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Show - 3 - Various Russian workers have recognized the importance of water vapor transfer to the thermal and mechanical properties of snow, but few reports of definitive studies are available. Many of the papers are speculative. Much of the Soviet thinking along these lines has been summarized for the immediate post- war period by Shakhov ( 6) who presents an extensive bibliography. Probably the most thorough investigation to date, both theoretical and experimental, of the role of water vapor in snow behavior has been that by Yosida and his colleagues ( 7). Rather than measuring A directly, Yosida measured temperature conductivity, K , and found A from the expression A = K/ Cp where c = specific heat of snow In these experiments, snow samples were exposed to sudden temperature changes and a plot obtained of mean sample temperature versus time to determine K. The mean sample temperature was measured by observing changes in pressure of the entrapped air within the sample, A large experimental scatter of A versus p was found, and the following average relation obtainedj lojloA « - 4+ 2p When samples were stabilized at some temperature T]_, changed to a different temperature T2, and then returned again to T-]_, the two values of K thus determined often did not agree. This was attributed to crystalline changes effected by presence of the temperature gradients. |