Home – Home – Jornals – Combustion, Explosion and Shock Waves 2022 number 4

The impact of suspended particles in the urban air on the health of different groups of the population of Tomsk, Russia, is studied. It is shown that women are generally most susceptible to the adverse effects of aerosol air pollution and extreme (high summer and low winter) air temperatures. Women at age of 65-74 are the most vulnerable to the environment hazards. The age-and-sex matched analysis of mortality allows us to determined groups of population (age, causes of death) the most sensitive to high aerosol concentrations and extreme air temperatures: women at age of 65-74, cancer of the digestive system, breast cancer, and acute myocardial infarction; women at age 34-50, undetermined causes; women at age 75-87, breast-pang; men at age 53-65, other forms of coronary artery disease; men at age 78+, male reproductive organ cancer. It is shown that the general mortality of the population is mainly due factors not studied in this work. However, the risk of the negative impact of air pollution is significant for the selected groups of population in the region under study.

The results of surface ozone monitoring in the atmosphere of Moscow in 2020 and 2021 under lockdown associated with the COVID-19 pandemic are presented. These two years significantly differed in meteorological conditions and the level of anthropogenic impact on the environment. A relatively low for metropolis concentrations of surface O₃ were observed in Moscow in 2020. The annual average value was 28 mg/m³, and the annual maximum was 185 mg/m³. That was due to a combination of relatively cool weather with low levels of pollutants in the air. Several intense heat waves were observed in the metropolis under conditions of a blocking anticyclone during summer 2021, daytime temperatures rose to 35 °C. Along with higher air pollution, that resulted in unusually high O₃ concentrations. The annual average value was 48 mg/m³, and the annual maximum was 482 mg/m³.

The problem of electromagnetic scattering on ice crystals of cirrus clouds was solved for 94 GHz radar (wavelength 3189 mm) and lidar (wavelength 0.355 mm) with the refractive indices of ice - 1.7864 + 0.0032 × i and 1.3249 + 0 × i respectively. The scattering matrices were calculated within the physical optics approximation and the discrete dipole approximation for the case of randomly oriented particles. The particle sizes varied from 4 to 1000 mm. It was possible to correctly calculate the ratio of the radar and lidar signals in the backscattering direction, called the radar-lidar ratio. The ratio was obtained for the wide particle size distribution for typical shapes of cirrus cloud ice crystals. It is shown that this ratio can be used to estimate the size of ice crystals in cirrus clouds.

The operational features of the new RAD-MSU(BSRN) robotic radiation complex, mounted at the MSU Meteorological Observatory in 2021, are discussed. Though the RAD-MSU(BSRN) complex is not a part of BSRN (Baseline Surface Radiation Network), it is equipped with a full set of instruments recommended by the BSRN, including for measurements of all components of net radiation, UVA radiation, erythemal UV radiation, and sunshine duration. The specially developed software for visualization and processing of measurement data, including evaluation of data quality criteria, is described. The main features of variability of the components of net radiation and UV radiation in 2021 are analyzed.

The results of numerical simulation of the optical radiation focusing by Fresnel zone plates (ZP) with the wavelength-scale (mesowavelength) dimensions and a two-layer profile of phase ridges are presented. We show that the dimensions and intensity of the focusing area are sensitive to the type of ZP design. By changing the phase step shape (height and width of plate faces) it is possible to significantly improve the characteristics of the light field in the focusing region due to smoothing the wave phase profile after passing through individual ZP layers. A comparison is made with the case of a conventional binary ZP.

The paper estimates the gross and net primary production based on long-term series of complex measurements of carbon dioxide concentrations in the near-water atmosphere and surface and bottom water, as well as fluxes in the “water - atmosphere” system for the most characteristic seasonal cycles of the life of the Baikal plankton. The calculations were carried out according to the scheme similar to the diel method. With regard to the conditions of the coastal zone, the analysis of methodological issues was carried out, neglect of which can lead to a significant uncertainty in these characteristics. It is shown that in this scheme, having only CO₂ concentration measurement data, it is not possible to correctly estimate the net primary production. For periods of open water, its calculation was carried out using the daily average CO₂ flux. The results of the assessment of bioproductivity, carried out in detail for individual series of measurements in different periods, quite adequately show the main features and are consistent with the data of long-term observations.

The macrokinetic laws of combustion and the kinetics of thermal decomposition of energetic condensed compositions containing high-enthalpy polynitrogen compounds based on the system of furazan, furoxan, and azepine rings and poly-2-methyl-5-vinyltetrazole as an active binder. The linear rates of high-temperature transformations (combustion) of compositions with different ratios of components were determined in the nitrogen pressure range 1 ÷ 6 MPa. It was found that the burning rate of compositions of polycyclic compounds and poly-2-methyl-5-vinyltetrazole exceeds the burning rate of individual components, with the synergistic effect increasing with decreasing nitrogen pressure in the system. Kinetic studies of heat release during thermal decomposition of energetic compositions in the temperature range 50 ÷ 350 °С under isothermal and nonisothermal conditions have shown that in pressed compositions, reactants interact, leading to a significant increase in the rate thermal decomposition of the mixture relative to the rate of decomposition of individual components. The data obtained indicate that one of the reasons for an increase in the burning rate upon mixing of components may be a change in the leading combustion reactions as a result of the chemical interaction of components of the binary composition.

