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In this work we analyzed the thermogravimetric data on the fiber phase change composites loaded with eicosane or stearic acid. The consistency of the thermogravimetric data can be checked using the Kolmogorov–Johnson–Mehl–Avrami equation with a temperature-dependent rate constant. However, the first derivative analysis shows that the employed equation should be further modified in order to account for the asymmetry of the peaks on the first derivative of thermogravimetric curves. [ABSTRACT FROM AUTHOR]

The adsorption of organic phase-change materials (PCMs) on the supporting fibers has been demonstrated as a versatile and efficient method for developing stable composites with thermoregulatory properties. These composites are promising as energy saving additives in dry building mixtures. However, developing composite fibers with an optimal morphology to maximize their content and thermoregulation in the desired material is still a significant challenge. In this study, we have created stable composite fibers by depositing the organic PCM eicosane on fungal mycelial biopolymer fibers. The resulting composite has a fibrous structure with a lateral size of 1.5–2 μm and a latent heat capacity of 70 J/g. It was mixed with dry gypsum powder at a weight ratio of 30%. Electron microscopy analysis showed a uniform distribution of fibers throughout the hardened gypsum layer. The DSC analysis revealed that the inclusion of the composite to the plaster significantly improved its thermal properties, allowing for the storage and release of latent heat with heat capacity of 30 J/g. Temperature measurements within the hardened plaster showed that the presence of thermoregulating fibers slowed down the heating process between 32–38°C and cooling between 38–35°C, corresponding to the melting and solidification of eicosane in the composite structure. Finally, model experiments with a testing chamber demonstrated that the accumulation and release of the thermal energy resulted in the decrease in internal air temperature during the heating cycle and in the increase of internal air temperature during the cooling cycle, respectively. [ABSTRACT FROM AUTHOR]

In November 2020, the IceCube Neutrino Observatory registered a neutrino event with an energy of 150 TeV directed at the Cygnus Cocoon gamma-ray source. In the Carpet-2 experiment, as part of the Baksan Neutrino Observatory (BNO), a sharp increase in the flow of events with an energy above 300 TeV was recorded from the same direction within the angular accuracy of the events. This flux is 4 orders of magnitude higher than the expected intensity of gamma quanta of this energy region according to data in the region of less than 100 TeV. It was expected that such a powerful flare could be registered by the TAIGA-HiSCORE installation of the TAIGA astrophysical complex. We analyzed the events of the EAS recorded by the installation of TAIGA-HiSCORE for 18 h in October–November 2020 from the Cygnus Cocoon source. This article provides the upper limit of the expected excess flow. [ABSTRACT FROM AUTHOR]

The paper is devoted to the modeling and analysis of data detected by the TAIGA-IACT installation in the stereo mode. Five Imaging Atmospheric Cherenkov Telescopes (IACT) with a viewing angle of 9.6° are expected to be included in the installation. Today there are three telescopes spaced far apart (from 320 to 500 m) in the installation. The effective area of the installation is as large as 0.6 km2; therefore, it is possible to conduct statistically significant measurements of weak γ-ray sources in the energy range above 10 TeV over a reasonable observation time (300–400 h). The Monte Carlo procedure for simulating the hadrons and γ-rays detected by the telescopes is described as is the procedure for reconstructing the parameters of extensive air showers, such as the arrival direction of an event, the axis position, the depth of the maximum of shower development (Xmax), and the primary-particle energy. In order to solve the problem of γ-hadron separation, the criteria for selecting γ-rays detected in the stereo mode have been optimized and the effective area of the installation has been calculated. [ABSTRACT FROM AUTHOR]

The status of the TAIGA experiment (Tunka Advanced Instrument for cosmic-ray physics and Gamma-ray Astronomy) located in the Tunka Valley is presented. The paper presents mainly the tasks, developed approaches for their solution, and first results on high-energy gamma-ray astronomy (10 TeV and higher) obtained from a two- to three-year exposure. The current tasks of gamma-ray astronomy and plans for development of the installation are discussed. [ABSTRACT FROM AUTHOR]

