An employee is required to unload 30 cm cardboard cubes from a pallet (15 cm thickness) and place them on a conveyor that is 80 cm high. The cartoons are unloaded at 6 cartons per minute. Each pallet has one layer of cartons containing 16 cartons. The operation requires the worker to twist approximately 900 while turning to unload the cartoon on to the conveyor. A maximum of twelve pallets are unloaded during the first hour of each shift (the activity takes place only once per shift). Find the recommended weight limit for the activity.

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?