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The taxonomic composition and distribution of Boreal Carnian ammonoids from northeastern Asia and Arctic Canada have been clarified, the generic assignment of some species has been revised, and their definitions have been standardized. A qualitative comparative analysis of ammonoid assemblages from northeastern Asia and the Canadian Arctic Archipelago has been conducted for the omkutchanicum, armiger, pentastichus, and combined yakutensis and bytschkovi phases. The presence of ammonoids of the genus Boreotrachyceras in the early Carnian of Arctic Canada has been substantiated. This has allowed for the first comparison of coeval ammonoid assemblages of the omkutchanicum phase from northeastern Asia and Arctic Canada, demonstrating the commonality of the ammonoid generic composition of this time throughout the Boreal Realm. It has been established that the early Carnian ammonoid fauna of northeastern Asia differs from that of Arctic Canada by the presence of Tethyan genera (Trachyceras, Striatosirenites) and families (Arpaditidae). A comparative analysis of the ammonoid fauna of the late Carnian has been conducted for the first time, separately for the formation time of the Arctosirenites canadensis beds, equivalent to the pentastichus phase, and for the formation time of the Jovites borealis beds, equivalent to the yakutensis and bytschkovi phases. As a result, for the first time, with phase accuracy, the time of penetration of Tethyan genera into the paleobasins of the Yukon and Arctic Canada (the time of formation of layers with Jovites borealis) was determined, and the belonging of Arctic Canada to the Tethyan Realm was substantiated.

Zones of hydrothermal vein-disseminated, disseminated sulfide, predominantly pyrite, mineralization in Riphean rocks of the Kyvvozhsky region are characterized by elevated contents of Au, Cu, Se, Mo, Ag, Pb, Bi, Sb, Zn. According to the results of the correlation analysis, the following groups of ore elements were identified, within which the strongest positive correlations were established: Ag-Bi-As-Со; Pb-Cu-Zn-Se; Co-Ni-As. Pyrite, arsenopyrite, chalcopyrite, galena, sphalerite, cobaltite, monazite, xenotime, bornite, and covellite are found in association with pyrite in sulfide veinlets. Native gold is rare; particles with peripheral low-grade zones alternate with high-grade gold overgrowths are present. Inclusions of pyrite, pentlandite, monazite, and albite are observed. The gold contains Ag, and sometimes Cu and Pd, as impurities. Judging by the relationships between the minerals, pyrite was the earliest, followed by pyrrhotite, chalcopyrite, and cobaltite, followed by sphalerite, galena, and gold. The formation of sulfide mineralization is associated with hydrothermal processes that occurred in pre-Middle Devonian times, associated with the activation of tectonic-magmatic processes. Geological data, the heavy isotopic composition of pyrite sulfur with a variation in δ³⁴S values from +15.8 to +23.6 ‰, suggest that the most important role was played by regional metamorphic processes that facilitated the mobilization and migration of hydrothermal solutions along faults with the borrowing of various components from the host rocks and subsequent crystallization of sulfides and gold. In some cases, the presence of Cu and Pd impurities in gold indicates a possible influence on the mineral-forming solutions of basic rocks or their partial depth nature as derivatives of basite-hyperbasite magmatism. The Kyvvozhsky district is of interest for primary gold deposits and merits continued exploration.

A method based on a genetic algorithm and a reaction rate equation is proposed to determine the parameters of the Lee - Tarver trinomial ignition and growth model for explosives. The method involves extracting characteristic points from the experimental pressure-time curve. The physical flow data is then analyzed and processed using a proprietary program implementing the genetic algorithm, and the Lee - Tarver model parameters are calibrated. The results show that the calculated pressure curve obtained using the model parameters determined by the genetic algorithm is in good agreement with the curve calculated using reference parameters. The maximum error for peak pressure is 6.3%, demonstrating the high accuracy and efficiency of the proposed calibration method.

