Home – Home – Jornals – Atmospheric and Oceanic Optics 2022 number 2

Neotectonic activity in the area of the Salair Ridge (southern West Siberia) rejuvenated a system of large arc-shaped faults separating the Salair tectonic arc from the adjacent tectonic units. These regional faults, which make up the general tectonic framework of the Altai-Sayan folded area, originated in the late Paleozoic and were repeatedly reactivated in the Mesozoic. The deformation within the major Salair thrust sheet is mainly brittle and follows small fault planes that crosscut the margins of Paleozoic thrusts. The neotectonic faulting controlled the erosion pattern of the territory and produced a reticulate drainage system. The Salair tectonic unit is a single 80 × 250 km block comprising multiple neotectonic blocks, with a relative vertical offset of no more than 100 m in the block interior and 100-200 m at its southern, northern, and eastern borders. The northwestern and southeastern border faults have reverse slip geometry, while the motions on the en-echelon northeastern fault boundary include reverse and right-lateral strike-slip components. The thickness of the Salair thrust sheet estimated from magnetotelluric (MT) data increases in the western direction from 5 to 15 km in the northern block part and from 10 to >20 km in the south. The allochthon base is delineated by a low-resistivity zone interpreted as a horizontal detachment. This boundary formed in the Mesozoic and was rejuvenated at the neotectonic stage. The lithology and deformation of Jurassic sediments filling piedmont basins around the Salair Ridge indicate that the Cenozoic fault pattern generally inherits the Mesozoic framework but differs in about ten times smaller vertical offset.

We present data on the most complete Neogene sections and wells of northern Ustyurt and the Cis-Aral area. The Miocene deposits in the northern chinks and the North Ustyurt depression are composed of sediments of the Tarkhanian, Chokrakian, Karaganian, Konkian, and Sarmatian regional stages of the Eastern Paratethys, which are overlapped by lower Pontian beds. The distribution of thicknesses and facies shows that the North Ustyurt depression remained the main synclinal structure of the region, along which the waters of all Miocene transgressions were spread. Sandy material was brought by the rivers from the north: A sandy lens of Chokrakian age is traced along the Shomishtykol Sor almost to the axial part of the depression. Transgressions were pulsating, and the lower and middle Sarmatian deposits were most widespread. These data are presented as a geologic profile near Beineu Village and as schematic maps of facies for the middle Miocene regional stages.

We present data on the geochemical and Sr-Nd isotope compositions of rocks and on the Lu-Hf isotope composition of magmatic and xenogenic zircons from granitoids and gabbroids of the late Neoproterozoic island arc structure of the Lake Zone. Plagiogranitoids, gabbroids, and quartz diorites (559-542 Ma) formed at the Vendian subduction stage of magmatism, and two-feldspathic granites (~483 Ma) mark Cambrian-Ordovician accretion-collision processes. We have established that the volcanic rocks of the late Neoproterozoic island arc and/or its oceanic base, which formed from the depleted mantle, were the mafic source of plagiogranitoids. This is proved by the overlapping positive εNd values of plagiogranitoids and the host volcanic rocks and by the commensurate εHf values of magmatic zircons from the plagiogranitoids and depleted mantle. The lower εNd values of gabbro and quartz diorites from the Tavan Hayrhan and Shuthuyn plutons, the lower εHf values of zircons from these rocks, and the high (87Sr/86Sr)0 ratios and K2O, Rb, and Th contents point to the generation of these rocks from a less depleted mantle source, namely, mantle wedge peridotites. The isotope composition of the latter changed at the previous subduction stage under the impact of fluids and with the contribution of subducted sediments. The least radiogenic Hf isotope composition of magmatic and xenogenic zircons from Ordovician accretion-collisional two-feldspathic granites of the Ih Zamiin pluton suggests their formation through the melting of the late Neoproterozoic-Cambrian island arc crust with the contribution of more differentiated crustal sources enriched in Th, Nb, and LREE and characterized by low εNd values. The age of xenogenic zircons (≤716 Ma) in the studied granitoids and gabbroids and their similarity in Hf isotope composition to magmatic zircons from the same rocks confirm the formation of the late Neoproterozoic island arc of the Lake Zone in an intraoceanic setting far from ancient continental sources similar to the Dzavhan microcontinent.

