StepWise Transient methodTheoryThe principle of the pulse transient method is shown in Fig. 1. The method can be described as follows. The temperature of the specimen is stabilized and uniform. Then a small disturbance in the form of a heat flux is applied to the specimen. From the temperature response the termophysical parameters can be calculated according to the model used. Fig 1 Experimental set up for stepwise transient method (1) where q=RI^{2} is a heat flux supplied by heat source in the unit area, R is electrical resistance of heat source, I is supplied current, r is density and a, c are unknown thermophysical parameters (thermal diffusivity and specific heat). The temperature function (1) is the solution of the heat equation considering appropriate boundary and initial conditions. Third termophysical parameter, l  thermal conductivity, is defined by wellknown data consistency relation
The thermophysical parameters can be found by superimposing the temperature function (1) on the temperature response by an appropriate fitting technique. The sensitivity coefficients and their crosscorrelation in Fig. 2 give us an overview on the time window in which the fitting technique should be used. There should be a balance between the sensitivity of measured parameters (better for longer time) and their crosscorrelation (better for shorter time).
where p is a parameter to be analysed and T_{i}(t) is the temperature function (1). The crosscorrelation of the sensitivity coefficients b_{ a} and b_{c} of parameters: thermal diffusivity a and specific heat c, is simply defined as
Fig 2. Ideal temperature function T(t), sensitivity coefficients b _{a}(t) and b_{c}(t) of parameters: thermal diffusivity and specific heat, and their crosscorrelation g(t). Ideal model versus real experimentTherefore analysis of differences between ideal model and real experiments has to be
performed that enables to predict disturbing effects in the measuring process.
On the contrary, the real experiment has the following:
Considering some differences stated above, the assumed effects that influence the
The effects are depicted in Fig. 3 as exemplary. The deviations between ideal function
