Interplanetary scintillations of the radio source ensemble at the maximum of cycle 24 of solar activity

The results of the interplanetary scintillation observations performed in the period of the maximum of solar activity from April 2013 to April 2014 on the BSA LPI radio telescope at the frequency 111MHz are presented. Fluctuations of the radio emission flux were recorded round the clock for all sources with a scintillating flux of more than 0.2 Jy falling in a strip of sky with a width of 50° over declinations corresponding to a 96-beam directional pattern of the radio telescope. The total number of sources observed during the day reaches 5000. The processing of the observational data was carried out on the assumption that a set of scintillating sources represents a homogeneous statistical ensemble. Daily two-dimensional maps of the distribution of the level of scintillations, whose analysis shows the strong nonstationarity and large-scale irregularity of the spatial distribution of solar wind parameters, were constructed. According to maps of the distribution of the level of scintillations averaged over monthly intervals, the global structure of the distribution of the solar wind was investigated in the period of the maximum of solar activity, which was found to be on the average close to spherically symmetric. The data show that on a spherically symmetric background an east–west asymmetry is observed, which indicates the presence of a large-scale structure of a spiral type in the solar wind.     

Determination of Gas-Generator Fuel Capacity for Hybrid Aerial Underwater Vehicles with Airfoil Cavity-Forming System

We determine the behavior of onboard gas-generator flowrate for generating the cavitation flow around a hybrid aerial underwater vehicle by using an annular wing on the underwater trajectory section.     

Numerical scheme of the second order of accuracy for vortex methods for incompressible flow simulation around airfoils

A high-accuracy numerical scheme is proposed for vortex methods of flow simulation around airfoils of arbitrary shape including airfoils with sharp edges, because it does not require the solution continuity on the airfoil.     

Influence of the helicopter flight design speed on the selection of working process parameters for GTE

This paper considers issues of designing a gas-turbine engine in the helicopter system at the early design stages. The optimum and rational values of engine working process parameters at different flight speeds of the flight vehicle (FV) are analyzed. Several characteristics of mathematical models (MM) that form the helicopter–engine system, are described.     

Dynamics of a discretely reinforced cylindrical shell under live load

This study proposes an approximate solution to a contact problem of dynamic deformation of a cyclically symmetrical discretely ring-stiffened cylindrical shell, the side surface of which is subjected to an evenly distributed inertia live load. The solution of the problem assumes the quasistatic mode of deformation of the structure. Several critical velocities of the live load have been found. A number of examples are presented.     

Very Long Baseline Interferometry: Dependencies on Frequency Stability

Very Long Baseline Interferometry (VLBI) is a differential technique observing radiation of compact extra-galactic radio sources with pairs of radio telescopes. For these observations, the frequency standards at the telescopes need to have very high stability. In this article we discuss why this is, and we investigate exactly how precise the frequency standards need to be. Four areas where good clock performance is needed are considered: coherence, geodetic parameter estimation, correlator synchronization, and UT1 determination. We show that in order to ensure the highest accuracy of VLBI, stability similar to that of a hydrogen maser is needed for time-scales up to a few hours. In the article, we are considering both traditional VLBI where extra-galactic radio sources are observed, as well as observation of man-made artificial radio sources emitted by satellites or spacecrafts.     

Method of determining the maximum permissible values for diagnostic signs of helicopter transmission units operational status

A method of determining the maximum permissible values for diagnostic signs, being an integral part of health and usage monitoring systems (HUMS) of the helicopter transmission units, has been developed based on a probabilistic approach.     

X-Ray Observations of Powerful AGN Outflows

Highly ionised winds with velocities ～0.1–0.2c were first detected in X-ray spectra of non-BAL AGN a decade ago. Subsequent observations and archival searches have shown such winds to be a common feature of luminous AGN, increasing the belief that powerful ionised winds have a wider importance in galaxy feedback models. Paradoxically, for the best-quantified high velocity outflow (the luminous Seyfert PG1211+143) the wind appears too powerful to be compatible with the observed stellar bulge and black hole masses, suggesting the energy coupling of wind to bulge gas must be inefficient. A recent XMM-Newton observation of the narrow line Seyfert NGC 4051 offers an explanation of this apparent paradox, finding evidence for the fast ionised wind to lose most of its kinetic energy after shocking against the ISM. Importantly, the wind momentum is maintained through such a shock, supporting the view that a momentum-driven flow provides the critical link between black hole and stellar bulge growth implied by the observed M–σ relationship.     

Study of thin-walled parts shaping process based on flanging and embossing

This paper presents the results of analyzing the shaping of thin-walled conical parts with the uniform thickness along generatrix.