We present results of petrographic, geochemical, and isotope-geochemical (Sm-Nd) studies of the Paleoproterozoic terrigenous rocks of the Urik-Iya graben, which formed during three successive stages of extension. We have established that these rocks are both petrogenic (Ingashi and Daldarma formations) and lithogenic (Ermosokha Formation) sediments. It is concluded that the rocks in the lower and, partly, middle parts of the Urik-Iya graben section (Ingashi Formation and Lower Daldarma Subformation) resulted mostly from the disintegration of felsic igneous rocks. The terrigenous rocks in the middle part of the section (Upper Daldarma Subformation) might have formed through the disintegration of both felsic and mafic igneous rocks. The rocks in the upper part of the section (Ermosokha Formation) probably formed from the underlying terrigenous rocks of the Ingashi and Daldarma formations. The Nd model age (2.3-2.5 Ga) estimated for the rocks of the three studied sections points to a predominance of rocks of the Neoarchean and Paleoproterozoic upper continental crust in the provenance.

This paper presents the first data on the mineralogy, geochemistry, and quantitative distribution of suspension determined with the use of sedimentation traps installed in Lake Onego (the exposure time was one year (2019)). The obtained data on the mineralogical and geochemical composition of the recent suspension of the Onego water column are compared with the data for the surface layer of the lake bottom sediments (0-10 cm). Data on the sedimentation rates for the substance determined with the sedimentation traps have been obtained for the first time for Lake Onego. The estimates of the sedimentation rates differ slightly from the results of calculation of the sedimentation rates by radioisotope dating based on the distribution of ²¹⁰Pb activity in the upper layer of bottom sediments in combination with the data on ¹³⁷Cs. It has been established that the mineral part of the dispersed sedimentary matter that entered the lake reaches the bottom sediment without significant changes. The geochemistry of the sedimentation traps is similar in many respects to the geochemistry of the upper part of the bottom sediments (0-10 cm) in different areas of Lake Onego. The dispersed sedimentary material and the bottom sediment differ in the amount of the biogenic part (in the bottom sediment layer (0-10 cm), the biogenic part loses a significant amount of organic matter). The bottom sediments are characterized by a strong predominance of the ferruginous varieties of illite and chlorite, in contrast to the suspension with the prevailing Mg-Fe varieties of these minerals. Degraded mica minerals brought by rivers are regenerated to normal ferruginous illites and chlorites directly in the uppermost part of the bottom sediments. The bottom sediments are characterized by higher manganese and molybdenum contents, and the material from the sedimentation traps, by high mercury contents.

The 2003 Chuya earthquake aftershocks are studied using the data obtained during experiments with dense networks of stations. Density maps of the foci of more than 50,000 aftershocks are compared with the day surface faults and the block structure and tectonics of the focal area. The large shearing strain caused by the Chuya earthquake is accompanied by a spatially intermittent aftershock structure stretching along it. The density maps of long-lasted aftershocks differ in structure from the maps of seismic activity in the initial aftershock area. The study has revealed a relationship between the block structure of the epicentral area and the structure of the aftershock process. The nodes of the intersection of faults with the aftershock area are characterized by reduced aftershock activity. The aftershock process is only partly confined to the block-separating faults. In many cases, the aftershock process is shifted relative to these faults or wanders from them.

A model of the deep electrical conductivity of the Altai-Sayan folded region is presented, which was compiled from the results of three-dimensional inversion of the invariant values of the impedance matrix and three-dimensional impedance data fitting, using the trial-and-error procedure. The obtained electrical-resistivity values were used to estimate the fluid saturation of the Earth’s crust by applying the Shankland-Waff equation. The NaCl salinity of the aqueous solution is taken equal to 170 g/L, for which the fluid saturation is most consistent with the seismic data. The electrical conductivity and fluid saturation of focal zones of earthquakes, activated blocks of the region, and deep faults were studied. Most of the earthquake hypocenters are located above the top of conductors and near deep low-resistivity faults. The position of low-resistivity anomalies correlates with the position of domains with the enhanced attenuation of converted earthquake waves and reduced velocities of compressional waves. The Teelin, Samagaltai, and Kaa-Khem earthquake sources are characterized by maximum fluid contents (0.5-0.9 %), and the Altai, Shapshal, Shagonar, and Bolsheporoshskii sources, by minimum ones (0.1-0.2 %). The fluid saturation of deep faults reaches 1.2 %. The faults characterized by tensile stresses oriented orthogonally to their strike, show the highest fluid contents. A similar pattern is observed for the crustal blocks located beneath depressions. The high fluid contents beneath the Kyzyl Basin and its surroundings correlate with the major compressional-wave velocity deficit beneath it.

