The article presents a numerical simulation of energy separation (thermal stratification) in a Leontiev tube, conducted using STAR-CCM+ software. The study focuses on a comparative analysis of two different tube designs, each intended to create temperature differences in gas flows. The simulation revealed that the supersonic flow passing through the tube significantly increases in temperature at the outlet, while the subsonic flow, on the contrary, shows a noticeable decrease in temperature. Detailed profiles of gas velocity and temperature are provided for both designs, demonstrating the effectiveness of each Leontiev tube variant in creating distinct areas of gas with different temperatures without the need for additional external heat exchange. The results obtained are of practical significance for improving the efficiency of gas distribution stations, enabling more effective management of thermal flows and preventing the formation of gas hydrates, as well as for use in other technological processes where temperature separation in flows is required without external heating or cooling.

Keywords: Leontiev tube, numerical simulation, STAR-CCM+, thermal stratification, gas flow

Automatic classification of electrocardiogram signals will allow providing timely medical care to patients when providing first aid. Neural network models of electrocardiogram signal classification, including the stage of preliminary signal processing, allow increasing the accuracy of classifying electrocardiograms into a particular category of arrhythmia. The paper presents a computational method for preliminary processing of electrocardiogram signals, including noise reduction using discrete wavelet transform and extraction of morphological features using frequency analysis methods. The results of modeling the classification of 12-channel electrocardiogram signals using the stage of their preliminary processing showed an increase in classification accuracy by 23.2% compared to classification without preliminary signal processing.

Keywords: electrocardiogram signal classification, long-term short-term memory neural network, metadata, signal preprocessing wavelet transform, spectral analysis, PhysioNet Computing in Cardiology Challenge 2021

Amid the climate crisis and rising energy costs, the need for improving energy efficiency is becoming increasingly critical. Governments aim to reduce carbon dioxide emissions, while businesses seek to optimize energy expenses. The digitalization of the energy sector and the adoption of Internet of Things (IoT) technologies create favorable conditions for the application of artificial intelligence (AI) in energy consumption management. This article provides an overview of AI technologies and their application in energy consumption management, using an ice rink as a case study. The energy consumption data collected from a real-world facility is analyzed, and methods of neural network modeling of time series for forecasting and optimizing management are examined. The results of the modeling are presented, demonstrating the potential of predictive algorithms in reducing energy costs and improving the operational efficiency of ice rinks.

Keywords: global warming, energy consumption, energy efficiency, digitalization, Internet of Things, artificial intelligence, energy management, machine learning, deep learning, time series, predictive algorithms

The article addresses the issue of determining the ultimate eccentric compressive longitudinal force from an external load acting on a compressed reinforced concrete element. The calculation assumptions are adopted in accordance with the current code of practice SP 63.13330.2018. The transformation of the initial formulas given in this code allowed the explicit solution of the cubic equation with respect to the compressive longitudinal force without the need for iterative calculation methods. The solution thus obtained can be employed in the design process to determine the optimal section dimensions.

Keywords: reinforced concrete, excentric compression,ultimate forces

This article presents the results of simulation of the stress-strain state of the base under dies with a stepped shape of the bottom of the support. Numerical modeling was performed using Plaxis 2D. The results of modeling stamps with different angles of descent of steps with an equal surface area of ​ contact with the soil showed the dependence of stresses and displacements on this parameter.

Keywords: effective foundation, shallow foundation, columnar foundation, die with convex support surface, stepped sole, soil mechanics, settlement of foundations

The article considers modeling of nonlinear electrical conductivity of a biological cell using the equivalent circuit method. The paper proposes a nonlinear model of the electrical conductivity of a biological cell based on the use of nonlinear active and passive elements. The main mechanisms that determine the nonlinear nature of the electrical characteristics of a cell, including the phenomena of cell membrane polarization, are considered. To verify the model, a comparison of calculated and experimental data on the electrical parameters of biological cells is carried out. It is shown that the use of a nonlinear equivalent circuit allows more accurately reproducing the real behavior of cells in a wide range of applied voltages. The presented modeling technique can be applied to study the electrical properties of various types of biological cells, as well as to develop new electronic devices interacting with living systems. The article considers a complex nonlinear dependence of the electrical conductivity of a biological cell on voltage, which is caused by the interaction of two ion channels with different characteristics and resonance effects created by a series circuit. The method of equivalent circuits made it possible to create a single model that combines components responsible for ionic conductivity, capacitive properties of the membrane and resonance phenomena associated with the presence of electropores.

