Home – Home – Jornals – Siberian Journal of Forest Science 2024 number 3

The methods of Infrared (IR) and Raman spectroscopy, as well as gas chromatography, were used to assess the distribution, content and composition of water-containing defects in variously deformed milky-white vein quartz of the Larino deposit. Weakly deformed quartz and quartz with intensive polygonization and recrystallization, in which water is present in molecular form, in fractures, channels, intergranular space, as well as in the composition of fluid inclusions, are analyzed. The content of water-containing defects, according to IR spectroscopy and gas chromatography, decreases in a series from weakly deformed primary granular coarse-grained quartz to blocked and recrystallized. The obtained results indicate the release of water during recrystallization, along the newly formed grain boundaries by diffusion and further homogenization to achieve an equilibrium state. Gas content also depends on the degree of deformation changes in samples and decreases from large coarse-grained differences to intensely deformed quartz with a high content of recrystallized grains.

In this work, based on structural and phase analysis data, we consider the behavior of Au nanoparticles (NP) during the formation of interphase boundaries between quartz and copper and iron selenides upon annealing at 450 °C and different selenium activities: lg f _Se2 = -2.4 with a melted selenium buffer and lg f _Se2 = -3.15 according to the indications of the indicator mineral mixture γ-Fe_{1- x} Se and δ-Fe_{1- x} Se. In two series of experiments, contrasting textural features (nano- and microstates) of the initial metal phases were used, which made it possible to construct 2D and 3D models of interphase boundaries. In the first case, thin layers of gold NPs (~30 nm thick), iron (~50 nm thick), and copper (~50 nm thick) were deposited onto quartz crystals less than 40 μm in size by magnetron sputtering, i.e., all metals were in a nanosized state. In the second case, iron, copper, and selenium (in eskebornite stoichiometry - CuFeSe₂) were introduced into the system in the form of micron-sized powder materials (1-10 microns). Gold still remained in the form of NPs on the quartz surface. The thermal annealing products were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, and X-ray photoelectron spectroscopy (XPS). The study showed that, regardless of the activity of selenium, annealing of Au NPs leads to partial enlargement of particles (up to submicron sizes) based on the self-assembly mechanism (the size distribution of Au particles corresponds to a lognormal law with a maximum shifted towards smaller sizes), and gold remains in the metallic state. The 2D model of the interphase boundary is a mineral mixture of copper selenides (Cu₂Se), iron (γ-Fe_{1- x} Se) and islands of submicron gold particles formed on the surface of quartz. The 3D model of the interphase boundary is characterized by the fact that Au particles are concentrated mainly in eskebornite, and not on the quartz surface. Moreover, NPs are localized in the pores of mesoporous eskebornite, and submicron particles with a size of ~ 200 nm or more are displaced to the surface of eskebornite particles. Based on the data obtained, typomorphic features of the presence of Au NPs in the ore-forming processes of the formation and development of gold ore deposits are formulated.

Data from the Chuktukon, Tomtor (Russia), and Morro dos Seis Lagos (Brazil) mineral deposits demonstrate that the mineral potential of laterite produced by weathering of carbonatites can be extended with Fe, Mn, Ti, and V, which are commonly beyond the conventional ore production. Several previously unknown factors have been revealed, which control the mineral potential of laterite: reduction of weathering products, composition and ore contents of carbonatite, lateral and vertical migration of elements, as well as liquid fractionation of colloids in upper zones of weathering profiles. The reported study provides additional arguments for the idea that laterite derived from carbonatites stores unique multicomponent mineralization of heavy lanthanides, Y, Sc, Fe, Mn, Ti, V, Sr, Ba, Al, and Ga, besides the common target commodities of Nb, La, Ce, and P.

