Home – Home – Jornals – Journal of Mining Sciences 2022 number 2

We have studied an Upper Devonian volcanoterrigenous carbonate complex in the north of the Kuznetsk trough. The northern part of the complex is subducted beneath the Meso-Cenozoic sedimentary cover of the West Siberian geosyneclise. Analysis of sedimentologic processes, the nature and specific composition of pyroclastic impurity, and the petrographic and chemical compositions of sedimentary rocks makes it possible to reconstruct the facies and geodynamic settings. It is shown that the fine-grained pyroclastic material is predominantly of andesite composition, whereas felsic and mafic volcanic components are subordinate. In the transition from the lower Frasnian to the Famennian, the content of felsic pyroclastic component increases. The geodynamic settings of the shelf and continental slope of the Siberian continent up to its base have been established. Facies analysis shows that the slope is west-facing (in the present-day coordinates). The deposits accumulated mainly in the basin; these are fine-grained terrigenous rocks, fine-grained limestones, slope landslide breccias and olistostromes, turbidites, and “conglomerate-like limestones” (paleoseismites). According to the geochemical data, the Late Devonian paleogeodynamic setting was stable and corresponded to the setting of an active continental margin. Arid to semihumid lithogenesis has been established. Marine sediments formed in an oxidizing environment with good water aeration.

Concepts of the stratigraphy of the coastal and shallow-sea sections of the uppermost Middle Jurassic and Lower Cretaceous, exposed on the right bank of the Anabar River, have radically changed many times. The performed study and analysis of the published data are aimed at refining the bio- and lithostratigraphic subdivision of the section, substantiating its stratigraphic completeness, and describing the identified stratigraphic units in detail. Comprehensive biostratigraphic studies of the uppermost Bathonian-lowermost Boreal Berriasian reveal a sequence of nine biostratigraphic units with dinocysts and palynoflora in the ranks of zones and local zones. Some of the palynological biostratigraphic units have been identified for the first time. Foraminifer assemblages of the boreal standard zones are recorded in the sections under study. The obtained biostratigraphic data and analysis of all known ammonite occurrences make it possible to demonstrate the stratigraphic continuity of the section in the Anabar River region, despite the reduced thickness of the stratigraphic units. The stratigraphic position of the boundary between the Sodiemykha and Buolkalakh formations is accurately defined. According to the interpretation proposed, the basal horizon of the Buolkalakh Formation is associated with a beginning of a new major sedimentation stage in the late Oxfordian-early Kimmeridgian, identified as the lower boundary of lithostratigraphic units of different ranks throughout the entire Arctic Region and partially in the Boreal Region. The lithogeochemical parameters of the studied formations are obtained for the first time. The content of C_org in the studied samples does not exceed its Clarke values, and the pyrolytic parameter T _max indicates that the organic matter is immature and the petroleum potential is low. The considered organic matter of the rocks is characterized by a heavy isotope composition of carbon, suggesting its mostly terrigenous genesis.

