Artykuły w czasopismach: „Homogeneous nucleation theory”

1

Oxtoby, D. W. "Homogeneous nucleation: theory and experiment". Journal of Physics: Condensed Matter 10, nr 4 (2.02.1998): 897. http://dx.doi.org/10.1088/0953-8984/10/4/019.

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2

Oxtoby, D. W. "Homogeneous nucleation: theory and experiment". Journal of Physics: Condensed Matter 4, nr 38 (21.09.1992): 7627–50. http://dx.doi.org/10.1088/0953-8984/4/38/001.

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3

Zhukhovitskii, D. I. "Size‐corrected theory of homogeneous nucleation". Journal of Chemical Physics 101, nr 6 (15.09.1994): 5076–80. http://dx.doi.org/10.1063/1.467364.

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4

Hartmann, S., D. Niedermeier, J. Voigtländer, T. Clauss, R. A. Shaw, H. Wex, A. Kiselev i F. Stratmann. "The Leipzig Cloud Interaction Simulator (LACIS): operating principle and theoretical studies concerning homogeneous and heterogeneous ice nucleation". Atmospheric Chemistry and Physics Discussions 10, nr 11 (1.11.2010): 25577–617. http://dx.doi.org/10.5194/acpd-10-25577-2010.

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Abstract. At the Leipzig Cloud Interaction Simulator (LACIS) experiments investigating homogeneous and heterogeneous nucleation of ice (particularly immersion freezing in the latter case) have been carried out. Here both the physical LACIS setup and the numerical model developed to design experiments at LACIS and interpret their results are presented in detail. Combining results from the numerical model with experimental data, it was found that for the experimental parameter space considered, classical homogeneous ice nucleation theory is able to predict the freezing behavior of highly diluted ammonium sulfate solution droplets, while classical heterogeneous ice nucleation theory, together with the assumption of a constant contact angle, fails to predict the immersion freezing behavior of surrogate mineral dust particles (Arizona Test Dust, ATD). The main reason for this failure is the compared to experimental data apparently overly strong temperature dependence of the nucleation rate coefficient. Assuming, in the numerical model, Classical Nucleation Theory (CNT) for homogeneous ice nucleation and a CNT-based parameterization for the nucleation rate coefficient in the immersion freezing mode, recently published by our group, it was found that even for a relatively effective ice nucleating agent such as pure ATD, there is a temperature range where homogeneous ice nucleation is dominant. The main explanation is the apparently different temperature dependencies of the two freezing mechanisms. Finally, reviewing the assumptions made during the derivation of the parameterization, it was found that the assumption of constant temperature during ice nucleation and the chosen nucleation time were highly justified, underlining the applicability of both the method to determine the fitting coefficients in the parameterization equation, and the validity of the parameterization concept itself.

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5

Hartmann, S., D. Niedermeier, J. Voigtländer, T. Clauss, R. A. Shaw, H. Wex, A. Kiselev i F. Stratmann. "Homogeneous and heterogeneous ice nucleation at LACIS: operating principle and theoretical studies". Atmospheric Chemistry and Physics 11, nr 4 (25.02.2011): 1753–67. http://dx.doi.org/10.5194/acp-11-1753-2011.

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Abstract. At the Leipzig Aerosol Cloud Interaction Simulator (LACIS) experiments investigating homogeneous and heterogeneous nucleation of ice (particularly immersion freezing in the latter case) have been carried out. Here both the physical LACIS setup and the numerical model developed to design experiments at LACIS and interpret their results are presented in detail. Combining results from the numerical model with experimental data, it was found that for the experimental parameter space considered, classical homogeneous ice nucleation theory is able to predict the freezing behavior of highly diluted ammonium sulfate solution droplets, while classical heterogeneous ice nucleation theory, together with the assumption of a constant contact angle, fails to predict the immersion freezing behavior of surrogate mineral dust particles (Arizona Test Dust, ATD). The main reason for this failure is the compared to experimental data apparently overly strong temperature dependence of the nucleation rate coefficient. Assuming, in the numerical model, Classical Nucleation Theory (CNT) for homogeneous ice nucleation and a CNT-based parameterization for the nucleation rate coefficient in the immersion freezing mode, recently published by our group, it was found that even for a relatively effective ice nucleating agent such as pure ATD, there is a temperature range where homogeneous ice nucleation is dominant. The main explanation is the apparently different temperature dependencies of the two freezing mechanisms. Finally, reviewing the assumptions made during the derivation of the CNT-based parameterization for immersion freezing, it was found that the assumption of constant temperature during ice nucleation and the chosen ice nucleation time were justified, underlining the applicability of the method to determine the fitting coefficients in the parameterization equation.

