Home – Home – Jornals – Siberian Journal of Forest Science 2024 number 2

Based on the mathematical apparatus of stochastic gradient adaptation, an algorithm for estimating the parameters of image registration according to the criterion of the maximum Shannon mutual information is synthesized. Expressions for the gradient of mutual information are derived. At the same time, the derivatives of the entropy of the images according to the estimated parameters are found using the Parzen window method. Optimization of the synthesized algorithm is carried out, aimed at improving its performance.

A method for visualizing complex objects representing a composition of volumes and functionally defined surfaces using graphics processors is proposed. The method uses hierarchical 3D data structures that do not require parameterization. Combinations of complex translucent volumes and surfaces based on perturbation functions are described.

Currently, ongoing tasks involve research in the field of spray cooling, droplet interaction with complex surfaces, and droplet evaporation from solid walls. Automated digital image processing methods are utilized to conduct these experiments, particularly when recording large amounts of video data. This paper presents methods for recognizing objects in digital images to obtain quantitative characteristics of evaporating droplets in low-light conditions. New algorithms have been developed to identify and close object boundaries under conditions of limited visibility, enabling measurement of the geometric parameters of evaporating droplets. A comparison is made with data obtained using the manual image processing method, and the conditions for the applicability of the proposed algorithms are demonstrated.

Specific features of calculating the group delay time of a signal based on digital measurements of the S-parameters of microwave devices are discussed. Methods for calculating the group delay time of a signal with a random noise component based on differentiation by the increment method and approximation are discussed. A method for calculating the group delay time based on the differentiation method using a sliding piecewise-linear approximation is proposed. This algorithm is more resistant to the noise component of the signal in question than the standard method for calculating the group delay time of a signal based on the one-way difference method and has a smaller computational complexity than the method considered in the article based on quadratic approximation. The results of testing the operation of the described methods are presented, which illustrate their suitability for use in calculating the group delay time.

In this work, the surface morphology of InAlAs layers deviating from the lattice-matched composition with an InP substrate is studied. A linear relationship is shown between the dimensions of the pits and the thickness of the grown layer. The possibility of forming an array of nanopits uniform in size and shape on the surface of an InAlAs layer is demonstrated.

Vertical nanowire shape modification during the annealing process due to the readsorption of the material evaporated from neighboring wires and from the substrate are numerically calculated. The evaporation model from a set of isotropic point sources and the Knudsen-Lambert model are applied. The effects of the aspect ratio of the nanowire length to the distance between them and the material evaporation rate from the nanowire sidewall and the substrate on the nanowire shape are analyzed.

The methods of passivation of photodetector mesastructures based on InSb/In_1-xAl_xSb nBn heterostructures grown by molecular beam epitaxy have been investigated. The mesastructures are formed by photolithography and liquid etching methods. For passivation of the mesastructure surface, two different dielectrics Al₂O₃ and Si₃N₄ are used. It is shown that the Si₃N₄ dielectric completely passivates the surface of mesastructures and the bulk current is prevailing, while the surface leakage current dominates in mesastructures passivated by Al₂O₃. At small reverse biases, the correlation between the current value and the contact area is violated due to the influence of defects. Modelling of the mesastructure current-voltage characteristics at 77 K shows that the main contribution to the dark current is made by the tunneling current of electrons through the In_1-xAl_xSb barrier.

The effect of operation of a frequency converter based on an electro-optical Mach-Zehnder type modulator on the frequency spectrum of the output signal in the down-conversion mode has been studied. It is shown that the modulator does not introduce significant changes in the distribution of the power spectral density of the converted signal, including phase noise, compared to the signal at the input of the modulator.

Materials with non-standard physical properties are widely used in various fields of science and technology, from microelectronics to heavy industrial installations. International scientific teams carried out mathematical calculations showing that the most promising compounds of B-C structures, which have strong chemical sp²- and sp³-bonds under certain external conditions and concentration ratios. Such materials are characterized by high hardness, resistance to aggressive media, and electrical conductivity. This study is aimed at synthesizing and investigating carbon-containing BC_x films. The paper presents the results of measuring a thin BC₅ film. The spectral characteristics of the film, data on the layer thickness, conductivity, and composition of the film are obtained using X-ray, Raman, and photoelectron spectroscopy.

The influence of the number of elements of the ring antenna array on the quality of focusing the wave inside the ring and the ability to control the focus location is investigated. Controlled focusing is supposed to be used to scan the internal structure of the patient with a controlled focus for tomography or delivery of ultrasonic energy to a given area of the patient's body. The research is carried out by mathematical modeling. The simulation results show that thinning of the number of elements on the annular antenna array leads to the formation of interference rings in the area of focus image reconstruction. At the same time, the size of the focal spot remains unchanged.

