Home – Home – Jornals – Chemistry for Sustainable Development 2024 number 5

We carried out a detailed geological, geochronological, geochemical, and isotope study of diorites from a dike located in the central part of the Baikal uplift of the Siberian craton. The geochemical and isotope data obtained for diorites of the studied intrusion were compared with coeval mafic and intermediate igneous rocks of the southern part of the Siberian craton. The U-Pb (ID-TIMS) baddeleyite age of 1862 ± 7 Ma has been estimated for diorite from a dike located in the area of the Onguren Village. The obtained data are the first reliable age determination for the Paleoproterozoic mafic and intermediate igneous rocks of the Baikal uplift, which are part of the South Siberian postcollisional magmatic belt. The dike is of NE strike. The dike rocks correspond in chemical composition to diorites and are highly differentiated varieties (mg# = 36.5-37.4). There are no significant variations in the composition of diorites in the marginal and central parts of the dike. The rocks are characterized by low contents of TiO₂, P₂O₅, and Nb, high contents of Th, Zr, Ba, and LREE, and low negative values of ε_Nd( T ) (-5.9 to -6.2). We assume that the diorites formed from the enriched subcontinental lithospheric mantle. The obtained geochemical and isotope data show similar negative values of ε_Nd( T ) from -4.3 to -11.6 for most of Paleoproterozoic mafic and intermediate igneous rocks of the South Siberian postcollisional magmatic belt within the Aldan Shield, the Baikal uplift, and the Irkut block of the Sharyzhalgai uplift. These rocks correspond in geochemical features to rocks resulted from the melting of subduction-modified lithospheric mantle sources in the postcollisional extension setting at the final Paleoproterozoic stage of formation of the Siberian craton.

The paper presents data on the age and composition of phlogopite from dikes of ultramafic lamprophyres (aillikites) of the Zima Complex located within the Urik-Iya graben in the East Sayan region (southern margin of the Siberian craton). Samples for study were taken from postcarbonatite dikes of the Bol’shaya Tagna intrusion, Bushkanai dike, and Yuzhnaya volcanic pipe. The studied samples consist of olivine macrocrysts and fully crystallized groundmass composed mainly of phlogopite, perovskite, minerals of spinel and apatite groups, carbonates, and other minerals. Phlogopite is a typical groundmass mineral in the ultramafic lamprophyres of the Zima alkaline ultramafic carbonatite complex. It was also found in polycrystalline inclusions in olivines and in polyphase inclusions in chromites. In the studied samples, the groundmass phlogopite has tabular zoned crystals of greatly varying size and composition. The phlogopite grains show mainly a reverse zoning, with the cores composed of ferruginous high-alumina phlogopite. The intricate zoning probably resulted from the mixing of two magmas. The cores of phlogopites of the Zima Complex aillikites (with Al₂O₃ = 14-18 wt.%, FeO = 7-18 wt.%, and TiO₂ = 3-6 wt.%) formed from early portions of a more evolved aillikite melt. Phlogopite with Al₂O₃ = 10-14 wt.%, FeO = 4-10 wt.%, and TiO₂ = 1-2 wt.% crystallized from the parental aillikite magma. The phlogopite age of the Bol’shaya Tagna aillikites is 635 ± 7 Ma (TGK 3). The age of phlogopite from the Yuzhnaya pipe aillikites is 647 ± 7 Ma (BZT 4/21). The two ages are consistent with the time of formation of Neoproterozoic alkaline ultramafic carbonatite complexes of the Siberian craton and of other occurrences of aillikites resulted from the extension of the Rodinia lithosphere.

Au-Ag mineralization occurrences in sphalerite ores of hydrothermal genesis are paradoxical in view of the incompatibility of these elements in sphalerite. The formation of sphalerite with Au and Ag impurities under hydrothermal crystallization of ZnS at 450 ^oC and 1kbar pressure was studied experimentally. Sn impurity was taken as a source of point defects in crystals modelling the interaction of Au and Ag with vacancies. The Ag solubility in low-Fe sphalerite is estimated as 3.8 ± 0.7 µg/g, Au ̶ ≤ 0.6 µg/g. The main forms of Ag and Au occurrence in sphalerite are the inclusions of (Ag, Au) _x S phases with x varies mainly from 1.8 to 2.0, and Au varies from 0.01 to 0.75 a.p.f.u. The primary forms of the elements in ores might be microinclusions (Ag, Au) _1.8-2.1S or close to (Ag, Au)S at higher f _S2. In presence of Sn, solubilities of Au and Ag become higher. The behavior of Au corresponds to the substitution reaction Sn⁴⁺ + Au⁺ + v^- ↔ 2Zn²⁺ in the presence of two types of vacancy defects (v^-) - the “inherent” vacancies dependent on the crystallization conditions and the vacancies accompanying Sn⁴⁺ incorporation. Ag entrance is seemingly more dependent on f _S2 conditions and does not correlate with Sn. The extra vacancies arise because of metastable crystallization under the conditions of oversaturation of growth medium. This is supported by the spherulite morphology of growth products and the admixture of wurtzite ZnS form. The distribution and cocrystallization coefficients show an increasing trend for both precious metals (PM), due to which Au changes from incompatible to the category of highly compatible elements in sphalerite. The geochemical environments favorable for the formation of imperfect mineral crystals are considered. Such crystals are capable to uptake PMs and other incompatible in “ideal” crystal elements because of their interaction with vacancies, both constitutional (inherent to the substance) and non-equilibrium defects, and surficial nano-sized formations (nonautonomous phases). The evolution of these initially “invisible” forms of PM under metamorphic processes and remobilization of ore substance may result in Au and Ag escape and aggregation into microparticles.

