bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Non-Isothermal Viscoelastic-Viscoplastic Deformation of Bending Reinforced Plates
Authors: Yankovskii A. P.
Published: April 2024

A model of non-isothermal viscoelastic-viscoplastic deformation of multidirectionally reinforced flexible plates has been developed. The viscoplastic deformation of isotropic materials of the composition is described by the relations of the flow theory with isotropic hardening, which take into account the dependences of the loading functions on temperature and strain rate intensity. The viscoelastic behavior of the composition components is described by the equations of the Maxwell–Boltzmann model. The weakened resistance of reinforced plates to transverse shifts is modeled by the Ambartsumian bending theory relations, and the geometric nonlinearity is modeled in the Karman approximation. The connection between the thermophysical and mechanical components of the problem of inelastic dynamic deformation of reinforced plates is taken into account. The temperature over the thickness of structures is approximated by a 7th order polynomial. The numerical solution of the formulated nonlinear two-dimensional problem is constructed using an explicit scheme of time steps. The viscoelastic-viscoplastic dynamic behavior of a relatively thin glass-plastic plate is studied with and without allowance for the thermal response in it. The structure is loaded transversely with an air blast wave. It is shown that the failure to take into account the thermal response in a fiberglass plate can significantly distort the calculated fields of residual deformations of the components of its composition, despite the fact that the maximum heating of such a structure does not exceed 10°C. Viscoelastic-plastic calculations, when the sensitivity of the composite materials to the rate of their deformation can be neglected, can reasonably be carried out without taking into account the thermal response of the composite plate, if there are no external heat sources of non-mechanical origin.
Nioboixiolite-(Mn2+), \(\left( {{\mathbf{N}}{{{\mathbf{b}}}_{{{2 \mathord{\left/ {\vphantom {2 3}} \right. } 3}}}}{\mathbf{Mn}}_{{{1 \mathord{\left/ {\vphantom {1 3}} \right. } 3}}}^{{{\mathbf{2}} + }}} \right){{{\mathbf{O}}}_{{\mathbf{2}}}},\) a New Ixiolite-Group Mineral from the Malkhan Pegmatite Field, Transbaikal Region, Russia
Authors: Chukanov N. V. , Pekov I. V. , Zubkova N. V. , Yapaskurt V. O. , Shelukhina Yu. S. , Britvin S. N. , Pushcharovsky D. Yu.
Published: April 2024

The new ixiolte-group mineral nioboixiolite-(Mn2+), ideally \( \left( {{\text{N}}{{{\text{b}}}_{{{2 \mathord{\left/

{\vphantom {2 3}} \right.

} 3}}}}{\text{Mn}}_{{{1 \mathord{\left/

{\vphantom {1 3}} \right.

} 3}}}^{{2 + }}} \right){{{\text{O}}}_{{\text{2}}}}{\text{,}} \) the niobian analogue of ixiolite-(Mn2+), was discovered in the Sosedka granitic pegmatite vein, Malkhan pegmatite field, Zabaikalsky Krai (Transbaikal Region), Siberia, Russia. The associated minerals are albite, quartz, microcline, elbaite, beryl, bismuthinite, euxenite-(Y), zircon, rutile, cassiterite, and cannonite. Nioboixiolite-(Mn2+) occurs as clusters of dark brown to brown-black prismatic crystals up to 0.8 × 1.5 × 5 mm embedded in albite. The lustre is submetallic to adamantine, and the streak is brown. Cleavage is not observed. The Mohs’ hardness is 4.5–5. Density calculated using the empirical formula is equal to 5.803 g cm–3. The IR spectrum and reflectance spectra in visible range are given. The chemical composition of nioboixiolite-(Mn2+) is (electron microprobe, wt%): MnO 14.94, Sc2O3 1.80, Fe2O3 0.20, Y2O3 1.34, TiO2 7.66, ZrO2 1.74, SnO2 1.01, ThO2 0.26, UO2 1.44, Nb2O5 42.80, Ta2O5 26.77, total 99.96. The empirical formula is (Nb1.59\({\text{Mn}}_{{1.04}}^{{2 + }}\)Ta0.59Ti0.47Sc0.13Zr0.07Y0.06Sn0.03U0.03\({\text{Fe}}_{{0.01}}^{{3 + }}\))Σ4.02O8 (Z = 1). The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.0474. The new mineral is isostructural to other ixiolite-group members. Nioboixiolite-(Mn2+) is orthorhombic, space group: Pbcn, a = 4.762(2) Å, b = 5.739(1) Å, c = 5.149(1) Å, V=140.7(1) Å3. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 3.662 (29) (110), 2.984 (100) (111), 2.505 (21) (021), 1.775 (21) (130), 1.748 (28) (202), 1.726 (35) (221), 1.553 (20) (113), 1.473 (19) (023), 1.463 (30) (311, 132).
Minerals of the Olivine Group from Melilite–Nepheline Paralavas of Combustion Metamorphic Complexes of Mongolia
Authors: Glushkova V. E. , Peretyazhko I. S. , Savina E. A. , Khromova Е. А.
Published: April 2024

