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Methods for the selection and analysis of condensed combustion products (CCPs) of large monolithic titanium particles with a diameter of 350 ÷ 460 μm in air at atmospheric pressure are described. Detailed data on the granulometric, morphological, and phase composition of CCPs and the number of particles produced by a single burning mother particle are presented. The following morphological types of CCP particles were identified: compact spheres (combustion residues of mother particles and their fragments) and airgel round and elongated comet-shaped objects (sparse fine particles consisting of chains of nanosized spherules). According to the ratio of O/Ti atoms, all types of CCP particles are oxide particles. The mass fraction of airgel objects in CCPs is 0.52 ÷ 0.98, and their physical density is about 0.8 g/cm³. The characteristic dimensions of compact spheres are 2 ÷ 410 μm, those of airgel round objects are 11 ÷ 470 μm, and the length of airgel comet-shaped objects can reach 13 mm. Typical sizes of spherules are 25 ÷ 100 nm. Large compact spheres 200 ÷ 400 μm in size typically have a gaseous bubble and a density of about 0.9 g/cm³.

Synthesis products in mechanically activated powder mixtures of titanium and nickel of three compositions corresponding to double intermetallic compounds have been studied. The mechanical activation of the mixtures was carried out in a planetary mill at an intensity of 40 g and a processing time of 20 min. The synthesis was carried out in the thermal explosion mode by heating mechanically activated mixtures in a sealed reactor in an argon atmosphere at an average heating rate of 70 ˚C/min. The phase composition of the powder products after synthesis and additional annealing was studied by X-ray diffraction analysis, and the results were discussed using literature data on the temperature dependences of the Gibbs energy of intermetallic compounds. It has been found that, regardless of the elemental composition of the mixtures, the intermetallic compound TiNi₃, which has the highest negative Gibbs energy, is predominantly formed during synthesis. Therefore, a single-phase target product was obtained only from a mixture of composition corresponding to TiNi₃. Thermal explosion products in mixtures of the other two compositions are multiphase. After annealing, the phase composition does not change qualitatively, and the quantitative changes in the phase content are insignificant.

The classical models of steady propagation of combustion and detonation waves in a combustible mixture describe the increase in the system entropy to a maximum value in the case of deflagration (subsonic) combustion of the mixture driven by slow processes of heat conduction and diffusion. In the detonation (supersonic) regime, however, where one of the leading roles belongs to the bow shock wave, the models predict that the combustible system after completion of the chemical reaction “chooses” the minimum increase in entropy. These predictions are inconsistent with the formulation of chemical thermodynamics that the entropy of the system reaches its maximum value after the spontaneous irreversible chemical reaction is finalized and the equilibrium state is established. It is shown in the present study that the predictions of the classical models on the minimum increase in entropy in the case of detonation are eliminated if detonation is considered as a process of combustion of a mixture preliminary subjected to an irreversible process of compression and heating of the initial mixture in the bow shock wave (chemical spike) with a corresponding increase in entropy of the initial mixture and subsequent energy release from the mixture in an irreversible process of mixture conversion to chemical reaction products.

On a pulsed gas detonation apparatus (PGDA) at initial atmospheric pressure, a study was made of the process of initiation and detonation in acetylene-oxygen mixtures C₂H₂ + k O₂, including those with a low content of oxygen near the upper concentration limit of detonation. The cell sizes, detonation velocities, and pressures in the detonation products were measured in the range k from zero to unity, and the composition of the detonation products was calculated. The upper limits of detonation in IGDA barrels with diameters of 14, 26, 46, and 104 mm and the volume of booster charges required to initiate detonation in the limiting modes are found. With regard to hydrogen energy, the technological chain methane ® acetylene ® hydrogen + nanosized detonation carbon is considered and an assessment is made of the characteristics of PGDA as a hydrogen generator.

The previously developed wide-range multiphase equation of state of Fe was used to calculate the shock pressure causing its evaporation during isentropic unloading up to 10^-4 GPa (1 atm). Calculations were made for three initial states of matter: pressure 1 atm and temperature 298 K (“cold” initial state), 1 GPa and 1 500K (“warm” state), and 40 GPa and 4 000 K (“hot” state). The shock pressure is 359, 261, and 132 GPa, respectively. These values are generally lower than the estimates of other authors. Arguments are given in their justification.

