Magnetic field topology of the RS CVn star II Pegasi

The dynamo processes in cool active stars generate complex magnetic fields responsible for prominent surface stellar activity and variability at different time scales. For a small number of cool stars magnetic field topologies were reconstructed from the time series of spectropolarimetric observations using the Zeeman Doppler imaging (ZDI) method. In this study we follow a long-term evolution of the magnetic field topology of the RS CVn binary star II Peg. We collected high-resolution circular polarisation observations of II Peg using the SOFIN spectropolarimeter at the Nordic Optical Telescope. These data cover 12 epochs spread over 7 years. A multi-line diagnostic technique in combination with a new ZDI code is applied to interpret these observations. Magnetic inversions using these data reveals evolving magnetic fields with typical local strengths of 0.5-1.0 kG and complex topologies. Despite using a self-consistent magnetic and temperature mapping technique, we do not find a clear correlation between magnetic and temperature features in the ZDI maps. Neither do we confirm the presence of persistent azimuthal field rings found in other RS CVn stars. Reconstruction of the magnetic field topology of II Peg reveals significant evolution of both the surface magnetic field structure and the extended magnetospheric field geometry. From 2004 to 2010 the total field energy drastically declined and the field became less axisymmetric. This also coincided with the transition from predominantly poloidal to mainly toroidal field topology. A qualitative comparison of the ZDI maps of II Peg with the prediction of dynamo theory suggests that the magnetic field in this star is produced mainly by the turbulent alpha^2 dynamo rather than the solar alphaOmega dynamo. Our results do not show a clear active longitude system, nor is there an evidence of the presence of an azimuthal dynamo wave.Comment: 20 pages, 10 figures; accepted for publication in Astronomy & Astrophysic

Magnetic Doppler imaging of the roAp star HD 24712

We present the first magnetic Doppler images of a rapidly oscillating Ap (roAp) star. We deduce information about magnetic field geometry and abundance distributions of a number of chemical elements on the surface of the hitherto best studied roAp star, HD 24712, using the magnetic Doppler imaging (MDI) code, INVERS10, which allows us to reconstruct simultaneously and consistently the magnetic field geometry and elemental abundance distributions on a stellar surface. For this purpose we analyse time series spectra obtained in Stokes I and V parameters with the SOFIN polarimeter at the Nordic Optical Telescope and recover surface abundance structures of sixteen different chemical elements, respectively ions, including Mg, Ca, Sc, Ti, Cr, Fe, Co, Ni, Y, La, Ce, Pr, Nd, Gd, Tb, and Dy. For the rare earth elements (REE) Pr and Nd separate maps were obtained using lines of the first and the second ionization stage. We find and confirm a clear dipolar structure of the surface magnetic field and an unexpected correlation of elemental abundances with respect to this field: one group of elements accumulates solely where the positive magnetic pole is visible, whereas the other group avoids this region and is enhanced where the magnetic equatorial region dominates the visible stellar surface. We also observe relative shifts of abundance enhancement- or depletion regions between the various elements exhibiting otherwise similar behaviour.Comment: 13 pages, 9 figures, to be published in Astronomy and Astrophysic

Structure And Properties of Nanoparticles Formed under Conditions of Wire Electrical Explosion

Structure and properties of nanoparticles formed under conditions of wire electrical explosion were studied. It was shown that the state of WEE power particles can be characterized as a metastable state. It leads to an increased stability of nanopowders at normal temperatures and an increased reactivity during heating, which is revealed in the form of threshold phenomena.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Formation of the diffusion layer in gas boring

© Published under licence by IOP Publishing Ltd. Boriding in powder media is successfully used to increase the life of parts. To increase the depth of the diffusion layer and improve its properties, a method for activating the surface of a saturable part by means of electromechanical processing is proposed. The results on the structure of the resulting layer and its dimensions are presented

ЗМІНИ В СУДОУСТРОЇ НА УКРАЇНСЬКИХ ЗЕМЛЯХ У СКЛАДІ РОСІЙСЬКОЇ ІМПЕРІЇ У 1796–1801 РР.

Changes in the judicial systems were carried out by Pavlo І and resulted in the loss of class and largely elective character of the judicial system. The emperor renewed privileges and former features in organization of the judicial department in Ukrainian provinces. However, his aim was to strengthen further centralization of rule. Russian power during reformation of the judicial system in the end of the XVIII century proclaimed creation of courts according to European standards concerning the electiveness of judges, all-estate order of consideration of cases, independence. But the dependence of courts was really kept with central and local government bodies. The attempt of Pavlo І to improve the judicial department was aimed at not returning to old times, but creation of more centralized and dependent system, though taking into account some local traditions. However, these changes had short-term character and substantially did not influence on a further evolution and transformation of the judicial system.Досліджено трансформацію судової системи на українських землях, що входило до складу Російської імперії в кінці ХVІІІ ст. Показано суперечливість реформаційних зусиль, зроблених у цій сфері за доби правління імператора Павла І

Судоустрій на українських землях Російської імперії в першій половині XIX ст. (до судової реформи 1864 р.)

After joining of Ukrainian lands the Russian empire got the difficult system of the judicial system in an inheritance. A government used stage-by-stage introduction of principles of the imperial judicial system on Ukrainian earth, especially on parts of Ukraine on a right river Dnepr, where the Russian system of the judicial system was laid on old system that continued to exist and operate. Judicial law that touched the judicial system, not small the special code, and the norms of laws that was contained in different legal institutes were contradictory enough. The structure of the judicial system and cognizance of courts were not clearly certain a court. During the first half of XIX of century the system of class judicial establishments operated on territory of the Ukrainian provinces. Except general courts the judicial system included for itself the special courts: soldiery, commercial, spiritual, mountain. From 1840th the Ukrainian system of rule-making was synchronized with all-Russian.Проаналізовано еволюцію та особливості судової системи на українських землях Російської імперії з початку XIX ст. і до судової реформи 1864 р., висвітлено юрисдикцію цих органів, недоліки тогочасного судоустрою

Application of aluminum nanopowder in hydrogen power engineering

The results of researches on interaction of aluminum nanopowder with water have been given. It is shown, that in conditions of relatively low temperatures aluminum nanopowder totally cooperates with water, allocating "hot" hydrogen. The interaction process is accompanied by the chemical-mechanical effect, decrease of water boiling temperature and self-heating of reacting particles. The formed nanoporous materials have various chemical and phase structure. Advantages and disadvantages of aluminum nanopowder application for obtaining hydrogen are analyzed

Magnetic Doppler Imaging of Active Stars

We present a new implementation of the magnetic Doppler imaging technique, which aims at self-consistent temperature and magnetic mapping of the surface structures in cool active stars. Our magnetic imaging procedure is unique in its capability to model individual spectral features in all four Stokes parameters. We discuss performance and intrinsic limitations of the new magnetic Doppler imaging method. A special emphasis is given to the simultaneous modelling of the magnetically sensitive lines in the optical and infrared regions and to combining information from both atomic and molecular spectral features. These two techniques may, for the first time, give us a tool to study magnetic fields in the starspot interiors.Comment: 4 pages, 3 figures; to appear in the proceedings of Solar Polarization Workshop 5, ASP Conf. Se