Olivine group minerals were formed in melilite-nepheline paralavas in two combustion metamorphic (CM) complexes as result of thermal alterations of sedimentary rocks caused by multistage current and quaternary wild coal fires. Products of decomposition of the olivine solid solution into Ca-bearing fayalite and kirschsteinite have been found in paralavas of the Khamaryn–Khural–Khiid CM complex. And, besides these two minerals, forterite–fayalite, monticellite–kirschsteinite and simplectite intergrowths of kirschsteinite with nepheline were detected in paralavas of the Nyalga PM complex. Olivines are differing by their textural features, index value Mg# = Mg/(Mg + Fe) and their crystallization temperature as a consequence of local variations of formation conditions and composition of silica-undersaturated Ca-rich mafic initial melts of melilite–nepheline paralavas. Olivines of the monticellite–kirschsteinite series containing up to 86 mol. % of kirschsteinite end-member occur only in paralavas containing xenoliths of thermally modified carbonate–silicate sedimentary rocks. Crystallization of these olivines together with gehlenitic melilite took place in the process of reactionary interaction between mafic paralava melts and xenoliths of marly limestones with large variations in contents of silicate (clay–feldspar) admixture.
Bismuthite from Au–Bi and Post-Gold Sb Mineralizations within the Darasun Deposit, Eastern Transbaikalya
Authors: Spiridonov E. M. , Krivitskaya N. N. , Brysgalov I. A. , Kochetova K. N. , Korotaeva N. N.
Published: April 2024

The Late Jurassic late-orogenic volcanogenic-plutonogenic Darasun deposit of the gold-sulphide-quartz formation holds Au–Bi and post-gold Sb mineralizations. Carbonate-quartz-sulfide veins in Western part of the deposit are surrounded by listvenite rims. Their golden ores were formed under conditions of low activity of S2, they contain pyrrhotine, arsenopyrite, chalcopyrite, pyrite, bismuthate I (Bi1.89–1.98Sb0.11–0.02)2S3, galenobismuthite, nests of bismuth and ikunolite Bi4S3. There is observed exsolution of ikunolite mainly into the native bismuth (Bi0.98–1Sb0.02–0) and bismuthite-II; the composition of bismuthite-II in center of aggregates with the bismuth is (Bi1.96–1.97Sb0.04–0.03)2S3, whereas the composition on their periphery is an more antimonian one is (Bi1.91–1.92Sb0.09–0.08)2S3. While the high fineness gold (970–935 ‰) arose there by the action of gold-bearing hydrothermal solutions, the native bismuth has been partly replaced with maldonite. Jonassonite and Pb–Bi sulphosaults (mainly, cosalite Pb2Bi2S5) were formed later in these ores. The overlaying Sb mineralization has given formation not of antimonite (stibnite), but of Pb–Sb sulphosaults (moeloite Pb6Sb6S15, etc.), pseudomorphs of chalcostibite after chalcopyrite, as well as aurostibite AuSb2 after minerals of gold. The replacement of maldonite by aurostibite was resulted in appearance of bismuthate III. The probable replacement reaction is: 2Au2Bi + 6Sb solv. + + 3Sb2S3 solv. → 4AuSb2 + Bi2S3. Bismuthite III (Bi1.72–1.96Sb0.29–0.94)2(S2.98–3Se0–0.02)3, containing 1–7 wt % of Sb, is a product of the maldonite replacement by aurostibite. Moeloite and stibian bismuthate III arose by the Sb mineralization overlaying ores with cosalite. The probable replacement reaction is: 3Pb2Bi2S5 + 3Sb2S3 solv. → Pb6Sb6S15 + 3Bi2S3. Stibian bismuthite-III contains 4–17 wt % of Sb in its composition (Bi1.36–1.71Sb0.64–0.29)2S3. Appearance of bismuthite with the Sb mineralization where it was developed over ores with native bismuth, maldonite and Pb–Bi sulphosaults is the evidence of key role of the mass action law in mineral-forming processes.
Mineralogy of Clinozoisite Amphibolites in the Khitoostrov Occurrence of Corundum-Bearing Rocks (Fenno-Scandinavian Shield)
Authors: Akimova E. Yu. , Skublov S. G.
Published: April 2024

A study of composition of minerals (major and rare-earth elements) of clinozoisite amphibolites closely associated with corundum-bearing rocks at the Khitoostrov occurrence (North Karelia) was carried out. The clinozoisite amphibolites contain ferruginous phlogopite containing more Al than the ferruginous phlogopite in the host garnet amphibolites; calcium amphibole belongs to the chermakite–pargasite–sadanagaite series; the basic plagioclase which is absent in the host rocks, and margarite. Reactionary relationships of minerals are noted – plagioclase-amphibole symplectites around garnet porphyroblasts, development of clinozoisite after calcium amphibole. Some of the minerals (clinozoisite, calcium amphibole) acquire rare-earth elements (REE) distribution spectra that are uncharacteristic for them, inheriting them from substitutable minerals in the areas of distribution of reaction structures: calcium amphibole inherits the spectrum of garnets, and clinozoisite inherits the spectrum of calcium amphibole. The hypothesis of metasomatic origin of clinozoisite amphibolites and the redistribution of REE under the influence of fluid are discussed.
Winners of the Nomination “Mineral of the Year” (Period 2014–2021): Contribution into Mineralogical Crystallography
Authors: Pushcharovsky D. Yu.
Published: April 2024

