The object of research was a fiber optic drone (multicopter) with a variable-length cable (VLCD) in a spatially inhomogeneous field of mass and surface forces. The aim of research was to develop in a spatially inhomogeneous field of mass and surface forces a nonlinear model for this system (VLCD model), for which the principle of hyperbolicity was satisfied. In this case, the model takes into account various internal (mechanical and physical characteristics) and external (control system, distributed loads, etc.) factors. The finite element method (FEM) is employed to build the VLCD digital model due to its efficiency in determining the force and geometric characteristics of the stress-strain state during the non-stationary processes in real time. The comparison of the efficiency and accuracy of solving the cable dynamics equations using the Euler and Crank-Nicolson difference schemes shows that the numerical algorithm based on the Crank-Nicolson difference scheme provides the necessary accuracy and is more effective for the numerical modeling of transient processes in distributed systems. The qualitative efficacy of the author’s results is based on the sound construction of the VLCD model, the proof of the Cauchy theorem according to Courant’s interpretation for the hyperbolic component of the model. The quantitative validity of the nonlinear VLCD model in a spatially inhomogeneous field of mass and surface forces is demonstrated through the development of stable numerical algorithms, and feasibility of their practical application. The parameters of the model parabolic component are determined for optimal computation of a variable-length cable. The accurate VLCD model and stable finite discrete model (FDM)-based numerical algorithms for its computation are developed.
The object of this research is the thermodynamic evaluation of the free energy between deoxidizers in molten steel smelted in an induction furnace. The problem of estimating and using data on the free energy of interaction between solutes with a high affinity for one another, such as oxygen, a strong deoxidizer in liquid iron, is addressed. Particular attention is paid to the relationship between the interaction parameters and the equilibrium constant. The findings are confirmed by evaluating data for the equilibrium conditions of the Ca-O and Al-O systems in liquid iron. It has been established that when deoxidizers – Al, Si, Mn, Ti, Ca, etc. – are introduced into a liquid metal (e.g., liquid steel), they interact not only with oxygen but also with each other through the metal as a carrier solution. A key feature of this research is the establishment of a rational Ca content in the liquid metal for the formation of liquid Ca-Al2O3 compounds (or a solid compound). In this case, the equilibrium oxygen content can be further reduced by reducing the oxide activity. Moreover, Ca is also used to combat nozzle fouling in the pouring ladle or tundish, which occurs when pouring steel deoxidized by Al. It has been established for the first time that a small amount of Ca in steel increases the solubility of oxygen relative to Al, which in turn makes the steel insensitive to small temperature drops or secondary oxidation in the ladle. The application area is to evaluate the free energy of interaction between various deoxidizers in liquid steel to obtain real-world data on the equilibrium constants of various systems. This data enables the development of high-quality steelmaking technology tailored to production requirements. The key features of this research include the combined use of the z-coordinate transformation, correlation analysis and polynomial regression to determine the concentration range in which first-order interaction parameters remain valid for Fe-Ca-O and Fe-Al-O equilibria.
This research evaluates the behavior, efficiency, and suitability of two electric-vehicle transmission configurations using a permanent-magnet synchronous motor (PMSM): a continuously variable transmission (CVT) and a conventional gear transmission. A three-phase PMSM model with regenerative braking capability is developed in MATLAB/Simulink to generate realistic torque, speed, and power signals. These signals are applied to two finite-element transmission models created in Ansys from 3D laser-scanned geometry of a production powertrain. The simulations examine how transmission architecture affects power delivery, loss distribution, regenerative-braking efficiency, and durability under representative driving conditions.The numerical results quantify differences in load paths, friction losses, thermal behavior, stress concentrations, and wear progression. The CVT configuration provides smoother torque transfer, wider high-efficiency operating regions, and higher braking-energy recovery because its continuously adjustable ratio keeps the PMSM near favorable torque-speed points. The conventional gear transmission shows higher structural rigidity, lower sensitivity to thermal rise, and more predictable stress distributions due to its fixed-ratio layout.These findings indicate that CVT integration is advantageous for variable-speed urban driving cycles and efficiency-oriented electric vehicle (EV) designs, whereas conventional gear transmissions remain suitable for high-load, temperature-constrained, or long-duration operating conditions. The research offers guidance for EV powertrain selection, early-stage drivetrain design, regenerative-braking strategy development, and durability assessment across diverse operating scenarios.The simulation results show specific values for stress and efficiency. The maximum stress on the CVT belt is about 237.4 MPa. The CVT also transfers torque more smoothly, keeping torque variation under 1.0 Nm during speed changes. In contrast, the chain-coupled gear transmission has torque variations of more than 3.5 Nm. Therefore, the CVT helps the motor run more efficiently by keeping it in optimal operating zones.
The aim of the work is to estimate the barometric effects for the neutron component of cosmic rays at the Tashkent and Alma-Ata stations during periods of maximum solar activity. The article analyzes the detailed instrumental characteristics of the Tashkent and Alma-Ata stations, the detector design, the data collection and processing system, and the main scientific results obtained during continuous observations. As a result, the average annual barometric coefficients for the neutron component were determined: for the Tashkent 0.686 ± 0.016%/mb, and for the Alma-Ata 0.668 ± 0.016%/mb. The humidity effect was also estimated for the Moscow station. It was found that the regression models describe the observed variations with high accuracy (Р2 ≈ 0.97), which confirms their reliability. The results obtained show that they can increase the accuracy of neutron monitor data correction, improve the efficiency of detecting primary cosmic ray variations, and record space weather events. The proposed approach is shown to be effective in long-term monitoring of cosmic rays and studying the Sun-Earth relationship. The coupling coefficient, which expresses the contribution of cosmic ray variations, was found to be 1.126 ± 0.014 for the Alma-Ata and 1.096 ± 0.014 for the Tashkent. These values indicate that the intensity changes recorded by neutron monitors are in high agreement with cosmic ray variations. The results obtained show that atmospheric pressure is the main meteorological factor affecting the counting rate of neutron monitors. The corrections significantly improved the accuracy of the data, making it possible to distinguish heliophysical phenomena such as Forbush depressions, 27-day variations, and long-term modulation of galactic cosmic rays.
The aim of this research is to perform a multi-objective optimization of the Ti6Al4V alloy grinding process using Minimum Quantity Lubrication (MQL). An experimental process was designed according to the Taguchi method, in each of which the values of four input parameters were varied, including lubricant pressure, workpiece velocity, feed rate, and depth of cut. Seven parameters, also known as 7 criteria, were measured in each experiment, including surface roughness, three cutting force components, and three vibration components of the grinding system. Four method were used to calculate the weights for the criteria, after which the DEPART method was applied to solve the multi objective optimization problem. Regardless of which method was used to calculate the weights of the criteria, a single unique optimal solution for the input parameters was always identified. This is explained by the fact that the application of the DEPART method to solve the multi objective optimization problem is based on pairwise evaluation using deviations, so the optimal solution found does not depend heavily on the weights of the criteria. Accordingly, the optimal value of the oil pressure is 4 atm, the workpiece velocity is 10 m/min, the feed rate is 13 mm/stroke, and the depth of cut is 0.02 mm. When machining with this optimal set of input parameters, all seven output parameters achieve small values. The application of the optimal values of the technological parameters found in this research, in addition to ensuring that the machined surface has low surface roughness, also ensures other requirements regarding dimensions, geometric shape, or the tool life of the wheel as well as the machining system because the cutting force and vibration components all have small values.
