heat-transfer.tcl   	version 0.9		June 26, 1998
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The heat-transfer program is a tool to help people understand how heat is 
moved from object to object.  The user places various materials on a 
sqare grid, giving each a starting temperature.  The user is then given a 
grapihcal representation of the temperature changes.  The program can 
easily show, for example, that the temperature of gold changes much 
faster than the temperature of rubber.

The numerical method used in the software is described in the reference 
given below. Basically, the method has the following features: second-order
accurate in both space and time, stable for any size of time step, accurate
in the treatment for interfaces between materials, conservative and
iterative. Numerical errors undergo quick damping when the size of time  
step is very large. [1] W. Dai and P. R. Woodward, Numerical simulations 
for nonlinear heat transfer in systems of multi-materials, J. of Comput. 
Phys., vol.139, pp.58-78, 1998. 

