Pressure Drop

The pressure drop caused by vapor flow across the ice-free layers in a slab is proportional to dZ/dt. Consequently, it can be shown that

where Ps is the pressure at the sublimation interface, Pa the pressure at the outer surface of the slab, and K is the permeability of the porous ice-free layers, /f is proportional to the volume fraction of ice initially present, roughly inversely proportional to ice-crystal diameter, increases somewhat as the mean partial pressure of water in the pores increases, and decreases if excessive amounts of non-condensibles are present. Typical K range between 0.7 x 10"9 and 10 x MT9 kg • m"1 • s"1 • (/an Hg)"1 (5 x 10~9 to 70 x 10~9 s-1 in SI units).

Homemade Pet Food Secrets

Homemade Pet Food Secrets

It is a well known fact that homemade food is always a healthier option for pets when compared to the market packed food. The increasing hazards to the health of the pets have made pet owners stick to containment of commercial pet food. The basic fundamentals of health for human beings are applicable for pets also.

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