Mammalian cells grown in suspension produce waste metabolites such as lactate, alanine, and ammonia, which reduce the yield of cell mass and the desired product on the nutrients supplied. Previous studies (Cruz et al., 1999; Europa et al., 2000; Follstad et al., 1999) have shown that the cells can be made to alter their metabolism by starving them on their nutrients in continuous cultures at lo...

The capacity of computational multiple steady states in two biological systems are determined by the Deficiency One Algorithm and the Subnetwork Analysis. One is a bacterial glycolysis model involving the generation of ATP, and the other one is an active membrane transport model, which is performed by pump proteins coupled to a source of metabolic energy. Mass action kinetics, is assumed and bo...

The dynamics of inequality are studied in a model of human capital accumulation with credit constraints. This model admits a multiplicity of steady state skill ratios that exhibit varying degrees of inequality across households. The main result studies equilibrium paths. It is shown that an equilibrium sequence of skill ratios must converge monotonically to the smallest steady state that exceed...

This paper deals with the analysis of two tubular reactor models, the non isothermal tubular reactor model and a biochemical reactor model. It is shown in particular that multiple equilibrium profiles can be exhibited if the diffusion coefficients are large enough.

In this paper, we extend the MURM (Modified Universe Reaction Model) of a CSTR to a tubular reactor with axial dispersion. Furthermore, we use this mixing model to study the effort of the micromixing on the steady state multiplicity for an autocatalytical reaction of tubular reactor.

Endogenous population growth, i.e., making the rate of population growth dependent on society's opulence, causes parametric changes to have a larger impact and can cause multiplicity of steady states in a dynamic intertemporal optimization framework. This provides a simple explanation for the possibility of differing growth paths between countries (using a standard production function) or anoth...

The phenomenon of capillary condensation is studied through the weight change of condensed phase in an internally wetted porous pd catalyst pellet during the course of exothermic reacation of cyclohexane hydrogenation in a thermogravimetric analyzer (TGA). The direct measurement of condensed phase indicates that evaporation of condensed phase is confined to the macropores of catalyst pellet at ...

The multiplicity of the equilibrium profiles is analyzed for axial dispersion nonisothermal tubular reactors described by Arrhenius type nonlinear models. It is reported that there is at least one steady state among the physically feasible states for such models. Moreover physically meaninful conditions which ensure the multiplicity of equilibrium profiles are given.

Simple distillation columns with ideal vapor-liquid equilibrium may display multiple steady-state solutions. Two fundamentally different sources for the multiplicity are presented. Both bring about the unexpected result that increasing reflux makes separation worse in the top part of the column. It corresponds to an unstable operating point. The first type of multiplicity is found for columns w...