bluuebunny/crossref_metadata_2025 huggingface dataset:
Weak Seismicity and Strongest Earthquakes Against the Background of the Variations of S-wave Attenuation Field
Authors: Aptikaeva O. I.
Published: April 2024

The paper considers the role of relatively weak earthquakes as a tool for studying the environment, including of strong earthquake process. The spatial structure of the attenuation field of several seismically active regions (of the Garm prognostic polygon in Tajikistan, Altai, the Caucasus, Eastern Anatolia, the Western Tien Shan), as well as the epicentral regions of a number of strong earthquakes, and the confinement of deepened seismicity to it are considered. It is shown that the attenuation field obtained from the short-period code of weak earthquakes in seismically active regions is inhomogeneous and consists of blocks with a high Q factor and weakened zones of strong attenuation. An uneven distribution of deepened earthquakes is noted. It is associated with the block structure: in weakened zones, their share is greater than in blocks with a high Q factor. Examples of variations in the of deepened seismic activity in weakened zones are demonstrated. It varies over time, increasing before strong earthquakes. Facts are presented that testify to the existence of a relationship between the Earth’s rotation rate and the activity of deepened seismicity. Examples are given of the activation of weak seismicity in the form of seismic swarms (series of weak earthquakes concentrated in space and time) in connection with strong events. A characteristic feature of these swarm series is the isometry of the earthquake localization areas in plan view and vertical elongation. As a rule, they coincide with weakened zones of strong absorption of S-waves. Intense localized seismicity, confined to one-dimensional volumes, is most likely associated with increased conductivity channels through which deep fluids migrate. The activation of swarm series is the result of active migration of deep fluids and an increase in fluid saturation of weakened zones. Fluids, in turn, are a catalyst for processes that lead to a decrease in the strength of rocks and the destruction of blocks in epicentral zones. In this case, the clusters to which the swarm series belong can be considered as local seismogenic zones. The appearance of compact isometric in plan and nearly vertical in section clusters of weak seismicity is often observed outside the epicentral zones of strong earthquakes. Such zones may simply be indicators of the seismotectonic situation in the region as a whole. It is assumed that a sharp change in the dynamics of atmospheric pressure during the preparation of a strong earthquake at hydrometeorological stations located in such areas is a consequence of the intergeospheric interaction of the lithosphere and atmosphere. Deep degassing seems to be one of the main mechanisms of the anomalous behavior of atmospheric pressure during the implementation of strong events. It is most active in weakened zones. The mechanisms of the impact of deep degassing on the outer geospheres remain the subject of discussion.
The Influence of Materials Structure on the Main Features of the Fracture Process in Rocks: Discrete Elements Method and Laboratory Experiment
Authors: Hilarov V. L. , Damaskinskaya E. E. , Gesin I. D.
Published: April 2024

A computer model of fracture of the heterogeneous materials (including rocks) based on the Discrete Element Method (DEM) is proposed. We used the bonded particle model (BPM), various modifications of which are widely used in the study the fracture process. The material is modeled by a set of spherical particles (simulating polycrystalline grains) connected by bonds placed at the points of particle contacts (simulating grain boundaries). In BPM model, the initiation of cracks was determined by the bonds breakage, and their propagation is provided by the coalescence of many broken bonds. Computer experiments were carried out for the materials with different features (various grain mechanical properties and sizes, various mechanical properties of the grain boundaries), in order to find out the influence of these parameters on local stresses and the defect formation. Calculations were held in the MUSEN software. Cylindrical samples were filled with spherical particles of the same or different radii. The parameters of materials for grains and bonds (grain boundaries) were taken corresponding to granite, quartz, orthoclase, oligoclase, and glass. The sample was placed in a virtual press, in which the lower plate was stationary, and the upper plate moved towards the lower one at a constant velocity until the sample was destroyed. The calculation of the maximum local stresses showed that the homogeneity of material leads to greater space heterogeneity of local stresses and vice versa, heterogeneity contributes to their greater uniformity. Comparison with the results of laboratory experiments on rock deformation showed that the proposed model of polycrystalline materials realistically describes some features of their destruction when the main processes occur along the grain boundaries. These features include the brittle nature of homogeneous materials fracture and the presence of nonlinear elasticity (plasticity) for ones that were more heterogeneous. For heterogeneous materials, the model demonstrates a two-stage character of fracture process, when at the first stage the accumulation of defects occurs uniformly over the sample, and at the second stage – the formation and growth of the fracture site.
The Influence of Mining Operations on Seismic Activity of the Rocks in Underground Mines of the Khibiny Massif
Authors: Kagan M. M. , Kozyrev A. A. , Motorin A. Yu. , Streshnev A. A.
Published: April 2024

The issues of the causes and factors of manifestation of seismic activity during the extraction of minerals in the deposits of the Khibiny massif, which are mined underground, are considered. Based on seismic monitoring data, groups of seismic activity were identified, such as seismicity in the working area, directly related to blasting and natural seismicity, related to other mining and geological factors. The difference in the characteristics of the manifestation of seismicity for these two groups of seismic events is shown.
Seismic Phenomena Associated with the Eruption of a Volcano in the Area of the Tonga Archipelago on January 15, 2022
Authors: Ovtchinnikov V. M. , Usoltseva O. A.
Published: April 2024

