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In this paper, the transport characteristics of two-dimensional systems has been investigated. Modeling by means of the Yukawa potential, in a wide range of values of the nonideality parameter, has been carried out. The Yukawa potential was chosen because of its wide applicability in the description of screened interactions in plasmas and other systems. A molecular dynamics method was used to determine the transport characteristics. The study was carried out with the aim of expanding the knowledge of heat transfer in two-dimensional systems. The paper presented the results of numerical experiments in which the dependences of the heat transfer and viscosity coefficients on the screening and non-ideality parameters in systems with Yukawa potential were studied. The obtained data can also serve as a basis for further theoretical and experimental studies in the field of transport characteristics of two-dimensional systems. These data not only expand the understanding of the peculiarities of two-dimensional systems, but also can be useful in the design and analysis of nanostructures and various microdevices. [ABSTRACT FROM AUTHOR]

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fluorine-doped detonation nanodiamond (DND) powders are considered as a new class of neutron reflectors and can significantly improve the performance of very cold and ultracold neutron sources, which in turn will lead to new types of experiments at a qualitative level. These improvements are achieved due to such properties of DND as high diffusion and quasi-mirror reflection. The high reflectivity improves the neutron delivery efficiency and, consequently, the neutron fluxes at neutron facilities. On this basis, fluorinated DNDs are considered as a potential neutron reflector material for the designed very cold and ultracold neutron source at the WWR-K reactor. However, to date, experimental data on the behaviour of fluorinated DND in the neutron field are insufficient, and therefore, in order to study the radiation resistance of DND at the WWR-K reactor, work has been started on their irradiation and further study. For this purpose, an optimal irradiation capsule design was developed and comprehensive calculations were performed to justify the conditions and limits of reactor irradiation. This paper describes the irradiated samples and reactor experiment, the methodology and conditions for irradiating the samples, and the results of their initial characterisation after irradiation. [ABSTRACT FROM AUTHOR]

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interest in beryllium-based composite materials has emerged recently, when intermetallic compounds such as titanium beryllide Be12Ti began to be considered as a promising material for neutron multiplication in thermonuclear fusion facilities, such as ITER and DEMO. Titanium beryllide stands out from other beryllides because it has the highest neutron multiplication rates and also has the added benefit of being more thermally stable than beryllium metal. Titanium beryllide interacts much weaker with water vapor, excluding the possibility of the formation of explosive hydrogen in the blanket body, is less prone to gas swelling, and, unlike metallic beryllium, retains a smaller amount of accumulated tritium. It has also been confirmed that the compatibility of titanium beryllide with structural materials is much higher than that of beryllium. To use titanium beryllide, it is important to study the parameters of its interaction with hydrogen isotopes. One of the most well-known methods for is the method of thermal desorption spectroscopy (TDS). The objective of this paper is the development of a specialized experimental setup for TDS research and the development of a methodology for performing experiments. The results of methodical experiments are presented, in which the procedures for saturation of samples in a deuterium medium and procedures for conducting TDS experiments were worked out. Methodical experiments on studying the parameters of the interaction of deuterium with samples of monolithic titanium beryllide were carried out on the material produced by Ulba Metallurgical Plant JSC, saturated in deuterium at atmospheric pressure and a sample temperature of 973 K. linear heating rates of 10 and 20 K/min. Based on the results of the development of the technique for conducting experimental studies of titanium beryllide, a differential mode of the TDS method was recommended. In this case, it is necessary to use a hydrogen isotope, deuterium, as a control probe. [ABSTRACT FROM AUTHOR]

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is difficult to overestimate the role and place of computational experiments in modern scientific research. Scientists investigate physical phenomena based on computer models and computational experiments when analytical methods of theoretical physics do not allow obtaining more reliable results. On the other hand, computational experiments can be carried out in conditions inaccessible to field experiments. The paper presents the scientific results of the study of some issues of celestial mechanics. These results are obtained on the basis of the use of computer methods. The MathCAD application software package is used as a programming language. The main scientific results include the following: a graph of the potential of the gravitational field of the Earth is constructed depending on the distance r to the center of the Earth; on the basis of a computer approach, the equations of the potential energy (binding energy) of the interaction of a body of a unit mass with the Earth-Moon system are studied; on the basis of computer methods, graphs are obtained. These graphs characterize the binding energies of the body depending on the coordinates of the radial axis; with the help of the MathCAD package, the flight path of the spacecraft near the Earth was modeled under various initial conditions; the motion of the spacecraft from the Earth to the Moon was studied and various types of flight paths were constructed depending on its initial velocity. [ABSTRACT FROM AUTHOR]