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6

Smolík, Jiří, i Vladimír Ždímal. "Homogeneous Nucleation of Supersaturated Vapors. A Comparison of Experimental Results with Theory". Collection of Czechoslovak Chemical Communications 58, nr 12 (1993): 2831–35. http://dx.doi.org/10.1135/cccc19932831.

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Some theories of homogeneous nucleation based on liquid droplet model were tested by comparing with experimental supersaturations of naphthalene, phthalic anhydride, stearic acid, bis(2-ethylhexyl) phthalate, and bis(2-ethylhexyl) sebacate required to bring about the rate of homogeneous nucleation of about 5 drops/cm3 s-1. It was found that except for highly polar substance phthalic anhydride, the classical (Becker-Doring) theory of homogeneous nucleation, if suitably scaled, yielded fairly good predictions of the nucleation behaviour.

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7

Ito, Kimihisa. "Thermochemical Explanation of Classical Homogeneous Nucleation Theory." Materia Japan 36, nr 12 (1997): 1127–30. http://dx.doi.org/10.2320/materia.36.1127.

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8

Kalikmanov, V. I., i M. E. H. van Dongen. "Semiphenomenological theory of homogeneous vapor–liquid nucleation". Journal of Chemical Physics 103, nr 10 (8.09.1995): 4250–55. http://dx.doi.org/10.1063/1.470662.

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9

Katz, J. L. "Homogeneous nucleation theory and experiment: A survey". Pure and Applied Chemistry 64, nr 11 (1.01.1992): 1661–66. http://dx.doi.org/10.1351/pac199264111661.

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10

Shen, Vincent K., i Pablo G. Debenedetti. "A kinetic theory of homogeneous bubble nucleation". Journal of Chemical Physics 118, nr 2 (8.01.2003): 768–83. http://dx.doi.org/10.1063/1.1526836.

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11

Hienola, A. I., H. Vehkamäki, I. Riipinen i M. Kulmala. "Homogeneous vs. heterogeneous nucleation in water-dicarboxylic acid systems". Atmospheric Chemistry and Physics Discussions 8, nr 5 (21.10.2008): 18295–321. http://dx.doi.org/10.5194/acpd-8-18295-2008.

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Abstract. Binary heterogeneous nucleation of water-succinic/glutaric/malonic/adipic acid on nanometer-sized particles is investigated within the frame of classical heterogeneous nucleation theory. Homogeneous nucleation is also included for comparison. It is found that the nucleation probabilities depend on the contact angle and on the size of the seed particles. New thermodynamical properties, such as saturation vapor pressure, density and surface tension for all the dicarboxylic acid aqueous solutions are included in the calculations. While the new surface tension and density formulations do not bring any significant difference in the computed nucleation rate for homogeneous nucleation for succinic and glutaric acids, the use of the newly derived equations for the vapor pressure decrease the acid concentrations in gas phase with 3 orders of magnitude. According to our calculations, the binary heterogeneous nucleation of succinic acid-water and glutaric acid-water – although it requires a 3–4 orders of magnitude lower vapor concentrations than the homogeneous nucleation – cannot take place in atmospheric conditions. On the other hand binary homogeneous nucleation of adipic acid-water systems might be possible in conditions occuring in upper boundary layer. However, a more detailed characterization of the interaction between the surface and the molecules of the nucleating vapor should be considered in the future.

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12

Hienola, A. I., H. Vehkamäki, I. Riipinen i M. Kulmala. "Homogeneous vs. heterogeneous nucleation in water-dicarboxylic acid systems". Atmospheric Chemistry and Physics 9, nr 6 (17.03.2009): 1873–81. http://dx.doi.org/10.5194/acp-9-1873-2009.

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Abstract. Binary heterogeneous nucleation of water-succinic/glutaric/malonic/adipic acid on nanometer-sized particles is investigated within the frame of classical heterogeneous nucleation theory. Homogeneous nucleation is also included for comparison. It is found that the nucleation probabilities depend on the contact angle and on the size of the seed particles. New thermodynamical properties, such as saturation vapor pressure, density and surface tension for all the dicarboxylic acid aqueous solutions are included in the calculations. While the new surface tension and density formulations do not bring any significant difference in the computed nucleation rate for homogeneous nucleation for succinic and glutaric acids, the use of the newly derived equations for the vapor pressure decrease the acid concentrations in gas phase by 3 orders of magnitude. According to our calculations, the binary heterogeneous nucleation of succinic acid-water and glutaric acid-water – although it requires a 3–4 orders of magnitude lower vapor concentrations than the homogeneous nucleation – cannot take place under atmospheric conditions. On the other hand binary homogeneous nucleation of adipic acid-water systems might be possible under conditions occuring in upper boundary layer. However, a more detailed characterization of the interaction between the surface and the molecules of the nucleating vapor should be considered in the future.

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13

Cahoon, J. R. "On the nucleation rate for the solidification of metals". Canadian Journal of Physics 91, nr 2 (luty 2013): 140–45. http://dx.doi.org/10.1139/cjp-2011-0479.