The principal specific features are considered for new minerals discovered during the period 2014–2021 and nominated as winners of their competition “Mineral of the Year” announced by the IMA in 2014. The corresponding publications contain the detailed description of phenomena complicating the real structure (merelaniite), the uncommon combination of chemical elements (seaborgite), fragments of compounds previously known only in synthetic nonorganic phases (ophirite, chanabayaite, bojarite). The special attention is focused upon the indicative role of these minerals for reconstruction of physical-chemical conditions accompanying their crystallization, as well as to their position in corresponding transformational-genetic series. There is proposed the crystal growth model of the new W-bearing mineral tewite, which has been proved experimentally.
Synthesis of Zirconosilicates under High-Alkaline Conditions
Authors: Kovalskaya T. N. , Ermolaeva V. N. , Chukanov N. V. , Kovalskiy G. A. , Varlamov D. A. , Chaychuk K. D.
Published: April 2024

Synthesis of zirconosilicates from a stoichiometric mixture of Na2CO3, CaO, Fe2O3, ZrOCl2, and SiO2 with the Na : Ca : Fe : Zr : Si ratio belonging to the compositional area of eudialyte-geoup minerals (EGM), was carried out under high-alkaline conditions (in the presence of 1 M aqueous solutions of NaCl and 46% NaOH) at a temperature of 600 °C and a pressure of 2 kbar, for 10 days. In some experiments, natural raslakite (a Ca-deficient EGM) was used as a seed added in amount of 2 wt % of the whole charge. According to electron microprobe analyses, powder X-ray diffraction data and IR spectroscopy, high-alkaline EGM, zirsinalite, parakeldyshite, and aegirine were identified in the products of the syntheses carried out using a charge with relatively high Si : Zr, Fe : Zr and Na : Zr ratios. At relatively low values of these ratios, no EGM formed.
Crandallite and Florensite-(Ce) from a Quartz Vein of the Area Zhelannoye Deposit (Subpolar Ural)
Authors: Repina S. A.
Published: April 2024

The article displays data on minerals of the plumbogummite group – crandallite and florencite-(Ce). Minerals were found on a fragment of a hematite aggregate recovered from the lower pinch out of a quartz vein of the Zone 25 occurrence. It is situated in close neighborhood to the known Zhelannoye deposit of vein quartz and rock crystals and the Au-Pd-REE ore deposit Chudnoye. Crandallite segregations are represented by two forms: rhombohedral crystals and spherulites. There are distinguished three generations of crandallite: the first one represented by rhombohedral crystals, the second – by crusts on the rhombohedron faces, the third – crandallite spherulites on the surface of rhombohedrons. The crusts, 150 µm thick, consist of four layers: REE-bearing crandallite, symplectite intergrowths of crandallite with florensite-(Ce), spherulites, and powdering of crandallite crystals. The first and second generations of the mineral were crystallized from solutions, the third resulted the redeposition. There are varying contents of Sr, Ba, REE, U, Fe, S, and Si admixtures in crandallite of different types.
Geomorphometric Methods Application for Lake Ladoga Bottom Morphology Investigation
Authors: Aksenov A. O.
Published: April 2024

Abstract—In present research results of Lake Ladoga bottom morphology analysis are presented. Semi-automated instrumental classification of digital bathymetric model with application of geomorphometric parameters was executed to achieve the goal. Bathymetric position index and slope were used as classifiers. As a result, 8 types of surfaces were distinguished, which were mapped on the morphological scheme. Plains, slopes and linear top (ridges, heights) and bottom (hollows, depressions) were distinguished. Combinations of such elements allow to contour 3 zones which correlate to morphostructural areas: South-Ladoga, Central-Ladoga, North-Ladoga. Differences of these zones depend on both lake’s basin geological structure and exogenous factors of Late-Pleistocene-Holocene (glacial, glacial lacustrine processes). The suggested approach proves high efficiency for Lake Ladoga greatly variable morphology study.
In-stream Mining in Alluvial River Channels: Response, Consequences and Perspectives
Authors: Berkovich K. M. , Zlotina L. V. , Turykin L. A.
Published: April 2024

Abstract—On the basis of long-term field and analytical research, the response of the channels of different rivers to one of the types of mechanical impact on rivers – the in-stream mining – is considered. The nature and rates of the response of the river channels of free-flowing and regulated rivers to the in-stream mining, disturbance extent of the channel morphology and the rivers hydrological regime are revealed. The purpose of the work is to assess the possibilities of in-stream mining and allowable mine’s sizes which bases on the general principles of the theory of fluvial processes, and to minimize the negative effects of given mechanical disturbances on rivers and floodplains
Small and Medium-Sized Lakes: Characteristics of their Functioning at Present and Methodological Issues of their Recreational Potential Assessment (on the Example of Lakes on the Territory of the Republic of Bashkortostan)
Authors: Gareev A. M. , Sayfullina E. N. , Galeeva E. M.
Published: April 2024

Abstract—The article reveals the main characteristics of the functioning of small and medium-sized lakes at present under the influence of a set of natural and anthropogenic factors, as well as methodological provisions for assessing their recreational potential. It is shown that the most significant negative changes in them occur especially in those regions which are characterised by high scales of influence of economic activity confined on their catchments. The main factors influencing the level of eutrophication of lakes and, consequently, their use for recreation purposes include such factors as the removal of dissolved and undissolved substances from catchments into water bodies themselves, siltation, changes in morphometric characteristics and reduction in the intensity of external water exchange. In order to justify the optimal parameters of recreational loads on the studied water bodies, the analysis of currently used methodological approaches was carried out, their advantages and disadvantages were revealed, which allowed to justify new approaches to the assessment of recreational potential of water bodies.
Regional Dynamics of Industry, Agriculture and Population in Russia in 1990–2020: Geoecological Interpretation
Authors: Klyuev N. N.
Published: April 2024