This paper describes a detailed mineralogical and geochemical study (using electron probe microanalysis and secondary ion mass spectrometry) of zircon from rare metal pegmatites of the Polmostundra and Kolmozero lithium deposits (Kola Peninsula, Arctic zone, Russia). The zircons studied here have several distinguishing features. Firstly, anomalously high lithium content (up to 327 ppm Li according to secondary ion mass spectrometry data). Secondly, high hafnium content (up to 39.21 wt.% of HfO₂ according to electron probe microanalysis data). Thirdly, low Zr/Hf ratios (from 0.74 to 4.70). Fourthly, high content of volatile components (up to 5.98 wt.% of H₂O, up to 0.65 wt.% of F, and up to 0.12 wt.% of Cl according to secondary ion mass spectrometry data). Finally, higher content of impurity elements, the main of which are Th, Ta, U, Nb, Ca, and P. It is revealed by the results obtained that the rare metal specificity of the composition of highly fractionated pegmatite melts of the Polmostundra and Kolmozero deposits, from which zircons crystallized, are the key indicator of the high degree of its fluid saturation. The extremely low values of the Zr/Hf ratio for zircons can be explained by the combined influence of fractionation of the initial granitic melt with the accumulation of Li in the residual melt at the final stage of the evolution of pegmatites and the role of fluids saturated with volatile elements. Zircon crystallization occurred at the magmatic stage of pegmatite formation, and zircon alterations occurred at the hydrothermal stage. The nature of the rare earth element distribution in zircons from the Polmostundra and Kolmozero deposits indicates that the formation of the central zones and margins of grains took place during the magmatic and the hydrothermal stage, respectively.

Identifying patterns of geographic differentiation of individual groups of marine invertebrate fauna in the geological past is important for understanding their evolutionary history, solving issues and problems of biostratigraphic division, and correlation of deposits. Paleobiogeographic data is also necessary to identify the development stages of biota and the geological history of marine paleobasins and verify paleogeodynamic reconstructions. In this work, considering the latest data on paleontology and biostratigraphy of the Boreal Triassic, the taxonomic composition and distribution of Upper Anisian ammonoids in various regions of the Boreal realm are revised. A correlation of Upper Anisian deposits of Northeast Asia, British Columbia, Canadian Arctic Archipelago, Svalbard, Franz Josef Land, and Khabarovsk Krai was carried out at the zonal level and a basis was obtained for a comparative analysis of coeval ammonoid faunas. As a result of a qualitative and quantitative comparative analysis of ammonoid assemblages for various phases of the Late Anisian age, it was established that in the Late Anisian age, British Columbia was constantly part of the Canadian province of the Boreal realm, and Northeast Asia was part of the Siberian province. At the end of the Late Anisian age (most of the late part of the Frechites nevadanus or Frechites chischa phases), provincial differences were smoothed out and for the first time, all Boreal regions were included in the Siberian province, except the territory of British Columbia. Analysis of the geographical distribution of some groups of ammonoids in the Late Anisian age and changes in the areas of taxa over time made it possible to identify probable migration routes of Longobarditidae ( genus Longobardites ) and to introduce significant changes in the ideas about the centers of origin and migration of some Beyrichitidae.

This paper presents a solution to the problem of searching for cavernous fractured zones and the zones that determine reservoir heterogeneity in Famennian deposits of one of the licensed sections of the Republic of Bashkortostan. The use of an integrated approach to the study of azimuthal horizontal-transverse isotropy of rocks using wellbore data and modern methods for processing areal seismic data for carbonate deposits associated with the development of organogenic structures is described. The results of using the full-azimuth angular migration technology are obtained. The introduction of high-tech approaches at the research site using full-azimuth seismic data processing, spectral decomposition, AVA/AVAZ inversion, and complex analysis of dynamic properties of the wave field in conjunction with well logging and core data makes it possible to identify the distorted zones of the carbonate reservoir associated with changes in the characteristics of the rock skeleton, the presence of a porous-cavernous-fracture void space and lithological replacement zones, as well as secondary processes, thereby reducing the risks associated with subsequent production drilling.

The degree of organic-matter (OM) maturation in Proterozoic, Paleozoic, and Mesozoic deposits in the Anabar-Khatanga saddle has been determined from examination of the reflectance of macerals (mainly vitrinite). The Proterozoic deposits contain only graphite inclusions of uncertain origin. In the Cambrian, Devonian, and Carboniferous strata, OM has transformed predominantly to apocatagenesis grades (АC_2-3). Similarly transformed OM (АC_1-3) is found in the lower Permian Tustakh and Lower Kozhevnikova formations. In some wells and areas, the degree of OM catagenesis is not higher than МC₁²-МC₂ grades (classification after A.E. Kontorovich). In the Upper Kozhevnikova Formation, catagenesis grades are within МC₁¹-АC₁ in the upper Permian and within МC₁¹-МC₃² in the Triassic. In the Jurassic deposits, OM has transformed to early mesocatagenesis grades (МC₁¹-МC₁²) and reached МC₂ at the most deeply buried segments. In the Cretaceous strata, OM is less transformed, corresponding to PC₃-МC₁¹ or, seldom, higher grades of catagenesis. Some complexes in the Permian, Triassic, and Jurassic-Cretaceous deposits with OM of moderate maturity might be petroleum-promising.

