Home – Home – Jornals – Chemistry for Sustainable Development 2024 number 1

On 21-25 November, 2022, Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences (Irkutsk), organized an All-Russian anniversary conference celebrating 65 years to the date of the Institute foundation and 105 years to the birth of its first director, Lev Vladimirovich Tauson, Full Member of the Russian Academy of Sciences. The results reported at the conference encompass a wide range of research fields in modern geochemistry, including isotope geochemistry of igneous, metamorphic, and sedimentary rocks in various geodynamic settings; chemistry of ore-magmatic systems and modern methods of mineral exploration; environmental geochemistry, geoecology, and paleoclimate; laboratory modeling and thermodynamic calculations of natural and production-related processes and materials; advanced analytical methods and information technologies for geosciences. The conference presentations pay tribute to Lev Tauson whose academic carrier, as well as all creative activity, had been closely related with the development of the Institute of Geochemistry. The preface paper provides a review of topics discussed at the conference concerning various geodynamic and geochemical problems, including sources of material, petrogenesis, and metallogeny.

Integrated geological data, petrogeochemical characteristics of magmatites of the Kurung complex (the Ket-Kap-Yuna igneous province of the Aldan Shield), and previously published isotopic data along with the results of geochronology and geochemistry research provide evidence for this complex evolving in the Late Cretaceous in a setting of riftogenesis (final phase) of continental margins. Similar to the Late Jurassic-Early Cretaceous polyformational volcano-plutonism of the Aldan Shield, the Late Cretaceous alkaline magmatism in the Ket-Kap-Yuna province is associated with the tectonomagmatic activation which manifested itself mainly as continental margin rifting associated with deep reorganization of the southwestern, southern and southeastern framing of the Siberian craton triggered by gravitational sliding of the lithospheric plates. Results of the petrogeochemical analysis of the studied magmatites revealed that the heterogeneous rock groups identified within this rock complex are not related to each other by fractional or other type of differentiation, thus suggesting their possible derivation as a result of fluid syntexis-type interaction between mantle-derived alkali-basite melt and felsic crustal melts. Alkali-basite parent melts are shown to have formed during partial melting of variably enriched mantle which is widely spread beneath the Aldan Shield and is varied in composition (from BSE enriched to nearly EM-I). Origination of such deep-seated melts (magma sources) was associated with the rifting processes (strike-slip tectonics) triggered by the setting of gravitational sliding of lithospheric plates. The formation of alkaline-salic magmas of the Kurung complex is associated with large-scale selective assimilation of crustal material by high-temperature fluidized mantle magmas during their ascent to the surface, possibly as a result of fluid syntexis of alkaline-basite mantle magmas and crustal smeltings formed under their influence.

We have first determined the petrogeochemical, Sm-Nd isotope, and U-Th-Pb geochronological (detrital-zircon LA-ICP-MS) characteristics of terrigenous rocks from a thick sequence in the south of the Sangilen block, which is part of the Central Asian Orogenic Belt (CAOB). The rocks are heterogeneous in facies composition: From west to east, there is a transition from graywacke sandstones with an admixture of pyroclastics to much more silicic lithoid arenites. Geochronological data on detrital zircons from the predominant graywacke sandstones mark the following intervals of concordant ages (Ma): 787-907, 1870-2236, 2613-2725, and 2900-2980. With regard to the oldest determined age (early Cambrian, 520 Ma) of the igneous rocks intruding these sandstones, the possible period of accumulation of terrigenous sequences in the south of the Sangilen block is estimated at 790-520 Ma. The obtained geochemical, Sm-Nd isotope, and U-Th-Pb geochronological data point to Neoproterozoic and early Precambrian island arc and continent-marginal complexes as probable provenances for the terrigenous deposits of the “southern band”. The relative proportions of rocks of these complexes in the deposits changed with distance from the sedimentary basin (from west to east, in modern coordinates): The portion of early Neoproterozoic juvenile rocks decreased, and the portion of early Precambrian metamorphic complexes increased. The Paleoproterozoic and Mezoarchean detrital zircons found in the terrigenous rocks of the Sangilen block could not originate from any known Precambrian complexes of the Tuva-Mongolian microcontinent. This gives grounds to regard other craton blocks of the CAOB as their sources.

Primary melt and fluid inclusions in quartz and dalyite of calcite-quartz carbonatitoids of the Murun massif have been studied. They contain CO₂, N₂, CH₄, C₂H₆, C₃H₈, H₂, and H₂S as well as sulfates and hydrocarbonates as solid daughter phases. The inclusion solutions contain HS- and chlorides. In addition, disordered carbon and bitumen are present. It is concluded that the magmatic fluid phase that was in equilibrium with quartz was characterized by a predominantly H₂O-CO₂-H₂S composition and a reduced state. This explains the appearance of sulfides at the magmatic stage of crystallization of calcite-quartz carbonatitoids of the Murun massif. We substantiate the hypothesis that the sulfates, hydrocarbons, and H₂ detected in the inclusions form at decreasing temperature as a result of shift of the redox equilibrium.

