Determine the carburizing time necessary to achieve a carbon concentration of 0.20 wt% at a position 4mm into an iron-carbon alloy that initially contains 0.05 wt% C. The surface concentration is to be maintained at 0.90 wt% C, and the treatment is to be conducted at 1000 C. The diffusion pre-exponential for the material D0 is 5.0x10-5 m2/s and the diffusion activation energy Qd is 284,000 J/mol

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature

Prove the equivalence between the two statements of the 2nd law of thermodynamics (i. e., a violation of one statement leads to the violatio the other statement)

Starting wih an energy balance on a rectangular volume element, derive the one- dimensional transient heat conduction equation for a plane wall with constant thermal conductivity and no heat generation.