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Готові списки джерел за темами / Coagulation and condensation structures / Статті в журналах

Статті в журналах з теми "Coagulation and condensation structures"

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Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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1

Kärcher, B. "Simulating gas-aerosol-cirrus interactions: Process-oriented microphysical model and applications." Atmospheric Chemistry and Physics Discussions 3, no. 4 (July 29, 2003): 4129–81. http://dx.doi.org/10.5194/acpd-3-4129-2003.

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Abstract. This work describes a process-oriented, microphysical-chemical model to simulate the formation and evolution of aerosols and ice crystals under the conditions prevailing in the upper troposphere and lower stratosphere. The model can be run as a box model or along atmospheric trajectories, and considers mixing, gas phase chemistry of aerosol precursors, binary homogeneous aerosol nucleation, homogeneous and heterogeneous ice nucleation, coagulation, condensation and dissolution, gas retention during particle freezing, gas trapping in growing ice crystals, and reverse processes. Chemical equations are solved iteratively using a second order implicit integration method. Gas-particle interactions and coagulation are treated over various size structures, with fully mass conserving and non-iterative numerical solution schemes. Particle types include quinternary aqueous solutions composed of H2SO4, HNO3, HCl, and HBr with and without insoluble components, insoluble aerosol particles, and spherical or columnar ice crystals deriving from each aerosol type separately. Three case studies are discussed in detail to demonstrate the potential of the model to simulate real atmospheric processes and to highlight current research topics concerning aerosol and cirrus formation near the tropopause. Emphasis is placed on how the formation of cirrus clouds and the scavenging on nitric acid in cirrus depends on small-scale temperature fluctuations and the presence of efficient ice nuclei in the tropopause region, corroborating and partly extending the findings of previous studies.

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2

Kärcher, B. "Simulating gas-aerosol-cirrus interactions: Process-oriented microphysical model and applications." Atmospheric Chemistry and Physics 3, no. 5 (October 7, 2003): 1645–64. http://dx.doi.org/10.5194/acp-3-1645-2003.

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Abstract. This work describes a process-oriented, microphysical-chemical model to simulate the formation and evolution of aerosols and ice crystals under the conditions prevailing in the upper troposphere and lower stratosphere. The model can be run as a box model or along atmospheric trajectories, and considers mixing, gas phase chemistry of aerosol precursors, binary homogeneous aerosol nucleation, homogeneous and heterogeneous ice nucleation, coagulation, condensation and dissolution, gas retention during particle freezing, gas trapping in growing ice crystals, and reverse processes. Chemical equations are solved iteratively using a second order implicit integration method. Gas-particle interactions and coagulation are treated over various size structures, with fully mass conserving and non-iterative numerical solution schemes. Particle types include quinternary aqueous solutions composed of H2SO4, HNO3, HCl, and HBr with and without insoluble components, insoluble aerosol particles, and spherical or columnar ice crystals deriving from each aerosol type separately. Three case studies are discussed in detail to demonstrate the potential of the model to simulate real atmospheric processes and to highlight current research topics concerning aerosol and cirrus formation near the tropopause. Emphasis is placed on how the formation of cirrus clouds and the scavenging of nitric acid in cirrus depends on small-scale temperature fluctuations and the presence of efficient ice nuclei in the tropopause region, corroborating and partly extending the findings of previous studies.

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3

Owen, James E. "Snow lines can be thermally unstable." Monthly Notices of the Royal Astronomical Society 495, no. 3 (January 2020): 3160–74. http://dx.doi.org/10.1093/mnras/staa1309.

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ABSTRACT Volatile species in protoplanetary discs can undergo a phase change from vapour to solid. These ‘snow lines’ can play vital roles in planet formation at all scales, from dust coagulation to planetary migration. In the outer regions of protoplanetary discs, the temperature profile is set by the absorption of reprocessed stellar light by the solids. Further, the temperature profile sets the distribution of solids through sublimation and condensation at various snow lines. Hence, the snow line position depends on the temperature profile and vice versa. We show that this coupling can be thermally unstable, such that a patch of the disc at a snow line will produce either runaway sublimation or condensation. This thermal instability arises at moderate optical depths, where heating by absorption of reprocessed stellar light from the disc’s atmosphere is optically thick, yet cooling is optically thin. Since volatiles in the solid phase drift much faster than volatiles in the vapour phase, this thermal instability results in a limit cycle. The snow line progressively moves in, condensing volatiles, before receding, as the volatiles sublimate. Using numerical simulations, we study the evolution of the carbon monoxide (CO) snow line. We find the CO snow line is thermally unstable under typical disc conditions and evolves inwards from ∼50 to ∼30 au on time-scales from 1000 to 10 000 yr. The CO snow line spends between ${\sim}10{{\ \rm per\ cent}}\,\mathrm{ and}\,50{{\ \rm per\ cent}}$ of its time at smaller separations, where the exact value is sensitive to the total opacity and turbulent viscosity. The evolving snow line also creates ring-like structures in the solid distribution interior to the snow line. Multiple ring-like structures created by moving snow lines could potentially explain the substructures seen in many ALMA images.

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4

Adachi, K., and P. R. Buseck. "Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City." Atmospheric Chemistry and Physics 8, no. 21 (November 13, 2008): 6469–81. http://dx.doi.org/10.5194/acp-8-6469-2008.

