Simultaneous determination of thermal conductivity and diffusivity of porous materials

The theory of temperature variation at any point in an infinitely extending medium containing an infinitely long thin conducting wire, heated periodically, is applied to a probe having finite dimensions and thermal properties. The conditions for a minimal effect due to finite dimension of the medium and contact resistance between the probe and medium are discussed. The results of thermal conductivity and diffusivity, thus obtained, are reported. The thermal probe method under periodic conditions gives satisfactory results.