The search for oil and gas in folded zones and in the foredeep of the cis-Uralian region for many decades was reduced to drilling quite easily identified anticlinal structures and reefs located at shallow depths. Many important discoveries were made as a result, but the overall effectiveness of the work remained relatively low. On the one hand, this was due to the insufficient information content of the data for reliable preparation of structures in regions of complex structure. On the other hand, the peculiarities of the development of oil and gas systems in these regions were ignored during the assessment of prospecting sites. In comparison with traditional producing centers in the platform regions of the Volga-Ural and Timan-Pechora basins, this distinguishing feature was caused by a thicker sedimentary cover, the variability of its composition and structure, and multiple phases of structural development. Many failures were due to the formation of traps after the passage of the primary migration flow of oil and gas, low capacity of reservoirs, and their breaching by faults. As shown by interpretation of new geodata using modern knowledge about the oil and gas potential of regions of similar structure, the cis-Uralian region contains poorly studied oil and gas accumulation zones that can contain large deposits. These include blind thrust regions, subsalt traps in zones of dislocated diapirs, and also stratigraphic and combined traps associated with unconformities and facies changes. The utmost attention is paid to new prospecting objects in the Timan-Pechora basin in which the thickness of the Paleozoic cover has increased. The delineation of new promising objects in these zones has become possible due to new knowledge and better geophysical data.

Integrated seismic, drilling, and other exploration works in the southeastern Anabar-Khatanga petroleum province since the early 1930s led to discoveries of small oil and gas occurrences and one large filed of Central Olgino. However, the petroleum potential of the northwestern part of the province remains poorly investigated and evaluated. The reservoir potential appraisal is attempted in this study using all available seismic, geological, and geochemical data, including evidence from four new wells drilled in the Sopochnoe uplift and the Zhuravliny swell. The obtained data provide constraints on the extent of oil and gas generation, accumulation, and losses from degraded traps in Permian strata that have the highest potential as source rocks. The source rocks of the Upper Kozhevnikovo, Lower Kozhevnikovo, and Tustakh formations have been characterized in terms of thickness, contents of organic carbon and chloroform bitumen, maturity (catagenesis) of organic matter, and density of oil migration and gas generation. The maximum possible estimates of oil and gas resources that can potentially accumulate in structural traps, without migration losses, are obtained for each of the three reservoir formations by basin modeling. Judging by geological and geochemical criteria, the Upper Kozhevnikovo Formation can preserve only a minor portion of initially accumulated hydrocarbons, while the oil and gas accumulations, as well as the petroleum generation potential of organic matter in the Lower Kozhevnikovo and Tustakh formations, were destroyed by late Permian-Early Triassic trap magmatism and Mesozoic-Cenozoic tectonic activity.

The paper presents data on different types of Late Jurassic carbonaceous-siliceous-shale sequences of marine deposits in the western side of the Frolovskoye basin. The diverse sedimentation patterns in the area were presumably controlled by tectonics, sea bottom topography, and currents, with voluminous gas venting through large faults. Recent exploration drilling in the Elizarovo trough and the Vygnlor basin revealed Upper Jurassic sections of a previously unknown type with low-radioactivity lower strata markedly thicker at the account of biogenic radiolarite intercalations affected by postdepositional carbonatization. The lithology of these rocks is described with implications for deposition environments and extent of such sections.

Upper Devonian carbonate reef complexes have been studied on the territory of the Kolyvan-Tom’ Folded Area in sections in the right bank of Tom’ River. Facies analysis of the exposed part of the reef complex indicates the predominance of fore-reef and continental margin depositional environments of a tectonically active margin. The identified conodont associations are represented by cosmopolitan representatives of the genera Ancyrodella , Ancyrolepis , Icriodus , Mehlina , Palmatolepis , Polygnathus and “ Polylophodonta ” suggesting a correlation with the punctata - jamieae , rhenana - linguiformis , triangularis and Lower crepida conodont zones. The largest conodont diversity occurs at the triangularis / crepida boundary. Biofacies analysis of ostracod distribution has led to identification of characteristic associations and their restriction to certain parts of the palaeobasin. Substage boundaries yielded ostracods with both smooth and ornamented shells. In the lower part of the substages, smooth forms predominate, whereas the middle and upper parts of the substages are characterised by forms with tuberculate and reticulated surface. Hollinella valentinae Beds were traced in the Upper Frasnian Solomino Formation, and Acratia granuliformis Beds were traced in the Lower Famennian Kosoy Utyos and lower Mitikha members. Isotope geochemistry of the Upper Devonian sections of the south of Western Siberia reveals Frasnian global events - the Middlesex/ Punctata and the Upper Kellwasser, their stratigraphic position confirmed by palaeontological data, as well by as the globally expressed negative carbon isotope anomaly. These boundaries are marked by changes in depositional regime reflecting sea-level eustatic fluctuations, which are complemented with faunal changes.