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Abstract. Soot particles, which are aggregated carbonaceous spherules with graphitic structures, are major aerosol constituents that result from burning of fossil fuel, biofuel, and biomass. Their properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using a transmission electron microscope (TEM) for both imaging and chemical analysis, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. Most particles are coated, consist of aggregates, or both. For example, almost all analyzed particles contain S and 70% also contain K, suggesting coagulation and condensation of sulfates and particles derived from biomass and biofuel burning. In the MC plumes, over half of all particles contained soot coated by organic matter and sulfates. The median value of the soot volume fraction in such coated particles is about 15%. In contrast to the assumptions used in many climate models, the soot particles did not become compact even when coated. Moreover, about 80% by volume of the particles consisting of organic matter with sulfate also contained soot, indicating the important role of soot in the formation of secondary aerosol particles. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetimes. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate of MC than uncoated soot particles.

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5

Korneyeva, E. V., G. I. Berdov, and S. A. Sozinov. "FEATURES OF THE FORMATION OF THE STRUCTURE OF A CEMENTLESS MATRIX COMPOSITE BASED ON MECHANICALLY ACTIVATED TECHNOGENIC RAW MATERIALS." Construction and Geotechnics 11, no. 1 (December 15, 2020): 102–14. http://dx.doi.org/10.15593/2224-9826/2020.1.10.

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The creation of composite materials using mechanically activated technogenic raw materials is relevant today as part of a large-scale task of construction and technological utilization of technogenic formations. The change in the crystal structure using mechanochemistry increases the activity of technogenic products: the number of coagulation contacts of dissimilar particles increases, increases the plastic strength of the hardening mixture, formation of hydration products is accelerated. The article is devoted to the study of the mechanism of structural and rheological transformations of a cementless hardening system based on activated steelmaking. Steel melting slags were used as raw materials - energy-saturated large-capacity waste of the West-Siberian Metallurgical Combine (Novokuznetsk). As components - activators - waste from the coal industry of the «Abashevskaya» mine (Novokuznetsk) - burnt rocks with heaps and slimes, obtained by neutralization of spent acid battery electrolytes with lime batteries for industrial vehicles. Based on used mechanically activated technogenic raw materials the binder composite material of the matrix structure is obtained. To assess structural and material changes in the hardening system comprehensive physical and chemical studies were carried out: IR - spectroscopy, thermogravimetric and x-ray phase analysis. Electron microscopy investigated the structure of the stone. It was found that the matrix structure of the composite material is a dispersion medium - matrix of dense fine-grained masses calcium sulfate hydrate; dispersed phase from lamellar crystals of quartz and magnesium oxide, and tubular crystals of calcium orthosilicate; and transitional interfacial layer from structured grains of calcium hydrosulfoaluminate. In the process of forming the structure interdependence of phases from each other was accompanied by a sequential transition of some types of structures to others: coagulation→ crystallization- condensation→ crystallization. The article presents the results of the self-organization of the structure, the interaction of oxide systems in the process of hydration is considered, major mineral neoplasms are established, possessing astringent properties and providing strong bonds between structure-forming components.

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6

Курбатов, Vladimir Kurbatov, Комарова, and Natalya Komarova. "DISPERSE RAW MIXES, THEIR FEATURES OF CAPILLARY STRUCTURIZATION." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 2, no. 1 (December 8, 2016): 33–36. http://dx.doi.org/10.12737/24087.

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In space and in time the structure of any material continuously undergoes changes, to it, in particular, the constant movement of elementary particles, atoms, molecules, interaction of material with the environment promote. For example, almost all construction materials and their raw mixes, at least, at the microlevel, represent the microheterogeneous disperse systems consisting several phases to which number the liquid component belongs. The nature of structure of such systems in many respects is de-fined by character and size of communications or forces of adhesion between structural elements (microparticles, grains, etc.). Depending on the nature of these communications in disperse systems allocate strong phase contacts in condensation or crystallizational structures of disperse materials, direct atomic contacts in dry powders and rather weak forces of molecular interaction operating between particles through layers of a liquid phase in coagulative structures. Besides the types of interactions and the relevant structures considered above it is necessary to allocate such important interactions as capillary, shown in three-phase (firm - liquid - gas) disperse systems to which the majority raw (concrete, the rastvornykh, silicate, etc.) mixes for production of construction composite materials belongs, for example.

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7

Lushnikov, A. A., and M. Kulmala. "New selfpreserving regimes of coagulation-condensation." Journal of Aerosol Science 32 (September 2001): 981–92. http://dx.doi.org/10.1016/s0021-8502(01)00138-0.

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8

Maetzing, H., W. Baumann, and H. R. Paur. "Bimodal aerosol coagulation with simultaneous condensation/evaporation." Journal of Aerosol Science 27 (September 1996): S363—S364. http://dx.doi.org/10.1016/0021-8502(96)00254-6.

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9

Sinaiskii, �. G., and V. N. Men'shov. "Drop condensation and coagulation during gas throttling." Journal of Engineering Physics 52, no. 1 (January 1987): 13–17. http://dx.doi.org/10.1007/bf00870194.

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10

Garrick, Sean C. "Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows." Journal of Nanotechnology 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/642014.

