Abstract The notable interest in the practical use of the process of oxidation of dispersed aluminum by water as a source of hydrogen gas for the needs of hydrogen energy requires not only an understanding of the mechanism of the process but also the capability of its mathematical modeling. In the present work, such a modeling was performed based on the results of an experimental study of the kinetics

Abstract The effect of the frequency and amplitude of mechanical action on the stability of the modes of the liquid-phase bimolecular reaction of the formation of urethanes from alcohol and isocyanate at the initial equilibrium of the type of stable focus is studied by the method of mathematical modeling. At the given amplitude of exposure, two critical frequency values are observed. At a relatively

Abstract The structure of hydrated ions of dichloroacetic acid (DCA) is established by electrospraying aqueous solutions of DCA into the vacuum chamber of a mass spectrograph. At an acid concentration of 0.01 mol/L, the number of hydrated ions decreases monotonically with an increase in the degree of their hydration. The resulting mass spectrum provides information on the distribution of hydrated ions

Abstract Phenylacetylene and its chemically active isomer pentalene play an important role in the formation and destruction of polyaromatic hydrocarbons—the main components of the soot microparticles formed during the combustion of fossil fuel, which are the most dangerous anthropogenic aerosol air pollutants for human health. The probable mechanisms of the decay of phenylacetylene and its isomers

Abstract Fast changes in the kinetic characteristics occur at the beginning of the transition processes of nonlinear chemical reactions, which are often not observed during nonstationary experiments. These periods of fast relaxations may carry important information about the mechanisms of complex reactions. The evolution of the period of fast relaxations of typical chemical reactions as they move away

Abstract Ultrasonic oscillations of spall plates with a frequency of several MHz occur in the form of a standing wave. The reverberation of the plate is related to the ultrasound category with sufficiently large amplitudes of the vibrations. The periodic change of the compression–tension cycles, characteristic for oscillation processes, leads to the localization of the plastic deformation at the nodes

Abstract In this paper, we study the energetic capabilities of four N-dinitro- and N-trinitromethyl derivatives of nitroazoles described in the literature as potential components of composite solid propellants. Using the thermodynamic calculations, some of the considered compounds are shown to have good potential for the creation of solid propellants with improved energy characteristics based on them

Abstract The paper presents the structural organization of the surface (selective) layer. The amorphous phase of the cellulose acetate composite membrane is formed at a certain stage of the technological cycle of producing the cellulose acetate membrane. It presents a mass of broken, entangled, and twisted macromolecular chains connected by a network of hydrogen bonds of various strengths. Analysis

Abstract The adsorption of hydrogen on bimetallic gold–nickel and gold–copper nanoparticles is simulated quantum chemically. We find that the changes in the adsorption properties of the bimetallic nanosystem are due to the change in distances between atoms and the redistribution of the electron density in the cluster. This leads to an increase in the bond energy of the hydrogen atom near the Ni/Cu

Abstract In this study, the dependences of the velocities and maximum combustion temperatures on the initial temperature for initial and mechanically activated Ti + Ni mixtures are determined. For activated mixtures, the transition temperatures from the layer-by-layer combustion to the thermal explosion mode are established. The maximum heating temperatures during a thermal explosion are determined

Abstract The paper experimentally demonstrates the possibility of synthesizing cast W–C–Ni composite materials (CMs) by SHS metallurgy from highly exothermic mixtures based on WO3 and NiO oxides and a complex reducing agent consisting of Al, Ca, and graphite at an elevated gas (nitrogen) pressure. It is shown that by varying the WO3 and NiO ratio, the initial mixtures of the contents of carbon, aluminum

Abstract The results of investigating the heat from the explosion of individual and aluminized blasting compounds shows that, when testing an unconfined charges, the explosion’s products undergo intense secondary heating when they reach the wall of the calorimetric bomb’s inner cavity. Due to the secondary heating in the products, the chemical reactions are resumed, and the final composition of the

