bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of a Wind Turbine with Two Moving Masses Using the Galloping Effect
Authors: Selyutsky Yu. D.
Published: April 2024

A wind power plant is considered using the galloping effect, which includes two elastically connected translationally moving bodies: one is a square prism with a permanent magnet rigidly attached to it, and the other is a material point. Electricity is generated by the movement of a magnet in a coil. The influence of the system parameters on the wind speed at which galloping oscillations occur is analyzed. It is shown that a proper choice of parameters makes it possible to significantly expand the range of wind speeds at which periodic regimes exist, in comparison with a system containing one moving body. Approximations are obtained for the amplitudes and frequencies of the limit cycles arising in the system. The evolution of these cycles with a change in the stiffness of the spring between the bodies is studied. It is established that, for certain values of the parameters, the simultaneous existence of two attracting periodic solutions is possible. Conditions are obtained under which the power generated by such a system is greater than the power generated by a system with one moving mass.
Algorithm for Solving Discrete Contact Problems for an Elastic Layer
Authors: Bobylev A. A.
Published: April 2024

The problems of discrete contact between an elastic layer and a rigid punch with unknown areas of actual contact are considered. A variational formulation of the problems is obtained in the form of a boundary variational inequality using the Poincaré-Steklov operator, which maps normal stresses into normal displacements on a part of the elastic layer boundary. To approximate this operator, a two-dimensional discrete Fourier transform is used, for the numerical implementation of which algorithms of the fast Fourier transform are used. A minimization problem equivalent to the variational inequality is presented. As a result of its approximation, a quadratic programming problem with constraints in the form of equalities and inequalities is obtained. To numerically solve this problem, we used an algorithm based on the conjugate gradient method, which takes into account the specifics of the set of constraints. Two-parameter families of punches rectangular in plan with surface relief are constructed. As a result of computational experiments, the existence of a single envelope of contact pressure, a single envelope of normalized contact forces, and a single envelope of the relative values of the actual contact areas of microprotrusions has been established for each family of punches. The shape and position of these envelopes for a family of punches depend on the parameters of the external load and the ratio of the dimensions of the nominal contact area to the layer thickness.
Experimental Study of the Effect of Anisotropy on the Orientation of Breakouts in Wells
Authors: Ustinov K. B. , Karev V. I. , Kovalenko Yu. F. , Barkov S. O. , Khimulia V. V. , Shevtsov N. I.
Published: April 2024

On rock samples taken from the Cenomanian horizon of the PK1 formation of the gas and gas condensate fields of the Arctic shelf of Russia, direct physical modeling of the formation under the action of equal component stresses of breakouts in wells directed along the normal and along the occurrence was carried out. In the first case, the shape of the breakouts was cylindrical, and in the second case, in the form of two caverns. Such a form of breakouts, when interpreting well logging, is usually assumed to be caused by an unequal component stress field, which obviously does not correspond to the results of the experiments. Independent experiments were also carried out to determine the anisotropy of the elastic and strength properties of the studied rock. It was found that the studied rock has a specific type of strength anisotropy, not directly related to the weakening along the bedding. It is shown that this type of strength anisotropy can lead to the formation of breakouts of the observed shape. The main purpose of the article is to draw attention to the fact that stress anisotropy is not necessarily the main or only cause of the observed breakouts in wells. The results can be used in the design and development of hydrocarbon fields and underground gas storages, as well as in the interpretation of well measurements to determine the natural stress field in the Earth's crust.
Control of the Rotation of a Solid (Spacecraft) with a Combined Optimality Criterion Based on Quaternions
Authors: Levskii M V.
Published: April 2024

The dynamic problem of the optimal rotation of a rigid body (for example, a spacecraft) from an arbitrary initial to a designated final angular position in the presence of restrictions on the control variables is studied. Rotation time is not fixed. To optimize the rotation control program, a combined quality criterion is used, the minimized functional combines the energy costs and the duration of the maneuver in a given proportion. Based on the L. S. Pontryagin maximum principle and quaternion models of controlled motion of a solid, a solution to the problem was obtained. The reorientation optimality conditions are written in analytical form, and the properties of optimal rotation are shown. To construct an optimal rotation program, formalized equations and calculation formulas are written. Optimal control is presented in the form of a synthesis. The control law is formulated as an explicit dependence of the control variables on the phase coordinates. Analytical equations and relations for finding the optimal motion are given. Key relationships are given that determine the optimal values of the parameters of the rotation control algorithm. A constructive scheme for solving the boundary value problem of the maximum principle for arbitrary rotation conditions (initial and final positions and moments of inertia of a rigid body) is also described. For a dynamically symmetric rigid body, a closed-form solution of the reorientation problem is obtained. A numerical example and the results of mathematical modeling are presented, demonstrating the practical feasibility of the developed method for controlling the attitude of a spacecraft.
The Problem Solution on the Propagation of a Griffith Crack Based on the Equations of a Nonlinear Model
Authors: Bulygin A. N. , Pavlov Yu. V.
Published: April 2024

