2. (a) Explain why steel is ductile at room temperature, but may be brittle at a low temperature. (b) A number of treatments can affect the yield strength of the steel, e. g., work hardening, tempering (modifying the precipitates), grain growth (changing the grain size), etc. To minimize the brittle-to-ductile transition temperature (TBD), should we try to increase or decrease the yield strength

Asteam is contained in a rigid tank with a volume of 1 m3. initially, the pressure and temperature are 7 bar and 500 oc, respectively. the temperature drops due to cooling process. determine: (1) the temperature at which condensation begins in °c, (2) the fraction of the total mass that has condensed when the pressure decreased to 0.5 bar. (3) the volume in m3 occupied by saturated liquid at the final state?