bluuebunny/crossref_metadata_2025 huggingface dataset:
Tectonics of the Continental Barents Sea Shelf (Russia): Formation Stages of Basement and Sedimentary Cover
Authors: Grushevskaya O. V. , Soloviev A. V. , Vasilyeva E. A. , Petrushina E. P. , Aksenov I. V. , Yusupova A. R. , Shimanskiy S. V. , Peshkova I. N.
Published: April 2024

Based on the results of field complex geophysical studies in the northwestern part of the Russian sector of the Barents Sea shelf, as well as on the processing and comprehensive interpretation of new and retrospective geophysical materials in the volume of 25 500 linear kilometers and deep well drilling data in the section of the Barents Sea sedimentary cover identified regional tectonostratigraphic units: (i) Paleozoic complex (between reflecting horizons VI(PR? ) and I2(P‒T)); (ii) the Triassic complex (between reflecting horizons I2(P‒T) and B(T‒J)); (iii) the Jurassic complex (between reflecting horizons B(T‒J) and V′(J3‒K1)); (iv) the Cretaceous‒Cenozoic complex (between reflecting V′(J3‒K1) and the Barents sea floor). According to the structural analysis’ results, three structural floors are established: the lower structural floor, which includes Riphean terrigenous-affusive sediments and Lower Paleozoic‒Lower Permian terrigenous-carbonate sediments; the middle structural floor is formed mainly by carbonate sediments of Upper Devonian‒Lower Permian; the upper structural floor combines terrigenous sediments of Lower and Upper Permian, Mesozoic and Cenozoic sediments. The authors present a new tectonic model of the Barents Sea region, including elements of all structural floors with subfloors. In accordance with the tectonic zoning, paleostructural and paleotectonic analyses, the article outlines the main stages of the Barents Sea shelf development: stage of the Late Proterozoic compression and Early-Middle Paleozoic continental rifting (I), Late Paleozoic stabilization stage (II), Early Mesozoic tectogenesis stage (III), Middle Mesozoic thermal subsidence stage (IV), Late Jurassic stabilization stage (V), Cretaceous sagging stage (VI) and the final stage as a Cenozoic uplift over a large part of the Barents Sea shelf (VII). In the northwestern part of the Russian sector of the Barents Sea shelf, synchronous dipping of the sedimentary cover basement took place, associated with spreading and formation of the Arctic Ocean.
Coseismic and Tectonic Time-Scale Deformations of an Island Arc Based on Studies of East Coast of Kamchatka Peninsula (Far East, Russia)
Authors: Pinegina T. K. , Kozhurin A. I.
Published: April 2024

Geologic structure of the late Holocene accumulative marine terrace on the coast of Kamchatka Bay (Kamchatka Peninsula) has been studied. The ages and relative hypsometric position of beach ridges composing the terrace allowed us to identify two types of vertical movements of the coast: periodic fast (coseismic) and slow time-scale uplift or subsidence. Large-amplitude vertical coseismic movements (up to 1‒2 meters) occur on average once in about 1200‒1300 years, and slow movements occur at an average rate from a fraction of a millimeter to about 2 mm per year. Coseismic motions represent relaxation of elastic deformations accumulated during the interseismic interval of the seismic cycle, neither exceed them nor accumulate. Slow motions set the general trend of vertical deformations of the coast. It is assumed that the subsiding central parts of the eastern bays of Kamchatka Peninsula (Avachinsky, Kronotsky and Kamchatsky) and depressions between the eastern peninsulas (Kronotsky, Shipunsky) and the main massif of Kamchatka form an arc-parallel extension zone, which is nearest to the deep-water trench, and that extension is caused by the migration of the subducted part of the Pacific plate toward the Pacific Ocean. Under the eastern Shipunsky and Kronotsky peninsulas, the arc-normal extension of the earth’s crust of the Kamchatka segment of the Kuril-Kamchatka island arc is replaced by a zone of transverse compression.
Pre-Quaternary Evolution of the Eurasian Basin: Results of Interpretation of Seismic Profile ARC1407A
Authors: Zayonchek A. V. , Sokolov S. Yu. , Soloviev A. V.
Published: April 2024

