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🔗 London 🔗 Holidays 🔗 Christianity 🔗 River Thames 🔗 Christianity/Christmas

The River Thames frost fairs were held on the tideway of the River Thames in London, England in some winters, starting at least as early as the late 7th century all the way until the early 19th century. Most were held between the early 17th and early 19th centuries during the period known as the Little Ice Age, when the river froze over most frequently. During that time the British winter was more severe than it is now, and the river was wider and slower, further impeded by the medieval Old London Bridge.

Even at its peak, in the mid-17th century, the Thames in London froze less often than modern legend sometimes suggests, never exceeding about one year in ten except for four winters between 1649 and 1666. From 1400 until the removal of the medieval London Bridge in 1835, there were 24 winters in which the Thames was recorded to have frozen over at London; if "more or less frozen over" years (in parentheses) are included, the number is 26: 1408, 1435, 1506, 1514, 1537, 1565, 1595, 1608, 1621, 1635, 1649, 1655, 1663, 1666, 1677, 1684, 1695, 1709, 1716, 1740, (1768), 1776, (1785), 1788, 1795, and 1814. Of the 24, the numbers in each century were: 15th two, 16th five, 17th ten, 18th six, 19th one. The Thames freezes over more often upstream, beyond the reach of the tide, especially above the weirs, of which Teddington Lock is the lowest. The last great freeze of the higher Thames was in 1962–63.

Frost fairs were a rare event even in the coldest parts of the Little Ice Age. Some of the recorded frost fairs were in 695, 1608, 1683-4, 1716, 1739–40, 1789, and 1814. Recreational cold weather winter events were far more common elsewhere in Europe, for example in the Netherlands. These events in other countries as well as the winter festivals and carnivals around the world in present times can also be considered frost fairs. However, very few of them have actually used that title.

During the Great Frost of 1683–84, the severest frost recorded in England, the Thames was completely frozen for two months, with the ice reaching a thickness of 11 inches (28 cm) in London. Solid ice was reported extending for miles off the coasts of the southern North Sea (England, France and the Low Countries), causing severe problems for shipping and preventing the use of many harbours.

🔗 United States 🔗 Film 🔗 Film/American cinema 🔗 Science Fiction 🔗 United States/Texas

Primer is a 2004 American science fiction film about the accidental discovery of time travel. The film was written, directed, produced, edited and scored by Shane Carruth, who also stars with David Sullivan.

Primer is of note for its extremely low budget, experimental plot structure, philosophical implications, and complex technical dialogue, which Carruth, a college graduate with a degree in mathematics and a former engineer, chose not to simplify for the sake of the audience. The film collected the Grand Jury Prize at the 2004 Sundance Film Festival, before securing a limited release in the United States, and has since gained a cult following.

A rotary woofer is a subwoofer-style loudspeaker which reproduces very low frequency content by using a conventional speaker voice coil's motion to change the pitch (angle) of the blades of an impeller rotating at a constant speed. The pitch of the fan blades is controlled by the audio signal presented to the voice coil, and is able to swing both positive and negative, with respect to a zero pitch spinning blade position. Since the audio amplifier only changes the pitch of the blades, it takes much less power, per dB of generated acoustic sound level, to drive a rotary woofer than to power a conventional subwoofer, which uses a moving electromagnet (voice coil) placed within the field of a stationary permanent magnet to drive a cone which then displaces air. Rotary woofers excel at producing sounds below 20 Hz, below the normal hearing range; when installed in the wall of a sealed room, they can produce audio frequencies down to 0 Hz, a static pressure differential, by simply compressing the air in the sealed room.

🔗 Chemicals

Aluminium oxynitride (marketed under the name ALON by Surmet Corporation) is a transparent ceramic composed of aluminium, oxygen and nitrogen. ALON is optically transparent (≥ 80%) in the near-ultraviolet, visible, and midwave-infrared regions of the electromagnetic spectrum. It is four times as hard as fused silica glass, 85% as hard as sapphire, and nearly 115% as hard as magnesium aluminate spinel. Since it has a cubic spinel structure, it can be fabricated to transparent windows, plates, domes, rods, tubes, and other forms using conventional ceramic powder processing techniques.

ALON is the hardest polycrystalline transparent ceramic available commercially. Because of its relatively low weight, distinctive optical and mechanical properties, and resistance to oxidation or radiation, it shows promise for applications such as bulletproof, blast-resistant, and optoelectronic windows. ALON-based armor has been shown to stop multiple armor-piercing projectiles of up to .50 BMG.

ALON is commercially available in sizes as large as 18-by-35-inch (460 mm × 890 mm; 46 cm × 89 cm) monolithic windows.

🔗 Physics 🔗 Greece 🔗 Food and drink 🔗 Spirits

The ouzo effect (also louche effect and spontaneous emulsification) is a milky (louche) oil-in-water emulsion that is formed when water is added to ouzo and other anise-flavored liqueurs and spirits, such as pastis, rakı, arak, sambuca and absinthe. Such emulsions occur with only minimal mixing and are highly stable.

