Home – Home – Jornals – Siberian Journal of Forest Science 2025 number 4

This paper presents new geochronological and paleomagnetic data that support the idea of later termination of magmatism in the Okhotsk-Chukotka Volcanic Belt (OCVB) within the East Chukotka flank zone than previously thought. It also allows the calculation of a new paleomagnetic pole (78.6°N, 212.2°E, A₉₅ = 4.7°, N = 104) with an age of ~72 Ma for the vicinity of the Valunistoe deposit. Combined with paleomagnetic data previously obtained by us for the Kupol deposit area, the new results lead to the following conclusions: 1) the studied areas (the Kupol and Valunistoe location) have experienced relatively small, but statistically significant, displacements relative to the North American plate during the time interval from the late Cretaceous to the present. 2) The Kupol location is rotated counterclockwise by several to a few tens of degrees relative to the North American plate, while the Valunistoe location is displaced relative to this plate in latitude by a distance of at least several hundred kilometers. 3) Based on the obtained data, we propose a model, building on the existing Bering Sea region model of Redfield and Fitzgerald [1993], according to which the Kupol and Valunistoe locations belong to the boundary area between the North American plate and the Bering plate, represented by a series of tectonic blocks. The tectonic block to which the Valunistoe location belongs is one of the westernmost blocks grouped into the Bering plate, while the Kupol location belongs to the easternmost regions of the Chukotka deformed margin of the North American plate. Deformations arising in the interaction of these tectonic blocks in the region under consideration are mainly diffuse. The Trans-Bering Seismic Belt appears to be a potential area where the discussed deformations may be most concentrated.

Results of deep seismic studies based on P- and S-wave data on a 500-km Sikhote-Alin fragment of the 8-DV reference geophysical profile are presented. Deep seismic sections of the upper crust (to depths of 15-20 km) with distributed longitudinal and transverse wave velocities are constructed. The P-wave velocity over most of the Middle Amur Basin and the East Sikhote-Alin volcanoplutonic belt varies from 4-5 km/s in the uppermost section to 5.8-6.3 km/s at depths of 7-15 km. The Sikhote-Alin orogenic belt in the section along the profile is represented by an anticlinal structure with high-velocity (up to 5.5-5.8 km/s) rocks uplifted in the center; at great depths of 10-20 km within its limits, the P-wave velocities reach 6.1-6.3 km/s. In the top of the section, the S-wave velocities within the profile as a whole are 2.7-2.9 km/s. Lower values (2.6-2.8 km/s) are observed in the center and east of the Middle Amur Depression and the eastern section of the East Sikhote-Alin volcanoplutonic belt. Higher velocities up to 3.35 km/s are observed in the central Sikhote-Alin orogenic complex. At depths of 5-15 km within the section, the S-wave velocities increase up to 3.4-3.65 km/s. The heterogeneous structure of the top of the Earth’s crust to depths of 15-20 km was identified using the P- and S-wave velocities, their ratio, and Poisson’s ratio. The profile section was used to analyze a relationship between the identified anomalies and the location of large mineragenic zones in Russian Manchuria. The correlations established earlier on the 2-DV, 3-DV, 1-SB, and East Stanovoy fragment of the 8-DV profile are confirmed using the confinement of many ore deposits to zones of lower P- and S-wave velocity ratios and Poisson’s ratio in the top of the Earth’s crust. We also substantiated the relationship between the identified surface seismic anomalies and deep (at depths of 5-20 km) roots (intermediate magmatic foci), which can be considered as ore-supplying.

