Nucleation formation

The problem of nucleation (birth of an interface capable of growth) followed by growth is a very common one in chemical engineering. Not only does it arise for nucleate boiling, but also for condensation, crystallization from solutions, and freezing. The rupture of glass subjected to hydrostatic tension is treated as nucleation (formation of first tiny... 

Thin-Film Stage. The mechanism of thin-film formation is characterized by three simultaneous crystal building processes nucleation (formation), growth, and coalescence of three-dimensional crystallites (TDCs). 

We have suggested previously that the formation time of nucleates is much lower than that obtained experimentally. At time t = 0 there exist N0 sites and the probability of nucleate formation per unit time on a single site is v. The formation rate of nucleates at time / is... 

The topochemical model, however, describes the origination and growth of macrostructures. In principle one could construct kinetic models accounting for the kinetics of cluster (or nucleate) formation as a model for the system or reverse consecutive reactions [114, 121]. 

The same applies to a crystallizer, but here it is additionally important that nucleation (formation of new crystals) is controlled, for example by controlled addition of small crystals (seeding) and dissolving nuclei. Crystallization is often very sensitive to levels of impurities, so it is important to use the same materials on a small and on a large scale. 

A way to preserve vegetables vs. time is first to blanch them and afterwards to cool them in order to transform available liquid water into ice. This process is called "freezing" and has been established as an excellent method for preserving high quality in foods (Reid, 1983). Nucleation (formation of ice crystals) and crystal growth are the two major thermal events of the... 

Semiciystalline PS nucleates formation of P-phase in iPP whereas amorphous PS nucleates formation of a-phase in iPP. Isotactic polystyrene nanofibers can be used for P nucleation of iPP." ... 

Mixing is the most essential key factor in the control of nucleation formation and particle growth. 

Heterogeneous ice nucleation Formation of For a dilute solution where volume occupied by solute is negligible In (Pw(Dp)/P°fiat) = (4Afv CT /RTpwDp) /heterogenous = (kT/h)eXp((-AFdij 7 )/ Dependence on contact angle... 

The free energy of germ (nucleation) formation depends on the radius of the crystallites, which is represented in Fig. 7.2. 

For calculation of the transformation temperature Ttrans, thermodynamic equiUbrium in the system is assumed. Delayed transformation due to lack of nucleation formation is disregarded. 

GM Pound, WK La Mer. Kinetics of crystalline nucleation formation in supercooled liquid tin. 74 2323-2332, 1952. 

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