Smectite illitization geothermometry has been used to assess the thermal maturity and hydrocarbon generation potential of the late Paleocene to early Eocene Patala Formation in the Upper Indus Basin. X-ray diffraction (XRD) detected illite, muscovite, quartz, kaolinite, chlorite, and calcite. Comparison between air-dried (AD) and ethylene glycol (EG)-solvated XRD patterns reveals the absence of discrete smectite and interstratified illite-smectite (I-Sm). Additionally, authigenic illite-2M₁ indicates that the Patala Formation has entered the late-stage diagenetic zone or the low anchizone, which lies in the R3 illitization zone. Abundant SiO₂ and Al₂O₃ in the Patala clay fraction indicate the substitution of tetrahedral Si⁴⁺ by Al³⁺ within the smectite interlayers. Likewise, the relative abundance of K₂O to CaO and MgO indicates the exchange of K⁺ with Ca²⁺ and Mg²⁺ during smectite illitization. Scanning electron microscopy (SEM) reveals in situ growth of platy illite crystals that form within the R3 zone. Furthermore, the total organic carbon (TOC) of the Patala shale exposed in Tirah suggests a poor to good source rock. The absence of discrete smectite and I-Sm, combined with the detection of discrete illite in the Patala shale, suggests that hydrocarbon might have potentially migrated from the source to the reservoir rock during smectite illitization.

This paper presents results of experimental studies of a thermal field in the barrel of a shut-in (no fluid movement in the casing) well in relation to determining a behind-the-casing upward flow using the method of active thermometry. The studies are carried out using the physical model of a well that is a vertically located steel pipe with a system of externally attached copper tubes simulating a behind-the-casing flow. The pipe contains a local heating section, above which a temperature probe is located to record thermal disturbance from the heating section. The effect of free convection in a fluid on the temperature field in the pipe during and after heating is described. It is revealed that there are high-frequency temperature oscillations on sensors that record the temperature of the inner surface (wall) of the pipe and fluid above the heating area, whose value reaches higher than 2 °C and decreases when the distance to the heating region becomes longer. There is an empirical relationship that relates the time of arrival of the temperature disturbance front associated with free convection and the distance to the pipe heating region. Azimuthal temperature distribution curves on the inner wall of the pipe above the heating section are constructed in the absence and presence of a behind-the-casing flow. Qualitative criteria have been obtained indicating the presence of an azimuthally localized behind-the-casing flow (sector flow) of fluid based on the azimuthal temperature distribution analysis.

Years after the Chuya earthquake of 2003, geological structures adjacent to the focal area of the Chuya earthquake are still seismically active. The Aigulak focal area is one of them, but energetically the most pronounced. Detailed studies have been carried out with the network of stations of the Altai seismological testing site, supple-mented by temporary stations. The region activated in the form of a local and compact structure measuring 10 × 10 km with focal depths from the first 100 m to 20 km. The focal area is not a subsequent activation along the same fault with the Chuya earth-quake, but is located on a subparallel fault in the nodal region with its branching into three faults. The seismic activation of the Aigulak focal area is not an aftershock pro-cess after a major earthquake, but is an activated structure with a dynamically changing seismic process. An intensive process has formed since the earthquake in 2012 with M_L = 6.1 with a gradual decrease in the number of earthquakes, and in 2019 the Aigulak earthquake with M_L = 5.5 occurred with a very strong aftershock process after it. Our results of an area study of earthquake density in the focal zone indicate a change in the regime over time: from chaotic to self-organizing along short faults. We conclude that the focal area has not reached the maximum level of seismic energy release.

Three-dimensional transport and transformation models make it possible to take into account the vertical heterogeneity of atmospheric processes. However their use requires setting a large number of parameters and significant computing resources, especially when solving inverse and data assimilation problems. A new data assimilation algorithm for a three-dimensional transport and transformation model with unknown emission sources is presented, which uses an approach based on sensitivity operators and ensembles of solutions of adjoint equations implemented in the IMDAF inverse modeling system for distributed memory computers. When tested in a realistic Baikal region scenario, the algorithm enabled, based on the data of integrated vertical measurements simulating remote sensing data, reducing the error in the concentration field by 15%. With the given vertical level of the source location, the errors in the concentration field and in the source were reduced by 93% and 85%, respectively.

The isotopic composition of precipitation is a hydrological tracer of convective processes and is often used to reconstruct paleoclimate. Therefore, it is interesting to consider how the isotopic composition of precipitation changes during the passage of mesoscale convective systems (MCS). Variations in the isotopic composition of oxygen (δ¹⁸О) and hydrogen (δD) in precipitation during the passage of MCS over Tomsk in 2016-2021 were studied. It was found that δ¹⁸О values varied from -14.98 to +0.03‰ with an average of -9.9 ± 3.2‰ and δD values varied from -99.2 to -16.71‰ with an average of -65.1 ± 22.3‰ in MCS precipitation. The relationship between δ¹⁸О and δD is described by the equation δD = 5.45d¹⁸O - 11 ( R ² = 0.62). The values of the regression coefficients show the predominant effect of evaporative fractionation on the formation of the isotopic composition of precipitation. Relatively high isotope ratios corresponded to disorganized convection, and lower isotope ratios characterized the isotopic composition as the MCS area increased. Based on the analysis of back air mass trajectories with the use of the indices of convective instability and satellite sounding and WWLLN network data, regions-sources of moisture for MCS precipitation were detected: the underlying surface and shallow water bodies of the steppe zone in the south of Western Siberia and Northern Kazakhstan. The results of the study can be useful for simulating convection in climate models, as well as for better understanding isotope variations in different paleoarchives for regions with convective activity.

