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.

In this work, the synthesis of nickel particles encapsulated in a few-layer graphene shell was carried out using the method of electric arc discharge in the liquid phase, in various media: deionized water, alcohol, and toluene. Nickel and graphite were used as electrodes. The study was carried out to analyze how various liquids, acting as a cooling medium and a source of carbon, affect the formation of a protective shell around metal particles. Raman studies, analysis of X-ray diffraction data, and scanning electron microscopy confirmed the formation of spherical encapsulated nickel particles in all types of liquid media. It was found out that the use of toluene as a cooling medium increased the number of particles with a graphite shell and allowed obtaining micro- and nanoparticles covered with monolayer graphene. The absence of oxygen in the composition of toluene, in contrast with alcohol and especially water, prevents the oxidation of nickel particles during the synthesis. This fact, along with the initial basic hexagonal carbon structure of toluene, makes it a good medium for the formation of metal particles covered with a protecting graphite shell as a result of arc discharge in the liquid phase.

The work is devoted to measuring linear displacements in the nanoscale, analysing the features of this kind of work, ensuring the unity of measurements and stability of the measured physical quantity, the reliability of the results and their linkage to the State Standard. The criteria must be met by methods and means of precision measurements in the nanoscale, as well as methods and means for acquiring and presenting the information obtained. The analysis of the main sources of errors is made and the results of these studies are presented in Novikov [1]. The features of the construction of measuring systems, as well as the problems of calibration of phase measurements in optics, are considered. The problems of an applied nature are considered: the measurement of real displacement of objects in the nanoscale, their speed and acceleration, as well as the introduction of the developed methods into the field of practical application. The results obtained in solving experimental and applied problems using methods and means of numerical heterodyning are presented. The developed 'interferometer-phase meter' measuring system allows online investigating of complex piezoceramic structures used in various devices as actuators.

In this work, monovalent copper oxide (Cu2O) powders were synthesized, and studied as a material for the photochemical decomposition of water to hydrogen using sunlight. The chemical precipitation room temperature using ascorbic acid has been applied to the synthesis of powders. The production method is energy efficient, economical, fast and efficient compared to other methods. The morphology of the synthesized samples obtained by scanning electron microscopy are presented. As a result, homogeneous cubic Cu2O microparticles were obtained. An elemental composition using energy dispersive analysis is confirmed. Structural characteristics are also investigated using Raman spectroscopy and X-ray diffraction analysis. A technology for manufacturing an electrode based on synthesized powders on nickel foam was developed to study the electrochemical properties. An electrochemical characteristic as cyclic voltammetry is obtained, showing excellent redox properties. The photocatalytic properties of powders are also being studied to obtain them as photocatalysts for the decomposition of an alcohol solution in order to produce hydrogen. The photocatalytic activity of copper oxide powders for the photochemical reduction of water has been found, which makes it an interesting material for further research. В настоящей работе порошки одновалентного оксида меди (Cu2O) синтезированы и исследованы в качестве материала для фотохимического разложения воды на водород с помощью солнечного излучения. Химическое осаждение при комнатной температуре с использованием аскорбиновой кислоты был применен для синтеза порошков. Способ получения является энергоэффективным, экономичным, быстрым и простым по сравнению с другими существующими методами. Приведены данные по морфологии синтезированных образцов, полученные методом сканирующей электронной микроскопии. В результате получены однородные Cu2O микрочастицы кубической формы. Подтвержден элементный состав с помощью энергодисперсионного анализа. Также исследованы структурные характеристики с помощью Рамановской спектроскопии и рентгеноструктурного анализа. Была отработана технология изготовления электрода на основе синтезированных порошков на никелевой пене для изучения электрохимических свойств. Электрохимическая характеристика как циклическая вольтамперограмма была получена, демонстрирующая отличные окислительно- восстановительные свойства. А также исследованы фотокаталитические свойства порошков для применения их в качестве фотокатализаторов для разложения спиртового раствора с целью получить водород. Выделение водорода определялся хромотографическим методом. Обнаружена фотокаталитическая активность порошков оксида меди для фотохимического восставновления воды, что делает его интересным материалам для дальнейшего исследования. Бұл жұмыста бір валентті мыс оксиді (Cu2O) ұнтақтары синтезделіп, күн сәулесінің көмегімен суды сутегіге фотохимиялық ыдырату үшін арналған материал ретінде зерттелген. Ұнтақтарды синтездеу үшін аскорбин қышқылын пайдаланып бөлме температурасында химиялық тұндыру әдісі қолданылды. Бұл әдіс басқа қолданыстағы әдістермен салыстырғанда энергияны үнемдейтін, тиімді, жылдам және қарапайым болып табылады. Сканерлеуші электронды микроскоп арқылы алынған синтезделген үлгілердің морфологиясы туралы деректер келтірілген. Нәтижесінде біртекті текше Cu2O микробөлшектері алынды. Элементтердің құрамы энергиялық дисперсті талдау арқылы расталды. Құрылымдық сипаттамалары сонымен қатар Раман спектроскопиясы мен рентгендік дифракциялық талдау арқылы зерттелді. Электрохимиялық қасиеттерін зерттеу үшін никель көбікте синтезделген ұнтақтардың негізінде электрод жасау технологиясы оңтайланды. Өте жақсы тотығу-тотықсыздану қасиеттерін көрсететін циклдік вольтаммограмма ретінде электрохимиялық сипаттама алынды. Сондай-ақ...

This paper presents a hybrid approach for predicting pollutant dispersion in urban street canyons, taking into account noise barriers. The methodology combines detailed CFD modeling and a surrogate model based on the BiLSTM neural network architecture with an attention mechanism. Configurations with barrier heights of 0.1H, 0.2H, and 0.3H were studied. CFD calculations revealed a nonlinear effect of barrier height on aerodynamics and the formation of pollutant accumulation zones, with the most complex non-stationary behavior observed at a height of 0.2H. The surrogate model successfully predicts concentration evolution for both the barrier-free and 0.1H barrier cases, demonstrating an average absolute percentage error of less than 15%. For a 0.2H barrier, accuracy decreases in zones of intense turbulence due to the highly non-stationary nature of the process. This approach significantly reduces computational costs while maintaining physical accuracy, which is promising for decision support systems in urban ecology. The model provides accelerated forecasting compared to CFD calculations by 7–8 orders of magnitude, so the inference time showed 1–5 ms, while one CFD simulation takes about 54 hours on the CPU.

This study investigates methods for forming hydrophilic and superhydrophobic surfaces using plasma jets at atmospheric pressure. The primary focus is on ensuring the waterproofing of fabrics by creating superhydrophobic coatings. The influence of plasma on the structural and chemical characteristics of the treated materials was analyzed, along with the impact of key technological parameters, including discharge power and the composition of the plasma-forming gas. In the experiments, argon (Ar) was used as the main gas flow, while hexamethyldisiloxane (HMDSO) vapor served as the precursor. The hydrophilic properties of the surface were examined after one and ten treatment cycles using plasma in an argon flow at a rate of 40 mL/s with a power of 200 W under atmospheric pressure. The experimental parameters for the formation of the superhydrophobic coating included a discharge power of 200 W, an Ar flow rate of 40 mL/s, and a gas mixture flow rate of Ar + HMDSO at 20 mL/min. After plasma treatment, the contact angle was measured to evaluate changes in surface hydrophilicity and superhydrophobicity depending on the treatment parameters.The results confirmed the effectiveness of plasma modification for controlling the hydrophobic properties of materials. Furthermore, the stability of the coatings in contact with various liquids was investigated.