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Research subject. The pegmatites of Murzinka-Adui region (Ethtern sector of the Middle Urals), represented by three types of veins miarolitic pegmatites with topaz and beryl (mines Mokrusha, Kazennitsa, Semenovskaia), miarolitic rubillite-lepidolite pegmatites (Lipovka veins field) and rare metal pegmatites with Ta-Nb-Be mineralization (deposits Kvartal’noe and Lipovyi Log).Materials and methods. Isotope dating was carried out via the 40Ar-39Ar method by a mass spectrometer Micromass 5400 at the Institute of Geology and Mineralogy SB RAS for mica of different composition (muscovites, biotites and lepidolites).Results. 40Ar/39Ar ages for mica from dated pegmatite veins of the topaz-beryl type coincide within the measurement accuracy: mine Kazennitsa – 252.3 Ma, Mokrusha – 253.7 and Semenovskaia – 250.3 Ma. The average age of the two series of mica from rubillite-lepidolite pegmatites was found to be 254.1 Ma. The average age of four samples of muscovites from rare metal Ta-Nb-Be pegmatites equals 252.6 Ma.Conclusions. The closure of the isotope system of micas in pegmatites of all three studied types (topaz-beryllium, rubillite-lepidolite and rare-metal with Ta-Nb-Be mineralization) occurred almost simultaneously during the timeframe of 254 to 250 Ma years ago. The obtained age values, however, cannot be identified with the time of formation of pegmatites. The analysis of the available data suggests that the closure of the micas K-Ar isotope system of the studied pegmatites as well as previously dated schists and blastomylonites of the Bazhenovo suture zone and granites of the Murzinka-Adui block marks an important episode in the geological history of the eastern margin of the Urals and the basement of the adjacent part of the West Siberian plate: the change of the transpression regime prevailing during the collision stage of the region’s development to the regime of limited postcollision extension.

Interest in embolic myocardial infarction is explained by both the severity of this disease and the complexity of clinical symptomatology, which often causes great diagnostic difficulties. Embolic myocardial infarction with a wide range of various symptoms is always a complication of some other, primary disease of the cardiovascular system, accompanied by the presence of embologic material. Evaluation of individual signs of the underlying disease and the associated complication in the form of an embolic infarction is sometimes very difficult.

The article presents two clinical cases of patients with a fatal outcome after a coronavirus infection. The first patient had sepsis and purulonecrotic phlegmon complication after radiofrequency ablation of the cavatricuspid isthmus. The second one had a complication in the form of the esophageal rupture in the middle third after transesophageal echocardiography. © 2021, NJSC Institute of Cardiological Technology (INCART). All rights reserved.

The rate constants of the interactions of chromium atoms with molecular oxygen through recombination Cr + O2 + M → CrO2 + M (I) and exchange Cr + O2 → CrO + O (II) were determined by a new method for treatment of experimental data. The results, together with the available literature data, led to the following equations for the rate constants of recombination in the low-pressure limit and of the exchange reaction: $${{k}_{{1,0}}}(300 < T < 2000\,\,{\text{K}}) = {\text{ }}3.7{\text{ }} \times {\text{ }}{{10}^{{18}}}{{\left( {{T \mathord{\left/ {\vphantom {T {1000}}} \right. \kern-0em} {1000}}} \right)}^{{ - 1.49}}},$$ cm6 mol–2 s–1, $${{k}_{2}}(700 < T < 4000\,{\text{K}}) = $$ $$4.0 \times {{10}^{{14}}}{{\left( {{T \mathord{\left/ {\vphantom {T {1000}}} \right. \kern-0em} {1000}}} \right)}^{{ - 0.32}}}exp\left( { - {{4480{\kern 1pt} \,{\text{K}}} \mathord{\left/ {\vphantom {{4480{\kern 1pt} \,{\text{K}}} T}} \right. \kern-0em} T}} \right)$$ , cm3 mol‒1 s‒1. An expression for the rate constant of the reverse reaction was obtained from k2(T) and the equilibrium constant for reaction (II): $${{k}_{{ - 2}}}(700 < T < 4000\,{\text{K}}) = 3.6 \times {{10}^{{13}}}{{\left( {{T \mathord{\left/ {\vphantom {T {1000}}} \right. \kern-0em} {1000}}} \right)}^{{ - 0.64}}}$$ cm3 mol‒1 s‒1. Modeling within the framework of the RRKM theory shows that calculation of the rate constant k1,0(T) requires inclusion of not only the ground electronic state of the CrO2 molecule, but also the low-lying excited electronic states up to the dissociation threshold. A comparison of the experimental and calculated temperature dependences shows that the best agreement between them is achieved at an average portion of energy transferred in deactivating collisions of the excited CrO2 molecule with diluent gas molecules of ΔE = 2.8 kJ/mol.