Combustion of high-energy condensed systems may include the formation of an intermediate structure (skeleton layer, which significantly affects the combustion process. The influence of binder solidification on the formation of such a structure is studied experimentally. It is demonstrated that the laws of the skeleton layer formation during binder solidification depend to a large extent on the polymer structure. A specific role of the substance acting as a binder is determined. The basic features of modeling phenomena in the surface layer with and without the skeleton layer are presented. The possibility of predicting a number of characteristics of the combustion process is demonstrated.

Distribution of plutonium and americium compounds in the combustion products of radioactive graphite in water vapor or air is analyzed. The study is carried out via thermodynamic analysis using the TERRA software package in a temperature range of 400÷3200 K. It is revealed that all carbon in water vapor passes into gas at temperatures above 900 K, and its transition temperature in air is 1000 K. Condensed plutonium compounds transform into vapor compounds in water vapor at temperatures above 1800 K and in air at 1700 K. Condensed americium compounds begin transforming into a vapor state at temperatures above 2000 K, and their transition temperature in air is 2200 K.

Powders of various metals and boron are widely used in mixed fuel compositions to increase the combustion temperature and specific impulse of rocket engines. The article presents the results of an experimental study of the oxidation and ignition in air of ultrafine aluminum powders Alex, amorphous boron and microsized aluminum powders μAl, aluminum borides AlB₂ and AlB₁₂. Metal and boron powders were heated and ignited by a cw CO₂ laser in the heat flux density range 65 ÷ 190 W/cm². Based on thermal analysis data, it was found that the powder reactivity parameters are arranged in the following sequence (in descending order of activity): Alex ® B ® AlB₁₂ ® AlB₂ ® μAl. During the oxidation of amorphous boron and aluminum dodecaboride AlB₁₂, the total specific heat release and the rate of mass change have maximum values. Alex, boron and AlB₁₂ powders ignite more easily in air under the action of an external radiant source. Power exponent n as a function of the ignition delay time t_ign on the heat flux density t_ign ( q ) = Aq ^{- n} for μAl powders, AlB₂ and AlB₁₂ are approximately the same and equal to »2.0, for ultrafine Alex and boron powders it is lower and amounts to n = 1.5 and 1.0, respectively.

Effect of furan (C₄H₄O) and tetrahydrofuran (C₄H₈O) additives in a mixture of ethylene (C₂H₄) with argon on soot formation during pyrolysis behind reflected shock waves in a pressure range p ₅ = 2.1 ÷ 4.4 atm and a temperature range T ₅ = 1 600 ÷ 2 580 K is studied. Temperature dependences for the volume fraction of the condensed phase and the sizes of forming carbon nanoparticles in the studied mixtures are obtained by laser extinction and laser-induced incandescence. It is revealed that adding these furans increases the volume fraction of soot and expands the temperature range of its formation. The effect of furan turns out to be more pronounced than that of tetrahydrofuran. It is shown by the kinetic modeling of ethylene pyrolysis processes with the selected additives that alternative pathways for the production of C₃H₃ propargyl are formed in the presence of C₄H₄O and C₄H₈O, which is the reason why soot formation improves.

The fraction of methane in gas hydrates is approximately 12 wt. %. Theoretically, the temperature of combustion of such a composition is rather low. Nevertheless, the measurements show that an appropriate organization of the process may ensure a much higher flame temperature. For this purpose, it is necessary to separate the regions of dissociation and combustion (i.e., eliminate water heating). On the other hand, for combustion to be stable, some part of the combustion heat should be returned to the hydrate region to maintain the dissociation rate at a needed level. Stability of methane hydrate combustion is naturally determined by the ratio of heat release and heat transfer. The present paper described experiments on methane combustion above a layer of a dissociating gas hydrate, and a simple mathematical model is proposed for estimating diffusion combustion stability. A comparison of the modeling results with experimental data allows one to determine the water vapor concentration and to find the thermal balance of hydrate combustion.

Combustion of ethylene and kerosene in flows with Mach numbers M ≤ 2 is numerically studied. Flow throttling with the use of a side jet of compressed air is provided for igniting the fuel injected through an axial injector and for supporting its combustion. The Reynolds-averaged Navier - Stokes equations closed with the k-ε turbulence model are solved. Fuel combustion is modeled by one reaction. The possibility of formation of a transonic flow is considered. The gas-dynamic structure of the flow in the channel in the case of kerosene combustion is investigated for the Mach number M = 1.7 and stagnation temperatures of 1 400 and 1 500 K. The computations are performed for various values of the limiter of turbulent kinetic energy generation.

The characteristics of combustion of liquid hydrocarbons in the presence of a mixture of superheated water vapor with a diluent gas in a vaporizing burner are studied by an example of diesel fuel. Carbon dioxide is used as a diluent gas. The experiments reveal regimes of injection of superheated water vapor or carbon dioxide, as well as their mixture in various proportions, that ensure similar profiles of the mean flame temperature, thermal power, and air-to-fuel ratio. It is demonstrated that fuel burning in the presence of superheated water vapor, carbon dioxide, and their mixture allows reaching low concentrations of CO and NO _x in combustion products. In the case of CO₂ injection, these values are at the boundary of admissible concentrations for class 3 in accordance with the EN:267 norms. In the case of injection of only superheated water vapor, the nitrogen oxide emissions in flue gases are smaller than those in the case of carbon dioxide injection: reduction of NO _x emissions can reach 15 %.

