 0.7 - 0.8 from the number of cycles to failure, after which the crack growth rate increased. At a lower temperature, the main crack is formed later, but further loading results in a higher crack growth rate. Formation of the secondary phases in austenitic steel at a lower temperature occurred at earlier stages than that at a temperature of t = +20°C, which led to hardening of the material. An artificial neural network (ANN) has been developed and trained for assessing structural changes in metal proceeding from the fractal dimensionality of the microstructure images at different stages of fatigue loading. The developed neural network made it possible to estimate with a sufficiently high accuracy the number of cycles before damage of the sample and the residual life of the material. Thus, the developed ANN can be used to assess the current state of the material in a wide range of low temperatures.

Specific heat of single crystal Ba0.6K0.4BiO3 at low temperatures

1996 ◽  
Vol 97 (3) ◽  
pp. 175-178 ◽  
Author(s):  
E.B. Nyeanchi ◽  
D.F. Brewer ◽  
T.E. Hargreaves ◽  
N.E. Hussey ◽  
A.L. Thomson ◽  
...  
Keyword(s):  
Single Crystal ◽  
Specific Heat ◽  
Low Temperatures

Isotopic Thermal Diffusion Factors for Helium and Neon at Low Temperatures

1963 ◽  
Vol 18 (2) ◽  
pp. 242-245 ◽  
Author(s):  
W. W. Watson ◽  
A. J. Howard ◽  
N. E. Miller ◽  
R. M. Shiffrin
Keyword(s):  
Thermal Diffusion ◽  
Low Temperatures ◽  
Quantum Corrections ◽  
Intermolecular Potential ◽  
De Vries ◽  
Lower Temperature ◽  
Improved Accuracy ◽  
Good Agreement

With an all-metal “swing separator” having unique features, thermal diffusion factors αT for He3/He4 and Ne20Ne22 have been measured with improved accuracy down to average gas temperatures T̅=136°K. For helium αT is 0.0696 ± 0.0010 at 136°K, dropping gradually to 0.0651 ±0.0010 at 313°K. These data, plus measurements by Van der Valk and de Vries at somewhat higher temperatures, agree best with values predicted by an exp-six intermolecular potential with ε/k=9.16 and α=12.7. We are extending these helium measurements down to T=4°K for the lower temperature, to detect if possible quantum corrections to the intermolecular potential. For neon αT increases from 0.0166 ± 0.0010 at 136°K to 0.0233 ± 0.0020 at 310°K, considerably higher than our previously reported values. These T. D. factors for neon are in good agreement with values calculated from an exp-six potential with ε/k = 46.0 ± 0.6 and α=13.

Specific Heat Anomalies of PtCo Alloys at Very Low Temperatures

1974 ◽  
pp. 520-524 ◽  
Author(s):  
P. Costa-Ribeiro ◽  
M. Saint-Paul ◽  
D. Thoulouze ◽  
R. Tournier
Keyword(s):  
Specific Heat ◽  
Low Temperatures
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