Abstract—The grouping of Russian regions by the type of conjugate dynamics of industry, agriculture and population for 1990–2020, indirectly reflecting the dynamics of the integral anthropogenic load on nature, is carried out. The zones most severely affected by the transformational depression have been identified, which cover practically the entire European Non-Chernozem region, south of Eastern Siberia and the Far East. And a significant increase in loads is observed in the North Caucasus, the Russian Baltic States, the sub-latitude area of the regions stretching from the Bryansk region to Bashkortostan, as well as the Tyumen region. The increase in load occurred primarily within the steppe and forest-steppe zones, which were most transformed by anthropogenic activity. In general, “pressure” on nature increases in a well-developed territory (about 1/10 of the country, where about a third of the population lives), and decreases in a vast poorly developed territory (about half of the territory and 1/6 of the population of Russia). A new environmentally unfavorable trend in the dynamics of pressures on nature is their relative shift to coastal regions, to vulnerable to impacts and scarce in the country recreationally attractive coasts of the Atlantic seas, as well as the Caspian Sea-lake. It has been established that the increase in all types of loads in the leading regions is much more significant than their reduction in the regions of maximum decline. Therefore, the deterioration of the environmental situation in the regions of strong growth in loads is more likely than its improvement in the regions leading their decline. The increase in the load occurred primarily within the steppe and forest-steppe zones, most transformed by anthropogenic activity. In general, the “pressure” on nature increases in a well-developed area (about 1/10 of the country, where about a third of the population lives), and decreases in a vast underdeveloped area (about half of the territory and 1/6 of the population of Russia). A new environmentally unfavorable trend in the dynamics of loads on nature is their relative shift to the coastal regions, to the recreationally attractive coasts of the Atlantic seas, as well as the Caspian Sea–lakes, vulnerable to impacts and scarce in the country. It has been established that the increase in all types of loads in the leading regions is much more significant than their reduction in the regions of maximum recession. Therefore, the deterioration of the environmental situation in the regions of a strong increase in loads is more likely than its improvement in the regions-leaders of their decline.
Numerical Investigation of the Structure of Fracture Network Impact on the Fluid Flow through a Poroelastic Medium
Authors: Legostaev D. Yu. , Rodionov S. P.
Published: April 2024

Two-dimensional single-phase flow of a weakly compressible fluid through a deformable fractured-porous medium is considered. A poroelastic model is used for coupled simulation of the fluid flow and the related changes in the stress state of the medium. Fracture network is simulated using the discrete fracture model. The fractures in the region under consideration have random location and orientations, and the fracture length distribution follows a power law. The dependence of the hydraulic properties of fractured porous media on its stress-strain state and the structure of the fracture network is studied. Numerical study was performed for various realizations of fracture network obtained using multiple random generation. It is found that the permeability of the fractured porous medium is determined mainly by the structure of the fracture system characterized by the percolation parameter. According to the simulations results, hydraulic properties are significantly affected by the stress-strain state only for connected fracture systems. An approximation is proposed to define the dependence of the equivalent permeability of a fractured-porous medium on the following parameters: the connectivity of the fracture system, the stress-strain state of the medium, and fracture properties such as stiffness and aperture.
Generation of a Vertical Fine Structure by Internal Waves on the Sea Shelf
Authors: Slepyshev A. A.
Published: April 2024

Free internal waves are considered in the Boussinesq approximation with account of horizontal turbulent viscosity and diffusion in a two-dimensional flow in the sea of constant depth. In the linear approximation the boundary-value problem for the amplitude of vertical velocity has complex coefficients and is solved numerically using the third-order implicit Adams method. The vertical component of the Stokes drift velocity and the vertical wave fluxes of mass and salt are found in the second order in the wave amplitude. These fluxes lead to generation of a vertical fine structure that has an irreversible nature.
Analysis of Self-Oscillation Processes in a Cavity with a Flow of OpenType on the Basis of the Data of Vortex-Resolving Calculations
Authors: Dan’kov B. N. , Duben’ A. P. , Kozubskaya T. K.
Published: April 2024

The mechanisms of self-oscillation processes occurring in cavities of open flow type are considered and substantiated on the basis of a detailed investigation of the phenomena of hydrodynamic, flow-rate, wave, and resonance nature. The theoretical conclusions are substantiated by an analysis of the data of numerical experiments performed by different authors.
Influence of the Initial Shape of a Bubble on Bubble Rise Dynamics in a Stagnant Viscous Fluid
Authors: Morenko I. V.
Published: April 2024

The effect of the shape of a single bubble at the initial instant on the bubble rising dynamics in a viscous fluid at rest is studied. Elliptical bubbles with various compression ratios are considered. Mathematical simulation of the process is based on the volume of fluid method, which makes it possible to trace the evolution of the interface. The results of calculations of test problems are in adequate agreement with the data of other authors available in the literature. The shapes of the interfacial surface and the velocity and vorticity fields in the process of bubbles rising in the gravity field are obtained at the Reynolds number Re = 35 and the Bond numbers Bo = 10 and 125. The main attention is paid to the regime of unsteady motion. It is shown that the bubble rise velocity has one or two local maxima depending on the properties of the media. It is found that bubbles initially elongated vertically rise more rapidly than those elongated horizontally.
Distinctive Features of Plume Formation on Collision of Two Laminar Gas Jets
Authors: Kozlov V. V. , Litvinenko Yu. A. , Katasonov M. M. , Sarychev D. V. , Shmakov A. G.
Published: April 2024

