bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Mechanical Concept of Self-Assembly of Nanomaterials
Authors: Babeshko V. A. , Evdokimova O. V. , Babeshko O. M. , Evdokimov V. S.
Published: April 2024

The article presents the mechanical concept of self-assembly of nanoparticles. It is assumed that nanoparticles are deformable stamps in a plane dynamic contact problem, lying on the boundary of a multilayer deformable medium. The constant vibration in the microcosm is caused by the oscillatory mode by the energy of phonons and magnons. Earlier, in the works of the authors, the mechanical concept of self-organization of nanoparticles was presented. It is based on high-frequency resonance, which causes the formation of standing waves. They localize the available aggregates of nanoparticles on the crest of standing waves. The self-assembly of nanoparticles is based on resonance, previously predicted by Academician I. I. Vorovich and inherent only in deformable dies in contact problems on a multilayer medium. Deformable nanoparticles are modeled by fractals representing packed block elements described by the Helmholtz equation. The resonance of the deformable dies allows the capture of nanoparticles, dictated by the Coulomb forces of attraction. It is shown that the combination of two fractals generates a new fractal with a combined carrier, and in the case of multiple association, a fragment of a nanomaterial is obtained. To implement the study, for the first time it was possible to construct a high-precision approximate solution of a plane contact problem on the action of a stamp of any finite size on a multilayer base. This result is dictated by the need for an analytical construction of the theory of self-assembly of nanomaterials.
Stability of Stationary Motions of Mechanical Systems with a Particular Goryachev-Chaplygin Integral
Authors: Novikov M. A.
Published: April 2024

In the existing studies, the stationary motions in a mechanical system in the case of the existence of a partial Goryachev-Chaplygin integral are analyzed. Some invariant sets and their stability, including one of the stationary motions, are also studied. In this article, the stability of the remaining second rest state is finally investigated.
Mechanical System Showing "Catastrophic Behavior"
Authors: Moshinskii A. I.
Published: April 2024

The behavior of a mechanical system when the parameters characterizing it change is investigated. The analysis shows that stepwise changes (catastrophes) occur in the system in a certain area of control parameters. The considered problem admits an exact (global) analysis of the catastrophe, without involving various expansions and assumptions. The proposed mechanical design can serve to demonstrate the occurrence of a catastrophe.
Townendite, Na8ZrSi6O18, an Indicator of Extremely High Agpaicity and Important Concentrator of Zirconium in Peralkaline Rocks of the Lovozero Pluton, Kola Peninsula
Authors: Pekov I. V. , Zolotarev A. A. , Chukanov N. V. , Yapaskurt V. O. , Turchkova A. G.
Published: April 2024

Townendite, ideally Na8ZrSi6O18, earlier considered as an extremely rare mineral, is found in large amount in a hyperagpaitic pegmatoid aegirine-nepheline-sodalite-microcline rock with eudialyte, kazakovite, villiaumite, lomonosovite and alkali sulfides in deep levels at Mt. Kar-nasurt, Lovozero alkaline pluton, Kola peninsula, Russia. Townendite forms transparent lilac to light violet segregations up to 6 × 4 cm. Its crystal structure was studied on single-crystal XRD data, R1 = 2.29%. The mineral is trigonal, R-3m, a = 10.2910(3), c = 13.1577(4) Å, V = = 1206.77(7) Å3, and Z = 3. The simplified crystal chemical formula derived from the structure refinement is: ANa3B(Na2.7□0.3)Σ3C(Na1.8Mn0.2)Σ2MZrSi6O18. The IR spectrum shows only trace amount of OH groups. Townendite serves as a proto-phase for the formation in nature of Ca- and Mn-poor (Ca + Mn 0.5 apfu) OH-bearing lovozerite-group zirconosilicates. Two different in crystal chemical mechanism natural evolution series are found: (1) townendite ANa3BNa3CNa2MZrSi6O18 → kapustinite ANa3B(Na2–3□0–1)C□2MZrSi6O15–16(OH)2–3 → → litvinskite A(Na2–3□0–1)B(□,H2O)3C□2MZrSi6O13–14(OH)5–6; (2) townendite → zolotarevite ANa3B(H2O,□)3CNa2MZrSi6O15(OH)3 → litvinskite. The abundance of products of townendite alteration in near-surface rocks of the Lovozero complex shows that this mineral is widespread in deep levels of the pluton in “fresh” peralkaline intrusive rocks and pegmatites and is (1) a bright indicator of extremally high agpaicity and (2) an important, sporadically main concentrator of Zr and Hf in them. The major amount of townendite occurs in unaltered rocks of the fifth intrusive phase of the Lovozero pluton which are protholith rocks of the well-known porphyry-like lovozerite lujavrites.
Hundred-Year-Old History of Reviews of Newly Discovered Minerals. Personalia
Authors: Smolianinova V. N. , Borisova E. A.
Published: April 2024

The article traces the history of annual reviews of newly discovered minerals published in the magazine Zapiski Rossiiskogo Mineralogicheskogo Obshchestva (Proceedings of the Russian Mineralogical Society), the first experience of their publication, and the further development. The first reviews were published by O.M. Shubnikova, and the very first of them has been written in co-authorship with D.I. Yuferov; it covered the period of time from 1922 through 1932. Later, during the time, reviews were regularly composed and published by E.N. Bonshtedt-Kupletskaya, T.A. Yakovlevskaya, V.I. Kudryashova, and V.N. Smolianinova.
Determination of the Iron Oxidation State in Cr-Spinels by Electron Microprobe X-ray Emission Spectroscopy of Lα,β Lines
Authors: Votyakov S. L. , Zamyatin D. A. , Danilenko I. A , Chashchukhin I. S.
Published: April 2024

