Volodymyr Kucheruk

This study examines the time-resolved photoluminescence spectra of zinc selenide (ZnSe) single crystals, both undoped and doped with the isovalent tellurium impurity, at 83 K, together with their steady-state photo luminescence spectra. The ZnSe crystals were excited using a nitrogen laser with a wavelength of 347 nm. In the steady-state photoluminescence spectra of undoped ZnSe, three emission bands were observed, with max ima at approximately 443, 458, and 610 nm. Time-resolved luminescence spectroscopy made it possible to resolve the 610 nm band into two components, with maxima near 580 and 640 nm. In the steady-state spectra of tellurium-doped ZnSe crystals, three emission bands were also detected, with maxima at approximately 450, 505, and 640 nm. Time-resolved photoluminescence spectra allowed the 505 nm band to be resolved in to two components, with maxima near 485 and 510 nm. The intensity of the red emission band at 640 nm in creases with increasing tellurium concentration. It is hypothesized that this red photoluminescence band is as sociated with an intracentric transition of an associative defect involving a zinc vacancy, an interstitial zinc atom, and a tellurium atom substituting for selenium. Considering the presence of an uncontrolled aluminium impurity in the crystals, an alternative interpretation is also possible: the 640 nm band may originate from an intracentric transition within a defect complex comprising a zinc vacancy, an aluminium atom substituting for zinc, and a tellurium atom substituting for selenium.

The article defines the conditions under which continuous current control of electrical power consumption in large, branched high-voltage electrical networks is possible. The fact is that for complete hardware current continuous control of electrical power consumption, it is necessary to have active and reactive power sensors at each node of the electrical network (at each substation) and their connection with dispatching control centers. For countries with large distances between grid nodes and control centers, this requires huge capital expenditures. Therefore, it is much more expedient to place power and voltage sensors in separate nodes and then calculate the remaining nodes using Kirchhoff's laws. Under these conditions, the system of equations using the nodal potential method becomes non-canonical, that is, the known parameters in it are part of the nodal currents and part of the nodal potentials. Such a system does not always have a unique solution, and it depends on the correct placement of power and voltage sensors. But the placement of sensors must be carried out before calculations, therefore the task of determining the conditions for correct placement of sensors without preliminary calculations is relevant, which is considered in the article.

У роботі проаналізовано ключові критерії ефективності штучних нейронних мереж: точність прогнозування, швидкість навчання, витрати ресурсів та здатність до узагальнення. Мета дослідження – систематизувати показники та методи порівняльної оцінки різних архітектур. Запропоновано експериментальну методологію оцінювання на реальних даних. Практична значущість – сприяння оптимальному підбору та налаштуванню мереж для прикладних задач, підвищення якості результатів при мінімальних витратах ресурсів.

The object of the study is the development of a device capable of accurately and reliably measuring heat flux density in various environments. The development of a heat flux density meter designed for non-destructive analysis of thermal processes in various fields of application is presented. The developed device is intended for evaluating the thermal insulation condition of underground pipelines. The functionality of the heat flow device relies on comparing standard temperature values with experimental ones measured on the soil surface. To ensure accurate and reliable measurement of heat flux density, the basis is a thermoelectric battery converter, which uses the auxiliary wall method. The heat flow density measuring device is constructed in the shape of a restricted cylinder, with one base serving as the working surface, while the second base establishes thermal contact with the body at ambient temperature. Embedded heaters enable the generation of heat flow through the thermoelectric sensor in directions perpendicular to its base. For calibrating the heat flux device, experiments were conducted using a standard copper-constantan calibration table. Temperature increments were determined from thermo electromotive force, and tests were performed on an existing heating network. The conducted measurements validate the fundamental feasibility of employing the proposed device for implementing the non-destructive thermal testing method on underground heating mains. The results of the experiment can be used not only for research, but also for monitoring and regulating processes in various fields of science and technology. The developed heat flux meter promises a significant contribution to the development of modern methods for analyzing thermal processes. The dimensions of the thermoelectric battery converter are also determined and the coefficient (kq) should be in the range from 4.0 to 12.0 W/(m2⋅mV), and the electrical resistance should be in the range of 12–20 kOhm

У роботі запропоновано інформаційну систему для доїльної установки з молокопроводом, яка є інноваційним рішенням що надає можливість користувачу у будь-який момент часу, за допомогою смартфона, персонального або планшетного комп’ютера отримувати інформацію про параметри технологічного процесу виробництва коров’ячого молока, контролювати події, які відбуваються на доїльній установці, виявляти аварійні ситуації та факти порушень регламенту роботи персоналом ферми, здійснювати облік удою.