Home – Home – Jornals – Atmospheric and Oceanic Optics 2021 number 2

This Special Issue celebrates the 85th anniversary of Nikolai Leontievich Dobretsov, Full Member of the Russian Academy of Sciences. The opening paper presents a brief outline of the contributions related to the scientific interests of the hero, which, however, far transcend this limited scope. Hardly there is a field in geosciences where Nikolai Dobretsov would not leave a significant footprint. All over the course of his scientific carrier, he has been prolific in generating new ideas, which he shared generously with the colleagues and numerous disciples. Their papers published in this volume concern key issues of the deep structure and general evolution theory of the planet Earth, including various historic aspects of the geomagnetic field, its relation with the gravity field and with the periodicity of geologic processes, as well as global plate tectonics and plume activity through the Earth’s history. The problems of deep structure are discussed for the cases of the Central Asian Orogenic Belt and the magmatic system feeding the Kamchatka volcanoes. The volume is completed with several papers on metallogeny of the Central Asian orogen and the Russian Far East, especially gold mineralization, which was among principal subjects investigated by N. Dobretsov.

We present a summary and analysis of current views on the magnetic and gravity fields of the Earth as a reflection of global and regional tectonic processes. The discussion concerns the probable interconnection among the distribution of the geomagnetic field characteristics, gravity anomalies, and the manifestations of mantle plume magmatism as the most remarkable geologic indicator of deep geodynamics. We demonstrate that the distribution of the characteristics of the main geomagnetic field has a qualitative similarity to anomalies of the gravity field. Brief variations in the geomagnetic field are due to high-frequency oscillations in the ionosphere, do not affect the general state of the field, and are useless when considering issues of global tectonics. On the contrary, variations with long periodicities, first of all geomagnetic reversals, can be among the main indicators of the evolution of the geodynamo, the heat mechanism controlling the entire series of global tectonic processes. The frequency of reversals is determined by the intensity of mantle plumes that cause the cooling of the core, increase the convection rate in the asthenosphere, and accordingly, the periodic changes in the tectonosphere. We assume the existence of three modes of behavior for this system. The first one corresponds to steady convection, in which reversals are extremely rare or do not happen at all. These episodes, superchrons, make up no more than 20% of the duration of the Phanerozoic. The second mode occurs significantly more often in the geologic history and is characterized by active convection with frequent reversals happening at least once every five million years. Finally, the third mode, which is rare for the Phanerozoic but was probably more prevalent in the early Precambrian, corresponds to hyperactive turbulent convection, when the frequency of reversals reached 20 and possibly more during one million years. Although the demonstrated qualitative similarity in the position of extreme values of the main geomagnetic field, the centers of free-air gravity anomalies, and manifestations of large igneous provinces does not yet have a credible explanation, we consider it to be fundamental and requiring special study and detailed elaboration.

The time span between 3 and 2 Ga in the geologic history encompassed a number of key events on the cooling Earth. The cooling interrupted heat transfer within and across the mantle, which caused changes in the Earth’s major spheres and in the mechanisms of their interaction. The great thermal divergence at 2.5 Ga and differentiation into the depleted upper asthenospheric and primitive lower mantle affected the compositions of oceanic basalts. The lower-mantle cooling recorded by а systematic decrease in the temperature of komatiite magma generation at the respective depths began at 2.5 Ga and was accompanied by increasing abundance of arc basalts and by changes in the behavior of the Sr, Nd, and O isotope systems. It was the time when the continental lithosphere consisting of subcontinental lithospheric mantle and crust began its rapid growth, while the crust became enriched in felsic material with high contents of lithophile elements. Magmatism of the 3-2 Ga time span acquired more diverse major-element chemistry, with calc-alkaline and alkaline lithologies like carbonatite and kimberlite. The dramatic changes were driven by subduction processes, whereby the crust became recycled in the mantle and the double layer (D″) formed at the core-mantle boundary. The events of the 3-2 Ga interval created prerequisites for redox changes on the surface and release of free oxygen into the atmosphere. In terms of global geodynamics, it was transition from stagnant-lid tectonics to plate tectonics regime, which approached the present-day style at about 1.8-2.0 Ga.

