Home – Home – Jornals – Region: Economics and Sociology 2021 number 2

This study presents an overview of the systematic petrography, mineralogy, and geochemistry of jadeitite and jadeite-rich rocks found as blocks in the serpentinite mélanges of the Rio San Juan Complex (RSJC) of the northern Dominican Republic. The RSJC is one of the remnants of the subduction/accretionary complex of the Great Caribbean Arc that once spanned the gap between North and South America, moved relatively eastward to its present position as the Lesser Antilles island arc, and left collisional fragments along the two continental margins. Our systematic collection of heterogeneous samples ranges from jadeitite s.str. (sensu stricto) with ≥90 vol.% jadeite to quartz-rich rocks with jadeite and lawsonite. Two suites of rock types can be recognized. In the matrix-quartz-free rock suite, albite is the principal vein-filling or interstitial phase. Quartz is present only as inclusions in the cores of some jadeite crystals. In the matrix-quartz-bearing rock suite, quartz is abundant and albite is relatively rare. The first-order question concerning jadeite-rich rocks is whether jadeite precipitated from a high-pressure aqueous fluid (“vein precipitation” or “P-type”) or whether the jadeite-rich rock formed through comprehensive metasomatic replacement of an igneous protolith (“R-type”). Some examples occur as discordant veins and are clearly P-type. For most, however, classification has been equivocal. The systematic data on the petrography and whole-rock chemistry of jadeite rocks from the RSJC presented in this paper leads to significant clarification. A major argument against R-type genesis is that the metasomatic mass transfer required to produce jadeitite and jadeite-rich rocks from any normal igneous protolith is prohibitively complex. Using whole-rock and major-element compositions, we show that many members of the matrix-quartz-bearing rock suite from the RSJC can be derived by isochemical HP/LT metamorphism of normal oceanic plagiogranites subducted together with oceanic crust. Isocon analysis shows, furthermore, that more jadeite-rich rock types and also members of the matrix-quartz-free suite can be derived from such plagiogranites primarily by straightforward desilication, a realistic scenario in a serpentine-rich environment. The quartz inclusions found in jadeite crystals of the matrix-quartz-free suite corroborate a genetic path in which the plagioclase in a plagiogranite protolith reacts to jadeite + quartz. Later desilication and the formation of albite in the Si-undersaturated rock matrix leave tell-tale quartz inclusions as relics in jadeite crystals.

The Belomorian Province (BP) of the Fennoscandian Shield is a high-grade metamorphic belt composed of Meso- to Neoarchean tonalite-trondhjemite-granodiorite (TTG) gneisses with subordinate supracrustal complexes. The Belomorian crust is underlined by a thick mantle keel, a structural element typical of Archean cratons. Belomorian rocks were metamorphosed under conditions of mainly high-pressure amphibolite to granulite facies in the both Archean and Paleoproterozoic times. The TTG gneisses contain numerous blocks of almost completely retrogressed eclogite (eclogite-1). This paragenetic association of eclogite-1 and gneisses can be classified as an Archean eclogite-TTG gneiss mélange, a component of the Belomorian continental crust produced by subductional, accretionary, and collisional processes of the Belomorian collisional orogeny 2.9-2.66 Ga ago. The Paleoproterozoic history of the BP comprises two prominent tectonic periods: (i) early Paleoproterozoic (~2.5-2.4 Ga), related to a superplume, and (ii) late Paleoproterozoic (2.0-1.85 Ga), resulted from crustal reworking during the Lapland-Kola collisional orogeny that produced strong penetrative metamorphic and local deformational overprint. The Paleoproterozoic highest-grade metamorphic overprint is represented by patches of eclogites (eclogite-2) in Paleoproterozoic mafic dikes and eclogite-1. Field relations between eclogite-1 and eclogite-2 are described in the Gridino area of the western coast of the White Sea. So, the BP is a high-grade polymetamorphic belt formed by a superposition of the Neoarchean Belomorian and Paleoproterozoic Lapland-Kola orogenies, whose characteristic features are eclogites produced by subduction and collision.

