Study of the radiation environment on MIR space station with SILEYE-2 experiment.

In this work we present preliminary results of nuclear composition measurements on board space station MIR obtained with SILEYE-2 particle telescope. SILEYE-2 was placed on MIR in 1997 and has been working since then. It consists of an array of 6 active silicon strip detectors which allow nuclear and energetic identification of cosmic rays in the energy range between approximately 30 and 200 MeV/n. The device is attached to an helmet and connected to an eye mask which shields the cosmonaut eyes from light and allow studies of the Light Flashes (LF) phenomenon. In addition to the study of the causes of LF, the device is used to perform real time long term radiation environment monitoring inside the MIR, performing measurements in solar quiet and active days.     

A low cost steerable radio-telescope

We present the technical characteristics of a low-cost radio telescope for solar/non solar observations at decimetric (1200–1700 MHz) and centimetric (2700 and 5000 MHz) wavelengths known as Brazilian Decimetric Array (BDA). The technical specifications of the antenna, tracking system, log-periodic feed, preamplifier and the frequency-synthesised receiver with a Single Side Band (SSB) video output of 2.5 MHz are given.     

Baywatch practical automatic detection of intrusion over water

This paper describes one solution to the problem of providing Perimeter Intruder Detection, (PIDS), for sites whose boundary includes direct access from uncontrolled water. Two surveillance heads were proposed, each consisting of a TI camera and a Colour CCTV camera mounted on a pan and tilt unit     

Application of the Method of Integral Manifolds for Construction of Resonant Curves for the Problem of Spacecraft Entry into the Atmosphere

The separation of motions into slow (precession) and fast (nutation) components in the problem of the entry of a spacecraft (SC) with a small asymmetry into the atmosphere is considered. For the separation of the slow and fast motions the method of integral manifolds is used together with the asymptotic method for singularly perturbed systems. The separation of motions allows one to isolate the frequencies that are functions of the slow variables of a system, and further on, after determining the integer relations between them, to construct the resonant curves (surfaces). This method gives the possibility to analyze the conditions of the emergence of resonances for a SC at angles of attack that are not small and when aerodynamic characteristics are nonlinear. Examples of the construction of resonant curves for a SC with typical aerodynamic characteristics are considered.     

Blue Jets: Upward Lightning

Blue jets are beams of blue light propagating from the tops of active thunderclouds up to altitudes of ～50 km. They resemble tall trees with quasi-vertical trunk and filamentary branches. Their apparent speeds are in the range of 10 s to 100 s km/s. Other events, having essentially lower terminal altitudes (<26 km), are named blue starters. These phenomena represent the first documented class of upward electrical discharges in the stratosphere. Some of upward discharges, termed gigantic jets, propagate into the lower ionosphere at much higher speeds in the final phase. We describe salient features of the upward discharges in the atmosphere, give an assessment of the theories of their development, and discuss the consequences for the electrodynamics and chemistry of the stratosphere. We argue that this upward lightning phenomenon can be understood in terms of the bi-directional leader, emerging from the anvil.     

Use of the ASTER satellite images for evaluation of structural changes in the Popocatépetl volcano related to microseismicity

Mexico is one of the most volcanically active regions in North America. Volcanic activity in central Mexico is associated with the subduction of the Cocos and Rivera plates beneath the North American plate. Periods of enhanced microseismic activity, associated with the volcanic activity of the Popocatépetl volcano are compared with periods, during which the microseismic activity was low. We detected systematical changes in the number of lineaments, associated with the microseismic activity due to lineament analysis of a temporal sequence of high resolution satellite images of the Popocatépetl volcano, provided by the ASTER/VNIR instrument. The Lineament Extraction and Stripes Statistic Analysis (LESSA) software package was used for the lineament extraction. In the future it would allow develop a methodology for detection of possible elevation of pressure in volcano edifice.     

3-D position estimation of isolated target and optimal trajectory choice in parasitic synthetic aperture radar

Bistatic SAR (BSAR) systems have recently been the subject of several studies, but little attention has been given to the potential of the location of targets. In the paper, the performance of the estimation of 3-D position of a target (TPE) in parasitic SAR is obtained analytically and illustrated by computer simulation using ambiguity function analysis, and the maximum likelihood estimate (MLE) approach. It was shown that by using a multi look parasitic BSAR all three coordinates of an isolated point target (IPT) could be evaluated. Analytical closed form equations that characterize the measurement accuracy were derived. In the final these equations will be used to demonstrate various cases of more practical, including optimal trajectories choice under any geometry configuration case, moreover, the conclusion is verified via Matlab.     

Comparison of mesopause region meteor radar winds,medium frequency radar winds and low frequency drifts over Germany

During 2004 and 2005 measurements of mesospheric/lower thermospheric (80–100 km) winds have been carried out in Germany using three different ground-based systems, namely a meteor radar (36.2 MHz) at the Collm Observatory (51.3°N, 13°E), a MF radar (3.18 MHz) at Juliusruh (54.6°N, 13.4°E) and the LF D1 measurements using a transmitter (177 kHz) at Zehlendorf near Berlin and receivers at Collm with the reflection point at 52.1°N, 13.2°E. This provides the possibility of comparing the results of different radar systems in nearly the same measuring volume. Meteor radar winds are generally stronger than the winds observed by MF and especially by LF radars. This difference is small near 80 km but increases with height. The difference between meteor radar and medium frequency radar winds is larger during winter than during summer, which might indicate an indirect influence of gravity waves on spaced antenna measurements.     

Gamma ray astrophysics and signatures of axion-like particles

We propose that axion-like particles (ALPs) with a two-photon vertex, consistent with all astrophysical and laboratory bounds, may lead to effects in the spectra of high-energy gamma-ray sources detectable by satellite or ground-based telescopes. We discuss two kinds of signatures: (i) a peculiar spectral depletion due to gamma rays being converted into ALPs in the magnetic fields of efficient astrophysical accelerators according to the “Hillas criterion”, such as jets of active galactic nuclei or hot spots of radio galaxies; (ii) an appearance of otherwise invisible sources in the GeV or TeV sky due to back-conversion of an ALP flux (associated with gamma-ray emitters suffering some attenuation) in the magnetic field of the Milky Way. These two mechanisms might also provide an exotic way to avoid the exponential cutoff of very high energy gamma-rays expected due to the pair production onto the extragalactic background light.