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In recent decade considerable interest has been given to development and study of oil free vacuum pumps. Design of new scroll vacuum pumps is possible only on the basis of reliable mathematical model. In this work verification and validation of mathematical model based on modelling by control volume approach is carried out for a scroll vacuum pump with one-sided one-wrap involute scroll, as an example. The analysis was carried out by comparison of indicator diagrams obtained at different pressures, rotating speeds and driveshaft eccentricities. It is showed that data obtained with the help of mathematical modelling give good agreement with CFD modelling results and with experimental data. The difference is within experimental error. [ABSTRACT FROM AUTHOR]

The article is dedicated to the computerized evaluation of publication effectiveness using accessible API of citation bases. The review of scientific sources indicates that the use of API of such well-known companies and agencies as Elsevier, Clarivate Analytics, Crossref as applicable to international, including domestic, citation indexes plays an important role when creating such systems. The main aim is the analysis of publication activity not only of an organization but also of its divisions. The results of such analysis allow developing effective directions of a higher educational institution policy to motivate for research, creating the necessary reports in the formalized form in the time mode, approximated to the real one, upon the requests. The global analytical citation systems, such as Scopus, Web of Science and Russian Science Citation Index, have such a disadvantage that they often contain the distorted information about the authors' affiliation for the reasons beyond their control. This feature is conditioned by the lack of connection between the databases of publications and the actual place of work of the authors. The solution of such a problem depends on the integration degree of the data obtained for publications into the information network of the higher educational institution. As a particular case, the example of the program module aggregating metadata of articles from three bases, including the use of Elsevier API and allowing the calculation of the actual complex score of the publication effectiveness was developed. The research demonstrated that the actual value of this score significantly differs from the desired one, which is calculated based on the data of the domestic scientific citation index. [ABSTRACT FROM AUTHOR]

The paper considers the main integral and dynamic characteristics of a rotor system on hydrodynamic journal bearings lubricated with a magnetorheological fluid. A new design has been proposed in the field of active journal bearings for lubrication by magnetorheological fluids, namely, a journal bearing with full coverage of the gap area by a magnetic field. The basic mathematical relationships, initial and boundary conditions used for calculation of the bearing characteristics are given. Distributions of the friction coefficient, relative eccentricity, stiffness and damping parameters are given. The trajectories of movement of the center of the rotor in various operating modes are presented. Conclusions about the applicability of magnetorheological lubricants for controlling the dynamic characteristics of a rotor on journal bearings lubricated with magnetorheological fluids are presented. [ABSTRACT FROM AUTHOR]

Mathematical model of working process of scroll vacuum pumps was developed earlier to improve scroll vacuum pumps. For its verification experimental database for the object under study was required. For this purpose experimental unit to test oil free scroll vacuum pump is developed. Relationships such as pressure in pump working chambers vs rotation angle of the drive shaft, pump ultimate pressure vs drive shaft rotation speed, pumping speed vs pump inlet pressure, power consumption vs pump inlet pressure, temperature of the housing, orbiting and fixed scroll elements, gas at the inlet and outlet of the pump vs pump inlet pressure are obtained. Behavior of these parameters depending on pump working regimes is discussed. Experimental data will be used for verification of mathematical model of scroll vacuum pump. [ABSTRACT FROM AUTHOR]

The issues of ensuring the accuracy of the filaments’ production for additive manufacturing using the electron beam energy at the stage of drawing of a workpiece made of 12H18N9T steel were considered. The reduction ratio varied in the range from ε = 5 % to ε = 67.5 %. Calculations showed that the dimensions of a workpiece for producing filaments with a diameter of Ø 1.3-0.09 mm was limited by Ø 4.27-0.17 mm. It was experimentally established that the diameter of a filament made of 12H18N9T steel after the last reducing step (1.3 mm) exceeded the allowable diameter (1.3−0,09 mm) and equaled to 1.37 mm. This deviation is probably induced by elasto-plastic strains occurring in the wire in the drawing process. To provide the required accuracy of the filaments with a diameter of Ø 1.3-0.09 obtained by drawing of 12H18N9T steel, it was recommended to grin the diameter of a die taking into account the magnitude of the elastic deformations, i.e. provide the diameter 0.05 mm smaller than required. [ABSTRACT FROM AUTHOR]