The study of changes in the seismic process associated with the eruption and the assessment of the energy parameters and structure of the wave field from seismic data is the subject of this work. Three types of disturbances are distinguished in the structure of the wave field. First of all, these are Rayleigh surface waves with an average oscillation period of 23 s, well traceable at distances up to 100 degrees. The group velocity of Rayleigh waves is 3.6–3.8 km/s. The magnitude calculated from them at stations mainly with oceanic propagation paths is Ms = 5.52 ± 0.18, and the corresponding seismic energy was on the order of Ec = (1–7) × 1013 J, and the scalar seismic moment M0 =2.4 × 1017 J. Two other types of oscillations were detected on seismic channels with a frequency band from 0.0003 to 0.1 Hz of the stations. For the first, the apparent velocity of propagation of the disturbance lies in the range of 0.28–0.37 km/s with a characteristic period of 268 s. This type of disturbance is associated with the gravitational response of the seismometer to an acoustic disturbance in the atmosphere. For the second type of seismic disturbances, the propagation velocity is 0.21–0.28 km/s with characteristic periods of 450 s on the horizontal components of seismic receivers. This type of seismic disturbance is probably caused by the interaction of the gravitational wave in the hydrosphere with the coast of the islands on which the seismic stations are located.
On the Difference in Physical Mechanisms of Different Depth Earthquakes and Their Ionospheric Response Patterns
Authors: Rodkin M. V. , Liperovskaya E. V.
Published: April 2024

According to the paradox of seismicity, earthquakes that follow the mechanism of ordinary brittle failure cannot occur at depths below a few tens of km. Several models have been proposed to explain deeper earthquakes, but these models have not been convincingly supported by data on the depth changes in earthquake source parameters. In this paper we present the examples of seismicity cutoff at the depth level of the Earth’s crust despite the undoubted continuation of similar shear displacements at greater depths. Based on worldwide data, the changes in a number of the average parameters of the earthquakes with depth are demonstrated. The pattern of these changes is consistent with expected differences in the physical mechanisms of the earthquakes with depth and significantly refines the accepted division of earthquakes into shallow, intermediate, and deep. The difference in the physical mechanisms of the earthquakes implies a probable difference in the nature of their precursors. Based on the hourly data of the vertical ionospheric sounding station “Tokyo” for 1957–2020, differences in the character of the seismoionospheric effect are demonstrated for the earthquakes (more than 300 events) occurring at different depths and presumably having different dominant mechanisms of seismogenesis. The average amplitude of the variations in the critical frequency foF2 providing the observed anomalies is estimated to be only 2–3% of the foF2 value. The separation of earthquakes by depth increased the statistical significance of the observed seismoionospheric effect.
Migration of Anomalous Displacements on the Flanks of a Preparing Earthquake Source: A Swing Model
Authors: Bondur V. G. , Garagash I. A. , Gokhberg M. B. , Alekseev D. A.
Published: April 2024

The geomechanical modeling results on the stress-strain state dynamics before the 2019 M = 7.1 Ridgecrest earthquake, Southern California, show the alternating development of maximum displacements at the fault’s ends, which simulates the process of “swinging” of the epicentral zone of the earthquake. These results together with the existing theoretical ideas about the block structure of the Earth’s crust and the corresponding connections between blocks are used to construct a geomechanical “swing” model based on the stick-slip motion of three interconnected blocks. The model parameters are related to the rheological properties of the Earth’s crust in the region of the rupture of the bridging isthmus which determines the source size of the seismic event.
Response of Sandy and Clayey Soils to Weak And Strong Seismic Loading
Authors: Deshcherevskaya E. V. , Pavlenko O. V.
Published: April 2024

The response of sandy and clayey near-surface soils representing the classes of noncohesive and cohesive soils to seismic loading of various intensities is analyzed from the in situ data —from the records by vertical groups of the Japanese nationwide KiK-net strong motion seismograph network. For the analysis, out of a total of ~800 stations, we selected five stations with near-surface sandy soils and five stations with near-surface clayey soils, most purely represented in the upper layers. Using the method (Pavlenko and Irikura, 2003), we have constructed and analyzed the models of strong ground motion behavior for “sandy” and “clayey” stations, showing the distributions of earthquake-induced stresses and strains in the soil layers. Close estimates of the amplification of seismic waves in sands and clays at weak seismic ground motion and close stress-strain relationships characterizing the behavior of the near-surface soils at moderate seismic ground motion are obtained. The liquefaction of sandy soils under strong shaking (the 2011 Tohoku earthquake with Мw ~ 9.0) is analyzed. The effects of the extended seismic sources (directivity of their radiation pattern) on the behavior of sandy and clayey soils and the amplification of seismic waves in these soils is studied. Differences in the behavior of sandy and clayey soils are noted only at strong seismic motions: liquefaction in sandy soils is possible if the groundwater level is on the order of a few meters from the surface, while in clayey soils there is no liquefaction.
ε-Fe Electrical Resistivity at High Pressures of Stepwise Shock Compression
Authors: Molodets A. M. , Golyshev A. A.
Published: April 2024