Based on the currently available data, it has been established that the earliest glaciations occurred in the Late Eopleistocene and at the end of the Early Neopleistocene. They had local distribution in the most uplifted parts of the Chersky Range. Their traces are presented in the form of moraines enclosed in sediments of intermontain depressions. Glacial forms of this age have not been identified in the relief of mountains and plains in the North-East of Russia. The Middle Neopleistocene glaciation was the largest, both in area and length of individual glaciers. It was mountain-valley and reticulated; in some areas, mountain-cover. Its time coincides with the stage of activation of the ascending neotectonic movements in the Middle Neopleistocene. Traces of the last two Late Neopleistocene glaciations are well expressed in the relief in widespread exaration, moraine, and fluvioglacial complexes. The first Late Neopleistocene glaciation (Zyryan) was significantly inferior to the one occurred in the Middle Neopleistocene, in all parameters, but it also left large amphitheaters of terminal moraines in the foothill belts. Glacial complexes of the last Late Neopleistocene glaciation are widespread in areas 2-3 times smaller than the previous one and, as a rule, are located within its contours.

During the last 5 years among 48 patients with chronic leukemia, we observed 3 cases of priapism. In all our patients, priapism was initially considered in polyclinics as a manifestation of a local process. In this regard, local treatment was used for a long time in the form of cold lotions and irrigations, novocaine blocks, suppositories, etc. Then, due to the failure of such therapy, the patients were sent to urological clinics, where a more complete study allowed the true nature of the disease. All our patients went through the above path before being admitted to a therapeutic clinic.

Рассмотрены современное состояние и проблемные вопросы создания навигационных карт и баз геоданных. Предложена и апробирована методика создания информационного навигационно-картографического обеспечения для решения задач наземной навигации. Методика проверена путем создания навигационной базы геоданных на тестовый участок по результатам полевого выезда и камеральной обработки. Определены перспективные направления дальнейшего развития методики за счет использования межобъектных топологических отношений.

One of the main scientific and practical problems in the Arctic is the study of the dynamic state of the sea ice cover. The main parameters in the general model of drifting ice are the drift velocity vector, friction stress at the air-ice and ice-water interfaces, and the forces of dynamic interaction of ice fields. Establishing the connection between the large-scale processes in the atmosphere-ice-ocean system is necessary for developing methods of forecasting ice compression and ridging and the formation of local and extended fractures and leads, which help improve the existing climate models. The main aim is to obtain results of full-scale instrumental measurements of parameters of ice large-scale mechanics and dynamics, which provide a physical basis for explaining the nature of observed large-scale ice processes and allow one to perform physical parametrization. To accomplish this aim and evaluate the physicomechanical condition of the drifting ice cover of the Arctic Ocean, the “Transarktika-2019” expedition performed a real-time ice monitoring in April 2019. The investigation was conducted using seismometers and tiltmeters installed on the ice such that they formed a triangle with the sides measuring up to two kilometers. Data has been obtained on the wave and oscillation processes of crack formation, compression and ridging of ice. The possibilities of deciphering the initial data on the physics of wave and oscillatory processes in the icewater system considerably increase when using the known methods of processing seismic signals. With use of spectral Fourier analysis wavelet-transformation of oscillations significanlty extending possibilities of the seismic method at revelation of prognostic signs of crack formation and compression was applied. It is shown that the dynamics of ice processes can be connected with oceanic swell and tidal events. A possibility is created for obtaining new results in the investigation of large-scale mechanics of sea ice.

The Lipovka and Alabashka ruby occurrences in the Central Urals hosted in marble of the Murzinka–Adui Anticlinorium are considered. The field works were carried out; the chemical compositions of rocks and minerals and oxygen isotopic composition of corundum and silicates were determined; and micas were dated by the K–Ar method. These occurrences are similar in geological environment and mineral assemblages to the ruby occurrences in the South Urals and deposits in Southeast Asia. At the Alabashka occurrence, ruby was also found from brecciated mineralized granite and amphibolite. The mineralized breccia and ruby-bearing marble are enriched in K- and Cr-bearing minerals. Ruby characterized by a narrow range of the oxygen isotopic composition (δ18О = 14.2–17.8‰) corresponding to that of metamorphic and metasomatic corundum. The hydrogen isotopic composition of fuchsite ranges from –78.5 to –89.6‰, while the δD value calculated for fluid equilibrated with fuchsite varies from –48.8 to –79.7‰ that is consistent with the high-temperature equilibrium with magmatic rocks. Aluminum and Cr were mobile elements and could be inflowed by fluids during ruby formation. Corundum mineralization at both occurrenceswas dated at 280–260 Ma, which is consistent with the beginning of post-collisional relaxation. The Murzinka–Adui Anticlinorium is the most prospective area in the Urals for the high-quality ruby deposits.

