Home – Home – Jornals – Avtometriya 2025 number 1

Porphyritic amphibole-plagioclase andesites at the southern margin of the Utanak ultramafic massif (Stanovoi superterrane, Russian Far East) show low yttrium and ytterbium contents and high Sr/Y and La/Yb ratios typical of adakites. Microinclusions in these volcanic rocks are Cu-Ag-Au alloys, native silver, composites of gold and silver with Cu, Zn, In, Mn, Ni, and Mo minerals, as well as microparticles of platinum, silver sulfides and chlorides, pyrrothite, chalcopyrite, barite, tungsten oxide, crocoite, and cassiterite. The structural features of some microinclusions and their association with primary amphibole and plagioclase suggest their magmatic origin, while other microinclusions hosted in the quartz-chlorite- K-feldspar groundmass formed during later metasomatism. The Utanak adakites are characterized by elevated gold contents (up to 134 ppb) and, together with other manifestations of Mesozoic adakitic magmatism within the Stanovoi superterrane (Il’deus, Lucha, and Gabbrovyi massifs), are classified as ore-bearing (fertile) adakites according to geochemical criteria. We suggest that common association of adakitic magmatism with large porphyry, epithermal, and skarn deposits at convergent plate boundaries is related not only to the high water content and the oxidation state of adakitic magmas but also to the initial enrichment of the latter in various ore components.

The Russian sector of the Eastern Arctic is characterized by large basins with thick sedimentary filling, primarily on the shelf and continental slope of the seas of the Arctic Ocean. A number of geological, geophysical, and geochemical features point to a hydrocarbon potential. At the same time, the age and composition of the sedimentary infill of the shelf basins have been controversial until now due to the lack of wells drilled in the shelf area. Six stratigraphic wells were drilled with core sampling in the eastern Laptev Sea (Anisin-Novosibirsk block owned by Rosneft) with a depth of 100 to 199.5 m during the Rosneft Stratigraphic Drilling in Arctic (RoSDAr) project in 2021. The results of complex biostratigraphic studies of the core show that the oldest strata in the well sections are Upper Barremian - Lower Aptian deformed silty mudstones (folded basement assemblage) overlain with angular unconformity by sands, silts, and clays of the Paleocene. The wells also penetrate the Eocene, Oligocene, and Miocene-Quaternary clastic rocks. A comprehensive analysis of stratigraphic drilling and seismic data refines the geological models of the region and provides better understanding of its hydrocarbon potential. The data show that Cenozoic strata play a more significant role in the sedimentary cover of the Laptev Sea than was previously assumed.

This study contributes to the development of C, O, and Sr isotope chemostratigraphy of the upper Berriasian-Valanginian of Arctic Siberia and to the improvement of the Boreal-Tethyan correlation scheme based on it. Results of an isotope-geochemical study of belemnite carbonate material from the Anabar and Boyarka river sections and the Nordvik Peninsula section (Ryazanian-lower Hauterivian) are presented. The following three phases of the global Weissert event are identified: a rapid increase in δ¹³C at the turn of the early and late Valanginian, stabilization of δ¹³C in the late Valanginian, and a smooth decrease in δ¹³C since the end of the Valanginian to the earliest Hauterivian. It is suggested by the δ¹⁸О data from the Neocomian formations of Siberia that the climate cooling associated with the Weissert event is negligible. The resulting ⁸⁷Sr/⁸⁶Sr values for the Boyarka and Nordvik sections in combination with bio- and magnetostratigraphy indicate that the base of the upper Berriasian falls into the middle part of the Hectoroceras kochi ammonite Zone of the Ryazanian Stage. It is revealed that the top of the Ryazanian is located below the base of the Valanginian. The interval between these boundaries in Siberia corresponds to the lowermost part of the Neotollia klimovskiensis ammonite Zone. The age of the ammonite zones of the Boreal (Siberian) standard of the lower Valanginian is clarified. It is reliably determined that the Homolsomites bojarkensis ammonite Zone belongs to the lower Hauterivian rather than upper Valanginian, which resolves the issue that has been the subject of lengthy discussions.

The article discusses modern methods of quantitative assessment of the elements of hydrocarbon resource structure in large oil and gas (petroleum) basins. The assessment is based on the law of mass distribution of hydrocarbon accumulations, i.e., the truncated Pareto distribution. The procedure developed is used for: estimation of the truncated Pareto distribution parameters and cumulative hydrocarbon volumes concentrated in pools, prediction of their number and size distribution and total resources within each size-class interval; simulation of spatial distributions of hydrocarbon accumulations with transformation of a population of HC pools into a population of fields; prediction of the number and size-class distribution of total HC resources in pools and fields, and fields distribution by the number of HC pools. The involved analytical approach based on the simulation mathematical modeling is described.

