Home – Home – Jornals – Philosophy of Sciences 2024 number 1

Investigations (mainly those performed by the authors) of air blowing through a perforated section on a body of revolution with a large aspect ratio in an axisymmetric incompressible flow are summarized. Result of numerical and experimental studies of the flow properties, efficiency of the turbulent boundary layer control and prospects of using it for a body of revolution at small subsonic velocities equivalent to the take-off and landing regimes for a modern subsonic cargo aircraft are analyzed.

Optimization of tangential jet blowing on the upper surface of a supercritical transonic airfoil in the buffet mode was carried out. Two-dimensional Unsteady Reynolds Averaged Navier-Stokes equations were solved to simulate the flow past the airfoil. The Spalart-Almaras turbulence model was used to close the equations. The position of the slot nozzle and the intensity of the jet blowing out of it were varied. The optimal position for blowing with the minimum jet intensity to suppress buffet was determined.

This paper presents the results of a study of the influence of various sources of magnetic field on the size of droplets formed in microfluidic flows. Direct and reverse emulsions in a microfluidic device with flow focusing were obtained using magnetic fluids based on oil and water which are a continuous phase. Non-magnetic inclusions of various volumes were formed depending on the selected parameters: continuous phase flow rate, magnetic field configuration, and the position of the magnet relative to the axis of the device.

A periodic flow of an incompressible fluid around plates at large Reynolds numbers and small Keleghan-Carpenter numbers is considered. The energy dissipation over the oscillation period and the resistance coefficients of the plates are determined. Two-dimensional problems are studied on translational and angular vibrations of a flat plate and a plate in the shape of a circular arc, on translational vibrations of a circular cylinder with ribs symmetrically located on it, on angular vibrations of cruciform plates, as well as the problem of periodic flow around an inclined edge on a flat wall. A three-dimensional problem of translational and angular vibrations of a thin circular disk is considered. All obtained dependences for energy dissipation and drag coefficients are presented in analytical form through velocity intensity coefficients, which characterize the velocity singularity at the sharp edges of the plates with a potential flow around an ideal fluid. Some obtained dependencies are compared with the available numerical and experimental data.

Numerical modeling of a flow around a symmetrical thick drop-shaped airfoil in a non-stationary formulation was carried out at Reynolds numbers Re = 10⁴ ÷ 10⁵ and in the range of angles of attack α = –10 ÷ 10°. The calculations were performed in the approximation of the unsteady Reynolds-averaged Navier-Stokes equations (URANS) using the implicit large-eddy method (ILES). In the URANS approach, the position of the laminar-turbulent transition was determined based on the models k–kl–ω, k–ω–γ–Re_θ (Menter model) and (k–ω)-SST models with a given laminar flow region. It is shown that the position of the laminar-turbulent transition region has a significant impact on the flow structure and aerodynamic characteristics of the airfoil. Comparison of the results obtained using the ILES approach with experimental data showed that they are in good agreement. URANS calculations did not allow obtaining results consistent with experimental data. Fixing the laminar-turbulent transition point in the URANS calculation in some cases made it possible to correct the results.

Ceramic composites based on B₄C with a mole fraction of CrB₂ 0-30% were obtained by reactive hot pressing of a mixture of B₄C, Cr₂O₃, and nanofibrous carbon at a press force of 17.5 MPa, a temperature of 2000 °C and an exposure time of 10 min. The possibility of the chemical reduction reaction of metal oxide with boron carbide during hot pressing was studied. During the synthesis of CrB₂, the density of B₄C was found to increase due to the formation of the CrB₂-B₄C eutectic liquid phase. The relative density of all B₄C-CrB₂ composites obtained under these conditions exceeds 90%. The dependences of the microhardness and elastic modulus of samples on the concentration of the plastic phase were obtained. The dependence of the elastic modulus of the heterogeneous material on the volume fraction of chromium diboride taking into account porosity was determined by sequentially using the Reuss and Voigt averaging schemes

Uniaxial tension and three-point bending tests were performed for polymer composite samples made of Crystal 85-5 epoxy resin modified with MHG-4E (average particle size 5-15 µ m) and FV-530D (average particle size 25 µ m) photoluminescent powders. The dependence of the elastic modulus on the filler concentration was obtained. The photoluminescent properties of the resulting composites were studied. The dependence of the has been established afterglow intensity on the filler content in the composite was determined.

A problem of mathematical modeling of a section of a fuel element (fuel element), including a number of fuel pellets and a shell fragment, in an axisymmetric formulation is considered. It is assumed that the shell is a thermoelastic-plastic body, and the tablet is a thermoelastic body, taking into account the cracking of the material. To numerically simulate the thermal and mechanical contact of tablets with each other and with the shell, various variants of the domain decomposition method were used. The results of calculations are presented, which describe the achievement of the nominal power of a section containing 10 pellets, the influence of cracking of pellets on the thermomechanical state of the fuel rod is assessed.