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The classical homogeneous nucleation rate theory for the solidification of metals has been in use for over 50 years, but it is almost universally used incorrectly. Because of this, solid–liquid surface energies calculated from nucleation rate theory are also incorrect. Herein, the correct usage of the homogeneous nucleation rate equation for the solidification of metals is presented. It is shown that because of the assumption of thermodynamic equilibrium, the homogeneous nucleation rate cannot be accurately calculated but is likely in the range 1012–1014 s−1. Also, it is shown that the homogeneous nucleation temperature for a pure metal is essentially a material property. Calculations for the solidification of pure Ni are included.

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14

Smith, Kenneth A., Marc Hodes i Peter Griffith. "On the Potential for Homogeneous Nucleation of Salt From Aqueous Solution in a Natural Convection Boundary Layer". Journal of Heat Transfer 124, nr 5 (11.09.2002): 930–37. http://dx.doi.org/10.1115/1.1494089.

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Recent studies have examined the rate of salt deposition by natural convection on a cylinder heated above the solubility temperature corresponding to the concentration of salt in the surrounding solution at conditions typical of the Supercritical Water Oxidation (SCWO) process (Hodes et al. [1,2], Hodes [3]). The total deposition rate of salt on the cylinder is the sum of the rate of deposition at the salt layer-solution interface (SLSI) formed on the cylinder and that within the porous salt layer. The rate of deposition at the SLSI cannot be computed without determining whether or not salt nucleates homogeneously in the adjacent (natural convection) boundary layer. A methodology to determine whether or not homogeneous nucleation in the boundary layer is possible is presented here. Temperature and concentration profiles in the boundary layer are computed under the assumption that homogeneous nucleation does not occur. If, under this assumption, supersaturation does not occur, homogeneous nucleation is impossible. If supersaturation is present, homogeneous nucleation may or may not occur depending on the amount of metastability the solution can tolerate. It is shown that the Lewis number is the critical solution property in determining whether or not homogeneous nucleation is possible and a simple formula is developed to predict the Lewis number below which homogeneous nucleation is impossible for a given solubility boundary and set of operating conditions. Finally, the theory is shown to be consistent with experimental observations for which homogeneous nucleation is absent or present.

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15

Yang, C. H., i H. Qiu. "Theory of homogeneous nucleation: A chemical kinetic view". Journal of Chemical Physics 84, nr 1 (styczeń 1986): 416–23. http://dx.doi.org/10.1063/1.450154.

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16

Barrett, J. C., C. F. Clement i I. J. Ford. "Energy fluctuations in homogeneous nucleation theory for aerosols". Journal of Physics A: Mathematical and General 26, nr 3 (7.02.1993): 529–48. http://dx.doi.org/10.1088/0305-4470/26/3/016.

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17

Strumia, A., N. Tetradis i C. Wetterich. "The region of validity of homogeneous nucleation theory". Physics Letters B 467, nr 3-4 (listopad 1999): 279–88. http://dx.doi.org/10.1016/s0370-2693(99)01158-2.

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18

Al’tman, I. S., I. E. Agranovskii, M. Choi i V. A. Zagainov. "To the theory of homogeneous nucleation: Cluster energy". Russian Journal of Physical Chemistry A 82, nr 12 (27.11.2008): 2097–102. http://dx.doi.org/10.1134/s0036024408120224.

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19

Kalikmanov, V. I., i M. E. H. van Dongen. "Quasi-one-component theory of homogeneous binary nucleation". Physical Review E 51, nr 5 (1.05.1995): 4391–99. http://dx.doi.org/10.1103/physreve.51.4391.

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20

Derjaguin, B. V. "Statistical thermodynamics of nucleation. Theory of homogeneous condensation". Progress in Surface Science 45, nr 1-4 (styczeń 1994): 10–14. http://dx.doi.org/10.1016/0079-6816(94)90025-6.

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21

Ford, I. J., J. C. Barrett i M. Lazaridis. "Uncertainties in cluster energies in homogeneous nucleation theory". Journal of Aerosol Science 24, nr 5 (lipiec 1993): 581–88. http://dx.doi.org/10.1016/0021-8502(93)90015-2.

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22

Alpert, P. A., J. Y. Aller i D. A. Knopf. "Ice nucleation from aqueous NaCl droplets with and without marine diatoms". Atmospheric Chemistry and Physics 11, nr 12 (16.06.2011): 5539–55. http://dx.doi.org/10.5194/acp-11-5539-2011.