On the basis of a nonlinear model of deformation of a crystalline medium with a complex lattice, the problem of the stationary propagation of a Griffith crack under the action of homogeneous expanding stresses is posed and solved. It is shown that the stressed and deformed states of the medium are determined both by external influences on the medium and by the gradients of the optical mode (mutual displacement of atoms). The contributions from these factors are separated. Finding the components of the stress tensor and macro-displacement vector is reduced to solving Riemann–Hilbert boundary value problems. Their exact analytical solutions are obtained.
A New Method for Relaxation of Elastic Stresses During the Growth of Heteroepitaxial Films
Authors: Koryakin A. A. , Kukushkin S. A. , Osipov A. V. , Sharofidinov Sh. Sh. , Shcheglov M. P.
Published: April 2024

In the article, using the example of growing aluminum nitride (AlN) on (110) orientation silicon (Si) with a silicon carbide (SiC) buffer layer, a method for growing a new type of substrates is developed which makes it possible to obtain mechanically unstressed semiconductor heterostructures. A specific feature of the synthesis of this kind of substrates is that the SiC layers used for the growth of AlN films were synthesized by the coordinated atoms substitution method. When this method of growth is used in the Si substrate, some of the Si atoms are replaced by carbon atoms. As a result of the substitution of atoms, the initially smooth Si(110) surface transforms into a SiC surface covered with prism-like growth figures, one side of which is the (111) face and the other is the face. These faces are "substrates" for the further growth of semipolar AlN. The structure and morphology of AlN films have been studied by X-ray diffraction, electron microscopy, and Raman spectroscopy. It was found that the AlN layer is formed by intergrown hexagonal microcrystals, which grow in two directions, and for both orientations of the crystals the following relation is approximately satisfied: AlN || Si(110). It is shown that the half-width of the X-ray rocking curve (FWHM) for the diffraction peak from AlN microcrystals, averaged over the area of the sample, is 20 arc minutes. Raman spectroscopy and X-ray diffraction studies have shown the almost complete absence of mechanical stresses in the AlN layer. A theoretical model is constructed to explain the presence of two orientations of the AlN film on SiC/Si(110) found in the experiment, and a method for controlling their orientation is proposed. It is shown that this morphology of the AlN film makes it possible to use it as a buffer layer for the growth of heterostructures based on gallium nitride and aluminum nitride.
Fundamental Solutions of the Equations of the Oscillation Theory for Anisotropic Elastic Media
Authors: Ilyashenko A. V.
Published: April 2024

The construction of fundamental solutions in R3 for the equations of harmonic vibrations in the theory of elasticity of anisotropic elastic media is carried out. Solutions are constructed in the form of multipole series. Theorems on the convergence of series in the topology of compact convergence in R3/0 are proved. The problems on constructing some singular solutions of the theory of vibrations of an anisotropic body are discussed. The fundamental solution of the oscillation equations for an isotropic medium is obtained in a closed form.
Torsion of Rods Made of Hardening Material Subjected to the Influence of Variable External Pressure under a Linearized Plastic Flow Rule
Authors: Mironov B. G. , Mironov Yu. B.
Published: April 2024

The article deals with the torsion of rods made of an anisotropically hardening rigid-plastic material under the linearized plastic flow rule. It is assumed that the rod is subject to external pressure, which varies linearly along the generatrix. The components of the stress and strain tensors that describe the limiting state of the rod are determined.
Problem on Maintaining Contact of a Low-Mass Research Probe with Asteroid
Authors: Lavrovskii E. K.
Published: April 2024

The problem on maintaining contact of a body of small mass with the surface of a homogeneous, symmetrical asteroid rotating by inertia is investigated. Two opposite forces: the holding gravitational force of the asteroid and the repulsive centrifugal force act on the body. The problem is considered in a restricted formulation. Critical contact points are investigated for on a number of surfaces with an axis of symmetry. It is also shown that the movement of the body over the surface of the asteroid can contribute to its more reliable contact with the asteroid.
Lead Phosphates (Pyromorphite and Phosphohedyphane) from the Oxidation Zone of Baryte-Lead Ores in the Ushkatyn-III Deposit, Central Kazakhstan
Authors: Brusnitsyn A. I. , Perova E. N. , Loginov E. S. , Platonova N. V. , Panova L. A.
Published: April 2024

The paper describes Ca-Pb phosphates—pyromorphite and phosphohediphane from the oxidation zone of barite-lead (calcite-barite-galena) ores of the Ushkatyn-III deposit in Central Kazakhstan. Both minerals occur equally frequently within the deposit. Lead phosphates coexist with minerals as almost unaffected by surface changes in ores (galena, pyrite, barite, calcite, rhodochrosite, chamosite, and others), so with minerals of highly oxidized ores (cerussite, montmorillonite, kaolinite, goethite, and others). As the processes of supergene processes develop (during the transition from weakly to strongly oxidized ores), the compositions of newly formed phosphates change regularly in the following consequence: phosphohedifane → rhythmically zonal Ca-Pb phosphate → pyromorphite. At the same time, the habit (and appearance) of mineral crystals changes from dipyramidal-prismatic through elongated prismatic (barrel-shaped) to pinacoidal-prismatic (short-columnar). Crystallization of pyromorphite is possible already at very low concentrations of lead, phosphorus and chlorine in solution. The main source of chlorine is groundwater, and phosphorus is coming from the organic matter of the soil cover overlying ore-bearing deposits. Peculiarities of the chemical composition and crystal structure of Ca-Pb phosphates, as well as the nature of their mineral associations, suggest the presence of a discontinuity in isomorphic miscibility in the series pyrofmorphite–phosphohedifane and phosphohedifane–chlorapatite.
Minerals Named after Alumni and Staff Members of Saint Petersburg Mining University (to the 250th Anniversary of St. Petersburg Mining University)
Authors: Krivovichev V. G. , Smolensky V. V.
Published: April 2024

