1,119 research outputs found
Theory and Design of Flight-Vehicle Engines
Papers are presented on such topics as the testing of aircraft engines, errors in the experimental determination of the parameters of scramjet engines, the effect of the nonuniformity of supersonic flow with shocks on friction and heat transfer in the channel of a hypersonic ramjet engine, and the selection of the basic parameters of cooled GTE turbines. Consideration is also given to the choice of optimal total wedge angle for the acceleration of aerospace vehicles, the theory of an electromagnetic-resonator engine, the dynamic characteristics of the pumps and turbines of liquid propellant rocket engines in transition regimes, and a hierarchy of mathematical models for spacecraft control engines
Observations of Sy2 galaxy NGC 3281 by XMM-Newton and INTEGRAL satellites
We present here the results of our analysis of X-ray properties of Seyfert 2
galaxy NGC 3281, based on the observational data obtained by XMM-Newton and
INTEGRAL within the energy ranges 0.2-12 keV and 20-150 keV, respectively. The
XMM-Newton spectrum of this object is presented for the first time. We show
that fitting the X-ray spectrum of this galaxy with models based on the
reflection from the disc with infinite column density yields non-physical
results. More appropriate fit takes into account both transmitted and reflected
emission, passed through a gas-dusty torus-like structure. Keeping this in
mind, to model the inhomogeneous clumpy torus, we used the MYTorus model.
Hence, we propose that the torus of NGC 3281 is not continuous structure, but
it consists of separate clouds, which is in a good agreement with the results
of near-IR observations. Using this assumption, we found that the torus
inclination angle and the hydrogen column density are 66.98^{+2.63}_{-1.34}
degrees and 2.08^{+0.35}_{-0.18}x10^{24} cm^{-2}, respectively. Also, the
emission of the hot diffuse gas with temperature ~590 eV and warm absorption
were detected.Comment: 8 pages, 5 figures, 2 tables, accepted for publication in Advances in
Astronomy and Space Physic
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