Oil and bitumen shows with previously unknown hydrocarbon biomarkers - 9-methyl, 8-14-secohopanes - were encountered in the sections of hydrogeological wells on the northeastern slope of the Aldan anteclise. Shows of biodegraded asphaltites are confined to the cavernous horizon in the middle Cambrian limestones of the Tankhai Formation. The relatively high residual concentrations of the “new” biomarkers are due to their very high resistance to biologic oxidation processes. Geologic materials and geochemical data on the studied naphthides suggest that in the region under consideration there is a typical oil deposit sealed in the “head” of the cavernous horizon by highly viscous bitumens.

This paper presents the results of constructing a model of the geoelectric structure of Northern Vietnam obtained by 3D inversion of magnetovariational tippers calculated for 13 values of variation periods in a range of 40-10047 s at 12 points where geomagnetic variations are recorded. Inversion is performed using the ModEM software, which makes it possible to construct a model in a 400 × 400 × 200-km spatial region with the center at the Hanoi Observatory (PHU). The resulting model of the geoelectric structure contains two regional blocks separated by the Red River fault region. A conductive block is located in the southwest of the fault region, and a high-resistivity block is located in the northeast. The boundary of the blocks, inclined to the northeast at an angle of about 45°, is visible to a depth of 150 km. The conductive block occupies the region between the Red River and Song Ma faults. Its western boundary could not be localized due to insufficient data in this region. Highly conductive local blocks stand out against the background of the regional conductive block. They usually gravitate toward the faults and are located in a depth range of 10-20 km with a slight inclination to the west on latitudinal profiles and to the south on meridional ones. In a depth range of 12-14 km, they merge into one highly conductive band extending in the northwest and marking the Red River fault system connected to the Gulf of Tonkin waters. Also, there are more massive highly conductive blocks in depth intervals of 20-50 km, which are often associated with upper crustal ones. There is a highly conductive block observed on the latitudinal profile, passing through the central region of the Hanoi Basin, and steeply dipping to the east (75°) to depths of more than 100 km. The deep geoelectric features of the Red River fault system are compared with the geoelectric section under their continuation in Southern Tibet in the adjacent territory in China.

The article presents a practical approach to the geological and geophysical spatial data collection and preliminary processing to use in machine learning models for geophysical applications. According to the established principles for estimating efforts in data analysis, which are confirmed by the results of surveys among specialists, this stage is viewed as major time and resource-consuming, amounting up to 80% in total volume of data analysis for a hypothesis testing project. The paper focuses on creating a consistent data set that integrates geological and geophysical information on a given region. We consider problems of different sources in the geodata representation to be related to their format (vector/raster), scale, type of attribute information (quantitative/qualitative) and their availability. The algorithm formalization and synthesis for combining geospatial data and converting them into quantitative vectors is a critical aspect. Combining various data draws on the concept of neighborhood fitting in with the data selection techniques and data consolidation strategy. The paper presents the general architecture of the software and hardware complex which includes a module for data collection and transformation in Python using the Pandas library, a data storage system based on the PostgreSQL DBMS (Database Management System) with the PostGIS extension. It is shown that for the considered class of problems in geophysics, it is sufficient to use a relational DBMS for data storing and processing. If the problem dimension increases, it is proposed to use the Big Data technology based on Apache Hadoop for scaling the system. A practical application of the proposed approach is demonstrated as results of data collection for the Caucasus region and eastern sector of the Russian Arctic. Based on the prepared data, experiments were carried out using machine learning models for recognition of locations of potential strong earthquakes and for sensitivity estimation of several geophysical features of these regions. The article presents the experimental results and evaluation of their efficiency.

Records obtained at seismological stations contain information not only about earthquakes, explosions, but also from various other sources of seismic waves. The sources of such waves can be various buildings and structures that vibrate with their own frequencies. Seismologists can understand the registered wave field, identify the waves from these sources and characterize them. It is possible to implement seismic methods of remote control over changes in the technical condition of various objects. Contemporary hydraulic structures were built a long time ago and aging processes in them lead to destruction of materials and formation of cracks, so these objects require continuous monitoring of their condition. The aim of this work is to investigate the possibility of determining the occurrence of cracks in the body of the dam of the Sayano-Shushenskaya hydroelectric power plant by analyzing its natural frequencies depending on the filling and drawdown of the reservoir. For this purpose, we placed a seismic station several kilometers away from the object of study. With the help of this station, as well as with the help of the seismological data obtained at the seismic station “Cheremushki”, located 4.5 km from the HPP, for 20 years, works were carried out to study the possibility of determining the natural frequencies of the dam with high accuracy when they change in time. The possibility of controlling the physical parameters of structures and operation of various units of the HPP for a long period of time was demonstrated. Examples of determination of frequencies of high- and low-quality signals are considered.

