where C and Wm are constants determined from the initial portion
of the experimental isotherm; h is the relative pressure defined as
h ¼ p/p0, where p and p0 are the partial and saturated vapor pressure
of water in pa, respectively; and M is the moisture content (%).
Kutarov and Kats (1993) proposed a method to improve the
accuracy of the sorption isotherm of Eq. (5). The new form can be
written as: