East European Journal of Physics https://periodicals.karazin.ua/eejp <p>EEJP is an international peer-reviewed journal devoted to experimental and theoretical research on nuclear physics, cosmic rays and particles, high-energy physics, solid-state physics, plasma physics and controlled thermonuclear fusion, physics of charged particle beams, plasma electronics, radiation materials science, physics of thin films, condensed matter physics, functional materials and coatings, technical thermal physics and industrial power, medical physics and physical technologies in an interdisciplinary context.</p> <p>EEJP registered by the order of Ministry of Education and Science of Ukraine <strong>No. 1643 of 28.12.2019</strong>, and included in the list of scientific professional Editions of Ukraine (<strong>category “A”, specialty: 104, 105</strong>), in which results of dissertations for obtaining Ph.D. and Dr. Sci. degrees in physical and mathematical sciences can be published.</p> <p>The Journal is a part of the <strong>Web of Science Core Collection (ESCI)&nbsp;</strong>scientometric platform and indexed by&nbsp;<strong>SCOPUS</strong>.</p> <p><a title="SCImago Journal &amp; Country Rank" href="https://www.scimagojr.com/journalsearch.php?q=21101018929&amp;tip=sid&amp;exact=no"><img src="https://www.scimagojr.com/journal_img.php?id=21101018929" alt="SCImago Journal &amp; Country Rank" border="0"></a>&nbsp;</p> <p>&nbsp;</p> en-US <p>Authors who publish with this journal agree to the following terms:<br><br></p> <ol type="a"> <ul> <li class="show">Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a&nbsp;<a href="http://creativecommons.org/licenses/by/4.0/" target="_new">Creative Commons Attribution License</a> that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.</li> </ul> </ol> <ol type="a"> <ul> <li class="show">Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.</li> </ul> </ol> <ol type="a"> <ul> <li class="show">Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See&nbsp;<a href="http://opcit.eprints.org/oacitation-biblio.html" target="_new">The Effect of Open Access</a>).</li> </ul> </ol> eejp@karazin.ua (Serhii Hirnyk) eejp@karazin.ua (Serhii Hirnyk) Fri, 02 Sep 2022 09:35:01 +0000 OJS http://blogs.law.harvard.edu/tech/rss 60 On the Mechanisms of Formation of Density Cavities under Instability of Intense Langmuir Oscillations in a Plasma https://periodicals.karazin.ua/eejp/article/view/18814 <p>The paper considers the instability of intense Langmuir oscillations in nonisothermal (Zakharov's model) and cold (Silin's model) 1D plasma. The main attention is paid to the formation of plasma density caverns in the hydrodynamic and hybrid (electrons are described hydrodynamically, ions are described by model particles) representations. In the hydrodynamic representation, with a small number of spectrum modes, large-scale plasma density caverns are observed, which rapidly deepen. This process is supported by the appearance of small-scale perturbations, and phase synchronization of the Langmuir waves of the instability spectrum is observed. This phase synchronization of the spectrum modes is quite capable of fulfilling the role that was previously proposed to be given exclusively to the effect of extrusion of particles from the cavity by the field. In hybrid models, in the region of consideration, ions are described by model particles, the number of which in the one-dimensional case 10<sup>4</sup>-5*10<sup>5</sup> (which in the three-dimensional case corresponds to the number of particles 10<sup>12</sup>-10<sup>14</sup>). The initial spectrum of perturbations is very wide and rather intense, which leads to an explosive growth of perturbations in the Zakharov model and a rapid development of instability in the Silin model. In this case, in the developed instability regime, the formation of many small-scale plasma density caverns is observed. It is the presence of this small-scale modulation due to the Fermi effect that quickly forms the normal distribution of ions over velocities. In this case, the effect of particle heating due to Landau damping loses its primacy. It is shown that the caverns practically do not change their position; phase changes for the spectral components of the plasma density were not observed. Only individual small-scale caverns demonstrate dynamics similar to the development of caverns in the hydrodynamic representation.