Multidirectional dynamics of changes in the chemical composition of the water of the only runoff of Lake Baikal, the Angara River, has been established. The cyclic-wave change in the interannual chemical composition of the Baikal water has been revealed, which indicates a long-term memory effect in the chemical time series of elements. Positive and negative temperature and chemical trends in the state of the water in the source of the Angara are observed, which are due to climate changes, the confinement of Baikal to the rift zone, and the composition of the enclosing rocks. It is shown that the current concentrations of monitored elements in the Angara source water depend also on their past concentrations but can change dramatically in the case of catastrophic environmental disturbances caused by natural and anthropogenic disasters (fires, drought, floods, earthquakes, etc.). The relationship between the elevated concentrations of uranium in the water and the seismic process in the Baikal area has been traced. The data obtained are based on the long-term (1950-2021) monitoring of the chemical composition of water in the Baikal ecosystem (Baikal, its tributaries, and Angara source).

Understanding the main events of platinum-group element (PGE) ore formation is impossible without analysis of the sources and behavior of major ore-forming components, namely, platinum, osmium, sulfur, and copper, which are important indicators of magmatic and hydrothermal processes. In contrast to the Re-Os isotope system, the radiogenic Pt-Os isotope system, as well as stable isotopes of Cu and S in PGE deposits, are still relatively understudied. Our comprehensive research is aimed at filling this gap. The paper presents data for the Guli massif of ultramafic and alkaline rocks and carbonatites in Polar Siberia and on the zonal Nizhny Tagil and Svetly Bor clinopyroxenite-dunite massifs in the Middle Urals, which include: (1) the contents of the highly siderophile elements (HSE) in whole rocks and platinum-group minerals (PGM), (2) the Re-Os and Pt-Os isotope systematics of chromitite, Os-Ir alloys, and Ru-Os sulfides, (3) the sulfur isotope composition in Ru-Os and Ir-Rh sulfides in primary and secondary PGM assemblages, and (4) the copper isotope composition in Pt-Fe minerals from chromitites and placers. The research was performed using scanning electron microscopy, electron probe microanalysis, and high-precision isotope-geochemical analysis. The high-precision Re-Os and Pt-Os isotope data show that the HSE contents in chromitites and PGM of the Guli massif were controlled by the composition of the mantle source that evolved with near-chondritic time-integrated Re/Os and Pt/Os ratios, which are also typical of the sources of most komatiites and abyssal peridotites. The δ⁶⁵Cu values of the studied samples of ferroan platinum and isoferroplatinum are identical within the analytical uncertainty and are close to 0‰, which is typical of high-temperature Cu-containing minerals. The sulfur isotope compositions of the Ir-Rh sulfides of the kashinite-bowieite series and of the Ru-Os sulfides of the laurite-erlichmanite series in the primary PGM assemblages indicate that the source of sulfur has a chondritic isotope composition, which is in agreement with the osmium isotope composition of the Ru-Os sulfides and Os-Ir alloys. The heavy sulfur isotope composition (δ³⁴S = 5.6 ± 1.5‰) of As-containing erlichmanite is consistent with its secondary origin. The new data on the isotope compositions of osmium, copper, and sulfur can be used as new important parameters that characterize the sources of PGE mineralization.

Here we report results of microforms’ studies of native gold and its alloys in igneous rocks, modified to varying degrees by secondary processes. We discuss the composition and occurrence of both the deep-seated magmatic gold-bearing alloys and the products of their transformation under conditions of the upper Earth’s crust. Gold-bearing Kamchatka adakites and ankaramites, Ildeus massif mafic-ultramafic intrusions and adakites from the Stanovoy fold system as well as dacites from the Bolivian Andes were formed during melting of either the suprasubduction mantle wedge or the subducted oceanic crust. In depleted peridotites from the Avachinsky Volcano in Kamchatka as well as suprasubduction ophiolites from Polar Urals, Eastern Sayan and the Western Mediterranean Betic-Rifean belt, the gold-bearing mantle was hybridized by subduction-related melts and high-temperature fluids. Volcanic rocks associated with the Lesser Khingan Fe-Mn deposits and Zolotaya Gora Au deposit in Southern Urals as well as Taragai ultramafic rocks in the South Khingan Range display subduction-related geochemical characteristics. Gold-bearing trachytes in the Virginian Appalachians (USA) represent felsic differentiates of mafic intraplate magmas. We propose that one of the principal forms of gold transport into the upper crustal environments is represented by Cu-Ag-Au alloys, which precipitated from mantle-derived silicate melt enriched in chalcophile and siderophile elements. Such Cu-Ag-Au alloy-rich magmatic rocks can either constitute primary sources of precious metals in the mantle-crust system or serve as geochemical precursors to the formation of native gold assemblages in epithermal and mesothermal ore deposits. Presence of magmatic gold particles in subduction-related igneous rocks and mantle restites hybridized by subduction-derived melts and high-temperature fluids suggest the existence of gold-rich horizons in the Earth’s mantle at depths comparable to typical depths of generation of primary convergent zone and some within-plate magmas.