The isotope-geochemical features of diamondiferous metamorphic rocks of the Kokchetav subduction-collision zone (KSCZ) show that both the basement rocks and the sediments of the Kokchetav massif were their protoliths. A whole-rock Sm-Nd isochron from the diamondiferous calc-silicate and garnet-pyroxene rocks and migmatized granite-gneisses of the western block of the KSCZ yielded an age of 1116 ± 14 Ma, while an age of 1.2-1.1 Ga was obtained by U-Pb dating of zircons from the granite-gneiss basement of the Kokchetav microcontinent. Based on these data, we assume that the protoliths of the calc-silicate and garnet-pyroxene rocks and the granite-gneisses of the KSCZ were the basement rocks sharing an initially single Nd source, which was not influenced by high- to ultrahigh-pressure metamorphism (~530 Ma). Therefore, their geochemical features are probably not directly related to ultrahigh-pressure metamorphism. The corresponding rock associations lack isotope-geochemical evidence of partial melting that would occur during ultrahigh-pressure metamorphism, which suggests that they were metamorphosed under granulite facies conditions. At the same time, the high-alumina diamondiferous rocks of the Barchi area (garnet-kyanite-mica schists and granofelses), which were depleted to different degrees in light rare-earth elements (REE) and K, have yielded a Sm-Nd whole-rock isochron age of 507 ± 10 Ma indicating partial melting of these rocks during their exhumation. The close ɛ_Nd(1100) values of the basement rocks and garnet-kyanite-mica schist with geochemical characteristics arguing against its depletion during high-pressure metamorphism indicate that the basement rocks were a crustal source for high-alumina sediments.

The paper presents new data on the Rauer Islands, one of the unique objects of the East Antarctic Shield. The interest in this area is triggered by its complex geologic structure, including both Archean and Proterozoic fragments of the Earth’s crust, and by its multiphase formation. A detailed scheme of the geologic structure of the area is proposed, new petrologic complexes are revealed, and the stages of tectonomagmatic activity at ~1400-1320 Ma and 1150 Ma are reliably dated. This serves as a factual basis for comparison of the study area with other regions of East Antarctica. Based on the geological and isotope data obtained, the Meso-Neoproterozoic Filla Terrane in the area of the Rauer Islands is recognized. It is composed of metamorphic and primarily intrusive rocks, whose protoliths formed in the time interval 1400-950 Ma. Three periods of tectonothermal activity have been established in the Filla Terrane: Mid-Mesoproterozoic (1400-1320 Ma), Meso-Neoproterozoic (1150-886 Ma), and early Cambrian (536-504 Ma). The first period is the formation time of Mesoproterozoic crust, and it is time-correlated with the tectonogenesis phase in the adjacent Rayner province. The second period corresponds to the later phase of tectonothermal activity in the Rayner province. In the Filla Terrane, this period can be divided into two intervals, 1150-1100 Ma and 1010-886 Ma. The former interval is treated as intense crustal growth in the course of granitoid and mantle magmatism. The latter interval is a period of tectonothermal processes accompanied by intense deformations, high-temperature metamorphism, and intrusion of porphyritic granitoids. Apparently, the gap between the first and the second intervals is the time of deposition of the sedimentary protolith of paragneisses, which, together with the surrounding rocks, underwent high-temperature metamorphism and deformations at 950-914 Ma. The synchronous evolution of the Archean block and the Filla Terrane began at least within 1100-1000 Ma. The youngest, early Cambrian, period of tectonic activity coincides with the development of local low-temperature mylonite zones and the intrusion of synkinematic pegmatite veins. Thus, the tectonothermal evolution of the Filla Terrane includes almost the same main phases of crustal growth and transformation as the Rayner province. This indicates that the Filla Terrane is a fragment of the Rayner province, which accreted to the Archean terrane at least in the late Mesoproterozoic.

The structure of the initial and predicted oil resources of the West Siberian petroleum province is quantitatively assessed. The assessment is based on the law of mass distribution of hydrocarbon accumulations, i.e., the truncated Pareto distribution and simulation modeling of the general set of oil fields. This approach makes it possible to estimate the amount of oil and the total oil resources concentrated in intervals of any size, in particular, in intervals of small and fine fields, in order to determine the economic efficiency of their development. The considered estimates do not apply to unconventional resources, such as the shale oil of the Bazhenov Formation.

