Journal articles: 'Nucleation and Crystal Growth'

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Adnan, Siti Zubaidah, and Noor Asma Fazli Abdul Samad. "Effects of Nucleation and Crystal Growth Rates on Crystal Size Distribution for Seeded Batch Potash Alum Crystallization Process." ASEAN Journal of Chemical Engineering 22, no. 2 (December 29, 2022): 258. http://dx.doi.org/10.22146/ajche.74121.

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The driving force of the cooling crystallization process is supersaturation, where the supersaturation level during the crystallization process is crucial to grow the crystal sufficiently. Nucleation and crystal growth rates are two concurrent phenomena occurring during crystallization. Both are supersaturation functions that determine the growth of seed crystals and the formation of fine crystals. Trade-offs between nucleation and crystal growth are essential for achieving the large size of seed crystals with the minimum number of fine crystals. Thus, the objective of this study is to analyze the effects of nucleation and crystal growth rates on final product quality, which is crystal size distribution (CSD). Modeling of the crystallization process using a potash alum case study is highlighted and simulated using Matlab software. Then, the effects of nucleation rate, crystal growth rate, and both nucleation and crystal growth rates on CSD are evaluated using local sensitivity analysis based on the one-factor-at-a-time (OFAT) method. Based on simulation results for all strategies, a low combined rate delivers the best performance of the final CSD compared to others. Its primary peak has a mean crystal size of 455 µm with 0.0078 m3/m volume distribution. This means that the grown seed crystals are large with high volume distribution compared to the nominal strategy, which is at the mean crystal size of 415 µm and 0.00434 m3/m. Meanwhile, the secondary peak has the mean crystal size of 65 µm, 0.00028 m3/m in volume distribution. This corroborates the least number of fine crystals at the considerably small size compared to nominal’s (0.00151 m3/m, 35 µm). Overall, the low nucleation and crystal growth rates strategy provides useful insights into designing temperature profiles during the linear cooling crystallization process, whereby achievable supersaturation levels in obtaining large crystals with fewer crystal fines are provided via simulation.

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Nanev, Christo N., Emmanuel Saridakis, Lata Govada, and Naomi E. Chayen. "Protein Crystals Nucleated and Grown by Means of Porous Materials Display Improved X-ray Diffraction Quality." International Journal of Molecular Sciences 23, no. 18 (September 14, 2022): 10676. http://dx.doi.org/10.3390/ijms231810676.

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Well-diffracting protein crystals are indispensable for X-ray diffraction analysis, which is still the most powerful method for structure-function studies of biomolecules. A promising approach to growing such crystals is the use of porous nucleation-inducing materials. However, while protein crystal nucleation in pores has been thoroughly considered, little attention has been paid to the subsequent growth of crystals. Although the nucleation stage is decisive, it is the subsequent growth of crystals outside the pore that determines their diffraction quality. The molecular-scale mechanism of growth of protein crystals in and outside pores is theoretically considered. Due to the low degree of metastability, the crystals that emerge from the pores grow slowly, which is a prerequisite for better diffraction. This expectation has been corroborated by experiments carried out with several types of porous material, such as bioglass (“Naomi’s Nucleant”), buckypaper, porous gold and porous silicon. Protein crystals grown with the aid of bioglass and buckypaper yield significantly better diffraction quality compared with crystals grown conventionally. In all cases, visually superior crystals are usually obtained. Our theoretical conclusion is that heterogeneous nucleation of a crystal outside the pore is an exceptional case. Rather, the protein crystals nucleating inside the pores continue growing outside them.

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Parrinello, Michele. "Atomistic Modeling of Crystal Nucleation and Growth." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C39. http://dx.doi.org/10.1107/s2053273314099604.

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Understanding crystal growth from solution is crucial to control the development of crystal morphologies. Since the interaction of crystals with their environment occurs through their surface, their shape controls a wide variety of properties. This is particularly important not only in nanotechnology, where shape-function relations play a key role, but also in medicine where, e.g., changing the morphology of particles allows for a better targeting of cancer cells. In this work we combine experiments, molecular simulations and theory to examine the morphology of urea crystals grown in different solutions. In order to get a rational representation of all the possible habits we introduce a Shape Diagram in which the habit dependence on the relative growth rates is displayed. A wide portion of the habit space can be experimentally explored by varying the composition of the mother solution. By doing so we obtain morphologies ranging from the paradigmatic needle-like habit obtained in water to regular tetrahedra obtained in acetonitrile/biuret mixtures. By combining advanced molecular simulation techniques and theory we can predict urea steady state crystal habits and their dependence on additive concentration and/or supersaturation, paving the way towards a rational control of the habit of crystals grown from solution. We present also some other example of nucleation processes which will lead to some rather surprising results even in the case of humble NaCl. Finally we discuss some recent advances that allow us to calculate nucleation rates.

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Pervov, Alexei. "Investigation of Scaling and Inhibition Mechanisms in Reverse Osmosis Spiral Wound Elements." Membranes 12, no. 9 (August 31, 2022): 852. http://dx.doi.org/10.3390/membranes12090852.

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Understanding of crystal formation and growth conditions in reverse osmosis membrane channels enables us to develop efficient tools to control scaling in membrane facilities and increase their recoveries. Crystals are formed in “dead areas” and subsequently get out of them and sediment on membrane surface. Adsorption of polymeric inhibitor molecules to crystal surface was investigated as well as antiscalant behaviour throughout nucleation in “dead areas” and growth of crystals sedimented on membrane surface. Experimental dependencies of antiscalant adsorption rates on the antiscalant dosage values were determined. Examination of SEM images of crystals demonstrated that their size and amount depend on the supersaturation value reached in the “dead areas”. More efficient antiscalants delay the beginning of nucleation and reduce the rate of crystal growth due to adsorption and blockage of crystal growth process. Antiscaling property of inhibitors is also attributed to their ability to provide certain amount of adsorbent to block crystal growth during nucleation. A test procedure is described that enables us to predict concentrate composition in the “dead areas” and calculate supersaturation values that correspond to beginning of nucleation.

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Gui, Yue, Chengbin Huang, Chenyang Shi, Torsten Stelzer, Geoff G. Z. Zhang, and Lian Yu. "Polymorphic selectivity in crystal nucleation." Journal of Chemical Physics 156, no. 14 (April 14, 2022): 144504. http://dx.doi.org/10.1063/5.0086308.