To study the geological structure in the search for raw hydrocarbons within the Volga delta and the Caspian Sea, two intersecting profiles of magnetotelluric sounding were performed. The analysis of geoelectric sections based on the one-dimensional inversion of the initial and normalized invariant curves of apparent resistance showed that it is necessary to use methods of three-dimensional mathematical modeling to form reliable geoelectric models. Their initial construction necessary for the three-dimensional interpretation of invariant apparent resistance curves was carried out taking into account their one-dimensional inversion. The resulting model, including the lower structural part, is constructed by the method of interactive matching to the apparent resistance curves of model curves calculated according to the program of three-dimensional mathematical modeling. This approach made it possible to take into account the influence of local galvanic distortions on the apparent resistance curves when evaluating the distribution of electrical conductivity in the lower parts of the subsea deposits. As a result of the integrated interpretation of magnetotelluric data, blocks with increased conductivity have been identified in the subsea deposits of the Northern Caspian Sea, which are most likely associated with high fluid saturation of Cretaceous and Neogene sediments. Their position correlates with the regional discontinuous structures of the region.

Accurate assessment of mineral content and the brittleness index ( BI ) is crucial for designing effective hydraulic fracturing treatments in coal seams, a parameter required in the East Bokaro Coalfield in India. This study combines sidewall-core and well log data, focusing on well A-1, where X-ray diffraction analysis of sidewall cores was conducted to identify mineral content. The obtained mineralogical data were extrapolated to well A-2 through a synthesis of well log parameters, X-ray diffraction analysis, and prior research results. Linear regression equations incorporating known minerals and well log data as input parameters were employed to calculate volumetric mineral content in the formations. The reliability of the model was validated by assessing the minimal difference between predicted and observed log curves. Furthermore, the brittleness index was determined using both geomechanical methods based on compressional wave velocity and mineralogical methods incorporating quartz, feldspar, and dolomite content. Comparative analysis of BI values demonstrated a consistent trend, while variations in the mineralogic BI were observed in relation to mineral content. This study not only establishes a continuous multimineral model for cases with unavailable core data but also contributes to advancing the understanding of mineral content variations. Additionally, the correlation between BI variations and mineral contents enhances our knowledge of the geomechanical properties essential for design of hydraulic fracturing in coal formations. The results presented herein offer valuable insights for optimizing hydraulic fracturing strategies in the East Bokaro Coalfield and provide a foundation for further research in similar geologic settings.

Experimental studies of the composition of atmospheric air are the basis for subsequent numerical analysis of pollution processes and management decisions to improve the quality of the urban environment. The processes of long-term air pollution in Irkutsk and the influence of calm conditions on them are studied. An analysis of linear correlations between the measurements of monthly average concentrations of benzo(a)pyrene at stationary posts for monitoring the composition of atmospheric air in the city is performed. It is shown that the results of intra-annual pairwise measurements at posts, in general, are proportionally correlated to each other. The relationships between benzo(a)pyrene concentrations and calm conditions were studied. A correlation between its high concentrations in winter and the frequency of calm weather conditions is revealed. The established patterns create opportunities for external monitoring of observation results at stationary monitoring posts in the city. The derived dependencies allow you to numerically fill gaps in observational data. The results can be used when planning measures to improve the quality of atmospheric air and constructing models for assessing concentration fields.

There is considerable uncertainty about the methane emission from the Arctic shelf seas. Methane fluxes in this region can be underestimated and play a significant role due to the large volume of gas contained in bottom sediments in the permafrost and gas hydrates. We have analyzed the model sensitivity to the parametrization of gas exchange processes on the sea surface. The study is based on the numerical modeling results of the transport of dissolved methane in the seas of the Arctic. The dissolved methane transport model is included in the basic model of the ocean and sea ice developed at the Institute of Computational Mathematics and Mathematics, Siberian Branch, Russian Academy of Sciences. Estimates of methane emissions into the atmosphere were made with various parametrization of the gas exchange process in the "water - atmosphere" and "water - ice - atmosphere" systems using NCEP/NCAR reanalysis data. The uncertainty of the estimate of annual methane emission amounted to 6-12% when considering different dependencies of gas exchange on wind. The scheme accounting the ice cover has a more pronounced influence on the flux: the uncertainty increased to 50-130%. Parameterization of the relationship between ice cover and gas exchange can have a great influence on the calculated methane fluxes and lead to underestimation of its emission from the seas of the Arctic shelf.

