Arkady N. Soloviev’s research while affiliated with Crimean Engineering-Pedagogical University and other places

This article is devoted to the further development of a viable technology for low-temperature cryopreservation of reproductive cells of sturgeon fish using acoustic–mechanical fields and intelligent control of the freezing process. Before vitrification begins, the piezoactuator acts on a mixture of cryoprotectant and reproductive cells. This promotes intensive mixing of the cryoprotector and its diffusion through the cell membrane. When vitrification is carried out directly, a phase transition phenomenon is observed, accompanied by crystal formation. This article presents a new mathematical model describing this process as developed by the authors. The corresponding boundary conditions are formulated. Numerical experiments were carried out using the finite element method. It has been established that during vitrification without the use of a cryoprotectant, a sharp temperature jump is observed at the front of the crystalline formation boundary. The use of a cryoprotectant leads to a slowdown in the process of crystal formation, that is, to a weakening of the effect of one of the most important cryoprotective factors. The comparison with full-scale experiments showed qualitative agreement with the experimental results, which indicates the adequacy of the proposed model. The results obtained can be used in the future during the vitrification process and the evaluation of the quality of cryofreezing. The application of a new methodological approach to methods of long-term preservation at low temperatures of the genetic and reproductive material of hydrobionts using acoustic and mechanical effects and an intelligent control module opens up great opportunities for the creation of new cost-effective biotechnologies that make it possible to make the transition to a new type of aquatic farms, increase the stability of aquaculture, in general, to make environmental protection measures to save rare and endangered species more effective.

This study focuses on the advancement of new techniques for cryopreservation of reproductive cells at low temperatures, including sturgeon fish. The approach is based on smart freezing process control. To ensure cryoprotectant and reproductive cells are not damaged prior to vitrification, a piezoactuator is used to stir the mixture. This technique facilitates the intensive mixing of cryoprotectant, promoting the diffusion of the substance through the cell membrane. During direct vitrification, researchers observe a phase transition phenomenon in the presence of crystal formation. This study constructs a mathematical model to investigate this process while comparing numerical experiments to in situ experiments. The results obtained have implications for selecting optimal parameters required for the low-temperature preservation of fish reproductive cells.

In order to further develop and improve the university program for the training of mechanical engineers, the paper considers the fundamental changes in the curriculum for the training of bachelors in the program “Applied Mechanics”, profile “Software Systems of Computer Engineering”. For the training of specialists in the environment of the T-university, a new major developed for this educational program is described.KeywordsBachelorUndergraduateApplied MechanicsComputer Engineering Software SystemsMajorEngineering EducationTeaching

In this chapter, based on the finite element method, a three-dimensional stationary problem of excitation of harmonic waves in the actuator-panel system is modeled. The calculations were performed using the harmonic vibration analysis module. Two types of transducers were considered: directional and omnidirectional. Isotropic and orthotropic types of plate materials have been studied. The ultrasonic wavefront response is analyzed for intact and damaged cases. Emphasis is placed on the ability of harmonic analysis to provide correct data on direction-dependent wavefront characteristics. When comparing the obtained results with other published ones, it should be noted that the presented methodology is acceptable for the rapid formation of the database in the first assumption.KeywordsActuatorWedgePanelCFRPOrthotropicWaveHarmonicAttenuationDirectivity

In order to develop a new technology for low-temperature preservation of fish reproductive cells, and sturgeon fish in particular, mathematical modeling of acoustic impact on biological objects has been performed. A mathematical model of cryoprotectant diffusion through the reproductive cell membrane is constructed. It is assumed that a special piezoactuator creates an acoustic field in the cryoprotectant. By virtue of this, the corresponding velocity field of the environment is assumed to be set. The resulting boundary-value problem is solved numerically using the finite element method.KeywordsDiffusionCryoprotectantPiezoactuatorReproductive cellSturgeon fish

Porous piezoceramic shows better electromechanical properties than full-bodied in some cases, including longitudinal vibrations. This effect is possible due to the lower reduction of piezo properties compared to elastic properties with growth of the porosity percentage. In this paper we model shear vibrations of piezoelectric transducers with different porosity. The goal of the research is to measure thedifference in electromechanical coupling coefficients (EMCCs) and output potential in the case of forced vibrations on the first shear mode. Effective materials properties of the porous ceramics were obtained with ACELAN-COMPOS finite-element software. The final element analysis of the transducer was performed with COMSOL Multiphysics software. As analyses showed, the EMCCs degraded with the growth of porosity, but the output potential value grew.KeywordsPorousPiezoelectricCompositesFinite element method (FEM)

The modeling and analysis the removal of metal process in centrifugal rotational processing of workpiece in abrasive medium are considered in this article. The single contact interaction process between abrasive particle and the workpiece surface is researched through three-dimensional modeling taking into account dry coefficient of friction. The contact interaction problem is solved through Ansys software and Archard code programmed to analyze the data. The removal of metal from the workpiece surface is researched when changing the technological parameters: friction coefficient, machining time, speed. The dependences between metal removal from the workpiece surface and technological parameters are constructed, from which reasonable parameters can be selected when machining the workpiece, allowing to achieve high accuracy. Experimental results have been confirmed by simulation results. Through this research, essential and important data sheets will be provided for actual production and testing activities. Consequently, time and money are saved in achieving the desired surface quality.

This article examines the static and dynamic deformation of the stem of an ear of wheat and of the individual grain. The purpose of the article is to determine the factors of influence on the ear of wheat to isolate the grain. Two stages of grain ripening are considered: in the early stage, the grain is attached to the spike by the stem; in the second, there is no stem, and the grain is attached to the ear by the scales. The ear fluctuations are considered within the Euler–Bernoulli bar theory. The developed model divides the study of the dynamics of the stem of an ear and the dynamics of the grain into two stages. The first stage studies the dynamics of the plant as a whole, while the second stage studies the dynamics of an individual grain in a moving system associated with the ear in bending and vertical fluctuation forms. The model of the ear and the grain fluctuation uses the mechanical characteristics of elastic bonds and elastic bodies, which are determined by spring stiffness, elastic moduli, etc. The results show that in the vertical forms of grain fluctuation, the frequency of fluctuation is much higher than in the bending ones. This article presents the natural fluctuation frequencies of grain at full ripeness and in the early phases of maturation, at which point it is released from the ear.

An intraocular lenses (IOLs) implanted in the eye is used to treat diseases such as cataracts or myopia. This chapter examines the problem of cataract healing while preserving the natural accommodation of the eye. The aim of this work is to model the system of IOLs, which has the possibility of accommodation, as well as the natural lens. The SpaceClaim CAD system was used for direct 3D modeling of an IOL with elastic haptic elements and the ANSYS Mechanical environment for creating a finite element mesh and a numerical model of deformations.

In the work mathematical and computer modeling the operation instrument, which is used in the operation to replace the lens are carried out. The tip of a lensotome, which is a hollow cylinder that vibrates axially is considered. Oscillations are excited by a piezoelectric element. A modal analysis of the structure is carried out, the frequencies of resonance, antiresonance and the coefficient of electromechanical coupling (CEMC) are found. An analysis of the values of this coefficient and natural modes of vibration allows us to select the operating frequency of the instrument, at which there is an effective conversion of electrical energy into mechanical and intensive movement of the lensotome tip end, which acts on the tissue of the lens during its fracture.