A plant might be emitting some dangerous pollutants that are environmentally harmful, but completely eliminating them would be so expensive that the plant would have to close, throwing many local inhabitants out of work. Assuming there is an obligation both to preserve jobs and to protect the environment. What is the best technique that should be used to resolve this problem? Select one:
a. The convergence and divergence techniques
b. The Utilitarian approach
c. The creative middle way
d. The line drawing technique

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?

Water in a partially filled large tank is to be supplied to the roof top, which is 8 m above the water level in the tank, through a 2.2-cm-internal-diameter pipe by maintaining a constant air pressure of 300 kpa (gage) in the tank. if the head loss in the piping is 2 m of water, determine the discharge rate of the supply of water to the roof top in liters per second.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.