Superheated steam at 20 mpa, 5608c enters the turbine of a vapor power plant. the pressure at the exit of the turbine is 0.5 bar, and liquid leaves the condenser at 0.4 bar at 758c. the pressure is increased to 20.1 mpa across the pump. the turbine and pump have isentropic efficiencies of 81 and 85%, respectively. cooling water enters the condenser at 208c with a mass flow rate of 70.7 kg/s and exits the condenser at 388c. for the cycle, determine (a) the mass flow rate of steam, in kg/s. (b) the thermal efficiency.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?