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Crystal nucleation rates have been measured in the supercooled melts of two richly polymorphic glass-forming liquids: ROY and nifedipine (NIF). ROY or 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile is known for its crystals of red, orange, and yellow colors and many polymorphs of solved structures (12). Of the many polymorphs, ON (orange needles) nucleates the fastest with the runner up (Y04) trailing by a factor of 103 when compared under the same mobility-limited condition, while the other unobserved polymorphs are slower yet by at least 5 orders of magnitude. Similarly, of the six polymorphs of NIF, [Formula: see text]′ nucleates the fastest, [Formula: see text]′ is slower by a factor of 10, and the rest are slower yet by at least 5 decades. In both systems, the faster-nucleating polymorphs are not built from the lowest-energy conformers, while they tend to have higher energies and lower densities and thus greater similarity to the liquid phase by these measures. The temperature ranges of this study covered the glass transition temperature Tg of each system, and we find no evidence that the nucleation rate is sensitive to the passage of Tg. At the lowest temperatures investigated, the rates of nucleation and growth are proportional to each other, indicating that a similar kinetic barrier controls both processes. The classical nucleation theory provides an accurate description of the observed nucleation rates if the crystal growth rate is used to describe the kinetic barrier for nucleation. The quantitative rates of both nucleation and growth for the competing polymorphs enable prediction of the overall rate of crystallization and its polymorphic outcome.

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Zhou, Wuzong. "Reversed Crystal Growth." Crystals 9, no. 1 (December 22, 2018): 7. http://dx.doi.org/10.3390/cryst9010007.

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In the last decade, a reversed growth route has been found in many crystal growth processes. In these systems, a single crystal does not develop from a single nucleus. The precursor molecules/ions or nanocrystallites aggregate into some large amorphous or polycrystalline particles. Multiple-nucleation on the surface of the amorphous particles or surface re-crystallization of the polycrystalline particles then takes place, forming a single crystal shell with a regular morphology. Finally, the crystallization extends from the surface to the core to form single crystals. This non-classical crystal growth route often results in some special morphologies, such as core-shell structures, hollow single crystals, sandwich structures, etc. This article gives a brief review of the research into reversed crystal growth and demonstrates that investigation of detailed mechanisms of crystal growth enables us to better understand the formation of many novel morphologies of the crystals. Some unsolved problems are also discussed.

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Quattrosoldi, Silvia, René Androsch, Andreas Janke, Michelina Soccio, and Nadia Lotti. "Enthalpy Relaxation, Crystal Nucleation and Crystal Growth of Biobased Poly(butylene Isophthalate)." Polymers 12, no. 1 (January 18, 2020): 235. http://dx.doi.org/10.3390/polym12010235.

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The crystallization behavior of fully biobased poly(butylene isophthalate) (PBI) has been investigated using calorimetric and microscopic techniques. PBI is an extremely slow crystallizing polymer that leads, after melt-crystallization, to the formation of lamellar crystals and rather large spherulites, due to the low nuclei density. Based upon quantitative analysis of the crystal-nucleation behavior at low temperatures near the glass transition, using Tammann’s two-stage nuclei development method, a nucleation pathway for an acceleration of the crystallization process and for tailoring the semicrystalline morphology is provided. Low-temperature annealing close to the glass transition temperature (Tg) leads to the formation of crystal nuclei, which grow to crystals at higher temperatures, and yield a much finer spherulitic superstructure, as obtained after direct melt-crystallization. Similarly to other slowly crystallizing polymers like poly(ethylene terephthalate) or poly(l-lactic acid), low-temperature crystal-nuclei formation at a timescale of hours/days is still too slow to allow non-spherulitic crystallization. The interplay between glass relaxation and crystal nucleation at temperatures slightly below Tg is discussed.

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Liu, Yao, Huilin He, and Yanjun Liu. "Morphology control of laser-induced dandelion-like crystals of sodium acetate through the addition of acidic polymers." Journal of Applied Crystallography 54, no. 4 (July 7, 2021): 1111–20. http://dx.doi.org/10.1107/s1600576721005409.

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Crystal growth speeds, crystal sizes and the morphology of sodium acetate (CH3COONa) crystals in the presence of polymaleic acid and polyacrylic acid with different concentrations were investigated in supersaturated solutions of sodium acetate. The technique of non-photochemical laser-induced nucleation (NPLIN) was used to produce initial crystallites of anhydrous CH3COONa. The anhydrous CH3COONa crystal growth in solution after laser irradiation resembled the formation of dandelion seed heads. Even though NPLIN could offer temporal–spatial control of crystal nucleation without the addition of acidic polymers, the crystal growth rates were heterogeneous for crystallites along the laser pathway, which led to irregular crystalline sizes and morphologies. Here, a controllable approach from crystal nucleation to crystal growth has been designed through the addition of acidic polymers in the laser-induced growth of anhydrous CH3COONa crystals. In the presence of an acidic polymer, both the crystal growth and the morphological modification were controlled from tuft-shaped crystals to dandelion-like crystals. As bulk solid thicknesses and crystal growth speeds can be modified by different mass fractions of acidic polymer, a mathematical model was established to analyse the dynamics of crystal growth under the effect of acidic polymers. The model reproduces remarkably well the experimental trend and predicts experimental results. The changes in supersaturation and the number of nuclei through the addition of acidic polymers were analysed to investigate the underlying mechanism of morphological difference.

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Mehrotra, B. N. "Crystal growth by metastable nucleation." Acta Crystallographica Section A Foundations of Crystallography 43, a1 (August 12, 1987): C119. http://dx.doi.org/10.1107/s0108767387082291.

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Brown, Dennis J., Keith R. Cliffe, and Ian M. Grimsey. "Sucrose crystal nucleation and growth." Analytical Proceedings 30, no. 11 (1993): 458. http://dx.doi.org/10.1039/ap9933000458.

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Ong, T. P., Fulin Xiong, R. P. H. Chang, and C. W. White. "Nucleation and growth of diamond on carbon-implanted single crystal copper surfaces." Journal of Materials Research 7, no. 9 (September 1992): 2429–39. http://dx.doi.org/10.1557/jmr.1992.2429.

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The nucleation and growth of diamond crystals on single crystal copper surfaces has been studied. Microwave plasma enhanced chemical vapor deposition (MPECVD) was used for diamond nucleation and growth. Prior to diamond nucleation, the single crystal copper surface is modified by carbon ion implantation at an elevated temperature (∊820 °C). This procedure leads to the formation of a graphite film on the copper surface, resulting in an enhancement of diamond crystallite nucleation. A simple lattice model has been constructed to describe the mechanism of diamond nucleation on graphite as 〈111〉diamond parallel to 〈0001〉graphite and 〈110〉diamond parallel to 〈11$\overline 1$0〉graphite. This leads to a good understanding of diamond growth on carbon-implanted copper surfaces.