</p> Volodymyr Kuklin Copyright (c) 2022 Volodymyr M. Kuklin http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18814 Fri, 02 Sep 2022 00:00:00 +0000 Superradiation of Mobile Oscillators https://periodicals.karazin.ua/eejp/article/view/18815 <p>The paper considers the development of the process of superradiance of radiating oscillators interacting with each other by means of an electromagnetic field. The interaction of oscillators occurs both with the nearest neighbors and with all other oscillators in the system. In this case, the possibility of longitudinal motion of oscillators along the system, due to the action of the Lorentz force, is taken into account. It is shown that, regardless of the motion of the oscillators, for example, due to their different masses, the maximum attainable amplitude of the generation field changes little. However, the radiation efficiency depends on how this field is distributed in the longitudinal direction. In the case of a shift of the field maximum towards the ends of the system, the radiation efficiency can noticeably increase. In addition, the direction of the phase velocity of the external initiating field is important, which accelerates the process of phase synchronization of the oscillators. This can also affect the ejection of particles outside the initial region, and here the total number of ejected particles and their speed turn out to be important. It is discussed how the density of oscillators and the size of the region occupied by oscillators will change.</p> Eugen Poklonskiy, Stanislav Totkal Copyright (c) 2022 Eugen V. Poklonskiy, Stanislav O. Totkal http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18815 Fri, 02 Sep 2022 00:00:00 +0000 7.379 % Power Conversion Efficiency of a Numerically Simulated Solid-State Dye-Sensitized Solar Cell with Copper (I) Thiocyanate as a Hole Conductor https://periodicals.karazin.ua/eejp/article/view/18816 <p>Sourcing for an alternative to the liquid electrolyte in dye-sensitized solar cells (DSSCs) have been the subject of interest in the photovoltaic horizon. Herein, we reported by means of simulation, the performance of dye-sensitized solar cell by replacing the liquid electrolyte with a copper (I) thiocyanate (CuSCN) hole conductor. The study was carried out using Solar Capacitance Simulation Software (SCAPS) which is based on poisson and continuity equations. The simulation was done based on an n-i-p proposed architecture of FTO/TiO<sub>2</sub>/N719/CuSCN/Pt. The result of the initial device gave a Power Conversion Efficiency (PCE), Fill Factor (FF), Short Circuit Current Density (Jsc) and Open Circuit Voltage (Voc) of 5.71 %, 78.32 %, 6.23 mAcm<sup>-2</sup>, and 1.17&nbsp;V. After optimizing input parameters to obtain 1×10<sup>9</sup> cm<sup>-2</sup> for CuSCN/N719 interface defect density, 280 K for temperature, 1.0 μm for N719 dye thickness, 0.4&nbsp;μm for TiO<sub>2</sub> thickness, Pt for metal back contact, and 0.2 μm for CuSCN thickness, the overall device performance of 7.379 % for PCE, 77.983&nbsp;% for FF, 7.185&nbsp;mAcm<sup>-2</sup> for Jsc and 1.317 V for Voc were obtained. When compared with the initial device, the optimized results showed an enhanced performance of ~ 1.29 times, 1.15 times, and 1.13 times in PCE, Jsc, and Voc over the initial device. The results obtained are encouraging and the findings will serve as a baseline to researchers involved in the fabrication of novel high-performance solid-state DSSCs to realize its appealing nature for industry scalability.</p> Eli Danladi, Muhammad Kashif, Thomas Daniel, Christopher Achem, Matthew Alpha, Michael Gyan Copyright (c) 2022 Eli Danladi, Muhammad Kashif, Thomas O. Daniel, Christopher U. Achem, Matthew Alpha, Michael Gyan http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18816 Fri, 02 Sep 2022 00:00:00 +0000 The Study of Electronic States of Ni and ScI Molecules with Screened Kratzer Potential https://periodicals.karazin.ua/eejp/article/view/18817 <p>In this study, the analytical solutions of the Schrödinger equation with the screened Kratzer potential model is solved using the well-known Nikiforov-Uvarov method. The energy spectrum and the normalized wave function with the Greene-Aldrich approximation to the centrifugal term are obtained. The energy spectrum is used to generate eigenvalues for X<sup>3</sup>Σ<sup>-</sup> state of NI and X<sup>1</sup>Σ<sup>+</sup>&nbsp;state of ScI molecules respectively. The calculated results agree excellently with the experimental data. This research finds application in chemistry, industry, molecular physics and studies on magnetocaloric effect for several molecules. Our findings also demonstrate that the approximation scheme is well suited for this potential.