In situ electrical resistivity measurements are performed on samples of iron with a hexagonal close–packed lattice (ε–Fe), compressed and heated by stepwise shock loading. Equations of state for ε-Fe are constructed. The obtained experimental results are mathematically simulated in the hydrocode based on the developed equations of state. The modeling results are used to reconstruct the volumetric–temperature dependence of the ε–Fe electrical resistivity at pressures of ≈20–70 GPa and temperatures of ≈750–950 K. The volume–temperature dependence of the ε-Fe thermal conductivity coefficient is calculated according to the Wiedemann–Franz law. The results obtained for the electrical and thermal conductivity of shock compressed and heated ε-Fe are compared with literature experimental and theoretical data for iron and silicon iron.
Determination of the Effective Electrical Conductivity of a Fluid–Saturated Core from Computed Tomography Data
Authors: Epov M. I. , Shurina E. P. , Dobrolyubova D. V. , Kutishcheva A. Yu. , Markov S. I. , Shtabel’ N. V. , Shtan’ko E. I.
Published: April 2024

Abstract—This paper proposes a technique for determining the effective specific electrical conductivity of rock samples when their digital models are used. A modified algorithm for reconstructing the internal structure of the sample from the core’s nondestructive imaging data can be used to construct a relevant discrete model that approximates the pore space with a high degree of accuracy. Unlike existing approaches, the reconstructed discrete geometric model of a heterogeneous medium sample is hierarchical and oriented to the application of parallel computational schemes of multiscale finite element methods for a forward mathematical simulation of electromagnetic processes. The paper presents the results of solving the problem of determining the effective specific electrical conductivity of fluid–saturated rock samples and compares them with the data from laboratory experiments.
On the Magnetic Effects due to the Earthquake of March 16, 2022 in Japan
Authors: Nosikova N. S. , Pilipenko V. A. , Shalimov S. L.
Published: April 2024

Abstract—The magnetic effects of two similar underwater earthquakes with magnitudes of 6.0 and 7.3, which occurred on March 16, 2022, were considered in [Adushkin et al., 2023]. According to the data of INTERMAGNET magnetic observatories, these earthquakes were found to be accompanied (with a delay of ~55 min) by variations in the Earth’s magnetic field in the form of a train of quasi-periodic oscillations with an amplitude of ~2–8 nT and a period of ~30 min at distances of ~210 to ~3000 km from the epicenter. It was suggested in the aforementioned study that this magnetic effect is caused by a perturbation of the geodynamo as a result of the impact of seismic waves propagating deep into Earth. This interesting hypothesis requires a detailed discussion from different points of view. A more detailed analysis of the pattern of geomagnetic field perturbation at all latitudes, performed by us, leads to a conclusion that the found quasi-periodic perturbation is a mid-latitude response to auroral electrojet variations and is not related to the earthquake. According to our estimates, variations with a source at the core–mantle interface on a time scale less than 1 year cannot manifest themselves on the Earth’s surface at all.
Theory of Anhysteretic Remanent Magnetization of Single-Domain Grains
Authors: Shcherbakov V. P. , Sycheva N. K.
Published: April 2024

Abstract—A new approach to the solution of kinetic equations describing the process of formation of anhysteretic remanent magnetization (ARM) is proposed, which made it possible to accelerate the numerical calculation of the process of formation of ARM by two orders of magnitude for uniaxial oriented non-interacting single-domain particles, while practically not yielding in accuracy to a strict numerical solution. It follows from the calculation results that the susceptibility of ARM is entirely determined by the magnitude of the particle’s coercivity parameter. The data of the previous approximate calculations of ARM value are compared with the exact results presented here and it is shown that the discrepancy between the exact data and the approximate estimates increases with the growth of g, but remains relatively small, within 23%. The proposed algorithm for the rapid calculation of kinetic equations allows us to analyze with physical rigor the method of pseudo-Thellier estimation of paleointensivity for an ensemble of single-domain particles, which is supposed to be done in subsequent works.
Source Parameters of Strong Turkish Earthquakes on February 6, 2023 (Mw = 7.8 and Mw = 7.7) from Surface Wave Data
Authors: Filippova A. I. , Fomochkina A. S.
Published: April 2024

Abstract—Based on the amplitude spectra of surface waves, the source parameters of the strong Turkish earthquakes of February 6, 2023 (Mw = 7.8 and Mw = 7.7) were calculated in two approximations: an instantaneous point source and an elliptical shear dislocation. As a result, rupture planes were identified, data were obtained on the scalar seismic moment, moment magnitude, focal mechanism, and source depth of the considered seismic events, and the integral parameters characterizing the rupture geometry and its development in time were estimated. It is shown that the sources of the earthquakes under study were formed under the influence of the regional stress field and their focal mechanisms were left lateral faults with a strike direction close to the strike of the East Anatolian fault zone for the first event and close to the strike of the Sürgü-Çardak fault system for the second. For the first earthquake, our estimates of the rupture duration and its length (t = 52.5 s, L = 180 km) probably refer not to the entire rupture, but only to its main phase, confined to the northeastern segments of the East Anatolian fault and characterized by maximum displacements and values of the released seismic moment. The values of t = 30 s and L = 180 km that we obtained for the second earthquake fully characterize the entire rupture.
Rupture Directivity Effects of Large Seismic Sources, Case of February 6, 2023 Catastrophic Earthquakes in Turkey
Authors: Pavlenko O. V. , Pavlenko V. A.
Published: April 2024

