During a compaction test in the geotechnical laboratory, the students compacted a clayey soil into a cylindrical mold 4 in. in diameter and 4.58 in. in height. The compacted soil in the mold weighed 4 lb, and it had a moisture content of 12%. If Gs 5 2.72, determine the following: a. Dry unit weight
b. Void ratio
c. Degree of saturation
d. Additional water (in lb) needed to achieve 100% saturation in the soil 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?