Magnetometric measurements are widely used to solve problems in geology, navigation, and a number of other areas. Currently, there is a tendency to miniaturize and reduce the cost of magnetometers. However, the readings of inexpensive magnetometers are distorted by errors, which requires a calibration procedure. The article describes mathematical error models that are used in most well-known scientific research and adopted in this work. Mathematical modeling of the measuring signals of the magnetometer is carried out, and the principle of calibration of the magnetometric sensor, based on the accurate measurement of changes in its spatial position in a constant magnetic field, is proposed and researched. Estimates are given of the accuracy of restoration of calibrated parameters and the signal restoration errors achievable when performing the calibration operations proposed in the study.

The paper studies the possibility of using a long short-term memory (LSTM) neural network to simulate the operation of a PID controller. A PID regulator has been implemented to control a heater with a temperature sensor by using the Arduino framework. An LSTM model trained on the controller data has been developed. It is shown that the neural network model quite accurately reproduces the regulator operation and can completely replace it. In addition, the applicability of this model as a detector of abnormal operation of the PID controller is shown.

The problem of traffic control is solved using a model-oriented method. To develop a mathematical model, an automaton formalism is proposed. In strict accordance with the problem conditions, the states of a deterministic finite automaton (DFA) and predicates of directed transitions are defined. To implement the DFA, a transition is made to the Harel diagram (statechart), which is a unified mathematical and software support for modern global modeling tools. The solution to the problem posed is proved constructively by a table of states with the corresponding dynamics and computational experiments of the selected scenario in advanced domestic and foreign instrumental environments for modeling the designated class of event systems. Computational experiments show complete agreement with constructive analysis.

Micropowders made of transparent semiconductor and dielectric materials (ZnSe, MgF₂, CaF₂, SiO₂, BaF₂, MgAl₂O₄, Al₂O₃, Nd:Y₂O₃, YSZ, and TiO₂) are theoretically studied. The refractive indices of these materials are in the range 1.38 ¸ 2.48. As a result of calculations, it is found that the combination of scattering and interference of radiation increases its intensity by one or two orders of magnitude compared to the intensity of the incident radiation in a medium of particles several microns diameter. It is shown that this enhancement increases with the refractive index of the particle material. In our opinion, both nonlinear mechanisms of laser radiation absorption and avalanche ionization lead to an increase in the electron concentration in such local maxima. As a result, the material begins to heat up to the point of ablation.

The paper presents the results of numerical simulation of one of the least studied excimer lasers, a KrCl molecule laser. The simulation was carried out in a 1D approximation, where laser radiation were calculated along the optical axis between plane-parallel mirrors, and the system of kinetic equations and the Boltzmann equation were solved in each transverse layer of the active medium. The theoretical data well agree with the results for the EL series KrCl laser (HCEI SB RAS). The effect of the excitation discharge width on the energy characteristics of the laser is numerically shown. The suggested model and the obtained estimates can be used as tools for optimizing initial parameters when developing more powerful laser systems.

IR lasers are widely used in various fields of science and technology. In this regard, expanding the spectral range and obtaining effective generation in the IR is an urgent task. The object of our study is a laser based on the self-terminating transition of Eu atom with a radiation wavelength of 1.76 mm. In this work, we investigated the possibility of increasing the output parameters of such a laser by increasing the length of the active zone of the gas discharge tube (GDT). It is shown that increasing the volume of the discharge tube from 157 to 314 cm³ while maintaining the pump power level at 1200 W makes it possible to double the output power and laser efficiency. For the first time, an average radiation power of 2.5 W was achieved at the 1.76 mm line. The maximal efficiency of 0.3% is achieved at a pump power of 500 W. After 100 hours of operation, the energy characteristics of the Eu+Ne laser with an active zone volume of 314 cm³ demonstrated good repeatability, which allows us to conclude that it is possible to further increase the energy characteristics and lifetime of this laser. The results of the work can be used in microprocessing of materials, as well as in active optical systems associated with the visualization of fast processes.

The location of the electrodes of a copper vapor laser (CVL) discharge tube in cold buffer zones, where there are no metal vapors, leads to the formation of a phantom current before the “breakdown”. This necessitates the evaluation of whether the phantom current is an additional factor limiting the energy characteristics and what is the mechanism of this limitation? It is shown that at the initial stage of pumping, the intrinsic capacitance of the discharge tube is charged up to the “breakdown”, which determines two processes during this period of time - the population of metastable states of copper and the generation of a phantom current, which occurs as a result of shunting of the intrinsic capacitance of the discharge tube by the cold buffer zone from the anode side of the discharge tube. The mechanism of phantom current generation and its role in limiting the energy characteristics of CVL are considered. The studies indicate two problems on the way to improve the energy characteristics of CVL and the direction of search for their solution: the first is high pre-pulse concentration of electrons in the active medium and the second is the generation of a phantom current caused by processes in the cold buffer zones.

The fields of pollutant dispersion in the air from three operating flare installations at the territory of the Mamontovskoye field in the Nefteyugansk region of the Khanty-Mansi Autonomous District were modelled on the basis of climatic data and technological parameters of flare installations. The amounts of pollutants entering the atmosphere from associated petroleum gas combustion were calculated: carbon monoxide (CO) - 83 %, nitrogen dioxide (NO₂) - 0.7 %, soot -10 %, methane - 6 %. The vegetation cover was mapped relying on the Sentinel-2 satellite image with the shooting date of June 14, 2021, displaying dispersion fields for СО, NO₂ and soot. The distances from emission source (flare installation) to isolines with CO and soot concentrations equal to 1 MPC_st (5 and 0.15 mg/m³) are 163 and 505 m, respectively (here MPC_st is the maximum permissible concentration for short-term exposure level). Similarly, measured distance to the isoline with NO₂ concentration 0.1 MPC_st concentration (0.02 mg/m³) is 284 m. On average, CO concentration decreases by 1 mg/m³ at a distance of 86 m and becomes equal to 0.2 mg/m³ (0.04 MPC_st) at a distance of about 572 m. The resulting model for CO dispersion does not contradict MERRA-2 satellite data, according to which the concentration of CO in the vicinity of the flare installation was 0.2 mg/m³. The gas chromatographic - mass spectrometric analysis of soil samples and plants collected to the north-east from the flare installation at a distance of 216, 486, 710, 1037 and 1380 m has shown that aliphatic hydrocarbons prevail in the composition of soil organic matter. Their content varies from 50 to 80 % of all identified compounds, with the predominance of high-molecular homologues (C₂₇-C₃₃). The maximum total amount of n -alkanes (75.3 μg/g) was detected in the soil sample taken at a distance of 710 m from the flare installation. In the organic matter of pine needles and blueberry leaves, C₂₇ homologue dominates, and C₂₅, C₂₉, C₃₁ characteristic of terrestrial vegetation are present. In addition, polyaromatic compounds were identified in the soil: anthracene/phenanthrene, fluoranthene and pyrene.

Within the framework of green chemistry principles, the concept of deep eutectic solvents (DES) was used to develop solid commercial forms of oil-displacing compositions. It has been shown that the eutectic composition on the phase diagram of the binary system ammonium salt - carbamide corresponds to DES as the basis of solid commercial forms of oil-displacing composition with the best physicochemical and technological characteristics. The optimal concentrations of solid commercial forms in the working solution of the composition were determined for the ternary DES system ammonium salt - carbamide - water. The results of laboratory studies and field tests of the working solution based on the solid commercial forms of the oil-displacing composition are presented.

Postsynthetic treatment of ZSM-5 zeolite with an aqueous solution of NaOH was carried out, followed by the modification of the treated zeolite with nanosized nickel powder. Nickel powder is introduced into the zeolite by dry mechanical mixing. The textural, acidic and catalytic properties of the original ZSM-5 zeolite and zeolite-based samples after alkaline treatment and modification are studied. The catalytic activity of zeolites has been studied in the process of conversion of straight-run gasoline fraction of oil. Along with determining the characteristics of the target reaction products - high-octane gasolines, an analysis of the resulting gaseous hydrocarbons and carbon compaction products (coke) was carried out. It has been established that alkaline treatment of zeolite and its subsequent mixing with nickel nanopowder leads to a decrease in the total specific surface area and total specific pore volume, a decrease in the concentration of acid sites and an increase in their strength. The enhancement of the combined effect of alkaline treatment and modification with nickel nanopowder on the textural and acidic properties of zeolite catalysts was determined. It has been shown that modification of zeolite catalysts has almost no effect on the composition of gaseous products formed in the conversion of straight-run gasoline fraction of oil. Post-synthetic alkaline treatment of ZSM-5 zeolite significantly reduces its aromatising and cracking activity, resulting in an increased yield of high-octane gasoline with improved environmental characteristics. The introduction of nickel nanopowder into alkali-treated zeolite enhances this trend, although not significantly. On modified zeolites, the amount of carbon compaction products is reduced, which will increase the time of stable operation of the resulting catalysts and improve the conditions for their regeneration.

Resins extracted from heavy high-viscous oil of the Nurlat oilfield were investigated. The composition of fragments bound through sulphide and ether bridges in the molecules of initial resins and the liquid products of their conversion at 450 ^oC under the conditions of laboratory experiment was studied using a set of physicochemical methods (IR spectroscopy, UV spectroscopy, gas chromatography -mass spectrometry, chemical destruction). It is shown that the fragments undergoing destruction are mainly those bound in the structure of the initial sample through the least thermally stable functional groups of esters and aliphatic sulphides. Sulphur- and ether-bound compounds in the structure of both resin samples are represented by n -alkanes, n -alkylcyclopentanes, n -alkylcyclohexanes and hopanes. The presence of nickel porphyrins was established among the sulphur-bound compounds. It is the molecular composition of bound n -alkanes that changes most noticeably during thermolysis. Ether bond cleavage in the molecules of secondary resins leads to the formation of products containing mono- and dibromides of alkyl biphenyls. This fact provides evidence that these aromatic compounds are present in resins in the form of fragments bound with other structural fragments through one and two ether bridges.

