Numerical study of the influence of relative parameters of the metamaterial structure on its mechanical behavior

In this paper, attention is focused on the influence of changes in the variable parameters of the structure of mechanical tetrachiral metamaterial on its linear elastic behavior, in particular, on its twist. The parameters characterizing the structure of the metamaterial were chosen in a relative form with respect to the unit cell size and changed independently of each other in the investigation. The results of the mechanical behavior of the tetrachiral metamaterial in the event of changes in the structural parameters were obtained. The dependencies of the rotation angle when the relative parameters change were established and analyzed. The parameters of the chiral structure, the most affecting the unusual behavior of mechanical metamaterial—a twist under uniaxial loading, were determine

On the sources of Chekhov’s journey to Sakhalin

The article was submitted on 20.06.2016.Chekhov’s awareness of Sakhalin’s problems, as well as his “stylistic misunderstandings” with those writers who had touched upon this topic before, already existed before his 1890 trip. However, both this circumstance and his preparation for the trip have not been examined in detail. It is possible to understand the idea and the structure of Sakhalin Island with the analysis of the Bibliographical List that Chekhov compiled before the trip. The analysis of the list connects the writer’s life and his choice of artistic style. According to the author, the list is a unique bibliographical model in terms of biography and aesthetics. The chronological length it covers is much more significant than the short period of time the writer spent designing it. It enables the researcher to interpret Chekhov’s Sakhalin experience more deeply and can change the connections between the items of the list and the plot of Sakhalin Island. Having studied the Report on Russian Mental Hospitals by Dr Pavel Arkhangelsky (1887), Chekhov came up with the idea of performing a similar examination of Russian prisons. This book helps us to understand the nature of Sakhalin Island and the writer’s late prosaic works better. The works studied before the trip pushed the writer to develop a new style. The author suggests that the “negative” side of Chekhov’s style might be linked with the limitations of official documentation. It is argued that Chekhov is followed his predecessors (those who wrote about hard labour and Sakhalin) in many ways. However, the author argues that Chekhov dared to disagree with them, having rejected existing stylistic forms. Analysis of the versatile and complicated style of Sakhalin Island can lead to more fruitful results if one takes into account the Report.Рассмотрены особенности понимания Чеховым проблемы Сахалина, а также его «стилистические разногласия» с авторами, высказавшимися на эту тему, сложившиеся еще до поездки 1890 г. Это обстоятельство, как и контекст подготовки к путешествию, разработано в чеховедении неполно. Такова традиция, коренящаяся в отношении к Чехову прижизненной критики. Автор ставит своей задачей понять смысл, идейную структуру «Острова Сахалина» на основе анализа «Библиографического списка», составленного Чеховым до поездки. Изучение контекста списка связывает проблемы жизненного замысла и выбора художественной манеры писателя. Чеховский список, по мнению автора, уникальная в биографическом и эстетическом отношении библиографическая модель. Хронологическое понимание его рамок гораздо шире короткого промежутка, когда он был задуман. Оно позволяет глубже интерпретировать сахалинский опыт Чехова и меняет смысл связей между пунктами списка и сюжетными моментами «Острова Сахалина». Показано также, что знакомство с «Отчетом по осмотру русских психиатрических заведений» П. А. Архангельского (1887) подтолкнуло Чехова к мысли об аналогичном исследовании тюрем. «Отчет…» углубляет понимание «Острова Сахалина» и поздней прозы Чехова: изучение таких работ привело писателя к необходимости построения нового стиля. Высказывается предположение о том, что «отрицательное» начало чеховского стиля связано с пониманием ограниченности официальной документалистики, не способной на реальный протест. Считается, что Чехов во многом наследует своим предшественникам – авторам работ о каторге и Сахалине. Однако, по мысли автора, Чехов решился на полемику с ними, отказавшись от воспроизведения существовавших стилистических форм. Описание сложного стиля «Острова Сахалина» становится более плодотворным благодаря введению в контекст «Отчета…», хронологически предшествующего всем работам чеховского списка, закрепленным в академическом чеховедении

Four-pion production

Starting from the low-energy structure derived from QCD, we extend the amplitudes for four-pion production in e+ e- annihilation and tau decays up to invariant four-pion masses of 1 GeV. Cross sections and branching ratios BR(rho^0 -> 4 pi) are compared with available data.Comment: 4 pages, 3 figures, contribution to Proc. of QCD'02, Montpellier, July 2002, misprints correcte