The article is dedicated to the 250th anniversary of the St. Petersburg Mining University (Mining Institute). History of the Mining University is closely connected with the names of scientists who have made a huge contribution to the development of mineralogy and adjacent sciences. The names of 57 alumni and staff members of the Institute have forever entered the history of mineralogy. 62 mineral species are named in their honor. The article summarizes the scientific interests and achievements of teachers, scientists and mining engineers, after whom the minerals were named.
Strontium and Barium Minerals in Alkaline Rocks of the Bolshetagninsky Ijolite-Syenite-Carbonatite Massif (Southwestern Margin of the Siberian Craton)
Authors: Savelyeva V. B. , Bazarova E. P. , Khromova E. A.
Published: April 2024

The paper displays data on Sr- and Ba-bearing minerals occurring in melteigite, ijolite, urtite, and nepheline syenite of the Bolshetagninsky ijolite-syenite-carbonatite massif. At the magmatic stage, strontium enters as an isomorphic admixture into calcite (SrO = 0.5–1.9 wt %) and fluorapatite (SrO = 0.6–2.6 wt %), while barium mainly enters in phlogopite and annite. Zonal phlogopite in urtite contains up to 8.4 wt % BaO (24 mol. % of kinoshitalite component); interstitial calcite in the same rock contains small ingrowths of barytocalcite. Stronalsite, strontianite, crichtonite, henrimeyerite, barite, celestite, Sr-bearing fluorcalcipyrochlore, Sr-bearing muscovite, and epidote have crystallized at the high-temperature postmagmatic stage. In the exocontact zone of the carbonatite stock, ijolite and nepheline syenite underwent biotitization, carbonatization, and K-feldspathization, followed by chloritization and formation, in some spots, of hyalophane and celsian segregations and veinlets. The formation of Ba-bearing muscovite and Ba-bearing manganese hydroxides took also place at the low-temperature hydrothermal stage. The presence of hyalophane and celsian in altered alkaline rocks is a peculiarity of the Bolshetagninsky massif, indicating the low activity of \({\text{SO}}_{4}^{{2 - }}\) in hydrothermal solutions.
Fluoborite in the Ore-Bearing Skarns of the Aktash Magnetite-Polymetallic Deposit in the Karamazar (Northhern Tajikistan)
Authors: Yatimov U. A. , Maslennikov V. V. , Rassomakhin M. A. , Hvorov P. V. , Lebedeva S. M.
Published: April 2024

Fluoborite has been for the first time discovered in magnetite-bearing skarns at the distance of few meters from the contact between dolomite-carbonate and granodiorite of the Aktash deposit. Fluoborite, Mg3(BO3)(F,OH)3, was revealed and studied with optical and electron microscopy and determination of its chemical composition (wt %): MgO 63.29–64.56, F 18.35–21.91, B2O3 18.44–18.58, H2O 4.02–5.62, –O=F2 7.73–9.23, total 99.27–99.85. The identity of the mineral has been confirmed by X-ray phase analysis (reflections 7.702, 4.445, 3.584, 2.908, 2.417, 2.22, 2.133, 1.806, 1.763, 1.678, 1.635, 1.554, 1.534, 1.485, 1.477 Å) and Raman spectroscopy (Raman spectra with bands 952, 848, 534, 423, 345, 239 and 175 cm–1). Radial-columnar aggregates of fluoborite occurring in serpentine are partially replaced by fluorite, and some tops of its crystals are overgrown by magnetite metacrystals. These magnetite metacrystals contain poikilites of fluoroborite and fluorite.
Previously Unpublished Documents and Memories about A.E. Fersman: to the 140th Anniversary of the Birth
Authors: Voytekhovsky Yu. L.
Published: April 2024

For the first time the article publishes letters of A.E. Fersman (November 1938–February 1945) and E.M. Fersman (August 1945–January 1964) from archive of D.P. Grigoriev stored in the Russian Mineralogical Society, and memories of V.N. Florovskaya about meetings with A.E. Fersman (1937–1945) and P.N. Chirvinsky (1937–1954) at the Afrikanda deposit, the Tietta scientific station in Khibiny and later in Moscow, Leningrad, Perm. The publication is timed to the 140th anniversary of the A.E. Fersman date of birth. Attention is drawn to the importance of preserving and researching personal archives when studying the history of science.
Typification of Rare-Metal Alkaline Granites
Authors: Marin Yu. B. , Smolensky V. V. , Beskin S. M.
Published: April 2024

A new variant of classification of rare-metal alkaline granites is proposed with allocation of three types, essentially differing on chemical and mineral composition and features of their Rare Metal - Rare Earth specialization. The average composition of rocks from reference massifs of each type of rare-metal alkaline granites is given, the selected types are briefly characterized and their most important indicative features are emphasized.
Сhromite-Ulvöshpinel Series of Minerals from Alkaline Picrite-Basic Rocks of the North Siberian Platform and Their Oxythermobarometry
Authors: Okrugin A. V.
Published: April 2024

