The paper considers a geometric scheme, a mathematical model and an algorithm for shaping a non-linear rotation surface. It is known that in Euclidean geometry and mechanics the transformation of rotation is linear, while distance and angle are its invariants. The authors proposed a geometric scheme of non-linear rotation, in which the axis of rotation is a smooth spatial curve and the object of rotation is a smooth line. Several propositions, a lemma and a theorem are proved, which allow one to form the initial data in the problem of nonlinear rotation, the solution of which is the parametric equations of smooth surfaces. The research results make it possible to expand the variety of cyclic surfaces in the existing classification of analytic surfaces. They can also be useful in the creation of CAD, which provides for the design of surface forms of products for mechanical engineering, construction, architecture and other practical areas based on cyclic surfaces.

The article presents a modified algorithm for automated formation of geometric model of ship hull surface. The use of developed algorithm for construction of NURBS-surfaces allows to decrease labor input in several times in comparison with the use of manual labor when modeling surfaces in standard shipbuilding modeling systems like Sea Solution, Rhino and others. On the basis of this algorithm a software application is created, implemented in HTML5, JavaScript. The application allows to solve problems of creating and displaying three-dimensional models of ship surfaces in a standard the Internet browser. The program allows you to quickly analyze variants of the geometry of the ship hull model by adjusting the initial data, which significantly increases the productivity of the designer. It is possible to export the formed NURBS-surface for use in other design systems, including ship hull construction modeling, stability calculations, hull shell cutting and other tasks.

When performing work on the repair of the pipeline, the main machine designed for digging trench pits is a single-bucket excavator. Pit digging currently uses two excavators moving along the pipeline in parallel directions. In order to increase the efficiency of digging pits, it is necessary to check whether it is possible to dig pits with only one excavator located in the middle of the pipeline, as well as to dump soil into a dump located on both sides of the excavator's line of motion. Cases are considered when pit digging is performed by a non-modernized single-bucket excavator, an excavator with the ability to rotate the boom section and an excavator with the ability to rotate the bucket. The full cycle of the process of digging a pit with dumping of soil into a dump is also considered. On the basis of the research carried out, an algorithm for automated control of the movement of the excavator bucket when digging trench pits is developed. The results of computer simulation of the movement of the excavator manipulator when digging trench pits are presented.

In the article the authors raised the problem of reduction of geometry-graphic training departments in Russian universities, which for the last 16 years amounted to about 1/3. The reasons for this situation are considered, among which should be emphasized the lack of highly qualified personnel of higher qualification, capable of leading scientific schools in the profile of geometric-graphic training departments. It is proposed to activate the work of the departments of geometry-graphic training on training of scientific-pedagogical staff of higher qualification in postgraduate and doctoral studies. It is also proposed to fix for engineering specialties at the level of the state standard the necessary labor intensity and more stringent requirements to the staff conditions for the implementation of the basic professional educational program with regard to the disciplines of geometric-graphic training of students.

Cylindrical gears with arched teeth have the required performance in conditions of both non-rigid machine bodies and inevitable manufacturing and assembly errors. Error compensation is carried out by self-alignment of the wheels, the possibilities of which are limited in gears with one line of engagement. The article investigates an adaptive gear with arched teeth with two contact zones, which provides self-alignment of the wheels, regardless of the angle of misalignment of the teeth in engagement. The most promising in terms of implementation in the industry method of cutting arched teeth with a circular cutter head by the rolling method with a single division on CNC machines. Solved and illustrated by examples of the problem of calculating the parameters of the process of shaping the surfaces of arched teeth, which ensure the passage of two active lines in the meshing of the teeth through the given centers of the contact patches and the law of change of the transfer function required for the implementation of the approximate nature of the meshing.

Metalworking is the main industrial production and its technological process requires dust cleaning. The choice of dust-collecting units from a trivial approach turns into a compact-multi-criteria one and requires the study of methods for its implementation. This article uses the method of selection of dust-cleaning equipment of cyclone type based on dust from metalworking industries based on the Hierarchy Analysis Method.

This article discusses one of the ways to increase the economic efficiency of the Gazprom Transgaz Kazan Limited Liability Company (Gazprom Transgaz Kazan LLC) in the operation of gas heaters at a gas distribution station by replacing the gas heating unit. The advantages of the equipment «ISTOK-60» over PTPG-30 are described, the calculation of the economic effect from the introduction of new equipment is given. The object of the study is the process of operating gas heaters at the gas distribution station of OOO Gazprom Transgaz Kazan, the subject is a method for increasing the economic efficiency of gas heaters.