Electrical resistivity tomography has been widely applied in prospecting and exploring gold deposits, but its potential for studying placers has not been sufficiently revealed. It is shown on the basis of numerical simulation and the example of field studies that linear anomalies with high electrical resistivity identified in floodplains correspond to gold-promising stream pool and riffle facies. It is concluded from working with alluvial placers in Kamchatka, Altai, and the Baikal Region that electrical resistivity tomography has a high resolution for solving geological problems, which means that it can be used as the main method for prospecting and exploring placers.

The efficiency of the development of an oil and gas field is largely determined by the knowledge of its geologic structure. In the recent decade, complex fractured carbonate reservoirs have attracted more and more attention. This paper is concerned with a new technology for constructing 3D images of complex reservoirs, based on Gaussian beam processing of scattered seismic waves. This technology was developed at OOO RN-KrasnoyarskNIPIneft’ in cooperation with the Trofimuk Institute of Petroleum Geology and Geophysics. To test it, a special synthetic model was constructed, which is analogous to one of the licensed objects of PAO NK Rosneft’. For this purpose, a full-scale 3D seismic modeling was performed, which provided us with synthetic wave fields and made it possible to carry out well-controlled numerical experiments for reconstructing the geologic structure of the object of study. One of the distinctive features of the constructed digital model (digital twin) is the presentation of faults not as some ideal slip surfaces but as 3D geologic bodies filled with tectonic breccias. A series of numerical experiments was performed to simulate such breccias, the geometry of these bodies, and the geomechanical processes of fault formation. To select the parameters of the used method of discrete elements, we used the information obtained by geophysical studies in horizontal wells crossing the fault within the geologic prototype of the constructed digital model.

Stationary non-laser gas analyzers based on the classical differential absorption method have been designed for continuous measurement of the content of nitrogen and sulfur oxides in exhaust gases of thermal power plants natural gas, coal, and fuel oil. The operation of gas analyzers at Russian thermal power plants based on has shown their high sensitivity, reliability, and ease of maintenance. Based on the method of differential optical absorption spectroscopy and UV LEDs, a prototype of a portable low-power gas analyzer has been designed. It is an effective tool for simultaneous trace measurements of concentrations of a number of atmospheric gases. A mercury analyzer has been created based on the atomic absorption method using a capillary lamp with a natural isotopic composition of mercury with a transverse Zeeman effect as a radiation source. A technique for determining mercury in various media has been developed; the sensitivity of the analyzer is 14 ng/m³. The possibility of its wide use for multi-purpose mercury monitoring is shown.

The results of works on the development and use of remote sensing instrumentation for monitoring of the meteorological state of the atmosphere at IMCES SB RAS are considered including, first of all, instruments for active acoustic sounding together with radiometric (passive) instruments for monitoring the temperature and wind structure, turbulence characteristics in the lower atmosphere, and moisture content in the troposphere. A hardware-software complex for monitoring and forecasting the state of the atmosphere over Tomsk and its vicinity and remote sounding stations distributed over the territory under study (test site) are described.

Results of long-term study of the Earth's natural pulsed electromagnetic field in a very low frequency band in different regions are presented. Laboratory and field experiments show a substantial part of the lithosphere component in the field structure, which allows robust instrumental monitoring of spatial lithospheric structures and irregularities and parameters of dynamic lithosphere-cryosphere-atmosphere interaction processes. The hardware, software, and processing techniques developed are briefly described, which allow a wide variety of geophysical research under conditions of distorted electromagnetic fields.

