bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of stiff differential equations of mathematical description of izomerization of pentane-hexane cut process
Authors: Faskhutdinova R I , Faskhutdinov A G , Enikeeva L V , Gubaydullin I M 
Published: December 2021

Abstract
This paper provides a brief overview of the existing definitions of a stiff system of differential equations. Further, on the example of the accepted scheme of chemical transformations of the catalytic isomerization process of the pentane-hexane fraction, the stiffness of the system of differential equations was studied. In the course of the work, a method for studying the direct kinetic problem for stiffness is presented. In the Matlab software, the results of solving a system of differential equations by five methods (solvers) were compared. The given method can be tried for solving other problems of chemical kinetics.
Parallel implementation of the primer search algorithm for loop-mediated isothermal amplification
Authors: Akhmetzianova L U , Davletkulov T M , Gubaidullin I M , Islamgulov A R 
Published: December 2021

Abstract
In the paper, the implementation of an algorithm of search for primers in a DNA sequence with a size varying between one nucleotide and multiple million nucleotides was discussed. This analysis was done within the objective of finding a set of six specific primers that are used for a conduction of the loop-mediated isothermal amplification (LAMP). For the fastest search result possible, a parallel search for the primer with the use of the Rabin-Karp Algorithm which enables the search for a primer’s entry in DNA sequence in each thread was proposed. A new software for search for primers was developed using Python with BioPython library which implements the algorithm.
Application of the genetic algorithm method in the problem of chemical kinetics of the oxidative regeneration process
Authors: Dubinets O V , Gubaidullin I M , Uzyanbaev R M , Vovdenko M K , Lapshin I G 
Published: December 2021

Abstract
Annotation. One of the main problems in chemical kinetics is the establishment of the mechanisms of complex chemical reactions. The inverse problem of chemical kinetics is understood as the determination of the dependence of the concentration of the participating components on the basis of experimental data obtained from a laboratory installation for the oxidative regeneration of coked catalysts. One of the main methods used in inverse problems the genetic algorithm. The algorithms considered in the article make it possible to determine the values of the rate constants of the considered chemical stages.
Parallel algorithms for solving diffusion-convection problems on a multiprocessor computer system using hybrid MPI / OpenMP technology
Authors: Atayan A , Dolgov V 
Published: December 2021

Abstract
The paper deals with the mathematical models, algorithms and software for mathematical modeling of coastal systems’ water pollution spreading dynamics under various unfavorable phenomena of natural and artificial genesis, developed for high-performance cluster systems. Methods for partitioning the computational domain for solving diffusion-convection problems have been developed, which allow for efficient parallelization of a computationally complex modeling problem, taking into account the architecture of the multiprocessor system used. The developed mathematical models are based on high-precision models of hydrophysics and hydrobiology and take into account the peculiarities of water systems in the south of the Rostov region, as well as factors of hydrobiological dynamics such as microturbulent diffusion and advective transport in various directions, mechanisms of primary and secondary pollution of coastal systems, taking into account currents. The paper presents algorithms for solving a simulated problem based on MPI parallelization technology, as well as based on mixed MPI + OpenMP technology. Numerical experiments have been carried out and the two technologies efficiency comparison has been made in the conditions of computing cluster used.
Processing and assimilation of observation data for the hydrodynamics model of the Black Sea and the Sea of Azov
Authors: Zakharova N B , Sheloput T O , Lezina N R , Shutyaev V P , Parmuzin E I , Agoshkov V I 
Published: December 2021

Abstract
This work is aimed at using the marine data of the Shared Use Centre (SUC) “IKI-Monitoring” in the variational assimilation procedures of the Informational Computational System (ICS) “INM RAS - Black Sea”. SUC “IKI - Monitoring” is a tool for obtaining remote sensing observations on the Earth state. In the paper observation data information is given, data processing procedures are described, algorithms for the assimilation of the information received and several specific features of the numerical model used are presented. Results of the variational assimilation of two sets of observation data are presented and discussed. Numerical experiments have confirmed the possibility of using incomplete data from satellites in the problems of modelling the sea area.
Two-dimensional mathematical model of autowave process in thin surface layer of liquid dispersed nanosystem (magnetic fluid)
Authors: Chekanov V , Kovalenko A , Diskaeva E N , Kirillova E 
Published: December 2021

