Інститут Шосткинський (ШІ)
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Item Кінетика процесу нітрування крохмалю нітратною кислотою(Oles Honchar Dnipro National University, 2022) Лукашов, Володимир Костянтинович; Lukashov, Volodymyr Kostiantynovych; Тищенко, Сергій Дмитрович; Tyshchenko, Serhii Dmytrovych; Шевцова, Тетяна Миколаївна; Shevtsova, Tetiana Mykolaivna; Середа, Віта Іванівна; Sereda, Vita IvanivnaСтаття присвячена експериментальному дослідженню процесу нітрування крохмалю нітратною кислотою (в суміші з водою). Такий спосіб нітрування має ряд переваг у порівнянні з використовуваним у промисловості способом нітрування нітратно-сульфатнокислотною сумішшю. Метою дослідження було встановлення кінетичних закономірностей процесу нітрування, необхідних для обґрунтування технологічних режимів його проведення. Методика дослідження полягала в обробці крохмалю кислотою та визначенні зміни вмісту нітрогену в одержуваному нітраті крохмалю в часі за різних параметрів процесу нітрування. На підставі результатів дослідження встановлено, що процес нітрування крохмалю нітратною кислотою протікає одночасно з його розчиненням і включає дві стадії: швидку, пов’язану з розчиненням аморфних областей крохмальних зерен, і повільну – з розчиненням їх кристалічних областей. Вміст нітрогену в нітраті крохмалю на другій стадії набуває значення, близького до постійного, через неповне розчинення найбільш досконалих фрагментів кристалітів. Показано вплив параметрів процесу нітрування на його кінетику. Виявлено, що в логарифмічних координатах кінетичні залежності нітрування лінеаризуються зі зламом під час переходу від першої до другої стадії, що дозволило в якості їх математичного опису використовувати ступеневу функцію. В результаті обробки експериментальних даних одержано емпіричні рівняння для розрахунку кінетики процесу нітрування.Item Didactic Principles Of Education Students 3D-printing(International Journal of Computer Science and Network Security, 2022) Lukianchuk, I.; Tulashvili, Y.; Podolyak, V.; Horbariuk, R.; Kovalchuk, V.; Базиль, Сергій Михайлович; Базыль, Сергей Михайлович; Bazyl, Serhii MykhailovychThe method of studying 3D-technologies abroad and in Ukraine is considered. The analysis of educational resources and experience of use of the equipment in branch is carried out. The didactic principles of the educational process for 3D-printing specialists are determined. The use of FDM technology and the ability to minimize the occurrence of defects in the future have been studied. An analysis of the international experience of the educational process of relevant specialists in the field. The content of training for 3D printing specialists has been developed. The experience of using 3D-technologies is described and the list of recommendations for elimination of defects during production of products by means of additive technologies is made. The recommendations will be useful not only for beginners, but also for experienced professionals in additive technologies. The need to study such experience is the main condition for the development of enterprises in Ukraine that plan to automate their own production. A 3D printing engineer must know the basics of economics and marketing, because his responsibilities include optimizing workflows to reduce the cost and speed up printing. Therefore, the knowledge gained from practical experience presented and in building for learning 3D printing engineers by the authors will be important.Item Electromagnetic Performance of Waveguide Polarizers with Sizes Obtained by Single-Mode Technique and by Trust Region Optimization(Advanced Electromagnetics, 2022) Piltyay, S.; Bulashenko, A.; Kalinichenko, Y.; Bulashenko, O.V.Modern wireless networks, stationary terrestrial and satellite systems use many modern technologies to increase communication channels information capacity. They save limited frequency resources. In satellite communications the polarization signal processing is applied to reuse the allocated frequency bands. Usage of circularly polarized electromagnetic waves, which transmit useful signals, reduces fading effects and eliminates disadvantages introduced by multipath propagation interferences. In this case the distortion levels for signals with an odd number of electromagnetic waves reflections in the receiving antenna systems will be reduced down to the thresholds of their cross-polarization isolation. Besides, in the case of orthogonal polarizations usage, the achieved information capacity of the applied wireless communication channel multiples almost by the factor of two. The type of polarization of the used electromagnetic wave strongly determinates