The use of space-geological information permits generalization of studies of various active geologic processes in a new way. As reference examples, we consider geologic regions extensively covered by research with our contribution. The joint use of satellite images, maps of gravity anomalies, and seismic-tomography data for Kamchatka made it possible to construct 3D models of surficial and deep-seated (depths from 10-50 to 650 km) volcanic structures. For young volcanosedimentary structures of Kamchatka, it is possible to trace the interaction of various processes, from crystallization of magmas in magma chambers to ore and oil formation in calderas. Ancient tectonic structures and superposed Cenozoic deformations in the Tien Shan, Altai, and Baikal regions are clearly displayed in satellite images and on maps of gravity anomalies. The long-range impact of the Indo-Eurasian collision on the Tien Shan, Altai, and Baikal regions was expressed as shearing, which resulted in the most contrasting structures in the zones of junction of regional faults and along the framing of cratonal structures. The active structures of Gorny Altai contain numerous travertines, whose abundance is correlated with seismic activity. The mass formation of methane and gas hydrates in Lake Baikal might be related to mantle plume fluids.

The Klyuchevskoy group of volcanoes (KGV) located in the central part of Kamchatka is a unique complex that demonstrates exceptional variety and intensity of volcanic manifestations. These features of the eruptive activity of the KGV are determined by a complex system of magmatic sources in the crust and mantle. While the structure of deep anomalies is quite reliably determined by tomography technique based on body waves, the structure of the upper crust can only be determined using ambient noise tomography. We present the results of processing data from the KISS temporary network. This network consisted of more than 100 seismic stations that were installed from 2015 to 2016 over a large area covering the Klyuchevskoy group of volcanoes and its surroundings. To retrieve Rayleigh surface waves, cross-correlation of continuous seismic noise records from pairs of stations was used. We obtained the dispersion curves of the group velocities of these Rayleigh surface waves using frequency-time analysis (FTAN) of the calculated correlograms. These curves served as input data for performing ambient noise tomography. Tomography was performed in two stages: (1) computation of two-dimensional group velocity maps for different frequencies and (2) calculation of a three-dimensional model of the shear wave velocity to a depth of about 8 km based on the inversion of local dispersion curves obtained from these maps. The resulting models revealed the structural features of individual volcanic systems of the KGV. High velocities were observed at shallow depths beneath the large basaltic edifices of the Ushkovsky and Tolbachik volcanoes. At greater depths, while the velocity structure beneath Ushkovsky remained unchanged, we detected low velocities beneath Tolbachik. This fact illustrates the difference between dormant and active magmatic systems. Velocity anomalies of a complex shape are observed beneath the Klyuchevskoy, Kamen, and Bezymianny volcanoes, varying both laterally and with depth. Absolute velocities in vertical sections show that the edifices of these volcanoes are relatively low-velocity bodies located on a horizontal high-velocity basement. A low-velocity anomaly was discovered under the Bezymianny Volcano at a depth of 6 km, which is presumably associated with a shallow magma reservoir. An intense low-velocity anomaly was found beneath the Udina Volcano. It was interpreted as an image of a magma reservoir experiencing strong seismic unrest that began in December 2017 and continues to this day.

Studies of melt and fluid inclusions and minerals as well as computational modeling (based on the data on the composition of melt inclusions, clinopyroxenes, and amphiboles) gave an insight into the physicochemical parameters of magmatic systems during the evolution of the precaldera Pra-Gorely Volcano and during the subsequent formation of rock complexes of the Young Gorely Volcano. The estimated temperatures of crystallization of olivine, clinopyroxene, and plagioclase phenocrysts (1115-1260 ºС) and amphibole (740-890 ºС) are in agreement with the earlier published data on the magmatism of the Gorely Volcano. Computational modeling based on the compositions and homogenization temperatures of melt inclusions showed that the established depth interval of mineral crystallization (21.0-1.5 km) with pressures of 7.0-0.5 kbar can be divided into two ranges, 21-15 km and 9.0-1.5 km. Both the Pra-Gorely and the Young Gorely volcanoes have magma chambers in these depth ranges. The Pra-Gorely Volcano is characterized by higher temperatures of mineral crystallization (1240-1190 ºС) as compared with the Young Gorely Volcano (1190-1125 ºС). The presence of primary fluid inclusions with low-density CO2 and of syngenetic primary melt inclusions in plagioclase of the Pra-Gorely Volcano indicates that the mineral crystallized from a heterophase melt. At the same time, the cores of plagioclase phenocrysts formed from a homogeneous melt. A drastic drop in pressure led to the phase separation of magma throughout the magma column (upper and lower chambers) and to the growth of zones saturated with CO2 fluid inclusions in the plagioclase crystals formed from a two-phase melt. The subsequent closure of the system and the disappearance of CO2 phase resulted in the growth of plagioclase from a homogeneous melt.

