Thermal Conductivity Lambda Research Articles

Thermal recovery of the skin after cooling

A theoretical model of the skin is used to study the thermal recovery of the skin temperature after cooling. The analytical solution of the partial differential equation describing this model shows that recovery curves can be approximated by a two-exponential curve or even by a mono-exponential curve when the data from the first two minutes are omitted. With this model, it is possible to study the influence of the blood flow and the thermal conductivity lambda of the skin on the steady-state temperature and the decay constants mu n. New experiments will be carried out to verify the relation between mu 1, mu 2 and the blood flow but now correcting for the influence of lambda , as predicted by the model.

The thermal conductivity of four solid phases of NH4F, and a comparison with H2O

The thermal conductivity lambda has been measured for solid phases I to IV of NH4F, and the authors have found significant similarities with previous measurements of this quantity for H2O. This is discussed in relation to the corresponding phase diagrams and crystal structures.

The thermal properties of an epoxy resin at high pressure and temperature

The thermal conductivity lambda , thermal diffusivity and heat capacity per unit volume has been measured for an epoxy resin, Araldite AW 106, with hardener HV 953 U. Measurements have been carried out at room temperature up to 2.5 GPa and between 300 and 430K at 0.11 and 0.27 GPa. The glass transition temperature and its pressure (P) dependence have been determined. The quantity delta lambda / delta P was found to change abruptly in the temperature region of the glass transition.

The Righi-Leduc and Hall coefficients of Ag alloys

It has been shown by Tsuji that the Righi-Leduc coefficient of metals should be reduced by a factor ( lambda e/ lambda m)2 where lambda e and lambda m are the electronic and total (measured) thermal conductivities. The authors have measured the variation of the Righi-Leduc and Hall coefficients as a function of temperature over the range 2.5-120 K for three dilute Ag alloys containing a nominal 1 at% of Au, Cd and In respectively. In the regime where the electronic scattering can be considered to be elastic, they show that Tsuji's result can be used to evaluate the lattice thermal conductivity lambda g and that the results so derived are in excellent agreement with estimates made by standard techniques. The results also confirm that the Righi-Leduc and Hall coefficients are related by the Lorenz number in the elastic scattering limit, as expected.