Home – Home – Jornals – Thermophysics and Aeromechanics 2023 number 5

This special issue is dedicated to discussing the possibility of the stage division of the Vendian system, specifically, a composite section of the Siberian platform is proposed as a stratigraphic standard. For the Ordovician system of the Siberian platform and Northeastern Russia, certain changes in stratigraphic charts are proposed, nomenclative issues and different variants of correlations of regional horizons with the GSS of Russia are considered. A geochemical analysis of Bajocian and Bathonian belemnite rostra of Arctic Siberia was carried out and for the first time a comprehensive C, O and Sr isotope characterization of the sections was obtained, making it possible to propose a comparison of the studied sections with the European standard and to develop paleogeographic models. Comprehensive studies of the Upper Jurassic and Lower Cretaceous series of the Anabar Bay deposits (Laptev Sea) led to an improved biostratigraphic division for this reference section and to the identification of the levels for interregional and global correlation. The magnetostratigraphic division of the Jurassic-Cretaceous boundary interval and its comparison with the Tethyan regions are discussed. Taking into account biostratigraphic data, the δ¹³C_org variation curve can also serve as a correlation tool. The clinoform structure of Upper Jurassic strata was revealed in the northwest of the Anabar-Khatanga depression, based on the interpretation of seismic profiles calibrated against studied sections. The formation of this complex allows us to consider this stage as the initiation of the Verkhoyan orogeny in this folded area. Analysis of variations in the thickness of sediments allows us to deduce that intense tectonic-sedimentary processes took place during the Late Jurassic epoch, along with subsidence of the bed of the sedimentary basin. Analysis of a specific assemblage of lacustrine fossils from the reference section of the upper part of the Lower Cretaceous series of Transbaikalia and of published data showed that this fossil assemblage was widespread in East Asia. Biofacies analysis made it possible to reconstruct the paleoenvironments of this time.

The way towards the stage subdivision of the Vendian starts with the assemblage of a complete composite geological section of this interval of the Earth’s history, a succession of geological bodies each reflecting a certain ecosystem state. A Vendian composite section of the Siberian Platform, which is a succession of regional to sub-global scale geological bodies reflecting particular states or unidirectional transformations determined by episodic expansion of relatively oxygen-rich environments onto the shelf and alternating with large-scale oceanic anoxia and euxinia events is proposed as a reference for constructing the stage subdivision of the Vendian. The redox instability had to be accompanied by changes in nutrient availability and could not but affect the course of macroevolution and macroecology. The geological record of the Vendian of the Siberian Platform is also marked by episodic increase in alkalinity of the World Ocean. At least five such alkalinity events could be provisionally identified in the composite section of the Vendian of the Siberian Platform. A hypothesis is proposed suggesting that the alkalinity events could control the appearance and disappearance in the geological record of a distinctive suite of sedimentary structures in carbonates, the discrete nature of early diagenetic cementation of aluminosilicoclastic sediments, and fossilization of soft-bodied organisms in the Vendian.

The chronozonal structure of the Mangazeya Superhorizon of Eastern Siberia, which includes the Listvyazhny and Baksan horizons and their chronozones, is considered. Their volumes and stratotypes are given and their place in the regional and global stratigraphic structure is shown, where Mangazeya occupies the middle parts of the Kuzmovsky regional complex and the Caradocian stage of the Upper Ordovician. Proper names for the Lower Dolbor Horizon (Amutkansky) and the Upper Dolbor Horizon (Cherlechinsky) are introduced for the first time.

In the Middle Ordovician sections of the Eriekhe River basin, which are of crucial importance to correlate the regional stratigraphic units of Northeast Russia and the General Stratigraphic Scale (by graptolites), we identified a diverse ostracod assemblage. The new data substantially supplement the Middle Ordovician paleontology of this region. The analysis of the stratigraphic distribution of these assemblages made it possible to verify the correlation of the Eriekhe Structural Facies Zone (SFZ) suites with regional stratigraphic units of the Northeast Russia and, based on homotypic ostracod assemblages, with the horizons of the Siberian Platform. The joint findings of ostracods and graptolites in the studied section allowed us to correlate the horizons of the Northeast Russia and the Siberian platform with the stages of the General Stratigraphic Scale.