The Ugakhan gold ore deposit is located within the Lena gold ore province, the largest one in Russia. It belongs to the group of deposits of the Sukhoi Log genetic type. We present results of petrological, mineralogical, and isotope-geochemical study of gold mineralization at the deposit. A scheme of the sequence of mineral formation at the deposit has been developed, which includes five stages: (1) the early (syndiagenetic) stage, when framboid pyrite I enriched in Au, Ni, Co, and As formed; 2) the stage of catagenesis of ore-bearing sediments, with recrystallization of early pyrite I and crystallization of pyrite II, also with elevated Au, Ni, Co, and As contents; (3) the stage of progressive metamorphism, with the formation of ore pyrrhotite from a water-CO₂ fluid with a high content of H₂S; (4) the ore formation stage, marked by an assemblage of pyrite III, galena, sphalerite, chalcopyrite, and native gold at the deposit, which was synchronous with regressive metamorphism in the region; (5) crystallization of post-ore euhedral coarse-grained pyrite IV. The geochemical and isotope (δ³⁴S and Pb-Pb) data rule out the input of mineral-forming components from an additional (external) source during the hydrothermal-metasomatic transformation of ore-bearing rocks. The δ³⁴S values in the early morphotypes of pyrite in the deposit ores vary from +5.7 to +9.1‰ and are close to the δ³⁴S values of the barren rocks of the Buzhuikhta Formation (+4.2 to +16.4‰). The Pb-Pb isotope characteristics and regularities of variations in Pb isotope composition established for gold mineralization indicate a predominant inflow of lead from Neoproterozoic metasedimentary strata. The mineral and geochemical specifics of the Ugakhan deposit are consistent with the concept of the metamorphic origin of gold deposits of the Sukhoi Log type, which confirms that the rocks of the Buzhuikhta Formation are promising for new gold ore objects.

The paper presents results of research into the conditions of formation of ores in the poorly studied Algama ore cluster (Bodorono deposit and Dyvok ore occurrence) located at the junction of the Aldan Shield and the Stanovoi area. We have established that Bi and Se minerals (bismuthinite, lillianite, native bismuth, tellurobismuthite, tetradymite, hedleyite, pilsenite, and laitakarite) are present in the ores of the Bodorono deposit. Two successive productive stages of mineral formation have been distinguished: Au-polymetallic and Au-Bi-Te. The corresponding minerals are products of the evolution of a hydrothermal system, during which a gradual decrease in fluid temperature (from 300 to 145 °C) and salinity (from 5 to 1.9 wt.% NaCl equiv.) took place. The fineness of native gold gradually increases from early (~840‰) to late (~940‰) stages and changes in passing from simple sulfides to sulfosalts. The evolution of the ore system is accompanied by a change in the composition of the vapor phase of fluid inclusions from CH₄-CO₂ to CO₂ with an impurity of N₂ and CH₄. The results of ⁴⁰Ar/³⁹Ar dating of pre-ore metasomatites point to ore-forming processes at the Bodorono deposit ca. 150 ± 1.8 Ma. Analysis of the isotopic composition of lead in galena shows the leading role of the ancient crustal source of ore matter. The calculated isotopic composition of oxygen (δ¹⁸O_H2O) in ore-bearing quartz varies from 1.0 to 7.3‰, which corresponds to an aqueous fluid of a mixed source. The Dyvok ore occurrence differs from the Bodorono deposit in the mineral composition of ores and the physicochemical parameters of ore formation. Four mineral stages have been established within the ore occurrence: gold-arsenopyrite-pyrite-quartz, pyrite-chalcopyrite-sphalerite, quartz-boulangerite, and telluride. The telluride stage is represented by hessite, altaite, volynskite, merenskyite, melonite, and rucklidgeite. Gold-bearing mineralization formed from a fluid of medium salinity (0.9-9.2 wt.% NaCl equiv.) with a predominance of CO₂ and an impurity of CH₄ in the vapor phase at moderate temperatures (310-360 °C). The calculated values of δ³⁴S and δ¹⁸O varied from 2.2 to 3.0‰ and from 0.6 to 12.0‰, respectively. The ⁴⁰Ar/³⁹Ar age of gold mineralization is 124.0 ± 1.5 Ma, which corresponds to the stage of tectonomagmatic activity in the Aldan Shield.

High-precision satellite laser ranging (SLR) is actively used all over the world to solve a variety of tasks, primarily in geodesy and navigation. However, the disadvantage of laser systems is the dependence of the effectiveness of their use on weather conditions, in particular, on the presence of clouds. However, in separate experiments conducted at the JSC “Precision Systems and Instruments" (JSC “PSI"), it was possible to receive laser pulses on board a spacecraft in cloudy conditions. The purpose of the work is to evaluate the possibility of functioning of the metrological laser system (MLS) developed at JSC “PSI" in the presence of certain types and forms of clouds that allow the reception and determination of the parameters of laser pulses. Mathematical models of the atmosphere for a laser radiation wavelength of 0.532 microns have been developed, including optical characteristics of the crystalline medium for aggregate structures of ice particles. Calculations of the transfer of optical radiation of subnanosecond laser pulses from ground stations to high-orbit and low-orbit spacecrafts in the presence of upper- and middle-level crystalline clouds have been performed. The amplitude-time characteristics of optical signals on board the spacecrafts are calculated. It is shown that the principles of one-sided SLR can be implemented in the presence of cirrus, cirrus-layered, and cirrus-cumulus clouds in the sky, as well as altostratus clouds with established limitations on the optical thickness. The results confirm the possibility of increasing the technological performance of high-precision SLR systems, in particular, MLS, since the repeatability of the cloud forms under study over the territory of the Russian Federation is about 20%.