We present the preliminary results of a study of the Bystrinskoe earthquake, which occurred in the southern Baikal region on 21 September 2020 and was accompanied by shaking with an intensity of VI-VII on the MSK-64 scale in the epicentral area and with an intensity of V in large cities of southern East Siberia (Irkutsk, Angarsk, Usolye-Sibirskoe, Zakamensk, etc.). A preliminary characteristic of the seismic event is given on the basis of a comprehensive analysis of seismological, structural-tectonic, strain, emanation, and hydrogeochemical data obtained during the monitoring of hazardous geologic processes in the Baikal natural territory. We have estimated the seismologic parameters of the Bystrinskoe earthquake, characterized the accompanying phenomena, and identified the effects that are of interest as probable precursors of future strong earthquakes in the Baikal region. The data obtained suggest that the earthquake occurred in the zone of the Main Sayan Fault as a result of strike-slip movement along the W-NW fault. The earthquake focus was apparently located at a shallow depth, as evidenced by the duration of the shocks, macroseismic manifestations, and the strong rumble heard at different directions from the epicenter.

High sensitivity spectra of the main ozone isotopologue were recorded using a cavity ring-down spectrometer in the region 7920-8670 cm^-1 covering the range up to the dissociation threshold and above. The sensitivity on the order 2 × 10^-11 cm^-1 was achieved. This makes it possible to detect high energy combination bands up to ten vibrational quanta in the electronic ground state. Line positions and intensities are measured for these bands. Vibronic hot bands of the ¹⁶O₃ borned by transitions from the (100) and (020) electronic ground state levels to the excited ³ A ₂ triplet state were recorded for the first time providing new information about the dependence of predissociation broadening on rotational quantum numbers.

Self- and air-broadening coefficients of nitrogen dioxide lines are calculated. The calculations are performed at a room temperature ( Т = 296 K) for ~ 29000 lines, rotational quantum numbers vary in the range up to 87 for N and up to 20 K_a . The temperature exponents are calculated for every line. The resulted parameters are compared with the literature and spectroscopic database. The calculations are made by two approaches: the semi-empirical method and energy difference method.

The peak positions and half-widths of the Q -branch of the n₁ band, as well as the ratios of intensities of the Q -branches of n₃ and 2n₂ bands of methane in a methane-helium mixture are measured at various pressures and concentrations. An empirical model has been developed for estimation of the helium concentration in a methane-bearing medium by measuring these spectral parameters. The error in the He concentration is found to be less than 1% when using the n₁ band half-width. The ways of developing this technique and increasing its accuracy are considered.

Experimental results are presented for self-broadening and shift of six isolated absorption lines of CO₂ versus pressure in the 1.6 mm spectral range at a room temperature. The measurements were carried out at a high-sensitivity high-resolution diode laser spectrometer with a signal-to-noise ratio of 3000 to 7000. To describe the experimental spectra, five theoretical line profile models VP, RP, qSDRP, qSDVP, and qSDVP + LM were used. A strong influence of weak closely spaced lines on the parameters retrieved (intensity and collisional broadening coefficient) of strong lines was found, as well as nonlinear pressure dependence of narrowing parameter for RP and qSDRP line profile models. The linear pressure dependence of the parameters retrieved for qSDVP + LM line profile is shown in the range from 0.001 to 1 atm.

Choice of the parameters of the lens raster in a Shack-Hartmann wavefront sensor with the minimal residual error in the wavefront reconstruction is one of the solutions to the problem of the sensor measurement accuracy. This paper presents the results of numerical experiments on estimating the accuracy of reconstruction of the wavefront distorted by atmospheric turbulence taking into account the transfer functions between the telescope and the sensor and between the raster and the photosensitive matrix of the receiving device.