The deposition of organic phase-change materials (PCMs) on the supporting fibers was shown as a simple and effective way to prepare stable composites with thermoregulating properties, which are feasible as functional additives to dry building mixes. However, the preparation of the composite fibers with optimal morphology to improve their content and thermoregulating performance in the target material still remains challenging. Herein, we report on the stable composite fibers prepared by the deposition of organic PCM eicosane on the biopolymeric fibers of fungal mycelium. The prepared composite had a fibrous morphology with the longitudinal diameter of 1–1.5 μm and the latent heat capacity of 63.2 J/g. The composite was mixed with the dry powder of gypsum plaster with the mass content of 15% and 30%. The electron microscopy revealed a homogeneous distribution of the fibers within the hardened plaster layer. The differential scanning calorimetry confirmed that the addition of the composite to the plaster enhances its thermal performance and brings latent heat storage and release capability with latent heat capacity of 8.2 J/g and 18.2 J/g depending on the composite content. The measurement of the temperature in the volume of the hardened plaster demonstrated that the addition of the thermoregulating fibers effectively reduce the heating rate in the range of 37–39°C and the cooling rate in the range of 38–34°C, corresponding to melting and crystallization of eicosane in the composite structure. [ABSTRACT FROM AUTHOR]

The article reports on the current status of the Baksan Large Neutrino Telescope project and describes some selective results of the first stage of the project, a detector prototype with a liquid scintillator mass of 0.5 tons. The results of the second stage of the project, a prototype with liquid scintillator mass of 5 tons, and project prospects also presented. [ABSTRACT FROM AUTHOR]

We present the status of research and development of a new highly efficient liquid scintillator based on linear alkylbenzene and organosilicon scintillation fluor, so called NOL (Nanostructured Organosilicon Luminophore). The measurements of the emission kinetics under irradiation by gamma-quanta and alpha-particles were performed. The results of long term stability measurements are decribed. [ABSTRACT FROM AUTHOR]

The current state of the Baksan Large Neutrino Telescope project is reviewed. Selected results are presented from the first stage of the project, a prototype detector with a liquid scintillator weighing 0.5 tons. Results from the second stage of the project, a prototype with a liquid scintillator having a mass of five tons, are described along with prospects for the project. [ABSTRACT FROM AUTHOR]

An analysis is performed of the spectrum of gamma rays from the Crab Nebula in the 4–100 TeV range of energies, obtained using data from two Atmospheric Cherenkov Telescopes that are part of the TAIGA complex. A way of selecting and restoring the energy of gamma rays is described that includes a procedure for restoring the energy spectrum. [ABSTRACT FROM AUTHOR]

The Tunka-Grande scintillation array is described. Scientific results obtained over the first five years of its operation are presented. Prospects for studying cosmic rays in the 1016–1018 eV range of energies are discussed. [ABSTRACT FROM AUTHOR]

The possibility of using composite fibers with phase change properties as a thermoregulating additive to dry building mixes (mortar mix) with the possibility of accumulating thermal energy under the action of sunlight and a high-frequency alternating magnetic field is studied. Composite fibers were obtained by adsorption of the organic phase-change material eicosane on fibers of microfibrillar cellulose modified with magnetite nanoparticles. The obtained composites demonstrated specific values of stored thermal energy in the range of 129-148 J/g, depending on the content of eicosane in their composition. It is shown that the addition of 10–15% wt. of composite fibers to the dry building mix makes it possible to store and release thermal energy in hardened samples in a temperature range of 27-43°C, corresponding to melting and crystallization of the eicosane in the structure of the composite fibers. It was shown that addition of the composites affects the dynamics of heating under the action of artificial sunlight and subsequent cooling: the samples with added fiber showed more intense heating and slower cooling compared with control samples when the temperature reached 35°C. Samples of the hardened mixture with addition of the composite fibers also exhibited the ability to accumulate thermal energy when exposed to a high-frequency alternating magnetic field with its subsequent sustained removal. [ABSTRACT FROM AUTHOR]