The results of an investigation of the interaction between two colliding axisymmetric laminar microjets of propane-butane mixture with and without diffusion combustion are presented. The gas mixture components flow out through round tubes at the same velocities. In the course of the experiments the lateral position of the tubes with respect to each other was varied with conservation of the angle between them. The distinctive features of the resulting jet formation are established as functions of the transverse position of the tubes. If the tubes lie in the same plane, then the resulting jet is formed in the plane orthogonal to them. This process can be observable in the case of the interaction between the jets both with and without flame. With increase in the jet outflow velocity a region of local discontinuity of the flame front is found to exist.
Experimental Investigation of the Structure of Disturbances from Two Pulsed Sources in the Flat-Plate Supersonic Boundary Layer
Authors: Afanasev L. V. , Yermolaev Yu. G. , Kosinov A. D. , Kocharin V. L. , Semionov N. V. , Yatskikh A. A.
Published: April 2024

The work is devoted to the development of a new experimental method for entering controlled disturbances with a given frequency-wave structure into a supersonic boundary layer. Experimental data on the formation of disturbances from two pulsed sources (pulsed glow discharge) in the laminar flat-plate boundary layer at the Mach number equal to 2 are given. The experiments were carried out in the T-325 wind tunnel of ITAM SB RAS. The localized sources were spaced out at the same distance from the leading edge of the plate at 6 mm from each other spanwise. Flow pulsations were measured using a hot-wire probe of constant temperature anemometer, the signal was recorded synchronously with ignition of the discharges. This made it possible to distinguish the pulsations from the discharges against the background of random uncontrolled “natural” pulsations of the boundary layer. The spatial-temporal and frequency-wave structure of the generated disturbances from a single or two discharges, operating synchronously or with a time delay, are analyzed. It is found that the maximum difference in the structure of disturbances from one and two sources is observed in the central region, while at the side boundaries of the disturbances, the pulsations are close in all considered cases. In the wave spectra of disturbances from two discharges, nodes and antinodes are formed. Their position is determined by the distance between the sources and the time delay in their operation.
Regimes of Fluid Displacement from an Anisotropic Formation in the Gravity Field
Authors: Chernova A. A. , Afanasyev A. A.
Published: April 2024

The problem of two-phase flow of incompressible fluids through anisotropic porous media in the gravity field is considered. Similarity criteria characterizing the flow directions of the displacing and displaced fluids are determined. The regimes of displacement from an anisotropic formation are classified within the framework of study of numerical solutions to the profile problem of flow through an anisotropic porous medium. It is shown that there are four regimes corresponding to qualitatively different flows. Their effectiveness is compared in terms of the coefficient of fluid extraction from the formation and the displacement sweep factor. The influence of the capillary pressure on the displacement efficiency in various flow regimes is studied. It is shown that in some cases increase in the influence of the capillary pressure leads to increase in the displacement coefficient, while in other regimes, on the contrary, to its decrease.
Impact of a water microjet on a microfiber
Authors: Bazilevskii A. V. , Rozhkov A. N.
Published: April 2024

The transverse impact of an impulsive water microjet on single cylindrical fibers is investigated. The stages of ejection, breakup, and collision of the microjet were recorded using high-speed photography methods. Significant slowing down of the microjet by the fiber and splitting into two parts were detected. The mechanisms of the observed phenomena and the influence of various factors are discussed.
Trajectories of Liquid Particles in a Dark Soliton Field in a Fluid Beneath an Ice Cover
Authors: Ilichev A. T. , Savin A. S. , Shashkov A. Yu.
Published: April 2024

A fluid layer of finite depth described by Euler equations is considered. The ice cover is modeled by a geometrically non-linear elastic Kirchhoff–Love plate. The trajectories of liquid particles under the ice cover are found in the field of a nonlinear surface traveling wave tending to a periodic wave at infinity: the so-called “dark soliton” (which is a nonlinear product of a step-wave and a periodic wave) of small but finite amplitude. The presence of dark solitons in the system is an indicator of the modulation stability of the carrier periodic wave (defocusing). The analysis uses explicit asymptotic expressions for solutions describing wave structures on the water–ice interface such as dark solitons, as well as asymptotic solutions for the velocity field in the liquid column generated by these waves.
Supersonic Flow past a Sharp Plate with Surface Anomalous Glow Discharge in a Magnetic Field
Authors: Surzhikov S. T.
Published: April 2024

The electrodynamic structure of an anomalous glow discharge between two plane electrodes located on the surface of a sharp plate in supersonic flow of molecular nitrogen is studied numerically in a wide range of Mach numbers using a modified ambipolar model of quasi-neutral electric-discharge plasma. The ambipolar diffusion coefficient and the effective ionization rate are modified while taking into account the external magnetic field. The problem is solved in the two-dimensional x–y formulation, when the external magnetic field strength is directed in the positive or negative direction of the z axis. The parameters of anomalous glow discharge are numerically studied in the pressure range p = 0.14–5 Torr and the voltage drops on the quasineutral current column of discharge plasma V = 30–320 V. The main problem parameters which make it possible to obtain a reasonable agreement with the available experimental data are determined.
Effect of pH on Cytomorphological Parameters of Erythrocytes of the Rana macrocnemis Tadpoles
Authors: Gamidova D. M. , Rabadanova A. I.
Published: April 2024