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Abstract. Ice formation in the atmosphere by homogeneous and heterogeneous nucleation is one of the least understood processes in cloud microphysics and climate. Here we describe our investigation of the marine environment as a potential source of atmospheric IN by experimentally observing homogeneous ice nucleation from aqueous NaCl droplets and comparing against heterogeneous ice nucleation from aqueous NaCl droplets containing intact and fragmented diatoms. Homogeneous and heterogeneous ice nucleation are studied as a function of temperature and water activity, aw. Additional analyses are presented on the dependence of diatom surface area and aqueous volume on heterogeneous freezing temperatures, ice nucleation rates, ωhet, ice nucleation rate coefficients, Jhet, and differential and cumulative ice nuclei spectra, k(T) and K(T), respectively. Homogeneous freezing temperatures and corresponding nucleation rate coefficients are in agreement with the water activity based homogeneous ice nucleation theory within experimental and predictive uncertainties. Our results confirm, as predicted by classical nucleation theory, that a stochastic interpretation can be used to describe the homogeneous ice nucleation process. Heterogeneous ice nucleation initiated by intact and fragmented diatoms can be adequately represented by a modified water activity based ice nucleation theory. A horizontal shift in water activity, Δaw, het = 0.2303, of the ice melting curve can describe median heterogeneous freezing temperatures. Individual freezing temperatures showed no dependence on available diatom surface area and aqueous volume. Determined at median diatom freezing temperatures for aw from 0.8 to 0.99, ωhet~0.11+0.06−0.05 s−1, Jhet~1.0+1.16−0.61×104 cm−2 s−1, and K~6.2+3.5−4.1 ×104 cm−2. The experimentally derived ice nucleation rates and nuclei spectra allow us to estimate ice particle production which we subsequently use for a comparison with observed ice crystal concentrations typically found in cirrus and polar marine mixed-phase clouds. Differences in application of time-dependent and time-independent analyses to predict ice particle production are discussed.

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23

P. Lamas, C., J. R. Espinosa, M. M. Conde, J. Ramírez, P. Montero de Hijes, E. G. Noya, C. Vega i E. Sanz. "Homogeneous nucleation of NaCl in supersaturated solutions". Physical Chemistry Chemical Physics 23, nr 47 (2021): 26843–52. http://dx.doi.org/10.1039/d1cp02093e.

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24

Alpert, P. A., J. Y. Aller i D. A. Knopf. "Ice nucleation from aqueous NaCl droplets with and without marine diatoms". Atmospheric Chemistry and Physics Discussions 11, nr 3 (11.03.2011): 8291–336. http://dx.doi.org/10.5194/acpd-11-8291-2011.

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Abstract. Ice formation in the atmosphere by homogeneous and heterogeneous nucleation is one of the least understood processes in cloud microphysics and climate. Here we describe our investigation of the marine environment as a potential source of atmospheric IN by experimentally observing homogeneous ice nucleation from aqueous NaCl droplets and comparing against heterogeneous ice nucleation from aqueous NaCl droplets containing intact and fragmented diatoms. Homogeneous and heterogeneous ice nucleation are studied as a function of temperature and water activity, aw. Additional analyses are presented on the dependence of diatom surface area and aqueous volume on heterogeneous freezing temperatures, ice nucleation rates, ωhet, ice nucleation rate coefficients, Jhet, and differential and cumulative ice nuclei spectra, k(T) and K(T), respectively. Homogeneous freezing temperatures and corresponding nucleation rate coefficients are in agreement with the water activity based homogeneous ice nucleation theory within experimental and predictive uncertainties. Our results confirm, as predicted by classical nucleation theory, that a stochastic interpretation can be used to describe this nucleation process. Heterogeneous ice nucleation initiated by intact and fragmented diatoms can be adequately represented by a modified water activity based ice nucleation theory. A horizontal shift in water activity, Δaw, het = 0.2303, of the ice melting curve can describe median heterogeneous freezing temperatures. Individual freezing temperatures showed no dependence on available diatom surface area and aqueous volume. Determined at median diatom freezing temperatures for aw from 0.8 to 0.99, ωhet ~ 0.11+0.06−0.05 s−1, Jhet ~ 1.0+1.16−0.61 × 104 cm−2 s−1, and K ~ 6.2+3.5−4.1 × 104 cm−2. The experimentally derived ice nucleation rates and nuclei spectra allow us to estimate ice particle production which we subsequently use for a comparison with observed ice crystal concentrations typically found in cirrus and polar marine mixed-phase clouds. Differences in application of time-dependent and time-independent analyses to predict ice particle production are discussed.

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25

Delale, Can F., Kohei Okita i Yoichiro Matsumoto. "Steady-State Cavitating Nozzle Flows With Nucleation". Journal of Fluids Engineering 127, nr 4 (2.04.2005): 770–77. http://dx.doi.org/10.1115/1.1949643.