Biopolymeric materials appear as promising eco-friendly and biodegradable matrices for the preparation of composite materials. In this work, G. lucidum, T. hirsuta, P. eryngii, F. velutipes, G. applanatum, L. edodes, and H. erinaceus fungi strains were studied and the fastest-growing fungi strains were revealed. The growth rate and the morphology of formed mycelium were studied depending on the fungi strain type and employed feeding substrate (malt agar, cellulose microcrystals, cellulose microfibrills). It was shown that the mycelium of G. lucidum and T. Hirsuta grown on cellulose microfibrils appears as intertwined hyphae with narrow diameter size distribution and has an optimal morphology as a substrate for the preparation of fibrous composite materials.. [ABSTRACT FROM AUTHOR]

Guar gum is a polymer that is widely used as a gelling agent for technological liquids in the petroleum industry. In this work, we have studied the potential for the environmentally friendly biodegradation of guar gum by enzymes of basidiomycetes for efficient disposal of oil industry wastes. We compared the enzymatic activity against guar gum of seven basidiomycete strains for the first time, namely Trametes hirsute MT-24.24, Lactarius necator, T. hirsute MT-17.24, Schizophyllum commune MT-33.01, Fomes fomentarius MT-4.05, Fomitopsis pinicola MT-5.21, and T. versicolor It-1. This comparison showed that the preparation based on the Fomitopsis pinicola MT-5.21 fungal mycelium at a concentration of 0.05% provides the most efficient decomposition of a hydraulic fracturing fluid containing guar gum. By varying the enzyme concentration in this fluid, it is possible to control the decrease in its viscosity over time. The developed enzyme preparation is an efficient and environmentally friendly guar gum biodegrader and can serve for processing waste fracturing fluids based on polysaccharides in order to reuse water resources. [ABSTRACT FROM AUTHOR]

In this work, we synthesized samples of carboxylated nanofibrillar cellulose (NFC) and a derivative that is a product of chemical crosslinking of carboxylated NFC with ethylenediamine. The results of transmission electron microscopy revealed that crosslinking does not lead to noticeable morphological changes in the NFC structure. The chemical modification of the carboxylated NFC was confirmed by FTIR spectroscopy. It was found that chemical crosslinking of carboxylated NFC with ethylenediamine leads to an increase in the colloidal stability of aqueous suspensions, water retention capacity, and dynamic viscosity of gels. The study of the rheological characteristics showed that the aqueous dispersions of the obtained samples are pseudoplastic liquids and have thixotropic properties. [ABSTRACT FROM AUTHOR]

A new high light yield liquid scintillator based on linear alkylbenzene (LAB) as an organic solvent and a novel nanostructured organosilicon liminophore as a scintillation fluor has been developed for the next generation large-scale experiments in astroparticle physics. It is shown that the developed liquid scintillator has light yield almost two times higher than traditional LAB-based liquid scintillator with PPO fluor, when peak light yield values are compared, since the former peaks at 490 nm, while the latter peaks at 360 nm. At the same time light emission kinetics is characterized by about 10 ns decay time constant for its fastest component which contributes more than 80% to the total light yield of the scintillator. [ABSTRACT FROM AUTHOR]

High-energy cosmic-ray research via the detection of Cherenkov radiation from extensive air showers was begun in the Tunka valley (50 km to the west from the southern extremity of Lake Baikal) in the early 1990s. A series of large arrays combined into the TAIGA (Tunka Advanced Instrument for cosmic-ray physics and Gamma Astronomy) astrophysical facility and designed to study gamma rays and charged cosmic rays have been created in the elapsed time. Descriptions of the facility arrays and the main results obtained while investigating high-energy cosmic rays are presented. Plans for a further development of the astrophysical facility are discussed. [ABSTRACT FROM AUTHOR]