Teleseismic receiver functions (RF) were extracted from data collected at eight short-period, three-component seismic recording stations over the Guelma-Constantine Basin, northeastern Algeria, to improve the understanding of crustal structure and geodynamic processes. The H -κ stacking method was used to determine the Moho depths and average v_P/v_S ratios at each station. Careful linear inversion of RF was performed to determine the most appropriate average shear-wave and P -wave velocity profiles at each site. Both methods have yielded highly congruent results, with Moho depths showing robust correlations with previous seismological and geophysical studies. The previously observed pattern of the increasing Moho depth from north to south in the Tell Atlas has been confirmed. Furthermore, the identified transitional nature of the Moho in the Constantine Basin is consistent with a recent study. In addition, we identify a low-velocity zone (LVZ) at approximately 20 km depth within the southern Guelma Basin, confirming previous results in the Constantine Basin and suggesting an eastward elongation of the LVZ, at least into the southern periphery of the Guelma Basin. Examination of data from the northern tip of the Hammam Debbagh-Roknia NW-SE fault, the western boundary of the Guelma pull-apart basin, revealed a shallow Moho depth (22 km), less than the basin average depth of 25 km. The LVZ observed in the lower crust (12 km) suggests the presence of partial melts, consistent with gravimetric and chemical analyses of hydrothermal sources in the area. The extensional tectonic activity along this boundary, coupled with the low-viscosity zone and low average v_P/v_S ratio, is potentially associated with delamination processes. The effectiveness of our approach underscores its potential as a viable alternative or complementary method for investigating variations in the Moho depth.

In this study, we consider the dynamics of interaction of near-IR electromagnetic radiation with a space charge wave (SCW) propagating in the volume of a cylindrical n - GaAs waveguide. A possibility of phase modulation of a slow electromagnetic wave (like the whispering gallery mode) with a depth of 10 to 30 radians is demonstrated. It is found that the phase-modulated radiation splits into a sequence of ultrashort pulses during further propagation in the optical waveguide. The repetition rate of the formed pulses coincides with the frequency of the SCW realized in the waveguide. The peak power of the generated pulses exceeds the average power of the radiation introduced into the waveguide approximately by three orders of magnitude and can reach values of 20-50 W. The numerical analysis shows that the optimal length at which optical pulses are formed outside the waveguide depends on the amplitude and frequency of the modulation of the concentration of free charge carriers associated with the propagating SCW.

In this study, a two-core fiber based on tellurite glass with interacting single-mode cores is fabricated, and the linear and nonlinear propagation of ultrashort pulses is investigated. In the fabricated fiber, the effect of nonlinear optical switching of ultrashort pulses at a wavelength of 1.56 μm is experimentally demonstrated, which manifests itself as energy redistribution between the cores at the fiber output with an increase in the energy of the input pulse launched into one of the fiber cores. The effect is observed at relatively low pulse energies of less than 2 nJ, which is of interest for the design of saturable absorbers for mode-locked fiber lasers.

The issue of the existence of a reverse flow behind the Mach disk in the first shock cell of a supersonic underexpanded jet is numerically studied on the basis of solving the Navier-Stokes equations. It is shown that the reverse flow existence depends on the Reynolds number: it arises at low Reynolds numbers and vanishes when the Reynolds number exceeds a certain value. Thus, for experimental observations of this paradoxical phenomenon, it is necessary to perform experiments with jets of a sufficiently rarefied gas.

Passive intensification of heat transfer in a tube is achieved by using detachable intensifiers or changing the shape of the heat transfer surface. In this work, the intensification process was studied using spherical turbolizers located in a horizontal stainless steel channel. Experimental data were obtained during circulation of an alcohol-water mixture with a concentration of 30 wt. % at a pressure in the vessel of 0.03 - 0.04 MPa. It is shown that the efficiency of spherical intensifiers is commensurate with the efficiency of spiral intensifiers at significantly lower pressure drops.

The paper investigates the geometry and droplet size distribution of a fuel spray produced by an injection system with air-assisted (pneumatic) atomizer. Two optical research methods, based on the processing of images obtained through shadow photography, were employed. The evolution of a pulsed spray was studied using a high-speed video camera with a macro lens. Droplet size distributions were studied using a camera equipped with a long-distance microscope and backlighting comprising a luminescent background screen and a pulse laser. The study was conducted for air-to-fuel mass flow rate ratios (ALR) of 1 and 0.16. The Sauter mean diameter for atomized droplets was 13 and 18 microns for the ratio values of 1.0 and 0.16, respectively.