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Manikandan, M. R., S. D. Gopal Ram, and G. Ravi. "Growth of Optical Quality 4-Dimethylamino-N-Methyl-4-Stilbazolium Tosylate (DAST) Single Crystals by Novel Technique and their Characterization." Advanced Materials Research 584 (October 2012): 42–46. http://dx.doi.org/10.4028/www.scientific.net/amr.584.42.

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Optical quality 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystals have been grown by a novel technique. In conventional growth methods, it was difficult to control the position of spontaneous nucleation, number of nuclei, cluster formation and the nucleation period. Difficulty in the nucleation and growth positioning was effectively solved by the slope nucleation method (SNM) and sizable DAST crystal was grown by two zone growth technique (TZGT) using a seed. Furthermore removal and fixing of seed crystal was difficult in the two zone growth technique. In the present study, we could obtain optical quality bulk DAST crystals by combining SNM and TZGT. The growth rates, size are estimated with respect to temperature gradient and slope shape. The structural, functional and optical analyses were carried for the grown crystals and the results are discussed in detail.

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Warzecha, Monika, Alastair J. Florence, and Peter G. Vekilov. "The Ambiguous Functions of the Precursors That Enable Nonclassical Modes of Olanzapine Nucleation and Growth." Crystals 11, no. 7 (June 26, 2021): 738. http://dx.doi.org/10.3390/cryst11070738.

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One of the most consequential assumptions of the classical theories of crystal nucleation and growth is the Szilard postulate, which states that molecules from a supersaturated phase join a nucleus or a growing crystal individually. In the last 20 years, observations in complex biological, geological, and engineered environments have brought to light violations of the Szilard rule, whereby molecules assemble into ordered or disordered precursors that then host and promote nucleation or contribute to fast crystal growth. Nonclassical crystallization has risen to a default mode presumed to operate in the majority of the inspected crystallizing systems. In some cases, the existence of precursors in the growth media is admitted as proof for their role in nucleation and growth. With the example of olanzapine, a marketed drug for schizophrenia and bipolar disorder, we demonstrate that molecular assemblies in the solution selectively participate in crystal nucleation and growth. In aqueous and organic solutions, olanzapine assembles into both mesoscopic solute-rich clusters and dimers. The clusters facilitate nucleation of crystals and crystal form transformations. During growth, however, the clusters land on the crystal surface and transform into defects, but do not support step growth. The dimers are present at low concentrations in the supersaturated solution, yet the crystals grow by the association of dimers, and not of the majority monomers. The observations with olanzapine emphasize that detailed studies of the crystal and solution structures and the dynamics of molecular association may empower classical and nonclassical models that advance the understanding of natural crystallization, and support the design and manufacture of promising functional materials.

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Gao, Yang, Baohua Guo, and Jun Xu. "Critical Size of Secondary Nuclei Determined via Nucleation Theorem Reveals Selective Nucleation in Three-Component Co-Crystals." Entropy 21, no. 11 (October 24, 2019): 1032. http://dx.doi.org/10.3390/e21111032.

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The critical size of the secondary nuclei plays an important role in determining the crystal growth rate. In the past, the Nucleation Theorem has been applied to determine the number of molecules in the critical nuclei of a single-component crystal via variation of the crystal growth rate with dilution by the non-crystallizable component. In this work, we extend the method to the three-component co-crystal poly (ethylene oxide)/urea/thiourea inclusion compound. The theoretical crystal growth kinetics were deduced and the dependence of the radial growth rate of the inclusion compound spherulites on the mass fraction of urea in urea/thiourea was measured. The results reveal that the secondary nuclei of the poly (ethylene oxide)/urea/thiourea inclusion compound consist mainly of ethylene oxide repeating units and urea molecules. We propose that only urea molecules and ethylene oxide repeating units are selected to form the secondary nuclei while co-crystallization of the three components happens at the lateral spreading stage. As a result, the composition of the critical secondary nuclei is different from that of the bulk inclusion compound crystals. The work is expected to deepen our understanding of the nucleation of multi-component co-crystals.

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Nanev, Christo. "Peculiarities of Protein Crystal Nucleation and Growth." Crystals 8, no. 11 (November 8, 2018): 422. http://dx.doi.org/10.3390/cryst8110422.

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This paper reviews investigations on protein crystallization. It aims to present a comprehensive rather than complete account of recent studies and efforts to elucidate the most intimate mechanisms of protein crystal nucleation. It is emphasized that both physical and biochemical factors are at play during this process. Recently-discovered molecular scale pathways for protein crystal nucleation are considered first. The bond selection during protein crystal lattice formation, which is a typical biochemically-conditioned peculiarity of the crystallization process, is revisited. Novel approaches allow us to quantitatively describe some protein crystallization cases. Additional light is shed on the protein crystal nucleation in pores and crevices by employing the so-called EBDE method (equilibration between crystal bond and destructive energies). Also, protein crystal nucleation in solution flow is considered.

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Gomery, Kathryn, Elaine C. Humphrey, and Rodney Herring. "Examining Protein Crystallization Using Scanning Electron Microscopy." Microscopy and Microanalysis 19, no. 1 (November 30, 2012): 145–49. http://dx.doi.org/10.1017/s1431927612013293.

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AbstractElucidation of protein structure using X-ray crystallography relies on the quality of the crystal. Crystals suffer from many different types of disorder, some of which occur during crystal nucleation and early crystal growth. To date, there are few studies surrounding the quality and nucleation of protein crystals partly due to difficulties surrounding viewing biological samples at high resolution. Recent research has led our current understanding of nucleation to be a two-step mechanism involving the formation of nuclei from dense liquid clusters; it is still unclear whether nuclei first start as amorphous aggregate or as crystalline lattices. Our research examines this mechanism through the use of electron microscopy. Using scanning electron microscopy imaging of the protein crystal growth process, a stacking, spiraling manner of growth is observed. The tops of the pyramid-like tetragonal protein crystal structures measure ~0.2 μm across and contain ~125,000 lysozyme units. This noncrystalline area experiences strain due to growth of the protein crystal. Our work shows that it is possible to view detailed early stage protein crystal growth using a wet scanning electron microscopy technique, thereby overcoming the problem of viewing liquids in a vacuum.

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Bodier-Houllé, Patricia, Pierre Steuer, Jean-Claude Voegel, and Frédéric J. G. Cuisinier. "First Experimental Evidence for Human Dentine Crystal Formation Involving Conversion of Octacalcium Phosphate to Hydroxyapatite." Acta Crystallographica Section D Biological Crystallography 54, no. 6 (November 1, 1998): 1377–81. http://dx.doi.org/10.1107/s0907444998005769.