</p> Etido Inyang, Effiong Obisung Copyright (c) 2022 Etido P. Inyang, Effiong O. Obisung http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18817 Fri, 02 Sep 2022 00:00:00 +0000 Entangled Coherent States in Teleportation https://periodicals.karazin.ua/eejp/article/view/18554 <p>In the present paper, we will review the methods to produce superposition of entangled coherent state using polarizing beam splitter and Kerr non linearity. These coherent states have many attractive features and can be used in various schemes. Entanglement, refers to the superposition of a multiparticle system and explains a new type of correlations between any two subsystems of the quantum system, which is not existing in the classical physics. The present paper deals with the use of these states in quantum teleportation, entanglement diversion and entanglement swapping schemes. Entanglement diversion and entanglement-swapping refers to a scheme which may entangle those particles which had never interacted before. In the swapping scheme, two pairs of entangled state are taken. One particle from each pair is subjected to a Bell-state-measurement. This would result in projection of the other two outgoing particles in an entangled pair. Quantum Teleportation of two mode and three modes states is also studied with perfect fidelity. Minimum assured fidelity which is defined as the minimum of the fidelity for any unknown quantum information of the states is also discussed. It is also shown how the success rate of teleportation of a superposition of odd and even coherent states can be increased from 50% to almost 100%. The scheme suggested by van Enk and Hirota was modified by Prakash, Chandra, Prakash and Shivani in 2007. We find that an almost teleportation, diversion and swapping is possible by simply separating vacuum state from the even state. The present paper also deals with study of effect of decoherence and noise on these states and the effect of noise on fidelity and minimum assured fidelity. It is also discussed that these schemes can also be applied to the process of entanglement diversion and entanglement swapping.</p> <p>.</p> Shivani A. Kumar, Shefali Kanwar, Pramila Shukla Copyright (c) 2022 Shivani A. Kumar, Shefali Kanwar, Pramila Shukla http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18554 Fri, 02 Sep 2022 00:00:00 +0000 Pressure of Electromagnetic Radiation on a Thin Linear Vibrator in a Waveguide https://periodicals.karazin.ua/eejp/article/view/18818 <p>The problem of electromagnetic wave pressure on a thin conductive vibrator located in a rectangular waveguide is solved. Wave H<sub>10</sub> falls on the vibrator. The vibrator is located perpendicular to the wide wall of the waveguide. The current in the vibrator arising under the action of the electric field of the wave is calculated. The current distribution along the vibrator is almost uniform. The current in the microwave range depends little on the vibrator conductivity. Two components of the magnetic field - longitudinal and transverse exist in the H<sub>10</sub> wave. When these components interact with the current in the vibrator, forces arise, acting on the vibrator across the waveguide and along it. The magnitude of the longitudinal force is greatest when the vibrator is located in the middle of a wide wall. It is almost 2 times greater than the force acting on the vibrator in free space at the same average radiation intensity, When the vibrator length is close to half the radiation wavelength, the force is maximum. The transverse force is determined by the interaction of the current in the vibrator with the longitudinal component of the magnetic field in the waveguide. It is maximum when the vibrator is located at the distance of ¼ of the length of the wide wall from its middle. If the length of the vibrator is less than half the wavelength of the radiation, the force is directed towards the axis of the waveguide, otherwise - in the opposite direction. The possibility of using microwave radiation pressure to create micromachines and to control the position of the vibrator in space has been evaluated. This requires a radiation power of several watts.</p> Mykola Kokodii, Victor Katrich, Sergey Berdnik, Mykhail Nesterenko, Vyacheslav Maslov, Ivan Priz Copyright (c) 2022 Mykola G. Kokodii, Victor O. Katrich, Sergey L. Berdnik, Mykhail V. Nesterenko, Vyacheslav O. Maslov, Ivan O. Priz http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18818 Fri, 02 Sep 2022 00:00:00 +0000 Comprehensive Assessment of Biological Substrates of Professional Sick Person Group by Chemometric and Nuclear Physical Methods https://periodicals.karazin.ua/eejp/article/view/18819 <p>The article deals with the influence of negative factors of working conditions on the health status of NSC KIPT personnel when working with beryllium. Beryllium and its compounds render a general toxic, allergenic and carcinogenic effect on the organism. The high biological activity and toxicity of Be is due to its chemical activity and penetrating ability. The chronic professional disease such as berylliosis occurs as a result of prolonged systematic exposure on the organism of adverse factors. Elemental analysis of biosubstrates provides important information, that in combination with symptoms and other laboratory parameters, can help in the early diagnostics of physiological violations associated with metabolic disorders and exposure of toxic