Sharif Digital Repository

The fire event may cause danger to life and property. In general, most fire-detection devices are set on the wall or ceiling. . However, this method is not flexible enough to detect a fire occurrence, and this needs the use of many fire-detection devices in a building. Since it is not suitable, we use an active fire-detection device to detect a fire incident. In the past, smoke sensors were used for fire detection, but often the smoke sensors triggered a false alarm when someone smoked in the room. Therefore, multisensor fire-detection methods are one of the current important developments for fire- detection technology. We design a fire-detection module using an ionization smoke sensor... 

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...