Global Properties of Solar Flares

This article broadly reviews our knowledge of solar flares. There is a particular focus on their global properties, as opposed to the microphysics such as that needed for magnetic reconnection or particle acceleration as such. Indeed solar flares will always remain in the domain of remote sensing, so we cannot observe the microscales directly and must understand the basic physics entirely via the global properties plus theoretical inference. The global observables include the general energetics—radiation in flares and mass loss in coronal mass ejections (CMEs)—and the formation of different kinds of ejection and global wave disturbance: the type II radio-burst exciter, the Moreton wave, the EIT “wave”, and the “sunquake” acoustic waves in the solar interior. Flare radiation and CME kinetic energy can have comparable magnitudes, of order 10³² erg each for an X-class event, with the bulk of the radiant energy in the visible-UV continuum. We argue that the impulsive phase of the flare dominates the energetics of all of these manifestations, and also point out that energy and momentum in this phase largely reside in the electromagnetic field, not in the observable plasma.     

Optimization of the centrifugal impeller flow passage in high-speed pumps

Based on the jet-vortex model for flow passage hydrodynamics in a high-speed centrifugal pump with the open-type impeller, we present the calculated relations for design and optimization of the experimentally verified pump design parameters.     

Application of the parameter-averaging method to calculations of gas ejectors with cylindrical mixing chambers

In this paper, one of the most possible methods for calculations of ejector devices equipped with the cylindrical mixing chambers is considered; the method is based on averaging the flow parameters at the chamber inlet. We present the calculation results and their comparison with the earlier published data, as well as the quantitative assessment of this method and feasibilities of its use for different technical devices embodying the concept of ejection.     

Optimization of a tool kit for machining by methods of graph theory

Some methods of optimizing a cutting tool kit by the minimum labour content criterion in milling of an article are considered. Their advantages and disadvantages are given.     

Heat transfer at various methods of thermal protection in the systems of power-driven gas turbine plants (GTP)

The scheme variants of implementing the thermal protection against heat flows being generated by the body of a high-temperature stationary gas turbine engine (GTE) are presented. The scheme of the experimental bench with a working section is given. Methodical approaches to the heat transfer calculation at different variants of forced and natural convection organization and under various operating conditions are described. The generalized results of the experiments carried out using a heat curtain being generated by porous injection are presented.     

On choice of the blade back profile curvature in transonic turbine cascades

Some design and experimental data on three cascades with the same 12° bending angle for the primary nozzle block of a gas turbine are presented. As is seen from the investigation the most efficient at the transonic velocities of the outward flow are the blades, the back curvature of which in the bevel cut zone decreases to the trailing edge. Also presented is the fact that the blade with the increasing back curvature has noticeably larger losses.     

System sensitivity to parametric variations in the problem of lateral motion flight vehicle control

The results of investigation of dynamic system sensitivity to parametric variations in the channel of flight vehicle lateral motion are presented using the notion of infinitesimal transformation. The exact relationships establishing a link between the structure of parameter deviation and that of system phase coordinate deviation are obtained.     

Seasonal and diurnal behavior of NO2 column density in Antarctica as observed by Mark IV,Brewer Ozone Spectrophotometer Number 153

The Meteorology Department of India has been measuring vertical column density of NO₂ at Maitri (70.7°S, 11.7°E), Antarctica since July 1999 using a Mark IV, Brewer Ozone Spectrophotometer. Maitri is situated at the south of the Antarctic circle. An analysis of 6 years of data shows that NO₂ column has seasonal variation with a maximum value during summer. It is also found that during the period when sun does not set, the NO₂ column exhibits a diurnal variation, with a peak around noon and lower values in the morning and afternoon hours. Using a simple steady-state chemical reaction scheme, an attempt has been made to explain these features.     

Pre-storm behaviour of NmF2 and TEC (GPS) over equatorial and low latitude stations in the Indian sector

The pre-storm behavior of NmF₂ and TEC over an equatorial station, Trivandrum (8.47°N, 76.91°E, dip 0.6°S) and a low latitude station, Waltair (17.7°N,83.3°E, dip 20°N) has been studied for a total of 18 strong geomagnetic storms with DST ? −100 nT. The simultaneous measurements of GPS-TEC and NmF₂ over Trivandrum and Waltair during the period 2000–2005 have been considered for the present study. It is found that there is a substantial increase in NmF₂ and TEC before the onset of the storm over Waltair, while the increase is not present at Trivandrum. The origin of pre-storm enhancements in electron density still remains unresolved owing to several conditions in their potential sources and occurrence mechanisms. In the present study an attempt is made to identify the possible mechanisms responsible for such enhancements in electron density of the F-region.