Simple correction to the classical theory of homogeneous nucleation

2005 ◽  
Vol 122 (10) ◽  
pp. 104511 ◽  
Author(s):  
Alexey B. Nadykto ◽  
Fangqun Yu
Keyword(s):  
Classical Theory ◽  
Homogeneous Nucleation

Transient Nucleation in Devitrification

1993 ◽  
Vol 321 ◽  
Author(s):  
A. L. Greer
Keyword(s):  
Classical Theory ◽  
Heterogeneous Nucleation ◽  
Glass Formation ◽  
Homogeneous Nucleation ◽  
Amorphous Solids ◽  
Crystal Nucleation ◽  
Transient Effects ◽  
Interphase Interface ◽  
Transient Nucleation ◽  
Important Test

ABSTRACTA review is given of transient crystal nucleation in glassy or amorphous solids. The types of behaviour are surveyed. It is shown that the kinetics can be quantitatively modelled and that the matching of experiment and theory provides an important test of the classical theory. Examples are considered of homogeneous nucleation (affecting glass formation), heterogeneous nucleation, and nucleation at an interphase interface. While the emphasis is on transient effects of the kind implicit in the classical theory, it is shown that transients can arise for other reasons as well, thus potentially complicating the interpretation of experiments.

Condensation of supersaturated vapours. Homogeneous nucleation of naphthalene and phthalic anhydride

1985 ◽  
Vol 50 (6) ◽  
pp. 1349-1358 ◽  
Author(s):  
Jiří Smolík ◽  
Jaroslav Vítovec
Keyword(s):  
Surface Tension ◽  
Thermal Diffusion ◽  
Classical Theory ◽  
Phthalic Anhydride ◽  
Homogeneous Nucleation ◽  
Corresponding States ◽  
Experimental Results ◽  
Critical Supersaturation ◽  
Fluid Behaviour ◽  
Good Agreement

The critical supersaturation required for the homogeneous nucleation of naphthalene and phthalic anhydride from their vapours has been measured using upward thermal diffusion cloud chamber. The results obtained are compared with the predictions of the classical theory of homogeneous nucleation (Volmer-Becker-Doring-Zeldovich) and the corresponding states correlation of homogeneous nucleation. The classical theory is found to be in excellent agreement with the experimental results on naphthalene but overpredicts the critical supersaturation of phthalic anhydride vapours by about 30%. In order to fit the experiment and theory, the new values of surface tension of phthalic anhydride were recalculated from the theory. Critical supersaturation of naphthalene plotted versus temperature reveals the same regular departure from single fluid behaviour as found for alkylbenzenes. The experimental results on phthalic anhydride were found to be in very good agreement with the corresponding states correlation.

scholarly journals Homogeneous Nucleation of Hydroxyapatite, Ca5OH(PO4)3, at 37 °C

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 695 ◽  
Author(s):  
Hans Erik Lundager Madsen
Keyword(s):  
Free Energy ◽  
Light Scattering ◽  
Calcium Phosphate ◽  
Surface Free Energy ◽  
Classical Theory ◽  
Homogeneous Nucleation ◽  
Crystal Surface ◽  
Small Particles ◽  
Large Particles

Precipitation of the calcium phosphate hydroxyapatite, Ca5OH(PO4)3, is studied by simple mixing of reagent solutions and measurement of light scattering (turbidimetry) at six different wavelengths from 300 to 800 nm. Measured turbidities are analyzed using Mie’s theory of light scattering from small particles. Results are interpreted in terms of classical theory of homogeneous nucleation, and from this the surface free energy of crystals is determined. The low value thus found is explained as the effect of protonation of the strongly basic anions hydroxide and phosphate at the crystal surface. Relatively large particles registered by turbidimetry are shown to be not monocrystals, but aggregates of nanocrystals.

Homogeneous Vapor Nucleation and Superheat Limits of Liquid Mixtures

1979 ◽  
Vol 101 (4) ◽  
pp. 617-621 ◽  
Author(s):  
E. L. Pinnes ◽  
W. K. Mueller
Keyword(s):  
Equation Of State ◽  
General Theory ◽  
Vapor Phase ◽  
Classical Theory ◽  
Homogeneous Nucleation ◽  
Liquid Mixtures ◽  
The Other ◽  
Hydrocarbon Mixtures ◽  
Vapor Nucleation ◽  
Component Case

Two features distinguish vapor nucleation in multicomponent liquids from the single component case. Both result from the unequal volatilities of the species. One is that the vapor phase may contain several components; the other is that nucleus formation alters the composition of the nearby liquid. These two features are incorporated into the classical theory of homogeneous nucleation to yield a general theory applicable to multicomponent liquids. The theory is applied to binary hydrocarbon mixtures by using an equation of state extrapolated into the metastable region. Superheat limits thus calculated are compared with published experimental results.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Lattice imaging of precipitates in Al-Zn-Mg alloy

1986 ◽  
Vol 44 ◽  
pp. 412-413
Author(s):  
C. K. Wu
Keyword(s):  
Grain Boundaries ◽  
Homogeneous Nucleation ◽  
Alloy System ◽  
Mg Alloy ◽  
List Type ◽  
Lattice Structures ◽  
Type Number ◽  
Orientation Relationships ◽  
Lattice Imaging ◽  
The Matrix

The precipitation phenomenon in Al-Zn-Mg alloy is quite interesting and complicated and can be described in the following categories:(i) heterogeneous nucleation at grain boundaries;(ii) precipitate-free-zones (PFZ) adjacent to the grain boundaries;(iii) homogeneous nucleation of snherical G.P. zones, n' and n phases inside the grains. The spherical G.P. zones are coherent with the matrix, whereas the n' and n phases are incoherent. It is noticed that n' and n phases exhibit plate-like morpholoay with several orientation relationship with the matrix. The high resolution lattice imaging techninue of TEM is then applied to study precipitates in this alloy system. It reveals the characteristics of lattice structures of each phase and the orientation relationships with the matrix.

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