Comprehensive studies of structural geology and metallogeny, taking into account the authors’ previous works started as early as the last century, have shown that the southeastern part of East Sayan formed mainly in the Neoproterozoic-early Paleozoic in the settings of multistage thrust and nappe tectonics and tectonomagmatic restructuring of autochthonous and overthrust allochthonous oceanic (ophiolitic), island arc, and ocean-marginal terranes as well as amalgamation of accretion-collision and postcollisional igneous complexes that formed during the opening and subsequent closure of the Paleoasian Ocean marginal structures. In the middle and late Paleozoic, active intraplate volcanic and plutonic processes continued in the thrust/overthrust fault setting, which led to the formation of new dome-shaped nappe structures and the redistribution of ore matter (gold etc.) in large mineral deposits. The final structure of the East Sayan region formed during the late Cenosoic as a result of mountain uplifting and volcanic eruptions, including those in the valley of the Zhombolok River.

Geological, mineralogical, and geochemical studies of copper and gold mineralization in the Bumbat ore district of Mongolia have shown its association with igneous rocks of different ages formed under different geodynamic, geologic, and geochemical conditions. Copper ore occurrences (site 98 and Altan Gadas site) with an age of 518.0 ± 4.9 Ma have similar mineralogical and geochemical features and seem to be related to plagiogranite-porphyry stocks formed at the late island arc stage (524.5 Ma). The ores were deposited from weakly concentrated solutions with a low content of СО2 at 240-230 ºС under subsurface conditions. The association of mineralization with plagiogranites, its localization predominantly in veins, and essentially copper composition with high contents of Zn, Mn, Ba, and, in some samples, Ag and Bi permit us to assign this mineralization to the vein quartz-sulfide type. Its commercial value has yet to be assessed. Gold mineralization of the Three Hills and Darvi sites formed later (455.9 ± 4.3 Ma), during the formation of the final granitoid phases at the accretion-collision stage (511-465 Ma). These sites are mineralized crushing zones composed of hydrothermally altered rocks of sericite-quartz composition with veinlet and disseminated (stockwork) sulfide mineralization and gold-bearing quartz veins. The content of gold in the ores varies from tenths to tens of ppm, and its fineness varies from 700 to 1000 ‰. The ores of both sites have high contents of Cu, Zn, Mn, Ba, and, in places, Mo. Mineralization formed from hydrothermal solutions with TDS = 9.5-12.0 wt. % NaCl eq. at medium temperatures (230-300 ºC) under subsurface conditions. The above specific features of gold mineralization are typical of the flank zones of porphyry Cu-(Mo) deposits.

We present results of geochronological studies of rocks from different igneous complexes and of hydrothermally altered volcanics with commercial Au-Ag mineralization from the Pokrovskoe deposit. The age of the ore-hosting granites of the Sergeevsky pluton of the Upper Amur complex is estimated at ~129 Ma. The primary age of dacites of a sill-like body is within 128-125 Ma and is close to the age of volcanics of the Taldan complex. Propylitization processes superposed on these dacites are dated at ~122-119 Ma. Taking into account the commercial contents of gold and silver in these rocks, we believe that the age of the hosted orebodies is in the same interval. The period 122-119 Ma is also the time of formation of the Gal’ka volcanic complex in the Umlekan volcanic zone, which was accompanied by granitoid magmatism. This suggests that the formation of the Pokrovskoe deposit was associated with the accumulation of the Gal’ka complex.

The results of experimental and theoretical studies of the evolution of the small-scale transverse structure of high-power femtosecond laser radiation propagating in air in the multiple filamentation mode are presented. It has been found that the presence of intensity inhomogeneities in the initial transverse profile of a laser beam leads to the formation of high-intensity light channels due to the Kerr-induced self-focusing effect. When the power in these channels exceeds a certain threshold value (the critical power), the filamentation in these structures is implemented. Parameters of these light channels are theoretically estimated on the basis of the diffraction-ray model of single filamentation. It is shown that the initial radius of intensity inhomogeneities in the transverse profile of a laser beam with a centimeter radius and subterawatt power is of characteristic value of several millimeters.

The results of numerical simulation of femtosecond laser pulse propagation in main atmospheric gases (N₂ and O₂) under the effects of coherent Raman scattering are considered. It is shown that when femtosecond 2p-pulses propagate through a gaseous medium, SRS regime is implementable, under which energy losses are insignificant.

The H₂O foreign-continuum absorption in the IR region is regarded according to the asymptotic line wing theory presenting absorption as a sum of the individual line absorption coefficients with a special line shape at far distances from the line center. The line shape parameters pertaining to quantum and classical Н₂О-N₂ interaction potentials are found as a result of fitting the experimental absorption data in the 4200-5000 cm^-1 spectral interval and the data on the temperature dependence of the second virial coefficient. This line shape is used for calculation of the continuum absorption in the 1000-10000 cm^-1 region.

