Home – Home – Jornals – Advanced Search

It has been experimentally shown that the flameless combustion of RDX mixtures with iron precursors, nitrogen-containing additives, and a polymer binder can lead to the formation of iron nitrides. Nanosized particles of iron nitride (Fe₃N) were obtained by optimizing the ratio of initial components and conditions of flameless combustion of RDX. The developed method for obtaining iron nitrides can be used to obtain nanosized particles of nitrides of other elements.

The effect of pulsed laser radiation (1064 nm, 120 μs, 10 Hz, 1.5 J/cm²) on coal samples in argon is under study. Mass spectrometry is used to analyze the gaseous products of coal pyrolysis. The dependences of the composition of gaseous pyrolysis products of coal samples and the proportion of reacted samples on their technical and genetic characteristics are established. Data on the yield of combustible gases per unit mass of reacted coal samples were obtained.

For the first time, a comparative study of the combustion of powder and granular mixtures Ti + C, (Ti + C) + 20% Cu with granules of different sizes with varying the particle size of titanium from 31 to 142 μm was performed. It has been found that the combustion rate of the (Ti + C) + 20% Cu powder mixture is higher than that of the Ti + C mixture, despite the lower combustion temperature. The use of the “gasless” combustion theory to determine the kinetic parameters of the process from the burning rate of the powder mixture leads to a negative value of the apparent activation energy, which shows the inapplicability of the traditional approach. The results are explained within the framework of the convective-conductive model of combustion by the retarding effect of impurity gases released during heating of component particles ahead of the combustion front. Using the values of the burning rate of granular mixtures with granules 0.6÷1.7 mm, the burning rate of the substance of the granules is calculated, i.e. the burning rate of the powder mixture, in which the influence of impurity gases is leveled. The ratio of the burning rates of a substance inside granules and powder samples determines the measure of the influence of impurity gas evolution on the burning rate of a powder mixture.

The effect of mechanical activation of components and external pressure on the combustion of a heterogeneous Ti + C mixture under SHS compaction conditions has been studied. It is shown that when burning under pressure (15 MPa), a low-speed layered regime (4÷7 cm/s) is realized, without external pressure - non-stationary high-speed combustion modes (50÷70 cm/s): surface-annular and volumetric, carried out due to convective heat and mass transfer. A mechanism for high-speed convective combustion is proposed, based on the ignition of a heterogeneous mixture by a hot impurity gas released in the combustion wave and filtering through layered cracks and other macrodefects in the volume of charge compacts that were formed during the pressing of powder mixtures. Mechanical activation of the components of the reaction mixture reduces the density and strength of the compacts and increases the efficiency of the formation of macrodefects. External pressure has the opposite effect, as it prevents the formation of cracks and the propagation of hot impurity gas through them. Consolidated samples of titanium carbide up to a relative density of 95% were obtained in the bulk combustion mode.

This paper presents a study of the dependence of the acoustic emission parameters recorded during quasi-static compression and the shock-wave sensitivity characteristics of parts made of plastic-bonded HMX on the filler particle size. The dependence of the acoustic emission parameters on the HMX particle size was used to describe the possible variants of degradation of the explosive structure under shock-wave loading, which are considered as the cause of the difference in shock wave sensitivity.

To develop a green primary explosive, we prepare an Al@KIO₄ nano-thermite using spray co-precipitation and then mix it with pentaerythritol tetranitrate (PETN) to form a PETN/Al@KIO₄ composite as a primary explosive. The thermite structure is characterized using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy, which indicates that the thermite is about 200 nm and well distributed. The combustion performance is investigated using high-speed photography and confined combustion experiments. The results show that the detonation time of PETN/Al@KIO₄ composites is 60 μs earlier than that of pure PETN, indicating that the thermite accelerates the process of the deflagration-to-detonation transition of PETN. The detonation performance of the composites is investigated, and it is verified that PETN/Al@KIO₄ can initiate RDX successfully and be used as a primary explosive. Moreover, the safety performance and long-term storage performance of the composite are evaluated, which shows that the PETN/Al@KIO₄ composite performance is steady and the initiation effect does not change after 20 years of storage.

In this paper, the behind-plate overpressure caused by a polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive fragment is theoretically and experimentally analyzed. The theoretical energy of the PTFE/Al/W reactive materials is calculated by analyzing the chemical reaction of these compositions. Furthermore, based on the one-dimensional shock wave theory and the energy release behavior of the reactive fragment, an analytical model of the behind-plate overpressure is developed. By using binary quadratic polynomial fitting, a polynomial expression of the mass loss of the initiated reactive materials is derived based on the experimental data. The results show that the theoretical analysis model can be used for the estimating the overpressure when a reactive fragment impacts an aluminum plate within experimental conditions.

