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Lewis Stephen Ramsdell
Lewis Stephen Ramsdell (4 June 1895 – 14 June 1975) was an American mineralogist who was a pioneer in the use of X-ray diffraction to study mineral structures. Education and career Ramsdell was born in Clinton, Michigan to Dwight and Phoebe Voorhies Ramsdell. He received a BS (1917) from the University of Michigan followed by an MS (1919) and a doctorate (1925). His doctoral work was on the structure of metallic sulphide minerals using X-ray diffraction. He set up the apparatus using a modified dental X-ray system after training in England in 1933 at the University of Manchester. He became an instructor in mineralogy at the University of Michigan, assistant professor (1926), and full professor in 1944. He trained several generations of X-ray crystallographers, was an advisor for Newman Thibault who studied silicon carbide, which became a major area of interest for Ramsdell. He determined the pattern of polytypes in silicon carbides and predicted several arrangements. He als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Michigan
, mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As of October 25, 2021. , president = Santa Ono , provost = Laurie McCauley , established = , type = Public research university , academic_affiliations = , students = 48,090 (2021) , undergrad = 31,329 (2021) , postgrad = 16,578 (2021) , administrative_staff = 18,986 (2014) , faculty = 6,771 (2014) , city = Ann Arbor , state = Michigan , country = United States , coor = , campus = Midsize City, Total: , including arboretum , colors = Maize & Blue , nickname = Wolverines , sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples " bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. Meteorites that are recovered after being observed as they transit the atmosphere and impact the Earth are called meteorite falls. All others are known as meteorite finds. Meteorites have traditionally been divided into three broad categories: stony meteorites that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Michigan Alumni
A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which roughly means "community of teachers and scholars". Universities typically offer both undergraduate and postgraduate programs. The first universities in Europe were established by Catholic Church monks. The University of Bologna (), Italy, which was founded in 1088, is the first university in the sense of: *being a high degree-awarding institute. *using the word ''universitas'' (which was coined at its foundation). *having independence from the ecclesiastic schools and issuing secular as well as non-secular degrees (with teaching conducted by both clergy and non-clergy): grammar, rhetoric, logic, theology, canon law, notarial law.Hunt Janin: "The university in medieval life, 1179–1499", McFarland, 2008, , p. 55f.de Ridder-Symoens, Hil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Crystallographers
American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, people who self-identify their ancestry as "American" ** American English, the set of varieties of the English language native to the United States ** Native Americans in the United States, indigenous peoples of the United States * American, something of, from, or related to the Americas, also known as "America" ** Indigenous peoples of the Americas * American (word), for analysis and history of the meanings in various contexts Organizations * American Airlines, U.S.-based airline headquartered in Fort Worth, Texas * American Athletic Conference, an American college athletic conference * American Recordings (record label), a record label previously known as Def American * American University, in Washington, D.C. Sports teams Soccer * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1975 Deaths
It was also declared the '' International Women's Year'' by the United Nations and the European Architectural Heritage Year by the Council of Europe. Events January * January 1 - Watergate scandal (United States): John N. Mitchell, H. R. Haldeman and John Ehrlichman are found guilty of the Watergate cover-up. * January 2 ** The Federal Rules of Evidence are approved by the United States Congress. ** Bangladesh revolutionary leader Siraj Sikder is killed by police while in custody. ** A bomb blast at Samastipur, Bihar, India, fatally wounds Lalit Narayan Mishra, Minister of Railways. * January 5 – Tasman Bridge disaster: The Tasman Bridge in Hobart, Tasmania, Australia, is struck by the bulk ore carrier , killing 12 people. * January 7 – OPEC agrees to raise crude oil prices by 10%. * January 10– February 9 – The flight of ''Soyuz 17'' with the crew of Georgy Grechko and Aleksei Gubarev aboard the ''Salyut 4'' space station. * January 15 – Alvor Agreemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1895 Births
Events January–March * January 5 – Dreyfus affair: French officer Alfred Dreyfus is stripped of his army rank, and sentenced to life imprisonment on Devil's Island. * January 12 – The National Trust for Places of Historic Interest or Natural Beauty is founded in England by Octavia Hill, Robert Hunter (National Trust), Robert Hunter and Canon Hardwicke Rawnsley. * January 13 – First Italo-Ethiopian War: Battle of Coatit – Italian forces defeat the Ethiopians. * January 17 – Félix Faure is elected President of the French Republic, after the resignation of Jean Casimir-Perier. * February 9 – Mintonette, later known as volleyball, is created by William G. Morgan at Holyoke, Massachusetts. * February 11 – The lowest ever UK temperature of is recorded at Braemar, in Aberdeenshire (historic), Aberdeenshire. This record is equalled in 1982#January, 1982, and again in 1995#December, 1995. * February 14 – Oscar Wilde's last pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ramsdellite