The problem of retrieval of the spatial distribution of the average air density in a supersonic jet from the results of laser transillumination is discussed. It is shown that for axially symmetric flows, the retrieval can be carried out on the basis of the Abel transforms from measurements of local wavefront tilts. An algorithm for retrieving the average density from the transilluminating wavefront deviations transverse to the jet axis has been developed and tested in experiments at the Vertical Jet Device of ITAM SB RAS. The results are in a good agreement with both the data of contact measurements known from the literature and the results of numerical solution of the hydrodynamic problem.

The event of the autumn transport of PM₁₀ from the east to the Black Sea water area and coastal zone is studied. Optical characteristics of the suspended particles are analyzed based on field and satellite data. A correlation is shown between the variability of optical characteristics of PM₁₀ and an increase in the fluorescence intensity of dissolved organic matter in the sea surface layer, measured at the northeastern coast of the Black Sea from the “Professor Vodyanitsky” research vessel.

The concentrations of heavy metals (or metal oxides) and arsenic in samples of atmospheric aerosol and soil collected in northern Tajikistan in 2011 to 2019 are determined. Their local sources, mainly anthropogenic (automobile transport, metallurgical enterprises, open tailing dumps, etc.) are discussed. Possible sources of air transport of pollutants to the territory of the Sogd region are identified on the basis of the HYSPLIT back trajectory model

Results of laser granulometry of nanodispersed fraction of aerosol substance and UV spectrometry of water washes of different-age needles of four plant species are given. Influence of hydrothermal conditions on temporal variability of morphometric parameters of needles and contamination of its surface by phenolic compounds in composition of secondary organic aerosols is evaluated. A mechanism for generating secondary organic aerosols on the surface of different-age needles during efflorescence of phenolic compounds and their subsequent entry into the forest canopy during turbulent separation of the boundary layer from the sheet surface is discussed.

Climatic fluctuations are among the most important factors causing changes in terrestrial and aquatic ecosystems. The review considers the main mechanisms of the influence of climate change on the structure and functioning of ecosystems of water bodies and shows the need to consider these mechanisms when developing a strategy for the conservation of biological resources of aquatic ecosystems. Climatic fluctuations affect aquatic ecosystems through changes in temperature, surface runoff of nutrients and other substances and their relationships, the intensity of water mixing during the circulation period and other mechanisms. Additional nutrients that come in rainy periods from the catchment and directly with precipitation stimulate the development of primary producers and cause the risk of further eutrophication of water bodies. An increase in temperature promotes the development of potentially toxic phytoplankton species and exacerbates the problem of “green tides,” the massive development of multicellular algae in the coastal zone. Organic substances coming from the catchment area during wet periods stimulate a “microbial loop” in aquatic ecosystems. In shallow lakes, climate fluctuations can cause food web dynamics and a change in ecological regime. Climate-induced changes in the composition of producer communities often lead to weakened pelagic-benthic relationships in aquatic ecosystems. Climate-induced changes in the composition of phytoplankton often lead to weakening of pelagic-benthic coupling in aquatic ecosystems. In some cases, climate change has contributed to invasions of alien species. The natural dynamics of ecosystems due to climate fluctuations deserve close attention and require the development of special adaptive management of aquatic biological resources. In some cases, it is necessary to apply more severe measures for the protection and restoration of water bodies, which would take into account adverse changes in the natural background that occur with long-term changes in natural factors.

Results of continuous monitoring of the Naroch lake system, which include the eutrophic lake Batorino, mesotrophic lake Myastro and oligo-mesotrophic lake Naroch, had been used to study the question of what factors most affect the long-term dynamics of the lake ecosystem, which are under a variable nutrient loading. The set of continuous series of average seasonal values of eight parameters from each ecosystem in 1978-2015 was analyzed using the methods SSA and PCA. The second principal component (F2), which contribution to the dynamics of lake ecosystems Myastro, Batorino and Naroch were 15.3 %, 20.5 % and 22.1 %, respectively, was associated with only three parameters that reflect the processes of formation and decomposition of organic matter. Comparison of the periods of the dominant cyclical components of the principal component F2 and related ecosystem parameters allowed us to interpret the second main factor behind these components as the activity of solar radiation.