elements. The blood and hair samples were taken from 28 people, among which 5 patients were selected as a control group, and a group of 23 people were former employees of the beryllium production. The content of chemical elements in the biological substrates (blood and hair) of employees was determined by nuclear-physical methods. An elemental analysis was performed on the analytical nuclear physics complex appliance “Sokol”. The methods based on registration of characteristic X-ray radiation of atoms and g-radiation of nuclei excited by accelerated protons is used. After measurements, data arrays were obtained on the content of 14 chemical elements (N, Na, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Sr, Pb) in blood and hair. The processing of data arrays was carried out using the principal component method which is related to chemometrics technologies. As a result of the work, an analytical program was composed in MATLAB codes which were used to determine the content of elements in biosubstrates that are most sensitive to changes in external conditions. This made it possible to identify certain groups of patients who have different health state indicators, as well as to see the similarities or differences between patients depending on the different concentrations of chemical elements in the blood or hair.</p> Maryna Коzhevnikova, Volodymyr Levenets, Oleksandr Omelnyk, Andriy Shchur Copyright (c) 2022 Maryna F. Коzhevnikova, Volodymyr V. Levenets, Oleksandr P. Omelnyk, Andriy O. Shchur http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18819 Fri, 02 Sep 2022 00:00:00 +0000 Manufacturing Features and Characteristics of Uranium Dioxide Pellets for Subcritical Assembly Fuel Rods https://periodicals.karazin.ua/eejp/article/view/18761 <p>The influence of technological processes and manufacturing of uranium dioxide fuel pellets for fuel elements for experimental fuel assembly (FA-X) which was designed as an alternative fuel for the nuclear research installation (NRI) "Neutron Source Controlled by Electron Accelerator" were investigated. Unlike standard production processes of UO<sub>2</sub> pellets, the special feature fabrication process of this nuclear fuel type is production of uranium dioxide powder with enrichment of 4.4 %wt. of <sup>235</sup>U achieved by mixing of two batches of powders with different uranium contents: 0.4 %wt. <sup>235</sup>U and 19.7%wt. <sup>235</sup>U, as well as ensuring the required tolerance of fuel pellets without the use of machining operations. A set of design and process documentation were developed in the R&amp;D Center at NSC KIPT. Experimental stack of fuel pellets, fuel elements and a pilot fuel assembly FA-X were fabricated and designed to be compatible and interchangeable with VVR-M2 fuel assembly adopted as a standard assembly for the first fuel loading at the "Neutron Source Driven by an Electron Accelerator" FA. As opposition to the variant of VVR-M2 fuel assembly which consisted of three fuel rods of tubular shape with dispersion composition UO<sub>2</sub>‑Al, FA-X accommodates six fuel rods of pin-type with UO<sub>2</sub> pellet which located in the zirconium cladding (E110) as the closest analogue of fuel rods of VVER-1000 power reactor. Inside cladding locate a 500 mm high fuel stack which is secured against displacement by a spacer. In the basic variant of FA-X the fuel pellets are made of UO<sub>2</sub> with <sup>235</sup>U enrichment near 4.4 %wt.</p> Igor Chernov, Аnton Kushtym, Volodymyr Tatarinov, Dmytro Kutniy Copyright (c) 2022 Igor Chernov, Аnton Kushtym, Volodymyr Tatarinov http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18761 Fri, 02 Sep 2022 00:00:00 +0000 Enhanced Performance of CuIn1-xGxSe2 Solar Cell Through Optimization of Absorber and Buffer Layer Properties Using SCAPS-1D https://periodicals.karazin.ua/eejp/article/view/18820 <p>This study is a follow up to our previously published article on “Numerical Simulation of Copper Indium Gallium Diselenide Solar Cells Using One Dimensional SCAPS Software”. Five more parameters were optimized which are: absorber band gap, absorber electron affinity, buffer layer band gap, buffer layer electron affinity and working temperature using the same simulation tool initially used. When the absorber bandgap was varied between 0.8 eV and 1.6 eV, the efficiency of the solar cell increases until it reached its peak at 27.81%. This occurred at absorber bandgap of 1.4 eV. Other photovoltaic parameters at this optimum value are: V<sub>oc </sub>of 1.00&nbsp;V, J<sub>sc </sub>of 31.99 mA/cm<sup>2 </sup>and FF of 87.47 %. On varying the absorber electron affinity from 4.20 eV through 4.55 eV, we obtained an optimum value of 4.45 eV at V<sub>oc </sub>of 0.82 V, J<sub>sc </sub>of 37.96 mA/cm<sup>2</sup>, FF of 84.99 % and an efficiency of 26.36%. The optimization of buffer bandgap resulted in