The main source of summer heating of the upper layer of the Siberian Arctic shelf seas is shortwave solar radiation. The radiation flux attenuates as it passes through the water column, and the attenuation rate is determined by the optical properties of water, depending mainly on the concentration of suspended matter in the water. In numerical models of the ocean and sea ice, the process of absorbation of shortwave solar radiation is described by various parameterizations. In the present work, the sensitivity of the regional 3D numerical ocean and sea ice model SibCIOM to two parameterizations of the penetrating radiation is studied: (1) two-component parameterization using constant attenuation coefficients for the infrared and visible parts of the spectrum depending on one of the 10 transparency classes of ocean waters; (2) a three-component one, with different absorption coefficients for the red, green, and blue parts of the visible spectrum and relying on satellite data on chlorophyll concentration. Analysis of the results of numerical experiments for the water area of the Siberian shelf seas has shown that taking into account the seasonal distribution of chlorophyll concentration when forming the flux of penetrating shortwave radiation leads to the formation of regions of water warming in the surface or bottom layer, which differ from the basic experiment with two-component parameterization.

Atmospheric monitoring from global satellite navigation systems is usually used to estimate the integral water vapor of the atmosphere. In addition, such parameters as the zenith tropospheric delay of satellite radio signals and its gradient parameters characterizing atmospheric mesoscale irregularities measured with high temporal resolution. The work shows a significant variability of these atmospheric characteristics associated with sever convective weather phenomena. A sample of several hundred events of severe weather phenomena corresponding to available observations of the nearest satellite stations in the Republic of Tatarstan and Moscow region located at latitudes 55-56° N is used. It was found that under the conditions of severe weather phenomena, the inhomogeneity of the zenith tropospheric delay field of satellite signals strongly increases which manifested in the increase in its gradient parameters and their fluctuations, as well as in the growth of the integral water vapor. The intensity of fluctuations of integral water vapor most strongly changes if the station is located not further than 20 km from a hazardous phenomenon, which is explained by the size of convective cells. However, even at the station location at distances of up to 200 km from hazardous phenomena, an increase in the atmospheric integral water vapor and the effect of amplification of inhomogeneity as compared to mean multiyear data are observed.

In the presented work, the process of heat and mass transfer inside an original design nozzle for a catalytic reformer of diesel fuel in a low-mass-flux mode is investigated by direct numerical simulation using Open FOAM open-source code. The main goal of a new nozzle design is to increase the rate and degree of fuel evaporation, as well as to improve the mixing characteristics of diesel fuel with superheated water vapor before the reaction mixture passes through the catalyst. Inside the nozzle, there are two regions where flows with opposite swirl directions are created; this leads to a strong velocity shear inside the nozzle, intensifying the mixing processes. Simulations were carried out in the Eulerian-Lagrangian formulation, taking into account the processes of evaporation of fuel droplets. The simulation results show that the flow at the outlet of the nozzle has a good uniformity of the mixture composition and provides a high degree of fuel evaporation at the early stages of flow development.

The present study is aimed at searching for mechanisms of wave interaction in a supersonic boundary layer on a flat plate with the flow being distorted by a streamwise disturbance generated on a sharp leading edge by a pair of weak shock waves. The space and time distributions and the frequency-wave spectra of oscillations and their wave characteristics in the linear and weakly nonlinear phases of wave train development in a nonhomogeneous boundary layer under conditions of a fixed power of the local source of controlled disturbances are analyzed. Based on experimental results, possible variants of wave interaction in a supersonic boundary layer on a flat plate in the region of the longitudinal wake generated by an N-wave are proposed.

Numerical simulation of the final viscous stage of degeneration of a momentumless turbulent wake behind a sphere in an isotropic turbulent flow is performed using a modified e ~ ε turbulence model. The laws of degeneration are consistent with those for a momentumless turbulent wake at absent turbulent background.

