Synthesis and characterisation of nanocrystalline ZrN PVD coatings on AISI 430 stainless steel

The nanocrystalline films of zirconium nitride have been synthesized using ion-plasma vacuum-arc deposition technique in combination with high-frequency discharge (RF) on AISI 430 stainless steel at 150oC. Structure examinations X-ray fluorescent analysis (XRF), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) with microanalysis (EDS), and transmission electron microscopy (TEM), nanoidentation method – were performed to study phase and chemical composition, surface morphology, microstructure and nanohardness of coatings. The developed technology provided low-temperature coatings synthesis, minimized discharge breakdown decreasing formation of macroparticles (MPs) and allowed to deposit ZrN coatings with hardness variation 26.6…31.5 GPa. It was revealed that ZrN single-phase coatings of cubic modification with finecrystalline grains of 20 nm in size were formed

Intellectual Control System of Processing on CNC Machines

Scientific and technical progress makes great demands for quality of engineering production. The priority is to ensure metalworking equipment with required dimensional accuracy during the entire period of operation at minimum manufacturing costs. In article considered the problem of increasing of accuracy of processing products on CNC. The authors offers a solution to the problem by providing compensating adjustment in the trajectory of the cutting tool and machining mode. The necessity of creation of mathematical models of processes behavior in an automated technological system operations (OATS). Based on the research, authors have proposed a generalized diagram of diagnosis and input operative correction and approximate mathematical models of individual processes of diagnosis

Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets

The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment

Zinc oxide-nickel cermet selective coatings obtained by sequential electrodeposition

The investigation of pulse electrodepositing modes influence on crystal structure, morphology and optical properties of ZnO has revealed the conditions in which quasi-one-dimensional (1D) ZnO nanorod arrays are formed as separate nanorods. Due to a sufficiently high resistance of zinc oxide, the electrodeposition of nickel on the fluorine doped tin oxide (FTO)/ZnO surfaces carried out in space between the ZnO nanorods. An incomplete filling of the gaps between nanorods by the nickel nanoparticles through subsequent Ni electrodeposition ensured the creation of ZnO–Ni graded cermets. The cermets, in which electrochemical filling of the spaces between ZnO nanorods by Ni, was performed in the pulse mode. It provided higher absorption of visible and near IR light. It was shown that the manufactured ZnO–Ni graded cermets have high light absorption combined with comparatively low thermal losses, so these cermets are promising cheap and affordable selective coatings for solar heat collectors

COVID-19 and BCG vaccine: is there a link?

The spread of the novel coronavirus infection (COVID-19) makes the search for new approaches to prevent the infection of great importance. As one of the relevant approaches, the vaccination of risk groups with BCG vaccine has recently been suggested. BCG (Mycobacterium bovis, Bacillus Calmette–Guérin) is a live vaccine for tuberculosis, which is used in many countries with a high tuberculosis prevalence and helps preventing childhood tuberculosis, primarily, military disease and tuberculosis meningitis. Whether BCG may be used to increase the protection against COVID-19 is currently a question of debates. The review considers scientific background underlying possible impact of BCG in increased protection against COVID-19. BCG is able of inducing the heterologous and trained immunity, and its capacity to stimulate antiviral immune response has been demonstrated in experimental animals and humans. Our comparison of the dynamics of COVID-19 morbidity and mortality in countries with different BCG vaccination policies has demonstrated a milder course of COVID-19 (i.e., a slower increase in disease cases and mortality) in countries where BCG vaccination is mandatory for all children. However, an association between BCG vaccination and a milder COVID-19 course is not obligatory direct. Other factors that may affect the association, such as the level of virus testing, the rigidity and the speed of quarantine implementation and others are discussed. An important argument against a role of BCG in the protection against COVID-19 is that BCG is given in childhood and may hardly induce long-lasting immunity. Because mandatory BCG vaccination is implemented in countries with high TB burden and because in these countries latent tuberculosis infection is widely spread, we suggest a hypothesis that latent tuberculosis infection may contribute to the maintenance of heterologous/trained antiviral immunity in countries with mandatory BCG vaccination. Four countries have recently initiated clinical trials to investigate whether BCG vaccination can increase the level of protection against COVID-19 in risk groups. The results of these studies, as well as COVID-19 epidemiological modeling will help understanding the impact of BCG in the level of the protection against COVID-19. Performing analogous clinical trials in Russia seems appropriate and scientifically sound

Development and Application of Methods of Internal Inspection of District Heating Networks

The reliability of heat supply in cities is largely determined by the actual condition of pipelines, for example, corrosive and erosive wear. Comparative analysis of methodological approaches to assessing the technical condition of district heating networks shows that the most innovative and effective approach is internal pipe inspection using non-destructive magnetic testing. The article presents the results of research tests of the method in the context of its use for maintenance and retrofitting of the heating infrastructure in Yekaterinburg, a Russian city with a complex topology of utility networks and extremely uneven tear and wear on some sections of the networks. The authors describe the technical and economic peculiarities of using internal pipe inspection methods at various stages of testing and formulate qualitative and quantitative criteria for assessing the effectiveness of the method being presented. Recommendations have been suggested for the optimum application of the method by heat network operators, especially those operating and servicing district heating systems.The work was supported by Act 211 of the Government of the Russian Federation, contract № 02.A03.21.0006