The article presents the results of studies of the effect of acidic (4.0, 5.0) and alkaline (9.0) pH values on cytomorphological parameters of erythrocytes of Rana macrocnemis tadpoles. The negative effect of pH 4.0 on the cytomorphological features of erythrocytes is shown, expressed in a decrease in their geometric parameters (area, volume), which leads to a deterioration of their function. Changes in the linear and geometric parameters of tadpole blood cells when exposed to pH 5.0 and 9.0 in both series of the experiment allow us to judge their focus on improving the efficiency of oxygen transport, that is, they are compensatory in nature.
An in vitro Arabidopsis thaliana Root Structural and Functional Characterization
Authors: Bulavin I. V. , Sidyakin A. I.
Published: April 2024

Two models of Arabidopsis thaliana rhizogenesis in vitro were studied: 1) from callus and 2) leaf explants petioles on the Murashige and Skoog one-tenth strength hormone-free nutrient medium and also with the addition of the growth regulator such as indole-3-butyric acid. Morphological and anatomical studies show significant changes in the structure of the roots formed de novo in vitro from callus tissue, while the organs from leaf explant petioles were similar to those formed from the seed (primary). By Sabinin-Kolosov method, a decrease in the percentage of active root surface was established. Occurrence of the structural changes during in vitro rhizogenesis and their effect on root functionality are discussed.
The Evolution of Redfishes of the Genus Sebastes (Perciformes: Sebastidae) of the Atlantic and the Arctic Oceans: Budding Speciation in the Species Flock
Authors: Rolskii A. Y. , Artamonova V. S. , Makhrov A. A.
Published: April 2024

The evolutionary history of North Atlantic Sebastes redfishes was reconstructed as a result of studying the mitochondrial DNA D-loop sequences of Sebastes redfishes inhabiting the North Atlantic and the Arctic Oceans. It was shown, that speciation of these redfishes occurred in several stages. During the first stage, the ancestor of Norway redfish (S. viviparus) diverged from the common ancestor species in the process of allopatric speciation. Ancestor of Acadian redfish (S. fasciatus) diverged from the common ancestor as it evolved. Budding speciation in the species that would later evolve into golden redfish (S. norvegicus) resulted in emergence of beaked redfish (S. mentella). Paleoclimatic events seem to have played the key role in species divergence as they caused habitat fragmentation allowing the isolated groups to become genetically distinct in the meantime. The conducted analysis of Sebastes redfishes speciation brings into question the generality of widely accepted views on fish sympatric speciation. It also serves as an argument against the molecular clock hypothesis.
Parameters of Lipid Metabolism in Underyearlings of Atlantic Salmon Salmo salar Reared under Different Regimes of Photoperiod and Feeding Modes in Aquaculture in the Sourthern Region of Russia
Authors: Murzina S. A. , Provotorov D. S. , Voronin V. P. , Kuznetsova M. V. , Kuritsyn A. E. , Nemova N. N.
Published: April 2024

A comparative study of the lipid and fatty acid composition of Atlantic salmon underyearlings reared under natural and continuous light in commercial aquaculture in the summer-autumn period in North Ossetia-Alania was carried out. A stable change in the main indicators of lipid metabolism in salmon underyearlings from September to November was found, aimed at preparing juveniles for smoltification. A change in key fatty acid indicators was detected: an increase in the content of PUFAs due to (n-3) PUFAs, and the “marine” type of PUFA – 22:6 (n-3), high values of the ratios (n-3)(n-6) PUFA, 18:3(n-3)/18:2 (n-6), 22:6(n-3)/ 18:3(n-3). It has been shown the stimulating effect of the combined and stable action of the continuous photoperiod and feeding in the summer-autumn period on the preparation for smoltification of Atlantic salmon fingerlings grown under aquaculture conditions.
Coexistence of the Water Shrew (Neomys fodiens) and the Common Shrew (Sorex araneus), the Competing Species, in a Flucturing Environment: Sociability and Space Use in a “Dry” Habitat
Authors: Shchipanov N. A. , Kasatkin M. V.
Published: April 2024

Sustainable (no trend in the abundance of interacting species) coexistence of species can be maintained due to fluctuations in their abundance and distribution over habitats in a heterogeneous environment. In the water shrew and the common shrew, joint settlements exist in near-water areas and occasionally appear in “dry” habitats, where the water shrew periodically invades. Given the well-known overlapping food niches of these species, one would expect the discovery of mechanisms that reduce competition, however, in “dry” habitats, we did not find such mechanisms. The use of space is characterized by a random overlapping of the home ranges of animals. In the preference test (a container with an animal versus an empty container), individual repeatability of sociability was found in tests with a conspecific stimulator, but was absent in tests with a stimulant of another species. The presence of the water shrew (as a stimulant) in the behavioral test did not increase of anxiety of common shrews, but increased the thoroughness of exploration. The reaction of the water shrew to the common shrew was not found in interspecific tests. In the absence of specific adaptations aimed at the spatial segregation of animals, the coexistence of the water shrew and the common shrew is quite well explained by “fluctuation-dependent” models of coexistence.
Regulation of the Activity of Decarboxylating Malate Dehydrogenases in Corn Leaves during an Adaptive Response to Salt Stress
Authors: Epintsev A. T. , Gataullina M. O.
Published: April 2024

