in this study a simple and general chemical association theory is introduced. the concept of infinite equilibrium model is re-examined and true mole fractions of associated species are calculated. the theory is applied to derive the distribution function of associated species. as a severe test the application of presented theory to the van der waals mixture model is introduced in order to perfo...

In this paper, an SIR epidemic model with an infectious period and a non-linear Beddington-DeAngelis type incidence rate function is considered. The dynamics of this model depend on the reproduction number R0. Accurately, if R0 < 1, we show the global asymptotic stability of the disease-free equilibrium by analyzing the corresponding characteristic equation and using compa...

In this study, liquid-liquid extraction process in a Kuhni extraction column was modeled and simulated. A non-equilibrium dynamic model was developed for modeling liquid-liquid extraction processes based on a rate-based model. The model equations are inclusive of partial and ordinary differential equations which were discretized in column height direction. The population balance model was used ...

In this paper, a five–dimensional mathematical model is proposed for the transmission dynamics of HIV/AIDS within a population of varying size. In writing the model, we have divided the population under consideration into five sub classes of susceptible, infective, pre-AIDS, AIDS related complex and that of AIDS patients. The model has two non- negative equilibria namely, a disease free and the...