I have some extended aluminum part which is at low temperatures. It is connected by a thin alu rod to a cooling device held at a constant temperature. How can I estimate the rate of cooling through this thin rod given the material specific constants? I assume the heat exchange with the surrounding atmosphere is small, but wouldn't mind including it in my calculations. The Green function is a particle diffusion function. So can I associate the particle/heat speed somehow with a velocity that would give me the "speed of heat"? Then for 1D or 3D I'd calculate the "distance travelled by heat" keeping in mind some diffusion correction depending on the dimension?!