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Biological apatite-crystal formation is a complex process starting with heterogeneous nucleation of inorganic calcium phosphate on an organic extracellular matrix [Cuisinier et al. (1995), J. Cryst. Growth, 156, 443–453]. Further stages of crystal growth are also controlled by the organic matrix and both nucleation and growth processes are under cellular control [Mann (1993), Nature (London), 367, 499–505]. The final mineral in calcified tissue is constituted by poorly crystalline hydroxyapatite (HA) with a low Ca:P ratio, containing foreign ions such as carbonate and fluoride. This study reports the first observation of octacalcium phosphate (OCP) [Brown (1962), Nature (London), 196, 1048–1055] in a biological tissue; OCP was found in the central part and HA at the extremities of the same crystal of calcifying dentine. This observation is of key importance in understanding the first nucleation steps of biological mineralization. The presence of OCP in a forming human dentine crystal and the observation in the same tissue of nanometer-sized particles with a HA structure [Houllé et al. (1997), J. Dent Res. 76, 895–904] clearly proves that two mechanisms, direct nucleation of non-stoichiometric HA crystals and nucleation of OCP, occur simultaneously in same area of mineralization. OCP is found to be a transient phase during the growth of biological crystals. In small crystals, OCP is completely transformed into HA by a hydrolysis reaction (Brown, 1962) and can only be detected in larger crystals because of its slow kinetics of transformation.

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Rees Jones, David W., and Andrew J. Wells. "Frazil-ice growth rate and dynamics in mixed layers and sub-ice-shelf plumes." Cryosphere 12, no. 1 (January 8, 2018): 25–38. http://dx.doi.org/10.5194/tc-12-25-2018.

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Abstract. The growth of frazil or granular ice is an important mode of ice formation in the cryosphere. Recent advances have improved our understanding of the microphysical processes that control the rate of ice-crystal growth when water is cooled beneath its freezing temperature. These advances suggest that crystals grow much faster than previously thought. In this paper, we consider models of a population of ice crystals with different sizes to provide insight into the treatment of frazil ice in large-scale models. We consider the role of crystal growth alongside the other physical processes that determine the dynamics of frazil ice. We apply our model to a simple mixed layer (such as at the surface of the ocean) and to a buoyant plume under a floating ice shelf. We provide numerical calculations and scaling arguments to predict the occurrence of frazil-ice explosions, which we show are controlled by crystal growth, nucleation, and gravitational removal. Faster crystal growth, higher secondary nucleation, and slower gravitational removal make frazil-ice explosions more likely. We identify steady-state crystal size distributions, which are largely insensitive to crystal growth rate but are affected by the relative importance of secondary nucleation to gravitational removal. Finally, we show that the fate of plumes underneath ice shelves is dramatically affected by frazil-ice dynamics. Differences in the parameterization of crystal growth and nucleation give rise to radically different predictions of basal accretion and plume dynamics, and can even impact whether a plume reaches the end of the ice shelf or intrudes at depth.

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Knight, F. B., and J. L. Steichen. "An interference problem with application to crystal growth." Advances in Applied Probability 36, no. 3 (September 2004): 725–46. http://dx.doi.org/10.1239/aap/1093962231.

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We model diffusion-controlled crystal growth as an interference problem. The crystal layers grow by nucleation (initiation of crystallization centers) followed by attachment of molecules to the nucleus. A forming crystal layer completes by either spreading across the length of the crystal or by colliding with another spreading crystal layer. This model differs from the classical Johnson-Mehl-Kolmogorov model in that nucleation happens only on boundaries of a ‘seed’ crystal as opposed to nucleation from random points in a given region. Our results also differ from the limiting results found for this classical model. We use the invariant measure of an embedded Markov process to find the growth rate of the crystal in terms of the nucleation rates. Ergodic theorems are then used to derive explicit formulae for some stationary probabilities.

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Knight, F. B., and J. L. Steichen. "An interference problem with application to crystal growth." Advances in Applied Probability 36, no. 03 (September 2004): 725–46. http://dx.doi.org/10.1017/s0001867800013082.

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We model diffusion-controlled crystal growth as an interference problem. The crystal layers grow by nucleation (initiation of crystallization centers) followed by attachment of molecules to the nucleus. A forming crystal layer completes by either spreading across the length of the crystal or by colliding with another spreading crystal layer. This model differs from the classical Johnson-Mehl-Kolmogorov model in that nucleation happens only on boundaries of a ‘seed’ crystal as opposed to nucleation from random points in a given region. Our results also differ from the limiting results found for this classical model. We use the invariant measure of an embedded Markov process to find the growth rate of the crystal in terms of the nucleation rates. Ergodic theorems are then used to derive explicit formulae for some stationary probabilities.

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Jarvis, Richard A., and Andrew W. Woods. "The nucleation, growth and settling of crystals from a turbulently convecting fluid." Journal of Fluid Mechanics 273 (August 25, 1994): 83–107. http://dx.doi.org/10.1017/s0022112094001850.

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We present a new model to describe the thermal and compositional evolution of a binary alloy which is cooled from above. Explicit account is taken of the nucleation of crystals in the cold upper thermal boundary layer, the growth of crystals in the turbulently convecting interior, and their subsequent gravitational settling to the floor of the chamber. The crystallization of one solid phase only is considered. When the residence time of a typical crystal within the convecting bulk is short compared with the overall cooling time of the fluid, the crystal size distribution loses memory of earlier conditions in the fluid and the number density simply decays exponentially with the cube of the crystal size. A quasi-steady state exists in which the rate of crystal production is balanced by the rate of sedimentation at the floor, allowing the volume fraction of suspended crystals to remain small until convection ceases to be vigorous.We focus on the situation in which the latent heat released by solidification would far exceed the heat flux extracted through convection if the melt undercooling were maintained equal to the initial temperature difference applied at the cold upper boundary. In this case, either the growth or nucleation of crystals must be limited in order that the fluid continues to cool. Both the growth-limited and nucleation-limited regimes may develop during the cooling of an individual fluid body, depending upon the thermal boundary condition at the upper boundary of the convecting portion of the fluid.We calculate how the mean crystal size within the sedimented crystal pile evolves as the fluid cools. During the growth-limited regime, the mean crystal size in the crystal pile typically decreases with height, owing to the decrease in the extracted heat flux and the greater efficiency of crystal settling as the fluid layer becomes shallower. In contrast, during the nucleation-limited regime, the fluid undercooling may increase significantly as the fluid cools, and inverse grading (large crystals over small) is possible. We discuss the possible application of our theory to the cooling of large igneous intrusions.