On the basis of a complete system of acoustic equations, the evolution of acoustic disturbances in a high-temperature reactive mixture of carbon dioxide, carbon monoxide, and oxygen CO₂/CO/O in the dissociation-recombination reaction, as well as in the nonequilibrium endothermic reaction of CO₂ dissociation and exothermic reaction of afterburning of carbon monoxide in oxygen, is investigated. A realistic single-temperature Arrhenius model of chemical kinetics is used. The values of thermodynamic parameters on the trajectory of hypersonic flight in the Martian atmosphere are taken as stationary environmental conditions. For the dissociation-recombination reaction with a negative thermal effect near chemical equilibrium in the asymptotic high-frequency limit, attenuation of acoustic disturbances is shown. Under the same conditions, acoustic disturbances amplify in the nonequilibrium exothermic reaction and attenuate in the nonequilibrium endothermic reaction.

This paper presents the results of numerical simulation of a submerged jet leaving an orifice of diameter D with velocity U, when the nozzle is subjected to mechanical oscillations (vibrations) of frequency ƒ. Vibrational excitation leads to jet bifurcation at Reynolds number Re = DU/ν>50 in wide ranges of oscillation amplitude Z₀, Strouhal number St = ƒD/U , and it is similar to acoustic forcing. The obtained estimates of the characteristic jet thickness and its expansion angle α performed to study the influence of Z₀, Re, and St parameters allow identification of the optimal values St_opt of the Strouhal number, at which the splitting process is most pronounced. The previously noted effect of an increase in angle α with an increase in the excitation amplitude and saturation after some threshold values of amplitude Z₀ are confirmed. These results also indicate that with a decrease in Re, the threshold amplitude (above which saturation in a occurs) increases, and the maximum possible values of a drop significantly. The influence of Re on the optimal Strouhal number was found: with a decrease in Re from 3000 to 100, the St_opt values drop significantly.

Numerical modeling of the local flow structure and mixing process during injection of a gas-droplet wall jet into a turbulent heated air flow has been performed. The numerical solution is based on a system of axisymmetric Reynolds-averaged Navier-Stokes equations (RANS) taking into account the two-phase character of the flow. To describe the dynamics and heat and mass transfer in the dispersed phase, the Euler two-fluid approach is applied. A significant effect of the liquid mass concentration on the distribution of parameters over the channel cross-section and thermal efficiency is shown. An increase in thermal efficiency reaches 30% in the initial part of the channel and 200% in its end part in comparison with a single-phase wall air jet.

This papers presents the results of experiments and simulation on the regularities of a high speed gas-particle flow impinging a complex target under conditions of cold spry deposition. The target consists of a substrate and an installed in front partition with conical converging/diverging perforation. Numerical simulation was performed using the ANSYS Fluent code in the mode of single particles motion (without the influence of particles on the gas flow parameters). Also, the results obtained were compared with previously investigated penetration of gas-particle flow through a mask with a cylindrical perforation.

The characteristics of three-component slurry fuels, including coal, water and pyrogenetic liquid (a by-product of thermal processing of wood waste) have been experimentally studied, and the dispersion of the obtained slurries has been investigated as applied to the technology of their combustion in energy boilers. Samples of slurries for the study were obtained using a technology that includes coal mass grinding in a ball drum mill, metered mixing of components and processing of the resulting mixture on a rotary hydrodynamic cavitation generator, ensuring additional grinding of the coal mass, slurry homogenization, and mechanochemical activation of the fuel. The slurries were dispersed using a pneumatic injector with an external mixing of the slurry and the spraying agent. The average slurry droplet size in the jet after spraying was determined using the Interferometric Particle Imaging (IPI) method. The droplet velocity was recorded using Particle Image Velocimetry (PIV). The characteristics of the gas-liquid flow created by the nozzle have been obtained from the initial breakup of the liquid jet to the final state of the spray.

It is demonstrated in the paper that the range of an equilibrium SF₆ jet normalized to the nozzle diameter is independent of the dimensional stagnation temperature if the values of four dimensionless parameters (jet pressure ratio, Reynolds number based on the nozzle diameter, and two temperature factors) remain unchanged. In contrast to the equilibrium case, the range of a vibrationally excited SF₆ microjet is an essentially nonmonotonic function of the dimensional stagnation temperature.

The present study investigated the phenomenon of heat transfer when a liquid droplet evaporated on a heated structured surface made of black silicon and smooth glass with a graphite coating. Water and volatile dielectric liquid HFE-7100 were used as the working fluids. The temperature fields were studied when shooting with a thermal imager from the top and from the side. A convective flow inside the droplet caused by the Marangoni effect was also investigated. The structures formed inside the heated liquid droplet were analyzed depending on the type of liquid. In particular, for HFE-7100 droplets, the evolution of the flower-shaped convective cells was studied in detail, and the contact line movement velocities were measured during evaporation of microdroplets.