A new technique has been proposed and implemented that allows for time-frequency analysis of data obtained using the PIV method, taking into account the readings of the surface sensor of a hot-wire anemometer. The technique is based on calculating the correlation coefficients between the data obtained by the PIV method and the data from the hot-wire anemometer sensor, which were previously filtered in a given frequency range. Using this approach makes it possible to obtain data on the unsteady characteristics of flows throughout the entire measurement range in the frequency range, the boundaries of which extend beyond the boundaries of the frequency range of the PIV method. Using the proposed method, a study of non-stationary processes in the region of interaction of a shock wave with a boundary layer at the Mach number M = 1.43 was carried out.

The feasibility of joining of the 6061 aluminum alloy to double-layer oxygen-free copper (TU1) by laser welding technology is reported. The weld formation and microstructure of the Cu-Cu-Al welding joint for various technological parameters are analyzed. The assessment of experimental results is based on macro- and microstructure observations of the weld using the AxioObserver D1M and Gemini SEM 300 scanning electron microscopes. The width and depth of the molten pool and the mechanical properties of the Cu-Cu-Al welding joint are tested by the Eagle-MD semi-automatic image measuring instrument and the YH-9002 computerized tension and compression machine. Among the nine tested samples, the most favorable weld parameters values are obtained with a laser power at 1600 W and a welding speed of 90 mm/s. The aluminum side area has a richer metallographic structure than the copper side area after welding.

Based on the solution of the cellular problem of the theory of elasticity, an analysis of the main types of deformation of the binder cross-reinforced with fibers of the composite was carried out. It is shown that all previously predicted possible types of local deformation of the binder fiber composite are revealed in numerical solutions of the cell problem of the averaging theory. The local stress-strain state of the binder significantly depends on the cross-sectional shape of the fibers. In the case of fibers with a square cross-section, it is possible to estimate the stress-strain state using explicit formulas, while for fibers with sections of other shapes, a computer must be used to calculate the stress-strain state.

It has been found that the heat release in the homogenized composite model is described by Joule-Lenz law for the averaged current strength and voltage. It has been shown that the local electric field strength and the local electric current in a real composite are usually significantly different from those in the averaged model despite the fact that the electric field potentials in the averaged model and the real composite are close.

Various crossovers of the effective permeability of certain analytically treatable models of the Darcy flow in porous media are studied. They account for the critical behavior as well for the regimes with low concentrations of obstacles. Transverse permeability of spatially periodic arrays of impenetrable cylinders is found in an analytical form and accounts for various asymptotic regimes. Longitudinal permeability for a square array of cylinders is found as well. Transverse flows past hexagonal and square arrays of cylinders are also considered based on expansions for small concentrations and lubrication approximation for high concentrations of cylinders. Three-dimensional periodic arrays of spherical obstacles are considered as well. Formulas for the drag force exerted by various lattices of obstacles are derived from low-concentration expansions. The Stokes flow through two-dimensional and three-dimensional channels enclosed by two wavy walls is studied by means of expansions for small waviness amplitudes. Compact formulas for permeability are derived in the form of factor approximants for arbitrary values of waviness. Various power laws are accounted for in the regime of large waviness parameters, as well as the existing expansions at small amplitudes.

The classical time-harmonic plane strain problem for a fluid-loaded cylindrical elastic shell is revisited. The results of the low-frequency asymptotic analysis, including explicit formulae for eigenfrequencies, are presented. A refined version of the semi-membrane shell theory is formulated. It is shown that the shell inertia does not affect significantly the lowest eigenfrequencies. It is also demonstrated that the ring stress component has a parabolic linear variation.

The effective thermal characteristics of composite materials used in the theory of solid-state cooling are studied. Two classes of composites are considered: layered structures consisting of a large number of nano-sized layers and two-phase granular composites. It is assumed that the boundaries between media are imperfect. At these boundaries, the temperature experiences a Kapitsa jump. The effective characteristics of layered structures are obtained using the matrix averaging method. The Averaging of the characteristics of granular composites is based on the Bruggeman approach. Formulas taking into account the influence of the Kapitsa interlayer resistance on the average thermal characteristics of the structure are obtained. Expressions for average values of heat sources are derived.

A method of transition from the three-dimensional piezoelastic problem for a composite material to the one-dimensional problem for a piezoelastic beam is presented. This is done using an asymptotic method of homogenization based on the separation of fast and slow variables in the solution. A special feature of the problem is the presence of two small parameters, one of which characterizes the microstructure of the composite material, and the other the cross-sectional size. Averaged relations describing the piezoelastic beam and fast correctors were obtained. Their joint use makes it possible to correctly describe the total stress-strain state of the initial three-dimensional body. The proposed method is suitable for solving the three-dimensional problem of deformation of an extended bodies with an arbitrary periodic structure and new problems (e.g., the torsion problem) that have no analogues in the theory of piezoelastic plates.

The stress-strain elastic field in a square array of N non-overlapping circular inclusions is described by approximate analytical formulas. In particular, soft inclusions are studied by an asymptotic analysis. The case with N = 1 yields a regular square array of disks of radius r embedded in an elastic matrix. The computations of Natanzon and Filshtinsky are based on an infinite system of linear algebraic equations solved by the truncation method. The infinite system determines the Taylor series coefficients of the Kolosov-Muskhelishvili complex potentials. A method of functional equations is used to write the series coefficients in symbolic form up to terms of the order of O ( r ^2s) at a fixed value of s . Approximate analytical formulas for local elastic fields are derived.

A small-sized elastic isotropic strip-beam loaded with variable body and surface forces is considered. On the front surfaces, surface shear stress and inertia are taken into account within the framework of the Gurtin-Murdoch surface elasticity theory. Asymptotically correct equations describing the long-wavelength bending deformation of micro/nano-beams taking into account shears and surface effects are derived by asymptotic integration of the two-dimensional elasticity equations over the strip thickness. The influence of surface stress and inertia on the lower spectrum of natural vibrations of metal micro/nano-beams is studied. It has been shown that surface inertia has the same effect on the spectrum of natural frequencies of bending vibrations as surface stresses.

The process of buckling of the von Mises truss in the case of material instability, i.e., with allowance for the loss of ellipticity, is considered. Strain diagrams are constructed. Results that allow one to study buckling of thin-walled structures (arcs or shells) made of materials for which the loss of ellipticity of equilibrium equations is possible are obtained.

The problems of indentation of a rigid stamp of finite dimensions with a surface microrelief into a multilayer elastic strip are considered. Boundary variational formulations of problems using the Poincare-Steklov operator, which maps contact stresses into displacements, are presented. When approximating this operator, a discrete Fourier transform was used; to calculate the transfer function, an algorithm based on the variational formulation of the boundary value problem for displacement transformants was used. As a result of approximation of the original contact problem, a quadratic programming problem with constraints in the form of equalities and inequalities was obtained, for the numerical solution of which an algorithm based on the conjugate gradient method was used. A number of patterns of contact interaction have been established.

The article begins a series of final author’s publications designed to evaluate Descartes’ contribution to the formation and development of the philosophy of the Modern Era. The subject of concern directly in this article is the totality of the components of Descartes’ worldview, scientific and philosophical positions in its integrity and structural specifics. Ten such components are identified, and six of them are worthy of special mention considering their subsequent primary development in the philosophy of the Modern Era. These are materialistic, objective-idealistic, subjective-idealistic, skeptical and irrationalistic components, as well as one more, which there is no reason to describe as directly and consistently dialectical, but which is nevertheless represented in Descartes by his concrete steps to form one that. Focusing here not only on these six components, but on their totality also makes sense. To be exact, this clearly shows that in Descartes, they form a unity in which at least the first six both exclude and condition each other. Whereas, in subsequent modern European philosophers each of this components is present primarily as a separate line, declared as perhaps the only acceptable and worthy of efforts to develop it. So, focusing on the total picture of Descartes’ views makes clear the structural integrity of the entire modern European philosophy in all the diversity of its main components.

The calculation of the Earth’s insolation with high spatial and temporal resolution made it possible to calculate solar characteristics reflecting changes in astronomical factors regulating variations in incoming solar radiation and changes in the intensity of radiative heat transfer (meridional, in the ocean-mainland system, and interhemispheric). Following this, the astronomical theory of climate change has been modernized on the Holocene scale. Based on the synchronization of global climatic events with extremes of solar characteristics in the Holocene and Late Pleistocene, a method of solar geochronology is proposed, which makes it possible to clarify the chronology of global climatic events and explain their origin.

In world science there are no approaches to identifying critical telecommunications infrastructure based on the concepts of human geography. The aim of our study was to develop such an approach and to test it using the example of a single fiber-optic network of the Russian Federation. The theoretical basis of the approach was the concept of economic and geographical location and its expansion in the form of info-communication and geographical location. This made it possible to estimate the position of any critical element through the parameters of the network formed by this element. In this context, critical telecommunications infrastructure includes nodes and communication lines, the accidental or intentional disconnection of which leads to the subsequent disconnection of other nodes and lines. It is proposed to distinguish between ordinary, critical, critically dependent and dependent nodes, as well as ordinary and critical lines. The methodical basis of the approach was the author’s algorithm for identifying critical nodes. The initial information was taken from the author’s database on domestic telecommunication lines and Rosstat data on the population of Russian cities as of January 1, 2022. One thousand one hundred and eleven out of 1117 cities were considered, since six cities were not connected to the single fiber-optic network of Russia. The implementation of the geographical approach made it possible to detect more than a hundred critical nodes (cities). The characteristics of the ten most critical nodes are given. The distribution of the number and population of cities across four types of nodes and federal districts of Russia has been carried out. It has been established that most of the critical lines are laid to small towns. The results obtained were discussed from the standpoint of research limitations, simulation of simultaneous disconnection of several critical elements and recommendations for laying new telecommunication lines. The practical significance of the results obtained may be related to the development of telecommunication measures to improve the stability of the fiber-optic network. Three directions of further research are proposed.

