Consider a tube for transporting steam that is not centered properly in a cylindrical insulation material (k = 0.73 W/m∙K). The tube diameter is D1 = 20 mm and the insulation diameter is D2 = 40 mm. The distance between the center of the tube and the center of the insulation is z = 5 mm. If the surface of the tube maintains a temperature of 100°C and the outer surface temperature of the insulation is constant at 30°C, determine the rate of heat transfer per unit length of the tube through the insulation.

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?

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa.s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)

What is a monomer? how do they form a ploymer from the view point of chemical bonding?