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New characteristics and generalized geostructural, isotope-geochronological, and paleomagnetic data are presented for the first time for the territory of Jeannette Island in the De Long Archipelago. Until recently, this small rock outcrop in the East Siberian Sea, discovered in the late 19th century, has been in effect a blank spot on the geological map. Field work made in 2013 and subsequent laboratory analysis of the obtained sample collection show that the island has a volcanosedimentary section including many thin (up to several meters) dolerite dikes. These dikes are the main target of the study. Newly obtained 40Ar/39Ar isotope-geochronological data indicate that the earliest dike intrusion stage corresponds to the Ediacaran (553.6 ± 10.3 Ma). Several subsequent tectonothermal events can be inferred until and through the Early Carboniferous, which affected the stability of the isotope system in the dolerites. In addition, paleomagnetic data confirm at least one more stage of dike emplacement, in the Early Ordovician, as the coordinates of the virtual geomagnetic poles for the dikes are nearly identical to those of the Ordovician paleomagnetic pole determined for carbonate rocks of Kotelny Island. The study describes the main petromagnetic characteristics and magnetic mineralogy of the studied dolerites, validating the primary thermoremanent nature of the identified characteristic component. The results agree with available information on the paleomagnetism, tectonics, and paleogeography of the New Siberian Islands.

This paper studies the chaotic dynamics of two cylindrical shells nested into each other with a gap and their reinforcing beam, also with a gap, which is subjected to a distributed alternating load. The problem is using methods of nonlinear dynamics and qualitative theory of differential equations. The basic equations are the Novozhilov equations for equations geometrically nonlinear structures. Contact pressure is determined by Kantor's method. Using finite elements in the spatial variables, the partial differential equations for the beam and shells are reduced to the Cauchy problem, which is solved by explicit integration (Euler's method). The chaotic synchronization of this system is studied.

The combustion products of solid rocket fuels at a pressure of 40 atm have been studied by molecular beam mass spectrometry. A facility with a four-stage molecular beam formation system has been designed. The possibility of quantifying the composition of combustion products is shown using as an example a composite fuel based on ammonium dinitramide and polycaprolactone.

Five variants of calculating the burning rate of a solid propellant as a function of the pressure in a solid-propellant rocket motor are considered. Two variants of analytical expressions are proposed for approximating real dependences. In all variants, the pressure in the rocket motor can be presented by simple analytical expressions as a function of solid propellant parameters, charging conditions, and structural factors of the charge and motor.

The combustion and chemical transformation of highly exothermic MoO₃/NiO/Al/C and MoO₃/NiO/Al/B mixtures on the surface of a titanium base under the effect of centrifugal acceleration are studied. It is shown that chemical reactions occur not only in the combustion wave, but also on the surface of the titanium base, between the combustion products and the base material (titanium). The dynamics and mechanism of formation of layered (gradient) titanium-ceramics materials (Mo-Ni-C-Ti or Mo-Ni-B-Ti) is investigated.

Composite materials based on Nb with functional (Si, C, B) and alloying dopants (Hf, Ti, Al, etc.) are promising materials for aircraft engine applications. Our previous studies have shown that such composites can be synthesized in the autowave mode (combustion mode) using highly exothermic mixtures of Nb₂O₅ with Al, Si, Hf, and Ti. It has been found that in the combustion wave, Hf actively participates in reducing Nb₂O₅, which complicates its introduction into the composite material, and also leads to an excess of Al in the alloy. In the present study, we have investigated the possibility of replacing Hf in the starting mixture by less active HfAl₃ and have also determined the effect of dispersion of HfAl₃ on the Hf content in the composite material.

Propagation of a plane detonation wave in a stoichiometric mixture of a gas and aluminum particles in a plane channel with a linear expansion section is studied by methods of numerical simulation. The slope of the wall is varied from 15 to 60^o. The basic modes of detonation propagation are analyzed: supercritical (without failure), critical (with partial failure and re-initiation), and subcritical (with complete separation of the shock front and combustion front and with detonation failure). The detonation configuration formed in the expanding section can be a cellular structure with large differences in cell sizes at large angles of expansion or a close-to-uniform structure at the wall angle of 15^o.

This paper reports the experimental and theoretical studies of the synthesis and behavior of a cocrystal energetic material 2,4,6-trinitrotoluene/1,3,5-trinitrobenzene (TNT/TNB). The performance tests show that this material is more powerful and less sensitive than TNT and TNB. A molecular dynamic simulation is conducted for the cocrystal TNT/TNB by using a COMPASS force field with an NPT ensemble. The density function theory is applied to investigate the band structure and the density of states for various pressures and temperatures. The results show that the TNT/TNB crystal is sensitive to pressures in the interval of 35-50 GPa, and the melting temperature of the crystal is around »320 K, which agrees well with experimental results. The Hirshfeld analysis is carried out to ascertain weak interactions and associated two-dimensional fingerprint plots. The crystal packing is demonstrated to be ensured by H × O, C × O and O × O contacts.

This paper presents the results of numerical simulation of the Zaretskii's experiments on the loading of natural uranium in the temperature range 27-862^o in the phase-transition region. Simulation of these experiments is of interest because of the observed features of spall fracture of uranium in the phase-transition region. Spall fracture and compaction was simulated using the DRK-L model of the dynamics of growth and compacting in a liquid medium, which takes into account the effect of strength properties, pressure, surface tension, viscosity, and inertia forces on the growth and collapse of pores. The calculations are carried out according to the UP program - a Lagrangian technique for calculating deformation problems of continuum mechanics in a one-dimensional approximation.

This paper describes the experimental study of dielectric relaxation in energy condensed systems based on etherurate rubber plasticized by glycerin trinitrate and ammonium perchlorate, octogen, and aluminum powders in the frequency range of the electric field from 40 to 1.2 × 10⁹ Hz. Depending on the frequency of the field, it was possible to determine relaxation processes caused by dipole polarization, the bulk electrical conductivity of a polymer binder, and the influence of the surface of aluminum particles.