All Articles

Summary: In this work have been presented the result of investigation of K0,945Ag0,055NO3 and K0,945Cs0,055NO3 single crystals were grown from aqueous solution of KNO3, AgNO3 and CsNO3 using isothermal crystallization method. Then, structural and phase transformations in samples were studied by X-ray and optical microscopy methods. It has been determined that in K0,945Ag0,055NO3 monocrystal at T393K temperature, in K0,945Cs0,055NO3 monokrystal at T455K temperature the rhombic (II)  hexagonal (III) transformation occurs with the formation and growth of the III - modification crystal embryo within II – modification. The results obtained from the kinetic studies were determined that the temperature dependence of the conversion rate of II  III in K0,945Ag0,055NO3 and K0,945Cs0,055NO3 single crystals can be expressed by an empirical formula of υ=(aΔT+bΔT^2+cΔT^3)⋅10^(-2) cm/sec. ΔT=T_t-T_0 is temperature delay, T_t- is transformation temperature and is equilibrium temperature between interconverting modification crystals. Based on the results of velocity measurements, the activation energy of IIIII polymorphic transformations were calculated.

Summary: The article presents mathematical modeling and experimental study of microwave waveguide taking into account boundary value problems on the geometric middle of the domain. For the first time, general classes of local and nonlocal boundary value problems on the geometric middle of the domain for three-dimensional Bianchi-type equations for the electromagnetic field of microwave rectangular waveguide are investigated. New mathematical models of the electromagnetic field of microwave rectangular waveguide operating in the frequency range of 4,9-7,05 GHz are developed taking into account the nonlinearity of the medium, wave types and effective algorithms for solving the models are proposed, which made it possible to improve the electrical, magnetic, structural and operational parameters and characteristics of microwave rectangular waveguide. For E-type and H-type waves, 3D models of the distribution of electromagnetic field strengths in elementary regions of rectangular waveguide are developed. Experimental devices and functional circuits for measuring the parameters of the microwave path, including the electric and magnetic fields of a rectangular waveguide in a nonlinear state of the medium, were developed, and the parameters of the microwave rectangular waveguide were experimentally determined. Comparison of theoretical and experimental results of the electric and magnetic field strengths showed that the relative error for these parameters is 4%. This proved the adequacy of the theoretical and experimental results obtained. The proposed work differs from the existing [1-5] works in that, in this work, for the first time, the factor that the studied microwave waveguide is filled with nonlinear media is taken into account.

Summary: Nowadays, beams, boards and coatings with new complex properties are widely used in many branches of mechanical engineering and construction. The calculation and analysis of the amplitude characteristics of stability, strength and frequency of a structural element with these properties lead both to significant difficulties in mathematical terms and to the analysis of the results obtained, if ignored, serious errors may be made. Taking these into account, it becomes necessary to build mathematical models characterizing the real properties of the material when using a structural element made of new materials and establishing effective physical connections. There are materials in which the tensile strain diagrams characterizing their properties are diverse in tension-compression and torsion. Such materials include ceramics, some types of copper and cast iron, polymers, and composite materials. The mechanical and physical properties of these materials become strictly dependent on hydrostatic pressure. For materials with the above-mentioned specific property, classical elasticity and elastoplasticity cannot be considered under the conditions accepted by the theory of plasticity. In this paper, a problem of planar stability of an elastic, plastic plane differently resisting to tension and compression in pure bending is solved. It is assumed that the cross-section of the beam has one symmetry axis, under the action of concentrated moments applied at the ends of the bar is subjected to pure bending, and bending happens in the symmetry plane of the beam. Using the state of a neutral axis, absence of longitudinal force, continuity conditions for tension and compression, we determine the boundary of elastic and plastic domains. The equations of the loss of planar stability obtained for the classic case are reduced to the loss of planar stability for various modulus ideal elastic and plastic beams. The expressions of hardness for different modulus materials are obtained and are associated with critical moment and critical length. Expressions for calculating critical parameters for an ideally elastic, plastic beam with a rectangular cross section are obtained.

Summary: Increasing the properties of iron-based abrasive composition materials by volume and surface alloying is of scientific and technical importance. Since increasing the properties of composite materials by volume alloying causes a number of difficulties, surface alloying is often used to improve the properties of this type of materials. Therefore, in order to increase the properties, successive saturation processes of their surface layer with one or more carbide-forming elements are carried out. It was found that the properties enhancement with one-component coatings differs from the properties of multi-component coatings. It is clear that as a result of the saturation of the surface layer of the abrasive composition materials with certain elements, coatings with different composition are created in them. Carbide, nitride, boride and other coatings allow to obtain the necessary results. Therefore, the improvement of the structure and properties of iron-based abrasive composition materials directly depends on the coatings formed as a result of hammering the surface layer of construction materials with various elements. In the article, the effect of carbide, nitride and boride-containing coatings on the structure and properties of iron-based abrasive composition materials was considered. The distribution of chromium in the depth of the diffusion layer was studied by the method of micro-X-ray spectral analysis. The greatest concentration of chromium is observed on the surface, which increases as the degree of carbonization of the material increases. The change of the amount of chromium on the depth of the carbide zone obeys a linear law. At the boundary of the carbide zone, its concentration is approximately the same in the studied materials and is 58-61% In connection with the increase in the initial carbonization degree of the surface zone, the increase in the concentration of chromium is accompanied by the increase in the microhardness of the carbide coating. Based on the data of X-ray structural studies, the studied carbide coatings have the same phase composition (Cr, Fe) C 23 6, (Cr,Fe) C 7 3. The structure of the transition zone and its layers is determined by the degree of carbonization of the material during the initial processing. At relatively low temperatures (875 and 925 °C) in cementitized iron, as in the case of JQr 0.5 composition, a weakly tanned zone (20-25 μm thick) of an extremely saturated γ-solid solution with a microhardness H100 = 6100-7000 MPa, formed in the process of cooling from the air chroming temperature directly under the carbide layer is located. Behind it is a zone of high etching ability, which is caused by the eutectoid decomposition of the solid solution of chromium and carbon in γ-iron. The intermediate zone of annealed iron cementitized at 975-1025 °C undergoes eutectoid decomposition during cooling in air and metallographically is detected as a band with high etching ability.

