Uploaded by fadare shola matthew


The relationship that exists between materials equilibrium moisture content (Xe) and water
activity (aw) during drying has been established by the Guggenheim–Anderson–de Boer (GAB)
model, represented as:
πΆπΎπ‘Žπ‘€ π‘š0
𝑀 )(1−πΎπ‘Žπ‘€ +πΆπΎπ‘Žπ‘€ )
𝐢0 𝑒π‘₯𝑝 (𝑅𝑇1 )
𝑋𝑒 = (1−πΎπ‘Ž
𝐾 = 𝐾0 𝑒π‘₯𝑝 (𝑅𝑇2 )
where the monolayer water content m0 = 0.06156 kg/kg, heats of sorption of water H1 = 24831
J/mol and H2 = -5118 J/mol, the molar gas constant R =8.314 J/mol/K, the absolute temperature
T = (52.6 + 273.15)K and the constants C0 = 0.001645 and K0 = 5.710.
Use appropriate programming language (Python, C or Java) and numerical approaches
(Bisection, Newton Raphson and Aitken’s Delta Square) to implement the numerical solution
for water activity (0<aw≤1), given that the equilibrium moisture content Xe = 0.133 kg/kg.
Hint: start by converting equation 1 to the form ax2 + bx + c = 0