The typochemical features of spinels forming continuous series from Al–Cr spinels to Ti-magnetite and ulvöshpinel from basic-ultrabasic rocks of the North Siberian platform are considered. Their comparative characteristics are carried out with similar minerals of alkaline basalts of oceanic islands and Lunar marine basalts on the modified 3D-diagram Al–Cr–(Fe3+ + 2Ti)–Fe2+ proposed by the author. The identification of a continuous isomorphous series from chromian spinel to ulvöspinel is one of the mineralogical indicators of a possible paragenetic relationship between picrite-basalt, alkaline olivine-basalt, alkaline-ultrabasic, and kimberlite formations in the North Siberian platform. Using the Ballhaus-Berry-Green olivine-chromespinel oxythermobarometer, it was shown that for the studied rocks of the North Siberian platform, the oxygen volatility lg fO2 is 2–4 orders of magnitude higher than that specified by the fayalite-magnetite-quartz (FMQ) buffer and corresponds to the oxidation state of platinum-bearing dunite-clinopyroxenite associations of rocks of the Ural-Alaskan and Aldan types.
Industrial Regional Space in the “Core–Periphery” System in Russia
Authors: Makushin M. A. , Demidova K. V. , Gorjachko M. D.
Published: April 2024

Abstract—the center-periphery model is used to explain modern geographical processes and phenomena, but nobody systematically studies the position of Russian regions in the system of center-peripheral relations. The current study is aimed at eliminating this gap. The purpose of research is to test the methodology for identifying central and peripheral regions in the Russian industrial space and the main features of the industrial development of different types of regions. Statistical and mathematical-statistical research methods based on Rosstat data in 2005–2020. The sample included 83 subjects of the Federation (with the exception of the Republic of Crimea and Sevastopol), for which there are comparable data series. All regions are assigned to one of the types: core, sub-center, sub-periphery, periphery. The nuclear regions include highly industrial regions with a high base and competitive industries. The group of sub-center regions includes medium-sized industrial regions with high dynamics. The sub-periphery concentrated 40% of the Russian regions. Regions of this group were further divided into subtypes according to the dynamics of industrial development and specialization. The periphery was divided into 2 subtypes: 1) depressed regions with a high base shrinking in the post-soviet period; 2) underdeveloped regions with a low base. It is noted that shifts in the center-periphery system are inertial. Over the past 15 years, the concentration of industrial production in cores and sub-centers has increased, but the investment dynamics is higher in sub-centers. The role of old-industrial sub-peripheral regions is most strongly reduced. The role of the underdeveloped periphery in industrial employment of the population is increasing. The findings can be used to further adjust the regional industrial policy and develop a strategy for the spatial development of Russia.
Morphology and History of the Upper Kama and Kolva Valleys in the Late Glacial and Holocene
Authors: Chernov A. V. , Nazarov N. N.
Published: April 2024

Abstract—The article deals with the evolution of the river network of the northern Kama region, a region that has experienced the influence of a late quaternary glacier. This glacier was located to the north, in the basins of the upper Vychegda and Pechora, but the influence of its meltwater was reflected in the restructuring of the river network of the lowland Kama-Vychegda interfluve. In order to find out the extent of this influence in the conditions of postglacial warming, the article compares the floodplain-channel complexes of the Upper Kama and Kolva formed in the Holocene. In the upper Kama in the late Quaternary, there was a flow of water from Vychegda along the rivers North and South Keltma; there were no additional water flows to the Kolva River, located 30 km to the east. It turned out that the parameters of the floodplain-channel complexes of both rivers are identical. Consequently, the flow of the Vychegda waters into the Kama was carried out not in the late Quaternary-Holocene time, but earlier, and it was no longer reflected on the channels and floodplains of the Kama and Kolva. At the same time, on the Kama – Vychegda interfluve there are traces of other watercourses that have now disappeared, formed during the melting of the glacier. The origin and time of the formation of these “blind” watercourses have yet to be determined.
Calculation of Seasonal Erosion on the Oka River Riverbanks Using Geodetic Modeling
Authors: Vorob’ev A. Ju. , Kadyrov A. S. , Lokteev D. S. , Burgov E. V. , Balobina A. A.
Published: April 2024

Abstract—Directed erosion of riverbanks stands out among the dangerous geomorphological processes on large lowland rivers. In the middle reaches of the Oka river, horizontal channel deformations make a significant contribution to regional lithodynamics and the reduction in the area of floodplain lands. We carried out field geological and geomorphological studies in the valley of this large tributary of the Volga, which revealed the complex facies architecture of the floodplain. The forecast for riverbank erosion near the city of Ryazan has recently declined due to the unstable water regime of the Oka river. For a detailed assessment of the consequences of destabilization of the coastal slopes, their surface was surveyed using a total station and aerial photography from a UAV. Regular observations of erosion by the seasons of the hydrological year allowed us to obtain actual data on the redistribution of soils along the height of the slope. We have found that erosion in summer low water is three times weaker than during high water. The predominance of collapses of the uppermost (0.0–2.0 m from the day surface) part of the erosion fronts was also revealed. The article also discusses possible reasons for the mobilization of the geological filling of the river bank, arising from local differences in the Pleistocene-Holocene evolution of the morpholithic system of the Oka river floodplain and the fixation of geological information in it.
The Impact of Modern Logging on Soil Disturbance, the State of Ground Cover and the Subsequent Regeneration of Trees in Boreal Forests of Russia
Authors: Ilintsev A. S.
Published: April 2024