This paper presents the results of thermodynamic and experimental studies of plasma-thermal processing of ash with the production of fuel gas and inert mineral material are presented. Plasma-thermal processing of ash and slag wastes consists in their heating, pyrolysis and melting to remove residual carbon and obtain a neutral melt, the storage and use of which after cooling does not cause environmental problems. Ash from Ekibastuz coal, which is widely used in the energy sector of Kazakhstan, is taken as ash and slag waste, which is a set of components of the mineral mass of coal and unburned carbon. Calculations have shown that during the plasma-thermal processing of ash and slag waste, combustible gas is obtained with a CO concentration of up to 86.8% and a calorific value of 8752 kJ/kg and a melt of mineral components that does not contain harmful impurities. The plasma reactor is a melting chamber covered by an electromagnetic coil. The chamber has the shape of an equilateral triangle in section, with three inclined immersed graphite electrodes at its corners. The reactor was started up by shorting the power electrodes to a bulk graphite track. After obtaining the melt channel, the heating of ash and slag waste continues due to the conduction currents between the power electrodes through the resulting melt. To homogenize the melt, it is stirred electromagnetically. The melt productivity of the reactor was 100 kg/h at its temperature of 1923 K and specific energy consumption of 0.96 kW h/kg. Both in calculations and in experiments, no harmful impurities were found in the products of plasma processing of the investigated wastes. [ABSTRACT FROM AUTHOR]

When negatively charged particles are scattered by atomic nuclei before the thresholds of excitation of nuclei, the formation of a metastable system "charged particle + excited nucleus" is possible. In particular, during the scattering of μ-mesons by nuclei, mesoatoms with an excited nucleus in the states of the entire atomic spectrum of hydrogen-like atoms can arise. This infinite set of states of a quasi-bound system generates an infinite series of elastic scattering resonances in the continuous spectrum, which condenses to the threshold energy of the excitation of the nucleus. In cases where the elastic scattering widths of mesons are smaller than the decay width of the excited state of the nucleus, inelastic meson resonance decay channels arise, which make it possible to observe them experimentally in the process of resonant scattering. In the present work, an analytical expression is obtained for the widths of subthreshold resonances arising from the scattering of μ mesons by atomic nuclei. The widths of subthreshold resonances in such systems are explicitly expressed in terms of the reduced multipole matrix elements of nuclear transitions The paper presents estimates for dipole excitations of nuclei corresponding to the farthest resonant states. It is shown that modern meson facilities make it possible to directly determine the reduced matrix elements of dipole transitions in experiments on elastic meson scattering. For a group of nuclei with large widths of E1 γ-radiation, it is possible to set up an experiment to determine these widths, and for known widths, to determine the chemical composition of the target. [ABSTRACT FROM AUTHOR]

The paper considers the modernization of the methodology for studying astrophysical ice and cold interstellar dust. An experimental method of physical modeling using a vacuum cryogenic installation is presented. The nodes of the universal vacuum cryogenic spectrophotometer where it is necessary to modernize, retrofit for the subsequent improvement of measuring capabilities in scientific research are considered in detail. The IR spectra of polystyrene were obtained on the IRS-29 and FSM 2203 spectrometers, the results of the obtained characteristic absorption bands were compared with the values of the reference spectrum of polystyrene, and the expanded uncertainty was calculated. To assess the accuracy of the measurement results, we calculated the expanded uncertainty according to the IR spectrometer calibration procedure. The wavenumber scale calibration uncertainty was determined by direct measurements as the difference between the wavenumber value corresponding to the maximum ordinate of the absorption line of a standard polystyrene film sample. In this work, an analysis of the completed retrofitting of a universal vacuum cryogenic spectrophotometer was carried out. N2O spectra were taken, obtained at a temperature of 16 K in the wave number range of IR spectrometers from 370 to 4200 1/cm with the designation of the corresponding absorption bands. The studies carried out in this work are aimed at improving the accuracy of measurements, which guarantees and improves the quality of scientific research. [ABSTRACT FROM AUTHOR]