The article presents the results of study species and trophic structure of macrozoobenthos community in the littoral zone mesotrophic Obsterno Lake (Republic of Belarus) having different macrophyte beds ( Chara , reeds, lily). The results of ANOVA shown the influence of studied biotopes on the number of species and Shennon index. The number of species increased from summer to autumn, but Shennon index was minimal in the middle of summer. The significant differences in species abundance between biotopes obtained for oligochaetes, chironomids, active filter feeders, and predators. There no differences for Ephemeroptera and Trichoptera . The mean values of species similarity for the studied period were 68.9, 74.1, and 70.0 percent for reeds, lily, and Chara , respectively. The trophic similarity between groups were 66.3, 54.1, and 69.7 percent. The significant differences between species and trophic similarity pointed out only for the lily beds. The values of variability species structure during studied period are higher than trophic structure, i. e. trophic structure is more stable to compare with species stru

The body shape variability of perch populations in the mountain and semi-mountain reaches of the Loz’va river basin and adjacent lakes Prostaptur and Elesinskoe (Northern Urals) was investigated by geometric morphometrics using box truss method. 23 distances between homologous landmarks were used to describe the body shape variability of fish. About 33 % of the total shape variance in perch is due to the perch inhabiting the gradient of the locations along the river. The spatial variability of the perch body shape in different river reaches 1.3 times exceeded the scale in shape variability which is associated with river and lakes habitats and 1.6 times exceeded the scale of the morphological shift in perch in the lake Prostaptur. A low intra-group diversity of body shape was identified for the perch population in the lakes with a periodic oxygen-deficient in water. The perch from the river with their strong turbulence of mountain currents, variable water-levels of the watercourse and water flow paths have an increased intra-group body shape diversity. It may indirectly indicate some ontogeny change in the individuals from the mountain river, related to the formation of a wide range of ontogenetic trajectories and suggests a greater perch adaptation to periodic low dissolved oxygen in the lakes than to changes in the hydrodynamic regime of the mountain river.

One of the possible consequences of climate change is a change in the demographic dynamics of phyllophagous insects. For a retrospective analysis of this dynamics, tree rings are used, especially in regions with limited documentary data. Due to the complex nature of the factors determining tree growth, in order to more clearly identify pest-induced defoliation in tree-ring chronologies one suppress the climatic signal expressed directly or indirectly (through chronologies of non-host tree species). However, in the South Siberia, the choice of non-host species is hampered by the wide distribution of polyphages, like gypsy moth ( Lymantria dispar Linnaeus) and Siberian silk moth ( Dendrolimus sibiricus Tsch.). Therefore, the analysis of pest outbreaks in larch forests of the Republic of Tuva low mountains was started by removing the climatic response based on instrumental data, identifying depressions in the residual time-series of individual trees’ radial growth at several sites, and comparing them with available actual data on forest damage by phyllofages. Dendroclimatic analysis showed that the model including the precipitation-to-maximum-temperature ratio for June-September of the previous season and June of the current year, i. e. the degree of aridity during the previous and current growing season, describes 43.7 % of the regional variation in the growth of Siberian larch ( Larix sibirica Ledeb.). After removal of this component, several periods of larch growth depression were revealed during confirmed outbreaks of the Siberian silk moth, gypsy moth, and larch tortrix ( Zeiraphera diniana Gn.). Use of documented data over 1998-2016 allowed to clarify the threshold values of the portion of affected trees for intensities of the growth depression ranging 1-1.5 standard deviations, providing the required reliability of the outbreak reconstruction. The dependence of the spatio-temporal patterns of growth depression on the pest species was revealed, reflecting their migration in the affected area. It has been shown that growth depressions may be delayed compared with the actual damage by pests due to the long recovery after recurrent defoliation.

As a result of the analysis of all data on the number and distribution of small mammals in Western Siberia over the past 120 years, it was found that 20 of their 28 species, recorded in the Northern taiga, form their communities. In the communities of small mammals of the Northern taiga, a similar structure of dominance is generally preserved. The main dominant species: red vole, medium and common shrews predominate almost everywhere. Other 6 codominant species (small and tundra shrews, and housekeeper’s, dark, red and red-gray voles) dominate only in certain areas. The remaining 11 species, both widely and narrowly distributed, make up a small part of the communities. The increase in the species richness of communities in the Eastern direction (from 15 to 19 species) is determined by the increase in the number of Siberian species. In General, in the studied area of the Northern taiga, the largest contribution to small mammal communities is made by representatives of the Siberian type of fauna, with the exception of the Western part of the subzone, where European species predominate.