The aim of the article is to point out the dangers arising from the properties of plastic dust and what influence its properties have on the origin and course of the explosion. The present study deals with a sample of polyethylene dust, by-product of granulate production and storage. The explosion tests are performed on containers of a similar shape to those found in plants. The volumes of the closed vessels are 1.35 m³ (N1) and 5.45 m³ (N2). The tests are conducted in vessel N1 with a venting area DN 250 on the top of the vessel, in vessel N2 with a venting area DN 585 or DN 775 installed on the upper flanges of the vessels, and in vessels interconnected by pipes with a diameter DN 150 and length of 3, 6, and 10 m. The experiments show that the pressure of the explosion in technological equipment may reach higher values than those obtained in laboratory tests. During the explosion propagation in the connected vessels, the effect of overpressure appears due to precompression; as a result, the measured pressure and the rate of pressure rise are many times higher than the values measured only in the vessel itself with a venting area. As the explosion propagates from a larger volume vessel to a smaller volume vessel, the effect of precompression of the mixture increases the explosion parameters in the smaller vessel despite the opening areas of both vessels. Other elements can be also used to ensure sufficient explosion protection. The results also describe the effect of the length of the pipeline route by which the vessels are connected.

The explosive formability of common age-hardenable Al alloys (2024-T4, 2024-T6, 6061-T4, 6061-T6, 7075-T4, and 7075-T6) is investigated experimentally. Manufacturers utilize explosive forming to produce parts having large and complex geometries in a single operation. To investigate the explosive formability of the most common Al alloys used in the aerospace/aircraft industry, an experimental die design is constructed. Tensile tests are carried out to determine the mechanical behavior of the alloys at low strain rates. Charpy V-notch tests are used as input values to determine the fracture toughness and fracture energy. The strain rate considering the expansion angle is calculated through the analytical formula of the Gurney metal velocity. The strain rates obtained by explosive forming conducted in air are calculated roughly as 1.1·10⁵ s^-1, which is an extreme rate. The experimental results reveal that the 6061-T4 Al alloy could be explosively formed to the demanded geometry without any hollows, cracks, tearing, and fractured regions. It is clear that the T6 temper condition significantly improves the strength of the tested alloys, accompanied by reduction of ductility and crack initiation potential. Except for the 6061-T4 Al alloy, all of the tested alloys are fractured during explosive forming tests. Stereo microscopy and scanning electron microscopy investigations reveal transgranular fracture and cleavage facets resulting from brittle fracture initiated by high strain rates, which occurs in the peak-strength temper condition-T6 of the tested Al alloys.

In 1968-1985, in the course of study of phytobenthos in the Lake Baikal, L.A. Izhboldina sampled and analyzed material on the structure and distribution of meio- and microphytobenthos in Chivyrkuyskiy Gulf, the second-largest gulf in the lake. Until now, just a general description of phytobenthos structure was published. The article presents schemes of 18 profiles, 12 of which (more than three quarters of sampled data) were laid during July 1985. For each profile we have drawn a scheme where indicated dominant and codominant species, type of bottom substrate, generalized biomass of community (gr/m²) and the number of species for every station (sampling site). Due to the predominance of shallow depths and mechanically unstable sandy, silty-sandy and silty substrates, the structure of benthic vegetation is monotonous, and phytobenthos belts described for Lake Baikal, are not expressed. There is also a certain gradient in communities along the central part of the gulf from its top to the mouth. Small bays along the western shore of the gulf have certain specificity. In some parts of the gulf, Chaetomorpha curta (Chlorophyta), Cladophora aegagriopila, C. meyeri, C. meyeri var. gracilior (Chlorophyta), Collema ramenskii (Ascomycota), Gloeothrichia pisum (Cyanophyta), Nostoc pruniforme (Cyanophyta) are comparatively frequent and abundant. Noteworthy, the high occurrence of such algae as G. pisum and C. aegagropila, which are absent in littoral of the open Baikal. Charophyta (Chara sp., Nitella sp.) often form communities at depths of 5-8 m. Among vascular plants, the most active are Lemna trisulca and Potamogeton perfoliatus. The alien North American Elodea canadensis and the zignem algae Spirogyra sp., settled in the lake and experienced catastrophic outbreaks of development in subsequent years, in 1985 were represented by few samples.