Research subject. The article presents the results of dating two dolerite dikes differing in geochemical features from a section along the Iset river in the area of Smolinskoe settlement (the Eastern zone of the Middle Urals). Materials and methods. The dating was performed by an U-Pb ID-TIMS technique for single zircon grains using an artificial 205Pb/235U tracer in the laboratory of geochronology and isotope geochemistry of the Geological Institute of the Kola Science Centre of the Russian Academy of Sciences. The lead isotopic composition and uranium and lead concentrations were measured using a Finnigan-MAT (RPQ) seven-channel mass spectrometer in dynamic mode using a secondary electron multiplier and RPQ quadrupole in ion counting mode. Results. The dikes were dated 330 ± 3 Ma and 240 ± 2 Ma. Conclusions. The research results indicate different ages of dolerite dikes developed within the Eastern zone of the Middle Urals. The oldest of the two established age levels corresponds to the Early Carboniferous era. This fact, along with the proximity of the dolerites to the petrochemical features of the basaltoids of the Early Carboniferous Beklenischevsky volcanic complex, allows these bodies to be considered as hypabyssal comagmates of these volcanics. The youngest obtained age level – Triassic – indicates that the introduction of some dolerite dikes was associated with the final phases of the trapp formation developed rarely within the eastern outskirts of the Urals and widely further east in the foundation (pre-Jurassic basement) of the West-Siberian Plate.

The 40Ar–39Ar dating of mica from schists and blastomylonites, sampled within the limits of a fault that separates the Eastern zone of the Middle Urals, sinking beneath the sedimentary cover of the West Siberian Plate, from the structures located to the west of this plate, in the exposed part of the Urals, has shown that the final phase of deformations was represented by sinistral strike-slip faults trending submeridionally with an age of 251 Ma. The deformations studied virtually exactly coincide in time with the formation of submeridionally oriented grabens in the basement of the West Siberian Plate.

Comparative results of experiments aimed at studying the evolution of dust-laden jets induced by the presence of structural elements and grooves on the surface of loaded specimens are reported. The results are obtained with the use of pulsed X-ray diffraction radiography and synchrotron radiation. Information on dust density changes in synchrotron diagnostics is obtained by using multiframe filming. In the case of single-frame recording by means of pulsed X-ray diffraction radiography, a glancing detonation wave was used for studying the dust behavior instead of the normal wave.

Research subject. This article presents data on the nature of rock deformations in the Bazhenov suture zone. The data was obtained by 40Ar/39Ar dating of mica samples from schists and blastomylonites, which were collected acrossan area extending approximately for 100 km along the Bazhenov suture. This suture separates the Eastern zone of the Middle Urals dipped under the cover of the West Siberian plate from exposed geologic structures of the Urals.Methods.The character of the deformations was studied by means of direct geological observation. The age of the deformations was determined by mica dating using the 40Ar/39Ar method.Results. The deformations were found to have occurred in several phases. The initial phase, which led to the formation of a band of blastomylonites and rocks showing a varying degree of schistosity with a width of over 10 km in particular areas, is likely to have had the character of left-lateral fault. The upper age limit of this deformation phase is determined by the intrusion of the subalkaline rocks of the Petukhovskii complex (280 Ma), which had not been affected by any deformation processes. The subsequent type of deformations had been left-lateral strike-slip faults of submeridianal strike and subvertical dip, which were represented by low-thickness (usually about 10 cm, rarely up to 0.5 m) zones of intensely deformed rocks cutting the schistosity of the previous phase at an acute angle. The final phase of the deformations is shown to be a sloping fault. The dislocation planes of this type were represented by slickensides and chlorite incrustations. Despite the apparent polychronicity of the deformation processes, which were established within the Bazhenov suture zone by our geological observations, 40Ar/39Ar age dating identified only one event. The average value of five conducted tests was about 251 Ma. Apparently, this age should be associated with the most recent geological processes having occurred at temperatures sufficient to fully overload the K-Ar isotopic system of the studied rocks, such as the deformations caused by strike-slip dislocations.Conclusions. The strike-slip fault dislocations dated in this work occurred approximately 25 Ma after the completion of the tectonic activity in the Serov-Mauk fault zone, which is located to the west of the Bazhenov zone. In addition, the time of these dislocations very nearly coincides with that of the formation of the grabens of meridional strike at the base of the West Siberian plate, which took place about 250 Ma ago. This supports apreviously made conclusionon the similar character of the geological development of the eastern border part of the Urals and the adjoining basement of the West Siberian plate.