The Middle Jurassic sedimentary strata of Siberia remain poorly studied chemostratigraphically. We contribute to the knowledge with pioneering C, O, and Sr isotopic data for carbonate material of belemnites from the Yuryung-Tumus Peninsula and the lower reaches of the Lena River, as a basis for comprehensive description of the north Siberian Bajocian and lower Bathonian. The obtained chemostratigraphic constraints, with new ⁸⁷Sr/⁸⁶Sr ratios and previous δ¹³C and δ¹⁸O estimates, also include data for the lower Bathonian in the Sokur section (Central Russia). Despite the limited amount of material, chemostratigraphy, along with the available biostratigraphic data, allows reliable correlation of the Boreal sections with the primary standard of Northwest Europe, which is impossible for these strata with any of the two methods alone. The δ¹³C, δ¹⁸О, and ⁸⁷Sr/⁸⁶Sr patterns correlate with the records of eustatic, climatic, tectonic, and paleogeographic events. The new δ¹⁸O data and the inferred paleotemperatures for the latest early Bajocian and the Bajocian/Bathonian boundary reveal two excursions of notable seawater warming near the Siberian Arctic coast, which were synchronous with episodes of global sealevel rise. It was presumably during the eustatic events that the N-S Komi Strait (first naming) opened twice in the territory of the Russian Plate. The strait connected the Boreal and Tethyan seas and thus changed the oceanic circulation patterns. Specifically, it opened a gateway for a warm current from the south to northern Siberia responsible for the high seawater temperatures recorded in the δ¹⁸О patterns of belemnites.

The goal of this study was to improve the high-resolution biostratigraphy of the Upper Jurassic and Lower Cretaceous in the type section on the Nordvik Peninsula, Anabar Bay, Laptev Sea. The results were used to identify a succession of 13 foraminiferal biostratigraphic units, 9 dinocyst units, and 8 palynofloral biostratigraphic units in the rank of zones and local zones. Based on new data, the stratigraphic continuity of this section is proved for the Lower and Middle Volgian, where a major stratigraphic hiatus was previously assumed. The established zones have variable correlation potential. Different versions of the subdivision of the section based on ammonites are discussed and the proposed scale is justified. A reference level based on calcispheres/calcareous dinocysts is defined providing global correlations and calibration of beds near Jurassic-Cretaceous boundary in the Tethyan and Arctic regions. The magnetostratigraphic subdivision of the studied section and its comparison with the Tethyan regions are discussed. Together with biostratigraphic data, the proposed δ¹³C_org curve in the Upper Jurassic and lower part of the Valanginian can be a tool for detailed correlations in different regions of the Northern Hemisphere. The cyclicity of carbon isotope composition in the Upper Volgian and Boreal Berriasian and isotope events in the Volgian and Lower Valanginian are determined within the Arctic region. The distribution of geochemical parameters (C_org, δ¹³C_org and hydrogen index) is determined in studied section, geochemical stratification of the section and variations in major oxide compositions are demonstrated. A sharp change in geochemical parameters is identified at the base of the Paksa Formation (Upper Volgian). The distribution interval of the “subsurface chlorophyll maximum” is determined. The study shows that high concentrations of isotopically light organic carbon in the first diasterene geochemical subhorizon were caused by high phytoplankton productivity and were deposited under reducing conditions favorable for preservation of organic matter. The analysis of major oxide compositions of the studied rocks revealed that variations in the chemical composition of the studied rocks reflect changes in their mineralogy and petrography.

New materials on the stratigraphy and structural features of the Bathonian-Neocomian sections of the Anabar-Lena basin are presented. In the territory adjacent to the Taimyr mountain-folded system, a clinoform-like structure of the Upper Jurassic strata has been revealed, which are characterized by high thickness compared to adjacent sections in the east of this region. The lectostratotype of the Chernokhrebetnaya Formation (uppermost Lower Oxfordian-lowermost Volgian) is proposed. The most complete and continuous stratigraphic section is compiled, its litho- and chronostratigraphic correlations are given comparing to the sections of adjacent territories characterized in detail by fossil assamblages. The evidences for a new lithostratigraphic division of the territory are provided, facies zoning of sediments is clarified, a thickness chart of the Upper Bathonian-Boreal Berriasian strata of the Khatanga-Olenek interfluve is proposed.

The age of the Turga Formation in the Middendorf’s outcrop is determined as latest Barremian-earliest Aptian based on fauna and microfossil assemblages. The composition of the fauna and palynomorph assemblages allows correlations between the Turga Formation and the Yixian Formation and lower part of the Jiufotang Formation of Northeast China. Results of the petrographic and geochemical analysis as well as microfossil studies showed that sediments accumulated in a shallow lake with low-energy hydrodynamics, sometimes under low-oxygen conditions. Climate features (warm temperate climate transitional to subtropical) and type of vegetation (coniferous forests with admixture of hardwoods) are reconstructed taking into consideration the composition of spore-pollen assemblages.

