Identification of new cataclysmic variables in the 1RXS and USNO-B1.0 catalogs

As a result of applying the original optical variability search method on publicly available data, we have found eight new cataclysmic variables and two possible Optically Violent Variable quasars among the previously unidentified X-ray sources in the ROSAT catalog. We describe the search method and present the characteristics of the newly identified variable stars. The obtained results demonstrate the large potential of the concept of Virtual Observatory for identifying new objects of astrophysical interest.Comment: 16 pages, 11 figures, 2 tables; submitted to Astronomy Letter

New Cataclysmic Variable 1RXS J073346.0+261933 in Gemini

In course of the search for the optical identifications associated with ROSAT X-ray sources we have found a highly variable object with the very unusual long-term behavior, color indices and high X-ray-to-optical flux ratio. We report the archival photometric light curve from the Catalina Sky Survey, optical spectroscopy from RTT150 and time-resolved photometry from Astrotel-Caucasus telescope. The object appears to be the magnetic cataclysmic variable (polar) with orbital period of P=3.20 hr.Comment: 8 pages, 5 figures. Submitted to Astronomy Letter

LC nanocomposites: induced optical singularities, managed nano/micro structure, and electrical conductivity

Microstructure, phase transitions, electrical conductivity, and optical and electrooptical properties of multiwalled carbon nanotubes (NTs), dispersed in the cholesteric liquid crystal (cholesteryl oleyl carbonate, COC), nematic 5CB and their mixtures, were studied in the temperature range between 255 K and 363 K. The relative concentration X=COC/(COC+5CB)was varied within 0.0-1.0. The concentration $C_p$ of NTs was varied within 0.01-5% wt. The value of X affected agglomeration and stability of NTs inside COC+5CB. High-quality dispersion, exfoliation, and stabilization of the NTs were observed in COC solvent ("good" solvent). From the other side, the aggregation of NTs was very pronounced in nematic 5CB solvent ("bad" solvent). The dispersing quality of solvent influenced the percolation concentration $C_p$, corresponding to transition between the low conductive and high conductive states: e.g., percolation was observed at $C_p=1$ and $C_p=0.1$ for pure COC and 5CB, respectively. The effects of thermal pre-history on the heating-cooling hysteretic behavior of electrical conductivity were studied. The mechanism of dispersion of NTs in COC+5CB mixtures is discussed. Utilization of the mixtures of "good" and "bad" solvents allowed fine regulation of the dispersion, stability and electrical conductivity of LC+NTs composites. The mixtures of COC and 5CB were found to be promising for application as functional media with controllable useful chiral and electrophysical properties.Comment: 10 pages, 9 figure

Research of the rotor end winding ventilation ducts effect on the thermal state of enclosed synchronous generator

В данной статье рассматривается влияние вентиляционных каналов в торцевых частях обмотки возбуждения генератора на общий среднеобъемный перегрев обмотки возбуждения относительно поступающего в межполюсное пространство воздуха с помощью численного моделирования в пакете ANSYS.In this paper the number and size effect of the end rotor winding ventilation ducts in synchronous generator SG-60 on volume average winding temperature rise over the inflow air using numerical modeling approach in ANSYS is considered

Calculation of the spatial equivalent scheme of the magnetic circuit of the asynchronous motor with an asymmetric magnetic core

Картина магнитного поля в асинхронном двигателе с асимметричным магнитопроводом претерпевает значительные изменения. С увеличением пазового рассеяния возникает осевая составляющая магнитного потока. В данном докладе рассчитывается магнитная цепь с целью оценки величины осевой составляющей по отношению к основному магнитному полю и меры борьбы с ним.The picture of the magnetic field in the induction motor with an asymmetric magnetic core is undergoing significant changes. With increasing scattering occurs grooved axial component of the magnetic flux. The report calculated the magnetic circuit in order to assess the magnitude of the axial component relative to the main magnetic field and measures to combat it

Calculation of the inductive resistance of the phase of the anker winding of the sup-exciter of the combined multifunctional brushless exciter

In this paper, the picture of the magnetic field of scattering and mutual induction of the anker winding of the sup-exciter for the three types of configuration of the tooth-groove layer is considered.. The inductive resistance of scattering and mutual induction for the entire phase is calculated.В данной статье рассмотрена картина магнитного поля рассеяния и взаимоиндукции якорной обмотки подвозбудителя для трёх типов конфигурации зубцово-пазового слоя. Рассчитано индуктивное сопротивление рассеяния и взаимоиндукции для всей фазы

Optical polarization observations with the MASTER robotic net

We present results of optical polarization observations performed with the MASTER robotic net for three types of objects: gamma-ray bursts, supernovae, and blazars. For the Swift gamma-ray bursts GRB100906A, GRB110422A, GRB121011A, polarization observations were obtained during very early stages of optical emission. For GRB100906A it was the first prompt optical polarization observation in the world. Photometry in polarizers is presented for Type Ia Supernova 2012bh during 20 days, starting on March 27, 2012. We find that the linear polarization of SN 2012bh at the early stage of the envelope expansion was less than 3%. Polarization measurements for the blazars OC 457, 3C 454.3, QSO B1215+303, 87GB 165943.2+395846 at single nights are presented. We infer the degree of the linear polarization and polarization angle. The blazars OC 457 and 3C 454.3 were observed during their periods of activity. The results show that MASTER is able to measure substantially polarized light; at the same time it is not suitable for determining weak polarization (less than 5%) of dim objects (fainter than 16$^m$). Polarimetric observations of the optical emission from gamma-ray bursts and supernovae are necessary to investigate the nature of these transient objects.Comment: 31 pages, 12 figures, 4 tables; Exposure times in Table 2 have been correcte