In the current study, the morphology including tortuosity, and the permeability of 50-mm thick commercially available 30, 40, 50, and 80 pores per inch (PPI) alumina ceramic foam filters (CFFs) have been investigated. Measurements have been taken of cell (pore), window, and strut sizes, porosity, tortuosity, and liquid permeability. Water velocities from~0.015 to 0.77 m/s have been used to derive both first-order (Darcy) and second-order (Non-Darcy) terms for being used with the Forchheimer equation. Measurements were made using 49-mm ''straight through'' and 101-mm diameter ''expanding flow field'' designs. Results from the two designs are compared with calculations made using COMSOL 4.2a Ò 2D axial symmetric finite element modeling (FEM), as a function of velocity and filter PPI. Permeability results are correlated using directly measurable parameters and compared with the previously published results. Development of improved wall sealing (49 mm) and elimination of wall effects (101 mm) have led to a high level of agreement between experimental, analytic, and FEM methods (±0 to 7 pct on predicted pressure drop) for both types of experiments. Tortuosity has been determined by two inductive methods, one using cold-solidified samples at 60 kHz and the other using liquid metal at 50 Hz, giving comparable results.

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This study aims to investigate the limitations and applicability of different ion exchanged zeolites as antimicrobial additive in thermoplastic polyether type polyurethanes. These composites were designed to improve the health quality of hospitalized patients by expressing both biocompatibility and relevant antimicrobial activity. The zeolites were exchanged with silver, copper and zinc ions and single, binary and ternary ion-exchanged zeolite-polyurethane composites were prepared. The antimicrobial activity and the resistance of the composites against the human environment play vital role in the applicability of the materials as a medical device therefore these properties were investigated. The antimicrobial test were performed on Methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa and Candida tropicalis. The tests showed that the efficiency of the silver ions is superior to the other single ionic systems. Besides, the binary and ternary ion-exchanged samples had similar antimicrobial efficiency regardless the type of the ions in the zeolite. The biocompatibility tests were carried out in-vitro in artificial body fluids for a period of 12 weeks. As a result of the invitro test, degradation of the composites were observed and the structural changes of the materials were detected and described by Scanning Electron Microscopy, Contact Angle measurements and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy

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