Entropy production

Entropy production quantifies the irreversible generation of entropy within a process. It is nonnegative for processes in isolated systems and vanishes for reversible processes.

Second law of thermodynamics: A physical law stating that the entropy of an isolated system never decreases. Its inequality requires nonnegative entropy production in isolated processes.
Thermodynamic entropy: A state function measuring energy dispersal and the number of microscopic states compatible with a macroscopic condition. Production describes entropy created during a process, not entropy as a state property.
Viscous dissipation: Conversion of mechanical energy into internal energy by viscous stresses in a flowing fluid. Viscous stress and velocity gradients create entropy within fluid flows.
Entropy transfer: The movement of entropy into or out of a system through heat or matter crossing its boundary. Transfer changes a system's entropy without being entropy produced inside it.
Exergy: The maximum useful work obtainable as a system comes into equilibrium with its environment. Entropy production destroys exergy, reducing the work a system can deliver.
Entropy balance: An accounting equation separating entropy change into transfer across a boundary and production within a system. It distinguishes internally produced entropy from entropy carried by heat or matter.
Reversible process: An idealized process that can be reversed without leaving any net change in the system and surroundings. Its entropy production is zero, unlike that of an irreversible process.
Joule heating: Heating caused when electric current dissipates energy through a material's electrical resistance. Electrical resistance converts work into heat and produces entropy.
Open system: A system that exchanges both matter and energy with its surroundings. Its entropy can decrease through export even while its internal production remains nonnegative.
Thermodynamic irreversibility: The inability of a real process to be reversed without producing changes in the system or surroundings. Entropy production provides a quantitative measure of this loss of reversibility.

Linked from 11 pages