The paper presents the experimental results on capillary liquid spreading over superhydrophilic black silicon surfaces of various morphologies created by cryogenic plasma-chemical etching. Five samples of capillary surfaces with different microstructure characteristics were made, including two hybrid surfaces combining microstructuring of different heights. The morphology of surfaces and characteristics of their wetting with water were studied, including the Wi number, which characterizes the capillary absorption of liquid. It was found that a greater height of microstructures ensures better liquid spreading. The maximum values of the Wi number are achieved on hybrid surfaces with a greater density of “high” microstructures. The prospects of using hybrid capillary surfaces to increase the critical heat flux during water boiling are shown.

This study demonstrates a process of nanoparticle crystallization in an expanding jet of high-enthalpy in-equilibrium plasma carrying the titanium particles flow (as an example) and their deposition on a substrate. The plasma source is a disk-type MHD accelerator. The transport gas with a gaseous precursor is fed to the plasma accelerator input. The flow from this MHD accelerator gains the velocity about several km per second and emerges into vacuum chamber. The generated plasma jet flows around the substrate. When the substrate is placed at the distance from the MHD exit equal to the channel width size, this arrangement produces a smooth coating on a substrate. For one order higher distance to the sample, this gas-particle flow creates a coating of nanosized crystals.

The thermal diffusivity and the thermal conductivity of solid erbium in the temperature interval of 295-1475 K have been measured using the laser flash method. Approximation equations and a table of reference values for the temperature dependence of heat transfer coefficients of the studied metal have been received. The obtained results have been compared with the known literature data. The temperature dependence of the erbium thermal conductivity is shown to be mainly determined by the electronic contribution.

The paper presents experimental data on the effect of the morphology of the superhydrophilic black silicon surface structure, obtained by plasma-chemical etching, on heat transfer during pool boiling of water. Silicon surfaces with homogeneous and hybrid microstructures are investigated. Heat transfer experiments were carried out on pre-selected microstructured surfaces with the best characteristics of capillary absorption. It is shown that the critical heat flux (CHF) for a surface with a hybrid structure is approximately three times higher than the CHF for a smooth silicon surface (660 kW/m²), reaching a value of 1914 kW/m², while the CHF for a surface with a homogeneous structure exceeds the CHF for a smooth surface by the factor of 2.4, reaching a value of 1568 kW/m². At that, the maximum recorded heat transfer coefficient (HTC) of the surface with a homogeneous capillary structure, on the contrary, is the highest (77 kW/(m²K)), almost twice exceeding the heat transfer coefficients for the unmodified surface in the region of moderate heat fluxes. The surface with a hybrid structure demonstrates a delay in boiling incipience when compared with the results for a smooth surface, but with a further increase in the heat flux it significantly exceeds the HTC for the smooth reference surface, ultimately reaching a maximum value of 45 kW/(m²K) in the pre-crisis region.

The density of a liquid mixture of lithium, sodium and potassium fluorides of eutectic composition (FLiNaK) was measured using gamma-ray attenuation technique over the temperature range from liquidus to 1010 K. Based on experimental data, an equation for the temperature dependence of density has been proposed. The obtained results on the volumetric properties of the FLiNaK melt have been compared with literature data. Using the approximation of an ideal solution, the temperature dependence of the FLiNaK density in the solid state has been calculated and the density jump during melting has been estimated.

The processes of heat transfer and phase transformations in a freshwater reservoir during the cold season are considered. A non-stationary computational model applied for determining the thermal behavior of a reservoir and the ice cover dynamics is based on the numerical solution of the Stefan problem in a generalized formulation. Climatic conditions are considered in the form of dependences of the average daily values of air temperature, wind velocity, humidity and solar radiation flux. The influence of heat fluxes and snow cover height on the reservoir temperature and ice growth dynamics is analyzed.

Developing the approach to the synthesis of polyfluorinated boron derivatives formulated as one precursor, a series of target products, tested previously using O-, N-, and C-nucleophiles, a series of potassium 4-arylthiotetrafluorophenyltrifluoroborates was obtained through the action of organylthiols in the presence of bases on potassium pentafluorophenyltrifluoroborate.

In the studies of the human habitat, similar organic substances are commonly determined summarily (group analysis). In the present work, a review of publications related to the years 2015-2023, dealing with the group analysis of hydrochemical objects and foodstuffs is presented. In both cases, a traditional and most widespread method of group analysis is the total index calculation, in spite of the metrological incorrectness of this method. The corresponding assays include measuring of generalized signals, construction of univariate calibration and rough estimation of the total content (c_Σ) of the analytes, calculated for a certain standard substance. The new group analysis instruments for hydrochemical objects are the inverted multivariate calibrations, and for antioxidant determination in foodstuffs - the interval estimates of c_Σ. These new group analysis variants lead to more correct results, however, they have not been studied in sufficient detail and are rarely used in actual practice. The application of multivariate calibrations is hindered by the labour-intensive construction of training sets, while the use of interval estimates is hindered by the intergroup signal selectivity, leading to excessively wide intervals. The trends in the development of group analysis and promising directions of future investigations are discussed.

