The time variation of temperature profile along the sample for
different positions (center and surface) is shown in Fig. 8a. The temperature distribution increases all the time from the surface to the
centre of the sample. As the drying time progresses, the temperature
gradient decreases until a steady stage is reached, in which heat gain
due to convective boundary condition balances the heat transfer
through conduction (Janjai et al., 2008; Villa-Corrales et al., 2010;
Wu et al., 2004). Fig. 8b shows the moisture ratio at the centre and
at the surface of the sample object subjected to drying