the earth’s gravity field dedicated missions, champ, grace and goce have opened up a new era for the study of the earth’s gravity field. the missions measure different functionals on the earth’s gravitational potential which are represented in terms of the stokes coefficients or the so-called geopotential models. the mapping process of the observations into the coefficients is called recovery o...

in this research the simulation of an air independent proton exchange membrane fuel cell (pemfc) propulsion system was taken into consideration. the system consists of several parts including pem fuel cell stack, metal hydride and liquid oxygen (lox) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. the heat recovery...

Energy Recovery Battery Testing Systems (ERBTS) plays an important role in battery manufacture. The conventional ERBTS configuration contains a fundamental transformer, and a bidirectional Direct Current (DC)–DC and Alternating Current (AC)–DC converter. All ERBTS are connected in parallel, thus constituting a special and complicated AC micro-grid system. Aiming at addressing their low energy r...