NUCLEATION MECHANISM 1)2)
A mechanism by which a new structure establishes itself first in a limited region and than invades the whole space.
According to G. NICOLIS and I. PRIGOGINE, the concept originates in physico-chemistry as"… the phenomenon of nucleation familiar from equilibrium phase transitions" (1977, p.323).
It appears when a system submitted to widening fluctuations becomes unstable, which leads to dissipative structuration. The new structure will be a more or less randomly result of the antagonism between the instability that tends to amplify the fluctuation and "the effect of the large outside environment in which fluctuations may be neglected. The outside world thus acts as a mean field that tends to damp the fluctuations through the interactions which occur on the boundaries of the fluctuating region… In the case of small size fluctuations, boundary effects will dominate and fluctuations will regress. On the contrary, for large scale fluctuations, boundary effects become negligible.
Between these limiting cases lies the actual size of nucleation. This is the reason why a general law of fluctuations independent of size, such as given by a POISSON distribution, is no longer valid" (PRIGOGINE et al., 1978, p.52).
The same mechanism is obviously present in population genetics and in technical innovation, for instance. P.P. GRASSÉ's stigmergy also is an example of a nucleation mechanism.
- 1) General information
- 2) Methodology or model
- 3) Epistemology, ontology and semantics
- 4) Human sciences
- 5) Discipline oriented
To cite this page, please use the following information:
Bertalanffy Center for the Study of Systems Science (2020). Title of the entry. In Charles François (Ed.), International Encyclopedia of Systems and Cybernetics (2). Retrieved from www.systemspedia.org/[full/url]
We thank the following partners for making the open access of this volume possible: