Sharif Digital Repository

Finding the optimal flow pattern in bipolar plates of a proton exchange membrane is a crucial step for enhancing the performance of the device. This design plays a critical role in fluid mass transport through microporous layers, charge transfer through conductive media, management of the liquid water produced in microchannels, and microporous layers and heat management in fuel cells. This article investigates different types of common flow patterns in bipolar plates while considering a uniform pressure and velocity distribution as well as a uniform distribution of reactants through all the surfaces of the catalyst layer as the design criteria so that there would be a consistent electron... 

Radio Frequency Identification (RFID) is an easy to use technology for quick and low-cost identification and authentication. Since RFID systems have found in various parts of our daily lives, security awareness about these systems has become one of the prominent topics for researchers. In this study, we investigate two RFID security schemes which both are under Electronic Product Code (EPC) standard. It is shown that both the analyzed protocols have some drawbacks and are vulnerable to several security attacks including secret parameters reveal, impersonation, reader forward secrecy and also one of them does not provide date integrity. In addition, in order to overcome all the discovered...