231 research outputs found
Magnesium-Containing Slurry as Technogenic Alternative Raw Material for Magnesium Oxychloride Cement
It has been shown experimentally that a waste of magnesium metal production is a realistic alternative to naturally occurring cement raw materials. The waste is the carnallite slurry forming during the chlorination stage. The slurry contains magnesium oxide (MgO) and magnesium chloride (MgCl2) in a mass ratio close to their optimal ratio when preparing Sorel cement. It is found that the magnesium oxide in the slurry is highly reactive. MgO extracted from the slurry and MgCl2 solution are mixed forming homogeneous magnesium oxychloride cement (MOC) paste in which bonding crystalline structures typical for Sorel cement are formed during hardening. © 2019 Published under licence by IOP Publishing Ltd
Synthesis and sorption properties of filled fibrous sorbents with immobilized hetarylformazan groups
New sorbents were prepared by immobilization of structurally different sulfur-containing hetaryl-formazans on nonwoven polyacrylonitrile fiber tilled with AV-17 anion exchanger. Sorption of some heavy metals on these materials was studied as influenced by various factors. Sorbents for selective recovery of copper(II) in the presence of nickel(II), zinc(II), and cadmium(II) cations were found
Synthesis and catalytic properties of copper(II) 1-aryl-5-benzothiazolylformazanates
New copper(II) benzothiazolylformazane complexes were synthesized and immobilized on AN-18 anion exchanger. The influence of the composition of the coordination core of copper(II) benzthiazolylformazanates and temperature on their catalytic properties in decomposition of H2O2 and oxidation of Na2S in aqueous solution was studied
Galactic Binary Gravitational Wave Noise within LISA Frequency Band
Gravitational wave noise associated with unresolved binary stars in the
Galaxy is studied with the special aim of determining the upper frequency at
which it stops to contribute at the rms noise level of the proposed space-born
interferometer (LISA). The upper limit to this background is derived from the
statistics of SN Ia explosions, part of which can be triggered by binary white
dwarf coalescences. The upper limiting frequency at which binary stochastic
noise crosses LISA rms sensitivity is found to lie within the range 0.03-0.07
Hz, depending on the galactic binary white dwarf coalescence rate. To be
reliably detectable by LISA, the energy density of relic cosmological
background per logarithmic frequency interval should be
Omega_{GW}h_{100}^2>10^{-8} at f>0.03 Hz.Comment: 16 pages with 1 eps figure, aasms4.sty, to appear in the ApJ vol. 494
February 20, 1998 issu
Trans-sonic propeller stage
We follow the approach used by Davies and Pringle (1981) and discuss the
trans-sonic substage of the propeller regime. This substage is intermediate
between the supersonic and subsonic propeller substages. In the trans-sonic
regime an envelope around a magnetosphere of a neutron star passes through a
kind of a reorganization process. The envelope in this regime consists of two
parts. In the bottom one turbulent motions are subsonic. Then at some distance
the turbulent velocity becomes equal to the sound velocity.
During this substage the boundary propagates outwards till it
reaches the outer boundary, and so the subsonic regime starts.
We found that the trans-sonic substage is unstable, so the transition between
supersonic and subsonic substages proceeds on the dynamical time scale. For
realistic parameters this time is in the range from weeks to years.Comment: 8 pages with figures, submitted to Astron. Astroph. Transaction
Synthesis and spectroscopic features of iron(II) 1-aryl-5-benzothiazol-2- ylformazanates
New iron(II) coordination compounds with 1-aryl-5-(benzothiazol-2-yl) formazans were prepared. Their compositions and structures were determined by electronic spectroscopy, mass spectrometry, single crystal X-ray diffraction analysis, and magnetochemical measurements. © 2008 Pleiades Publishing, Ltd.Russian Foundation for Basic Researc
Luminosity function of binary X-ray sources calculated using the Scenario Machine
Using the ``Scenario Machine'' we have carried out a population synthesis of
X-ray binaries for the purpose of modelling of X-ray luminosity functions
(XLFs) in different types of galaxies: star burst, spiral, and elliptical. This
computer code allows to calculate, by using Monte Carlo simulations, the
evolution of a large ensemble of binary systems, with proper accounting for the
spin evolution of magnetized neutron stars.
We show that the XLF has no universal type. It depends on the star formation
rate in the galaxy. Also it is of importance to take into account the evolution
of binary systems and life times of X-ray stages in theoretical models of such
functions. We have calculated cumulative and differential XLFs for the galaxy
with the constant star formation rate. Also we have calculated cumulative
luminosity functions for different intervals of time after the star formation
burst in the galaxy and curves depicting the evolution of the X-ray luminosity
after the star formation burst in the galaxy.Comment: 22 pages, 13 figure
The Economic Foundations of the Rule of Law in the Russian Federation
This study, based on the economic and legal metrics of the Russian Federation, considers the possibility of implementing the concept of the rule of law in the modern world. The study emphasises the issue of the rule of law in any country being directly related to the problem of redistribution of public goods. In many ways, this can be considered an example of how economic stability ensures legal stability. The research methodology includes a dialectical method, which allowed to ensure compliance with the principles of scientific knowledge. The study shows the dynamics of ensuring human rights, the distribution of income and expenses in society over different periods in the history of the Russian Federation. In this regard, the authors come to the conclusion that the perception and functions of the concept of the rule of law will soon deviate from classical liberal values towards the basic ideas of social equality and justice
Population synthesis of old neutron stars in the Galaxy
The paucity of old isolated accreting neutron stars in ROSAT observations is
used to derive a lower limit on the mean velocity of neutron stars at birth.
The secular evolution of the population is simulated following the paths of a
statistical sample of stars for different values of the initial kick velocity,
drawn from an isotropic Gaussian distribution with mean velocity . The spin-down, induced by dipole losses and the
interaction with the ambient medium, is tracked together with the dynamical
evolution in the Galactic potential, allowing for the determination of the
fraction of stars which are, at present, in each of the four possible stages:
Ejector, Propeller, Accretor, and Georotator. Taking from the ROSAT All Sky
Survey an upper limit of accreting neutron stars within pc
from the Sun, we infer a lower bound for the mean kick velocity, \ga
200-300 . The same conclusion is reached for both a constant
( G) and a magnetic field decaying exponentially with a
timescale yr. Present results, moreover, constrain the fraction of
low velocity stars, which could have escaped pulsar statistics, to \la 1%.Comment: 8 pages, 4 PostScript figures, to appear in the proceedings of IAU
Symposium 19
- …