A Reverse Logistics Network Model for Handling Returned Products

58827Due to the emergence of e-commerce and the proliferation of liberal return policies, product returns have become daily routines for many companies. Considering the significant impact of product returns on the company’s bottom line, a growing number of companies have attempted to streamline the reverse logistics process. Products are usually returned to initial collection points (ICPs) in small quantities and thus increase the unit shipping cost due to lack of freight discount opportunities. One way to address this issue is to aggregate the returned products into a larger shipment. However, such aggregation increases the holding time at the ICP, which in turn increases the inventory carrying costs. Considering this logistics dilemma, the main objectives of this research are to minimize the total cost by determining the optimal location and collection period of holding time of ICPs; determining the optimal location of a centralized return centre; transforming the nonlinear objective function of the proposed model formulation by Min et al. (2006a) into a linear form; and conducting a sensitivity analysis to the model solutions according to varying parameters such as shipping volume. Existing models and solution procedures are too complicated to solve real-world problems. Through a series of computational experiments, we discovered that the linearization model obtained the optimal solution at a fraction of the time used by the traditional nonlinear model and solution procedure, as well as the ability to handle up to 150 customers as compared to 30 in the conventional nonlinear model. As such, the proposed linear model is more suitable for actual industry applications than the existing models.S

Low temperature dye-sensitized solar cells based on conformal thin zinc oxide overlayer on mesoporous insulating template by atomic layer deposition

Low temperature processing of Dye-sensitized Solar Cells (DSCs) is essential to enable commercialization with low cost plastic substrates and diminish the overall manufacturing cost. We report a low temperature processing route for photoanodes where thin ZnO nanoshell is deposited by atomic layer deposition at 150 degrees C, on a mesoporous insulating template. We found that a 6 nm ZnO overlayer on a 3 mu m mesoporous nanoparticle Al2O3 template shows a power conversion efficiency of 4.3% with the standard organic sensitizer (coded Y123) and cobalt bipyridine redox mediator. (C) 2014 Sharif University of Technology. All rights reserved

Controlled synthesis of TiO2 nanoparticles and nanospheres using a microwave assisted approach for their application in dye-sensitized solar cells

Rapid and facile synthesis of similar to 7 nm and similar to 100-400 nm nano-structures of anatase titania is achieved by exploiting the chemical nature of solvents through a microwave based approach. After using these nanostructures as a photoanode in dye-sensitized solar cells, a modest yet appreciable efficiency of 6.5% was achieved under the illumination of AM 1.5 G one sun (100 mW cm(-2))