Generalization of the Grad method in plasma physics

The Grad method is generalized based on the Bogolyubov idea of the functional hypothesis for states at the end of relaxation processes in a system. The Grad problem (i.e., description of the Maxwell relaxation) for a completely ionized spatially uniform two-component electron-ion plasma is investigated using the Landau kinetic equation. The component distribution functions and time evolution equations for parameters describing the state of a system are calculated, and corrections are obtained to the known results in a perturbation theory in a small electron-to-ion mass ratio.Comment: 10 pages, 2 table

TYC 1031 01262 1: The First Known Galactic Eclipsing Binary with a Type II Cepheid Component

We present the discovery and CCD observations of the first eclipsing binary with a Type II Cepheid component in our Galaxy. The pulsation and orbital periods are found to be 4.1523 and 51.38 days, respectively, i.e. this variable is a system with the shortest orbital period among known Cepheid binaries. Pulsations dominate the brightness variations. The eclipses are assumed to be partial. The EB-subtype eclipsing light curve permits to believe that the binary's components are non-spherical.Comment: 3 pages, 3 figures, accepted to MNRAS Letter

On relaxation phenomena in a two-component plasma

The relaxation of temperatures and velocities of the components of a quasi-equilibrium two-component homogeneous completely ionized plasma is investigated on the basis of a generalization of the Chapman-Enskog method applied to the Landau kinetic equation. The generalization is based on the functional hypothesis in order to account for the presence of kinetic modes of the system. In the approximation of a small difference of the component temperatures and velocities, it is shown that relaxation really exists (the relaxation rates are positive). The proof is based on the arguments that are valid for an arbitrary two-component system. The equations describing the temperature and velocity kinetic modes of the system are investigated in a perturbation theory in the square root of the small electron-to-ion mass ratio. The equations of each order of this perturbation theory are solved with the help of the Sonine polynomial expansion. Corrections to the known Landau results related to the distribution functions of the plasma and relaxation rates are obtained. The hydrodynamic theory based on these results should take into account a violation of local equilibrium in the presence of relaxation processes.Comment: 18 page

Thermal regimes of HTS cylinders operating in devices for fault current limitation

We reveal obstacles related to the application of HTS cylinders in current limiting devices based on the superconducting - normal state transition. It is shown that, at the critical current density achieved presently in bulk materials, and especially in BSCCO-2212, the required thickness of the cylinder wall in a full-scale inductive device achieves several centimeters. A simple mathematical model of the operation of an inductive fault current limiter (FCL) is used to show that such cylinders cannot be cooled in admissible time after a fault clearing and, hence, the inductive FCLs and current-limiting transformers employing BSCCO cylinders do not return to the normal operation in the time required. For the recovery even with a non-current pause in the circuit, the cylinders are needed with the critical current density by an order higher than the existed ones.Comment: 15 pages, 5 figure

THE LEADING–ORDER HYDRODYNAMICS OF THE LANDAU-VLASOV KINECTIC EQUATION WITH THE NONLOCAL COLLISION INTEGRAL

This paper is devoted to the hydrodynamics of a one-component gas with small potential interaction. The basis of investigation is the kinetic equation in case of small potential interaction which contains general nonlocal collision integral [1] and describes arbitrary non-uniform states. In the local approximation this equation coincides with the well-known Landau–Vlasov kinetic equation. In hydrodynamics the system is supposed to be weakly non-uniform

The leading-order hydrodynamics of the Landau-Vlasov kinectic equation with the nonlocal collision integral

This paper is devoted to the hydrodynamics of a one-component gas with small potential interaction. The basis of investigation is the kinetic equation in case of small potential interaction which contains general nonlocal collision integral [1] and describes arbitrary non-uniform states. In the local approximation this equation coincides with the well-known Landau–Vlasov kinetic equation. In hydrodynamics the system is supposed to be weakly non-uniform

Influence of the enterosorbent on quality of eggs

In this article research the influence of natural montmorillonite containing sorbent used as a mineral supplement in animal feed in an amount of 30 g per 1 kg of sorbent feed on commercial quality table eggs at his dacha hens-layers. Found that feeding hens’ mineral feed additive reduces the toxic chemical elements in a chicken egg. It was found that the weight of the eggs in the experimental group compared to the control group, was significantly increased by 3,5% (p <0,05) after the completion of feeding the mineral sorbent. Despite the fact that in the control group, egg weight did not change and remained virtually unchange

An improved design of an inductive fault current limiter based on a superconducting cylinder

The paper deals with basic designs of a fault current limiter of the transformer type which differ each other by the mutual location of a primary winding and a superconducting short-circuited cylinder. Theoretical study of the main parameters of the different designs is performed in the framework of the critical state model and shows that the most effective is a design in which the primary winding is divided to two sections with equal turn numbers. The sections are placed inside and outside of the cylinder and connected in series. Such arrangement of the windings leads to a substantial reduction of AC losses in the superconducting cylinder, an increase of the activation current and a decrease of the inductive reactance in the normal regime of a protected circuit. The experimental results obtained on the laboratory model with a BSSCO cylinder confirm the theoretical predictions.Comment: 17 pages, 9 figure

The massive star population of the Virgo Cluster galaxy NGC 4535

We analyzed the massive star population of the Virgo Cluster galaxy NGC 4535 using archival Hubble Space Telescope Wide Field Planetary Camera 2 images in filters F555W and F814W, equivalent to Johnson V and Kron-Cousins I. We performed high precision point spread function fitting photometry of 24353 sources including 3762 candidate blue supergiants, 841 candidate yellow supergiants and 370 candidate red supergiants. We estimated the ratio of blue to red supergiants as a decreasing function of galactocentric radius. Using Modules for Experiments in Stellar Astrophysics isochrones at solar metallicity, we defined the luminosity function and estimated the star formation history of the galaxy over the last 60 Myrs. We conducted a variability search in the V and I filters using three variability indexes: the median absolute deviation, the interquartile range and the inverse von-Neumann ratio. This analysis yielded 120 new variable candidates with absolute magnitudes ranging from M$_{V}$ = $-$4 to $-$11 mag. We used the MESA evolutionary tracks at solar metallicity, to classify the variables based on their absolute magnitude and their position on the color-magnitude diagram. Among the new candidate variable sources are eight candidate variable red supergiants, three candidate variable yellow supergiants and one candidate luminous blue variable, which we suggest for follow-up observations.Comment: Accepted by A&A, 7 pages, 7 Tables, 53 figure