A chevron in geology is a sharply-folded rock formation. Chevron folds are regular folded beds with straight limbs and sharp hinges. Well developed, these folds produce a set of v-shaped beds.
They develop in response to compressive stress. The angles of the folds are generally 60 degrees or less. Chevron folding is helped if the bedding alternates between beds of different make-up. Turbidites, with alternating sandstones and shales, are the typical geological setting for chevron folds to occurs.
Chevrons can also form in land deposits, especially where there are sand dunes.
Meteorite strewnfield
A meteorite strewnfield is the area where meteorites and glassy tektites from a single meteor fall are found.
There are two ways for strewnfields to form:
Rifling
Rifling consists of spiral grooves cut into the inside of a barrel of a gun. It causes the bullet or projectile to spin as it flies through the air. This greatly improves the accuracy of the bullet over longer distances. The first muskets to use this technology were called rifles. Barrels are rifled using a left or right twist. The number of turns per inch is called the "twist rate". These are expressed as a ratio. For example, a 1:7 twist means the bullet will turn once for each seven inches of barrel length. As a general rule, the heavier the bullet, the higher the twist rate.
Gaspard Kollner, a 15th century gunmaker in Vienna, is thought by many to have invented rifling. Others think it was Augustus Kotter of Nuremberg who invented rifling in about 1520. At about that same time some crossbows fired a bolt (short heavy arrow) through a tube with spiral grooving. This gave the bolt more stability in flight. Whether these were used before rifling in gun barrels is not certain.
The "hand cannon" was first used in China in 1288. From this early beginning and a number of different guns, the smoothbore Musket was in use in Europe by the 15th century. While it could not fire and reload as fast as an archer and could not be reloaded on horseback, it could penetrate armor. Its greatest advantage over the bow was that anyone could learn to fire a musket in a very short period of time. It took much longer to properly train an archer. The British army used the musket along with pikemen until about 1705 when the pikes were abandoned. In 1722 the army adopted a standard musket called the Brown Bess and continued to use it until about the 1830s. Muskets used a round cast ball that was smaller in diameter than the gun barrel. As a consequence, when the musket was fired, the ball bounced along the inside the barrel. When it exited the barrel it could take a variety of paths making the musket inaccurate. So soldiers were massed together very closely and fired in volly (all at the same time). This sent bullets flying generally in the direction of the enemy on the theory that at least some of the bullets would hit some of the soldiers. The smoke from repeated vollies prevented soldiers from seeing what they were shooting at. In the heat of battle, soldiers who wanted reload and fire faster sometimes omitted ramming the bullet and powder into the barrel with the ramrod. Instead, they would try to seat the ball by sharply hitting the butt of the musket on the ground. This reduced the effectiveness even more. Sometimes the bullet would do little more than dribble out of the barrel and travel only a short distance.
The use of rifled muskets called rifles, changed this. During the American Revolutionary War Americans used muskets. But they also had marksmen who used their Kentucky rifles. The longer barrel was rifled for accuracy at a long range. American riflemen began targeting British officers in battle instead of just individual soldiers. Without their officers giving them every command, the British soldiers could not function as a unit. The British command despised the tactic calling it “unsportsmanlike”. But the Americans continued the practice up to the end of the war.
In 1849, a French army officer, Claude-Étienne Minié, invented a bullet with a hollow base named for him called the Minié ball. When fired, the bullet expanded to fit the rifling inside the gun barrel. This gave it even greater accuracy over a longer distance. The British used it in the Crimean War against Russian forces with tremendous success. At the time of the American Civil War, both the Union and the Confederate armies were using smoothbore muskets out of necessity. But soon rifled muskets using the Minié ball replaced the smoothbore muskets. The effects were to devastate the opposing army at much longer distances.
Most firearms produced today use a rifled barrel. There are basically three machining processes used to produce rifled barrels.
Interlaken (district)
The district of Interlaken in the Swiss canton of Bern has 23 municipalities in an area of 724 km².
Province of Tocopilla
The Province of Tocopilla () is one of three provinces of the northern Chilean region of Antofagasta (II). The provincial capital is Tocopilla.
The Tocopilla province has an area of .
The province is bordered on the north by the Tarapacá region, on the east by the El Loa province, on the south by the Antofagasta province and on the west by the Pacific Ocean.
(last national census), there were 31,516 people living in the province, giving it a population density of inhabitants/km².
The largest city of the province is Tocopilla, its capital, with a population, in 2002, of 23,352 inhabitants.
As a province, the Tocopilla province is a second-level administrative division, consisting of two communes ("comunas"). The city of Tocopilla serves as the provincial capital. The province is administered by a governor.
Konolfingen (district)
The district of Konolfingen in the Swiss canton of Bern has 29 municipalities in an area of 214 km².
Laupen (district)
The district of Laupen in the Swiss canton of Bern has 11 municipalities in an area of 88 km².
Moutier (district)
The district of Moutier in the Swiss canton of Bern has 26 municipalities in an area of 216 km².
La Neuveville (district)
The district of La Neuveville in the Swiss canton of Bern has 5 municipalities in an area of 59 km².
Nidau (district)
The district of Nidau in the Swiss canton of Bern has 25 municipalities in an area of 88 km².
List of programs broadcast by Cartoon Network
This is a list of pilot episodes on Cartoon Network, along with their premiere dates for each.
This is a list of pilot movies on Cartoon Network, along with their status and premiere dates for each.
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Frederick McDonald
Frederick Albert McDonald (c. 1872? April 1926) was an Australian politician and possible murder victim.
McDonald studied at the University of Sydney. He became a teacher, and rose to become President of the Teachers Federation of New South Wales. In 1922 he stood for election to the Australian House of Representatives, and won the new seat of Barton for the Labor Party. His main opponent was Hector Lamond, who had been the Nationalist member for the abolished seat of Illawarra.
In the 1925 election, McDonald was narrowly defeated by Nationalist candidate Thomas Ley. McDonald took the result to court, claiming that Ley had tried to bribe him, asking him not to put in his nomination papers. However, on 15 April 1926 McDonald disappeared on his way to a meeting with New South Wales Premier Jack Lang. They were planning to have the election result declared void. Neither McDonald's body nor his brief case were ever found.
Thomas Ley was found guilty of murder in England, but it was decided he was insane. He was sent to Broadmoor Hospital, where he died. It is believed that Ley was responsible for McDonald's disappearance. He is also suspected of being involved in the suspicious deaths of other of his political opponents.
Aster Yohannes