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Quasi-one-dimensional steady-state cavitating nozzle flows with homogeneous bubble nucleation and nonlinear bubble dynamics are considered using a continuum bubbly liquid flow model. The onset of cavitation is modeled using an improved version of the classical theory of homogeneous nucleation, and the nonlinear dynamics of cavitating bubbles is described by the classical Rayleigh-Plesset equation. Using a polytropic law for the partial gas pressure within the bubble and accounting for the classical damping mechanisms, in a crude manner, by an effective viscosity, stable steady-state solutions with stationary shock waves as well as unstable flashing flow solutions were obtained, similar to the homogeneous bubbly flow solutions given by Wang and Brennen [J. Fluids Eng., 120, 166–170, 1998] and by Delale, Schnerr, and Sauer [J. Fluid Mech., 427, 167–204, 2001]. In particular, reductions in the maximum bubble radius and bubble collapse periods are observed for stable nucleating nozzle flows as compared to the nonnucleating stable solution of Wang and Brennen under similar conditions.

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26

Kwak, Ho-Young, i Sangbum Lee. "Homogeneous Bubble Nucleation Predicted by a Molecular Interaction Model". Journal of Heat Transfer 113, nr 3 (1.08.1991): 714–21. http://dx.doi.org/10.1115/1.2910622.

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The homogeneous bubble nucleation of various hydrocarbons was estimated by the modified classical nucleation theory. In this modification, the kinetic formalism of the classical theory is retained while the surface energy needed for the bubble formation is calculated from the interaction energy between molecules. With a nucleation rate value of Jnc =1022 nuclei/cm3s, this modified model gives a very good prediction of the superheat limit of liquids. In another test of the model the complete evaporation time of a butane droplet at its superheat limit is compared with experiments and found to be in good agreement.

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27

Smolík, Jiří, i Jaroslav Vítovec. "Condensation of supersaturated vapours. Homogeneous nucleation of naphthalene and phthalic anhydride". Collection of Czechoslovak Chemical Communications 50, nr 6 (1985): 1349–58. http://dx.doi.org/10.1135/cccc19851349.

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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.

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28

Ford, I. J., i C. F. Clement. "The effects of temperature fluctuations in homogeneous nucleation theory". Journal of Physics A: Mathematical and General 22, nr 18 (21.09.1989): 4007–18. http://dx.doi.org/10.1088/0305-4470/22/18/033.

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29

Girshick, Steven L. "Comment on: ‘‘Self‐consistency correction to homogeneous nucleation theory’’". Journal of Chemical Physics 94, nr 1 (styczeń 1991): 826–27. http://dx.doi.org/10.1063/1.460309.

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30

Kalikmanov, V. I., i M. E. H. van Dongen. "Cluster Approach to the Kinetic Theory of Homogeneous Nucleation". Europhysics Letters (EPL) 21, nr 6 (20.02.1993): 645–50. http://dx.doi.org/10.1209/0295-5075/21/6/002.

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31

Nadykto, Alexey B., i Fangqun Yu. "Simple correction to the classical theory of homogeneous nucleation". Journal of Chemical Physics 122, nr 10 (8.03.2005): 104511. http://dx.doi.org/10.1063/1.1861454.

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32

Ford, I. J., A. Laaksonen i M. Kulmala. "Modification of the Dillmann–Meier theory of homogeneous nucleation". Journal of Chemical Physics 99, nr 1 (lipiec 1993): 764–65. http://dx.doi.org/10.1063/1.465756.

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33

Delale, Can F., Jan Hruby i Frantisek Marsik. "Homogeneous bubble nucleation in liquids: The classical theory revisited". Journal of Chemical Physics 118, nr 2 (8.01.2003): 792–806. http://dx.doi.org/10.1063/1.1525797.

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34

McClurg, Richard B., i Richard C. Flagan. "Critical Comparison of Droplet Models in Homogeneous Nucleation Theory". Journal of Colloid and Interface Science 201, nr 2 (maj 1998): 194–99. http://dx.doi.org/10.1006/jcis.1997.5379.

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35

Goswami, Amrita, i Jayant K. Singh. "Homogeneous nucleation of sheared liquids: advances and insights from simulations and theory". Physical Chemistry Chemical Physics 23, nr 29 (2021): 15402–19. http://dx.doi.org/10.1039/d1cp02617h.

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Computational approaches for analyzing the homogeneous nucleation of sheared simple liquids are reviewed. We examine underlying mechanisms and effects of flow. The experimental scope and sheared nucleation of polymers and glasses are also covered.

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36

Sun, Cui i Zhang. "Homogeneous Nucleation Mechanism of NaCl in Aqueous Solutions". Crystals 10, nr 2 (12.02.2020): 107. http://dx.doi.org/10.3390/cryst10020107.

