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🔗 Physics

An electret (formed of as a portmanteau of electr- from "electricity" and -et from "magnet") is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fields, and is the electrostatic equivalent of a permanent magnet. Although Oliver Heaviside coined this term in 1885, materials with electret properties were already known to science and had been studied since the early 1700s. One particular example is the electrophorus, a device consisting of a slab with electret properties and a separate metal plate. The electrophorus was originally invented by Johan Carl Wilcke in Sweden and again by Alessandro Volta in Italy.

The name derives from "electron" and "magnet"; drawing analogy to the formation of a magnet by alignment of magnetic domains in a piece of iron. Historically, electrets were made by first melting a suitable dielectric material such as a polymer or wax that contains polar molecules, and then allowing it to re-solidify in a powerful electrostatic field. The polar molecules of the dielectric align themselves to the direction of the electrostatic field, producing a dipole electret with a permanent electrostatic bias. Modern electrets are usually made by embedding excess charges into a highly insulating dielectric, e.g. by means of an electron beam, corona discharge, injection from an electron gun, electric breakdown across a gap, or a dielectric barrier.

🔗 Film 🔗 Film/American cinema

The Black Maria ( mə-RY-ə) was Thomas Edison's film production studio in West Orange, New Jersey. It was the world's first film studio.

🔗 Canada 🔗 Politics 🔗 Canada/Quebec 🔗 Canada/Political parties and politicians in Canada

The Quebec sovereignty movement (French: Mouvement souverainiste du Québec) is a political movement whose objective is to achieve the sovereignty of Quebec, a province of Canada since 1867, including in all matters related to any provision of Quebec's public order that is applicable on its territory. Sovereignists suggest that the people of Quebec make use of their right to self-determination – a principle that includes the possibility of choosing between integration with a third state, political association with another state or independence – so that Quebecois, collectively and by democratic means, give themselves a sovereign state with its own independent constitution.

Quebec sovereignists believe that with such a sovereign state, the Quebec nation will be better equipped to promote its own economic, social, ecological and cultural development. Quebec's sovereignist movement is based on Quebec nationalism.

🔗 United States 🔗 Organized Labour 🔗 Record Labels 🔗 United States/American music

On August 1, 1942, the American Federation of Musicians, at the instigation of union president James C. Petrillo, began a strike against the major American record companies because of disagreements over royalty payments. Beginning at midnight, July 31, 1942, no union musician could make commercial recordings for any commercial record company. That meant that a union musician was allowed to participate on radio programs and other kinds of musical entertainment, but not in a recording session. The 1942–1944 musicians' strike remains the longest strike in entertainment history.

The strike did not affect musicians performing on live radio shows, in concerts, or, after October 27, 1943, on special recordings made by the record companies for V-Discs for distribution to the armed forces fighting World War II, because V-Discs were not available to the general public. However, the union did frequently threaten to withdraw musicians from the radio networks to punish individual network affiliates who were deemed "unfair" for violating the union's policy on recording network shows for repeat broadcasts.

The strike had a major impact on the American musical scene. At the time, union bands dominated popular music; after the strike, and partly as a result of it, the big bands began to decline and vocalists began to dominate popular music.

🔗 Technology 🔗 Lists 🔗 Electronics

This is a list of sensors sorted by sensor type.

🔗 Philosophy 🔗 Philosophy/Logic

The Texas sharpshooter fallacy is an informal fallacy which is committed when differences in data are ignored, but similarities are overemphasized. From this reasoning, a false conclusion is inferred. This fallacy is the philosophical or rhetorical application of the multiple comparisons problem (in statistics) and apophenia (in cognitive psychology). It is related to the clustering illusion, which is the tendency in human cognition to interpret patterns where none actually exist.

The name comes from a joke about a Texan who fires some gunshots at the side of a barn, then paints a shooting target centered on the tightest cluster of hits and claims to be a sharpshooter.

🔗 Neuroscience 🔗 Physiology

The gunslinger effect, also sometimes called Bohr's law or the gunfighter's dilemma, is a psychophysical theory which says that an intentional or willed movement is slower than an automatic or reaction movement. The concept is named after physicist Niels Bohr, who first deduced that the person who draws second in a gunfight will actually win the shoot-out.

🔗 Mining 🔗 South Africa

Mponeng is a gold mine in South Africa's Gauteng province. Previously known as Western Deep Levels #1 Shaft, the underground and surface works were commissioned in 1987. It extends over 4 kilometres (2.5 mi) below the surface, and is considered to be one of the most substantial gold mines in the world. It is also currently the world's deepest mine from ground level, reaching a depth of 4 km (2.5 mi) below ground level. The trip from the surface to the bottom of the mine takes over an hour.

Over 5400 metric tonnes of rock are excavated from Mponeng each day. At a price of $19.4 per gram of gold, the mine only needs to extract 10 grams of gold per ton excavated to remain profitable. The mine contains at least two gold reefs, with the deepest one metre thick.

Harmony Gold purchased Mponeng from AngloGold Ashanti in September 2020. Along with AGA's Mine Waste Solutions, Harmony paid approximately $300m.

🔗 Biography 🔗 France 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Biography/arts and entertainment 🔗 Christianity 🔗 Catholicism 🔗 Middle Ages/Crusades 🔗 Military history/Crusades 🔗 Belgium 🔗 Christianity/Christianity in China

William of Rubruck (Dutch: Willem van Rubroeck, Latin: Gulielmus de Rubruquis; fl. 1248–1255) was a Flemish Franciscan missionary and explorer.

He is best known for his travels to various parts of the Middle East and Central Asia in the 13th century, including the Mongol Empire. His account of his travels is one of the masterpieces of medieval travel literature, comparable to those of Marco Polo and Ibn Battuta.

🔗 Graphic design

Corporate Memphis is a term used (often disparagingly) to describe a flat, geometric art style, widely used in Big Tech illustrations in the late 2010s and early 2020s. It is often criticized as seeming uninspired and dystopian.