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Jia, Yue Hui, Zi Dong Wang, Xin Gong, Pei Peng, Li Ming Ren, Yun Yi Fu, and Han Zhang. "Graphene Nucleation at Front Ends of Copper Twin Crystal." Materials Science Forum 852 (April 2016): 433–36. http://dx.doi.org/10.4028/www.scientific.net/msf.852.433.

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The graphene is easily grown on polycrystalline copper foils using metal-catalyzed chemical vapor deposition (CVD). Annealing twin readily occurred during this CVD process. However, there are only a few reports on the role of annealing twin on the graphene growth. In this paper, we present the investigations of the influence of copper twin crystal onthe nucleation of graphene. We found that there is no selective formation of graphene on these annealing twin crystal in general conditions of graphene growth.Interestingly, graphene preferentially nucleates at the front ends of twin crystals. We propose a micro-mechanism to explain the preferential graphene nucleation site based on spiral growth phenomena of copper twin crystals.This work may enable new possibilities for the controllable nucleation and wafer-scale growth of single-crystal graphene.

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De Yoreo, J. J. "Principles of Crystal Nucleation and Growth." Reviews in Mineralogy and Geochemistry 54, no. 1 (January 1, 2003): 57–93. http://dx.doi.org/10.2113/0540057.

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Daltin, A. L., M. Benaissa, and J. P. Chopart. "Nucleation and crystal growth in magnetoelectrodeposition." IOP Conference Series: Materials Science and Engineering 424 (October 13, 2018): 012022. http://dx.doi.org/10.1088/1757-899x/424/1/012022.

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Weinberg, Michael C., W. Howard Poisl, and Laszlo Granasy. "Crystal growth and classical nucleation theory." Comptes Rendus Chimie 5, no. 11 (November 2002): 765–71. http://dx.doi.org/10.1016/s1631-0748(02)01433-9.

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Saikumar, M. V., C. E. Glatz, and M. A. Larson. "Lysozyme crystal growth and nucleation kinetics." Journal of Crystal Growth 187, no. 2 (May 1998): 277–88. http://dx.doi.org/10.1016/s0022-0248(97)00853-1.

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Lacmann, R., A. Herden, and Ch Mayer. "Kinetics of Nucleation and Crystal Growth." Chemical Engineering & Technology 22, no. 4 (April 1999): 279–89. http://dx.doi.org/10.1002/(sici)1521-4125(199904)22:4<279::aid-ceat279>3.0.co;2-y.

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Sooksaen, Pat, Malin Rapp, and Kanokporn Potharin. "Microwave Assisted Method on the Morphology of Aluminium Doped ZnO Nanocrystals." Key Engineering Materials 608 (April 2014): 153–58. http://dx.doi.org/10.4028/www.scientific.net/kem.608.153.

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This study investigated the effect of aluminium dopant on ZnO morphologies synthesized by microwave assisted method. The precursors used were Zn (NO3)2.6H2O, NaOH and AlCl3.6H2O. The conditions for microwave heating were 160 and 640W, 10 min with 5s ON/15s OFF step. Microwave assisted heating generates heat to activate the formation of ZnO. Phase study was carried by X-ray diffraction which confirmed the formation of wurtzite structure of ZnO for all synthesized conditions. Microstructure was studied by a scanning electron microscope which revealed different crystal morphologies of ZnO at different amount of Al doping concentrations. ZnO rod was about 3-5 μm in length and 200 500 nm in cross section with hexagonal crystal plane. During microwave heating, nucleation of ZnO rods started at a point leading growth into larger flowers. In this work, it was suggested that Al acted as a nucleating agent and affected the c-axis orientation for ZnO crystal growth. Small needles/rod-like crystals were observed probably due to fast nucleation and a decrease of growth on (002) plane.

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Lorv, Janet S. H., David R. Rose, and Bernard R. Glick. "Bacterial Ice Crystal Controlling Proteins." Scientifica 2014 (2014): 1–20. http://dx.doi.org/10.1155/2014/976895.

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Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions.

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Rani, Radha, Kanika Thukral, Anuj Krishna, Geetanjali Sharma, Narayanasamy Vijayan, Brijesh Rathi, and Godavarthi Bhagavannarayana. "Synthesis and nucleation studies onL-leucine hydrobromide: a promising nonlinear optical material." Journal of Applied Crystallography 47, no. 6 (November 18, 2014): 1966–74. http://dx.doi.org/10.1107/s1600576714022663.

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To achieve good quality bulk size crystal growth, an assessment of the nucleation kinetics of a semi-organic L-leucine hydrobromide (L-LHBr) crystal was carried out using double-distilled water as solvent medium. The effect on metastable zone width (MSZW) with increasing temperature and on induction period with varied supersaturation level was determined experimentally and was found to be very well in accordance with the nucleation theory prospects. Thereafter, various other nucleation parameters, such as Gibbs free energy and interfacial energy, were also determined. The knowledge of these nucleation parameters indicated the requisite temperature domain and the appropriate growth technique, leading to the successful single-crystal growth of L-LHBr by slow cooling in the temperature range 298–291 K. The cooling rate of 0.25 K per day was optimized after repeated trials. X-ray diffraction and Raman analysis were performed on grown crystals for the verification of the material. High-resolution X-ray diffraction analysis was used to assess the crystalline perfection of the grown crystals. To further explore the properties of the grown crystals, photoluminescence and time decay studies, etching analysis, andZ-scan measurements were performed.

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31

Nikishina, Margarita A., and Dmitri V. Alexandrov. "Nucleation and growth dynamics of ellipsoidal crystals in metastable liquids." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, no. 2205 (July 19, 2021): 20200306. http://dx.doi.org/10.1098/rsta.2020.0306.

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When describing the growth of crystal ensembles from metastable solutions or melts, a significant deviation from a spherical shape is often observed. Experimental data show that the shape of growing crystals can often be considered ellipsoidal. The new theoretical models describing the transient nucleation of ellipsoidal particles and their growth with and without fluctuating rates at the intermediate stage of bulk phase transitions in metastable systems are considered. The nonlinear transport (diffusivity) of ellipsoidal crystals in the space of their volumes is taken into account in the Fokker–Planck equation allowing for fluctuating growth rates. The complete analytical solutions of integro-differential models of kinetic and balance equations are found and analysed. Our solutions show that the desupercooling dynamics is several times faster for ellipsoidal crystals as compared to spherical particles. In addition, the crystal-volume distribution function is lower and shifted to larger particle volumes when considering the growth of ellipsoidal crystals. What is more, this function is monotonically increasing to the maximum crystal size in the absence of fluctuations and is a bell-shaped curve when such fluctuations are taken into account. This article is part of the theme issue ‘Transport phenomena in complex systems (part 1)’.

