Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 9Citation - Scopus: 11Modeling of Hemodialysis Operation(Springer Verlag, 2010) Abacı, Hasan Erbil; Alsoy Altınkaya, Sacide; Alsoy Altınkaya, Sacide; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, a theoretical model was developed to predict the solute concentrations in patients' blood and optimize the efficiency of the hemodialysis operation. The model takes into account simultaneous mass and momentum transfer on the blood side both in radial and axial directions. A key component of the model is the incorporation of the protein adsorption on the inner surface of the membrane. The validity of the model was confirmed with the experimental data available in the literature for two different types of hemodiafilter. To illustrate the importance of including the radial concentration gradients and protein adsorption kinetics in the model, the experimental data were predicted with and without consideration of these effects. The results have shown that assuming uniform concentration in the radial direction or neglecting protein adsorption on the inner surface of the membrane leads to higher error in predicting the experimental data. In addition, significant error can be introduced in the calculation of the dialysis time if protein adsorption is not considered. © 2010 Biomedical Engineering Society.Article Citation - WoS: 2Citation - Scopus: 1Errors Associated With Swelling in the Analysis of Polymer-Solvent Diffusion Measurements(Elsevier Ltd., 2005) Alsoy Altınkaya, Sacide; Alsoy Altınkaya, Sacide; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologySorption curves are generated from a mathematical model which includes the influence of the polymer swelling for unsteady-state sorption of a vapor or liquid by a polymer. To investigate the simultaneous effects of the specific volumes of the polymer-penetrant pair and the difference between the final and initial equilibrium concentrations on the sorption curves, statistical experimental design approach is used. Simulation results obtained from the numerical solution of model equations are utilized to estimate the error that would occur if one simply evaluates the diffusion coefficient using the traditional formulas derived from the analytical solution of the sorption equation. An empirical expression is developed that describes the effects of the difference between the final and initial equilibrium concentrations and the specific volumes of the polymer and the penetrant on the magnitude of error in diffusivity associated with the use of one of these traditional formulas so called the initial slope method. The predictive ability of the regression model is tested by performing additional simulations not used in the regression analysis.Article Citation - WoS: 24Citation - Scopus: 25Processing of Polymers With Supercritical Fluids(John Wiley and Sons Inc., 1999) Alsoy Altınkaya, Sacide; Alsoy Altınkaya, Sacide; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe removal of impurities, such as residual solvents, unreacted monomers, catalysts, and side-reaction products from polymers represents an important step in polymer processing. Conventional devolatilization techniques for the purification of polymers have limited effectiveness. Devolatilization with supercritical fluids, however, can enhance impurity removal by increasing the thermodynamic driving force and molecular diffusivity.