On local strength of a spherical vessel with pits distributed along the equator

The effect of multiple shallow corrosion pits on the strength of a spherical vessel subjected to internal pressure is studied. The pits are considered both randomly and evenly distributed along the equator on the outer surface of the vessel. The dependencies of the stress concentration factor on the number of the pits are compared for linearly elastic and elastic-plastic material with hardening. The behavior of the vessels made of elastic and elastoplastic materials turns out to be qualitatively different. The approximation of periodic pits arrangement is discussed

Children’s Speech Development at the Age of 5–6 Years Old: A Longitudinal Study

Our longitudinal study is devoted to the study of the mutual influence of speech development and regulatory functions in children aged 5–7 years. It has been shown that the relationship between the development of regulatory functions and speech exists, but remains different for various aspects of both regulatory functions and speech. In general, it can be argued that in the case of an improvement in regulatory functions in the period of 5–6 years, the child’s performance of speech tasks improves. The data obtained allow a new approach to the development of children 5–6 years old and create complex methods for both the development of speech and regulatory functions.Представленное лонгитюдное исследование посвящено изучению взаимного влияния развития речи и регуляторных функций у детей в возрасте 5–7 лет. Показано, что связь между развитием регулятор‑ ных функций и речи существует, однако выражена в разной степени для различных аспектов как регуляторных функций, так и речи. В целом можно утверждать, что в случае улучшения регуляторных функций в период 5–6 лет у ребенка улучшается выполнение заданий на развитие речи. Полученные данные позволяют по-новому подойти к проблеме развития детей 5–6 лет и создавать комплексные методики развития речи и регуляторных функций.Работа выполнена при поддержке гранта РФФИ № 17-29-09112

Features of the cathode plasma formation at the initial stage of a nanosecond spark discharge in air

Nanosecond discharges at atmospheric pressure have a wide range of applications. The features of a nanosecond spark discharge formation strongly depend on the discharge gap geometry and the applied voltage. The present paper contains the results of near-electrode processes investigation at the initial stage of a spark discharge in air in the pin-to-plate geometry. Extra-high electron concentration in the range of $10^{19}\text{--}10^{20}\ \text{cm}^{-3}$ was obtained based on the Mach-Zehnder interferometer after breakdown near the surface of a flat cathode. It is confirmed that the discharge channel is a multitude of microchannels that close the discharge gap. Analysis of a flat electrode surface after breakdown shows that the channel binding region is a cluster of microcraters with diameter from 5 to $35\ \mu \text{m}$ . A model for the gas dynamics processes at the initial stage of a nanosecond spark discharge is proposed