A mathematical model based on macrokinetics is proposed for the numerical simulation of the auto-ignition period of fuel in a local volume of a hydrogen diesel engine with high pressure fuel injection equipment. Hydrogen auto-ignition in homogeneous chemical reactors for operating conditions of real hydrogen diesel engine at the moment of the start of hydrogen gas injection was simulated using a chosen detailed kinetic mechanism of hydrogen oxidation and a special software package. The results of these simulations for reactors of constant volume and constant pressures were used to derive an equation for the macrokinetics of hydrogen oxidation at high pressures. Using this equation, various operation modes of a hydrogen diesel engine with heating of air and hydrogen were investigated by numerical methods. Ways to reduce the induction period and increase the reliability of the engine are discussed.

Results of geochemical investigation of drainage waters discharging from the mining objects (dumps, quarries, tailings) of the Orlovskoe tantalum deposit (Transbaikal Territory) are presented. It is determined that the drainage waters from the dumps of overburden rocks and from blast holes are acid and weakly acid, and highly mineralized (TDS up to 4232 mg/L). With respect to the chemical composition, these waters are mainly of sulphate type, with anomalously high concentrations of aluminium, fluorine, chalco- and siderophilic elements. The waters of the tailing storage facility are neutral and weakly alkaline, with increased tungsten and arsenic concentrations. Thermodynamic calculations of the major forms of element migration in drainage waters show that simple cationic forms dominate for most metals, while the second prevailing forms are sulphate and fluoride complexes. The average concentrations of Mn, Al, Be, Zn, Fe, Li, Со, Ni, Cu, W, F^- and SO₄^2- are determined to be substantially higher than the maximum permissible concentrations for water objects for fishery, household, drinking and amenity water usage, which is connected both with the composition of the ores and host rocks of this deposit, and with technogenic activities.

In this study, the conditions for the precipitation of aluminium hydroxide from sodium aluminate solutions obtained from the alkaline solution of raw alunite ore by hydrogen peroxide, an eco-friendly reagent, are studied. Factors influencing the precipitation by H₂O₂ and aluminium hydroxide from diluted aluminate solutions (concentrations of hydrogen peroxide and alkali, volume ratios of hydrogen peroxide and aluminate solution, temperature, time, caustic modulus) are investigated and found under optimal conditions (initial concentration of hydrogen peroxide >15 %; temperature 20-40 °C, V_H2O2/V_sol = (5-20) : 20 mL, alkali concentration 42.33 g/L (according to Na₂O)) precipitation of ~95 % of aluminium in aluminate solution is achieved. The recovery of alkali (sodium hydroxide) after the precipitation of aluminium hydroxide by H₂O₂, its return to the leaching of alunite has been studied, and several difficulties have been eliminated in the precipitation of aluminium hydroxide by other methods. The characteristics of the obtained samples are confirmed by means of XRD, SEM/EDS analysis.

Comparative analysis of the macro and trace element composition of fruit, leaves and stems of the plants was carried out with respect to the content of mineral nutrition elements in the soils in the natural population of the Altai subspecies of blue honeysuckle (Lonicera caerulea subsp. altaica) in the local zone where disjunctive geological structures are concentrated in the valley of the Kyzyl-Yaryk river (the Altai Mountains, the North Chuya Ridge). Substantial variations of the total content of macro and trace elements Ca, Al, K, Na, Sr, P, Mn, Ba, B, Zn, Cu, Cr and Ni, the mobile forms of Ca, Sr, Fe, Mn, Cu, Cr, Ni, Co, Na in the soils and soil acidity (pH 4.5-6.7) were revealed at the regions differing from each other in the volume activity of radon emission field (262-1162 Bq/m³). Micropopulations of L. caerulea subsp. altaica at these regions differed from each other in the level of accumulation of Сu, K, P, Na, Mo, Cr, P, Sr, Si in plant organs, and in the physiologically essential ratios Cu/Zn, Fe/Mn and K/Ca. An increase in the Cu/Zn ratio in plant organs had a significant effect on a decrease in fruit size, number of seeds in fruit, their germination capacity, and an increase in the seed germination power. The seed germination power is also in significant positive correlation with the level of Ca, Mg, Cr, Cu, Sr, Pb accumulation in leaves and stems, and with the Fe/Cu ratio. The content of K in fruit is in significant negative correlation with seed germination power.

The problem of utilization of sludge from the storage facilities of the Baikal Pulp and Paper Mill (BPPM) for the purpose of improving the environmental situation in the Baikal region is considered. Geographical and seismic characteristics of the territory where this object of environmental danger is located are described. The factors threatening Lake Baikal are highlighted. Qualitative and quantitative characteristics of sludge-lignin contained in sludge storage facilities are presented. During the recent years, all the numerous attempts to utilize sludge-lignin invariably ended in failure. Transportation of waste to other temporary settling tanks located at a distance from Lake Baikal also would not solve the problem and can only worsen the current situation due to the large volume of accumulated waste and the permanent flow of rain and snowmelt water into the settling tanks. A retrospective review of the technical, technological and organizational measures taken by the administrative and engineering personnel of the BPPM and aimed at economically affordable and environmentally friendly disposal of sludge waste from sedimentation tanks was carried out. The analysis of patent, scientific and technical data bases made it possible to select a number of documents concerning the reactivity of lignins in the sulphate production of cellulose. The information is found that the dry sludge-lignin product of BPPM had been in demand by oil and gas exploration enterprises throughout Siberia for several years (1980-90s) as a cheap substitute for water-soluble cellulose esters, starch, xanthan resins and other components for washing liquids during the construction of deep oil and gas wells. Ways of utilization of the sludge-lignin component of the BPPM sedimentation tanks are proposed.