The technological parameters of drawing for creating Ti-6Al-4V titanium alloy filaments were optimized. Selection of a lubricant for the manufacture of metal filaments of Ti-6Al-4V alloy (wire, rod) was carried out based on the evaluation of the tribotechnical properties. It was found that the most preferred type of lubricant is beeswax according to GOST 21179-2000. With sliding friction according to the “disc-pad” scheme, the friction coefficient with the speed of 150 rpm and the load of 300 N is 0.06. Since the drawing stress and force parameters do not depend on the drawing speed the drawing to obtain laboratory experimental samples of cylindrical filaments of Ti-6Al-4V alloy can be carried out at various speeds in the range from 30 to 360 mm/min. The drawing route of cylindrical filaments of Ti-6Al-4V alloy with dimensions from Ø4 mm to Ø1.2 mm was compiled based on the analysis of the dependences of drawing force, drawing stress and safety factor, as well as the mechanical properties of the manufactured products. [ABSTRACT FROM AUTHOR]

Due to the limited reserves of natural hydrocarbons, more and more attention has been paid to the problem of saving energy resources. Reducing energy consumption improves the environmental situation by decreasing harmful emissions to the atmosphere. In our country, despite the presence of significant reserves of oil, gas and coal, the costs of their production and transportation are constantly growing. Nevertheless, insufficient attention is paid to solving the problems of energy-saving control of MIMO energy-consuming industrial and domestic facilities, although theoretical studies have shown that optimal control can reduce energy costs or fuel consumption by 15–20% or more compared to traditional systems. Such facilities include multi-zone electric furnaces, multi-section drying installations, boiler installations, multi-drive machines and other installations operating on hydrocarbon fuels or electricity. Such facilities are used in housing and communal services, industrial enterprises and in everyday life. The development of a methodology for building intelligent systems of energy-saving control of MIMO process systems on a set of operating states is a fundamental problem for the industry. The solution of this problem is connected with the development of methods for solving a whole complex of diverse and complex problems, including those associated with the creation of models, methods and algorithms that minimize the cost of energy resources in the operation of MIMO systems taking into account possible changes in the state of functioning in actual operation. The paper considers the synthesis of algorithms for energy-efficient control actions for intelligent control of MIMO technological systems. The problems of synthesis and algorithmic support for their solution are explored using the example of a five-section electric convection heater RO400FC-C. The proposed algorithms are used for different operation conditions-heating, temperature maintenance, and an emergency mode associated with failures of individual heating elements during operation of the heater. [ABSTRACT FROM AUTHOR]

Procedure of conductance calculation of radial channels formed by moving walls in non-contact pumps and compressors in viscous gas flow regime is developed. Comparison of calculated data and data obtained by numerical solution of gas flow is carried out for inlet pressures from 100 to 105 Pa and wall velocities 5–40 m/s. Formula for approximate conductance calculation of channels with moving walls used as the initial approximation in the presented procedure is obtained for faster calculation. [ABSTRACT FROM AUTHOR]

Using the general theory of composite beams, we derived expressions for shear forces between cable elements. This study is the first to determine the forces of interaction between the armor and conductor of the submersible pump cable, which is considered as a composite beam with transverse bracing. The paper analyzes the forces of interaction of cable components and identifies the distribution pattern of the forces in the cable deformation zone. The findings can be used for designing submersible pump cables in the oil industry, taking into account high hydrostatic pressure and high temperatures. [ABSTRACT FROM AUTHOR]

A new thermographic nondestructive testing technique employing local spot heating pulse is proposed and described. In a homogeneous and defect-free sample heating forms a radially symmetric thermal wave registered by a thermovision camera. An image data processing algorithm allowing the thermal conduction and temperature diffusivity of materials to be determined with an accuracy of about 2-3% has been developed and tested. Sample defects and inhomogeneities distort the circular shape of isotherms on the surface of the test object. The amplitude and shape of such distortions can serve as defect tracers. The proposed non-stationary thermal field data processing algorithm can be used to determine the location and geometry of defects on both the visible and hidden surfaces of the examined shell. [ABSTRACT FROM AUTHOR]

The study demonstrates the key possibility to produce new nanofiber ceramic materials on the base of zirconium dioxide. A method for forming toroidal arrays of ceramic fibers is developed. The structure and mechanical properties of the obtained arrays were examined. It is shown that the average grain size in fibers is 73 nm; compressive strength is 12 ± 1 MPa, that can be comparable and even several times higher than the strength of some granulated absorbents based on active aluminium oxide. In case of adding Al2O3 into the structure the characteristics of produced material significantly decrease. [ABSTRACT FROM AUTHOR]