A method of reconstruction based on one image of curved surfaces is proposed. To reconstruct the surface, the object's silhouette data and a multi-level elevation map are used. Unlike the known approaches to reconstruction of a single angle, the proposed method does not have a depth limit and requires fewer calculations by an order of magnitude. High-resolution 3D models can be generated interactively.

The creation of a system for controlling the longitudinal motion of aircraft based on the principle of the total energy control is considered. The structure of the control system is presented. It includes a core independently of aircraft calculating commands for deflecting the elevator and thrust obtained on the basis of the principle of inverse models. The control system is implemented for models of three aircraft with different aerodynamic configurations. The study of the quality of regulation is carried out using the numerical modeling method.

The development of methods for controlling the flow and heat transfer in submerged turbulent jets (impact jets) impinging on an obstacle is an important task, because such a configuration is used in various technical applications. The active flow control technology and optimization of the signal that controls the external flow disturbance in impact jets can be applied to exploit the inherent properties of the flow to further enhance heat transfer at the wall. IR thermography is used and measurements are carried out using the PIV (Particle Image Velocimetry) method for optical diagnostics of the wall temperature fields and velocity fields under conditions of flow disturbance control, including feedback from a local velocity sensor. It is found that low-amplitude sinusoidal disturbances increase the integral temperature at the wall due to the intensification of flow separation at the wall compared to an undisturbed jet. It is also established that high-amplitude disturbances in the pulsating jet mode make it possible to reduce the integral temperature by increasing the average flow velocity near the wall and compensate for the undesirable effect of flow separation. The genetic programming algorithm makes it possible to find a self-oscillating regime during jet disturbance with feedback, which improves local heat transfer on the wall not worse than in the case of a forced periodic disturbance.

The problem of angular orientation of a moving object using measurements of a strapless inertial navigation system (SINS) and a satellite navigation system (SNS) is solved in the general formulation with the most general assumptions about the nature of the angular motion of the object and the probabilistic characteristics of interference from inertial measurements. The solution is obtained in the form of an extended Kalman filter using the directional cosines of rotation in the inertial coordinate system as the estimated orientation parameters, and the vector of measurements of the SNC and the accelerometers of the BINC as the observation vector. An example is given illustrating the high stability and convergence rate of the process of estimating the selected parameters of the angular orientation of a moving object.

Theoretical studies of the dependence of the optimal thickness of a single-layer antireflective coating of SiO₂ on a silicon photodiode on the characteristics of light incident on the photodiode have been carried out. It is found that the optimal thickness of a single-layer antireflective coating of SiO₂ for various angular intensity distributions increases the quantum efficiency of the photodiode up to 1.1 times compared to the classical single-layer antireflective coating with a thickness of λ/4n, which is an optimal coating in the case of normal incidence of monochromatic light.

Experiments on testing long-term stability of metrological parameters of the CLWS-300 model laser pattern generator used in the technological process of production of goniometric equipment have been carried out. It is shown that the CLWS-300 model laser pattern generator retained the ability to reproduce its indicators practically unchanged over an interval of 18 years.

A coherent fiber optic transmission system for OFDM signals is considered. The channels are formed using spectrally efficient modulation formats - QPSK and M-QAM. It is shown that the nonlinear phase noise arising in the optical path is converted into the amplitude noise and, after mixing with the noise of optical amplifiers, leads to a decrease in the signal quality index. Evaluation formulas are given for determining the noise immunity of channel signals using the Q-factor.

The Fraunhofer diffraction phenomena in coherent light on an extended object of constant thickness in the form of a volumetric asymmetric edge with a bevel and a flat reflecting (gray) inner surface of the object, characterized by the modulus of the amplitude coefficient of light reflection and the phase shift in the reflected wave, are investigated using the model of equivalent transparencies. It is shown that the field in the far zone can be represented in the form of two components: transmitted and reflected, the former corresponding to diffraction of light at an absolutely absorbing asymmetric edge, and the latter describes diffraction phenomena at a volume structure in the form of a biplanar slit illuminated by a plane light wave. On the basis of a constructive approximation of the Fresnel integral function, an expression for the spectrum of the object is obtained in analytical form, which allows studying the behavior of fields in the far-field zone. It is shown that, in the case of a large object obliqueness, the main contribution to the field is given by the reflected component. Methods of determining the geometric parameters of the object by measuring the position of the central maximum of the reflected component and its effective width are proposed.

The article considers the development of a near-wall separation vortex, arising at a supersonic flow around the external dihedral angle due to the pressure drop between its faces, in the range of angles of attack α = 0.5° - 6°. The processes of origin and development of separation and secondary vortices at the angle increase are investigated in detail. Particular attention is paid to the flow structure change in the vortex location zone. A clear violation of the flow self-similarity in the front part of the model in the zone of vortex system formation is shown.