an optimal value of 3.0 eV, when the buffer bandgap was varied between 1.6 eV and 3.2 eV. The photovoltaic parameters at this optimal value are: V<sub>oc </sub>of 0.80 V, J<sub>sc </sub>of 37.96 mA/cm<sup>2</sup>, FF of 85.22 % and an efficiency of 25.86%. The effect of buffer electron affinity was studied by varying its value between 4.00 eV and 4.40 eV and its best value was found to be 4.05&nbsp;eV at photovoltaic parameters with a V<sub>oc </sub>of 0.82 V, J<sub>sc </sub>of 37.96 mA/cm<sup>2</sup>, FF of 84.98 % and an efficiency of 26.36 %. These optimized values in all parameters were used to simulate a solar cell which resulted to device with performances: V<sub>oc </sub>of 1.11 V, J<sub>sc </sub>of 31.50 mA/cm<sup>2</sup>, FF of 88.91 % and an efficiency of 31.11 %. On varying the working temperature on the optimized solar cell, the optimized device with its best performance at 270 K with Photovoltaic (PV) values of V<sub>oc </sub>of 1.15 V, J<sub>sc </sub>of 31.55 mA/cm<sup>2</sup>, FF of 88.64 % and an efficiency of 32.18%. The results obtained were encouraging and can serve as a guide to those involved in practical development of solar cells.</p> Godwin Ibeh, Celine Lawani, Jayeola Emmanuel, Peter Oyedare, Eli Danladi, Olumide Ige Copyright (c) 2022 Godwin J. Ibeh, Celine O. Lawani, Jayeola O. Emmanuel, Peter O. Oyedare, Eli Danladi, Olumide O. Ige http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18820 Fri, 02 Sep 2022 00:00:00 +0000 Slow Surface Eigenmodes Directed by the Mu-Negative Metamaterial Slab https://periodicals.karazin.ua/eejp/article/view/18821 <p>The paper presents the results of the study of slow surface electromagnetic waves directed along the flat mu-negative metamaterial slab surrounded by ordinary dielectric material. It is considered the case of isotropic and homogeneous metamaterial without losses. This metamaterial possesses the positive permittivity and the negative permeability over a definite frequency band. It is found that two surface modes of TE polarization can propagate along such waveguide structure. The dispersion properties, the spatial distribution of the electromagnetic field, as well as the phase and group velocities of these slow modes are studied. The first mode is a conventional forward wave, and has a lower frequency and lower phase velocity than the second mode. The second mode may have zero group velocity at a certain frequency. Characteristics of these surface modes for different values of the mu-negative slab parameters have been studied. The studied surface electromagnetic waves can be used for practical applications as in laboratory experiments, as in various technologies.</p> Viktor Galaydych, Oleksandr Sporov, Volodymyr Olefir, Mykola Azarenkov Copyright (c) 2022 Viktor K. Galaydych, Oleksandr E. Sporov, Volodymyr P. Olefir, Mykola O. Azarenkov http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18821 Fri, 02 Sep 2022 00:00:00 +0000 Effect of Na Doping on Some Physical Properties of Chemically Sprayed CZTS Thin Films https://periodicals.karazin.ua/eejp/article/view/18763 <p>In this work, sodium-doped copper zinc tin sulfide (CZTS) thin films are prepared by depositing them on glass substrates at temperature of (400±10) °C and thickness of (350±10) nm using Chemical Spray Pyrolysis (CSP) technique. 0.02 M of copper chloride dihydrate (CuCl<sub>2</sub>.2H<sub>2</sub>O), 0.01 M of zinc chloride (ZnCl<sub>2</sub>), 0.01 M of tin chloride dihydrate (SnCl<sub>2</sub>.2H<sub>2</sub>O), and 0.16&nbsp;M of thiourea (SC(NH<sub>2</sub>)<sub>2</sub>) were used as sources of copper, zinc, tin, and sulphur ions respectively. Sodium chloride (NaCl) at different volumetric ratios of (1, 3, 5, 7 and 9) % was used as a dopant source. The solution is sprayed on glass substrates. XRD diffraction, Raman spectroscopy, FESEM, UV-Vis-NIR, and Hall effect techniques were used to investigate the structural, optical, and electrical properties of the produced films. The XRD diffraction results revealed that all films are polycrystalline, with a tetragonal structure and a preferential orientation along the (112) plane. The crystallite size of all films was estimated using Scherrer's method, and it was found that the crystallite size decreases as the doping ratio increases. The FESEM results revealed the existence of cauliflower-shaped nanoparticles. The optical energy band gap was demonstrated to have a value ranging from 1.6 to 1.51&nbsp;eV with a high absorption coefficient (α ≥10<sup>4</sup> cm<sup>-1</sup>) in the visible region of the spectrum. Hall measurements showed that the conductivity of CZTS thin films with various Na doping ratios have p-type electrical conductivity, and it increases as the Na doping ratio increases.