Predictive Model for Diffusion-Limited Aggregation Kinetics of Nanocolloids under High Concentration

In this work, the kinetics of aluminum-induced crystallization (AIC) of non-stoichiometric silicon oxide a-SiO0.25 was investigated for annealing temperatures of 370, 385 and 400 °C, as a result of which thin films of polycrystalline silicon were obtained. It is shown that for low annealing temperatures, the surface morphology of the crystalline material is represented by dendric structures corresponding to the growth model with diffusion-limited aggregation. In addition, with an increase in the annealing temperature, the nucleation density increases from 3 to 53 mm–2. From the Arrhenius plot, the activation energy of the AIC process of a-SiO0.25 was obtained for the first time, which was 3.7±0.4 eV.

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Influence of Electrolytes and Humic Acid on Aggregation Behavior of C60 Nanoparticles in Aquatic System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.448-453.48 ◽

2013 ◽

Vol 448-453 ◽

pp. 48-51

Author(s):

Hua Fang ◽

Bing Bing Shen ◽

Yu Xin Sun ◽

Yuan Wang ◽

Ji Lai Lu

Keyword(s):

Humic Acid ◽

Colloidal Stability ◽

Dlvo Theory ◽

Aquatic Environments ◽

Aggregation Kinetics ◽

Time Resolved ◽

Diffusion Limited ◽

Wide Range ◽

Kinetics Of ◽

And Diffusion

The aggregation kinetics of C60 nanoparticles have been investigated over a wide range of monovalent and divalent electrolyte concentrations by employing time-resolved dynamic light scattering (DLS). The results showed that the presence of electrolyte made a dramatic decrease in the surface zeta potential and increase in the particle size. The aggregation kinetics of C60 nanoparticles exhibited reaction-limited and diffusion-limited regimes, which was found to be consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. The critical coagulation concentration (CCC) values of C60 nanoparticles were estimated as 321mM Na+, 295mM K+, 9.6mM Ca2+and 6.7mM Mg2+, which were far higher than the electrolyte concentrations in natural water. The enhanced C60 stability in the presence of humic acid was attributable to steric repulsion. Therefore C60 nanoparticles can be relatively stable in typical aquatic environments.

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Fractal Concepts And Aggregation Of Iron Oxides

MRS Proceedings ◽

10.1557/proc-180-299 ◽

1990 ◽

Vol 180 ◽

Author(s):

R. Amal ◽

J.A. Raper ◽

T.D. Waite

Keyword(s):

Light Scattering ◽

Dynamic Light Scattering ◽

Iron Oxides ◽

Aggregate Size ◽

Fractal Dimensions ◽

Aggregation Kinetics ◽

Diffusion Limited ◽

Scattering Measurements ◽

The Relationship ◽

Kinetics Of

ABSTRACTThe modelling of the aggregation kinetics of iron oxides has been succesful in predicting the increase in aggregate size as determined by dynamic light scattering measurements. The aggregates were found to exhibit fractal behaviour with fractal dimensions obtained from the scattering exponent in static light scattering studies dependent on the aggregation mechanism and ranging from 2.3 for rapid (diffusion limited) to 2.8 for slow (reaction limited) aggregation. Polydispersity and restructuring of aggregates were found not to affect the relationship between scattering exponent and aggregate fractal dimension. Excellent correspondence over a range of temperatures and ionic strengths has been obtained between results of sizing experiments using dynamic light scattering and sizes predicted using a modified Smoluchowski model incorporating fractal dimensions.

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Investigation into mechanisms and kinetics of asphaltene aggregation in toluene/n-hexane mixtures

Petroleum Science ◽

10.1007/s12182-019-00383-3 ◽

2019 ◽

Vol 17 (2) ◽

pp. 457-466

Author(s):

Bahram Soltani Soulgani ◽

Fatemeh Reisi ◽

Fatemeh Norouzi

Keyword(s):

Image Processing ◽

Fractal Theory ◽

Particle Growth ◽

Force Balance ◽

Asphaltene Precipitation ◽

Diffusion Limited Aggregation ◽

Model Calculations ◽

Diffusion Limited ◽

Kinetics Of ◽

And Diffusion

Abstract Determining the rate of asphaltene particle growth is one of the main problems in modeling of asphaltene precipitation and deposition. In this paper, the kinetics of asphaltene aggregation under different precipitant concentrations have been studied. The image processing method was performed on the digital photographs that were taken by a microscope as a function of time to determine the asphaltene aggregation growth mechanisms. The results of image processing by MATLAB software revealed that the growth of asphaltene aggregates is strongly a function of time. Different regions could be recognized during asphaltene particle growth including reaction- and diffusion-limited aggregation followed by reaching the maximum asphaltene aggregate size and start of asphaltene settling and the final equilibrium. Modeling has been carried out to predict the growth of asphaltene particle size based on the fractal theory. General equations have been developed for kinetics of asphaltene aggregation for reaction-limited aggregation and diffusion-limited aggregation. The maximum size of asphaltene aggregates and settling time were modeled by using force balance, acting on asphaltene particles. Results of modeling show a good agreement between laboratory measurements and model calculations.

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Beyond diffusion-limited aggregation kinetics in microparticle suspensions

Physical Review E ◽

10.1103/physreve.80.051402 ◽

2009 ◽

Vol 80 (5) ◽

Cited By ~ 11

Author(s):

Randall M. Erb ◽

Melissa D. Krebs ◽

Eben Alsberg ◽

Bappaditya Samanta ◽

Vincent M. Rotello ◽

...