The results of long-term research on the optimization of technological processes for obtaining crystals with high optical quality that meets the requirements of mass production of nonlinear optical elements are presented. The physical nature of the defects that determine the optical losses of nonlinear optical ZnGeP₂ crystals is clarified. Methods and modes of effective post-post processing of single crystals that provide an increase in optical quality are proposed. Precision thermal equipment has been developed for the synthesis of multicomponent compounds and the growth of crystals with controlled properties. The conducted research cycle allowed us to obtain crystals with record absorption coefficients and breakdown thresholds. The dispersion properties of single crystals are investigated. The conditions for phase matching and conversion efficiency of laser pulses of various durations and wavelengths are calculated. Based on the calculations performed, nonlinear optical elements were manufactured, which were used in numerous experiments on the conversion of the frequency of laser radiation. The results of some experiments on frequency conversion in ZnGeP₂ crystals, which were also used in atmospheric trace gas analysis systems, are briefly presented.

In the statistical solution to problems of analysis, synthesis and filtration for systems of the diffusion-discontinuous type, it is required to simulate an inhomogeneous Poisson point process. To simulate the latter, an algorithm is sometimes used based on the property of the ordinariness of the process. In this paper, a modification of this algorithm is constructed using an efficient method for modeling random variables. The statistical adequacy of the method developed was checked by solving test problems.

An implicit scheme of the discontinuous Galerkin method for solving gas dynamics equations on unstructured triangular grids is constructed. The implicit scheme is based on the representation of a system of grid equations in the so-called «delta» form. To solve the resulting SLAE for each moment of time, solvers from the NVIDIA AmgX library are used. To verify the numerical algorithm, a series of calculations were performed for the flow over the NACA0012 symmetric airfoil profile at various angles of attack, and the problem of the flow over the RAE2822 airfoil profile was solved. The results of calculations are presented.

This paper proposes a method for the numerical solution of the direct one-dimensional problem of magnetotelluric sounding. The construction of difference schemes is realized by the local integral equations method. A natural variant of the interpolation of an approximate solution is considered. The estimate of convergence of the approximate solution to the exact one and the estimate of the interpolation error are proved.

It is shown that the algorithm for verifying congruence of square roots of Hermitian matrices proposed earlier by the author can be extended to the considerably more broad class of matrices whose cosquares are diagonalizable and have real spectra.

By an example of the investigation of the Euler equations on Lie algebras, we discuss an approach to the qualitative analysis of differential equations arising in a number of problems of mathematical physics, including rigid body dynamics. The approach proposed is based on a combination of methods of computer algebra and qualitative analysis of differential equations. We consider the applications of computer algebra in the problems of finding stationary invariant sets and studying their stability. For the equations under study, stationary invariant sets of various dimension have been found and their stability in the Lyapunov sense has been investigated.

A method for the search for numerical solutions to the Dirichlet boundary value problems for nonlinear partial differential equations of the elliptic type and of an arbitrary dimension is proposed. It ensures low consumptions of memory and computer time for the problems with smooth solutions. The method is based on the modified interpolation polynomials with the Chebyshev nodes for approximation of the sought for function and on the new approach to constructing and solving the problems of linear algebra corresponding to the given differential equations. The analysis of spectra and condition numbers of matrices of the designed algorithm is made by applying the interval methods. The theorems on approximation and stability of the algorithm proposed for the linear case are proved. It is shown that the algorithm ensures an essential decrease in computational costs as compared to the classical collocation methods and to finite difference schemes.

The relationship between climate warming and processes occurring in communities and populations of terrestrial small mammals, reptiles, amphibians, and arthropods is considered. The studies were conduct-ed at the Yenisei ecological station “Mirnoe” of the A. N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences. The dynamics of climatic changes are shown on the basis of data from seven weather stations located along an almost thousand-kilometer stretch of the Yenisei River valley. The maximum temperature increase for the period from 1972 to 2020 was noted in the spring months, and the more northern the station is, the stronger these changes are manifested. In the XXI century cyclic type of small mammal population dynamics, which was noted for this area earlier, changed to fluctuating one. The number of small mammals in tenth century was lower than in XX century. At the same time, a significant decrease was noted mainly for species whose origin is connected with Siberia. Some new species were recorded for the first time in the territory of the Yenisei ecological station. The banc vole (Clethrionomys glareolus) and the taiga mite (Ixodes persulcatus) appeared on the right bank of the Yenisei, and the gray toad (Bufo bufo) appeared on both banks.