For a 3-dimensional dynamical system considered as a model of a gene network with nonlinear degradation of its components, the uniqueness of an equilibrium point is proved. Using approaches of qualitative theory of ordinary differential equations, we find conditions of existence of a cycle of this system and describe an invariant domain which contains all such cycles in the phase portrait. Numerical experiments with trajectories of this system are conducted.

The main focus of this paper is an analysis of the semilocal convergence (S.C.) of a three-step Newton-type scheme (TSNTS) used for finding the solution of nonlinear operators in Banach spaces (B.S.). A novel S.C. analysis of the TSNTS is introduced, which is based on the assumption that a generalized Lipschitz condition (G.L.C.) is satisfied by the first derivative of the operator. The findings contribute to the theoretical understanding of TSNTS in B.S. and have practical implications in various applications, such as integral equations further validating our results.

A three-dimensional (3D) matching operator is proposed for a fourth-order accurate solution of a Dirichlet problem of Laplace's equation in a rectangular parallelepiped. The operator is constructed based on homogeneous, orthogonal-harmonic polynomials in three variables, and employs a cubic grid difference solution of the problem for the approximate solution inbetween the grid nodes. The difference solution on the nodes used by the interpolation operator is calculated by a novel formula, developed on the basis of the discrete Fourier transform. This formula can be applied on the required nodes directly, without requiring the solution of the whole system of difference equations. The fourth-order accuracy of the constructed numerical tools is demonstrated further through a numerical example.

The results of modeling the propagation of seismoacoustic waves based on the numerical solution of a direct dynamic problem for a porous medium are considered. The propagation of seismic waves in a porous medium saturated with fluid in the absence of energy loss is described by a system of differential equations of the first order in the Cartesian coordinate system. The initial system is written as a hyperbolic system in terms of the velocities of the elastic host medium, the velocity of the saturating fluid, the components of the stress tensor, and the pressure of the fluid. For the numerical solution of the problem posed, the method of complexing the integral Laguerre transform in time with a finite-difference approximation in spatial coordinates is used. The solution algorithm used makes it possible to efficiently carry out calculations when modeling in a complexly constructed porous medium and to investigate the wave effects that arise in such media.

A study of the influence of unbalancing the processor load in parallelization of solutions of 3D boundary value problems on quasi-structured parallelepiped grids is carried out. Estimates of the influence of the unbalance on the time of solving the problems depending on the number of processors and the number of grid nodes used are given. The results of numerical experiments confirm the theoretical conclusions.

The paper deals with a numerical solution of the wave equation. The solution algorithm uses optimal parameters which are obtained by using Laguerre transform in time for the wave equation. Additional parameters are introduced into a difference scheme of 2nd-order approximation for the equation. The optimal values of these parameters are obtained by minimizing the error of a difference approximation of the Helmholtz equation. Applying the inverse Laguerre transform in the equation for harmonics, a differential-difference wave equation with the optimal parameters is obtained. This equation is difference in the spatial variables and differential in time. An iterative algorithm for solving the differential-difference wave equation with the optimal parameters is proposed. 2-dimensional and 1-dimensional equations are considered. The results of numerical calculations of the differential-difference equations are presented. It is shown that the difference schemes with the optimal parameters give an increase in the accuracy of solving the equations.

In this paper, we provide a new a posteriori error analysis for a linear finite element approximation of a parabolic integro-differential optimal control problem. The state and co-state are approximated by piecewise linear functions, while the control variable is discretized by a variational discretization method. We first define elliptic reconstructions of numerical solutions and then discuss a posteriori error estimates for all variables.

A problem of variational data assimilation for a sea thermodynamics model is considered, with the aim to reconstruct sea surface heat fluxes taking into account the covariance matrices of input data errors. The sensitivity of some solution functionals to input data in this problem of variational assimilation is studied, and the results of numerical experiments for a model of dynamics of the Baltic Sea are presented.

An inverse problem of reconstructing a coefficient in the differential equation of a model of development for a homogeneous biological population of organisms structured by age is considered. The model takes into account the impact of migration flows on population size changes. Conditions are established to ensure the uniqueness of the solution of the inverse problem. A brief overview of algorithms for the numerical solution of the inverse problem is provided.