The effect of icing on the kinematic and power parameters of the working element of a wind generator blade was experimentally studied using a modified laser Doppler anemometry method. Arctic conditions were modeled in a specially designed aerodynamic climatic setup based on an optically transparent plexiglass tube with a square cross-section of 200×200 mm with the following parameters: flow velocity of up to 20 m/s, temperature of up to - 20°C, and relative humidity of up to 90%. The flow was saturated with moisture by fine aerosol generators. Aerosol generator flows were optimized using laser Doppler anemometry. The following parameters were measured: flow velocities at distances of up to 400 mm behind the trailing edge of the blade and power characteristics of the blade element subjected to icing. The effect of icing on aerodynamic and power characteristics is shown.

A method and results of calculating a laminar-turbulent flow past a swept wing under a control action generated by a source of blowing or suction from the model surface are presented. Pioneering results on the influence of three-dimensional blowing and suction sources on stability of the boundary layer on a swept wing and distributions of N-factors of various mechanisms of the laminar-turbulent transition aimed at changing its position are obtained by using the LOTRAN 3 software package.

Numerical computation of aiding mixed convection and heat transfer characteristics in a channel with a baffled heated wall is carried out in this work. The equations of mass, momentum and energy, alongside the boundary conditions, are solved by the finite volume formulation using the open source OpenFOAM^® code. Simulations are accomplished under different parameter combinations, including the Reynolds number, Grashof number, and baffle dimension. The results are presented in terms of streamlines, isotherm contours, Nusselt number, and friction factor. The results obtained revealed that the flow translates from steady to unsteady state at a relatively low value of Reynolds number. The unsteady flow behaviour contributes to improve heat transfer by disturbing the near-wall region. The augmentation of velocity and baffle dimension leads to a notable heat transfer enhancement; however, this enhancement is less sensitive to the heating intensity augmentation.

The influence of a thin layer of phase change material (PCM) on the thermal characteristics of the outer wall of a building made of lightweight thermal insulation material was studied numerically. Changes in temperature and heat flux density were analyzed for various locations of a PCM layer in the wall. It is shown that the use of a thin paraffin layer 4 mm thick in a wall made of foamed polyurethane 100 mm thick can reduce the amplitude of heat flux fluctuations on the inner surface of the wall in the summer from 2 to 13 times, depending on the PCM location. The greatest reduction is achieved when installing the PCM in the central area of the wall. Calculations show that when using a PCM in the walls of buildings made of light thermal insulation materials, a positive effect, associated with a 6-8 hour delay in the maximum heat flux entering the room relative to the maximum daily value of the outside air temperature, is observed in the summer.

The paper describes the results of an experimental study of the influence of control surfaces and fuselage on the structure of a separated flow around a model of a small-size unmanned flying vehicle with a straight leading edge of the wing. The use of oil-soot visualization and hot-wire anemometry shows that the separation region location depends on the attitude of control surfaces, while the presence of a fuselage leads to reduction of the critical angle of attack.

Supersonic underexpanded air jet modeling based on the QGD algorithm is carried out. The process of jet flow evolution and the formation of unsteady flow regions are investigated to obtain a good qualitative and quantitative agreement of the results with experimental and simulation data, known from the literature. The QGD algorithm is shown to enable studies of the structure of shock-wave cells in the initial region of the flow, and to describe the general character of the turbulent jet.

The paper presents the experimental results on unsteady nucleate boiling on the heater surface with rapidly increasing surface temperature. Analysis of the results of high-speed video recording with a frequency of 180,000 frames per second and a spatial resolution of 5.5 μm per pixel shows that the input data for existing models of heat transfer during nucleate boiling must be refined to take into account the existence of cluster and pulsating bubbles. It has been established that bubbles, interacting through the exchange of momentum, heat and steam mass, accelerate the activation of neighboring vaporization sites, so the clusters of bubbles can form at the initial stage of covering the heater surface with steam. The main characteristics of isolated, cluster and pulsating bubbles have been studied for the wall overheating from 0 to 14 K above the temperature of nucleation onset and flow underheating from 23 to 103 K.

This paper presents the study of permeability of helium through walls of hollow glass silica microspheres, which can be used as membranes for gas flow. The study was performed in a special setup for measuring the kinetic sorption curves for helium at given pressure and temperature. A mathematical model based on a mono-dispersion distribution was used for approximating the experimental data. The data was obtained for the temperature range 21.5 -110.0 °С. The helium permeability of microsphere walls and the activation energy for helium sorption by microspheres were defined for this temperature range.