Abstract—An overview of the results obtained by foreign seismologists based on the records of Turkish seismic networks AFAD (State Agency for Disaster Management under the Ministry of Internal Affairs) is presented. The sequence of earthquakes began with the M7.8 main shock and includes thousands of aftershocks. The strongest events occurred in the first twelve hours, with the sources of two M7.0+ events located 100 km apart. Earthquakes have caused ground motions that are destructive to structures, the so-called “pulse-like waveforms”, and epicentral distances, as was previously noted, are not a good indicator of attenuation of waves from earthquakes with extended ruptures. The records of stations in the near-fault zones clearly revealed the directivity effects of seismic radiation. The M7.8 earthquake (main shock) was larger than expected in the current tectonic setting. The near-field records traced an early transition to the super-shear (~1.55Vs) rupture propagation on the Narli lateral fault, where the rupture originated and then passed into the East Anatolian fault. The early transition to the super-shear stage obviously contributed to the further propagation of the rupture and the initiation of slips on the East Anatolian fault. A dynamic fracture model has been constructed that matches the various results of inversions obtained by different authors and reveals spatially inhomogeneous rupture propagation velocities. Super-shear velocities exceeding the shear wave velocity Vs are observed along the Narli lateral fault and at the southwestern end of the East Anatolian fault. Since the late 1990s, seismologists have been working on incorporating the rupture directivity effects of extended sources into the probabilistic seismic hazard analysis procedures, but no consensus has been reached so far, and progress in this area can only be expected with the accumulation of a sufficient amount of observational data.
Application of New Statistical Methods to Estimation of the Seismicity Field Parameters by an Example of the Japan Region
Authors: Pisarenko V. F. , Skorkina A. A. , Rukavishnikova T. A.
Published: April 2024

Abstract—This study is devoted to application of some new statistical methods to analysis of the spatial struc-ture of the seismic field in the seismically active region in the Japan region bounded by the following coordinates: 28°–50° north latitude, 130°–150° east longitude. The estimates of the seismic flux by using the k nearest neighbors method for the magnitude interval m ≥ 5.2. The highest values of intensity of about 10–4 \(\frac{1}{{{\text{year}}{\kern 1pt} - {\kern 1pt} {\text{k}}{{{\text{m}}}^{{\text{2}}}}}}\) are located at depths of down to 100 km and manifest themselves in the neighborhood of the Tohoku megathrust earthquake. The spatial resolution of the intensity estimates is ranging from 33–50 km in the regions with a high intensity to 100 км and larger in the zones of weak intensity. It has been shown that the seismic filed parameters – intensity λ, slope of the graph of repetition β, maximum possible magnitude m1 – have different scales of their spatial variability and, thus, it is necessary to apply different scales of spatial averaging to them. Based on the Gutenberg—Richter truncated distribution model, the estimates are obtained for the slope of the graph of repetition (b-value) and the upper boundary of the distribution m1. An original method is proposed for determining the optimal averaging radius for an arbitrary cell of the space grid. The method is based on the use of the statistical coefficient of variation of the corresponding parameter. For the considered region, the estimate of the maximum possible magnitude Мmax = 9.60 ± 0.41 was obtained with consideration of the correction for bias.
Response of the Lower and Upper Ionosphere to Earthquakes in Turkey on February 6, 2023
Authors: Riabova S. A. , Olshanskaya E. V. , Shalimov S. L.
Published: April 2024

Abstract—Ground-based magnetometers and ionospheric radio probing by means of GPS were used to analyze and interpret specific variations of the geomagnetic field and the total electron content of the ionosphere during strong catastrophic earthquakes in Turkey on February 6, 2023. It is shown that the ionospheric responses to these earthquakes recorded at distances of 1200–1600 km from the epicentre in the lower ionosphere and at distances of up to 500 km from the epicentre in the upper ionosphere can be interpreted in terms of the propagation of the Rayleigh seismic wave and atmospheric waves – shock, acoustic and internal, that is, those waves that are generated by the earthquake itself. The energy of seismic events was estimated from the ionospheric response.
On Constructing Analytical Models of the Magnetic Field of Mercury from Satellite Data
Authors: Stepanova I. E. , Yagola A. G. , Luk’yanenko D. V. , Kolotov I. I.
Published: April 2024

Abstract—A new method is proposed for analytical description of the magnetic field of the Mercury from the data of satellite missions based on the local and regional versions of the linear integral representation method. The inverse problem on finding the sources of the field is reduced to solving ill-conditioned systems of linear algebraic equations with an approximately set right-hand part. The charts of the isolines of the z-component of the magnetic inductance vector in the Cartesian coordinate system rigidly connected with the planet, as well as the regional S-approximation of the field radial component are plotted. The results of the mathematical experiment on analytic continuation of the magnetic field towards the sources are presented.
Effect of Presowing Gamma Irradiation on the Germination of Tubers and the Growth of Potato Plants of the Meteor Variety
Authors: Allayarova A. S. , Shitikova A. V. , Allayarov S. R. , Demidov S. V. , Allayarova U. Yu.
Published: April 2024

Formation of the potato crop in soddy podzolic soils of the Field Experimental Station of the Russian State Agrarian University—Timiryazev Moscow Agricultural Academy has shown that doses of 200–300 Gy used for the irradiation of seed tubers are most favorable for stimulating the growth and development of potato plants of the Meteor variety. After this radiation treatment of the seed material, the greatest increase was observed in the length of eyes, in the number of eyes and stems, in the amount of photosynthetic active biomass, in the solids content of leaves and stems, and in the amount of starch in the tubers of grown potatoes. All this can be used to increase the yield of potatoes and their consumer qualities
Preparation and Characterization of Mechanically Strong Nanocomposite Latex Materials
Based on Polyurethane/Graphene Oxide
Authors: Baskakov S. A. , Baskakova Yu. V. , Dvoretskaya E. V. , Krasnikova S. S. , Lesnichaya V. A. , Shulga Yu. M. , Vasilets V. N.
Published: April 2024

