Aim. We consider the viscoelastic characteristics of melts of polymer composites with filler in the form of carbon nanotubes.

Methodology. The experimental data of dynamic measurements are approximated by the equations of a structural rheological model at separate intervals of the cyclic frequency of shear oscillations.

Results. The possibility of applying the equations of the structural model to describe rheological curves under conditions of linear viscoelasticity is shown. The relationship of the coefficients of rheological equations with the state of the composite material structure is established.

Research implications. Equations are proposed that are capable of approximating experimental data at separate frequency intervals of shear oscillations corresponding to a certain structural state of the polymer melt and polymer composite.

Aim. The possibility of using a nanopore to monitor the functioning of asparaginase has been studied.

Methodology. In this work, a SiN-based nanopore was constructed in which the L-asparaginase molecule was embedded. The catalytic activity of the L-asparaginase molecule, embedded in the nanopore, has been monitored by observing the change in the ion current in the cell with this nanopore. This approach is useful for studying the catalytic activity based on single enzyme molecules embedded in a nanopore.

Results. A nanopore detector for studying the catalytic activity of L-asparaginase has been developed. It has been found that this detector made it possible to monitor the activity of this enzyme.

Research implications. It has been shown that a nanopore detector, with a nanopore size of the order of 6 nm, can be used to study the activity of asparaginase. It is possible to carry out realtime monitoring of changes in the form of L-asparaginase, which consisted in monitoring changes in the ion current passing through a nanopore, in which asparaginase was immobilized. The results obtained can be of use in the analysis of the functioning of enzymes at the level of single molecules. 

Aim. To identify the connection between visual and sound perception.

Methodology. Using Object-Oriented Programming (OOP) of the Python language, we are looking for a way to convert a visual (pixel) display into an audio display. A number of modern and functional libraries are used. Modern methods of “packing” all software components into a single file are used for convenient program deployment on an electronic computing device (computer) with any modern operating system (OS).  

Results. A software product based on a modern OOP programming language and functional libraries has been created that allows you to present the pixel structure of a visual image into an audio display.  

Research implications. The significance lies in the disclosure of a modern way of “packing” all software components into a single file for convenient program deployment on an electronic computing device (computer) with any modern operating system (OS). 

Aim. The purpose of this work was to assess the applicability of first approximation models for describing the flow around surfaces of high curvature (sharp edges).

Methodology.The work used methods of molecular kinetic theory of gases. To numerically solve integral-differential equations, a model kinetic equation of polyatomic gases was used.

Results. The maximum degree of gas disequilibrium medium was calculated in the problem on profile of flat shock wave and in the problem of flow around a thin plate for a diatomic gas in the range of Mach numbers from 2 to 8. An almost twofold increase in the degree of disequilibrium in the region of the plate nose was obtained compared with nonequilibrium on the profile of a plane shock wave.

Research implications. The results obtained confirm the well-known position about the physical inadequacy of first-approximation models, in particular the Navier – Stokes – Fourier (NSF) model, when describing flows around sharp edges. Results can be used to develop flow models aimed at solving this problem. 

The aim of this work was to build a physical and mathematical model of the flows of mixtures of polyatomic gases in the form of a model kinetic equation.  

Methodology. The paper uses methods of the molecular kinetic theory of gases, focused on finding the translational and rotational energies of the components of a gas mixture. To implement the developed model, methods of numerical solution of integral differential equations were used.

Results. The model was tested on the example of a shock wave problem for a mixture of nitrogen and oxygen. A satisfactory agreement with the results of other authors obtained by direct statistical modeling methods is shown.

Research implications. The developed model makes it possible to describe highly nonequilibrium processes in gas mixtures. Such processes include, in particular, the interaction of gas with active surfaces.

Aim. Building a nonlinear turbulence model of a supersonic viscous gas flow around a flat plate.

Methodology. Numerical modeling was applied within the framework of the Navier-Stokes equations without using turbulence models; the calculation results then used to build an analytical solution.

Results. Based on the data from direct numerical modeling of the Navier-Stokes equations, the mechanism of gas emission (burst) from the surface of a thermally insulated plate streamlined by a supersonic gas flow with M = 2 is explained. It is shown that the “viscous sublayer” becomes unstable, and forces appear on the streamlined surface, leading to the separation of bursts from the streamlined surface. The results obtained in the article confirm the experimental data: the fulfillment of the law of similarity of the burst formation frequency for supersonic gas flow. The results also confirm the realization of the resonant three-wave interaction of waves in the turbulent boundary layer, obtained in theoretical works.

Research implications. The results obtained in the article explain the mechanism of transition from laminar flow to turbulent flow at the nonlinear level, they complement and refine the theory of laminar -turbulent transition, previously studied within the framework of a weakly nonlinear approach.