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Showing papers by "Russian Ministry of the Emergency Situations published in 2019"


Journal ArticleDOI
30 Sep 2019
TL;DR: In this paper, the authors developed a procedure for the practical implementation of the emergency response method aimed at depositing hazardous radioactive substances from the atmosphere that enter the atmosphere during man-made accidents at nuclear power plants and other facilities for the storage and processing of radioactive materials.
Abstract: Studies of the response to nuclear emergencies with the release of gaseous and dispersed radioactive substances into the atmosphere allowed us to develop a procedure for the practical implementation of this method. The emergency response method is aimed at depositing hazardous radioactive substances from the atmosphere that enter the atmosphere during man-made accidents at nuclear power plants and other facilities for the storage and processing of radioactive materials. The developed procedure with the proposed algorithm of actions operates within the framework of a unified state system of civil protection. The presented procedure allows solving three main tasks on the elimination of emergency consequences: monitoring of the affected area, taking effective management decisions and direct influence on the affected area. The basis for making effective management decisions is to predict the dynamics of radioactively contaminated areas, predict the intensity of precipitation with various methods of artificial deposition and predict the effectiveness of deposition effects on the dynamics of changes in contaminated areas. In order to expand the capabilities of available methods for predicting contaminated areas, their modification has been proposed taking into account deposition features. The use of this procedure allows minimizing the scale of major emergencies at regional and state levels. Due to the use of artificial deposition methods, as provided for in the procedure, there is the possibility of depositing dangerous radioactive substances from the atmosphere from a height of several kilometers, which cannot be implemented by other known methods. The developed algorithm of actions and the procedure for implementing the emergency response method by artificially initiated deposition are the basis for the development of a procedure for practical emergency rescue units during emergency response at regional and state levels. Thus, there is a reason to believe that the use of the proposed procedure will improve the efficiency of response to man-made emergency with the release of hazardous radioactive substances to the atmosphere.

7 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of the amorphous transition layer at the interface between Mn4Si7 and silicon doped with manganese on the photoelectric properties of heterostructures is considered.
Abstract: The effect of the amorphous transition layer at the interface between Mn4Si7 and silicon doped with manganese on the photoelectric properties of heterostructures is considered. It is found that the precipitated Mn atoms on the silicon surface are grouped at high temperatures, forming drops of liquid manganese, which dissolve the near-surface layer of silicon, forming a liquid solution-melt of Mn with Si. As the solution solidifies, Mn4Si7 forms, and the Si–Si bonds under the silicide break due to intense diffusion of Si atoms; an elastically deformed Si region forms, which predetermines the evolution of the formation of photoelectric phenomena in the Mn4Si7–Si❬Mn❭–Mn4Si7 and Mn4Si7–Si❬Mn❭–M heterostructures. The microstructure and chemical composition of doped Si❬Mn❭ samples were studied by means of scanning electron microscopy and X-ray energy dispersive spectrometry using a Quanta 200-3D microscope, and the interface structure of the higher manganese silicide (HMS) and Si❬Mn❭ layer at the nanoscale was refined using the Fourier transform of local zones of high-resolution electron-microscopic images. It is concluded that in the process of diffusion doping of silicon with manganese, broken layers on the surface of the crystal deepen the embedding of manganese atoms, facilitate adsorption, dissolution, and diffusion of Mn in the volume of Si, and also enable the formation of an amorphous layer at the interface of higher manganese silicide and the Si❬Mn❭ layer. The presence of an amorphous transition layer facilitates the process of impact ionization of current carriers upon application of external voltage, as well as the formation of photoelectric phenomena: infrared quenching, temperature quenching, high photosensitivity, and long-term relaxation of residual conductivity.

5 citations


Journal ArticleDOI
29 Jun 2019
TL;DR: In this article, a comparative analysis of the calculated and experimental values of the ultimate compressive strength for samples based on the copper matrix and carbon nanotubes was performed, and the results of the analysis were used in the development of new antifriction composite materials with improved strength properties.
Abstract: Carbon nanotube (CNT)-reinforced powder nanocomposites based on copper matrix were successfully fabricated using a spark plasma sintering method. In this work, the mechanisms of hardening the metal matrix with nanosized filler particles were shown. A comparative analysis of the calculated and experimental values of the ultimate compressive strength for samples based on the copper matrix and carbon nanotubes was performed. Linear and root-mean-square models of hardening of composite materials with nano-sized filler were presented. The root-mean-square model allowed us to calculate reliably the values of the ultimate compressive strength at a concentration of CNT in the material up to 0.07 wt.%. The ultimate compressive strength decreases sharply when the content of CNTs in the material is more than 0.07 wt.%. The Orovan mechanism is the predominant mechanism of strengthening of composite materials: copper – CNT. The predominance of Orovan mechanism over other strengthening mechanisms is explained by the relatively low transfer efficiency of the load between the initial components of the material due to the weak interfacial connection between the matrix and the filler, the insufficiently uniform distribution of CNTs in the metal matrix, the agglomeration of nanosized filler, the location of a certain number of CNTs in the pore space of the metal matrix, the presence of pores of irregular shape. The results of the work were used in the development of new antifriction composite materials with improved strength properties for friction units of machines and mechanisms for various purposes.