The effect of the mixtures of ethers and alcohols on the performance characteristics of motor petrol is investigated. The objects of investigation are industrially available domestic oxygenates: methyl tert -butyl ether (MTBE) and isobutyl alcohol (IBA). Investigation of the effect of the ratio of these oxygenates in the two-component mixture on the change in antiknock activity of petrol revealed a synergistic effect in the octane number within the range of the concentrations of MTBE (20 to 80 wt. %) and IBA (80 to 20 wt. %). Involvement of this two-component mixture in petrol provides an increase in the octane number. The optimal ratio of oxygenates is determined (MTBE/IBA = 50 : 50 wt. %), which provides, along with the manifestation of the synergistic effect in octane number (an increase by 7.9 units), a more uniform distribution of octane numbers over fractions and stability of performance characteristics during transportation and storage of commercial fuel. Resulting from the discovered synergism of oxygenates MTBE and IBA, a new additive to motor petrol is developed. In order to enhance and expand the range of action of the new additive based on the two-component mixture of MTBE and IBA, a formulation involving monomethylaniline (MMA) and anti-corrosion additive DCI-11 is developed. At the same time, the amount of MMA involved in motor petrol compounding did not exceed the sensitivity of the method. In comparison with the additive based on the two-component mixture, the use of the additive with an extended range of action made it possible to enhance the anti-knock characteristics (at the level of 1 octane unit, depending on the ratio) and anticorrosive properties (degree of corrosion 0 points) of petrol.

The effect of natural surfactants (SA) on the efficiency of the polymer additive against the formation of deposits in high-paraffin oil with increased content of resin-asphaltene components is investigated. It is demonstrated that the addition of the polymer to oil, either individually or with natural SA, causes a decrease in the amount of the formed deposits. It is determined that the maximal inhibiting ability is exhibited by the composition containing the polymer and 0.03 wt. % naphthenic acids (SA). Natural SA, either alone or together with the polymer, when added to oil, cause a decrease in the size of associates of paraffin hydrocarbons and their aggregates in the oily fraction of the oil deposits under investigation.

As an alternative to mercury release by cementation on metallic aluminum, for the purpose of improving the purity of commercial selenium, we investigated the processes of selective sorption of mercury ions from the technological solutions of selenous acid onto styrene-divinylbenzene Lewatit MP 68 resin. The isotherms of mercury ion sorption are obtained, the main quantitative parameters and limiting stages of the process are assessed. It is established that for a low degree of resin filling with the sorbate (with the equilibrium concentration of mercury ions in solution ≤0.4 mmol/dm³) and for the sorbent - sorbate type interaction, the distribution coefficient decreases initially, and then increases while the sorption ability increases and the structures of sorbate - sorbate type are formed. The degree of mercury extraction from solution (β) is inversely proportional to the equilibrium concentration of mercury ions in the solution ( С_eq) and is described by the linear equation: β = -133.5 С_eq + 99.81. Experimental data processing shows the simultaneous occurrence of the stages of external (film) and internal (gel) diffusion, which is evidence in favour of mixed diffusion sorption mode. The rate constants of external diffusion are approximately three times larger than the rate constants of internal diffusion. It is shown that the kinetic equations of pseudo-first and pseudo-second order models provide satisfactory description of experimental data, and that the difference between determination coefficients is not large ( R_i² > 0.98). The values of thermodynamic functions of mercury sorption within the temperature range 298-333 K were determined: -Δ G = 2.35-2.99 kJ/mol, Δ H = 3.1 kJ/mol, Δ S = 18 J/(mol•K). The practical significance of the revealed sorption parameter (dynamic exchange capacity of Lewatit MP resin is 68-269 g/dm³, specific volume of solution for resin saturation in the dynamic mode is 3800, element content in saturated resin is, %: Hg ~26.0, Se <1.0) is due to their involvement in designing the industrial installation.

A new method of purification of rough sphene concentrate from phosphorus impurities has been developed, based on its treatment with low-concentrated solutions of orthophosphoric or sulphuric acids in the presence of sulphocationite. It is shown that this method provides effective purification of sphene concentrate and makes it possible to increase the efficiency of the technology through significant reduction of the consumption of acids, elimination of the formation of liquid waste, and due to the possibility of using aluminium, which is formed during the decomposition of nepheline contained in the initial concentrate.

A new cyclopropane-containing optically transparent copolymer has been obtained by radical copolymerization of 4-(2-carboxycyclopropyl)styrene (CCPS) with acrylonitrile (AN), and its characterization was carried out. The structural peculiarities of the obtained polymer and the basic regularities of the studied process are investigated, the useful properties of the obtained compound are revealed, and the possible areas of its practical use are considered. It is established by means of turbidimetric analysis that the obtained polymer products are true copolymers, and not a mixture of two homopolymers. It is shown that copolymerization reactions proceed with opening of the double bond of the vinyl group in CCPS and AN. Copolymerization constants are measured ( r ₁ = 0.7 and r₂ = 0.15), Q-e Alfrey-Price parameters ( Q ₁ = 0.267, е₁ = -0.30) and microstructures of the copolymer are determined. During radical copolymerization, CCPS shows higher activity in comparison with AN. It is revealed from the microstructural parameters of the copolymer of CCPS with AN that the minimal blocking occurs in the range of M₁ / M₂ ~ (50 : 50)-(25 : 75), where M₁, M₂ are the fractions of CCPS and AN, respectively, mol. %. It is revealed that the radical copolymerization of CCPS with AN in the bulk allows obtaining the polymer with high purity in comparison with copolymerization of the monomers in the benzene solution. For obtaining the copolymer with the highest light transmission, comonomer ratio CCPS/AN should be 75 : 25 mol. %. The physical-mechanical, thermophysical, optical properties of the obtained copolymer are determined. In comparison with polystyrene and the copolymer of styrene with AN, the synthesized new copolymer possesses higher heat resistance, tensile strength and water absorption. It is established that the synthesized copolymer samples are characterized by good light transmission (87 %) and optical transparency ( n_D²⁰ = 1.5898). The copolymer of CCPS with AN possesses higher light transmission and refraction index than the copolymer of styrene with AN. The change rate of the light transmission index of copolymer of CCPS with AN depending on the composition of the synthesized polymer is investigated.

