แห่งดูไบDetermination of foaming properties The foaming process was optimized in terms of maximum foam expansion (i.e., minimum foam density) and maximum foam stability (i.e., minimum drainage volume). Based on these foaming properties, the optimum levels were identified. The foam expansion was measured (Eqn.1) as described by Akiokato, et al [33]: 100 0 10 × − = V VV FE --------- (1)