Voronezh State Technical University

This study proposes a system dynamics (SD) approach to evaluate the long-term sustainability and economic feasibility of biofuels as an alternative to fossil fuels. A Python-based SD model will analyze diverse deployment scenarios. The analysis will incorporate variables such as feedstock types, policy frameworks, technological advancements, and investment rates. Environmental sustainability will be assessed through greenhouse gas (GHG) emissions, land and water use, and biodiversity impacts. Economic feasibility will focus on production costs, market dynamics, and return on investment (ROI). Sensitivity analysis will identify the critical parameters that influence outcomes. The research aims to provide actionable policy and investment recommendations by mapping trade-offs between biofuel deployment and interconnected systems (food, water, land). Results will highlight the optimal pathways for scaling sustainable biofuel production and identify key tipping points in the energy transition.

The properties of Cu/NC/D/Ni memristive structures with thin layers of (CoFe)x(SiO2)100–x nanocomposite (230 nm) and LiNbO3 dielectric (14–28 nm) are studied. It is shown that annealing the structures at 300°C for 10 min leads to increase in the ratio of the high-resistance state (Roff) to the low-resistance state (Ron). Heat treatment also increases the stability of resistive state. The increase of the LiNbO3 layer thickness increases in the values of Roff, Ron, and the resistive switching (RS) voltage of the structures to the low-resistance state. The structures exhibit stable multilevel RS in successive cycles of potentiation and depression, which, coupled with plasticity and a high Roff/Ron ratio, demonstrates the prospects of their use as synapses in the development of neuromorphic systems.

The work is devoted to the study of the factors of the working environment of rescuers of the explosive engineering unit of the emergency rescue service, taking into account the negative impact. The Emergency rescue service is designed to prevent natural and man-made emergencies and perform emergency rescue and other emergency operations in accordance with the tasks assigned by current legislation. The paper indicates the main types of work of rescuers: search and rescue operations, gas rescue operations, diving operations, blasting operations using explosive materials for industrial purposes. Data on environmental factors during explosive work by rescue bomb technicians are presented and recommendations for improving the safe performance of explosive work are proposed.

Statement of the problem. To automate and optimize the technological processes of forming a protective coating of pipe metal, it is advisable to develop a digital twin of the heat treatment process of the protective coating material made of rubber mastic (caouton) on the surface of pipe metal using induction heating. Results. The developed mathematical model of the temperature field distribution in a vulcanized caouton-based coating made it possible to establish optimal modes of heat treatment of rubber mastic on the surface of pipe metal during the structuring of the protective coating material, taking into account the influence of existing external influences on the technological process. Conclusions. The use of a digital twin of the vulcanization process of the protective coating of pipe metal made it possible to retrofit the heat generating unit with a programmable thermostatic device that allows generating optimal temperature conditions for vulcanization of caouton, which made it possible to automate and regulate the technological process of introducing thermal energy into rubber mastic for structuring caouton on the surface of pipe metal. As a result, a protective coating with maximum strength and performance characteristics was obtained.

This article examines the influence of electric motor parameters on the flight performance of a multirotor unmanned aerial vehicle (UAV), taking into account its intended use and operational characteristics. To optimally select a propeller and electric motor for the propeller–motor system, it is proposed to use experimentally measured propeller thrust characteristics and its energy performance as a rotational speed function. Equations approximating the obtained relationships allow us to identify the characteristics and patterns of mutual influence between the electric motor and propeller. A design methodology for the electric motor of the propeller–motor system of an unmanned aerial vehicle, taking into account its intended use and operating mode, is proposed.

Background. Implementation of scanning antennas for noise-immune communication systems and radar systems is an important and urgent task. One of the most promising methods of beam deflection is frequency scanning, which can be effectively combined with switching, which will provide full-azimuth and elevation scanning without using phase shifters. Aim. To study and simulate a ring multi-beam antenna system with the ability to frequency scan, as well as the ability to form several beams simultaneously. To perform simulation when feeding different ports to assess the capabilities of forming different antenna beams, as well as in multi-beam mode. To study the possibility of beam deflection by frequency with the determination of the range of operating frequencies. Methods. The main results are obtained on the basis of electrodynamic modeling, which was performed using the finite element method in DS CST Studio Suite 2025. The main methods of analyzing the characteristics were based on the consideration of the radiation patterns, as well as their behavior during diffraction on echelette gratings. Results. The characteristics of the antenna system were obtained in the frequency range from 8,3 to 10 GHz. It was found that the antenna system allows implementing full-azimuth scanning by switching a different number of input ports. It is shown that the proposed design of the antenna system can be controlled both in the beam direction and in the main lobe width by switching a different number of antenna elements, while maintaining frequency scanning in a wide range of operating frequencies. It is found that the antenna allows for the formation of two differently directed beams with frequency scanning. Conclusion. The proposed antenna system can be used to implement high-frequency detection of small targets, implement a noise-immune communication channel with frequency tuning to keep an object in the antenna beam. The peculiarity of the proposed multi-beam antenna is the possibility of implementing two-coordinate scanning based on frequency scanning and switching connection of antenna elements.