The oxidation state of Fe, Cu, Eu, Ce, etc. in minerals is an important indicator of redox conditions for their formation and evolution. In this work, the features of X-ray emission Fe Lα,β spectra (XES) obtained by Cameca SX100 microprobe, as well as the Mössbauer spectra of Cr-spinels of various compositions from a number of the Urals ultramafic massifs, have been studied. Using microprobe data on the composition and homogeneity of the grains, as well as the Fe3+/\({\text{Fe}}_{{{\text{tot}}}}^{{{\text{M\"o ssb}}}},\) 19 intralaboratory reference samples have been selected from a large number of the Urals Cr-spinels. Based on the analysis of BSE images and maps of the distribution of elements in Cr-spinel grains, the most homogeneous ones were identified. It was shown that, up to the determination error, Fe3+/\({\text{Fe}}_{{{\text{tot}}}}^{{{\text{M\"o ssb}}}}\) coincides with that obtained in the framework for calculation approach based on microprobe data on the composition and assumptions about the mineral stoichiometry. For determination of Fe oxidation state by XES data, it has been proposed to use as a calibration dependence for intralaboratory reference samples the position of the maximum of Fe Lα line on the content of Fe2+; the latter is satisfactorily approximated by a linear function (rxy = 0.96); the relative error of Fe2+ determination is 2%. Approbation of the developed approach was carried out on a series of control samples of Cr-spinels; the obtained values of Fe2+ and Fe3+/Fetot agree satisfactorily with the Mössbauer and calculated data in the stoichiometric approximation.
Behavior of the Crystal Structure of Leightonite K2Ca2Cu(SO4)4⋅2H2O in the Temperature Interval from –180 to 325 °C
Authors: Demina S. V. , Shablinskii A. P. , Filatov S. K. , Biryukov Y. P. , Vergasova L. P. , Krzhizhanovskaya M. G. , Bubnova R. S. , Moskaleva S. V.
Published: April 2024

This paper presents the results of mineralogical and crystal chemical studies of leightonite K2Ca2Cu(SO4)4·2H2O from the Kamchatka Peninsula (Russia), including an investigation of its thermal behavior in a wide temperature range (–180 ≤ T ≤ 325 °C). The following methods were used: energy dispersive X-ray spectral analysis, single-crystal and powder X-ray diffraction, and in situ powder X-ray diffraction (at room, negative and high temperatures). The temperature range of the existence of the mineral are established, the main values of the thermal expansion tensor are calculated, and a structural interpretation of thermal expansion is given. The mineral crystallizes in the monoclinic system, space group C2/c, a = = 11.734(2), b = 7.596(1), c = 10.176(1) Å, β = 124.85(1), V = 744.4(2) Å3, Z = 2. The crystal structure was refined to R = 0.065. The average empirical formula is K2.31Ca1.99Cu0.88Al0.04S3.97O16·2H2O. Leightonite is stable up to ~325 °C and above this temperature it decomposes onto high-temperature calciolangbeinite-C K2Ca2(SO4)3 (P213) and chalcocyanite CuSO4 phases. Thermal expansion coefficients are: α11 = 8.3(9), α22 = 3.6(4), α33 = –4.7(5) × 10–6 °C–1 at –180 °C и α11 = 41.6(5), α22 =36.5(5), α33 = –10.6(1) × 10–6 °C–1 at 325 °C).
Major Rock-Forming Minerals of Paralava in Mongolian Combustion Metamorphic Complexes
Authors: Glushkova V. E. , Peretyazhko I. S. , Savina E. A. , Khromova Е. А.
Published: April 2024

Paralavas of combustion metamorphic complexes in Mongolia were formed in high-temperature conditions from carbonate-terrigenous rocks of sedimentary formations due to to multistage spontaneous underground coal fires. Melilite-nepheline paralavas contain phenocrysts of Fe-rich åkermanite-alumoåkermanite, clinopyroxene of the diopside–hedenbergite series containing up to 49 mol. % of kushiorite end-member, and basic plagioclase. Enstatite-ferrosilite is the rock-forming mineral in paralavas of the plagioclase-pyroxene ± ± indialite composition. Paralavas often contain xenoliths of thermally altered sedimentary rocks. Mineral associations in remnant xenoliths of marly limestone are composed of gehlenite, minerals of the monticellite–kirschsteinite series, perovskite, Al-rich clinopyroxene, spinel, and other minerals. They were formed both at the stage of the high-temperature metamorphism of sedimentary protolite, preceding the melting of carbonate-silicate rocks, and as a result of the reactionary interaction between xenoliths and pyrogenic silicate melts of different composition.
Crystal Formation during Thermal Oxidation of Shungite
Authors: Tovpenets T. Yu.
Published: April 2024

Micro-sized crystals formed during the thermal oxidation of shungite have been studied using scanning electron microscopy and Raman spectroscopy. According to Raman spectroscopy, there were identified bultfonteinite, allanite, and cornubite, which were not detected before in study of the initial shungite samples. Conditions of their formation suggest that the mechanism of these crystals growth is the desublimation.
Contamination in Mineralogy: Pathways and Effects
Authors: Afanasiev V. P. , Pokhilenko N. P.
Published: April 2024

