2020 год

№ Название статьи Авторы Название журнала Краткая аннотация Ссылка
1 Optimized single-axis schedule solar tracker in different weather conditions
 Kuttybay, N., Saymbetov, A., Mekhilef, S., Meiirkhanov, A., Svanbayev, Y. Nurgaliyev, M.

Energies

Q1 in Control and Optimization

 

 Improving the efficiency of solar panels is the main task of solar energy generation. One of the methods is a solar tracking system. One of the most important parameters of tracking systems is a precise orientation to the Sun. In this paper, the performance of single-axis solar trackers based on schedule and light dependent resistor (LDR) photosensors, as well as a stationary photovoltaic installation in various weather conditions, were compared. A comparative analysis of the operation of a manufactured schedule solar tracker and an LDR solar tracker in different weather conditions was performed; in addition, a simple method for determining the rotation angle of a solar tracker based on the encoder was proposed. Finally, the performance of the manufactured solar trackers was calculated, taking into account various weather conditions for one year. The proposed single-axis solar tracker based on schedule showed better results in cloudy and rainy weather conditions. The obtained results can be used for designing solar trackers in areas with a variable climate.

https://www.scopus.com/record/display.uri?eid=2-s2.0-85092933132&origin=resultslist&sort=plf-f

 
 2 Prediction of energy consumption for LoRa based wireless sensors network Nurgaliyev, M., Saymbetov, A., Yashchyshyn, Y., Kuttybay, N., Tukymbekov, D.

Wireless Networks

Q2 in Information Systems		 This paper shows a method for predicting the lifetime of a wireless sensor network based on the LoRa Ra-01 wireless modules. To develop a prediction model of the energy consumption, wireless sensor modules were assembled and it was obtained experimental data using LabView development environment. There were performed experiments to get battery discharge curve. Experimental data of power consumption depending on the packet length were obtained in transmission mode. Using experimental data, we obtained dependencies of system lifetime on sleep mode duration and packet length. The paper also considered a probabilistic approach to predict the system lifetime depending on the probability of data transmission during the day. The lifetime prediction model is based on Markov’s chains. The results obtained in this work can be used to predict lifetime of sensor networks more accurately. 

https://www.scopus.com/record/display.uri?eid=2-s2.0-85079789228&origin=resultslist&sort=plf-f
 3 Studies of the distinct regions due to CO selective dissociation in the Aquila molecular cloud Komesh, T., Baan, W., Esimbek, J., ...Rosli, Z., Ibraimov, M.

Astronomy and Astrophysics

Q1 in Physics and Astronomy		 Aims. We investigate the role of selective dissociation in the process of star formation by comparing the physical parameters of protostellar-prestellar cores and the selected regions with the CO isotope distributions in photo-dissociation regions. We seek to understand whether there is a better connection between the evolutionary age of star forming regions and the effect of selective dissociation Methods. We used wide-field observations of the 12CO, 13CO, and C18O (J = 1-0) emission lines to study the ongoing star formation activity in the Aquila molecular region, and we used the 70 and 250 μm data to describe the heating of the surrounding material and as an indicator of the evolutionary age of the core. Results. The protostellar-prestellar cores are found at locations with the highest C18O column densities and their increasing evolutionary age coincides with an increasing 70μm/250μm emission ratio at their location. The evolutionary age of the cores may also follow from the 13CO versus C18O abundance ratio, which decreases with increasing C18O column densities. The original mass has been estimated for nine representative star formation regions and the original mass of the region correlates well with the integrated 70 μm flux density. Similarly, the X13 CO/XC 18 O ratio, which provides the dissociation rate for these regions correlates with the 70 μm/250 μm flux density ratio and reflects the evolutionary age of the star formation activity.

https://www.scopus.com/record/display.uri?eid=2-s2.0-85097343840&origin=resultslist&sort=plf-f
 4 High sensitive NH3 sensor based on electrochemically etched porous silicon Khaniyev, B.A., Sagidolda, Y., Dikhanbayev, K.K., Tileu, A.O., Ibraimov, M.K.