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In this study, molecular dynamic simulations are employed to investigate the homogeneous nucleation mechanism of NaCl crystal in solutions. According to the simulations, the dissolved behaviors of NaCl in water are dependent on ion concentrations. With increasing NaCl concentrations, the dissolved Na+ and Cl- ions tend to be aggregated in solutions. In combination with our recent studies, the aggregate of dissolved solutes is mainly ascribed to the hydrophobic interactions. Different from the two-step mechanism, no barrier is needed to overcome the formation of the aggregate. In comparison with the classical nucleation theory (CNT), because of the formation of solute aggregate, this lowers the barrier height of nucleation and affects the nucleation mechanism of NaCl crystal in water.

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37

Kubena, Josef, Alan Kubena, Ondřej Caha i Mojmir Meduna. "Homogeneous and Heterogeneous Nucleation of Oxygen in Si-CZ". Solid State Phenomena 178-179 (sierpień 2011): 495–500. http://dx.doi.org/10.4028/www.scientific.net/ssp.178-179.495.

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We present numerical simulations of nucleation kinetics of vacancies and interstitials during RTA and we study the impact of annealing temperature on bulk micro defect concentration. Since the concentration of vacancies and oxygen and also its diffusion kinetics are significantly different inside Czochralski silicon, we assume the nucleation of vacancies and oxygen independent on each other. We show that different populations of voids formed during RTA can influence formation of oxygen precipitate nuclei. According to classical nucleation theory the homogeneous nucleation dominates around temperatures 500 °C while the calculation of oxygen diffusion into the voids shows that the oxygen clusters over the critical size can be formed above temperatures 700 °C. The nuclei concentration of BMD is thus the superposition of homogeneous nucleation below 700 °C and heterogeneous one prevailing above 700 °C.

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38

Gerber, A. G. "Two-Phase Eulerian/Lagrangian Model for Nucleating Steam Flow". Journal of Fluids Engineering 124, nr 2 (28.05.2002): 465–75. http://dx.doi.org/10.1115/1.1454109.

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This paper describes an Eulerian/Lagrangian two-phase model for nucleating steam based on classical nucleation theory. The model provides an approach for including spontaneous homogeneous nucleation within a full Navier-Stokes solution scheme where the interaction between the liquid and gas phases for a pure fluid is through appropriately modeled source terms. The method allows for the straightforward inclusion of droplet heat, mass, and momentum transfer models along with nucleation within complex flow systems as found, for example, in low pressure steam turbines. The present paper describes the solution method, emphasizing that the important features of nucleating steam flow are retained through comparison with well-established 1-D solutions for Laval nozzle flows. Results for a two-dimensional cascade blade and three-dimensional low pressure turbine stage are also described.

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39

Vosel, S. V., A. A. Onischuk i P. A. Purtov. "Translation-rotation correction factor in the theory of homogeneous nucleation". Journal of Chemical Physics 131, nr 20 (28.11.2009): 204508. http://dx.doi.org/10.1063/1.3258643.

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40

Kalikmanov, V. I., i M. E. H. van Dongen. "Self-consistent cluster approach to the homogeneous kinetic nucleation theory". Physical Review E 47, nr 5 (1.05.1993): 3532–39. http://dx.doi.org/10.1103/physreve.47.3532.

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41

Laaksonen, A., I. J. Ford i M. Kulmala. "Revised parametrization of the Dillmann-Meier theory of homogeneous nucleation". Physical Review E 49, nr 6 (1.06.1994): 5517–24. http://dx.doi.org/10.1103/physreve.49.5517.

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42

Gonnermann, H. M., i J. E. Gardner. "Homogeneous bubble nucleation in rhyolitic melt: Experiments and nonclassical theory". Geochemistry, Geophysics, Geosystems 14, nr 11 (listopad 2013): 4758–73. http://dx.doi.org/10.1002/ggge.20281.

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43

Khvorostyanov, V. I., i J. A. Curry. "Parameterization of homogeneous ice nucleation for cloud and climate models based on classical nucleation theory". Atmospheric Chemistry and Physics Discussions 12, nr 3 (5.03.2012): 6745–803. http://dx.doi.org/10.5194/acpd-12-6745-2012.

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Abstract. A new analytical parameterization of homogeneous ice nucleation is developed based on extended classical nucleation theory including new equations for the critical radii of the ice germs, free energies and nucleation rates as the functions of the temperature and water saturation ratio simultaneously. By representing these quantities as separable products of the analytical functions of the temperature and supersaturation, analytical solutions are found for the integral-differential supersaturation equation and concentration of nucleated crystals. Parcel model simulations are used to illustrate the general behavior of various nucleation properties under various conditions, for justifications of the further key analytical simplifications, and for verification of the resulting parameterization. The final parameterization is based upon the values of the supersaturation that determines the current or maximum concentrations of the nucleated ice crystals. The crystal concentration is analytically expressed as a function of time and can be used for parameterization of homogeneous ice nucleation both in the models with small time steps and for substep parameterization in the models with large time steps. The crystal concentration is expressed analytically via the error functions or elementary functions and depends only on the fundamental atmospheric parameters and parameters of classical nucleation theory. The diffusion and kinetic limits of the new parameterization agree with previous semi-empirical parameterizations.

