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Ethan Merritt wrote:
Back of the lunch-time napkin thought experiment:
100 watt light bulb is exposed to air (essentially nitrogen), losing
heat through radiation and conduction over a surface of 4piR^2 for R
approximately 30 mm. ===> ~ .01 watt per square mm.
The light bulb is hot, according to everyday experience
Say light bulb is 70*, or 50* above ambient
Heat dissipation is limitted by convection in the surrounding air,
100 micron cube protein crystal heated by 2% of a 30 milliwatt
X-ray beam losing heat through conduction over a surface
of 6 x 0.1^2mm ===> ~ .01 watt per square mm.
Crystal is now, one would think, light-bulb temperature.
Crystal might be 50* above ambient, but not light-bulb temperature.
And there is the wind-chill factor from the draft of the cold stream.
Still sounds like significant heating, but it is getting too
close for back-of the napkin calculations.
Ed