A method for the preparation of novel nanostructured zirconia ceramics from natural zirconia mineral-- baddeleyite--using CaO as the stabilizer is described in the present work. Optimal synthesis conditions, including calcia content, planetary mill treatment regime, sintering time and temperature, corresponding to the highest values of hardness H, Young modulus E, and fracture toughness KC are found. The values of the mechanical properties H = 10.8 GPa, E = 200 GPa, and KC = 13.3 MPa m1/2 are comparable with or exceed the corresponding properties of commercial yttriastabilized ceramics prepared from chemically precipitated zirconia. [ABSTRACT FROM AUTHOR]

We discuss how unitarity saturation leads to appearance of a hadron liquid phase at very high temperatures and how the ridge-like structure in the two-particle correlation function can result from the rotation of the transient state of matter. [ABSTRACT FROM AUTHOR]

A method for the identification of charged particles by wide aperture Si -detectors has been investigated based on the employment of pulse -shape discrimination in a silicon p -i-n detector. [ABSTRACT FROM AUTHOR]

An improved LCP identification method based on Pulse shape analyses has been designed, the module “Dual Pulse-Shape Analyzer” has been built and tested and resent experimental results of instrument utilizing have been presented. [ABSTRACT FROM AUTHOR]

Interpretation of unitarity saturation as reflective scattering is discussed. Analogies with optics and Berry phase alongside with the experimental consequences of the proposed interpretation at the LHC energies are considered. [ABSTRACT FROM AUTHOR]

The experimental evidences of the hydrogen subsystem existence in solids and a possibility of its excitation by external influence are described. During occupation of equivalent positions inside metal, hydrogen forms its own subsystem inside a crystallographic lattice, which has the self-frequencies lying outside the phonon spectrum of a crystal. Under the input of the energy, for instance, by means of radiation, excitations of vibration freedom degrees of hydrogen subsystem occur. The following facts give evidence of this: enhanced migration and release of hydrogen isotopes at low temperature from metals under ionizing radiation; super linear dependence of H, D release from metals on electron current density; H, D release both in molecular and atomic forms. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

A nonperturbative mechanism for hyperon polarization in inclusive production is considered. The main role belongs to the orbital angular momentum and the polarization of the strange ss-pairs in the internal structure of the constituent quarks. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper presents the results of studies of the microstructure, phase formation and mechanical properties in non-vacuum electron beam cladded Ti–Ta–Nb alloys. The defect-free surface layer had a content of 21 mass. % Nb and 33 mass. % Ta and a thickness of 2 mm. The samples were investigated using optical microscopy (OM), X-ray diffraction (XRD) analysis, energy dispersive X-ray spectroscopy (EDX). The results of OM and XRD analysis showed that the material inhibits a finely dispersed lamellar structure, which consists of a mixture of martensitic phases (α'+ α') and β phase. The average microhardness is between 300–400 HV and the ultimate tensile strength (UTS) 400–450 MPa. The results of Charpy impact strength test showed that due to the coated surfaced layer the impact strength decreases to 210 J/cm². [ABSTRACT FROM AUTHOR]

Profiles the late physicist, Vladimir L. Solovianov. Educational background; Career highlights; Key contributions in all aspects of physics and research.

The paper presents the results of research on the development of parameters for obtaining weld joints from aluminum alloys 2024 and 5056 in friction stir welding. The results of the conducted work show a rather complex character of dependence of parameters for obtaining weld joints with tensile strength not less than 0.9 on the tensile strength of the base metal. In general, for all the investigated thicknesses of sheet rolled products, it is characteristic to use lower linear welding speeds and high tool rotation speeds. The clamping force of the tool to the material of alloy 2024 workpieces is slightly higher than when welding alloy 5056 samples. The welding of alloy 5056 specimens is characterized by an insignificant increase in the clamping force in the transition from welding specimens 5 and 10 mm thick, which is not typical for alloy 2024. [ABSTRACT FROM AUTHOR]

The samples produced by friction stir welding of 35 mm thick rolled sheets of thermally non-heat-treatable aluminum-magnesium alloy AA5056 were investigated in this work. Macro- and microstructure was studied on metallographic specimens cut in a planar section relative to the welding zone through the thickness of the workpiece. It was found that in the zone of tool inlet the weld metal is extruded, then there is an adhesive interaction of the tool and welded material with its further layer-by-layer transfer, as a result of which the structure is represented by a mixture of material flows along the contour of the tool. [ABSTRACT FROM AUTHOR]

