Investigation of natural environment by space means. Geobotany, Geomorphology, soil sciences, agricultural lands, landscape study

Reports given by Soviet specialists at a meeting of Socialist countries on remote sensing of the earth using aerospace methods are presented

Nilpotents Leave No Trace: A Matrix Mystery for Pandemic Times

Reopening a cold case, Inspector Echelon, high-ranking in the Row Operations Center, is searching for a lost linear map, known to be nilpotent. When a partially decomposed matrix is unearthed, he reconstructs its reduced form, finding it singular. But were its origins nilpotent

Photovoltage in curved 1D systems

Curvature of quantum wire results in intrasubband absorption of IR radiation that induces stationary photovoltage in presence of circular polarization. This effect is studied in ballistic (collisionless) and kinetic regimes. The consideration is concentrated on quantum wires with curved central part. It is shown, that if mean free path is shorter than length of the curved part the photovoltage does not depend on the wire shape, but on the total angle of rotation of wire tangent. It is not the case when mean free path is finite or large. This situation was studied for three specific shapes of wires: "hard angle", "open book" and "$\Omega$-like".Comment: 12 pages, 1 figur

Thermal stress response of General Purpose Heat Source (GPHS) aeroshell material

A thermal stress test was conducted to determine the ability of the GPHS aeroshell 3 D FWPF material to maintain physical integrity when exposed to a severe heat flux such as would occur from prompt reentry of GPHS modules. The test was performed in the Giant Planetary Facility at NASA's Ames Research Center. Good agreement was obtained between the theoretical and experimental results for both temperature and strain time histories. No physical damage was observed in the test specimen. These results provide initial corroboration both of the analysis techniques and that the GPHS reentry member will survive the reentry thermal stress levels expected