</p> Noura Mahdi, Nabeel Bakr Copyright (c) https://periodicals.karazin.ua/eejp/article/view/18763 Fri, 02 Sep 2022 00:00:00 +0000 Structural, Electrical and Optical Properties of Graphite Films are Drawn with Pencils of Different Hardness https://periodicals.karazin.ua/eejp/article/view/18822 <p>The paper presents the results of studying the structural, optical and electrical properties of thin films of graphite depending on the hardness of the rods (2H, H, HB, B and 2B) obtained by the "Pencil-on-semiconductor" method. Such studies are of great importance for the further development of highly efficient devices based on heterojunctions for electronics and optoelectronics. Typical images of the surface formed by reflected electrons (BSE) were obtained using a scanning electron microscope and shown at three magnifications (100x, 500x and 1000x). Since the cores of the studied pencils consist of mixtures of clay and graphite, a more detailed analysis of the elements that make up the cores was conducted. EDS analysis showed that the main components of the studied rods are purified graphite powder, as well as O, Al and Si, which are part of kaolin whose formula is H<sub>4</sub>Al<sub>2</sub>Si<sub>2</sub>O<sub>9</sub>, or Al<sub>2</sub>O<sub>3</sub> • 2SiO<sub>2</sub> • 2H<sub>2</sub>O - the main component of ordinary clay. The elemental composition of the microvolume of the studied samples was also determined. Regardless of the error that occurs when determining the composition of C and O (~ 12%), it can be argued that there is still a regularity between the graphite content and the hardness of the pencil. That is, the higher the graphite content, the softer the rod. The thickness of the graphite films was measured using the MII-4 interferometer according to the standard method. The average thickness of all investigated films was ~ 150 nm since the thickness of the films obtained by this method is mainly determined by the roughness of the surface of the salt substrate. &nbsp;Drawn graphite films have a higher resistivity than bulk samples (pencil rods) from which they were made. The resistance of the films increases with an increase in the hardness of pencils, due to an increase in the number of clay impurities in graphite, which is a dielectric. It was found that an increase in stick hardness leads to an increase in transmission.</p> Serhii Kuryshchuk, Taras Kovalyuk, Ivan Koziarskyi, Mykhailo Solovan Copyright (c) 2022 Serhii I. Kuryshchuk, Taras T. Kovalyuk, Ivan P. Koziarskyi, Mykhailo M. Solovan http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18822 Fri, 02 Sep 2022 00:00:00 +0000 Bianchi Type V Tsallis Holographic Dark Energy Model with Hybrid Expansion Law https://periodicals.karazin.ua/eejp/article/view/18825 <p>A number of recent cosmological observations have provided increasing evidence that currently the universe is undergoing a phase of accelerated expansion, the root cause of which is supposed to be due to an exotic component of the universe with large negative pressure, dubbed dark energy. Out of the various candidates of dark energy proposed in the literature, the holographic dark energy emerged from the Holographic Principle is drawing much attention in the research field. In this paper, we investigate a spatially homogeneous and anisotropic Bianchi Type V space-time filled with non-interacting Tsallis holographic dark energy (THDE) with Hubble horizon as the IR cutoff and pressureless cold dark matter within the framework of General Relativity. Exact solutions of the Einstein field equations are obtained by considering the average scale factor &nbsp;to be a combination of a power law and an exponential law, the so called hybrid expansion law first proposed by Akarsu <em>et al</em>. (2014). We study the cosmological dynamics of various models for different values of the non-additive parameter &nbsp;that appeared in the Tsallis entropy and that for &nbsp;that appeared in the exponential function of the hybrid expansion law. We find that our model exhibits present cosmological scenario.</p> Manash Das, Chandra Mahanta Copyright (c) 2022 Manash Pratim Das, Chandra Rekha Mahanta http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18825 Fri, 02 Sep 2022 00:00:00 +0000 Non-Relativistic Study of Mass Spectra, and Thermal Properties of a Quarkonium System with Eckart-Hellmann Potential https://periodicals.karazin.ua/eejp/article/view/18823 <p>In this present study, we model Eckart-Hellmann Potential (EHP) to interact in a quark-antiquark system. The solutions of the Schrödinger equation are obtained with EHP using the Nikiforov-Uvarov method. The energy equation and normalized wave function were obtained. The masses of the heavy mesons such as charmonium (cc<sup>-</sup>) and bottomonium (bb<sup>-</sup>) for different quantum numbers were predicted using the energy equation. Also, the partition function was calculated from the energy equation, thereafter other thermal properties such as mean energy, free energy, entropy, and specific heat capacity were obtained. The results obtained showed an improvement when compared with the work of other researchers and excellently agreed with experimental data.