Contamination is considered as the ingress of material into an object that is not characteristic of this object. From this point of view, technogenic contamination, associated with human activity, and natural contamination, not depending on humans, are distinguished. The study of contamination is relevant in relation to the research process: neglect or misunderstanding of this phenomenon can lead and often lead to erroneous conclusions, forecasts, and estimates regarding the objects of study. Contamination does not necessarily have a negative meaning, and both types of contamination can be useful. Both types of contamination are considered on specific examples.
DFT Modeling of the Hydrogen Bonding System in Sampleite
Authors: Panikorovskii T. L. , Yakovenchuk V. N. , Pakhomovsky Ya. A. , Konoplyova N. G. , Ivanyuk G. Yu. , Antonov A. A. , Shilovskikh V. V. , Krivovichev S. V.
Published: April 2024

The article provides a crystal chemical description of the second find of the P21/n modification of NaCaCu5(PO4)4Cl∙5H2O sampleite found at the Kester tin ore deposit. The mineral formation is genetically related to low-temperature oxidation processes of primary copper, zinc, and tin sulfides as well as to the formation of later Cu-, Zn-phosphates such as batagayite, epifanovite and sergeysmirnovite. The positions of hydrogen atoms in the structure of sampleite have been calculated with the DFT-method. The comparison of the real and theoretical IR spectra was carried out as an assessment of the reliability of the theoretical calculations. Sampleite was formed at the stage of hydrothermal alteration of Sn, Cu and Zn sulfide minerals and co-exists with epifanovite NaCaCu5(PO4)4[AsO2(OH)2]∙7H2O, which is undoubtedly a later one, but has a lower complexity (IG,total), 474.24 than sampleite 933.32 (bit/cel).
On the Allocation of Regional Geological Monuments of the Main Devonian Field
Authors: Cinkoburova M. G. , Norova L. P.
Published: April 2024

Abstract—Using the example of two particularly valuable geological objects of the Main Devonian Field (Ilmen glint and the valley of the Velikaya River in the area of the Vybuty rapids), the features of the allocation and protection of geological monuments of regional significance are considered. Ilmen glint is a complex (stratigraphic, paleontological, ore-litho-petrological, hydrogeological) geological monument of regional significance. The authors substantiate the paleogeographic value of the object, which consists in the possibility of studying various ecological complexes of the macrofauna of the Middle Frasnian Sea, reflecting both regressive and transgressive stages of its development. Also, for the Ilmen glint are recommended two new criteria: a historical criterion (reflection of information about a geological object in the classical geological literature) and (for the first time) the introduction of a new historical and geographical criterion (the relationship of geological and geographical features with the history of settlement and development of the region). As a unique geological object, Ilmen glint has been studied by outstanding Russian and foreign researchers. The sections of the glint and the near-glint region are stratotypic for a number of sub-regional and local subdivisions of the Middle Frasnian of the Main Devonian Field. The features of the geological structure (close occurrence to the surface of carbonate rocks of the Upper Devonian), proximity to Novgorod and convenient communication with it by water influenced the fact that this area became one of the areas of ancient mining back in the days of Veliky Novgorod. Due to the location at the crossroads of important roads, the surroundings of glint often turned out to be the scene of important historical events, so in the village of Korostyn, located at the western tip of glint, the famous Korostyn Peace was concluded. The Vybuty Rapids tract is not a protected area, although it also has a clear scientific value from the paleogeographic (interesting complexes of ichnofossils are observed in the outcrop and extremely valuable in the reconstruction of paleogeographic conditions of the hardground facies) and historical and geographical points of view (a large ford was the strategic place in the Middle Ages for Pskov). The article considers the influence of natural and anthropogenic hazards on the condition of the described geological objects. In the described unique outcrops, there is an active manifestation of landslide processes and weathering processes. At the same time, the terrain features (the presence of local plicative and disjunctive structures that contribute to the formation of zones of increased fracturing) are aggravated by the active traffic load in the areas adjacent to the coastal cliffs.
Landscape and Ecological Analysis of the Territory of the Surgut District of Khmao-Yugra
Authors: Kuznetsova E. A. , Kichikova М. А.
Published: April 2024

Abstract—The landscape and environmental analysis was carried out on the example of the Surgut district of the Khanty-Mansiysk Autonomous Okrug-Yugra, where the main factor in the degradation of natural objects is pollution of the territory as a result of mining, which accounts for up to 80% of emissions. Landscape provinces as nodal geosystems were used for the analysis. A general structural and morphological assessment of landscapes, an assessment of unfavorable ecological and geographical processes, anthropogenic transformation and ecological infrastructure of landscapes were carried out, and ecologically significant factors of the territory were identified. As a result of the conducted research, a map was compiled reflecting the spatial differentiation of the state of landscape provinces, taking into account anthropogenic impact. It has been established that the best landscape and ecological well-being is possessed by the southern territory of the district (Yugansk-Laryegan province), which is characterized by the containment of anthropogenic activity due to the creation of the Yugansk Nature Reserve. The Vandras-Yugan province serves as a buffer between anthropogenic and least modified natural landscapes, occupying an intermediate position in the assessment. The central part of the Surgut district received the most massive "blow" to the landscapes, as the main transport routes, pipelines, and residential settlements are concentrated here. The northern part of the Surgut district is characterized by waterlogging processes, a high degree of overgrowth and an average degree of transformation of natural landscapes.
Seasonal and Inter-Annual Variability of Water Temperature in Petrozavodsk Bay of Lake Onega
Authors: Zdorovennova G. E. , Zdorovennov R. E. , Palshin N. I. , Efremova T. V.
Published: April 2024

