Clausius found that this process satisfied the equality of his namesake inequality, i.e. the integral of d Q over T around it is zero. Introduced in On the Motive Power of Fire, this process forms a rectangle in T-S coordinates and is thus fully reversible. Its namesake is also the namesake of a form of the second law of thermodynamics stating that no two-reservoir heat cycle can have efficiency greater than one minus the reservoir absolute temperature ratio; that efficiency is this thermodynamic cycle's efficiency. For 10 points, name this ideal thermodynamic cycle consisting of alternating isothermal and isentropic 
Clausius found that this process satisfied the equality of his namesake inequality, i.e. the integral of d Q over T around it is zero. Introduced in On the Motive Power of Fire, this process forms a rectangle in T-S coordinates and is thus fully reversible. Its namesake is also the namesake of a form of the second law of thermodynamics stating that no two-reservoir heat cycle can have efficiency greater than one minus the reservoir absolute temperature ratio; that efficiency is this thermodynamic cycle's efficiency. For 10 points, name this ideal thermodynamic cycle consisting of alternating isothermal and isentropic or adiabatic steps; a cycle named for a French engineer.
Clausius found that this process satisfied the equality of his namesake inequality, i.e. the integral of d Q over T around it is zero.
the {Carnot} cycle