As a result of the study, the expediency of replacing old equipment with new one is proved and the economic effect is calculated. The article also raises questions about the possibility of using the concept of «Lean production» in the process of gas distribution. One of the methods of lean manufacturing — SMED is proposed as the main one.

An energy-efficient switched reluctance electric drive is considered in relation to electric rolling stock. It fully meets such requirements as good adjustment properties, high energy efficiency and operational reliability. The scientific and technical value of the results of the work lies in the development of an algorithm for controlling a traction switched reluctance motor that reduces the operating current while providing the necessary power. The calculations are made by means of specialized programs interacting with each other FEMM and MATLAB. The materials of this study are of practical value for improving the operational and technical and economic indicators of electric rolling stock.

The main purpose of this work is to create conditions for the use of switched reluctance motor in the traction electric drive system of rolling stock by increasing the reliability of its bearings. The object of the study is the traction switched reluctance motor. The task has been set, which consists in developing an algorithm that allows to calculate the characteristics of the traction switched reluctance motor at the stages of design and production, taking into account the forces of a one-way magnetic attraction. The forces of one-way magnetic attraction, arising in the air gap of the electric motor with two types of its non-uniformity are studied. A proposal has been made to limit the force of the one-way magnetic attraction to a force at a permissible residual imbalance. As a result, an algorithm for determining the characteristics of the traction switched reluctance motor is unique in its kind, which makes it possible to reduce the effect of forces of the one-way magnetic attraction on bearings. The use of switched reluctance motor with a long service life of bearings in the traction drive system will make it possible to obtain a new competitive rolling stock.

An assessment is made of the influence of the parameters of a controlled part by the magnetic method of non-destructive testing on the gradient of the magnetic field strength of the measuring transducer. A simplified design of a pulsed gradiometric transducer is presented, and its parameters for conducting experiments are indicated. A mathematical model for calculating the output signal of a gradiometer fluxgate used to obtain output data is considered. The dependences of the magnetic field intensity gradient on the distance between the sensor and the plane of the controlled part, on the coercive force and thickness of the hardened layer, as well as on the thickness of the controlled part are studied. Conclusions are drawn based of the experiment performed.

Formulas for calculating continuous admissible currents and active power losses for overhead power transmission lines under conditions of natural and forced convection for insulated and non-insulated conductors are presented. The correct determination of maximum current loads plays an important role in the efficient use of the load capacity of power transmission lines, and the refinement of the calculation of active power losses is the basis for increasing the efficiency of energy transmission. The results obtained can be used in the selection of measures aimed at increasing the capacity of overhead lines and reducing energy losses.

The article considers the temperature distribution with increased currents in the non-stationary thermal regime of overhead power lines. The temperature distribution along the length of the line for wires of AC-240/32 and G(Z)TACSR 240 grades is constructed. Temperature dependences on time are plotted. The practical value of the mathematical model considered in the article lies in determining the maximum temperatures of overhead lines of different sections in normal or post-emergency wire mode. A comparative analysis of active power losses in a stationary thermal regime is carried out with and without taking into account axial heat transfer. The comparison showed that taking into account the axial heat transfer refines the active power losses, which allows introducing measures to reduce these losses with greater accuracy.

This paper presents a method for determining the outgoing line with a single-phase fault for 6–35 kV networks with a non-sinusoidal loads. The paper considers the relevance of applying the mathematical apparatus of the wavelet transform together with the traditional methods of fault location. The application of the wavelet is relevant in the problems of decomposition of non-sinusoidal current signal of outgoing lines. This is due to the loads of modern enterprises of the oil producing sector of Khanty-Mansiysk Autonomous Okrug–Yugra. It is proposed to modernize the existing algorithm for relative measurement of the level of higher harmonics. The proposed method makes it possible to determine the outgoing line by the total energy of the spectrum of higher harmonics for different network configurations.

This paper presents a method for determining the optimal structure of an isolated electrical network, taking into account the geographical features of the area in which it is located. A distinctive feature of the method is the removal of restrictions on the number of equivalent routes of power transmission lines sought, with subsequent filtering of the routes, taking into account technological and technical limitations. Thus, the obtained method can be used to organize microgrids in areas remote from the Unified National (All-Russian) Energy Grid with distributed generation and load.

