Heat and Mass Transfer
According of Kirchhoff's law

Emissive power and absorptivity are constant for all bodies
Radiant heat is proportional to fourth power of absolute temperature
Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body
Emissive power depends on temperature

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Heat and Mass Transfer
A steam pipe is to be insulated by two insulating materials put over each other. For best results

Whether to put inferior OIL over pipe or the better one would depend on steam temperature
Inferior insulation should be put over pipe and better one over it
Both may be put in any order
Better insulation should be put over pipe and better one over it

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