Linear competition processes and generalized Polya urns with removals

A competition process is a continuous time Markov chain that can be interpreted as a system of interacting birth-and-death processes, the components of which evolve subject to a competitive interaction. This paper is devoted to the study of the long-term behaviour of such a competition process, where a component of the process increases with a linear birth rate and decreases with a rate given by a linear function of other components. A zero is an absorbing state for each component, that is, when a component becomes zero, it stays zero forever (and we say that this component becomes extinct). We show that, with probability one, eventually only a random subset of non-interacting components of the process survives. A similar result also holds for the relevant generalized Polya urn model with removals

MODIFIED HEXANIT CUTTERS FOR KNURLING OF CYLINDRICAL SHAFT SECTIONS

The possibility of using conventional cutters, in which the super-hard materials Hexanit R acts as the material for the diamond knurling of shaft sections made of steel 10, has been investigated. It is recommended to use damaged replaceable tips with super-hard material as tool blanks, which requires either re-grinding or recycling. The possibility of restoring the working properties of such cutters by regrinding is established, provided that the core of the tool is precisely located relative to the axis of rotation of the workpiece. The design of tooling in the form of a mandrel for fixing the tool on a lathe is proposed. It allows flexible clamping of the tool to the workpiece. Design and operational processing parameters are recommended for diamond knurling using tips made of superhard Hexanit-R material: knurler radius –5 mm; clamping forces – 200 N; feed – 0.05 mm/rev; workpiece rotation frequency – 630 rpm. According to the knurling results, the roughness was Ra 0.8 μm when lubricated with I-20A mineral industrial oil. An increase in the number of passes greater than four did not lead to a significant improvement in surface roughness. No signs of wear, damage to the working surface of the tool after an operating time of 40 hours were found

Features of digital socialization of primary school students in the context of different levels of Internet involvement

Nowadays, human life is greatly influenced by digitalization and informatization, which requires the reinterpretation of the matter of social formation and human development in the context of ontogenesis. From the moment of birth, a child lives in a mixed social and digital environment, which influences traditional socialization in one way or another. The researchers identify both positive and negative aspects of digital socialization of the younger generation. The authors of the present research analyzed the features of digital socialization of primary school students with different levels of Internet involvement. The experiment on the identification of Internet addiction involved 540 parents. The sample on the study of digital socialization included 316 primary school students aged 7 to 9. On the one hand, the results showed the preservation and demonstration of the content and methods of traditional socialization among younger students of all levels of Internet involvement in terms of digital socialization. This fact indicates the integration and combination of digital and traditional socialization. On the other hand, the increase in the levels of Internet involvement contributes to the replacement and transition from traditional socialization to a digital one

Підвищення ефективності токарної обробки гільз циліндрів розчинонасосів

The results of a scientific study related to improving the efficiency of turning process for mortar pump cylinder liner are presented. A literary analysis of the issue of turning optimization is carried out. Professor Larin's criterion is applied. It provides the longest cutting path, that is, the least cost of the cutting tool when machining a batch of products. Precast lathe cutter equipped with a non-grinding plate of rhombic shape of metal-ceramic hard alloy T15K6 is used as a cutting toolПриведены результаты научного исследования, посвященного повышению эффективности токарной обработки гильз цилиндров для растворонасосов. Проведен литературный анализ вопроса оптимизации точения. Применен критерий проф. Ларина. Он обеспечивает наибольший путь резания, минимальный расход режущего инструмента во время обработки резание партии изделий. В качестве режущего инструмента использовали сборный токарный проходной резец, оснащенный неперетачиваемой пластинкой ромбической формы с метаталло­керамического твердого сплава Т15К6Наведено результати наукового дослідження, пов’язаного із підвищенням ефективності токарної обробки гільз циліндрів розчинонасосів. Проведено літературний аналіз питання оптимізації точіння. Застосовано критерій проф. Ларіна. Він забезпечує найдовший шлях різання, найменші витрати різального інструмента під час обробки різанням партії виробів. В якості різального інструмента використовували збірний токарний прохідний різець, обладнаний непереточуваною пластинкою ромбічної форми з метало­керамічного твердого сплаву Т15К

MODIFIED HEXANIT CUTTERS FOR KNURLING OF CYLINDRICAL SHAFT SECTIONS

The possibility of using conventional cutters, in which the super-hard materials Hexanit R acts as the material for the diamond knurling of shaft sections made of steel 10, has been investigated. It is recommended to use damaged replaceable tips with super-hard material as tool blanks, which requires either re-grinding or recycling. The possibility of restoring the working properties of such cutters by regrinding is established, provided that the core of the tool is precisely located relative to the axis of rotation of the workpiece. The design of tooling in the form of a mandrel for fixing the tool on a lathe is proposed. It allows flexible clamping of the tool to the workpiece. Design and operational processing parameters are recommended for diamond knurling using tips made of superhard Hexanit-R material: knurler radius –5 mm; clamping forces – 200 N; feed – 0.05 mm/rev; workpiece rotation frequency – 630 rpm. According to the knurling results, the roughness was Ra 0.8 μm when lubricated with I-20A mineral industrial oil. An increase in the number of passes greater than four did not lead to a significant improvement in surface roughness. No signs of wear, damage to the working surface of the tool after an operating time of 40 hours were found

Palladium (II) Oxide Nanostructures as Promising Materials for Gas Sensors

One of the most important environment monitoring problems is the detection of oxidizing gases in the ambient air. Negative impact of noxious oxidizing gases (ozone and nitrogen oxides) on human health, sensitive vegetation, and ecosystems is very serious. For this reason, palladium (II) oxide nanostructures have been employed for oxidizing gas detection. Thin and ultrathin films of palladium (II) oxide were prepared by thermal oxidation at dry oxygen of previously formed pure palladium layers on polished poly-Al2O3, SiO2/Si (100), optical quality quartz, and amorphous carbon/KCl substrates. At ozone and nitrogen dioxide detection, PdO films prepared by oxidation at T = 870 K have demonstrated good values of sensitivity, signal stability, operation speed, and reproducibility of sensor response. In comparison with other materials, palladium (II) oxide thin and ultrathin films have some advantages at gas sensor fabrication. Firstly, for oxidizing gas detection, PdO films with p-type conductivity are more perspective than the material with n-type conductivity. Secondly, at ambient conditions, palladium (II) oxide is insoluble in water and does not react with it. These facts are favorable for the fabrication of gas detectors because they make possible to minimize the air humidity influence on PdO sensor response values. Thirdly, the synthesis procedure of PdO films is rather simple and is compatible with planar processes of microelectronic industry