A study is made of the astroclimatic conditions for performing nighttime astrophysical observations on the territory of the Greater Altai region. Nighttime data from both the VIIRS radiometer of the Suomi NPP satellite platform and the AIRS hyperspectrometer of the Aqua satellite are used. Topographic and astroclimatic criteria show that the Chuya steppe region (Altai Republic, Russia) and the plateau of Lake Khubsugul (Aimak Khuvsgel, Mongolia) are best suited for the deployment a full-scale gamma astronomy experiment. Infrastructure considerations make the territory in the western part of the Chuya steppe preferable. [ABSTRACT FROM AUTHOR]

The prototype of a small wide-angle telescope was installed within the astrophysical complex TAIGA in the Tunka Valley in September 2019. Data were collected on the prototype's performance during the last eight observation sessions. Operating regimes of the telescope's systems, the trigger system, and the system for synchronizing with the TAIGA complex were tested. The first results from analyzing data on the prototype telescope's performance are presented. [ABSTRACT FROM AUTHOR]

The TAIGA hybrid gamma-ray observatory is currently being developed in the Tunka Valley, 50 km from Lake Baikal, to study gamma radiation and charged cosmic ray fluxes in the 1013–1018 eV range. The first results are presented for detecting gamma rays from the Crab Nebula in 44 h of observation, and from the blazar Markarian 421 in 62 h of observation with a significance of around 5–6 σ by one of the TAIGA IACT telescopes. [ABSTRACT FROM AUTHOR]

The astrophysical complex TAIGA (Tunka Advanced Instrument for cosmic-ray physics and Gamma-ray Astronomy), whose first phase is being completed in the Tunka valley 50 km from Lake Baikal, is described. Its research program, first results, and development prospects are discussed. [ABSTRACT FROM AUTHOR]

The uniform broadening of spectral lines associated with the quantum transitions of room-temperature trionic states localized in traps on nanoscaled surface defects within the crystal structure of a three-layer Si(P)/Si(B)/ZnO film is investigated experimentally using the phonon echo approach. [ABSTRACT FROM AUTHOR]

A corrected energy dependence of the depth of the maximum in the wide range of energies 1015 to 1018 eV is obtained using data collected at the Tunka-133 facility over 7 years of operation (2009–2017) and the TAIGA-HiSCORE facility in the 2019–2020 season. At the highest energies, our results match those of the Pierre Auger observatory. The results are converted to parameter ❬ln A❭, which characterizes the mean EAS composition. [ABSTRACT FROM AUTHOR]

Abstract: A process has been described for obtaining polymer (polyelectrolyte) microcapsules and polyelectrolyte/magnetite composite microcapsules, as well as silica-based hybrid capsules via silane-type precursor hydrolysis, which gives rise to the formation of silica nanoparticles in the structures of shells containing different numbers of polymer layers. The polymer and nanocomposite microcapsules have been formed by successive adsorption of oppositely charged polyelectrolytes and/or nanoparticles on the surface of microparticles of vaterite, which is a polymorphous modification of calcium carbonate. The obtained shells of microcapsules of all types have been studied by atomic force microscopy, confocal fluorescence microscopy, and scanning electron microscopy before and after sonication. The effect of high-intensity focused ultrasound on the obtained samples of microcapsules has been investigated and the sonication parameters that ensure efficient disruption of their shells in an aqueous medium have been determined. It has been found that composite microcapsules containing magnetite nanoparticles in their shells are most sensitive to sonication. The obtained composite microcapsules are promising for developing new systems for delivery of biologically active substances and multifunctional coatings. [ABSTRACT FROM AUTHOR]

The Navier-Stokes equations were used to carry out the numerical modeling of chemically reactive gas flow in an annular flow chamber. The model was based on laws of conservation of mass, momentum, and energy for nonstationary two-dimensional compressible gas flow in the case of axial symmetry with a tangential component of the gas velocity. Viscosity, thermal conductivity, and turbulence were taken into account. Fuel and oxidizer were fed into the chamber separately, and heat release in the chemical reaction zone was largely determined by the rate of turbulent mixing of the gas components. The possibility of burning out of the mixture in the chamber was demonstrated numerically. Detonation failure can occur if reagents temporarily cease to be fed into the chamber, which can be caused by high pressure in the reaction zone. With short combustion chamber lengths, there are the underburning of fuel and the release of unreacted hydrogen into the atmosphere. [ABSTRACT FROM AUTHOR]

