arXiv subjects

Andrei S. Burmistrov

Publications and source records attributed to Andrei S. Burmistrov.

4 recordsLinked to original sources

arXiv2026

Hierarchical crack patterns: Identification of crack generations

Identifying crack generations from microscopic images of hierarchical crack patterns is challenging due to the lack of temporal information and sensitivity to image boundaries. Existing algorithms often fragment individual cracks or lose stability when the observed fragment is shifted. We propose a method that reduces the classification problem to topological sorting of a directed acyclic graph (descendant$\to$parent), built from T-junctions and nearly collinear edges. Sequential removal of leaf vertices assigns generation numbers starting from the youngest. On 100 computer-generated networks, our method correctly classifies $\approx 70$\% of cracks at a window size of only three mean edge lengths, whereas a conventional approach that starts from primary cracks drops nearly to zero. The classification is highly stable against reasonable shifts of image boundaries but remains limited to strictly hierarchical networks.

cond-mat.dis-nn↗

arXiv2026

Algorithms for generating planar networks simulating hierarchical patterns of cracks formed during film drying

Hierarchical crack patterns that arise during the drying of thin films of colloidal dispersions or polymer solutions on a solid substrate are of interest both from a fundamental standpoint and in the context of the creation of transparent electrodes for optoelectronics. This paper analyzes the morphology of such patterns based on image processing of real-world samples. Graph theory is used to extract chains of edges and analyze the network topology. A method based on the hierarchy of connections is applied to classify cracks by generation. The limitations of existing classification approaches related to the discreteness of the time scale and the use of only a part of the entire pattern are discussed. Three approaches are used to generate artificial hierarchical networks: random uniform partitioning, recursive Voronoi partitioning, and a crack growth simulation model, each modified to reproduce the hierarchical structure. A comparison was made of the geometric characteristics (distribution of crack angles, edge lengths, cell areas, and circularity coefficient) and topological properties (distribution of the number of cell sides) of real and simulated networks. It was shown that the simulation model best reproduces the key features of real cracks, including the characteristic right angles of their connections.

cond-mat.dis-nn↗

arXiv2017

Pattern formation in a two-dimensional two-species diffusion model with anisotropic nonlinear diffusivities: a lattice approach

Diffusion in a two-species 2D system has been simulated using a lattice approach. Rodlike particles were considered as linear $k$-mers of two mutually perpendicular orientations ($k_x$- and $k_y$-mers) on a square lattice. These $k_x$- and $k_y$-mers were treated as species of two kinds. A random sequential adsorption model was used to produce an initial homogeneous distribution of $k$-mers. The concentration of $k$-mers, $p$, was varied in the range from 0.1 to the jamming concentration, $p_j$. By means of the Monte Carlo technique, translational diffusion of the $k$-mers was simulated as a random walk, while rotational diffusion was ignored. We demonstrated that the diffusion coefficients are strongly anisotropic and nonlinearly concentration-dependent. For sufficiently large concentrations (packing densities) and $k \geq 6$, the system tends toward a well-organized steady state. Boundary conditions (BC) predetermine the final state of the system. When periodic BCs are applied along both directions of the square lattice, the system tends to a steady state in the form of diagonal stripes. The formation of stripe domains takes longer time the larger the lattice size, and is observed only for concentrations above a particular critical value. When insulating (zero flux) BCs are applied along both directions of the square lattice, each kind of $k$-mer tries to completely occupy a half of the lattice divided by a diagonal, e.g., $k_x$-mers locate in the upper left corner, while the $k_y$-mers are situated in the lower right corner ("yin-yang" pattern). From time to time, regions built of $k_x$- and $k_y$-mers exchange their locations through irregular patterns. When mixed BCs are used (periodic BCs are applied along one direction whereas insulating BCs are applied along the other one), the system still tends to form the stripes, but they are unstable and change their spatial orientation.

cond-mat.stat-mech↗

arXiv2015

Percolation and jamming of linear $k$-mers on square lattice with defects: effect of anisotropy

We study the percolation and jamming of rods ($k$-mers) on a square lattice that contains defects. The point defects are placed randomly and uniformly on the substrate before deposition of the rods. The general case of unequal probabilities for orientation of depositing of rods along different directions of the lattice is analyzed. Two different models of deposition are used. In the relaxation random sequential adsorption model (RRSA), the deposition of rods is distributed over different sites on the substrate. In the single cluster relaxation model (RSC), the single cluster grows by the random accumulation of rods on the boundary of the cluster. For both models, a suppression of growth of the infinite cluster at some critical concentration of defects $d_c$ is observed. In the zero defect lattices, the jamming concentration $p_j$ (RRSA) and the density of single clusters $p_s$ (RSC) decrease with increasing length rods and with a decrease in the order parameter. For the RRSA model, the value of $d_c$ decreases for short rods as the value of $s$ increases. For longer rods, the value of $d_c$ is almost independent of $s$. Moreover, for short rods, the percolation threshold is almost insensitive to the defect concentration for all values of $s$. For the RSC model, the growth of clusters with ellipse-like shapes is observed for non-zero values of $s$. The density of the clusters $p_s$ at the critical concentration of defects $d_c$ depends in a complex manner on the values of $s$ and $k$. For disordered systems, the value of $p_s$ tends towards zero in the limits of the very long rods and very small critical concentrations $d_c \to 0$. In this case, the introduction of defects results in a suppression of rods stacking and in the formation of `empty' or loose clusters with very low density. On the other hand, denser clusters are formed for ordered systems.

cond-mat.stat-mech↗