The effect of salt stress on the activity of decarboxylating malate dehydrogenases in maize leaves during the adaptive response of cellular metabolism to salt stress was studied. It was shown that excess NaCl concentrations cause an increase in the enzymatic activity of both NAD+-ME and NADP+-ME. The greatest contribution to the increase in the activity of NAD+-ME is made by the intensification of the expression of the nad-me2 gene. At the same time, the expression of nad-me1 under salinity increases to a lesser extent. Methyl-specific PCR showed an inverse relationship between the expression of nad-me2 and the degree of methylation of the promoter of this gene, while nad-me1 and nadf-me, apparently, are regulated by different mechanisms. A different functional role of each isoform of the studied malic enzymes in the adaptive response of cellular metabolism is assumed.
Genetic Divergence of Closely Related Species Oxytropis strobilacea, Oxytropis adamsiana and Oxytropis vassilczenkoi (Series Strobilacei of the Section Orobia Fabaceae) from Asian Russia
Authors: Kholina A. B. , Artyukova E. V. , Yakubov V. V. , Khoreva M. G. , Mochalova O. A. , Sandanov D. V. , Selyutina I. Yu.
Published: April 2024

The genetic diversity and divergence of closely related species Oxytropis strobilacea, O. adamsiana, and O. vassilczenkoi series Strobilacei of the section Orobia (Fabaceae) from Asian Russia were studied using the data of nucleotide polymorphism of the psbA–trnH, trnL–trnF, and trnS–trnG intergenic spacers of cpDNA, as well as the ITS nrDNA. Most populations are characterized by an average and high level of chloroplast genetic diversity (h varies from 0.600 to 1.000). 65 chlorotypes were identified, no shared chlorotypes were found in taxa, and that confirms the status of O. vassilczenkoi as a separate species. Two phyletic lineages were found for O. strobilacea that indicates an intensively proceeding diversification process. Among the seven identified ITS ribotypes, one ribotype was shared for all three species, probably, due to their common origin and relatively recent divergence.
Peculiarities of Dynamics and Structure of Communities of Small Mammals at High Latitudes
Authors: Volpert Ya. L. , Shadrina E. G.
Published: April 2024

The studies of communities of small mammals were conducted in Yakutia from 1979 to 2017. It was established that communities of small mammals of the northern sparse forest and especially forest-tundra, where community members are at the limit of their ecological tolerance, have a number of features. Against the background of a decrease in species richness, there is an increasing tendency to monodominance, with periodically alternating dominant species, which, in our opinion, is evidence of adaptations that, to a certain extent, ensure the sustainability of communities.
Dynamics of Phytomass Spatial Organization in a Reserved Steppe Landscape: Case Study of Burtynskaya Steppe, Orenburg Reserve
Authors: Khoroshev A. V. , Ashikhmin A. P.
Published: April 2024

The “hot spot analysis” was applied to materials from 51 Landsat satellite images using the example of the “Burtinskaya Steppe” area of the Orenburgsky Nature Reserve, to study the dynamics of areas of positive phytomass anomalies relative to a neighborhood with a radius of 300 m. The purpose of the study was to establish the dependence of the variability of areas of increased phytomass on the landscape structure and hydrothermal conditions. We concluded that the switching of phytocenoses in transition zones from steppe to meadow type of functioning is ensured by varying the ratio of xerophytes and mesophytes depending on fluctuations in hydrothermal conditions. The frequency and area of positive phytomass anomalies in the bottoms of gullies correlates with their area on partially forested slopes, which indicates the positive role of forest vegetation in the stabilization of moisture influx into the bottoms. In deforested catchment areas of the south-facing slopes, the area of positive phytomass anomalies is determined by the supply of snow moisture, and in the catchment areas of north-facing slopes, by warm-period precipitation. The binding factors for the most stable positive anomalies of phytomass are the moisture convergence and the landform concavity rather than the catchment area.
Genetic and Morphological Variability of the Small Wood Muse (Apodemus (Sylvaemus) uralensis, Rodentia) in the North Caucasus
Authors: Tembotova F. A. , Puzachenko A. Yu. , Amshokova A. Kh. , Kononenko E. P. , Emkuzheva M. M.
Published: April 2024

The genetic and morphological variability of the southern form of the European chromosomal race of the small wood mouse Apodemus (Sylvaemus) uralensis (Pallas, 1811) in the North Caucasus was studied. The results of the sequence analysis of the cytochrome b gene fragment from 9 geographical samples from the western, central and eastern parts of the North Caucasus indicate a low degree of their genetic isolation with a relatively high diversity of haplotypes. Analysis of morphological variability revealed high variety: three morphological groups were identified. Representatives of all three or two groups were found in the same geographical samples, but their distribution did not conform to the hypothesis of random occurrence. Based on indirect evidence, hypotheses about possible causes of the observed features of regional small forest mouse biodiversity are formulated, which require verification in the course of future studies. In particular, we hypothesised that in the Late Pleistocene (130–11.7 thousand cal yr BP) there were several isolated populations in the region that could have been sources of species diversity in the Holocene.
The Intra-Annual Variability of Immune System Organs and Lysozyme Content in Male Pike Esox lucius L.
Authors: Subbotkin M. F. , Subbotkina T. A.
Published: April 2024