Nanocomposites based on aqueous polyurethane latex and graphene oxide have been synthesized and characterized. The structure and composition of the nanocomposites were studied using elemental analysis, optical microscopy, IR spectroscopy, DSC, and thermogravimetry. The nanocomposites showed higher thermal stability and increased mechanical strength compared to those of the original polymer. It has been established that the Young’s modulus of latex films after the introduction of 2 wt % graphene oxide increased by a factor of almost 6. In this case, the fracture stress decreased only slightly by 10–15%. The influence of the particle size of graphene oxide on the mechanical properties of the composites was found, namely: composites with larger particles of graphene oxide had a higher Young’s modulus, and their relative elongation at break decreased
Study of the Decay Kinetics of Photogenerated Current Carriers in Ag1 − xCuxGaSe2
Solid Solutions
Authors: Rabenok E. V. , Gapanovich M. V.
Published: April 2024

Краткое сообщение без аннотации и ключевых
Modeling of Kinetic Processes in an Analytical Gas Detector Based on Plasma Electron Spectroscopy
Authors: Saifutdinov A. I. , Sysoev S. S. , Nuriddinov Kh. , Valeeva D. R. , Saiko A. M.
Published: April 2024

Numerical calculations based on a hybrid model of near-cathode plasma (negative glow) of a short glow discharge have been performed to describe processes occurring in a newly developed PLES (plasma electron spectroscopy) detector for gas chromatography. The formation of narrow peaks is demonstrated, which are the spectra of fast electrons generated by Penning ionization from atoms and molecules of helium impurities, such as Ar, N2, O2, and CO2.
Strength Kinetics of Oriented Polypropylene during Radiation-Oxidative Aging
Authors: Dalinkevich A. A. , Piskarev I. M. , Fomin L. V. , Nenasheva T. A.
Published: April 2024

The kinetic features of change in the strength of oriented polypropylene (PP) as a result of radiation oxidation have been established. The relationship between the change in the strength of oriented PP (slit-film yarns) after irradiation in air and the structural characteristics of the polymer is shown. A kinetic model is presented that takes into account the supramolecular (fibrillar) structure of the oriented polymer and the kineticfeatures of radiation-induced oxidation.
Luminescence and Light-Resistance Features of Mixed Europium–Gadolinium Complexes
in Polymer Films
Authors: Mardaleishvili I. R. , Zaichenko N. L. , Koltsova L. S. , Shienok A. I. , Levin P. P. , Ivanov V. B.
Published: April 2024

The effect of gadolinium on the luminescence of europium in mixed complexes with thenoyltrifluoroacetylacetone and 1,10-phenanthroline in poly(methyl methacrylate) and polyethylene films has been studied. The scale of change in light resistance with varying the proportion of gadolinium and the concentration of the complex in the polymer has been estimated. An increase in the relative intensity of luminescence in polyethylene with an increase in the proportion of gadolinium in the complexes has been revealed, themagnitude of which corresponds to a similar effect for complexes in the crystalline state. This effect is absent in poly(methyl methacrylate) films; however, the presence of gadolinium lowers the rate of decrease in luminescence intensity during photolysis.
Radiation-Initiated Dehalogenation of Organofluorine Compounds in Aqueous Solutions
Authors: Tugai O. V. , Kosobutskii V. S. , Sverdlov R. L. , Brinkevich S. D, , Lastovskii S. B.
Published: April 2024

The γ-radiolysis of 2-fluoroethanol-1, 2,2,2-trifluoroethanol-1, 3-fluoropropanol-1, and 4,4,4- trif luorobutanol-1 in aqueous solutions in an inert atmosphere or in the presence of oxygen has been studied. It has been found that the dehalogenation of hydroxyl-containing organic compounds is induced by •ОН and Н• radicals rather than hydrated electrons. The carbon-centered α-hydroxy-β-fluoroethyl radicals FCH2–•CHOH are def luorinated much more efficiently than α-fluoroalkyl radicals, both vicinal (F–•CHCH2OH) and nonvicinal (F–•CHCH2CH2OH). In the absence of oxygen, α-fluoroalkyl radicalseliminate fluoride ions by the mechanism of nucleophilic substitution, and this process is enhanced in the presence of alkali. In an oxygenated medium, the dehalogenation of α-fluoroalkyl radicals occurs via the addition of oxygen molecules to them and the subsequent disproportionation of resulting peroxyl radicals. The dehalogenation of the α-hydroxy-β-fluoroethyl radicals FCH2–•CHOH is inhibited by oxygen through their oxidation.
Peculiarities in the Radiolysis of β-Diketones
Authors: Vlasov S. I. , Smirnova A. A. , Ponomarev A. V. , Uchkina D. A. , Sholokhova A. Yu. , Mitrofanov A. A.
Published: April 2024

Intramolecular hydrogen bonding has a significant effect on the radiolytic transformations of β- diketones. Using the radiolysis of acetylacetone as an example, it has been shown that a hydrogen bond between the hydroxyl and carbonyl in an enol prevents proton transfer from the primary radical cation to the neighboring molecule. As a result, the radiolytic formation of a keto alcohol (4-hydroxy-2-pentanone) was not observed at room temperature, but it was effective under boiling conditions. The intramolecular hydrogenbond contributed to a significant structural stress in the radical cation, which increased the yield of C–OH bond cleavage and the inhomogeneous formation of acetate (4-oxopent-2-en-2-yl acetate) under normal conditions
Effect of Cold Plasma Treatment on Surface Modification of Rice Grains
Authors: Baldanov B. B. , Ranzhurov Ts. V. , Gomboeva S. V. , Badmaeva I. I.
Published: April 2024