We sampled ground beetles Pterostichus montanus in 1988-2014 at different altitude plots of Barguzin ridge (N 54°30′; E 109°50′) - the coast (500 m a. s. l.), low mountains - 720 m, middle mountains - 1004 m and high mountains - 1667 m. Morphological measurements included six traits - the length and the width of elytra, pronotum and head in males and females separately. Sample size was 968 individuals. Altitude and sex affected significantly beetles size: the latter was smallest at the coast, at the other altitudes beetles did not differ in size. Sexual size dimorphism (SSD) was female-biased and its value was the highest in elytra and head width. Mean values of SSD by all six traits were the lowest on the low mountains populations. Reduced regression models coefficients were positive in all cases. Then body size variation in males and females had similar direction at all altitudes. But Intercepts were negative in majority of cases and linear regression coefficients more than 1. Thus, males were more sensitive to environment impact practically by all traits.

Artemisia gmelinii Web. ex Stechm. is a shrub, mesoxerophyte, pan-Asian area. A. gmelinii has found application in folk medicine. The composition essential oil has been studied for plants growing in different parts of the area. This article demonstrated on the composition of essential oils of plants growing of the Рriolkhonian flora (Lake Baikal), in particular in Aya Bay. Raw materials were collected during expeditionary work in 2019. Essential oil was obtained by hydrodistillation from air-dried raw materials in the year of collection. Oil analysis was performed by chromatography-mass spectrometry. Data on the composition of the essential oil for visualization were processed using the principal component analysis. The γ-amorphous, isochumbertiol B, caryophyllide oxide, caryophylla-4 (12), 8 (13) -diene-5α-ol, ylangenol, caryophyllylene and cabrevia oxide B are dominant components of the essential oil of plants from Aya Bay. Based on our own and published data we show that the component composition of essential oils is the result of the action of abiotic and biotic environmental factors and and ensures the best adaptation of plants to growing conditions. On the other hand, regardless of the place of plant growth, the directions of biosynthesis of the constituent essential oils are preserved, which makes it possible to distinguish various chemotypes of essential oils. The composition of the essential oils can be divided into two chemotypes: the “Indian” is characterized by a high content of irregular monoterpenoids in the composition and the “Siberian” - of monoterpenoids such as Menthane terpenoids. Among the plants of the “Siberian” chemotype, there is a tendency to the formation of two lines - the western with a prevalence of camphor terpenoids (camphor, borneol, etc.). In the eastern (alpine) sector of the range, the accumulation of sesquiterpenic compounds in essential oils.

The features of the composition and structure of soil microarthropod communities formed on ash dumps of combined heat and power (CHP) plants at the initial stages of their self-restoration under conditions of varying degrees of conservation were studied. The investigation was carried out in 2017 in Novosibirsk (55°00′ с. ш., 83°04′ в. д.) at the ash dump of CHPP no.5 consisting of two sections - non-reclaimed (S 1) and reclaimed by covering ash and slag with potentially fertile soil (S2). A plot in a birch forest adjacent to the ash dump was used as a control. The collection of material was carried out in the ash dump zones of different degrees of moisture (three plots in both S1 and S2) and in the control (in total, 7 plots). Microarthropod communities included mites (Mesostigmata, Oribatida, Prostigmata) and springtails (Collembola). The microarthropod abundance on the territory of both sections of the ash dump was significantly lower than in the control, while no significant differences were found between the ash dump sections. The influence of reclamation was revealed only for the mites. The representatives of Oribatida appeared to be the most sensitive. There were no significant differences in the proportion of the different groups in the community on S1. On S2 and under control, Oribatida took the lead. Using the example of Oribatida and Mesostigmata model groups, it was shown that the mite communities formed at the ash dump were species-poor and consisted of widely distributed species with a high degree of dominance of some of them. Oribatida appeared to be a good bioindicator for assessing the soil state while restoration succession at ash dumps of CHP plants.

The article presents an analysis of the influence of technogenic pollution on the content of the main groups of biologically active substances (flavonoids, anthocyanins, oxycinnamic acids, procyanidins, tannins, carotenoids, ascorbic and free organic acids) in the fruits and leaves of the representative of the natural flora of Donetsk region Crataegus fallacina Klokov. The content of heavy metals such as cadmium, lead, mercury in the soil (mobile forms) and plant materials was determined, and the environmental safety of the raw materials was evaluated. It was revealed that a significant increase in the content of tannins in the leaves of C. fallacina , as well as a decrease in the content of procynidins in the fruits in anthropogenic conditions, can be recommended for screening the degree of impact of an urbanized environment on plants. The conformity of the raw materials of C. fallacina to the requirements of the regulatory documents for the content of active substances was evaluated. It was shown that this raw material has a high antioxidant activity, which increases in conditions of pollution.

