Poplygin V.V.,Perm State University
Neftyanoe Khozyaistvo - Oil Industry | Year: 2011
The dynamics of the wells productivity In the Bobrlkovskiy deposits of the North of the Perm region layers is evaluated in case of their operation with the driving in pressures lower than saturation pressure. Dependences for evaluating the Indices which characterize a change In the productivity of the wells are obtained.
Grischenko A.V.,Perm State University
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2013
One cyclostome, one ctenostome and nine cheilostome bryozoan species, collected during Cruise 51 of the R.V. Akademik M.A. Lavrentyev in the northern part of the Sea of Japan at five stations, ranging from 455 to 2481. m in depth, comprise the first records of bathyal bryozoans from this sea. Among these are six species newly recorded from the bathyal zone, and eight species displaying their deepest records. Two bryozoans, Bugula pacifica nana and Scrupocellaria scabra var. praenulata forma orientalis, are elevated to full species status, respectively Bugula nana and Scrupocellaria orientalis. The records of Scrupocellaria orientalis, Microporina okadai and Klugeflustra kishikaensis are the first for the Sea of Japan, with Eucratea arctica recorded for the first time from the northern Pacific. The predominance of erect rooted, branching and foliaceous colonies is strongly correlated with the distribution of soft sediments in the collecting area, possibly accounting for the low overall species diversity and abundance. © 2012 Elsevier Ltd.
Tsiberkin K.,Perm State University
European Physical Journal B | Year: 2016
The collective spin excitations in the unbounded 2D paramagnetic system with dipole interactions are studied. The model Hamiltonian includes Zeeman energy and dipole interaction energy, while the exchange vanishes. The system is placed into a constant uniform magnetic field which is orthogonal to the lattice plane. It provides the equilibrium state with spin ordering along the field direction, and the saturation is reached at zero temperature. We consider the deviations of spin magnetic moments from its equilibrium position along the external field. The Holstein-Primakoff representation is applied to spin operators in low-temperature approximation. When the interaction between the spin waves is negligible and only two-magnon terms are taken into account, the Hamiltonian diagonalisation is possible. We obtain the dispersion relation for spin waves in the square and hexagonal honeycomb lattice. Bose-Einstein statistics determine the average number of spin deviations, and total system magnetization. The lattice structure does not influence on magnetization at the long-wavelength limit. The dependencies of the relative magnetization and longitudinal susceptibility on temperature and external field intensity are found. The internal energy and specific heat of the Bose gas of spin waves are calculated. The collective spin excitations play a significant role in the properties of the paramagnetic system at low temperature and strong external magnetic field. © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Soize C.,CNRS Multiscale Modelling and Simulation Laboratory |
Poloskov I.E.,Perm State University
Computers and Mathematics with Applications | Year: 2012
Abstract The paper is devoted to the computational time-domain formulation of linear viscoelastic systems submitted to a nonstationary stochastic excitation and in the presence of model uncertainties which are modeled in the framework of the probability theory. The objective is to introduce and to develop an adapted and complete formulation of such a problem in the context of computational mechanics. A reduced-order model in the time domain with stochastic excitation is derived from the computational model. For the reduced-order model, the stochastic modeling of both computational model-parameter uncertainties and modeling errors is carried out using the nonparametric probabilistic approach and the random matrix theory. We present a new formulation of model uncertainties to construct the random operators for viscoelastic media. We then obtained a linear Stochastic Integro-Differential Equation (SIDE) with random operators and with a stochastic nonhomogeneous part (stochastic excitation). A time discretization of this SIDE is proposed. In a first step, the SIDE is transformed to a linear Itô Stochastic Differential Equation (ISDE) with random operators. Then the ISDE is discretized using an extension of the Störmer-Verlet scheme which is a particularly well adapted algorithm for long-time good behavior of the numerical solution. Finally, for the stochastic solver and statistical estimations of the random responses, we propose to use the Monte Carlo simulation for Gaussian and non-Gaussian excitations. © 2012 Elsevier Ltd. All rights reserved.
Kozlov N.,Perm State University
Acta Astronautica | Year: 2015
Dynamics of a viscous fluid is investigated theoretically in an annulus with the free inner cylinder under conditions of rotation in an external inertial or gravitational field. The two-dimensional formulation is used, corresponding to two long coaxial cylinders. The inner cylinder is free and occupies a steady position on the rotation axis under the action of the centrifugal force due to the fact that it is lighter than surrounding fluid. The action of external force, oriented perpendicular to the rotation axis, induces inertial circular, of the tidal-like type, oscillations of the inner cylinder (core). As a result of the oscillations, the core is brought into rotation relative to the cavity (the outer cylinder) on the background of a steady streaming in the annulus. The mechanism of this differential rotation consists in the generation of an average mass force, of the azimuthal direction, in the oscillating viscous boundary layers on the walls of the core and the cavity. © 2015 IAA. Published by Elsevier Ltd. All rights reserved.