The purpose of the article is to summarize approaches and methods used abroad for estimating carbon emissions resulting from land use changes on global and regional levels. To understand the place of this topic in modern geoecology, an analysis of bibliometric indicators was carried out based on the Scopus аbstrаct and citation database. There has been a significant increase in publications on the research results of carbon emissions and removals under the influence of land use in the world since the early 2000s with over 200 articles published per year currently. The leading countries in terms of publication activity include China, the USA, Germany, Great Britain and Brazil, with the Chinese Academy of Sciences being the leader among organizations. The present-day research of carbon balance changes under the impact of land use change is based on the land cover change detection in the spatiotemporal aspect using advanced geoinformation technologies, and on modeling of carbon fluxes through the use of precise data consistent with the approaches 2-3 of the Intergovernmental Panel on Climate Change methodology. It has been established that most of the studies by leading scientific centers have common algorithm and stages. The article provides a description of these stages, namely the methods and specific tools used, as well as identifies their advantages and disadvantages. The general research algorithm includes, at the first stage, an assessment of the dynamics of land use/land cover change for different time spans, then carbon balance modeling as a result of land use changes, and development of regional policy measures on this basis. National peculiarities in application of methods and initial data are also revealed (cases of China, Brazil, etc.). It is concluded that it is necessary to further improve methods in the field of accuracy of land use/land cover classifications and timeliness of detecting its dynamics, as well as carbon stocks assessment. These factors determine the specific practical actions in the field of regional planning and the offset measures development under the climate policy.

The article highlights the factors and conditions for the formation of a regime of sustainable development of a territory with environmental management according to the criterion of completeness of the composition and functioning of geographical system ‘nature-economy-population’ of the territory. Completeness is a pass-through indicator of the optimality of systems of various kinds at the minimum and maximum levels of their existence and changes in the process of nature conservation, economic growth and improvement of society. The degree of completeness is a variant of the evaluation function that distinguishes geosystems of different locations and variable states by a set of interchangeable influencing factors of natural, economic and social origin and features of local conditions of the geographical environment. All the observed processes reflect the goal of striving for perfection in the form of completeness and safety of its systemic expression, for the ideal of existence, a priority development goal, only with the achievement and overcoming of which sustainable development is possible. The trends of completeness are distinguished as the upper and lower envelope lines (surfaces) of the diversity of the connection of data from field and statistical observations. Controlling additive influences shift the landscape norm of completeness of different locations. It is necessary to take into account special restrictions on the degree of incompleteness and overflow of system qualities. Models and methods of analysis are demonstrated by the example of restoration of forest plantations and the implementation of the investment process in the regions of Russia.

To solve the problem of assessing the external load on the Russian part of the Irtysh River from the catchment, the ILLM model was used. It takes into account the contribution of point and diffuse sources to the formation of the load and makes it possible to calculate the removal of impurities from the catchment. The model takes into consideration the influence of hydrological factors and chemical retention by the catchment and its hydrographic network. In order to provide the model with the necessary input information, classification of the underlying surface types has been performed using PROBA-V and Sentinel-2 satellite images. Data on the content of nutrients (N and P) and trace elements (Cu and Zn) in soil and river waters of the studied territory were collected and analyzed. Based on the processing of materials on the activities of more than 800 agricultural enterprises, the number of livestock, and organic and mineral fertilizer inputs were estimated, and the total nitrogen and total phosphorus inputs to the hydrographic network were calculated. The external load (including the diffusive component) of nutrients (nitrogen and phosphorus) and metals (copper and zinc) was assessed for both the entire Russian part of the Irtysh basin and for seven of its sub-basins, including the Tobol, Ishim, Om and Konda rivers. According to the calculation results, the contribution of the transboundary load to the outflow of the considered chemicals in the outlet sections of the transboundary rivers was evaluated. It is shown that the ratio of the contribution of different components of the external load to the outflow varies depending on the water content of a year.

The article presents the results of reconstruction of the long-term paleo-fire dynamics in the forest-steppe zone of Western Siberia (Novosibirsk oblast) using the example of the Nikolaevsky ryam peat thickness. According to the radiocarbon dating, the studied peat column has been formed during 3200 cal. yr BP from the Late Subboreal to the present. Twenty-one local fire episodes were identified and time of their occurrence, frequency and intensity were determined based on the macro-charcoal and radiocarbon analysеs. In addition, data on the dynamics of paleo-fires in the forest-steppe ryam were compared with published paleoclimatic reconstructions for the Baraba lowland. At the end of the Subboreal period, six pyrogenic episodes were identified with a peak of fire activity during 2850-2750 cal. yr BP at a rate of accumulation of charcoal particles of 370 particles cm²/year. Most of the fires occurred in the Subatlantic period, namely, 15 fire episodes with the largest local fire activity in the period of 1100-1050 cal. yr BP and the rate of accumulation of charcoal particles reaching 600 particles cm²/year. These paleo-fire peaks coincide with climate warming in the Baraba lowland, marked as an increase in the average July temperature and the predominance of forest-steppe phytocenoses in composition of vegetation cover of the Baraba. Wetter climate conditions and the spread of taiga vegetation from 2100 to 1700 cal. yr BP prevented the occurrence of fires in the territory of the ryam. In addition, during colder climatic periods, fires were either completely absent or of low intensity. When comparing the dynamics of paleo-fires of the Nikolaevsky ryam with paleoclimatic reconstructions, the influence of the climate change on the occurrence and intensity of pyrogenic episodes was revealed.

The purpose of this work was to analyze the state of Scotch pine forests polluted by technogenic emissions from the Irkutsk aluminum smelter (IrkAZ) from the moment it was launched to the present (more than 50 years). The level of the forest pollution was assessed based on the content of inorganic elements in the pine needles. The trees vital state was estimated using the life status index (LSI). A direct dependence of the vital state of pine stands on the dynamics of emissions from the IrkAZ was revealed. Thus, the rapid development of visual signs of needle damage (necrosis and chlorosis), an increase in the level of tree crowns defoliation up to 70 %, the appearance of drying trees in local areas near IrkAZ were observed in the late 1970s and early 1980s (period of maximum emissions, 90-100 thousand tons/year). The fluorine content in the needles reached 210 mg/kg of dry weight. LSI of trees did not exceed 2-3 points, which indicated a strong deterioration in the parameters of pine stands. The area of heavily oppressed tree-stands reached 20 thousand hectares. The level of technogenic emissions from IrkAZ decreased at the end of the 1990s, and the state of pine stands began to improve, LSI of trees increased to 4,9 points. In the last 5 years, the amount of emissions from IrkAZ has remained unchanged (about 35 thousand tons/year), the level of fluorine in the tree needles near the plant is quite stable (70-80 mg/kg of dry weight). LSI of trees has increased to 5,3 points, there are no drying tree-stands. The area of heavily weakened forests does not exceed 2 thousand hectares. Despite the positive dynamics in the change in the state of pine stands, further monitoring of their state is required to predict changes in sustainability of forests in the polluted areas of the region.

This paper presents results of field studies into the soil biota in conditionally undisturbed territories located in the northern part of Cisbaikalia (central ecological zone). This territory is characterized by high landscape diversity, which is due to the peculiarities of the relief and, associated with this, local climatic conditions. Thus in a relatively small area of the territory there are various geosystems from meadow-marsh to mountain-steppe. Soil zoocenoses are accordingly also diverse, and the structure of the population, the average number and biomass make it possible to evaluate communities by taxonomic diversity. This indicator characterizes not only the state of the soil mezopopulation, but also its resistance to external influences. In conditions of limited economic activity, this territory can be a kind of testing ground for comparative analysis and assessment of the restoration potential of soil zoocenoses. Taxonomic diversity was calculated using Margalef’s index, which makes it possible to link two characteristics, the abundance and the number of taxa per unit area. Based on the calculations obtained, five categories of taxonomic diversity of soil invertebrates (from very low to high) were distinguished. Taking into consideration the high landscape diversity of the territory, the spatial distribution of soil mezopopulation reflects the full range of zoocenoses in the region. The numerical characteristics of the mezopopulation of soils are influenced by the hydroclimatic conditions of the territory which, in turn, depend on the terrain. Results from investigating the soil mezofauna aimed at assessing the taxonomic diversity in the spatial aspect are intended to be used as a basis for cartographic modeling in the future.

The article presents the results of temporal and spatial distribution of aerosol particles and micro-admixtures included into them (polycyclic aromatic hydrocarbons, polychlorinated biphenyls) in the near-water layer of the atmosphere above Lake Baikal obtained during a ship expedition from July 18 to July 24, 2022. During the study period, in the lake near-water atmosphere, mainly low values of mass and number concentration of aerosol particles, and resistant organic pollutants (PAHs, PCBs) were observed compared to the fire hazard periods of 2016-2020. During the expedition, the PAHs content in the atmosphere varied from 0,071 to 2,6 ng/m³, which is lower than the concentrations established during the fires (0,22-133 ng/m³). Increased concentrations of the studied components were found only in some areas of Southern Baikal, where the formation of aerosol structure occurred due to local pollution sources situated in the populated near-shore areas (namely, Listvyanka, Kultuk, Slyudyanka, Baikalsk), and at the moment of transfer of polluted air masses northwestward to the lake from Irkutsk and Angarsk. In the aerosols samples from background areas, a PAHs group with two or three benzene rings dominated mainly by naphthalene and phenanthrene. Near local sources in the southern part of Lake Baikal, the proportion of PAHs with four, five and six benzene rings (fluoranthene > pyrene > benz(b)fluoranthene) increased; they are of pyrogenic origin and are formed at high temperature processes of organic fuel combustion (while combusting coal, wood, liquid fuel). We revealed a positive correlation between the content of aerosol particles and PAHs. The revealed concentrations of aerosol particles (1,0-13,7 mg/m³) and benz(а)pyrene (0,01-0,22 ng/m³) rated in Russia did not exceed the MAC. Despite the prohibition of production and limited use of PCBs, their traces were found in various industrial and background regions worldwide. It is shown that polychlorinated biphenyls content in Lake Baikal near-water atmosphere (0,48-5,63 pg/m³) is comparable to the concentrations observed in background regions worldwide (0,04-25 pg/m³).

Methodological approaches to the identification of hydrologically sensitive landscapes have been developed and implemented in the Selenga River basin. The topographic humidity index TWI was calculated to detect accumulative landscapes using the digital relief model of the region under study. Areas with TWI ranges of 12-15 and 15-18 were recognized as areas with the most likely runoff zones. To assess the possibility of their influence on the formation of the river runoff composition, a map of the total runoff was created using the Flow Accumulation model. Hydrologically sensitive watershed areas (HSA) were determined by superimposing a spatial distribution map of areas with maximum total runoff values on the TWI differentiation map. Areas with the contours located within the territories of maximum values of total runoff were identified as true hydrologically sensitive landscapes. Model polygons were selected to test the methodology for mapping hydrologically sensitive areas and primary pollution sources. Studies were carried out on the model territory of the city of Ulan-Ude, which is one of the main pollutants of the waters of the Selenga River and Lake Baikal. The main condition for the formation of secondary sources of pollution (accumulative landscapes) is the correspondence of the pollution source coverage area with HSA. The resulting map of production facilities was superimposed on the HSA spatial distribution map, fragments of which within industrial zones were identified as possible secondary sources of pollution (critical sources areas - CSA). The accuracy of the CSA allocation has been confirmed by the results of assessing the level of soil pollution in the city of Ulan-Ude.

One of the main directions of the modern study of landscape structure is timely updating of the structural and dynamic features of geosystems, taking into account the degree of anthropogenic load. The article examines the historical prerequisites for the development of ideas about the physical and geographical division of Orenburg oblast. A geoinformation analysis of remote sensing data has been carried out using neural network algorithms based on self-organizing Kohonen maps in order to compare the structure of natural boundaries with the actual structure of natural-anthropogenic complexes. For this purpose, we calculated quantitative indicators (namely, the area of the physical-geographical region, the number of classes (types of tracts), the number of landscape contours, the average number of contours in a class, the average area of one contour, the density of contours in the physical-geographical region, the coefficient of complexity, the maximum possible complexity of a landscape, the absolute organization of a landscape (a measure of imbalance), the relative organization of a landscape, and the coefficient of landscape fragmentation) and indices of differentiation of the landscape structure (coefficients of entropic complexity and Shannon diversity, and indices of heterogeneity of Ivashutina-Nikolaev, Odum, Glison-Margalef, and Simpson). Moreover, schematic maps of the region’s territory were compiled, reflecting their spatial distribution over landscape areas. Based on the results of the study, tendencies of changes in the landscape structure of Orenburg oblast have been determined. They include changes in the degree of contouring of geosystems, dynamics of the severity of interlandscape boundaries, anthropogenic dispersion of geosystems, the degree of dominance of individual elements of the landscape. Differences in the tendencies of changes in the landscape structure of forest-steppe, petromorphic and hydromorphic geosystems in comparison with the arid steppe landscapes prevailing in the region have been identified depending on the degree of agrogenic and technogenic transformation.

Fluvial processes play an important role in the transformation of the relief in the Fore-Baikal region. The structure of valley geosystems is one of the important indicators of the dynamic state of fluvial systems. Nevertheless, insufficient attention is paid to the its study in the Fore-Baikal region. The large-scale mapping of the valley geosystems of the Kitoy River in different geodynamic settings was carried out based on the data of complex field works and orthophotography made using UAVs. The features of their spatial structure and dynamics were analyzed. As a result of the study, it has been found that the geomorphologic structure of the territory, which determines the rate of channel deformations and the intensity of slope processes, has a significant impact on the development of valley geosystems and their spatial structure. The section of the Kitoy River valley, which is formed in the flat part of the basin, is characterized by the most complex structure. In the mountainous part of the river basin, there is a fragmented development of individual morphological elements of the valley and lower diversity of elementary geosystems. Based on the results of the analysis of successional changes in the soil-vegetation cover on different morphological elements of the valley, the main stages in the development of the valley geosystems were determined, and the quantitative characteristics of the main indicators of the development stages of floodplain generations and their dynamic state were obtained. For geosystems of the low and middle floodplain of the Kitoy River valley, fluvial processes are the leading factor in the formation of their spatial structure and dynamics, with the exception of the high mountain part of the basin, where they are smoothed out by cryogenesis processes. The series of successional changes in the soil-vegetation cover on these morphological elements are identical almost throughout the entire length of the valley. Geosystems of high floodplains and low terraces, formed under conditions of weakened influence of fluvial processes, have more pronounced features of mountain and piedmont taiga, depending on the change in altitudinal belts.

The article considers ecological and geographical features of officinal plants distribution within the highlands of Northeastern Transbaikalia. The concept of ecosystem diversity was used as a methodological basis of the study. According to it, the orobiome presents a key regional unit for inventory and assessment of mountain biodiversity. Comparative geographic and cartographic methods of analysis of original field data, papers and maps were applied. We have identified 40 species of pharmacopoeial plants for the Northeastern Transbaikalia orobiome. The taxonomic, biomorphological, ecological, geographic, and altitudinal characteristics have been considered, and the analysis of composition of active substances and the use in the treatment of diseases according to the international classification of diseases ICD-10 has been carried out. It has been revealed that the highest number of species are applied when treating diseases of the digestive system, diseases of the circulatory system, and diseases of the respiratory system. Five geographical groups of pharmacopoeial species have been identified, among which species with the Holarctic distributional type prevail. Boreal species predominate among nine ecological-coenotic groups. The coenotic value of pharmacopeial species in vegetation communities of the orobiome is considered. Some species of officinal plants are coenose-formers, predominant in the background communities for the belts; they include Scots pine, Siberian fir, lingonberry, marsh rosemary, downy birch, and bearberry. The regional and altitudinal features of pharmacopeial species distribution have been revealed. The highest number of species grow on the North Baikal highlands, while the smallest number - on the Patom highlands. There occur more than 20 species in the mountain-taiga belt, and about 5-10 species in the high-mountain belt. A map of communities with the participation of typical species of pharmacopeial plants of resource importance has been compiled. It has been revealed that the greatest diversity of these resources is concentrated on the North Baikal highlands due to climatic conditions and geographical location at the junction of biogeographical boundaries. The compiled map can be used to assess the ecosystem potential of the vegetation cover of a poorly explored region. The expediency of further study of the pharmacological properties of local flora species used in traditional medicine, as well as strengthening of measures for the protection of medical plant species, were noted.

The article discusses the results of the complex landscape survey of the Nabil plain, Northern Sakhalin, Russia. The 20 km long landscape profile allocates three major geographical complexes. The main pattern of the landscape structure is related to the age and genesis of the area. The current landscape structure of the Nabil plain includes 31 land units. Within the landscapes, the peculiar features of the soil and vegetation cover are observed, and the main factors of landscape differentiation are the redistribution of runoff associated with the topography and lithological conditions. The spatiotemporal sequence of the land units at the recent marine terraces is related to the coastal sediment accumulation and redeposition. Seven land units are identified here. As a result of mechanical disturbance and deflationary processes in the initial weakly stable complexes of coastal terraces, disturbed land units occupy up to 30 % of the total landscape area. For the coastal plain, 10 land units are identified; up to 90 % of the total landscape area is covered by swamps. Pyrogenic modifications occupy up to 70 % of the total landscape area. The highest landscape diversity is characteristic of the piedmont plain (14 units of the first order). The high conservation value of the dark coniferous forests dominating the landscape is shown. Modified and weakly stable land units (cleared areas and disturbed swamps) occupy up to 1 % of the landscape area. The landscape structure and diversity are represented on a large-scale map; its fragments reflect the main patterns of the landscape distribution and contain information on topography, soils and vegetation. The large-scale map can be used for the environmental monitoring goals, taking into account increasing levels of the man-caused impact at the natural complexes of the northern Sakhalin.

The purpose of the study is to identify the spatial relationship between the population and production of the territories of the south of Yenisei Siberia (Krasnoyarsk Territory without northern areas, the Republic of Tyva and the Republic of Khakassia). The study was conducted using statistical, cartographic and comparative geographic methods; urban districts and municipal areas were chosen as units of statistical observation. The main results include identifying the main urbanized areas and transport corridors in places of maximum population concentration. Thus, the demographic potential of the Krasnoyarsk part of the Trans-Siberian transport corridor makes up more than half of the region’s population, while it receives migrants from peripheral territories. The branches of industrial specialization have been singled out, and a grouping of municipalities of the region has been carried out according to the volume of industrial production (4 groups have been identified). The influence of the level of development and distribution of productive forces on the demographic situation and the transformation of settlement systems has been assessed. The correlation between the population size and the volume of industrial production for the set of urban districts is very high (0,98), and for the set of municipal districts is very weak (0,28), indicating large differences. Сonsideration of cities as nodes of the supporting framework of the region’s territory shows a very strong correlation between population and industrial development, which is obscured when the analysis is extended to the entire territory of municipal districts. The geographical aspects of spatial development are expressed in the strengthening of the central-peripheral gradients of the concentration of population and production. Modern market conditions through the strengthening of economic contrasts, the weakness of subsidized budgets, and the degradation of local infrastructure affect the demographic situation. In all the regions considered, the dominance of capital cities in terms of demographic and industrial potential has been noted; it is these administrative centers that are regional points of growth. The grouping of municipalities by production volume shows the unevenness of industrial development. The leaders and nodes of the supporting framework of the territory are cities with developed industries of great all-Russian, regional or export significance as well as centers with extractive industries.

This article discusses the features of the tribal composition, population and settlement of the Evenks of the Barguzin Baikal region in the period from the 17 ^th to the 20 ^th centuries. The study was conducted using the methods of cultural geography, statistical data of the population, archival documents and other historical sources. The paper also applies the concept of ethno-cultural landscape, which allows studying the relationship between community, cultural tradition and place. The study is focused on the tribal composition, number and distribution of the Evenks, taking into account ethno-contact zones and socio-cultural standards. The main sources of data are the works of researchers, archival materials and field studies of the authors. The analysis made it possible to characterize the processes of formation of the number and identification of the Evenks of the Barguzin Baikal region. The natural landscape has an impact on the economy and settlement of the ethnic group. The areal stability of settlement and confinement to the necessary natural resources for life support have been revealed. It is shown that the tribal composition of the Evenks exhibits relative stability, but at the same time it is subjected to the influence of migratory mobility and intercultural contacts. The main areas of the historical settlement of the Evenks are associated with hunting, fishing and cattle-breeding complexes. The largest number of Evenks and the number of settlements with a share of the Evenk population were recorded in the pre-revolutionary period. During the Soviet period, there were changes in settlement and a radical geocultural restructuring of the Evenks’ way of life. From that time to the present, the transformation of the traditional way of life and identity of the Barguzin Evenks has continued. On the basis of the historical-geographical approach, the data on the settlement of the Evenk ethnic group, confined to the cattle-breeding and hunting-trading areas, are summarized. The materials of field observations confirm the continuity of historical memory, cultural traditions of local groups, their features and significance in the habitation of space. Features of the tribal composition and localization of the genera of the Barguzin Evenks of the the 17 ^th - early 19 ^th century influenced the formation of the modern settlement of the Evenk and mixed population of the Barguzin Baikal region.

