We illustrate in the present paper how steady-state and unsteady-steady three-dimensional transport phenomena problems can be solved using the Chebyshev orthogonal collocation technique. All problems are elucidated using the ubiquitous software: MATLAB 1 . The treated case studies include: (1) unsteadystate heat conduction in a parallelepiped body, (2) quenching of a brick, (3) transient diffus...

This paper studies one example of dynamic optimisation of systems subject to hydraulic transportation delays. Properly taking into account the variability of the delay in optimisation is a challenging problem, of importance in several applications. While stationary conditions have been derived in earlier works, here we investigate practical numerical aspects and propose a direct resolution meth...

Department of Chemical Engineering I, Lund Institute of Technology, P.O.Box 124, SE-221 00 Lund, Sweden email: [email protected] URL: http://www.kat.lth.se $EVWUDFW Simulation of chromatography processes is time consuming and specially multi component problems. This paper discusses a MATLAB based simulation toolbox for evaluation of multi component chromatographic processes. Experiences ...

Abstract. Explicit computational formulas for the coefficients of the periodic normal forms for all codim 1 bifurcations of limit cycles in generic autonomous ODEs are derived. They include second-order coefficients for the fold (limit point) bifurcation, as well as third-order coefficients for the flip (period-doubling) and Neimark-Sacker (torus) bifurcations. The formulas are independent of t...

This paper discusses the application of orthogonal collocation on finite elements (OCFE) method using quadratic and cubic B-spline basis functions partial differential equations. Collocation is performed at Gaussian points to obtain an optimal solution, hence name collocation. The used solve various cases Burgers’ equations, including modified equation. KdV–Burgers’ equation considered as a tes...

A numerical method for solving second order, transient, parabolic partial differential equation is presented. The spatial discretization is based on Hermite collocation method (HCM). It is a combination of orthogonal collocation method and piecewise cubic Hermite interpolating polynomials. The solution is obtained in terms of cubic Hermite interpolating basis. Numerical results have been plotte...

Saccharomyces cerevisiae (baker’s yeast) can exhibit sustained oscillations during the operation in a continuous bioreactor that adversely affects its stability and productivity. Because of heterogeneous nature of cell populations, the cell population balance equation (PBE) can be used to capture the dynamic behavior of such cultures. In this work, an unstructured-segregated model is used f...

M. E. Zeynali [email protected] Petrochemical Synthesis Group, Petrochemical Faculty, Iran Polymer and Petrochemical Institute (IPPI), P. O. Box: 14965/115, Tehran, Iran, Abstract In this study the diffusion coefficients for reaction components were determined for unimodal and bimodal pore size distribution and assuming transitional diffusion regime using a more realistic, Stewart-Johnson, m...

A theoretical study of radial flow chromatography was carried out based on a general nonlinear multicomponent rate model which considers radial dispersion. external mass transfer, intraparticle diffusion. and nonlinear multicomponent isotherms. Radial dispersion and mass transfer coefficients were treated as variables which are dependent on the radial coordinate of the radial flow column. The m...