The results of experimental and computational studies of the processes of hydrodynamics and heat transfer of a swirling flow, heated by the counter coolant flow in the heat exchange channel under standard technological parameters of a nuclear power plant are presented in this paper. The temperature field of the heat exchange channel as a whole and the coefficient of hydraulic resistance of channels with twisted tapes of a constant swirl pitch were obtained in experiments. The numerical study was carried out using the domestic software package LOGOS and the Ansys CFX complex. The simulations were performed using the k-ω SST turbulence model, corrected for streamline curvature and rotation. Two versions of the calculation grid were developed. A comparative analysis of the calculated and experimental values of the hydraulic friction coefficient, the swirling flow temperature, and the heat transfer coefficients from the wall to the swirling flow was carried out. The analysis allowed identification of the strengths and weaknesses of the calculation methodology implemented in the domestic package. Deviations of the obtained values were compared. There is good agreement between the calculated and experimental data, as well as with the data based on generalized dependences. One of the most important conclusions of the study is the need to modernize the process of solving the coupled heat transfer problem in the LOGOS package to expand the range of problems to be solved

The ignition of hard coal grades DG, G, Zh, and K under the action of laser pulses (1064 nm, 120 µs, 1.3 J) was studied for the fractions of microparticles with a narrow size distribution in the range of 0.25-44 µm. The kinetic characteristics of the glow of samples from the entire size range were measured for each coal rank. Three stages of ignition are distinguished for each fraction. The duration of the first stage coincides with the duration of the laser pulse. The duration of the second takes a time interval of 10-15 ms (DG, G and Zh coal ranks) and 3-5 ms (K coal rank). The duration of the third stage is 60-80 ms (DG, G, and G coals) and 20 ms (K coal rank). It has been established that the threshold ignition energy densities (ignition thresholds) at all three stages depend non-monotonically on coal particle sizes. The minimum values of ignition thresholds at all three stages are achieved at particle sizes equal to 2.2 (for DG rank coal), 4.0 (for G rank coal), 0.7 (for Zh rank coal) and 2.0 µm (for K rank coal). Using the results of the proximate analysis of coals, the observed dependences of critical energy densities on the size of coal particles are interpreted.

Two methods for the transition of aqueous solutions of polyvinyl alcohol (PVA) from the liquid state of aggregation to the solid state are considered. Freezing an aqueous solution of PVA at a negative temperature and subsequent thawing at a positive temperature result in the formation of rubber-like cryogels. Another way is chemical crosslinking of kinetically individual PVA macromolecules to spatial networks having elastic properties. Sodium tetraborate was used to structure aqueous PVA solutions. The rheological properties of a two-component aqueous solution of PVA were studied. The study shows that the polymer solution exhibits the properties characteristic of non-Newtonian liquids. The kinetics of gelation of the products of chemical structuring of aqueous PVA solutions with an aqueous sodium tetraborate solution was studied. It is shown that viscosity increases with time as a consequence of chemical interaction. The mechanical properties of carbon-containing composite materials obtained by various methods have been investigated. It has been determined that the most durable materials are those formed by the cryotropic method and those chemically structured after cryogenic treatments. The stress-strain and moisture-resistant properties of carbon materials enable their use as fuel briquettes with a minimum amount of a binder. They can also serve as high-energy fuels for domestic and industrial purposes. The chemical method of structuring a PVA solution can be used for dust control in coal mines.

The procedure for obtaining humic (HA), hymatomelanic (HmA) and fulvic acids (FA) that allows achieving their high yield has been developed and tested with the brown coals of the Kansk-Achinsk and the South Ural basins. The highest yield of humic substances is achieved for naturally oxidized brown coal of the Tisul deposit: HA - 60.9 %, HmA - 11.3 %, FA - 9.6 %. The composition of native brown coals, as well as HA, HmA and FA obtained from them, was studied using proximate and ultimate analysis, FTIR spectroscopy and ¹³C NMR (CPMAS) spectroscopy. It is established that the chemical and structural-group composition of HA, HmA and FA has significant differences. The samples of HmA and FA are characterized by relatively high content of oxygen-containing aliphatic groups with the predominance of carboxylic acids and esters in comparison with HA. Higher content of carbon, hydrogen and aromatic fragments is characteristic of HA. The samples of HmA and FA have similar elemental and structural group composition, however, HmA has a higher content of carbon and aromatic fragments.

