Liquid octane (c8h18) at 25°c, 1 atm enters an insulated reactor operating at steady state and burns completely with air entering at 227°c, 1 atm. the combustion products exit the reactor at 1127°c. determine the percent excess air used. neglect kinetic and potential energy effects.

Abritle material made of astm grade 30 cast iron has ultimate strength in tension of 31 kpsi and altimate strength in compression of 109 kpsi and undergoes the following plane of stress te 20 lepst and ry10 kpsi (cw). a) using the 3d mohr's circle, find all three principal normal stresses. b) using the brittle-coulomb-mohr theory and modified-mohr theory. ind the factors of safety for the given plane of stress state.