Home – Home – Jornals – Journal of Applied Mechanics and Technical Physics 2026 number 1

The article summarizes published and new geological, geochronological, biogeographical, paleomagnetic, and petrological-geochemical data to support the tectonic zoning of the Central Asian Fold Belt (CAFB) and its Vendian-Paleozoic geodynamic evolution as a complex folded structure consisting of deformed fragments of collisional and accretionary orogens. It has been shown that the Central Asian-Siberian Platform was formed in the zone of junction of the collisional and accretionary margins of the Siberian craton, similar to the modern tectonic interactions between the Indo-Atlantic and Pacific global tectonic segments of the Earth and Eurasia. It has been shown that in the Vendian and Early Ordovician, there were two active margins around the Siberian craton: the collisional Tuvo-Mongolian margin and the accretionary Kuznetsk-Altai margin, which separated the craton from the tectonic plates of the Paleo-Asian Ocean (Indo-Atlantic segment) and the Paleo-Pacific Ocean (Pacific segment), respectively.A distinctive feature of the Paleoasiatic Ocean plate is complex structure, which includes fragments of oceanic crust and Precambrian Gondwana microcontinents with fragments of the Grenville orogeny. Fragmentary Grenville zircons (1.3-0.9 billion years old) are widely found in the Vendian-Paleozoic sedimentary deposits of various geodynamic settings of the collisional orogen. A distinctive feature of the accretion orogen is the widespread presence of oceanic crust fragments and the absence of Precambrian blocks of Gondwana, and as a result, the absence of Granville-age clastic zircons in the Vendian-Paleozoic sedimentary rocks of various geodynamic settings. The Early-to-Middle Paleozoic Charysh-Terekta-Ulagan-Sayan-Olkhon suture-shear zone separates the collisional orogen from the shelf of the back arc basin located in the northern part of the Altai-Sayan folded region framed by the Siberian craton. The suture-shear zone consists of fragments of the Vendian-Early Paleozoic oceanic crust of the Back Arc basin, Ordovician blue shales and Ordovician-Silurian turbidites, Late Silurian-Devonian collisional metamorphic rocks and granites. Based on the structural position of the suture-shear zone and the data of petrological and geochronological studies, it is concluded that it is a subduction-collision complex formed at the site of the back-arc basin of the Vendian-Cambrian Tuva-Mongolian island arc. Late Paleozoic shifts and thrusts manifested themselves in the CAFB in the Late Devonian-Early Carboniferous as a result of the collision of the Kazakhstan-Baikal orogen (composite continent) with the Siberian craton with the formation of the North Asian continent, and in the Late Carboniferous-Triassic as a result of the collision of the East European and North Asian continents. As a result of collisional events, the initially linear structures of the collisional and accretionary orogens were deformed into large oroclinal folds, divided by shifts and thrusts into many fragments, where the Vendian-Paleozoic structures are complicated by thrust-fold deformations.

The results of magnetic survey investigations conducted in the floodplain areas of the Yellow and Black rivers in the Lori Region of Armenia (northern part of the Republic of Armenia) are presented. Based on field observations, digital and graphical maps of the anomalous magnetic field (∆Ta) and its three-dimensional model were constructed. Analysis of the anomalous magnetic field structure made it possible to identify a number of positive and negative anomalous zones associated with geological formations differing in magnetic properties. It has been shown that the positive anomalies are caused by the presence of ultrabasic rocks (peridotites, pyroxenites) exposed along the left bank of the Yellow River and the right bank of the Black River. An extensive negative anomaly zone has been identified and interpreted as a reflection of a tectonic fault zone and the adjacent thick area of hydrothermally altered rocks. Comparison with the data on the physical properties of rocks confirmed the high contrast of magnetic characteristics between the ultrabasic and ore-hosting rocks.

The article presents algorithms for numerical modeling of electrical micrologging signals and calculation results in geoelectric models of impermeable rocks and the borehole environment of a porous, permeable reservoir. This research may be useful for developing an integrated approach to the quantitative interpretation of electrical logging data. A joint numerical analysis of electrical logs measured by conventional probes and microprobes will enable refining the radial electrical resistivity distribution in the borehole environment of oil-gas reservoirs. This, in turn, will provide additional information when jointly solving the problem of drilling mud filtration and numerical inversion of electrical logging data, resulting in a more accurate assessment of reservoir porosity and permeability. We have developed software for numerical simulation of electrical micrologging signals – those from a microgradient, micropotential and microlaterolog probe with focusing. We employ a finite element algorithm with an arbitrary position of the probes in a cylindrically-layered geoelectric model, and a finite difference algorithm for a microgradient and micropotential probe in a horizontally-layered model. Test calculations of the signals in geoelectric models of Western Siberia terrigenous deposits are presented. The models describe impermeable sediments as well as layers with the mud cake and invaded zone at different resistivity ratios. The model parameters correspond to Lower Cretaceous oil-gas reservoirs exposed with polymer-clay drilling muds. The analysis of the calculated micrologging signals reflects a small investigation depth of microgradient and micropotential probes, and a strong dependence of the signals on the drilling mud and mud cake resistivities. Numerical modeling in the class of a cylindrically-layered model has allowed us to obtain the radial resistivity change in the borehole environment of an oil-gas reservoir.

Experimental researches focusing on modeling of interaction between eclogitic and lherzolitic garnets with reduced and oxidized sulfur-rich fluids are conducted using multianvil high-pressure apparatus of “split-sphere” type (BARS). Experiments are carried out in garnet-sulfur-carbon and garnet-anhydrite-carbon systems at the pressure of 6.3 GPa and the temperatures of 1150, 1300, and 1450 °С in graphite ampules, as well as in Pt-ampules with hematite buffering container. It is experimentally demonstrated that interaction of both reduced and oxidized sulfur-rich fluids with mantle garnets leads to their partial dissolution and recrystallization, and to the formation of zoned crystals with decreased iron content in rims. Apart from that, this interaction also results in (1) garnet carbonatisation accompanied by formation of the magnesite±dolomite+kyanite+coesite assemblage, and (2) garnet sulfidation with formation of pyrite (1150-1300 °С) or sulfide melt (1450 °С) as inclusions in garnets and in interstitial space. As a result of conducted experimental researches it is established that indicatory characteristics of mantle garnets that underwent metasomatism by sulfur-rich agents, are decreased FeO content in peripheral crystal zones relatively to their centers, and formation of sulfide inclusion in the zones borders. In this paper we also present the first data on diamond dissolution in the silicate-sulfur-carbon systems under lithospheric mantle P,T-parameters that simulate mantle metasomatism of garnet-bearing lithologies by sulfur-rich fluids. It is found that under such conditions diamond crystals undergo partial dissolution resulting in formation of characteristic etching pits (negative trigons on {111} and rectangles on {100}).

Spectral decomposition is a widely used method of qualitative seismic interpretation, whose key limitation lies in the subjective selection of frequency components for visualization. Existing approaches based on the analysis of the integral Fourier spectrum do not account for the temporal localization of the signal’s spectral content. This study introduces a new method for the automatic selection of frequencies based on approximating local spectra obtained via the Short-Time Fourier Transform (STFT) with a sum of three Morlet wavelet spectra. This approach enables the extraction of time-dependent frequency trajectories that capture the evolution of the signal’s spectral content, rather than relying on a static set of frequencies over the entire interval. The optimization problem is solved using the differential evolution algorithm. The method was tested on data from fields of the West Siberian petroleum province. Quantitative evaluation using Shannon and Rényi entropy metrics, as well as a colorfulness metric, demonstrated increased informativeness of RGB images compared with traditional approaches. The proposed method reduces interpretation subjectivity and ensures reproducibility of results.

Experimental studies aimed at assessing the possibility of diamond crystallization during interactions of alkaline earth and transition metal carbonates with sulfur, as well as at characterizing the obtained diamond crystals and inclusions in them, were carried out on a multi-anvil high-pressure "split sphere" apparatus (BARS). The experiments were performed at constant P,T,t-parameters: 6.3 GPa, 1550 ºС and a duration of 20 hours, in the Mg,Ca-carbonate-sulfur system with different CaO/MgO ratios and Fe,Mg,Ca-carbonate-sulfur system with variable FeO/CaO/MgO proportions. It was experimentally established that in the alkaline earth carbonate-sulfur systems, a Ca,Mg-carbonate melt with dissolved sulfur (1.2-6.0 wt.%) is formed, which is a diamond growth medium. The stable growth form of diamond crystals is the octahedron, and an increase in the Ca# of the system is accompanied by an increase in the growth rate of the {111} faces. It was demonstrated that in the Fe,Mg,Ca-carbonate–sulfur system, the crystallization medium and the source of diamond carbon is the Fe,Mg,Ca-carbonate melt with dissolved sulfur, and diamond growth occurs as a result of the redox interaction of the sulfide and carbonate melts. With an increase in the ferruginousity of the system from 0.41 to 0.78, there occurs (1) an increase in the growth rate of the {100} faces (from 1.0 to 5.4 μm/h); (2) a change in the predominant elements of the octahedron face microrelief from triangular growth layers to hexagonal vicinals; and (3) an increase in the number and size of inclusions, as well as the evolution of their phase composition. Diamond inclusions are formed by melt preservation on the {100} faces during the transformation of a cuboctahedron into an octahedron. The inclusions contain quenched carbonate melt (quenching phases — carbonate, magnetite, and graphite), sulfur melt, and Fe-S-O melt. The discovery of a carbonate+magnetite+graphite association in the inclusions confirms the occurrence of a siderite redox dissociation reaction (3FeCO₃ = Fe₃O₄ + 3C⁰ + 2.5O₂ fluid) at the P,T-parameters of the lithospheric mantle. These results shed light on the possible origin of magnetite inclusions in upper-mantle diamonds and suggest that the presence of magnetite in syngenetic inclusions may be an indicator of the participation of iron-bearing carbonates in natural diamond formation processes. The results of the conducted studies indicate that Mg,Ca- or Fe,Mg,Ca-carbonate melts with dissolved sulfur can be classified as natural diamond-forming environments, and the identified features of the morphology of diamond crystals, the specifics of its growth and the composition of inclusions depending on the cationic composition of the carbonate melt with dissolved sulfur can be used as indicators of diamond crystallization in similar melts in nature.