The work examined the tectonics and stratigraphy of the Eurasian basin in pre-Quaternary times based on the results of interpretation of the ARC1407A seismic profile and calculations of the theoretical position of linear magnetic anomalies. The sedimentary packages identified on the seismic profile and their stratigraphic adjustments are close to similar studies in the western parts of the Nansen and Amundsen basins. The age assignment of sedimentary strata corresponds to the results of drilling ACEX wells and the main stages of development of the Eurasian basin. The reference horizon of ~34 million years old, previously identified in some scientific works and associated with the cessation of spreading in the western part of the North Atlantic and the entry of the Greenland Plate into the North American Plate, has not been established, which is similar to studies in the western parts of the basins of the Eurasian Basin. For the western part of the Nansen Basin, a reference horizon with an age of ~38 Ma was identified for the first time, previously traced in the western part of the Amundsen Basin, the appearance of which is associated with one of the stages in the development of the Eurekan Orogeny. Also, for the western part of the Nansen Basin, within the ARC1407A section, a reference horizon with an age of ~26 Ma, previously traced in the western part of the Amundsen Basin, is established. The appearance of this boundary is associated with the beginning of unstable spreading in the westernmost segment of the Eurasian basin between the Yermak Plateau and the Morris Jesup Rise. The end of the long stratigraphic hiatus from 44.4 to 18.2 Ma in the ACEX well section clearly correlates with the appearance of sedimentary strata with an age of ~19.6‒18.3 Ma, which confirms the point of view about the beginning of the formation of the deep-sea connection between the North Atlantic and Eurasian basins. This event coincides with a fundamental stage in the restructuring of the movements of the Eurasian and North American plates, expressed in a change in the general direction of migration of the instantaneous opening poles from north-northwest to south-southeast. It is assumed that thick sedimentary deposits in the Nansen Basin and in the rift valley of the Gakkel ridge, observed on seismic section ARC1407A are glaciomarine Late Pliocene-Quaternary in age 2.7 Ma. Apparently these deposits are making up a significant volume of sediment in the eastern part of the Eurasian Basin and the Gakkel Ridge.
The Geochemical Effect of Impact Processing of Polar Regolith on the Moon
Authors: Basilevsky A. T. , Dorofeeva V. A. , Li Yuan , Fang LiGang
Published: April 2024

The paper considers the geochemical effects of impact processing of the polar regolith of the Moon. It contains an admixture of water ice, which can (should?) provide conditions for possible chemical reactions. To date, only one geochemical effect was reliably found—the formation of hematite Fe2O3, which is uncharacteristic for relatively low selenographic latitudes. In the work, a thermodynamic analysis of the conditions required for the formation of hematite is carried out. It is shown that this requires the presence of free oxygen, which (this is a possible option) can accumulate during the dissipation into outer space of hydro gen formed during water decomposition. The specific process or processes of hematite formation require fur ther study. It is very likely that impact processing of polar regolith also leads to hydration of silicate glasses and to the formation of heavy hydrocarbons. The dissipation of free hydrogen into outer space, which, apparently, is formed in these processes, should lead to an increase in the deuterium content in the remaining hydrogen. The Н2О ice of the polar regolith likely contains a significant amount of heavy water. Future inves tigations in the polar regions of the Moon, especially with the delivery of samples to Earth, should confirm or refute these conclusions and assumptions.
Formation of a Plasma Layer During the Passage of the Moon through the Magnetic Ropes of the Solar Wind
Authors: Nabatov A. S. , Zakharov A. I. , Efimov A. I.
Published: April 2024

In the absence of a dense atmosphere and a general magnetic field around the Moon, solar wind particles reach the lunar surface and are almost completely absorbed. When the Moon passes through the plasma medium of the solar wind magnetic ropes, the electric currents of the rope can strongly change the electric potential of the lunar surface on the day and night surfaces, and in the case when the current density vectors of the rope and the direction to the Sun are close to colinear, there is the possibility of sufficiently strong ring currents, the magnetic field of which tends to displace the magnetic field of the rope and lead to the formation of a plasma layer with a height of the order of the electron Larmor radius.
Spectrophotometry and Other Remote-Sensing Methods to Study Asteroids: Achievements and New Approaches
Authors: Busarev V. V.
Published: April 2024

Physical parameters and characteristics of asteroids as solid atmosphereless celestial bodies are traditionally studied with the same methods as those used for investigating most of the other celestial objects, though they have certain specific features. The main attention is paid to spectrophotometry, as the most effective tool to study remotely the composition, evolution, and origin of asteroids. However, very important information about asteroids was also obtained by other observational methods, such as photometry, polarimetry, radiometry, and radar. Because of this, in addition to spectrophotometry, we discuss here photometry, polarimetry, and radiometry, which, on the one hand, are very close in methodology and, on the other hand, there has been a trend to their integrated use. In connection with the discovery of sublimation–dust activity on a number of asteroids and the periodic formation of a dust exosphere around these asteroids near perihe lion (see, e.g., Busarev et al., 2021), we also consider a methodologically new approach to estimating the chemical and mineralogical composition of particles in the exosphere of these asteroids and, indirectly, of their surface material.
Analytical Approximations of the Characteristics of Nighttime Hydroxyl on Mars and Intra-Annual Variations
Authors: Shaposhnikov D. S. , Grigalashvili M. , Medvedev A. S. , Zonnemann G. R. , Khartog P.
Published: April 2024

Observations of vibrationally excited hydroxyl (OH*) emissions are widely used to obtain information about the dynamics and composition of the atmosphere. We present some analytical approximations for the characteristics of the hydroxyl layer in the Martian atmosphere such as OH* concentration at the maximum and height of the maximum, as well as relations for estimating the influence of various factors on the OH* layer in night conditions. These characteristics depend on the temperature of the environment, concentration of atomic oxygen, and their vertical gradients. The relations are applied to the results of numerical modeling using the global atmospheric circulation model for prediction of seasonal behavior of the hydroxyl layer on Mars. Annual and intra-annual variations in the concentration of excited hydroxyl and layer height from the modeling data have both some similarities with those of the Earth and significant differences. The concentration and height maximum in the equatorial, northern and southern midlatitudes vary depending on the season; the maximum concentration and the minimum height fall on the first half of the year. Model calculations confirmed the presence of the peak OH* concentration at polar latitudes in winter at an altitude of approximately 50 km with the volume emission densities of 2.1, 1.4, and 0.6 × 104 photons cm–3 s–1 for vibrational level transitions 1–0, 2–1, and 2–0, respectively. The relations obtained may be used for the analysis of measurements and interpretation of their variations.
On the Kinetic Features of Sedimentation of Dust Particles in the Martian Atmosphere
Authors: Dubinsky A. Yu. , Reznichenkob Yu. S. , Popel S. I.
Published: April 2024