In self-propagating high-temperature synthesis processes, one of the key issues is the availability and reproducibility of the combustion mode. It is well known that different grades and even different batches of the same grade of powder metals, incorporated during synthesis and obtained from particles of different shapes and sizes, contain varying amounts of gasifiable impurities. Therefore, the combustion rate of powder mixtures of the same composition produced from them can vary severalfold. Previously, the authors of articles for a granulated mixture of 5Ti + 3Si, and in this study for Ti + C mixtures, determined the combustion rate of mixtures with titanium of a single grade in narrow fractions for wide particle sizes of the original titanium powder. These values are well approximated by power laws with a determination coefficient of R² > 0.97. The resulting approximating dependences are presented as baselines. These dependences were used to compare the combustion rates of other titanium grades. For subsequent narrow fractions of other titanium grades, the combustion rate components of powder and granulated mixtures of 5Ti + 3Si, Ti + C were analyzed. Experiments show that the basic dependences of combustion rate on titanium particle size allow us to predict the combustion rate of granulated SHS mixtures of the same composition for narrow fractions of other titanium grades with a level of at least 30%.

The influence of the component ratio, mechanical activation and preliminary compression of the samples on the burning rate and elongation of uncompressed samples during synthesis, on the phase composition and morphology of the combustion products in the (5Ti + 3Si) + (Ti + 2B) system was studied. The combustion front did not reach the lower end of the sample from the initial 5Ti + 3Si mixture. Preliminary compression of the sample, as well as mechanical activation of the 5Ti + 3Si mixture, or the addition of a Ti + 2B mixture allowed the sample to burn to completion. The burning rate and elongation of samples from (100 - x)(5Ti + 3Si) + x(Ti + 2B) mixtures increased after mechanical activation. A tendency towards a decrease in the burning rate with an increase in the 5Ti + 3Si content in the mixtures was recorded. The combustion rate of samples from mechanically activated mixtures increased after compression and remained virtually unchanged for the initial mixtures (except for the Ti + 2B mixture). For some initial mixtures, shrinkage of the product samples was observed after preliminary compression. The maximum combustion rate was measured for samples containing 20% of the 5Ti + 3Si mixture. The dependence of the elongation of samples from the initial (100 - x)(5Ti + 3Si) + x(Ti + 2B) mixtures on their composition exhibited extremes. The phase composition of the combustion products remained unchanged after compression of the samples and mechanical activation of the mixtures.

The effect of preliminary mechanical activation (MA) of carbon black powder on the properties, compaction, and combustion patterns of Ti + C mixtures in an equiatomic ratio of components was studied. It was shown that during the MA process, the arched structure is destroyed and agglomerates of carbon black particles are crushed, which leads to an increase in bulk density by more than three times. It was found that during compaction, carbon black powder behaves as a solid non-plastic material with a high elastic aftereffect (up to 14%). It was shown that in Ti + C mixtures above a relative density of 0.52, a framework of titanium particles is formed, which is responsible for the strength properties of the compacts. It was found that compaction of Ti + C mixtures to a pressure of 50 MPa corresponds to the stage of structural deformation, and above this pressure, the stage of elastic-plastic deformation begins. It is shown that the relative density of compacts from Ti + C mixtures at the onset of the elastic-plastic deformation stage depends on the degree of MA of the carbon black powder. At the same pressure of 50 MPa, mixtures with more dispersed carbon black compact to a higher relative density of 0.65. It is shown that the dependences of the combustion temperature of compacts made from Ti + C mixtures on pressure and density have maxima. Increasing the density of Ti + C mixtures at the structural deformation stage (pressure up to 50 MPa) ensures an increase in the contact surface between the reactants and, consequently, an increase in the combustion temperature. With a further increase in compaction pressure at the beginning of the elastic-plastic deformation stage, the increase in the contact surface between the titanium particles leads to a decrease in the combustion temperature. It was found that the absolute value of the combustion temperature peaks increased with increasing density: for the mixture with the original soot, T_max ≈ 2900 °C at a relative density of 0.58; for the mixture with soot after 3 hours of MA, T_max ≈ 3000 °C at a density of 0.63; for the mixture with soot after 20 hours of MA, T_max ≈ 3200 °C at a density of 0.65. With increasing pressing pressure, the combustion rate decreases due to deterioration in the conditions for removing impurity gases from the volume of the original compacts. The appearance of delamination cracks is shown to lead to a sharp increase in the combustion rate.