A three-dimensional model for a burner is established, and effects of gas nozzle structural parameters on the combustion performance of the burner are studied. With a change in parameters, the reverse flow zone in the furnace changes obviously. The interaction and symmetry of the four reverse zones directly affect the flame stability. The change in the maximum and average temperatures in the furnace is not the main reason for the increase in NO_x emissions at the furnace outlet (M_NO). Most probably, the increase in M_NO is caused by the characteristics of the high-temperature area. In ten cases studied, the NO_x emissions are all lower than 30 mg/m³ and even lower than 10 mg/m³ in some cases (under normal conditions), which indicates that the ultra-low nitrogen emission of the boiler can be achieved by reasonably modifying the nozzle structure

Propylene oxide (C₃H₆O) is an intermediate product of oxidation of heavy hydrocarbons and can be used as an additive to conventional fuels to reduce soot emissions. New experimental data on the oxidation of C₃H₆O at low temperatures were obtained using an isothermal jet-stirred reactor. Experiments were carried out at temperatures of 600-1300 K and a pressure of 1 atm, and the residence time of the gas mixture in the reaction vessel was 1 s. Five detailed chemical kinetic mechanisms taken from the literature were tested. A mechanism that has the best predictive ability at low temperatures was identified. The mechanisms were also tested against experimental data on the structure of C₃H₆O flames. It has been found that at the moment there is no model that can correctly describe the combustion and oxidation of C₃H₆O at both low and high temperatures.

An economical method for numerical simulation of natural excitation of gas vibrations in low-emission combustors of gas turbine units has been developed and tested. The method is based on the use of the SAS SST k-ω turbulence model and the turbulent combustion model with a modified equation for a variable degree of combustion completion. To model the natural excitation of gas vibrations, a factor associated with gas pressure pulsations is introduced into the source term of this equation. Isolation of one of the modes of gas vibrations prone to natural excitation is carried out using a resonant filter operating in each cell of the computational domain. The results of the computational study obtained using the proposed method make it possible to study the influence of design measures and operating parameters of natural vibrations and to approach more rationally the choice of measures to suppress them.

The effect of heat loss on the possibility of implementing the most effective gas-phase combustion mode of a single boron particle in air at various initial temperatures and pressures of the oxidizing medium is analyzed analytically, taking into account the possible entry of the particle into the air environment, the temperature of which is lower than the melting point of boron, after its ignition and reaching a stationary gas-phase mode combustion. A method for calculating the maximum initial air temperature below which cooling and extinguishing of a burning boron particle occurs has been developed, and the boundaries of the regions of its gas-phase combustion and extinguishing have been determined. It has been established that when a single boron particle burning in a gas-phase mode enters air with a temperature below the melting point, the main factor determining the mechanism of its combustion is the air temperature, depending on which either the continuation of combustion of the particle in the gas-phase mode or its cooling takes place and changing the combustion mode to heterogeneous.

The total and radiant heat fluxes from a flame onto the surface of a solid fuel (polymethylmethacrylate) in the combustion zone for horizontal flame spread over the fuel surface were first quantitatively measured using two water-cooled miniature sensors with dimensions of 2.3 × 2.3 mm mounted inside the plate. A water cooling design for 2 × 2 × 0.5 mm sensors (greenTEG AG) has been developed that makes it possible to place them directly in the combustion zone. Radiant heat flux was measured by a sensor with a protective window made of ZnSe, and the total heat flux was measured by a similar sensor without protective window. The conductive heat flux determined using sensors was compared with that calculated from polymethylmethacrylate flame temperature measurements with thin thermocouples. The maximum radiant and total heat fluxes from the flame to the surface of polymethyl methacrylate measured using thermal sensors were 30-35 and 70-75 kW/m², respectively.

Regimes of detonation burning of a two-phase mixture consisting of TS-1 aviation kerosene and air in a radial vortex chamber 500 mm in diameter with exhaustion toward the center and geometry variations at the combustor entrance and exit are obtained and studied. Air is injected into the combustor through a vortex injector, and kerosene purged with air was injected through oppositely directed channels. Optical registration of the process was performed through transparent windows in the combustor by a high-speed camera with a frequency of 420000 frames per second. The flow pattern observed in the combustor with a free exit and an expanding nozzle is continuous spin detonation with one detonation wave rotating with a velocity of 1.68-2.17 km/s close to the Chapman-Jouguet detonation velocity or pulsed detonation with radial waves with a frequency of 0.14-0.26 kHz. Mounting of radial partitions yields pulsed detonation or combustion. In continuous spin detonation, the air flow rate is 3.6-11.7 kg/s, the kerosene flow rate is 0.2-0.77 kg/s, and the equivalence ratio varies from 0.63 to 2.5.

A superfine microcrystalline powder of bis-(triaminoguanidinium)-5,5'-azotetrazolate (TAGzT) is prepared by the high-energy ball milling method. The microstructure, elemental composition, thermal decomposition mechanism, and sensitivity characteristics of fine TAGzT are studied by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), thermal gravimetric and mass spectrometry, and sensitivity tests. The results show that fine TAGzT consists of irregular granules with a rough surface and contains only C and H elements. TAGzT begins to decompose at about 199 °C, with the thermal decomposition products being mainly CH₄, NH₃, and H₂O. The sensitivity test shows that fine TAGzT has good stability. As calculated by the EXPLO-5 software, fine TAGzT has better energy performance than HMX. Composite modified double base propellant (CMDB) samples containing fine TAGzT are designed and prepared. The microstructure, elemental distribution, thermal decomposition mechanism, and sensitivity characteristics of CMDB propellant samples are studied by SEM, EDS, XPS, DSC, and mechanical sensitivity tests. The results show that there are tiny bulges and cracks on the sample surface, and the mass ratio of the components is consistent before and after preparation. With an increase in the fine TAGzT content in the propellant, the thermal decomposition peak temperature moves backward, while E_K increases first and then decreases. The H₅₀ value of the CMDB propellant decreases with an increase in the fine TAGzT content. The CMDB propellants are calculated using the CproPEP software, where fine TAGzT is added to the propellant formulation to have higher values of I_sp and C* than those of HMX and lower values of T_c and M_c. By introducing fine TAGzT into the CMDB propellant, higher energy and better safety can be obtained