The mode of subsidence of layered structures in the ionosphere of Mars has been studied taking into account the compositional features of the Martian atmosphere. The characteristic sedimentation rates of dust particles, their sizes and charges, as well as the sedimentation time of layered structures are calculated. The results obtained can be used in the study of atmospheric phenomena on Mars in the course of upcoming space missions.
Negative Polarization of Celestial Bodies: Review and Computer Simulation
Authors: Petrov D. V. , Kiselev N. N. , Savushkin A. A. , Zhuzhulina E. A.
Published: April 2024

A brief review of the main causes of a negative degree of linear polarization of radiation scattered by regolith surfaces of atmosphereless cosmic bodies and ensembles of particles in the opposition region is presented. The results of computer simulation are provided, which made it possible to calculate the polariza tion degree of light scattered by pairs of irregular particles. The distance between the particles changed, which made it possible to obtain a visual representation of the total effect of the nature of negative polarization in the case of two-particle scattering (scattering in which two particles participate). Previously, a similar study was carried out for the case of two spherical particles, and showed that two-particle scattering by spheres only changes the degree of linear polarization in absolute value. We showed that two-particle scattering by irregular particles has a variable effect on the degree of linear polarization, both increasing and decreasing it. We also demonstrated that two-particle scattering by irregular particles can form a negative polarization even if the light scattered by a single particle is positively polarized. Therefore, in theoretical studies of the appearance of negative polarization, it is important to take into account two-particle scattering.
Features of Foreshock Transients at Planetary Bow Shocks
Authors: Shuvalov S. D.
Published: April 2024

In front of the bow shock with a quasi-parallel configuration of the interplanetary magnetic field, there exists a region called a foreshock, in which many nonstationary processes take place, the largest of which are collectively named “foreshock transients.” The size of these formations can reach tens of Earth radii, which significantly influences the nature of the solar wind interaction with the magnetosphere. Some types of foreshock transients are also observed at other planets, including those without their own global mag netic field, which indicates the universality of these phenomena. This article lists the most well-known non stationary processes occurring in the foreshock, as well as provides current ideas about the formation mech anisms of the largest foreshock transient.
Jeans Instability of an Astrophysical Self-Gravitating Medium in the Presence of High Radiation Pressure and Diffuse Radiative Transfer
Authors: Kolesnichenko A. V.
Published: April 2024

Within the problem of modeling the evolution of a protostellar disk, a discussion is presented on the effect of radiation on the Jeans gravitational instability for a self-gravitating optically thick (for intrinsic infrared radiation) gas-and-dust medium, taking into account the influence of radiation pressure perturbations and radiative diffusion transfer on the critical wavelength. Two radiative diffusion approximations are considered: the case of perfect thermal equilibrium with the same temperature of matter and radiation and the case of the time dependence of the radiation field with an energy separation between radiation and matter. An analysis of the normal regime of modes is used to derive dispersion relations, which enable the derivation of modifications of the classical Jeans instability criterion under the influence of radiation pressure and radiation diffusion. In particular, it is shown that, in contrast to the system’s local thermodynamic equilibrium, where the acoustic velocity of perturbed gas propagates with the isothermal speed of sound, in the case of different temperatures of radiation and gas, the perturbing wave propagates with the adiabatic speed of sound in gas. The results obtained are aimed at solving the problem of gravitational instability of individual massive protostellar disks or self-gravitating radiative media characterized by large optical depths for their dust-transformed intrinsic infrared radiation.
Searching for Life on Venus: History of the Problem and Basic Concepts
Authors: Kotsyurbenko O. R.
Published: April 2024

Venus has always been one of the priorities of the space research program in Russia. The history of successful investigations of Venus in the Soviet Union is primarily associated with delivering a whole series of spacecraft to it and implementing the first ever landing on its surface. In the last few years, the study of Venus in astrobiological direction has been rapidly developing. To date, a fairly large number of theoretical papers have been published, the main purpose of which is to estimate the possibility of the existence of living organisms on Venus. The most likely ecosystem, in which Earth-type organisms could develop, is considered to be a dense cloud layer of Venus. It is supposed that, in this layer, hypothetical microbial communities could exist in aerosols being a concentrated aqueous solution of sulfuric acid. Microorganisms in such a specific air habitat are to be exposed to several extreme factors at once, the main among which are very low values of pH and water activity. The principal strategies for survival under these conditions should be the availability of effective biochemical mechanisms of resistance to the impact of adverse environmental factors and the use of all possible ways of extracting energy in such an ecosystem to maintain the biomass of organisms at a level for stable reproduction.
Ground Testing of the Landing Platform Television System of the Exomars-2022 Spacecraft
Authors: Abramov N. F. , Polyanskii I. V. , Prokhorova S. A. , El’yashev Ya. D.
Published: April 2024