Summary: This paper explores the effect of oil price, gross domestic product (GDP), and carbon dioxide (CO2) emissions on renewable energy consumption in China from 1990 to 2020, utilizing the canonical cointegrating regression (CCR) method. The findings indicate that the oil price, GDP and CO2 emissions positively and significantly affect renewable energy consumption over the examined time frame. Numerically, a 1% increase in oil prices, GDP, and CO2 emissions results in a 0.16%, 0.39%, and 1.70% increase in renewable energy consumption, respectively. The positive effect of oil prices on renewable energy consumption can be seen as the cost advantage of renewable energy, which may grow with rising oil prices, leading to a rise in its adoption. The study underscores the significance of promoting renewable energy usage, emphasizing the need for policies that aid energy security and environmental sustainability.

Summary: Exploring the relationship between international oil prices, income, and carbon dioxide (CO2) emissions in Saudi Arabia, this study examines if renewable energy consumption plays a lowering tool in international oil prices' impact on CO2 emissions, employing conventional econometric methods and the functional coefficient approach. The study reveals that the interaction between renewable energy consumption and international oil prices has a negative and statistically significant impact on CO2 emissions. This emphasizes the potential for Saudi Arabia to reduce carbon emissions by prioritizing renewable energy projects. In addition, a positive and statistically significant relationship between income and CO2 emissions is found, emphasizing the need to decouple economic growth from emissions growth. Furthermore, an interesting decoupling effect between oil price elasticity of CO2 emissions and per capita GDP is noted from the early 2000s–2015. This indicates that economic growth driven by rising oil prices can be managed to mitigate environmental impact, showcasing Saudi Arabia's commitment to sustainable development. Policy recommendations involve intensifying efforts to promote renewable energy implementation, lowering fossil fuel dependence in power generation, and incentivizing emissions reduction for a more sustainable energy future.

Summary: Tutorials, textbooks, studentbooks usually provide students writing, reading materials or stories where learners can enhance the topics very well. Comprehension of texts motivates the reader not only to understand the texts but also to perform tasks related to the text. For this reason, analysis of texts can profoundly aid the comprehension process. There are different approa-ches to conducting analysis, but the most common form is the close reading, which allows students feel the events in stories to its least details. Thus, research work creates mutual interactivity between the author, teacher and reader based on reading textbook materials and reveals methods of complex scientific analysis.

Summary: In recent years, the subject of risk management has received increasing attention both in the academic literature and in the world of business and management. This method aims to eliminate potential threats in a planned and programmed manner and to create plans to intervene in the situation before possible negative events occur. In this article, first of all, what is the risk? Risk management in a higher education institution and what the risks are, followed by explanations about the statistical data obtained as a result of the survey research conducted by (BEU) (with the participation of students studying in the 2023-2024 academic year).

Summary: In view of the above, the article explores the principles and main directions of national-patriotic chemistry education of 10-11th grade pupils in post-2nd Karabakh War period and searches the answers to questions, do we need to instill patriotism in our children, how it acts on their worldview and motivation to science education. Methods of data acquisition - questionnaire and quantitative data processing with methods forecasting analytical methods in data software Numbers was used. So, chemical education in the post-war period should be patriotically directed, which creates additional motivation for learning. n, modern education realized as indestructible complex with many other subjects.

Summary: The article presents a theoretical and experimental assessment of noise levels during the analog-to-digital conversion of TV broadcast microwave signals. Mathematical expressions are derived to calculate the mean quantization noise power for different brightness distribution models on TV images, considering both linear and nonlinear characteristics of the “light-to-signal” converter. For the first time, the dependence of the average quantization noise power on the compression coefficient is obtained for an inversely proportional distribution of brightness on the television image. This is particularly relevant when the input unipolar positive TV broadcast luminance signal is small, i.e., when the signal level is below the first quantization level. Additionally, analytical expressions are provided to calculate the level of restriction noise and the ratio of restriction noise power to quantizing noise power, particularly when the brightness distribution on TV images follows an exponentially decreasing model or an inversely proportional model with a logarithmic quantization scale. The impact of quantization and restriction noise on image quality was experimentally tested in an Additive White Gaussian Noise (AWGN) channel.