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Titanium dioxide (titania) is used in chemical sensors, pigments, and paints and holds promise as an antimicrobial agent. This is due to its photoinduced activity and, in nanostructured form, its high specific surface area. Particle size and surface area result from the interplay of fluid, chemical, and thermal dynamics as well as nucleation, condensation and coagulation. After nucleation, condensation, and coagulation are the dominant phenomena affecting the particle size distribution. Manufacture of nanostructured titania via gas-phase synthesis often occurs under turbulent flow conditions. This study examines the competition between coagulation and condensation in the growth of nanostructured titania. Direct numerical simulation is utilized in simulating the hydrolysis of titanium tetrachloride to produce titania in a turbulent, planar jet. The fluid, chemical, and particle fields are resolved as a function of space and time. As a result, knowledge of titania is available as a function of space, time, and phase (vapor or particle), facilitating the analysis of the particle dynamics by mechanism. Results show that in the proximal region of the jet nucleation and condensation are the dominant mechanisms. However once the jet potential core collapses and turbulent mixing begins, coagulation is the dominant mechanism. The data also shows that the coagulation growth-rate is as much as twice the condensation growth-rate.

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11

Sterzik, Michael F., and Gregor E. Morfill. "Evolution of Protoplanetary Disks with Condensation and Coagulation." Icarus 111, no. 2 (October 1994): 536–46. http://dx.doi.org/10.1006/icar.1994.1162.

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12

Pratsinis, Sotiris E. "Simultaneous nucleation, condensation, and coagulation in aerosol reactors." Journal of Colloid and Interface Science 124, no. 2 (August 1988): 416–27. http://dx.doi.org/10.1016/0021-9797(88)90180-4.

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13

Liu, Hongmei, Jingping Shao, Wei Jiang, and Xuedong Liu. "Numerical Modeling of Droplet Aerosol Coagulation, Condensation/Evaporation and Deposition Processes." Atmosphere 13, no. 2 (February 15, 2022): 326. http://dx.doi.org/10.3390/atmos13020326.

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The differentially weighted operator-splitting Monte Carlo (DWOSMC) method is further developed to describe the droplet aerosol dynamic behaviors, including coagulation, deposition, condensation, and evaporation processes. It is first proposed that the droplet aerosols will experience firstly condensation and then evaporation, and this phenomenon is first implemented into the Monte Carlo method and sectional method with considering coagulation, deposition, and condensation/evaporation processes in both single-component and two-component aerosol particle systems. It is found that the calculated results of the DWOSMC method agree well with both the analytical solutions and the sectional method. The further developed DWOSMC method can predict the variation of particle number density, total particle volume, mean particle diameter, particle size distributions, and the component-related particle volume densities in both single component and two-component droplet aerosol systems considering coagulation, deposition, and condensation/evaporation processes.

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14

Cai, Runlong, Chenxi Li, Xu-Cheng He, Chenjuan Deng, Yiqun Lu, Rujing Yin, Chao Yan, et al. "Impacts of coagulation on the appearance time method for new particle growth rate evaluation and their corrections." Atmospheric Chemistry and Physics 21, no. 3 (February 16, 2021): 2287–304. http://dx.doi.org/10.5194/acp-21-2287-2021.

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Abstract. The growth rate of atmospheric new particles is a key parameter that determines their survival probability of becoming cloud condensation nuclei and hence their impact on the climate. There have been several methods to estimate the new particle growth rate. However, due to the impact of coagulation and measurement uncertainties, it is still challenging to estimate the initial growth rate of new particles, especially in polluted environments with high background aerosol concentrations. In this study, we explore the influences of coagulation on the appearance time method to estimate the growth rate of sub-3 nm particles. The principle of the appearance time method and the impacts of coagulation on the retrieved growth rate are clarified via derivations. New formulae in both discrete and continuous spaces are proposed to correct for the impacts of coagulation. Aerosol dynamic models are used to test the new formulae. New particle formation in urban Beijing is used to illustrate the importance of considering the impacts of coagulation on the sub-3 nm particle growth rate and its calculation. We show that the conventional appearance time method needs to be corrected when the impacts of coagulation sink, coagulation source, and particle coagulation growth are non-negligible compared to the condensation growth. Under the simulation conditions with a constant concentration of non-volatile vapors, the corrected growth rate agrees with the theoretical growth rates. However, the uncorrected parameters, e.g., vapor evaporation and the variation in vapor concentration, may impact the growth rate obtained with the appearance time method. Under the simulation conditions with a varying vapor concentration, the average bias in the corrected 1.5–3 nm particle growth rate ranges from 6 %–44 %, and the maximum bias in the size-dependent growth rate is 150 %. During the test new particle formation event in urban Beijing, the corrected condensation growth rate of sub-3 nm particles was in accordance with the growth rate contributed by sulfuric acid condensation, whereas the conventional appearance time method overestimated the condensation growth rate of 1.5 nm particles by 80 %.

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15

KELLER, A., and H. C. SIEGMANN. "The role of condensation and coagulation in aerosol monitoring." Journal of Exposure Science & Environmental Epidemiology 11, no. 6 (December 2001): 441–48. http://dx.doi.org/10.1038/sj.jea.7500187.

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16

Davis, Sheldon B., Thomas K. Gale, Jost O. L. Wendt, and William P. Linak. "Multicomponent coagulation and condensation of toxic metals in combustors." Symposium (International) on Combustion 27, no. 2 (January 1998): 1785–91. http://dx.doi.org/10.1016/s0082-0784(98)80020-9.