Abstract
In this work, a two-dimensional mathematical model of an autowave process taking place in a thin near-electrode layer of a magnetic fluid is constructed. The model is represented by a boundary value problem, which consists of a solution domain, a system of equations, initial and boundary conditions. The mathematical model is implemented in the COMSOL Multiphysics physical process modeling system. Comparison of the results of the numerical solution with experimental data prove the adequacy of the developed model.
Simulation of control and stabilization of the lubricant-coolant flow
Authors: Gladckih D , Studennikova S 
Published: December 2021

Abstract
The subject of the research is a control system of coolant supply. The results of system simulation in MathLab application program package for solving problems of technical calculations are presented and the analysis of transients is carried out. Reliability and productivity of a machine tool module depends on the quality of coolant supply control. This problem is actual for CNC machines, used for drilling holes with hard-alloy drills. of cutting fluid through the cutting zone depends on the state of chips in the drill hole channels. In the article the simulation of pump control as a function of changing flow rate is performed. The conclusion of the conducted research is the proposed model of the system of supply and flow of lubrication-cooling fluid, which allows analyzing the performance of the object under study.
Mathematical modeling and multiobjective optimization complex catalyst hydroalumination reaction of olefins with diisobutylaluminium hydride
Authors: Koledina K F , Gubaydullin I M , Koledin S N 
Published: December 2021

Abstract
A mathematical model for the catalyst hydroalumination reaction of olefins with diisobutylaluminium hydride has been developed. In solving the direct kinetic problem applies multi-step method Gere variable order. When solving systems of ordinary differential equations in chemical kinetics, it is necessary to fulfill the balance relations at each sampling point. That ensures the fulfillment of the law of conservation of matter and the convergence of the numerical method. For the catalytic reaction of hydroalumination olefins in the presence of the organoaluminum compound diisobutylaluminum hydride, the problem of multicriteria optimization reaction conditions was solved based on a detailed kinetic model. The solutions found make it possible to optimally select the reaction conditions to achieve the maximum yield of target products, which can be based on the subsequent introduction of the laboratory reaction into production.
Mathematical model of shallow water self-purification process
Authors: Sukhinov A I , Belova Y V , Nikitina A V , Chistyakov A E 
Published: December 2021

Abstract
The paper covers the model of shallow water self-purification processes. The proposed mathematical model of biological kinetics is based on a system of non-stationary convection-diffusion-reaction equations with nonlinear terms, taking into account the water flow movement, gravitational sedimentation of impurities, microturbulent diffusion, and the detritus decomposition as a result of activity the aerobic and anaerobic bacteria. Discretization is performed on the basis of a linear combination of central and Upwind Leapfrog difference schemes, which makes it possible to increase the solution accuracy of biological kinetics problem at large values of the grid Péclet number (Peh > 2). To solve high-dimensional SLAEs, a modified alternating-triangular method was used.
Modelling vibrations of axial piezoelectric generator with active base
Authors: Haldkar R K , Parinov I A , Cherpakov A V , Shilyaeva O V 
Published: December 2021

Abstract
Modelling of an axial-type piezoelectric generator (PEG) is considered. PEG is an integral part of the system for converting mechanical vibration energy from the environment into electrical energy. The energy generator has an axial type of the configuration of elements, aimed on using bending and compressive loads simultaneously on piezoelectric elements. The base of the generator is made as an active pinching. A feature of PEG is that the generator has two types of piezoelectric elements: (1) elements located on the substrate in the form of a bimorph and (2) piezoelectric elements of a cylindrical shape, fixing the generator base, located on the same axis. PEG has a symmetrical structure about the center of proof mass. The results of modal and harmonic analysis of vibrations are given for vibration excitation of the PEG base in a certain frequency range. The analysis of the output characteristics is given.
First integrals of the system “platform with pendulum” and controlling of it
Authors: Bratishchev A V 
Published: December 2021

Abstract
The problem of controlling the movement of a movable platform with a hinged fixed pendulum is considered. This pair is interpreted as a system of stationary connected points one of which moves freely in a horizontal plane. In the first problem, a control is synthesized that ensures the movement of the platform in a limited area under any initial conditions. In the second problem, a control is synthesized that stabilizes the oscillations of the pendulum in a given fixed vertical plane relative to the suspension point. For the problem of control synthesis, the first integrals of a free system are found and used in the article.
Mathematical model of the influence of the rheology of lubricating compositions on the safety of rolling stock movement
Authors: Pinevich Elena , Lazarev Yuriy , Bolgarov Nikolay , Altynov Dmitry , Fatyushin Yuri 
Published: December 2021

