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  • A new type of vortex-free flows of helium II in a rotating cylinder

    Within the framework of the two-fluid Landau theory, flows into helium II inside a rotating cylinder are investigated. Special attention is paid to the analysis of excitation by centrifugal forces of counter-current (by super-fluid and normal components) flows. In the approximation of incompressible fluid, an analytical solution of the equations of motion, vortex-free for both components is obtained. The tangential velocities for it are the same as those of a rotating solid body, with the normal and superfluid components moving in opposite directions, with different angular velocities. It's resulting vorticity is compensated by a spiraled counter-current radical movements. Such solution has no axial symmetry and has a tangential gap along the radius. Despite its instability, it is of some interest. First, it can be corrected by stabilizing deformations. In addition, it shows the paths of loss of stability of high-symmetric States. In particular, in our opinion, this type of disturbance are intermediate flow from Landau (superfluid component is at rest) one to the rotation of the Feynman type (in the superfluid part of a system of vortices).

    Keywords: helium II, rotating cylinder, two-fluid theory, counter-current flows, centrifugal forces, vorticity compensation

  • Ultradispersive copper powder production condition selection based on electrocrystallization kinetics research

    Effect of water-soluble polymers additive and surface treatment on particle size distribution are shown in this article.

    Keywords: electrolytic copper powder, water-soluble polymer, polyvinylpyrrolidone, polyacrilamide, electropolishing, atomic force microscopy