Comparative analysis of mixing chambers for two multiphase flows of oppositely charged particles

In this paper, we formulated the criteria for evaluating the effectiveness of mixing chambers, needed in obtaining polymeric materials with reproducible properties. The results of comparative analysis of organizing the methods for mixing two multiphase flows of oppositely charged particles are presented. This analysis, carried out using CFD programs, shows that the mixing chamber construction in which the flows being mixed are directed at an angle to each other, and additional gas flow inlets are provided in the lateral wall, is the most efficient.     

EUVITA — An extreme UV imaging telescope array with spectral capability

EUVITA is a set of 8 extreme UV normal incidence imaging telescopes, each of them sensitive in a narrow band (λ/Δλ = 15 to 80), centered at wavelengths between 50 and 175 Å. Each telescope has an effective area of a few cm²; a field of view of 1.2° and a spatial resolution of 10 arcsec.

EUVITA will be flown on the Russian mission SPECTRUM X-G. This satellite will be launched in a highly eccentric orbit with a period of 4 days, allowing long, uninterrupted observations (e.g. 10⁵ seconds). EUVITA's narrow spectral bands allow the measurement of source parameters such as temperature or power law index as well as interstellar absorption, and will resolve groups of strong lines emitted by optically thin hot plasmas.     

Hydromagnetic motions in the magnetosphere

Following a brief specification and historical review of hydromagnetic motions in the magnetosphere, the principles of the governing and limiting processes are surveyed. A formal proof of the well-known hydromagnetic theorem is included, and its interpretation in terms of frozen fields is discussed. Some consequences of its application to the magnetosphere are then described, and the value of equipotentials as a means of illuminating the discussion is established. Departures from the hydromagnetic approximation are then evaluated, and their resultant currents described.The general principles find application in a number of processes: rotation, high-latitude circulation in quiet and disturbed conditions, more widespread convection under continuous dynamo action, and irregular motion both of an unstable and of a forced type. All these are reviewed, and one emergent point is emphasized: that direct evidence for the hydromagnetic motions is lacking, but that it can and should be sought.     

Study of cosmic rays and light flashes on board Space Station MIR: the SilEye experiment.

The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of FLF(Hz) ( 4 2) 10(3) 5.3 1.7 10(4) Fpart(Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on MIR in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998.     

On the Isotopic Composition of Primordial Xenon in Terrestrial Planet Atmospheres

Xenon plays a crucial role in models of atmospheric evolution in which noble gases are fractionated from their initial compositions to isotopically heavier distributions by early hydrodynamic escape of primordial planetary atmospheres. With the assumption that nonradiogenic Xe isotope ratios in present-day atmospheres were generated in this way, backward modeling from these ratios through the fractionating process can in principle identify likely parental Xe compositions and thus the probable sources of noble gases in pre-escape atmospheres. Applied to Earth, this approach simultaneously establishes the presence of an atmospheric Xe component due principally to fission of extinct ²⁴⁴Pu and identifies a composition called U-Xe as primordial Xe. Pu-Xe comprises 4.65±0.30% of atmospheric ¹³⁶Xe, and 6.8±0.5% of the present abundance of ¹²⁹Xe derives from decay of extinct ¹²⁹I. U-Xe is identical to the measured composition of solar-wind Xe except for deficits of the two heaviest isotopes – an unexpected difference since the modeling otherwise points to solar wind compositions for the lighter noble gases in the primordial terrestrial atmosphere. Evidence for the presence of U-Xe is not restricted to the early Earth; modeling based on a purely meteoritic data set defines a parental component in chondrites and achondrites with the same isotopic distribution. Results of experimental efforts to measure this composition directly in meteorites are promising but not yet conclusive. U-Xe also appears as a possible base component in interstellar silicon carbide, here with superimposed excesses of ¹³⁴Xe and ¹³⁶Xe six-fold larger than those in the solar wind. These compositional differences imply mixing of U-Xe with a nucleogenetic heavy-isotope component whose relative abundance in the solar accretion disk and in pre-solar environments varied both spatially and temporally. In contrast to Earth, the U-Xe signature on Mars was apparently overwhelmed by local accretion of materials rich in either chondritic Xe or solar-wind Xe. Data currently in hand from SNC meteorites on the composition of the present atmosphere are insufficiently precise to constrain a modeling choice between these two candidates for primordial martian Xe. They likewise do not permit definitive resolution of a ²⁴⁴Pu component in the atmosphere although its presence is allowed within current measurement uncertainties. This revised version was published online in June 2006 with corrections to the Cover Date.     

Structure of the earth’s magnetosheath at small fluctuations in the interplanetary magnetic field direction

Spatial structure of the magnetosheath of the Earth was studied under the conditions when no sharp (more than 40° during 5 min) changes in the interplanetary magnetic field direction were observed. On the basis of 24 flights of the Interball-1 satellite through the magnetosheath, it is found that three regions differing from each other by parameters of the field and plasma can be observed in the magnetosheath under the above-indicated conditions. These regions also differ from the solar wind region before front of the Earth’s magnetospheric bow shock. Empirical distributions of parameters were studied in each region. Taking into account the influence of the interplanetary magnetic field direction on the processes in the magnetosheath, the cases of quasi-perpendicular and quasi-parallel shock waves were considered separately. The study showed that the distribution of parameters in the selected regions (in the solar wind before front of the bow shock, in the magnetosheath behind the bow shock (post-shock), in the region of the magnetosheath with minimal fluctuations in the field, and in the inner magnetosheath) differ from each other at any interplanetary magnetic field direction.     

Analysis of static loading of a helicopter tubular skid landing gear

A three-dimensional design model of a helicopter tubular skid landing gear based on the application of the large beam displacement theory is presented. The design model takes into account special features of constructive, physical and geometrical deformation nonlinearity. The analysis of a real helicopter structure is given that confirms sufficient validity of calculation results obtained using the model developed by comparing with the results of the finite element analysis.