The results of continuous monitoring of the Naroch lakes system, which includes eutrophic Lake Batorino, mesotrophic Lake Myastro and oligo-mesotrophic Lake Naroch, were used to study the question of what factors most affect the long-term dynamics of the state of the lake ecosystem that is under variable load of biogenic elements. The set of continuous series of seasonal mean values of eight parameters of each ecosystem for 1978-2015 was analyzed by methods of singular spectrum analysis (SSA) and principal component analysis (PCA). The third principal component (F3) which contributed 8,2 %, 9,8 % and 13,3 % respectively to the dynamics of ecosystems of Lake Batorino, Myastro and Naroch turned out to be connected with biomasses of phyto- and zooplankton, as well as with the parameters characterizing processes of destruction and biochemical decomposition of organic matter. Comparison of statistical relationships and periods of the dominant cyclic components of the principal components F3 and associated parameters of ecosystems allowed us to conclude that the interpretation of the third main factor under conditions of variable load of biogenic elements depends on the characteristics of a particular ecosystem. For ecosystems that are not deficient in nutrients, it can be interpreted as the transfer of created primary organic matter to consumers of the next trophic level, related to the structure of the food chain in the ecosystem. For an ecosystem in which the process of primary production formation is limited by the available amount of nutrients, it is this available amount of nutrients that is the third main factor affecting its long-term dynamics.

The succession of bird communities in the hemiboreal forests of the Eastern upper Volga region was traced by the method of multidimensional nonmetric scaling (nMDS).Comparison of data on the species composition and bird population density of managed forests, intact forests, and forest reserves. Analysis of the impact of natural and anthropogenic disturbances of various intensity on common and rare species, as well on the stability of hemiboreal ornithocenoses in space and time.

The population of spiders in the intermontane depressions of Southeastern Altai and Tuva was studied using a numerical approach. It has been established that the population is very small in number and taxonomically poor. On the catenas of the Chuya Hollow, subarid species predominated, while in the Kurai Hollow, located in the valley of the large Chuya River, polyzonal species predominated. In Tuva, the driest conditions of the catena on the Tannu-Ola ridge (Uvs-Nur depression, western sector) determined the predominance of subarid faunal elements, as in the Chuya depression. For the same reason, these two catenas were distinguished by the largest proportion of representatives of the Central Palaearctic fauna. On the catenas near lakes Khadyn (Ulug-Khem depression) and Tore-Khol (Uvs-Nur depression, eastern sector), where accumulative positions were characterized by high humidity, the share of subboreal humid species was high. Western Palaearctic species predominated on the catenas in the Kurai steppe and near Lake Khadyn. On the catena near Lake Tore-Khol, there is no dominance of species with any one longitudinal type of range. The dynamic density of spiders was usually highest in the lower catena positions. Under extremely arid conditions, at all catena positions in the Chuya and Uvs-Nur (Tannu-Ola) depressions, the maximum dynamic density was noted at the uppermost positions. The spiders belonging to the families Lycosidae and Gnaphosidae are the most numerous and diverse in the population of spiders in the mountain basins of Southeastern Altai and Tuva. In the isolated conditions of individual hollows, specific spider faunas are formed. Only the transit and accumulative positions on the catena in the Kurai depression are similar in terms of population structure.

The aim of this study is to identify ecological and phytocenotic features and factors of differentiation of plant communities with Heracleum sosnowskyi Manden. in the Kursk region. This region is located on the southern border of the secondary area of this species in the European part of Russia. Plant communi-ties with Heracleum sosnowskyi in the study area are represented by 4 syntaxons. To identify of ecological patterns of their organization, we used the analysis of the composition of differential species and species with the greatest activity, the identification of differences in the ecological regimes of their habitats, and the ordination analysis of relevйs. Each syntaxon differs from the others in a number of environmental factors and is characterized by a group of species with similar environmental requirements. Рredominance of ruderal and eurytopic species in communities and increase of similarity of their floristic composition are manifestations of the negative impact of the distribution of Heracleum sosnowskyi on the vegetation cover. The greatest similarity of coenofloras is found between the derivative communities Heracleum sosnowskyi [Agropyretalia intermedio – repentis] and the association Urtico dioicae – Heracleetum sosnowskyi. Their phytocoenoses represent successive stages of vegetation cover change under the influence of the invader. As a result of the spread of hogweed, the strongest changes occurred in the aboriginal communities, in place of which the phytocenoses of these syntaxons were formed. In communities where Heracleum sosnowskyi forms variants of associations Rudbeckio laciniatae – Solidaginetum canadensis and Chelidonio – Aceretum negundi, the floristic composition and ecological conditions changed slightly compared to typical communities of these syntaxons due to the presence of other invasive species.

