“…This matches the reality of the hydration process, given that the grains, in this process, remain submerged in water throughout the entire diffusion. The condition represented by Equation (4) was used in several works involving the mathematical modeling of diffusion in grains (Coutinho et al, 2010; Hsu, 1983; Nicolin, Coutinho, Andrade, & Jorge, 2013; Nicolin, Coutinho, Andrade, & Jorge, 2012). Equation (5) represents the speed with which the radii of the grains move throughout the drying.…”