Keyword(s):

Aggregation Kinetics ◽

Diffusion Limited Aggregation ◽

Diffusion Limited

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Cellular Automata Modeling of Silica Aerogel Condensation Kinetics

Gels ◽

10.3390/gels7020050 ◽

2021 ◽

Vol 7 (2) ◽

pp. 50

Author(s):

Nina H. Borzęcka ◽

Bartosz Nowak ◽

Rafał Pakuła ◽

Robert Przewodzki ◽

Jakub M. Gac

Keyword(s):

Condensation Reaction ◽

Gelation Time ◽

Aggregate Size ◽

Collision Probability ◽

Model Parameters ◽

Gel Properties ◽

Diffusion Limited Aggregation ◽

Diffusion Limited ◽

Kinetics Of ◽

Simulation Time

The formation of silica aerogels and the kinetics of condensation were investigated numerically. The influence of the reaction-limited to the diffusion-limited aggregation (RLA to DLA) transition on the reaction kinetics curves and the evolution of the aggregate size distribution during condensation were examined. The 2D cellular automaton was developed and applied to reflect the process of secondary particle aggregation. Several tendencies were observed due to the adjustment of the model parameters: the probability of condensation reaction and the particles’ concentration. The final wet-gel structures’ visualizations proves that the structure becomes more dense and compact due to entering the RLA regime. The simulation time (associated with the gelation time) decreased along with the increase in both model parameters. The lower the collision probability, the slower reaction becomes, and particles are more likely to penetrate the structure deeper until they finally join the aggregate. The developed model reflects the condensation process’s nature and its mechanisms properly and indicates a significant potential for further aerogel synthesis investigations and for the prediction of wet-gel properties according to condensation parameters.

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Functional Fractionation of Platelets: Aggregation Kinetics and Glycoprotein Labeling of Differing Platelet Populations

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657259 ◽

1982 ◽

Vol 48 (02) ◽

pp. 211-216 ◽

Cited By ~ 12

Author(s):

V M Haver ◽

A R L Gear

Keyword(s):

Galactose Oxidase ◽

Aggregation Kinetics ◽

Maximal Rate ◽

Membrane Glycoproteins ◽

Whole Cells ◽

Reversible Aggregation ◽

Significant Difference ◽

Small Doses ◽

Major Loss ◽

Kinetics Of

SummaryPlatelet heterogeneity has been studied with a technique called functional fractionation which employs gentle centrifugation to yield subpopulations (“reactive” and “less-reactive” platelets) after exposure to small doses of aggregating agent. Aggregation kinetics of the different platelet populations were investigated by quenched-flow aggregometry. The large, “reactive” platelets were more sensitive to ADP (Ka = 1.74 μM) than the smaller “less-reactive” platelets (Ka = 4.08 μM). However, their maximal rate of aggregation (Vmax, % of platelets aggregating per sec) of 23.3 was significantly lower than the “less-reactive” platelets (Vmax = 34.7). The “reactive” platelets had a 2.2 fold higher level of cyclic AMP.Platelet glycoproteins were labeled using the neuraminidase-galactose oxidase – [H3]-NaBH4 technique. When platelets were labeled after reversible aggregation, the “reactive” platelets showed a two-fold decrease in labeling efficiency (versus control platelets). However, examination of whole cells or membrane preparations from reversibly aggregated platelets revealed no significant difference in Coomassie or PAS (Schiff) staining.These results suggest that the large, “reactive” platelets are more sensitive to ADP but are not hyperaggregable in a kinetic sense. Reversible aggregation may cause a re-orientation of membrane glycoproteins that is apparently not characterized by a major loss of glycoprotein material.

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Vancomycin Adsorption During in vitro Model of Hemoperfusion with HA380 Cartridge

Nephron ◽

10.1159/000513122 ◽

2021 ◽

pp. 1-7

Author(s):

Ilaria Godi ◽

Anna Lorenzin ◽

Silvia De Rosa ◽

Gianlorenzo Golino ◽

Maira Knust ◽

...

Keyword(s):

Complete Removal ◽

Potential Interaction ◽

Blood Purification ◽

Therapeutic Monitoring ◽

High Concentration ◽

Langmuir Isotherm Model ◽

Vitro Model ◽

Kinetics Of ◽

Balanced Solution

Introduction: A critical point for using blood purification during sepsis may be the potential interaction with antimicrobial therapy, the mainstay of sepsis treatment. The aim of our study was to investigate the vancomycin removal during hemoperfusion (HP) using HA380 cartridge. Methods: This is an experimental study, in which 500 mL of solution was circulated in a closed-circuit (blood flow of 250 mL/min) simulating HP ran using HA380. Vancomycin was added to reach a through concentration or a very high concentration to evaluate the removal ratio (RR) during 120 min of HP. Comparison between blood-crystalloid solution and balanced solution was performed by using Kruskal-Wallis test. The kinetics of vancomycin removal and the adsorption isotherm were evaluated. Results: We found a complete removal of vancomycin at baseline through concentration of 23.0 ± 7.4 mg/L. Using extremely high concentration (baseline 777.0 ± 62.2 mg/L), RR was 90.1 ± 0.6% at 5 min and 99.2 ± 0.6% at 120 min. No difference in terms of RR was found between blood-crystalloid mixture and balanced solution. The kinetics of the vancomycin reduction followed an exponential decay. Repeated boluses (total amount of 2,000 mg) resulted in cumulative adsorption of 1,919.4 mg with RR of 96.6 ± 1.4%, regardless of the amount injected (100 vs. 500 mg). Vancomycin adsorption onto HA380 followed the Langmuir isotherm model. Conclusions: A considerable amount of vancomycin was rapidly removed during in vitro HP with HA380. Clinical studies are needed to determine whether this may lead to underdosing. Drug therapeutic monitoring is highly recommended when using HA380 for blood purification in patients receiving vancomycin.

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