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17

Priya P., Meena, and Nirmala P. Ratchagar. "Coagulation and Condensation of Aerosols in Atmospheric Dispersion Model." Journal of Computational Multiphase Flows 5, no. 2 (June 2013): 115–38. http://dx.doi.org/10.1260/1757-482x.5.2.115.

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18

Palaniswaamy, Geethpriya, and Sudarshan K. Loyalka. "Direct simulation, Monte Carlo, aerosol dynamics: Coagulation and condensation." Annals of Nuclear Energy 35, no. 3 (March 2008): 485–94. http://dx.doi.org/10.1016/j.anucene.2007.06.024.

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19

Liu, Li Ping, Guo Dong Song, and Lei Yu. "The Research Progress of Coagulation Technology on Fine Particles." Applied Mechanics and Materials 723 (January 2015): 715–18. http://dx.doi.org/10.4028/www.scientific.net/amm.723.715.

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This article reviewed some of the measures taken to control particulate matters by combining the latest fine particles dominating technologies both at home and abroad. The coagulation technological principles and research achievements of fine particles were suggested. The research highlightly analyzed the technical principles and characteristics of electric coagulation technology, acoustic coagulation technology, vapor condensation technology, thermal coagulation technology,chemical coagulation technology, magnetic coagulation technology, turbulent coagulation technology and light coagulation technology.On the basis of comprehensive analysis of these technologies, it pointed out the development trend of fine particle control technology.

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20

He, C., Q. Li, K. N. Liou, L. Qi, S. Tao, and J. P. Schwarz. "Microphysics-based black carbon aging in a global CTM: constraints from HIPPO observations and implications for global black carbon budget." Atmospheric Chemistry and Physics Discussions 15, no. 22 (November 20, 2015): 32779–829. http://dx.doi.org/10.5194/acpd-15-32779-2015.

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Abstract. We develop and examine a microphysics-based black carbon (BC) aerosol aging scheme that accounts for condensation and coagulation processes in a global 3-D chemical transport model (GEOS-Chem) by interpreting the BC measurements from the HIAPER Pole-to-Pole Observations (HIPPO, 2009–2011) using the model. We convert aerosol mass in the model to number concentration by assuming lognormal aerosol size distributions and compute the microphysical BC aging rate explicitly from the condensation of soluble materials onto hydrophobic BC and the coagulation between hydrophobic BC and preexisting soluble particles. The resulting aging rate is ∼ 4 times higher in the lower troposphere over source regions than that from a fixed aging scheme with an e-folding time of 1.2 days. The higher aging rate reflects the large emissions of sulfate-nitrate and secondary organic aerosol precursors hence faster BC aging through condensation and coagulation. In contrast, the microphysical aging is more than fivefold slower than the fixed aging in remote regions, where condensation and coagulation are weak. Globally BC microphysical aging is dominated by condensation, while coagulation contribution is largest over East China, India, and Central Africa. The fixed aging scheme results in an overestimate of HIPPO BC throughout the troposphere by a factor of 6 on average. The microphysical scheme reduces this discrepancy by a factor of ∼ 3, particularly in the middle and upper troposphere. It also leads to a threefold reduction in model bias in the latitudinal BC column burden averaged along the HIPPO flight tracks, with largest improvements in the tropics. The resulting global annual mean BC lifetime is 4.2 days and BC burden is 0.25 mg m-2, with 7.3 % of the burden at high altitudes (above 5 km). Wet scavenging accounts for 80.3 % of global BC deposition. We find that in source regions the microphysical aging rate is insensitive to aerosol size distribution, condensation threshold, and chemical oxidation aging, while it is the opposite in remote regions, where the aging rate is orders of magnitude smaller. As a result, global BC burden and lifetime show little sensitivity (< 5 % change) to these three factors.

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21

He, Cenlin, Qinbin Li, Kuo-Nan Liou, Ling Qi, Shu Tao, and Joshua P. Schwarz. "Microphysics-based black carbon aging in a global CTM: constraints from HIPPO observations and implications for global black carbon budget." Atmospheric Chemistry and Physics 16, no. 5 (March 9, 2016): 3077–98. http://dx.doi.org/10.5194/acp-16-3077-2016.

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Abstract. We develop and examine a microphysics-based black carbon (BC) aerosol aging scheme that accounts for condensation, coagulation, and heterogeneous chemical oxidation processes in a global 3-D chemical transport model (GEOS-Chem) by interpreting the BC measurements from the HIAPER Pole-to-Pole Observations (HIPPO, 2009–2011) using the model. We convert aerosol mass in the model to number concentration by assuming lognormal aerosol size distributions and compute the microphysical BC aging rate (excluding chemical oxidation aging) explicitly from the condensation of soluble materials onto hydrophobic BC and the coagulation between hydrophobic BC and preexisting soluble particles. The chemical oxidation aging is tested in the sensitivity simulation. The microphysical aging rate is ∼ 4 times higher in the lower troposphere over source regions than that from a fixed aging scheme with an e-folding time of 1.2 days. The higher aging rate reflects the large emissions of sulfate–nitrate and secondary organic aerosol precursors hence faster BC aging through condensation and coagulation. In contrast, the microphysical aging is more than 5-fold slower than the fixed aging in remote regions, where condensation and coagulation are weak. Globally, BC microphysical aging is dominated by condensation, while coagulation contribution is largest over eastern China, India, and central Africa. The fixed aging scheme results in an overestimate of HIPPO BC throughout the troposphere by a factor of 6 on average. The microphysical scheme reduces this discrepancy by a factor of ∼ 3, particularly in the middle and upper troposphere. It also leads to a 3-fold reduction in model bias in the latitudinal BC column burden averaged along the HIPPO flight tracks, with largest improvements in the tropics. The resulting global annual mean BC lifetime is 4.2 days and BC burden is 0.25 mg m−2, with 7.3 % of the burden at high altitudes (above 5 km). Wet scavenging accounts for 80.3 % of global BC deposition. We find that, in source regions, the microphysical aging rate is insensitive to aerosol size distribution, condensation threshold, and chemical oxidation aging, while it is the opposite in remote regions, where the aging rate is orders of magnitude smaller. As a result, global BC burden and lifetime show little sensitivity (< 5 % change) to these three factors.

