Sastrugi breaking equipment—ripples and waves are often undercut and the surface is hard and unforgiving, with constant minor topographic changes between ridge and trough. The words "sastrugi" and "zastrugi" are Russian-language plurals; the singular is "sastruga" or "zastruga". The form "sastruga" started as the German-language transliteration of the Russian word заструга (plural: заструги). A Latin-type analogica singular "sastrugus" is used in various writings on exploration of the South Pole, including Robert Falcon Scott's expedition's diaries and Ernest Shackleton's "The Heart of the Antarctic". Under the action of steady wind, free snow particles accumulate and drift like the sand grains in barchan
Spherical surface acoustic wave (SAW) sensor Spherical surface acoustic wave (SAW) sensor Spherical surface acoustic wave sensors use a type of surface acoustic wave (SAW) that travels along the surface of a medium exhibiting elasticity with exponentially decaying amplitude along depth. MEMS-IDT technology allows the use of SAW waves to sense various gases. Sensitivity up to 10 ppm of hydrogen using a spherical Ball SAW device is obtained. Conventional planar SAW sensors are based on principle that the parameters such as amplitude, speed and phase of Surface acoustic wave changes on adsorption of gas molecules. Limitation of planar SAW based sensors is that the change in