Coke formation process is studied by the example of SARA fractions - saturated (S) and aromatic (A) hydrocarbons, resins (R) and asphaltenes (A) - naphthenic and methane crude oils by means of thermogravimetry. The studied oil samples are characterized as heavy, high-sulphur, high-resin and contain large amounts of asphaltenes. They differ from each other in the content of resins, asphaltenes, sulphur, and in the yields of fractions with the initial boiling point (IBP) 360 ^оC. Thermogravimetric analysis was carried out heating the samples from 25 to 650 C at a rate of 10 C/min in argon. It is demonstrated that the yield of coke-like condensation products (coke) depends on the composition and structure of SARA fractions. During thermal analysis, the yield of coke is lower from the fractions of saturated and aromatic hydrocarbons and resins of naphthenic oil than from similar fractions of methane oil. The amount of solid products formed during thermal analysis of asphaltenes from naphthenic oil is larger than for asphaltenes of methane oil. Experimental and calculation data on coke yield from thermal analysis of model mixtures are presented. It is determined that coke formation during thermal analysis of model mixtures is not a direct function of the additive contribution from each of the components of the mixture.

Application of activated carbon (AC) obtained from cotton wastes (bolls, stems, and roots) for phenol adsorption from water, or wastewater dephenolization, is presented. The kinetics of phenol adsorption by carbon adsorbents were studied using UV/Vis spectrophotometer. The porosity of the formed ACs ranged from 1.952 to 2.339 cm³/g, the volume of macropores was from 1.79 to 2.09 cm³/g, while the commercial sample BAU-A showed 1.920 and 1.320 cm³/g, respectively. The highest phenol adsorption rate, 32.49-52.80 mg/(g•min), was observed for contact time up to 5 min on carbon adsorbents obtained from cotton waste. The adsorption equilibrium was achieved within 5 min after the contact, which is shorter than the analogous commercial adsorbents (7-12 min). Sufficiently high phenol adsorption activity of AC from cotton stems, roots and bolls is revealed. Therefore, the use of AC from cotton wastes as adsorbents for the treatment of industrial wastewater to remove organic and other impurities can be recommended for environmental remediation applications.

An urgent direction of the fuel and energy industry is the development of methods for vegetable oil and hydrocarbon co-processing in order to produce low-freezing and environmentally friendly components for diesel fuel. Zeolites of different structures and modifications are becoming increasingly popular as catalysts for these processes. Processing of the straight-run diesel fuel and a mixture of diesel fuel with 10 vol. % sunflower oil has been carried out over a zeolite catalyst of ZSM-5 type at a pressure of 0.35 MPa, feed rate 0.5 h^-1 and two different temperature points: 375 and 475 °C. Regularities of temperature effect and the influence of sunflower oil involvement into processing over zeolite catalyst on the composition and properties of the products are determined. These regularities are shown to depend on process temperature. It is established that the products of diesel fuel co-processing with sunflower oil over the zeolite catalyst at 375 °C correspond in their low-temperature characteristics to the Arctic grade of commercial diesel fuel, and at 475 °C - to the winder grade of commercial diesel fuel. It is demonstrated that the products of processing over the zeolite catalyst are promising components of low-freezing fuel. The results provide evidence that co-processing of diesel fraction and sunflower oil over the zeolite catalyst is promising for obtaining low-freezing components of engine fuel. The involvement of sunflower oil will expand the feedstock pool for fuel production.

Microcystin-producing culture of benthic cyanobacterium Tychonema sp. BBK16 isolated from biofilm fouling of the coastal zone of Lake Baikal is described for the first time. The pink colour of the trichomes and the developed keritomy of the cells indicate belonging to the genus Tychonema . Investigation of the morphology and the fragment of the 16S RNA gene showed the uniqueness of this type of cyanobacteria, the closest relative of the new species being the rheophilic cyanobacterium Tychonema sp. K27 from the karstwater stream. At the phylogenetic tree, together they form a separate clade of benthic attached forms. It is determined that the Baikal strain of Tychonema sp. BBK16 produces microcystin LR and does not synthesize anatoxin, which distinguishes it from the previously described species. This ability was revealed in vitro on media with Baikal bottled water and with wastewater from sewage treatment plant of Vydrino settlement. The addition of purified wastewater to the medium enhances the metabolism of cyanobacteria and results in an increase in the concentration of microcystin LR to 320 μg/g of dry weight. Assimilation of the additional amount of biogenic and organic substances by cyanobacteria has a stimulating effect on their metabolism. Analyzing the emergence of cyanobacteria of Tychonema genus in Lake Baikal, we assume that these bacteria undergo mass development in places of excess intake of nutrients, in particular those of organic origin.