Ramsdellite (Mn4+O2) is an orthorhombic manganese dioxide mineral. It is relatively uncommon, and is usually found in deposits containing other manganese oxide crystals. Name Ramsdellite is named after the American mineralogist, Lewis Stephen Ramsdell (1895–1975). Ramsdell spent almost all his career at the University of Michigan as a professional mineralogist. Ramsdellite was one of the new phases he first recognized in the "black manganese oxide" minerals. It was later named in his honour by Michael Fleischer and W. E. Richmond, who fully described the mineral in 1943. The mineral is also called Groutellite. Chemistry and crystallography The chemical formula for Ramsdellite is MnO2. The empirical formula is Mn4+O2. Ramsdellite has the same chemistry as the more common pyrolusite, but is orthorhombic where pyrolusite is tetragonal. Ramsdellite belongs to the Orthorhombic crystal system and Dipyramidal crystal class. Properties: Classification The Dana classification is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a medium but is characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density of the medium. For the purpose of comparison, in supersonic flows, additional increased expansion may be achieved through an expansion fan, also known as a Prandtl–Meyer expansion fan. The accompanying expansion wave may approach and eventually collide and recombine with the shock wave, creating a process of destructive interference. The sonic boom associated with the passage of a supersonic aircraft is a type of sound wave produced by constructive interference. Unlike solitons (another kind of nonlinear wave), the energy and speed of a shock wave alone dissipates relatively quickly with distance. When a shock wave passes thr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coesite
Coesite is a form (polymorph) of silicon dioxide Si O2 that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (), are applied to quartz. Coesite was first synthesized by Loring Coes Jr., a chemist at the Norton Company, in 1953.The word "coesite" is pronounced as "Coze-ite" after chemist Loring Coes Jr. Occurrences In 1960, a natural occurrence of coesite was reported by Edward C. T. Chao, in collaboration with Eugene Shoemaker, from Barringer Crater, in Arizona, US, which was evidence that the crater must have been formed by an impact. After this report, the presence of coesite in unmetamorphosed rocks was taken as evidence of a meteorite impact event or of an atomic bomb explosion. It was not expected that coesite would survive in high pressure metamorphic rocks. In metamorphic rocks, coesite was initially described in eclogite xenoliths from the mantle of the Earth that were carried up by ascending magmas; kimberlite is the most commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ramsdell Notation
Ramsdell is a small village in the civil parish of Wootton St Lawrence with Ramsdell, in the Basingstoke and Deane district, in the English county of Hampshire. Ramsdell neighbours with Charter Alley only 1/2 mile up the road. The town of Tadley is away with the nearest shops. Ramsdell lies near other towns the largest being Basingstoke (7 miles) with Newbury only in the other direction. Other nearby villages include West Heath, Stoney Heath, Baughurst, Monk Sherborne, and Wootton St Lawrence. Village life Ramsdell is a typical English village with the church traditionally being the main focal point and also with a cricket ground, village hall and a community tennis court located by the cricket ground along with a children's play park. The focal point of the village is the cross roads right in the centre where Basingstoke Road meets Ewhurst Lane and Monk Sherborne road. Christ Church is located on one of the corners with the village hall nearby. Events in Ramsdell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphism (materials Science)
In materials science, polymorphism describes the existence of a solid material in more than one form or crystal structure. Polymorphism is a form of isomerism. Any crystalline material can exhibit the phenomenon. Allotropy refers to polymorphism for chemical elements. Polymorphism is of practical relevance to pharmaceuticals, agrochemicals, pigments, dyestuffs, foods, and explosives. According to IUPAC, a polymorphic transition is "A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point) to another phase of the same chemical composition with a different crystal structure." According to McCrone, polymorphs are "different in crystal structure but identical in the liquid or vapor states." Materials with two polymorphs are called dimorphic, with three polymorphs, trimorphic, etc. Examples Many compounds exhibit polymorphism. It has been claimed that "every compound has different polymorphic forms, and that, in general, the nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Natural occurrence Naturally occurring moissanite is found in only minute quantities in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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