Remains of calcareous cyanobacteria of the genera Garwoodia Wood, 1941, Ortonella Garwood, 1914 and Hedstroemia Rothpletz, 1913 (Garwoodiaceae family) were first identified in the late Darriwilian deposits of the Moyero River section (Eastern Siberia). Ortonella and Garwoodia were previously found on the Siberian Platform only in Silurian deposits, making this the earliest discovery of representatives of these genera in the region. Ortonella and Garwoodia dominate, whereas Hedstroemia occupy a subordinate position in stromatoporoid-cyanobacterial bioherms. Only Ortonella was found in biostromes and shell interlayers of the bivalve banks. The sediments in question accumulated in the shallow-water lagoonal environment. The latter determined the failure of skeletal metazoan organisms to become the main frame builders of biostromes and bioherms, despite the global increase in biodiversity during the Great Ordovician Biodiversification Event (GOBE). Their role was taken over by cyanobacterial communities, which proved more resistant to such environmental conditions. The increase in phosphorus content in bottom sediments apparently triggered the development of cyanobacteria; which probably caused a local paleoecological crisis of the benthic fauna in this part of the paleobasin. The latter is confirmed by the depleted ostracod assemblage in the Moyero River section (in contrast to coeval deposits of the Lena, Podkamennaya Tunguska, and Kulyumbe river sections). The decline in biodiversity of benthic fauna and, particularly, of skeletal metazoan frame builders during cyanobacterial “blooms” may be explained by the impact of cyanotoxins, which are destructive to marine life. The data obtained demonstrate that even in the age of global biotic expansion of the Ordovician period, local conditions could limit the contribution of skeletal metazoans to reef construction, maintaining the dominance of microbial communities.

A recent revision of the volume and the age of the Nemakit-Daldynian Stage of the Upper Vendian articulated its comprehensive (bio- and chemostratigraphic) characteristic. This stage includes strata ranging from the first appearance of unequivocal anabaritids (approximately 539 Ma) to the base of the Nochoroicyathus sunnaginicus Assemblage Zone of the Lower Cambrian Tommotian Stage (530 Ma). In addition to the characteristic assemblages of small shelly fossils (SSF), this stratigraphic interval is defined by specific changes in the trace fossil assembalges and by variations of carbon isotope composition in carbonates. Using the established criteria, this study evaluates the completeness of the Nemakit-Daldynian Stage in its type locality (western Anabar Uplift) and in other sections of the Siberian Platform (eastern Anabar Uplift, Olenek Uplift, Kharaulakh Uplift, Uchur-Maya Region, Patom Basin, Baikal area, Irkutsk Cis-Sayans Uplift, Biryusa Cis-Sayans Uplift, southern Yenisei Ridge, northern Yenisei Ridge, Turukhansk Uplift, Igarka Uplift, and inner regions of the Platform).

The impact facies are subdivided into coptogenic (primarily deposited) and coptomict (redeposited) units. The redeposited impact facies have been poorly studied. In this work, the deposits of the coptomict facies are characterized in detail for the first time by the example of the Kara astrobleme. The structures and textures of impactites are examined at the macrolevel, and the structural and compositional specifics of the components (lithoclasts, vitroclasts, and matrix) of lapilli and agglomerate suevites of the Sayakha River area have been described at the microlevel. The reconstruction of the past events has shown that the clastic impactites of the northwestern rim of the Kara astrobleme formed under conditions of landslide from the crater lip at the stage of the early modification of the astrobleme. The results obtained can be used to construct a model for the formation of the Kara impact structure and to improve the unified model for the formation of clastic impactites of the coptomict facies in a large meteorite crater.

The Anakit intrusion had a multistage effect on the host sediments, manifested as spurrite-merwinite metamorphism, early retrograde processes and associated formation of a uniquely diverse Cl-silicate mineralization (with a Cl content of up to 7-15 wt.%), skarn formation, and low-temperature hydrothermal processes. At the eastern contact of the Anakit massif, high-temperature spurrite-merwinite marbles were studied and characterized. The major and trace element and mineral composition of the rocks and the compositions of all rock-forming, accessory, and retrograde minerals has been determined. Under peak metamorphic conditions, the temperature in the near-contact zone (0.3-5 m) exceeded 900 °C, and X _CO2 reached 0.3. The δ¹³C-δ¹⁸O trend determined for the first time is similar to those at contacts with a minimum metasomatic influence. The small difference between the δ¹³C and δ¹⁸O values of the Anakit marbles and their protoliths (Δδ¹³C ≤ 2.0‰ and Δδ¹⁸O ≤ 4.0‰) proves the predominant contribution of metamorphic decarbonation to carbon and oxygen isotope fractionation. Along with mineral indicators, it testifies to the limited infiltration of magmatogenic fluids into the host strata.

