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.     

Investigation of the motion of (99942) apophis asteroid using the SKIF cyberia multiprocessor computing system

We present the results of investigation of the dynamics of (99942) Apophis asteroid, which will undergo a very close encounter with the Earth on April 13, 2029. The region of possible motions of the asteroid is considered on the time interval (2004, 2040). In addition, it is shown that an increase of the observational interval (2004, 2006) until 2008 allowed us to reduce significantly the area of possible motions. All investigations were performed by numerical methods with the help of algorithms and software developed by us in the environment of parallel programming using the SKIF Cyberia multiprocessor computer of the Tomsk State University.     

Spaceflight experiments with Arabidopsis starch-deficient mutants support a statolith-based model for graviperception.

In order to help resolve some of the controversy associated with ground-based research that has supported the starch-statolith theory of gravity perception in plants, we performed spaceflight experiments with Arabidopsis in Biorack during the January 1997 and May 1997 missions of the Space Shuttle. Seedlings of wild-type (WT) Arabidopsis, two reduced-starch strains, and a starchless mutant were grown in microgravity and then were given either a 30, 60, or 90 minute gravity stimulus on a centrifuge. By the 90 min 1-g stimulus, the WT exhibited the greatest magnitude of curvature and the starchless mutant exhibited the smallest curvature while the two reduced starch mutants had an intermediate magnitude of curvature. In addition, space-grown plants had two structural features that distinguished them from the controls: a greater number of root hairs and an anomalous hypocotyl hook structure. However, the morphological changes observed in the flight seedlings are likely to be due to the effects of ethylene present in the spacecraft. (Additional ground-based studies demonstrated that this level of ethylene did not significantly affect gravitropism nor did it affect the relative gravitropic sensitivity among the four strains.) Nevertheless, this experiment on gravitropism was performed the "right way" in that brief gravitational stimuli were provided, and the seedlings were allowed to express the response without further gravity stimuli. Our spaceflight results support previous ground-based studies of these and other mutants since increasing amounts of starch correlated positively with increasing sensitivity to gravity.     

Further Results on Multipath Angle Error Reduction Using Multiple-Target Methods

The two-target technique proposed by the author in an earlier paper [1] for reducing radar multipath angle tracking errors has been simulated on a digital computer assuming an actual closed-loop system. When tracking with noise, the technique provides angle error performance which compares quite favorably with the expected performance given in [1] Furthermore, the large bias errors usually encountered in normal monopulse systems at low elevation angles are removed. Results of typical tracks are given, both for the method of [1], and for a modified version of the method which applies primarily to shipboard radar systems. Some results on loss of lock are also presented.     

Experiments with injection of powerful plasma jet into the ionosphere

This paper describes two rocket experiments “Aelita” with high power lithium plasma injection. The results of onboard magnetometer, massspectrometer, photometer, plasma, corpuscular and ground radar measurements are given. Dynamics and structure of plasma formation are discussed.     

Determination of parameters of rotational motion of the <Emphasis Type="Italic">Monitor-E</Emphasis> spacecraft from the telemetry data on solar batteries’ current

The Monitor-E spacecraft executed uncontrolled flight due to emergency situation, no telemetry information on parameters of the spacecraft’s attitude motion being available. So, the problem arose to determine the spacecraft’s rotational motion from the accessible indirect information—the electric current provided by solar batteries. In this paper the integrated statistical technique is described, that allows one to solve this problem. The values of current, obtained over the time interval some tens of minutes long, have been processed simultaneously by the least squares method using the integration of the equations of spacecraft’s rotational motion. As a result of processing, the initial conditions of motion were estimated, and the spacecraft’s moments of inertia were updated, as well as the angles, specifying solar batteries position in the spacecraft-fixed coordinate system. The results of processing of 12 data sets are presented, which allowed us to reconstruct the actual rotational motion of the spacecraft.     

Multiple-Target Monopulse Radar Processing Techniques

The problem of determining target parameters of a known number of radar targets falling in the same range-Doppler-angle-angle resolution cell is examined for the noise-free case. The required minimum number of radar beams is determined, based upon approximating the beam patterns by a Taylor series expansion, both for the general problem and for factorable beams. Signal processors for target position estimation are developed for the two-target case and equations are presented for the general case.     

Amplitude modulation of VLF emission and absorption of cosmic noise by <Emphasis Type="Italic">Pc</Emphasis>5 geomagnetic pulsations in the period of geomagnetic storms on October 30–31, 2003

Modulation of the VLF emission and riometric absorption by Pc5 geomagnetic pulsations is studied in the period of strong geomagnetic disturbances on October 30–31, 2003. Some conclusions about the regime of pitch-angular diffusion into the loss cone are made. The better coincidence of VLF emission modulation with geomagnetic pulsations in other longitude sectors is explained by the global character of excitation of the pulsations and by damping of their amplitudes at the meridian of observation of the VLF emission, which is associated with intensification of auroral electrojets.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 632–639.Original Russian Text Copyright © 2004 by Solovyev, Mullayarov, Baishev, Barkova, Samsonov.     

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.