The glacial and slope morphosculpture and correlated deposits of the Late Pleistocene and Holocene in the northeastern part of the Kilgan Mountains (Okhotsk–Kolyma region) were studied. The general three-element structure of loose cover in the glacial valley of Engteri Creek was established: moraine occurs in the lower part; proluvial deposits, in the middle; and covering deluvial deposits, on top. The sequence of postglacial evolution of slope processes was revealed. In the Atlantic (7245–5895 years ago), proluvial flows were the most active: they reached far beyond the slopes and covered moraine. Later, in the Subboreal, surface erosion intensified. The sedimentation rates in Dzhul’etta Lake were calculated. The glacial peak revealed in bottom sediments falls into the period of 19 410–13 880 years ago, with the smallest sedimentation rate, 6.3 cm/1000 years, which is lower compared to the underlying and overlying layers by a factor of two to three.

The work presents the K–Ar isotope age (54–65 Ma) and isotope–geochemical composition of the post-subduction volcanics which compose the basalt nappes in the Bolshaya Garmanda River valley (North Okhotsk Region). It is established that the age of the Garmanda volcanics differs from that of the rocks of the Kytyima Formation, in the composition of which these volcanics were earlier studied. The isotope contents of Sr and Nd and low concentrations of heavy rare earth elements (HREE) relative to the MORB composition indicate the moderately depleted composition of the mantle source. The enrichment of the volcanics with large-ion lithophilic elements (LILE) can be explained by the role of fluids captured by the melts in the course of melting of the continental crust transformed as a result of the subduction metasomatism.

This paper reports Rb–Sr and Sm–Nd isotope data on the gabbro–diorite–tonalite rock association of the Reft massif (eastern margin of the Middle Urals) and Lu–Hf isotope data on zircon populations from these rocks. In terms of Nd and Hf isotope composition, the rocks of the studied association are subdivided into two distinctly different groups. The first group consists of gabbros and diorites, as well as plagioclase granites from thin dikes and veins cutting across the gabbros. In terms of 43Nd/144Nd i = 0.512518–0.512573 (eNd(T) = +8.6...+9.7) and 176Hf/177Hf i = 0.282961–0.283019 (eHf(T) = +15.9...+17.9), these rocks are practically identical to depleted mantle. Their Nd and Hf model ages show wide variations, but in general are close to their crystallization time. The second group is represented by tonalites and quartz diorites, which compose a large body occupying over half of the massif area. These rocks are characterized by the lower values of 143Nd/144Nd i = 0.512265–0.512388 (eNd(T) = +3.7...+6.0) and 176Hf/177Hf i = 0.282826–0.282870 (eHf(T) = +11.1...+12.7). The TDM values of the second group are much (two–three times) higher than their geological age (crystallization time), which indicates sufficiently long crustal residence time of their source. The initial 87Sr/86Sr in the rocks of both the groups varies from 0.70348 to 0.70495. This is likely explained by the different saturation of melts with fluid enriched in radiogenic Sr. The source of this fluid could be seawater that was buried in a subduction zone with oceanic sediments and released during slab dehydration. Obtained data make it possible to conclude that the formation of the studied gabbro–diorite–tonalite association is a result of spatially and temporally close magma formation processes in the crust and mantle, with insignificant contribution of differentiation of mantle basite magma.

The structure of a large paleoseismodislocation located on the southeastern flank of the Cherskii seismic belt, in the upper reaches of the Ola River, 125 km NNE of Magadan, is studied. Detailed morphologic, morphometric, and structural descriptions of this paleoseismodislocation are made. The main parameters of the landslide body and the dammed lake formed by it are determined. The correlating deposits formed in the dammed lake and upon the surface of rupture are studied, and their radiocarbon age is determined.