The results of an experimental investigation and numerical modeling of the most likely high-wear zones in 90° pipeline bends in the pulsed pneumatic conveyor system at the RT-1 plant of the Mayak Industrial Association are presented. The experimental studies were conducted on a model of a pulsed pneumatic conveyor system; the numerical modeling of the gas-dynamic flow in the pipeline channel was performed in a model of a two-dimensional non-stationary motion of a compressible medium. It was found on the basis of the experimental results obtained using the model and numerical modeling in the homogeneous approximation that local regions with high wear of walls in the 90° pipe bends in the pulsed pneumatic conveyor do indeed exist and their experimentally found positions agree with the calculations. [ABSTRACT FROM AUTHOR]

This paper describes the numerical modeling of gas flow in a plane vortex chamber by using the Navier-Stokes equations. The model is based on the laws of conservation of mass, momentum, and energy for nonstationary two-dimensional compressible gas flow in the case of axial symmetry with a tangential component of the gas velocity. The processes of viscosity, thermal conductivity, and turbulence are accounted for. It is shown that the transition of the kinetic energy of gas into thermal energy as a result of transfer processes leads to the formation of hot spots in the boundary layers near the walls of the chamber. The gas temperature at these hot spots can exceed the gas combustion temperature, while the gas remains rather cold in the neighboring regions. This could be the reason for the cold gas self-ignition observed in the experiments. The turbulence of the flow and the processes of mixing and diffusion of the components make a significant contribution to the capacity of gas self-ignition. [ABSTRACT FROM AUTHOR]

The spectral representation for the neutrino propagator in moving matter with a constant density has been derived. It has been found that matter includes a four-dimensional axis of complete polarization and all poles of the propagator are classified in terms of the projection of the spin on this axis. [ABSTRACT FROM AUTHOR]

The Tunka-Grande array is part of an experimental complex located in the Tunka Valley (Republic of Buryatia, Russia) about 50 km from Lake Baikal. This complex also contains the Tunka-133 and Tunka-Rex arrays. The aim of this complex is to study the primary cosmic ray energy spectrum and mass composition in the energy range of 1016–1018 eV, and to search for diffuse gamma rays in the energy range of 5 × 1016–5 × 1017 eV. The design of the Tunka-Grande array and the procedure for reconstructing the parameters of extensive air showers (EASes) are described, and preliminary results are presented from the search for diffuse gamma rays with energies of more than 5 × 1016 eV. [ABSTRACT FROM AUTHOR]

The Tunka-Grande scintillation array is described. The first results from its operation are presented. The prospects for studying primary cosmic rays in the energy range of 10 to 10 eV during simultaneous registration of the Cherenkov and charged particle components along with radio emissions from extensive air showers are discussed. [ABSTRACT FROM AUTHOR]

We describe the preparation of multilayer composite coating comprising nanoparticles of magnetite on metal substrates previously modified by sonication. Using the Brillouin light-scattering method, we have investigated the spectral characteristics of thermal magnons in these films as a function of the number of layers and the external magnetic-field strength. [ABSTRACT FROM AUTHOR]

A method of decontaminating the inner surface of pulsed pneumatic conveyer lines by removing contaminated metal by blowing an abrasive (liquid-free decontamination) is examined. The results of a study of the removal of a surface layer of metal as a function of the abrasive materials used are presented. These investigations were performed on a 1:7 scale pulsed pneumatic conveyer model. [ABSTRACT FROM AUTHOR]

Interaction of a single chemically active bubble in water with acoustic waves is numerically studied within the framework of the model of a two-dimensional unsteady flow of an ideal compressible medium. The boundaries between the phases are explicitly identified. It is demonstrated that bubble explosion initiation can be determined by the character of bubble deformation. Nonsphericity of deformation and jet formation lead to an explosion even if the bubble does not collapse. The possibility of the bubble explosion in an expansion wave, transfer of detonation from one bubble to another, and, thus, emergence of bubble detonation is demonstrated. [ABSTRACT FROM AUTHOR]