Abstract—Based on year-round measurements of water temperature at an autonomous station (an anchored chain equipped with temperature sensors), the features of the temperature and ice regimes of the Petrozavodsk Bay of Onega Lake in modern climatic conditions were studied; the dates and duration of the main hydrological phenomena in the water area of the bay were specified. In the abnormally warm winter of 2019–2020, the water area of the Petrozavodsk Bay was not completely covered with ice for the first time in a long period of observations; in the area of the measurement station, ice fields were observed from late January to mid-March. The duration of ice-covered period in the next two winters was 3.5 and 5 months. Data were obtained on the timing of the onset and duration of the spring under-ice convection, a phenomenon that plays an important role in the thermal regime of the lake at the end of winter. It is shown that 2016, 2021 and 2022 spring under-ice convective mixing lasted 4–6.5 weeks, covering the entire water column by the end of ice period. Mixing of the water column after breaking the ice (spring homothermy) continued for another 3–4 weeks. In the spring of 2020, under-ice convection was not observed; spring overturn continued for two months from mid-March to mid-May. The dates of the upward transition of water temperature through 4°C in the years of measurements (5–19 May) were ahead of the long-term average by 2–3 weeks (end of May). Thermal stratification was established from 12 to 27 May and existed for 3–3.5 months. Complete mixing of the water mass of the bay took place in late August–early September, and then, until ice settling, the water column cooled in a state of homothermy. Immediately before ice formation, the water temperature dropped to very low values and did not exceed 0.1°С in the water column. The period with an average daily water temperature of the surface layer of the Petrozavodsk Bay above 10°C lasted from 121 to 144 days during the years of measurements.
Modeling of melting-freezing of ice in problem of fluid flow along a small irregularity
Authors: Gaidukov P. K. , Danilov V. G. , Fonareva A. V.
Published: April 2024

In this paper, we study the phase transition in a fluid flow along an ice surface with a small localized irregularity for large Reynolds numbers. In the framework of the double-deck structure of the boundary layer, a mathematical modelbased on the phase field system is constructed that describes the dynamics of the phase transition, and the results of numerical simulation are presented.
Effect of Small Angles of Attack on Turbulence Generation in Supersonic Boundary Layers on Swept Wings
Authors: Kosinov A. D. , Kocharin V. L. , Liverko A. V. , Semionov A. N. , Semionov N. V. , Smorodsky B. V. , Tolkachev S. N. , Yatskikh A. A.
Published: April 2024

We present the new (for Mach numbers М = 3 and 3.5) and generalizing (for Mach numbers from 2 to 4) results of experimental investigations on the effect of small angles of attack on laminar-turbulent transition in the supersonic boundary layer on a swept wing with the leading-edge slip angle of 72°. The angle-of-attack variation has a strong effect on the transition Reynolds number. The transition Reynolds number decreases with increase in the Mach number. The measurements were carried out by means of a constant-temperature hot-wire anemometer using the proven procedure of determining the transition location. The eN method is used for the first time for numerically estimating the transition Reynolds numbers in the supersonic boundary layer on a swept wing with the leading-edge slip angle of 72°. The growth of the amplitudes of the steady and unsteady modes of the boundary layer crossflow are calculated in accordance with the linear stability theory, within the framework of the Lees–Lin system of equations. The numerical results indicate that, in accordance with the experimental results, laminar-turbulent transition in the boundary layer on the model swept wing is governed by the growth of stationary modes of the crossflow instability.
Numerical Modeling of Supersonic Flow with a Region of Heat Release by a Longitudinal-Transverse Discharge
Authors: Kornev K. N. , Logunov A. A. , Shibkov V. M.
Published: April 2024

Steady supersonic air flow in a diverging aerodynamic channel of rectangular cross-section is numerically simulated. The channel represents a laboratory model of an air-breathing straight-flow engine. The aerodynamic model is validated using the experimental data for the case in which the zone of volumetric heat release is absent. After the model has been validated a supersonic flow with a built-in zone of volumetric heat release was numerically simulated. Three-dimensional distributions of the velocity, temperature, and pressure in a steady supersonic air flow are obtained. It is shown that in the case, in which the volumetric density of the heat power of the source is equivalent to the mean total power of the discharge W = 10 kW, the discharge heats the gas up to the temperature T = 1700 to 4200 K, which leads to flow acceleration without its thermal choking. When the thermal power density of the source is equivalent to the mean common discharge power W = 20 kW, the gas is heated more strongly, up to 6700 K, but then local thermal choking of the flow occurs.
CONDITIONS OF DEEP-WATER UNDERCURRENTS GENERATION IN THE NORTH-EASTERN BLACK SEA
Authors: Markova N. V. , Dymova O. A.
Published: April 2024

