The relative compaction of a clayey sand in the field is 90%. The maximum and minimum dry unit weights of the sand are 115 lb/ft3 and 93 lb/ft3, respec- tively. Determine: a. Dry unit weight in the field b. Relative density of compaction c. Moist unit weight at a moisture content of 18%

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?

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

The higher the astm grain size number, the finer the gran is. a)-true b)-false