The information on the cloud liquid water path (LWP) is necessary for many applications including global and regional climate modelling, weather forecasting, and modelling of the hydrological cycle. The results of derivation of the land-sea LWP contrast from satellite measurements of LWP by the SEVIRI (Spinning Enhanced Visible Infra-Red Imager) instrument over land and water bodies in Northern Europe are presented. When studying the diurnal cycle of the LWP contrast for some water bodies, two separate maxima were discovered, which were observed nearly symmetrically relative to noon on the UTC time scale. In most cases, these maxima were present at measurement locations in the Gulf of Riga and in the Gulf of Finland in the Baltic Sea. Presumably, these maxima are an artefact of observations caused by the so-called “cloud bow effect”. Calculations of a scattering angle for the satellite measurements at these locations confirmed this conclusion. The problem of filtering out the data and the problem of analysing the data in case of possible manifestation of this confounding effect are discussed. The proposed approach to data analysis and the results can be used to assess the quality of LWP measurements by SEVIRI in various regions of the globe.

The climate of mountain regions is studied much worse than of plain territories. We suggest a model of the distribution of temperature field parameters in the lower troposphere over the Caucasus, which is to enable estimating the thermal resources of mountainous regions. Based on temperature sounding data at altitudes of 1500, 3000, and 5000 m from six aerological stations located on different sides in the mountainous country and regression and statistical analysis, we retrieve the temperature fields and distribution in the lower troposphere. The monthly average characteristics of the temperatures are presented; the effect of orography on the temperature regime is studied. The use of aeroclimatic temperature indicators makes it possible to indirectly estimate the thermal resources of mountain regions from analog station data for their effective use in economic activity.

The relationships between variations in the residual gas content in discs of coniferous and deciduous trees growing in and around Tomsk (southeastern Western Siberia) and the North Atlantic Oscillation (NAO) were analyzed. The results of the work showed that (1) air temperature in Tomsk region significantly correlated with the NAO index; (2) the cross-spectral analysis of the chronologies of gas components of the deciduous tree discs with the air temperature during the growing season indicated the coherent fluctuations around a 4-year cycle; (3) the correlation coefficients of the NAO index with the chronologies of CO₂ (CO₂ + H₂O), and the ring width of the six (of eight) tree discs were found. Based on the results, it is concluded that the North Atlantic Oscillation can affect the life activity of some Siberian tree species (on a 4-year time scale).

Modern changes in the global climate are accompanied by rising air and soil temperatures. How do they affect soil respiration and should we expect a change in greenhouse gas emissions? These questions cannot be answered without studying gas exchange between the soil and the atmosphere. In this paper, the analysis of the greenhouse gas fluxes at the soil-atmosphere interface observed at the Fonovaya Observatory in 2023 is presented. A stable CO₂ and CH₄ uptake throughout the growing season is shown. As for N₂O, on the contrary, a weak positive flux was observed. A steady uptake of carbon dioxide from the atmosphere occurred from May to mid-August; its value attained -600 mg × m^-2 × h^-1 in June and July. The methane flux (sink) attained -0.08 mg × m^-2 × h^-1. The nitrous oxide flux fluctuated near zero with the daily average being within ± 0.02 mg × m^-2 × h^-1. For CO₂, a nonlinear positive relationship between the increase in respiration of vegetation and soil temperature is revealed. Linear temperature dependences are found for methane fluxes in all three chambers, that is, an increase in soil temperature enhances CH₄ uptake. N₂O fluxes show very weak positive dependence on the soil temperature in both transparent chambers (with vegetation and without it). The estimates of the contribution of CO₂ fluxes from the soil showed that during nighttime, microbial respiration can contribute from 46.7 to 77.9% to the total respiration of the grassland ecosystem. On average, the share of soil methane uptake per day due to diffusion and oxidation by methanotrophs not associated with plants varies from 5.3 to 48.3%. The contribution becomes smaller during the daytime and increases at night. The contribution of soil with removed vegetation to the total N₂O emission can attain 92.3%. The results expand knowledge about soil-atmosphere gas exchange under changing climate conditions.

The volume concentration of fine and coarse aerosol ( V_f and V_с ) in the near-water layer and the aerosol optical depth (AOD) of the atmosphere are generalized on the basis of long-term studies in Eurasian sector of the Arctic ocean. The mean AOD value at 0.5 mm is 0.061, the Angstrom exponent is 0.9, the concentrations of fine and coarse aerosol are 0.35 and 2.5 μm³/cm³, respectively. The greatest content of fine aerosol is observed in the atmosphere over Norwegian and Barents Seas. The spatial distribution is characterized by the decrease in the concentrations in northern and eastern directions: the mean value V_f becomes 1.7 times less from Barents Sea to Chukchi Sea (from 0,43 to 0.26 μm³/cm³). The very high concentration of coarse aerosol are observed in south-east part of Kara Sea: the mean V_с is 4.18 μm³/cm³. Then the coarse aerosol concentration decreases relatively to Kara Sea in eastern and western directions by several times.