The extraction of sulphur-containing compounds of diesel fuel (DF) with ionic liquids (IL) based on imidazole with various substituents (butyl, octyl, nonyl, dodecyl, cetyl) in position 1 of the imidazole ring has been studied; the composition of sulphur-containing compounds and polycyclic aromatic hydrocarbons (PAH) has been determined by gas chromatography - mass spectrometry in the initial and purified diesel fuel. The optimal extraction conditions are determined: temperature 30-35 °C, extraction time 60 min, DF/IL ratio 1.66-2. The most effective extractant for the sulphur-containing compounds of DF is 1-nonyl-3-methylimidazolium bromide, which allows reducing the total sulphur content from 0.369 to 0.143 wt%. Results of the studies of group and individual composition of dibenzothiophene (DBT) and PAH derivatives show that the degree of extraction of DBT derivatives and tricyclic aromatic hydrocarbons is 66-72%. Naphthalene and its homologues are extracted to a lesser extent - 37%. Among DBT homologues, dimethyldibenzothiophene is extracted most completely.

The results of rheological measurements of a low-temperature composition based on inorganic components developed at the Institute of Petroleum Chemistry SB RAS (GALKA ^® ) are presented. The studies were carried out with a Haake Viscotester IQ rheometer using CC25 geometry (oscillation mode at a frequency of 1 Hz) at different temperatures. The amplitude test determined the range of strain and stress amplitude values corresponding to the range of linear viscoelasticity. For a given value of the deformation amplitude from the range of linear viscoelasticity, the dependences of the complex viscosity modulus (|η*|), the elastic modulus (storage modulus, G' ), and the viscosity modulus (loss modulus, G'' ) on time were recorded at a temperature of 38, 30, and 20 ºС. The kinetics of the gel formation process was characterized, the maximum strength of the formed structure was estimated from the maximal elastic modulus, the time of its formation and the starting points of gelation were determined.

A composition characterised by adjustable physicochemical parameters within a broad range has been developed relying on the results of studies of the phase equilibria in the ternary system of deep eutectic solvents (DES) glycerol - carbamide - boric acid. The effect of this composition on oil recovery enhancement is studied, and results obtained in the laboratory studies of the effect of DES-based composition on the filtration characteristics of a heterogeneous formation in the carbonate reservoir of the Usinsk field are presented. The efficiency of the composition for oilfields at the early and late stages of development has been assessed by physical modelling. The treatment of a model of a heterogeneous reservoir with the composition is determined to cause a substantial increase in oil displacement coefficient at either low or high temperatures due to equalisation of filtration flows, an increase in reservoir coverage, and restoration of initial permeability. Investigation of the composition and properties of heavy high-viscosity oil before and after treatment with the composition shows that the application of DES-based acid composition does not affect the qualitative composition of oil. The use of the composition leads mainly to redistribution of the content of low- and high-molecular structures: predominantly light occluded hydrocarbons are displaced, while heavy oil components are adsorbed on the reservoir.

Laboratory modelling of oil pollution of water bodies was carried out using the diesel fuel - water - mineral phase system. The content and composition of organic compounds in each of the parts making up the system were studied by gas chromatography - mass spectrometry. The direction of changes in the composition of n -alkanes, polycyclic aromatic and naphthenic hydrocarbons, cyclohexanes, alkylbenzenes and trimethylalkylbenzenes present in diesel fuel during the transition from diesel fuel to the aqueous and mineral phases has been revealed.

The products of oxidative destruction of asphaltenes of heavy Paleozoic oils from the Ashalcha and Nurlat oilfields differing in the age of host sediments have been studied. It is shown that oxidation of the asphaltenes of both oils by hydrogen peroxide in the presence of acetic acid results in the release of occluded compounds. The compounds identified in their composition include n -alkanes, steranes, hopanes and methyl esters of n -alkane acids. A peculiarity of the asphaltenes of Nurlat oil occurring in the Devonian sediments is the presence of n -alkenes in the composition of occluded compounds. The presence of occluded compounds in the structure of asphaltenes is confirmed by the results of X-ray diffraction.

The ecological state of hard-to-reach oil-producing territories of West Siberia has been studied. Results of the analysis of enhanced vegetation index (EVI) dynamics are presented in order to assess the state of vegetation cover over the territories of hydrocarbon fields of in the Yamal-Nenets Autonomous District using moderate resolution imaging spectroradiometer (MODIS) satellite data. The average EVI values of vegetation over oilfield areas were calculated for full growing seasons from May 25 to September 20, 2013-2022. It has been determined that, on average, EVI values for the entire growing season in 2022 became higher by more than 20 % compared to the data in 2013. The trend to an increase in EVI in the final growing season over the 10-year period under study was identified.

