**1. Introduction**

Drying is defined as the process of vaporising moisture from a material and wiping it away from the surface, sometimes under vacuum, but probably through carrier gas which passes through or over the material. Drying is popularly conceived as water removal into a hot airstream, but drying could include removing any volatile liquid into any heated gas. Through convection, radiation or conduction, or via internal generation such as dielectric or inductive heating, for drying, as defined, to take place, the moist material must obtain heat from its surroundings; the moisture in the body evaporates and the vapour is received by the carrier gas. In **Figure 1**, this drying process is sketched [1].