Cogent Engineering

Q2 in Engineering		 In the current study, porous silicon (por-Si) samples were fabricated by electrochemical etching at different times (20 min, 40 min, 60 min). Scanning electron microscope (SEM) images of horizontal cross-sections of the samples showed the formation of pores. The etched samples’ porosity was determined by the gravimetric method and amounted to 59.5%, 72.7%, 83.3%, respectively. Optical characteristics such as Raman spectra and photoluminescence (PL) spectra were obtained. The current-voltage and capacitance-voltage characteristics were also measured to calculate the sensitivity of the samples. The study results show that sample, which is etched for 40 minutes has a maximum response value to ammonia (NH3) gas than others, and the sensitivity is 33.25. The results demonstrated that it is possible to develop a high sensitive sensor device based on por-Si for determining NH3 gas in concentrations below 0.1 ppm at room temperature. 

https://www.scopus.com/record/display.uri?eid=2-s2.0-85090012509&origin=resultslist&sort=plf-f
5  Ammonia observations towards the Aquila Rift cloud complex Tursun, K., Esimbek, J., Henkel, C., Komesh, T., Sailanbek, S.

Astronomy and Astrophysics

Q1 in Physics and Astronomy

 

 We surveyed the Aquila Rift complex including the Serpens South and W 40 regions in the NH3 (1,1) and (2,2) transitions making use of the Nanshan 26-m telescope. Our observations cover an area of ∼ 1.5° × 2.2° (11.4 pc × 16.7 pc). The kinetic temperatures of the dense gas in the Aquila Rift complex obtained from NH3 (2,2)/(1,1) ratios range from 8.9 to 35.0 K with an average of 15.3 ± 6.1 K (errors are standard deviations of the mean). Low gas temperatures are associated with Serpens South ranging from 8.9 to 16.8 K with an average of 12.3 ± 1.7 K, while dense gas in the W 40 region shows higher temperatures ranging from 17.7 to 35.0 K with an average of 25.1 ± 4.9 K. A comparison of kinetic temperatures derived from para-NH3 (2,2)/(1,1) against HiGal dust temperatures indicates that the gas and dust temperatures are in agreement in the low-mass-star formation region of Serpens South. In the high-mass-star formation region W 40, the measured gas kinetic temperatures are higher than those of the dust. The turbulent component of the velocity dispersion of NH3 (1,1) is found to be positively correlated with the gas kinetic temperature, which indicates that the dense gas may be heated by dissipation of turbulent energy. For the fractional total-NH3 (para+ortho) abundance obtained by a comparison with Herschel infrared continuum data representing dust emission, we find values from 0.1 ×10-8 to 2.1 ×10-7 with an average of 6.9 (±4.5) × 10-8. Serpens South also shows a fractional total-NH3 (para+ortho) abundance ranging from 0.2 ×10-8 to 2.1 ×10-7 with an average of 8.6 (±3.8) × 10-8. In W 40, values are lower, between 0.1 and 4.3 ×10-8 with an average of 1.6 (±1.4) × 10-8. Weak velocity gradients demonstrate that the rotational energy is a negligible fraction of the gravitational energy. In W 40, gas and dust temperatures are not strongly dependent on the projected distance to the recently formed massive stars. Overall, the morphology of the mapped region is ring-like, with strong emission at lower and weak emission at higher Galactic longitudes. However, the presence of a physical connection between the two parts remains questionable. 

https://www.scopus.com/record/display.uri?eid=2-s2.0-85096789313&origin=resultslist&sort=plf-f
6  G15.684-0.29: One of the Largest Galactic Infrared Bubbles Showing Strong Evidence of Triggered Star Formation Zhou, J., Zhou, D., Esimbek, J., ...Komesh, T., Tang, X.

