Sharif Digital Repository

Fuel cells convert the chemical energy of hydrogen and oxygen directly into the electricity. Their high efficiency and low emissions have made them a prime candidate for powering the next generation electric vehicles. Polymer electrolyte membrane is a key component of the PEM fuel cells. One of the critical problems to overcome in some PEM fuel cells is the water management because If there is not enough water, the membrane becomes dehydrated which leads to a rapid increase in ohmic resistance. On the other hand, if too much water is present, flooding may occur resulting in the pores of the gas diffusion filled by water and the available passage for reactant gases is decreased. In this work... 

Polarization-sensitive optical coherence tomography is a non-invasive imaging technique that is capable of producing two-dimensional or three-dimensional images using the additional properties of light, as well as qualitative examination of the sample. This system, like optical coherence tomography, is mainly used in ophthalmology as a powerful tool for the early detection of eye diseases. PS-OCT can obtain high-resolution cross-sectional images of ocular fibrous structures, such as the retina or anterior segment, which show birefringence when injured. The main purpose of this dissertation is to develop an analytical model of system layout to study important parameters such as birefringence....