This paper presents new evidence for fluorine enrichment in the diamond-forming mantle of the Siberian Craton. For the first time, we have discovered inclusions containing calcium and aluminum fluorides in diamonds from placers in the northeast of Siberia. In contrast to microinclusions in fibrous diamonds and coated diamonds, the inclusions we studied in diamonds from the northeastern Siberian Craton placers can be interpreted as fluoride melts. In diamond ISTD-119, inclusions are oriented parallel to the octahedron faces and can be considered syngenetic. At the same time, in diamond ISTD-124, an elongated inclusion is oriented parallel to slip lines. This provides grounds to believe that the formation of the inclusion was synchronous with the stage of diamond deformation. In variety V diamonds XLS-147 and ISTD-193, the morphology of inclusions located in the central parts of the crystals allows them to be interpreted as healed fractures. Within the inclusions, fluorine is present as compounds with calcium, having stoichiometry close to fluorite. The inclusions exhibit areas consisting of calcium fluorides and areas consisting of carbonates and/or iron oxides. In variety V diamond XLS-147, aluminosilicate inclusions and inclusions consisting of aluminosilicate and fluoride parts were identified. However, unlike inclusions in diamonds ISTD-119, ISTD-193, and ISTD-124, the fluoride part of the inclusions in diamond XLS-147 is represented by aluminum fluorides. There is a body of evidence for the growth of type V diamonds in a subduction zone. The compositional variations of the inclusions we studied indicate immiscibility of fluoride melts with aluminosilicate and carbonatite melts. The inclusions we have investigated testify to a fluorine-enriched diamond-forming mantle of the Siberian Craton at the time of diamond formation.

A thermodynamic model of the interaction between surface waters and the wastes of flotation enrichment of sulfide PGE–Cu–Ni ores from the ore region under consideration (Krasnoyarsk krai) is presented. The relevance of the study is determined by the need to assess the long-term stability of mineral associations. The aim of the work is to establish the patterns of transformation of mineral associations during long-term storage. The initial information was provided by mineralogical and chemical composition of samples from two pits, as well as the chemical composition of water extracts [Starostina et al., 2025]. Calculations were carried out in the solid–water–gas system under variations of Eh, simulating different degrees of system openness to atmospheric oxygen (standard T–P, pCO_2(gas) = 10^–3.5 atm). Based on the modeling results, it was found that pyrrhotite is stable under extremely reducing conditions (pO_2(gas) = 10^–79 atm), where the dissociation of water into atomic oxygen and hydrogen may occur. In general, the obtained models reflect the transition from sulfide to oxide–silicate associations with a decrease in the number of mineral phases as oxidation progresses. The modeled associations correspond well with mineral parageneses observed in polished sections. It was shown that the material retains its primary mineral structure even after decades of storage, which is explained by the high content of rock-forming minerals within a dense clay matrix that prevents oxygen and moisture from penetrating in amounts sufficient for intensive oxidation. The results obtained are recommended for use in the development of technological schemes for the recovery of potentially valuable metals from the flotation wastes of sulfide PGE–Cu–Ni ores.

This study synthesizes petrochemical, geochemical, and isotopic (Sm–Nd and Rb–Sr) data on granitoid and gabbroid complexes of the Western Sayan, formed in a range of geodynamic settings (including island arc, accretion–collision, transform–shear, and active continental margin environments) between the Late Vendian and Late Devonian. The results provide constraints on the physicochemical conditions of parental melt generation, the nature of magma sources, and their temporal evolution throughout successive geodynamic stages.

These findings highlight the long-term evolution of magma sources in response to changing geodynamic regimes during the Vend–Paleozoic development of the Western Sayan. The intrusive complexes display a systematic decrease in ɛNd and increase ⁸⁷Sr/⁸⁶Sr₀ values in granitoid and gabbroid complexes from early to later geodynamic stages: island arc (545–524 Ma, ɛNd = +7.5 – +4.9, ⁸⁷Sr/⁸⁶Sr₀ = 0.7042–0.7056), accretion–collision (505–460 Ma, ɛNd = +6.9 – +0.6, ⁸⁷Sr/⁸⁶Sr₀ = 0.7036–0.7041), transform–shear (437–433 Ma, ɛNd = +8.4 – +7.2, ⁸⁷Sr/⁸⁶Sr₀ = 0.7031–0.7057), and active continental margin (425–370 Ma, ɛNd = +5.7 – +1.0, ⁸⁷Sr/⁸⁶Sr₀ = 0.7035–0.7103). This progressive shift reflects a declining contribution of mantle sources (island-arc and oceanic types) and a concomitant increase in the role of ancient crustal components (metamorphic complexes, turbidites, and flysch-type sediments) in the generation of parental magmas.

The composition of volcano-terrigenous formations and age of detrital zircon from the tuff-turbidite series sandstones of the Dzhida zone of the Central Asian Orogenic Belt were studied. The sandstones of this formation, in terms of their mineralogical and petrochemical characteristics, correspond to feldspar graywackes and belong to the rocks of the first sedimentation cycle. The main volume of detrital material is represented by volcanics and, to a lesser extent, plagioclase grains. Relatively low values of chemical index CIA (58-68) indicate moderate or weak chemical weathering of lithic components, that is a low maturity degree of the detrital material formed due to the source rocks mechanical destruction. The distribution curve of U-Pb ages of zircon from sandstones of the tuff-turbidite series has a bimodal character with peaks at 530 Ma and 510 Ma. The studied rocks do not contain zircons of Neoproterozoic age. The greywacke composition of the studied rocks, the low maturity degree and the distribution of zircon grains U-Pb ages suggest the formation of these rocks in the forearc basin conditions due to the removal of material from local sources – Early Cambrian volcanic rocks of the Dzhida ensimatic island arc.

The effect of a gas curtain, formed by the destruction products of thermal protection elements in the combustion chambers of solid-propellant gas generators, on the material degradation of critical-section liners is investigated. Experimental data from two series of fire tests conducted on test benches are analyzed: one series performed by the authors and another reported in the literature. Both test series yield relatively low linear material loss rates, measuring 2.5 and 6 times lower, respectively, than those calculated using methods for large-scale solid-propellant rocket motors. A mathematical model is proposed based on the coupled solution to integral momentum and energy equations for the boundary layer and on the determination of the thermal state and failure of materials. This model allows for the introduction of additional admixtures of a cold gas, which is chemically inert with respect to carbon, into the fuel combustion product flow. The applicability of the model is validated by comparing simulation results with experimental data, with discrepancies not exceeding 5%.