Astrophysical Journal

Q1 in Physics and Astronomy		 The bubble G15.684-0.29 has a radius of 15.7 pc. Its large size indicates that it may have enough time to trigger star formation. We identify 39 dense cold clumps around the bubble from the Hi-GAL survey. All of them satisfy the criteria for forming massive stars, and most of them lie in the bubble shell. We identify 19 molecular clumps around the bubble from the 12CO(3-2) survey, all of which are gravitationally bound. We found 9 Class I YSOs, 28 Class II YSOs, and 12 transition disks (TDs) around the bubble. For those young stellar objects (YSOs) located within the bubble boundary, 6 of 7 Class I YSOs lie in the shell, 15 of 22 Class II YSOs lie inside the bubble, and 3 of 5 TDs lie inside the bubble. The dynamical age of G15.684-0.29 in a turbulent medium is ∼4 Myr, which is much greater than the shell fragmentation time, ∼0.82-1.74 Myr. We suggest that triggered star formation may be ongoing in the shell of the bubble, and the collect and collapse model may work here. However, we cannot rule out the possibility that the radiation-driven implosion model may work on the formation of some YSOs. As we expected, the larger bubble has a much longer dynamical age, but we failed to find a clear age gradient for YSOs around the bubble. © 2020. The American Astronomical Society. All rights reserved

https://www.scopus.com/record/display.uri?eid=2-s2.0-85088531809&origin=resultslist&sort=plf-f
 7 Bias voltage-dependent photoinduced current and photoluminescence in organometal perovskite layers on silicon substrates Sekerbayev, K.S., Shabdan, Y., Mikhailova, S.L., Mikhailova, S.L.Taurbayev, T.I., Timoshenko, V.Y.

Physica B: Condensed Matter

Q2 in Electrical and Electronic Engineering

 

 Thin organometal perovskite layers on crystalline silicon substrates under excitation with nanosecond laser pulses were prepared and investigated to reveal an effect of the bias voltage and parameters of the perovskite/silicon structure on photoinduced current and photoluminescence. Numerical simulations of the diffusion, separation and recombination of photoinduced charge carriers in perovskite/silicon structures were carried out to describe both the photoluminescence transient and time-dependent photocurrent at different bias voltage. While the nonradiative surface recombination does not significantly influence the photoluminescence transients for times shorter than 100 ns, the photoinduced current decreases strongly with increasing the surface recombination velocity. The simulation results were compared with experimental ones obtained for organometal perovskite deposited on substrates of optically polished crystalline silicon wafers of p-type conductivity and those covered with silicon nanowires. The obtained results are discussed in view of possible applications of the investigated structures in photovoltaics and light emitting optoelectronics.

https://www.scopus.com/record/display.uri?eid=2-s2.0-85078729645&origin=resultslist&sort=plf-f
8  Influence of dust particles on ionization equilibrium in partially ionized plasmas Davletov, A.E., Kurbanov, F., Mukhametkarimov, Y.S.

Physical Review E

Q1 in Statistics and Probability

 

 A chemical model is proposed for a dusty plasma consisting of electrons, ions, neutrals, and positively charged dust particles all being at thermodynamic equilibrium. An expression is derived for the Helmholtz free energy, which comprises the ideal part, taking into account the charge of dust particles, and the excess part, evaluated in the framework of the self-consistent chemical model [Phys. Rev. E 83, 016405 (2011)PLEEE81539-375510.1103/PhysRevE.83.016405]. The ionization potential depression for a dust-free partially ionized hydrogen is analytically evaluated for weakly and strongly ionized states to consistently account for the presence of charged and neutral components. An ad hoc interpolation of the ionization potential depression, valid across the whole ionization region, is put forward and subsequent solution of the generalized Saha equation is found to be in a perfect agreement with exact calculations. Minimization of the Helmholtz free energy of dusty plasmas provides the number densities of free electrons, free ions, neutrals, and the dust electric charge as well. Based on consideration of weakly and strongly ionized states, a straightforward comparison is made of the ionization equilibrium in a partially ionized plasma with and without dust particles to demonstrate that at thermal equilibrium positively charged dusts are responsible for an increase in the number density of free electrons and a decrease in the number density of free ions. It is analytically proved that nonideality effects result in a growth of the number densities of free electrons and ions by obtaining the so-called electron and proton ionization potential depressions. Electric charge of dust particles is systematically studied as a full plasma component rather than considering a detailed balance of the electron and ion fluxes on the surface of a solitary dust grain

