find the solidification time of the two iron castings when both are poured

(with no superheats) into the sand molds at initial temperature 28°c.

(i) a slab shaped casting of 10 cm thickness, (ii) a sphere of 10 cm in dia. iron: freezing temp: 1540°c; l= 272 kj/kg; density = 7850 kg/m3 sand: c = 1.17 kj/kg-k; k = 0.865 w/mk; density = 1600 kg/m3

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

An engine runs on the ideal diesel cycle. the cycle has a compression ratio of 20 and a cutoff ratio of 2. the highest temperature in the cycle is 1200 k. if the heat into the system is 300 kj/kg of working fluid and using variable specific heats determine the work produced per mass of working fluid

What is creep? what is stress relaxation?