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Coagulation kinetics and structure formation

Published on Jan 1, 1987
· DOI :10.1007/978-1-4757-0617-8
Hans Sonntag4
Estimated H-index: 4
,
Klaus Strenge4
Estimated H-index: 4
,
Brian Vincent50
Estimated H-index: 50
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Abstract
Colloidal dispersions play a very important role in nature, industry, and daily life. Sometimes, long-term stability is observed or desired as in ferrotluids (composed of very small magnetic particles with radii of 10 nm), which must be stable even in external fields. On the other hand, only short-term stable dispersions may be necessary during actual processing operations, for example, dispersions of magnetite particles during tape manufacture. The stability of dispersions and many of their physical properties are related to the interaction between the particles in the dispersion medium, which may contain surfactants or macromolecular species. If the net interparticle interaction forces are attractive, then aggregation may occur. Two general types of aggregation behavior may be distinguished: coagulation and flocculation. These two terms are frequently used synonymously but IUPAC has recommended the following definitions: Coagulation implies formation of compact aggregates, leading to the macroscopic separation. Flocculation implies the formation of a loose or open network, floc, which may or may not separate macroscopically. Flocculation brought about by the simultaneous coadsorption of polymer molecules on two (or more) particles is referred to as bridging flocculation. If coagulation results in the merging of two particles into one, as may occur with liquid droplets in emulsions, this process is referred to as coalescence.
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  • Citations (169)
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Cited By169
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Joseph T. Nwabanne4
Estimated H-index: 4
(Nnamdi Azikiwe University),
Ozioma Onyinye Oguegbu (Nnamdi Azikiwe University), Chinedu M. Agu2
Estimated H-index: 2
(Nnamdi Azikiwe University)
Published on Feb 16, 2018in Physical Review E2.35
Agata Fronczak11
Estimated H-index: 11
,
Anna Chmiel9
Estimated H-index: 9
,
Piotr Fronczak12
Estimated H-index: 12
The paper outlines an exact combinatorial approach to finite coagulating systems. In this approach, cluster sizes and time are discrete, and the binary aggregation alone governs the time evolution of the systems. By considering the growth histories of all possible clusters, the exact expression is derived for the probability of a coagulating system with an arbitrary kernel being found in a given cluster configuration when monodisperse initial conditions are applied. Then, this probability is use...
Published on Jan 1, 2018
Alexander Herega (Odesa National Academy of Food Technologies)
The fourth chapter of the monograph describes a simulation computer model of coagulation of a solid phase of a circulating two-phase gas stream under conditions of centrifugal force. The model makes it possible to study the structure and properties of forming clusters, the effect of the dispersed phase and the effect of the structure in which the motion takes place, the role of particle interaction, and the influence of chaotic flow parameters. In the monograph types of model, clusters are descr...
Published on Jun 1, 2017in Journal of Materials Science3.44
D. V. Alexandrov (UrFU: Ural Federal University)
There are a number of experimental and theoretical papers testifying that the large-time behavior of the particle-size distribution function heavily depends on the initial conditions at the final stages of phase transformation processes. However, still now there is no theoretically derived distribution confirming these conclusions. The present paper is concerned with a new theoretical approach verifying the fact that the large-time distribution can actually be dependent on the details of the ini...
Published on Feb 1, 2017in Journal of Dispersion Science and Technology1.48
Kareem Rahn-Chique3
Estimated H-index: 3
(IVIC: Venezuelan Institute for Scientific Research),
German Urbina-Villalba12
Estimated H-index: 12
(IVIC: Venezuelan Institute for Scientific Research)
ABSTRACTThis study reports the behavior of ionic dodecane-in-water nanoemulsions in distinct salt concentrations. Systems of smaller particle size (74–285 nm) were synthesized by a sudden dilution of an equilibrated mixture. Larger size systems (384–670 nm) were obtained from a set of formerly smaller nanoemulsions that evolved unperturbed for 2 weeks. Characteristic destabilization times for flocculation, coalescence, and Ostwald ripening were evaluated. In general, it was observed that stabili...
Published on Dec 1, 2016in Archives of Acoustics0.90
Vladimir N. Khmelev8
Estimated H-index: 8
(Altai State Technical University),
Andrey V. Shalunov7
Estimated H-index: 7
(Altai State Technical University)
+ 4 AuthorsKsenija V. Shalunova1
Estimated H-index: 1
(Altai State Technical University)
The article presents the results of research aimed at increase of the efficiency of gas cleaning equipment based on the Venturi tube using high-intensity ultrasound. The model based on known laws of hydrodynamics of multiphase mediums of dust-extraction in Venturi scrubbers was proposed. Modification of this model taking into account ultrasonic field allows evaluating optimum modes (sound pressure level) and conditions (direction of ultrasonic field, square and number of ultrasonic sources) of u...
Published on Jun 1, 2016in Journal of Environmental Sciences-china3.56
R. Wardzyńska4
Estimated H-index: 4
(University of Warmia and Mazury in Olsztyn),
B. Załęska-Chróst3
Estimated H-index: 3
(University of Warmia and Mazury in Olsztyn)
Abstract The results of studies carried out using a computer programme simulating the coagulation of suspensions containing spherical sol particles and spherical coagulant particles are reported. The influence of the degree of dispersion of the system on the coagulation reaction kinetics was investigated. The obtained results of kinetic studies were tested in the light of classical Muller–Smoluchowski equations. The influence of the physical properties of the coagulant, such as size, density and...
Published on Jan 1, 2016in Colloid Journal0.97
A. I. Dolinnyi2
Estimated H-index: 2
(RAS: Russian Academy of Sciences)
By using the generalized Mie theory, the extinction cross sections for dimers of 46-nm gold particles immersed in water have been calculated. It has been found that, in the region of high-energy plasmon resonance band, the maximum value of normalized extinction cross section Qext1 gradually decreases as particles approach each other. The greatest changes in Qext1 are observed when interparticle distance h decreases from 10 to 3 nm. At shorter distances, Qext1 weakly depends on h. At the same tim...
Published on Jan 1, 2005
David Lee. Craft1
Estimated H-index: 1
(MIT: Massachusetts Institute of Technology),
Lawrence M. Wein44
Estimated H-index: 44
(Stanford University),
Dennis J. Selkoe161
Estimated H-index: 161
(Brigham and Women's Hospital)
Motivated by recent therapeutic initiatives for Alzheimer’s disease, we developed a mathematical model of the accumulation of amyloid β-protein (Aβ) in the brain. The model incorporates the production and clearance of Aβ monomers, and the elongation and fragmentation of polymers by monomer aggregation and break-off, respectively. Our analysis suggests that Aβ dynamics are dictated by a single unitless measure referred to as the polymerization ratio, which is the product of the production and elo...