The round goby is a small demersal fish considered one of the top invasive fish species. Having settled far beyond its native Ponto-Caspian region, the round goby currently inhabit the basins of the Baltic and North Seas, as well as the Great Lakes of North America. Since 2005, the species has been increasingly occurred in the eastern part of the Baltic Sea - the Gulf of Finland, where one of its northernmost populations was founded. The study is focused on studying the morphological differentiation of the round goby from geographically distant parts of the Gulf of Finland in order to assess the heterogeneity of this population and to suggest the most probable ways of the species penetration and dispersal there. Four samples were compared in 5 meristic and 35 morphometric traits. The traits characterized the number of finrays and rows of scales along the body, the shape of the body and head, and the position and shape of the fins. The comparison was carried out using indices, parametric and nonparametric tests, factorial, cluster analysis and multivariate scaling. Round goby samples collected at a distance of 40 to 270 km significantly differed in body shape, position and size of fins, while other characters were less prominently different between locations. The round goby from the western part of the gulf was the most different from goby of its eastern part, where morphological differentiation between locations was also observed. The results of the study assume the existence of separate round goby populations in the Gulf of Finland, with development of morphological features, associated with local habitat conditions, and the limited migrations of the species within the gulf. On the basis of the results obtained, we suggested independent introduction of the round goby into the western and eastern parts of the Gulf of Finland of the Baltic Sea.

The effect of PEG‑induced drought on the growth, the efficiency of photosystems I and II, and the
accumulation of proline, sodium and potassium ions in plant shoots of two populations of the intermediate
C3-C4 xerohalophyte Sedobassia sedoides was studied. The heterogeneity of plant response to osmotic stress
was revealed, both between populations and within each of them. The relationshi ps between the factors involved
in the adaptive mechanisms of plants from different populations under osmotic stress was determined.
Presumably, the intraspecific variability of S. sedoides plants in the mechanisms of drought tolerance is
associated with the different expression of the C4 photosynthetic syndrome in different populations and soil
conditions, in particular, with the water-salt balance of soil.

This study was conducted to examine the diversity and community structure of saproxylic beetles inhabiting silver birch ( Betula pendula Roth) in the State Nature Reserve “Voroninsky”. Beetles were caught using interception traps that were located on the trunks of birch trees in different decomposition stages. The result of this study showed that a total 1806 individuals of saproxylic beetles, belonging to 96 species and 37 families were sampled. The largest number of species is found in the families Staphylinidae, Tenebrionidae and Mycetophagidae. The largest number of specimens is found in the families Throscidae, Tenebrionidae, Staphylinidae, Lycidae, and Pyrochroidae. Most of the species are facultative inhabitants of the birch tree and are able to develop on other types of trees. More than a third of all the collected specimens belong to six species Lygistopterus sanguineus , Aulonothroscus brevicollis , Schizotus pectinicornis , Mycetochara flavipes , Trixagus dermestoides and Mesosa myops . The species composition and trophic structure of the complex of beetles at different stages of wood decomposition in the surveyed habitat is characterized by high similarity, but the distribution of species and quantitative abundance at different destruction stages differ. In general, complexes of saproxylic beetles at decomposition stages II and III are more taxonomically diverse, which shows the importance of dead wood for maintaining the species diversity of forest communities. Almost all trophic groups were observed at all decomposition stages, only necrophagous ones were found at decomposition stage III. In terms of species and number abundance, mycetophagous ones prevail at all decomposition stages, saproxylophagous ones take a noticeable part in the composition of the complex at the last decomposition stages. The dominant complex includes both mycetophages and saproxylophages ones. The composition of the dominant complexes of different habitats differs at stage I of wood destruction. The analysis reveals connectedness in time to certain stages of wood destruction in 37 species and 5 families. The least pronounced connectedness is at decomposition stage I; the subsequent decomposition stages are preferred by a greater number of species.