An experimental study of the electrical resistance of copper foil under repeated shock compression up to a pressure of 40 GPa was performed in several explosive systems: in a reflected shock wave, under compression in a rigid cage, and in a layered system producing a sequence of waves of increasing amplitude. An improved measuring cell design is proposed, significantly reducing the influence of parasitic eddy currents on the recorded voltage. Under shock compression, the electrical resistance of copper increases monotonically, but the rate of increase depends on the loading history. Under compression by a sequence of shock waves, the electrical resistance of the metal is lower than under compression by a single shock wave (at the same incident wave pressure in a dielectric cage). In this case, the main change in copper's electrical resistance occurs in the first shock wave. In subsequent waves, the electrical resistance also increases, but the final value is lower than in a single shock wave. An assessment of the concentration of defects in the crystalline structure of a copper specimen under complex loading was performed. With repeated compression, the defect concentration is lower than with a single compression (at the same wave pressure or deformation). This means that under complex shock loading, defects are generated predominantly in the early stages of compression, with only a relatively small increase in the number of defects occurring subsequently. Qualitatively, the defect concentration during complex shock loading is determined by the deformation of the material in the first shock wave.

Based on the interpretation of high-resolution seismoacoustic profiles and borehole drilling data in the Barents and Kara Seas, a GIS database was developed, and a digital map of the distribution and depth of the top of submarine permafrost in the Barents and Kara Seas was constructed. In the southwestern and northeastern parts of the Kara Sea, the submarine permafrost boundary partially coincides with the morphostructure of the denudation-tectonic slope of the seafloor. Three regions with significantly different depths of the top of the submarine permafrost were identified on the shelf. On the Barents Sea shelf, the average depth of the submarine permafrost top is (13.3 ± 6.6) m; in the southwestern part of the Kara Sea, (16.7 ± 8.1) m; in the northeastern part, (29.5 ± 15.5) m. The average rate of the subsidence of the submarine permafrost top in the Holocene is 8.2 mm/yr for the Barents Sea and 5.5 mm/yr for the Kara Sea.

The application of capacitive resistivity surveying in conjunction with other methods of geotechnical monitoring of oil and gas gathering pipelines in the permafrost zone is considered to improve monitoring efficiency and informativeness. It is established that electromagnetic surveying is efficient to map frost-susceptible soils because of the dependence of electrical resistivity on the soil pore water content. The use of electrical resistivity allowed the identification of low-resistivity sections along the pipeline, where active frost jacking of the piles occurs. The proposed electrical surveying at shallow depths is effective to identify areas of frost-susceptible soils when used as part of an integrated geotechnical monitoring program.

Spatiotemporal changes in the rate of thermoabrasion of the shores of the East Siberian Sea have been studied on the basis of measurement data and formulated zero-dimensional and one-dimensional mathematical models. The results indicate that the rate of thermoabrasion of ice-rich coasts in the western part of the sea decreases from south to north. The reason for this is a decrease in the duration of thermal abrasion northward because of the negative meridional air temperature gradient during the ice-free period. The zero-dimensional model indicates that climate warming with an increase in air temperature of the ice-free period by 1 °C increases the rate of thermоabrasion of the shores by 1.84 times independently from the latitude of the studied coastal areas. According to the one-dimensional model, the influence of positive air temperatures on the development of coastal cryogenic processes decreases at higher latitudes. As a result, the response of ice-rich coasts to changes in air temperature of the ice-free period weakens by three times in the northern part of the coast compared to the southern part.