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The lower temperature limits for flame propagation of mixtures of oil vapor with oxygen and nitrogen in the presence of liquid oil were determined. Experiments showed that the lower temperature limit differs significantly from that expected for oxygen. One reason for this discrepancy is that, in the presence of an ignition source and a large amount of oxygen in the gas phase, diffusion combustion of the liquid oil film present on the inner surfaces of the vessel can initiate. The flame propagates along this film to the bulk of the oil. As the oil continues to diffuse, a pressure increase significantly exceeds that expected for flame propagation through the gas phase.

The gas-dynamic, kinetic, and energy parameters of detonation in dual-fuel methane-hydrogen systems are presented: a) stoichiometric methane-oxygen and hydrogen-oxygen mixtures in various ratios; b) stoichiometric methane-oxygen mixture with added hydrogen in various ratios; c) stoichiometric hydrogen-oxygen mixture with added methane in various ratios; d) lean hydrogen-oxygen mixture with added methane in various ratios; e) enriched hydrogen-oxygen mixture with added methane in various ratios. The main behavioral patterns of such systems are discussed.

To improve inherent safety and reduce energy consumption in industrial explosives production, the water-soluble compound hexamethylenetetramine is being used to replace the traditionally used insoluble fuel oil in ammonium nitrate-based explosives. This oxidizer and fuel, combined in water, create an intermolecular explosive called an ammonium amine explosive. The effect of pH in the range of 4.0 to 5.8 on the density of this explosive, crosslinking time, microbubble formation, detonation velocity, and water resistance was determined. The studies were conducted using density measurements, a digital viscometer, an optical microscope, detonation velocity tests, and a conductivity meter. The results show that ammonium amine-based explosives prepared at various pH levels form numerous chemically sensitized microbubbles, the average diameter of which decreases as the pH decreases. Lower pH values are associated with higher foaming rates and shorter crosslinking and foaming times. The detonation velocity of ammonium amine-based explosives is 3,500-4,200 m/s, slightly lower than that of conventional emulsion explosives. Furthermore, a comparison of the water resistance of ammonium amine-based explosives with crosslinking times of 1 and 24 hours yields contrasting results. A pH of approximately 5.2 sets the boundary between in-situ mixed and packaged ammonium amine-based explosives. Packaged explosives show significant advantages at pH values above 5.2, while in-situ mixed explosives are more advantageous at lower pH values. These results provide a theoretical basis for improving the performance of this new water-resistant nitrated substance and simplify its industrial application.

Aluminum diboride (AlB₂) microcapsules coated with polyvinylidene difluoride (PVDF), fabricated by a simple rotary evaporation method, were studied. According to the morphology study, PVDF forms an intact outer shell on the surface of each individual AlB₂ particle. Compared with uncoated AlB₂, the AlB₂@PVDF microcapsule has a shorter ignition time, more intense combustion, and faster pressure build-up. At an appropriate PVDF content, the measured heat of combustion is higher than that of the composition with unencapsulated AlB₂, due to a higher heat release efficiency during combustion --- 92.3% (the efficiency of the composition with unencapsulated AlB₂ is 85.2%). Mechanistic study shows that the PVDF decomposition product likely accelerates the oxidation of AlB₂ at several reaction stages, providing higher reactivity of the AlB₂@PVDF microcapsules. The use of AlB₂@PVDF in explosives increases density, detonation velocity, and heat release with good component compatibility, while maintaining acceptable mechanical sensitivity. Therefore, AlB₂@PVDF microcapsules are a promising metallic fuel in composite energetic materials.

Using the molecular dynamics method, numerical experiments were conducted to study the dependence of the melting temperature of various materials (copper, silver, titanium, and silicon carbide) on the nanostructure size. Analysis of the obtained data showed that for all materials, starting from a certain nanostructure size, the melting temperature decreases with decreasing nanostructure size.

The problem of measuring particle size distribution in shock-induced flows is discussed. The design of a mobile holographic system developed by the authors, which implements the method of axial pulse holography, is presented. The system enables the acquisition of holograms with a field of view of approximately 20 mm in diameter and a depth of over 20 mm, and the recording of flows of lead particles ≥3-5 μm in size, moving at velocities up to approximately 2 km/s. Examples of shock-induced flows moving in a vacuum, recorded using the mobile holographic system, are presented. These flows consist of both individual particles 5-100 μm in size and, predominantly, filamentary formations 3-10 μm thick. Methods of analog and digital recording and reconstruction of holograms are discussed, as well as the problem of identifying particles in images reconstructed from recorded holograms.