Abstract In the past few years, new systems have been sought to increase the efficiency of aviation fuels through the introduction—together with ordinary hydrocarbons—of high-enthalpy hydrocarbons, such as aromatic acetylenes, and a small amount of solid oxidizer for the preliminary dispersal of the fuel before it enters the afterburner. A new phenomenon has been discovered: the temperature of the

Abstract The reaction of radical of iodine oxide (IO) with hydrogen sulfide in the temperature range of 273 to 368 K is studied by the method of resonance fluorescence of iodine atoms. The temperature dependence of the rate constant of this reaction is described by the expression kII(T) = (1.6 ± 0.3) × 10–14exp(1035/T) cm3 molecule–1 s–1. It is proved that these substances react mainly on the wall

Abstract The example of the lowest 1S resonance of the H– anion demonstrates that the resonance energy and its width calculated by way of finding the optimal point using the method of the complex absorbing potential has a systematic error, whose magnitude depends on the parameters of the absorbing potential and on the approximation used to solve the Schrödinger equation. It is shown that the accuracy

Abstract It is shown that nanosized wires with a length of up to ~1 cm or longer from metal nanospheres observed in liquid helium can be efficiently self-assembled in liquid nitrogen, which is a much cheaper and more technologically sophisticated method than the other available methods. The negative effect of the higher temperature can be compensated by applying a uniform electric field with the intensity

Abstract Colloidal particles of iron hydroxide produced by the hydrolysis of an iron(III) chloride solution in hot water catalyze the consumption of hydrogen peroxide and initiate the oxidative decomposition of impurities present in technical cellulose. This causes the bleaching of cellulose, and its degree depends on the concentrations of reagents and conditions of the process. The main products of

Abstract This study is aimed at statistically analyzing the ionospheric response to geomagnetic storms based on the data from the global ionospheric maps (GIMs). The global electron content and average zonal values of the total electron content for five latitudinal zones (equatorial zone, mid-latitude zones of the Northern and Southern Hemispheres, and high-latitude zones of the Northern and Southern

Abstract Satellite experiments at low latitudes have shown that energetic (tens of keV) electrons and protons can penetrate from the Earth’s radiation belt near the equator into the ionosphere. The effect of the fluxes of these particles on the upper atmosphere and ionosphere remains understudied. In this study, local variations in the concentration of ionospheric ions in the regions of injection of

Abstract Since 1964, the Kaliningrad branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences (IZMIRAN) has been conducting regular observations of the parameters of the lower atmosphere, ionosphere, and variations in the Earth’s magnetic field. The base of the measuring equipment, located in Ulyanovka village, Kaliningrad region (54°

Abstract The article assesses the impact of the main significant external factors in determining the TNT equivalency of air explosions. The effects of errors in measuring the distance to the epicenter and pressure on the front of the air shock wave (ASW) on the TNT equivalency value calculated by the Sadowski empirical is considered. The errors in determining the TNT equivalency arising from the wind

Abstract The phenomenon of thermophoresis in a gas discharge in neon is studied in the presence of structures of charged dust particles. This system can simulate gas with combustion products in the form of a condensed dispersed phase. The relationship of the thermophoresis force acting on charged dust particles in a plasma with their concentration and gas pressure is analyzed. It is shown that with

Abstract The structure of the flow and temperature field behind a reflected shock wave in a shock tube is studied by numerical modeling. Two possible scenarios of the formation of the regions of elevated temperature, which are the potential ignition kernels of the gaseous mixture under the study, are demonstrated. Both scenarios are assessed as equally probable; however, depending on the parameters

Abstract The mechanisms of film formation during pulsed laser ablation of a MoS2 target were studied. The conditions for the deposition of laser erosion plume were determined. This made it possible to obtain coatings with a porous structure consisting of round Mo nanoparticles coated with a thin shell of amorphous molybdenum sulfide MoSx > 2. Due to its hybrid structure, the MoSx > 2/Mo nanomaterial