Structural and lithological comparison of intraformational plicative liquefaction deformations (convolutions) in Late Quaternary lacustrine complexes of the Baltic Shield (sediments of small glacial lakes) and the Tien Shan (sediments of a large stationary basin in the Issyk-Kul depression) is carried out in order to clarify their genesis. These regions have sharply different levels of seismotectonic activity, which makes it possible to most fully determine the role of a seismic factor in the formation of bedding disturbances. Convolutions in the Baltic Shield are represented by load casts, flame structures, pseudonodules, and regular folds with more pronounced anticlinal bends. It is shown that convolutions occur here only in the most liquefied soils (siltstones and fine-grained sands) with low cohesion and fluid permeability in the case of unstable (increased density and coarsening of the sediment from bottom to top) or neutral (homogeneous composition) stratification of weakly consolidated sediments, and the ratio of the widths of the synclinal and anticlinal parts of the folds ( K _syn) for these structures is 1.0-7.5. These signs point to the formation of disturbances because of a spontaneous instability or an instability initiated by weak mechanical influences in the sedimentary stratum under conditions of a normal vertical gradient of the sediment viscosity. Deformations in the second region are structures typical of the Baltic Shield, columnar structures of deep interpenetration of layers, diapirs, and clastic dikes. There are also flexural folds with K _syn ≈ 1, which formed at a higher degree of sediment consolidation than the actual liquefaction structures. The convolutions of the Issyk-Kul depression are developed not only in sand-silty sediments but also in relatively lowly liquefied soils (clay, gravel, and pebbles). These structures formed under both unstable and stable density stratification of the sediment (for example, clay-on-sand), and K _syn = 0.3-2.5. Thus, the formation of convolute structures in the Issyk-Kul depression is impossible without strong dynamic impacts on stratified sediments during their accumulation. The results obtained make it possible to substantiate the predominantly diagenetic (convective and landslide) genesis of convolutions in the lacustrine complexes of the Baltic Shield and the seismogenic genesis in the limnogenic deposits of the Tien Shan. A number of new criteria for identifying seismites are proposed, which determines the practical significance of the study.

Bottom sediments of lakes are regarded as one of the most informative continental facies used to reconstruct environmental changes in lake catchments. They usually contain a high-resolution and continuous record of geologic events, the knowledge of which is important for understanding the evolution of sedimentary processes and landscapes under the influence of climatic changes and the impact of short-lived catastrophic processes. The southwestern Baikal region (the Tunka rift and its East Sayan mountain framing) is replete with lakes of different geneses and morphologies. Recent fieldworks have allowed a multiproxy study of the lacustrine sediments of several lakes of the Oka and Tunka regions. The results demonstrate that there were no glaciers in the foothill plain of the Tunka rift valley earlier than 14,800 cal yr BP. On the Oka plateau, within the East Sayan high-mountain zone, deglaciation started somewhat earlier than 13,800 cal yr BP. The grain size, petromagnetic, and physical properties of the lacustrine sediments point to a general weak hydrodynamics throughout the 13,800 yr sedimentation history in Lake Khikushka. However, a gradual reduction in fine fractions from base to top of the lake section suggests a gradual drawdown of the water level following the change of the water source from glacial melt waters to atmospheric precipitation. Biogenic silt accumulation in Lake Khikushka started parallel with the onset of the Holocene ~11,700 yr BP, suggesting a quick response of the natural environment of the lake basin to major global climatic changes. The short-term episodes of enhanced hydrodynamics in Lake Khikushka ~9000, 8200, 6500, and 2000 yr BP confirm the high sensitivity of the lake geosystem to climatic changes, not only on a millennial but also on a shorter-time scale. The characteristics of the sediments of Lake Engarginskoe are evident of lacustrine-alluvial sedimentation in the reservoir in the Early and Middle Holocene. New data on the grain size and petromagnetic parameters of the lacustrine sediments from two lakes located within different climatic belts of East Sayan show their high potential for a wide range of paleoecological reconstructions.

The paper presents the U-Pb age of zircons and the geochemical and isotope characteristics of granitoids from the Kitoi block (Sharyzhalgai uplift, southwestern Siberian craton). The studied granitoids compose different-scale vein bodies. According to the structural relations among the rocks and their U-Pb zircon ages, there were three stages of early Precambrian granite formation: ~2.99, 2.54, and 1.88 Ga. The Neoarchean and Paleoproterozoic granites contain inherited zircons dated at ~2.97-3.00 Ga, which are close in age to magmatic zircons from the Mezoarchean granite-gneiss. The Kitoi granitoids of different ages show similar enrichment in SiO₂, K₂O, and incompatible trace elements. In trace element composition and crystallization temperatures the Mesoarchean granite-gneisses are similar to A-type granites, while the Neoarchean and Paleoproterozoic granitoids, to I-type ones. The inherited ~2.97-3.00 Ga zircons and narrow range of model Nd ages ( T _Nd(DM) = 3.0-3.3 Ga) indicate that the Neoarchean and Paleoproterozoic granitoids formed through the recycling of the Mesoarchean crust. The Neoarchean (~2.54 Ga) and Paleoproterozoic (~1.88 Ga) stages of granite emplacement in the northwest of the Kitoi block correlate with the formation of granitoids and high-temperature metamorphism in the Irkut block and the border zone between the two blocks. The subsynchronous granite formation and metamorphism (~2.54 Ga) give strong evidence that the amalgamation of the Kitoi and Irkut blocks resulted from collisional orogeny in the terminal Neoarchean.