4 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of the metal matrix filling with carbon nanotubes on the thermal properties of copper-based powder composite materials has been studied and it has been shown that at a CNT concentration below the percolation threshold, experimental values of the thermal conductivity coefficient of the composite materials are in good correlation with the values obtained with the Maxwell-Garnett theoretical model.
Abstract: The influence of the metal matrix filling with carbon nanotubes on the thermal properties of copper-based powder composite materials has been studied. It has been revealed that the powder systems ″copper–CNTs″ obtained according to the powder-metallurgy technology by electric-contact sintering possess anisotropic thermal conductivity under certain conditions. It has been found that during uniaxial molding, in the process of electric-contact sintering, CNTs are oriented in one direction, which leads to a rise in the values of the thermal-conductivity coefficient in this direction. It has been established that at a CNT concentration below the percolation threshold, experimental values of the thermal-conductivity coefficient of the composite materials are in good correlation with the values obtained with the Maxwell–Garnett theoretical model. It was noted for the first time that the Maxwell–Garnett theoretical model can be used to assess the distribution of a nanosize filler in a metal matrix.

3 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the absorption, fluorescence, and phosphorescence spectra of metal complexes of 4-tert-butylphenyl-substituted tetra(1,4-diazepino)porphyrazine MPADz4Ph8′ (M = Mg, Zn; PA = porphyrazines; Dz = diazepine; Ph = phenyl; Ph′ = 4-TERT-butylonphenyl) were recorded in DMF at 293 and 77 K.
Abstract: Absorption, fluorescence, and phosphorescence spectra of metal complexes of 4-tert-butylphenyl-substituted tetra(1,4-diazepino)porphyrazine MPADz4Ph8′ (M = Mg, Zn; PA = porphyrazine; Dz = diazepine; Ph = phenyl; Ph′ = 4-tert-butylphenyl) were recorded in DMF at 293 and 77 K. The Q(0–0) absorption bands of MgPADz4Ph8′ and ZnPADz4Ph8′ did not show signs of splitting, i.e., corresponded to the monomeric form. Singlet–triplet gaps of 4700 cm–1 for the Mg complex and 4800 cm–1 for the Zn complex were determined from fluorescence and phosphorescence spectra. Fluorescence quantum yields and lifetimes were measured. Rate constants of S1,2 → S0 radiative transitions and total rate constants of nonradiative deactivation of the S1,2 states were determined. Internal conversion rate constants were estimated. Conformer geometries of MgPADz4Ph8 (in the 6H tautomeric form) were calculated by density functional theory in the PBE/TZVP version. The conformer of symmetry S4v (D2d ) had the lowest energy. Nonplanar diazepine rings induced small but perceptible out-of-plane distortions in the central porphyrazine ring of MgPADz4Ph8. This feature correlated with the observed Stokes shifts of 400 and 350 cm–1 (at 293 K) for MgPADz4Ph8′ and ZnPADz4Ph8′ whereas the metal phthalocyanines had shifts of ~50 cm–1. Excited electronic states of MgPADz4Ph8 were calculated using INDO/Sm. The Q-state energy of 15,200 cm–1 agreed well with the observed value of 14,800 cm–1. Strong featureless absorption in the range 330–450 nm (Soret band analog) with maxima at ~25,000 and ~29,000 cm–1 was due mainly to two strong electronic transitions with calculated energies of 24,100 and 31,500 cm–1; a shoulder on the long-wavelength side of the Soret band at ~23,000 cm–1, to a transition of calculated energy 23,800 cm–1.

2 citations


Journal ArticleDOI
TL;DR: Natural antioxidants, drugs, nutritional supplements as radiomodulators, high-quality nutrition including vegetable products enriched with flavonoids and vitamins C and E, and carotin potentially promote prevention of accelerated aging in astronauts during long flights under the influence of solar and galactic cosmic rays and space flight stress factors.
Abstract: The radiation risk for astronauts in long space flights depends on the impact of low-intensity galactic and solar radiation on the spaceship. There is a small possibility of high solar activity during long space flights, which can threaten astronauts with doses causing deterministic radiation effects. B-190 (indralin) is the most promising radioprotector of the small number of radioprotective drugs allowed for use in humans. The antiemetic Latran (ondansetron) is of interest for prophylaxis of, and stopping the primary radiation response. Application of radiomitigators during proton radiation makes it possible to accelerate post-radiation recovery processes in hematopoietic tissue. Neupomax has been suggested for pathogenetic therapy of acute radiation illness. Natural antioxidants, drugs, nutritional supplements as radiomodulators, high-quality nutrition including vegetable products enriched with flavonoids and vitamins C and E, and carotin potentially promote prevention of accelerated aging in astronauts during long flights under the influence of solar and galactic cosmic rays and space flight stress factors.