Ground testing results are presented for the landing platform television system (TSPP) within the complex of scientific payloads onboard the ExoMars-2022 spacecraft. In the course of the ground testing, the different operation modes have been checked and the camera characteristics have been measured and calibrated. The Space Research Institute (IKI RAS) has obtained photographic material from each camera, with the cameras being installed on a stand that simulates in full scale the ExoMars-2022 landing platform. In addition, special measurements have been collected for the cameras’ most important characteristics: horizontal and vertical angular field of view, distortion, focal length, resolution, dynamic range, vignetting coefficient, and absolute sensitivity.
Internal Structure of Venus Based on the PREM Model
Authors: Amorim D.O. , Gudkova T. V.
Published: April 2024

Models of the internal structure of Venus have been constructed with a wide range of crustal thickness (30–70 km) and core radius (2800–3500 km). An analysis of the pressure values in the center of the planet allows us to conclude that the presence of a solid inner core is unlikely if the composition and temperature profile of Venus correspond to that of the Earth. Andrade’s rheology was used to take into account the inelasticity of the interior of Venus when calculating the tidal Love numbers and the angle of delay of the tidal hump. Comparison of experimental values of the Love number k2 with the model gives the radius of the core of Venus in the range of 3100–3500 km. It is shown that to determine the characteristic viscosity of the Venusian mantle, the key factor is the determination of the angle of retardation of the tidal bulge: values of 0.9° correspond to low viscosity and high temperature, and 0.4° to high viscosity and low temperature, so the planned measurements of tidal parameters and the moment of inertia of the planet in the VERITAS and EnVision missions will be able to impose restrictions on the distribution of viscosity and temperature in the interior of Venus.
Native Nickel–Iron Metals from Lonar Crater Impactites (India) and Regolith of the Moon
Authors: Gornostaeva T. A. , Kartashov P. M. , Mokhov A. V. , Rybchuk A. P. , Basilevsky A. T.
Published: April 2024

The Lonar crater (India) is the best preserved and most studied on Earth, formed in basalts, which makes it possible to conduct a comparative study with impact transformations of mineral matter on the Moon and other planets of the Solar System. Comparative studies have shown that impactor material, both on the Earth and on the Moon, is present in impactites not only in a geochemically dispersed form, as previously thought, but also in the form of individual submicron particles distributed in the molten target material. These are particles of native nickel, taenite, and high-nickel kamacite, which, apparently, are the transformed material of the impactor. High-nickel submicron metal inclusions are widespread in the impactites of the Lonar crater, as they were found in all studied preparations made from materials collected from different points along the rim of the crater. The high-nickel particles found in this study are an additional argument in favor of the previously stated assumption about the chondrite type of impactor.
Determination of the Motion Parameters of Near-Earth Objects from Position Measurements Performed at the Terskol Observatory
Authors: Levkina P. A. , Chuvashov I. N.
Published: April 2024

The paper presents a method for processing positional observations of near-Earth objects using a numerical model of satellite motion developed at the Research Institute of Applied Mathematics and Mechanics of Tomsk State University (NII PMM TSU). The root-mean-square error of orbit improvement without rejection of observations for such objects does not exceed 0.3″ over a seven-day time interval. The results of the presentation of observations for the next occurrence of the object are obtained, which makes it possible to find the object in a time interval of five months. The orbit has been refined in the joint processing of measurements on several occurrences of the object over a six-month time interval. All results were obtained from observations made on the equipment of the Terskol Observatory Shared Use Center.
Temperature and Pressure Sensors of the Meteorological Complex for the Study of the Mars’s Atmosphere
Authors: Lipatov A. N. , Ekonomov A. P. , Makarov V. S. , Lesnykh V. A. , Goretov V. A. , Zakharkin G. V. , Zaitsev M. A. , Khlyustova L. I. , Antonenko S. A.
Published: April 2024

Temperature and pressure sensors, which are part of the ExoMars-2022 landing platform (LP) meteorological complex, are designed to measure the main parameters of the Martian atmosphere: temperature, pressure, and vertical component of wind speed. Temperature and pressure measurements begin during the descent, after the separation of the lower hemisphere, when the height above the surface will be from 2.1 to 8.5 km, depending on the descent trajectory. Above, before opening the parachute, the vertical profile of the atmosphere can be obtained using the accelerometer block, which is also part of the meteorological complex. After landing, a long-term monitoring of the near-surface layer of the atmosphere is carried out. Measurements are taken at different heights from the surface. Taking into account the measurement of the vertical component of the wind after landing, the local surface-to-atmosphere heat flux is calculated. The measurements make it possible to obtain the dynamics of the interaction between the atmosphere and the surface. In the paper we considered the scientific problems solved by the sensors, briefly described the measurement program and described in detail the sensors and their characteristics
Search for Signs of Sublimation-Driven Dust Activity of Primitive-Type Asteroids Near Perihelion
Authors: Busarev V. V. , Petrova E. V. , Shcherbina M. P. , Kuznetsov S. Yu. , Burlak M. A. , Ikonnikova N. P. , Savelova A. A. , Belinskii A. A.
Published: April 2024