Experimental results of comparison of two methods of multielement analysis of liquid-droplet aerosol based on spectral analysis of laser plasma radiation are presented. The features of the emission spectra of laser plasma arising as a result of laser breakdown (LIBS method) and of filamentation (R-FIBS method) in liquid droplet aerosol are investigated. A liquid-drop aerosol containing a Na solution is used. The experiments were carried out to determine the optimal use of the methods on mobile platforms. It is shown that, for both methods, there are optimal delay times of the start of signal registration relative to the start of plasma generation, at which the maximal signal-to-noise ratio is observed. The magnitude of these delays differs by three orders of magnitude when going from nanosecond to femtosecond pulses. For the LIBS method, the dependence of the signal-to-noise ratio was obtained for various focusing of laser radiation deep into the liquid-droplet cloud. The values of the Na limit of detection for both methods are determined.

We analyze the annual variations in the total ozone content (TOC) over Tomsk in period of 1994-2017 and integrated aerosol backscattering coefficient (IABC) in the period 2000-2016 obtained using M-124 ozonometer and lidar method, respectively. The correlation coefficient between these time series turned out to be -0.23, indicating that, although localized in the same altitude range, these time series are uncorrelated. Study of annual behaviors formed from these time series showed that TOC can be fitted by the function sin, while IABC, by the function cos. At the same time, both functions depend on a single parameter, i.e., the time in decades. This allowed us to conclude that the variations of these atmospheric constituents are formed mainly in two perpendicular directions. It is found that the annual behaviors of TOC and IABC consist of two sections, fitted by exponential curves.

This paper presents a study of the temperature of the mesopause region (~ 87 km) by measuring the emission of OH (3-1) at high latitude station Maimaga (63.04° N, 129.51° E) and comparing the results with the temperature data Aura (MLS) at 0.002 hPa during 2013-2018. The average rotational temperature of OH (3-1) was compared with Aura (MLS) measured temperatures ( T ) and the background temperatures ( T _bg) calculated from them. The obtained result indicates in favor of more correct comparison of the temperature OH (3-1) and temperature T _bg calculated from Aura (MLS) data. Comparison of the data mutually confirms the observation of elevated temperatures in the mesopause in the winter period 2014-2015. In the winter periods of 2013-2015, the seasonal course of the temperature OH (3-1) is ~ 10 K higher than the seasonal course of the temperature T _bg. During the winter periods of 2015-2018, although the temperature variations are close in value, the seasonal course of the temperature OH (3-1) continues to exceed the values of the seasonal course of temperature T _bg. In general, the temperature variations measured by two different methods are qualitatively consistent and reflect the nature of seasonal changes. Temperature differences can be explained by many factors, such as differences in measurement heights and methods.

The average annual temperature derivatives analysis was carried out according to the data of 927 weather stations of the Northern Hemisphere for the period 1956-2016. Changes in derivatives are considered as manifestations of the emergent property of a holistic climate system. A measure of these manifestations has been introduced. The measure has a functional form, including averaging positive and negative derivatives and calculating the correlation coefficients along weather stations. The extrema of the derivative temperatures are determined; it is found that the sample distribution of the sums of the opposite extrema of the derivatives is symmetric and has a greater kurtosis than the normal distribution. In the study period, the values of the measure are already close to their limiting values. At that, the climate system's equilibrium state is preserved, while regional fluctuations of individual climate elements have increased. Therefore, an annual assessment of changes in the multichannel monitoring system's measure of emergent properties is required.

Air-sea CO₂ exchange over the Gulf of Finland according to SOCOM ship measurements during March and April 2019 have been assessed to determine the possible impact of the water surface on estimates of St. Petersburg anthropogenic emissions. It was found that the surface of the Gulf of Finland is a source of CO₂ in March and a sink in April 2019. CO₂ fluxes per unit area of the water surface of the Gulf of Finland were on average significantly smaller (by 1-2 orders) than the anthropogenic emissions of St. Petersburg. Contribution of the Gulf of Finland surface to CO₂ content of air masses passing over the water surface in March-April 2019 was small on average in comparison with the contribution of St. Petersburg according to EMME (Emission Monitoring Mobile Experiment) measurements and ODIAC data (less than 1% of the cities contribution). For extreme wind speeds above the water surface and differences in the partial CO₂ pressure in water and air, the contribution of the Gulf of Finland to the CO₂ content of the air masses can reach almost 3% in relation to the anthropogenic contribution of St. Petersburg.