Nanostructured composite material is obtained on the basis of multiwall carbon nanotubes filled with the products of thermal decomposition of cobalt complexes with disodium salt of ethylenediaminetetraacetic acid (Trilon B) - CoH₂Y. The performed characterization of the composite shows that the content of cobalt in it is consistent with that assigned during the synthesis, and sodium chloride obtained as a by-product is almost completely removed by washing. The consistent results of cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance measurements reveal a noticeable increase in the electrical capacity of the carbon matrix in the region of low scanning rates with the introduction of a filler (up to 1.8 times at a rate of 10 mV/s), which is associated with the occurrence of relatively inertial electrode Red-Ox processes like CoO ↔ CoO _х (OH) _у ↔ Со₂О₃ ↔ Со₃О₄ under these conditions. At high potential scanning rates, the introduction of small amounts of filler (less than 5%) has practically no effect on charge accumulation. With an increase in filler content, a symbate decrease in the capacity is observed, which is likely associated with an increasing blocking of the nanotube surface and a decrease in the capacity due to the formation of an electric double layer, while the Red-Ox reactions with the participation of the filler do not occur under these conditions due to relatively low rates. The results of impedance and galvanostatic measurements are consistent with this model.

The results of the local fires reconstruction based on the stratigraphic analysis of the peat deposit in the right-bank part of the Dubches River valley (middle taiga of the Yenisei Siberia) in the Holocene are presented. The object of research was the raised pine-shrub-sphagnum bog with a well-developed tree layer with Scots pine ( Pinus sylvestris L.). The deposit thickness was 4.15 m, its age was interpreted by 11 radiocarbon dates. The bottom peat layer age was 11802 ± 52 ¹⁴C years ago. In a peat core at depths of 3.25, 3.15, 2.90, 2.65 m, traces of fires were found in the form of pyrogenic layers. Reconstruction of the fire dynamics was carried out according to the method of counting macroscopic particles of charcoal “Charcoal”. The time, periodicity and intensity of fires on dry areas surrounding the bog have been established. Four periods were identified in the dynamics of local fires: about 12000-10000, 8250-7250, 6300-4000, 2400 cal. a BP (calibrated age before present). The reliable peaks of charcoal inflow occurred on the following dates: 11600, 11150, 10500, 7800, 5900, 5450, 4600, 1900, 1200 and 250 cal. a BP. It is noted that the highest fire activity was observed in the early Holocene, as evidenced by the increased content of macrocharcoals in peat. The main cause of the fires was probably the abnormally dry spring-summer seasons due to the dry and warm climate. The bog was traversed by fire during: 7790, 7030, 5610 and 4890 cal. a BP. The pyrogenic destruction of peat was minimal, which indicated a weak or medium intensity of the peat fire. Fires in the bog contributed to the activation of the forest formation process. In the late Holocene, the effect of fires on the bog ceased and forest phytocenoses were replaced by heavily watered ridge-hollow complexes.

The studies were carried out in forest peat soils of swampy river valleys of the eastern macroslope of the Kuznetsk Alatau. The content of macro- and microelements in the layer of modern soils (0-30 cm) varies greatly (Cv 42-88 %). The weighted average amount (taking into account the thickness of soil horizons and peat areas) within the orographic profile of 1087-573 m a. s. l. is: Fe₈₆₂₃ > Al₇₂₉₅ > Mn₃₃₅ > Sr₂₃₀ > Zn_37.8 > Cr_15.4 > Cu_13.2 > Ni_9.9 > Pb_4.6 > Co_3.4 > Cd_0.21, mg/kg. The methods of multidimensional statistical analysis have been used to structure peat soils according to the content of ash elements into three clusters corresponding to altitudinal gradient - 1087, 832-622, 573 m a. s. l. Zn and Fe have the greatest discriminating ability (82.6 %). A smaller share of the difference is provided by Cu, Ni (17.4 %). The topographic series of river valley peat soils are determined by the hydrogeochemical zonality of groundwater, as well as the removal of elements by lateral migration flows. For the first time, the boundaries of the vertical altitudinal zonality of peat soils are statistically were proved by the content of mineral elements and the geochemical composition of the selected ecotopic series (clusters) of soils is characterized. Only Pb and Cd accumulate in the soils of the autonomous landscape (highlands). In comparison with it, in the cluster of soils of the middle highlands, the amount of most ash elements increases by an average of 2 times. In the low mountains, the intensity of accumulation weakens somewhat. In the soil profile, the radial geochemical migration of iron as a characteristic element of swamps is more strongly positively correlated with the ash content of the peat substrate, strontium - with the soil pH, Cu and Mn - with fulvic acids. In the current period, no technogenic degradation of peat soils of the eastern macroslope of the Kuznetsk Alatau has been detected. The ecological and geochemical features of mountain peat soils are consistent with the characteristics of the natural biogeochemical provinces on the south of Central Siberia, within which they develop.

The results of external impacts on forest ecosystems, regardless of their origin, are expressed in a certain degree of degradation of the forest ecosystem and, as a rule, involve the identification of damage. The paper shows that before the impact, the cost of stands can be represented as the sum of ecosystem (ecological and resource) functions: C = СCi, where Ci is the cost of the i-th function of the n considered. The calculation is performed relative to a certain function, the cost of which is known. As such a function, the tax rate of payment for wood is used. It is also possible to calculate the relative market price of wood. The final values of the value of ecosystem functions, at the same time, will differ in proportion to the ratio of tax and market prices. After exposure, the cost of stands is determined by adjusting the cost of each ecosystem function. The difference between before and after exposure determines the amount of damage. In accordance with the intended purpose, as well as due to the difference in forest inventory indicators of the stands, estimates of the significance of ecosystem functions may radically differ. This means that the distribution of the shares of significance for each stand is individual. The sequence of identifying the cost of stand and further damage is demonstrated by the example of a section of pine-larch forest destroyed by fire on the territory of the Lake Uchum resort. It was found that before the fire, the cost of stand was 156 700 rubles/ha, after the fire it decreased to 27819 rubles/ha; damage was determined in the amount of 128881 rubles/ha.

