1. (a) Can you define the term "adiabatic flame temperature"? (5%) (b) What is the reason for the highest adiabatic flame temperature of many hydrocarbon fuels being observed in fucl-rich conditions? (5%) (c) Define the term "unstretched laminar burning velocity" in the context of hydrocarbon fuels. (5%) (d) Could you describe the experimental process for measuring the unstretched laminar burning velocity of methane/air, including the necessary apparatus and measurement procedures? (5%)