Constructing models of thermophysical characteristics of polymer composite materials in the curing process is a highly pressing task that is substantiated in this paper. A mathematical model of hot curing of polymer composites based on a thermosetting resin in a mold is presented. Based on experimental temperature dependences of thermophysical characteristics measured under different conditions, modeling dependences of the volume heat capacity and thermal conductivity of fiber, fabric and granular polymer composites on the degree of cure and resin fraction during curing are obtained, with their distinctive feature being the replacement of the properties of a porous reinforcing filler with those of the cured resin in the model. The results of experiments and calculations are presented. The proposed models of thermophysical characteristics increase the accuracy of process modeling and calculation of optimal temperature-time curing cycles.

The study is aimed at clarifying and revealing the basic principles of the effect of superheated steam and its parameters on the content of solid carbon particles (soot) in intermediate and final combustion products when burning liquid hydrocarbon fuel. Using a laboratory atmospheric atomizing burner, it was determined that there is a significant amount of solid carbon particles at the base of the burner flame. When heated air is used instead of steam, an increase in soot content by ~ 75% is observed. The analysis of the flame glow intensity in a narrow ultraviolet band also showed that in air the glow values are ~75% higher than when using superheated steam. At the same time, it has been established that the soot content in the final combustion products is affected only by the parameter of the dynamic impact of a jet, which determines air ejection from the environment both into the gas generation chamber and into the external flame region.

The paper presents the results of experimental studies on the effect of multi-walled carbon nanotubes (MWCNTs) additives on the viscosity and rheological characteristics of drilling emulsions based on mineral oil. The formulations of typical drilling fluids containing 65 % hydrocarbon phase were modified with nanotubes. The mass concentration of nanotubes in emulsion varied from 0.1 to 0.5 %. The formulation and method of preparing stable drilling emulsions with MWCNT additives have been proposed. The rheology of drilling emulsions modified with MWCNTs was studied. The dependency of rheological characteristics on the nanotubes concentration was obtained. In general, MWCNT additives can significantly alter the rheological characteristics of drilling hydrocarbon emulsions at lower concentrations compared to the additives in the form of spherical nanoparticles. This is very important for their practical use in industry. The optimal concentration of MWCNTs for controlling the rheological properties of drilling emulsions is about 0.25 wt. %.

Considering some limitations of various macroscopic chemical reaction models including the total collision energy (TCE) and general collision energy (GCE) models, the new modification is implemented in the DSMC algorithm for numerical simulation of dissociation of the air along the stagnation line and around a typical hypersonic atmospheric blunt body, STS-2 in non-equilibrium conditions and modified model is compared with others conventional models. Since the TCE and GCE models are dependent on some experimental parameters ( A and B at Arrhenius rate of reaction equation). Also, due to lack of accuracy of the quantum kinetics model, modification version of chemical reaction models is presented as hybrid of modified quantum kinetics (MQK) and modified collision energy (MCE) which this method is able to extract A and B parameters without need experimental background. Accuracy of the current applied chemical model for calculation of flow field characteristics is assessed by comparison of their results with other methods (analytical models and available experimental data). The results indicate that the modification of hybrid model with advantages of independency of the empirical parameters gives more accurate results and provides more accurate solution compared to conventional methods without need A and B constant experimental parameters.

The analysis was performed for input-condition sensitivity of haemodynamics simulation for the zone of abdominal aortic aneurysm. We took three versions of patient-specific configurations of aneurism and computed the haemodynamics with different spatial and velocity profiles at the inlet. Their impact on haemodynamic characteristics was evaluated. At total, the study was performed for three spatial variants (uniform, parabolic and parabolic-and-secondary-flow velocity profiles) and three versions of time behavior of velocity profiles: this produces nine cases for every of three chosen geometries. The study demonstrated that we can neglect the impact of spatial profile for inlet velocity (including the non-coaxial velocity vector components). Meanwhile, the value of reverse diastolic flow is significant for the solution. However, simulation in the zone of abdominal aortic aneurysm does not demonstrate great differences in simulation results for the values of wall shear stress and velocity for the data averaged over a cardiac cycle. For the distribution of the oscillation index of shear, the maximum deviation from the basic solution is about ~ 10 %, which is quite acceptable for clinical applications.

The capsule review of the scientific editor for the thematic issue of the Siberian Journal of Forest Science, 2024, number 3 is presented, dedicated to stationary forest studies.

