It is argued that the Carnot cycle is a highly inaccurate representation of a steam engine, and that the net work obtained in its operation would be zero. This conclusion is also supported by an elementary mathematical approach, which reexamines the work done in the four individual steps of the cycle. An important consequence of this is that the concept of entropy, originally proposed on the ba...

We study the efficiency at the maximal power ηmax of a finite-time Carnot cycle of a weakly interacting gas which we can regard as a nearly ideal gas. In several systems interacting with the hot and cold reservoirs of the temperatures Th and Tc, respectively, it is known that ηmax = 1− √ Tc/Th which is often called the Curzon-Ahlborn (CA) efficiency ηCA. For the first time numerical experiments...

The molecular machine in biological systems works as a chemical energy transducer. For instance, the protein motors such as myosin and kinesins, or flagellar motor produce mechanical energy as they consume the chemical energy provided by hydrolysis of ATP or proton density gradient. Some other proteins, such as enzymes or pump proteins of membrane transportation, can be also thought as chemical...

Received: 12 November 2002 / Accepted: 22 May 2003 / Published: 31 December 2003 __________________________________________________________________________________ Abstract: Based on a model of a two-heat-reservoir heat engine with a finite high-temperature source and bypass heat leak, the optimal configuration of the cycle is found for the fixed cycle period with another linear heat transfer l...

From the thermodynamic equilibrium properties of a two-level system with variable energy-level gap ∆, and a careful distinction between the Gibbs relation dE = T dS + (E/∆) d∆ and the energy balance equation dE = δQ← − δW→, we infer some important aspects of the second law of thermodynamics and, contrary to a recent suggestion based on the analysis of an Otto-like thermodynamic cycle between tw...

The efficiency at maximum power output of linear irreversible Carnot-like heat engines is investigated based on the assumption that the rate of irreversible entropy production of the working substance in each "isothermal" process is a quadratic form of the heat exchange rate between the working substance and the reservoir. It is found that the maximum power output corresponds to minimizing the ...

3 TGD based variant of Beauregard’s model and generalization of thermodynamics 3 3.1 Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2 What happens in quantum jump? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.3 Modification of thermodynamics to take into account negentropic entanglement . . . . 4 3.4 The analog of Carnot cy...