Fractional thermal systems

We investigate the fractional behavior of the integrators associated with a fractional diffusion equation in an interface, in two different geometries, a wall and a sphere, by means of a new relation between Caputo derivatives and non integer integrators. The behavior of such integrators is shown using Bode diagrams calculated for a limited spectral range. At high frequencies, the fractional behavior is approximated by a non integer order integrator. As a particular case we recover some recent results.