The problem of estimation of the phase coordinates of the object whose motion is described by a system of differential equations is considered. For estimation, the Kalman filter equations following from the solution to the generalized Stratonovich equation in the Gaussian approximation are used. The generalized Stratonovich equation makes it possible to consider the cases when, as an observation signal, a multidimensional image of the observation object is applied; i.e., the scalar function of an arbitrary number of variables describing the specificity of the observation device. It is shown that the data array obtained from the used set of observation devices is included into the generalized Stratonovich equation and in the Kalman filter equations in the form of an additive combination of time derivatives of the likelihood functionals of each of the observation devices. Each of these functionals can consider the correlation of observation noises.

The article is devoted to the study of the organizational and economic mechanism for ensuring the sustainable competitiveness of an enterprise in the context of the digital transformation of the economy. The purpose of the research is to develop an organizational and economic mechanism to ensure the sustainable competitiveness of an enterprise in the context of digital transformations of the market environment. In the course of studying the issue of creating a mechanism, such approaches as analysis, systematization, and induction were used. The article analyzes various scientific papers that are devoted to a recently emerged concept related to ensuring stable competitiveness. As a result of the conducted research, it was revealed that the issue of sustainable competitiveness of the enterprise has not been thoroughly and in detail studied. This creates significant gaps in this field of science. The paper emphasizes the need to develop a mechanism that would facilitate the targeted and gentle improvement of an economic entity, allowing it to adapt painlessly and quickly transform to the current economic realities. The main results of the study include: 1) visualization of the mechanism functioning in the context of the model of ensuring sustainable competitiveness of the enterprise is presented. It is of key importance for the logical application of the structural links on which competitiveness depends in the context of the digital transformation of the economy; 2) it is established that the structure of the organizational and economic mechanism ensuring sustainable competitiveness of the enterprise must remain stable. At the same time, the methods of ensuring competitiveness may vary depending on the specific characteristics of the development of economic entities, which makes this toolkit adaptive in the face of constant transformations of the economic environment. The scientific and practical value of the research lies in the development of a set of tools and methods that have been integrated into a single system for effective strategic management of the company. This helps to reduce the negative impact of external factors on business in the context of digital transformation.

Objective: To quantitatively assess the hardness, elasticity, and plasticity, and to determine the influence of structure and substructure on these parameters in Li-Nb-O system films.Experimental: Li-Nb-O system films with a thickness of ~0.8 μm were grown on non-heated substrates (oxidized single-crystal silicon wafers (SiO₂ layer ~0.4 μm), single-crystal lithium niobate with (0001) orientation) by ion beam sputtering of a lithium niobate target. Thermal annealing of Li-Nb-O films on substrates was performed in air for 10 min (until complete crystallization) at temperatures of 550, 650, 700, 750, 800, and 850 °C. The heterostructures (film/substrate) were cooled with the furnace. The phase composition of the films was investigated by X-ray diffraction (XRD) and selected area electron diffraction (SAED). The substructure was studied by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM, Tecnai G2 30ST) of cross-sectional specimens prepared by ion milling using a Quanta 3D setup. The surface morphology was investigated by scanning electron microscopy (SEM, Teskan Mira) in the topologicalcontrast mode and atomic force microscopy (AFM, Solver47). Mechanical properties – hardness (H) and Young's modulus (E) – were determined from nanoindentation (NI, NanoHardness Tester CSM Instruments) measurements using a Berkovich diamond indenter under the following conditions: maximum load 10 mN, loading rate 10 mN/min, and unloading rate 15 mN/min. Results: It was found that thermal annealing in an oxygen-containing atmosphere at 750°C induces crystallization of quasi-amorphous Li-Nb-O films and the synthesis of single-phase LN films with lattice parameters closest to those of stoichiometric single-crystal LN. The most probable mechanisms of irreversible deformation in LN films are: brittle fracture, plastic deformation of crystallites, and grain boundary sliding. LN films synthesized at 650-750°C are most susceptible to brittle fracture. Brittle fracture occurs due to the buildup of macrostresses in the films, resulting from different coefficients of thermal expansion (CTE) of the film and the substrate. The fracture toughness of the films increases significantly when using a substrate with a CTE close to that of the film. The hardness of nano- and microcrystalline LN films is always higher than the hardness of quasi-amorphous Li-Nb-O system films. The decrease in the hardness of а films synthesized at high annealing temperatures is due to a decrease in the concentration of point defects and an increase in the size of the crystallites