Properties of Zirconia after Plasma Treatment

The influence of high-frequency plasma treatment on the properties of zirconia powder is shown in the work. The powder was produced by a plasma-chemical method. The powders had a foamy form with the size of agglomerates of 5-10 [mu]m and crystallites of 20-50 nm. The powders were treated by the pulse plasma unit with dielectric barrier discharge generator. It was shown that the plasma processing changes the acidity of water-powder suspensions from 8.1 to 4.3 pH, which signifies the powders' wettability improvement. It was revealed that more intensive mixing using ultrasound influences the acidity level, reducing it in comparison with mixing by paddle-type agitator. It was shown that these changes of surface properties have relaxation by 4% per day and extrapolation of this dependence shows that the powder will have initial properties after 400 hours storage at room conditions

Thin films flowing down inverted substrates: Three dimensional flow

We study contact line induced instabilities for a thin film of fluid under destabilizing gravitational force in three dimensional setting. In the previous work (Phys. Fluids, {\bf 22}, 052105 (2010)), we considered two dimensional flow, finding formation of surface waves whose properties within the implemented long wave model depend on a single parameter, $D=(3Ca)^{1/3}\cot\alpha$, where $Ca$ is the capillary number and $\alpha$ is the inclination angle. In the present work we consider fully 3D setting and discuss the influence of the additional dimension on stability properties of the flow. In particular, we concentrate on the coupling between the surface instability and the transverse (fingering) instabilities of the film front. We furthermore consider these instabilities in the setting where fluid viscosity varies in the transverse direction. It is found that the flow pattern strongly depends on the inclination angle and the viscosity gradient

Annihilation of vortex dipoles in an Oblate Bose-Einstein Condensate

We theoretically explore the annihilation of vortex dipoles, generated when an obstacle moves through an oblate Bose-Einstein condensate, and examine the energetics of the annihilation event. We show that the gray soliton, which results from the vortex dipole annihilation, is lower in energy than the vortex dipole. We also investigate the annihilation events numerically and observe that the annihilation occurs only when the vortex dipole overtakes the obstacle and comes closer than the coherence length. Furthermore, we find that the noise reduces the probability of annihilation events. This may explain the lack of annihilation events in experimental realizations.Comment: 8 pages and 9 figure

Three-dimensional localized coherent structures of surface turbulence. III Experiment and model validation

The paper continues a series of publications devoted to the 3D nonlinear localized coherent structures on the surface of vertically falling liquid films. The work is primarily focussed on experimental investigations. We study: (i) instabilities and transitions leading to 3D coherent structures; (ii) characteristics of these structures. Some nonstationary effects are also studied numerically. Our experimental results, as well as the results of other investigators, are in a good agreement with our theoretical and numerical predictions.Comment: 42 pages, 15 figure

Evolution of the cosmic ray anisotropy above 10^{14} eV

The amplitude and phase of the cosmic ray anisotropy are well established experimentally between 10^{11} eV and 10^{14} eV. The study of their evolution into the energy region 10^{14}-10^{16} eV can provide a significant tool for the understanding of the steepening ("knee") of the primary spectrum. In this letter we extend the EAS-TOP measurement performed at E_0 around 10^{14} eV, to higher energies by using the full data set (8 years of data taking). Results derived at about 10^{14} and 4x10^{14} eV are compared and discussed. Hints of increasing amplitude and change of phase above 10^{14} eV are reported. The significance of the observation for the understanding of cosmic ray propagation is discussed.Comment: 4 pages, 3 figures, accepted for publication on ApJ Letter

Dynamics of twisted vortex bundles and laminar propagation of the vortex front

The paper is studying the dynamics of twisted vortex bundles, which were detected in experimental investigations of superfluid turbulence in superfluid 3He-B. The analysis shows that a linear torsion oscillation of a vortex bundle is a particular case of the slow vortex mode related with the inertial wave, which was already investigated in the past in connection with observation of the Tkachenko waves in superfluid 4He and the experiments on the slow vortex relaxation in superfluid 3He-B. The paper addresses also a twisted vortex bundle terminating at a lateral wall of a container starting from the elementary case when the bundle reduces to a single vortex. The theory considers the laminar regime of the vortex-bundle evolution and investigates the Glaberson-Johnson-Ostermeier instability of the laminar regime, which is a precursor for the transition to the turbulent regime at strong twist of the bundle. The propagation and the rotation velocities of the vortex front (the segment of the vortex bundle diverging to the wall) can be found from the equations of balance for the linear and the angular momenta, and the energy. It is demonstrated that the vortex front can move with finite velocity even in the absence of mutual friction (the T = 0 limit). The theory is compared with experimental results on vortex-front propagation in superfluid 3He-B.Comment: 28 pages, 1 figure, essentially extended and revised versio

Morphometric analysis of pancytokeratin-negative neoplastic damages of the lymphatic nodes of the neck.

Patients with a diagnosis of cancer with an unknown primary localization (CUPL) are mostly referred to the category of cancer cohort with the clinical manifestation of lymph nodes enlargement. Cases of CUPL occupy 3-5% of all neoplasia of any localization, and only 20% of them have prognostically better chances as compared to other 80%. Materials and methods. The retrospective study 41 observations of the neoplastic lymph nodes in the neck without other clinical manifestations of primary tumor localization during was performed August 2016 - July 2017. The average age of patients was 47.68±16.41 years (median 46). The aim of the study was to analyze the complex of morphological, morphometric and immu­no­histochemical characteristics of Cytokeratin, Ran negative phenotypes of neoplastic lesions of lymph nodes of the neck for the improvement of diagnostic algorithms. Results. The authors have adjusted the objective parameters of nuclei of tumor cells (area, perimeter, coefficient of "roundness"), in comparison with the size of ordinary lymphocytes, the dependence of the size of the nuclei on morphological characteristics and the immunophenotype of the neoplastic damage of the lymph nodes of the neck has been analyzed

Decrease of atmospheric neutron counts observed during thunderstorms.

We report here, in brief, some results of the observation and analysis of sporadic variations of atmospheric thermal neutron flux during thunderstorms. The results obtained with unshielded scintillation neutron detectors show a prominent flux decrease correlated with meteorological precipitations after a long dry period. No observations of neutron production during thunderstorms were reported during the three-year period of data recording

The East-West method: an exposure-independent method to search for large scale anisotropies of cosmic rays

The measurement of large scale anisotropies in cosmic ray arrival directions at energies above 10^13 eV is performed through the detection of Extensive Air Showers produced by cosmic ray interactions in the atmosphere. The observed anisotropies are small, so accurate measurements require small statistical uncertainties, i.e. large datasets. These can be obtained by employing ground detector arrays with large extensions (from 10^4 to 10^9 m^2) and long operation time (up to 20 years). The control of such arrays is challenging and spurious variations in the counting rate due to instrumental effects (e.g. data taking interruptions or changes in the acceptance) and atmospheric effects (e.g. air temperature and pressure effects on EAS development) are usually present. These modulations must be corrected very precisely before performing standard anisotropy analyses, i.e. harmonic analysis of the counting rate versus local sidereal time. In this paper we discuss an alternative method to measure large scale anisotropies, the "East-West method", originally proposed by Nagashima in 1989. It is a differential method, as it is based on the analysis of the difference of the counting rates in the East and West directions. Besides explaining the principle, we present here its mathematical derivation, showing that the method is largely independent of experimental effects, that is, it does not require corrections for acceptance and/or for atmospheric effects. We explain the use of the method to derive the amplitude and phase of the anisotropy and we demonstrate its power under different conditions of detector operation