We show a possibility of measuring wind speed with a lidar and a sampling method developed. An experimental setup operating at an eye-safe 0.355 mm wavelength is described; corresponding measurement data are presented. The dependence of the measurement quality on optical properties of the atmosphere is analyzed. The mean absolute errors are 1.05 m/s for the wind speed and 13.3° for the wind direction calculated with accumulated measurements for spring-autumn is.

The paper describes the multi-conjugate adaptive optics systems and identifies the features of optical conjugations of adaptive mirrors with turbulent layers for ground-based solar telescopes. The optimal size of the field of view for a solar telescope operating under average atmospheric conditions has been calculated. The size of the optimal field of view is equal 10 arc. sec. Recommendations are given for the development of MCAO systems for ground-based solar telescopes. The concept of a system for determination of 3D wavefront distortions for the Large Solar Telescope LST-3, as well as for the wavefront registration in the Large Solar Vacuum Telescope, is proposed.

The ability of all living and developing things to adapt to environmental conditions, change them, find means and ways to protect and preserve themselves is called resilience and viability. There are many sciences that study the viability of living organisms and self-replicating systems as a whole and its individual aspects. This work aims to quantify the viability of the constituent entities (regions) in the Russian Federation. To achieve this goal, we use the author’s viability coefficient that shows the change in viability, not its absolute level; 15 indicators of the Federal State Statistics Service of the Russian Federation for 2000-2018 were used to calculate the viability coefficient in this study. Having analyzed the viability coefficients calculated for 79 Russian regions, we see that their dynamics fluctuated during those years. The falls coincided with periods of global financial/economic crises and unfavorable geopolitical events for Russia. The oscillations amplitude decreased, and the coefficient values were approaching one, which indicates decelerated or ceased viability growth. The results obtained could prove to be useful in studying the state of national security in Russia and its administrative-territorial entities, as well as drafting regional socio-economic and demographic policies.

A review of investigations dealing with mathematical and numerical modeling of shock wave and detonation processes in gas suspensions of fine-grained inert or reacting particles is presented. The basic models of mechanics of continuous media that describe rarefied gas suspensions and saturated powder media are mentioned and analyzed. Models with internal pressure in the particle phase, including those with the description of particle collision dynamics within the framework of molecular-kinetic approaches, are identified. Problems of interphase interaction and equations of state are discussed. Various issues of the qualitative analysis of the characteristic properties of models and theoretical analysis of shock wave structures (conditions on shock waves, classification of shock waves and combined discontinuities) are outlines. Most popular numerical algorithms used for simulations of shock wave processes are mentioned. Some results of numerical studies of the processes of detonation initiation and propagation, interaction of shock waves with clouds and layers of particles, and dispersion of the layers) are noted.

Four detailed chemical mechanisms used to describe detonation combustion of hydrogen in oxygen are considered. Ignition delays for various temperatures and pressures are found, The Chapman-Jouguet velocity is determined, and the Zel'dovich-Neumann-Doring solution for different models is obtained. The effect of dilution of the stoichiometric mixture of hydrogen and oxygen by an inert gas is estimated. Direct numerical simulation of detonation wave propagation in a channel is performed; the emergence of instability of the plane wave and formation of a cellular (multifront) structure are studied. The results predicted by different chemical models are analyzed and compared with each other and with available experimental data.

Fire accidents in closed regions, transport carriers, and auditoriums are influenced by the confinement conditions. The current experimental investigation is intended to find the effect of obstacles, obstacle-free space, gas flow, and near-wall turbulence on the flame acceleration. Two rows of bench-shaped obstacles (replicate chairs in transport carriers) enhance the flame speed in the obstacle-free path. Turbulence intensity is higher in local regions where the flow becomes highly subsonic and mildly supersonic, which enhances the flame speed. The flame front-driven supersonic flow can form negative shock waves, which can further increase the flame speed. Careful design of confined geometry can prevent accidents or slow down the flame propagation.