the peculiarities of the process of its propagation in the space or transmission line. Polarization signal processing is frequently carried out in horn feed systems of the reflector antennas. Such feed networks and systems allow to transmit and receive signals with several kinds of polarization at the same time. The fundamental element of dual circular polarization antenna feed networks is a waveguide polarization duplexer. The phase, isolation and matching characteristics of a polarization converter strongly influence on the functionality and polarization discrimination possibilities of the entire reflector antenna system. Therefore, the development and optimization of the characteristics of waveguide polarizers for satellite communication antennas is a crucial technical problem, which must be solved by fast and accurate methods. The comparison of electromagnetic performance of waveguide polarizers with sizes obtained using a fast single-mode technique and by more accurate trust region optimization method is carried out in this research. The results for differential phase shift, level of voltage standing wave ratio, ellipticity coefficient and cross-polarization discrimination are shown and discussed.Item Accuracy and Agreement of FDTD, FEM and Wave Matrix Methods for the Electromagnetic Simulation of Waveguide Polarizers(Advanced Electromagnetics, 2022) Bulashenko, A.; Piltyay, S.; Polishchuk, A.; Bulashenko, O.; Kushnir, H.; Забегалов, Ігор Вікторович; Забегалов, Игорь Владимирович; Zabehalov, Ihor ViktorovychWaveguide devices of polarization processing are key elements of modern dual-polarized antenna systems. Such antenna systems carry out polarization transformation and separation of signals with orthogonal polarizations in satellite communications and radar appliances. Well-known electrodynamic methods are used to simulate performance of such devices. This paper investigates the accuracy and mutual matching of wave matrix method with FDTD and FEM. The wave matrix method is based on the theory of scattering and transmission matrices. The main electromagnetic characteristics of a polarizer were obtained through the elements of these matrices. The main characteristics of a polarizer were compared. They include phase difference of orthogonal polarizations, level of voltage standing wave, ellipticity coefficient and level of cross-polarization isolation. Comparison of electromagnetic characteristics was carried out at the example of a waveguide iris polarizer for the operating frequency range from 13.0 to 14.4 GHz. In addition, the process of optimization of electromagnetic characteristics was carried out by changing the geometric dimensions of a polarizer. Calculated by different theoretical methods characteristics were compared and analyzed. Results, which were obtained by considered methods, are in good agreement.Item Compact 2-step Septulum Polarization Converters for Radars and Satellite Systems(Advanced Electromagnetics, 2022) Piltyay, S.; Bulashenko, A.; Fesyuk, I.; Bulashenko, O.This article presents the results of analysis, numerical simulations and optimization of new narrowband guide septulum polarization converters. Orthomode duplexers and polarization converter designs based on septulums are widely used in modern microwave systems with orthogonal circularly polarized signals. Septulum guide polarizer is an effective compact device, which transforms right-hand circularly polarized (RHCP) and left-hand circularly polarized (LHCP) electromagnetic modes into linearly polarized ones. At the same time, it divides RHCP and LHCP modes and directs them to two different rectangular guides with high signal discrimination to each other. Thus, a septulum-based guide device integrates performance of a polarization transformer and of an orthomode duplexer. The main electromagnetic characteristics of the suggested polarization converter were simulated using the finite elements method. The proposed design of a compact narrowband guide polarization converter has a septulum with two steps. Several designs of septulum polarization converters were developed and compared for different relative bandwidths of 5%, 10%, and 15%. The comparative investigation of the obtained designs was carried out. Main electromagnetic characteristics of optimal septulum polarization converters were modeled and compared in considered fractional bandwidths. These include reflection coefficients, cross-polarization discrimination, ellipticity parameter, and ports discrimination. Developed compact septulum polarization converters can be applied in modern antenna systems for radars and satellite communication systems.