Integrated studies of green coke have been carried out by means of X-ray diffractometry, electron microscopy, electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR). It is determined by EPR spectroscopy that two types of radical structures are present in the samples: low-molecular aromatic radicals and conjugated polyaromatic structures in which the unpaired electron is delocalised. Analysis of line shapes in the EPR spectra reveals differences between the green coke samples under investigation. EPR is shown to be highly sensitive method allowing one to follow the changes of molecular structure during the production of green coke. The results obtained in the work with the help of EPR are in good agreement with the results of NMR spectroscopic studies. It is concluded that evaluation of the molecular structure of intermediate coking products is necessary to improve the composition of initial raw material and technological operations.

The article reports the results of the study of the morphology, porous structure and electrical capacitance characteristics of highly porous carbon matrices (HPCMs) obtained from coal raw materials with different degrees of metamorphism and nanostructured composites (NSCs) based on them, the surface of which is decorated with gold or manganese oxide nanosized particles (NP), accumulating electrical charge during polarization in the electrolyte via two mechanisms (formation of an electrical double layer (EDL) and involvement of pseudo-capacitance component during Red-Ox reactions on electrodes). The samples of HPCMs were obtained by high-temperature (800 ^oC) alkaline activation (the mass ratio KOH/C = 2 : 1) of fossil coal from the coal basins of the Kemerovo Region and the Republic of Sakha (Yakutia): CAK - based on anthracite of the Kiyzasskiy open-pit mine (Kuzbass), with the highest coalification degree; CBK - based on boghead (a kind of sapropel coal ) from the Taymylyr deposit (Yakutia) with the lowest degree of metamorphism; CDK - based on long-flame coal (Kuzbass) occupying an intermediate position in the metamorphism series. Results obtained by scanning electron microscopy, small-angle X-ray scattering in combination with sorptometry showed that the NSC morphology is largely determined (except for submicron aggregates) by the porous structure of the matrices. The shape of cyclic voltammetry (CVA) curves for HPCMs CDK, CBK and Au-NP filled NSC based on them indicated a significant contribution from EDL into capacitance; the contribution of pseudo-capacitance is observed for the composite MnO_x/CDK electrode. The features of CVA curves for microporous CAK HPCM and NSC based on it are probably caused by hindered diffusion. The specific electrical capacitance is higher as a result of the polarization of CDK and CBK HPCM with large proportions of mesopores, as well as NSCs on their basis, than that resulting from the polarization of microporous CAK and the corresponding composites. For all three HPCMs, the introduction of fillers causes an increase in the electrode capacitance. The effect is more significant for NSCs obtained from hard coals with a low level of metamorphism (an increase up to 1.8 and 1.6 times with respect to the capacitance of initial matrices for NSCs based on CDK and CBK, respectively, according to the impedance measurement data), which is due to a decrease in the active resistance and the charge transfer resistance of the cells, and, in general, to the active component of the impedance.

The morphology of nanoparticles, structural-phase properties, and phase transformations that occur during heating in the nanostructured CoPt and CoPd systems rich in precious metals, obtained by co-reduction of aqueous precursor solutions by hydrazine hydrate, were studied by X-ray phase analysis and X-ray structural analysis, small-angle X-ray scattering, and high-resolution transmission electron microscopy. The results obtained are of interest for the development of the fundamentals of materials science of bimetallic nanoalloys, and provide a key to understand the processes of the formation of FePt, CoPt and FePd nanoalloys while heating intermetallic compounds with a highly ordered structure L1₀, which possess record-setting magnetic and magneto-optical properties.

The work is concerned with the development of a new type of iron-containing catalyst (Ct) based on lignin for the hydrogenation of carbon monoxide. Catalytic systems were obtained by hydrothermal synthesis and studied using a set of physicochemical methods (Fourier transform IR spectroscopy, Raman spectroscopy, low-temperature nitrogen adsorption, elemental analysis, atomic absorption analysis, X-ray phase analysis, X-ray photoelectron spectroscopy, transmission electron microscopy). Brunauer-Emmett-Teller (BET) surface area analysis, elemental analysis, atomic absorption analysis, X-ray fluorescence (XRF), transmission electron microscopy (TEM). It is shown that the formed catalysts are fine-grained, non-pyrophoric, non-hygroscopic, black powders. The catalytic systems are determined to exhibit high activity in carbon monoxide hydrogenation: the conversion is close to 100 %, the productivity with respect to С₅₊ hydrocarbons reaches 131.6 g/(kg Ct ∙ h).

The effect of hydrothermal carbonisation temperature (190-250 °C) on the properties of biochar produced from hydrolytic lignin was studied. Biochar was investigated using a set of physicochemical methods, its elemental, proximate and thermal analysis was carried out. It is shown that an increase in the temperature of hydrothermal treatment has a negative effect on biochar yield but allows obtaining a more thermally stable product with fuel characteristics comparable with those of brown coal.