Comparative analysis of the size-mass and biochemical parameters (total lipid content and their fractional and fatty acid composition) of eggs of wild and cultured producers of the Ob muksun showed significant differences between them. Wild eggs is characterized by smaller size (by 7 %) and weight (by 15 %), higher fat content (by 13 %) and the level of diacylglycerols (by 33 %), and lower phospholipid content (by 30 %) in comparison with factory eggs. At the same time, factory eggs differs from wild eggs by a higher level of physiologically significant docosahexaenoic 22:6n-3 (1.8 times) and linoleic 18:2n-6 (7.1 times) acids, but a relatively lower level of eicosapentaenoic 20:5n-3 (in 1.5 times) and arachidonic 20:4n-6 (4.2 times), respectively. Such changes in the fatty acid status led to a decrease in the commercial eggs of n-3/n-6 ratio (by 52 %), palmitic 16:0/ oleic 18:1n-9 (32 %) and α-linolenic 18:3n-3/18:2n-6 (by 45 %), and to an increase of 22:6n-3/20:5n-3 (by 63 %). In addition, in the eggs of factory muksun, 68 % of the total lipids are 4 acids - 16:0, 18:1n-9, 22:6n-3 and 18:2n-6, in wild eggs the share of these acids was 47 %. The established differences in the size-mass parameters, the total lipid content and their fractional and fatty acid composition of wild and hatchery eggs of the Ob muksun are most likely associated with a different diet and habitat conditions of the sexually mature fish in captivity and nature.

Trophic position of fish is one of the most important factors controlling the accumulation of potentially toxic elements and compounds in fish tissues, primarily via the spectrum of fish nutrition. In this study, the content of potentially toxic transition metals (Cu, Zn, Mn, Pb, Cd) and radiocesium (¹³⁷Cs) in the edible tissues (muscles and liver) of two representatives of the fish-eating ichthyofauna of the Yenisei River, northern pike ( Esox lucius ) and burbot ( Lota lota ), have been comparatively studied relatively to the size of the fish. A significant decrease in the content of radiocesium and zinc in the muscles of pike, and zinc in the liver of pike with an increase in body size was recorded in juvenile pikes with a body weight ( W ) of less than 0.35 kg. For larger sexually mature pikes, no significant size dependences of the accumulation of metals in tissues were found. A positive correlation was found between the content of ¹³⁷Cs, Cu, Zn and Mn in muscles and the size of burbot in the W range from 0.42 to 1.62 kg. The tissues of one-sized burbots and pikes significantly ( p < 0.05) differed in the concentration of metals in their tissues: concentrations of Zn and Mn were 1.6-2.2 times higher in muscle of burbot; concentration of Pb was 1.8 times higher in muscle of pike; Cu was twice higher in liver of burbot; Zn and Mn were 4.7 and 1.6 times higher in liver of pike, respectively. The revealed differences may be due to the differing food spectra of pike and burbot. Concentrations of Cu, Zn, and Mn in liver of pike were 3-7 times higher than in muscle; concentration of Cu in liver of burbot was 5 times higher than in muscle. Pb and Cd tended to be higher in liver than muscle for both fish species. Despite the revealed size-dependences, the concentrations of potentially toxic metals and radiocesium in the muscles and liver of fish were below the permissible concentrations for food. The results obtained can be used to assess environmental risks for the population consuming fish, as well as to plan long-term environmental monitoring of rivers using representatives of fish-eating fish fauna.

Results of numerical simulations of a supersonic (М_¥ = 7) flow around a cylinder with a gas-permeable frontal insert made of a high-porosity cellular material are reported. A toroidal skeleton model of a high-porosity medium is developed and implemented to describe air filtration in the gas-permeable insert. The aerodynamic coefficients of the cylinder model for various angles of attack ( a = 0¸15°) are obtained. They are found to agree well with available experimental data, which confirms that the proposed skeleton model adequately describes the real properties of high-porosity materials.

Microfluidic liquid-liquid flows exhibit a wide range of different flow patterns. The most important point in practical applications is the transition from the segmented to the continuous flow patterns, as well as the prediction of this transition for an arbitrary combination of fluids. This paper presents a detailed analysis of the existing experimental data on flow patterns of immiscible liquids and provides data generalization through dimensional analysis. It is shown that the previously proposed criterion (We^0.4Oh^0.6) composed from Weber and Ohnesorge numbers provides a prediction on transition continuous-to-segmented flow with good accuracy if viscosity ratio λ = m _d/ m _c is less than unity. For the viscosity ratio λ > 1 this criterion ceases to work, and additional experimental data are required to construct a generalizing parameter for microfluidic flow in such systems.