The study of the ballistic properties of energetic materials remains vital to ensure safety during their transportation, handling, storage, and processing. It might be a complex, expensive, and time-consuming process to evaluate the ballistic properties experimentally. This work proposes a simple numerical method to predict the ballistic properties of deflagrating energetic materials. Adiabatic and one-dimensional propagation of waves is assumed for theoretical evaluation, and the Rankine-Hugoniot equations are used to obtain correlations. The correlations are obtained in terms of the reactant mass to determine the ballistic properties, namely, the pressure, temperature, and velocity of the particle at the point of ignition. For determining the particle velocity and combustion wave velocity, theoretical correlations are also derived in terms of the mass and distance from the point of ignition. The theoretical calculation is compared and validated with experimental results. The deviation is found to be smaller than 2%. This simple calculation can be used for evaluating and comparing the ballistic properties of various deflagrating energetic materials without the need of performing complicated experiments.

This paper presents the results of an experimental study of the ignition and slagging characteristics during combustion of boron-containing solid propellants with ammonium perchlorate as an oxidizer under conditions simulating working processes in a gas generator and in the afterburner of a rocket-ramjet engine. It is shown that the introduction of fluorine-containing additives into the propellant reduces the content and adhesion of primary condensed combustion products (slags). The dependences of the ignition delay on the density of the radiant heat flux in the range 20 ÷ 180 W/cm² are obtained for model solid propellants containing boron, carbon, boron carbide, and slag particles collected in the gasifier.

Thermogravimetric analysis data were used to determine the activation energy E = 205.9 kJ/mol, the pre-exponential factor A = 2.275 x 10^-15 m³/s, and the order of the reaction with respect to the oxidizer m = 1 for the oxidation of an aluminum diboride particle leading to the formation of aluminum borate on the surface. The ignition conditions for a single particle of aluminum diboride in air were estimated using the theory of ignition of metal particles proceeding by the thermal explosion mechanism. It is shown that a consequence of the formation of aluminum borates in the induction period is a strong positive dependence of the ignition temperature of particles on their size and the partial pressure of oxygen.

A study of various macrokinetic modes of interaction (self-ignition or combustion) of compact samples from non-passivated (pyrophoric) and passivated iron nanopowders with air has been carried out. Experiments have shown that the modes of interaction with air depend on the type of gaseous medium used (argon or air), in which the bottles with the samples were previously located, as well as on the duration of the exposure of the bottles in air. For the first time, the possibility of passivation of pressed samples from pyrophoric iron nanopowder was experimentally established when weighing bottles with samples in air. Various experimental methods have been used to study the dynamics of heating the sample and the effect of density nonuniformity along the length of the sample on it. It was found that the heating of pyrophoric samples is nonuniform, although it begins simultaneously over the entire surface of the sample.

The influence of the content of polyvinyl butyral (0 ÷ 2.3 %) on the combustion of a granular mixture of Ti + C with titanium of different grades is investigated. The experiments were carried out in the absence of an external gas flow; therefore, due to the low decomposition temperature and a small amount of polyvinyl butyral, a conductive combustion mode was expected. However, for rapidly burning mixtures, a convective combustion mode was found due to the ignition of the granule surface with hot gaseous decomposition products of polyvinyl butyral. The mechanism of falling of undecomposed polyvinyl butyral behind the ignition front is explained. It was found that the combustion mode of the Ti + C granular mixture depends on the rate of its combustion in the absence of a gas flow through the sample. Based on the experimental and theoretical analysis of the combustion process, it has been established that the ignition of granules in the convective mode occurs at the temperature of the α®β-transition in titanium. A qualitative explanation is given for the different effect of the content of polyvinyl butyral on slow and fast burning mixtures Ti + C.

Structure of detonation waves in mixtures of tetranitromethane with methanol and nitrobenzene is studied using a multipoint laser interferometer. There is a poor reproducibility of the mass velocity profiles measured in different experiments with a fixed composition of mixtures. Simultaneous registration of wave profiles at several points of the detonation front and different sections of the sample showed that in this case the flow is one-dimensional and stable with respect to longitudinal perturbations. This means that in each experiment a stationary detonation mode is realized, the parameters of which differ from experiment to experiment. Along with the lack of reproducibility of the mass velocity profiles, nonclassical detonation modes were recorded in the mixtures under study, which are manifested in the absence of a chemical peak in the reaction zone. A possible relationship between these two phenomena is discussed.