Although there are no official and permanent criteria for determining the position of your name in the list of authors of an article, the principle of “authors at the both sides of the list” is increasingly used in biomedical publications. The best addition to it is a detailed indication of the contribution of each author to the creation of the article.

In the indigenous southern taiga fern-forb fir forests on the Tom-Yaya interfluve (Tomsk Oblast), the characteristics of tree stands, underbrush, undergrowth, coarse woody debris, ground cover, soils and their contribution to carbon sequestration were studied. The average stock of the forest stand for the type of biogeocenosis was 315.8 ± 56.1 m³/ha, the average stock of the Siberian fir ( Abies sibirica Ledeb.) in different stands varied from 99.2 to 201.4 m³/ha. In terms of forest health condition, the forest stands are weakened to varying degrees, the fir elements of the forest stands are stronger, which is largely due to their damage by the invasive four-eyed fir bark beetle ( Polygraphus proximus Blandford). The underbrush is sparse or of medium density (880-2720 pieces/ha), formed mainly by red raspberry ( Rubus idaeus L.) and rowan ( Sorbus sibirica Hedl.). Undergrowth with an absolute predominance of fir, its number (800-920 trees/ha) characterizes unsatisfactory regeneration in all studied stands. The average volume of deadfall for the type of biogeocenosis was 2.1 ± 0.5 m³/ha, stumps 3.3 ± 0.8 m³/ha, brushwood - 9.2 ± 5.3 m³/ha. The features of the phytocenosis include high values of floristic diversity (131 species), species richness of the grass cover (105 species) and species richness of plant communities (57 species per 400 m²). The increased participation of ferns in the composition of the grass stand is due to the presence of windows occupying from 5 to 30 % of the area of the phytocenosis, formed in stands at the site of fallouts and dead trees, mainly due to the drying out of fir damaged by the four-eyed fir bark beetle.. For the first time, data have been obtained on the phytomass of the ground cover of southern taiga fir forests in Western Siberia, estimated on average at 0.88 t/ha, with a wide variation of this indicator due to the peculiarities of the horizontal structure of the ground cover and different illumination in sub-canopy parcels and windows. The features of the composition, structure and thermal regime of the soils of the studied biogeocenoses are shown. Data are presented on changes in the productivity of phytocenoses, soil humus and carbon reserves in various components of the studied forests.

The Tellerman experimental forestry of the Institute of Forest Science, Russian Academy of Sciences, located in the southeast of Voronezh Oblast, has a long history. It was established on the initiative of Academician V. N. Sukachev in 1944 as a place to conduct complex long-term studies in broad-leaved forests on the border between forest-steppe and steppe. For almost 80 years specialists of different profiles worked in the territory of the forest area: foresters, geobotanists, soil scientists, zoologists, microbiologists, entomologists, phytopathologists. Extensive studies was carried out on the hydrology of the massif and water regime of stands, the environment-forming role of the forest, phytomass reserves were determined, productivity of stands in different forest types was determined, and a cycle of silvicultural experiments was established. The comprehensive study of biogeocenoses also included root systems, phenological, geobotanical, zoological, entomological, microbiological and mycological studies. The scientific basis for the establishment of pedunculate oak ( Quercus robur L.) crops in the forest-steppe was developed, taking into account its form diversity and the results of silvicultural experiments laid down in the first decades of the forest region’s existence. The study of silvicultural aspects of oak stands degradation allowed us to develop practical methods of reproduction of oak forests on clear cuts of stands mixed with oak by sowing acorns with a shortened period of thinning.

The structure of the upper part of permafrost and the topographic features in the northeast of Western Siberia were shaped by changes in the natural environment in the Late Pleistocene and Holocene. In 2016-2021, sections of different landforms - ridges and thermokarst-erosional hollows - were studied within the third lacustrine-alluvial plain of the Pur-Taz interfluve. The upper part of the plain includes the Kargin-Sartan alluvial, lacustrine, and slope sediments and Holocene peatlands. Based on the stratigraphy and new geochronological data on the Pur-Taz interfluve, the consequences of the activation of neotectonic processes in the Sartan period and the influence of climatic factors on the differentiation of accumulative and denudation processes in the Holocene were identified.

