A sample of silty sand has a volume of 215 cm3. It has weight of 514.7 g. After saturating the sample the weight is 594.2 g. The sample is then drained by gravity until it reaches a constant weight of 483.4 g. Finally, the sample is dried in an oven for 10 hours, and it reaches the weight of 452.1 g. Assume the density of water is 1 g/cm3. Compute the following: a. Water content
b. Volumetric water content
c. Saturation ratio
d. Porosity
e. Specific yield
f. Specific retention
g. Dry bulk density

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

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?

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.