The study focuses on the thermal analysis and flash pyrolysis of bark of Siberian larch ( Larix sibirica Ledeb.) and Scots pine ( Pinus sylvestris L.). Using thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC), a number of patterns of thermal decomposition of bark were established. The fourth derivatives of the DTG contours revealed differences in the “fractionality” of mass loss during heating of the bark samples. The thermal decomposition kinetics of bark was investigated using the Ozawa - Flynn - Wall isoconversion method. The obtained dependence of the activation energy ( E _a) on the conversion degree was used to calculate the thermodynamic parameters (Δ H , Δ G and Δ S ) of thermal decomposition. The mean values of E _a, Δ H , Δ G and Δ S were 206.7, 201.1, 248.7 kJ/mol and -78.0 J/(mol×K) for larch bark (LB) and 235.3, 229.7, 310.6 kJ/mol and -129.4 J/(mol×K) for pine bark (PB). The composition of mono-, sesqui-, diterpenes and oxygen-containing hydrocarbons of bark was determined by headspace GC/MS analysis. 37 and 41 volatile organic compounds were identified for LB and PB, respectively. The thermal stability of LB and PB was characterized using recalcitrant indices calculated from TG and DSC data. Integral values of exothermic effects of thermo-oxidative degradation were 15.1 kJ/g for LB and 15.9 kJ/g for PB. 55 flash pyrolysis products were identified, which accounted for 77.6 % of the total peak area for LB and 89.7 % for PB.

Attracting new species and varieties of ornamental plants is an urgent task of greening and landscape construction. The purpose of the study was to generalize the experience and investigate dynamics of the development of vegetative renewal of the Siberian phlox ( Phlox sibirica L.) in crops in the south of Central Siberia. The objectives of the study were to study the dynamics of development of the vegetative renewal of the Siberian phlox, and to determine the area of tufts formed by the spreading material during the growing season in the years of observation. According to the method of B. A. Dospekhov, in the Khakass Botanical Garden, by the method of organized repetitions, pieces of young rhizomes of a plant with one above-ground shoot were planted in 3 terms with two options (with shelter and without shelter). In the process of observation, at the beginning of the growing season, the number of shoots and the area of vegetative renewal were recorded for three years (2006-2008). It was established that: an increase in the area of turfs in the 1st year of vegetation occurred by 2.0-5.0 times, in the 2nd year - by 1.5-3.3 times, in the 3rd year - by 1.5-4.0 times. The obtained research results are reliable at the 5 % significance level. Over 3 years of vegetation, the increase in the area of turfs in the variants with the initial shelter occurred by 27.5-50.0 times, without shelter - by 50.0-128.0 times. The most active vegetative renewal occurred in plants planted at the earliest time (in early April), where the maximum value of turfs with an area of 1.1 ± 0.02 m² was obtained in the 3rd year of plant vegetation. On average, for the 1st year of vegetation in the variant with shelter, sods with an area of 0.05 m² were formed, and in the variant without shelter - 0.03 m². During the 2nd year of vegetation, in the variant with shelter, sods with an area of 0.33 m² were formed, and in the variant without shelter, 0.27 m². During the 3rd year of vegetation in the variant with shelter, sods with an area of 0.57 m² were formed, and in the variant without shelter - 0.6 m². In the arid conditions of the south of Central Siberia, for the purposes of greening and landscape construction, it is promising to use the Siberian phlox, which forms a good vegetative renewal and does not require systematic watering.

The Kayander larch ( Larix cajanderi Mayr) is the most important forest forming tree species of Chukotka, located on the northeastern border of its range. In the course of field studies in August 2021, the altitude limits of the larch distribution in the Chuvansky Ridge system, in the basin of the Ozernoe Gorlo River. In the estuary part of the valley of the Ozernoe Gorlo River has a significant array of larch forest. Between the Lednikovoe Lake and the mouth of the Ozernoe Gorlo River, at the height of the riverbed 290-350 m, the parameters of larch communities are significantly reduced. At a height of the riverbed 380 m, larch sparse woodlands are marked only by small fragments on the slopes of the southern exposure, or by single trees, often having branched stems and a widely spreading crown. On the left side of the Lednikovoe Lake basin, with a large gap in distance, at an altitude of 470-480 m, single larches of a significant age category are found among the thickets of dwarf pine ( Pinus pumila (Pall.) Regel). These trees have a height of 4-5 m and a widely spreading crown. South of Lednikovoe Lake, at a distance from the lake approx. 8 km to the south-west, at an altitude of about 660 m, we met larch only once. Here, a young solitary tree grows on a small fragment of fine earth among a stone placer covered with epilytic lichens (Lichenes ) . Its stem has a height of 1.3 m. The area we are considering is in the Ozernoe Gorlo River basin, can serve as a reference for monitoring observations of age-old changes in the altitude boundary of forest vegetation.