2 citations


Journal ArticleDOI
TL;DR: In this paper, a model of these composites based on epoxy oligomers and aluminum oxides capable of the evaluation the wear rate of the material without using a friction machine was proposed.
Abstract: Due to the complex of their physicomechanical and operating characteristics, the composite materials based on thermosetting polymers are extensively used in all branches of Ukrainian industry for the corrosion and wear protection of the equipment and, in particular, as antifriction materials. We propose a model of these composites based on epoxy oligomers and aluminum oxides capable of the evaluation the wear rate of the material without using a friction machine. For this purpose, we apply the similarity theory. According to this theory, in the case where all corresponding dimensionless characteristics of two different processes are identical, these processes are similar. On the basis of the experimental data obtained in analyzing the friction coefficient, the elasticity modulus, and the hardness of epoxy composites, we propose a model for the prediction of the wear characteristics of materials depending on the content of aluminum oxide. The application of this model guarantees the agreement between the results of modeling and the experimental data.

1 citations


Journal ArticleDOI
TL;DR: In this paper, the relaxation and thermal processes and interphase phenomena in composites based on ferroelectrics and a polymer matrix are studied, and it is shown that the charge stabilized at the interface of the composite during its electrothermopolarization is mainly determined by the structure of the polymer matrix and the piezoelectric phase.
Abstract: The relaxation and thermal processes and interphase phenomena in composites based on ferroelectrics and a polymer matrix are studied. It is shown that the charge stabilized at the interface of the composite during its electrothermopolarization is mainly determined by the structure of the polymer matrix and the piezoelectric phase. The results obtained make it possible to reveal the main factors affecting the piezoelectric properties of the heterogeneous polymer–ferroelectric ceramic system. Polyolefins and fluorine-containing polar polymers are used as the organic phase, and ferroelectric ceramics of rhombohedral, tetragonal, and mixed structures serve as the inorganic phase. The relaxation processes and interphase phenomena are studied using a differential scanning calorimeter, and the charge state is analyzed by recording the thermally stimulated depolarization current. The charge-state stability is determined by the electret potential difference of the composites. The molecular relaxation is analyzed by the dielectric method. It is established that the composites in which the interphase interaction is more pronounced are characterized by high piezoelectric properties.

1 citations


Journal ArticleDOI
TL;DR: In this article, the results of field studies to determine the essential kinematic characteristics of the two-phase flow are presented, including the conditions of transporting the solid particles, the efficiency of their application in cutting as well as the assessment of energy losses.
Abstract: Introduction. In waterjet cutting, a two-phase flow consisting of water and abrasive solid particles moves at a high average speed. Destruction of hard materials and alloys requires a large force and, therefore, a high flow rate. Such flows differ utterly from natural and well-studied flows in hydraulic transport and hydroprocessing. Determination of kinematic characteristics in the waterjet cutting is an independent task. Materials and methods. The results of field studies to determine the essential kinematic characteristics of the two-phase flow are presented. The conditions of transporting the solid particles, the efficiency of their application in cutting as well as the assessment of energy losses. The revelation of features of the two-phase flows and differences from water flows is a part of engineering calculations aimed at the effectiveness of their use in various fields of activity, including firefighting. Results. The calculations of the two-phase flow heterogranularity, the weighted average density of the particles constituting the solid phase, the flow volume density, and actual flow density were carried out. Calculations of the two-phase flow density were performed by а volume-weight method and by integrating the solid particle density distribution in depth. Conclusions. The paper showed that in waterjet cutting the actual density exceeds the flow volume density by 8.5 % what is lower than the values recommended for hydraulic transport. All the engineering calculations must be conducted using the values of the actual flow density. The kinematic characteristics obtained in this work are the basis for the calculation of additional head losses per 1 meter of a firefighting unit hose during transportation.

1 citations


Journal ArticleDOI
TL;DR: In this article, a one-step procedure was developed for the synthesis of previously unknown ethyl 5-(aryl carbamoyl)-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylates by reaction of ethyl 2-cyano-3 -ethoxyprop-2 -enoate with acetoacetanilides in the presence of a catalytic amount of piperidine in ethanol at room temperature.
Abstract: A one-step procedure has been developed for the synthesis of previously unknown ethyl 5-(arylcarbamoyl)-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylates by reaction of ethyl 2-cyano-3-ethoxyprop-2-enoate with acetoacetanilides in the presence of a catalytic amount of piperidine in ethanol at room temperature.

1 citations



Journal ArticleDOI
TL;DR: Ethanol before irradiation did not significantly modify the state of neurons, but caused the appearance of synapses degenerating via filament type, and radio-modification depended on the dose of ethanol and the time of its administration.
Abstract: Cerebral effects were studied in experiments on rats exposed to acute γ-radiation of the head at cerebral doses, with previous or subsequent administration of different ethanol doses. Both factors cause similar changes in neurological symptoms and neuromorphological effects. Ethanol before irradiation did not significantly modify the state of neurons, but caused the appearance of synapses degenerating via filament type. After irradiation, ethanol at the threshold dose did not change and at a large tranquilizing dose slightly increased radiation changes in neurons and synapses. The effects of radio-modification depended on the dose of ethanol and the time of its administration.