The explosive tetrazene (1-amino-1(tetrazol-5-yl-diazenyl)guanidine monohydrate) has been actively used in initiating compositions since the beginning of the 20th century, but it has low thermal and hydrolytic stability. As an alternative to tetrazene it was proposed to use 2-(tetrazol-5-yl-diazenyl)guanidine (MTX-1), which is its more thermally stable derivative. However, the decision on the applicability of a particular explosive is primarily made based on its explosive properties, which are not well known for both tetrazene and MTX-1. The objectives of this study was to determine the detonation velocity and heat of explosion of MTX-1 in comparison with tetrazene and explain the results obtained. Calorimetric measurements were carried out in a modified steel bomb. Samples of MTX-1 and tetrazene »1 g) were exploded in helium to determine the heat of explosion and the volume of gases. Experimental data on the critical diameter of both substances were obtained. The detonation velocities of MTX-1 and tetrazene were determined by an electromagnetic method.

Detonation of PETN and HMX with a particle size of about 1  m was investigated by an electromagnetic method. At an initial density of 0.9 ÷ 1.2 g/cm³, the von Neumann spike was weak or not observed at all. This indicates a fast reaction, whose time is outside the experimental resolution (about 5 ns). Electrical conductivity measurements provided only a rather rough upper-bound estimate of the reaction time (less than tens of nanoseconds). Density measurements using synchrotron radiation showed that the initiation of PETN with an air shock wave led to almost instantaneous detonation initiation, without any acceleration region. In general, the results of the study confirm the acceleration of the chemical reaction in ultrafine explosives.

This paper presents the results of a study of the initiation of explosive transformation of flat charges 40 mm in diameter and 5 mm thick, made of a low-density (&rho:ρ» 0.9 g/cm³) light-sensitive explosive composition based on fine RDX and aluminum. It is shown that laser radiation (LR) can be used to initiate explosive transformation on a large area (»1 000 mm²) with a small difference in the time of arrival of the detonation wave front. It is determined that at a LR energy density Q_opt = 10 J/cm²) over the entire LR spot on the charge surface, the difference in the time of arrival of the detonation wave front at the rear surface of the charge is not more than 50 ns.

The ignition behavior of the polytetrafluoroethylene/aluminum/tungsten reactive projectile impacting a fuel-filled tank is experimentally investigated. In ballistic experiments, the reactive projectiles and the steel projectiles are launched from a smooth bore powder gun barrel to impact fuel-filled tanks at different velocities. The processes are recorded by a high-speed video camera. The result of the ignition-enhanced behavior of the reactive projectile relative to the steel projectile is presented. When the reactive projectile impacts the fuel-filled tank, the combined effects of the kinetic energy impact and the chemical energy release are achieved to improve the ignition probability. Especially, the flame (ignition kernel of the fuel) caused by the reactive projectile has a longer duration and a greater expansion region

The question of whether the physical state of shock-compressed copper is in equilibrium is discussed. For this, experimental data on defect electrical resistivity are used to estimate the concentration of point defects. Quantitative information on the concentration of defects can be obtained if the type of arising defects is known. Assuming the predominant formation of vacancies, the dependence of the concentration of defects in copper on the pressure of the shock wave is obtained. It is shown that the number of defects monotonically increases with increasing pressure of the shock wave. The found concentration of vacancies »0.8 % at a pressure of 20 GPa) exceeds the corresponding equilibrium value by ten orders of magnitude. Thus, the state of copper under shock compression is highly defective and highly nonequilibrium. Comparison of data for shock-compressed copper and silver shows the general features of the state of these metals. Comparison of the data obtained immediately after the passage of the shock wave through the sample (in situ) with the known results for the samples preserved after the experiment demonstrates that in the first case, noticeably higher (up to two orders of magnitude) defect concentrations are recorded. Thus, the technique of stored samples does not provide objective information on the state of matter directly behind the shock front. The problem of constructing the equation of state under conditions of nonequilibrium physical state is briefly discussed.

