72) The blast furnace gas is a by-product in the production of pig iron in the blast furnace.

73) The heat supplied to the gaS at constant volume is (where m = Mass of gas, c_v = Specific heat at constant volume, c_p = Specific heat at constant pressure, T₂ - T₁ = Rise in temp

74) Liquid fuels have lower efficiency than solid fuels.

75) Liquid fuels consist of hydrocarbons.

76) The dual combustion cycle consists of one constant pressure, two constant volume and two isentropic processes.