The influence of polyisobutylene of grades P-30 and P-200 on the rheometric, physico-mechanical and dynamic properties of rubber used for manufacturing the products exposed to sea water has been investigated. The rubber compound included: butadiene-styrene DSSK-628V and chlorobutyl KhBK-139 rubbers, vulcanising agent (sulphur), vulcanisation accelerators (2,2'-dibenzthiazole disulphide, guanide F), vulcanisation activators (zinc white, stearic acid), antioxidant (N-phenyl-2-naphthylamine), softeners (rosin, petroleum bitumen, factis), fillers (trans-polynorbornene, carbons black (P 514, P 803), and natural chalk). As a result of the studies, it is established that with an increase in the content of polyisobutylenes from 5 to 20 phr a change in the physico-mechanical properties of rubber is observed (a decrease in tensile strength, hardness, and tear resistance), while the relative elongation at break and the dynamic properties of rubber increase. Moreover, with polyisobutylene content up to 15 phr, the physico-mechanical properties of rubber change within acceptable limits, but at 20 phr these properties deteriorate sharply. Vulcanisates containing polyisobutylenes P-30 and P-200 up to 15 phr exhibit smaller changes in physico-mechanical properties and mass after exposure to sea water. It has been determined that rubber containing 15 phr polyisobutylene P-200, due to its physico-mechanical, performance and dynamic properties, can be recommended for the manufacturing the products operating under exposure to sea water.

The influence of the structure of low molecular weight nitrogenous bases in heavy oil on the composition and aggregative stability of asphaltenes has been studied. The objects of investigation were asphaltenes of heavy oil from the Usinsk field, as well as asphaltenes of model petroleum systems with nitrogen content 1.0-3.0 wt%, obtained by mixing the original oil with quinoline and pyridine. IR spectroscopy and elemental analysis were used to determine the composition and structure of asphaltenes. The colloidal stability of asphaltenes was analysed by spectrophotometry. It is shown that the introduction of nitrogenous bases into heavy oil leads to a decrease in hydrogen content with an increase in the proportion of nitrogen, which points to the incorporation of pyridine and quinoline molecules into the supramolecular structure of asphaltenes. The main reason for the incorporation of nitrogenous bases into asphaltene aggregates is the p-stacking interactions of aromatic rings. The colloidal stability of asphaltenes, assessed as the time of sedimentation onset, is determined to increase by a factor of 1.5, with an increase in pyridine content, and the degree of sedimentation inhibition can reach 90 % with respect to asphaltenes in the original oil. On the contrary, the presence of quinoline in asphaltenes causes a several-fold decrease in the time of their aggregation onset, but it also promotes detention of a part of aggregates in the colloid state, which results in a decrease in the amount of precipitate in comparison with original oil.

The features of the behaviour of rare earth elements (REE) and strontium in hemihydrate and dihydrate processes of sulphuric acid processing of Khibiny apatite concentrate have been studied on the basis of investigation of the residues of aqueous leaching of phosphogypsum obtained under production conditions. It has been shown that the increased degree of REE ingress into phosphogypsum of the hemihydrate process, compared to phosphogypsum of the dihydrate process, is determined by the technological features of these processes: higher temperature and REE concentration in the liquid phase of the pulp of the hemihydrate process, compared to the liquid phase of the pulp of the dihydrate process. In contrast to existing ideas, it is theoretically justified and experimentally confirmed that a significant part of REE in phosphogypsum of the hemihydrate process is present in the form of rhabdophane. Rhabdophane was not found in phosphogypsum from the dihydrate process, and it is most likely that REE in phosphogypsum from the dihydrate process are isomorphically cocrystallised with gypsum. It has been established that strontium occurs partially in the form of celestine in phosphogypsum of both processes. It is shown for the first time that celestine, present in phosphogypsum of the dihydrate process, contains isomorphically cocrystallised REE. It has been suggested that isomorphically cocrystallised REE may be also present in celestine from phosphogypsum of the hemihydrate process. The influence of REE forms present in phosphogypsum on the possibility of its sulphuric acid leaching is discussed. The results obtained in the work are of high practical importance because sulphuric acid leaching is widely recommended for organising the industrial extraction of REE from phosphogypsum obtained during sulphuric acid processing of the Khibiny apatite concentrate.