Analysis of stress and strain in the tetrachiral metamaterial with different kinds of unit cell connections

Metamaterials are artificially created materials whose unique properties are due to their structure rather than the chemical composition of the base material. The unit cells form the basis of a metamaterial. When creating the metamaterial, one should distinguish the methods of connecting its unit cells. The paper considers two methods of unit cell connection in a threedimensional metamaterial—joining and overlapping. Connecting the cells in the metamaterial by joining method may lead to a differently directed rotation of the rings, which will have a negative effect on the entire sample of the metamaterial. In the case of the other connection method, there is no differently directed rotation, so it would appear reasonable that creating a sample of a metamaterial by this method would achieve greater values of twist. The asymmetric deformation pattern is investigated in this work. For the two methods considered, also different results were obtained on stress distribution and strain localization in the sample under uniaxial loading. In the system of two cells in the metamaterial obtained by the joining method, an additional center of localization of deformation occurs at the junction of the two edges, which make up the tetrachiral elemen

Reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- at energies \sqrt{s}\leq 1 GeV

The cross section of reaction e^+e^-\to\pi^+\pi^-\pi^+\pi^- is calculated for energies 0.65\leq \sqrt{s}\leq1 GeV in the framework of the generalized hidden local symmetry model. The calculations are compared with the data of CMD-2 and BaBaR. It is shown that the inclusion of heavy isovector resonances \rho(1450) and \rho(1700) is necessary for reconciling calculations with the data. It is found that at \sqrt{s}\approx1 GeV the contributions of above resonances are much larger, by the factor of 30, than the \rho(770) one, and are amount to a considerable fraction \sim0.3-0.6 of the latter at \sqrt{s}\sim m_\rho.Comment: 4 pages, 3 figures; considerably reduced in siz

Production of π0ρ0\pi^0\rho^0 pair in electron-positron annihilation in the Nambu-Jona-Lasinio model

The process $e^+e^- \to \pi^0\rho$ is described in the framework of the expanded NJL model in the energy region from 0.9 GeV to 1.5 GeV. The contribution of intermediate state with vector mesons $\omega(782), \,\,\phi(1020)$, and $\omega'(1420)$, where $\omega'$ is the first radial excitation of $\omega$ - meson was taken into account. Results obtained are in satisfactory agreement with experimental data.Comment: 5 pages, 1 figure, 1 tabl

Calculation of αˉQ.E.D.\bar{\alpha}_{\rm Q.E.D.} on the Z

We perform a new, detailed calculation of the hadronic contributions to the running electromagnetic coupling, $\bar{\alpha}$, defined on the Z particle (91 GeV). We find for the hadronic contribution, including radiative corrections, 10^5\times \deltav_{\rm had.}\alpha(M_Z^2)= 2740\pm12, or, excluding the top quark contribution, 10^5\times \deltav_{\rm had.}\alpha^{(5)}(M_Z^2)= 2747\pm12. Adding the pure QED corrections we get a value for the running electromagnetic coupling of $$\bar{\alpha}_{\rm Q.E.D.}(M_Z^2)= {{1}\over{128.965\pm0.017}}.$$Comment: Version to appear in Phys. Rev. D. Plain TeX fil

Numerical study of hard-metal powder compaction

Powder compacting is a widely used process for both metallurgy and pharmaceutical production. The mathematical simulation of the powder compaction process is a promising tool for its study. The compacting of WC/Co powder by a punch in a cylindrical die is simulated in this work. The use of the Drucker-Prager Cap constitutive model is made. Results on stress distribution and volume plastic deformation during compaction are obtained. Relative density distribution in the powder compact can also be estimated from volume plastic strain. The severe influence of frictional contact between powder and die wall on the results is noted

Government regulation of small and medium entrepreneurship under the influence of value-time benchmarks

© 2015, Mediterranean Center of Social and Educational Research. All rights reserved. The article describes the role of regional infrastructure provision in small and medium entrepreneurship development in the Republic of Tatarstan. It covers and analyses efforts of republic’s government in small businesses support. Statistical data reflecting positive dynamics of measures implemented is given