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Khvorostyanov, V. I., i J. A. Curry. "Parameterization of homogeneous ice nucleation for cloud and climate models based on classical nucleation theory". Atmospheric Chemistry and Physics 12, nr 19 (11.10.2012): 9275–302. http://dx.doi.org/10.5194/acp-12-9275-2012.

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Abstract. A new analytical parameterization of homogeneous ice nucleation is developed based on extended classical nucleation theory including new equations for the critical radii of the ice germs, free energies and nucleation rates as simultaneous functions of temperature and water saturation ratio. By representing these quantities as separable products of the analytical functions of temperature and supersaturation, analytical solutions are found for the integral-differential supersaturation equation and concentration of nucleated crystals. Parcel model simulations are used to illustrate the general behavior of various nucleation properties under various conditions, for justifications of the further key analytical simplifications, and for verification of the resulting parameterization. The final parameterization is based upon the values of the supersaturation that determines the current or maximum concentrations of the nucleated ice crystals. The crystal concentration is analytically expressed as a function of time and can be used for parameterization of homogeneous ice nucleation both in the models with small time steps and for substep parameterization in the models with large time steps. The crystal concentration is expressed analytically via the error functions or elementary functions and depends only on the fundamental atmospheric parameters and parameters of classical nucleation theory. The diffusion and kinetic limits of the new parameterization agree with previous semi-empirical parameterizations.

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Kulveit, Jan. "ISING MODEL SIMULATIONS AS A TESTBED OF NUCLEATION THEORY". Acta Polytechnica 55, nr 1 (28.02.2015): 29–33. http://dx.doi.org/10.14311/ap.2015.55.0029.

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In this short review article we discuss the use of Ising lattice model as a testbed for improvement of theory of both homogeneous and heterogeneous nucleation theory. First we briefly overview the classical nucleation theory (CNT), and two typical simple systems on which simulations are performed - hard spheres, and Ising lattice model. Than we overview some results obtained by this approach and point to possible new directions of research and improvement.

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Kaufmann, Lukas, Claudia Marcolli, Beiping Luo i Thomas Peter. "Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory". Atmospheric Chemistry and Physics 17, nr 5 (14.03.2017): 3525–52. http://dx.doi.org/10.5194/acp-17-3525-2017.

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Abstract. Homogeneous nucleation of ice in supercooled water droplets is a stochastic process. In its classical description, the growth of the ice phase requires the emergence of a critical embryo from random fluctuations of water molecules between the water bulk and ice-like clusters, which is associated with overcoming an energy barrier. For heterogeneous ice nucleation on ice-nucleating surfaces both stochastic and deterministic descriptions are in use. Deterministic (singular) descriptions are often favored because the temperature dependence of ice nucleation on a substrate usually dominates the stochastic time dependence, and the ease of representation facilitates the incorporation in climate models. Conversely, classical nucleation theory (CNT) describes heterogeneous ice nucleation as a stochastic process with a reduced energy barrier for the formation of a critical embryo in the presence of an ice-nucleating surface. The energy reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface. This study investigates various ice-nucleating agents in immersion mode by subjecting them to repeated freezing cycles to elucidate and discriminate the time and temperature dependences of heterogeneous ice nucleation. Freezing rates determined from such refreeze experiments are presented for Hoggar Mountain dust, birch pollen washing water, Arizona test dust (ATD), and also nonadecanol coatings. For the analysis of the experimental data with CNT, we assumed the same active site to be always responsible for freezing. Three different CNT-based parameterizations were used to describe rate coefficients for heterogeneous ice nucleation as a function of temperature, all leading to very similar results: for Hoggar Mountain dust, ATD, and larger nonadecanol-coated water droplets, the experimentally determined increase in freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle α as the only fit parameter. Conversely, birch pollen washing water and small nonadecanol-coated water droplets show temperature dependencies of freezing rates steeper than predicted by all three CNT parameterizations. Good agreement of observations and calculations can be obtained when a pre-factor β is introduced to the rate coefficient as a second fit parameter. Thus, the following microphysical picture emerges: heterogeneous freezing occurs at ice-nucleating sites that need a minimum (critical) surface area to host embryos of critical size to grow into a crystal. Fits based on CNT suggest that the critical active site area is in the range of 10–50 nm2, with the exact value depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle α lowers the energy barrier that has to be overcome to form the critical embryo at the site compared to the homogeneous case where the critical embryo develops in the volume of water. The pre-factor β is needed to adjust the calculated slope of freezing rate increase with temperature decrease. When this slope is steep, this can be interpreted as a high frequency of nucleation attempts, so that nucleation occurs immediately when the temperature is low enough for the active site to accommodate a critical embryo. This is the case for active sites of birch pollen washing water and for small droplets coated with nonadecanol. If the pre-factor is low, the frequency of nucleation attempts is low and the increase in freezing rate with decreasing temperature is shallow. This is the case for Hoggar Mountain dust, the large droplets coated with nonadecanol, and ATD. Various hypotheses why the value of the pre-factor depends on the nature of the active sites are discussed.