The problems of genetic support of dividing the black kite (Milvus migrans) into subspecies

The black kite Milvus migrans is a common bird of prey demonstrating remarkable ecological plasticity. It inhabits a variety of habitats and is an increasingly synanthropic species. The black kite is widespread in Eurasia, Africa, Australia and adjacent islands. Palearctic kites migrate to Africa, India and China in winter, but kites of Africa and Australia are partly sedentary and partly seasonal migrants. The wide range and high mobility are the reasons of a complex population structure of the black kite. Commonly five to seven M. migrans subspecies are distinguished, each of which is widespread over extensive areas and has more or less an apparent phenotype. Recently, studies of genetic differences between black kite populations started to emerge. On the grounds of earlier studies of mitochondrial and nuclear genes of this species, we check whether there is a genetic support for separation of the black kite subspecies. Recent studies of some mitochondrial loci substantiate the recognition of at least the European (M. m. migrans), Asian (M. m. lineatus and M. m. govinda), African (M. m. aegyptius and M. m. parasitus), and Australian (M. m. affinis) black kite subspecies. Furthermore, the mitochondrial haplotype difference suggests that the African yellow-billed kite, including M. m. aegyptius and M. m. parasitus, should be a separate species as already proposed, or even two separate species

The Study of the Properties of Uranium Dioxide Pellets Depending on the Parameters of Pressing and Sintering

The paper presents dilatometric research of uranium dioxide pellets, fabricated by compaction at different pressure values. Temperature observed at sintering start is determined and it is pointed out that this temperature doesn’t depend on compaction pressure. Keywords: uranium dioxide, compaction, sintering, dilatometry, shrink curves, geometric density, pycnometric density

Механизмы обеспечения достоверности и надежности передачи данных по радиоканалу с использованием эстафетной технологии и их реализация на трансиверах с модуляцией LoRa

The article is devoted to a detailed description of the algorithms of the operation of the relay-race data transmission system over a radio channel, which ensure high reliability of transporting the results of monitoring the operation of extended objects to the central control panel. The feature of the system is operation at a low power level of transmitters, energy efficiency, which ensures a long-term operation without maintenance, the ability to replace failed elements quickly without stopping the entire system, mobility —  quick installation and start-up of the system. Energy efficiency and operation of the radio channel with a low transmitter power level is ensured by the use of SX 1276 (LoRa) transceivers. The accuracy and reliability of data transmission is ensured by original algorithms, which are described in the paper. In the relay data transmission system, it is possible to use up to 255 relay nodes with their installation at a distance of up to 4 km from each other. Two options of building a system with relay-race transmission have been developed: a system with a simple handover, a system with transmission «Through one». The second option provides more reliable data transfer and higher probability of uptime. With the number of relay nodes equal to 50, the probability of failure-free operation of a simple system is 0.268, and for the system with «Through one» transmission is 0.985. Luchinin A. S., Malygin I. V., Starikov S. I., Chechetkin V. A., Shegal A. A., Belkov S. A. Mechanisms of ensuring the accuracy and reliability of data transmission over a radio channel using relay technology and their implementation on transceivers with LoRa modulation. Ural Radio Engineering Journal. 2023;7(2):191–217. (In Russ.) DOI: 10.15826/urej.2023.7.2.006.Статья посвящена детальному описанию алгоритмов работы системы эстафетной передачи данных по радиоканалу, обеспечивающих высокую надежность транспортировки результатов наблюдения за работой протяженных объектов на центральный пульт контроля. Особенностью системы является работа на малом уровне мощности передатчиков, экономичность по потреблению электроэнергии, обеспечивающая длительную работу без обслуживания, возможность быстрой замены вышедших из строя элементов без остановки всей системы, мобильность —  быстрая установка и запуск системы. Экономичность энергопотребления и работа радиоканала с низким уровнем мощности передатчиков обеспечиваются применением трансиверов SX 1276 (LoRa). Достоверность и надежность передачи данных обеспечивается оригинальными алгоритмами, описание которых приводится в статье. В системе эстафетной передачи данных возможно использование до 255 узлов ретрансляции с установкой их на расстоянии до 4 км друг от друга. Разработаны два варианта построения системы с эстафетной передачей: система с простой эстафетной передачей и система с передачей «через одного». Второй вариант обеспечивает более надежную передачу данных и более высокую вероятность безотказной работы. При числе узлов ретрансляции, равном 50, вероятность безотказной работы простой системы составляет 0,268, а системы с передачей «через одного» —  0,985. Лучинин А. С., Малыгин И. В., Стариков С. И., Чечеткин В. А., Шегал А. А., Бельков С. А. Механизмы обеспечения достоверности и надежности передачи данных по радиоканалу с использованием эстафетной технологии и их реализация на трансиверах с модуляцией LoRa. Ural Radio Engineering Journal. 2023;7(2):191–217. DOI: 10.15826/urej.2023.7.2.006