In December 2021 to February 2022, the UBVRI photometry of 29 primitive-type asteroids of the Main Belt, being near the perihelion distances, was carried out at the 0.6-meter RC600 semiautomatic telescope of the Caucasus Mountain Observatory (CMO) of the Sternberg Astronomical Institute, Moscow State University. These observations, as well as the data processing and analysis, were aimed at searching for supposed sublimation-driven dust activity on asteroids under maximal subsolar temperatures. Among the tasks to be accomplished was the comparison of the physical and dynamic parameters of active and inactive asteroids. The main result is that substantial spectral signs of quasi-simultaneous sublimation-driven dust activity were detected on six primitive-type asteroids of the Main Belt—145 Adeona, 302 Clarissa, 322 Phaeo, 435 Ella, 690 Wratislavia, and 779 Nina (on 302 Clarissa, 322 Phaeo, 435 Ella, and 690 Wratislavia—for the first time). These six asteroids represent ~21% of all bodies included in the observation program. Probable spectral manifestations of activity at a lower intensity level were detected for the first time on five more asteroids— 424 Gratia, 751 Faina, 762 Pulcova, 778 Theobalda, and 859 Bouzaréah. On 145 Adeona and 779 Nina, sublimation-driven dust activity near perihelion was registered for the third time for the last ten years; this time interval corresponds to about three orbital periods of these asteroids around the Sun. We consider the circumstances due to which five of the listed asteroids possess families. General processes and conditions that could and/or can influence the portion of primitive-type asteroids that quasi-simultaneously show signs of sublimation-driven dust activity are discussed.
Internal Structure of the Lunar Mantle: Matching of Geochemical and Geophysical Models
Authors: Kuskov O. L. , Kronrod E. V. , Kronrod V. A.
Published: April 2024

There are serious contradictions between the geophysical and geochemical classes of models of the chemical composition and internal structure of the Moon, associated with the assessment of the abundance of the main oxides. The search for a potential consensus between the models was carried out on the basis of a set of geophysical and geochemical data using the Monte-Carlo method using the Markov chain scheme in combination with a method of minimization of the Gibbs free energy. The influence of the chemical composition and mineralogy of several conceptual models on the internal structure of the Moon has been studied. Two classes of chemical composition models are considered—the E models with terrestrial values of Al2O3 and CaO and M models with their higher content, as well as two classes of the most popular geochemical models, the Taylor Whole Moon (TWM) and Lunar Primitive Upper Mantle (LPUM) models, with ~45 wt % SiO2, but with different concentrations of refractory oxides and FeO. In both classes of E and M models, the lunar mantle is enriched in silica (~50 wt % SiO2) and FeO (11–13 wt %, Mg# 79–81) relative to the bulk composition of the silicate Earth (BSE, ~45 wt % SiO2, ~8 wt % FeO, Mg# 89). Such high concentrations of SiO2 and FeO become the determining factors for understanding the features of the mineral, velocity, and density structure of the lunar mantle. For the E and M models and geochemical models TWM and LPUM, the speed of sound and the density of stable phase associations are calculated. For E and M models, good agreement was obtained between the velocities of P- and S-waves and seismic sounding data from the Apollo program, which supports the idea of a silica-rich (olivine-pyroxenite) upper mantle. Unlike the Earth’s upper mantle, the dominant mineral in the Moon’s upper mantle is low-calcium orthopyroxene, not olivine. In contrast, the sound velocities of silica-unsaturated compositions, both FeO and Al2O3 enriched (TWM) and depleted (LPUM) models, do not match the seismic signatures. Thermodynamically justified restrictions on the chemical composition, mineralogy, and physical characteristics of the mantle based on the E and M models make it possible to eliminate some contradictions between the geochemical and geophysical classes of models of the internal structure of the Moon. Simultaneous enrichment in ferrous iron and silica is difficult to reconcile with the hypothesis of the formation of the Moon as a result of a giant impact from the substance of the Earth’s primitive mantle or from the substance of a shock body (bodies) of chondrite composition. Limitations on lunar concentrations of FeO and SiO2 probably correspond to the parent bodies of some achondrites.
Jeans Gravitational Instability of a Rotating Collisionless Magnetized Plasma with Anisotropic Pressure
Authors: Kolesnichenko A. V.
Published: April 2024

The problem of self-gravitational instability of an astrophysical rotating plasma in a strong magnetic field with an anisotropic pressure tensor is studied on the basis of the Chew–Goldberger–Low (CGL) quasi-hydrodynamic equations modified by generalized polytropic laws. Using the general form of a dispersion relation obtained by the normal-mode perturbation method, a discussion is provided of the propagation of small-amplitude perturbation waves in an infinite homogeneous plasma medium for transverse, longitudinal, and oblique directions with respect to the magnetic field vector. It is shown that different polytropic indices and anisotropic pressures not only change the classical Jeans instability condition but also cause the appearance of new unstable regions. Modified Jeans instability criteria are obtained for isotropic MHD equations and anisotropic CGL equations owing to the influence of the polytropic indices on gravitational and firehose instabilities for astrophysical plasma. It is shown that in the case of a longitudinal mode of perturbation wave propagation, the Jeans instability criterion does not depend on uniform rotation. In the case of the transverse propagation regime, the presence of rotation reduces the critical wave number and exerts a stabilizing effect on the growth rate of the unstable regime.
Thermal Sounding of the Martian Atmosphere Using the ACS TIRVIM FT-IR Spectrometer on Board ExoMars TGO: Method for Solving the Inverse Problem
Authors: Vlasov P. V. , Ignatiev N. I. , Korablev O. I. , Fedorova A. A. , Grigoriev A. V. , Patsaev D. V. , Maslov I. A. , Shakun A. V. , Guerlet S. , Grassi D. , Zasova L. V.
Published: April 2024