A research of the occurrence factors of narrow non-stationary movements formed in the Black Sea in the lower part of the constant piccoline and deeper is performed. Such currents spread along the continental slope against the predominant cyclonic direction of surface circulation (undercurrents) are observed from several days to several weeks and have a width of 8 to 12 km. The prerequisites for the generation of undercurrents in the Black Sea hydrophysical fields are studied on the example of its north-eastern region, where the undercurrents are fixed most often. The numerical experiment results are analyzed to calculate the hydrophysical fields based on the numerical z-model of MHI with a horizontal resolution of 1.6 km. The experiment is carried out for the 2016-2017 period with assimilation in the model of hydrological observations of temperature and salinity. ERA5 data are used to set atmospheric forcing. The undercurrents are fixed twice in September 2016 and February 2017 according to the observations of the ARGO float ID6901833 in the area of the North Caucasus coast. A change in the direction of currents in the specified area (from cyclonic to anticyclonic and back) is reconstructed in the numerical experiment. Fields of basic hydrophysical parameters and some of their derivative characteristics are built and analyzed. The influence of mesoscale anticyclonic eddies, as well as gradients of the sea water density on the structure and variability of the velocity field in the north-eastern part of the sea is shown. According to the simulation results, narrow undercurrents into which Argo float fell in the fall of 2016 and in the winter of 2017 are distributed within a few days in the anticyclonic direction along the continental slope on horizons from 50–100 to 500 m, and their formation occurred under the conditions of weakening cyclonic Main Black Sea current in the upper layer of the sea and the increase in the Kerch anticyclonic eddy.
Dusty Gas Flow past Bodies under Scattering of Rebounded Particles
Authors: Panfilov S. V. , Romanyuk D. A. , Tsirkunov Yu. M.
Published: April 2024

Two-phase gas-particle flow over a flat plate of finite thickness in a channel at a high subsonic velocity and supersonic transverse flow past a cylinder are considered. The leading edge of the plate is wedge-shaped or represents a smooth bluntness of constant radius. The wedge surface and the front bluntness are specified both smooth and rough. The roughness is modeled by a two-dimensional profile based on an experiment. Spherical particles and a mixture of particles in the form of ellipsoids of revolution, rectangular prisms, prisms with flat-cut vertices, and tetrahedrons are considered. The parameters of each of the forms vary. The impact interaction model proposed earlier and consistent with the experimental data on the coefficients of restitution of the center-of-mass velocity is used to determine the translational and rotational velocities of non-spherical particles after rebound. Along with monosized particles, a dispersed phase with a spread of particles in size is considered. The role of the studied factors of random nature which affect the flow pattern and the dispersed phase parameters is found.
Self-Similar Solution to the Problem of Unsteady Film Condensation on a Vertical Semi-Infinite Plate
Authors: Kuroedov A. A. , Laptev I. V. , Suvorov A. V. , Cherkasov S. G.
Published: April 2024

Changes in the regimes of condensate film flow along the underlying surface in the presence of a body force are considered within the framework of a simplified physical and mathematical model of hydrodynamic and thermal processes occurring under unsteady film condensation on a vertical semi-infinite plate. The model is used to determine the applicability conditions of the zero-gravity approximation when considering film condensation. It is found that the validity of using the zero-gravity approximation to calculate the film thickness growth rate on any plate section depends not only on the magnitude of the body force, but also on time and distance between this section and the leading edge of the plate.
Steady Gas-Droplet Flow Pattern and Heat Transfer Behind the Point of Incidence of a Shock Wave on a Flat Wall
Authors: Golubkina I. V. , Osiptsov A. N.
Published: April 2024

The structure of a steady 2D gas-droplet flow in the near-wall region behind the point of incidence of a normal or an oblique shock wave on a plane wall is investigated. In this case, the normal wave corresponds to the Mach stem in the Mach reflection mode, and the oblique wave corresponds to the regular reflection mode of the incident oblique wave. The main aim of the study is to evaluate the effect of small liquid droplets present in the free stream on the equilibrium temperature of the adiabatic wall behind the point of wave reflection. The question is investigated: to what extent the presence of an oblique shock wave incident on the wall can enhance the effect of reducing the equilibrium wall temperature by small droplets present in the flow. The flow region is split into the outer region of “effectively inviscid flow” and the region of an asymptotic laminar boundary layer. Flow calculations in each region are based on a two-fluid model of a gas-droplet mixture, taking into account the phase transition (evaporation) on the droplet surface. The most interesting wave configurations from the point of view of heat transfer, corresponding to “fully and partially dispersed waves” with incomplete evaporation of droplets behind the reflected wave, are studied. A simple limiting scheme of the formation of a liquid film by droplets deposited on the wall is adopted, with the effects of film instability and spattering being ignored. Based on numerical calculations, the estimates are obtained for the possible decrease in the equilibrium temperature of the adiabatic wall behind the point of incidence of a shock wave in a steady supersonic gas flow containing a low concentration of liquid droplets.
Radiative-convective heating of the surface of the Martian descent vehicle MSL with allowance for the turbulent nature of the flow
Authors: Surzhikov S. T.
Published: April 2024

A spatial computer model based on the Reynolds-averaged Navier-Stokes equations together with the Baldwin-Lomax and Prandtl algebraic models of turbulent mixing was used to calculate the radiative-convective heat transfer on the surface of the MSL descent vehicle. The intensification of convective heat transfer on the leeward side of the frontal aerodynamic shield and the superiority of the radiative heat flux density over the convective one on the rear surface are shown. The calculations were performed using the model of a physically and chemically nonequilibrium gas. A comparison is made with the results of calculations using other computational models and with flight data on the heat load on the descent vehicle obtained during the MSL descent in the dense layers of the Martian atmosphere.
Laminar Swirling Wall Jets
Authors: Gaifullin A. M. , Shcheglov A. S.
Published: April 2024

