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We consider the usefulness of satellite data to estimate atmospheric instability and precipitable water vapor for the cases with severe convective events occurred over the European Russia and the Ural region. The initial sample includes 305 squalls, tornado, and large hail events. We evaluated the values of the instability parameter Lifted Index (LI) and precipitable water vapor (PW) using MODIS Atmospheric Profile Product data as well as the ERA5 reanalysis data. It was found that the median values of LI and PW according to the MODIS and ERA5 data are rather close, while the extreme values substantially differ. Local areas with very strong instability and high PW were identified from MODIS data, but not detected according to the reanalysis data. We found major limitations of the MODIS data associated with rather low frequency of imagery and the lack of information on the instability parameters for cloudy pixels. In particular, it reduced the sample size from 305 to 95 cases.

We discuss the results from measurements of aerosol physicochemical characteristics in summer 2021 in the Greenland-Kara sector of the Arctic Ocean (83rd and 84th cruises of RV “Akademik Mstislav Keldysh”). The studied characteristics included: the aerosol optical depth of the atmosphere, the aerosol and black carbon concentrations, as well as the chemical composition of aerosol samples, i.e., the concentrations of main elements, the concentrations of organic and elemental carbon, and the isotopic composition of carbon. For the most aerosol characteristics we noted lower average values as compared to the three preceding expeditions. Data from five expeditions are used to estimate the differences in the aerosol and black carbon concentrations among the Kara, Barents, Norwegian, and Greenland Seas.

The results of long-term (2007-2021) complex experimental studies of microphysical parameters, mass concentration and elemental composition of aerosol particles in the surface air layer of semiarid zones in the south of European Russia are presented. Background values of the daily average mass concentration of near-surface aerosols in the deserted areas of Kalmykia and dry-steppe zone of Rostov region are estimated for the hot summer period: 125 and 34 mg/m³, respectively. The particle size distribution functions typical for atmospheric aerosols of the regions under study are determined. The processes of aerosol particle removal are studied in connection with the main atmospheric processes. Insignificant variations in the mass concentration of only Cd, Hg, and Cu are revealed in aerosols in Rostov region. The elemental composition of Kalmykia aerosols is more variable in both natural and man-made elements, mainly in chemical elements of salt balance and heavy metals. It is shown that most elements are weakly accumulated in aerosols, and their differentiation depends more on the mosaic of the underlying surface. During the long-term period under study, a trend toward purifying the deserted territories of the south of European Russia from harmful atmospheric impurities is found, presumably as a result of reducing climate aridization and/or anthropogenic effect.

The problem of optimizing the bearing capacity of a stringer panel with a hole and a straight crack propagating from its contour is considered. The goal is to determine a hole contour at which the stress intensity factor in the vicinity of the crack tip is equal to zero (i.e., the crack is immobile) and at which the maximum circumferential stress is the smallest. A minimization problem is solved using the method of successive approximations, the minimax criterion, and the simplex algorithm.

This paper presents a volumetric feeder of non-free-flowing powders which is comparable in dosing precision to weighing systems. The efficiency of the main units was studied numerically (using the discrete element method) and experimentally. A continuous high-precision volumetric feeder design is proposed.

The spatial vibrations of a pipeline on two supports vibrating in the vertical direction with equal amplitudes and phases are considered. The pipeline movement consists of rotation (rolling) around a straight line passing through the supports and bending deformation. It is assumed that the bending occurs in the rolling plane without torsional deformation. Nonlinear equations of bending and angular motion of the pipeline are used. The pipeline movement was studied in the case where the bending is much more influenced by the internal pressure of the medium in the pipe than by its weight. The ranges of input parameters in which the upper and lower bent states of the pipeline are stable are determined by analogy with the Kapitza pendulum. Numerical calculations were carried out for a reinforced magnesium tube filled with methane.

The initiation of an edge annular longitudinal shear crack (III fracture mode) during torsion of a circular cross-section bar made of an elastoplastic material with ultimate strain is considered. The fracture process of such materials is described using a modified Leonov-Panasyuk-Dugdale model, which uses an additional parameter - the diameter of the plastic zone (the width of the prefracture zone). To obtain the critical parameters of quasibrittle fracture, a double (sufficient) strength criterion for mode III cracks in an elastoplastic material is proposed. Diagrams of quasibrittle fracture of a circular shaft with an edge crack are plotted. For quasiductile and ductile types of fracture, the ultimate loads are found numerically by the finite element method. The difference between the numerical and analytical models is that the characteristics of the investigated materials correspond to the deformation modes in full-scale yielding. It is found that the results of numerical experiments are in good agreement with the results of calculations using the analytical model of fracture of specimens during torsion in the mode of small-scale plastic flow.