Abstract The antiradical properties and biological activity of natural polyphenol—resveratrol—are studied. The chemiluminescence method recorded high values of the antiradical activity of this drug. Using the model system, it is shown that the drug in the concentration range of 10–5 to 10–12 M prevented the activation of lipid peroxidation (LPO) in the mitochondrial membranes of pea seedlings, which

Abstract The article considers several solid ethinyl derivatives (actually existing diethinylbenzene and a number of compounds not yet synthesized) as potential dispersants of fuels for direct-flow rocket engines. The density and enthalpy of the formation of the considered hypothetical ethinyl derivatives are estimated. Some of important parameters are studied characterizing their effectiveness as

Abstract The processes of lithization/delithization in a flat slit-like pore formed from defective silicene sheets and located on a copper substrate are considered in a molecular dynamic (MD) simulation. Depending on the type of the defects (mono-, bi-, tri-, hexavacancies), such a pore can hold up to 67, 86, 60, and 23 lithium atoms during the entire MD calculation with the duration of up to 1 ns

Abstract The thixotropic properties of aqueous solutions of the following polysaccharides are studied: chitosan, its water-soluble derivative the sodium salt of chitosan succinamide, and the sodium salt of carboxymethyl cellulose. These polymers have been selected due to their physiological activity and the possibility of using them for biomedical purposes. Studying the effect of the polymer concentration

Abstract The paper presents the results of studies of coatings formed by gold, copper, nickel, and palladium nanoparticles in various combinations on the surface of highly oriented pyrolytic graphite. It was shown that the structure of the bimetallic coatings and the adsorption of hydrogen, oxygen, and carbon monoxide on them are affected by interactions between dissimilar nanoparticles.

Abstract— Ethylene-propylene-5-ethylidene-2-norbornene terpolymerization is studied in a liquid propylene medium using catalysts based on metallocenes (MCs) of C2- and C5-symmetry, differing in the nature of bridges and ligands and activated by MAO. It is shown that the investigated MCs of C2-symmetry do not ensure the synthesis of terpolymers combining a high molecular weight (MW) and good diene incorporation

Abstract Based on the stationary one-dimensional model, the combustion process for a methane–air mixture in a slot matrix is simulated from the metal plates. The region of stable combustion is found and the possibility of such combustion in a wide range of the change in the flow rate of the gas mixture is explained. It is found that an increased length of the plates leads to an expansion of the stable

Abstract The propagation features and critical conditions of low-velocity detonation (LVD) in the high-density charges of finely dispersed ammonium perchlorate (APC) mixtures with combustible and explosive additives are studied. The effect of the relative charge density, the combustible component type, and the ratio of mixture components, including the mixtures strongly enriched with a combustible

Abstract The results of an experimental study of shock wave (SW) attenuation in mixtures of magnesium and aluminum with solid metal oxides upon contact blasting of explosive charges are presented. Faster attenuation is found in reactive mixtures compared to homogeneous materials of similar compressibility and inert mixtures, which is related to the occurrence of fast reactions of components behind

Abstract The mechanism of the interaction of six sulfur-nitrosyl iron complexes capable of releasing nitric oxide as a result of the spontaneous hydrolytic decomposition with a erythrocyte suspension is studied. A kinetic model of the process, which includes reactions of the NO released from the complex into the solution, the NO interaction with oxyhemoglobin within the erythrocyte and dissolved oxygen

Abstract An experimental study of the features of the critical transition between two kinetic combustion regimes of gas-air mixtures reacting by a chain mechanism is carried out. The presence of two radically different combustion modes is experimentally confirmed by the example of the combustion of propane–air mixtures, both containing an inhibitor (trifluoromethane) and without it, and in complete

Abstract The model composition of municipal solid waste (MSW) and its ash chemical composition are characterized. Mineral compounds and melting points are studied using a variety of analytical methods, including XRD, FTIR, and AFT. The main parameters of slag formation are calculated: base-to-acid ratio, slag viscosity index, and fouling coefficient. Solid municipal waste ash contains significant amounts