The problem of determining the characteristics of a laminar swirling wall jet of an incompressible fluid is considered. Numerical solutions of the Navier–Stokes equations are obtained in the stationary and non-statitonary formulations. It is shown that the jet characteristics obey a self-similar law at large distances from the jet source, as in the case of a three-dimensional laminar non-swirling jet, but in our case the jet propagates at a certain angle to the initial direction of jet blowing. With a large swirling of flow in the jet, regions of recirculation flow appear and the jet flow becomes unsteady.
Numerical Estimates of the Influence of Ion Diffusion on Injection-Type Electroconvection in the Plane Layer of a Low-Conductivity Fluid
Authors: Ermolaev I. A.
Published: April 2024

The influence of diffusion on isothermal electroconvective flow of a low- conductivity fluid under unipolar injection in the constant electric field in a plane-parallel electrode system is studied. The dependences of the space charge density and flow fields on the diffusion intensity are obtained. The diffusion coefficient of injected ions is numerically estimated for TO + I2. The results obtained are based on comparison of the numerical experiment with the available experimental data.
Kinetic Theory of Expansion of Two-Component Plasma in a Plane Vacuum Diode
Authors: Kokovin A. O. , Kozhevnikov V. Yu. , Kozyrev A. V. , Igumnov V. S. , Semenyuk N. S.
Published: April 2024

The results of study of the initial stage of expansion of a collisionless plasma with the electric current into a plane vacuum gap on the basis of kinetic equations for electrons and ions and the Poisson equation for the electric field are given. Self-consistent dynamics of a two-component plasma and electric field are theoretically modeled and the fundamental mechanism for establishing superthermal velocities of charged particles is described in detail. The parameters of anode-directed flows of positive ions in the cathode plume plasma are calculated. The expansion velocities of the cathode plume plasma observed in vacuum arcs at the level of (1−5) × 106 cm/s can be explained within the framework of the proposed collisionless mechanism.
Connectivity of Photosynthesis and Respiration with Content of Chlorophyll Pigments in Plants of Reed Fescue Festuca arundinacea Schreb. Under the Impact of Alkanes and Aromatic Hydrocarbons
Authors: Tyulkova E. G. , Savchenko G. E. , Kabashnikova L. F.
Published: April 2024

The association of degradation of membrane-bound chlorophyll with changes in dark respiration rates and photosynthesis in Festuca arundinacea Schreb. leaves under the influence of various concentrations of limit and aromatic hydrocarbons present in technogenic emissions was studied. 1 day after intoxication a negative correlation between the content of non-phytol forms of pigments and the rate of photosynthesis was found. Positive correlation was found between the content of: 1) phytol forms and the rate of photosynthesis; 2) non-phytol forms and respiration rate. The relationships between the processes changed after 3 days characterizing the detoxifying and adaptability of plants.
Taxonomic Assessment of the Karyological Characteristics of Sable (Martes zibellina) and Other Representatives of the Ginus Martes (Carnivora, Mammalia)
Authors: Malygin V. M. , Safronova L. D. , Sergeev E. G. , Levenkova E. S.
Published: April 2024

A revision of the original description of the karyotype of the sable Martes zibellina was carried out, data on the mitotic metaphase chromosomes of the female and male of this species and a comparison of their sets with those of closely related species of the genus Martes are presented. We also provide a description of the synaptonemal complex (SC) in the early – middle prophase of meiosis in sable spermatocytes. Comparative analysis confirmed the stability and similarity of the main cytogenetic parameters of sables and martens (2n = 38, NFa = 64–68, X is the average submetacentric, and Y is the smallest meta,-submeta,- or acrocentric). A small polymorphism associated with the representation of one- or two-armed smallest elements of the diploid set of chromosomes was revealed. These features are of little use for the development of intraspecific taxonomy of sable, but can be used to reveal phylogenetic relationships at the species and generic levels, as well as to identify the consequences of natural hybridization of closely related species of the genus Martes.
Microcystin-LR Biodestruction by Autochthonous Microbiota of Different Water Bodies in the North-West of Russia
Authors: Medvedeva N. G. , Zaytseva T. B. , Kuzikova I. L. , Chernova E. N.
Published: April 2024

The ability of the autochthonous microbiota of different water bodies in the North-West of the Russian Federation to degrade the highly toxic microcystin-LR (MC-LR) was shown for the first time. The maximum rate of degradation of MC-LR was noted in water samples from the Sestroretskij Razliv Lake and the Lower Suzdal Lake during the period of mass development of cyanobacteria. In water samples from Lake Ladoga, where no toxic cyanobacterial blooms were previously noted, MC-LR biodegradation proceeded at a much lower rate and with a longer lag phase. The composition of MC-LR biodegradation products indicates the presence in the autochthonous microbiota of the studied objects of microorganisms capable of degrading microcystins both by the mlr mechanism and by the biochemical pathway involving glutathione.
Body and Digestive Tract Sizes in Small Phytophagous Mammals: Influence of Ecological and Physiological Factors
Authors: Naumova E. I. , Chistova T. Yu. , Zharova G. K.
Published: April 2024

