(a) Describe the features that one desires when selecting a fuel cell electrode material. Describe and illustrate both features of electrode structure and properties as well as interactions between the electrodes and other fuel cell components (e. g., reactant gases, electrolyte, product gases, interconnects). Identify some specific electrode materials and why they work well for a (b) PEMFC and (c) SOFC, respectively

Aleaky 10-kg bucket is lifted from the ground to a height of 15 m at a constant speed with a rope that weighs 0.7 kg/m. initially the bucket contains 45 kg of water, but the water leaks at a constant rate and finishes draining just as the bucket reaches the 15-m level. find the work done. (use 9.8 m/s2 for g.) show how to approximate the required work by a riemann sum. (let x be the height in meters above the ground. enter xi* as xi.) lim n → ∞ n (9.8)(45−3 xi) i = 1 δx express the work as an integral. 0 dx evaluate the integral. (round your answer to the nearest integer.) j