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Eurasian Journal of Physics and Functional Materials

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Vol 6, No 3 (2022)
165-173 212
Abstract

We investigate the Coulomb breakup of the 11 Be halo nuclei on a lead target within non-perturbative time-dependent approach in a wide range of beam energy (5–70 MeV/nucleon) including the low-lying resonances in different partial and spin states of 11 Be. We have found considerable contribution of the low-lying resonances ( 5/2+ , 3/2− and 3/2+ ) to the breakup cross section of 11 Be. The obtained results are in good agreement with existing experimental data at 69 MeV/nucleon. The developed computational scheme opens new possibilities in investigation of Coulomb, as well as nuclear, breakup of other halo nuclei on heavy, as well as, light targets.

174-179 150
Abstract

This paper presents the results of ternary light charged particles from 252Cf spontenous fission source. The method DeltaE - E was applied to identify the particle by a position sensitive DeltaE - E telescope.The specific energy loss (DeltaE) was measured using the transmission type DeltaE detector (thicknesses of 150 μm ) ordered from the company Micron Semiconductors, while the residual energy (E) was measured by a Timepix detector with thicknesses of 600 μm . It was possible to measure partial-energy spectra of the various ternary particle types due to the thicknesses of Al foil (31 μm) and DeltaE detector (150 μm) placed before E detector. The energy spectrum of protons was qualitatively different from the spectra of the other particles since protons from Al(n,p) and Si (n,p) reactions could contribute to the spectra.

180-189 207
Abstract

The structural characteristics and phase composition of several ancient brass ingots obtained in the archeological Shcherbet complex has been studied using neutron diffraction and tomography methods. The XRF analysis and neutron diffraction provide high zinc content up to 30 wt.%. The neutron tomography yielded 3D data of the spatial distribution of chemical elements in the brass alloy of the studied ingots, as well as inner voids and cavities as a possible result of the gas output during casting process. The patina, as a cuprite phase, occupy volumes to 8 % of the volumes of the ingots.

190-197 117
Abstract

The paper describes an experience of the IVG.1M research reactor operation with the core water-cooling system, which includes an auxiliary reactor coolant cooling system, designed for forced coolant cooling in periods of long-term reactor shutdown. The IVG.1M reactor is cooled by a limited amount of coolant circulating in a closed circuit, heated and uncooled during reactor operation. In this regard, duration of continuous operation of the reactor and frequency of startups are restricted due to limited value of water temperature at the core inlet. Prior to commissioning of the reactor coolant cooling system, it was cooled by means of natural heat transfer to the environment, while full-scale reactor startups were conducted with a frequency of approximately once per month. With forced coolant cooling, provided by use of the reactor coolant cooling system, its temperature decreases to acceptable values approximately within a week after the next startup, and, accordingly, full-scale startups of the IVG.1M reactor can be conducted once a week. This significantly expands potential of using the reactor and at the same time accelerates burnup of nuclear fuel and decrease in the reactor reactivity margin. Estimation of the fuel burnup rate will allow organizing timely supply of fresh fuel to replace the burnt out fuel. The paper contains the measurement results of the coolant temperature after a series of reactor startups, based on which it can be concluded that the IVG.1M RCCS has an effect on reducing the reactor downtime time between startups. The obtained results can be used to select and justify options for implementing the reactor campaign and its fuel.

198-212 145
Abstract

The article presents the results of computational studies to substantiate the possibility of testing the fuel of the Multipurpose hYbrid Research Reactor for a High-tech Applications reactor (MYRRHA) in the Impulse Graphite research Reactor (IGR). A scheme for conducting experiments is proposed, which allows simulating the operating conditions of MYRRHA fuel elements in a wide range of changes in their thermohydraulic parameters, including the conditions of accidents with the destruction of fuel pellets, blocking the flow area and stopping the coolant flow. A method for thermohydraulic calculations has been developed, implemented in the software environment of the computational fluid dynamics (CFD) code. A computational model of the experimental device is developed, optimized according to the spatial partitioning grid. A turbulence model for determining the parameters of convective heat and mass transfer in a eutectic lead-bismuth alloy is selected and substantiated.

213-222 140
Abstract

The elastic deformation energy accumulated at the edges of a fault in the earth’s crust in a seismically active area can be released with a small external impact, causing vibrations that propagate in the form of a sound wave through the lithosphere and can be detected on its surface. As a trigger effect that causes such a vibration, an ionization can be used that is created in the deep lithosphere by particles of the penetrating component of cosmic rays. This idea was once proposed in the number of theoretical studies. An experiment to test this hypothesis was started at the cosmic ray facility at the Tien Shan Mining Scientific Station. As a result, short-term sporadic acoustic emission signals were recorded by highly sensitive microphone detectors of the station. Presumably, the origin of this emission can be associated with seismic processes occurring in the area of a deep earth fault, located directly under the station. A statistically significant temporal correlation has been found between acoustic emission and high-energy cosmic ray muon events up to 100 TeV. If the further research in this direction is confirmed, then the effect of stimulated acoustic emission from a seismically active region of the earth’s crust may be of interest for solving the problem of short-term earthquake prediction.

223-233 146
Abstract

This article presents the results of a study of the electrochemical properties of cathodes based on polycrystalline samples of Na3Fe2(PO4)3 obtained by solid-phase synthesis and hot pressing. Factors affecting the electrochemical properties of cathodes based on Na3Fe2(PO4)3 obtained by solid-phase synthesis, hot pressing, and sol-gel are established. The prospects of using Na3Fe2(PO4)3 as a cathode material in sodium-ion batteries and the expediency of further modification of this compound in order to improve its electrochemical properties are substantiated.

234-243 144
Abstract

Ceramic coatings are used to protect against high-temperature oxidation of metal products. The efficiency of the technology of detonation spraying of two-layer coatings of aluminum oxide ( Al2O3 ) and a heat-resistant alloy (CoCrAlY) on the surface of a sample made of steel 12X18H10T was studied. A multi-chamber detonation unit was used in the work, providing high speed (up to 1000 m/s) and a 60–80% utilization rate of the sprayed material. We used an oxygen-neutral combustible mixture based on propane-butane. The coating material has a smooth gradient of properties from ceramic to sample substrate The complex of the obtained structural and physical-mechanical properties of the coating material makes it possible to predict its high performance under conditions of high-temperature oxidation.

244-250 150
Abstract

Various variations of the synthesis of ZnSe quantum dots are investigated. The influence of temperature, the concentration of precursors and the time of synthesis of quantum dots was taken into account. Aliquot absorption spectra is measured for various time intervals and the dynamics of the growth of ZnSe quantum dots is estimated. Luminescence and absorption spectra were obtained for purified quantum dots. Based on the experimental data, the nucleation time of quantum dots, optimal methods of synthesis and growth control is determent. HRTEM images showed the average size of ZnSe quantum dot, the calculated band gap is 2.84 eV.



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ISSN 2522-9869 (Print)
ISSN 2616-8537 (Online)