The article presents, for the first time, the results of determining visitor loads on the natural territories of the Pribaikalsky National Park obtained during the warm seasons of 2018-2021. The study used the method of “Limits of Acceptable Changes” recommended for the World Natural Heritage Site “Lake Baikal”, adapted by the authors of the article for the natural territories surrounding the lake. The obtained numerical values of recreational capacity for the main objects open to the public in the Pribaikalsky National Park should be considered as corresponding to the maximum permissible loads, the excess of which leads to changes in natural conditions and the loss of tourist attractiveness of the object. The study shows that for the Pribaikalsky National Park, which includes more than a quarter of the Baikal coastline, a one-time presence of 5285 people is permissible on 93 sites and trails allowed for visiting, located within ten forestry departments. Examples of determining current capacity estimates are given for three objects, namely: Babushka Bay, Sagan-Zaba Tract and Saraisky Bay. An attempt has been made to compare the data of the maximum loads with the general statistics of the issued visiting permits for the period 2018-2022. About half of them are connected with the Olkhon Island, which accounts for about a third of the total maximum loads, which became possible after the construction of decking trails, isolated canopies, dry closets and platforms for cars in 2018-2021, which made it possible to increase recreational capacity without increasing the load. The practice of admitting visitors to the natural territories of the Pribaikalsky National Park is currently based on estimates obtained using the method of limits of acceptable changes and algorithms for determining the current capacity, which are annually adjusted by environmental monitoring data. Regular construction of new and updating of existing infrastructure are also taken into account, allowing for an increase in the number of visitors simultaneously within the boundaries of the park.

Modern scientific research in the field of geoecology, urban ecology and urban planning focuses on the issues of geoecological assessment and management of sustainable development of urban systems (urban geosystems). In the article highlights both traditional methods of geoecological assessment, including environmental risk assessment, comparison of MPC and MPL indicators, as well as modern methods such as remote sensing of the Earth (analysis of satellite images) and modeling - multifractal analysis of urban geosystems. In addition, the article uses data from state statistics and environmental monitoring of the city and data from its own field research. It has been established that in order to solve the problems of urban planning and management of territories based on the principles of sustainable development, such a system of geoecological assessment is required that would reflect the degree of development of the structure of urban geosystems, including the deviation of the development of urban geosystems from the optimum in conditions of multicomponent anthropogenic loads and risks of disruption of the sustainable functioning of the urban geosystem. Using the fractal modeling of the impact of anthropogenic factors, data on the deficit or redundancy of their impact were calculated. The advantage of territorial planning and the proposal of measures for the sustainable development of the city of Vidnoye based on fractal analysis consists in justifying of the optimal degree of construction and development of the transport network, in reducing the risk of chaotic sprawl of the city and problems (first of all, congestion of roads and pollution of environmental components), and also in achieving a minimum level of spatial fragmentation of the urban environment.

The analysis of data on the chemical composition of wetland waters, groundwaters and river waters in the catchment area of the Poyang lake, obtained in the course of Russian-Chinese hydrogeochemical studies during 2013-2022, was performed. The bulk of the laboratory work was carried out at the Tomsk Polytechnic University using the mass spectrometric method with inductively coupled plasma. It is shown that wetlands that are not used economically are a source of organic substances and their transformation products entering the groundwater of the upper hydrodynamic zone. An anthropogenic impact on surface and groundwaters has also been established, which manifests itself in a rather sharp increase in the concentrations of certain chemical elements and their compounds. But at the same time, a significant ability of the region’s water bodies to self-purify was revealed. Thus, in the low-water periods of 2019 and 2022 a decrease in the contents of As, Cd, Ni, Sb, V, Mo, and W in the waters of the Jinjiang river was noted, which is 17-120 times and more already 100-200 m downstream from wastewater outlets. Based on the analysis of measurement results, thermodynamic calculations, mathematical modeling of hydrogeochemical processes and published materials of other authors, it was concluded that the most likely explanation for this ability is a combination of the following factors: precipitation of poorly soluble substances (calcium and magnesium humates and carbonates, and clay minerals) with the total content of dissolved salts amounting to more than 300-400 mg/dm³; coprecipitation of a number of microelements, which increases with a decrease in the effective diameter of sediment particles (0,003 mm or less); and the involvement of substances removed from the solution in biogeochemical processes, the intensity of which increases under favorable climatic conditions (such as in the catchment area of the Poyang lake).