A new type of ammonium nitrate-based explosive is presented, prepared by replacing diesel fuel with liquid coal fuel (coal atomized in water). Experimental results show that the higher the calorific value of the raw coal, the higher the detonation velocity of the new liquid explosive. For example, with a liquid coal fuel content of approximately 9-12% and a calorific value of 5,500 kcal/kg, the efficiency of the new explosive is relatively stable and achieves improved parameters: velocity equals 2,800-3,000 m/s, brisance increased by approximately 7-10%, and the work performed increased by approximately 8-24% compared to an explosive made from ammonium nitrate and diesel fuel. Minimal changes in the physical and chemical properties were observed during 30-day storage. At the same time, the blast efficiency of this explosive was significantly improved by adding composite additives consisting of a new coal-based fuel, diesel fuel, and an emulsifier. Blast tests under industrial production conditions were conducted at the Heidaigou open pit mine. The test results showed that the new explosive exhibits significantly improved brisance and greater work-producing capacity compared to ammonium nitrate- and diesel-based explosives.

Using the electric contact method, the influence of sample porosity, dispersion, and diameter on the detonation velocity of the individual low-sensitivity explosive triaminotrinitrobenzene (TATB) was studied. Data on the detonation wave front curvature were obtained. The results show that, under identical initiation conditions, the detonation process of TATB is complete after the detonation wave travels a distance equal to 3.5 times the explosive sample diameter and is independent of the porosity, dispersion, and diameter of the samples.

To study the effect of initial ambient pressure on the explosion parameters of thermobaric explosives (HE), static explosion experiments were conducted using trinitrotoluene (TNT) as a reference at both low and high initial ambient pressures. Various grades of thermobaric explosives were tested, and a correlation model was proposed for analyzing the overpressure and momentum of the blast shock wave in different initial environments, taking into account atmospheric pressure. Analysis of the pressure data showed that the general propagation and attenuation characteristics of blast shock waves from TNT and thermobaric explosives are essentially the same at different initial ambient pressures. As the initial ambient pressure decreases, both the shock wave overpressure and momentum decrease. The explosion propagation velocity also decreases with decreasing initial ambient pressure. Furthermore, as the explosive mass increases, the reduction in overpressure and momentum decreases for both thermobaric explosives and TNT, and the difference in the shock wave propagation velocities from these two types of explosives also decreases. A comparison of the correlation model results with experimental data yielded average maximum relative errors of 12.3% for TNT and 8.8% for thermobaric explosives in low-pressure environments relative to the shock wave overpressure. Momentum errors were 12% for TNT and 13.7% for thermobaric explosives. These results demonstrate the high accuracy of the correlation model. This correlation model allows one to determine the shock wave overpressure and momentum of an explosion at various initial ambient pressures, and to estimate the shock wave power generated by thermobaric explosives.

The question of how solid rocket propellants react to fragment impacts remains relevant. Identifying potential mechanisms for propellant propellant reaction to fragment damage is crucial for assessing the safety of solid rocket motors and developing high-energy, low-sensitivity propellants. In this study, a fragment impact experiment on a propellant propellant consisting of glycidyl azide polymer, hexogen, and triethylene glycol dinitrate (GRT) was conducted using a 14.5-mm ballistic gun and a high-speed camera to obtain images of the propellant reaction time history under various ballistic behaviors. Based on the obtained images and measured ballistic data, the relationship between propellant reaction characteristics, the primary reaction mechanisms, and two ballistic limits was analyzed. The results of a 10.0 mm diameter tungsten ball impact on a GRT charge contained in a 3 mm thick cylindrical steel shell show that the threshold reaction velocity corresponds to the ballistic limit of fragment penetration into the shell. Below this ballistic limit, no propellant reaction occurs. In the case of a significant reaction delay caused by the ignition of RDX crystal hot spots rather than ammonium perchlorate particles, the propellant reaction upon complete penetration is combustion. Only when a large number of ammonium perchlorate particles and RDX crystals simultaneously ignite hot spots, and the fragment's initial velocity exceeds the charge's ballistic limit by 2.2 times, can the charge undergo reactions more intense than combustion.