Infrared radiation from compact X-ray sources

Observations of the X-ray binaries 4U 0115+634 and A 0535+262 performed in 1981 – 1982 revealed significant IR variabilities of these sources. 4U 0115+634 was observed twice, in the state close to X-ray activity, and in the state of low activity, thus changing from K = 7^m.75 to K > 9^m. A 0535+262 shows the temporal variations ranged from tens minutes to some days. The regular variations of IR brightness are suspected with teh period close to 104 s that corresponds to the period of axial rotation of neutron star in A 0535+262. The results obtained present arguments in favour of hypothesis that IR radiation is generated near the accreting neutron star and is possibly of maser nature.     

The asymmetry of the solar cycle: A result of non-linearity

The paper presents a numerical analysis of Wolf sunspot numbers, with emphasis being laid on the asymmetry of the cyclic variation. To that purpose we have used the standard tables of monthly numbers and, in addition to the Fourier transform, we have done an overall analysis of the trend around each maximum. Many of these maxima present an asymmetry, and sometimes the presence of two maxima is evident. The non-linear RLC van der Pol model suggested by Polygiannakis and Moussas [Polygiannakis, J.M., Moussas, X. A nonlinear RLC solar cycle model. Solar Physics 163, 193–203, 1996] can explain many features of the observed asymmetries. Our analysis shows that a consistent deconvolution in two Gaussian curves is possible for each maximum. We may presume that the observed sunspot time series includes a hidden complex structure. This could give some hints of a behavior typical for coupled non-linear oscillators. It is a matter of further interpretations. whether such “oscillators” are just a simple approximation of a much complex phenomenon, or are a sign of another more physically based model like the dynamo model (or other models).     

Estimation of plasma density from wave data of cold electron plasma

Based on the dispersion relation of electron plasma, one can expect, that the waves excited in the frequency band (f_p, f_u=sqrt(f_p^*f_p+f_c^*f_c)) should persist in experimental spectra. For wave data from a spacecraft immersed in a cold plasma such an assumption may be misleading. In measurements performed on board the INTERCOSMOS-19, ACTIVE, APEX satellites and VC36.064CE rocket the most prominent spectral structure is centered around frequency f_r fulfilling the relation f_crp and corresponds to resonant detection of Bernstein waves excited in the surrounding plasma by spacecraft systems. Input network mismatch at frequencies around fu significantly depresses natural plasma noise as well as that excited by the spacecraft. Plasma emissions in the band (f_p, f_u) are prominent if the electromagnetic excitation is preferential (topside sounders) or if the excitation introduces nonequilibrium components into the plasma e.g. particle beams or clouds. Experimental examples are presented and parameters of cold plasma spectra useful for electron density estimation are discussed. The application to other spacecraft-cold plasma configurations is suggested.     

Phase resolved study of the CRSF in MX 0656-072

MXB 0656-072 is an accreting X-ray pulsar with a Be star companion, showing notable emission in H. In October 2003 this system exhibited a large and extended X-ray outburst. RXTE observations during this outburst indicated a pulse period of 160.4 s and a cyclotron resonance scattering feature in the spectrum at 32 keV. This paper presents pulse profile analysis and phase-resolved X-ray spectroscopy of RXTE observations during this outburst.     

Do heavy ions cause microlesions in cell membranes?

Heavy ions are a hazard in manned deep space missions. It has been theoretically postulated that when they interact with cells, localized damage in the forms of "microlesions" may occur. Purported morphological evidence of these lesions, however, has not been confirmed in the most extensively studied tissue so far, the cornea. Recent morphological evidence from rat corneas demonstrated that holes in membranes do not form as consequence of heavy ion irradiation. This does not mean, however, that some other form of damage is excluded. For example such damage may be physiological in nature, impairing the ability of cells or tissues to function properly. In order to uncover any physiological effects, we investigated the microlesion question by monitoring the electrical potential difference across the endothelium of rat corneas in vitro before, during, and after irradiation. When the corneas were exposed to 1 Gy of 56Fe ions (450 and 600 MeV/a.m.u.), we detected no effect on this parameter. These results suggest that direct physical damage to cell membranes, as predicted by the microlesion theory, does not take place.     

"Mir" radiation dosimetry results during the solar proton events in September-October 1989.

Using data from dosimetry-radiometry system "Liulin" on board of "Mir"-space station the particle flux and doserate during September-October, 1989 has been studied. The orbit of the station was 379 km perigee, 410 km apogee and 51.6 degrees inclination. Special attention has been paid to the flux and doserate changes inside the station after intensive solar proton events (SPE) on 29 of September, 1989. The comparison between the doses before and after the solar flares shows increase of the calculated mean dose per day by factor of 10 to 200. During the SPE on the 29 of September the additional dose was 310 mrad. The results of the experiment are compared with the data for the solar proton fluxes obtained on the GOES-7 satellite.     

Biological role of gravity: hypotheses and results of experiments on "Cosmos" biosatellites.

In order to reveal the biological significance of gravity, microgravity effects have been studied at the cellular, organism and population levels. The following questions arise. Do any gravity-dependent processes exist in a cell? Is cell adaptation to weightlessness possible; if so, what role may cytoskeleton, the genetic apparatus play in it? What are the consequences of the lack of convection in weightlessness for the performance of morphogenesis? Do the integral characteristics of living beings change in weightlessness? Is there any change in "biological capacity" of space, its resistance to expansion of life? What are the direction and intensity of microgravity action as a factor of natural selection, the driving force of evolution? These problems are discussed from a theoretical point of view, and in the light of results obtained in experiments from aboard biosatellites "Cosmos".     

Algorithms of Constructing the Regions of Initial States for Unmanned Winged Gliders

The algorithms of controlled descent for unmanned winged gliders are designed taking into account the requirements to the flight trajectory. The calculation results are represented to show the efficiency of the algorithms.     

Fuel atomization and mixing in unsteady swirling flows behind the gas-dynamic stabilizer

Features of fuel atomization and propagation in the flow behind a gas-dynamic stabilizer are considered. Estimations of the influence of transverse jets impulse magnitude on characteristics of mixing behind the stabilizer are obtained by numerical and experimental methods.