The influence of synoptic conditions at the 700 hPa isobaric surface on meteorological regime and melt of the Sygyktinsky glacier (Kodar Range) in the 2021 ablation season was studied. Totally 15 weather types were classified using the Jenkinson and Collison method. It was found that the most frequent types are cyclones (24%) and anticyclones (20%). A significant dependence of the meteorological regime of the glacier on synoptic conditions was revealed. Anticyclonic types are characterized by high temperatures and low relative humidity and cloudiness. For cyclonic types, the opposite relations are observed. It was found that the radiation regime on the glacier and its melting rate depend on synoptic conditions. The greatest contribution to melting was made by anticyclonic weather types (44%), and the least by cyclonic types (26%). The net radiation of the glacier in anticyclones was 2-2.5 times greater than in cyclones, and the ablation rate was 1.6-1.8 times greater. The differences between the energy fluxes used for glacier melting under different synoptic patterns are explained by the cloudiness. The different atmospheric circulation regimes over the Kodar significantly affected the deglaciation of the Kodar glaciers in recent decades.

The absence of an adequate optical model for cirrus clouds currently poses a significant challenge in interpreting ground-based and space-borne lidar data. This, in turn, leads to a lack of up-to-date information for climate modeling and daily weather forecasting. Existing optical models typically assume that ice crystals in cirrus clouds have an ideal shape, which is often not the case. This article proposes an optical model for clouds which consists of the most common irregularly shaped particles, specifically hollow hexagonal columns. The model takes into account the actual distributions of particles in the cloud over both depth of the cavity and particle size. Additionally, the model considers the scenario of a cloud containing a mixture of ideal hexagonal columns and hollow hexagonal columns, which significantly enhances the model reliability. The resulting model holds great practical importance for laser sounding of the atmosphere.

The substantiation of the design and technical description of the turbulent lidar BSE-6, intended for installation on board aircraft, is given. In order to reduce the overall dimensions of the system, both sides of the optical bench are used: a transceiver is installed on one side, and a receiving module is mounted on the other. The heat-generating elements are placed in separate insulated ventilated sections. To minimize the deformation of the optical bench, external air is pumped through its middle. The lidar adjustment procedure is described. The quality of the assembly and alignment was tested by comparing the theoretical calculation with real echo signals. The system was also tested for thermomechanical stability.

Ozone is a strong oxidizer, so monitoring the state of the ozonosphere is one of the most important tasks in ensuring the safety of human life and health. There are a number of methods for studying ozone, among which a special place is occupied by the lidar method of remote detection and identification using selective absorption of laser radiation due to its has maximal sensitivity. V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences solved the problem of monitoring the entire ozonosphere over Tomsk by combining existing lidar systems: three measuring systems of the Siberian Lidar Station and a mobile ozone lidar. Lidars are designed to study the ozonosphere using the method of differential absorption and scattering, as well as to study aerosol fields using single elastic scattering. The systems are based on SOLAR and LOTIS TII Nd:YAG lasers, a Lambda Physik laser, and receiving Cassegrain (0,35 m diameter) and Newton (0,5 m diameter) telescopes. Lidars operate in the photon counting mode and record lidar signals with a spatial resolution of 1.5 to 160 m at probing wavelengths of 299/341 nm in the altitude ranges ~ 0.1-12 km and ~ 5-20 km, and 308/353 nm in the altitude range ~ 15-45 km. By combining three measuring systems, a full-scale experiment of lidar sensing of the atmosphere in Tomsk was carried out. The result of retrieval of the vertical profile of ozone concentration is presented. For the first time in Russia, lidars have covered the entire ozonosphere. The lidar complex sounding results will be used in the network of Roshydromet stations, in adjusting the quasi-three-year model of the vertical distribution of ozone concentration and aerosol, in comparison of lidar and satellite data, and in assessing the influence of climate-forming factors in Western Siberia.

The study of the spatiotemporal structure of optical turbulence and the development of methods for determining its characteristics at different altitudes in the atmosphere are of great importance for astronomical adaptive optics. Design of an adaptive optics system and technical characteristics of its components largely depend on optical turbulence along the line of sight a telescope. In this paper, the method for estimation of vertical profiles of the air refractive index structure characteristic is modified. Based on the ERA5 reanalysis data, this method was used to derive statistically representative vertical profiles of the air refractive index structure characteristic and the outer scale of turbulence at the Large Solar Vacuum Telescope (LSVT) site. The problem of estimating the turbulence outer scale is discussed taking into account surface mast micrometeorological measurements and optical measurements at the LSVT. The results are the basis for constructing a multi-mirror adaptive optics system for the LSVT. In particular, these profiles are important for further refinement of the optical conjugation heights. The suggested method can also be used to describe optical turbulence over other ground-based solar telescopes.

This paper considers approaches to accounting for tax losses. It is determined that the accounting methodology depends on the way they are utilised. Tax losses claimed as a refund (Loss Carry-Back) represent a financial claim to the state, therefore they are qualified as an asset (receivable) within the current tax component. Losses claimed as a deduction (Loss Carry-Forward) qualify as a deferred tax asset in the deferred component. Three approaches to accounting for tax losses attributable to deferred taxes are characterised: conservative, mixed and positive. It is established that in the concept of temporary differences the economic benefit from the resulting tax loss is identified in relation to its tax base; in turn, in the concept of temporary (term) differences the tax effect is part of the «difference» between the accounting and tax result. It is concluded that the Russian Accounting Standard (PBU) 18/02 «Accounting for corporate income tax calculations» has the following shortcomings: tax losses are incorrectly classified, and the methodology of their accounting is not defined due to the distorted base of tax effects distribution. The results of this work may serve as a basis for improving national accounting standards.

