From: owner-ammf-digest@smoe.org (alt.music.moxy-fruvous digest) To: ammf-digest@smoe.org Subject: alt.music.moxy-fruvous digest V14 #8927 Reply-To: ammf@fruvous.com Sender: owner-ammf-digest@smoe.org Errors-To: owner-ammf-digest@smoe.org Precedence: bulk alt.music.moxy-fruvous digest Saturday, May 7 2022 Volume 14 : Number 8927 Today's Subjects: ----------------- Congrats! You've received a Home Depot reward ["Online Survey" Subject: Congrats! You've received a Home Depot reward Congrats! You've received a Home Depot reward http://yokoplus.us/9_7aPtM84_iO3JbpvwGdr6yyd6GDTKW4yePqR5b0oX1whszG0w http://yokoplus.us/iPr9g7nX43XR9-F5RpGS7DvnRfo2NiGufsolYD3GIAUX3iFSGA Abundant barchan dunes may merge into barchanoid ridges, which then grade into linear (or slightly sinuous) transverse dunes, so called because they lie transverse, or across, the wind direction, with the wind blowing perpendicular to the ridge crest. Seif or longitudinal dunes Seif dunes are linear (or slightly sinuous) dunes with two slip faces. The two slip faces make them sharp-crested. They are called seif dunes after the Arabic word for "sword". They may be more than 160 kilometres (100 miles) long, and thus easily visible in satellite images (see illustrations). Seif dunes are associated with bidirectional winds. The long axes and ridges of these dunes extend along the resultant direction of sand movement (hence the name "longitudinal"). Some linear dunes merge to form Y-shaped compound dunes. Formation is debated. Ralph Bagnold, in The Physics of Blown Sand and Desert Dunes, suggested that some seif dunes form when a barchan dune moves into a bidirectional wind regime, and one arm or wing of the crescent elongates. Others suggest that seif dunes are formed by vortices in a unidirectional wind. In the sheltered troughs between highly developed seif dunes, barchans may be formed, because the wind is constrained to be unidirectional by the dunes ------------------------------ End of alt.music.moxy-fruvous digest V14 #8927 **********************************************