3 THE INFLUENCE OF IMPURITIES AND SOLVENTS ON CRYSTALLIZATION Paul A. Meenan, Stephen R. Anderson, and Diana L. Klug 3.1. INTRODUCTION In many instances, small amounts of impurities have dramatic effects on crystal growth, morphology, and nucleation.

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Aug 11, 2018· The key difference between homogeneous and heterogeneous nucleation is that the homogeneous nucleation occurs away from the surface of the system whereas the heterogeneous nucleation occurs at the surface of the system.. Nucleation is the initial step of the process of forming a new thermodynamic phase or a new structure via self-organization. There are two types of it; they are …

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Jun 22, 2016· One obvious example is the formation of ice, which influences global phenomena such as climate change, 1,2 as well as processes happening at the nanoscale, such as intracellular freezing. 3,4 On the other hand, controlling nucleation of molecular crystals from solutions is of great importance to pharmaceuticals, particularly in the context of ...

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The influence of defects on nucleation rate and the orientation of the film is emphasized. Specific examples of impurity effects, irradiation effects and the influence of amorphous layers are discussed in detail. Evidence is shown that the formation of multiply twinned particles is …

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Aug 19, 2005· Impurities affect the nucleation, growth, and structure of crystals. Here we report the effect of large, spherical, polymethylmethacrylate impurities on the crystal growth of monodisperse, hard, polymethylmethacrylate colloids in a density- and optically matching apolar solvent mixture. Crystal growth, initiated at the bottom of the sample, was studied by imaging sequences of two-dimensional ...

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Jun 23, 2020· Thermal analysis of the same samples also showed significant differences (Fig. 1b). S. newyorkensis was characterised by the occurrence of three …

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impurities is expected to influence the growth kinetics, habit modification as well as ... nucleation rate, etc. by doping with bimetall ic impurities for growing bulk KAP crystals. ... where V is the specific volume and is obtained by the expression,

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This work describes the influence of non carbon elements, oxygen, boron, and silicon, in diamond CVD, including the nucleation of diamond particles in the gas phase and growth of diamond films by a cyclic process. Gas phase nucleation of diamond was achieved by microwave plasma decomposition of methane and a dopant gas, sometimes with the addition of hydrogen.

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The striking ability of impurities to significantly influence crystallization processes is a topic of paramount interest in the pharmaceutical industry. Despite being present in small quantities, impurities tend to considerably change a crystallization process as well as the final crystalline product. In the present work, the effect of two markedly different impurities 4-nitrophenol and 4 ...

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1 Influence of particle size on ice nucleation and growth during the freeze-casting process Sylvain Deville1, Eric Maire 2, Audrey Lasalle1, Agnes Bogner, Catherine Gauthier, Jérôme Leloup 1, Christian Guizard 1 Laboratoire de Synthèse et Fonctionnalisationdes Céramiques, UMR3080 CNRS/Saint-Gobain CREE, 550 Avenue Alphonse Jauffret, BP 20224, 84306

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T1 - Influence of polyethylenimine on the precipitation process of lead sulfate crystals. AU - Katayama, Akio. AU - Sakuma, Takahiro. AU - Hirasawa, Izumi. PY - 2004/1/9. Y1 - 2004/1/9. N2 - Crystals of lead sulfate were precipitated in a solution of polyethylenimine (PEI) using a …

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Small concentrations of specific impurities in supersaturated solutions can enable nucleation, change the growth and influence aggregation and the morphology of the crystals during growth ...

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The influence of impurities on nucleation is poorly understood and cannot be clearly predicted. It is known that homogeneous nucleation will occur earlier in the presence of foreign particles. Most of the literature dealing with the influence of impurities on nucleation kinetics is about homogeneous [4] or heterogeneous nucleation [5], [6] .

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@article{osti_296785, title = {The influence of surface morphology and oxide microstructure on the nucleation and growth of uranium hydride on alpha uranium}, author = {Hanrahan, Jr, R J and Hawley, M E and Brown, G W}, abstractNote = {While the bulk kinetics of the uranium-hydrogen reaction are well understood, the mechanisms underlying the initial nucleation of uranium hydride on uranium ...