An experimental and computational study of the formation of pure iron nanoparticles, carbon nanoparticles (soot), and binary carbon-coated iron nanoparticles during the pyrolysis of iron pentacarbonyl–argon, ethylene–argon, and iron pentacarbonyl–ethylene–argon mixtures, respectively, behind reflected shock waves is carried out. The shape and size distribution of these nanoparticles are examined on a Zeiss Ultra plus ultrahigh-resolution field-emission scanning electron microscope. The binary iron–carbon particles were also investigated by high-resolution transmission electron microscopy and high-angle annular dark-field imaging (HAADF STEM) on a FEI Osiris transmission electron microscope equipped with a Bruker SuperX detector. Detailed kinetic simulations of the formation of these three types of particles are performed, which predict the concentration, average size, and size distribution of particles.

Chemical ionization of n-hexane, methane, and acetylene is experimentally studied behind reflected shock waves over a wide temperature range at nearly atmospheric pressure and simulated within the ...

U–Pb LA ICP–MS dating of zircon from rocks of the Nekrasov gabbro–granitoid complex within the eastern margin of the Middle Urals was performed. The average U–Pb age calculated from three concordant measurements (326 ± 8 Ma) shows that their intrusion occurred at the Serpukhov Stage of the Early Carboniferous. According to the ideas on periodization of magmatic processes within the eastern sector of the Middle Urals, the formation of this complex corresponds to the final episodes of the continental marginal (supersubduction) magmatism.

According to isotopic analysis of rocks of the Reft gabbro–diorite–tonalite complex (Middle Urals), gabbro and related diorite and dikes and vein-shaped bodies of plagiogranitoids, crosscutting gabbro, are similar to the depleted mantle substance in eNd(T) = 8.6–9.7 and eHf(T) = 15.9–17.9. Their model Hf ages are correlated with the time of crystallization. Here, the tonalites and quartz diorites constituting most of the Reft massif are characterized by lower values: eNd(T) = 3.7–6.0, eHf(T) = 11.1–12.7, and T DM values significantly exceeding the age datings. This is evidence that Neoproterozoic crustal rocks were a source of parental magma for these rocks. The primary 87Sr/86Sr ratio in rocks of both groups is highly variable (0.70348–0.70495). The data obtained allow us to reach the conclusion that the Reft gabbro–diorite–tonalite complex was formed as a result of nearly synchronous processes occurring in the crust and the mantle within a limited area.

The Upper Kolyma gold placers of northeastern Russia produced 2,700 metric tons (t) Au. Approximately 40% of this gold was extracted from just five placers, Chai-Yuria, Berelekh, Maldyak, Malyi At-Yuryakh, and Omchak, and their immediate tributaries. The placers were derived from Late Jurassic to Early Cretaceous lode deposits, formed during sinistral translation subsequent to the Kolyma-Omolon superterrane accretion to the Verkhoyansk passive margin of the Siberian craton. The metallogenic events produced either abundant and widespread small quartz veins or more localized large to superlarge quartz stockworks and disseminated gold deposits. These orogenic gold deposits acted as a principal hard-rock source during formation of the gold placers, beginning in the Late Cretaceous but most importantly during the Cenozoic. Tectonic, geomorphologic, and climatic factors at a triple junction of the North American, Eurasian, and Okhotsk lithospheric plates provided the ultimate controls on placer formation.

The Lu–Hf isotope systematics of zircon from the gabbro–plagiogranite association (gabbro, diorite, tonalite, and plagiogranite), which is one of the most typical associations of igneous rocks in the Urals, was studied for the first time. The isotope study yielded a unified age limit of 433 Ma, which corresponds to the time of formation of this rock association. The younger “rejuvenated” ages characterize superimposed thermal impact events, induced by the volcanic arc activity, as well as collisional and postcollisional processes. Here, the initial 176Hf/177Hf(t) ratio in the studied zircon from gabbro and plagiogranite corresponds in fact to a highly LILE-depleted (DM) mantle.

The authors provide paleontological and mineralogical description of the finding of the brachiopod of Atrypinae gen. et sp. indet. of the Silurian (Llandovery) – Late Devonian (Frasnian) age in a well-formed garnet-almandine crystal. Field geologist D. L. Suslov was the one who found the brachiopod in high-aluminous gneisses in Verkholovsky garnet mine, which is a part of the Evgenie-Maximilianovsky (Palkinsky) mineral mines located in the southeastern part of the Verkhisetsky granite batholite, on the territory of the historical-landscape park "Istoki Iseti". The Verkholovsky garnet mine is located on the southern slope of Pup Mountain, about 6 km west of Ekaterinburg city, on the eastern slope of the Middle Urals. The stock of the Ural Geological Museum stores the sample containing the brachiopod imprint, its measures are 3 × 2.2 × 1.6 cm and it looks like a parallel aggregate of several garnet-almandine crystals. Main habitus forms of the garnet individuals are rhombododecahedron d{110} and tetragontrioctahedron n{211}, the latter forming thin facets of the rhombododecahedron edges. The shell imprint is not in the garnet crystals, but in the base of the sample, among the fine-grained light-brown mass, whose thickness is not more than 2–3 mm. The fine-grained mass previously probably was a carbonate matrix of the brachiopod, and during the growth of the garnet at the border of two heterogeneous media (carbonate and silicate), a local metasomatic process of substituting the garnet aggregate for the primary (carbonate) substance manifested. The article also contains a brief geological sketch of the place of the finding and an overview of information about other similar findings. Chemical U-Th-Pb-dating allowed to determine the age of monazite inclusions in garnet (344 million years).