The article examines the volatility of one of the key indices on the Russian stock market. Through the prism of statistical data analysis have been identified four key risk groups. The use of this method is justified by the obtained results. The proposed methodology can be used as a basis for forming an investment portfolio of shares with better diversification characteristics.

In the article author presents two approaches to libraries: functional and user defined. From the point of view of functional significance, the library performs the function of personality formation, educational, memorial, and communicative functions. From the point of view of the quality of services received by visitors, the library appears as an architectural, construction and professional library synthesis. The user can evaluate the quality of the services provided in real and virtual space. The library can provide leisure services - clubs, clubs, evenings, lectures, concerts. The functional importance of the library, combined with the high quality of the services provided, should be an attractive place for visitors. To research the real state of affairs, the results of sociological research conducted by All-Russian Center for the Study of Public Opinion in Russia in 2011, 2015, 2022, as well as in libraries in Novosibirsk in 2020 and 2024 are presented. All-Russian Center’s for the Study of Public Opinion results reflect attendance and solutions to the problem of low attendance. The results of the Novosibirsk study reflect an assessment of social attitudes towards libraries. Such an assessment was carried out through a content analysis of the system for collecting customer feedback on products, services, and organizations of Flame. The results of the study of Novosibirsk libraries were compared with some of the results of All-Russian Center for the Study of Public Opinion. The author concluded that the problems of non-attendance are somewhat “far-fetched”, which hide personal lack of activity, low motivation to work with book publications. The results of the research can be used in planning the library’s activities for the development of a user service system.

Parallel algorithm for semi-implicit particle-in-cell method with energy and charge conservation The article is devoted to the construction of a parallel algorithm for calculating plasma dynamics by the particle-in-cell method using a semi-implicit scheme that conserves energy and charge. This scheme is a two-stage predictor-corrector, where at the prediction stage the semi-implicit Lapenta method is used, in which the energy-conserving linear current does not satisfy the local Gaussian law, and at the correction stage the currents, electromagnetic fields and particle velocities are corrected so that the difference laws of conservation of energy and charges were carried out accurately. This approach turns out to be effective for modeling multi-scale phenomena with a sufficiently large time step, however, it is resource-intensive, since it requires not only solving two systems of linear equations per step, but also rebuilding the entire matrix of the system. The authors have developed a matrix-operator algorithm for the software implementation of this scheme, which makes it possible to effectively parallelize calculations, as well as use various libraries for working with matrices and solvers for systems of linear equations. To construct the matrix, a row-by-row storage algorithm is used with searching for elements through a hash table, which reduces the amount of memory used, the number of thread synchronizations and can significantly speed up calculations. The algorithm in question has been successfully applied in the Beren3D code.

In this paper, a linear second-order finite difference scheme is proposed for the Allen-Cahn equation with a general positive mobility. The Crank-Nicolson scheme and Taylor's formula are used for temporal discretization, and the central finite difference method is used for spatial approximation. The discrete maximum bound principle (MBP), the discrete energy stability and L^∞-norm error estimation are discussed, respectively. Finally, some numerical examples are presented to verify our theoretical results.

We present in this work a convergence analysis of a Finite Difference method for solving on quadrilateral meshes 2D-flow problems in homogeneous porous media with a full permeability tensor. We start with the derivation of the discrete problem by using our finite difference formula for a mixed derivative of second order. A result of existence and uniqueness of the solution for that problem is given via the positive definiteness of its associated matrix. Their theoretical properties, namely, stability on the one hand (with the associated discrete energy norm) and error estimates (with L²-norm, relative L²-norm and L^∞-norm ) are investigated. Numerical simulations are shown.

The manuscript presents the results of an application of a numerical method to solve one-dimensional hyperbolic equations. These equations simulate the dynamics of a liquid in a pipe with varying cross-sections. The equations are written in terms of pressure-head and discharge. Radial-basis functions and least-squares optimization are used for the numerical simulation. This numerical method is specialized for working with arbitrary nodal distribution in the problem domain. The basics of the application of the numerical method were introduced in our previous work. In the current work, we updated previously applied methods by means of getting rid of the time-marching approach and applying another adaptive refinement technique. Three cases of the simulations of the reservoir-pipe-valve system are described, indicating that the sharp time-gradient phenomenon is reproduced by the model.

The paper presents a Symmetric Hyperbolic Thermodynamically Compatible model of a saturated porous medium for the case of finite deformations and its linearisation for the description of small amplitude seismic wave fields in porous media saturated with fluid. The model allows us to describe wave processes for different phase states of the saturating fluid during its transition from solid to liquid state, for example during thawing of permafrost and decomposition of gas hydrates under the influence of temperature. To numerically solve the governing equations of the model, a finite difference method on staggered grids has been developed. It was used to perform test calculations for a model of the medium containing a layer of gas hydrate in a homogeneous elastic medium. The study showed that the characteristics of the wave fields in saturated porous media depend significantly on the porosity, which varies with temperature.

This work provides a high accuracy analysis of the reduced Adini Stokes element method developed in [7] for the Brinkman model. We show that this method is uniformly convergent for the velocity with convergence order O(h ²) in a mesh- and parameter-dependent norm over general quasi-uniform rectangular meshes. A proper postprocessing technique is also proposed to improve the precision of the pressure. Numerical examples confirm our theory.

