Aim: experimental study of the “crystal-liquid” phase transition in the temperature range from – 10°С до +25°С in a closed system with a “honeycomb” type structure with accumulation of water.

Methodology. Methods of acoustic emission induced by changes in the external temperature field are used. Under the influence of a changing temperature field, melting of ice crystals occurs inside the honeycomb structure, as a result of which discrete ultrasonic pulses are emitted, which are recorded by an acoustic emission installation for subsequent analysis. Heating is carried out in two ways: (1) by relaxing the temperature of cooled samples to room temperature values; (2) cooled samples receive additional, forced constant heating, thereby increasing the rate of temperature rise.

Results. The dependences of the amplitudes and activity (the number of acoustic emission pulses per unit time) of acoustic signals on time, as well as the frequency distribution of recorded ultrasonic pulses, were obtained. It is shown that as a result of forced heating, signals indicating an “ice-water” phase transition in the honeycombs most clearly appear.

Research implications. The conducted experiments show that the method of acoustic emission at insignificant variations of the temperature field allows to detect a defect in the form of moisture in a closed honeycomb structure.

Aim: to consider the process of emitting a sound wave (main mode) from a semi-infinite channel without a flange when the air inside and outside the channel is at rest, to develop a procedure for approximating the solution, which allows us to obtain the reflection and transformation coefficients of the main mode wave on the channel slice, as well as a directional pattern and spatial distribution of acoustic pressure outside the channel, and compare it with an accurate analytical solution.

Methodology. The solution of the problem is expressed in terms of the eigenfunctions of the continuous and discrete spectrum problem. The conditions of continuity of the solution on the channel slice are used as closure conditions.

Results. Approximate characteristics of sound emission from a channel without flanges are determined, bypassing the Wiener – Hopf procedure.

Research implications. The proposed procedure simplifies obtaining a solution compared to the Wiener – Hopf method, which, in the case of gas moving in the channel, makes it possible to link the sound generation process with the characteristics of the boundary layer on the channel walls.

Aim. On the basis of asymptotic and approximate theoretical methods for solving the system of kinetic Boltzmann equations for a shock compressed binary mixture of gases, analytical representations of the distribution functions of the components of the mixture are found.

Methods. Asymptotic and variational methods of mathematical physics were used.

Results. Asymptotic and approximate analytical expressions are found for the distribution functions of components of a shock-compressed binary mixture of gases. For a modification of the Tamm–Mott-Smith method known in the literature, the laws of conservation of mass, momentum and energy fluxes in an arbitrary section inside a shock wave are proved for the first time. Previously, there was no such proof in the literature. The importance of such a proof is due to the fact that when applying the classical Tamm–Mott-Smith method to binary mixtures of gases, it is impossible to ensure compliance with the conservation laws inside the shock wave front.

Research implications. The obtained analytical results are essential both for elucidating the conditions for accelerating the velocities of kinetic processes in the structure of shock waves, and for determining the optimal conditions for conducting appropriate experiments in shock tubes.

Aim. To reveal the differences in the dynamics of deoxyribonucleic acid (DNA) and its stabilizing protein on the surface of graphene, graphene oxide and in solution.

Methodology. Using the method of molecular dynamics in the all atom approximation, calculations of DNA bound to the DNA-stabilizing protein DPS (DNA-binding protein from starved cells) on the surface of graphene, graphene oxide and in solution were carried out.

Results. Based on the studies performed, it was shown that graphene substrates can affect the dynamics of proteins and DNA. In particular, they can limit the mobility of free protein regions, hindering their interaction with other molecules, and adsorb DNA, changing the structure of DPS – DNA complexes.

Research implications. The obtained data are of practical interest for researchers of the structure of biological molecules and their complexes on the surface of graphene substrates. Also, the data can be used to create bioinspired nanomaterials with desired properties. 

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 the modern object-oriented programming language and functional libraries was created, which allows to present the pixel structure of a visual image in a sound display format.

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).