We report the results of lithological and mineralogical studies of Holocene bottom sediments from the hypersaline Lake Bolshoe Yarovoe (salinity 150 g/L), located on the territory of the Kulunda steppe (south of Western Siberia). Research methods: X-ray diffractometry (XRD), IR spectroscopy, laser grain-size analysis, elemental analysis, and radiocarbon dating. The thickness of the uncovered sediments is 483 cm. Terrigenous minerals throughout the section are represented by quartz, plagioclase, and layered silicates (mica, chlorite, smectite, and kaolinite). The variable amounts of omnipresent authigenic minerals include halite, gypsum, carbonates, and traces of pyrite. We identified Mg-calcites with different Mg contents and aragonite using the mathematical modeling of X-ray diffraction patterns in the assemblage of carbonate minerals. The mineralogical and crystallochemical studies of sediments supplemented by the results of other analyses have provided information about the evolution of the climate of the Kulunda steppe in the Middle to Late Holocene. The comparatively arid regional climate of the Middle Holocene became more humid in the first half of the Subatlantic, but aridization signs reappeared in the section about 600 years ago (Little Ice Age).

Maxwell’s equations and the equations of two-velocity hydrodynamics of saturated porous media are consistently combined in the absence of local thermodynamic equilibrium. Equations describing relaxation of dielectric polarization vector are inferred. The law of dielectric permittivity dispersion is established in the presence of two interacting relaxation processes: relaxation of the difference in hydrodynamic velocities and relaxation of dielectric polarization. Relationship between kinetic coefficients and complex dielectric permittivity is shown, particularly relationship with hydrodynamic permeability of porous medium. A method for determining the hydrodynamic permeability of a porous medium, which does not take into account the relaxation time distribution function, based on knowledge of the dielectric spectrum was developed. Medium’s dielectric response to external inductive effect is examined for wells in saturated porous media.

The efficiency of using a neural network for detecting "point" objects whose shape is determined by the characteristics of the recording optical-electronic channel in images with a spatially nonstationary background is studied. The training data sets take into account the diversity of background situations and the variability of the shape of the signal from objects due to their movement. The results of detecting objects of different brightness and colors on real background images obtained during observation of the Earth's surface from a geostationary orbit are presented.

Reflectometric measurements of the ice surface conditions of reservoirs in the Krasnoyarsk Krai and the Republic of Khakasia are conducted using radio signals from navigation satellites emitting in the L1 band. During processing of the resultant reflectograms, mathematical processing of the amplitude-time dependencies is applied using the fast Fourier transform method, allowing for the experimental determination of ice cover thicknesses with various macrophysical characteristics.

Functionally defined surfaces with a complex microstructure are offered for realistic scenes. A model based on wave optics is described for visualizing surfaces with microscale roughness, which increase the realism of objects under various observation and lighting conditions because of diffraction and mutual interference. The model includes modeling of light transfer and surface, which serve as its initial data. The diffraction effects taking into account the surface roughness are shown. An approximation of spatial coherence using a Gaussian filter is considered; as a result, it is possible to visualize not only the glare, but also the diffraction of higher orders.

Under fluctuating meteorological parameters of the atmosphere (temperature, humidity, etc.), the infrared image can dynamically change its contrast and brightness characteristics. This leads to the fact that the morphological imaging pattern of the detected object is subject to changes. The main reason is the inhomogeneity of the atmosphere, which affects the propagation of infrared radiation from the source to the thermal camera, as well as the profile of the object, which characterizes its heat distribution in the field of view of the infrared imager. In this paper, we search for stable features of the morphological imaging pattern for automatic pattern recognition in the middle wavelength infrared range (3-5 μm) relative to the weather conditions and object profile. It is shown that the feature of the middle infrared contrast, which is the difference between the warmest elements of the object and the image background, is an invariant characteristic that can be used in automatic target recognition problems. The results of the experiment for vehicles demonstrate the effectiveness of this parameter relative to changing temperature and humidity of the environment. However, the profile of the object can distort the “stability” of the middle infrared contrast due to the geometric arrangement of the heat-carrying vehicle elements.

The problem of estimating the phase coordinates of an object whose motion is described by a system of differential equations is considered. The Kalman filter equations, derived from the solution of the generalized Stratonovich equation in the Gaussian approximation, are used for the estimation. The generalized Stratonovich equation allows one to consider cases where a multidimensional image of the object being observed is used as an observation signal, i.e., a scalar function of an arbitrary number of variables reflecting the specifics of the observation device. It is shown that the dataset from the multiple observation devices used is included into the generalized Stratonovich equation and the Kalman filter equations as an additive combination of the time derivatives of the likelihood functionals of each individual observation device. Moreover, each of these functionals can account for the correlation of observation noise.