Over the past 30 years, there have been marked significant increase in the temperature of the upper horizons of permafrost: by an average of 2.5 °C in the Russian Federation. This is related to the degradation trends in permafrost, which negatively affect both natural landscapes and engineering infrastructure. Economic entities try to protect their enterprises by investing both in engineering measures and in monitoring of changes in frozen soils under structures. One of the leading places in this area is occupied by the fuel and energy complex. A system of automated geotechnical monitoring of permafrost soils is beginning to be implemented at its enterprises, and in the near future (5-10 years) this will become mandatory for every structure located in the permafrost zone. But so far, in different regions and organizations, geotechnical monitoring of permafrost is carried out according to different methods, often in a reduced volume without taking into account natural trends and in the absence of appropriate analysis and forecast. At the same time, background changes occurring independently of economic activity are ignored by almost everyone. This drastically reduces the effectiveness of monitoring. The reason, on the one hand, in the shortcomings of the regulations for observations and data processing, and on the other hand, in the fact that in the Russian Federation background geocryological monitoring of natural conditions is carried out in an extremely insufficient volume. As a result, the possibility of a medium-termand long-term forecast of changes in permafrost soils is extremely limited. For the fuel and energy complex, the problem is aggravated by the lack of data exchange between its individual companies both within the regions and at the federal level. The scheme of the federal permafrost monitoring system is proposed based on the creation of a system of federal geocryological polygons, where 2 types of monitoring are combined: background natural environmental monitoring and geotechnical monitoring of land and subsoil users (primarily in the fuel and energy complex).

Isotopic (¹⁸O, D) and chemical composition of atmospheric precipitation (1-2-cm snow layer on the surface of the snow cover and crystalline hoar), that fell in December 2020-January 2021 at anticyclonic weather, extremely low temperatures from -47 to -52 °C and dense ice fogs, has been studied at 6 sites along a 25-kilometer profile from Yakutsk. Samples from the surface of the snow cover are characterized by the lightest compositions (d¹⁸O = -41.04 ± 5.11 ‰, dD = -326.43 ± 34.16 ‰, d_exc = 1.91 ± 7.72 ‰) and are noticeably depleted with deuterium. From the outskirts to the center of Yakutsk, a significant weighting of the compositions has been established (by 10 ‰ in d¹⁸O, by 80 ‰ in dD), a decrease in d_exc (from +10 to -6 ‰), and a 4-fold increase in mineralization due to impurities of calcium carbonate. The isotopic compositions (d¹⁸O = = -30.89 ± 5.62 ‰, dD = -285.88 ± 12.82 ‰, d_exc = -28.79 ± 32.53 ‰) have been established for samples of crystalline rime, which are not typical for any atmospheric sediments, waters and ice of the region. They experience the greatest variations in d¹⁸O (from -24 ‰ in Yakutsk to -37 ‰ at a distance of 25 km from its center); the value of dD varies from -255.4 to -285.9‰, d_exc increases from -80 to +11.5 ‰. The isotopic and chemical compositions of the investigated sediments indicate a significant proportion of technogenic water vapor entering the atmosphere during the combustion of hydrocarbon fuel. Based on the model of the Gaussian mixture and deuterium excess of the studied samples, it has been found that in crystalline hoar, the maximum share of technogenic moisture reaches 26-32 % near heat-generating stations, in the central part of the city - 13-18 %, and on the outskirts - 6.5-8.8 %; in the surface layer of the snow cover - 5-6 % in the central part of Yakutsk and decreases to the outskirts to 1 % or less.

We give the substantiation of the choice of methods and devices for physical laboratory modeling of the process of freezing and heaving of soils in order to study their heaving properties, as well as the parameters of the freezing process to verify the developed mathematical methods of the process modeling. The methods under consideration make it possible in freezing soils to set and control in automated mode the dynamics of the temperature state, the heat and water flows, the sheaving and shrinkage deformations, the moisture and density, the pore hydraulic pressure and the segregation ice release through the use of time-lapse video recording, the simulation of external mechanical and hydraulic loads.

Aufeis fields (or icings) are widespread in the North-East of Russia, and have a substantial impact on many components of landscapes. The public availability of Landsat and Sentinel-2 satellite data has opened up new opportunities for aufeis mapping. Based on satellite images, we have compiled an up-to-date GIS dataset of aufeis fields in the North-East of Russia, and also have analyzed the long-term and seasonal variability of the largest aufeis. Based on the synthesis of historical (obtained in the middle of the 20th century using aerial photography) and satellite data on aufeis, we have prepared a new cartographic product - the Atlas of giant aufeis-taryn of the North-East of Russia. The Atlas had been published in 2021. In this paper, we have considered the approaches to aufeis mapping used in creating the Atlas, and have presented the main characteristics of the aufeis fields based on historical and satellite data. In total, according to Landsat images obtained in 2013-2020, we have found and delineated 9306 aufeis with a total area of 4854.5 km². According to satellite images, 1146 are giant aufeis, i.e. they cover an area of over 1 km². For these giant aufeis, we have analyzed long-term and seasonal dynamics of their area based on satellite images obtained for the period from the 1970s to the present. On this basis, a series of image-based maps have been created, which are also included in the content of the Atlas. We have not found a substantial reduction in their area between 1970s and the present for most of the giant aufeis. We also have found that the largest aufeis in the north-east of Russia is located in the basin of the Syuryuktyah river. Its area immediately after snowmelt period is on average 14.4 km² larger than the area of the Bolshaya Momskaya aufeis, which had been previously considered as the largest aufeis in Russia.

This paper presents the developed analytical model of the functioning of the system of temperature stabilization of soils of the "HET" type, based on the integral method. The paper presents the solutions of numerical and analytical models for temperature stabilization systems of soils of the "HET" type with different lengths of the evaporating part, as well as for the Arctic cities with different climates - Salekhard, Varandey, Igarka. By comparing the results obtained within the framework of numerical and analytical solutions, it has been concluded that the developed analytical model can be used for an express assessment of the functioning of the system of temperature stabilization of soils of the "HET" type for various design solutions and climatic characteristics.