Chronopotentiometry at platinum electrode in KF-NaF-AlF3-Al2O3 melt

Some features of the mechanism of the anode process on platinum in KF–NaF–AlF3–Al2O3 melt at 750–780 °C depending on the of anodic current density (0.5 mA/cm2 to 2.0 A/cm2) and anodic pulse duration have been studied using chronopotentiometry method. In curves of change in the platinum anode potential a small peak at current densities of 10–30 mA/cm2 and a clear peak at current densities of 0.5–2.0 A/cm2 are recorded when the current is cut on. Analysis of dependencies of the transition time on the current density indicates that the first peak in curve is associated with the formation of an oxide compound on the platinum surface, and the second one is related to hindering the diffusion for delivery of electroactive particles to its surface.The study was supported by the Russian Foundation for Basic Research (grant № 13–03–00829 A)

Исследование эффективности автоматической системы обнаружения и распознавания объектов на радиолокационном изображении с применением нейронных сетей

The main factors influencing the efficiency of an automatic object recognition system in a radar image obtained with a synthetic aperture radar are considered A clustering algorithm of selecting objects on a radar image has been developed. The results of applying the radar image clustering algorithm, which makes it possible to increase the probability of correct recognition of objects, are presented. An analysis of the effectiveness of the application of the clustering algorithm depending on the threshold detection is given. The structure of the two-stage system of the algorithm of the automatic recognition of objects on a radar image has been developed and presented.  Weber V. I., Kuprits V. Y., Zaikov K. D. Research of the efficiency of the automatic system of detection and recognition of objects on radar image using neural networks. Ural Radio Engineering Journal. 2022;6(3):225–309. (In Russ.) DOI: 10.15826/urej.2022.6.3.004. Рассмотрены основные факторы, влияющие на эффективность автоматической системы распознавания объектов на радиолокационном изображении, полученном с помощью радиолокатора с синтезированной апертурой антенны. Разработан алгоритм кластеризации для выделения объектов на радиолокационном изображении. Приведены результаты применения алгоритма кластеризации радиолокационного изображения, позволяющего повысить вероятность правильного распознавания объектов. Приведен анализ эффективности применения алгоритма кластеризации в зависимости от порогового обнаружения. Разработана и приведена структура двухэтапной системы алгоритма автоматического распознавания объектов на радиолокационном изображении.  Вебер В. И., Куприц В. Ю., Зайков К. Д. Исследование эффективности автоматической системы обнаружения и распознавания объектов на радиолокационном изображении с применением нейронных сетей. Ural Radio Engineering Journal. 2022;6(3):296–309. DOI: 10.15826/urej.2022.6.3.004.

АНАЛІЗ ДІАГНОСТИЧНИХ ПАРАМЕТРІВ ІМУНОБЛОТИНГУ РІЗНИХ ВИРОБНИКІВ ДЛЯ ВИЗНАЧЕННЯ СЕНСИБІЛІЗАЦІЇ ДО ПИЛКОВИХ АЛЕРГЕНІВ У ПАЦІЄНТІВ ІЗ РЕСПІРАТОРНИМИ АЛЕРГІЧНИМИ ЗАХВОРЮВАННЯМИ