This paper presents a method for solving the inverse problem of thermal sounding using calibrated data from the ACS TIRVIM experiment on board the ExoMars Trace Gas Orbiter. The 1.7–17 µm range TIRVIM Fourier spectrometer as part of the ACS instrument complex aboard the ExoMars TGO operates in the nadir and solar occultation modes in orbit around Mars. The main scientific goal of TIRVIM in the nadir observation mode is the long-term constant monitoring of the thermal structure of the Martian atmosphere and the general content of aerosols and water vapor from measurements in the range of 5–16.7 µm (600–2000 cm–1). To process the TIRVIM nadir measurements, an algorithm was developed, allowing the retrieval of the vertical temperature profile from the surface to 60 km, the surface temperature, and the general content of dust and water ice in the atmosphere from the TIRVIM spectrum in the range of 600–1250 cm–1, as well as the water vapor column abundance according to measurements in the range of 1250–1830 cm–1. The processing method widely uses the achievements of previous similar experiments, taking into account the features of the TIRVIM spectra. Using the developed method 2.28 × 106 spectra obtained by TIRVIM in nadir by regular measurements, were processed with retrieval of the thermal structure up to 60 km altitude and the aerosol content in the atmosphere as well as additional 2.3 × 105 specially averaged TIRVIM spectra, were processed with retrieval of the water vapor column abundancein the Martian atmosphere.
ASSESSMENT AND PROTECTION OF GEOENVIRONMENT COMPONENTS FROM IMPACTS PRODUCED BY TECHNOGENOUS HYDROCARBON DEPOSITS
Authors: Chertes K. L. , Tupitsyna O. V. , Petrenko E. N.
Published: April 2024

The article presents the results of studies of technogenous hydrocarbon deposits - Light Non-Aqueous Phase Liquid (LNAPL) bodies in technonatural systems. The specific feature of these bodies is their location in the geological environment beneath operating and abandoned oil industry enterprises. Enterprises are the sources of hydrocarbons in the geological environment. Light non-aqueous phase liquid bodies are interpreted as complex, dynamic, multicomponent systems, which are subject to the influence of flooding and low-water phenomena in the nearby surface water bodies. Based on the study of archive data and the results of field survey of these objects, the integrated system has been developed for assessing the status of technonatural systems containing LNAPL bodies. It is based on the suggested criteria, and includes geometric, technological, geoecological, resource-economic and inertial-oscillatory groups. The scheme of carrying out a complex of works, including research, assessment, modeling, and liquidation of LNAPL bodies is proposed. This scheme takes into account the LNAPL dual nature: on the one hand, LNAPL body contaminate the environment, on the other hand, produce secondary hydrocarbon resources. The proposed integrated assessment system permits us to determine the current state of LNAPL bodies as a part of technonatural systems, to select and justify technological solutions for their liquidation and remediation of contaminated sites.
COMPARISON OF THREE APPROACHES TO CALCULATING DIAMETER OF A DROPOUT SINKHOLE
Authors: Khomenko V. P. , Leonenko M. V. , Dzutsev A. O.
Published: April 2024

The possibility of sinkhole size prediction in the areas, where soluble rocks are covered by impermeable clay layer is considered. Such sinkholes are named by English-speaking authors as “dropout sinkholes” or “cover collapse sinkholes”, because the process of their formation includes collapse (dropping) of clay covering soluble rocks into a karst cavity. Triggers of this effect are: (1) widening of a cavity below the clay due to dissolution of a soluble rock by groundwater; (2) lowering of hydraulic head in confined karst aquifer, primarily caused by groundwater pumping, which results in decreased support of the overlying clay layer; (3) a dynamic load on the clays, which can have either natural or man-made origin. Fresh dropout sinkholes generally have configuration similar to vertical right circular cylinder, but sometimes their shape can be dome-like with very unstable ground “cantilevers”. The appearance of these forms under foundations can lead to deformation and even to destruction of buildings, structures, and infrastructure facilities. Two concepts exist, which can be used as basis for creating models of soil mechanics to calculate diameter of a dropout sinkhole. The first one is based on a viewpoint that clay collapse into a cavity after a trigger action is displayed immediately at the ground surface as a collapse sink. According to the second concept, the preliminary subsurface collapse of clay occurs as fall of ground block resembling a circular paraboloid. As a result, a dome-like cavity appears in the clay layer and above-lying clay fall into it to form a collapse sink. There are no prediction methods based on the two above-mentioned conceptions. The developed approaches to prediction of a dropout sinkhole diameter are adequately comparable, as they use the same input calculation parameters. The prediction results based on these approaches have been compared to an actual diameter of fresh dropout sinkhole. This verification have allowed us to infer that most adequate is the approach based on concept of initial subsurface clay’s collapse preceding the final collapse sink formation.
EXPERIENCE IN GEOSTRUCTURAL AND GEODYNAMIC INVESTIGATIONS OF NUCLEAR POWER PLANT ALLOCATION TERRITORIES FOR ASSESSING STABILITY OF ENGINEERING STRUCTURES
Authors: Makarova N. V. , Makeev V. M. , Sukhanova T. V. , Miklyaev P. S.
Published: April 2024

