An air-standard cycle with variable specific heats is operated in a closed system with the following 4 processes 1-2) constant-volume heat addition from 14 psia and 80°f to 50 psia. 2-3) constant-pressure heat addition to 2240°f. 3-4) isentropic expansion to 14 psia. 4-1) constant-pressure heat rejection to the initial state a. draw the cycle on p-v and t-s diagrams. b. calculate the net work output per mass of air. ( 107.9 btu/lbm) c. determine the thermal efficiency.

Which of the following ziegler nichols tuning methods the response of the controller to a step input should exhibit an s-shaped curve? a)-open loop mode b)-closed loop mode c)-both modes (open & closed) d)-none of the modes (open & closed)

Vibration monitoring this technique uses the noise or vibration created by mechanical equipment and in seme cases by plant systems to detemine their actual condtion. a)- true b)- false

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.