In the present work, the FSW-joint of 35 mm thick aluminum-magnesium alloy AA5056 sheets was investigated. It was observed that the microstructure is represented by a system of separate metal flows along the contour of the tool. This is caused by lower values of pressure in the area of joint formation relative to the material volume in comparison with welding products of smaller thicknesses. The results of microhardness measurements of the weld material and the near-weld area of fixed joints show that in the material of the main structural zones, there is no softening as compared to the base metal. Tensile tests conducted show high mechanical properties of the samples. The average ultimate tensile strength value is about 305 MPa. Deformation of specimens occurs with pronounced discontinuous fluidity or Portevin– Le Chatelier effect. [ABSTRACT FROM AUTHOR]

The paper is devoted to the study of friction stir welded samples, in which the special high-speed steel tool has been broken during the process of their production. The thickness of the samples is equal to 35 mm. It has been observed that after the tool breakage, the pin section separated from the tool remains in the weld. Around the pin, there is the structure modified by the severe thermomechanical action, which made it possible to estimate the size of the material fragmentation zone in the area ahead of the tool. After the breakage, the tool fragment itself has been deformed by the remaining part of the tool, including the shoulders. It resulted in the layering of the upper part of the pin fragment and the crack propagation into the central part of the pin. Based on the data obtained, it was considered that the tool breakage was caused by the excessive axial force, which resulted in the high tangent loads in the area below the shoulders. [ABSTRACT FROM AUTHOR]

The work compares the strength characteristics and microstructure of 2-mm-thick welded joints from Al-Mg alloy AA5056, produced by friction stir welding along and across the workpiece rolling direction. The tests show that the variation of parameters results in the formation of a complex structure, which is determined by the contribution of both mechanical and thermal components. Depending on the rolling direction, the welded joint has different mechanical properties under identical conditions. In the case of the rolling direction coinciding with the friction stir welding direction, the strongest welded joint has the ultimate tensile strength of 328 MPa, which is equal to 98% of the base metal strength. In case of welding in the transverse direction, the ultimate tensile strength of the joint exceeds those of the base metal by 8 MPa and is equal to 333 MPa. According to the conducted experiments it was proved that the structure and strength of friction stir welded joints depends on the workpiece rolling direction, which implies different welding parameters for these cases. [ABSTRACT FROM AUTHOR]

In this work the study of the friction stir welding process of 2 mm thick aluminum alloy AA2024 sheets cut along and across the rolling direction was carried out. The obtained results show that the rolling direction of AA2024 sheet workpieces has a significant effect on the selection of optimal welding modes. It is revealed that at welding across the rolling direction it is possible to achieve the highest values of the ultimate tensile strength in a rather wide range of modes. [ABSTRACT FROM AUTHOR]

In this paper, regularities of the friction stir welding process parameters influence on mechanical properties of welded joints of different thicknesses are investigated. Joints were produced using the same type of tools with a screw-shaped pin. The tests show different dependencies of the joint mechanical behavior on the welding parameters. 2-mm-thick samples are characterized by high values of the ultimate tensile strength and a small variation of those when changing parameters. 10-mm-thick samples are characterized by a lower ultimate tensile strength and a greater variation at changing process parameters. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of rock fracture toughness importance for correct hydraulic fracturing simulations. The parameter characterizes the rock's ability to resist the fracture process. For numerical simulations of the fracture based on the postulates of the failure mechanics, the fracture toughness is one of the determining parameters along with the elastic properties of the rock and the injection conditions. The aim of the paper is to determine how much the fracture toughness affects the fracture length in the numerical model describing the laboratory experiments. The used laboratory setup made it possible to create conditions that determine the actual fracture process. The strength parameters of the model material were measured. In particular the fracture toughness was measured using indentation methods. Numerical model calibrated by the laboratory experiment was used to solve the postulated problem. [ABSTRACT FROM AUTHOR]

Differential cross sections of the 12C+12C and the 13C+12C elastic scattering were measured at the projectile energies 240 MeV (12C) and 250 MeV (13C) up to the largest angles. The positions of the 1st Airy minima known from the former experiments were confirmed. [ABSTRACT FROM AUTHOR]

In the present paper we describe an experiment performed on the reaction 238U + 4He (40 MeV) using a two-arm TOF-E (time-of-flight vs. energy) spectrometer with micro- channel plate detectors and mosaics of PIN diodes. This experiment has aimed at searching for fine structures in the total kinetic energy vs. fragment mass (TKE - M) distributions of binary events, and disclosing rare ternary decay modes others than already known from ternary fission. Details of the procedures of data handling are briefly described as well. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]