Effective elimination of cyber threats involves detecting attacks and taking protective measures in real time based on streaming data, but existing solutions are not always able to process data in this mode. To solve these problems, it is proposed to use the incremental learning method - fuzzy classification and clustering systems of the Angelov-Yager first-order type. The original implementation of the system uses the Cauchy kernel function; the use of alternative kernel functions has not been considered before. An experimental study of alternative kernel functions on cybersecurity data sets is conducted, a statistically significant difference in the accuracy and number of rules in the application of various functions is revealed, and the best kernel functions for individual data sets are identified

Due to its high productivity and demand for products, the oil industry occupies a special place in the modern industry. Increased attention is paid to monitoring its condition and the performance of the exploited areas. Exploration of new fields and drilling of producing wells require a lot of time and financial costs. To reduce them, advanced technologies are currently widely used, including various artificial intelligence methods, for example, to assess the percentage of fractions in the oil flow from the well. The paper presents the results of studying a number of models based on neural networks of different architectures for predicting the flow rate of components of a multiphase flow from a well. To conduct the study, data received from sensors of multiphase flow meters based on a Venturi pipe and an X-ray flow meter are used.

The paper presents the development of an automated control system for the experimental equipment of the station 1-3 "Fast-flowing processes" of the Center for Collective Use "Siberian Ring Photon Source." The architecture of the control system using open software components and protocols is described. Particular attention is paid to the implementation of the engineer's workstation interface as a web application that provides access to the equipment control and configuration. The key software modules of the server and client parts of the web application are considered. The proposed solution ensures scalability, fault tolerance, and uniformity of the software architecture at all levels of the system.

This paper is devoted to the problem of increasing the fault tolerance of control PLC programs developed on the basis of the process-oriented approach. This paper considers the problem of multiple access conflicts that arise in process-oriented programs when implementing mutually exclusive operations on a separate actuator. The causes of such conflicts are analyzed, and a modification of the mathematical model of a process-oriented program is proposed, which allows elimination of such conflicts in a constructive manner. The resolution of the considered class of conflicts, on the one hand, increases the fault tolerance of control programs and, on the other hand, has no side effects, thus, eliminating the need to change the general structure of the program. To implement the modified model, an extension of the syntax of the poST language is proposed.

A constructive method is proposed for the multi-criteria optimization of nonlinear objects in technological thermal physics. It involves the evaluation of the accuracy of approximation to a given temperature state in numerical modeling of thermo-diffusion fields using a uniform metric. It is clear that the structure of the program control is identical to that previously found for linear models of controlled processes. The technology developed in previous works for solving multi-criteria problems in linear systems with distributed parameters is extended to the nonlinear objects under study. This is done under conditions of selecting time-constant values of special control in the corresponding sections. This is quite simple to implement in such an approximation of program control action on digital models of the controlled variable. The capabilities of the proposed approach are illustrated by an example of independent interest: the numerical solution of the problem of optimizing the induction heating process according to three basic indicators of technical and economic efficiency using a specialized electro-thermal model of the temperature field described by nonlinear heat conduction equations.

This paper presents a Brillouin optical time-domain analysis (BOTDA) system based on a self-sweeping laser. The system interrogates a 50 km optical fiber with a frequency error of 1.5 MHz within a 30-second measurement time. Furthermore, it is demonstrated that the sensing range can be extended to 88 km and 96 km using standard and correlation-based signal processing methods, respectively.

An installation based on a Q-switched Cr:Yb:Ho:YSGG (λ = 2.87 μm) 15 mJ, 40 ns laser is described. The installation is intended for laser damage threshold measurements of 3-μm range optical items and other laser -matter interaction experiments. The peculiarities of laser caustic measurements near the focal plane of an ƒ = 50 mm lens with the aid of the scanning knife method for different temporal structures of the radiation pulse are discussed. At the laser beam diameter of »160 μm, the radiation energy density on the surface of the optical item under investigation can be smoothly varied in the range from 1 to 52 J/cm².