Keywords: mathematical modeling, equivalent circuit method, software, biological cell, computational research, electrical conductivity

The article studies the possibility of using the continuous form of the maximum consistency method when constructing regression models to calculate the forecast values of the air transport passenger turnover indicator in the Russian Federation. The method under study is compared with classical methods of regression analysis - least squares and moduli. To assess the predictive properties of the methods, the average relative forecast error and the continuous form of the criterion for the consistency of behavior between the calculated and actual values of the dependent variable are used. As a result of the analysis, a conclusion was made about the possibility of using the method under study to solve forecast problems.

Keywords: least squares method, continuous form of the maximum consistency method, modeling, passenger turnover, air transport, adequacy criteria

The article examines the application of the method of mathematical planning of an optimal experiment in determining the strength characteristics of reinforced soils. For the analysis, a multicomponent soil system was studied, consisting of unsalted and saline soils reinforced with bitumen with cement additives and surfactants. During the planning of the experiment, factors affecting the strength characteristics and their levels, as well as the intervals of variation of factors, were determined. As a result of solving the problem, mathematical models of adhesion and angle of internal friction of reinforced soils were obtained. Based on the obtained regression equations, the main conclusions were drawn.

Keywords: stabilized soils, complex soil strengthening, experiment planning, complete factor experiment, mathematical model, regression equation

The article is devoted to the development of a mathematical model and a software package designed to automate scientific research in the field of financial industry news analysis. The authors propose an approach based on the use of graph theory methods to identify the most significant scientific hypotheses, the methods used, as well as the obtained qualitative and quantitative results of the scientific community in this field. The proposed model and software package make it possible to automate the process of scientific research, which contributes to a more effective analysis of it. The research results can be useful both for professional participants in financial markets and for the academic community, since the identification of the most cited and fundamental works serves as the starting point of any scientific work.

Keywords: software package, modeling, graph theory, news streams, Russian stock market, stocks, citation graph

The article presents the state of technology of websites for designing robots with artificial intelligence. The image of a modern technical site-book as a place for the development of artificial intelligence applications is considered, the possibility of executing algorithms from the page to ensure the connection of robots with real and virtual objects is shown.

Keywords: mathematical network, technical website-book, artificial intelligence, algorithms executed on the website-book, network development of robots

The paper presents a brief overview of publications describing the experience of using mathematical modeling methods to solve various problems. A multivariate piecewise linear regression model of a steel company was built using the continuous form of the maximum consistency method. To assess the adequacy of the model, the following criteria were used: average relative error of approximation, continuous criterion of consistency of behavior, sum of modules of approximation errors. It is concluded that the resulting model has sufficient accuracy and can be used for forecasting.

Keywords: mathematical modeling, piecewise linear regression, least modulus method, continuous form of maximum consistency method, steel company

The subject of this article is the development of a behavior pattern with AI elements for an opponent bot in the single-player game Steal Tower. The essence of which is to collect resources to build a tower faster than opponents. To create the illusion that the same people are playing against the player, an imitation stochastic model based on the Monte Carlo method for Markov chains has been developed. Based on the results of its tests, balanced system parameters were determined, which are embedded in the behavioral pattern of the bot, which is implemented using the Enum AIStates enumeration consisting of five states: Idle (inactivity), GoTo (movement) and GoToWarehouse (return to the warehouse), Win (victory), Loose (scoring). Each of them has developed functions for the optimal behavior of the bot given in the article. So for the GoTo state, functions have been created that analyze the benefits of different types of behavior: steal or collect, or walk to the warehouse or to the tower.

Keywords: game intelligence, behavioral pattern, live world emulation, bot behavior scenario, state structure, Markov chains, Monte Carlo method, simulation model, Unity environment, C# language

The validity of analytical models of the process of one-parameter selective assembly of two elements was evaluated by comparison with the results of simulation modelling. A series of machine experiments including one-factor and two-factor experiments were carried out. At the accepted levels of variation of factors, the confidence interval of the probability of yield of good products from the initial population of elements that did not pass sorting was determined using Student's criterion at the given level of significance and number of degrees of freedom. Comparison of the simulation results revealed the facts of reaching the specified process indicator, determined by the analytical model, for all experiments within the confidence intervals and the presence of relatively small deviations from their centres.