Mires are valuable nature conservation complexes with unique biological diversity. The presented work contains the results of studying the floristic diversity of vascular plants in protected mires in the southern part of the Sverdlovsk Region (Russia). The studies were carried out on four peat lowland plain mires: Maloe Lake, Berezovoe, Chernoe (Kamensky District) and Bagaryak (Sysertsky District). Until now, information about the floristic richness of the mires of the southern part of the Sverdlovsk Region has remained fragmentary, and therefore the study allows us to fill in the existing “gaps”. In addition, the studied mires are the southernmost mires of the Sverdlovsk Region within the Trans-Urals, which emphasizes their high environmental significance. The research was conducted in 2021. The territory of each mires was surveyed by the traditional route-reconnaissance method, taking into account the intra-mire hydrographic network. The article provides a list of discovered species of vascular plants. Author’s materials are supplemented with information from the collection of the Museum of the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences (SVER). In total, 188 species of vascular plants belonging to 123 genera, 54 families and 4 divisions were identified in the flora of the studied mires. The leading families in terms of the number of species are Cyperaceae, Asteraceae, Poaceae, Rosaceae, Orchidaceae and Salicaceae. The leading genera are Carex, Salix, Cirsium and Galium. The flora is dominated by plurizonal and boreal species with a wide distribution (Holarctic, European-West Asian and Eurasian). Among the biomorphological groups, polycarpic herbs are of significant importance (145 species, 78 %) of which 45 % are rhizomatous plants. Among the species we have discovered Malus baccata and Carduus acanthoides which are alien and appeared due to ornitho- and anemochory. In the studied mires, cenopopulations of 14 rare species listed in the Red Data Book of the Russian Federation and the Red Data Book of the Sverdlovsk Region were recorded. The work highlights the importance of maintaining mires in a natural state to maintain overall phytodiversity and the possibility of preserving rare and vulnerable plant species.

Genus Epimedium is the largest genus of herbaceous plants in the Berberidaceae family. It includes about 50-65 species. Species of the genus Epimedium have a traditional use in Chinese, Korean and Japanese medicine. They are also known as ornamental plants. Three plant species of Epimedium grow in Russia: E. colchicum (Boiss.) Trautv., E. koreanum Nakai and E. macrosepalum Stearn. All of them are included in the Red Data Book of the Russian Federation. The purpose of the study is a comparative morphological and anatomical study of rhizomes and roots of E. colchicum and E. macrosepalum belonging, respectively, to the subgenera Rhizophyllum and Epimedium. Materials for the study have been collected in the botanical garden of All-Russian Scientific Research Institute of Medicinal and Aromatic Plants. We used an MBS-10 binocular and an Axioplan 2 imaging Carl Zeiss microscope. Cross sections of rhizomes were stained 1) with an alcoholic solution of phloroglucinol and concentrated HCl; 2) 0.1 % cresyl violet solution. Cylindrical rhizomes, non-yearly branching, characterize both species. Rhizomes are dark brown with numerous thin adventitious roots. Rhizomes of E. colchicum are short and thick (diameter 7.8 ± 0.1 mm, length of annual growth 42.9 ± 2.3 mm); rhizomes of E. macrosepalum are thin and elongated (rhizome diameter 2.5 ± 0.1 mm, length of annual growth 65.5 ± 4.8 mm). The zones of the primary bark and the central cylinder on transverse sections of rhizomes are distinguished. Open conducting bundles are located in one circle. The pith is lignified. Idioblasts with druzes of CaC₂O₄ crystals are in the inner zone of the parenchyma of the primary cortex of E. macrosepalum. E. colchicum has relatively wide pith rays (up to 20 rows of cells), the presence of groups of lignified protophloem fibers, and the absence of sheaths of lignified fibers. E. macrosepalum is distinguished by relatively narrow (2-10 rows of cells) pith radiuses, the absence of bundles of lignified protophloem fibers, and the presence of sheaths of lignified fibers.