The dynamics of the composition of biomolecules in the leaves of Caragana arborescens and Sorbus aucuparia shrubs, typical of the South taiga natural climatic zone, was studied by gas chromatography - mass spectrometry in the process of post-pyrogenic restoration at the territory near the Golovina village, the Tomsk Region, 3 months, 1 year and 2 years after the fire event. Acyclic organic compounds have been identified: n -alkanes, fatty acids, n -alkane-2-ones, aldehydes, n -alkanols. The long-chain saturated alcohol 10-nonacosanol was found in the leaves of Sorbus aucuparia . Aliphatic diterpenoids phytone and the isomers of phytol, triterpene squalene, as well as naphthenoaromatic compounds vitamin E (tocopherol) and vitamin K1 (phytanodione) were detected among isoprenoid structures in the leaves of S. aucuparia , increased phytol and fatty acid levels are observed in the leaves of S. aucuparia 3 months and 1 year after the fire event, and then the concentrations of these compounds decrease to background values after 2 years. Squalene content in the leaves of S. aucuparia , which decreased as a result of the fire event, increased sharply the following year, and after 2 years, it still remained at a level significantly higher than the background. The fire had the greatest impact on the long-chain alcohol 10-nonacosanol, which was detected in large amounts in the leaves of S. aucuparia . As a result of the fire, there is a drop in its content to trace amounts, followed by a slight increase the following year and an abrupt increase up to background values after 2 years. During the two-year-long post-pyrogenic restoration, changes in the molecular mass distribution of acyclic compounds are observed. The leaves of S. aucuparia, sampled 3 months and the following year after the fire, exhibited a shift from higher molecular homologues to less higher molecular n- alkanes and n- aldehydes in comparison with the leaves from background sites, while the corresponding shift observed in C. arborescens related to n- alkane-2-ones. The distribution of acyclic compounds in the post-pyrogenic area approaches the background level 2 years after the fire.

The combined oxidation of gaseous (propane, butane) and liquid (heptane, octane, nonane and decane) alkanes in a barrier discharge plasma in oxygen has been studied. Oxidation process involves simultaneous conversion of gaseous and liquid hydrocarbons. Various C₁-C₄ hydrocarbon gases and mainly oxygenated compounds corresponding to hydroxyl and carbonyl compounds with the same number of carbon atoms in molecules as in the initial alkanes were detected among reaction products. At the stage of chemical reaction initiation in a barrier discharge, the electrons in the discharge interact with all the molecules of the initial mixture to form atomic oxygen and various hydrocarbon radicals. Their subsequent transformation leads to the formation of peroxide radicals of the corresponding alkanes, and their disproportionation leads to the formation of hydroxyl and carbonyl compounds. The mechanism of gaseous alkane oxidation is generally comparable to the mechanism of liquid hydrocarbon oxidation in a barrier discharge, and the key role in the mechanism of alkane co-oxidation is played by the interaction of atomic oxygen with a gaseous or liquid alkane. A probable mechanism for the combined oxidation of gaseous and liquid alkanes in a barrier discharge is proposed on the basis of experimental and literature data, and a simple equation is deduced, linking the rates of atomic oxygen interaction with alkane molecules to hydrocarbon concentrations in the gas phase of the discharge gas in the reactor. Applying the obtained equation, it is possible to estimate the direction of the oxidation of gaseous and liquid alkane mixtures and to involve the experimental data in calculating yet unknown rate constants of atomic oxygen interaction with alkane molecules. The results obtained make it possible to optimise the experimental conditions for the oxidation of gaseous and liquid alkane mixtures with the predominant oxidation of a gaseous alkane. These data will be useful in developing effective methods for the direct processing of a broad fraction of light hydrocarbons.

An approach including preliminary oxidation of vacuum gas oil, chromatographic separation of oxidation products, and thermal treatment is considered. Analysis of the products formed in the cracking of polar and non-polar components of vacuum gas oil oxidised with a mixture of hydrogen peroxide and formic acid is described. It has been established that heat treatment of non-polar components allows obtaining up to 85 wt% distillate fractions boiling up to 360 °C, with sulphur content less than 0.3 wt%. The heat treatment of polar components leads to the formation of distillate fractions at a level of about 50 wt%, and sulphur removal reaches 50 %. It has been shown that the cracking temperature of polar oxidation products determines the route of sulphur removal: at a temperature of 450 °C, sulphur-containing fragments are accumulated in coke, while at 500 °C they are predominantly subjected to destruction with the formation of gas components. It has been determined that gaseous products formed in the heat treatment of both polar and non-polar components of oxidised vacuum gas oil mainly consist of saturated hydrocarbons of the C₁-C₃ series and carbon dioxide. The advantage of separate cracking of polar and non-polar components is elimination of undesired effect on the products formed in thermal decomposition of these components on the route of reactions proceeding in the system. The products obtained in this way are characterized by higher quality. In addition, variation of cracking conditions for separate components of oxidized vacuum gas oil makes it possible to regulate the depth of components destruction and, accordingly, the material balance of the process as a whole.