Coal fires are a phenomenon that can be observed worldwide in areas where rocks containing coal seams are exposed and can pose major environmental threats. A coal fire can begin through spontaneous combustion when coals are exposed to dry and oxygen-rich near-surface conditions. Burning, depending on the temperature of heating, causes baking or even melting of the surrounding rocks and the formation of different types of combustion metamorphic rocks. In Northwestern China, coal fire occurrences are concentrated at the edges of the sedimentary basins or at the margins of orogenic belts, where coalrich units were exposed owing to the Indo-Eurasian collision. On the northern margin of the Tianshan range, evidence of coal fires is widespread in the Jurassic sedimentary units containing coal seams which outcrop along the Central Asian Orogenic Belt. In some cases, coal fires are active and can be linked to ongoing mining activity, but outcrops of combustion metamorphic rocks not associated with fires are also found and are indicative of past burning events. We examine combustion metamorphic rocks outcropping in the Toutunhe River valley (Liuhuangou area, Xinjiang, Northwestern China). Combustion metamorphic rocks in the study area were mapped and classified according to their morphological and mineralogical characteristics. Outcrops are exposed at various heights on the valley flanks, which are characterized by the presence of multiple levels of fluvial terraces. These terraces are indicative of the phases of erosion and deposition of the Toutunhe River and testify to tectonic uplift. The investigation of the stratigraphic and crosscutting relationship of combustion metamorphic rocks with terrace deposits and apatite fissiontrack dating made it possible to determine that at least four phases of coal fire activity occurred from late Miocene to Quaternary. The first and oldest burning phase dates back to 10 ± 1.3 Ma and terminated prior to 2-3 Ma; the second was active before ~550 ka; the third had terminated by ~140 ka; the fourth began later than ~5.7 ka. The relationships between combustion metamorphic rocks and fluvial terraces further suggest that coal fire ignition/extinction in the area since the Miocene have been linked to the interplay between the uplift of the Central Asian Orogenic Belt and the phases of fluvial erosion and deposition in interglacial periods.

Methods for determining the domain structure of thin ferroelectric films from the time dependence of the pyroelectric response to short pulsed surface heating are considered. The problem of finding the distribution of the pyroelectric constant over the thickness from the time dependence of the pyroelectric current is the solution of the Fredholm equation of the first kind. Despite the fact that this problem is ill-posed in general, it can be solved under additional assumptions about the resolvent. The assumption that the domains are wedges allows the depth distribution of the pyroelectric constant in a thin barium-strontium niobate film to be determined.

Various methods of adaptive space-time signal processing in a survey radar system with a digital antenna array and wideband sounding signals intensively influenced by active and passive interferences are considered. Approaches to simulation of interferences acting on radars and their suppression by adaptive signal processing are discussed. It is proposed to simulate signals and interferences and their processing after transformation to the complex envelope in the frequency domain.

The problem of segmentation of natural and anthropogenic objects from panchromatic satellite images of very high spatial resolution (< 1 m) using texture analysis is considered. The effectiveness of various statistical methods for extracting texture features is analyzed. Based on the results of numerical experiments represented in this paper, we have selected methods that make it possible to segment the main types of natural and anthropogenic objects, as well as various structures of the forest canopy, with high accuracy (> 95%). We proposed the TTSPCA method, which allows the joined use of the most informative features extracted by different statistical methods. The results of numerical experiments show that the method proposed has higher texture segmentation accuracy (> 99%) in comparison with the standard texture extraction methods considered in this paper.