Abstract—The article presents materials for studying the physical properties of the upper horizons of the soil, the species diversity of the living ground cover and the natural regeneration of trees in 1–15 years old clear-cuttings. A noticeable compaction of the soil is observed in the ruts of the passage of machines, mainly in the thickness of the soil 0–10 cm, but not in the between ruts sand the cutting strips. We found that the physical properties (bulk density, total porosity and aeration porosity) of the upper soil horizons depend on the age of cutting and the study site (p 0.01). Soil compaction in the ruts decreases 9–15 years after logging to indicators in sites where the movement of machines was not carried out. The overgrowth of damaged sections in clear-cuts occurred through ruderal species and species with wide ecological amplitudes to environmental factors. This overgrowth stabilised 15 years after logging when the biodiversity level approached untouched stands. The regeneration of clear-cuts is mainly deciduous such as birch and aspen that mainly grew in the cutting strips. In the ruts and the between ruts, the amount of undergrowth is 2–7 times less than in cutting strips.
Structure of Shock Wave in Oxygen
Authors: Erofeev A. I. , Rusakov S. V.
Published: April 2024

The results of numerical study of relaxation processes in oxygen at high temperatures are presented. Collisions of particles (atoms and molecules) are described by the molecular dynamics methods based on trajectory calculations within the framework of classical mechanics. A complex of programs for calculating the relaxation processes in mixtures of high-temperature gases involving internal modes that describe rotational and vibrational motions in molecules and molecular dissociation and atomic recombination in the presence of a third body is described. The relaxation process is described with reference to variation in the parameters in a mixture of atomic and molecular oxygen with various initial temperatures of the translational and internal modes. The results of calculations of the structure of shock wave in oxygen with the maximum translational temperature on the front higher than 5000–11 000 K are given. The results obtained are compared with experimental data.
Formation of Three-Dimensional Internal Waves behind a Body in Motion in a Stratified Viscous Fluid
Authors: Matyushin P. V.
Published: April 2024

A uniform motion of a disk in horizontal direction along its axis of symmetry in a stratified viscous fluid at rest is studied. The disk generates three-dimensional internal gravity waves occupying the entire volume between the disk and the location of its start. The waves are observed using two-color, beta-plus visualization of the vortex flow structure calculated within the framework of the system of Navier–Stokes equations in the Boussinesq approximation. The results of the study complete considerably the earlier-published mechanism of the formation of half-waves above the axis of symmetry of the disk, where emphasis was placed on the periodic process of generation of deformed vortex rings above the location of the disk start. Their generation is due to gravitation and shear instabilities, when the left semi-ring is transformed into a half-wave of depressions or crests, while the right one vanishes with time. In this paper it is established that the left parts of the right odd semi-rings are transformed into the axial parts of the crest half-waves.
Effect of a Conical Extension on Aerosol Sedimentation in the Case of Acoustic Small-Amplitude Oscillations in a Tube
Authors: Shaidullin L. R. , Fadeev S. A.
Published: April 2024

The effect of acoustic low-intensity oscillations in a homogeneous tube and in a tube with a conical extension is experimentally investigated for the same resonator volumes. The resonator shape is shown to have an effect on the oscillation spectrum and intensity and the pressure wave shape at constant values of the resonance frequency and the piston displacement amplitude. An increase in the resonator Q-factor is observable, when the resonator has a conical extension. An accelerated aerosol sedimentation in tubes is revealed in the case of acoustic oscillation with the resonance frequency. In the presence of a conical extension the aerosol drop concentration is reduced by a factor of 1.2 more rapidly than in the case of a uniform tube and three times more rapidly as compared with natural sedimentation. The results obtained can be used for increasing the efficiency of acoustic methods of gas purification from the disperse phase
Radiative characteristics of shock-heated air in the visible and infrared regions of the spectrum
Authors: Kozlov P. V. , Zabelinskiy I. E. , Bykova N. G. , Gerasimov G. Y. , Levashov V. Yu.
Published: April 2024

The integral and temporal spectral characteristics of shock-heated air in the shock wave velocity range from 7.35 to 10.4 km/s at a pressure p0 = 0.25 Torr before the shock wave front were measured. The experiments were carried out on the DDST-M shock apparatus of the Moscow State University Institute of Mechanics. The radiation wavelength range  = 600-1100 nm, corresponding to the visible and near-infrared spectral regions, in which the main contribution to the radiation is provided by atomic nitrogen and oxygen lines, was investigated. The analysis of the obtained integral in time spectrograms of radiation is performed. The peculiarities of time oscillograms for the most typical atomic lines of the spectrum are highlighted. The measurement data are compared with experimental data of other authors.
STEADY-STATE AMPLITUDE OF NONLINEAR OSCILLATIONS OF A GAS BUBBLE IN A LIQUID UNDER THE ACTION OF PERIODIC EXTERNAL PRESSURE AT RESONANCE
Authors: Petrov A. G.
Published: April 2024