This paper presents the results of the numerical calculation of gas filtration in a low-permeability gas formation with a fractured well. It is assumed that finite-conductivity filtering is described by Darcy law. The Peng-Robinson equation was used to take into account the dependence of the PVT properties of the gas on pressure. We studied the effect of fracture conductivity and formation permeability on the distribution of pressure and gas properties in a “fracture-formation” system and on the dynamics of pressure of the well and the gas production rate in the well during well-testing.

The mechanisms of the coagulation-based water purification using titanium-containing coagulants were studied. Investigation of colloidal systems formed during hydrolysis of traditional coagulants based on aluminium and iron compounds, as well as innovative and promising titanium-containing coagulants, was carried out. The surface characteristics (surface charge, specific surface area) of hydrolysis products of titanium compounds were determined under conditions close to those of the coagulation water purification. The surface characteristics of the products of hydrolysis of traditional and titanium coagulants were compared. It has been established that the hydrolysis products of titanium compounds carry a negative charge on their surface, and their surface that is extremely developed in comparison with traditional coagulants, which indirectly confirms their ability to adsorb pollutants. The sedimentation characteristics of the resulting hydrolysis products of various coagulants were studied. It was shown that the coagulation slimes formed as a result of the use of titanium-containing reagents have a larger flake size, which means they quickly settle to the bottom during settling. The increased efficiency of complex titanium-containing coagulants (Al-Ti) due to the phenomena of charge neutralization and nucleation on the surface of hydrolysis products of titanium compounds has been confirmed and scientifically substantiated. Evaluation of the efficiency of titanium-containing coagulants in the purification of drinking water from the Moscow water intake was carried out. It was found that in the purification of water from the surface water intake, titanium-containing reagents significantly exceeded traditional reagents in the effectiveness (a decrease in the content of suspended solids, colour index), and residual concentrations of titanium compounds in purified water meet the requirements of drinking water quality standards (0.1 mg/L). The sediments obtained with the use of titanium-containing coagulants were distinguished by an increased sedimentation rate and more readily gave up moisture during the filtration process, which would allow reduction of the dimensions of the treatment equipment.

Concentrations of organochlorine compounds (OCs) were determined, and comparative analysis of OCs in the bottom sediments of the Chernaya river, small lakes of the Baydar valley, the Sevastopol Bay and the Chernorechensky reservoir, sampled in 2008 and 2019-2020, was carried out. A noticeable difference in the levels of pollution with OCs in the river, lakes and the bay was detected. This concerns mainly such OCs as polychlorinated biphenyls (PCB), the content of which in sediments of the studied areas varied within a wide range - from 0.5 in lakes to 900 ng/g dry mass in the Sevastopol bay. Increased anthropogenic pressure on the river water area in the region of Baydar valley and in the estuary area has led to the formation of zones with the local maxima of the concentrations of PCB and organochlorine pesticides (1,1,1-trichloro-2,2-bis(chlorophenylethane), DDT) in the bottom sediments of the Chernaya river. In the Baydar valley, the sediments in lakes were on average less contaminated than river sediments, which is due to the isolation of lake ecosystems; they may be classified as non-polluted and weakly polluted. The maximal OCs concentrations were detected in the Sevastopol Bay. The ratio of DDT metabolites in the composition of organochlorine pesticides depended on redox conditions in bottom sediments: under anaerobic conditions of the Sevastopol Bay, DDT was transformed into DDD (1,1-dichloro-2,2-bis(4-chlorophenyl)ethane), under aerobic conditions in the river sediment - into DDE (1,1-dichloro-2,2-bis-(4-chlorophenyl)ethylene). Reconstruction of sedimentation geochronology using radiotracer methods shows that the variability of OCs content at different depths of fresh-water sediments depended on the temporally varying amounts of OCs income into the water areas but not on the natural conditions of sediment formation. According to estimates, at present, the runoff from the Chernaya river contributes not more than 14 % ∑DDT and 4 % ∑6PCB into the bottom sediments of the Sevastopol Bay.