Steady-state properties of driven magnetic reconnection in 2D electron magnetohydrodynamics

We formulate a rigorous nonlinear analytical model that describes the dynamics of the diffusion (reconnection) region in driven systems in the context of electron magnetohydrodynamics (EMHD). A steady-state analysis yields allowed geometric configurations and associated reconnection rates. In addition to the well-known open X-point geometry, elongated configurations are found possible. The model predictions have been validated numerically with two-dimensional EMHD nonlinear simulations, and are in excellent agreement with previously published work.     

Multiscale coupling of compliant and rigid walls blood flow models

Numerical methods based on geometrical multiscale models of blood flows solve for averaged flow statistics on a network of vessels while providing more detailed information about fluid dynamics in a specific region of interest. In such an approach, a 3D model based on the Navier–Stokes equations posed in a domain with rigid walls is often used to describe blood flow dynamics in the refined region. While ignoring elasticity effects in 3D models is plausible in certain applications and saves computational time significantly, coupling such models with 1D flow models may result in non‐physiological phenomena in the computed solutions. Thus, the immediate coupling conditions based on continuity of normal stresses, flow rate, pressure, or a combination of thereof do not account for the inconsistency between elasticity effects in the 1D model and the non‐compliance of the 3D model. In this paper, we introduce and study an auxiliary absorbing 0D model, which is placed at the interface between 1D and 3D models. A virtual device mimics the effect of the 3D model compliance and hence reduces pressure wave reflection and instabilities caused by the inconsistency. The absorbing model is developed from basic mechanical principles. As a result, parameters of the 0D model can be designed based on hemodynamic data. We analyze the stability of the geometrical multiscale model and perform several numerical experiments to assess its computational efficiency. Copyright © 2016 John Wiley & Sons, Ltd.     

A Model of the Electronic Structure of Nanocrystalline Hydrogen

Russian Physics Journal -     

Tautomerism and Stereodynamics of Indophenols,Amidines, Their Derivatives,and Analogs: XIV. New Methods of Synthesis of Spiro-Fused Quinoxalines

A new procedure was proposed for synthesis of quinoxaline derivatives by N-alkylation of 2,6-di-tert-butyl-4-(o-R-sulfonylaminophenylimino)-2,5-cyclohexadienones and subsequent intramolecular spirocyclization. A necessary condition for the reaction to occur is high mobility of hydrogen in the N-methylene group, which is activated by electron-acceptor aroyl or two ethoxycarbonyl groups.     

Crisis of hydrodynamic drag of drops in the two-phase turbulent flow of a spray produced by a mechanical nozzle at transition reynolds Numbers

When processing experimental data for the hydrodynamics of a two-phase flow in a spray produced by a mechanical nozzle, we revealed an anomaly in the behavior of the hydrodynamic drag of drops: the drag coefficient turns out to be four to seven times lower than the previously known values. Several hypotheses are put forward to explain the anomaly. It is found that, when the gas flows around drops under highly turbulent conditions, an “early” (i.e., observed even at transition Reynolds numbers, Re>50) crisis of drag resistance of drops takes place. This new physical phenomenon allows us to account for a number of features of the two-phase flow that are observed in the experiment. Among these features is, in particular, the fact that the momentum transferred to the gas is roughly half the initial momentum of the liquid jet.     

Quasienergy pseudopotential method in the theory of interaction of a coherent electromagnetic field with matter

We formulate the quasienergy pseudopotential methods, allowing us to study the behavior of the electronic structure of a material in a coherent electromagnetic field. We show that after canonical transformation, we can look for the solution to the nonsteady-state Schrödinger equation in a basis of wave functions from extended Hubert space, substituting the quasienergy pseudopotential for the true nonsteady-state electronic potential. We prove that the familiar compensation theorem remains valid even in this case.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 33–37, February, 1992.     

Features of the change in titanium dihydride electronic structure upon deviation from stoichiometry and ordering effects in interstitial hydrogen distribution

We calculate the electronic structure of the TiH_x system with various degrees of long-range order in the hydrogen—vacancy subsystem. Pronounced deformation and damping of the electron states above and below the Fermi level is shown to occur. V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 40–48, January, 1997.     

Configuration averaging calculation of the electronic structure of alloys with arbitrary degrees of long-range order,using the lattice site distribution function

We present a new derivation of the t-site scattering operator in terms of the atomic distribution function over lattice sites. The operator path is presented in a form that avoids a double average (over the crystal potential and the t-site operator). In configuration averaging of an over-determined path operator one can introduce sampling coefficients of averages, making it possible to compute changes in symmetry during a structural order-disorder transition. These coefficients reflect the conformity of the atom-sublattice type to the characteristics of the single-electron energy spectrum of the alloy, averaged over the configurations. In this approach the limiting cases are automatically satisfied, and the secular equation reduces to the correct form.V. D. Kuznetsov Siberian Physicotechnical Institute, Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 57–61, October, 1995.