Zeolites of the structural type ZSM-5 were synthesized using a template, which was pentaerythritol (PER), carbamide (CA), or a deep eutectic solvent (DES) - a binary mixture of PER and CA. It is determined by IR spectroscopy and X-ray diffraction analysis that the nature of the templates used in the synthesis of zeolites affects the phase purity and the degree of crystallinity of the obtained samples. The textural and acidic properties of zeolites and Mo-containing catalysts prepared from them by dry mechanical mixing with nanoscale molybdenum powder have been studied. It is shown that the textural properties of zeolites depend on the template nature. The use of CA promoted obtaining the zeolite with maximal specific surface area and pore volume. The strength of the acid centres of unmodified samples, depending on the structure-forming additive, decreases in the series: DES > CA > PER, and the concentration of acid centers of both types, on the contrary, decreases for zeolites in the series: PER > CA > DES. The catalytic activity of synthesized zeolites has been studied in the processes of non-oxidative methane conversion and refining of the straight-run gasoline fraction of oil. The dependence of the activity and stability of samples on their physicochemical properties caused by the template nature is determined. It has been shown that zeolite synthesized using DES and the 4.0%Mo/ZSM-5 catalyst obtained on its basis exhibit higher activity and stability in the processes of non-oxidative methane conversion into aromatic hydrocarbons and in upgrading the straight-run gasoline fraction of oil, in comparison with zeolite-based catalysts obtained using PER or CA.

The methods for producing cryogels and hydrogels from viscous aqueous solutions of polyvinyl alcohol (PVA) and their rheological properties are considered. Freezing an aqueous solution of polyvinyl alcohol, its exposure to negative temperature and subsequent thawing at a positive temperature lead to the formation of elastic cryogels. Chemical cross-linking of individual PVA molecules into spatial networks is accompanied by the transformation of aqueous solutions into hydrogels. Sodium tetraborate and glyoxal were used to structurise the polymer solutions. It has been determined that the interaction of these reagents with the functional groups of the polymer causes an increase in the viscosity of three-component systems “PVA - glyoxal - water” and “PVA - sodium tetraborate - water” with time. The kinetics of gel formation in the products of chemical reactions was investigated at different concentrations. It is shown that the viscosity of the studied systems increases with an increase in the concentrations of low-molecular reagents in both cases (PVA - glyoxal and PVA - sodium tetraborate). Hydrogels formed at a positive temperature were subjected to additional freezing-thawing cycle, cryogels were obtained, and their rheological properties were studied. The elastic properties of cryogels were determined to be more clearly pronounced than those of hydrogels. Hydrogels can be used as instantaneous gel-forming systems to protect from dangerous chemicals and to make waterproof barriers in hydraulic structures, as the elastic properties are enhanced after cryogenic exposure.

Using information from the database of the Institute of Petroleum Chemistry SB RAS and the methods of statistical and spatial analysis of geographical information systems, we evaluated the data on oil occurrence conditions in the Bazhenov, Domanik and Kuonamka Formations of the oil and gas bearing territories of Russia, the development of which will allow discovering the new sources of increased oil production. The digital maps of the arrangement of hydrocarbon fields in the Bazhenov, Domanik and Kuonamka sediments over the territories of the Volga-Ural, Timan-Pechora and Lena-Tunguska oil and gas bearing basins are presented. The distribution of oils from these deposits over the depth of occurrence in each basin is shown. The lithological features of reservoir rocks are established. The average values of reservoir parameters characterising the filtration and capacitance properties of the pools in these sediments are determined. To analyse the conditions of Bazhenov oil occurrence, a batch of 2833 oil samples from 127 fields of the West Siberian basin was used, for Domanik oil - 407 samples from 195 fields of the Volga-Ural and Timan-Pechora basins, and for Kuonamka oil - 117 samples from 28 fields of the Lena-Tunguska basin. A comparative analysis of the geological and physical characteristics producing a direct impact on the development regime and the effectiveness of technologies used to extract these hard-to-recover oils was carried out: permeability and porosity of rocks, reservoir temperature and pressure. It is shown that the Domanik and Kuonamka sediments are the closest in characteristics to the reservoirs of the developed American shale oil fields, which indicates the possibility for effective application of the positive experience of the United States for Russian oilfields. The results of the study can be used in the development of new and improvement of existing methods and technologies for the extraction and processing of hard-to-recover oils from the studied sediments.

Biogeochemical transformations of sulphur in the saline lakes of southeastern Transbaikalia have been studied. Quantitative measurements show that hydrogen sulphide is present in the water and bottom sediments of most of the lakes studied. In addition to hydrogen sulphide, the presence of sulphate, thiosulphate, and elemental sulphur was detected in the water column, while sulphate and elemental sulphur were found in the bottom sediments. It was established that elemental sulphur exists in the lakes primarily in the form of suspension and colloids, as well as polysulphidic sulphur, the amount of which increases with increasing water pH. It is concluded from the isotopic ratios of sulphur for sulphate, hydrosulphide ions, and elemental sulphur that sulphur in the studied natural systems is controlled by biological and geochemical processes. One of the processes controlling the behaviour of sulphate ions in the lakes is sulphate reduction, which leads to the enrichment of sulphate sulphur and depletion of sulphur in hydrogen sulphide with the ³⁴S isotope. It is shown that oxidation of reduced sulphur in the lakes proceeds with the participation of oxygen, iron, manganese, as well as various bacteria. The presence of an additional source of sulphur and/or absence of sulphur reduction causes ³²S accumulation in sulphate ions. It is determined that the loss of sulphate ions due to their bacterial reduction in bottom sediments is most pronounced in the chloride and soda lakes of the I and III subtypes. In the sulphate and soda lakes of the II subtype, an increase in the amount of sulphate ions was detected.