The article investigates the application of hyperbolization for parabolic equations to the material and thermal balances' equations for a mathematical model of oxidative regeneration of a spherical catalyst grain with detailed kinetics. The initial spherical grain model is constructed using a diffusion approach. It is a nonlinear system of differential equations in a spherical coordinate system. The material balance of the gas phase is described by diffusion-convection-reaction equations with source terms compiled for concentrations of substances of the gas phase; the balance of the solid phase is represented by nonlinear ordinary differential equations. The thermal balance equation of the catalyst grain is the thermal conductivity equation with an inhomogeneous term corresponding to the grain heating during a chemical reaction. Slow processes of heat and mass transfer in combination with fast chemical reactions lead to significant difficulties in the development of a computational algorithm. Hyperbolization of the parabolic equations is applied to avoid the computational complication. It consists in the introduction of a second time derivative multiplied by a small parameter, in order to expand the stability area of the computational algorithm. An explicit three-layer difference scheme is constructed for the modified model. It is implemented in the form of a software module. The convergence analysis of the developed algorithm is presented. A comparative analysis of the new computational algorithm with the previously constructed one is carried out. The advantage of the new algorithm while maintaining the order of accuracy is shown. The result of the implemented new algorithm is the profiles of the distribution of temperature and substances along the radius of the catalyst grain.

Many branches of science and technology need new materials. Different methods are used to obtain them. In particular, one of the promising methods used both at the stage of preparation for the thermal synthesis of materials and as an independent method is the mechanical activation of solids. Research carried out by domestic and foreign scientific organisations is devoted to the development of fundamental principles of mechanochemical technologies. This review summarises and formulates some patterns of mechanochemical reactions, such as the reactions of hydrated compounds and mechanically stimulated solid-phase thermal reactions, and indicates the most effective ways of their use. Examples of the synthesis of materials with valuable properties for use in modern technology are presented.

The present review is concerned with advances in the area of hydroxyapatite mechanochemistry. The features of the mechanochemical method for obtaining this mineral, the reactions proceeding in the reaction chamber, the parameters affecting the process efficiency are considered, and the advantages of the method are listed. It has been shown that rapid mechanochemical synthesis of not only stoichiometric hydroxyapatite, but also various options of substitution in its structure within a wide range of concentrations can be carried out in a high-energy planetary mill at a high frequency of vial rotation.

We consider the influence of mechanical activation and radiation-thermal sintering on the synthesis of indium lead tantalate, used in optical electronics and capacitor-based technologies, and the system (1 - х )Pb₂YbNbO₆ + х Pb₂FeNbO₆ ( х = 0.1), the solid solutions of which exhibit high di-, piezo- and magnetoelectric characteristics. The conditions of perovskite and pyrochlore phase formation during both mechanochemical synthesis and subsequent sintering within a wide temperature range with different electron beam exposure times are investigated. To reduce the electrical conductivity of the ceramic, lithium carbonate, which is also a stabiliser of perovskite structure, was introduced into the batch. It has been shown that the characteristics of the final product are determined by the chosen conditions of batch preparation for sintering. The methods of such preparation differing in the order of mechanical activation and the conditions for introducing the components are compared. The optimal conditions have been established that make it possible to obtain piezoceramics with the largest amount of the perovskite phase and maximum density. The prospects of using radiation-thermal sintering on several piezoceramic systems were assessed. It has been established that a number of intermediate phases are formed during radiation-thermal synthesis, though these phases never appeared during conventional sintering. The results obtained in the work suggest that sintering of some lead-containing samples at an accelerator under the action of the electron beam is a promising method to synthesise a monophase complex oxide with perovskite structure. The developed method is of practical interest for obtaining piezoceramics.

The stages of development and application of mechanical activation, mechanochemical and autoclave-based technologies for the purpose of enhancing the efficiency of industrial chemical and technological processes are considered. The development of technologies for processing rare metal raw materials and products containing precious metals is shown, accompanied in parallel by the development of technological equipment based on mechanical activation and autoclave treatment. The developed processes and equipment were assimilated into actual technological charts and transferred for operation at industrial enterprises.