The paper presents an approach to controlling surface plasmon polaritons (SPP) by diffraction on acoustic waves. The Bragg diffraction of the SPP on an ultrasonic beam directed along the interface between media, one being an isotropic dielectric, is considered. It is shown that, in addition to the formation of SPP beams of zero and first diffraction orders, the SPP will also be converted into bulk radiation. Formulas for the intensities of SPP beams of zero and first diffraction orders for the main diffraction modes are derived. The proposed method can be used in the development of modern information processing devices, as well as devices for non-destructive testing of the homogeneity of dielectric coatings on metal surfaces.

In this work, we investigate the response time and sensitivity in the visible spectral range of a commercial pyroelectric detector based on the organic crystal tetraaminodiphenyl MG-32 (JSC NSDE Vostok) with a 0.5 mm thick polypropylene input window. The sensor time constant is varied by connecting the capacitance C in the range from 2 nF to 3.8 μF to the feedback circuit of the receiver amplifier. With an increase in the capacitance in the range of 0.1 - 3.8 μF, the receiver time constant increases linearly from 0.2 to 5 ms; at lower capacitances, it reaches saturation, setting a limit of ≈ 25 μs. The voltage sensitivity is tested using diode laser radiation (λ = 637 nm), which at C = 0.1 μF is 3600 V/W, which is 8% smaller than the sensitivity of the receiver without a polypropylene window. The equivalent noise power and detectability are practically independent of the feedback capacitance in the range C = 0.002 - 0.1 μF and are approximately 1-2 orders of magnitude superior to the characteristics of other commercial pyroelectric detectors and the Golay optoacoustic cell in the visible range, which makes the receiver under study quite promising and universal for many applications.

This study investigates a friction stir welding process for joining high-strength aluminum alloys. By implementing an active liquid cooling system and a post-weld aging treatment, a weld strength equivalent to the base material is achieved. The effect of cooling intensity on the microstructure and mechanical properties of the welds is examined. Optimal welding parameters for producing equal-strength joints are identified.

This study investigates the contact interaction between a thin composite strip and the rolls during rolling, focusing on conditions that ensure a horizontally straight exit end. The values of friction coefficients required to maintain a straight exit end during asymmetric rolling of a multilayer metallic material are determined. A finite element modeling of asymmetric rolling of a five-layer composite is performed with varying friction coefficients on rolls. The tool-workpiece interaction is modeled using the Amontons-Coulomb friction law, with the friction coefficient ranging from 0.1 to 0.4. The results show that a friction coefficient of 0.2 on both rolls minimizes the curvature of the exit end, resulting in an almost perfectly straight strip. For this optimal case, the stress-strain state is analyzed and the linear velocity distribution across the strip in the rolling direction is investigated. The analysis suggests that, upon passing across the deformation region, all material points move at a uniform velocity, which is significantly lower than the peripheral velocity of the lower roll, indicating persistent slip of the strip at the lower surface of the roll.

This paper addresses key challenges in the numerical simulation of gas-particle flows relevant to aerodynamics. Results are presented on the flow structure of the dispersed phase and the associated energy flux to a body surface. Particular emphasis is placed on simulating stochastic phenomena, including inter-particle collisions, the scattering of non-spherical particles upon wall rebound, and particle polydispersity, which are characteristic of real flows, but neglected in classical gas-particle flow theory. The collisional gas of particles within the carrier gas is simulated using a kinetic approach coupled with the direct simulation Monte Carlo (DSMC) method. A three-dimensional model for non-spherical particle-wall collision is implemented, and the particle size distribution in the free stream is described by a log-normal law. Using this approach, the dispersed phase flow structure was investigated for high-speed gas-particle flow over a blunt body (specifically, transverse flow around a cylinder). Energy loss distributions upon impact with the surface are calculated for particles of different shapes. The influence of the shielding effect during particle collisions on the energy loss is also examined.

This paper presents a method for predicting the movement of the laminar-turbulent transition front on the side surfaces of spherically blunted circular cones with account for surface roughness effects. The study demonstrates that mass ablation of the composite thermal protection systems on re-entry vehicles induces surface roughness along the flight trajectory. This roughness arises from differential ablation rates between the constituents of the material, such as fillers and binders, reinforcing frame elements, and the carbon matrix.