Abstract An analysis of the results of a three-dimensional numerical simulation of the flow in a conical shock tube (CST) with an angle of 38° revealed that the blast waves formed in such a tube have a pressure profile similar to spherical shock waves (SSWs) with a pronounced rarefaction phase following the compression phase. It is established that the main difference between the flow in conical geometry

Abstract In this paper, we study the effect of a heterogeneous autocatalytic reaction on the quartz reactor surface occurring after ignition in an H2/O2 medium near the third limit on the initiation of an explosion of a hydrogen–oxygen mixture in a cold volume of lines adjacent to the reactor. Under certain conditions, a second flash occurs in most experiments in a cold volume. The probable chemical

Abstract The gasification of used tires in the filtration combustion mode is studied using calcium-containing additives, both chemically inert and those capable of absorbing sulfur. It is found that during the gasification of compositions with an inert additive, 28, 29, and 43% of the sulfur contained in the initial material passes into the ash, resin and gaseous products, respectively. The introduction

Abstract The paper considers the relativistic Renner effect 4Π × π, which occurs in linear triatomic molecules containing heavy atoms. The vibronic matrix is calculated in the three-electron model. The electronic Hamiltonian is expanded in a Taylor series in π-modes taking into account the terms of the main, first, and second orders. To calculate nonzero elements in the vibronic matrix, group selection

Numerical simulations are performed of reaction kinetics in the gaseous products of pyrolysis of polypropylene and waste tires at atmospheric pressure in the temperature range of 800 to 1300 K. The initial conditions are set by using the experimental data available in the literature. The reactions between gaseous pyrolysis products are found to result in a decrease in the mixture’s temperature of polypropylene

In this paper, we perform a numerical analysis of the parameters of shock waves (SWs) generated during the expansion of cylindrical volumes of compressed methane. A single dimensionless approximation of the overpressure dependence on the distance is obtained using precise numerical solutions. The overpressure values ​​in the SW are estimated for both the near and far zones. Comparison with previously

This work presents the review and classification of the scenarios of the development of the final stage of flame acceleration in channels and tubes including the transition to detonation on the flame front and formation of the conditions for kernel ignition ahead of the front. An approach to the numerical assessment of the detonability of combustible gaseous mixtures is formulated based on the classification

The use of boron-based powder materials in solid propellant compositions is an effective method for increasing the energy characteristics in the combustion chamber due to increasing the released energy through the combustion of boron particles. In this study, powders of amorphous boron and aluminum borides, obtained by the method of self-propagating high-temperature synthesis—the SHS method, which

Abstract—The spectral luminescent and electrophysical properties of polymer films based on poly-N-vinylpyrrolidone with the stabilized derivatives of tetraphenylporphyrin in various aggregation states (monomers, J- and H-aggregates) were investigated. Films containing a monomolecular form of porphyrins are characterized by intensive fluorescence. For films with J-aggregates an electric response that

AbstractAlthough the polymer electrolyte membranes provide a comprehensive solution to fuel cell technology, it provides several complemented problems such as fuel crossovers, CO poisoning, low durability, and high cost. Recent scientific developments have focused on biopolymer membranes based on chitosan and alginates, which are addressed to meet these problems. This comprehensive review is a perspective

AbstractA global analysis of the fluorescence decay kinetics of a chloroform extract of lipofuscin granules from the retinal pigment epithelium cells of human cadaver eyes is performed. The analysis makes it possible to reconstruct the individual fluorescence properties of four groups of fluorophores belonging to bisretinoids and the products of their photooxidation and photodegradation. The characteristic

Abstract—The plasma coagulation factor XIII (рFXIII) is a key protein of the blood coagulation systems, the main function of which consists of the enzymatic covalent stabilization of the polymeric structure of fibrin. The protein has a heterotetrameric structure consisting of two catalytic (FXIII-A2) and two regulatory (FXIII-В2) subunits. Using a high resolution mass spectrometry, hypochlorite-induced

Abstract—New composites based on keratin and EVA (the copolymer of ethylene and vinyl acetate) are developed. Their mechanical and rheological properties and their process of biodegradation are investigated. These materials’ characteristics were with composites based on polyethylene and keratin to study interfacial interactions. Differences in their mechanical properties are revealed. It is shown that

AbstractStudies on polymer composites based on polyolefins (polyethylene; polypropylene; their mixtures; propylene–ethylene, ethylene–vinyl acetate, and ethylene–octane copolymers) and various natural compounds were reviewed. The reviewed studies analyzed the influence of various factors on the formation of the biodegradable properties of polyolefins.

