A120 cy per hr maximum output pump is used to place the concrete for a 200 cy slab. the concrete is supplied by 8 cytransit-mix trucks arriving to the site on 12 min intervals. the concrete batch plant is located 5 miles from the site. averagetruck speed is 30 mph. each transit-mix truck takes, on average, 10 min to discharge. the placement crew size is 7 workers. average worker output is 5 cy of concrete per hr. (a) how long will the operation take? (b) how can the operation bereorganized more effectively?

What difference(s) did you notice using a pneumatic circuit over hydraulic circuit.explain why the pneumatic piston stumbles when it hits an obstacle.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Compute the pressure drop of 30°c air flowing with a mean velocity of 8 m/s in a circular sheet-metal duct 300 mm in diameter and 15 m long. use a friction factor, f 0.02, and pair = 1.1644 kg/m a. 37.26 pa b. 25.27 pa n c. 29.34 pa d. 30.52 pa