Aggregation, computer models

Fumed Silica Structure and Particle Aggregation Computational Modelling and Verification by Vibrational Spectroscopy... 

Mumtaz, H.S., Hounslow, M.I., Seaton, N.A. and Paterson, W.R., 1997. Orthokinetic aggregation during precipitation A computational model for calcium oxalate monohydrate. Transactions of the Institution of Chemical Engineers, 75, 152-159. 

More than 20 years ago, Matsushita et al. observed macroscopic patterns of electrodeposit at a liquid/air interface [46,47]. Since the morphology of the deposit was quite similar to those generated by a computer model known as diffusion-limited aggregation (D LA) [48], this finding has attracted a lot of attention from the point of view of morphogenesis in Laplacian fields. Normally, thin cells with quasi 2D geometries are used in experiments, instead of the use of liquid/air or liquid/liquid interfaces, in order to reduce the effect of convection. 

For example, studies of the morphology of a number of flame-generated aggregates (different carbonaceous soots, A1203 aerosols, etc.) [203] by both TEM and ALS procedures resulted in D2 = 1.7 0.15, while analysis of silhouettes of computer models of seven proteins [211] gave a value of D2 = 1.120 0.025, etc. 

Elimelech, M., Gregory, J., Jia, X., and Williams, R., Particle Deposition and Aggregation Measurement, Modelling and Simulation, Butterworth-Heinemann, Oxford, England, 1995. (Graduate and research levels. A state-of-the-art treatment of deposition of colloidal particles and their dependence on colloidal forces. Includes theoretical, computational, and experimental approaches.)... 

The diastereoselectivity of protonation of enolate anions has been studied by H/D exchange.156 /i-Substituted ethyl butanoates were chosen as substrates, with conditions that rigorously excluded ion-pairing and aggregation effects. Stereoelectronic effects were found typically to produce higher stereoselection than purely steric effects, hi the specific case of H/D exchange in 3-ethoxybutanoate in ethanol-4 protonation of the enolate of 3-fluorobutanoate was chosen as a computational model.157 Similar... 

See Chapter V of R. Jullien and R. Botet, Aggregation and Fractal Aggregates, World Scientific, Singapore, 1987, for a description of cluster-cluster flocculation processes in the context of computer models. 

Use computational methods that have been developed to rapidly and automatically identify potential frequent hitters (Roche et al., 2002 Seidler et al., 2003 Feng et al., 2005). Predictive models show some potential for predicting aggregation-based promiscuity in large libraries. A caveat of computational models is that they remain too crude to capture the concentration dependence of aggregate formation. 

Fig. VII-13. Structure of particle aggregate obtained by computer modeling of two-dimensional aggregation...

Computer modeling is the simplest and most productive approach for studying kinetic processes. In recent years the varied variants for solving these problems have been developed [127, 128]. Thus, in the frame of the model of diffusive-restricted aggregation the computer modeling of the kinetics of... 

It is well known that polymers may serve as bridges between colloidal particles to form floes nonetheless, very little quantitative information is available about their structure and formation, despite the fact that they play key roles in environmental systems [1], Particles may not only be bridged by polymers, but may also facilitate the formation of larger aggregates due to the adsorption of several polymer segments on the same particles. This process can be seen as an example of the CCA model, where polymer conformation, reactivity and total length play important roles. Computer models once again constitute a valuable tool that allows for predictions of flocculation processes. 

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