Using the Tafel equation, determine the activation polarization (voltage loss) associated with operation at 50 mA/cm2 and 500 mA/cm2 for: (a) a proton exchange membrane fuel cell with exchange current density of 10-4 A/cm2, and symmetry factor (transfer coefficient) of 0.5, (b) a solid oxide fuel cell with exchange current density of 0.1 A/cm2 and symmetry factor of 0.4. (c) Calculate these same losses using the Butler-Volmer equation. (d) Discuss any differences (or similarities) observed.

Asingle-geared blanking press has a stroke of 200 mm and a rated capacity of 320 kn. a cam driven ram is assumed to be capable of delivering the full press load at constant force during the last 15 percent of a constant-velocity stroke. the camshaft has an average speed of 90 rev/min and is geared to the flywheel shaft at a 6: 1 ratio. the total work done is to include an allowance of 16 percent for friction a) estimate the maximum energy fluctuation b) find the rim weight for an effective diameter of 1.2 m and a coefficient of speed fluctuation of 0.10

Which one from below is not one of the reasons of planning failures? (clo3) a)-planner is careless. b-planner spend less time in the field but more time on the desk c)-planner is not qualified d)-planner does not have sufficient time to properly plan

What are the two (02) benefits, which may result from a successful implementation of preventive maintenance (pm) program in an organization? (clo3)a)- lean manufacturing b)-overlapping responsibilities c)-the planner is not qualified d)-accurate contractor information e)-reduction in equipment redundancies f)-accurate stores information