The results of studies conducted at the Institute of Combustion Problems (Almaty, Kazakhstan) on the synthesis of nanocarbon materials and their application for environmental purposes are presented. The procedures have been developed for obtaining nanocarbon materials from rice husk and walnut shells (graphenes and activated carbon, respectively), the physicochemical properties of the synthesised materials and the possibility of their practical use are studied. Graphene investigation by infrared and Raman spectroscopy allowed us to analyse the surface functional groups and the structural features of the material composed of a mixture of amorphous carbon and graphene, the ratio between these components depending on synthesis method. With an increase in the amount of the alkaline agent, the content of graphene component in the structure of carbon material increases. The porous structure and morphology of carbonised materials from rice husk and walnut shells were characterised according to the data of scanning electron microscopy. Nanocarbon graphene structures and activated carbon synthesised from the waste plant materials have demonstrated good adsorption properties for sea water desalination and sorption of toxic gases.

The anthropogenic emission of greenhouse gases, mainly carbon dioxide (CO₂), is considered as one of the main causes of global climate change. The transport sector is one of the largest emitters of carbon dioxide (accounting for more than 20 % of all CO₂ emissions), therefore, reducing the carbon footprint of vehicles should be considered one of the main directions of technological decarbonisation. It is shown in the article that the CO₂ emissions of motor gasoline significantly depend on the component composition of commercial gasoline. Calculations of specific CO₂ emission from the combustion of high-octane components of motor gasoline, namely reformate and isomerisate, were carried out. It is shown that for reformate, the specific emission of CO₂ per 1 t of reformate and per unit energy released is higher by 6.0 and 13.4 %, respectively, than the values for isomerisate. It is shown that the main reason for large specific CO₂ emissions for reformate is the high content of aromatic hydrocarbons in it. Moreover, unlike for paraffinic hydrocarbons, the lower is the molecular weight of aromatic compounds, the higher are specific CO₂ emissions. The presented results can be used to implement the transition to the low-carbon model for the development of the transport sector by utilising more environmental-friendly kinds of fuel through modifying its composition. These approaches do not require changing the design of internal combustion engines or introducing new infrastructure, as in the case, for example, of using engines powered by pure hydrogen.

Steam and steam-air reforming of butanol allows obtaining synthesis gas that can be used as a feedstock in a number of chemical applications or as a fuel for solid oxide fuel cells. The efficiency of these reactions is largely determined by heat transfer. In the case of steam reforming of methane, which is an endothermic reaction, it is necessary to provide heat transfer from the reactor walls into the catalyst layer. During steam-air conversion, which is a thermoneutral or weakly exothermic reaction, local overheating occurs in the front layer, the thermal effect of which must be redistributed over the catalyst layer to compensate for the endothermic effect prevailing in the tail section. To increase heat transfer, structured catalysts based on heat-conducting substrates, namely metal meshes, are used in this work. Such catalysts are a complex composite material with a multi-level structure: structured metal substrate - structural oxide component - active oxide - nanoparticles of metals or alloys, which combines the functions of a heat exchanger, a flow distributor and the catalyst itself. This allows you to control heat and mass transfer, regulate gas-dynamic resistance in the reactor and optimise the amount of catalytic material. In this work, the results of the preparation and study of the physicochemical and catalytic properties of Pt, Rh, Pd, Ru, Ni-containing structured catalysts supported on a fechral (FeCrAl) mesh support are presented. The prepared structured catalysts were tested in the reactions of steam and autothermal conversion of n-butanol into synthesis gas. The highest activity in these reactions was shown by the rhodium structural catalyst. Short-term laboratory resource tests for 15 h did not reveal the presence of soot on the surface of the catalyst, and the composition of the reaction products was close to thermodynamic equilibrium. This catalyst can be recommended for use in reformers for steam and steam-air conversion of butanol-1 to produce synthesis gas.

The possibility of obtaining benzocaine succinamide under the conditions of mechanochemical reaction of succinic anhydride with benzocaine (a local anesthetic) is demonstrated. It has been established that mechanical treatment in a ball mill results in amorphisation of initial substances, promoting adsorption of succinic anhydride on the surface of drug crystals, which leads to the chemical interaction between initial components. An intensive development of solid-phase interaction was determined to proceed intensively during 10 days after the load was removed. The maximum transformation degree (~90 %) was detected for the mechanical treatment of an equimolar mixture of benzocaine and succinic anhydride, in the amount of 4 g, in a ball mill for ~2 h. With a decrease in the mixture mass or increase in the load applied, the maximum yield is achieved within a shorter time. The conversion degree was determined to decrease with an increase in the time of mechanical action in all cases. The detected feature can be related to the equilibrium amidation under the conditions of heating during the long-term action of the impact load.

High-temperature studies of the structure of a composite material with the composition La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ-Ce_0.8Sm_0.2O_2-δ (LSCF64-SDC) have been carried out, and the oxygen permeability of microtubular membranes based on it was investigated. The phase composition of LSCF64-SDC composite was analysed using in situ high-temperature X-ray diffraction. It has been determined that at 700 °C under vacuum conditions, a structural transition to the high-temperature cubic phase occurs in LSCF64 oxide. The dependence of the oxygen permeability of microtubular membranes based on LSCF64-SDC on the partial pressure of oxygen and temperature has been established. The effective activation energy of the oxygen transport process was calculated. The effect of the CO₂ atmosphere on the values of oxygen flows through the microtubular membranes based on LSCF64-SDC was studied.