The effect of SO₂ on the oxidative conversion of hydrogen and methane over a wide range of temperatures of 400 ÷ 1 500 ^oC at a pressure of the reacting mixture of 1 atm has been studied by numerical kinetic analysis. The analysis has shown that sulfur dioxide can have both accelerating and inhibitory effects on the oxidative conversion of hydrogen and methane, which is due to the participation of SO₂ and the products of its chemical transformation in conjugated processes. The accelerating effect of SO₂ on the oxidative conversion of hydrogen and methane is observed at low temperatures, and the decelerating effect at elevated temperatures.

New data on parameters of combustion and detonation of two-fuel mixtures of methane and hydrogen with oxygen and air are presented. The data are obtained with variations of both the ration between CH₄ and H₂ and also the ratio between the fuel components and oxidizer. Results for the critical energy of detonation initiation, characteristic size of detonation cells, detonation velocity, and energy release in detonation waves are included. New information on parameters of combustion and detonation of methane mixtures diluted by water, including situations with gas hydrates, is reported.

A CCDS2000 detonator for acetylene, ethylene, propylene, and a multicomponent methylacetylene-allene fraction (MAF) propellant is used to perform experiments on measuring the detonation rate and recording a detonation front cell in a tube 26 mm in diameter and 2 m in length. The experiments are carried out at atmospheric pressure in stoichiometric mixtures diluted by nitrogen to air concentrations and in air-propellant mixtures with a varying propellant content in them. In the case where the explosive mixture components are fed as a flow by stratifying an explosive charge in an initiation zone, a self-sustaining detonation is stably excited up to limiting (spin) regimes. The concentration limits of the detonation existence are determined. In the propellant-air mixtures of acetylene and ethylene, as the values become lower than the limits, there is multifront detonation. For propylene and MAF, a tube diameter of 26 mm is near-critical: only one- and two-headed spin is observed in the entire range of existence. Calculation results are in good agreement with the experiment.

A model of unsteady homogeneous nucleation of boron oxide vapors in chemically reacting gas mixtures is developed. This model is applied to perform a numerical study of homogeneous nucleation of boron oxide vapors in Laval nozzles with different geometric configurations. Typical values of the sizes of boron oxide condensation cores and their concentrations are determined. The potential barrier of nucleation, nucleation rate, and nucleation delay time are estimated. Important qualitative features of homogeneous nucleation evolution along the nozzle are identified. Based on the data obtained, recommendations on model application and its further development are formulated.

Difference in the molar masses of a combustible gas and its combustion products has a strong effect on a flame temperature and a burning rate. Instead of a molar mass difference, one may consider a heat capacity difference at a constant pressure. There are two heat sources in a combustion zone. One of them is chemical, and the other one is similar to heat release (heat absorption) during a first-order phase transition, but, depending on the process, it can be partially chemical. The higher the heat capacity of the fuel in comparison with the heat capacity of the combustion products, the higher the burning rate and the flame temperature. For the physical completeness of the issue under discussion, an ideal thermodynamic cycle is considered, and it is shown that Carnot's formula should contain a correction factor that takes into account a change in heat capacity.

Combustion of mechanically activated mixtures in 2Co-Ti-Al and Co-2Ti-Al is investigated, and alloys based on them are synthesized in self-propagating high-temperature synthesis. Microstructural, X-ray, and differential-thermal studies are performed. A Heusler phase Co₂TiAl-based alloy is obtained for the first time by means of mechanical activation. Conditions for the mechanical activation of a reacting powder mixture for the formation of a single-phase material is experimentally selected.

Dependence of the combustion of a Ti + C granular charge on a granule size is experimentally studied.It is revealed that the burning rate of a granular mixture of all fractions used in the work is higher than the burning rate of a bulk-density powder mixture. It is shown that, with a decrease in the granule size, the burning rate of the charge in the absence of gas decreases due to an increase in the number of boundaries between the granules per unit length of the sample. A strong influence of the nitrogen flow on the burning rate of both large and small granules is established. It is shown that, in contrast to small granules, an increase in the nitrogen flow rate of large granules up to 600 l/h leads to a transition to convective combustion. The studies performed indicate that, despite the structural analogy between mechanically activated and granular mixtures, the relationship between the combustion time and the front transition time in granular mixtures is completely different. This means that the combustion of granular mixtures even in the absence of a gas flow cannot be explained within the framework of a microheterogeneous model.

Influence of micromilling on air conversion of pulverized coal fuel is under study. On the basis of these experiments, computational fluid dynamics methods are used to perform simulation determining the conditions of the process under study. Conversion of coarse coal in a medium of combustion products of fine coal with the following parameters: a flow rate of primary and secondary coal is 0.82; a corresponding air flow rate is 0.35; the excess ratios of primary, secondary, and total air are 0.8, 1.87, and 1.39; temperatures in the active zone are higher than 1 200 ^oC. According to the computational results for this regime, conversion for the primary and secondary coal is 100 % and 60 %, respectively, and the total conversion is »80%. The results obtained suggest that it is possible to increase the efficiency of coal combustion due to micromilling technologies as applied to oil-free ignition and torch illumination systems on steam pulverized coal boilers at TPPs.