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Li, Zhi Qiang, i Jing Kun Yu. "Thermodynamic Analysis of Oxide Nucleation in Steel Cooling Process". Advanced Materials Research 282-283 (lipiec 2011): 478–82. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.478.

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Nucleating mechanism and controlling methods of Al2O3-TiO2 inclusion formed during steel cooling process is analyzed in this paper. According to the theory of nucleation, only TiO2 could satisfy the critical requirement of homogeneous nucleation to solidify stably when the temperature declines to less than 1863K. Furthermore, the generation of Al2O3 adhering on the surface of solid TiO2 is going to take place through heterogeneous nucleation, and then Al2O3 interacts with TiO2 to form Al2O3-TiO2 complex oxide. There would be no Al2O3-TiO2 complex oxide or much less Al2O3 on condition that the wTi·wO2 is less than 3.96×10-8. Both deeply deoxygenating treatments and controlling the mass of Ti-Fe alloy added into steel are effective means for improving steel quality.

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Ickes, Luisa, André Welti, Corinna Hoose i Ulrike Lohmann. "Classical nucleation theory of homogeneous freezing of water: thermodynamic and kinetic parameters". Physical Chemistry Chemical Physics 17, nr 8 (2015): 5514–37. http://dx.doi.org/10.1039/c4cp04184d.

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ZHONG, JING, ZHI-GANG CHEN, JUN-MIN LIAO, MING-SHIUAN TANG, CHENG-BIN CHEN i CHENG-LUNG CHEN. "STUDY ON HOMOGENEOUS PRECIPITATION OF CeO2 NANOPARTICLES BY DISSIPATIVE PARTICLE DYNAMICS SIMULATION". Journal of Theoretical and Computational Chemistry 08, nr 03 (czerwiec 2009): 459–73. http://dx.doi.org/10.1142/s021963360900485x.

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Dissipative particle dynamics (DPD) was carried out to study the nucleation and crystal growth process of cerium dioxide ( CeO 2) nanoparticles in alcohol/water mixed solvents by homogeneous precipitation method. The results showed that properly selecting the sizes of CeO 2 and water beads, and choosing the appropriate interaction parameters between beads are crucial in the simulation system. The nucleation and crystal growth process of CeO 2 can be classified into four stages: induction, nuclei growth, crystal forming, and crystal aggregation, which could be reproduced from different initial CeO 2 concentration and after different simulation time. The simulation results confirm that the effect of solvent on the nucleation and crystal growth of CeO 2 nanoparticles are different at four stages and cannot be simply described by Derjaguin–Landau–Verwey–Overbeek theory or nucleation thermodynamics theory as proposed in the published literatures. Our work demonstrated that DPD methods can be applied to study nanoparticle forming process.

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Möhler, O., H. Bunz i O. Stetzer. "Homogeneous nucleation rates of nitric acid dihydrate (NAD) at simulated stratospheric conditions – Part II: Modelling". Atmospheric Chemistry and Physics Discussions 6, nr 2 (28.03.2006): 2119–49. http://dx.doi.org/10.5194/acpd-6-2119-2006.

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Abstract. Activation energies ΔGact for the nucleation of nitric acid dihydrate (NAD) in supercooled binary HNO3/H2O solution droplets were calculated from volume-based nucleation rate measurements using the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) aerosol chamber of Forschungszentrum Karlsruhe. The experimental conditions covered temperatures T between 192 K and 197 K, NAD saturation ratios SNAD between 7 and 10, and nitric acid molar fractions of the nucleating sub-micron sized droplets between 0.26 and 0.28. Based on classical nucleation theory, a new parameterisation ΔGact=A×(T lnSNAD)-2+B is fitted to our experimetnal data with A=2.5×106 kcal K2 mol-1 and B=11.2−0.1(T−192) kcal mol-1. A and B were chosen to also achieve good agreement with literature data of ΔGact. The parameter A implies a constant interfacial tension σsl=51 cal mol-1 cm-2 between the growing NAD germ and the supercooled solution. A slight temperature dependence of the diffusion activation energy is represented by the parameter B. Investigations with a detailed microphysical process model showed that literature formulations of volume-based (Salcedo et al., 2001) and surface-based (Tabazadeh et al., 2002) nucleation rates significantly overestimate NAD formation rates when applied to the conditions of our experiments.

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