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32

Cartwright, Julyan H. E., Antonio G. Checa, Bruno Escribano, and C. Ignacio Sainz-Díaz. "Crystal growth as an excitable medium." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1969 (June 28, 2012): 2866–76. http://dx.doi.org/10.1098/rsta.2011.0600.

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Crystal growth has been widely studied for many years, and, since the pioneering work of Burton, Cabrera and Frank, spirals and target patterns on the crystal surface have been understood as forms of tangential crystal growth mediated by defects and by two-dimensional nucleation. Similar spirals and target patterns are ubiquitous in physical systems describable as excitable media. Here, we demonstrate that this is not merely a superficial resemblance, that the physics of crystal growth can be set within the framework of an excitable medium, and that appreciating this correspondence may prove useful to both fields. Apart from solid crystals, we discuss how our model applies to the biomaterial nacre, formed by layer growth of a biological liquid crystal.

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33

Chen, Wen-Hao, Zuo-Yan Qin, Xu-Yong Tian, Xu-Hui Zhong, Zhen-Hua Sun, Bai-Kui Li, Rui-Sheng Zheng, Yuan Guo, and Hong-Lei Wu. "The Physical Vapor Transport Method for Bulk AlN Crystal Growth." Molecules 24, no. 8 (April 19, 2019): 1562. http://dx.doi.org/10.3390/molecules24081562.

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In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.

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Kishore Bandarapalle, Prasanna Raju Yalavarthi, and Chandra Sekhar Kothapalli Bannoth. "Antiurolithiatic activity of Berberis asiatica by In vitro calcium oxalate crystallization methods." International Journal of Research in Pharmaceutical Sciences 11, no. 4 (October 5, 2020): 6233–37. http://dx.doi.org/10.26452/ijrps.v11i4.3303.

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The primary objective of this research was to investigate the antiurolithiatic effect of the aqueous Heartwood extract of Berberis asiatica (AEBA) on in vitro crystallization methods. The antiurolithiatic behaviour was carried out in the presence and absence of AEBA at the concentration range of 100-1000 μg/ml by employing crystal nucleation, crystal aggregation, and crystal growth assay methods. Standard drug Cystone was made use of positive control in the concentration range of 100-1000 μg/ml. Inhibition efficiency of AEBA on crystal nucleation, crystal aggregation and crystal growth was spectrophotometrically validated. The percentage inhibition rate of crystal nucleation, crystal aggregation and crystal growth by AEBA and standard drug cystone was endorsed to be dose-dependent in nature. The half maximal inhibitory concentration (IC50) values of standard drug cystone on crystal nucleation, crystal aggregation and crystal growth were estimated to be 415.30±21.35, 573.7±65.53 and 566.20±62.06 μg/ml, respectively, while the AEBA, IC50 values were reckoned to be 839±69.13, 927.10±69.98 and 851±86.60 μg/ml, respectively. The findings of in vitro crystallization study disclosed that an aqueous Heartwood extract of Berberis asiatica possesses calcium oxalate crystal inhibition activity on crystal nucleation, crystal aggregation, and crystal growth recommended it as a potent and promising antiurolithiatic activity.

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Arunkumar, R., and D. Benny Anburaj. "Growth, Nucleation Kinetics and Structural Studies on L-Valine Piperazinium Single Crystals." Asian Journal of Chemistry 31, no. 9 (July 31, 2019): 1966–70. http://dx.doi.org/10.14233/ajchem.2019.22042.

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A single crystal of L-valine piperazinium was grown by slow growth technique. Structural studies confirm the monoclinic structure with space group P21. The solubility curve showing high soluble in water and peak shows positive solubility nature. A tiny nucleation formed at 10 ºC for room temperature process and it gradually increasing with respect process temperature. Induction period revels that time period for nucleation at constant temperature and it absorbed that in (10 ºC) 500 s for room temperature. The calculated interfacial tension values are greater than one order other amino acid based piperazinium. By using growth parameters bulk L-valine piperazinium crystal were harvested and single crystal XRD confirms that formation of L-valine piperazinium crystals.

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36

Sukjai, Onanong, Piyapong Asanithi, Pichet Limsuwan, and Supanee Limsuwan. "Effect of Sericin Protein on Growth of Hydroxyapatite over Surface of Silk Fibers Using Simulated Body Fluid." Advanced Materials Research 622-623 (December 2012): 1764–67. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.1764.

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Crystal of hydroxyapatite (HAp) was grown on silk fibers using simulated body fluid (SBF) at a temperature of 37 °C. Effect of SBF concentrations and sericin protein on the growth of HAp crystals on the silk fiber was discussed. The results showed that sericin protein was an important parameter to induce HAp crystals. Furthermore, the crystal was grown perfectly for both 1.0 and 1.5  standard SBF concentrations but difference in HAp crystal size. Sericin protein may lower nucleation barrier and high surface area to absorb SBF for HAp nucleation. These results may be a new research topic on HAp crystallization using protein as a seed. It may lead to further improvement and applied for many HAp-based biomaterial applications.

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37

Baht, Gurpreet S., Jason O'Young, Antonia Borovina, Hong Chen, Coralee E. Tye, Mikko Karttunen, Gilles A. Lajoie, Graeme K. Hunter, and Harvey A. Goldberg. "Phosphorylation of Ser136 is critical for potent bone sialoprotein-mediated nucleation of hydroxyapatite crystals." Biochemical Journal 428, no. 3 (May 27, 2010): 385–95. http://dx.doi.org/10.1042/bj20091864.