Nekrasov matrices, as a subclass of H-matrices, exhibit unique functionalities and hold significant importance in diverse fields. These matrices are characterized by their distinctive structure, which endows them with numerous remarkable properties. This paper extends the study of Nekrasov matrices by introducing a new subclass of H-matrices, termed DN-matrices, and explores their properties, particularly focusing on the Schur complement.

In this paper, we consider two-dimensional multi-term time-space fractional diffusion-wave equations. We develop an alternating direction implicit (ADI) spectral method based on Legendre spectral approximation in space and finite difference discretization in time. We also prove the numerical stability and convergence of the developed scheme and that the error is O(τ²+N^γ-r), where Ν,τ,γ,r are the polynomial degree, time step size, Riesz derivative order and the regularity of the exact solution, respectively.

A continuous-discrete stochastic model describing the dynamics of a spatially heterogeneous population is presented. The individuals of the population are located in a system consisting of two interconnected compartments. The individuals move between the compartments along unidirectional pipes. The duration of individual motion along the pipes is specified by constants or functions depending on time. The individuals located in the second compartment can contact one of the reproduction centers located in this compartment. As a result of contact with a reproduction center, an individual begins the process of fission. The reproduction of the individuals arising due to fission occurs until the number of descendants exceeds a threshold level, otherwise the reproduction of individuals ends. The population formed after the completion of fission contains descendant individuals that are not subject to fission and leave the system over time. The assumptions of the model are formulated, a probabilistic formalization of the model and an algorithm of numerical modeling based on the Monte Carlo method are given. The results of a computational experiment to simulate the dynamics of the population depending on the parameters of the model are presented.

For an isotropic random field a simple computer-efficient grid model is developed which provides sufficiently high accuracy of solutions to stochastic transport problems for small correlation lengths. Results of test estimation of the time asymptotics of mean particle flux in a random multiplying medium are presented.

In this paper, we explore a double-step method for solving nonlinear equations containing a differentiable and non-differentiable operator. Our approach is built upon a combination of three different methods. We have analyzed the local convergence of the suggested method, considering both Lipschitz and L-average conditions & established the superquadratic (≈ 2.414) order of convergence. Finally we have pictured numerical results in comparison with several existing methods.

The paper considers an algorithm for numerical solving of a one-dimensional inverse magnetotelluric sounding problem. The algorithm is based on a special type of algebraic equation which is called a pseudo-quadratic equation. The inverse problem is considered in three variants: 1) for media with fixed geometry; 2) for media with fixed geoelectrical properties; 3) general case. Additionally, an algorithm is proposed for input data processing which provides the existence of a solution to the inverse problem. Numerical experiments realized on test media with different sets of parameters are carried out to study and illustrate the efficiency of the proposed algorithms.

The paper is devoted to modeling the propagation of seismic waves in a chemically inert elastically deformable rock. Only changes in stress and pore pressure are considered, and the chemistry of the saturating pore fluid does not directly affect the deformation of the rock. Chemical effects are taken into account by changing pore pressure and rock deformation in the transport equations. In the numerical solution of the problem under consideration, an algorithm is used to combine a Laguerre integral transform method and a finite difference method. The paper presents results of modeling of the transport of a dissolved substance through a semi-permeable clay shale.

The parameters for arsenic removal from Dashkesan ore enrichment tailings, which contain cobaltine (CoAsS), erythrite (Co₃(AsO₄)₂⋅8H₂O) and arsenopyrite (FeAsS), by combustion method with soda (Na₂CO₃) have been investigated. The processing method consists of two stages: 1) tailing/soda/coal mixture (molar ratio 1 : 1 : 0.2) was combusted at temperature 750 °C and time (1-3 h), 2) the combusted material was dissolved at 90 °C for 1 h in water with a phase ratio of S/L = 1 : 5. It was shown that the amount of As₂O₃ decreased from 5.47-6.19 to 0.52-0.71 wt%. The change of arsenic-containing phases in raw materials and processed products were studied by XRD, SEM/EDS and DTA/TG analysis methods. As the results of XRD analysis, the following arsenic-containing phases have been found in the combusted material obtained at 750 °C: sodium arsenate (Na₃AsO₄), sodium oxoarsenate (Na₅AsO₅) and scorodite (FeAsO₄⋅2H₂O). The residue obtained after dissolution is enriched with cobalt (CoO - 4.43 %) and can be considered as initial raw material for cobalt extraction.

The chemical composition of the fluff of Scheuchzer’s cottongrass (Eriophrum scheuchzeri Hoppe) is investigated, and its practical applicability as an alternative to cotton-containing plant raw material for the production of cellulose ethers and esters on its basis is assessed. It is shown that the fluffiness of the cottongrass seeds is 40.5 %, the average length of cellulose fibre is 10-25 mm, the mass fraction of hard-to-hydrolyse polysaccharides is 59.0±0.6 %, cellulose - 40.5±0.7 %, lignin - 25.8±0.3 %, water-soluble substances - 14.5±0.5 %, extractive fat-soluble substances (oil content) - 14.3±0.3 %, ash content - 5.0±0.6 % of the fluff mass. The degree of cellulose polymerisation is 1510 units, the mass fraction of α-cellulose is 84±1 %. In the composition of ash substances, there was no accumulation of noticeable amounts of heavy metals. The composition of ash substances is mainly represented by, rel%: potassium oxides (44.5), the compounds of phosphorus (18.7), silicon (15.2), calcium (9.6), magnesium (4.5), sulphur (3.1), and chlorine (1.53). Based on the conducted studies, a preliminary conclusion was made about the potential suitability of this kind of plant raw material for economical use.

