Consider steady-state evaporation of a spherical toluene (A), which is evaporating into a very large volume of still air (B). You may assume that the size of the sphere is relatively large and thus remains constant over the timescale of interest.

a. Starting with a shell balance, show that for a concentrated solute, the expression for yA as a function of r is given by:

YA= 1- (1- YA, sat)^Ro/r

(where Ro = radius of sphere, yAsat = equilibrium saturation mole fraction of toluene in air)

b. Using this expression for YA, show that you can recover the expression we derived for a dilute solution

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Inspection for bearing condition will include: (clo4) a)-color b)-smell c)-size d)-none of the above

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.