https://www.scopus.com/record/display.uri?eid=2-s2.0-85087171769&origin=resultslist&sort=plf-f
 9 Structure of accretion flows in the nova-like cataclysmic variable RW Tri Subebekova, G., Zharikov, S., Tovmassian, G., Kucáková, H., Khokhlov, S.

Monthly Notices of the Royal Astronomical Society

Q1 in Space and Planetary Science		 We obtained photometric observations of the nova-like (NL) cataclysmic variable RW Tri and gathered all available AAVSO and other data from the literature. We determined the system parameters and found their uncertainties using the code developed by us to model the light curves of binary systems. New time-resolved optical spectroscopic observations of RW Tri were also obtained to study the properties of emission features produced by the system. The usual interpretation of the single-peaked emission lines in NL systems is related to the bi-conical wind from the accretion disc's inner part. However, we found that the Ha emission profile is comprised of two components with different widths. We argue that the narrow component originates from the irradiated surface of the secondary, while the broader component's source is an extended, low-velocity region in the outskirts of the accretion disc, located opposite to the collision point of the accretion stream and the disc. It appears to be a common feature for long-period NL systems-a point we discuss.

https://www.scopus.com/record/display.uri?eid=2-s2.0-85093970755&origin=resultslist&sort=plf-f
 10 Properties of Galactic B[e] Supergiants. V. 3 Pup-Constraining the Orbital Parameters and Modeling the Circumstellar Environments Miroshnichenko, A.S., Danford, S., Zharikov, S.V., Kuratova, A.K., Khokhlov, S.A.

Astrophysical Journal

Q1 in Physics and Astronomy

 

 We report the results of long-term spectroscopic monitoring of the A-type supergiant with the B[e] phenomenon 3 Pup = HD 62623. We confirm earlier findings that it is a binary system. The orbital parameters were derived using cross-correlation of the spectra in a range of 4460-4632 Å, which contains over 30 absorption lines. The orbit was found to be circular with a period of 137.4 ± 0.1 days, radial velocity semiamplitude K 1 = 5.0 ± 0.8 km s-1, systemic radial velocity γ = +26.4 ± 2.0 km s-1, and mass function f(m)=(1.81-0.76+0.97)× 10-3 M o˙. The object may have evolved from a pair with initial masses of ∼6.0 M⊙ and ∼3.6 M o˙ with an initial orbital period of ∼5 days. Based on the fundamental parameters of the A-supergiant (luminosity log L/L o˙ = 4.1 ± 0.1 and effective temperature T eff = 8500 ± 500 K) and evolutionary tracks of mass-transferring binaries, we found current masses of the gainer M 2 = 8.8 ± 0.5 M o˙ and donor M 1 = 0.75 ± 0.25 M o˙. We also modeled the object's IR-excess and derived a dust mass of ∼5 10-5 M o˙ in the optically thin dusty disk. The orbital parameters and properties of the Hα line profile suggest that the circumstellar gaseous disk is predominantly circumbinary. The relatively low mass of the gainer led us to a suggestion that 3 Pup should be excluded from the B[e] supergiant group and moved to the FS CMa group. Overall these results further support our original suggestion that FS CMa objects are binary systems, where an earlier mass transfer caused formation of the circumstellar envelope. 