Ni-, Co- and Ni–Co-containing catalysts for steam reforming of isobutanol were obtained by biochar impregnation with water-alcohol solutions of metal salts. Biochar was synthesised by the hydrothermal carbonisation of cellulose with subsequent thermal treatment of the obtained materials under the conditions of limited oxygen access. The catalysts were characterised using a complex of physicochemical methods (IR spectroscopy, BET, temperature programmable desorption of ammonia, scanning electron microscopy in combination with local electron microprobe analysis, X-ray phase and X-ray fluorescence analysis). It is found that the sample 2.5Ni-2.5Co/C (where the number before the metal symbol means its mass content calculated for the mass of reduced catalyst, %) provides a high yield of hydrogen (58%) from isobutanol reforming.

To develop an effective catalyst for the resource-saving conversion of coal-industry methane into hydrogen-containing gas, the materials Ce_0.2Ni_0.8O_1.2/Al₂O₃ were synthesized, their physicochemical and functional properties were studied depending on the nature of the precursors of active components (nickel(II) nitrate hexahydrate, nickel(II) ammonium oxide) and promoters (cerium(III) nitrate hexahydrate, ammonium cerium(IV) nitrate). It is shown that the nature of the precursor affects the textural and structural characteristics of the samples, their catalytic activity in the steam-carbon dioxide reforming of methane and resistance to the formation of carbon deposits. The optimal composition of precursors (nickel(II) nitrate hexahydrate, cerium(III) nitrate hexahydrate) has been established, the use of which in the synthesis of the Ce_0.2Ni_0.8O_1.2/Al₂O₃ catalyst ensures a decrease in the average particle size of the Ni active component (25 → 6.5 nm) and the degree of catalyst carbonisation (2.9 → 0.5%), high hydrogen yield (95%) at 800 °C in the steam-carbon dioxide reforming of methane.

The effect of the temperature regimes of hardwood sawdust thermochemical treatment (hydrothermal carbonization and torrefaction) on biochar properties and combustion characteristics are investigated. The mass yields of biochars were considered from the viewpoint of the processes that take place during thermochemical treatment, along with the changes in the elemental composition resulting from these processes. The optimal method and temperature regime of thermochemical treatment were determined. The effect of the method and temperature of sawdust thermochemical treatment on the composition of gaseous products from biochar combustion was assessed by FTIR spectroscopy combined with thermogravimetric analysis. Two main stages of biochar combustion were detected: the phase of removal and combustion of volatile substances (up to 400 °C) and the phase of semi-coke combustion (above 400 °C). The analysis carried out by means of FTIR spectroscopy during combustion allowed us to determine the released components of the gaseous mixture and to observe thermochemical decomposition of biochar components in the real time mode. Investigation of biochar combustion showed that an increase in sawdust processing temperature reduces the formation of gaseous products at the first stage of combustion and promotes an increase in the amount of carbon dioxide at the second stage.

Adsorption treatment of industrial wastewater and reservoir water from toxic metals can reduce the anthropogenic load on water bodies. The efficiency of using an adsorbent obtained on the basis of local mineral raw material, namely burnt rock from the Erunakovskoe coal deposit (the Kemerovo Region), to remove heavy metal ions from aqueous solutions is shown. The kinetics of cadmium ion extraction from aqueous solutions, the adsorption models of Freundlich, Langmuir and Dubinin-Radushkevich, and their significance for the description of heavy metal ion recovery from aqueous solutions using burnt rock were studied. The dependence of adsorption on the acidity (pH) of the medium has been established. A maximum adsorption capacity of 30 to 40 mg/g was achieved at pH 12.0. Chemical modification with alkali (NaOH) at pH 12.0 leads to an increase in the degree of cadmium ions extraction. Within the studied concentration range, the Freundlich and Langmuir isotherms are more consistent with the experimental data on the equilibrium adsorption of metal ions on burnt rock, compared to the Dubinin-Radushkevich model.

A mesoporous carbon sorbent modified with sulphosalicylic acid by adsorption from aqueous solutions has been synthesized. The optimal modification parameters were selected: the ratio, concentration, the duration of impregnation and heat treatment stages, and pH. The physicochemical properties of the samples have been studied: textural characteristics, qualitative and quantitative composition of surface functional groups, the amount of applied modifier, adsorption and desorption properties. The adsorption characteristics of the studied samples with respect to organic dyes methylene blue and methanyl yellow are determined. It has been established that during desorption for 48 h, ~68 and ~82% of the initial concentration of sulphosalicylic acid applied to the sample pass into the aqueous solution, modelling the intestinal medium and into ethanol, respectively. In this case, a decrease in the pH of the initial solutions by 6 units is observed. High antibacterial properties of the modified carbon sorbent towards Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae have been established in vitro .

