A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

The process of heat exchange in the rod, taking into account the correction for heat loss through its side surface

The article is devoted to the issues of stationary heat transfer. The subject of the study is the process of thermal conductivity in the rod. The article deals with heat transfer through a rod with a small cross-section. The rod is supposed to be so thin that the temperature at all points of its cross-section can be considered the same. The method of power series expansion is used. Expressions are obtained for finding the temperature field, taking into account the correction for heat loss through the lateral surface of the rod. Formulas are also derived to determine the coefficients of external heat transfer and the coefficient of thermal conductivity based on known values of temperatures and heat flows, which will allow us to evaluate the necessary modes and results of processing large-sized parts.
Keywords: heat transfer; rod; heat loss; heat flow; thermal conductivity; temperature field; heat exchange.

I. N. Ganiev, Kh. O. Odinazoda, F. K. Khojaev, Kh. M. Khojanazarov (Tajik Technical University named after Academician M. S. Osimi, Dushanbe, Republic of Tajikistan)

Heat capacity and thermodynamic properties of lead babbit BC (PbSb15Sn10К) modified with potassium in the range of 300…550 K

The article presents the results of a study of the temperature dependence of the specific heat and changes in the thermodynamic functions of lead babbit BK (PbSb15Sn10K), modified with potassium in the «cooling» mode in the range of 300–550 K. Based on the experimental dependences Cp = f(T), changes in enthalpy, entropy and Gibbs energy of this lead babbit.
Keywords: lead babbit BK (PbSb15Sn10K); potassium; «cooling» mode; heat capacity; enthalpy; entropy; Gibbs energy; temperature dependence.

K. V. Klochkova (MSUT «Stankin», Moscow); A. O. Kucherova (State Research and Design Institute of the Rare Metal Industry (JSC «Giredmet»); MSUT «Stankin», Moscow)

Development of a database of aluminum alloys of the 7XXX series

Aluminum alloys are widely used in various industrial fields due to their unique properties. The development of a database of 7000 series aluminum alloy properties is critical for materials scientists, researchers and engineers to more conveniently and quickly select the right material. The database was created by compiling data from various sources. The data was organized and analyzed using statistical methods to identify trends and patterns in the properties of 7000 series aluminum alloys.
Keywords: database; aluminum alloys; mechanical properties; database structure; 7000 series alloys.

L. A. Simonova (Kazan Federal University – Naberezhnye Chelny Institute, Naberezhnye Chelny); K. V. Klochkova (MSUT «Stankin», Moscow); A. O. Kucherova (State Research and Design Institute of the Rare Metal Industry (JSC «Giredmet»); MSUT «Stankin», Moscow)

Formation of the knowledge base of the decision support system for modeling mechanical properties on the example of aluminum alloys of the 7ХХХ series

Aluminum alloys are widely used in industries ranging from aerospace to electronics due to their unique properties such as strength, durability and corrosion resistance. The development of new alloys with improved or adapted properties is an important task for materials scientists and engineers. For a more efficient implementation of the process of obtaining new alloys by saving time, resources and budget, it is necessary to create an intelligent decision support system that would allow predicting their properties. The main component of such a system is the knowledge base, the formation of which is the goal of this work.
Keywords: aluminum alloys 7000 series; rule base; precedents; decision tree; expert system; alloy prediction; classification.

A. N. Bludov (Branch of the National Research Technological University «MISIS» in Gubkin, Gubkin)

Restoration of the profile of the tread surface of wheel sets of opencast railway transport by a method that does not require rolling out

This article describes methods for restoring the rolling profile of wheel sets on a quarry railway transport without rolling them out of the rolling stock. The various types of machines used on mining railways are described, such as wheel milling machines, wheel lathes with manual profile adjustment and machines with a copying system. The article presents the technical characteristics of each of the machines, as well as their advantages and disadvantages, including the schemes used for basing and copying the wheel profile. The issues of accuracy and productivity of processing are considered, as well as the main directions for improving methods for restoring the profile of the rolling surface of wheelsets without rolling them out of the rolling stock are identified. It also contains recommendations for improving the productivity and economy of the process. This article may be useful to specialists in the field of railway transport who are interested in choosing the best methods for restoring the profile of wheel sets in open-pit railway transport.
Keywords: wheelset; tread profile; processing accuracy; restoration methods; milling; turning; grinding; copying; productivity; basing pattern; reference profile.

N. A. Anikin (N. D. Zelinskii Institute of Organic Chemistry, Moscow)

A complex of methods for drastically accelerating DFT calculations of giant biomolecules: reducing the Coulomb contribution to fast two-center integrals and extracting the multipole contribution – the path from O(N4) to linear scaling

Quantum-chemical calculations of the electronic structure of actual giant bioactive molecules, including calculations of thousands of protein-ligand docking complexes of thousands of atoms by the common DFT method, are extremely resource-intensive, often even when using a supercomputer. In this paper, after a brief immersion in the current state of quantum chemical calculations of large and very large molecules, we consider the possibility of accelerating one of the limiting stages of such calculations - the calculation of two-electron four-center Coulomb integrals of atomic orbitals (AO). A consistent set of measures-methods is proposed to reduce these integrals first to three-center, then to two-center integrals of specially selected auxiliary density functions. The latter have a long-range multipole contribution, which for very large molecules is efficiently accelerated by the FMM fast multipole method. The short-range exponentially decaying residual is quickly calculated by pre-fitted splines from center-to-center distances. For efficient selection of spline parameters for manifold AOs and their two-center products, it is proposed to first approximate them by linear combinations of fixed Gaussian functions with exponents forming a geometric progression. All this makes it possible to move from the growth of O(N4) resources to linear scaling of computer resources, which is very economical for very large molecules.
Keywords: high-speed quantum chemical methods; large molecules; DFT; Coulomb integrals; docking complexes.

A. N. Petrov, M. A. Petrov (Moscow Polytechnic University, Moscow); S. V. Mizera (JSC «Colloidal-graphite production», Voskresensk); S. A. Kharitonov (MDB «Gorizont», Dzerzhinskiy)

Investigation into lubricant materials for rivet cold heading with cold heading automatic machine

This article deals with researching lubricants for rivet cold heading made of Ni-based alloys. Physical and mechanical properties of foreign and domestic lubricants were investigated. Besides, technological properties the analyze of applicability was carried out as well. Production test was carried with cold heading automatic machine of brand name CHUN ZU (model CH-3). The comparative results of the tests were presented. The results have shown that domestic lubricant can be applied during rivet cold heading operation. Lubricant ONV 120 was recommended for it instead of the foreign one ZET CUT 165.
Keywords: lubricant; cold bulk forming; heading; rivet; Ni-based alloys; lubricants’ properties; cold heading automatic machine; import replacement.