The results of geological and structural-geodynamic research are presented for the territories of several nuclear power plants (NPP) located on the East European Platform. The influence of geological structure, lithology, and the latest tectonic movements are considered as well as the resultant structures and relief, which generally represent the geological environment, on the stability of the NPP areas. Structural and geodynamic conditions, in particular, recent tensile stresses that cause intense rock fracturing and high gas-fluid permeability, suffusion, karst and landslide, are proved to be the main causes of hazardous processes resulting in settling and tilting of some NPP buildings. Tectonic sloping of the sites towards descending depressions, the sand basement of NPP sites, sloping clay aquicludes, fluctuating water levels in the adjacent water reservoirs, the presence of so-called “hydrogeological windows”, the buried relief and modern structural and geodynamic conditions, i.e., tectonic stresses (tensile stresses in many cases) contribute to building deformations. Along with solving practical problems, a number of theoretical issues are considered. Lineaments are associated with rock fracture zones and faults zones; the fault zones in crystalline foundation influence the formation of recent structures; and new platform structures, i.e. gravity-tectonic massifs and pull-apart depressions, are distinguished.
LEACHING OF CONTAMINANTS FROM BURIED PRODUCTS OF MECHANICAL-BIOLOGICAL WASTE TREATMENT IN LARGE-SCALE EXPERIMENTS
Authors: Yuganova T. I.
Published: April 2024

Large-scale experiments on the leaching of pollutants from the products of mechanical and biological treatment of municipal solid waste (MSW) simulating the disposal at a real landfill are considered. These are studies in large reactors and in the experimental section of the MSW landfill, where stabilized waste is placed. The results of these experiments are described and compared with those obtained in the course of various laboratory tests. Recommendations are given for improving laboratory tests and predictive models.
Influence of Crystal Structure on the Set of Physicomechanical Characteristics of Composite Materials Based on Ultra-High Molecular Weight Polyethylene
Authors: Zabolotnov A. S. , Gostev S. S. , Maklakova I. A. , Bakirov A. V. , Novokshonova L. A. , Kiyasov A. A.
Published: April 2024

Composite fibers containing boron(III) have been obtained based on solid solutions of cellulose in N-methylmorpholine-N-oxide and orthoboric acid with their subsequent transformation into a viscous-flow state. The rheological behavior of cellulose solutions with different content of orthoboric acid and water studied under conditions of continuous and dynamic shear loading has confirmed the intermolecular interaction between the components. It has been shown that the mechanical characteristics of the composite fibers obtained from a 16% solution in N-methylmorpholine-N-oxide are comparable to these for hydrated cellulose fibers. The process of transformation of the composite fibers of various compositions into carbon fiber has been investigated by means of thermogravimetric analysis and differential scanning calorimetry. Chemical, structural and morphological properties of composite hydrated cellulose fibers and carbon fibers obtained from them have been studied using FTIR-spectroscopy, X-ray diffraction, and scanning electron microscopy. The influence of boron(III) compounds on the carbonization process and the formation of graphite-like structures in carbon fiber has been investigated by Raman-spectroscopy.
Reactivity of New Monomers of the Polyurethanes Green Chemistry, the Reaction Mechanism, and the Medium Effect
Authors: Zabalov M. V. , Levina M. A. , Krasheninnikov V. G. , Tiger R. P.
Published: April 2024

The influence of the substituents inductive effect and the proton-donor OH group in the substituted cyclocarbonates differing in the alkyl chain length on the activation barrier of their aminolysis reaction, which underlies the process of urethane formation without the participation of isocyanates, has been studied. Account for the solvent molecules has allowed quantitative interpretation of the process regularities. Kinetics of the model aminolysis reaction of a series of monomers in DMSO has been investigated.
Graft Polymerization of 5-Vinyltetrazole onto Chitosan
Authors: Kizhnyaev V. N. , Balakhovtsev I. D. , Penzik M. V. , Pokatilov F. A. , Edel’shtein O. A.
Published: April 2024

Polymerization of 5-vinyltetrazole under conditions of radical initiation in aqueous media in the presence of chitosan gave network graft copolymers, the structure of which is built from chitosan macromolecules crosslinked by chain fragments of poly(5-vinyltetrazole). It was determined that the polymerization is preceded by the formation of a saltlike product between chitosan macromolecules and vinyl monomer, which affects its polymerization activity. The obtained graft copolymers are prone to limited swelling in water to form pH-sensitive ampholytic hydrogels.
Neutral Red and Safranin Т in the Photopolymerization of Methyl Methacrylate and Other (Meth)Acrylate Monomers
Authors: Lizyakina O. S. , Vaganova L. B. , Grishin D. F.
Published: April 2024