Compositions for the formation of three-component elastic cryogels based on the aqueous solutions of polyvinyl alcohol (PVA) and potato starch are proposed. It is shown that the viscosity of aqueous solutions depends both on the kind of polymer and on the total content of polymers in the system. The elasticity modulus of three-component cryogels depends on the concentration of starch in them and increases from 5 to 15 kPa with the addition of starch in the amount of 1-5 wt%. By introducing a dispersed material (soil) into the matrix of two-and three-component cryogels, due to the high adhesion of the polymer to the filler, the filled cryogels were obtained, with the elasticity modulus 16 times higher than that of cryogels without the filler. The introduction of potato starch in the amount of 5 wt% into PVA cryogel caused an increase in the time of its complete drying by 24 h, and an increase in its destruction during exposure in water by 5% within a week. Two-component cryogels exhibited sharply different types of behaviour during storage in water: PVA cryogel did not lose its mass, while mass loss by the cryogel of potato starch was 11% within a week. A decrease in the mass of three-component cryogels by 75-89% due to the loss of moisture and destruction was demonstrated in the soil test under the action of aboriginal soil microflora. The mass loss by the two-component cryogel based on PVA was 60%. Soil testing for phytotoxicity after the destruction of three-component cryogels revealed a decrease in the germination capacity of white mustard ( Sinapis alba L.) by 2-10% with respect to the reference experiment, depending on starch content, while for the reference two-component PVA cryogel the corresponding decrease was by 18%. Cryostructuring of the upper soil layer by PVA cryogel caused an increase in the dry above-ground mass of plants by 3.2% in comparison with the reference, while the cryogel with potato starch caused an increase by 7.1%, and cryogel based on PVA and potato starch gave 9.4%.

Methanation process, or selective hydrogenation of carbon oxides, is described. The chemical foundations of the process and the features of the formation of reaction products are considered, depending on the catalyst used. The advantages of catalytic systems based on carbon materials and disadvantages of the catalysts on oxide substrates for the production of synthetic methane are evaluated. Nickel-containing carbon catalysts based on birch activated carbon and microcellulose were obtained by incipient wetness impregnation and hydrothermal synthesis, and proposed for the selective hydrogenation of carbon monoxide (СО). The synthesized samples were studied by optical emission spectroscopy with inductively coupled plasma, low-temperature nitrogen adsorption, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, thermogravimetric analysis. The influence of the substrate and the method of catalyst synthesis on CO conversion and methane yield from the selective hydrogenation of CO was studied, and the optimal size of NiO and Ni(OH)₂ crystallites, the precursors or the active phase, was determined. It is shown that the best carbon monoxide conversion and methane yield from methanation reaction are achieved in the presence of nickel-containing microcellulose-based carbon sample obtained by hydrothermal synthesis.

An algorithm is presented for identifying potential production chains for resource-based regions relying on patent analytics, in particular, applying patent landscape report creation approaches and peer review, which in the future, after their economic justification, can become the foundation for the new strategy of innovative development for a resource-based region. Within this strategy, it is planned to create new high-tech economy sectors in the field of coal mining and coal processing.

The breadth of the use of activated carbons (AC) in many areas of economy, ecology and defense of the country is shown. The unique physicochemical characteristics of AC are denoted, and their modern determination is presented. It is established that the Russian Federation is currently lagging far behind industrialised countries in the output of AC production. Attention is paid to the coals of Kuzbass as a raw material for the large-tonnage production of AC. Various technologies for manufacturing active coals on this basis are considered.

The purpose of this study is to establish the genesis and conditions of formation of different types of sediments in the permafrost area of Baydara Bay. Perennially and seasonally frozen and perennially and seasonally cryotic sediments have been identified on the basis of temperature measurements in core samples obtained during geotechnical drilling and thermal cone penetration tests along the profile crossing the bay. We suppose that permafrost was formed in this area in the course of epigenetic freezing during the Sartan regression. Seasonally frozen ground of the seafloor is subdivided into two types. The first type is characteristic of coastal shallows, where landfast ice contacts the seafloor. The second type is formed in the seaward part of the water area during the cold season, when the temperature of near-bottom seawater drops to values below the freezing point. Perennially cryotic (but unfrozen) ground is formed below the depth of the 0° isotherm traced during the warm season. Seasonally cryotic ground above this isotherm has above-zero temperatures in the warm season. In the winter season, under the impact of subzero temperatures of seafloor water, it is transformed into the cryotic or seasonally frozen state.

