A 1000 gal vessel, containing air, is to be vacuum purged to a limiting oxygen concentration of 1 ppm. Determine the number of purge cycles required.

T = 75 F
Initial pressure 760 torr
max vacuum 20 mm Hg
Final pressure 1 atm
Purge gas nitrogen
Answer must be the number of purge cycles needed.

Ahouse has the following electrical appliance usage (1) single 40w lamp used for 4 hours per day (2) single 60w fan used for 12 hours per day (3) single 200w refrigerator that runs 24 hours per day with compressor run 12 hours and off 12 hours find the solar power inverter size in watt with correction factor of 1.25.

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

Which of the following components of a pid controlled accumulates the error over time and responds to system error after the error has been accumulated? a)- proportional b)- derivative c)- integral d)- on/off.