A brief characterisation of helium is presented, the global reserves of this chemical element are analysed, and the structure of its consumption and production dynamics on the global market are considered. The increasing production and consumption of commercial helium, as well as the high industrial potential of helium products at the territory of Russia, necessitate the development of a set of technological solutions to improve helium extraction, its storage and processing. An analysis of membrane gas separation applications is presented, along with a comparative evaluation of this method against the traditional cryogenic distillation technology. The membrane unit is characterised by energy efficiency, compactness, simplicity of technological maintenance and process control, and does not require significant capital or operational costs. The types of filter cartridges used and the main technological schemes for producing helium in the gas industry are reviewed. Depending on the intended use plan for the helium products at the Markovskoye natural gas and condensate field (the Irkutsk Region), the use of combined technology (two-stage membrane separation with and without recycle, with additional fine purification units for helium concentrate) is proposed. The economic efficiency and commercial value of the proposed technological solution are substantiated.

Over the two recent decades, ionic liquids have become a focus of intensive research in the field of green chemistry. One of the recently developed application areas for ionic liquids is their use in agrochemistry as regulators and stimulators of plant growth, promoting an increase in crop yields and improvement of crop. In this review, research results in the area of using ionic liquids as herbicides, fungicides, antimicrobial agents, detergents, plant immunity inducers enhancing resistivity against phytopathogens, and plant growth stimulators. The advantages and disadvantages of ionic liquids in comparison with commercial products are described. The achievements and outlooks for the application of ionic liquids in agriculture are described, along with the possibilities to use them as multifunctional biologically active substances.

The data on complex metabolite profiling of Dracocephalum nutans L. of Lamiaceae family obtained using the analytical platform of gas chromatography with mass-selective detection are presented. The products of basic metabolism, phenol compounds, as well as mono-, sesqui-, and triterpenes were detected in the composition of metabolic pool. The main components of Dracocephalum nutans essential oil are germacrene D and B, (E)-caryophyllene, α-humulene, β-elemene, hexahydroxyfarnesylacetone and bicyclogermacrene. Oleanolic, ursolic, corosolic and maslinic acids, as well as rosmarinic acid, salvianic acid A (danshensu) and a number of other biologically active compounds were found in the methanol extracts. To describe the results of such non-targeted profiling, the term “molecular resource” is proposed.

The North Crimean Canal (NCC) is an irrigation and water supply canal built in 1961-1971 to provide water to low-water and arid areas of Crimea. The canal waters are used for economic purposes, so investigation of the processes that were formed after the destruction of the Kakhovka Reservoir in 2023 and currently occur in the watercourse is urgent. In this work, we determined the concentrations of hydrocarbons (with safety assessment), features of the distribution of n-alkanes, potential sources of their income in the water and bottom sediments of the canal and adjacent water areas. The total concentrations of hydrocarbons and separately n-alkanes were determined by gas chromatography. Exceedance of the maximum permissible concentrations of hydrocarbons in water (0.05 mg/L) was detected in 50 % of samples in 2024, independently of sampling territory and time. The hygienic standard of hydrocarbon content (0.1 mg/L) was not exceeded in any sample, which makes the water suitable for drinking water supply. In all the bottom sediment samples collected in the canal in 2024, the standard level of HC content (50 mg/kg) was exceeded. Conditionally clean bottom sediments were detected only in the Biyuk-Karasu River bed. The genesis of hydrocarbons in 2024 in the waters of the canal and adjacent areas was mixed, mainly biogenic. The molecular composition of n-alkanes in the bottom sediments of the canal corresponded to the mixed origin of hydrocarbons with the predominance of allochthonous components.

In the studies of various kinds of biological activity of sulphur-containing monoterpenoids, we previously revealed a practically promising leading compound, the product of the reaction of limonene-(+)-1,2-oxide with methylmercaptoacetate. In the present work, investigation of the antioxidant and membrane-protecting activity of this leading compound is presented in comparison with the starting structures for its synthesis: limonene and limonene-1,2-oxide. For the studies of antioxidant activity, erythrocytes from the blood of laboratory animals were used as a cell test system, and a heterogeneous substrate based on the brain homogenate of laboratory animals was the non-cellular test system. Membrane-protective activity was studied under the conditions of Н₂О₂-induced hemolysis and with oxidative stress induction by 2,2'-azobis-(2-amidinopropane)dihydrochloride. It is shown that all the three compounds exhibit statistically significant antioxidant and membrane-protective activity in both test systems. The most active compound is the leading one, thioterpenoid with the methylmercaptoacetate fragment. In order to expand the synthesis possibilities of monoterpenes of menthane series in thiating reactions, and develop the approach to the synthesis of new potentially bioactive thioterpenoids, the pharmacophoric methylmercaptoacetate fragment was introduced into the structure of limonene dioxide and carvone. The reaction of limonene with methylmercaptoacetate in a basic medium resulted in obtaining a bicyclic product of intramolecular cyclisation participated by the OH group at isopropenyl fragment. The reaction of carvone with methylmercaptoacetate under acid catalysis occurred regioselectively, with the formation of terpene sulphide at the endo-cyclic double bond. The crystal structures of the two latter terpene sulphides were studied by X-ray diffraction. Both thioterpenoids in the crystals under investigation are represented by only one enantiomer.