Non-equilibrium molecular dynamics (NEMD) simulations are performed to investigate the viscosity and rheology of benzene and nanofluids containing carbon nanotubes of two diameters and varying lengths. The results demonstrate that these fluids exhibit pseudoplastic (shear-thinning) behavior with increasing shear rate. Correlations are established for the critical shear rates as a function of nanotube concentration and length. At high shear rates, the viscosity differences between the nanofluids and the base fluid decrease monotonically, irrespective of nanotube length. This is attributed to shear-induced changes in the momentum dissipation mechanisms within the system.

This paper presents combined experimental and numerical results on the interaction of shock waves with highly porous, permeable barriers featuring both homogeneous and inhomogeneous spatial structures. The experiments are conducted in a shock tube for shock Mach numbers ranging within M = 1.2÷1.8. The experimental barriers comprise stacked wire meshes with triangular cells and layers of cellular nickel foam. The numerical simulations are based on the Reynolds-averaged Navier-Stokes (RANS) equations, utilizing a toroidal skeletal model for the porous media. The results demonstrate that minimal shock wave reflection is achieved using graded barriers, which consist of a sequence of mesh layers with progressively decreasing cell size, capped by a layer of fine-pore nickel foam.

This paper presents numerical simulation results for supersonic turbulent airflow in a planar channel with a backward-facing step, incorporating a volumetric heat source that simulates the heat release from chemical reactions. The simulations account for conjugate heat transfer between the flow and copper plates mounted into the channel walls, which act as heat flux sensor elements. The results show that the heat source reduces the flow velocity and causes an upstream shift of the supersonic wave structure. Increasing the source power enlarges the subsonic zone transversely, induced by flow separation at the shock impingement location. A localized subsonic region forms in the flow core, isolated from the near-wall subsonic zone by a narrow supersonic jet, confining the thermal plume to the core flow. A sharp flow restructuring is triggered when the local separation zone merges with the recirculation zone downstream of the backward-facing step, allowing for the gas (warmed up by the heat source) to penetrate the enlarged separation bubble. This narrows the effective flow region, causing a compression wave, rather than an expansion wave, to form at the step edge. Consequently, the core flow temperature decreases while wall heat fluxes increase substantially.

The gas separation process via a membrane-sorption method шs investigated using a hydrogen-helium mixture and silica microspheres. Experimental and numerical modeling of a two-stage membrane-sorption process for hydrogen-helium mixture separation is carried out. The experimental two-stage separation at 22°C demonstrates an increase in the helium volume fraction from 10.5% in the feed to 57.8% after the first stage and 93.3% after the second stage. Evidently, the final helium volume fraction in the enriched stream is primarily influenced by the amount of depleted mixture remaining in the adsorber prior to the desorption cycle.

Quantitative thermography is used to study the effect of streamwise-orientated, quasi-two-dimensional roughness elements (strips) on the laminar-turbulent transition location on a 45° swept wing model under various test conditions. The efficacy of these sliding roughness elements for flow laminarization is investigated under elevated freestream turbulence levels and increased surface roughness. The results demonstrate that this laminarization method is also robust to moderate variations in the freestream velocity.

This paper presents an experimental investigation of how heat release from homogeneous condensation in a supersonic expanding flow affects the density distribution and shock structure of underexpanded rarefied-gas jets. The results demonstrate that this effect is significant for modeling the force and thermal loads imposed by attitude and control thrusters on adjacent spacecraft components.

We present the SUNSHYNE software package, designed for numerical simulation of compressible gas flows on modern high-performance computing systems, including those accelerated by high-performance graphics processing units (GPUs). The package features a graphical user interface and enables simulations in complex geometries for industrial applications. This is facilitated by versatile boundary condition specification, support for unstructured and block-structured grids, and integration with computer-aided design systems. The paper touches upon the implemented physical models, numerical methods, and functional capabilities of the package. Example simulations are provided, including non-equilibrium flows, direct numerical simulation of transition to turbulence, and heterogeneous detonation.

We develop and implement a numerical model for the dynamic fracture of a functionally graded material (FGM) plate based on St.3 steel and VT8 titanium alloy under shock-wave loading. The simulations employ a three-dimensional finite element formulation within the EFES software package. A mixing parameter is introduced to model the smooth transition in material properties across the plate thickness. A Taylor-type numerical test and a simulation of aluminum projectile impact on a graded barrier are conducted to assess residual deformation, pressure profiles, and spall formation conditions. The St.3 → VT8 gradient direction effectively dissipates the shock wave and suppresses spallation, whereas the reverse gradient causes tensile stress localization and spall fragment formation. The numerical spall thickness values show good agreement with experimental data, confirming the model's adequacy for predicting the dynamic strength of functionally graded structures under high-rate loading.