The influence of cold plasma of atmospheric-pressure glow discharge on the surface properties of rice grains has been studied. It has been established that as a result of the impact of nonthermal atmosphericpressure glow-discharge plasma on the seed surface, the surface becomes hydrophilic and is characterized by a decrease in the contact angle, an increase in surface energy, and enhancement of surface roughness, indicating the effective formation of polar groups on the surface of rice grains.
High-Spin Photolysis Products of 1,3,5-Triazido-2,4,6-trichlorobenzene in a Frozen 2-Methyltetrahydrofuran Solution
Authors: Chapyshev S. V. , Korchagin D. V.
Published: April 2024

High-spin products of photolysis of 1,3,5-triazido-2,4,6-trichlorobenzene in a 2-methyltetrahydrofuran solution frozen at 6 K has been studied using EPR spectroscopy in combination with quantumchemical calculations. It has been found that the photolysis of this triazide leads to the formation of a mixture of triplet 1,3-diazido-2,4,6-trichlorophenyl-5-nitrene, quintet 1-azido-2,4,6-trichlorophenyl-3,5-dinitrene, and septet 2,4,6-trichlorophenyl-1,3,5-trinitrene. The solvent effect on the EPR spectra and the magneticcharacteristics of nitrenes has been studied.
Photochemical Oxidation of Dimethyl Sulfide with Triplet Nitro Compounds
Authors: Zelentsov S. V. , Ovsyannikov D. V. , Pyslaru A.
Published: April 2024

The mechanism of oxygen atom transfer between triplet molecules of a nitro compound and dimethyl sulfide is considered. This reaction pathway can be one of the possible routes in the reaction of photochemical oxidation of the sulfur compound. Quantum-chemical modeling has shown the feasibility of such a reaction as having a fairly low activation energy. The transition states of the reaction have almost the same structure in various solvents. The calculation of spin densities and charges on atoms in transition states hasshown no significant charge separation. This finding is also confirmed by calculation of the activation parameters of the oxygen transfer reaction involving various solvents. The activation energies remain almost unchanged with an increase in the solvent permittivity. All the data obtained suggest the radical mechanism of oxygen atom transfer with the participation of the triplet nitro compound.
Development of a Kinetic Model for the Direct Oxidation of Benzene to Phenol by Oxygen in Dielectric Barrier Discharge
Authors: Ochered’ko A. N. , Leshchik A. V. , Kudryashov S. V. , Ryabov A. Yu.
Published: April 2024

A simplified model of the process of benzene oxidation by oxygen in a dielectric barrier discharge has been developed. A kinetic scheme of oxidation is proposed that reflects the real chemistry of the process. The simulation results confirm the earlier assumptions about the main stages of the benzene oxidation process with oxygen.
Quantum-Chemical Study of Synthesized Ultrafine Bi2O3–B2O3–BaO Glasses
Authors: Plekhovich S. D. , Plekhovich A. D. , Kut’in A. M. , Budruev A. V.
Published: April 2024

The object of the study is ultrafine bismuth barium borate glasses 20Bi2O3–хBaO–(80−х)B2O3, х = 5, 10, or 20 mol % BaO, synthesized using a unique version of the sol–gel method and holding promise for fabricating functional crystalline glass ceramics, in particular, based on yttrium aluminum garnet. A DSC analysis of the obtained charge material with 0.5 μm spherical particles revealed their glassy state at temperaturesof 450–475°C. The presence of glass in particles of such a small size allows the use of the so-called cluster approximation in a quantum-chemical study of the geometric and electronic structure of glasses by the DFT/UB3LYP/LanL2DZ method. Calculated IR absorption spectra are compared with the experimental spectra of the obtained dispersed samples.
Radiolytic Inactivation of Ponceau 4R Mutagenicity in Aqueous Solution
Authors: Ponomarev A. V. , Kholodkova E. M. , Zotova I. V. , Shumega A. R. , Stepchenkova E. I.
Published: April 2024

The electron-beam treatment of an aqueous solution of the azo dye Ponceau 4R (0.02 g/dm3) at a dose of 1.5 kGy in air led to the complete elimination of color and genotoxicity. The addition of OH radicals to the system of conjugated bonds of the dye (the formation of OH adducts) was a key radiolytic process, which led to the elimination of side groups with lower binding energies
Effect of Ionizing Radiation on Electrical Conductivity of a Tetrafluoroethylene–Ethylene
Copolymer Containing Single-Wall Carbon Nanotubes
Authors: Selkin V. P. , Kopylov S. V.
Published: April 2024

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Kinetics of Ibuprofen Degradation in Aqueous Solution by the Action of Direct-Current Glow Discharge in Air
Authors: Ignatiev A. A. , Ivanova P. A. , Ivanov A. N. , Gushchin A. A. , Shutov D. A. , Rybkin V. V.
Published: April 2024

