Composite materials offer the possibility of engineering materials with properties that cannot be achieved using a single material. One such class of materials are metal-filled epoxies that can be used as replacements for pure metal solders or as thermal interface materials to enhance the thermal conductivity in the joint between two elements such as between a transistor and heat sink [44]. Assume we have a metal-filled epoxy material where contact between the metal particles yields an electrical resistivity of \(5 \times 10^{-5} \Omega \mathrm{cm}\) at \(298 \mathrm{~K}\). Assuming the heat will all be transferred by conduction electrons in the metal fraction, provide an estimate for the thermal conductivity of the composite.