The chemical composition of volatile organic compounds emitted by tropical and subtropical plants representing four families Begoniaceae, Liliaceae, Myrtаceae, Moraceae used in indoor landscaping are investigated. Seven species and one interspecific hybrid are studied. The sampling procedure has been developed to provide concentrating the organic substances from air onto a specially treated sorbent placed in sampling tubes. The composition of volatile organic compounds was determined by high performance liquid chromatography. The compounds were identified using the spectrophotometric mode and witness method. The compounds detected in the volatile emissions of plants included carbonyls (aldehydes and ketones), carboxylic acids, as well as normal and branched hydrocarbons. The composition of emitted compounds and their ratios were determined to depend on the phases of plant development. The data on the composition of volatile organics were compared with the data on the seasonal variations of antibacterial and antifungal activity of these plants against test microorganisms Escherichia coli, Staphylococcus epidermidis and Candida albicans. Among exometabolites, the compounds that can enhance the phytoncide action have been detected. Thus, an increase in the activity of gaseous emissions of plants against E. coli was determined to be accompanied by the appearance or a sharp increase in the concentration of furfural derivatives, in particular 5-methylfurfural, 5-hydroxymethylfurfural, while an increase in the activity against C. albicans coincided with the appearance of o-methoxybenzaldehyde in volatile exometabolites. The possibility to use the studied species of decorative plants to improve the indoor air quality was assessed.

The content of total ash, ascorbic acid, tannins was determined in the leaves and flowers of Hemerocallis species: H. citrina, H. fulva, H. lilio-asphodelus, H. middendorffii, H. minor, cultivated under the conditions of the forest-steppe zone of the Novosibirsk Region. Biochemical parameters were determined during the flowering period in 2022. It has been found that the concentration of tannins, ascorbic acid, total ash in the leaves is 1.3-1.5 times higher than in the flowers. The leaves are distinguished by the highest content of ascorbic acid (11.43-16.35 mg/100 g). The specificity of the content of these substances in plants depending on the species, vegetative and generative organs during the flowering period is noted.

The paper presents the results of creating a new oil-displacing composition based on the ternary system of deep eutectic solvents (DES) “pentaerythritol - urea - choline chloride” with surfactants, and the results of laboratory tests of its effect on the filtration characteristics of the heterogeneous formation of the Usinskoye field with heavy and high-viscosity oil. As a result of studying the physicochemical characteristics and phase equilibrium of the ternary DES system, a new oil-displacing composition of prolonged action was created, based on the ternary DES system “pentaerythritol - urea - choline chloride” and surfactant, applicable for various geological and physical conditions of fields, in particular in the Arctic zone of the Russian Federation. The effectiveness of the composition was assessed for sections of the field at the early and late stages of development. It has been established that the use of the composition based on DES and surfactants leads to the equalisation of filtration flows with an increase in formation coverage, restoration of the initial permeability and, as a consequence, to a significant increase in the oil displacement coefficient at both low and high temperatures.

Maintaining a stable content of phenylpropanoids (rosavins: rosavin, rosarin, rosin, and cinnamic alcohol) and phenylethanoids (salidroside and tyrosol) in line with pharmacopoeial standards remains a critical challenge for scaling up the cultivation of Rhodiola rosea L. to meet global demand. One possible cause of low compound levels is the inadequacy of current standardisation methods for raw materials and preparations of Rhodiola rosea. This study aimed to identify the optimal drying temperature for raw materials from even-aged clonal plants of Rhodiola rosea cv. ‘Mattmark’. Results showed that higher drying temperatures reduced phenylethanoid levels, with room-temperature drying is optimal. In contrast, the maximal concentrations of rosavins, mainly rosavin, were detected at increased temperature (80 °C). Analysis of the relative distribution of phenylpropanoids revealed that higher drying temperature causes an increase in the proportion of rosavin and a decrease in cinnamic alcohol content, while rosarin and rosin levels remained stable. It has been shown that rosavin is the dominant phenylpropanoid independently of temperature. Thus, drying rhizomes at 80 °C enhanced rosavin content by 20 % but significantly (by a factor of 1.5-2) reduced total phenylethanoids. Therefore, drying at room temperature is recommended to maximise the total phenylethanoid and phenylpropanoid content in the raw material.

The elements of D. I. Mendeleev’s Periodic System (Mendeleev’s Table) have the relative atomic weight calculated as the average value of the atomic weights of several isotopes. The number of these isotopes is quite large; however, there is a lack of convenient and accessible systematisation for practical work. This article proposes a method and a device for such systematisation.

Antimicrobial resistance (AMR) constitutes one of the foremost threats to global public health in the XXI century: according to the data of the World Health Organization for 2025, one of the six laboratory-confirmed bacterial infections exhibits resistance to standard antibiotic therapy, with annual resistance rates increasing by 5-15 % across more than 40 % of pathogen-antibiotic combinations. Amid the declining efficacy of single-target antibiotics, the development of multitarget hybrid antibacterial agents - single molecules incorporating two or more pharmacophoric moieties capable of simultaneously engaging distinct bacterial targets - has gained critical relevance. This review systematically outlines the principal strategies for designing such hybrids: linked, fused, and merged pharmacophores. It also addresses key pharmacokinetic and toxicological considerations, limitations inherent to conventional combination therapy, and the advantages conferred by hybrid molecules, including a unified pharmacokinetic profile, elimination of chemical incompatibilities between components, and simplified dosing regimens. Particular emphasis is placed on the mechanisms of action of hybrid compounds. Several reviewed hybrids demonstrate low minimum inhibitory concentrations, reduced frequencies of spontaneous resistance emergence, and favourable fractional inhibitory concentration indices (FIC ≤ 0.5), underscoring the therapeutic potential of this approach. Some examples of compounds are highlighted for their potent activity against diverse resistant bacterial strains and biofilms. A number of hybrid compounds have successfully advanced through clinical trials (TNP-2092, TNP-2198, cefilavancin, DNV-3837).

