The walls of a furnace are made of 1.6-ft-thick concrete (k = 0.64 btu/h⋅ft⋅°f and α = 0.023 ft2/h). initially, the furnace and the surrounding air are in thermal equilibrium at 70°f. the furnace is then fired, and the inner surfaces of the furnace are subjected to hot gases at 1800°f with a very large heat transfer coefficient. determine how long it will take for the temperature of the outer surface of the furnace walls to rise to 70.1°f.

If the thermal strain developed in polyimide film during deposition is given as 0.0044. assume room temperature is kept at 17.3 c, and thermal coefficient of expansion for the film and the substrate are 54 x 10^-6c^-1 and 3.3 x 10^-6c^-1respectively. calculate the deposition temperature.

Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.

Which of the following controllers anticipates the future from the slope of errors over time? a)-proportional b)-on/off c)-integral d)-derivative.