Schematic of the second example. The cylindrical resistor consists of a nonlinear material (blue) with an inner radius of 0.1 m and an outer radius of 0.3 m. The material is located between two electrodes to which a transient voltage V(t) is applied, where t denotes the time. The resistor is surrounded by a layer of soil (gray) with a thickness of 0.7 m. The inner surface of the resistor and the outer surface of the soil are at a fixed temperature of 60°C and 20°C, respectively. The surrounding space is nonconductive