The toponyms of the Lena River basin, represented by hydronyms and oikonyms, are considered. To conduct an analysis of the classification of toponyms, geographical toponymic dictionaries, special regional studies, popular science, reference, encyclopedic and educational literature, materials from the periodical press and the media were used. A database of geographical names of significant tributaries, large lakes and settlements was compiled based on the sources used. The analysis of the information entered the database was carried out according to the classification of toponyms. The following semantic classification was used for the etymology of the identified toponyms (names reflecting natural conditions and processes; anthropotoponyms; production toponyms; trade and transport; toponyms indicating types of settlements; ethnotoponyms; memorial toponyms; religious and cult toponyms, etc.). The language classification reflects the settlement of peoples along the Lena River basin, where Tungus (Evenki and Even) toponyms are more common in the upper and lower reaches of the river, Yakut names are present in the Middle Lena, Russian names are mainly in the territories of the Zabaikalski Krai, Irkutsk Oblast and Amur Oblast. Classification by objects of toponymic nomination showed the prevalence of hydronyms (limnonyms and potamonims). A series of thematic maps was compiled, displaying the spatial distribution of toponyms of the Lena River basin, toponymic information. The sources for compiling the maps were publicly available topographic maps of scale 1:100 000, 1:200 000. The created GIS database and toponymic maps made it possible to systematize different types of toponyms identified in the territory of the Lena River basin to visualize their spatial distribution.

Process-based estimates of the hydrological consequences of the natural and anthropogenic components of climate change in the Selenga River basin were obtained based on the ECOMAG hydrological model and data from the CMIP6 ensemble of Earth system models. The aim of the study was to determine the impact of anthropogenic climate change on the river runoff formation of during the long low-water period of 1996-2017 and to provide forecast estimates for the near future of the 21st century. For this purpose, calculations were carried out using a physically-based model of runoff formation, previously verified against observational data, using two implementations of Earth system models: considering only the natural oscillations of the climate system and external impacts of natural origin, and considering the impact of anthropogenic activity, expressed in an increase in greenhouse gas emissions, including according to SSP scenarios for the future period. Warming in the summer period of 1996-2017 led to an increase in total evaporation, which, together with a decrease in the amount of precipitation and an increase in runoff losses due to infiltration, led to a long-term low water content of the Selenga. Under natural climatic conditions, the annual runoff of the Selenga in 1996-2017 should have been 28 % greater, including the spring flood runoff by 10 % and the summer-autumn runoff by 30 %. In the near future, on average by 2040, under scenarios SSP2-4.5 and SSP5-8.5, a decrease in the annual runoff of the Selenga by 9-25 % is likely, especially in the summer-autumn period.

The article examines the specifics of demographic processes in the Irkutsk agglomeration against the background of the regional situation. In the context of the theories of the second demographic transition and the second stage of the epidemiological transition, authors analyze the features of fertility and mortality in large and small cities and the suburbanized zone of the agglomeration. Based on the features of the age composition of fertility and mortality, the authors show the existence of three types of population reproduction in the onesomes space of the agglomeration: in a small town, large cities and suburbia. The first type was formed during the period of mass Soviet urbanization in the mid-20th century, the second - at the turn of the 21st century as part of the second demographic transition. The latter combines two oppositely processes: a decrease in mortality and an increase in life expectancy as part of the second stage of the epidemiological transition and an increase in the birth rate of migrants from the city while maintaining in general its urban age structure.

The article describes the development of an online cartographic service for the rapid assessment of the quality of the urban environment within urban agglomerations. The server being created allows users to obtain information about the quality of the urban environment at a selected point based on a customizable set of criteria. The paper describes a methodology for forming an index of the quality of the urban environment, which includes an assessment by various groups of criteria, such as climatic, social, environmental conditions, transport infrastructure, etc. For each criterion, a rating method is used, which allows forming a final index. The territory of the Irkutsk urban agglomeration was chosen as the object of the study. The work describes the stages of creating a service, including collecting and processing data, developing algorithms for calculating indices, creating a website based on a geoportal. As an example, the calculation of the index of accessibility of comprehensive schools and proximity of industrial enterprises is considered. The created system will make up for the lack of services for rapid assessment of the quality of the urban environment and will become available to a wide range of users, including professionals and ordinary citizens, will make it possible to use extensive data for assessment.

Various factors affecting the housing market in the Irkutsk urban agglomeration, both for urban areas and for peri-urban area are evaluated and systematized. The research was based on the open data of the site CIAN 2024. Evaluated the statistical relationship between housing prices and factors of density of greenery, density of social infrastructure, transport accessibility and the presence of factors of negative and positive neighborhood in suburban and urban areas. It was found that for large Siberian agglomerations center-peripheral and coastal price differentiation is characteristic. Irkutsk agglomeration is characterized by higher population growth due to suburbia and the imbalance of housing affordability in the city: the largest population growth was recorded not only in the most attractive urban areas with high housing prices, but also in areas with low, middle-price areas are growing noticeably slower. The study showed fundamental differences in the differentiation of housing prices in urban and suburban areas. It was concluded that for urban areas the most important is the density of social infrastructure and transport accessibility, the criminal environment and the least - ecology and greening. In the peri-urban area, the most important factors are the type of permitted use of land (which is primarily related to the availability of engineering infrastructure), transport accessibility, natural and environmental factors (proximity of objects of negative neighborhood).

