Study of the kinetics of catalytic decomposition of hydrazine vapors on palladium

The decomposition rates of N2H4 on a palladium surface are studied. Experiments were conducted in a circulating unit at atmosphere pressure. The experimental method is described. The laws found for the reaction kinetics are explained by equations

Rayleigh-Taylor instability in partially ionized compressible plasmas: one fluid approach

We study the modification of the classical criterion for the linear onset and growth rate of the Rayleigh-Taylor instability (RTI) in a partially ionized (PI) plasma in the one-fluid description, considering a generalized induction equation. The governing linear equations and appropriate boundary conditions, including gravitational terms, are derived and applied to the case of the RTI in a single interface between two partially ionized plasmas. The boundary conditions lead to an equation for the frequencies in which some of them have positive complex parts, marking the appearance of the RTI. We study the ambipolar term alone first, extending the result to the full induction equation later. We find that the configuration is always unstable because of the presence of a neutral species. In the classical stability regime the growth rate is small, since the collisions prevent the neutral fluid to fully develop the RTI. For parameters in the classical instability regime the growth rate is lowered, but for the considered theoretical values of the collision frequencies and diffusion coefficients for solar prominences the differences with the compressible MHD case are small. We conclude that PI modifies some aspects of the linear RTI instability, since it takes into account that neutrals do not feel the stabilizing effect of the magnetic field. For the set of parameters representative for solar prominences, our model gives the resulting timescale comparable with observed lifetimes of RTI plumes.Comment: Accepted for publication in Astronomy & Astrophysic

NEOCLASSICAL FORMS OF CONTEMPORARY BALLET ON THE EXAMPLE OF THE WORKS OF JIRI KILIAN AND EDWARD KLUG

The article analyzes the neoclassical ballet forms of the late twentieth century, and describes the unique scenic method and stylistics of the outstanding choreographers of Europe – Jiri Kilian and Edward Klug.Their formal technical and stylistic features of their stage work are described in detail. The peculiarities of ballet neoclassic in Europe are determined. Analyzes of scientific research on ballet criticism in the field of neoclassicism and neoclassicism.Key words: neoclassicism, neoclassicism, choreography, ballet, modern ballet, stage forms, ballet of Europe, Kyiv Municipal Academy of Variety and Circus Art.

Dynamics of the vortex line density in superfluid counterflow turbulence

Describing superfluid turbulence at intermediate scales between the inter-vortex distance and the macroscale requires an acceptable equation of motion for the density of quantized vortex lines $\cal{L}$. The closure of such an equation for superfluid inhomogeneous flows requires additional inputs besides $\cal{L}$ and the normal and superfluid velocity fields. In this paper we offer a minimal closure using one additional anisotropy parameter $I_{l0}$. Using the example of counterflow superfluid turbulence we derive two coupled closure equations for the vortex line density and the anisotropy parameter $I_{l0}$ with an input of the normal and superfluid velocity fields. The various closure assumptions and the predictions of the resulting theory are tested against numerical simulations.Comment: 7 pages, 5 figure