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Acidic phosphoproteins of mineralized tissues such as bone and dentin are believed to play important roles in HA (hydroxyapatite) nucleation and growth. BSP (bone sialoprotein) is the most potent known nucleator of HA, an activity that is thought to be dependent on phosphorylation of the protein. The present study identifies the role phosphate groups play in mineral formation. Recombinant BSP and peptides corresponding to residues 1–100 and 133–205 of the rat sequence were phosphorylated with CK2 (protein kinase CK2). Phosphorylation increased the nucleating activity of BSP and BSP-(133–205), but not BSP-(1–100). MS analysis revealed that the major site phosphorylated within BSP-(133–205) was Ser136, a site adjacent to the series of contiguous glutamate residues previously implicated in HA nucleation. The critical role of phosphorylated Ser136 in HA nucleation was confirmed by site-directed mutagenesis and functional analyses. Furthermore, peptides corresponding to the 133–148 sequence of rat BSP were synthesized with or without a phosphate group on Ser136. As expected, the phosphopeptide was a more potent nucleator. The mechanism of nucleation was investigated using molecular-dynamics simulations analysing BSP-(133–148) interacting with the {100} crystal face of HA. Both phosphorylated and non-phosphorylated sequences adsorbed to HA in extended conformations with alternating residues in contact with and facing away from the crystal face. However, this alternating-residue pattern was more pronounced when Ser136 was phosphorylated. These studies demonstrate a critical role for Ser136 phosphorylation in BSP-mediated HA nucleation and identify a unique mode of interaction between the nucleating site of the protein and the {100} face of HA.

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38

Nývlt, Jaroslav, Věra Šnoblová, and Miloslav Karel. "Crystallization kinetics for the system CuSO4-ZnSO4-H2O forming solid solutions." Collection of Czechoslovak Chemical Communications 51, no. 11 (1986): 2473–80. http://dx.doi.org/10.1135/cccc19862473.

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The three-component system CuSO4-ZnSO4-H2O forms three types of solid solution. Metastable zone widths measured for selected solution compositions at two cooling rates were used to calculate the kinetic parameters of nucleation. The rate of crystal growth was measured by the fluidized bed method. The results show that the addition of Zn2+ to a solution of CuSO4 increases both the nucleation and crystal growth rates, whereas Cu2+ added to a solution of ZnSO4 retards the nucleation rate and slightly increases the rate of crystal growth. The nucleation rate (the metastable zone width) is substantially more sensitive to the addition of a second component than is the rate of crystal growth. The crystal growth rate is controlled by a diffusion mechanism.

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39

Jing, Mengfan, Hong Jiang, Yilan Guo, Zhiqiang Wu, and Qiang Fu. "Transcrystallization of poly(l-lactic acid) on the surface of reduced graphene oxide fibers." RSC Advances 6, no. 102 (2016): 100090–97. http://dx.doi.org/10.1039/c6ra18762e.

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Transcrystalline layer could form between rGOF and PLLA. The good nucleating ability of rGOF could be quantitatively characterized based on the theories of heterogeneous nucleation and crystal growth rate.

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40

Lini, Freshsya Zata, Dhanang Edy Pratama, and Tu Lee. "Co-Crystallization Kinetics of 2:1 Benzoic Acid–Sodium Benzoate Co-Crystal: The Effect of Templating Molecules in a Solution." Crystals 11, no. 7 (July 12, 2021): 812. http://dx.doi.org/10.3390/cryst11070812.

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The addition of dissolved templating molecules in crystallization will create “supramolecular assemblies” within the solution, serving as “anchor points” for the solute molecules to nucleate and grow. In this work, nucleation and crystal growth kinetics of 2:1 benzoic acid (HBz)–sodium benzoate (NaBz) co-crystallization with or without templates in a solution were analyzed by monitoring the concentration of the mother liquor during cooling crystallization. The results showed that the addition of the dissolved 2:1 or 1:1 HBz–NaBz co-crystals as templating molecules could reduce the critical free energy barrier of 2:1 HBz–NaBz co-crystal during its nucleation, but did not significantly affect the order of crystal growth rate. On the other hand, the critical free energy barrier of the nucleation process was increased if dissolved NaBz was used as a templating molecule, while a significant rise in the order of crystal growth rate occurred. The crystal habit obtained from the NaBz-templated system was needle-like, suggesting that sodium–sodium coordination chains of NaBz supramolecular assemblies in the solution phase were responsible for creating elongated crystals. Conversely, a large prismatic crystal habit found in non-templated and 2:1 and 1:1 HBz–NaBz co-crystal-templated systems implied that those templating molecules formed sparsely interconnected supramolecular assemblies in the solution phase.

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41

Przybylska, M. "A double cell for controlling nucleation and growth of protein crystals." Journal of Applied Crystallography 22, no. 2 (April 1, 1989): 115–18. http://dx.doi.org/10.1107/s0021889888012270.

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A simple device for protein crystallization is described that consists of two connected cells, one for the hanging- or sitting-drop vapour diffusion method and the other for changing the concentration of the reservoir solution. It has been found useful for decoupling crystal nucleation from crystal growth, for improving the size and the stability of crystals, and in the preparation of heavy-atom derivatives.

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42

Quattrosoldi, Silvia, Nadia Lotti, Michelina Soccio, Christoph Schick, and René Androsch. "Stability of Crystal Nuclei of Poly (butylene isophthalate) Formed Near the Glass Transition Temperature." Polymers 12, no. 5 (May 11, 2020): 1099. http://dx.doi.org/10.3390/polym12051099.

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Tammann’s two-stage crystal-nuclei-development method is applied for analysis of the thermal stability of homogenously formed crystal nuclei of poly(butylene isophthalate) (PBI) as well as their possible reorganization on transferring them to the growth temperature, using fast scanning chip calorimetry. Crystal nuclei were formed at 50 °C, that is, at a temperature only slightly higher than the glass transition temperature, and developed to crystals within a pre-defined time at the growth temperature of 85 °C. The number of nuclei, overcritical at the growth temperature, was detected as a function of the transfer-conditions (maximum temperature, heating rate) by evaluation of the developed crystal fraction. For different size-distributions of crystal nuclei, as controlled by the nucleation time, there is detected distinct reduction of the nuclei number on heating to maximum temperatures higher than about 90 to 110 °C, with the latter value holding for longer nucleation time. Longer nucleation allows for both increasing the absolute nuclei number and generation of an increased fraction of larger nuclei. Heating at 1000 K/s to 140–150 °C causes “melting” of even the most stable nuclei. While direct transfer of crystal nuclei from the nucleation temperature (50 °C) to the growth temperature (85 °C) reveals negligible effect of the transfer-heating rate, in-between heating to higher temperatures is connected with distinct nuclei-reorganization above 85 °C on heating slower than 1000–10.000 K/s. The performed study not only provides specific valuable information about the thermal characteristics of crystal nuclei of PBI but also highlights the importance of proper design of Tammann’s nuclei development experiment for analysis of nuclei numbers. With the evaluation of critical rates of temperature-change for suppression of non-isothermal formation of both nuclei and crystals, the kinetics of crystallization of the slow crystallizing PBI is further quantified.

