e parameters are calculated for each material, the thermal diffusivity
    constant and Fourier number for the transition regions (A-B, B-A) are
    determined. For transition Region AB, the following equations are used:

    $$\alpha_{AB} = \frac{\left(\frac{k_B*dx_B + k_A*dx_A}{dx_B + dx_A}\right)}{\rho_A*Cp_A}$$
    $$Fo_{AB} = \frac{dt* \alpha_{AB}}{dx_A * \left(\frac{dx_A+dx_B}{2}\right)}$$

    For Region BA, the above equations are used, but the values for <i>k</i>,
    <i>Cp</i>, etc. of Material A 