Nucleation/nucleator

Nucleation Nucleation increases both the mass and number of the granules. For the case where new granules are produced by liquid... 

Primary nucleation (nucleation without crystalline matter)... 

As shown in 4.4.1., two stages usually occur in surface nucleation, nucleation and then nuclei growth. If surface nucleation is fast (Model C) it is likely due to reaction of a gas with the solid particle. The reaction of a liquid is the other possibility, i.e.-... 

Extended chain crystal (ECC) Folded chain crystal (FCC) Growth Growth rate Induction period Melt relaxation Molecular weight Nucleation Nucleation rate Nucleus Optical microscope (OM) Polyethylene Polymer Power law ... 

NUCLEATION. Nucleation creates a new phase that is organizationally more related to the crystal lattice than to the monomeric species that undergoes crystallization. This process permits solutions that are of high relative supersaturation to crystallize and thereby reach equilibrium between liquid and sohd phases . Nucleation occurs when the local concentration of components that will comprise the solid phase exceeds a threshold level as a result of short-range concentration fluctuations in the bulk solution. In this respect, the kinetics of nucle-... 

According to simple solubility considerations, a precipitate will be formed when the product of the concentrations of anions and cations exceeds the solubility product. From another viewpoint, phase transformation occurs when the free energy of the new phase is lower than that of the initial (metastable) phase. However, there are many examples where the ion product exceeds K p, yet no precipitation occurs—the phenomenon of supersaturation. The solubility product also does not provide information on how the particles of the precipitate form—nucleation. Nucleation involves various physical processes, and both thermodynamic and kinetic aspects must be considered. 

Diffusion control, one dimension Diffusion control, two dimensions Diffusion control, three dimensions Phase boundary control, two dimensions Phase boundary control, three dimensions First order (random nucleation) Nucleation and growth, two dimensions Nucleation and growth, three dimensions... 

Instantaneous nucleation -> nucleation, subentry - instantaneous nucleation... 

Precipitation — The formation of a solid in a solution during a chemical reaction or from a solution that has been oversaturated by a compound [i]. See also -> oversaturation, - nucleation, - nucleation and growth kinetics. 

Fig. 6 Notched Impact Strengths (NIS) of the non-nucleated, -nucleated and -nucleated resins investigated in Sect. 3.1.3 a absolute values b relative values, the non-nucleated grade having been taken as reference for each C2-content. The test speed was about 3.8 ms1, the specimens were injection molded...

PP-homopolymer Non- a-Nucleated nucleated /S-Nucleated PP block copolymer Non-nucleated PP random copoylmer Non-nucleated... 

Crystal nucleation rates, expressed as the number of nuclei formed per unit volume per unit time, increase with protein solubility. Higher solubility leads to increased molecular encounters in solution and reduced levels of supersaturation required for spontaneous nucleation. Nucleation rates typically show a high-power dependence on protein supersaturation, and so empirically increase rapidly above a critical value... 

Fillers in these systems affect two types of nucleation nucleation of bubble formation and nucleation of crystallization. Nucleation of bubble formation affects the density of foam. Nucleation of crystallization affects the balance of gas formation and phase transition. The timing of both processes is critical. ... 

We have seen that in homogeneous-homomolecular nucleation, nucleation does not occur unless the vapor phase is supersaturated with respect to the species. When two or more vapor species are present, neither of which is supersaturated, nucleation can still take place... 

We have seen that in homogeneous-homomolecular nucleation, nucleation does not occur unless the vapor phase is supersaturated with respect to the species. When two or more vapor species are present, neither of which is supersaturated, nucleation can still take place as long as the participating vapor species are supersaturated with respect to a liquid solution droplet. Thus heteromolecular nucleation can occur when a mixture of vapors is subsaturated with respect to the pure substances as long as there is supersaturation with respect to a solution of these substances. The theory of homogeneous-heteromolecular nucleation parallels that of homogeneous-homomolecular nucleation extended to include two or more... 

There are two important steps involved. Nuclea-tion is the initial formation of tiny crystallites. As a liquid cools, small volumes tend to take on a stmcture similar to that of crystals, which will ultimately form. This occurs especially at mould edges, on dust particles and so on, which act as sites for nucleation. Nucleating agents can be added deliberately to cause this to happen. The formation of nuclei is suppressed during glass formation. If only one nucleus forms, a single crystal is produced. If many nuclei form, a polycrystaUine soUd results. 

Nucleation Nucleation takes place because supersaturated solutions are... 

Heterogeneous nucleation. Nucleation induced by fin n matter in a supersaturated liquid. Homogeneous nucleation. Spontaneous nucleation caused by siqiersatination only. 

Secondary nucleation. Nucleation of a supersaturated liquid caused directly or indirectly by the presence... 

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