In this paper, a model of a pulsating universe is investigated with periodic function of the scale factor together with a homogeneous, isotropic and spatially flat Friedman-Robertson-Walker metric. The parameters of the pulsating universe model coincide with observation parameters of the modern universe, taking into account the different contributions of various types of matter to its evolution. In the resulting solution, during periods of accelerated expansion of the universe, the scalar field with negative pressure makes a greater contribution to the expansion growth. The fermionic field and the vector field, which have positive pressure values during this period, prevent the growth of this expansion. During periods of compression, the fermionic field and the vector field have a greater influence on the dynamics of the evolution of the universe. In the resulting periodic solution, the universe goes through endless cycles of expansion and contraction. The observed modern accelerated expansion of the universe corresponds to one of these cycles. Cosmographic parameters are calculated - parameters of deceleration q, jerk j and snap s and energy conditions for the model under research. These parameters make it possible to link model-independent results obtained from cosmography with theoretically sound assumptions of gravity. [ABSTRACT FROM AUTHOR]

This paper presents a study of the temperature distribution on a universal cryogenic surface when it is cooled to nitrogen temperatures. Using computer simulation methods, in particular the finite element method, it was possible to determine the temperature-time dependences that occur during the cooling of a surface using the heat exchange tubes of different diameters located inside the surface at equal distances from each other. By varying the diameter of the heat exchange tubes, its effect on the cooling intensity was revealed when examining the volumetric temperature distribution: a larger diameter of the heat exchange tube yields a more uniform cooling of the surface. Besides, a larger orifice diameter leads to reaching thermal equilibrium quicker over the entire surface examined. By using a 7 mm orifice diameter, thermal equilibrium was reached 70 seconds after the start of cooling while 5 mm and 3 mm orifice diameters reached temperature equilibrium after 90 and 100 seconds respectively. The results obtained will make it possible to produce cooling of higher quality when designing universal cryogenic surfaces by using heat exchange tubes with certain geometric parameters. [ABSTRACT FROM AUTHOR]

This paper presents the results of statistical analysis of ionospheric disturbances in the integral electronic content, NF, during the period of registration of the Faraday effect at the point of Almaty [43,20N; 76,90E] when receiving signals from the ETS-II satellite (Engineering Test Satellite Type-II), located in geostationary orbit [00N; 1300E], the radio beacon of which operated at a frequency of 136,112 MHz. The analysis of the classification characteristics of each specific event showed that perturbations in the integral electronic content can occur both with a positive (35 cases out of 83) and with a negative sign in (37 cases out of 83), as well as with a change of phases (with a change of sign) in the course of the perturbation. According to the start time, ionospheric disturbances tend to occur more often in the evening and at night, with a greater probability at 17 LT -22 LT. During the year, NF disturbances occur most frequently in the months of November, December, January, February, and March. A decrease in the number of ionospheric disturbances is detected based on the data on the integral electron content of the ionosphere during the period of high solar activity. The «disappearance» of storms in the integral electron content occurs approximately at F10. 7 > 180, which is probably due to the «saturation» effect in the ionosphere. [ABSTRACT FROM AUTHOR]

Concrete is one of the most common building materials that is used in many areas of human activity, from the construction of residential buildings to industrial buildings and more. In the nuclear power industry, concrete is used not only as a structural material, but also as a material for biological protection. Usually concrete mix consists of cement, coarse and fine aggregates, water and various additives. Based on the field of application of concrete, the correct ratio of its components is selected. This paper presents the results of a study of the effect of the composition of concrete on its internal structure. The studies were carried out by the non-destructive method of neutron radiography and tomography at the facility, which is located on one of the horizontal channels of the WWR-K reactor. As a result of the studies carried out by the non-destructive method of neutron radiography and tomography, concrete samples of three different types of brands were studied. The distribution of pores and cracks in each sample is shown. The attenuation coefficients of neutron radiation for the studied concrete grades are given. The rate of water migration in concrete of different grades is estimated. The applicability of the neutron radiography and tomography installation for this type of investigation of the internal structure of concrete was demonstrated. [ABSTRACT FROM AUTHOR]

Copyright of Recent Contributions to Physics is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)