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22

Bache, D. H., C. Johnson, E. Papavasilopoulos, E. Rasool, and F. J. McGilligan. "Sweep coagulation: structures, mechanisms and practice." Journal of Water Supply: Research and Technology-Aqua 48, no. 5 (September 1999): 201–10. http://dx.doi.org/10.2166/aqua.1999.0022.

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23

Nishimura, Tamiki, Makoto Sunagawa, Toshiya Okajima, and Yoshimasa Fukazawa. "Transition structures for the dieckmann condensation." Tetrahedron Letters 38, no. 40 (October 1997): 7063–66. http://dx.doi.org/10.1016/s0040-4039(97)01649-3.

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24

Riley, Brian J., Bradley R. Johnson, H. Todd Schaef, and Shanmugavelayutham K. Sundaram. "Sublimation–Condensation of Multiscale Tellurium Structures." Journal of Physical Chemistry C 117, no. 19 (May 3, 2013): 10128–34. http://dx.doi.org/10.1021/jp400363a.

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25

Jung, Chang H., Ji Yi Lee, and Yong P. Kim. "Changes in the Ångstrom Exponent during Aerosol Coagulation and Condensation." Asian Journal of Atmospheric Environment 6, no. 4 (December 1, 2012): 304–13. http://dx.doi.org/10.5572/ajae.2012.6.4.304.

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26

Piskunov, Vladimir N. "Analytical solutions for coagulation and condensation kinetics of composite particles." Physica D: Nonlinear Phenomena 249 (April 2013): 38–45. http://dx.doi.org/10.1016/j.physd.2013.01.008.

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27

Smith, Naftali R., Nir J. Shaviv, and Henrik Svensmark. "Approximate analytical solutions to the condensation-coagulation equation of aerosols." Aerosol Science and Technology 50, no. 6 (March 30, 2016): 578–90. http://dx.doi.org/10.1080/02786826.2016.1168921.

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28

Zhu, S., K. N. Sartelet, and C. Seigneur. "A size-composition resolved aerosol model for simulating the dynamics of externally mixed particles: SCRAM (v 1.0)." Geoscientific Model Development 8, no. 6 (June 1, 2015): 1595–612. http://dx.doi.org/10.5194/gmd-8-1595-2015.

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Abstract. The Size-Composition Resolved Aerosol Model (SCRAM) for simulating the dynamics of externally mixed atmospheric particles is presented. This new model classifies aerosols by both composition and size, based on a comprehensive combination of all chemical species and their mass-fraction sections. All three main processes involved in aerosol dynamics (coagulation, condensation/evaporation and nucleation) are included. The model is first validated by comparison with a reference solution and with results of simulations using internally mixed particles. The degree of mixing of particles is investigated in a box model simulation using data representative of air pollution in Greater Paris. The relative influence on the mixing state of the different aerosol processes (condensation/evaporation, coagulation) and of the algorithm used to model condensation/evaporation (bulk equilibrium, dynamic) is studied.

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29

Fierce, L., N. Riemer, and T. Bond. "Explaining variance in black carbon's aging timescale." Atmospheric Chemistry and Physics Discussions 14, no. 13 (July 16, 2014): 18703–37. http://dx.doi.org/10.5194/acpd-14-18703-2014.

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Abstract. The size and composition of particles containing black carbon (BC) are modified soon after emission by condensation of semi-volatile substances and coagulation with other particles, known collectively as "aging" processes. Although this change in particle properties is widely recognized, the timescale for transformation is not well constrained. In this work, we simulated aerosol aging with the particle-resolved model PartMC-MOSAIC and extracted aging timescales based on changes in particle cloud condensation nuclei (CCN). We simulated nearly 300 scenarios and, through a regression analysis, identified the key parameters driving the value of the aging timescale. We show that BC's aging timescale spans from hours to weeks, depending on the local environmental conditions and the characteristics of the fresh BC-containing particles. Although the simulations presented in this study included many processes and particle interactions, we show that 80% of the variance in the aging timescale is explained by only a few key parameters. The condensation aging timescale decreased with the flux of condensing aerosol and was shortest for the largest fresh particles, while the coagulation aging timescale decreased with the total number concentration of large (D > 100 nm), CCN-active particles and was shortest for the smallest fresh particles. Therefore, both condensation and coagulation play important roles in aging, and their relative impact depends on the particle size range.

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30

Fierce, L., N. Riemer, and T. C. Bond. "Explaining variance in black carbon's aging timescale." Atmospheric Chemistry and Physics 15, no. 6 (March 20, 2015): 3173–91. http://dx.doi.org/10.5194/acp-15-3173-2015.