Results are presented from a study of the composition and structure of the bacterial oxidation zone in the sulfide minerals pyrrhotine, sphalerite, and galena in a sulfuric acid solution. The biochemical reactions that occur at the phase boundary are shown. The studies were conducted in the Department of the Beneficiation of Ores of Nonferrous and Rare Metals at the Moscow State Institute of Steel and Alloys. Theoretical studies were also performed and technologies were developed for the bacterial leaching of sulfide ores and concentrates. [ABSTRACT FROM AUTHOR]

In this work, a comparative study of the structure of symbiotic bacteria Wolbachia (strain wMelPop decreasing the fly lifespan) in genotypically different Drosophila melanogaster, as well as the effect of the bacteria on the host cell ultrastructure was investigated out. As a result of special crossings, the Drosophila melanogaster [w] Trl 362 and [w] Trl en82 lines, which are carried of mutations for the gene Trithorax-like, are synthesized (lines infected with Wolbachia are designated as [w]). The Drosophila melanogaster line free of Wolbachia was obtained by treatment with antibiotics of the initially infected [w] w 1118 line. The complex of the used methods and approaches has allowed us to perform a comparative study of the morphology of cell structures for the first time before and after the infestation of insects with bacteria and to evaluate effect of the bacteria on viability and fertility of flies of these lines. Electron microscopy analysis has shown that the embryos of the analyzed lines contain typical Wolbachia in contact with various host cell compartments; the ultrastructural organization of the bacteria indicates the preservation of their functional activity. In the cytoplasm of embryos that are mutant for the gene Trithorax-like, morphologically atypical mitochondria were revealed, as well as Wolbachia (wMelPop) of unusual morphology with a modified form of membtane envelopes. The presence of Wolbachia in ovarian cells of the female mutant fly lines has been found to produce no effect on the amount of the female-ovipositioned eggs. It has been established for the first time that lifespans of the infected and Wolbachia-free Drosophila melanogaster mutant lines TM3 containing chromosome 3 as a balancer are equal. However, it is significantly shorter in the imago of the [w] w 1118 line than in flies of the mutant lines. This has allowed us to suggest that either the chromosome-balancer TM3 or mutation of the gene Trl play an important role in the host-symbiont interactions. On checking this suggestion, it was found that the lifespan of homozygotes [w] Trl 362 and [w] Trl en82 after the infection of flies with bacteria decreased markedly and was close to the lifespan of [w] w 1118 line. The obtained data indicate that the chromosome-balancer TM3 can have a significant effect on the symbiont-host interaction. [ABSTRACT FROM AUTHOR]

Electron microscopic analysis of Drosophila melanogaster (w1118) ovarian cells has shown that stressful heat treatment of flies causes the appearance of electron-dense granules and large lysosomes in the cytoplasm of ovarian cells. These changes are not due to the presence of the endosymbiotic bacteria Wolbachia, as these changes were observed in both infected and uninfected flies. Essential envelope disturbances and other structural alterations have been revealed in the bacteria present in the ovarian cell cytoplasm of the flies. Some of the fly embryos died after heat shock; however, the bacteria retain their typical morphology in survived embryos. Endosymbionts did not change their localization in ovarian cells and in early fly embryos; they closely interacted with mitochondria and endoplasmic reticulum after the heat-shock treatment of flies. The performed study has shown that the high temperature affects both the host and the endosymbiont, but does not change the character of their structural interaction. [ABSTRACT FROM AUTHOR]

This review describes and discusses new data on the structure and function of proteins that contain ankyrin-like repeats in their structure. These proteins were found in cells of different organisms, but they do not belong to the cytoskeletal proteins. Many important functions of such proteins are provided by ankyrin repeats, which maintain protein-protein interactions that are involved in the formation of transcription complexes, the initiation of immune responses, biogenesis and the assembly of cation channels in the membranes, the regulation of some cell-cycle stages, symbiotic interactions, and many other processes. Mutations in genes that encode ankyrin-like proteins can cause defects in gene expression leading to onset and progression of many human and animal diseases; therefore, the structure, dynamics, and function of these proteins are objects of intensive study in modern biology. [ABSTRACT FROM AUTHOR]