The question of the size ratio of the body and the digestive tract (DT) in small phytophagous mammals is considered on the example of gerbils (Gerbillidae), a group of rodents that is exceptionally convenient for studying such relationships due to significant differences in body weight and morphological homogeneity of the DT. We analyzed the weight ratios of body size and DT, wet weight of contents and tissues of DT in 6 species of gerbils with a 10-fold body weight range (average 18 to 175 g) coexisting in the Negev desert – Psammomys obesus, Meriones crassus, Gerbillus pyramidum, Gerbillus allenbyi, Gerbillus dasyurus Gerbillus henleyi. In a number of studied species of small mammals weighing less than 0.5 kg, no linear relationship was found between body size and DT. The allometry of the considered indicators is mainly due to environmental and physiological factors.
Physicochemical and Sorption Characteristics of the Hermetia illucens Fly Pupal Cuticle
Authors: Sverguzova S. V. , Shaikhiev I. G. , Sapronova Zh. A. , Svyatchenko A. V. , Ushakova N. A.
Published: April 2024

Physicochemical and sorption characteristics of the Black Soldier fly pupal cuticle have been studied. The qualitative and granulometric compositions of chitin material were determined, and the surface microrelief of chitin particles was studied by scanning microscopy. The sorption properties of the material were studied using the methylene blue dye. It was found that the sorption capacity of the material is 0.118 mmol/g, or about 38 mg/g. Mathematical processing of the sorption isotherm using the Langmuir, Freindlich, Dubinin-Radushkevich models showed that the process is best described by the Dubinin-Radushkevich model (R2 = 0.8031), and the sorption process has a physical nature (E = 5.534 kJ/mol).
Morpho-Physiological Determinants of Potato Yield Formation under Conditions of Moisture Deficiency and High Temperatures
Authors: Bakunov A. L. , Dmitrieva N. N. , Rubtsov S. L. , Milekhin A. V. , Nesterov V. N. , Bogdanova E. S. , Rozentsvet O. A.
Published: April 2024

Morphological and physiological parameters of leaves and tubers of 22 varieties of potato (Solanum tuberosum) were investigated. Discriminant analysis found that stomata size (12%), chlorophyll content (10%), number of tubers (29%), and average tuber weight (21%) determined the gradation of plants by yield. The specific surface density of leaves (38%), the content of chlorophyll (13%) and carotenoids (13%), and leaf area (12%) made the greatest contribution to discrimination in relation to ecological plasticity. It is concluded that the number of stomata per unit area of the leaf, the specific surface density of the leaf and the content of photosynthetic pigments are the key characteristics that contribute to both high yield and adaptive capacity of potatoes.
To the Stady of a Water Vole (Arvicola anphibius) at the North-Western Area
Authors: Ivanter E. V.
Published: April 2024

We have conducted the long-term expeditionary and stationary studies in the taiga Northwest of Russia (1958–2018) to characterize the population, biotopic distribution, nutrition, reproduction, spatial and ecological structure of the population, and the dynamics of the number of water voles, including those associated with its habitat in northern range boundaries: timing, reproductive cycles, course and intensity of reproduction, participation in the reproduction of individual age groups, variations in brood size, etc. The breeding season from the first pregnant females are caught in spring to the last newly born females in autumn lasts 4–6 months. It depends on the state of the population and weather and phenological conditions of the year. The average brood in wintering and arrived female voles in our region was close to the species norm and amounted to 6.5 ± 0.37 and 5.7 ± 0.41. The main reasons for the long-term dynamics of the species abundance are changes in the hydrological regime of water bodies.
Sex Differences in Age-Related Changes in Functional Activity and Expression of the Main Regulatory Proteins of the Renin-Angiotensin System in the Aorta and Myocardium of Rats
Authors: Kozhevnikova L. M. , Sukhanova I. F.
Published: April 2024

The sex differences of age-related changes in the functional activity and expression of receptor and regulatory proteins of the renin-angiotensin system (RAS) in the aorta and myocardium of rats is evaluated. It was found that with age in females, the sensitivity of the aorta to the vasoconstriction action of angiotensin II increases, while in older males it remains unchanged. In the aorta of old females, a decrease in the mRNA levels of ACE, MasR and ACE2 was revealed by 1.6, 1.8 and 4.4 times, respectively. It has been shown that during aging in the left ventricle of females, the level of MasR and ACE2 mRNA decreases, in males, on the contrary, the level of ACE and MasR mRNA increases. The results obtained indicate the sexual characteristics of age-related changes in RAS activity in the vessels and heart of rats.
Role of Albumin and Alpha-Fetoprotein in Prenatal Ontogenesis of the Human Eye
Authors: Panova I. G. , Tatikolov A. S.
Published: April 2024

The vitreous body of the eye of human fetuses contains serum albumin (SA) and alpha-fetoprotein (AFP), which is normally characteristic of human embryos and fetuses. In the second trimester, both proteins are found in the vitreous at a concentration comparable to that in blood serum, after which their content decreases sharply. In this analytical review, taking into account the biological properties of SA and AFP, the role of these proteins in the processes of growth and differentiation of the structures of the developing eye is discussed.
Unicellular Plankton Size Structure (Size-Taxonomic and Size-Trophic Spectra) in a Hypertrophic Urban Lake
Authors: Umanskaya M. V. , Bykova S. V. , Tarasova N. G.
Published: April 2024

