A Ground water was anaylzed as follows; Co2= 30 mg/L as CaCO3
Ca2+= 180 mg/L as CaCO3
Mg+2= 120 mg/L as CaCO3
Na+= 80 mg/L as CaCO3
Alkalinity = 360 mg/L as CaCO3
SO42- = 10 mg/L as CaCO3
Cl- = 10 mg/L as CaCO3
pH = 7.2
Would softening be recommended for this water? Determine the following quantities (as mg/L of CaCO3): Total hardness, calcium hardness (both carbonate hardness [CH] and non-carbonate hardness[NCH]), and magnesium hardness (both CH and NCH)

Explain the difference laminar and turbulent flow. explain it with the shear stress and the velocity profiles.

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?