In the context of the formation of planets in the solar nebula, the frost line marks the distance from the sun beyond which planets could be cold enough to have snow hydrogen compounds were particularly abundant the temperature was low enough for hydrogen compounds to condense into ices the temperature was low enough for solid rock to condense from the gas.

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)