Effect-specific analysis of propagation parameters

Results of propagation measurements with the satellite OLYMPUS carried out at 12.5, 20, and 30 GHz at the Research Center of the Deutsche Bundespost Telekom are discussed. In particular, attenuation, scintillation, and depolarization measurements are analyzed with special emphasis on frequency scaling of the various effects

Reducing Corrosion of Additive Manufactured Magnesium Alloys by Interlayer Ultrasonic Peening

Additive manufad (AM) magn alloys corrode rapidly due to tensile stress and coarse microstructures. Cyclically combining (hybridizing) additive manufacturing with interlayer ultrasonic peening was proposed as a solution to improve corrosion resistance of additive manufactured magnesium WE43 alloy through strengthening mechanisms and compressive residual stress. Applying interlayer peening work hardened discrete layers and formed a glocal integrity of regional grain refinement and subsurface compressive residual stress barriers. Tensile residual stress that typically accelerates corrosion decreased 90%. Results showed time-resolved control over corrosion was attainable by interlayer peening, and local corrosion within print cells decreased 57% with respect to as-printed WE43

Polarisation independence of amplitude scintillation

Otung and Evans presented some results of slant path scintillation measurements from Sparsholt (UK) which indicate that tropospheric scintillation is dependent on polarisation angle. However, results from Kirkkonummi (Finland), Lessive (Belgium) and Darmstadt (Germany), which are presented, do not show any significant polarisation dependence. The theoretical basis given by Otung and Evans is studied further, showing that tropospheric scintilation is not expected to be significantly influenced by polarisation angle