The kinetics of decomposition of ibuprofen in its aqueous solution by the action of atmosphericpressure direct-current discharge in ambient air has been studied. The treated solution served as both the cathode and the anode of the discharge system. Degradation rates and effective degradation rate constants have been determined. Based on these data, the energy yields and degrees of destruction were calculated for various discharge powers (discharge currents). Discharges in a liquid cathode and anode differ little in the energy yields of degradation. But the rates and rate constants of degradation in the liquid cathode are higher than in the liquid anode. Therefore, the complete destruction of ibuprofen in the liquid cathode is achieved within shorter discharge times. A comparison is made of the destruction efficiencies for the cases of solution treatment using glow, dielectric barrier, and pulsed corona discharges.
Radiation-Induced Alteration of the Reflection Spectra of Diazoquinone–Novolac Photoresist Films by Implantation of Ag+ Ions
Authors: Kharchenko A. A. , Brinkevich D. I. , Brinkevich S. D. , Prosolovich V. S.
Published: April 2024

FP9120 diazoquinone–novolac positive photoresist films 1.5 μm thick implanted with Ag+ ions and supported on the surface of KDB-10 (111) silicon wafers by centrifugation have been studied by measuring reflection spectra. It has been shown that ion implantation leads to a decrease in the refractive index of the photoresist due to radiation crosslinking of novolac resin molecules and a decrease in the density ρ and the molecular refraction RM of the photoresist. It has been established that the reflection coefficient in the opaque region of the photoresistive film increases with the Ag+ implantation dose. The changes observed in the optical properties of the films under ion implantation conditions are explained taking into account radiation-chemical processes in the phenol–formaldehyde photoresist.
Plasma-Enhanced Chemical Vapor Deposition of Thin GaS Films on Various Types of Substrates
Authors: Kudryashov M. A. , Mochalov L. A. , Prokhorov I. O. , Vshivtsev M. A. , Kudryashova Yu. P. , Malyshev V. M. , Slapovskaya E. A.
Published: April 2024

Gallium monosulfide (GaS), a representative of Group III monochalcogenide layered materials, is a wide-bandgap semiconductor. It is considered an ideal material for light detectors in the blue and near ultraviolet ranges of the spectrum. In this work, for the first time, the method of plasma-enhanced chemical vapor deposition (PECVD) was applied to obtain thin GaS films on various substrates, where high-purity gallium and sulfur served as starting materials. To initiate the interaction between the reactants, a nonequilibrium RF discharge (40.68 MHz) plasma at a pressure of 0.1 torr was used. The influence of the substrate nature on the stoichiometry, structure, and surface morphology of GaS films has been studied. The plasmachemical process was monitored using optical emission spectroscopy.
Charge Characteristics of Titanocene Dicarboranyl by the Mulliken Method
Authors: Lukova G. V. , Milov A. A.
Published: April 2024

For the first time, charge characteristics of an organometallic complex with a radiative LMCT (ligand-to-metal charge transfer) state have been systematically evaluated using 124 methods of different levels of theory (for Ti(η5:η1-CpCMe2CB10H10C)2 taken as an example). It has been concluded that the results of calculation in the Mulliken approximation are reliable.
Investigation of the Plasma-Chemical Synthesis of Thin Ga2O3 Films Doped with Zn in One Step in Plasma
Authors: Mochalov L. A. , Kudryashov M. A. , Prokhorov I. O. , Vshivtsev M. A. , Kudryashova Yu. P. , Slapovskaya E. A. , Knyazev A. V.
Published: April 2024

A process for fabricating Zn-doped (up to 10 at %) β-Ga2O3 thin films by plasma-enhanced chemical vapor deposition has been studied. High-purity gallium, zinc, and oxygen were used as starting materials, and hydrogen was chosen as the carrier and plasma gas. A low-temperature nonequilibrium RF (40.68 MHz) discharge plasma at a reduced pressure (0.01 torr) was used to initiate chemical reactions of precursors. Theplasma-chemical process was monitored using optical emission spectroscopy. Structural properties and morphology of the deposited β-Ga2O3 films were studied by various methods.
Chain Oxidation of Hydroquinone by Water Activated by Pulsed Hot-Plasma Radiation
Authors: Piskarev I. M.
Published: April 2024

The interaction of hydroquinone with water activated by hot-plasma pulsed radiation has been studied. In the reactions of hydroquinone with products accumulated in water during irradiation (nitrous and peroxynitrous acids), hydroquinone undergoes chain oxidation to benzoquinone. The mechanism of chain oxidation is analyzed. The decomposition of hydroquinone by corona discharge cold plasma (OH• radicals) was studied. Benzoquinone is not produced by the action of corona discharge; hydroquinone immediately decomposes into smaller molecules. The hydroquinone oxidation process considered can be used to create hydrogen elements based on the hydroquinone ↔ benzoquinone couple.
Mechanism of Interaction of Nitro Compounds with Olefins in Acetonitrile
Authors: Plekhovich S. D. , Zelentsov S. V. , Grimova I. T.
Published: April 2024

The interaction of 4-fluorostyrene with 4-CN-PhNO2 in the presence of various solvents has been simulated by quantum chemistry methods. The reaction mechanism and activation barriers of its stages are proposed. The software package Gaussian03 was used for calculations. The optimal geometric parameters of the structures under study were obtained by means of the DFT/WB97XD/DGDZVP2 methods, the TDSCF/DFT/WB97XD/DGDZVP2 and TD-SCF/DFT/PBEPBE/6-311g++(3d2f,3p2d) methods were used to calculate excited singlet and triplet states, and the IEFPCM model was employed to account for the solvent effects. The transition states were calculated by the TS method using the DFT/PBEPBE/6-311g++(3d2f,3p2d) method.
Heat and Mass Transfer in Spray Drying Processes with Convective-Radiant Energy Supply
Authors: Akulich P. V. , Slizhuk D. S.
Published: April 2024

