Mathematical modeling of crossflow microfiltration of diluted malt extract suspension by tubular ceramic membranes

The practical application of microfiltration in brewing industry is hindered by severe membrane fouling and subsequent permeate flux decline. A theoretical and experimental study on the effect of operating parameters, which influence the crossflow microfiltration of beer and beer quality was performed. A mathematical model is developed to better understanding of the fouling layer characteristics. The experiments were conducted for different ranges of pressures, temperatures and shear rates. An optimum transmembrane pressure of 1.1 bar is suggested to maximize both the steady state and average permeate fluxes. The results of numerical simulation were in a good accordance with the experimental data.     

Buckling analysis of stepped plates using modified buckling mode shapes

A new approximate procedure for buckling analysis of simply supported rectangular stepped or perforated plates subjected to uniform edge stresses is formulated. The procedure uses energy method based on modified buckling mode shapes. The change of thickness within a plate is characterized by introducing a stepping index. It is shown that the buckling (vibrational) mode shapes of stepped plates can be predicted by linear combination of various mode shapes of the equivalent flat plates. These buckling mode shapes, in turn, are incorporated to evaluate buckling loads of stepped plates. Some case studies are carried out to demonstrate the accuracy and the versatility of the proposed method by comparing them to the results presented by other researchers.     

A mathematical model for assessing the effects of a lot splitting feature on a dynamic cellular manufacturing system

Numerous studies have been carried out in the field of cellular manufacturing systems (CMS) by considering different types of production costs. In all the presented models, it has been assumed that either the production lot of a part type should be processed by only one machine or it can be split among several machines. To the best of our knowledge, there is no research considering the advantages and disadvantages of the lot splitting feature in designing a CMS under a dynamic environment. In this paper, a mixed-integer nonlinear programming model is formulated to design a dynamic CMS by considering the burdened costs of processing part operations, idleness of cells and machines, inter-cell movements, installation/uninstallation of machines, machine overhead, production lost, splitting production lots and dispersing machines among cells. Furthermore, the advantages and disadvantages of the lot splitting feature are investigated by regarding its effect on the burdened costs. After linearization, an illustrative numerical example is solved by GAMS software (CPLEX solver) to illustrate the model performance and analyze the effect of the lot splitting feature. Since the given problem is NP-hard, an efficient simulated annealing algorithm is developed and tested using several test problems.     

Numerical solution of doubly singular nonlinear systems using neural networks-based integrated intelligent computing

Neural Computing and Applications - In this paper, a bio-inspired computational intelligence technique is presented for solving nonlinear doubly singular system using artificial neural networks...