Biomedical subjects

VA Bogoyavlenskiy

Publications and source records attributed to VA Bogoyavlenskiy.

3 recordsLinked to original sources

PubMed2000

Diffusion-limited aggregation: A relationship between surface thermodynamics and crystal morphology

We have combined the original diffusion-limited aggregation model introduced by Witten and Sander with the surface thermodynamics of the growing solid aggregate. The theory is based on the consideration of the surface chemical potential as a thermodynamic function of the temperature and nearest-neighbor configuration. The Monte Carlo simulations on a two-dimensional square lattice produce the broad range of shapes such as fractal dendritic structures, densely branching patterns, and compact aggregates. The morphology diagram illustrating the relationship between the model parameters and cluster geometry is presented and discussed.

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PubMed2000

Diffusion-limited aggregation: a revised mean-field approach

We propose a revision of the classic mean-field approach of diffusion-limited aggregation (DLA) model originally introduced by Witten and Sander [Phys. Rev. Lett. 47, 1400 (1981)]. The derived nonlinear mean-field equations providing lattice anisotropy are used to model diffusional growth on square lattice in linear and circular source geometries. The overall cluster shapes obtained from the mean-field calculations are found to satisfy the known scaling behavior experimentally observed for DLA simulations.

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PubMed2000

Single-bubble sonoluminescence: shape stability analysis of collapse dynamics in a semianalytical approach

This paper theoretically analyzes the hydrodynamic shape stability problem for sonoluminescing bubbles. We present a semianalytical approach to describe the evolution of shape perturbations in the strongly nonlinear regime of violent collapse. The proposed approximation estimating the damping rate produced by liquid viscosity is used to elucidate the influence of the collapse phase on subsequent evolution of the Rayleigh-Taylor instability. We demonstrate that time derivatives of shape perturbations grow significantly as the bubble radius vanishes, forming the dominant contribution to destabilization during the ensuing bounce phase. By this effect the Rayleigh-Taylor instability can be enhanced drastically, yielding a viable explanation of the upper threshold of driving pressure experimentally observed by Barber et al. [Phys. Rev. Lett. 72, 1380 (1994)].

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