Quantum chemical simulation of the adsorption of phenylethanol on a tetrahedral Au₂₀ cluster was carried out using the density functional theory, DFT/B3LYP/LANL2DZ. It has been shown that gold atoms located at the top of the cluster have the highest activity in the adsorption of alcohol. Possible reactions of phenylethanol on Au₂₀ cluster to form phenylacetaldehyde were studied. Based on the calculated thermodynamic and kinetic values, it is concluded that the transformation proceeds predominantly through the metal hydride mechanism.

The proportion of hard-to-recover oil reserves in the world and in Russia is constantly growing. The development of hard-to-recover reserves, including high-viscosity oil deposits, low-permeability reservoirs, and difficult production conditions, such as the Arctic, is becoming an increasingly important factor in maintaining high levels of oil production. For the effective development of hard-to-recover reserves, physicochemical and complex technologies for increasing oil recovery have been developed at the Institute of Petroleum Chemistry SB RAS on the principles of green chemistry, buffer self-regulating systems and the method of deep eutectic solvents (DESs) using the smart compositions of surfactants, coordinating solvents, and complex compounds. The compositions chemically evolve in the reservoir with the acquisition and long-term preservation of colloidal chemical properties that are optimal for oil displacement. Factors causing chemical evolution include thermobaric reservoir conditions, interaction with reservoir rock and reservoir fluids. The review presents the fundamental and applied aspects of the physicochemical and complex methods for increasing oil recovery, developed at the Institute of Petroleum Chemistry SB RAS, the results of laboratory studies, field tests and industrial use of technologies for increasing oil recovery from the oilfields with hard-to-recover reserves under natural development mode and thermal steam influence, including the deposits of high-viscosity oils. Technologies are environmentally friendly and technologically efficient. To implement the technologies, acid and alkaline oil-displacing compositions based on surfactants and buffer systems with adjustable viscosity and high oil-displacing ability have been developed. The results of laboratory studies of phase equilibria, physicochemical, acid-base and rheological properties in surfactant - DES systems containing polybasic acid, polyols, urea, aluminium and ammonium salts are presented. The developed compositions possess the following advantages: they are compatible with formation waters, low-freezing ((-20)-(-60) °С) or solid, have low interfacial tension at the boundary with oil, applicable in a wide temperature range (10-200 °C). The industrial use of these technologies will make it possible to extend the profitable operation of fields with hard-to-recover oil in a wide range of climatic conditions, including the Arctic.

Development and operation of wells at oil and gas fields are often accompanied by unexpected complications related to drilling mud loss and breakthrough of gas and fluids through reservoir fractures, which requires repair and insulation operations (RIO) to be performed with adequate quality. The ways to improve the efficiency of repair and insulation operations in oil and gas wells with the use of gel-forming plugging materials are considered in the work. The use of various hydrophilic and hydrophobic dispersed and fibrous fillers in hydrogels based on polyacrylamide and complex organic crosslinker is proposed in order to improve their rheological properties and increase the blocking ability. Such organic-inorganic composites show a variety of rheological properties, which makes it possible to select the necessary hydrogel compositions for certain RIO. The results of rheological (oscillation) and filtration studies, as well as field tests of the compositions, are presented. Chrysotile, carbon black, hydrophilic nanosilica, and mechanically activated wood flour, rice husk, hydrolysed lignin were used as dispersed fillers in oscillation studies. Polypropylene fibres, basalt fibres and carbon fibres were considered as fibre fillers. The values of elastic modulus (G') and viscosity modulus (G''), crossover points and linear viscoelastic regions for each composition were determined from the results of oscillation studies. An increase in the modulus of elasticity up to 48 % (G' = 53.3 Pa) was achieved with the addition of carbon black and up to 50 % (G' = 54.2 Pa) for the composition with chrysotile and carbon fibre, compared to the base hydrogel without fillers (G' = 36.1 Pa). The addition of hydrophilic nanosilica allowed an increase in the yield strength (crossover point) by more than 300 % (to 210.4 Pa). Filtration studies were performed on the ideal fracture model with different opening (50, 100, 650 mm) using natural core samples. It has been established that during water filtration the hydrogel with chrysotile and polypropylene fibre additives has a higher residual resistance factor (RRF = 167) in the fracture with 100 μm opening than the base hydrogel (RRF = 136) in the 50 μm fracture. When blocking a gas-saturated model of an ideal fracture, the maximum RRF was 2677. Field tests of the composition with dispersed and fibre fillers for elimination of catastrophic drilling mud circulation loss and RIO were successful.