The article presents a mathematical model, numerical simulation results, and experimental investigations of heat- and mass-transfer processes, and the operating parameters of an experimental spraying plant for dehydration of concentrated solutions with convective–radiant energy supply. The article shows that the heat- and mass-transfer processes, dryer capacity, and evaporated moisture performance can be enhanced by reducing the specific heat consumption due to the impact of infrared radiation on the liquid spray plume area and the creation of a countercurrent vertical flow mode of the coolant.
Distillation Separation of the Isobutyl Acetate–Acetic Acid–Isoamyl Acetate Industrial Mixture
Authors: Polkovnichenko A. V. , Chelyuskina T. V.
Published: April 2024

The process of distillation separation of the isobutyl acetate (IBA)–acetic acid (AA)–isoamyl acetate (IAA) industrial mixture, which is a product of the large-capacity waste processing of the alcohol industry, is considered. Various versions of the process flow diagramm (PFD) are proposed and the operating parameters of the distillation columns for providing isolation of IAA and IBA with purity higher than 99.5 mol % from the IBA–AA–IAA industrial mixture are determined. For the IBA–AA, IBA–IAA, IBA–SF, and AA–SF systems the binary interaction parameters of the NRTL-HOC model were estimated. New experimental data on the liquid–vapor phase equilibrium in the IBA–SF and AA–SF systems at 200 mm Hg are obtained for the estimation of the parameters.
Generalized Dependence of the Viscosity of Particulate-Filled Polymer Composite Materials with Different Types of Structures
Authors: Simonov-Emel’yanov I. D. , Surikov P. V.
Published: April 2024

Models describing the rheological properties of particulate-filled polymer composite materials are analyzed from the point of view of their structure. A mathematical model relating the relative viscosity to the parameters of the disperse structure is proposed on the example of a model system based on low-density polyethylene containing glass microspheres. The rheological properties of particulate-filled composite materials are considered for the first time from the standpoint of the formation of a heterogeneity by particles of a dispersed filler in space and the construction of a polymer matrix in the free space in the form of three functional components (Θ, B, and M). The use of this approach in technological practice makes it possible to estimate the melt viscosity from the parameters of a given type of structure (dependent on the content of dispersed filler) of a particulate-filled polymer composite material.
Semiempirical Method for Determining the Velocities of Phases During Fluidization and Settling in a Self-Similar Region
Authors: Trushin A. M. , Nosyrev M. A. , Ravichev L. V. , Frolova S. I. , Sal’nikova L. S. , Yashin V. E.
Published: April 2024

An expression is obtained for determining the dimensionless velocity in the processes of settling and fluidization for spherical, cylindrical, and cubic particles in a self-similar region.
Comparative Calculation of the Interphases Heat and Mass Transfer in Spray Apparatus for the Regimes of Cocurrent and Countercurrent of Phases with Consideration of the Drag Crisis and Heat and Mass Transfer Crisis
Authors: Simakov N. N.
Published: April 2024

The article presents new details of an algorithm and compares the results of calculating the heat and mass transfer of water and air in spray apparatus for the regimes of cocurrent and countercurrent of phases, taking into account the early crisis of drops drag and the accompanying crisis of heat and mass transfer. The mathematical model used is based on nonstationary differential equations for the flow of a compressible medium, supplemented with the equations of heat and mass transfer from drops to the gas. The known explicit Lax–Wendroff scheme is used in difference analogs of the equations of continuity and phases flow. The distributions of phases velocities and temperatures, and densities of water vapor in air and saturated vapor near the surface of drops in the two-phase flow are calculated to compare the co- and countercurrent flows of phases through the cylindrical apparatus. In particular, the calculations determined the dependences of the average temperatures of the gas and the liquid over the outlet section of the apparatus for each phase on the gas flow through it
Tryptophan Metabolism: A New Look at the Role of Tryptophan Derivatives in the Human Body
Authors: Shatova O. P. , Shestopalov A. V.
Published: April 2024

In modern scientific literature, close attention is paid to the biological role of tryptophan catabolites both in normal conditions and in various pathologies. There are more and more reports that tryptophan metabolism catabolites play a signaling role in the human body and in the intestinal microbial community. Receptors and signaling pathways in the human body, the so-called tryptophan signaling molecules (TrySM), their cellular targets, physiological and metabolic effects are being actively studied. It has now been established that almost all catabolites of tryptophan metabolism are signaling molecules. Many of them realize their signaling role through aryl hydrocarbon receptors (АhR). The dominant pathway of tryptophan metabolism for the human body is the kynurenine pathway, which is the source of universal signaling molecules – kynurenine, quinolinic and kynurenic acids. The indole pathway of tryptophan catabolism, the main one for the microbiota, with the exception of indole formation reactions in immunocompetent cells, is a source of interregional and interspecies signaling molecules – indole and its derivatives: indole-3-pyruvate, indole-3-lactate, indole-3-acetate, indole-3-propionate, indole-3-acrylate, indole-3-butyrate and indole-3-acetaldehyde. Serotonin and melatonin are also universal signaling molecules and have been widely studied in various diseases of the nervous system.