Monitoring and modelling of white dwarfs with extremely weak magnetic fields

Magnetic fields are detected in a few percent of white dwarfs. The number of such magnetic white dwarfs known is now some hundreds. Fields range in strength from a few kG to several hundred MG. Almost all the known magnetic white dwarfs have a mean field modulus >= 1 MG. We are trying to fill a major gap in observational knowledge at the low field limit (<= 200 kG) using circular spectro-polarimetry. In this paper we report the discovery and monitoring of strong, periodic magnetic variability in two previously discovered "super-weak field" magnetic white dwarfs, WD2047+372 and WD2359-434. WD2047+372 has a mean longitudinal field that reverses between about -12 and +15 kG, with a period of 0.243 d, while its mean field modulus appears nearly constant at 60 kG. The observations can be intepreted in terms of a dipolar field tilted with respect to the stellar rotation axis. WD2359-434 always shows a weak positive longitudinal field with values between about 0 and +12 kG, varying only weakly with stellar rotation, while the mean field modulus varies between about 50 and 100 kG. The rotation period is found to be 0.112 d using the variable shape of the Halpha line core, consistent with available photometry. The field of this star appears to be much more complex than a dipole, and is probably not axisymmetric. Available photometry shows that WD2359-434 is a light variable with an amplitude of only 0.005 mag, our own photometry shows that if WD2047+372 is photometrically variable, the amplitude is below about 0.01 mag. These are the first models for magnetic white dwarfs with fields below about 100 kG based on magnetic measurements through the full stellar rotation. They reveal two very different magnetic surface configurations, and that, contrary to simple ohmic decay theory, WD2359-434 has a much more complex surface field than the much younger WD2047+372.Comment: Accepted for publication in Astronomy & Astrophysic

Russian Turkology and heritage

The urgency of the problem under study is conditioned by the need to study the history of Turkology development in the modern world. This involves the considering of Russian and European orientalist achievements at the turn of the 19-th and 20-th centuries. The purpose of the article is to give an overview of the Turkic heritage by the Academician A.E. Krymsky and to assess his contribution to Russian and Ukrainian oriental studies. The leading approach to the study of this problem is the problem-thematic approach, as well as the comparative-historical principle. The main results of the study consist in the systematic description of his works on Turkic studies. The main attention is paid to various materials written by him during his work at the Lazarev Institute of oriental languages and at the Ukrainian Academy of Sciences. The scientific directions of his Turkic studies were revealed. The materials of the article can be useful to study the history of world Turkology, for the teaching of languages, history, literature and the culture of the Turkic peoplespeer-reviewe

Acid and Acid-Alkali Treatment Methods of Al-Chloride Solution Obtained by the Leaching of Coal Fly Ash to Produce Sandy Grade Alumina

Sandy grade alumina is a valuable intermediate material that is mainly produced by the Bayer process and used for manufacturing primary metallic aluminum. Coal fly ash is generated in coal-fired power plants as a by-product of coal combustion that consists of submicron ash particles and is considered to be a potentially hazardous technogenic waste. The present paper demonstrates that the Al-chloride solution obtained by leaching coal fly ash can be further processed to obtain sandy grade alumina, which is essentially suitable for metallic aluminum production. The novel process developed in the present study involves the production of amorphous alumina via the calcination of aluminium chloride hexahydrate obtained by salting-out from acid Al-Cl liquor. Following this, alkaline treatment with further Al2 O3 dissolution and recrystallization as Al(OH)3 particles is applied, and a final calcination step is employed to obtain sandy grade alumina with minimum impurities. The process does not require high-pressure equipment and reutilizes the alkaline liquor and gibbsite particles from the Bayer process, which allows the sandy grade alumina production costs to be to significantly reduced. The present article also discusses the main technological parameters of the acid treatment and the amounts of major impurities in the sandy grade alumina obtained by the different (acid and acid-alkali) methods. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 18-79-00305Funding: This work was financially supported by the Russian Science Foundation Project No. 18-79-00305

Climate-induced migration: New challenges and perspectives

© 2018, Advanced Scientific Research. All rights reserved. Climate change has a significant impact on humans and the environment. In this regard, there are people who can no longer gain a secure livelihood in their homelands because of different ecological phenomena, including climate change. These people have to seek shelter from the bad effect of climate change elsewhere, in spite of the hazardous nature of the attempt. In this context, the new definition applicable to such persons is emerging. The reality is that despite the very real nature of the problem, climate change displacement raises more questions than the international community is likely to agree on solving. Keeping this in mind, the present paper examines different perspectives of the definition, applicable international legal framework and proposals on possible means of filling the protection gaps