U–Pb (SIMS) dating of zircons from granite of the Petrokamensk gabbro–granitoid complex, marking termination of the Devonian island–arc magmatism in the Verkhisetsk–Tura Zone of the Middle Urals, gave an age of 386 ± 3 Ma. Zircons from the West Verkhisetsk granitoids, the formation of which corresponds to the beginning stage of magmatism of the continental margin in the region, yielded ages of 386.6 ± 4.1 and 381.8 ± 6.0 Ma. This suggests that the change in the regime of the island–arc geodynamic mode to an active continental margin took place at the boundary of the Middle and Late Devonian. The upper boundary of existence of the continental margin subduction zone is determined by the closure of the Ural paleo-ocean and the beginning of continental collision processes, which resulted in accumulation of flysch in the Ural foreland trough from the second half of the Bashkirian Stage.

The ignition of a stoichiometric ethylene−oxygen mixture diluted with argon was experimentally and computationally studied to gain new insights into the nature of the chemiluminescence that accompa...

The results of detailed kinetic simulations of the formation of soot particles in the pyrolysis of n-hexane–argon mixtures and in the oxidation of fuel-rich (φ = 5) n-heptane–oxygen–argon mixtures behind reflected shock waves at pressures of 20–100 bar and a constant concentration of carbon atoms or a constant fraction of argon in the initial mixture within the framework of a modified reaction mechanism are reported. The choice of n-hexane and n-heptane for examining the effect of pressure on the process of soot formation was motivated by the availability for these hydrocarbons of experimental measurements in reflected shock waves at high pressures (up to ~100 bar). The temperature dependences of the yield of soot particles formed in the pyrolysis of n-hexane are found to be very weakly dependent on pressure and slightly shifting to lower temperatures with increasing pressure. In general, pressure produces a very weak effect on the soot formation in the pyrolysis of n-hexane. The effect of pressure and concentration of carbon atoms in the initial mixture on the process of soot formation during the oxidation of fuel-rich n-heptane mixtures behind reflected shock waves is studied. The results of our kinetic simulations show that, for both the pyrolysis of n-hexane and the oxidation of fuel-rich n-heptane–oxygen mixtures, the influence of pressure on the process of soot formation is negligible. By contrast, the concentration of carbon atoms in the initial reaction mixture produces a much more pronounced effect.

The chemiluminescent emission from CH*, C*2, OH*, and CO*2 during the self-ignition of various mixtures of ethane with oxygen and argon behind reflected shock waves in the 1240–1790 K temperature range at a total concentration of the mixture М 5 = (1 ± 0.2) × 10−5 mol/cm3 is experimentally studied. It has been shown that the time-to-maximum in the emission intensity profiles is almost identical for all the emitters studied. How the pattern of the OH* emission profile changes with the temperature and mixture composition is examined. The CH* and C*2 emission profiles demonstrate virtually symbatic behavior in the covered ranges of temperature, pressure, and equivalence ratio. It is established that the emission signals from OH* and CO*2 appear earlier than the C*2 and CH* emission signals. The numerical simulation predictions are found to be in close agreement with the experimental results.

Chemical ionization during the oxidation of methane and acetylene is experimentally and theoretically studied behind reflected shock waves over a wide temperature range and atmospheric pressure. The results of experimental measurements of the concentration of free electrons by microwave interferometry and electric probe method during the oxidation of acetylene and methane behind reflected shock waves are presented. A detailed kinetic model of the process of chemical ionization was developed. The results of experimental measurements and kinetic simulations are in good qualitative and quantitative agreement. The kinetic model of chemical ionization makes it possible to improve the kinetic description of the experimentally measured time histories of free electrons for the hydrocarbons studied.