The forced nonlinear oscillations of a gas bubble in a liquid are studied when the frequency of oscillations of the external pressure of the liquid is equal to the natural frequency of the bubble oscillations (resonance). Using the averaging method, a simple formula is derived for the dependence of the amplitude of oscillations of a gas bubble on the amplitude of the external pressure and the thermophysical characteristics of the gas and liquid viscosity. Its good agreement with numerical calculations is shown up to the value of the amplitude of oscillations of the bubble radius comparable with its equilibrium value.
Frequencies and profiles of flexural-gravity waves
Authors: Kalinichenko V. A.
Published: April 2024

New results of experiments on the effect of a floating thin plate on the regularization of a standing Faraday gravity wave on the free surface of water in a rectangular vessel are presented. It is shown that an increase in the thickness of a floating plate significantly affects both the natural frequency of oscillations of the hydroelastic system and the shape of the profiles of the observed standing flexural-gravity waves. When the plate thickness is below the critical value, the waveform is described by the theory of non-linear gravity waves; at large thicknesses, the “dry beam” approximation should be used as approximating dependencies.
Nonuniqueness and stability of the water boiling surface in a geothermal reservoir
Authors: Tsypkin G. G.
Published: April 2024

The stability of the boiling surface of water at rest in high-temperature rock, when the domain of ​​water is located above the domain of vapor is investigated. It is shown that the solution is not unique and there are two positions of the interface. As the parameters change, the solutions approach each other and the solutions seases to exist. The normal mode method was used to study the stability of the positions of the interface. A dispersion equation was obtained, which was studied numerically and analytically. It is shown that the transition to instability occurs with a decrease in pressure in the vapor region or an increase in pressure in the water region. Bifurcation diagrams are presented, illustrating the merging and nonexistence of solutions, and parts of the branches corresponding to stable and unstable flow regimes are highlighted.
Turbulent Schmidt and Prandtl Numbers in the Boundary Layer on a Wall with Film Cooling when a Foreign Gas is Injected through a Porous Insert
Authors: Lushchik V. G. , Makarova M. S. , Popovich S. S.
Published: April 2024

Variations in the turbulent Schmidt and Prandtl numbers in the boundary layer on a wall with film cooling when helium is injected into xenon flow through a porous insert is investigated numerically using the three-parameter RANS turbulence model supplemented with transport equations for turbulent heat and mass transfer. The results obtained are compared with calculated data for constant turbulent Schmidt and Prandtl numbers.
Ecology of Brambling Fringilla montifringilla L. in the North of Western Siberia
Authors: Ryzhanovsky V. N.
Published: April 2024

The features of the ecology of brambling at the northern limit of their range in the Priobskaya forest tundra are considered. The nesting density remains high, locally 50–100 pairs/km2, up to the boundary of the distribution of coastal forests and floodplain woodlands along the 67th parallel. Habitats suitable for nesting brambling are also available to the north, but birds are few in number. Biotopic conditions do not significantly limit the progress to the north. The brambling have no adaptations to Subarctic conditions. This is a medium- and north-taiga species that develops the forest tundra as it warms and thickens the woodlands.
Physiological and Biochemical characters of Nigrospora gorlenkoana Novobr. Occurring on Cereals
Authors: Orina A. S. , Gavrilova O. P. , Gagkaeva T. Yu.
Published: April 2024

The ubiquitous distribution of Nigrospora fungi in the mycobiota of cereal grain in Russia has been established. Fourteen Nigrospora strains using phylogenetic analysis of ITS, tub, and TEF loci were identified as N. gorlenkoana, first identified in Russia. Morphological characteristics of N. gorlenkoana strains were analyzed on various nutrient media. A wide temperature range of 15–25°C was optimal for growth of N. gorlenkoana strains. This probably contributes to the wide distribution of N. gorlenkoana in nature. The pathogenicity of N. gorlenkoana strains to cereal crops was shown. The fungal strains reduced length of wheat and barley seedlings on average 48% and 39% compared to the control, respectively.
East Fennoscandian Ecological Corridors and Their Role in the Formation of the Modern Mammal Fauna of the Region
Authors: Fyodorov F. V. , Danilov P. I. , Panchenko D. V.
Published: April 2024

The article deals with the functioning of ecological corridors as passages to central regions of Eastern Fennoscandis for mammals characterized by population oscillations, high migratory activity, and the consequential dispersal beyond the historical distribution ranges (wild boar, roe deer). We also discuss the invasions of new species in Eastern Fennoscandia as a result of introductions and natural dispersal (muskrat, American mink, Canadian beaver, racoon dog, white-tailed and sika deer).
Aircraft Collisions With Birds (Order Falconiformes and Accipitriformes)
Authors: Silaeva O. L. , Pedenko A. S.
Published: April 2024

