Certain conditions help the formation of dust devils:
1. Flat barren, desert terrain: Flat terrain and hot conditions help the hot air "fuel" being always available. The dust and sand helps the dust devil be seen.
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2. Clear skies or lightly cloudy conditions: The surface needs a lot of solar energy to heat the air.
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3. Light or no wind, and cool temperature in the atmosphere: Without a cool atmosphere and hot surface, the dust devil with never form. Wind will not keep the dust devil stable.
A dust devil "dies" when it eventually sucks in cool air from the surface. Cool air destroys the dust devil because it quickly discourages the rising of air through the column. This usually happens when the dust devil becomes weak, or moves across a new terrain were the surface temperatures are cooler.
Similarly, when hot air rises rapidly in water bodies and if conditions are just right they are known as water sprout.
Dust devils occur on the planet of Mars as well. They can be ten times higher than ones on Earth, and fifty times as wide. They can pose a threat to technology placed on Mars.
However, not all dust devils are damaging. Mission members keeping an eye on the Mars Spirit rover reported that on March 12, 2005, a lucky encounter with a dust devil had cleaned the solar panels of that robot. Power levels dramatically increased, and much more scientific work was able to be done.
Samaritan Pentateuch
The Samaritan Pentateuch or Samaritan Torah is a special version of the Torah used by the Samaritans. This version was created at the latest 127 BC, when the Temple in Jerusalem was destroyed, and the Samaritans split from the other group in the Temple. As the name says, this version contains the first five books of Moses, or the Torah.
Scholars use the Samaritan Pentateuch when they want to find the meaning of words in the original Pentateuch or if they want to learn about the history of the different versions of the Bible. Some scrolls among the Dead Sea scrolls look like Samaritan Pentateuch.
Samaritan practices are based on their version of the Five Books of Moses, which is slightly different from the Masoretic text or the Greek Septuagint texts. Some differences are small, such as the ages of different people mentioned in genealogy, while others are major, such as the commandment to only have one wife which appears in the Samaritan text but not in the other versions. (See .)
Special importance is attached to the "Abisha Scroll", which is used in the Samaritan synagogue of Nablus. The Samaritans claim it was penned by Abishua, great-grandson of Aaron (), thirteen years after the entry into the land of Israel under the leadership of Joshua, son of Nun. But modern scholars have observed that the scroll appears to include work by different scribes from different centuries, with the oldest texts dating to the 12th century A.D.
John Jacob Astor
John Jacob Astor (July 17, 1763 – March 29, 1848), born Johann Jakob Astor, was a German-American businessman. He was born in Germany and moved to London and then to New York City in 1784. He started a business trading furs. By 1800, he had made half a million dollars trading furs. His company was called The Pacific Fur Trading Company. In the early 1800s, his company was trading furs in Oregon. His fur traders found the pass through which the Oregon Trail passes. He made even more money in New York real estate. When he died in 1848, he was worth over $50 million. Today, his fortune would be over $150 billion. The city of Astoria, Oregon was named for him. So was the neighborhood Astoria, Queens and Astor Place in Manhattan.
Pi bond
In chemistry, a pi bond (π bond) is a covalent chemical bonds where the orbital path of one electron crosses (overlaps) with the path of another. The electrons have a lobe shaped figure of eight path (see picture). There are two areas of overlap as the paths overlap on both lobes. Only one of the orbital's nodal planes passes through both of the involved nuclei.
The Greek letter π in their name refers to p orbitals. The orbital symmetry of the pi bond looks the same as the p orbital when seen down the bond axis. P orbitals usually have this sort of bonding. D orbitals are also assumed to use pi bonding but this is not necessarily what happens in reality. The idea of bonding d orbitals fits in with the theory of hypervalence.
Pi bonds are usually weaker than sigma bonds. Quantum mechanics says this is because the orbital paths are parallel so there is much less overlap between the p-orbitals.
Pi bonds happen when two atomic orbitals are in contact through two areas of overlap. Pi-bonds are more spread out bonds than the sigma bonds. Electrons in pi bonds are sometimes called pi electrons. Molecular fragments joined by a pi bond cannot rotate about that bond without breaking the pi bond. The rotation destroys the parallel paths of the two p orbitals.
Atoms that are joined by a double bond have one sigma bond and one pi bond. If they are joined by a triple bond they have one sigma bond and two pi bonds.
A pi bond is weaker than a sigma bond, but the combination of pi and sigma bond is stronger than either bond by itself. The extra strength of a multiple bond versus a single (sigma bond) is shown in many ways. The most obvious is a contraction in bond lengths. For example in organic chemistry, carbon-carbon bond lengths are in ethane (154 pm), in ethylene (134 pm) and in acetylene (120 pm). More bonds make the total bond shorter and stronger.
Electronic configuration is based on S,P,D,and f -Block.
S has 2 electrons
P has 6 electrons
D has 10 electrons
F has 14 electrons
Pi bonds do not necessarily join a pair of atoms that are also sigma-bonded.
In certain metal complexes, pi interactions between a metal atom and alkyne and alkene pi antibonding orbitals form pi-bonds.
In some cases of multiple bonds between two atoms, there is no sigma bond at all, only pi bonds. Examples include diiron hexacarbonyl (Fe(CO)), dicarbon (C) and the borane BH. In these compounds the central bond has only pi bonding. In order to get the most orbital overlap the bond distances are much shorter than expected.
Being and Time
Being and Time (, 1927) is a book that was written by the German philosopher Martin Heidegger. It is his best known book and is said to be one of the most important philosophical works of the 20th century. It has greatly influenced 20th-century philosophy, particularly existentialism, hermeneutics and deconstruction.
Supertec
Supertec was a Formula One engine supplier in 1999 and 2000. Supertec supplied engines that were designed by Renault F1. They took engines built by Mecachrome from the 1998 season, and updated them for 1999 and 2000. Supertec then put their name on the engines.
Chesil Beach
Chesil Beach, sometimes called Chesil Bank, in Dorset, southern England is one of three major shingle structures in Britain. Its name is derived from the Old English "ceosel" or "cisel", meaning "gravel" or "shingle".
It is a kind of offshore barrier which has joined the mainland with Portland Bill. The lagoon between the chesil and the mainland is called The Fleet or The Fleet Lagoon.
The shingle beach is 18 miles long (29km), 220 yards wide (200m) and 50 feet high (15m). The beach and the Fleet are part of the Jurassic Coast, a UNESCO World Heritage Site, and the location for a book, "On Chesil Beach" by Ian McEwan.
At the eastern end of the beach at the village of Chiswell, against the cliffs of the Isle of Portland, the beach curves round sharply to form Chesil Cove. This part of the beach protects the low-lying village from flooding. Westwards the shingle forms a straight line along the coast, enclosing the Fleet, a shallow tidal lagoon. The lagoon is 9½ feet (3m) at its deepest.
The beach provides shelter from the prevailing winds (from the west) and waves for the town of Weymouth and the village of Chiswell, which would otherwise probably not exist