An FCC iron-carbon alloy initially containing 0.20 wt% C is carburized at 1400K and in an atmosphere that gives a surface carbon concentration constant at 1.0 wt%. After how many hours does the concentration of carbon reach at 0.35 wt% at a position 5.0 mm below the surface?

Steam enters a converging nozzle at 3.0 mpa and 500°c with a at 1.8 mpa. for a nozzle exit area of 32 cm2, determine the exit velocity, mass flow rate, and exit mach number if the nozzle: negligible velocity, and it exits (a) is isentropic (b) has an efficiency of 94 percent