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Arzig, Matthias, Michael Salamon, Norman Uhlmann, and Peter J. Wellmann. "Tracking of the Growth Interface during PVT-Growth of SiC Boules Using a X-Ray Computed Tomography Setup." Materials Science Forum 963 (July 2019): 14–17. http://dx.doi.org/10.4028/www.scientific.net/msf.963.14.

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A crystal comprising various polytype switches was analyzed in detail. A very flat temperature profile together with an on axis seed are used to increase the probability for the nucleation of foreign polytypes during growth. Formation of foreign polytype occurred from thin lamella propagating from the edge of the main facet to the crystal rim as well as from 2D nucleation. The evolution of the crystal surface during the growth time is visualized using in-situ X-Ray computed tomography. Two concurrent growth centers are identified in the beginning of the growth process. Nucleation and lateral growth of foreign polytypes in the main facet area can be traced during the growth process.

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Huynh, Nam N., Cheng Lu, Guillaume Michal, and A. Kiet Tieu. "A Misorientation Dependent Criterion of Crack Opening in FCC Single Crystal." Materials Science Forum 773-774 (November 2013): 293–311. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.293.

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This paper proposes a criterion for crack opening in FCC single crystals based on analyses of lattice orientation and interface energy of two adjacent crystals in a crystal plasticity finite element model (CPFEM). It also demonstrates the implementation of the criterion in Abaqus/Standard to simulate crack initiation and propagation in single-edged notch single crystal aluminium samples. Elements in the FEM mesh that have crystalline structures satisfying the crack opening criterion are removed from the mesh at the end of every loading step and FEM analyses are restarted on the new mesh in the next loading step. Removed elements effectively act as voids in the material due to crack nucleation. Similarly, the coalescence of newly removed elements at the end of a loading step with the existent ones simulates crack growth in the material. Two advantages of this approach are noted. Firstly, crack nucleation and its subsequent growth in the material is simulated solely based on lattice evolution history in the material without any presumptions of crack paths or regions where cracks are likely to occur. Secondly, as the criterion for crack nucleation is evaluated based on, and thus changes with, the lattice evolution during loading, a predefined energy criterion for crack opening, which could be erroneous, is avoided. Preliminary results of void nucleation and void growth around the notch tip in Cube and Brass oriented samples using CPFEM modelling appear to agree with molecular dynamics simulations of void growth in FCC single crystals.

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Kim, Young Seok, Kyu Ho Lee, Tae Ho Kim, Young Joon Jung, S. H. Yim, and Bong Ki Ryu. "Crystallization Kinetics for Synthesis Hyper-Structure in P₂O₅-ZnO-B₂O₃-BaO-Al₂O₃-TiO₂ Glass Ceramic Composite." Materials Science Forum 569 (January 2008): 153–56. http://dx.doi.org/10.4028/www.scientific.net/msf.569.153.

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The nucleation and crystallization kinetics of P2O5-B2O3-ZnO-BaO-Al2O3-TiO2 crystals in bulk glass in which this crystals were found to crystallize in the heating process of the glass, were studied by non-isothermal measurements using differential thermal analysis (DTA). A nucleation rate-temperature was determined by plotting either the reciprocal of the temperature corresponding to the crystallization peak maximum, 1/Tp, or the height of the crystallization peak, (*T)p, as a function of nucleation temperature, Tn. The temperature where nucleation can occur for this glass ranges from 700°C to 890°C and the temperature for maximum nucleation is 760±5°C. The correct activation energy for crystallization, Ec, for this glass is the same for surface and/or bulk crystallization, and is 533±15°CkJ/mol. The analysis of the crystallization data with the Kissinger equation and the Marotta equation yields the correct value for Ec only crystal growth occurs on a fixed number of nuclei. The crystallization process of a sample heat treated at the temperature of the maximum nucleation rate was fitted to kinetic equations with an Avrami constant, n ≈2 and a dimensionality of crystal growth, m ≈2.

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Khvorostyanov, Vitaly I., and Judith A. Curry. "The Theory of Ice Nucleation by Heterogeneous Freezing of Deliquescent Mixed CCN. Part II: Parcel Model Simulation." Journal of the Atmospheric Sciences 62, no. 2 (February 1, 2005): 261–85. http://dx.doi.org/10.1175/jas-3367.1.

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Abstract The new theory of ice nucleation by heterogeneous freezing of deliquescent mixed cloud condensation nuclei (CCN) presented in Part I is incorporated into a parcel model with explicit water and ice bin microphysics to simulate the process of ice nucleation under transient thermodynamic conditions. Simulations are conducted over the temperature range −4° to −60°C, with vertical velocities varying from 1 to 100 cm s−1, for varying initial relative humidities and aerosol characteristics. These simulations show that the same CCN that are responsible for the drop nucleation may initiate crystal nucleation and can be identified as ice nuclei (IN) when crystals form. The simulated nucleation rates and concentrations of nucleated crystals depend on temperature and supersaturation simultaneously, showing good agreement with observations but with noticeable differences when compared with classical temperature-only and supersaturation-only parameterizations. The kinetics of heterogeneous ice nucleation exhibits a negative feedback via water supersaturation, whereby ice nucleation depends on the water supersaturation that is diminished by ice crystal diffusional growth. This feedback is stronger than the corresponding feedback for drop nucleation, and may explain discrepancies between observed ice nuclei concentrations and ice crystal concentrations, the very small fraction of CCN that may serve as IN, and the much smaller crystal concentrations as compared to drop concentrations. The relative importance of heterogeneous versus homogeneous nucleation is examined for a variety of cloud conditions. Based on these calculations, a simple parameterization for ice crystal concentration is suggested for use in cloud models and large-scale models.

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47

Rosenberger, Franz, and Edward J. Meehan. "Control of nucleation and growth in protein crystal growth." Journal of Crystal Growth 90, no. 1-3 (July 1988): 74–78. http://dx.doi.org/10.1016/0022-0248(88)90300-4.

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48

Alexandrov, D. V. "Nucleation and crystal growth in binary systems." Journal of Physics A: Mathematical and Theoretical 47, no. 12 (March 10, 2014): 125102. http://dx.doi.org/10.1088/1751-8113/47/12/125102.

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Privitera, S., C. Bongiorno, E. Rimini, and R. Zonca. "Crystal nucleation and growth processes in Ge2Sb2Te5." Applied Physics Letters 84, no. 22 (May 31, 2004): 4448–50. http://dx.doi.org/10.1063/1.1759063.

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50

Delhommelle, J. "Crystal nucleation and growth from supercooled melts." Molecular Simulation 37, no. 7 (June 2011): 613–20. http://dx.doi.org/10.1080/08927022.2011.566611.

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Journal articles on the topic 'Nucleation and Crystal Growth'

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