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Bekijk het profiel van René Steendam op LinkedIn, de grootste professionele community ter wereld. René heeft 10 functies op zijn of haar profiel. Bekijk het volledige profiel op LinkedIn om de connecties van René en vacatures bij vergelijkbare bedrijven te zien.

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Oct 08, 2019· Using notions from classic materials science, we expand our understanding of the macroscopic morphospace of possible molluscan shell shapes to the level of possible ultrastructures that comprise them. This provides us with a unique opportunity to explore this morphospace using well-developed analytical, theoretical, and numerical tools and to test the effects of a discrete number of …

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Despite being present in small quantities, impurities tend to considerably change a crystallization process as well as the final crystalline product. In the present work, the effect of two markedly different impurities 4-nitrophenol and 4′-chloroacetanilide on the solubility, nucleation, and crystallization of paracetamol is described.

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2 • Some examples of heterogeneous nucleation include: 1) Bubbles of carbon dioxide nucleate shortly on the inner surface of a container after it is gently opened (as the pressure is released). Since the surface is smooth and flat (specific surface area is small),

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Heterogeneous nucleation, nucleation with the nucleus at a surface, is much more common than homogeneous nucleation. For example, in the nucleation of ice from supercooled water droplets, purifying the water to remove all or almost all impurities results in water droplets that freeze below around - 35 °C, whereas water that contains impurities may freeze at - 5 °C or warmer.

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The influence of solvent and impurities on the structure and growth rates of faces is discussed in the chapter, along with its effect on the incorporation of impurities.

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Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors Andrea Angulo1, Peter van der Linde2, Han Gardeniers2, Miguel Modestino1,*, David Fernández Rivas2,* 1Department of Chemical and Biomolecular Engineering, Tandon School of Engineering, New York University. 6 Metrotech Center, Brooklyn, NY 11201, U.S.A. 2Mesoscale Chemical Systems Group, …

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Jan 21, 2013· NUCLEATION &CRYSTALLIZATION 2. ... NUCLEATION• The total free energy of solid-liquid system changes with the size of the solid.• The solid is an "Embryo", if it's radius is less than the critical radius and is a "Nucleus" if its radius is greater than the critical radius.• "The critical radius is the minimum size of the ...

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Apr 01, 2014· Nucleation and Growth of Protein Crystals: General Principles and Assays. Methods Enzymol. 114, 77–112. Feigelson, R. S. (1988). The relevance of small molecule crystal growth theories and techniques to the growth of biological macromolecules. J. Cryst. Growth, 90, 1–13. Frank, F. C. (1949). The influence of dislocations on crystal growth.

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The influence of defects on nucleation rate and the orientation of the film is emphasized. Specific examples of Impurity effects, Irradiation effects and the Influence of Amorphous layers are discussed in detail. Evi-dence is shown that the formation of Multiply Twinned Particles is a …

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A mixture of ceramide (CER) and lecithin (LEC) at specific ratios was capable of forming oleogels in sunflower oil triggered by adding a trace amount of water. It was noted that the addition of water at different temperatures (TW) resulted in different gelation behaviors and microstructures. To better illumi

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impossible to predict the influence of impurities or solvents on crystallization, or explain such diverse processes as secondary nucleation and inclusion formation. 3.2.1. THE ROLE OF THE SOLID STATE IN SHAPE DEVELOPMENT A crystal can be defined as a material consisting of an ordered solid array (lattice) of atoms or molecules exhibiting long-range

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nucleation describes nucleation catalyzed by an active nuclea-tion center. The latter has a different chemical structure than the medium to be crystallized. Plenty of work exists dealing with the influence of primary nucleation on the crystallization of emulsions [3,9,11]. Secondary nucleation occurs when crystals are already pres-

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The influence of defects on nucleation rate and the orientation of the film is emphasized. Specific examples of impurity effects, irradiation effects and the influence of amorphous layers are discussed in detail. Evidence is shown that the formation of multiply twinned particles is …

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