Introduction Fuel cells offer the tantalizing promise of cleaner electricity with less impact on the environment than traditional energy conversion technologies. This is because fuel cells are direct electrochemical energy conversion devices. In other words, they convert chemical energy, in the form of a fuel and oxidant, directly into electrical energy. Contrast this to combustion engines, whi...

Thermoelectric generators (TEGs) offer the possibility of extracting electrical power from any heat source, including low-enthalpy heat. The operation thermoelectric is closely related to not only thermal factors but also load conditions. Consequently, simulations TEG-based systems require adequate modeling both and electric phenomena. In this paper, developed TEG model presented verified throu...

a direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. the circuits consist of even harmonic mixers (ehms) realized with antiparallel diode pairs (apdps). we evaluate the different levels of i/q imbalances and dc offsets and use signal space concepts to analyze the bit error rate (ber) of the proposed transceiver using m-ary qam schemes...

three high-silica mordenite zeolites differing in sio440, ratio were prepared by direct synthesis without using any template. the products si02/a120, ratio is influenced by the starting gel composition. this ratio is increased upon ion-exchange with nh,cl and subsequent calcination to prepare protonic mordenite. the protonic mordenites with si02/a1203ra tios of 14.6,29.2 and 34.6 were character...