arXiv subjects

Taras Patsahan

Publications and source records attributed to Taras Patsahan.

6 recordsLinked to original sources

arXiv2026

Equilibrium Adsorption of Hard Disks on Patterned Adhesive Surfaces: A Monte Carlo Simulation Study

Equilibrium adsorption of disk-like particles on patterned adhesive surfaces is studied using Monte Carlo simulations. The surface is represented as a two-dimensional plane with circular adhesive domains arranged either regularly or randomly, while the particles are modelled as hard disks. The interaction energy between a particle and the surface is defined by the contact area between the particle and the adhesive domains. It is shown that the adsorption behaviour is controlled not only by the total area of the adhesive regions, but also by the geometry of the surface pattern. In particular, the domain size is found to have a significant effect on the adsorption efficiency. The most pronounced effect is observed when the particle and domain sizes are equal, which leads to enhanced adsorption at intermediate values of the chemical potential. At high values of the chemical potential, however, when the particle surface coverage increases, steric effects become important, which weakens the influence of the surface pattern geometry. The obtained results demonstrate that the adsorption efficiency and surface organization of particles can be tuned by choosing the size, coverage, and spatial arrangement of adhesive domains. This study may be useful in the design of functional surfaces, selective adsorption platforms, biosensors, and affinity-based cell sorting systems.

cond-mat.soft↗

arXiv2025

Chelation of the mercury ions by polyethyleneimine: Atomistic molecular dynamics study

Contamination of water by heavy metal ions represents a significant environmental concern. Among various remediation methods, chelation has proven to be an effective technique in water treatment processes. This study investigates the chelating properties of linear polyethyleneimine (PEI) and its complexation with divalent mercury ions (Hg2+) in aqueous solution. Atomistic molecular dynamics (MD) simulations were carried out using the OPLS/AA force field to examine the microscopic structure of PEI-Hg2+ complexes. PEI chains of varying lengths were considered, and it was found that a single linear PEI molecule containing ten amino groups is capable of coordinating up to four Hg2+ ions. The stability of the resulting complexes was further supported by density functional theory (DFT) calculations.

cond-mat.soft↗

arXiv2023

Phase Behavior of the Patchy Colloids Confined in the Patchy Porous Media

A simple model for functionalized disordered porous media is proposed and the effects of confinement on self-association, percolation and phase behavior of a fluid of patchy particles are studied. The media is formed by a randomly distributed hard-sphere obstacles fixed in space and decorated by a certain number of off-center square-well sites. The properties of the fluid of patchy particles, represented by the fluid of hard spheres each bearing a set of the off-center square-well sites, are studied using an appropriate combination of the scaled particle theory for the porous media, Wertheim's thermodynamic perturbation theory, and the Flory-Stockmayer theory. To assess the accuracy of the theory a set of computer simulations have been performed. In general, predictions of the theory appear to be in a good agreement with computer simulation results. Confinement and competition between the formation of bonds connecting the fluid particles, and connecting fluid particles and obstacles of the matrix, give rise to a re-entrant phase behavior with three critical points and two separate regions of the liquid-gas phase coexistence.

cond-mat.soft↗

arXiv2021

Compartmental and cellular automaton $SEIRS$ epidemiology models for the COVID-19 pandemic with the effects of temporal immunity and vaccination

We consider the $SEIRS$ epidemiology model with such features of the COVID-19 outbreak as: abundance of unidentified infected individuals, limited time of immunity and a possibility of vaccination. Within a compartmental realization of this model, we found the disease-free and the endemic stationary states. They exist in their respective restricted regions of the le via linear stability analysis. The expression for the basic reproductive number is obtained as well. The positions and heights of a first peak for the fractions of infected individuals are obtained numerically and are fitted to simple algebraic forms, that depend on model rates. Computer simulations of a lattice-based realization for this model was performed by means of the cellular automaton algorithm. These allowed to study the effect of the quarantine measures explicitly, via changing the neighbourhood size. The attempt is made to match both quarantine and vaccination measures aimed on balanced solution for effective suppression of the pandemic.

q-bio.PE↗

arXiv2021

Modeling of polymer-enzyme conjugates formation: Thermodynamic perturbation theory and computer simulations

A simple model for the formation of the polymer-enzyme conjugates has been proposed and described using corresponding extension of the Wertheim's first-order thermodynamic perturbation theory (TPT1) for the system of associating chain molecules. A set of computer simulation data for different number of functional groups along polymer chains has been obtained and used to access the accuracy of the theoretical results. Predictions of the present theoretical approach are more accurate than that of the conventional TPT1 and are in a very good agreement with the computer simulation data. In particular the theory is able to account for the difference in position of the polymer functional groups along its backbone.

cond-mat.soft↗

arXiv2018

Vapour-liquid critical parameters of a $2$:$1$ primitive model of ionic fluids confined in disordered porous media

We study the vapour-liquid critical parameters of an ionic fluid confined in a disordered porous medium by using the theory which combines the collective variables approach with an extension of the scaled particle theory. The ionic fluid is described as a two-component charge- and size-asymmetric primitive model, and a porous medium is modelled as a disordered matrix formed by hard-spheres obstacles. In the particular case of the fixed valencies $2$:$1$, the coexistence curves and the corresponding critical parameters are calculated for different matrix porosities as well as for different diameters of matrix and fluid particles. The obtained results show that the general trends of the reduced critical temperature and the reduced critical density with the microscopic characteristics are similar to the trends obtained in the monovalent case. At the same time, it is noticed that an ion charge asymmetry significantly weakens the effect of the matrix presence.

cond-mat.stat-mech↗