We discuss the technology of data processing for the AIRS hyperspectral suite and AMSU-A microwave sounder installed on board the Aqua satellite. This technology makes it possible to retrieve geophysical parameters of the Earth’s atmosphere and surface even with 80 % coverage of an observation area by clouds. The failure of the AMSU-A sounder in 2016 led to exclusion of its readings from the AIRS data processing scheme and to implementation of the simplified AIRS Only algorithm used today by NASA. In this paper we propose an approach to repair the AIRS «all-weather mode» using data from the ATMS scanning microwave radiometer on board the Suomi-NPP and NOAA-20 satellites. It is shown that the inclusion of the ATMS readings in the data processing algorithm makes it possible to obtain geophysical results that practically coincide with the original AIRS/AMSU data.

A method for estimating the nonlinear functional of the probability density of a three-dimensional random variable is proposed. It is relevant in the implementation of procedures for fast bandwidths selection in the problem of optimizing kernel estimates of the probability density. Solving this problem can significantly improve the computational efficiency of nonparametric decision rules. The proposed approach is based on the analysis of the formula for the optimal bandwidths of the kernel probability density estimate. The bandwidths of the kernel functions are represented as the product of an undefined parameter and the standard deviations of the analyzed random variables. The main component of the undefined parameter is a nonlinear functional of the probability density. The considered functional for a family of unimodal distribution laws is determined by the form of the probability density and does not depend on the density parameters. It is determined by the approximation of the functional dependence on the antikurtosis and skewness coefficients, which are estimated from the initial statistical data. To simplify the problem of restoring the desired dependence, the antikurtosis and skewness coefficients are transformed into a generalized parameter. The initial information is made up of a family of lognormal distribution laws. The errors of approximation of the considered nonlinear functional of the probability density are estimated by the values of the introduced generalized parameter for a family of three-dimensional lognormal distribution laws of independent random variables. The possibility of using the proposed methodology for estimating nonlinear functionals of the probability densities that differ from lognormal distribution laws is investigated. The influence of the arising approximation errors on the mean square criteria for recovering a nonparametric probability density estimate of a three-dimensional random variable is analyzed.

The features of carrying out X-ray lithography by synchrotron radiation (SI) using masks on thin (up to 50 microns) and thick (up to 1 mm) layers of X-ray resists are described with an illustration on specific examples of X-ray lithography stations of the VEPP-3 storage ring. The calculated graphs of the spectral dependence of the resolution of X-ray lithography on the size of the gap between the working surfaces of the X-ray mask and the substrate being processed, graphs of the dependences of the SI beam intensity and the absorbed power density on the depth of radiation penetration into the resist, and similar graphs for the contrast of the X-ray mask are presented. A description of self-supporting perforated (with through holes) metal X-ray masks is given. Reaching a new qualitative level of their production by laser cutting with a femtosecond pulse duration is illustrated by SEM photos, which will allow obtaining samples of planar elements of terahertz optics in the form of metal microstructures formed by means of the LIGA technology, varying the cell sizes, the width of “the line” of structures, and their thickness in a significantly wider range than was done earlier.

The optimal design of a cooled flip-chip photodetector in the infrared spectral range for installation in a cryostat is determined both with the possibility of bending during cooling and with rigid attachment to a pedestal through a sapphire plate. A numerical calculation is carried out for a radially symmetric photodetector model: GaAs (first layer) - Indium (ring structures) - Si - GaAs (second layer) with a plate diameter of 10 mm. The maximum deformation loads in the edge indium ring are determined for plates of different thicknesses (from 0 to 700 μm), which occur when the photodetector is cooled to 77 K. For the photodetector model, when it is fixed on a cooled cryostat pedestal with the possibility of bending, the optimal design is determined - GaAs(1) and Si plates with a thickness of about 50 μm and without GaAs(2;, the maximum deformation loads in the edge indium ring (width 15 μm, thickness 5 µm) with this configuration are approximately 427 MPa. When the model is rigidly mounted on the pedestal of the cryostat, the optimal design is GaAs(1) and Si plates 50 µm thick and a GaAs(2) compensation layer 100 µm thick; the maximum deformation loads in the edge indium ring under these conditions are 600 MPa.