In the development of specialized explosion-proof chambers subject to increased requirements for strength reliability, an important issue is the choice of the material of the power block subjected to pulsed (dynamic and shock-wave) loads. As a rule, such structures are manufactured from industrial pipes of low alloy steel of various standard sizes. This always involves the question of choosing the steel grade, especially at the stage of computational justification of their explosion resistance, since the dynamic strength characteristics of the pipe material is generally unknown. This paper presents for the first time the results of a study of the static, dynamic, and shock-wave compressive and tensile strengths of 17G1S, 09G2S, and 10G2FBYu pipe steel of K60 strength class. In addition, comparative data on the explosion resistance at strain rates of (2÷5) ·10² c^-1 of pipes from 09G2S and 10G2FBYu steels.

The Priobskoe plateau is characterized by a high diversity of plant communities. It is associated with the specific features of the relief, hydrology and edaphic factors. Currently, a lot of separate works on the syntaxonomy of vegetation have been published for certain areas of the Priobskoe Plateau, but there is't unified checklist of communities. Its compilation will allow assessing the phytocoenotic diversity of the region and identifying “blind spots” in the study of the territory. A database of 1530 published geobotanical descriptions was created in the IBIS 7.2 program in order to analyze the syntaxonomic coverage of the vegetation in the Priobskoe plateau. Based on those, the prodromus of vegetation was compiled, which included 17 classes, 29 orders, 44 alliances and 103 associations. It covers the frequency of associations in the right-bank and left-bank parts of the plateau - separately for the steppe and forest-steppe zones (table). For each association, the position on the soil moisture and richness-salinization gradients was determined using phytoindication scales. This resulted in the creation of the ordination schemes of associations (Fig. 2). The vegetation of the forest-steppe zone on the left bank of the Ob is represented by 63 associations, 35 alliances, 24 orders and 16 classes. Steppes, meadows, forests, halophytic, aquatic and semi-aquatic communities are widespread here. The diversity of aquatic and semi-aquatic vegetation is associated with the large number of rivers and lakes. Forest coenoses are formed along the ravine and hollow systems and suffusion depressions. Natural meadows are found in small areas in the edges and clearings of small-leaved forests, ribbon forests, along the fields and idle lands. The tops and slopes of the ravine and hollow systems feature well-preserved steppes. The steppe zone vegetation of the Priobskoe plateau left bank is less diverse. It is represented by 22 associations, 13 alliances, 10 orders and 8 classes. Moisture deficiency results in the dominance of steppe communities and is the reason for the small number of associations representing meadows and forests. To date, complete information on the diversity of the forest, halophytic, aquatic and semi-aquatic vegetation in this area is not available. The right-bank part of the Priobskoe plateau is represented by 50 associations, 23 alliances, 14 orders and 6 classes. The vegetation of this territory is close to the left-bank forest-steppe. The main difference is the absence of halophytic communities. This is related to the good drainage of landscapes, which prevents the development of saline soils. Our studies have revealed the diversity of the Priobskoe plateau vegetation. The three areas of the plateau differ from each other markedly in terms of syntaxonomic diversity. This is associated with the differences in natural conditions and the degree of coverage.

We studied the seed set of the andromonoecious Oenanthe aquatica (Fine-leaved Water-Dropwort), a biennial or perennial mono- or oligocarpic herbaceous plant. Our survey was carried out in natural conditions of the Moscow region in 2021 according to generally accepted methods of studying plant seed sets. We showed that the seed set of individuals depends on the degree of synflorescences branching. Fine-leaved Water-Dropwort has two types of individuals with umbels on shoots of I-III and I-IV orders. O. aquatica has a high potential (number of ovules per individuals) and real (number of seeds per individuals) seed set (up to 21 490 seeds per individual) and the proportion of perfect flowers forming full seeds (95.8-96.8 % per individual). The potential and real seed set of terminal umbels is lower than that of individual umbels on shoots of the second orders. In Fine-leaved Water-Dropwort, the seed set of umbels on shoots of the same branching order naturally increases with an increase in the branching of the shoot system. The contribution of the seed set of umbels to the total seed set of O. aquatica individuals also depends on the degree of synflorescences branching. With an increase in the branching of the shoot system, the share of seed set of terminal umbels and umbels on second-order shoots gradually decreases. These characteristics of umbels on third-order shoots naturally increase due to both their numerical predominance.