🔗 United States/U.S. Government 🔗 United States 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Law 🔗 United States History 🔗 U.S. Congress 🔗 Military history/National militaries 🔗 Vietnam 🔗 Project-independent assessment

The War Powers Resolution (also known as the War Powers Resolution of 1973 or the War Powers Act) (50 U.S.C. ch. 33) is a federal law intended to check the U.S. president's power to commit the United States to an armed conflict without the consent of the U.S. Congress. The resolution was adopted in the form of a United States congressional joint resolution. It provides that the president can send the U.S. Armed Forces into action abroad only by declaration of war by Congress, "statutory authorization", or in case of "a national emergency created by attack upon the United States, its territories or possessions, or its armed forces".

The bill was introduced by Clement Zablocki, a Democratic congressman representing Wisconsin's 4th district. The bill had bipartisan support and was co-sponsored by a number of U.S. military veterans. The War Powers Resolution requires the president to notify Congress within 48 hours of committing armed forces to military action and forbids armed forces from remaining for more than 60 days, with a further 30-day withdrawal period, without congressional authorization for use of military force (AUMF) or a declaration of war by the United States. The resolution was passed by two-thirds each of the House and Senate, overriding the veto of President Richard Nixon.

It has been alleged that the War Powers Resolution has been violated in the past. However, Congress has disapproved all such incidents, and no allegations have resulted in successful legal actions taken against a president.

🔗 Professional sound production

The phonautograph is the earliest known device for recording sound. Previously, tracings had been obtained of the sound-producing vibratory motions of tuning forks and other objects by physical contact with them, but not of actual sound waves as they propagated through air or other media. Invented by Frenchman Édouard-Léon Scott de Martinville, it was patented on March 25, 1857. It transcribed sound waves as undulations or other deviations in a line traced on smoke-blackened paper or glass. Intended solely as a laboratory instrument for the study of acoustics, it could be used to visually study and measure the amplitude envelopes and waveforms of speech and other sounds, or to determine the frequency of a given musical pitch by comparison with a simultaneously recorded reference frequency.

Apparently, it did not occur to anyone before the 1870s that the recordings, called phonautograms, contained enough information about the sound that they could, in theory, be used to recreate it. Because the phonautogram tracing was an insubstantial two-dimensional line, direct physical playback was impossible in any case.

Several phonautograms recorded before 1861 were successfully played as sound in 2008 by optically scanning them and using a computer to process the scans into digital audio files.

🔗 Biography 🔗 Biography/science and academia

Gorō Shimura (志村 五郎, Shimura Gorō, 23 February 1930 – 3 May 2019) was a Japanese mathematician and Michael Henry Strater Professor Emeritus of Mathematics at Princeton University who worked in number theory, automorphic forms, and arithmetic geometry. He was known for developing the theory of complex multiplication of abelian varieties and Shimura varieties, as well as posing the Taniyama–Shimura conjecture which ultimately led to the proof of Fermat's Last Theorem.

🔗 Military history 🔗 Architecture 🔗 Military history/Fortifications

Air raid shelters, also known as bomb shelters, are structures for the protection of non-combatants as well as combatants against enemy attacks from the air. They are similar to bunkers in many regards, although they are not designed to defend against ground attack (but many have been used as defensive structures in such situations).

Prior to World War II, in May 1924, an Air Raid Precautions Committee was set up in the United Kingdom. For years, little progress was made with shelters because of the apparently irreconcilable conflict between the need to send the public underground for shelter and the need to keep them above ground for protection against gas attacks. In February 1936 the Home Secretary appointed a technical Committee on Structural Precautions against Air Attack.

By November 1937, there had only been slow progress, because of a serious lack of data on which to base any design recommendations and the Committee proposed that the Home Office should have its own department for research into structural precautions, rather than relying on research work done by the Bombing Test Committee to support the development of bomb design and strategy. This proposal was eventually implemented in January 1939.

During the Munich crisis, local authorities dug trenches to provide shelter. After the crisis, the British Government decided to make these a permanent feature, with a standard design of precast concrete trench lining. Unfortunately these turned out to perform very poorly. They also decided to issue free to poorer households the Anderson shelter, and to provide steel props to create shelters in suitable basements.

🔗 Europe 🔗 Musical Instruments 🔗 Percussion

A pyrophone, also known as a "fire/explosion organ" or "fire/explosion calliope" is a musical instrument in which notes are sounded by explosions, or similar forms of rapid combustion, rapid heating, or the like, such as burners in cylindrical glass tubes, creating light and sound. It was invented by physicist and musician Georges Frédéric Eugène Kastner (born 1852 in Strasbourg, France – died 1882 in Bonn, Germany), son of composer Jean-Georges Kastner, around 1870.