The discharge of untreated or insufficiently treated sewage into water bodies leads to their pollution, contributing to the emergence and spread of viruses and bacteria that have a negative impact on the ecosystem. One of the indicators of water contamination by pathogenic microorganisms is ammonium ions. The sorption method based on industrial waste as sorbent precursors has become widespread for treating wastewater from ammonium ions. The article presents the results of studies of a calcined sorbent based on ash-and-slag wastes from thermal power engineering plants for the treatment of real wastewater, discharged into the Kuban river within the city of Krasnodar, to remove ammonium ions (NH₄⁺ concentration 21 mg/dm³). The effect of sorption time (10, 30, 60, 90, 150, and 180 min) and sorbent dose (0.5, 1, 2, 3, and 5 g) on treatment efficiency is investigated. The experimental data are processed on the basis of kinetic equations. It is shown that the equation of the pseudo-first-order (Lagergren) provides the best description of experimental data on sorption in comparison with the pseudo-second-order equation (Ho and McKay) and the Elovich equation. It has been established that internal diffusion adsorption is the limiting stage. Treatment efficiency was 72.8 % at a sorbent dose of 5 g for solution volume 50 cm³ and sorption time 180 min. It is shown that the sorbent dose affects the time within which the phase equilibrium between the solution and calcined sorbent is established. The larger is sorbent dose, the larger number of adsorption centres are occupied by ammonium ions per unit time, so, for the fixed ammonium ion concentration in initial solution, shorter sorption time will be necessary to achieve equilibrium. For real wastewater, the time necessary for equilibrium to be achieved exceeds the value determined experimentally with the model mixtures using small sorbent doses. Reasonability of the application of calcined sorbent for treatment of real wastewater is confirmed.

The results of the study of two permafrost-hilly swamp complexes located in the valley of the Chernaya River, the right-bank tributary of the Yenisei River (near the city of Igarka), are presented. Among them are coarse-tuberous and flat-tuberous peatlands of different ages, genesis and stages of development. The modern vegetation cover of the complexes is characterized, a detailed morphostructural description of peat profiles is given, a botanical analysis is performed and the values of the degree of decomposition, ash content and moisture content of peat are determined. The thickness of the coarse-tuberous peat bog deposit is 4.0 m, the approximate age is 8 thousand years ago. In the process of its formation, it underwent six stages of change, of which the first was forest. The peat deposit is classified as forest-swamp and marsh subtypes. The main peat-forming agents from bottom to top of the profile were successively eutrophic hypnosis mosses, mosses ( Hypnales W. R. Buck et Vitt), sedges ( Carex L.), horsetails ( Equisetum L.) and, finally, oligotrophic sphagnum mosses ( Sphagnopsida Ochyra). The flat-tuberous peat bog with a capacity of 1.3 m and an age of about 3 thousand years in its development has gone through two stages of vegetation changes, of which the first is forest. Peat deposit of forest-marsh and marsh subtypes. Throughout its depth, ice layers are recorded. In the lower part of the peat profile, the main peat-forming agents were eutrophic hypnomic mosses, and in the upper part - oligotrophic sphagnum mosses. Changes in the vegetation cover of hilly peatlands occurred both as a result of changes in the regional climate in the Holocene, and due to the appearance of permanent permafrost in peatlands, heaving of mounds and their subsequent thawing. The appearance of spots of exposed peat on the day surface of peatlands and the formation of a powerful lichen cover in their place indicate the cessation of the peat formation process.

We studied poorly drained sedge-sphagnum pine forests ( Pinus sylvetris L.) in the southern taiga subzone of Western Siberia, drained by a network of open shallow channels 25 years ago at the time of the study (geographical coordinates 56°23′71″ N, 84°34′04″ E). The depth of standing swamp waters for three years of research averaged 23.2 ± 9.9 cm during the warm period. Soils - cultivated transitional (mesotrophic) type on powerful sedge-sphagnum peats. They are characterized by an acidic environment reaction - pH 4.0, a loose composition density of 0.10 g/cm³ and an ash content of 8.9-5.2%, decreasing with depth. The soil profile in the warm period is poorly differentiated into a zone of intense oxidative processes (0-10 cm) - 570-660 mV (median 610) and moderately oxidative (10-30 cm) - 430-640 mV (median 590). The main direction (trend) of seasonal fluctuations of the redox potential (RP) is characterized by an average weekly acceleration of 7.2 mV with an average weekly deceleration of 0.23 mV from June to October. RP by the type of linear function is significantly associated: positively with the groundwater level ( R ² = 0.65) and soil temperature ( R ² = 0.56), negatively with volumetric humidity ( R ² = 0.60). A significant second-order parabola-type relationship of RP was revealed: negative - with Fe²⁺ ( R ² = 0.48) and ammonium ( R ² = 0.57), positive with Fe³⁺ ( R ² = 0.39), multidirectional - with Fe_C ( R ² = 0.55) and water-soluble organic carbon ( R ² = 0.54). By the method of canonical analysis, it was found that the RP is determined by a set of hydrothermal indicators by 81 %. The volume humidity contributes the greatest weight to the conditioned effect. Various forms of iron cumulatively estimate the development of RP-reactions by 52 %, the dominant contribution belongs to Fe²⁺. The set of carbon and NH⁴⁺ determines the redox potential by 61 % with the largest weight of carbon in the set of characteristics.