Keywords: selective assembly, analytical model, simulation model, measurement error, simulation results

A new numerical method for calculating weather conditions has been developed for airborne radar systems for Arctic purposes. Based on the numerical method obtained in the study, software was developed that takes into account various models of electromagnetic wave propagation in various weather conditions. The results of calculations for estimating the detection range of dangerous weather conditions are presented. This assessment indicates that the threshold for detecting adverse weather conditions can be reduced. The basis for lowering the threshold without deteriorating the resulting probabilities of correct detection and false alarm is the fact that the occurrence of cases of false detection is possible only when a certain total extent of difficult weather conditions is reached, which can already be considered dangerous for the flight. The features of the formation of reflected signals from Arctic rain clouds, turbulence over a snowy desert and wind shear are considered. It is shown that all of them are characterized by lower radar reflectivity, therefore the resulting detection ranges are less than those that can be obtained at more southern latitudes, but at the same time they are sufficient for the navigation of UAVs or small aircraft.

Keywords: airborne radar, numerical methods for assessing weather conditions, weather navigation in polar latitudes, UAV navigation, hazardous weather formation

The article is devoted to the study of the flow rate depending on the pressure in the gas supply system of the plasma head. The problem was solved by conducting a computer experiment with subsequent verification of the results by a full-scale experiment. The laboratory plasma installation MAK-10 assembled on the basis of the IMET UB RAS, used in the processes of coating, powder production and surface modification of parts, was simulated. The computer experiment was carried out using the SolidWorks Flow Simulation software package. As a result of the work performed, the distribution of the flow rate along its axis was demonstrated during the operation of the plasma installation with a pressure in the gas supply system of 0.1; 0.2 and 0.3 MPa. Recommendations for conducting coating, powder production and surface modification processes have been developed, which have practical benefits for consumers of process equipment.

Keywords: mathematical model, flow, velocity, pressure, plasma method, powder production, coating, surface modification

The study of the influence of the number of layers of glass composite pipe on dynamic loading, including operation in seismically active areas, is conditioned by compliance with the requirements of the latest documents in the field of construction standard control. Mechanical characteristics of glass composite pipe depend on elastic and strength properties of glass fibre, silica sand and binder, their ratio and bonding strength between layers. The key parameter of glass composite pipe compliance with the given requirements is ring stiffness. The strength of the composite material is determined using the rule of mixtures. The properties of the glass composite pipe using the rule of mixtures are determined. The influence of the number of layers of glass composite pipe on its elastic-strength properties is considered. The experiment with uniaxial compression of the pipe link is simulated in Midas GTS NX software package. The maximum load at which the sample reaches 5% deformation was determined. According to the results of the study, it was obtained that the best elastic-strength and operational properties have three-layer composite structure.

Keywords: glass composite pipe, layer scheme, earthquake resistance, continuous winding method, elastic-strength properties

The general characteristics of the innovative RAID-60 data storage system, which combines the best aspects of RAID-6 and RAID-0E technologies, as well as the reliability model of this data storage sys-tem, are presented. The main purpose of this connection is to provide outstanding performance with maximum data redundancy. The arti-cle discusses in detail the structural analysis, advantages and various scenarios for the use of the specified RAID-60 data storage system and the proposed model of its reliability. An important aspect is also the comparison of the RAID-60 system with other widespread vari-ants of data storage systems, such as RAID-0, RAID-1 and RAID-5, as well as with the reliability models of these systems. Particular at-tention is paid to the formula that allows you to calculate the average operating time to failure of a disk array. Also, for completeness of the analysis, attention is paid to plotting the probability of a RAID-60 failure (P(t)) over time (t). This graph is an important tool for visu-alizing the dynamics of reliability of data storage systems.

Keywords: RAID-60, reliability, disk array, data redundancy, manufacturer, parity blocks, data storage

Algorithms and structures of spatial partitioning kd-tree, BVH are considered and studied in relation to the problem of modeling the flow of air around a body of complex shape. The use of these algorithms makes it possible to significantly reduce the computation time when searching for collisions of air particles with each other and with a streamlined body.

Keywords: collision detection, computational geometry, data structures and algorithms, kd-tree, BVH

The paper offers one of the variants of construction and use of fuzzy query mechanism for modeling of telecommunication network state estimation. The modular architecture of the application is considered in detail, the logic of calculating the degrees of belongingness to each term of the selected linguistic variables is described, the stages of the algorithm of work with the mechanism of fuzzy queries are given.