Concentration of rare earth elements (Sc, y, la, ce, nd, sm) in bauxite residue (red mud) obtained by water and alkali leaching of bauxite sintering dust

One of the potential sources of rare-earth elements (REE) is the industrial waste known as red mud (bauxite residue), in which the majority of REE from the initial bauxite are concentrated via the Bayer process. Therefore, the studies of the subject, both in Russia and outside, focus almost exclusively on red mud processing. This article looks into the possibility of REE concentration into red mud by leaching an intermediate product of the bauxite sintering process at Russian alumina refineries, namely electrostatic precipitator (ESP) dust. The experimental works were performed by X-ray diffraction (XRD)and electron probe microanalysis (EPMA) of the sinter and sinter dust. The determination of major and rare-earth elements in the sinter from the rotary kilns and in the ESP dust before and after leaching was carried out by X-ray fluorescence (XRF) and plasma mass spectrometry (ICP-MS). The study showed that it is possible to obtain red mud that contains three times more REE than traditional waste red mud after two-stage leaching ESP dust in the water at 95◦ C followed by leaching in an alkaline-aluminate liquor at 240◦ C. The shrinking core model was used to study the kinetics of leaching of the original ESP dust and water-treated dust in alkaline-aluminate liquor. The study showed the change in the limiting stage of the alkaline leaching process after water treatment, with the activation energy growing from 24.98 to 33.19 kJ/mol. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 18-19-00186Funding: The research was funded by the Russian Science Foundation, grant number 18-19-00186

Modernization of the russian law: A review of the laws on enforcement proceedings

Modernization of Russian law covers many spheres including enforcement proceedings. The existing legislation on the enforcement proceedings, which has been reformed for last 15 years, serves as basis of modernization. The scientific doctrine and system of enforcement proceedings in Russia have gradually been developed; it includes such fundamental documents as the Constitution of the Russian Federation, international treaties, both substantive and procedural law of the Russian Federation in the area of enforcement proceedings and also court decisions. Furthermore, the importance of the European Court of Human Rights in relation to enforcement proceedings increases in Russia

The effect of exercise on the body during the period of educational-cognitive activity of the student

In the article the processes of influence of physical exercises on the human body. Updated the importance of regular physical activity. Identified the need for systematic training not only in the classroom for physical education in higher education, but also in self-training, subject to the physical condition of the body and the proper selection of means of physical cultureВ статье рассмотрены процессы влияния занятий физическими упражнениями на организм человека. Актуализировано значение регулярных физических нагрузок. Выявлена необходимость систематических занятий не только на учебных занятиях по физической культуре в вузе, но и в самостоятельной подготовке с условием учета физического состояния организма и правильного подбора средств физической культур

Two New LBV Candidates in the M33 Galaxy

We present two new luminous blue variable (LBV) candidate stars discovered in the M33 galaxy. We identified these stars (Valeev et al. 2010) as massive star candidates at the final stages of evolution, presumably with a notable interstellar extinction. The candidates were selected from the Massey et al. (2006) catalog based on the following criteria: emission in Halpha, V<18.5 and 0.35<(B-V)<1.2. The spectra of both stars reveal a broad and strong Halpha emission with extended wings (770 and 1000 km/s). Based on the spectra we estimated the main parameters of the stars. Object N45901 has a bolometric luminosity log(L/Lsun)=6.0-6.2 with the value of interstellar extinction Av=2.3+-0.1. The temperature of the star's photosphere is estimated as Tstar~13000-15000K its probable mass on the Zero Age Main Sequence is M~60-80Msun. The infrared excess in N45901 corresponds to the emission of warm dust with the temperature Twarm~1000K, and amounts to 0.1% of the bolometric luminosity. A comparison of stellar magnitude estimates from different catalogs points to the probable variability of the object N45901. Bolometric luminosity of the second object, N125093, is log(L/Lsun)=6.3-6.6, the value of interstellar extinction is Av=2.75+-0.15. We estimate its photosphere's temperature as Tstar~13000-16000K, the initial mass as M~90-120Msun. The infrared excess in N125093 amounts to 5-6% of the bolometric luminosity. Its spectral energy distribution reveals two thermal components with the temperatures Twarm~1000K and Tcold~480K. The [CaII] lines (7291A and 7323A), observed in LBV-like stars VarA and N93351 in M33, are also present in the spectrum of N125093. These lines indicate relatively recent gas eruptions and dust activity linked with them. High bolometric luminosity of these stars and broad Halpha emissions allow classifying the studied objects as LBV candidates.Comment: 14 pages, 4 figure