</p> Etido Inyang, Effiong Obisung, Eddy William, Ituen Okon Copyright (c) 2022 Etido P. Inyang, Effiong O. Obisung, Eddy S. William, Ituen B. Okon http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18823 Fri, 02 Sep 2022 00:00:00 +0000 Multiple Docking of Fluorescent Dyes to Fibrillar Insulin https://periodicals.karazin.ua/eejp/article/view/18824 <p>The co-localization of the donor and acceptor fluorophores capable of transferring the energy by the Fӧrster mechanism, on the molecular scaffold of amyloid fibrils offers new opportunities not only for refinement of the amyloid detection and structural analysis, but also for designing photonic nanodevices on their basis. The assembly of these systems involves the non-covalent dye-protein interactions which can hardly be characterized in terms of a precise dye location within the fibril structure that is required for fabricating the FRET-based light harvesting systems or photonic nanowires. In view of this, the dye-fibril binding process deserves a detailed <em>in silico</em> study. In the previous molecular docking studies of the FRET donors and acceptors interacting with the insulin model fibrils we considered only one ligand during the simulation procedure. However, the real situation is much more complicated, when the multiple ligands can compete for the same binding site, a direct complexation between the dyes on the fibril scaffold can take place, the spatial distribution of the bound fluorophores can be unfavorable for the energy transfer, etc. In addition, the mutual orientation of the donor and acceptor molecules essentially contribute to the efficiency of the Förster resonance energy transfer (FRET) in the investigated systems. The present study was undertaken to gain molecular docking insight into the binding of the donor (Thioflavin T) and acceptor (Congo Red or a phosphonium dye TDV) fluorophores to the insulin amyloid fibrils using the multiple docking approach. The employed PatcDock and SwissDock webserves provided evidence for the preferable association of all dyes with the fibril grooves. The protein-ligand interaction profiler (PLIP) was employed for analyzing the (InsF + ThT +CR) and (InsF + ThT&nbsp;+ TDV) systems. The revealed binding modes and the types of the dye-fibril interactions may be of importance for a more detailed analysis of the FRET process in amyloid systems and may serve as a background for further<em> in silico</em> studies of the cascade FRET on the amyloid fibril scaffold.</p> Uliana Tarabara, Olga Zhytniakivska, Kateryna Vus, Valeriya Trusova, Galyna Gorbenko Copyright (c) 2022 Uliana Tarabara, Olga Zhytniakivska, Kateryna Vus, Valeriya Trusova, Galyna Gorbenko http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18824 Fri, 02 Sep 2022 00:00:00 +0000 Calculation of the Absorbed Dose by a Borosilicate Glass Matrix and its Simulated Irradiation https://periodicals.karazin.ua/eejp/article/view/18829 <p>The state of liquid radioactive wastes (LRW) management at Ukrainian Nuclear Power Plants (NPPs) is characterized by the lack of a completed technological cycle from processing to obtaining the final product suitable for further long-term storage or disposal. As a result, the storage tanks for bottoms residue (BR) are 65-75% full (Zaporozhye and South-Ukrainian NPPs), and the resource for placing molten salt at Zaporizhzhya NPP (92.7%) is close to exhaustion [1]. Therefore, the development of technologies and materials for NPP LRW solidification is an urgent need and aims to ensure the processing of LRW to a solid state that will meet the acceptance criteria for disposal in centralized storage facilities. One of the effective methods of LRW solidification is their vitrification. The main advantage of vitrification is that during the vitrification process the volume of waste is reduced by several times and this saves expensive storage space [2, 3]. The purpose of this work is to calculate the absorbed dose that borosilicate glass matrices with included bottoms residue will accumulate over 300 years of storage, and to study the effect of simulated X-ray irradiation on their physical and mechanical properties.