Propagation of high-power phase-modulated femtosecond laser pulses in air is numerically simulated. Spatial modulation of the initial pulse wavefront is carried out using a programmable phase plate consisting of segments arranged in a checkerboard pattern with a variable wave phase jump. The self-focusing, filamentation and post-filamentation channeling of radiation for phase-modulating masks with different phase shifts at the boundaries of neighboring segments are studied within the numerical solution of the nonlinear Schrödinger equation for the time-averaged electric field amplitude. The filamentation domain in air for certain pulse phase modulation types is shown to be significantly shifted (along the coordinate) and elongated compared to an unmodulated pulse. In addition, it is found that the use of phase modulation makes it possible to reduce the angular divergence of high-intensity light channels generated during the post-filamentation propagation stage. This provides a possibility of self-channeling of radiation at distances multiple of the Rayleigh length.

The results of analysis of aerosol of an aqueous solution of NaCl by femtosecond-pulse laser-induced breakdown spectroscopy (FS-LIBS) are considered. The results of estimating the impurity (Na) concentration by the analytical pair method using the additive method are presented. The radiation of the atomic nitrogen ion N⁺ at a wavelength of 500.515 nm from atmospheric nitrogen molecules in the filamentation region was taken as the internal standard line. A possibility of estimating the concentration of the both desired substances, the radiation of which is recorded, and the compound containing it is shown. The results are of interest for the development of femtosecond lidar sensing methods.

We present the results of calculating the vibrational and rotational terms of the X²Π and B²Σ⁺ electronic states of the phosphorus oxide (PO) molecule. The absorption spectrum corresponding to the electronic transition B²Σ⁺ (v′ = 0) - X²Π (v″ = 0) has been calculated. The efficiency of laser excitation of PO molecules is estimated as a function of the spectral parameters of the radiation. It has been established that the excitation efficiency of the B²Σ⁺ (v′ = 0) - X²Π (v″ = 0) electronic transition of the PO molecule is approximately an order of magnitude lower than that of the A²Σ⁺ (v′ = 0) - X²Π (v″ = 0) transition. The result is of practical importance from the point of view of choosing the optimal scheme for laser excitation of the fluorescence of PO-fragments in the implementation of the method of remote detection of organophosphates.

The results of the laser granulometry of nanosize fraction of precipitated aerosols and UV spectrometry of water washes from the surfaces of needle of different age of four species of forest-forming plant species are analyzed. The phenolic compounds efflorescence activity on the needle surfaces is assessed for the period of winter dormancy of plants. A possibility of the secondary organic aerosols geeration as a result of photoactivated reactions between phenolic compounds and a precipitated aerosol substance has been shown. The possibility of secondary organic aerosols entering the winter forest canopy under the radiometric photophoresis is discussed. It is assumed that secondary aerosols photophoresis in the field of IR from the snow cover surface (“snow” photophoresis) can significantly affect the vertical transfer of secondary organic aerosols in the winter coniferous forest canopy.

The dependence of the intensity of emission lines Ca (393.3, 396.8, 422.6 nm), Mg (383.6 nm), and Na (589 nm) on the laser pulse duration in the method of filament-induced breakdown spectroscopy is investigated. The filament was excited in seawater aerosols droplets of 0.8-2 mm in size by laser pulses of 70, 230, 500, and 900 fs in duration at a constant pulse energy of 3.0 mJ. It is shown that with an increase in the laser pulse duration, the intensity of the emission lines of the studied elements increased, with the exception of the magnesium line. Optimal values of the laser pulse duration for the excitation of Ca, Mg, and Na lines in a seawater aerosol are derived.