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Abstract. The size and composition of particles containing black carbon (BC) are modified soon after emission by condensation of semivolatile substances and coagulation with other particles, known collectively as "aging" processes. Although this change in particle properties is widely recognized, the timescale for transformation is not well constrained. In this work, we simulated aerosol aging with the particle-resolved model PartMC-MOSAIC (Particle Monte Carlo – Model for Simulating Aerosol Interactions and Chemistry) and extracted aging timescales based on changes in particle cloud condensation nuclei (CCN). We simulated nearly 300 scenarios and, through a regression analysis, identified the key parameters driving the value of the aging timescale. We show that BC's aging timescale spans from hours to weeks, depending on the local environmental conditions and the characteristics of the fresh BC-containing particles. Although the simulations presented in this study included many processes and particle interactions, we show that 80% of the variance in the aging timescale is explained by only a few key parameters. The condensation aging timescale decreased with the flux of condensing aerosol and was shortest for the largest fresh particles, while the coagulation aging timescale decreased with the total number concentration of large (D >100 nm), CCN-active particles and was shortest for the smallest fresh particles. Therefore, both condensation and coagulation play important roles in aging, and their relative impact depends on the particle size range.

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31

Tian, J., N. Riemer, M. West, L. Pfaffenberger, H. Schlager, and A. Petzold. "Modeling the evolution of aerosol particles in a ship plume using PartMC-MOSAIC." Atmospheric Chemistry and Physics 14, no. 11 (June 3, 2014): 5327–47. http://dx.doi.org/10.5194/acp-14-5327-2014.

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Abstract. This study investigates the evolution of ship-emitted aerosol particles using the stochastic particle-resolved model PartMC-MOSAIC (Particle Monte Carlo model-Model for Simulating Aerosol Interactions and Chemistry). Comparisons of our results with observations from the QUANTIFY (Quantifying the Climate Impact of Global and European Transport Systems) study in 2007 in the English Channel and the Gulf of Biscay showed that the model was able to reproduce the observed evolution of total number concentration and the vanishing of the nucleation mode consisting of sulfate particles. Further process analysis revealed that during the first hour after emission, dilution reduced the total number concentration by four orders of magnitude, while coagulation reduced it by an additional order of magnitude. Neglecting coagulation resulted in an overprediction of more than one order of magnitude in the number concentration of particles smaller than 40 nm at a plume age of 100 s. Coagulation also significantly altered the mixing state of the particles, leading to a continuum of internal mixtures of sulfate and black carbon. The impact on cloud condensation nuclei (CCN) concentrations depended on the supersaturation threshold S at which CCN activity was evaluated. For the base case conditions, characterized by a low formation rate of secondary aerosol species, neglecting coagulation, but simulating condensation, led to an underestimation of CCN concentrations of about 37% for S = 0.3% at the end of the 14-h simulation. In contrast, for supersaturations higher than 0.7%, neglecting coagulation resulted in an overestimation of CCN concentration, about 75% for S = 1%. For S lower than 0.2% the differences between simulations including coagulation and neglecting coagulation were negligible. Neglecting condensation, but simulating coagulation did not impact the CCN concentrations below 0.2% and resulted in an underestimation of CCN concentrations for larger supersaturations, e.g., 18% for S = 0.6%. We also explored the role of nucleation for the CCN concentrations in the ship plume. For the base case the impact of nucleation on CCN concentrations was limited, but for a sensitivity case with higher formation rates of secondary aerosol over several hours, the CCN concentrations increased by an order of magnitude for supersaturation thresholds above 0.3%.

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32

Sun, Z., R. Axelbaum, and J. Huertas. "Monte Carlo Simulation of Multicomponent Aerosols Undergoing Simultaneous Coagulation and Condensation." Aerosol Science and Technology 38, no. 10 (October 2004): 963–71. http://dx.doi.org/10.1080/027868290513847.

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33

KURILIĆ, MILOŠ S. "RETRACTIONS OF REVERSIBLE STRUCTURES." Journal of Symbolic Logic 82, no. 4 (December 2017): 1422–37. http://dx.doi.org/10.1017/jsl.2017.60.

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AbstractA relational structure is called reversible iff each bijective endomorphism (condensation) of that structure is an automorphism. We show that reversibility is an invariant of some forms of L∞ω −bi-interpretability, implying that the condensation monoids of structures are topologically isomorphic. Applying these results, we prove that, in particular, all orbits of ultrahomogeneous tournaments and reversible ultrahomogeneous m-uniform hypergraphs are reversible relations and that the same holds for the orbits of reversible ultrahomogeneous digraphs definable by formulas which are not R-negative.

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34

Ros, Katrin. "Ice Condensation as a Planet Formation Mechanism." Proceedings of the International Astronomical Union 8, S299 (June 2013): 382–83. http://dx.doi.org/10.1017/s1743921313009022.

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AbstractParticles in protoplanetary discs grow rapidly to millimetre-sizes via coagulation, but further growth to centimetre-sized pebbles is not yet completely understood. We investigate particle growth by ice condensation in a model where we take the dynamical behaviour of vapour and ice particles into account, as well as the size evolution due to condensation and sublimation. Our results show that efficient growth from dust to pebbles is possible close to the water ice line at ~3 AU, with particles growing from millimetres to decimetres on a time scale of 10000 yr.