The problem of the passage of acoustic waves in the neighborhood of a gas bubble in a tube is formulated and solved numerically. The main parameters determining the bubble dynamics in a non-stationary field are determined. The mechanism of jet deformation of the bubble followed by jet fragmentation and formation of a secondary small-size bubble fraction is studied. A possible explanation of the nature of local sonoluminiscence is proposed. [ABSTRACT FROM AUTHOR]

Wave interaction of bubbles in a cavitation cluster is studied theoretically and experimentally. It is found that two groups of bubbles with different phases of oscillations and collapse time are formed at the early stage of bubble‐cluster formation. It is shown that small bubbles accumulating energy in the initial pulsed acoustic wave collapse in the field of internal positive pressure of the cluster. A secondary compression wave generated by inertial expansion of large bubbles is determined by means of numerical simulation and registered experimentally. The amplitude of this wave is comparable to the amplitude of the initial pulse. A decrease in the oscillation period and strengthening of the microbubble collapse are observed in the cluster under pulsed compression. [ABSTRACT FROM AUTHOR]

The two dimensional inviscid nonstationary flow behind a shock wave passing through solid uranium dioxide or carbide particles suspended in liquid iron was simulated numerically. Such layers can appear inside planets in the vicinity of the planet's solid core. Shock waves passing in the interior of a planet (resulting from a possible asteroid impact on the planet) can change parameters of the layer. The calculations demonstrated that the local particle massconcentration behind the incident and reflected shock waves increases considerably, which can cause a transition of the layer into a supercritical state and a nuclear explosion inside the planet. The problem was solved taking into account possible particle collisions and their deformation and fission as well as changes in the fields of major thermodynamic parameters inside and outside each particle. [ABSTRACT FROM AUTHOR]

The growth dynamics of fractal aggregates was studied within the framework of continuum model in the self-consistent mean field approximation. The regime that is intermediate between the diffusion-limited aggregation and reaction-limited aggregation was considered. The dependence of aggregate fractal dimension on the attachment probability of particles during their collisions with an aggregate was obtained. In the limiting cases, the values of fractal dimension coincide with those determined earlier. The domain of the values of attachment probability was revealed where several regions characterized by their own values of fractal dimension were specified in the structure of growing cluster. Physical nature of the emergence of various regions in the aggregate structure was discussed. [ABSTRACT FROM AUTHOR]

The existence of solutions of the traveling–wave type is studied for a system of equations that describes a one–dimensional motion of a suspension of evaporating particles in a viscous and heat–conducting chemically reacting gas. Using topological methods, it is shown that solutions corresponding to weak, strong, and Chapman—Jouguet detonation exist under certain restrictions on energy release and mass transfer. [ABSTRACT FROM AUTHOR]

The emergence and development of a viscous, thermally conducting, compressible boundary layer behind a shock front in a tube is investigated numerically. The reverse effect of the boundary layer on the inviscid flow in the center of the tube is studied. It is shown that, in order to account for the effect of the tube walls on the external flow, nonstationary boundary layers must be computed, since averaging the losses over the transverse cross section of the tube may be too crude an approximation. [ABSTRACT FROM AUTHOR]

We construct a spectral representation of neutrino propagator in moving matter or in external magnetic field. In both cases there exists fixed four-dimensional axis of polarization, such that the corresponding spin projectors commute with propagator. As a result, all eigenvalues of propagator and, consequently, dispersion laws for neutrino in media are classified according to spin projection onto this axis. Use of the found spin projectors simplifies essentially the eigenvalue problem and allows to build spectral representation of propagator in moving matter or external magnetic field in analogy with the vacuum propagator. [ABSTRACT FROM AUTHOR]