A closed, rigid tank whose volume is 1.3 m3 contains 3.22 kg of air with the initial conditions of 260 K and 185 kPa. A paddle wheel within the tank does work on the air inside the tank, and 45 kJ of energy escapes through the walls by heat transfer at an average temperature of 285 K. Assuming that air in the tank is an ideal gas with a gas constant of Rair, 1. Determine the final temperature of the air, in K. 2. Determine the heat transfer between the tank contents and the surroundings, in KG.

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?