The thermodynamic analysis and tests of minerogenesis under higher temperatures determine conditions of thermochemical decomposition of hydrophilic attachments on diamond surface. It is found that hydrophilic mineral attachments can be removed from diamond surface by combining thermal treatment of slurry at the temperature of 80-85 °С with electrochemical treatment of recirculated water, which enables required change in ion-molecule composition of water phase in the slurry. The hybrid conditioning technology ensures recovery of the natural hydrophobic behavior and floatability of diamonds and enhances performance of froth flotation of diamonds by 5.1%.

The adsorption properties of electrochemically and thermally modified saponite relative to heavy metals are analyzed. The tests have found the efficient use and regeneration parameters of the sorbent to ensure maximized adsorption of cations of heavy metals and to enable production of pregnant solutions with high concentrations of heavy metals.

Dissociation of gold particles is tested in disintegration of Gurbey deposit ore samples under multiple impact effects in crusher DKD-300. It is found that in disintegration of gold-bearing schistose quartz ore, dissociation of gold particles larger than 100 μm in size extractable by gravity reaches 47%. The test results are confirmed by the data of the automated mineralogical analysis on scanning electron microscope TESCAN TIMA.

Occurrence and mineralogy of economically important rare-metal mineralization from pegmatite of Wadi El Sheih granite, Central Eastern Desert of Egypt, was previously discussed. The mineralogical investigation of the bulk composite sample collected from the studied pegmatite revealed the presence of 7.59% by mass heavy economic polymetallic minerals such as euxenite-(Y), fergusonite-(Y), allanite-(Ce), xenotime-(Y), uranothorite and zircon. This work investigated the use of high intensity magnetic separator in conjunction with gravity pre-concentration steps via shaking table concentrator to recover rare-metals and rare earth bearing mineralization of Wadi El Sheih pegmatitic granitoid sample. The results of magnetic separation are related to the magnetic susceptibility measurements of pure single crystal minerals using vibrating sample magnetometer instruments.

The flowchart is developed for gold ore flotation at the reduced impurity of the rougher flotation product with difficult middlings. The rougher flotation concentrate is subjected to scavenging by aerated air and hot steam mixture. In cold pulp slurry, the steam condensation heat is removed from bubbles to wetting films. With increasing temperature, the hydrophilic repulsive forces, that stabilize the films, can be reduced to excess osmotic pressure between the hydrophilic surfaces, and the instability of the films between the hydrophobic surfaces can be reduced to excess osmotic pressure of surrounding water, i.e. to the hydrophobic attraction forces. The test machine is designed to measure heat-transfer coefficients during aeration of water by air-steam mixture. The revealed heat loss patterns enable determining the efficient steam flow to ensure water heating in the interfacial layers of bubbles at the minimized loss of the heat source. Using an ore sample, it is demonstrated that it is possible to enhance gold recovery using the designed circuit of rougher flotation and the method of rougher concentrate scavenging.

The authors propose a mathematical model of salt particulate dynamics in a roadway, including convection and diffusion of particles with air flow, coagulation of particles, condensation of water on them, and gravity deposition of particles on the roadway floor. Using the finite difference method, the problem on flow of salt particulates in a roadway is solved, and the particulate concentrations and the average size of particles are determined. The calculations are compared with the analytical model and full-scale test data. The found correlation between the particulate deposition velocity and the aerosol parameters can be used for the parametrization of mathematical models of air-dust mixture flow in ventilation networks of potash mines.

The ground control using optical fibers is discussed. The designed monomode fiber pressure sensor is capable to perform high-precision measurement of overlying rock mass pressure imposed on walls of underground excavation. The mathematical apparatus is presented for the calculation of radiation intensity of optical wave travelling along an optical fiber with and with no mechanical effects. The simulation model is developed for an underground excavation with steal arch support. The model is equipped with the fiber-optic monitoring system and pressure sensors. This model enables practicing the ground control methods and measurements. The critical element of the simulation model is its hardware/software complex with interface showing four check zones with fiber-optic pressure sensors. This monitoring system is explosion-proof and is suitable for operation in super hazardous mines in terms of gas and dust outbursts.