An experimental method for determining the limiting pressure perturbations initiating acoustic instability in liquid rocket engine combustors has been developed which can be used to estimate of the stability of the working process. The method involves a statistical processing of the recorded noise pressure pulsations in the vicinity of natural resonance frequencies for all normal modes of acoustic vibrations in cylindrical combustion chambers and gas generators. The vibration damping coefficient (decrement), characterizing the difference between the generated and dissipated energy, is adopted as a diagnostic predictive criterion of the stable or unstable state of a dynamic system. The method is based on the theory of self-oscillating dynamic systems and one-dimensional Markov random processes using the apparatus of the Fokker-Planck-Kolmogorov equation. Analysis of the nonlinear differential equation with a symmetrized stochastic right-hand side describing white noise for experimentally determined amplitudes of pressure pulsations and their statistical processing using Mera software allows the state of the self-oscillating system to be identified a stable or unstable. The method is passive and applicable used without using standard external pulsed disturbing devices.

This paper presents a method and results of an experimental study of the ignition characteristics of samples of high-energy materials by multimode laser radiation. An even distribution of the radiation flux density on the end surface of a cylindrical sample is obtained by its rotation around the axis of symmetry with a given angular velocity. The effect of convective heat transfer of the end surface of the sample with the environment on ignition characteristics is eliminated by placing the sample in a cylindrical container. The results of experiments on ignition of pyroxylin samples by a CO₂ laser with and without rotation rotation of the sample are presented.

Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is extensively employed in military weapons as the main constituent of HMX-based polymer-bonded explosives (PBXs). It is known that the safety of PBXs is closely related to their microstructures. Discontinuities in PBXs, such as micron-sized pores, air bubbles, and interfaces between the explosive crystal and polymer bonds, may transform into hot spots when subjected to impact. Herein, a three-dimensional mechanical-thermal-chemical coupled mesoscopic model is proposed to study the collapse of an air bubble in an HMX crystal under impact. A viscoplastic constitutive model and the Birch-Murnaghan equation of state are employed for the HMX crystal to predict its mechanical response. Thermal decomposition of HMX is taken into account by using multistep thermal decomposition equations. The viscoplastic model yields results that reasonably agree with data obtained in the plane shock experiment. The influence of the edge length of the mesh elements on simulation results is analyzed. Then more simulations are conducted for studying the feasibility of using the viscoplastic model for different orientations of the HMX lattice. Afterwards, the coupled model is applied to study the collapse of an air-bubble/pore in the HMX crystal for different impact velocities.

RDX containing a small amount of single-walled carbon nanotubes is obtained by the method of codeposition from a solution. The detonation of this composition is studied by an electromagnetic method of mass velocity measurement and by a high-resolution electroconductivity method. A clearly expressed chemical spike is observed. Preliminary indications of reaction acceleration in the presence of nanotubes are obtained. The electroconductivity measurements are difficult because of the noticeable conductivity of the original material; if this factor is taken into account, the electrical conductivity profiles behind the detonation front are similar to those observed for pure RDX. Possible reasons for the influence of nanotubes on detonation characteristics are discussed.

The results of a study of the dynamic compression of plastic-bonded PETN by the method of Hopkinson's composite rod (HCR) are presented. The test procedure and some aspects of this method are described. The advantages of the HCR method in comparison with drop weight tests of explosives are briefly discussed. In experiments, the strain rates were 7 500 ÷ 12 000 s^-1. Load-strain and load-displacement diagrams are plotted, and the amount of energy required to initiate an explosive transformation are estimated. It is proposed to use this method as an additional one to the existing methods for studying the characteristics of explosives.

Pipe sticking is one of technical challenges in the drilling industry that has a major impact on the drilling efficiency and well costs. In order to eliminate deep water stuck pipe hazards, a new type of the jet cutter cartridge is designed. The main structure of the cartridge is a linear shaped charge including hydrogen-based emulsion explosives and copper tubes. During the detonation process of emulsion explosives, the copper tubes form several linear jet cutters along the ring direction to penetrate the stuck drill pipe. Experimental results indicate that the properties of hydrogen-based emulsion explosive meet the requirement to the explosive for the environment of the stuck point. This annular jet cutter cartridge is successfully applied in a copper mine to solve a stuck pipe incident.