Analytical Modeling of a Heat Source under Welding of a Steel Sleeve by the Centrifugal Method Using an Axisymmetric Electric Arc

S.P. Glushko

An analytical solution for calculating the heat concentration coefficient under bimetallization is presented. Modeling of the heat source shows the advantages of the exponential function for calculating the heat flux density. The study improves temperature control at the interface of materials during the surfacing of sleeves. The results obtained contribute to increasing the accuracy of temperature fields and the quality of bimetallic compositions. New methods provide reducing dependence on experimental data in the bimetallization process.

Study of Operating Modes of a Biofuel Diesel Engine

V.A. Likhanov, О.P. Lopatin

The paper examines the power and economic indicators of a diesel engine. It is shown that operation on ethanol and rapeseed oil changes combustion parameters. An increase in the ignition delay period affects the stability of the process. The use of pilot (rapeseed) oil is proposed to solve the identified problems. The results confirm the possibility of replacing petroleum fuel with alternative energy sources.

Analysis of Temperature Characteristics of the Discharge Formed by a Jet Electrolytic Cathode and a Metal Anode

A.I. Popov, V.I. Novikov, D.N. Ivanov, I.A. Kozyrskiy

Temperature characteristics are studied during electrolytic jet machining. A heat balance equation is developed to describe heat distribution in the system. Significant temperature variations depending on electrolyte flow rate and voltage are found. The results can be used to optimize electrolytic plasma machining technology in various industries.

A Method for Monitoring the Reliability of Technical Systems by Identifying the Entropy of the Causes of their Failures

S.V. Teplyakova, A.T. Rybak, A.V. Olshevskaya, A.S. Prutskov

The article presents a new method for monitoring the reliability of technical systems. The study identifies entropy as a key factor in assessing the causes of machine failures. The results of the analysis confirm that the behavior of machines can be determined by calculation. The effect of design features on the probability of failure-free operation is determined. The method offers quantitative and qualitative relationships between the design and failures of parts.

Forecasting Delivery Time of Goods in Supply Chains Using Machine Learning Methods

V.K. Rezvanov, O.M. Romakina, E.V. Zaytseva

An investigation of the application of machine learning algorithms for predicting delivery times in logistics is presented in the paper. The decision tree method provides high accuracy of predictions with a determination coefficient of 0.986. It turns out to be the least resource-intensive. The application of the proposed algorithm will allow small and medium enterprises to optimize their logistics operations with minimal computational resources. The obtained results open up new opportunities for improving supply chain management using simple machine learning models.

Ab initio Calculations of the Electronic-Energy Structure and Optical Properties of Lanthanum and Neodymium Pyrozirconates

A.A. Lavrentyev, B.V. Gabrelian, Vu Van Tuan, K.F. Kalmykova

Model calculations of the electronic structure of the compounds La2Zr2O7 and Nd2Zr2O7 are performed in the study. The densities of electronic states are obtained, and the optical characteristics of the compounds are calculated. High absorption coefficients are found in a wide energy range. The results allow us to explain the features of the experimental X-ray spectra. The study opens up new prospects in materials science and optics.

Integration of Sensor Data and Mathematical Modeling of Underwater Robot Behavior Using a Digital Twin

M.D. Gladyshev, A.V. Rybakov

A method for predicting the dynamics of an underwater robotic complex is developed. A digital twin system that integrates sensor data and mathematical modeling is presented. Experiments are conducted that confirm the high accuracy and stability of the model under uncertainty. Visualization in Unity improves interaction with the system and allows for comparative analysis. The results show the potential of using digital twins for autonomous systems in complex environments.

Approximate Synthesis of Controllers in Nonlinear Dynamic Systems over a Semi-Infinite Time Period

A.V. Panteleev, A.A. Yakovleva

New sufficient conditions for the existence of  control for continuous nonlinear systems that are linear in control and disturbance are determined. The proposed method is based on the minimax approach and the extension principle.  An algorithm is developed that simplifies the procedure for synthesizing  controllers based on an approximate replacement of a nonlinear system with a simpler system similar in structure to a linear one. The results of the study open up new possibilities for solving various control problems, e.g., problems of stabilizing aircraft of different classes in the presence of external actions.