The inner surface of a cylindrical pipe with inner radius r0, outer radius r1 is kept at temperatures T0 and outer surface T1. The thermal conductivity of the pipe changes linearly with temperature and takes the values of k0 at T0 temperature and k1 at T1 temperature. Derive a relation based on the general equations for the heat transfer rate at steady state from the inner surface of the pipe of length L. Heat is transferred only in the radius direction.