The turbulence parameters obtained using lidar are compared with the parameters determined from the average values of velocity and temperature in the surface air layer. The results of observations of the structural constant of the refractive index C_n² obtained from the ratio of the turbulent lidar returns in the surface air layer when working along a slightly inclined sounding path are presented. A method for determining the rate of kinetic energy dissipation from lidar data has been tested.

In winters-springs 2010/2011 and 2019/2020, there were the strongest anomalies of ozone layer in the Arctic stratosphere in the total satellite era. They were due to extraordinarily strong and long-lived stratospheric polar vortices, entailing unprecedented chemical ozone destruction. The analysis of the TEMIS data indicates that the total ozone content (TOC) deviations from the multiyear (2003-2019 except 2011) average were from 37 to 44% in 2011 and from 45 to 55% in 2020 at Arctic observation stations; and from 27 to 36% in 2011 and from 27 to 32% in 2020 in the subarctic latitudes. Based on the Aura MLS data, the minimal temperatures were 8-12% below normal over the Arctic in 2011 and 8-13% below normal in 2020. The ozone concentration dropped to 23% of the multiyear average at an altitude of 20 km on March 22, 2011, and to 6% at an altitude of 19 km on April 15, 2020, for Alert. A detailed correlation analysis showed that the deviations in the concentrations of water vapor and ozone, water vapor and temperature, and ozone and temperature correlate stronger in 2020 than in 2011. The correlations decrease toward the vortex periphery owing to the exchange of air masses between the Arctic and middle latitudes, becoming weakly significant outside the Arctic circle.

Generation of fogs downstream of the Krasnoyarsk hydropower plant on the Yenisei River during 2020 is studied. Meteorological conditions at the time of fog generation were recorded on the geoportal developed by the authors; water temperatures were taken at a gauging station; fogs were recorded with the help of video surveillance cameras. Data analysis showed generation of advective cooling fogs in summer and advective steam fogs in winter, early spring, and autumn. Cooling fogs are generated due to the cooling of the moist air as the lower atmosphere interacts with a colder moving water surface. Steam fogs result from the advective cooling of water vapor on the river surface by the colder adjacent atmosphere. The spatial distribution of steam fogs was derived from remote sensing data.

The results of mathematical simulation of biogeochemical processes during the autumn cooling of the lake are presented. The influence of wind on the distribution of phyto- and zooplankton, nitrate, ammonium, and phosphate nutrients is studied during the existence of the autumnal thermal bar in Barguzin Bay of Lake Baikal. Numerical simulations show the autumnal thermal bar in combination with the effect of western winds, which act opposite to the thermal front direction, to significantly slow down the transport of plankton biomass toward the central part of the bay.

He methods and results of numerical prediction of the maximum thickness of ice deposits are described. The success of ice deposition forecasts is estimated from calculations based on the WRF-ARW model output for different Russian regions.

An algorithm is developed and, on its basis, a software product is created to control the photon counter and to save the data from recording system of the lidar’s receiving channel at wavelengths of 299/341 nm in atmospheric sensing with a spatial resolution from 1.5 to 150 m. The main software options are: device connection check; receiving lidar sensing data; data digitization; graphical displaying; data filing; conversion of .dat into .txt file format. The software product is experimentally tested along with the mobile ozone lidar receiver unit, incorporated into the software part of the measurement complex of the Siberian Lidar Station. The receiver unit of the mobile ozone lidar comprises a photon counter PHCOUNT_4Е and Hamamatsu photoelectronic multipliers H12386-210. We present the atmospheric lidar sensing data and an ozone concentration profile retrieved in 2022.

The effect of collisional line broadening on the accuracy of tropospheric (0-11 km) temperature measurements with pure rotational Raman (PPR) lidars at their absolute calibration by spectroscopic parameters was estimated via numerical simulation. The simulation was performed for five sets of spectral filters (SF) with different passbands in a lidar spectral selection unit and an outgoing laser signal wavelength of 355 nm. It is shown that the unavoidable absolute calibration error can reach values from 0.14 to 0.44 K (depending on the SF set) when ignoring the N₂ and O₂ PRR line broadening. The line broadening can be neglected if only one PRR line is extracted in each of the two lidar channels (for example, using a Fabry-Perot interferometer).