In the context of the large amount of sometimes unfair information, the physician is not always able to understand the advantages and disadvantages of each method and correctly evaluate the parameters of their diagnostic value. The aim of the study – to compare the diagnostic parameters of different systems of serological examination by immunoblot method for the determination of sensitization to allergens of pollen group in patients with respiratory allergic diseases – allergic rhinitis and bronchial asthma. Materials and Methods. In the study, 88 patients with allergic rhinitis and/or atopic asthma were examined with three different methods of specific allergic diagnosis (in vivo and in vitro). Inclusion criteria were a diagnosis of allergic rhinitis (both intermittent and persistent) and/or atopic asthma. The prick test was conducted according to the classic test method according to the normative documents with commercial allergen extracts.  Western blots for the determination of IgE levels were performed using RIDA AllergyScreen test systems (R-Biopharm AG, Darmstadt, Germany) and Euroline (Euroimmun). Results. The results of two systems for determining specific IgE for pollen allergens by the Rida AllergyScreen and Euroline methods do not always agree very well due to the systematic divergence of indicators. The results of determining specific IgE for individual allergens are generally in good agreement with each other and the results of skin testing by the prick test, however, for wormwood, birch, hazel and alder pollen allergens, the Euroline system does not always match the results of skin testing by the prick test negative results. Conclusions. Further analysis of the consistency and diagnostic parameters of the methods for other allergen groups is necessary to summarize all the results of the study.В умовах великого обсягу іноді заангажованої інформації лікар не завжди здатний зрозуміти переваги та недоліки кожного з методів та правильно оцінити параметри їх діагностичної цінності. Мета дослідження – порівняти діагностичні параметри різних систем серологічного дослідження методом імуноблоту для визначення сенсибілізації до алергенів пилкової групи у пацієнтів із респіраторними алергічними захворюваннями – алергічним ринітом та бронхіальною астмою. Матеріали і методи. У ході дослідження обстежено 88 пацієнтів з алергічним ринітом та/або атопічною астмою за допомогою трьох різних методів специфічної алергічної діагностики (in vivo та in vitro). Критеріями включення були діагноз алергічного риніту (як інтермітуючого, так і персистуючого) та/або атопічної астми. Прик-тест проводили за класичною методикою тестування відповідно до нормативних документів із комерційними екстрактами алергенів. Вестерн-блот для визначення рівнів IgE виконували з використанням тест-систем RIDA AllergyScreen (R-Biopharm AG, Дармштадт, Німеччина) і Euroline (Euroimmun). Результати. Результати двох систем визначення специфічного IgE до алергенів пилкової групи методами Rida AllergyScreen та Euroline не завжди дуже добре узгоджуються між собою унаслідок систематичного розходження показників. Результати визначення специфічних IgE до окремих алергенів у цілому добре узгоджуються між собою та результатами шкірного тестування методом прик-тесту, втім до пилкових алергенів полину, берези, ліщини та вільхи система Euroline не завджи узгоджується з результатами шкірного тестування методом прик-тесту, даючи хибно-негативні результати. Висновки. Подальший аналіз узгодження та діагностичних параметрів методів в інших групах алергенів є необхідним для узагальнення усіх результатів дослідження

High-temperature electrochemistry of calcium

Electrolytically produced calcium is one of the most demanded materials in obtaining pure materials. At the same time, the existing technologies and devices for the electrolytic production of calcium were developed in the last century, and at present there are practically no works aimed at optimizing them. However, increasing the capacity and efficiency of existing devices for the production of calcium is in demand. To analyze possible ways to improve calcium production, a comprehensive understanding of the processes occurring at the electrodes and in the electrolyte during electrolytic production of calcium is required.This review briefly outlines the main points concerning the electrolytic production of calcium: from a brief history of the development of methods for the electrolytic production of calcium and established ideas about its physicochemical processes to information about new developments using the electrolysis of CaCl2-based melts. Review content: brief history of process development; base electrolyte for calcium production, including preparation of CaCl2 and influence of additions on it physicochemical properties; data on calcium solubility in CaCl2; information about alternative electrolytes for calcium production; short description of electrode processes in the CaCl2-based melts; proposed technologies and devices for the electrolytic production of calcium. keywords: calcium, calcium chloride, ion-electron liquid, Cu–Ca alloy, molten salt, calcium solubility, electrode processes, inert anode, electrolysis, current efficiency, electrolyzer DOI: https://doi.org/10.15826/elmattech.2022.1.00

Molecular dynamics study of the stability of aluminium coatings on iron

Among the available protection systems for steel, the use of coatings is the most popular and economical method. One can protect the steel electrode from aggressive media with an aluminum coating. A thin Al film on an Fe substrate has been studied by the molecular dynamics method at a heating temperature from 300 K to 1500 K. A significant horizontal displacement of individual Al atoms on the edges of the film is observed during the simulation. The film begins to “spread” slightly near the edges. This “spreading” creates the conditions for the beginning of diffusion of iron atoms into aluminum. Some Al atoms were found to penetrate the Fe matrix at a temperature of 873 K. The total energy curve of the system shows both the melting transition in aluminum and phase transition from the body-centered cubic lattice to the face-centered cubic one at 1173 K. The binding energy for the Al atom in the lattice of the Fe crystal is smaller than that for Fe atoms. The calculated diffusion coefficients for Al and Fe have a significantly slower growth with a temperature in the range of 673 K ≤ T ≤1500 K. To describe the diffusion in a crystal using the molecular dynamics model, a temperature-dependent correction to the activation energy is calculated. The temperature dependence of the diffusion coefficient of aluminum atoms in an iron crystal can be represented as an Arrhenius expression with a temperature-dependent energy barrier for diffusion. © 2019, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved

High-Temperature Electrochemistry of Calcium

Received: 12 July 2022. Accepted: 03 September 2022.Electrolytically produced calcium is one of the most demanded materials in obtaining pure materials. At the same time, the existing technologies and devices for the electrolytic production of calcium were developed in the last century, and at present there are practically no works aimed at optimizing them. However, increasing the capacity and efficiency of existing devices for the production of calcium is in demand. To analyze possible ways to improve calcium production, a comprehensive understanding of the processes occurring at the electrodes and in the electrolyte during electrolytic production of calcium is required. This review briefly outlines the main points concerning the electrolytic production of calcium: from a brief history of the development of methods for the electrolytic production of calcium and established ideas about its physicochemical processes to information about new developments using the electrolysis of CaCl2-based melts. Review content: brief history of process development; base electrolyte for calcium production, including preparation of CaCl2 and influence of additions on it physicochemical properties; data on calcium solubility in CaCl2; information about alternative electrolytes for calcium production; short description of electrode processes in the CaCl2-based melts; proposed technologies and devices for the electrolytic production of calcium

Анодный процесс на платине в расплаве на основе CaCl2-CaO

Methods potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic processes on platinum in the molten CaCl2-KCl-CaO when 725–775 °C. Given thermodynamic values of potential difference probable total reactions in the range of the studied temperature. Using potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic process on platinum in the molten CaCl2-KCl-CaO when 725–775 °C thermodynamic assessment of the probability of occurrence total reactions during electrolysis melt on the basis of CaCl2-CaO using non-carbon anode. It is shown that at high current densities anodic process takes place mainly in the conditions of slow diffusion of electrically active particles to the anode, and at low densities (up to 10 mA/cm2) to their discharge to the atomic and lecular oxygen is preceded by a stage, which can be associated with adsorption of atoms of oxygen or with the formation of an oxide film on the surface of platinum. To detect the nature of this stage, further research is needed.Методами потенциостатической поляризации и циклической вольтамперометрии получены новые экспериментальные данные о механизме и кинетике анодных процессов на платине в расплаве CaCl2-KCl-CaO при 725–775 °С. Приведены термодинамические значения разности потенциалов вероятных суммарных реакций в диапазоне исследуемых температур. При помощи потенциостатической поляризации и циклической вольтамперометрии получены новые экспериментальные данные относительно механизма и кинетики анодного процесса на платине в расплаве CaCl2-KCl-CaO при 725–775 °С. Проведены термодинамические оценки вероятности протекания суммарных реакций при электролизе расплава на основе CaCl2-CaO с использованием неуглеродного анода. Показано, что при высоких плотностях тока анодный процесс протекает преимущественно в условиях замедленной диффузии электроактивных частиц к аноду, а при низких плотностях (до 10 мА/см2) их разряду до атомарного и молекулярного кислорода предшествует стадия, которая может быть связана с адсорбцией атомов кислорода или с образованием оксидной пленки на поверхности платины. Для установления природы этой стадии необходимы дальнейшие исследования

Anode process on platinum in CaCl2-CaO-based melt

Methods potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic processes on platinum in the molten CaCl2-KCl-CaO when 725–775 °C. Given thermodynamic values of potential difference probable total reactions in the range of the studied temperature. Using potentiostatic polarization and cyclic voltammetry obtained new data on the mechanism and kinetics of anodic process on platinum in the molten CaCl2-KCl-CaO when 725–775 °C thermodynamic assessment of the probability of occurrence total reactions during electrolysis melt on the basis of CaCl2-CaO using non-carbon anode. It is shown that at high current densities anodic process takes place mainly in the conditions of slow diffusion of electrically active particles to the anode, and at low densities (up to 10 mA/cm2) to their discharge to the atomic and lecular oxygen is preceded by a stage, which can be associated with adsorption of atoms of oxygen or with the formation of an oxide film on the surface of platinum. To detect the nature of this stage, further research is needed

Heat of Fusion of Na3AlF6 Eutectic Mixtures with CaF2 and Al2O3

The heat of fusion of eutectic mixtures of sodium cryolite with alumina and calcium fluoride was measured using differential scanning calorimetry. Melting temperatures were found to be in good agreement with literature data. The molar heat of fusion of cryolite salts and eutectic mixtures was found to be directly dependent on melting temperature. The temperature dependence coefficient is the same as that of alkali halides