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35

Rivera, Mario A., Mahendra P. Singh, and Luis E. Suarez. "Dynamic Condensation Approach for Nonclassically Damped Structures." AIAA Journal 37, no. 5 (May 1999): 564–71. http://dx.doi.org/10.2514/2.774.

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36

Cai, Steve Q., and Avijit Bhunia. "Superhydrophobic Condensation Enhanced by Conical Hierarchical Structures." Journal of Physical Chemistry C 121, no. 18 (April 27, 2017): 10047–52. http://dx.doi.org/10.1021/acs.jpcc.7b02554.

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37

de la Rosa, J. C., A. Escrivá, L. E. Herranz, T. Cicero, and J. L. Muñoz-Cobo. "Review on condensation on the containment structures." Progress in Nuclear Energy 51, no. 1 (January 2009): 32–66. http://dx.doi.org/10.1016/j.pnucene.2008.01.003.

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38

Rivera, Mario A., Luis E. Suarez, and Mahendra P. Singh. "Dynamic condensation approach for nonclassically damped structures." AIAA Journal 37 (January 1999): 564–71. http://dx.doi.org/10.2514/3.14210.

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39

Meakin, Paul, and J. M. Deutch. "Fractal structures from an evaporation/condensation model." Journal of Chemical Physics 83, no. 8 (October 15, 1985): 4086–92. http://dx.doi.org/10.1063/1.449073.

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40

Bohdal, Tadeusz, Małgorzata Sikora, Katarzyna Widomska, and Andrii M. Radchenko. "Investigation of flow structures during HFE-7100 refrigerant condensation." Archives of Thermodynamics 36, no. 4 (December 1, 2015): 25–34. http://dx.doi.org/10.1515/aoter-2015-0030.

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Abstract The experimental research of environmentally friendly refrigerant HFE-7100 condensation in pipe minichannels was conducted. During the investigations of HFE-7100 condensation in a minichannel with internal diameter 2 mm together with visualization of flow patterns was made. Visualization results were compared with existing flow structure maps. The identification of the range of flow patterns occurrence during the condensation process of low-pressure refrigerant HFE-7100 was made. The tests were performed throughout the whole range of condensation process.

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41

Buvaylo, Elena A., Vladimir N. Kokozay, Nataliia Yu Strutynska, Olga Yu Vassilyeva, and Brian W. Skelton. "Formaldehyde–aminoguanidine condensation and aminoguanidine self-condensation products: syntheses, crystal structures and characterization." Acta Crystallographica Section C Structural Chemistry 74, no. 2 (January 12, 2018): 152–58. http://dx.doi.org/10.1107/s2053229617018514.

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Guanidine is the functional group on the side chain of arginine, one of the fundamental building blocks of life. In recent years, a number of compounds based on the aminoguanidine (AG) moiety have been described as presenting high anticancer activities. The product of condensation between two molecules of AG and one molecule of formaldehyde was isolated in the protonated form as the dinitrate salt (systematic name: 2,8-diamino-1,3,4,6,7,9-hexaazanona-1,8-diene-1,9-diium dinitrate), C3H14N8 2+·2NO3 −, (I). The cation lacks crystallographically imposed symmetry and comprises two terminal planar guanidinium groups, which share an N—C—N unit. Each cation in (I) builds 14 N—H...O hydrogen bonds and is separated from adjacent cations by seven nitrate anions. The AG self-condensation reaction in the presence of copper(II) chloride and chloride anions led to the formation of the organic–inorganic hybrid 1,2-bis(diaminomethylidene)hydrazine-1,2-diium tetrachloridocuprate(II), (C2H10N6)[CuCl4], (II). Its asymmetric unit is composed of half a diprotonated 1,2-bis(diaminomethylidene)hydrazine-1,2-diium dication and half a tetrachloridocuprate(II) dianion, with the CuII atom situated on a twofold rotation axis. The planar guanidinium fragments in (II) have their planes twisted by approximately 77.64 (5)° with respect to each other. The tetrahedral [CuCl4]2− anion is severely distorted and its pronounced `planarity' must originate from its involvement in multiple N—H...Cl hydrogen bonds. It was reported that [CuCl4]2− anions, with a trans-Cl—Cu—Cl angle (Θ) of ∼140°, are yellow–green at room temperature, with the colour shifting to a deeper green as Θ increases and toward orange as Θ decreases. Brown salt (II), with a Θ value of 142.059 (8)°, does not fit the trend, which emphasizes the need to take other structural factors into consideration. In the crystal of salt (II), layers of cations and anions alternate along the b axis, with the minimum Cu...Cu distance being 7.5408 (3) Å inside a layer. The structures of salts (I) and (II) were substantiated via spectroscopic data. The endothermic reaction involved in the thermal decomposition of (I) requires additional oxygen. The title salts may be useful for the screening of new substances with biological activity.

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42

Stevens, E. B. H., and M. Fordham. "Interstitial condensation in building structures : Dynamic model for predicting the amount of condensation." Building Services Engineering Research and Technology 17, no. 1 (February 1996): 47–54. http://dx.doi.org/10.1177/014362449601700108.

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43

Liu, M. C., J. Han, A. J. Brearley, and A. T. Hertwig. "Aluminum-26 chronology of dust coagulation and early solar system evolution." Science Advances 5, no. 9 (September 2019): eaaw3350. http://dx.doi.org/10.1126/sciadv.aaw3350.