Features of the polymerization of methyl methacrylate and a number of other (meth)acrylate monomers in the presence of catalytic systems based on phenazine dyes (Neutral Red and Safranin Т) under visible light irradiation are investigated. It is shown that amines of various structure as well as air oxygen affect the kinetic features of polymerization and the molecular weight characteristics of polymers. It is found that polymerization may proceed in the controlled mode up to high conversions at room temperature and a low photocatalyst concentration, among them without preliminary degassing of the reaction medium.
Synthesis of Composite Polymer Particles by Seeded Emulsion Polymerization and Formation of Photonic Crystals Based on Them
Authors: Iakobson O. D. , Ivan’kova E. M. , Vaganov G. V. , Krasnopeeva E. L. , Shevchenko N. N.
Published: April 2024

Submicron composite particles with the core/shell structure are synthesized by the seeded emulsion polymerization of a mixture of various acrylates in the presence of a redox initiation system. The diameter, morphology, and surface structure of particles as well as their ability to self-assemble into 3D ordered thin-film structures are studied by scanning electron microscopy, FTIR spectroscopy, thermogravimetry, and dynamic light scattering. It is shown that under the used experimental conditions particles with a shell thickness of 10‒35 nm are synthesized. The effect of shell composition (in particular, the alkyl chain length of acrylate comonomers) on the morphology and structure of the surface layer of the obtained composite particles is traced.
Geometric Features of Structuring of Amphiphilic Macromolecules on the Surface of a Spherical Nanoparticle
Authors: Mitkovskiy D. A. , Lazutin A. A. , Ushakova A. S. , Talis A. L. , Vasilevskaya V. V.
Published: April 2024

The self-assembly of amphiphilic homopolymers tightly grafted to the spherical nanoparticle and immersed in a selective solvent is studied by the computer experiment method. Conditions under which macromolecules form thin membrane-like layers surrounding the nanoparticle are determined. It is first shown that the emerging polymer structures may be approximated by complete embedded minimal surfaces satisfying the Weierstrass representation, namely, helicoid, catenoid, and Enneper and Costa surfaces. Mathematical constructions defining these minimal surfaces highlight a new type of ordering of polymer structures and determine its symmetry classification similar to crystal classification by Fedorov groups. Calculations for the two considered sets of parameters show that structures approximated by a helicoid are energetically more favorable than structures approximated by other minimal surfaces.
In Memoriam of I. Ya. Erukhimovich
Authors: Hohlov A. R , Vasilevskaya V. V.
Published: April 2024

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Elasticity of Highly Entangled Polymer Networks and Gels: Review of Models and Theory of Nonaffine Deformations
Authors: Panyukov S. V.
Published: April 2024

The main models of phantom and topologically entangled polymer networks are surveyed. A theory of anisotropic and nonaffine deformation of both swollen and deswollen (with partial solvent removal) strongly entangled polymer networks in athermal and θ-solvents has been developed. It is shown that under weak anisotropic deformations of the deswollen network, the entanglement tube consists of fractal loopy globules. In a θ-solvent, slight deformations of the network lead to a decrease in the overlap of loopy globules without changing their sizes. Deformations of swollen networks, as well as strong deformations of deswollen networks, are described in terms of the slip-tube model. An effective Hamiltonian has been derived that determines the entropy of fractal loopy globules. Based on the Hamiltonian, it is shown that topological constraints can be described using the polymer–quantum diffusion analogy. The connection between topological and quantum entanglements is demonstrated.
The Rheological Behavior of Polymer Solution Threads
Authors: Subbotin A. V. , Nyrkova I. A. , Semenov A. N.
Published: April 2024

Theoretical results of the authors in the field of the capillary thinning of polymer solution threads are reviewed. The dynamics of threads of both concentrated solutions without entanglements and dilute solutions, where hydrodynamic interactions play an important role, is considered. A molecular approach, in which macromolecules are simulated by a semiflexible chain, is used as a basis. This makes it possible to describe, from common positions, the nonlinear elasticity of solution and interactions taking into account the orientation of the chains. Particular attention is given to thread thinning in the region of the elastic behavior of solution where macromolecules unfold along the axis of stretching. The results of analysis of the capillary stability of a thread and conditions for solvent droplets emergence on its surface are presented, and the dynamics of formation of the hierarchical structure of beads-on-string droplets is viewed. Mechanisms behind the subsequent merging of droplets related to solvent overflow and droplets diffusion along the polymer string are discussed. The polymer string breakup occurs at time scales higher than the Rouse relaxation time of the polymer chain. String hardening and fiber formation may be an alternative.
Evolution of Organometallasiloxanes
Authors: Anisimov A. A. , Minyaylo E. O. , Shakirova A. R. , Shchegolikhina O. I.
Published: April 2024

The development of organometallasiloxane chemistry from first polymeric systems to individual organometallasiloxanes and functional oligomeric compounds is considered. The structural diversity of organosilicon precursors and the variability of metal-containing components are presented. Synthetic approaches are considered in detail, including those that allow targeted production of organometallasiloxanes of a certain structure. Using the example of organometallasiloxanes synthesized from trifunctional organoalkoxysilanes, methods for the synthesis of unique stereoregular functional cyclosiloxanes and their derivatives are highlighted. Considerable attention is given to the applied aspects of various structure organometallasiloxanes and their derivatives. The state of the art of the chemistry of organometallasiloxanes and their further evolution are evaluated critically.