This study is aimed at investigating the mechanism by which a reactive material enhances the energy output of a composite charge consisting of an inner explosive, an intermediate non-detonating layer, and an outer explosive, which are widely used in tunable ammunition. Explosion experiments are conducted in two initiation modes. Using reactive Al/rubber significantly increases the fireball growth, shock wave velocity, and shock wave overpressure of the composite charge compared to using inert LiF/rubber. For simultaneous initiation, the increase is more obvious owing to the continuous exothermic reaction of the reactive layer. A composite charge with 40% (vol.) Al shows the highest difference in peak overpressure under the two initiation modes: 41.4%. A charge with 60% (vol.) Al ensures even lower shock wave and fireball velocities and peak overpressure than those of the 40% (vol.) Al charge, indicating that the excessive reactive Al content in the non-detonating layer inhibits the blast of the composite charge.

The relationship between the critical detonation thickness in transverse wedges made of plasticized TATB and the acoustic rigidity of the adjacent material and the speed of sound in it was determined by streak photography. The wedge-shaped charge was initiated over the entire lateral surface of the detonation wave propagating in a steady mode.

The process of detonation propagation in a charge made of a plasticized explosive composition based on TATB in the form of a hollow cylinder with a steel shell inside is studied when normal detonation is initiated along a line on the outer surface of the charge. In experiments, the shape of the detonation wave (DW) front at certain points in time was determined using the X-ray method. Using electric contact sensors, the speed of propagation of the DW front along the outer surface of the charge was measured. The original setup of the experiments made it possible to study the propagation of detonation at angles greater than 180 °C from the initiation line. It is shown that in the initiation plane the front velocity of the diverging DW is ≈7.3 km/s. In the region of the “shadow” of the initiation point, the speed of the front of the diverging DW decreases depending on the distance traveled both along the outer surface of the charge - up to ≈6 km/s, and along the inner - up to ≈5.6 km/s. At the same time, near the steel shell in the region of rotation angles of the DW front from approximately 150 to 210 °C, a zone of unreacted TATB was recorded, which may indicate the disruption of detonation and its transformation into a shock wave. A numerical simulation of the process was carried out using the SURF detonation kinetics implemented in the MIMOSA technique. The calculation results are in good agreement with experimental data both at the early stage of the detonation initiation process and in the region of the “shadow” of the initiation point, where the velocity of the DW front decreases.

A semi-empirical equation of state for bismuth has been constructed taking into account five solid phases, liquid, evaporation, and thermal ionization. The results of model calculations are in satisfactory agreement with data from static and dynamic experiments in the pressure range from atmospheric to ≈1 TPa and temperatures from room to ≈10⁵ K.

Periclase (MgO) is one of the important materials that make up the mantles of the terrestrial planets. In this regard, its properties at high temperatures and pressures reflect the nature of the planetary interior. Numerical modeling of shock wave loading of MgO taking into account the polymorphic phase transition in a pressure range of 325 ÷ 400 GPa was carried out using a thermodynamic equilibrium model. The parameters of the consistent equation of state for the high and low pressure phases of periclase (MgO I and MgO II) are determined. The thermodynamic parameters of these phases were modeled. Shock adiabats of single and double compression were constructed in the range 1 ÷ 1000 GPa, the values of heat capacity along the normal isobar, entropy as a function of temperature, and temperature along the shock adiabat were calculated. The modeling results were verified based on the results of experiments and calculations of other authors.

The paper is a summаry of experimental studies of water droplet breakup in the flow behind the shock wave in the range of gas flow velocities 40 ≤ U ≤ 175 m/s. A change between two different mechanisms of stalling breakup of the droplet occurs in this range of velocities, with domination of the inertia force in the case of droplet deformation and viscous friction force in the case of boundary layer shedding. The analysis of the change in the breakup mechanisms is based on a vast pool of observations and quantitative data on droplet dynamics and delays of its breakup obtained by a high-speed method of visualization with a stroboscopic laser source of light. A physical model of the process is constructed on the basis of experimental data and results of the parametric analysis, and criteria of the change in stalling mechanisms of droplet breakup are derived.

