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
Surface acoustic wave local oscillator has been mixed with the received signal, and so a filter with a fixed frequency and high Q provides excellent removal of unwanted or interference signals. In these applications, SAW filters are almost always used with a phase locked loop synthesized local oscillator, or a varicap driven oscillator. In seismology surface acoustic waves travelling along the Earth's surface play an important role, since they can be the most destructive type of seismic wave produced by earthquakes. In recent years, attention has been drawn to using SAWs to drive microfluidic actuation and a variety of other processes. Owing to