Landscape-hydrological zoning and mapping of the Central Ecological Zone of the Baikal Natural Territory has been performed in accordance with the runoff-regulating functions of landscapes, which determine the transformation of precipitation into surface and groundwater runoff, conditions for the redistribution of runoff seasonally, reduction of peaks of floods and improvement of water quality. The runoff-regulating level of landscapes is determined by the structure of the vegetation cover, the structure of the soil-ground layer and morphological characteristics. These structural parameters determine the environmental protection and water-ecological functions of the natural complex, which are expressed in water protection, soil protection, anti-erosion, anti-avalanche and other properties of the territory. Orographic elements and types of landscapes play a leading role in the spatial landscape-hydrological differentiation of the territory. The individual landscape-hydrological characteristics of the natural complexes of the districts are substantiated by a comprehensive analysis of forest-growing and geo-morphological features, structural and typological characteristics of soils. The purpose of zoning is identify natural complexes with various landscape and hydrological functions that reflect the intensity of drainage, water-ecological potential and environmental conditions of the territory. The performed zoning of the Central Ecological Zone of the BNT is based on the analysis of cartographic, analytical and expedition materials, as well as the results of previously performed landscape-hydrological, geo-morphological and soil studies within the boundaries of the Baikal natural territory. The constructed landscape-hydrological map shows areas with different morphological, soil-vegetation and hydrological conditions. These natural conditions characterize the level of runoff regulation, the intensity of soil migration of matter, the danger of erosion and mudflow processes, and, as a result, show areas with different environmental protection and water-ecological properties.

The work is based on field landscape-geochemical and office analytical studies conducted in 2015-2024 on the coast of Lake Baikal and the adjacent territory. Samples of surface water and soil were collected at key sites, and chemical and physicochemical analyses were carried out in the field and laboratory conditions of the V.B. Sochava Institute of Geography, Siberian Branch of the Russian Academy of Sciences (IG SB RAS) using standard methods. Increased contents of F^-, NH₄⁺, PO₄^3-, Pb, Ni and oil products were found in surface waters near populated areas on the coast of Lake Baikal, exceeding the MAC values. The main anthropogenic sources of environmental pollution are: construction and road enterprises, thermal power plants, boiler houses, railway and motor transport, waste dumps. The sources of surface water pollution with phosphates and ammonium are housing and communal facilities. In the soils of the coast of Lake Baikal, local high content of Mn, Pb, Ni, Co, Cr, Zn, Cu was found, exceeding the MAC near the settlements of Listvyanka, Baikalsk, Bolshoe Goloustnoe, Sarma, Kabansk, Turka, Ust-Barguzin, Severobaikalsk and Nizhneangarsk. The maximum concentrations of chemical elements in soils in relation to the background also have: Ba, Sr, V and oil products, but do not exceed sanitary and hygienic standards. High concentrations of HM in coastal soils are possibly associated not only with anthropogenic sources, but also with deposits of rare metals.

The problems of mapping the relief of deep-sea surfaces are mainly associated with the impossibility of obtaining data on the geological structure of the discovered forms, which often makes it difficult to unambiguously determine their genesis. The paper provides examples of using additional information to increase the reliability of conclusions about the relief of the bottom surface of a deep-sea basin. To clarify the genesis of the bottom forms of the Baikal Basin, published data from seismic and geophysical studies of the bottom surface, and core drilling materials were widely used. As a result of the analysis of the obtained material, the genesis of the remnants on the underwater slope of South Baikal was established, and it was found that the sharp turns of the valleys of some canyons are explained by the lithological, structural and textural features of the slope deposits.

To study the adaptive capacity of crop production under changing climatic conditions, a database of spatiotemporal characteristics of hazardous and adverse natural-climatic events during the warm season has created at the Laboratory of Geoecology and Geosystem Dynamics at the Institute of Monitoring of Climatic and Ecological Systems the Siberian Branch of the Russian Academy, for the southern taiga of Western Siberia. The components of the database, its structural features, and its capabilities of spatial assessment and cartographic visualization of the studied phenomena which it allows are shown. Based on the analysis of meteorological data from 32 stations over the last 20-year period, a series of thematic and integrated maps illustrating the territorial and temporal patterns of hazardous and adverse natural-climatic events have been created within a GIS environment. Intra-regional patterns in the intensity, frequency, and duration of these events were identified. Statistical assessment and mapping have revealed that climate-induced risks to the local crop production system are not decreasing and that their spatiotemporal patterns are heterogeneous. The highest risks for plant growing occur during the spring season and are associated with the hazardous phenomenon of late spring frosts. During the summer, climatic hazards in the northeast of the region are associated with intensive precipitation, while in the southwestern they are caused by hot weather. It has been noted that adverse events occur more frequently than hazardous ones and, in combination, create a high risk-forming potential. A detailed analysis of the spatiotemporal characteristics of the studied phenomena and the cartographic visualization of the results enable monitoring of developing hazardous situations, risk forecasting, and the formulation of recommendations for minimizing losses in crop production.