Keywords: fuzzy query, search, membership function parameters, state estimation modeling, database, knowledge, fuzzy classification

The article is based on the results of a scientific study on modelling the operation of the system ‘foundation - ground mass’ of a special type of deep foundation - gantry piles in conditions of ground mass during the construction of the overpass of the M-12 ‘Vostok’ highway. Gantry inclined piles are designed to transfer more load to the foundation than traditional vertical piles. The purpose of this study is to select the angle of inclination of gantry piles for overpass support on the basis of mathematical modelling. The scientific novelty consists in the selection of the gantry pile foundation design for the support of a motorway overpass by mathematical modelling.

Keywords: gantry piles, deep foundation, overpass, modelling, finite element method, soil massif, stresses, deformations, stanchion, foundation-soil massif system

This paper is devoted to optimization of surface acoustic wave bandpass filters with apodized interdigital transducers (IDT). Iterative Parks-McClellan algorithm is applied to estimate the apodization coefficients of the IDT fingers. A family of corresponding subroutines is developed in the Matlab mathematical package. The simulation results of the SAW filter optimized design are illustrated. For the refined estimation of the filter frequency response COM-based P-Matrices are employed. The results obtained in this study constitute a set of tools for the practical calculation of apodized IDTs and filters according to a given specification. Subroutines implementing COM-based P-Matrices can be utilized as part of programs for frequency-selective SAW devices design.

Keywords: acoustoelectronics, apodization, approximation, interdigitated transducer, impulse response, surface acoustic wave, optimization, piezoelectricity, filter, frequency response

This paper considers the development and training of a neural network model for the identification of the species and quantitative composition of pollen, which will subsequently be used to determine the botanical origin of honey and quantitative calculations of pollen grains contained in a certain mass of honey. The main purpose of the study is to create a model that can effectively distinguish the morphology of pollen grains present in honey, determine their quantitative and qualitative composition, which will improve product quality control, as well as identify its botanical and geographical origin. For this purpose, similar works on pollen classification were analyzed. Pwtorch was chosen as the framework for creating a neural network model, which provides the possibility of detailed configuration of the model. The result of the work is a trained model capable of classifying pollen grains.

Keywords: neural networks, classification task, pollen classification, convolutional neural networks, PyTorch

A numerical study of heat transfer and hydrodynamics in plate heat exchangers with corrugated fins was carried out. The effect of corrugation pitch on heat flow and pressure drop was studied. The study was carried out using computational fluid dynamics in the ANSYS software package (v. 19.2). The results of the study showed that increasing the corrugation pitch from n = 5 to n = 9 leads to an increase in heat flow of 10.83% and a pressure drop of 28.30%.

Keywords: plate-fin heat exchanger, corrugated fins, heat transfer, hydrodynamics, numerical study, calculation, heat flow, pressure drop, energy efficiency, cooling system

The use of small drones to detect urban targets such as vehicles at low altitude in cities has gradually become a mainstream means. In view of the existing problems of low detection accuracy of single-mode detection network caused by visible light detection, inability to work at night and blurred edge of infrared detection targets in actual scenes, In this paper, a multi-modal UAV detection algorithm based on image fusion and deep learning network is proposed. Firstly, based on DUT-VTUAV visible-infrared registration data set and TIF image fusion algorithm, multi-mode fusion data set is constructed. Secondly, by comparing the detection accuracy, speed and number of parameters of the existing YOLO series network, the lightweight network YOLO v5n which is most suitable for the mobile deployment of UAVS is selected. Finally, a multi-modal fusion detection algorithm is formed by combining image fusion algorithm and target detection model. Comparative experiments on vehicle data sets show that compared with single-mode detection, the detection accuracy of the proposed algorithm is effectively improved, with mAP up to 99.6%, and a set of visible-infrared image fusion detection can be completed within 0.3s, which has high real-time performance.

Keywords: target detection, YOLO, multimodal fusion, data fusion, TIF algorithm

A semi-Markov stationary model of operation of measuring instruments installed on complex technical systems is developed, which allows modelling the process of metrological maintenance of measuring instruments at combined verification and operational automated condition control. The results of modelling are presented.

Keywords: semi-Markov model, measuring instrument, verification, operational automated state control