This paper proposes a mathematical model within the class of generalized continua that account for an internal microstructure. The model considers the inhomogeneous deformation of an infinitesimal volume element. It incorporates plastic slips at the interfaces between these volume elements. Unlike classical continuum mechanics, the formulation introduces additional kinematic degrees of freedom. In the planar case, these are represented by two independent smooth displacement fields, which introduce a length-scale parameter into the constitutive equations, characterizing the internal structure of the medium. The model is applied to numerically solve the problem of stress redistribution in the near-field zone of a system of mine excavations in a rock mass, induced by a specific mineral extraction technology. The results demonstrate that accounting for the material microstructure, which is a feature absent in classical elastoplastic models, shifts a significant portion of the load from the excavation boundaries deeper into the rock mass.

This study determines the mechanical parameters of ABS plastic (acrylonitrile butadiene styrene) by subjecting plates of finite thickness (1-5 mm) to impact loading. A spherical lead particle with a mass of 0.45 g serves as the projectile. A series of experiments provides the basis for mathematical modeling performed with the Reactor3D software package. The results show that the 0.45 g spherical projectile perforates a 3.5-mm-thick ABS plastic plate at an impact velocity of at least 230 m/s. The required impact velocity for perforation ranges from 140 to 300 m/s for ABS plates with thicknesses of 1 to 5 mm. The parameters obtained in this study describe the behavior of finite-thickness plates under impact with an error of less than 5%.

This study assesses the potential for replacing expensive alloys with novel metal-matrix composites comprising more accessible materials. It compares the dynamic response of the widely used VT20 aviation titanium alloy with that of a 316L steel - A356 aluminum metal-matrix composite under impact loading.

This study investigates the mechanoluminescent properties of epoxy resin composites filled with SrAl₂O₄:Eu,Dy (SAOED) phosphor. The elastic modulus of this phosphor is measured. The relationships between the mechanoluminescent intensity and mechanical loading parameters are characterized. The composites exhibit repeatable mechanoluminescence under cyclic mechanical stimulation.

This review surveys the development of hydrophobic and anti-icing coatings fabricated by cold gas dynamic spraying. It discusses fabrication strategies for achieving high hydrophobicity and icephobicity with cold gas dynamic spraying, covering coatings based on polymeric, metallic, and ceramic materials. A key advantage of cold gas dynamic spraying is its ability to create coatings with complex microstructures that confer high hydrophobicity and icephobicity without the need for post-processing. The review also covers the fundamental theoretical models of wetting and the key factors governing surface icephobicity.

As part of long-term study conducted in Krasnoyarsk forest-steppe, the dynamics of the increment of major phytomass fractions (stems, roots, branches, needles) of young pine stands formed on former agricultural lands were analyzed. It was found that, in early ontogenesis, the maximum phytomass increment is characteristic for overstocked tree stands with an initial density of 40.7 thousand trees/ha. However, by the age of 17, these stands experience a decline in productivity due to intensified intraspecific competition for resources, which negatively affects photosynthesis efficiency. In contrast, in stands with lower density, including those with thinning treatments, phytomass increment shows a stable positive trend with increasing tree stands of 9-20 age. It was established that under natural competitive conditions, the proportion of stem fraction increment decreases with age, whereas in stands subjected to thinning, its contribution increases, reaching 62 % of total increment over a 20-year period. The obtained data emphasize the necessity of comprehensively considering all phytomass fractions when assessing the capacity of stands to absorb atmospheric carbon dioxide. Thus, accounting only for stem mass increment results in almost a twofold underestimation of the carbon sequestration potential of overstocked young pine stands. The study results should be taken into account when assessing the carbon balance of forest ecosystems in the context of international carbon trading. It has been shown that regulating the density and spatial structure of stands allows optimizing their functional purpose - from creating carbon farms focused on CO₂ sequestration to organizing industrial plantations prioritizing target assortments production. Thus, silvicultural practices, including thinning, serve as a key tool for managing the productivity and ecosystem services of forest stands.