Abstract
The article deals with the search for rational and balanced solutions to ensure maximum safety of rolling stock movement, taking into account the minimization of costs and technical measures. The paper presents a mathematical model for calculating the effect of rheological characteristics of lubricants on the service life of heavy-loaded friction units of rolling stock. The scheme of interaction of a wheel with a rail at a single-point contact is presented in the form of contacts of two cylinders of infinite length. The results of numerical analysis of the found analytical dependences of the influence of the plasticity parameter on the coefficient of friction, the influence of the plasticity parameter on the supporting force created by the lubricant layer during the movement of surfaces are presented. The influence of the coefficient of friction on the safety of rolling stock movement in the curved sections of the track is established.
Comparison of the design features of an electromechanical converter with a discrete secondary part with the classical installation options
Authors: Kuimov D N , Minkin M S 
Published: December 2021

Abstract
In the present article, devices with a discrete secondary part are considered, which act as means of intensifying many technological processes of mixing and dispersing materials. In the classic version, the device has a number of disadvantages. To eliminate the shortcomings, the design of an electromechanical converter with a discrete secondary part was developed, which differs from the classical version by a magnetic system capable of implementing the process of controlling the movement of a large set of ferromagnetic elements along a pre-developed trajectory.
Process fluid as a technological system element of vibro-impact parts processing
Authors: Prokopets G , Mordovtsev A 
Published: December 2021

Abstract
Vibro-impact processing refers to finishing processing methods, which largely determine the operational part properties. It is shown that the parameter optimization of the vibro-impact processing is a very promising area of improving the part quality and reducing their manufacturing cost.One of the most important technological system elements is the process fluid. As a result of the priory information analysis, factors that determine the parameters of the vibro-impact processing were identified.Because of theoretical studies, the process fluid parameters and flushing mode influence degree on the process parameters and treated part quality indicators was determined. The process fluid is presented as a set of unit volumes that form an elastically deformable matrix. The necessary list of initial data for determining the maximum allowable process fluid amount in the mass load volume has been identified.The dependence for determining the minimum required process fluid volume is presented. A complex parameter that characterizes the change in the load mass volume in one oscillations cycle, together with the working chamber oscillation frequency and the process fluid fluidity, which determine both the fluid flow process nature (turbulent) and the flow rate inside the load mass is proposed. Based on the complex parameter, the load mass flushing speed is determined. It is shown that at this stage, the numerical value of the parameter can only be determined experimentally. Its theoretical definition is a promising area of further research.
Investigation of the boundary layer zone with an aerodynamic flow around an axisymmetric spindle-shaped body for solving conjugate problems of heat and mass transfer
Authors: Novoselova T , Tolmacheva L , Palii A , Akopdjanyan J 
Published: December 2021

Abstract
The article discusses the possibility of calculating the thickness of the boundary layer when flowing around an axisymmetric spindle-shaped body without using empirical similarity coefficients. For this, the use of physical analogy of processes is proposed. The necessary flow conditions are described. The two-dimensional Laplace equation is solved for the near-surface region of the laminar flow around the body, obtained by rotating a curve of a given shape. When solving the problems of conjugate heat transfer, the regularities of the interaction of the flow with the body surface are taken into account, which, as a result, is reduced to the joint solution of the boundary layer equations describing the flow field and the heat conduction equations describing the propagation of temperature fields inside and outside the body. In view of the complexity or impossibility of the analytical solution of such problems, it is customary to resort to numerical methods for solving these equations. Even the numerical solution of the conjugate heat transfer problem is associated with a huge number of calculations, the availability of computing power and significant time costs. Therefore, it is customary to solve such problems in a quasi-stationary approximation, which imposes certain restrictions on the scope of application
On extending the life of nuclear reactors
Authors: Kramskoi A V , Lyudmirsky Y G , Zhidkov M E , Kramskaia M I 
Published: December 2021

Abstract
To extend the service life of nuclear reactors, witness samples from the shells of the core of the reactor vessel are placed in their core. According to the requirements in force in the industry, the reference samples are loaded into the reactor plant unloaded up to the design stresses. This can lead to a biased assessment of the possible extension of the reactor’s life. In connection with the above, in order to assess the mutual influence of operating factors and the stress-strain state of the base metal and welded joints on embrittlement, the reference specimens must be loaded with a force that causes the maximum possible stresses in the specimens during the operation of the reactor. On the basis of domestic and international experience, a test procedure, design and loading scheme for compact witness samples are proposed for modeling and assessing the mutual influence of operating factors and stress-strain state on the object under study (VVER power reactor vessel). For VVER RPVs, the duration of the additional service life should be confirmed by the justification that by the end of the additional service life, the fracture toughness values of the base metal and metal of the welded seams located in the irradiation zone will allow without destruction to withstand all operational and emergency loads, as well as loads at hydraulic tests.
Modeling of protective plasma spray ceramic coating made of clad powder mixture
Authors: Tsareva I , Krivina L , Berdnik O 
Published: December 2021