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Dust condensation and coagulation in the early solar system are the first steps toward forming the terrestrial planets, but the time scales of these processes remain poorly constrained. Through isotopic analysis of small Ca-Al–rich inclusions (CAIs) (30 to 100 μm in size) found in one of the most pristine chondrites, Allan Hills A77307 (CO3.0), for the short-lived 26Al-26Mg [t1/2 = 0.72 million years (Ma)] system, we have identified two main populations of samples characterized by well-defined 26Al/27Al = 5.40 (±0.13) × 10−5 and 4.89 (±0.10) × 10−5. The result of the first population suggests a 50,000-year time scale between the condensation of micrometer-sized dust and formation of inclusions tens of micrometers in size. The 100,000-year time gap calculated from the above two 26Al/27Al ratios could also represent the duration for the Sun being a class I source.

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44

Elmegreen, Bruce G. "What do we really know about Cloud Formation?" Symposium - International Astronomical Union 169 (1996): 551–60. http://dx.doi.org/10.1017/s0074180900230325.

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Four processes of molecular cloud formation are discussed: formation in swept-up shells, coagulation of smaller clouds, condensation in larger clouds, and compression in a supersonically turbulent medium. Examples and constraints for each process are given.

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45

Dymaczewski, Zbysław, Edward S. Kempa, and Marek M. Sozanski. "Coagulation as a structure-forming separation process in water and wastewater treatment." Water Science and Technology 36, no. 4 (August 1, 1997): 25–32. http://dx.doi.org/10.2166/wst.1997.0078.

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This paper presents the results of research on coagulation sludge properties in three waterworks. The investigation assumed: chemical composition, specific surface of coagulation structures, their sedimentation, gravity thickening and rheological parameters. The solid fraction of the examined structures consisted mostly of mineral substances, especially silica, aluminium and iron oxides. This composition is typical for most coagulation sludges formed in surface water treatment facilities. It has been determined, that the main factor determining structures properties is chemical composition of the solid fraction, mainly alum and iron oxides. Their presence in the sludge causes a high specific surface in coagulation structures, and significantly influences the rheological properties. It has been proved that non-Newtonian properties appear first in structures with the highest contents of alum and iron oxides, with limit concentrations of c. 1.5%. Investigations on sedimentation and gravitational thickening showed a high stability of coagulation structures vs. forces. The water amount in the investigated sludges during their compression was no lower than 94-98%, which means that gravitational forces did not destroy these structures. The factors stabilizing coagulation sludges are; fine dispersion of the solid phase and high affinity to water molecules. This is why in the range of hydrations lower than the compression hydration, the coagulation structures are classified as quasihomogenous systems consisting of two interpenetrating quasicontinuous media, which means; solution of liquid dispersed to colloidal and semicolloidal particles of the solid phase. They act on each other by intermolecular forces, which are the volume forces.

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46

Piskunov, V. N., and A. M. Petrov. "Condensation/coagulation kinetics for mixture of liquid and solid particles: analytical solutions." Journal of Aerosol Science 33, no. 4 (April 2002): 647–57. http://dx.doi.org/10.1016/s0021-8502(01)00206-3.

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47

Chae, Dongho, and Pavel Dubovskiǐ. "Existence and Uniqueness for Spatially Inhomogeneous Coagulation-Condensation Equation with Unbounded Kernels." Journal of Integral Equations and Applications 9, no. 3 (June 1997): 219–36. http://dx.doi.org/10.1216/jiea/1181076013.

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48

Turco, Richard P., and Fangqun Yu. "Particle size distributions in an expanding plume undergoing simultaneous coagulation and condensation." Journal of Geophysical Research: Atmospheres 104, no. D16 (August 1, 1999): 19227–41. http://dx.doi.org/10.1029/1999jd900321.

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49

Zhao, Haibo, Chuguang Zheng, and Minghou Xu. "Multi-Monte Carlo method for coagulation and condensation/evaporation in dispersed systems." Journal of Colloid and Interface Science 286, no. 1 (June 2005): 195–208. http://dx.doi.org/10.1016/j.jcis.2004.12.037.

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50

Shigeta, Masaya, Yusuke Hirayama, and Emanuele Ghedini. "Computational Study of Quenching Effects on Growth Processes and Size Distributions of Silicon Nanoparticles at a Thermal Plasma Tail." Nanomaterials 11, no. 6 (May 21, 2021): 1370. http://dx.doi.org/10.3390/nano11061370.

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In this paper, quenching effects on silicon nanoparticle growth processes and size distributions at a typical range of cooling rates in a thermal plasma tail are investigated computationally. We used a nodal-type model that expresses a size distribution evolving temporally with simultaneous homogeneous nucleation, heterogeneous condensation, interparticle coagulation, and melting point depression. The numerically obtained size distributions exhibit similar size ranges and tendencies to those of experiment results obtained with and without quenching. In a highly supersaturated state, 40–50% of the vapor atoms are converted rapidly to nanoparticles. After most vapor atoms are consumed, the nanoparticles grow by coagulation, which occurs much more slowly than condensation. At higher cooling rates, one obtains greater total number density, smaller size, and smaller standard deviation. Quenching in thermal plasma fabrication is effectual, but it presents limitations for controlling nanoparticle characteristics.

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