Through optimiz- ing geometry the metal lead effect due to heat generation and heat conduction could be minimized to enhance the cooling perfor- mance. Yovanovich [14] and Desai et al. [15] developed the general solution for thermal spreading resistance of one and multiple cylindrical solids, respectively, by using Fourier–Bessel functions expansion. When the cylinder is very long and side cooling is small, the general relationship reduces to the case of an extended surface with end cooling and spreading resistance at the base. They also applied their analytic model to the simulation of a nanotube or nanocylinder connecting a region of the chip to a region of the heat sink. Culham et al.