Gas chromatography with mass spectrometric detection (GC-MS) was used to study the composition of bromides obtained upon selective cleavage (chemolysis) of the C-O bond of ether/ester bridges under the action of BBr₃ in oil components from ten oil and natural bitumen samples. It is shown that most of the samples under study demonstrate the absence of mono- and dibromides of alkanes, alkylcyclohexanes, pregnanes and steranes, cheilanthanes and hopanes in the products of chemolysis. Monobromides of n-alkanes have been identified only in the products of chemolysis of oil components isolated from maltha of the Ashalchinskoye oilfield and the products of its biodegradation under laboratory conditions. In total, the identified products of selective cleavage of ether/ester bridges include mono- and dibromides of alkylbenzenes: mainly (С₁₃-С₂₂)-alkyltrimethylbenzenes, (С₁-С₇)-naphthalenes, phenanthrene, dibenzothiophene and their homologues. Monobromides of C₆-biphenyl, C₄-tetralin, dibromides of (C₂-C₆)-benzothiophenes, (C₂-C₅)-biphenyls, C₁-tetralin, fluorene, and C₂-fluorene have been also identified. Tribromides of (С₂-С₄)-naphthalenes, С₂-phenanthrene, and (С₁-С₂)-fluorenes have been identified in a limited number of samples. In chemolysis products, dibromides occur more rarely than monobromides, while tribromides are much less common than dibromides. The results obtained indicate that the above-mentioned compounds are partially present in oils as structural fragments connected with other fragments of the oil components through one or much less often through two or three ether/ester bridges. The list of structural fragments linked via ether/ester bridges, their composition and relative content differ in oil components of different oil and natural bitumen samples. Ethyl esters of aliphatic acids from C₁₂ to C₃₂, with a clear predominance of even acids and a maximum corresponding to C₁₆ and C₁₈, have been identified in the products of chemolysis of almost all samples.

The influence of pine bark pre-activation conditions - 1) in a planetary mill AGO-2, 2) with water vapor under the conditions of explosive autohydrolysis (EAH) - on the sorption activity of resulting sorbents with respect to methylene blue and gelatin was studied. It is shown that explosive autohydrolysis is a more efficient method to activate pine bark, and under certain conditions it leads to an increase in the sorption of methylene blue and gelatin at least by a factor of 1.8 and 3.8, respectively, compared with the sorbent from non-activated bark. The activating treatment of pine bark in a planetary mill makes it possible to increase the sorption of methylene blue and gelatin not more than by a factor of 1.3 and 1.2, respectively. A mathematical model is obtained that describes the effect of explosive autohydrolysis conditions (water vapour pressure and duration of pine bark treatment) on the sorption properties of the resulting sorbents. Optimal conditions providing the maximal sorption of methylene blue by the obtained sorbent are determined: temperature 155 °C; water vapour pressure 2.62 MPa; processing time 58.6 s. The sorption properties of the sorbent predicted by the mathematical model have been confirmed experimentally. Sorbents from pine bark, activated by explosive autohydrolysis, surpass the industrial enterosorbent Polifepan from hydrolytic lignin in their ability to absorb methylene blue and gelatin, which indicates the prospects for their use as enterosorbents in medicine and veterinary medicine. The results of the conducted research allow us to consider pine bark as an alternative raw material that can replace hydrolytic lignin in the production of effective enterosorbents.

The physicochemical properties and catalytic activity of regenerated spent aluminium-cobalt-molybdenum hydrotreatment catalyst have been investigated under cracking conditions in the model systems n-dodecane - toluene and decalin - toluene - n-hexane. A series of experiments to study the catalytic activity of the sample was carried out using a flow-type laboratory installation within the temperature range 430-470 °C, nitrogen pressure 1.6 MPa, liquid hourly space velocity 0.5-3.0 h^-1. The directions of transformation were determined for paraffin and naphthenic hydrocarbons by means of gas chromatography - mass spectrometry. Paraffin hydrocarbons enter into cracking, isomerisation and compaction reactions. Naphthenic hydrocarbons are transformed into the products of isomerisation, dehydrogenation and compaction. Predominant dehydrogenation of decalin with the formation of naphthalene and hydrogen is observed in the system under investigation. A positive role of hydrogen in thermodestructive processing of heavy oil residues is observed due to the hydrogenation of nonlinear olefin hydrocarbons and aromatic hydrocarbon intermediates, which decreases the rate of coke formation. The corresponding reaction rate constants were calculated, and the results were analysed. Conclusions are drawn about the prospects of introducing a regenerated spent hydrotreatment catalyst into the procedure of thermodestructive processing of heavy oil residues.

The chemical composition and reactivity of the native cellulose of cotton grass ( Eriophorum scheuchzeri ) in the production of cellulose nitroesters based on this type of raw material are investigated to assess the suitability of the native cellulose fibres of the seed pods ( Eriophorum scheuchzeri ) for the production of cellulose nitroesters on this basis. It is shown that the mass fraction of cellulose in the studied plant raw materials reaches 79 %. The degree of cellulose polymerization is 1510 units. The possibility of obtaining cellulose nitroesters in a practical yield of 64 % on the basis of this type of plant raw materials without preliminary delignifying treatment has been revealed. The chemical composition of the obtained cellulose nitroesters has been established. Their technical compliance with colloxylin H is shown. Based on the conducted studies, an intermediate conclusion is made about the potential suitability of this type of plant raw materials for the production of cellulose nitroesters.