A viscous liquid flow along a semi-infinite plate with small periodic irregularities on the surface was considered for large Reynolds numbers. The flow near the plate is described by Prandtl equations with induced pressure which are non-classical PDE, because they contain a limiting term. The main goal is to construct a numerical algorithm for solving these equations with periodic boundary conditions. The results of numerical modeling of the flow are presented.

This paper is devoted to the substantiation of a multiplicative model of time series decomposition based on the axiomatic approach. In this model, the original time series is represented as a component-by-component product of the selected components. The components are described in the form of monomials. To determine the values of variable monomials, a function is minimized that measures deviations from the unit of all components of the product of the selected components from the values of the corresponding components of the original series. In the model under consideration, all the components of the original series and the selected components are positive numbers. Four requirements are formulated for methods of selecting components. It is proved that all these requirements are met if and only if the time series decomposition is performed by a multiplicative model. As an example, we consider a model for selecting trends and seasonal fluctuations from monthly series of efficient data.

Based on the previously developed kinetic model of the catalytic reaction of the synthesis of benzylalkyl ethers, two- and three-criteria optimization of the conditions was carried out. The problem of multicriteria optimization is formulated with the definition of variable parameters: reaction temperature, proportionality coefficient of the starting reagents, reaction time; optimality criteria: yield of a target and by-products; restrictions on variable parameters. The computational aspects of multicriteria optimization by a grid algorithm (sensing) are examined. The calculated front values (optimality criteria) and Pareto sets (variable parameters) determine the exhaustive values of the reaction conditions and allow the decision maker to choose the most optimal ones. This made it possible to give technological recommendations for the industrial implementation of the synthesis of a benzyl butyl ether in the presence of a metal complex catalyst with a maximum yield of target products and a minimum content of by-products.

In this paper, one construction of the original «Harten-Lax-van Leer» method using a piecewise-linear reconstruction of physical variables is described. The obtained numerical method makes possible to reproduce a low-dissipation solution at discontinuities. To verify the method, we used the classical problems with an analytical solution based on various configurations of shock waves, contact discontinuities, and rarefaction waves. On the Sod-like problem, the order of accuracy of the developed numerical method was studied, it was shown that the main suppression of the order of accuracy occurs when the rarefaction wave is reproduced. The numerical method was verified by means of a three-dimensional Sedov test of a point explosion, and on the problem of a supernova Ia type explosion with two symmetric ignition points, leading to the formation of a G1.9+0.3 like remnant.

This paper considers the problem of phases probability distribution function estimation for phase-shift-keying signals. The modulating sequence, and, accordingly, the values of the symbols phases, as well as the statistical characteristics of this sequence are unknown. The Fourier coefficients are calculated based on a limited sample for estimation of phases probability distribution function. In this case, the obtained Fourier coefficients are regularized. Application of multiparameter regularization for increasing the estimation accuracy are considered. The numerical simulation results are presented.

Resistance to HIV-1 disease developed by some exposed individuals has shown a promising sign in the fight against HIV-1 infection. Behavior change has also become one of the most important protection strategies against HIV-1 pandemic, but both of them have been widely neglected by mathematical modelers. In this paper, a new virus resistance HIV-1 mathematical model incorporating behavior change is formulated and analyzed rigorously for both partial and total abstinence cases. The calculated reproduction number is used to establish the local stability of the disease-free equilibrium points using the approach of Watmough and Driessche in both cases. Using appropriate demographic and epidemiological data for South Africa in the numerical simulation, the positive effect of behavior change in the midst of HIV-1 resistance is thoroughly examined, and this strategy is absolutely effective in dealing with the threat of HIV-1. This work also provides a better result than what is obtainable in the majority of the referenced related works.

In this work, we deal with a convex quadratic problem with inequality constraints. We use a logarithmic barrier method based on some new approximate functions. These functions have the advantage that they allow computing the displacement step easily and without consuming much time contrary to a line search method, which is time-consuming and expensive to identify the displacement step. We have developed an implementation with MATLAB and conducted numerical tests on some examples of considerable size. The obtained numerical results show the accuracy and efficiency of our approach.

