The natural water content of a series of soil samples taken from the subgrade of a new forest road is to be determined in the laboratory. the samples were sealed in waterproof containers when they were obtained. they were taken to the lab, placed in small water content "tins" and "weighed" on the lab balance [data table below]. the samples were then dried in an oven [104 °c for 24 hours] and reweighed.

sample number 0+52 1+38 2+75 3+62
mass of water content tin, gm 1.47 1.49 1.46 1.47
mass of moist sample plus tin, gm 112.56 98.17 78.56 135.42
mass of dry sample plus tin, gm 91.33 80.48 63.28 113.07

determine the water content of each sample.

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?

Asingle-geared blanking press has a stroke of 200 mm and a rated capacity of 320 kn. a cam driven ram is assumed to be capable of delivering the full press load at constant force during the last 15 percent of a constant-velocity stroke. the camshaft has an average speed of 90 rev/min and is geared to the flywheel shaft at a 6: 1 ratio. the total work done is to include an allowance of 16 percent for friction a) estimate the maximum energy fluctuation b) find the rim weight for an effective diameter of 1.2 m and a coefficient of speed fluctuation of 0.10

Analyze the factors that influence the choice between the following pairs of processes to make the products indicated: i) sand casting versus die casting of an electric-motor housing ii) thread rolling versus machining of a bolt for high-strength application. (co3/c5)