The phase compositions and particle morphology of nanostructured Co-Pt system, obtained by the reduction of aqueous solutions of precursors with hydrazine hydrate, have been studied (for the first time in the Pt-rich region) by X-ray diffraction analysis (XRD), transmission electron microscopy (coupled with electron diffraction (ED)), thermogravimetry, small-angle X-ray scattering analysis (SAXS) and elemental analysis of the samples. As determined by XRD, with Co content less than approximately 60 at%, the only phase is determined: the face-centred cubic ( fcc ) phase of the solid solution of Co in Pt, with the upper limit of Co solubility in Pt equal to 18±1 at%. For Co content in the solid solution higher than its solubility limit during the synthesis, diffraction-undetectable phase (phases) is also formed in addition to the fcc solid solution phase. The presence of such phases was confirmed by the results of SAXS, and their metal nature, rather than oxide-hydroxide one, was confirmed by XRD, ED, and thermal analysis.

The catalytic reaction of n-heptane (n-C₇H₁₆) oxidation with molecular oxygen has been studied. Various compositions of the polymer catalyst Mn-P4VP/MBAA (where Mn-P4VP is manganese-immobilised poly-4-vinylpyridine and MBAA is N,N′-methylene-bis-acrylamide) containing 2-5 wt% Mn were prepared and tested. The concentration of manganese in the catalyst based on immobilized metal-polymer complexes is within the range of 2-5 wt% Mn. The oxidation reaction was carried out at a ratio of components n-C₇H₁₆/O₂/polymer catalyst with Mn = 1 : 3.38 : 0.003 and time 6 h within the temperature range 303-383 K. The data on the yield of the major products of n-heptane oxidation are presented, taking into account the initial components, catalyst composition, temperature and the time of oxygen contact with the reacting components. It has been established that during the oxidation of _n-C₇H₁₆ (303-383 K), the yield of alcohols is higher than the yield of other oxidation products. The oxidative conversion of _n-heptane increases from 45 to 75 mol% with an increase in temperature in the range of 303-383 K. For the multistage oxidation of n-heptane with oxygen, a kinetic model was selected and considered. On the basis of this model, the reaction rate constants were calculated in the range of 303-383 K considering the degree of heptane conversion. The activation energy of n-heptane oxidation was estimated, taking into account the method of choosing the most plausible parameter and experimental data on n-heptane convection.

Technological parameters for reforming process are chosen and optimised through an increase in temperature at the reactor inlet and increased selection of benzene-containing fraction during catalysate fractionation, which made it possible to obtain the fraction (100-200 °C), a heavy reformate of the required quality in terms of octane number - 99.5/89.5 (determined by the research/motor method, respectively), and use it as a high-octane component in the production of AI-100-K5 gasoline. Relying on the data of mathematical modelling, requirements to minimise energy consumption, and the standards for the content of aromatic hydrocarbons in commercial motor gasoline, it was proposed to increase the feedstock temperature by 1 °C at the inlet to the reformer unit reactors. A formalised scheme of hydrocarbon transformations in the reforming feedstock that occurs with an increase in process temperature is proposed, which explains the qualitative and quantitative changes in the fractional composition of the catalysate. It has been established that an increase in the extraction of benzene-containing fraction makes it possible to reduce the yield of light reformate, increase the octane number, and reduce the mass fraction of benzene to 1.5 wt% in heavy reformate. Using the Aspen PIMS programme software package, the optimal composition of AI-100-K5 gasoline was modelled, including light straight-run naphtha isomerisate, C₄ hydrocarbon fraction raffinate, high-octane gasoline component (alkylate), methyl tert -butyl ether and heavy reformate obtained under the conditions of optimized scheme. The quality of the manufactured pilot batch (MPB) of fuel fully meets the requirements of TR TS 013/2011, STO 44905015-005-2017 and the standards established for the performance properties of AI-100-K5 gasoline, determined by qualification methods and engine-bench tests. The manufactured MPB of motor gasoline AI-100-K5 exhibits improved operational and environmental characteristics, since sulphur content is reduced to 8.0 mg/kg, benzene content to 0.38 vol%, and the volume fraction of aromatic and olefin hydrocarbons to 28.6 and 4.2 vol%, respectively. As a result of motor-bench tests, it is established that AI-100-K5 gasoline has a reduced tendency to form deposits on intake valves and soot in the engine combustion chamber.

One of the main problems in oil production is the formation of stable oil-water emulsions that cause corrosion of pipelines, malfunction of pumping equipment, and poisoning of catalysts at refineries. The features of the viscosity-temperature behaviour of high-viscosity resinous crude oil from the Russkoye field (Yamal-Nenets autonomous district) and its 30 wt% emulsion after exposure to electromagnetic and low-frequency acoustic fields are investigated. Electromagnetic treatment of crude oil leads to a decrease in the phase transition temperature and the yield strength coefficient. Low-frequency acoustic processing of the emulsion is accompanied by a decrease in the effective viscosity and the yield strength coefficient. After a complex wave action, the viscosity-temperature characteristics of crude oil continue to fall, and the stability of the formed emulsions decreases due to the intense coalescence of water-phase droplets. It is shown that the amount of released asphaltenes in oil-containing systems decreases after wave treatment. On the contrary, after a complex impact, their content in crude oil increases, while in the emulsion it continues to decrease. This is likely to occur due to the release of hydrocarbons occluded in the asphaltene structure into the liquid oil phase.