Statistical data on aircraft collisions with birds of prey (Falconiformes and Accipitriformes) are analysed. The basis of the analysis was the results of the IPEE RAS study. The reasons and factors attracting birds of prey to airfields are considered. In the period from 2005 to 2022 seven species of birds of prey involved in 29 collisions with aircraft were identified. The largest number of birdstrike occur with common kestrel Falco tinnunculus and common buzzard Buteo buteo. The most collisions occur on the airport or in its vicinity; there is a 4.3 times more strikes by taking off than by landing. From raptor birds’ collisions suffer mainly engine and wing structure. Recommendations are given to control birds’ behaviour for minimizing strikes with birds of prey at the airfield.
Life Cycles of Lung Helminths in Terrestrial Mammals from Eastern Europe and Their Biological Classification
Authors: Movsesyan S. O. , Nikoghosian M. A. , Petrosian R. A. , Terenina N. B. , Panayotova-Pencheva M. S. , Demiaszkiewicz A. W. , Voronin M. V. , Kuznetsov D. N. , Vardanyan M. V.
Published: April 2024

This article has been prepared based on the results of many years of the authors' studies in the framework of scientific cooperation between Academies of Science of Russia, Armenia, Bulgaria and Poland. It is a continuation of one published in Annals of Parasitology: Biodiversity of Lung Helminths in Terrestrial Mammals from Eastern Europe (2021). To determine the biological diversity of lung helminths various vertebrate hosts were studied, including 7 species from Armenia, 13 from Russia, 7 from Bulgaria and 10 from Poland, as well as many invertebrate potential hosts, mainly land mollusks. Three types of development cycles were found to be characteristic for lung helminthes: 1 – Nematodes from family Dictyocaulidae developing in a direct way without using intermediate hosts, geohelminths or monoxenous type of development. 2 – Those nematodes life cycles of which include intermediate hosts which are mainly land mollusks. These are species from family Protostrongylidae – biohelminths, dixenous type. 3 – Life cycles also include intermediate hosts, but here they are vertebrate. This type includes cestodes Echinococcus granulosus and Alveococcus multilocularis – biohelminths, dixenous type.
Transformation of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans Congener Profile during Bioaccumulation in Free-Range Chicken Eggs
Authors: Kudryavtseva A. D. , Shelepchikov A. A. , Mir-Kadyrova E. Ya. , Brodsky E. S.
Published: April 2024

The PCDD/F profiles in free-range chicken eggs and corresponding soils from private households in Vietnam were compared. The main trend in the change in the profile of PCDD/F congeners during bioaccumulation in eggs is the relative increase in the contributions of low-chlorinated congeners and the decrease in the contribution of OCDD. Differences in the profile of hexachlorinated congeners in eggs and soil may indicate additional sources of PCDD/F in eggs other than soil.
Forest Biogeocenoses in the Area of Brown Forest Soils of the Western Caucasus
Authors: Uligova T. S. , Tsepkova N. L. , Rapoport I. B. , Gorobtsova O. N. , Gedgafova F. V. , Tembotov R. Kh.
Published: April 2024

Vegetation and brown forest soil of different types of forests of the southern and northern macroslopes of the Main Caucasian Ridge were studied, special attention was paid to soil fauna (earthworms), microbial and enzymatic activity. A comparative analysis of the main components of forest biogeocenoses (plant communities, earthworms, microbial and enzymatic activity of the soil) of the southern and northern macroslopes of the Main Caucasian Ridge located in the Caucasian State Natural Biosphere Reserve and natural monuments “Guam Gorge” and “Colchian boxwood Massif” was carried out. The assessment of the plant diversity of various types of colchian forests of the southern and northern macroslopes is given. The similarity of the structure of plant communities, the population of earthworms, their species richness, as well as the most important indicators of the biological activity of the soil of the southern and northern macroslopes has been established. A close correlation between the indicators of biological activity of brown forest soil with the diversity of vegetation and the number of earthworms is shown.
Shell Amebas of the Natural and Historical Park “Bitsevsky Forest”, Moscow
Authors: Bobrov A. A.
Published: April 2024

For the first time in protozoology, research was carried out on the fauna of testate amoebae in a city park. One hundred and nine species and infraspecific taxa of this group of free-living protozoa were found in various types of habitats in the Bitsevsky Forest park in Moscow. To assess the species diversity of testate amoebae, samples were taken from tree hollows; small oligo-mesotrophic swamps; epiphytic mosses from tree trunks; mosses on deadwood; bottom samples from reservoirs; soil samples near tree trunks, as well as directly in the area of the Yasenevo park estate. Various ecological groups of testate amoebae have been identified, the richest communities of eurybionts inhabited soils, as well as mosses on deadwood. Bottom sediments of manor ponds were inhabited mainly by hydrophilic species of the genus Difflugia.
Developmental Stability, Population Dynamics and Climate Change, with Particular Reference to the Common Shrew (Sorex araneus L., 1758) in Central Siberia
Authors: Zakharov V. M. , Trofimov I. E. , Yakushov V. D. , Sheftel B. I.
Published: April 2024

We examine temporal variation in a measure of developmental stability, the degree of fluctuating asymmetry of the characters of skull morphology, of the common shrew (Sorex araneus L., 1758) in Central Siberia. Four-year cycles in this population in the last century were accompanied by significant changes in the level of developmental stability. Population fluctuations under the climate change conditions in this century commonly occur without essential changes in developmental stability. Deterioration of developmental stability takes place occasionally in case of adverse overpopulation impact in the year of peak population abundance that is beyond the certain threshold level increased due to the climate change.
Morphological Diversity of the Skull and Lower Jaw of Three Species of Shrews (Eulipotyphla, Sorex) During Depressions and Peaks of Abundance
Authors: Puzachenko A. Yu. , Kupriyanova I. F.
Published: April 2024