The present article deals with approximation results by means of the Lipschitz maximal function, Ditzian-Totik modulus of smoothness, and Lipschitz type space having two parameters for the summation-integral type operators defined by Mishra and Yadav [22]. Further, we determine the rate of convergence in terms of the derivative of bounded variation. To estimate the quantitative results of the defined operators, we establish quantitative Voronovskaya type and Gruss type theorems. Moreover; examples are given with graphical representation to support the main results.

The article describes the lab-scale testing of dynamic instability in a block placed on a rough slope surface and subjected to small-amplitude vibrations. It is shown that the macroscopic sliding evolution is well-presented using equations of creep with the properly selected constants. According to the testing data, the necessary condition of the dynamic failure is the critical displacement along the slope and the certain creep rate. The critical displacement appears to exceed greatly the typical value when the sliding surface transits to the residual shear resistance. It is found that the landslide body instability develops at the late stage due to the phenomenon of reduction in friction at increasing sliding velocity.

The granular and other similar-type materials without cohesion are tested on various mode shearing machines. The complex loading machine with continuous rotation of principal strain axes is described. Loading represents a superposition of the planar and parallel Couette flows (simple shears) between parallel plates rotated at a certain angular rate. The stress and dilatancy data of quartz sand in deformation on the designed equipment are reported. It is found that stresses and dilatancy in cyclic deformation tend to stationary values. The stationary values of dilatancy increase with increasing shearing strain. The stationary deformation stresses change periodically, their average values weakly depend on the cyclic strains and their amplitude increases.

The article presents a real case of twin tunnels T4 of the East-West Highway (Algeria) for studying purpose of the effects therein on the soil-structure interaction and the excess pore water pressure on the same by use of a numerical analysis PLAXIS 3D. The results obtained from the Mohr-Coulomb model have been compared with those of Hardening Soil Model for drained and undrained condition. More to the point, it indicates that the soil under undrained condition can produce a significant modification in the normalized internal forces and the moment of lining for the stiff tunnels compared to flexible tunnels.

The authors describe numerical modeling of a growing fracture created between two parallel boreholes in an isotropic medium in the nonuniform stress field. The fracture paths are modeled at various deviations of the initial fracture from the axes of boreholes, spacing of the boreholes and the compressive stress field between them. Physical simulation of hydraulic fracturing is implemented using large-size samples.

A series of laboratory cutter indentation tests were conducted on mudstone samples to study the influence of thermo-mechanical coupling on rock fragmentation. The experimental results show that many micro cracks and pores are formed in the crushed zone of rock sample due to the frictional heat during cutting process. After that, the relationships between specific energy and mesoscopic surface of mudstone samples were analyzed. The results show that the thermo-mechanical coupling is conductive to rock fragmentation. Therefore, thermo-mechanical coupling action in the tunneling process greatly improves the rock breaking efficiency. This study is conducive to extend cutter life, reduce project cost and construction risk in TBM tunnel project.

The authors discuss the application ranges of internal overburden dumping open pit mining. Specifics of internal overburden dumping on gently and steeply dipping beds is given. Internal overburden dumps are classified. The methods and techniques of scaled-up internal overburden dumping by means of efficient utilization of mined-out pit area are identified. The ecological safety of dumping is addressed.

The authors focus on feasibility of reducing deformation of surrounding rock mass around underground structures by means of advanced reinforcement of tunnel headings in claystone. The reinforcement efficiency is estimated in 3D calculations. The factors to influence deformation in rock mass ahead of tunnel faces include: rock bolt length, rock bolting system stiffness and the bolt pattern. An additional factor of concern is the mechanical characteristics of claystone. The implemented research shows the highest influence is exerted on deformation in rock mass by the bolt pattern and the rock bolting system stiffness. The efficient design of advanced rock bolting is determined.