https://www.scopus.com/record/display.uri?eid=2-s2.0-85088317915&origin=resultslist&sort=plf-f
 11 Measurements of the low-energy neutron and gamma ray accompaniment of extensive air showers in the knee region of primary cosmic ray spectrum Shepetov, A., Chubenko, A., Iskhakov, B., Mukashev, K..Vil’danova, L., Zhukov, V. European Physical Journal Plus Q1 in General Physics and Astronomy Purposeful investigation of radiation fluxes strongly delayed in relation to the main particle front of extensive air shower (EAS) was undertaken at the Tien Shan Mountain Cosmic Ray Station. It was found that the passage of the EAS can be accompanied by the delayed thermal neutrons and by the soft (30–50) keV gamma rays, mostly concentrated within a region of about (5–10) m around the shower axis, where the integral radiation fluence can vary in the limits of (10 - 4- 1) cm- 2 for neutrons, and of (0.1 - 1000) cm- 2 for gamma rays. The dependence of signal multiplicity on the shower size Ne has a power shape both for the neutron and gamma ray components, with a sharp increase of its power index around the value of Ne≈ 10 6, which corresponds to the position of the 3 × 10 15 eV knee in the primary cosmic ray spectrum. The total duration of detectable radiation signal after the EAS passage can be of some tens of milliseconds in the case of neutron component, and up to a few whole seconds for gamma rays. The delayed accompaniment of low-energy radiation particles can be an effective probe to study the interaction of the hadronic component of EAS.

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 12 Improvement of the pseudocapacitive performance of cobalt oxide-based electrodes for electrochemical capacitors Mirzaeian, M., Akhanova, N., Gabdullin, M., Nurbolat, S., Abdullin, K.

Energies

Q1 in Control and Optimization

 

 Cobalt oxide nanopowders are synthesized by the pyrolysis of aerosol particles of water solution of cobalt acetate. Cobalt nanopowder is obtained by subsequent reduction of obtained cobalt oxide by annealing under a hydrogen atmosphere. The average crystallite size of the synthesized porous particles ranged from 7 to 30 nm, depending on the synthesis temperature. The electrochemical characteristics of electrodes based on synthesized cobalt oxide and reduced cobalt oxide are investigated in an electrochemical cell using a 3.5 M KOH solution as the electrolyte. The results of electrochemical measurements show that the electrode based on reduced cobalt oxide (Re-Co3O4) exhibits significantly higher capacity, and lower Faradaic charge–transfer and ion diffusion resistances when compared to the electrodes based on the initial cobalt oxide Co3O4. This observed effect is mainly due to a wide range of reversible redox transitions such as Co(II) ↔ Co(III) and Co(III) ↔ Co(IV) associated with different cobalt oxide/hydroxide species formed on the surface of metal particles during the cell operation; the small thickness of the oxide/hydroxide layer providing a high reaction rate, and also the presence of a metal skeleton leading to a low series resistance of the electrode.

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13 Designing of WO3@Co3O4 Heterostructures to Enhance Photoelectrochemical Performances Markhabayeva, A.A., Moniruddin, M., Dupre, R., Abdullin, K.A., Nuraje, N. Journal of Physical Chemistry A Q2 in Physical and Theoretical Chemistry Heterostructured photocatalysts are superior to single photocatalysts because they offer better charge separation and broaden light harnessing abilities. Although WO3 is considered an oxygen-evolving photocatalyst with decent stability and proper band gap, its lower photocatalytic efficiency is ascribed to high charge recombination. In this research, a WO3@Co3O4 heterostructure reduced the recombination of photocatalytic charges and extended light absorption abilities, resulting in improved photocatalytic activity. The presence of Co3O4 nanoparticles improved light absorption and charge transfer of tungsten oxide films for photoelectrochemical reactions. For photoelectrochemical water oxidation, WO3@Co3O4 nanostructures generated a photocurrent 20 times higher than that of pure WO3. Both electrodeposition and sol gel techniques were utilized to synthesize the WO3@Co3O4 photoelectrode. Scanning electron microscopy and X-ray diffraction were used to characterize the formation of the above photocatalyst. A photocurrent study was done to investigate the charge separation mechanism to explain the enhanced photocatalytic activity. 

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