The formation of soot particles in the pyrolysis and oxidation of various aromatic and aliphatic hydrocarbons in argon behind reflected shock waves has been investigated by computational and theoretical methods. The hydrocarbons examined include methane, ethane, propane (aliphatic hydrocarbons with ordinary bonds), acetylene, ethylene, propylene (aliphatic hydrocarbons with multiple bonds), benzene, toluene, and ethylbenzene (simplest aromatic hydrocarbons). Soot formation in the pyrolysis and oxidation of both aromatic and aliphatic hydrocarbons can be simulated in detail within a unified kinetic model. The predictive power of the unified kinetic model has been verified by directly comparing the calculated kinetic data for the formation of products and reactive radicals in the pyrolysis and oxidation of various hydrocarbons to the corresponding experimental data. In all calculations, all the kinetic parameters of the unified kinetic model were strictly fixed. A good quantitative fit between the data calculated via the unified kinetic model and experimental data has been attained.

Experiments on pyrolysis and oxidation of rich mixtures of various aliphatic and simple aromatic hydrocarbons in reflected shock waves have been performed. The mixtures C2H2/Ar, C2H6/Ar, C2H4/Ar, C2H4/O2/Ar, CH4/Ar, CH4/O2/Ar, C3H8/Ar, C3H6/Ar, toluene/Ar, and benzene/Ar were studied. The yield of soot and the temperature of soot particles were determined experimentally by the double-beam absorption emission method. The kinetic model of soot formation during the pyrolysis and oxidation of rich mixtures of aliphatic and aromatic hydrocarbons complemented with a set of nucleations of soot particles from both polyaromatic fragments and unsaturated aliphatic hydrocarbons was suggested. This kinetic model of soot formation was successfully tested. It describes the experimental literature data on the yield of the products of pyrolysis and oxidation of acetylene and diacetylene in a shock tube. The results of our experiments and kinetic calculations of the time, temperature, and concentration dependences are in good agreement for all hydrocarbons under study. All the kinetic parameters of the model remained strictly constant.

A noise model in which fluctuation noise of output current is determined by weakly emitting fragments of thermionic cathode working in the saturation regime (defects on the emitting surface) is proposed. The measured noise characteristics of the shot and flicker components of noise can be used to determine distribution of defects with respect to emission current densities and the noise parameters of defects. The relation of noise parameters and the degree of degradation of cathode is analyzed using the pulsed emission current at relatively long working times of dispenser cathodes with the W–Re sponge and Os coating. Preliminary results show that that proposed noise parameters can be used for the development of working methods for estimation of cathode quality.

The U–Pb (SHRIMP) dating of zircon from the layered complex of ophiolitic gabbro in the Klyuchevsk massif yielded an age of 456 ± 6 Ma corresponding within the limits of error to zircon dates obtained for other petrographic varieties from this massif. The investigation of the composition of silicate inclusions in dated zircon grains revealed that they are represented by typical metamorphic minerals: albite, zoisite, and secondary amphiboles. The data indicate that zircon was crystallized during metamorphic transformations of gabbroids and its U–Pb age (Late Ordovician–Silurian) is characteristic of all rocks in the ophiolite association of the Klyuchevsk massif indicating the age of metamorphism, not their formation time.

The initiation of the autoignition of hydrogen–oxygen–argon mixtures behind reflected shock waves is studied by absorption and emission spectrophotometry in the temperature range of 960 < T < 1670 K at pressures of ~0.1 MPa. Introduction of Mo(CO)6 additive in an amount of ~80 ppm made it possible to study the effect of O atoms on the shortening of the ignition delay time of H2–O2–Ar mixtures. A kinetic modeling of our own and published experimental data at temperatures of 930 < T < 2500 K and pressures of 0.05 < P < 8.7 MPa enabled to establish how the initiation reactions influence the process of self-ignition and to evaluate the rate constant for one of the initiation reactions: k(H2 + O2 → 2OH) = (3 ± 1) × 1011exp(–E a/RT), cm3 mol–1 s–1, where E a = (40 ± 2) kcal/mol.

The analysis of the Sr and Nd isotopic composition in different granitoids of the Verkhisetsk, Shartash, Krasnopolsk, Petrokamensk, and Shabry massifs, which were successively formed in the island arc, continental marginal, and collisional geodynamic settings during the period from the Middle Devonian to the early Permian, revealed that 87Sr/86Sr0 values in them vary from 0.70331 to 0.70431 and eNd(t), from +1.9 to +6.2. The two-stage model Nd age of granitoids (938–629 Ma) indicates that their magma originates from material at least Neoproterozoic in age, not younger. The observed variations in the Nd model ages of granitoids and 87Sr/86Sr0 values provide grounds for assuming the primary heterogeneity of the source of granitoid melts.