The article is devoted to the problem of identification of leakiness of pipeline fittings. A measuring system for leak monitoring is described. In contrast to the organoleptic approach adopted in practice, automatic signal processing is proposed, followed by a conclusion about the tightness of the valve. The automatic processing is based on an algorithm based on the analysis of the singular spectrum, which provides an increase in sensitivity. The effectiveness of the complex is confirmed by the test results of the measuring complex using a hydraulic stand.

The effect of preliminary heat treatment on the morphology of carbon layer formed on the surface of chlorinated polyvinyl chloride with the addition of ferrocene (10 % of polymer weight) under the impact of a high-power nanosecond-durable ion beam has been studied. Preliminary exposure of samples in an oven at different temperatures for 1 hour leads to partial dehydrochlorination of the surface layer of the polymer film and interchain crosslinking, creating centers for the start of the carbonization reaction, and thus affects the formation of carbon nanostructures during subsequent irradiation with a high-power ion beam. The possible mechanism of carbon nanostructures formation from chlorinated polyvinyl chloride under the impact of a high-power ion beam and the mechanism of the influence of preliminary heat treatment on it are considered. It has been established that different heat treatment temperatures lead to different morphologies of the resulting carbon nanostructures. On the control sample and the sample subjected to heating to 100 °C, only nanofibers are formed, preheating to 150 °C leads to the formation of a porous structure with nanosized pores under the nanofibers, and preheating to 200 °C leads to a significant decrease in the porosity and concentration of nanofibers.

The article proposes an all-embracing approach to designing a temperature compensated crystal oscillator in Keysight ADS CAD system, which allows: to investigate the conditions for the occurrence of self-oscillations in a given oscillator circuit; analyze the temperature-frequency characteristics of the resonator; form requirements for the frequency control function; simulate noise characteristics of the generator; optimize the circuit according to the given parameters. In contrast to the well-known numerical design of a thermally compensated crystal oscillator in SPICE programs with subsequent analysis of the results in a mathematical program, for example, Mathcad, the proposed method allows us to investigate the real shape of oscillations, the spectral purity of the output signal, take into account the nonlinear influence of the circuit and more subtle effects.

In this paper, the applied problems of designing a bridge resonant converter with a high-voltage arc ignition system in the channel of an electric arc motor is solved. The development of a bridge resonant power supply is presented, a review and analysis of power sources of arcjet thruster of various capacities is carried out.

The theoretical aspects of calculating the main parameters of the source are considered. The transfer function describing the gain of the resonant circuit of the power supply is given. With the help of the transfer function, gain diagrams are constructed for various values of the Q-factor of the contour. A prototype of a power supply, a starting system and an arcjet thruster is presented. A series of experiments aimed at identifying the operability of the source is carried out. According to the experimental results, the maximum output power of the source wiz 182,4 watts, and the maximum efficiency is 87,5 %. Frequency spectra of the output current of the power supply are obtained. The current-voltage characteristics for the Ar and N2 are constructed.

In the course of the study, phenomena related to the chaotic dynamics of the arc in the engine channel are discovered. Chaotic fluctuations are observed at the moment of starting the engine and disappeared after steady-state operation.

The paper proposes the developed technique for automated synthesis of integrated microwave LC filter layouts with passband losses minimization by minimizing interconnection lengths and searching for optimal layouts of conductors, inductors, and capacitors. Algorithms for minimizing losses and length of LC-filter interconnections are proposed. The layouts of conductors, inductors, and capacitors are optimized based on silicon-verified models that take into account the main characteristics and limitations of the process, skin effect, edge effects, substrate and via influences. The CAD is developed in MathCAD software based on the proposed technique. The use of CAD made it possible to reduce the engineering time for integrated LC-filters to tens of minutes, reduce the filters passband losses by 1,1–2,7 dB and increase the AFCs gain slope by 47–267 dB/dec.

The paper presents the results of laboratory experiments to study the parameters of the gas environment during the combustion of wood, rubber and plastic under conditions that exclude oxygen access to the reaction area. A laboratory bench has been developed to create the conditions. Graphs of temperature changes and reduction of light transmission of combustion products accumulated in the upper part of the combustion chamber layer have been obtained. Changes of the controlled parameters are analysed and correlation dependences between them are obtained. The results obtained can be used as estimates for building prediction models of fire development in enclosed storage rooms, as well as for assessing the fire hazard of substances when burning in an enclosed volume.