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Author: canucme
Time: 12/21/99 15:55 PST
This is a reply to message no. 5 by jmliao
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Current Topic:
radiation teaser
To mimic a bald head exposed to the cold night sky, try these values:

Object 1 (Bald Head)
Temp:  95 deg F
Area:  0.3 ft^2 (a reasonable guess)
Emissivity:  0.9 (another reasonable guess)

Object 2 (night sky)
Temp:  -150 deg F
Area:   anything much larger than the area of object 1
Emissivity:  1 (sky acts like a blackbody)

ViewFactor:  1  (assume that the head sees nothing but sky)

This will give a heat loss of almost 12 watts, a reasonable estimate for this problem.  The earlier suggestion of 20 watts was probably an overestimate; object 1's area was chosen too large.
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