Afreezer compartment consists of a cubical cavity that is 2 m on a side. assume the bottom to be perfectly ulated (no heat flow). what is the minimum thickness of styrofoam insulation (k = 0.030 w/m/k) that must be applied to the top and side walls to ensure a heat load of less than 500 w, when the inner and outer surfaces are at -10 and 35c? (so the walls are made of styrofoam only)

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)