Supercooling

(redirected from Supercooled liquid)

supercooling

[¦sü·pər′kül·iŋ]
(thermodynamics)
Cooling of a substance below the temperature at which a change of state would ordinarily take place without such a change of state occurring, for example, the cooling of a liquid below its freezing point without freezing taking place; this results in a metastable state.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Supercooling

 

cooling of matter to temperatures below those of equilibrium phase transition that brings the matter to a new state of aggregation, or another crystalline modification that does not result in a phase transition. A supercooled material is in a state of metastable equilibrium.

The phase transitions that are associated with loss of heat— condensation, crystallization, and polymorphic transformations —usually involve supercooling in their initial stages; the supercooling helps generate nuclei of the new phase in the form of tiny droplets or crystallites. It is difficult to form nuclei at the phase-transition temperature because the nuclei feature higher pressure or solubility and thus cannot be in equilibrium with the initial phase at this temperature. Under conditions where the generation and growth of nuclei of a new phase are inhibited, for example, during recrystallization of a solid and during crystallization of a highly viscous liquid, deep supercooling can be used to obtain a practically stable phase whose internal structure resembles that of phases at higher temperatures. This procedure is the basis for steel-quenching processes and for the production of glass. The degree to which water vapor is supercooled in the atmosphere determines whether precipitation will occur in the form of rain, snow, or hail.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
"Once we achieved amorphous ice, we planned to raise the temperature and pressure and observe the local molecular ordering as the amorphous ice 'melts' into a supercooled liquid and then recrystallizes," Tulk said.
Freezing rain may start off as snow but at some point it passes through different temperatures to become a supercooled liquid.
This graduate text introduces the mechanisms of glass formation related to the stability of the supercooled liquid, particularly the limiting of crystal nucleation and the limiting of their growth in relation to the formation of crystals and quasicrystals, and describes the structural changes that occur in metallic glasses during heating.
Finally, representations of [v.sup.sat.sub.w] (T), [[kappa].sup.sat.sub.T](T), and [p.sub.sat](T) are needed for supercooled liquid water.
NASA Glenn Research Center's Supercooled Liquid Water Content (SLWC) sensor, co-developed by Anasphere Inc., is the only device of its type that supplies access to near-real-time information on icing conditions, with detailed atmospheric profiles that are invaluable to the aircraft industry, meteorologists and researchers.
Rauber and Grant [13] indicated that supercooled liquid water (SLW) layers are common in orographic cloud systems with cloud tops at temperatures as low as -31[degrees]C.
It should be noted that, with Ag addition, the value of ATx has been obviously enlarged; especially, [Ti.sub.41][Zr.sub.25][Be.sub.30][Ag.sub.4] glass alloy has the largest supercooled liquid region of 81K in the Ti-Zr-Be-Ag alloy system.
Cold sodium acetate is an example of a supercooled liquid. That means that the sodium acetate is liquid even when the temperature is lower than its freezing point.
According to the new study by chemists Valeria Molinero and Emily Moore, supercooled liquid water must become ice at minus 55 F not just because of the extreme cold, but because the molecular structure of water changes physically to form tetrahedron shapes, with each water molecule loosely bonded to four others.
The powerful booster technology using supercooled liquid fuel is designed to put heavier satellites into high orbits, about 36,000 km from Earth.