disgregation

Borrowed from Latin disgregātiō, from dis- (“apart”) + grex (“flock”).

The thermodynamics sense was introduced in 1862 by German physicist Rudolf Clausius in his formulation of what is now called the second law of thermodynamics.

disgregation (countable and uncountable, plural disgregations)

1. Separation; scattering.
   • 2006, Raquel Hervás, Pablo Gervás, Agent-Based Solutions for Natural Language Generation Tasks, Roque Marín, Eva Onaindía, Alberto Buarín, José Santos (editors), Current Topics in Artificial Intelligence: 11th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 2005, Springer, LNAI 4177, page 109,

     If the first one is called before the second one, very few disgregations will be performed on the text, since the concepts initially have no associated list of attributes.

   • 2007, Christopher L. Hughes, New Research on Politics and Economics of Europe, Nova Science Publishers, page vii,

     Nevertheless, food processors could obtain gains for conventional products after market disgregation.

   • 2012, Luca Barattoni, Italian Post-Neorealist Cinema, Edinburgh University Press, page 228,

     […] they are granted a privileged point of view in the disgregation of subjectivity in Antonioni; and after La dolce vita they become a prismatic aggregate of male neuroses in Fellini, like a parade of everted obsessions put on display.

2. (thermodynamics, obsolete or historical) A measure of the separation of the particles of a system; an early formulation of entropy.
   • 1868, R. Clausius, On the Second Fundamental Theorem of the Mechanical Theory of Heat, [1867, Lecture to the German Scientific Association], The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, page 408,

     The disgregation of a body is consequently, among the three states of aggregation, least in the solid state, greater in the liquid state, and greatest of all in the gaseous state. In the last condition it can still be increased by the molecules separating further from each other—that is, by the gas expanding to a larger volume. In like manner, the decomposition of a chemically compound body into its elements is in general accompanied by an increase of disgregation.

     By help of this conception the effect of heat can be simply expressed by saying that heat tends to increase the disgregation of bodies.

   • 1880, Robert Röntgen, The Principles of Thermodynamics: With Special Applications to Hot-air, Gas and Steam Engines, J. Wiley, page 95,

     The gas, however, may experience the same changes of volume and disgregation in another manner.

   • 2016, Kerry Kuehn, A Student's Guide Through the Great Physics Texts, Volume IV: Heat, Atoms and Quanta, Springer, page 84,

     Since the increase of disgregation is the action by means of which heat performs work, it follows that the quantity of work must bear a definite ratio to the quantity by which the disgregation is increased; we will therefore fix the still arbitrary determination of the magnitude of disgregation so that, at any given temperature, the increase of disgregation shall be proportional to the work which the heat can thereby perform.

• (separation): aggregation, congregation

• History of entropy on Wikipedia.Wikipedia