For a steel alloy it has been determined that a carburizing heat treatment of 10 h duration at 753°C will raise the carbon concentration to 0.50 wt% at a point 3.3 mm from the surface. Estimate the time necessary to achieve the same concentration at a 5.6 mm position for an identical steel and at a carburizing temperature of 1060°C. Assume that D0 is 3.2 × 10-5 m2/s and Qd is 104 kJ/mol.

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.