Chemical ionization is the process of formation of charged particles as a result of energy release during the formation of chemical bonds in chemical reactions between neutral components. Chemical ionization is most often observed in the processes of hydrocarbon combustion. Measurements of ionization current in internal combustion engines are of great practical interest. Most experiments on chemical ionization were carried out in flames with obvious limitations: the composition of the mixture cannot be changed in an arbitrarily wide range of concentrations of fuel and oxidant, to investigate the pyrolysis processes, to arbitrarily change the temperature and pressure, it is impossible to dispose of the transfer processes and gradients of temperature and reactive components. Experiments in shock tubes in the reflected shock waves are free of all of the above disadvantages. In the present work, electric currents to the electrically insulated and uninsulated cylindrical probes were recorded, to which a negative (−9V) or positive (+9V) potentials were applied. In these experiments, the displacement and the total currents were recorded respectively. In the same experiments, the signals of chemiluminescent emission of electronically excited OH* radicals (λ = 308 nm) were simultaneously recorded. The main goal of the present work was to measure experimentally (1) the displacement currents on positive and negative probes, (2) the total and displacement currents on a negative cylindrical probe during acetylene pyrolysis and oxidation, and (3) to confirm correlation of the displacement currents and the signals of chemiluminescent emission of electronically excited OH* radicals.

The self-ignition of a number of near-stoichiometric acetylene−oxygen mixtures diluted with argon are experimentally and computationally studied to gain additional insights into the nature of the chemiluminescence that accompanies this process and to obtain some of its quantitative characteristics. The experiments are performed behind reflected shock waves at temperatures of 1270–1820 K and a pressure of ∼1 bar. The time evolution of the intensity of the luminescence of the electronically excited C2*, CH*, and OH* radicals and CO2* molecule is concurrently monitored. The measured temperature dependences of the ignition delay time are demonstrated to be in satisfactory agreement with the published data and the results of simulations within the framework of our own and a number of published mechanisms. To achieve a better description of the behavior of CO2* and C2*, and to improve the agreement between the experimental data and the results of kinetic simulation of CO2*, a novel kinetic mechanism wherein the reaction СН2 + О2 = СО2* + Н + Н is replaced by the reaction СН + О2 = СО2* + Н has been proposed.

Experimental and computational studies of soot formation during the pyrolysis and oxidative pyrolysis of hydrocarbons with multiple bonds have been performed on ethylene and acetylene as examples. The experiments have been carried out behind reflected shock waves over the temperature range from 1700 to 2800 K at a pressure of 3 to 5 bar. The process of soot formation was recorded using the absorption-emission method, which enables one to simultaneously measure the mass of soot particles per unit volume and their temperature. The experimental data are interpreted within a new kinetic mechanism that takes into account the nucleation of soot particles from both polyaromatic hydrocarbon fragments and unsaturated aliphatic hydrocarbons. The proposed kinetic model of soot formation closely reproduces the time dependence of the soot yield and the temperature of soot particles measured in the present work, as well as the concentrations of several key components formed in the early stages of pyrolysis and oxidation of acetylene and ethylene, reported in a number of works by other authors.

The U-Pb SIMS age dating of zircons from different-age granitoid assemblages varying in composition of the Verkhisetsk batholith shows that it comprises rocks of three age groups, formed at different stages of the Ural Mobile Belt. The first age group is represented by quartz diorites (396 ± 5 Ma) with insignificant distribution in area. Their formation was synchronous to island arc volcanism, manifested in the area of study from the second half of the Emsian to late Givetian-early Frasnian. According to this, we could consider these granitoides as comagmatic to island arc volcanites. The second age group includes tonalites and trondhjemites (367 ± 4 Ma), comprising the western part of the batholith. On the basis of similarity between these rocks and granitoides of modern active continental margins in material composition, it is assumed that they formed throughout the island arc-continental stage of development of the Ural Mobile Belt. Granitoides of the third age group, dominating in the Verkhisetsk batholith, formed as a result of several homodrome rhythms of granodiorite-granite intrusions of moderate-potassium composition during a short period of time (315–300 Ma). Their formation is related to the initial stage of the collision stage of development of the region, lasting from the early Bashkirian to Late Permian in the Middle Urals, which is fixed by deposition of flysch and molasse sediments in the Ural Foredeep. The data obtained change our understanding significantly of the character of evolution of granitoid magmatism and the place of rock assemblages studied in the geological history of the Urals.