This study is devoted to substantiating the theoretical dependences of the porosity of the unconsolidated part of pressure ice ridges on the distance from the edges of the sail or keel. According to the crushing theory, particle sizes in crushed material follow a lognormal distribution. Ice blocks in unconsolidated parts of ice ridges can be considered as such crushed material. Information on the sizes of ice blocks and voids has been obtained from data on the penetration rate of thermal drilling of ice ridges and grounded ice ridges (stamukhi). It is argued that the average porosity of an ice ridge as calculated from thermal drilling data for a given depth is an estimate of the probability of finding a void at this depth. A statistical model of the depth-wise porosity distribution in the keel and sail of ice ridges as granular media is suggested. The average vertical size of voids decreases with distance from the edge of the keel or sail according to a logarithmic law, and the average vertical size of ice blocks remains approximately the same. The average porosity of the unconsolidated sail and keel changes according to a lognormal law with distance from their edge, and the porosity of the sail is approximately two times less than the porosity of the keel.

In recent decades, glaciers in Northern Siberia and the Far East have been influenced by climate change, especially small forms of glaciation. This process is also typical for the glaciers of the Koryak Highlands. To assess the dynamics of glaciation in this region, data from CORONA (1972), Sentinel-2 (2019) images, and the USSR Glacier Catalog (mid-1960s) were used. The USSR Glacier Catalog of the Koryak Highlands was compiled based on data from topographic maps and aerial photographs. The number of glaciers included in this catalog is almost 2.5 times higher than the number of glaciers identified on satellite images. For the studied region, the new electronic catalog Glaciers of Russia records 890 glaciers with a total area of 296.29 km². This region is abundant in rock glaciers, and apparently the USSR Glacier Catalog (and perhaps the new electronic inventory) mistook many rock glaciers for living glaciers at the time of its compilation. Therefore, the authors made a new estimate of glacier areas using CORONA images. The discrepancies between the areas of glaciers indicated in the Catalog and identified on satellite images were determined for groups of glaciers.

We performed geophysical studies to determine the structure of the frozen layer around and below the Uomullyakh-Kyuel Lagoon, the lagoon itself being a reference landform sculpted by thermokarst and thermal abrasion of the sea shoreline. The main purpose of the study was to determine talik depth under lagoon or the position of the subaquatic permafrost boundary. We performed electromagnetic and electrical studies with transient electromagnetic sounding and electrical resistivity tomography from lagoon ice during winter period and from water surface in summer. We matched borehole section data with temperature data from this same borehole and also with surface geophysical data. This comparison showed patterns of modern and relict taliks in the form of low electrical resistivity layers. We demonstrate that modern talik has developed to the depth of 30 m. At the same time, the relict talik is located between depths of 80-100 m, which correlates with data acquired by other researchers. We suggest that relict talik has a hydrological connection to the strata located under the seafloor; therefore it is seen clearly on geoelectric cross section. The lake that formed the relict talik had a size of at least 1450 by 900 m. Electrical resistivity tomography data acquired from the lagoon surface shows fragments of boundaries between frozen and unfrozen permafrost. Numerical modeling shows that electrical resistivity tomography quantitatively underestimates resistivity of the frozen permafrost by 5 to 10 times. In the subaerial-subaquatic transition zone, we track a gradual descent of the permafrost upper boundary and map a permafrost overhang, which sometimes appears beneath shallow water bodies. We suggest that gradual decrease of electrical resistivity in the direction from the seashore to the sea basin corresponds to the amount of salt transported into sediments and increase in their temperature.

Cryosophy can be considered as conceptual meta-views of cryology. Its main goals are the interdisciplinary integration of ideas about cold and creation of conceptual models ensuring the holistic perception of the cryosphere. To achieve these goals, the scientific understanding of the cryosphere as a system, which would rely on modern general theoretical approaches that have overcome logical empiricism on the way to holism with its epistemological principle “the whole is always more than just the sum of its parts”, is of major importance. One of the crucial factors that prevented the formation of a holistic scientific picture of the Earth’s cryosphere during the 20th century was that the cold shell of the planet, which consists of the glaciosphere, cryolithosphere, and atmosphere, was studied by different scientific disciplines. Only at present the scientific community has made the first steps in considering the cryosphere as an almost one hundred-kilometer sphere around the Earth, the near-surface and subsurface parts of which occupy significant territories of continents and oceans. Given similar understanding, the Earth’s cryosphere can be interpreted as a global geosystem, which penetrates significant areas of commonly accepted geospheres-atmosphere, lithosphere, and hydrosphere, as well as soil horizons and largely determines the matter and energy exchange between them. The examples presented in this paper indicate that the key to understanding the unity and diversity of the world of cold is the philosophical comprehension of the cryosphere as a complex system. Such an understanding should make it possible to overcome logical empiricism and reductionism on the way to holism.