Polysulfone ultrafiltration membranes were fabricated using various sizes (20, 40, and 90–210 nm) of silver nanoparticles (nAg) blended in a dope solution. To characterize the performance and properties of the prepared membranes, scanning electron microscopy (SEM), water contact angle, protein separation, water flux, and antibacterial tests were conducted. The characterization results revealed that when nAg particles (20 nm) were blended into the base polymer PSF, the PSF/nAg blended membrane had the lowest contact angle (58.5°) and surface energy (110.7 mN/m). When experimenting with ultrafiltration using protein solutions, bare PSF and PSF/nAg-20 blended membranes gave similar values of protein rejection: 93% of bovine serum albumin (BSA) and 70% of lysozyme rejection. Furthermore, SEM studies showed that the surface pore size was reduced by adding 20 nm nAg particles in the casting solution. Most importantly, the introduction of 40 nm nAg particles reduced the growth of bacterial colonies on the membrane surface by up to 72%. These findings revealed that nAg particles are expected to be a potential modifier for the fabrication of an ultrafiltration membrane.

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In practice, a vendor may offer a retailer an advance-cash-credit (ACC) payment scheme. This implies the buyer needs to pay a fraction of the purchasing cost before he receives the item (advance payment), some cash when the item is arrived (cash on delivery), and then the remaining purchasing cost after a credit period (credit payment). This paper studies the effect of payment schemes on the supply chain network design. The network consists of an outside supplier, multiple distribution centers (DCs), and multiple retailers. The DCs receive an upstream ACC payment from the supplier. This study attempts to determine the optimal location, allocation, as well as the inventory cycle time while minimizing total cost. A continuous approximation is used in the model development and the time value of money concept is considered, since different payment schemes related to time change the cash value. Numerical studies are adopted to demonstrate the solution approach and the effects of changing parameters on decisions and total cost. This study provides novel management implications for supply chain network designers' reference. The results show that the number of DCs to be opened, the joint replenishment cycle time of DC, and the total cost increase as the interest earned decreases and the interest charged increases.