Aerogelation Process Simulation by a Cluster-Cluster Aggregation Algorithm |
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Authors: | Hasmy Anwar |
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Institution: | (1) Laboratorio de Física Estadística de Sistemas Desordenados, Centro de Física, IVIC, Apartado 21827, Caracas, 1020A, Venezuela |
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Abstract: | A ballistically-limited cluster-cluster aggregation (BLCA) model was developed to simulate aerogelation processes. In the model, the clusters move along linear paths, in random directions, in a finite box. When two aggregates contact each other, they are combined irreversibly to form a larger aggregate. As expected, the simulations show that the aggregation time is much shorter than that obtained with diffusion-limited cluster-cluster aggregation (DLCA) models. The minimum concentration, cg, required for gel formation scales as LD–3, where L is the length of the sides of the box and D is the fractal dimension of the aggregates (D 1.95). For a concentration c larger than cg, the mean free path of the aggregating clusters, , scales as c–1.1. The pair correlation function g(r) and its Fourier transform S(q) were determined for the single large aggregates formed at the end of the simulations. These functions indicate that there is a characteristic length which scales as c1/(D–3). As observed previously for the DLCA model, there is a discrepancy between the fractal dimensions obtained from g(r) and S(q). |
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Keywords: | aggregation gelation aerosol fractals computer simulation |
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