X-ray scattering by intergalactic dust

The imaging capabilities of the Exosat and Einstein satellites at soft X-ray wavelengths have begun to show that suitable Galactic X-ray sources have extended ( 10 arcmin) haloes due to scattering of soft X-rays by interstellar dust. A simple argument suggests that similar haloes, due to scattering by intergalactic dust, should exist around distant (z 1) quasars and detailed analysis confirms this conclusion. A search for such haloes around suitable X-ray quasars could provide valuable, model-independent, constraints on the amount and origin of intergalactic dust.     

Rational placement and required number of information unmanned aerial systems for on-line monitoring of large territories

An urgent problem of organizing the on-line monitoring of large territories using the information unmanned aerial systems (UAS) is considered. We determine the UAS placement and their necessary number by solving a two-criteria problem on rational covering of the territory by these systems. A man-machine algorithm and an example of the problem solution are presented.     

Exploring the Detached-Eddy Simulation for Main Rotor Flows

This paper applies the Detached-Eddy Simulation (DES) method to resolve a larger part of the flow spectrum around rotor blades in hover and forward flight. A comparison between DES and Unsteady Reynolds–Averaged Navier–Stokes simulation was carried out for the case of a forward flying rotor suggesting that DES has great potential for rotor applications.     

Some aspects of the application of the bunch of MPD engines

In the present work, the asymptotic dependence of the reservation multiplicity on the failure danger diminution coefficient in both cases of reservation replacement and continually acting reserver is investigated. The comparison of the method of reservation for different multiplicities with the method of diminution of the failure intensity, related to the mean performance time shows that the decrease of the failure intensity of the plazma engine is the most rational. Nevertheless, there is a value of the time flight for which even a simple duplication is better than arbitrarily large, though finite, failure intensity decrease of the engine. The reliability of coupled MOD-thrusters is verified experimentally. The specific character of the thruster V-I curves and, in particular, their increase in the pubricrcrisis region, yield normally working couples, conformly to many types of feed sources with weakly decreasing of constant V-I characteristics. The parallel connection of a second thruster is shown to double the customed current and, as a consequence the thruster intermediary regimes of the thruster and the dynamics of switching on and by breaking the electric line and stopping the propellant rate flow are investigated.     

A technique for presentation and application of the propeller fan multidimensional characteristics in semi-full-scale simulation of a gas turbine engine and its automatic control system

A technique for linear interpolation of the multidimensional characteristics of a coaxial propeller fan with opposite rotation propellers is proposed; the technique makes it possible to simulate the turbofan engine operation in the entire range of flight conditions and reduce expenses for fullscale tests. The mathematical models obtained meet the requirements imposed in the semi-full-scale simulation.