Second sound speed in a crystal of NaF at low temperature
Arch. Mech. 49 (1), 189-196, 1997
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Abstract
We derive a physically justifiable model of heat conduction for rigid heat conductors based on a recent approach involving the gradient generalization of an internal state variable. The model accounts for observable phenomena in solid dielectric crystals, related to wave-like conduction of heat in certain ranges of low temperatures and a rapid decay of the speed of thermal waves close to a temperature value ϑλ, at which the conductivity of the material reaches a peak.