Conductivity and permittivity of dispersed systems with penetrable particle-host interphase

A model for the study of the effective quasistatic conductivity and permittivity of dispersed systems with particle-host interphase, within which many-particle polarization and correlation contributions are effectively incorporated, is presented. The structure of the system's components, including the interphase, is taken into account through modelling their low-frequency complex permittivity profiles. The model describes, among other things, a percolation-type behavior of the effective conductivity, accompanied by a considerable increase in the real part of the effective complex permittivity. The percolation threshold location is determined mainly by the thickness of the interphase. The "double" percolation effect is predicted. The results are contrasted with experiment.Comment: 10 pages, 10 figure

Simulation of population’s reproductive behaviour patterns within an agent-oriented regional model

The study focuses on the research on how the unevenness of demographic transition affects the social and demographic characteristics and their dynamics of a region’s population. The research was conducted by means of computerized experiments (simulations) set within an original agent-oriented model. The study features the structure of the model represented by an artificial society, with its members (agents) being attributed their personal characteristics in such a way that they would imitate the gender and age of the region’s population. The agents are divided into two groups which differ in their reproductive strategy. Agents from Group 1 adhere to the traditional strategy characterized by a high birth rate, while the agents from Group 2 follow the modern strategy resulting in a markedly low birth rate. With the application of probabilistic mechanisms, the natural birth-death processes are imitated within the model. The extinction of agents occurs in accordance with the death rates adjusted for age and gender but remaining the same for the whole population. In the model, the appearance of new agents (birth of children) results from the choice made by reproductive-aged female agents, and their choice is influenced by the subjective traits determined by their group. The age and social structure of the regional population are generally formed as a result of the aggregation of particular agents’ activity. The model has been applied in a range of experiments on forecasting the number and structure of the population in an assumed region. The results showed that despite the apparent simplification of the reality, the developed agent-oriented model correctly represents both the initial condition of the regional population including the gender, age and social structure and the dynamics of the population’s basic characteristics.The research has been supported by the Russian Science Foundation (Project № 14-18-01968)

Mechanism of phase transitions and the electronic density of states in (La,Sm)FeAsO1−x_{1-x}Fx_x from ab initio calculations

The structure and electronic density of states in layered LnFeAsO$_{1-x}$F$_x$ (Ln=La,Sm; $x$=0.0, 0.125, 0.25) are investigated using density functional theory. For the $x$=0.0 system we predict a complex potential energy surface, formed by close-lying single-well and double-well potentials, which gives rise to the tetragonal-to-orthorhombic structural transition, appearance of the magnetic order, and an anomaly in the specific heat capacity observed experimentally at temperatures below $\sim$140--160 K. We propose a mechanism for these transitions and suggest that these phenomena are generic to all compounds containing FeAs layers. For $x>$0.0 we demonstrate that transition temperatures to the superconducting state and their dependence on $x$ correlate well with the calculated magnitude of the electronic density of states at the Fermi energy.Comment: 4 pages, 3 figures, 1 tabl

Політика держави у формуванні культури громадянськогог суспільства: вибір стратегії.

Сушко, А.І. Політика держави у формуванні культури громадянськогог суспільства: вибір стратегії. / А.І. Сушко // Актуальні проблеми політики : зб. наук. пр. / редкол. : С. В. Ківалов (голов. ред.), Л. І. Кормич (заст. голов. ред.), Ю. П. Аленін [та ін.] ; МОНмолодьспорт України, НУ ОЮА. – Одеса : Фенікс, 2011. – Вип. 43. С. 10 - 15.The world tendencies of modern states cultural policy forming are illu- minated and analysed in the article. The process of modernization of public policy of Ukraine in the fi eld of culture is comprehended

Особливості розв’язання зворотної задачі імпедансної томографії методом зон провідності

The comparison of the iterative process convergence for the EIT inverse problem solving by classical Newton-Raphson method, regularization method by A. Tyhonov and asymmetric current source connection to zones phantom is carried out. Ill-conditionality of the derivatives matrix is shown. It leads to very big errors. The regularization method by A. Tyhonov gives satisfactory results at any position of zones phantom relatively current source connection. Chosen methods for the inverse problem are programmed easy and are convenient in practice, because of their usage with zones conductivities method.Проведено сравнение сходимости итерационной процедуры решения обратной задачи импедансной томографии классическим методом Ньютона – Рафсона, методом регуляризации по А.Н. Тихонову и методом асимметричного подключения источника тока к зонному фантому. Показано плохую обусловленность матрицы производных, что приводит к непозволительно высоким погрешностям. При любом положении зонного фантома относительно источника тока регуляризация по Тихонову даёт удовлетворительный результат. Избранные для решения обратной задачи методы легко программируются и удобны на практике благодаря их использованию совместно с методом зон проводимости.Проведено порівняння сходимості ітераційної процедури розв’язання зворотної задачі імпедансної томографії класичним методом Ньютона-Рафсона, методом регуляризації за А.Н. Тихоновим та методом асиметричного підключення джерела струму до зонного фантома. Показано погану зумовленість матриці похідних, що приводить до дуже великих похибок. При довільному розташуванні зонного фантома відносно джерела струму регуляризація за Тихоновим дає задовільні результати. Обрані для розв’язання зворотної задачі методи легко програмуються і зручні на практиці завдяки їх використанню разом із методом зон провідності

New design of cutters for coal mining machines

The author designs an up-to-date rock cutter for mining machines and presents a matrix to determine its service life depending on the strength of the rock being broken. The dependence of the cutter service life on the strength of the rock being broken is proved. Advanced designs of rock cutters by the leading companies are described. The author develops an original design of a rock cutter which provides greater cutting surface, increased strength and prolonged service life. Pilot samples of the cutters ready to the test run are presented