You can access the distribution details by navigating to My Print Books(POD) > Distribution
The book gas expansion tells what gas expansion is. What gas is doing in the engine or turbine.The atoms in the gas expand by centrifugal force which is from release of elastic convolutions in these atoms. Energy is stored in atoms of matter or gas as elastic convolutions when they are released by fire they recoil and shoot out. Proof for this is that energy can be released by physical force as in fire cracker.