Description
In an isomorphic analysis, any form of flow is the advancement of a process per unit of time, expressed in a specific motive unit [MU∙s-1], e.g., ampere for electric flow or current [A≡C∙s-1], watt for heat flow [W≡J∙s-1], and for chemical flow the unit is [mol∙s-1]. The corresponding isomorphic forces are the partial exergy (Gibbs energy) changes per advancement [J∙MU-1], expressed in volt for electric force [V≡J∙C-1], dimensionless for thermal force, and for chemical force the unit is [J∙mol-1], which deserves a specific acronym ([Jol]) comparable to volt. For chemical processes of reaction and diffusion, the advancement is the amount of motive substance [mol]. The concept was originally introduced by De Donder. Central to the concept of advancement is the stoichiometric number, νX, associated with each motive component X (transformant [1]).
In a chemical reaction, r, the motive entity is the stoichiometric amount of reactant, drnX, with stoichiometric number νX. The advancement of the chemical reaction, drξ [mol], is then defined as
drξ = drnX·νX-1
The flow of the chemical reaction, Ir [mol·s-1], is advancement per time,
Ir = drξ·dt-1
Abbreviation: dtrξ
Reference: Gnaiger_1993_Pure Appl Chem
Communicated by Gnaiger E 2018-10-16
Advancement per volume
- In typical liquid phase reactions the volume of the system does not change during the reaction. When oxygen consumption is measured (νO2 = -1 in the chemical reaction), then the volume-specific oxygen flux is the time derivative of the advancement of the reaction per unit volume [1], JV,O2 = drξO2/dt∙V-1 [(mol∙s-1)∙L-1]. The rate of O2 concentration change is dcO2/dt [(mol∙L-1)∙s-1], where concentration is cO2 = nO2/V. There is a difference between (1) JV,O2 [mol∙s-1∙L-1] and (2) rate of concentration change [mol∙L-1∙s-1]. These merge to a single expression only in a closed system. In open systems, internal transformations (catabolic flux, O2 consumption) are distinguished from external flux (such as O2 supply). External fluxes of all substances are zero in closed systems [2].
References
- Gnaiger E (1993) Nonequilibrium thermodynamics of energy transformations. Pure Appl Chem 65:1983-2002. - »Bioblast link«
- MitoEAGLE preprint 2018-10-16(43) Mitochondrial respiratory states and rates: Building blocks of mitochondrial physiology Part 1. - www.mitoeagle.org/index.php/MitoEAGLE_preprint_2018-02-08
MitoPedia concepts: MiP concept, Ergodynamics