This study is aimed at a preliminary analysis of ground temperature data from ten thermometric boreholes drilled and equipped by the authors in the Upper Kolyma Highland (Magadan region) in 2021-2022. The boreholes of up to 15 m in depth are located in characteristic landscapes (rocky talus, mountainous tundra, larch woodland, river valleys) of the highland at heights from 618 to 1182 m asl. Continuous monitoring of ground temperatures with a time step of 4 h was carried out. Data on the mean annual rock temperatures, seasonal thawing/freezing depths, and the depths of zero annual amplitude were obtained. The mean annual ground temperature varied from -0.1 to -3.8 °C. The depth of seasonal thawing ranged from 0.9 to 2.6 m. The depth of zero annual amplitudes was 11.5 and 13 m in two boreholes. Two boreholes located in talik zones recorded freezing depths of 2.6 and 3.6 m. Ground temperature regimes within the same region differed significantly depending on landscape conditions: elevation, landform, composition of the rock, character of vegetation, and other factors. Based on the data obtained, it is planned to further develop the geocryological monitoring network in the Magadan region. For some of the boreholes, a full annual cycle of observations on ground and air temperatures, precipitation, and snow cover depth is available. As information on the state of permafrost in the territory under consideration is virtually absent, publication of the obtained data of relatively short-term observations is relevant and timely.

A new model of pure water freezing potential (Workman-Reynolds potential) explained the positive electric charge of ice relative to water during crystallization by the fact that protons were captured faster than hydroxide ions by numerous traps of charge in ice - interstitials. In the present article, additions have been made to this model to extend its application from pure water to aqueous solutions with an impurity concentration in the parent solution of 10^-4 mol/L or more. The additions take into account the ability of impurity anions and cations to act as acceptors for protons and hydroxide ions in ice. As a result of capture by acceptors, the equilibrium concentrations of protons and hydroxide ions can shift significantly in favor of the former or the latter. This shift should radically affect the kinetics of filling the charge traps (interstitials) with protons or hydroxide ions and the sign of the electric charge of ice relative to the solution. In particular, the model explains the negative ice charge during crystallization of 10^-4 mol/L KCl solutions.

Based on observation data on typical areas of the Prioksko-Terrasny Reserve for 1999-2021, the influence of snow accumulation on the dynamics of the groundwater level was clarified with due account for the variability in air temperature and precipitation. An assessment of the spatial heterogeneity of seasonal and long-term variability in meteorological characteristics and the groundwater level was made. A regression analysis demonstrated that the snow storage has a significant influence on the long-term dynamics of the groundwater level during both the snowy season (December-April) and the maximum rise of the groundwater level (May-July). The effects of the air temperature of the cold season, duration of thaws, and the accumulated positive air temperatures during them on the groundwater level were statistically insignificant. The obtained conclusions complement the results of studies of the relationship between the variability of snow cover characteristics and the depth of groundwater under the conditions of modern meteorological regime and can be used to specify regional features of water exchange processes.

Experimental and numerical modeling of the temperature regime and the deformed state of the highway structure, which is a geotechnical system of “subgrade and the foundation of the highway made of frozen soil”, was carried out. Potential disturbances of the temperature regime are considered, and a design and technological solution for thermal stabilization of the soil foundation under the subgrade in flooded areas is proposed. It implies the use of geocontainers. To study and evaluate the temperature regime of the highway structure, a series of laboratory experiments were carried out. To take into account the viscoelastic properties of the soil in the mathematical model of the soil foundation, time functions of the relative settling of the soil foundation with geocontainers in the chosen temperature regime were obtained.

The proposed calculation takes into account the peculiarities of the operation of the heat pump as part of the surface foundation on permafrost soils, i.e., the heat flow from the heating circuit of the pump to the cooling circuit. Heat transfer reduces the conversion coefficient of low-potential heat into high-potential heat, but, unfortunately, this is ignored in well-known publications. In addition, the calculation shows a significant effect of the freon brand in the evaporation-condensation circuit of the refrigeration machine on the conversion coefficient.

Igor Emelyanovich Guryanov, Candidate of Technical Sciences, passed away on February 3, 2024, after a long battle with a serious illness. A renowned expert in the field of foundation engineering and frozen soil mechanics, he worked at the Melnikov Permafrost Institute for many years. He developed a new field in geocryology - engineering cryolithology - and authored two fundamental monographs on this very promising topic. He was a member of the International Society for Soil Mechanics and Geotechnical Engineering.