Ecological conditions can influence the individual development of organisms and morphological variability at the population level. The dimensions and proportions of the skull and lower jaw of immature shrews (Sorex araneus, S. caecutiens, S. minutus) captured in August in overgrown clearings in the middle taiga of north-eastern Europe were dependent on the stage of abundance (“pikes” or “depressions”). For all three species belonging to the same taxocenosis, a statistically significant decrease in skull and jaw measurements was observed against a background of high abundance in captures, and multidimensional morphological niches corresponding to different stages were significantly separated. The parameters of morphological diversity - entropy and a measure of self-organisation were depended on the amplitude of fluctuations in species occurrence, but varied within limits characteristic of mammals. Together with Dehnel’s phenomenon, natural population fluctuations may be one of the main factors determining the nature of the dynamics of individual development and the spatio-temporal variability of morphological diversity in shrews.
Absence of the “Absences”: the Engler-Hengl Approach in Species Distribution Modelling
Authors: Ogurtsov S. S.
Published: April 2024

The possibilities of creating artificial absence points (pseudo-absences) to build species distribution models are considered. An approach proposed by Robin Engler and adapted by Tomislav Hengl is described, which takes into account habitat suitability indices and distances to presence points to create pseudo-absences. Using the example of bilberries (Vaccinium myrtillus) in the Central Forest Nature Reserve and its buffer zone, generalized linear models based on the Engler-Hengl design, traveled tracks and distances to presence points are compared, as well as a model built using the maximum entropy method. The results obtained indicate the superiority of the model based on the Engler-Hengl approach both in terms of quality assessments and in terms of the realism of the constructed spatial distribution maps.
Anatomical Structure and Phytochemical Analysis of the Leaf, Stem and Root of Hydrangea Tree (Hydrangea arborescens L.)
Authors: Murzabulatova F. K. , Pupykina K. A. , Krasyuk E. V. , Polyakova N. V. , Shigapov Z. Kh.
Published: April 2024

The relevance of the study is due to insufficient knowledge of the biological characteristics of hydrangeas. The aim of the research was to identify the anatomical and diagnostic features, as well as the chemical composition of the arborescent hydrangea (Hydrangea arborescens L.) from the collection of the South Ural Botanical Garden-Institute of the Ural Federal Research Center of the Russian Academy of Sciences. As a result of the research, it was found that the diagnostically significant features of the leaf of this type of hydrangea are the structure of the cells of the epidermis of the upper and lower sides of the leaf, the presence of an anomocytic stomatal apparatus on the lower side of the leaf, crystalline inclusions of calcium oxalate in the form of rafids on the upper and lower sides of the leaf, and simple hairs with coarse warty surface, multicellular base, as well as simple sinuous hairs on the underside of the leaf. Phytochemical analysis of leaves, stems and roots confirmed the presence of coumarins, ascorbic acid and tannins in them, and flavonoids in leaves. It has been established that the highest content of ascorbic acid (0.28 ± 0.014%) and tannins (7.13 ± 0.639%) is observed in the leaves of Hydrangea arborescens, coumarins in terms of umbelliferone in the roots (0.41 ± 0.007%), and the content of flavonoids in the leaves was 1.14 ± 0.048%.
Iron Accumulation of Halophytes on the White Sea Littoral Zone
Authors: Terebova E. N. , Pavlova M. A. , Oreshnikova N. V.
Published: April 2024

The accumulation of iron in halophytic species Triglochin maritima L., Plantago maritima L., Aster tripolium L. and Zostera marina L. was studied in this research. Littoral soils are not contaminated with iron (6–16 g/kg). Seawater, on contrary, contains high concentrations of iron (0.04–0.32 mg/l). Halophytes accumulate iron to supervalues (6.49–71.63 г/кг), 93% of metal is found in rhyzomes. The reasons for this phenomenon are discussed. Halophytes of the White Sea littoral zone are involved in the biogeochemical iron cycle as the main fixation sites of iron in the system “coast–sea”. They have phytoremediation potential on the coastal territories.
Effects of Ellagotannins on Intestinal Peptidase Activity in Rainbow Trout
Authors: Mikryakov D. V. , Tarleva A. F.
Published: April 2024

The effect of ellagotannins on the activity of peptidases of the intestinal mucosa and chyme of trout was studied. Experimental groups of fish were fed with an additive based on ellagitannins (with an active substance content of 0.38, 0.76 and 1.14 g/kg of food). Sampling was carried out in 8 individuals from each group before the experiment, at 15, 30, 45 and 60 days. The study showed that ellagotannins, has a stimulating effect on the activity of peptidases. The maximum increase in the enzymatic activity in the experimental groups compared with the control group was recorded on day 45 of the experiment. A more significant increase in the activity of peptidases of the intestinal mucosa compared with chyme was established. It is concluded that ellagotannins stimulate the initial stage of cleavage of protein components of food.