A field sample of an unconfined aquifer is packed in a test cylinder. The length and the diameter of the cylinder are 50 cm and 6 cm, respectively. The field sample is tested using pure water (at 20 oC) for a period of 3 min under a constant head difference of 16.3 cm. As a result, 45.2 cm2 of water is collected at the outlet. Determine the hydraulic conductivity of the aquifer sample? On further observation it was noticed that the sample has a median grain size of 0.037 cm and a porosity of 0.30. Evaluate the validity of Darcy’s law?

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?

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

Ifa component is made of two or more materials with different modulus of elasticity (e), it is called a composite member and we calculate the factor·n". mention the formula for calculating n". also, ifn> 1, explain what will happen to the 1. transformed.gi) ifn 1, what will happen to the material when transformed material when