It is accepted that the amount of damage is equal to the difference in the value of the stands before and after the external impact. Hence, the task of determining damage comes down to identifying the cost of the stands. It is shown that the cost can be represented as the sum of the ecosystem (ecological and resource) functions of the stands. The calculation is performed relative to a specific function, the cost of which is known. As such a function, a wood resource was used, which, in the form of a tax rate of payment, is balanced by location, tree species, marketability classes and is widely used as a standard indicator in setting fees for forest use. The sequence of damage calculations is demonstrated using the example of the southern taiga forests of the Yenisei, Nizhne-Yenisei, and North Yenisei forest districts of Krasnoyarsk Krai. There was an outbreak of Siberian silkworm ( Dendrolimus sibiricus Tschetverikov) here between 2016 and 2018. The area with varying degrees of damage to stands amounted to 803,983 hectares. The total area of forest inventory units where tree stand death was recorded is 2,034,665 hectares. To calculate the damage, mass forest survey materials were used as initial data. Descriptions of forest inventory units were analyzed separately for protective, operational and reserve forests. Calculations were made based on the predominant tree species. The cost of protective forests turned out to be more than operational ones, and the cost of ecosystem functions of the stands turned out to be an order of magnitude higher than the tax value of the wood resource. The total cost of stands before the Siberian silkworm outbreak was determined to be 70,275.2 million rubles, after the outbreak - 52,249.8 million rubles. The total damage to forests amounted to 18,025.5 million rubles - 25.7 % of the cost of stands before the Siberian silkworm outbreak.

The article analyzes the viability and silvicultural and reclamation efficiency of stands of silver birch ( Betula pendula Roth), black poplar ( Populus nigra L.) and laurel poplar ( Populus laurifolia Ledeb.) at the age of 33 years, growing in forest belts of checkerboard and row planting methods. Using modern research methods, temporary trial plots were established. It has been established that on chestnut, poorly developed and sandy loam soil with deep groundwater, stands of the noted tree species are at the stage of degression. The best viability (1.8 points) with planting safety of 57.5 % is typical for birch stands created by the checkerboard planting method. The worst viability (4.5 points) and low (14.7 %) preservation are distinguished by stands of black poplar, created by the same checkerboard planting method. The surveyed forest stands are characterized by a weakened and severely weakened vital state. The total lifespan of silver birch in the Koibal steppe can reach 45 years, and black and laurel poplars - no more than 35 years. The protective and silvicultural and reclamation properties of birch forest belts are not sufficiently expressed, they have a satisfactory (3a points) silvicultural and reclamation assessment, they require partial reconstruction and the resumption of agrotechnical care at the edges of the forest belts. Poplar forest belts have completely lost their protective and silvicultural-reclamation functions, correspond to a low (1 point) silvicultural-reclamation assessment, and need to be uprooted and replaced.

Due to climate change, many species of coniferous trees, which are the main forest formers of the forests of Western and Eastern Siberia, have shifts in both latitudinal and altitudinal boundaries of the range. This study is devoted to determining the features of photosynthetic activity and pigment composition of Siberian pine needles growing in the area of the Ergaki ridge of the Western Sayan, during the period of recovery from the state of winter dormancy. Young Siberian pine trees ( Pinus sibirica Du Tour) growing at different heights above sea level were taken as objects of research. In the area of Lake Oyskoe on the territory of the Ergaki Nature Park in the spring of 2023, a transect with four test areas was laid, crossing the timberline during the transition from the mountain taiga to the rocky-tundra area. Single specimens of Siberian pine , spread above the timberline, have a number of ecophysiological features that allow them to survive in fairly harsh conditions. Such features include a greater depth of winter dormancy, when trees in the phase of forced dormancy react more slowly to temperature increases, compared with trees growing below the timberline. For them, apparently, winter-spring thaws will not pose a danger. Strong insolation at low temperatures, characteristic of open mountain slopes in late winter and spring, is also not critically dangerous for the advancement of Siberian pine above the timberline, due to the predominance of carotenoids in the pigment complex of their needles during this period.