Thermal Resistance

[KeithB]

While playing with my Prime to answer the previous question, I found that dividing 10_W by 10_degC gives an error.

In high power electronics this is a very common proportionality equivalent to resistance. typically measured in degC/W (though K/W is also used, and probably more correct)

Knowing this proportionality you can calculate the increase of temperature of a device given the power dissipation.

Can we see about adding this to the units calculations? How about a way to add "proportionalities" as some form of user units?