1. H. S. Carslaw and J. C. Jaeger,Conduction of Heat in Solids(Oxford University Press, London, 1947).
2. An order of magnitude calculation for an aluminum slab which absorbs heat at the rate 105 cal∕cm2-sec in a normal atmosphere yields a surface pressure less than 5 atmos. As the vapor pressure curve for most materials is sufficiently steep near the normal boiling point, an over-pressure of 5 atmos is considered negligible.
3. Conceivably, for a material that vaporizes easily, the steady state may be attained with a surface temperature less than the boiling temperature. However, the steady-state solution obtained in this section indicates that the specification of the maximum possible surface temperature Tυ minimizes the rate of melting. This justifies the procedure when seeking a lower bound.
4. L. L. Quill,The Chemistry and Metallurgy of Miscellaneous Materials(McGraw-Hill Book Company, Inc., New York, 1950).