Abstract
To solve the problem of increasing the adhesive-cohesive strength of plasma multifunctional coatings used to protect parts of power and mechanical engineering equipment components from wear and corrosion, a ceramic coating of the “Al2O3 - Ni” system, obtained from a powder mixture based on corundum clad with nickel, is proposed for use and studied. The coating was applied by high-energy plasma powder deposition (on the “Thermoplasma-50” installation) to the intermetallic sublayer of the “Ni-Co-Cr-Al-Y” system. The aim of this work was to study the micro structure and phase composition of the powder mixture of oxide ceramics clad with a refractory metal component (nickel), as well as the plasma coating formed from this powder material. According to the results of the research, it was found that the powder mixture clad with nickel has a multiphase composition (Ni+l-Al2O3+r-Al2O3), a spherical morphology of particles. From this powder material, a coating with a phase composition (Ni+L -Al2O3+J ’-L J u Ll) is formed, characterized by a layered microstructure with a columnar structure of oxide grains and nickel interlayers. The coating has high hardness and adhesive-cohesive strength, low coefficient of friction and is recommended for protection against wear of energy and mechanical engineering parts.
Modeling features of the technological process of forestry machines parts strengthening by the method of gas-thermal spraying
Authors: Kretinin V , Teppoev A , Sokolova V 
Published: December 2021

Abstract
The efficiency of the working bodies of tillage forestry machines is determined by the sharpness of their soil-cutting elements. The purpose of the study is to substantiate the modes of the technological process of strengthening and recovery of cutting working forestry machines by the method of gas-flame spraying of wear-resistant coatings to increase their wear resistance and preserve the blade sharpness by implementing the self-sharpening effect, which allows increasing their life by 2-3 times. Technical and economic indicators of the gas-flame spraying process, as well as the scope of its application, depend on how well the technological modes of the spraying process are selected. The relevance of the topic is due to the need to increase the durability of tillage tools by strengthening their surfaces treatment. Such effective methods include the technology of recovery and strengthening of the working bodies of tillage machines using the technology of gas-flame spraying. In this regard, the issues of conducting research have become particularly relevant: to identify the relationships of technological parameters during the gas-flame application of wear-resistant coatings; to change the strength characteristics of the material of parts during their recovery, providing the necessary reliability and durability.
Effect of roughness on the bond strength of decorative coating applied by cold gas-dynamic spraying
Authors: Dudnik M , Gordin Yu 
Published: December 2021

Abstract
The adhesion strength of joints obtained by cold gas-dynamic spraying (CGDS) on cast iron base has been investigated. It is known that corrosion resistance of CGDS coatings is largely determined not only by the nature of the sprayed material, but also by its adhesion properties. This paper is a method for predicting the adhesion strength of a protective and decorative coating, which is a useful tool for engineers when studying the effect of certain technological parameters on the adhesion strength of cold gas-dynamic spraying. The results of an experimental study of pretreated surfaces and powder materials are presented. The optimum heating temperature was determined and a choice of material and method of substrate processing which ensures maximum adhesion strength under given technological conditions was substantiated. It was shown that the temperature of heating of the product surface essentially influences the adhesion strength of the coating. Besides the quality of the preprocessed surface is one of the factors providing the coating adhesion strength to the substrate. The dependences of the influence of the temperature of heating of the sample and the roughness of the surface on the adhesion strength are presented. The use of cold gas-dynamic spraying as a method providing high strength properties of copper and zinc protective-decorative coatings is proved.
Increase in productivity and quality based on the control of thermodynamic processes during deep profile grinding of the gas-turbine engine blade
Authors: Makarov V , Nikitin S , Pesin M , Karmanov V , Norin O 
Published: December 2021

Abstract
The article provides the system of interaction of dynamic processes during deep profile grinding of complex profiles on a multiaxis machine, the influence of dynamic processes on the quality of the surface layer, the endurance limit of the gas-turbine engine blade. The method presented allows to assign corresponding grinding modes based on the forecast of the dynamics of elastic, thermal and working processes in a thermomechanical system. This technique allows to control the process of deep profile grinding to achieve the specified parameters of surface quality, the endurance limit of the blade and increase process efficiency.