“…(10) However, a non linear behavior appears at small current and high transitions times. In accordance with Krol et al [17] this behavior is due to the imposed current, next to the limit value, does not allow the semi infinite diffusion condition needed to deduce the Sand's equation, so the diffusion layer has a finite size. Even in these conditions a finite layer can be resembled to an infinite layer if several conditions happen involving an upper limit above the transition times, and for a system with forced convention, the concentration in the polarization layers would not change for (2Dτ) However, heterogeneous membranes consist of conducting and not conducting regions.…”