The effect of the physiological state on the lysozyme concentration in the liver, kidney, spleen and serum, as well as the total amount of the enzyme in the organs, was studied in male pike Esox lucius L., 1758 under different conditions of the annual cycle. Multidirectional intra-annual dynamics of organ somatic indices and quantitative parameters of lysozyme in fish tissues and organs, depending on the temperature regime of the water body, was found. Despite significant changes in liver size and lysozyme concentration, the total amount of the enzyme in the organ, the lysozymic index, remained constant. A similar result was found in the spleen. When the influence of the temperature factor at low temperatures was minimized, the liver parameters changed to the opposite ones, while those in the kidney remained unchanged. Such a temperature regime did not affect the spleen parameters and the concentration of the enzyme in the serum. With significant differences between the liver and spleen in the enzyme concentration and size, their lysozymic indices were indicators of the same level. Stages of gonad maturity affected the liver index and the amount of lysozyme in the kidney, but the correlation of the kidney enzyme with maturity was not significant. The kidney lysozyme and the spleen parameters correlated with body mass without organs, although fish weight and length were not influencing factors. The size of the kidney, unlike the spleen, did not affect the enzyme in fish tissues. The liver and kidney enzyme concentrations and kidney lysozymic index were inversely correlated with liver size. A complex nature of the enzyme relationships in organs was revealed, at which the amount of lysozyme in one organ could affect the amount of the enzyme in the other. The relationship between the concentration of serum lysozyme and the morphophysiological parameters of fish under stable low temperature conditions in the water body was not found.
Morphological and Anatomical Features of Plantago maritima L. As an Adaptive Reaction to the Conditions of Coastal Biotopes
Authors: Sonina A. V. , Dyachkova T. Yu. , Morozova K. V.
Published: April 2024

The morphological and anatomical parameters of the vegetative and generative organs of plants Plantago maritima L. were studied in different biotopes of the littoral zone on the coast of the White Sea in the vicinity of the village Rastnavolok (Belomorsky district, Republic of Karelia). It has been established that plants have developed certain adaptations to conditions of the littoral zone: two biomorphs are formed (rosette and upper rosette with elongated upper internodes) as an adaptation to covering with soil during tides and storms. Within the littoral zone under different flooding conditions, plants differ in some anatomical features. The thickness of the water-strage parenchyma correlates directly with the thickness of the leaf, it varies within the littoral zone depending on the time the plants are flooded with salt water. Well-developed integumentary and mechanical tissues of the root and rosette shoots are an adaptive response to the mobility of the soil substrate and water mass during tidal surges. The development of aerenchyma in underground vegetative organs ensures gas exchange under flooding conditions. Significant differences of the studied anatomical and morphological parameters in biotopes of the littoral showed the wide adaptive capabilities of P. maritima, which ensure its dominance in the plant communities of the White Sea coast.
The Evolution of Cities and Their Functional Diversity
Authors: Baburin V. L.
Published: April 2024

The article deals with the problems of the relationship between the agglomeration effects of localization and urbanization. As an indicator of these processes, the relationship between the population of cities and the number of enterprises and organizations in them is used. It is assumed that the number of enterprises indirectly reflects the diversity of places of employment, although not weighted by industry structure. As a result of the study, a statistically significant relationship between these two indicators was established both for the subjects of the federation and for cities with a population of more than 100 thousand people. The main focus is on the study and explanation of deviations from the general pattern of the rank of the city/the number of enterprises in it. On this basis, the typology of cities is carried out on several grounds: administrative status, economic and geographical location, the presence of large city-forming enterprises. According to the results of the study, specific parametric characteristics were identified that allow us to distinguish single-industry cities. Using the example of the key, the study was continued for settlements with less population, as a result, it was found that for them, geographical location and specialization are more important than population.
Granulometric Composition of Abrasion-Accumulative Jumpers of Volgograd Reservoir Bays as an Indicator of Sediment-Forming Currents’ Speeds
Authors: Baranova M. S. , Filippov O. V. , Bryzgalina E. S. , Kochetkova A. I.
Published: April 2024

Separation of bays from the main water area of Volgograd Reservoir by abrasion-accumulative jumpers is one of the regional problems now. This process arises due to alongshore sediment transport. Granulometric composition describes the movement of sediments of abrasion-accumulative jumpers under the influence of alongshore currents. We determined granulometric parameters of jumpers, and we made evaluative calculation of sediment-forming currents’ speeds based on materials of 2019–2020. We studied 82 samples from 24 right-coast and left-coast bays. Field (sediment sampling, visual characteristic of the coast’s lithological composition) and analytical (granulometric analysis, graphic and mathematical methods) research methods were applied. We have established that size of sediments participating in the construction of abrasion-accumulative jumpers is from 100–50 mm (coarse pebble) to 0.05 mm or less (small dusty particles). All studied particles turned out to be rounded or well rounded. This gives grounds to classify them as sediments. There are differences in the granulometric composition of jumpers’ sediments on the right and left coasts of the Reservoir. Coarse pebble (100–50 mm) and medium pebble (50–20 mm) or medium sand (0.5–0.2 mm) and fine sand (0.2–0.1 mm) dominates in sediments’ composition of right-coast bays jumpers. Medium sand (0.5–0.2 mm) prevails in sediments’ composition of left-coast bays jumpers. Here was registered size of sediment particles less than 0.05 mm. The currents’ speeds forming abrasion-accumulative jumpers are from 0.47 to 3.45 m/s in the right coast and from 0.47 to 1.63 m/s in the left coast. Sediment samples of estuarine jumpers have different degree of sorting (1.13–14.40). This attests about differences in currents’ speeds forming these landforms in different time periods. The granulometric composition of sediments is an indirect sign of the dynamics of already formed jumpers. It is an indicator of sediment-forming currents’ speeds. Sedimentation of sediments in the Volgograd Reservoir occurs at a close distance from the source of their income.