The present study aims at obtaining the optimum contoured crater for a cylindrical-based film cooling hole with maximum area-averaged cooling effectiveness via computational fluid dynamics and optimization method. The influences of 5 geometrical parameters, which depict completely the dimensions of the contoured crater, were discussed through performing the orthogonal experiment design and range analysis. The optimum designs at blowing ratios of 0.5 and 1.5 were obtained by using the range analysis and the genetic algorithm combined with back propagation neural network respectively. From the analysis of the results, it can be found that the latter optimization method outperformed with higher area-averaged cooling effectiveness at both blowing ratios. The area-averaged cooling effectiveness of the optimized cratered holes were improved by 17.21 % at blowing ratio of 0.5 and 101.96 % at blowing ratio of 1.5, respectively, compared to those of the reference geometry. The improvements on the film-cooling performance were explained in terms of the flow filed and the vortex structures.

The wetting of a surface with a combined texture is investigated. Contact angles are measured for various surface textures. The method for hydrophobic texture formation using a combination of mechanical punching and patterning the surface made on the basis of polymers and aluminum oxide nanoparticles is proposed and analyzed.

The regularities of liquid film formation in the vicinity of capillary holes of a die when starting the droplet generator, as well as the regularities of film rupture and the formation of jets on its surface are experimentally and theoretically investigated. It is shown that the transient processes of film formation and rupture last several seconds, and the defining mechanism of film rupture is the development of bending instability of the jet nucleus.

The paper presents a problem of one-dimensional flow of water and steam separated with an interface; the flow is arranged in an inclined porous layer and subjected to lateral heat flux. The analytical stationary solution was found and the properties analyzed. Instability of flow for a certain region of parametric space was found and the nature of instability was described.

In this paper, energy and exergy analysis has been done for irreversible Brayton cycle with regenerator, reheater, and intercooler. In this work, the influence of the different parameters such as the efficiency of cycle's components surveyed based on the first and the second laws of thermodynamics. The lost exergy in the different components and the total lost exergy of the irreversible Brayton cycle are calculated under several conditions. Also, the optimum pressure of the intercooler and the reheater are obtained under different conditions. To obtain the optimum pressure, irreversible Brayton cycle with regenerator, reheater, and intercooler is simulated in engineering equation solver software and optimum pressure is obtained based on the first and the second laws of thermodynamics in each simulation. The obtained optimum pressures are compared with the geometric mean of the low and the high pressure of the cycle in each simulation.

Results of a numerical study of ignition of a cold supersonic (М_jet = 1.46) hydrogen jet surrounded by an annular supersonic (M_air = 1.86) jet of hot vitiated air expanding into a submerged space are reported. The simulations are performed under the experimental conditions of Cohen and Guile (1969) based on the Reynolds-averaged Navier-Stokes equations supplemented with the k-w SST turbulence model, a detailed kinetic mechanism of hydrogen combustion in air, and various models for taking into account the turbulence-chemistry interaction. The calculations are performed in the ANSYS Fluent 2020 R1 software in a transient two-dimensional axisymmetric approach by using a pressure-based solver. The instantaneous, mean, and RMS components of the main aerodynamic parameters and species mass fractions are obtained. A detailed comparison of the calculated profiles of the Mach number, total temperature, and species mass fractions along the jet axis and in several jet cross sections for non-reacting and reacting flows with experimental data is performed, revealing reasonable agreement in all parameters. It is demonstrated that the use of the transient approach combined with a detailed kinetic scheme makes it possible to reproduce the vortex structures developing at the combustion layer boundary, which make a significant contribution to hydrogen-air mixing, and, thus, affect the hydrogen combustion process.

The article presents experimentally obtained temperature dependences of the degree of blackness of metals of group VIII of the periodic table: cobalt, nickel, palladium and platinum.

Using the methods of mathematical modeling in a single-phase formulation of the Stefan problem, the problem of melting of an ice layer, which scatters radiation, was formulated and solved. To solve the radiation part of the problem, a modified method of mean fluxes was used. Anisotropic scattering was taken into account using the method of expansion of the scattering indicatrix in terms of Legendre polynomials. The influence of the scattering direction on the rate of ice layer melting is shown. Satisfactory agreement of the calculation results with the experimental data and with the data of calculation by the transport method has been obtained.