</p> Volodymyr Morgunov, Serhii Sayenko, Volodymyr Shkuropatenko, Yevhenii Svitlychnyi, Olena Bereznyak, Serhii Lytovchenko, Volodymyr Chyshkala Copyright (c) 2022 Volodymyr Morgunov, Serhii Sayenko, Volodymyr Shkuropatenko, Yevhenii Svitlychnyi, Olena Bereznyak, Serhii Lytovchenko, Volodymyr Chyshkala http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18829 Fri, 02 Sep 2022 00:00:00 +0000 Effects of Gravitational Field of a Topological Defect on Statistical Properties of Heavy Quark-Antiquark Systems https://periodicals.karazin.ua/eejp/article/view/18838 <p>In this paper, we determine eigen energies, eigenfunctions and statistical properties of non-relativistic heavy quarkonia interacting with the extended Cornel potential within a space-time generated by a cosmic-string. We extend the Cornel potential by adding the inverse square potential plus the quadratic potential. We have calculated the energy eigenvalues and the corresponding eigenstates using the Extended Nikiforov-Uvarov (ENU) method. Then, based on the equation of energy spectra, the thermodynamic properties like partition function, entropy, free energy, mean energy and specific heat capacity are calculated within the space-time of a cosmic-string. In the next step, we investigate the influence of the cosmic-string parameter on quantum states of heavy quarkonia and their statistical properties.</p> André Likéné, Ali Zarma, Dieudonné Ongodo, Jean Marie Ema'a Ema'a, Patrice Abiama, Germain Ben-Bolie Copyright (c) 2022 André Aimé Atangana Likéné, Ali Zarma, Dieudonné Nga Ongodo, Jean Marie Ema'a Ema'a, Patrice Ele Abiama http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18838 Fri, 02 Sep 2022 00:00:00 +0000 Molecular Docking of Monomethine Cyanine Dyes to Lysozyme Amyloid Fibrils https://periodicals.karazin.ua/eejp/article/view/18846 <p>Protein aggregation into highly ordered supramolecular aggregates is the hallmark of many degenerative diseases including the neurological disorders (Parkinson’s, Alzheimer’s, and Huntington’s diseases), type II diabetes, systemic amyloidosis, spongiform encephalopathies, etc. One of the simplest and effective methods for the identification and characterization of amyloid fibrils <em>in vitro</em> and the visualization of amyloid inclusions <em>in vivo </em>is based on the use of probes sensitive to the beta-pleated motifs. In the attempt to design new amyloid-sensing dyes or to optimization the existing molecules, it is crucial to have the sufficient knowledge of the molecular and atomic levels interactions in the binding sites. Among the especially useful methods available to provide the atomic-level insights into the mechanisms of various types of biomolecular interactions is molecular docking technique. In the present study, the molecular docking tool has been employed to investigate the interactions between the monomethine cyanine dyes and the lysozyme amyloid fibrils constructed from the K-peptide of lysozyme, GILQINSRW (residues 54–62 of the wild-type protein). Using the AutoDOCK and the protein-ligand interaction profiler PLIP it was found: i) monomethines interact with the fibril surface (with the aromatic residues on the top of β-sheet or with the edges of the β-sheet); ii) the dye binding is governed by the hydrophobic interactions, salt bridges and the hydrogen bonds between the aliphatic substituents on the nitrogen atom of benzothiazole part of dye molecules and the lysozyme amyloid fibril; iii) the variations in the cyanine structure and in the lysozyme amiloid twisting didn’t insert significant effect on the binding mode of cyanines.</p> Olga Zhytniakivska, Uliana Tarabara, Atanas Kurutos, Kateryna Vus, Valeriya Trusova, Galyna Gorbenko Copyright (c) 2022 Olga Zhytniakivska, Uliana Tarabara, Atanas Kurutos, Kateryna Vus, Valeriya Trusova, Galyna Gorbenko http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18846 Fri, 02 Sep 2022 00:00:00 +0000 Sample Preparation for the Effective Accumulation and Detection of the Beta-Active Rn-222 Decay Products https://periodicals.karazin.ua/eejp/article/view/18847 <p>The sample preparation method and the results of experimental measurements of the concentration of beta-radioactive aerosols (the decay products of Radon-222 in the air) are presented. The experimental equipment includes an electrostatic aerosol collector and a time spectrometer based on the PMT with a plastic scintillator and Wilkinson’s ADC. The&nbsp;accumulation of aerosols on the foil lasted for about 12 hours. The activity of accumulated aerosols was measured in the time interval of 0 to 300 minutes. The use of the spectrometer in the time analyzer mode, the proposed aerosol accumulator, and the method of processing the accumulated spectrum makes it possible to increase the sensitivity of the radiometer in&nbsp;comparison with the collection method based on air filters. Applying the time‑spectrum development procedure to&nbsp;the&nbsp;constituent components makes it possible to reliably establish the connection of aerosols registered in the room with β‑active decay products of radon-222: Po-218, Pb-214, Bi-214.</p> Gennadiy Onyshchenko, Ivan Yakymenko, Oleksandr Shchus', Anatoliy Lokha Copyright (c) 2022 Gennadiy Onyshchenko, Ivan Yakymenko, Oleksandr Shchus, Anatoliy Lokha http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18847 Fri, 02 Sep 2022 00:00:00 +0000