Assume that the flowrate. Q, of a gas from a smokestack is a function of the density of the ambient air, rhoarho a , the density of the gas, rhogrho g , within the stack, the acceleration of gravity, g, and the height and diameter of the stack, h and d, respectively. Use rhocrho c , d, and g as repeating variables to develop a set of pi terms that could be used to describe this problem.

On a average work day more than work place firs are reorted

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0