The results of an analysis of the size spectra of unicellular plankton (bacteria, algae, ciliates) in the hypertrophic freshwater urban lake (L. Bolshoe Vasilyevskoe, Togliatti, Russia) are presented. Two types of size spectra have been identified in the seasonal cycle. Strong nanoplanctonic maximum formed mainly by phototrophic cyanobacteria and Chlorophyta was found during the period of open water (spring to autumn); picoplankton maximum/maxima (mainly heterotrophic bacteria) and increased proportion of microplankton (heterotrophic and mixotrophic ciliates)–in the ice period. The peculiarity of the studied lake, in contrast to less productive ones is the stability of the plankton size structure over the past 25 years.
Photochemistry and Signaling Activities of Plant Cryptochromes. Review
Authors: Fraikin G. Ya. , Belenikina N. S.
Published: April 2024

Cryptochromes compose the widespread class of blue-light sensory receptors that in plants regulate processes of development and circadian rhythm. These photoreceptors can also function as magnetoreceptors. Cryptochrome proteins bind flavin adenine dinucleotide (FAD) as a chromophore in the photolyase homology region (PHR) domain and contain the C-terminal extension (CCE) which is joined to PHR near the FAD-binding site. The cryptochrome activation is initiated by photochemical FAD conversions involving electron/proton transfer and the formation of redox forms. In plants, cryptochrome protein with photoreduced FAD undergoes conformational changes causing disengagement of the PHR domain and CCE that is accompanied by the formation of functionally active oligomers of cryptochrome molecules. Photooligomerization is considered as a key process necessary for cryptochrome signaling activity.
Development and Architecture of the Nepeta transiliensis (Lamiaceae) Rhizome
Authors: Cheryomushkina V. A. , Astashenkov A. Yu. , Komarevtseva E. K. , Guseva A. A.
Published: April 2024

The ontogeny and structural organization of the rhizome of Nepeta transiliensis individuals in the high-mountain conditions of the Zailiyskiy Alatau have been studied. Various types of buds (renewal buds, dormant buds) take part in shoot formation, from which various types of elongated shoots are formed. Using the architectural approach to the description of plants, the main structural units – rhizome modules – are identified. Different branching of modules leads to the construction of different rhizome axes. In the rhizomatous axes, the angles of departure of the lateral modules from the maternal one differ, the development of the modules occurs sequentially from the renewal buds or with a delay from the dormant buds. The set of rhizomatous axes forms a branched rhizome complex and leads to the formation of rhizome tiers. In general, the rhizome of N. transiliensis is of the “intermediate” type, which combines the features of a geometric and non-geometric rhizome.
Homeostatic Mechanisms of Biological Systems: Prolegomena
Authors: Zakharov V. M. , Trofimov I. E.
Published: April 2024

The stability of biological systems ensures their viability under the influence of environmental factors. The homeostatic mechanisms of the body ensure the stability of the process of individual development (developmental homeostasis, or homeoresis). The stability of biosystems of a higher rank is determined by the diversity and stability of the constituent elements. New opportunities for the implementation of homeostatic mechanisms appear at the level of society.
Ecological Biochemical Adaptations in Aquatic Organisms
Authors: Nemova N. N.
Published: April 2024

The general ideas regarding ecological biochemical adaptations in aquatic organisms based on the results obtained by using a set of field and experimental methods over decades of research on members of marine and freshwater fish fauna and on their food items (molluscs, crustaceans) carried out by the Ecological Biochemistry Think Tank team. Examples of biochemical adaptations in aquatic organisms are provided. Certain conclusions are drawn regarding the common and specific pattern of metabolic adaptive response in the studied organisms growing and developing under normal conditions and upon changes in the environment. The results improve our understanding of the mechanisms behind ecological biochemical adaptations and their role in maintaining homeostasis in aquatic organisms.
Ecological Niches Modelling of the Most Dangerous Invasive Species Top-100 in Russia: Testing the Hypothesis of Conservatism of Ecological Niches
Authors: Petrosyan V. G. , Osipov F. A. , Feneva I. Yu. , Dergunova N. N. , Khlyap L. A.
Published: April 2024

The concept of ecological niches plays an important role in predicting the potential distribution of species in the invasive range and developing invasion management strategies. To test the hypothesis, we used models of ecological niches of the 100 most dangerous invasive species of Russia. Our results show that invasive niches occupy a position similar to native niches in the space of predictor variables and there is a very limited expansion of niches. The results generally support the niche conservatism hypothesis. We also found important exceptional cases of rejection of this hypothesis. The key mechanisms governing the persistence of niche increase our confidence in availability species distribution models to predict the response of species in the framework of ongoing of global climate change.
Gene Diversity of Major Histocompatibility Complex Class I of the Far Eastern Leopard (Panthera pardus orientalis)
Authors: Tarasyan K. K. , Sorokin P. A. , Kholodova M. V. , Naidenko S. V. , Rozhnov V. V.
Published: April 2024

The study presents the status and diversity of major histocompatibility complex (MHC) class I genes in the Far Eastern leopard (Panthera pardus orientalis). 20 alleles of MHC genes were obtained from 11 samples in total, 19 alleles were described for the first time for the species. A high diversity of alleles is shown at the level of individuals as well as at the population level. Comparison of MHC gene polymorphism in leopard subspecies showed that the genetic diversity of the Far Eastern leopard is not lower and even possibly higher, than observed of the African and Indian subspecies. The high allelic diversity of the Far Eastern leopard genes is supported by the positive selection affecting on the antigen-binding region of the protein product they encrypt. It is concluded that the low abundance of the Far Eastern leopard has not yet led to irreparable losses in the genetic potential of the population.