In recent years, new classes of lithium-excess cathode and anode materials with disordered rock-salt structure (DRX), in which any channels for Li⁺ ion diffusion are absent, have attracted increased interest. In DRX cathode materials of Li _y (Me₁Me₂)_{2- y} O₂ composition, Li⁺ and transition metal ions (Me) are equally likely to occupy the same octahedral positions in the lattice, and the diffusion of Li⁺ ions occurs by hopping from one octahedron to another through an intermediate tetrahedron (o-t-o diffusion). The presence of fluorine in oxyfluorides DRX-F (Li_{1+ x} (MeMn³⁺)_{1- x} O_{2- y} F _y , where Me = Ti⁴⁺, Nb⁵⁺) affects the local ordering of Mn³⁺ ions, the stability of the redox couple O^2-/O^- and its contribution into specific capacity. On the other hand, high-entropy oxides (HEO), which are single-phase oxide systems containing five and more cations, were synthesised by mixing five oxides CoO, CuO, MgO, NiO and ZnO in equimolar ratios, followed by thermal treatment at 1000 °C. Stabilisation of single-phase solid solutions Co_0.2Cu_0.2Mg_0.2Ni_0.2Zn_0.2O and Li _x (Co_0.2Cu_0.2Mg_0.2Ni_0.2Zn_0.2)_{2- x} O_{2- x} F _x (0 ≤ x ≤ 1) with a rock-salt crystal structure turned out to be possible due to the large contribution of the entropy of mixing to the Gibbs free energy. Another group of anode materials are high-entropy oxides with a spinel structure (HES), for example (Cr_0.2Fe_0.2Mn_0.2Co_0.2Ni_0.2)₃O₄ obtained by solid-state synthesis at T = 500-1000 °C in air. After ball grinding, the particle size is reduced to 20 nm. The initial specific capacity during cycling in the 0.01-3.0 V range is 1333.6 mA×h/g and decreases to 329.9 mA×h/g after 20 cycles. A comparative investigation of synthesis conditions, crystal structure, morphology and electrochemical characteristics has been carried out for the four classes of high-entropy oxides: 1) Li _y (MeMn³⁺)_{2- y} O₂, где Me = Ti⁴⁺, Nb⁵⁺; 2) Li_{1+ x} (MeMn³⁺)_{1- z} O_{2- y} F _y , где Me = Ti⁴⁺, Nb⁵⁺; 3) Li _x (Co_0.2Cu_0.2Mg_0.2Ni_0.2Zn_0.2)_{2- x} O_{1- x} F _x ; 4) (Cr,Fe,Mn,Co,Ni)₃O₄.

Electrochemical methods in combination with the technique of electrode surface renewal by cutting in dilute aqueous solutions of 0.1 М NaClO₄ with the addition of dodecanethiol (DDT) at controlled potential were used in the work. This made it possible not only to overcome the problem of obtaining an oxide-free metal surface but also to carry out in situ investigation of the formation dynamics and properties of the resulting DDT layers by voltammetry and chronoamperometry, and to determine the conditions for the rapid formation of strong insulating nanofilms on nickel and cobalt. The trends in the influence of various factors (the nature of electrode metal, DDT concentration, the presence of oxygen in solution, the addition of ethanol) on the kinetics of formation and blocking properties of DDT nanofilms are established. The processes of adsorption on Co and Ni were determined to be similar, but adsorption on nickel is slower. For instance, at the dodecanethiol concentration of 10^-3 mol/L, nanofilm formation on Ni lasts for ~30 min, and on Co for ~10 min . It is shown that the adsorption behaviour of DDT on these metals strongly depends on the concentration of DDT and ethanol in solution and less significantly on the presence of oxygen in the solution. The presence of oxygen in the solution slows down this process and slightly reduces the inhibitory properties of nanofilms. The introduction of ethanol into a DDT-containing solution of sodium perchlorate leads to significant acceleration of the process of dodecanethiol self-assembly on nickel and cobalt in a wide ethanol concentration range. The best insulating properties of monolayers are obtained in water-ethanol solutions with ethanol concentration 40-60 % on DDT/Ni electrodes and 20-50 % on DDT/Co electrodes.

The processes of potato starch swelling, dispersion, dissolution and hydrolysis during thermal heating of water - starch suspension in a thermal shaker and during mechanical treatment in a hydro-pulse reactor are considered. The conditions of mechanical treatment and heating were chosen to provide the same heating rates of the suspension in both installations. This allowed us to separate the influence of thermal and mechanical effects on starch grains and to find that during mechanical processing at temperatures below gelatinisation point, dispersion of starch grains occurs, followed by gelatinisation, while when heated, at first gelatinisation of starch grains occurs, and then their destruction is observed. It is shown that under mechanical action about 70 % of amylose from starch granules passes into solution after treatment for 40 min, while no noticeable release of amylose into the solution is observed as a result of thermal treatment for the same time. It is found that during mechanical processing of the water-starch suspension, both amylose and amylopectin are immediately released into the solution, while during heating, amylose is primarily dissolved, and only after heating the suspension for 340 min at 95 °С the dissolution (leaching) of amylopectin begins. The rate of the initial stage of acid hydrolysis of starch at 90 ºC and pH 2.4 under mechanical processing is approximately 3 times higher than in the case of suspension heating in the thermal shaker. With longer treatment, the rate of mechanochemical acid hydrolysis decreases and becomes only 1.3 times higher than the rate of thermal hydrolysis.

Using the mechanochemical method, supramolecular compositions of a potential anthelmintic, artesunate (ARS) with sodium glycyrrhizinate (Na₂GA), were obtained in different mass ratios of the components included in ARS-Na₂GA complex (1 : 5, 1 : 10, and 1 : 20). The formation of an inclusion complex of ARS with Na₂GA micelles was confirmed by NMR relaxation and the nuclear Overhauser effect (NOESY). It has been established that the ARS-Na₂GA complex (1 : 10) has optimal physicochemical properties for further biological studies on the helminths Opisthorchis felineus , which cause opisthorchiasis in humans and animals. Experiments in vitro showed that ARS-Na₂GA complex (1 : 10) had a more pronounced inhibition of motility both in invasive individuals of O. felineus (metacercariae) and in adult trematodes (maritae), compared with pure ARS, and even at low concentrations (0.1-10 µg/mL) for maritae. Despite the fact that the dose of ARS in the composition of ARS-Na₂GA (1:10) was 11 times lower, the efficiency coefficient (IC₅₀) declined 2.4-fold (for metacercariae) and 1.45-fold (for maritae) with respect to pure ARS. The results obtained indicate the availability of using the new complex for further studies on O. felineus -infected animals.