"Signal" search for intelligence in the galactic nucleus with the array of the Lowlands

In August, 1981, the Westerbork Synthesis Radio Telescope was used for 4 h to search for narrowband pulsing radio beacons in the direction of the Galactic Center. By using both the spatial discrimination and temporal stability available to an interferometric measurement, weak intermittent signals can be detected even in the face of the strong, naturally caused radiation from this region. A radio beacon within our bandwidth, centered on the 21 cm neutral hydrogen line, would be recognizable if it had a repetition period between 40 sec and 1/2 h. The rms sensitivity to point sources was approximately 50 mJy/cycle, and the detection limit was 500 mJy/cycle. The limit degrades for pulse widths < 0.02s. No repetitive signals were found. For a swept, narrow-band radio beacon constrained to the Galactic Disk (beamwidth = 0.02 rad), our detection limit corresponds to a transmitter power of 10(11) MW at the Galactic Center.     

The Apollo SWC Experiment: Results,Conclusions, Consequences

Space Science Reviews - The Apollo Solar Wind Composition (SWC) experiment was designed to measure elemental and isotopic abundances of the light noble gases in the solar wind, and to investigate...     

PARAMETER ANALYSIS ON CIRCULATION CONTROLLED CIRCULAR CYLINDER FOR NOTARTM TAIL BOOM

Lift on circulation control （CC） circular cylinder is calculated via numerical simulations based on 2D real- izable k-e epsilon viscous model and compared with experimental data. The simulation result shows an acceptable agreement with tested data. With the proved grid and simulation method, series of simulations are conducted to study the effect of parameters on lift. Single slotted tail booms under different clown wash velocities are optimized with the principle of generating maximum total moment around the main rotor shaft with same total power con- sumption. The results show that larger jet flow velocity, or smaller blow angle, or larger diameter of the cross section can help generating larger lift while enhancing the attachment of both the jet flow and down wash flow. Multiple slotted tail boom is better because it increases lift with same total slot width, and can increase lift by in- creasing total slot width without causing separation, also it helps generating high steady lift at a big rank of slot at- tack angles. To mount a guide vane （GV） at the exit of the slot, or shape the upper slot wall like a smooth-GV, or design the slot with an edge fillet is not recommended because it reduces the velocity of both the jet flow and the upstream of the attached downwash flow. Compared with other shapes of the slots, arcs-profiled slot performs better because of larger jet flow velocity and smaller blow angle. In order to generate the largest moment with same total power consumed by the entire NOTARTM system, total width of the slots and slot attack angle should be optimized according to velocity of down wash flow.     

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.