Abstract—An increase in the rate of catalytic CO oxidation for platinum nanocoatings was measured when the electrical stress of various polarity and value was applied to a coating from an external source. Under conditions of the experiment at 250°C, atmospheric pressure and the starting composition mixture of 4.8% CO + 10.2% O2 + Ar, applying the positive stress of +10 or +30 V on a coating leads to

Abstract—The sorption of copper and lead ions by polymeric sorbents based on crosslinked polyacrylamide containing chemically bound or immobilized 15-crown-5 and 18-crown-6 was studied, as was the effect of various parameters on the efficiency of metal sorption from aqueous solutions. It is shown that the sorption capacity of these sorbents increases dramatically with an increase in the content of

AbstractThe autocatalytic formation of a chromophore in a green fluorescent protein, which is actively used as a marker for visualizing processes in living systems, is an important example of multistage reactions in protein macromolecules. The kinetic, spectral, and X-ray structural experimental studies and supercomputer calculations by molecular modeling methods are devoted to the study of intermediates

Abstract—The interaction energies of fragments of aluminoborophosphate chains with water molecules and nitrogen-containing compounds are calculated using a density functional theory (DFT). The conformational changes of monomer units of aluminophosphate and molecular complexes during the formation of hydrogen bonds are analyzed. The complexation of aluminoborophosphate with various nitrogen-containing

AbstractThe wave function and ground state energy for a discrete nonlinear Schrödinger equation (DNLSE) with a trap can be found numerically using an iterative process. However, this approach does not always give convergent results. A functional is proposed that is not an energy functional, the minimum of which always gives the ground state of the system under consideration.

AbstractThe results of kinetic studies of the recombination of radicals in the cage and in bulk of polymers obtained by nanosecond laser photolysis are summarized. The films of rubbers (poly(ethylene-co-butylene)), biaxially oriented polypropylene depending on the preliminary heat treatment, polystyrene, craton (polystyrene-block-poly(ethylene-butylene)-block-polystyrene), silicones, and acrylates

AbstractThe creation of new highly productive forms of potato by genetic engineering methods raises the question about the quality of transgenic tubers, which first of all relates to the properties of important storage compound such as starch. The article presents the results of studies aiming to the analysis of morphology, structure, and thermodynamic parameters of starch extracted from the potato

AbstractIn blasting in dense urban areas and piece stone mining, the issue of organizing gentle destruction modes arises, which requires the use of pyrotechnic compositions operating in the deflagration mode. In such compositions, ammonium perchlorate, ammonium nitrate, and other nitrates are used as oxidizing agents. Magnesium is often used as fuel. In this paper, the combustion of a three-component

AbstractIn this paper, we perform a comparative numerical analysis of turbulent combustion and harmful substance emission from a homogeneous combustion chamber operating on pure n-decane and mixed n-decane/hydrogen or n-decane/syngas fuels. The calculations were performed using the ANSYS Fluent program, and a reduced kinetic mechanism describing the oxidation of the fuels under consideration was developed

AbstractPolymer–polymer blends of ultrahigh-molecular-weight polyethylene (UHMWPE) and of low-molecular-weight high-density polyethylene (LMWPE) that contained 30, 50, and 80 wt % UHMWPE, were synthesized in a two-stage polymerization of ethylene over a rac-Me2Si(Ind)2ZrCl2/methylalumoxane catalyst. The conditions of the stage were chosen based on the results of study of one-stage polymerization of