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Friction

Friction is the force resisting the relative motion of solid surfaces, fluid layers, material elements sliding against each other. There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction between non-moving surfaces, kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction arises from the interaction of surface features, known as asperities Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. Internal friction is the force resisting motion between the elements making up a solid material while it undergoes deformation; when surfaces in contact move relative to each other, the friction between the two surfaces converts kinetic energy into thermal energy.

This property can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood together to start a fire. Kinetic energy is converted to thermal energy whenever motion with friction occurs, for example when a viscous fluid is stirred. Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. Friction is a component of the science of tribology. Friction is important in supplying traction to facilitate motion on land. Most land vehicles rely on friction for acceleration and changing direction. Sudden reductions in traction can cause loss of control and accidents. Friction is not itself a fundamental force. Dry friction arises from a combination of inter-surface adhesion, surface roughness, surface deformation, surface contamination; the complexity of these interactions makes the calculation of friction from first principles impractical and necessitates the use of empirical methods for analysis and the development of theory.

Friction is a non-conservative force - work done against friction is path dependent. In the presence of friction, some kinetic energy is always transformed to thermal energy, so mechanical energy is not conserved; the Greeks, including Aristotle and Pliny the Elder, were interested in the cause and mitigation of friction. They were aware of differences between static and kinetic friction with Themistius stating in 350 A. D. that "it is easier to further the motion of a moving body than to move a body at rest". The classic laws of sliding friction were discovered by Leonardo da Vinci in 1493, a pioneer in tribology, but the laws documented in his notebooks, were not published and remained unknown; these laws were rediscovered by Guillaume Amontons in 1699 and became known as Amonton's three laws of dry friction. Amontons presented the nature of friction in terms of surface irregularities and the force required to raise the weight pressing the surfaces together; this view was further elaborated by Bernard Forest de Bélidor and Leonhard Euler, who derived the angle of repose of a weight on an inclined plane and first distinguished between static and kinetic friction.

John Theophilus Desaguliers first recognized the role of adhesion in friction. Microscopic forces cause surfaces to stick together; the understanding of friction was further developed by Charles-Augustin de Coulomb. Coulomb investigated the influence of four main factors on friction: the nature of the materials in contact and their surface coatings. Coulomb further considered the influence of sliding velocity and humidity, in order to decide between the different explanations on the nature of friction, proposed; the distinction between static and dynamic friction is made in Coulomb's friction law, although this distinction was drawn by Johann Andreas von Segner in 1758. The effect of the time of repose was explained by Pieter van Musschenbroek by considering the surfaces of fibrous materials, with fibers meshing together, which takes a finite time in which the friction increases. John Leslie noted a weakness in the views of Amontons and Coulomb: If friction arises from a weight being drawn up the inclined plane of successive asperities, why isn't it balanced through descending the opposite slope?

Leslie was skeptical about the role of adhesion proposed by Desaguliers, which should on the whole have the same tendency to accelerate as to retard the motion. In Leslie's view, friction should be seen as a time-dependent process of flattening, pressing down asperities, which creates new obstacles in what were cavities before. Arthur Jules Morin developed the concept of sliding versus rolling friction. Osborne Reynolds derived the equation of viscous flow; this completed the classic empirical model of friction used today in engineering. In 1877, Fleeming Jenkin and J. A. Ewing investigated the continuity between static and kinetic friction; the focus of research during the 20th century has been to understand the physical mechanisms behind friction. Frank Philip Bowden and David Tabor showed that, at a microscopic level, the actual area of contact between surfaces is a small fraction of the apparent area; this actual area of contact, caused by asperities increases with pressure. The development of the atomic force

Francis T. Cullen

Francis Thomas Cullen, Jr. is an American criminologist and Distinguished Research Professor Emeritus at the University of Cincinnati's School of Criminal Justice. Born in Boston, Massachusetts in 1951, Cullen enrolled at Bridgewater State College in 1968, hoping to avoid getting drafted into the Vietnam War by getting a grade point average of 2.0 or higher. He graduated in 1972 with a B. A. in psychology. He received his M. A. and Ph. D. from Columbia University in 1974 and 1979, respectively. Both his graduate degrees were in education, he taught at Western Illinois University before joining the University of Cincinnati in 1982 as an associate professor. In 1987, he became a full professor at the University of Cincinnati, in 1993, he became a distinguished professor there, he became an emeritus professor at the University of Cincinnati in 2015. Cullen became a fellow of the Academy of Criminal Justice Sciences in 1989, served as its president from 1993 to 1994. In 1996, he received the ACJS's Bruce Smith, Sr. Award, followed by the Founders Award in 2002, making him one of only four people to receive all three of the ACJS's awards.

He served as president of the American Society of Criminology from 2003 to 2004. In 2010, he received the ASC's Edwin H. Sutherland Award. Cullen has served as editor-in-chief of two journals: Justice Quarterly, from 1987 to 1989, Journal of Crime and Justice, from 1984 to 1986. Faculty page Biography at Center for Problem-Oriented Policing Francis T. Cullen publications indexed by Google Scholar

Jeffrey Remedios

Jeffrey Remedios is the president of Universal Music Canada. He founded Arts & Crafts Records. In 2015 he was named by Toronto Life as one of Toronto's 50 most influential people. Remedios began his post-school career in music at Virgin Music Canada, holding various posts, including Media & Artist Relations, Digital Marketing, Director of National Promotion. In 2003, Jeffrey Remedios left EMI and launched Arts & Crafts Productions with Daniel Cutler and Kevin Drew; the goal of the new label was to create a vehicle to release and promote content from Kevin Drew's new group, Broken Social Scene. Under Remedios' leadership, Arts & Crafts Productions collected 21 Juno wins. On September 21, 2015, Universal Music Group CEO Lucian Grainge appointed Remedios as President and CEO of Universal Music Canada. Remedios serves on the Board of Directors of the Canadian Academy of Recording Arts and Sciences, Music Canada, the City of Toronto Music Advisory Council, the Toronto International Film Festival, the Canadian Opera Company, the Art Gallery of Ontario.

He graduated McMaster University in 1998 with a minor in Music. McMaster presented Remedios with its Alumni Gallery Award in 2013. In 2015 Remedios married Lucia Graca at a ceremony in Burl's Creek Event Grounds, site of the Wayhome and Boots And Hearts music festivals, their wedding reception included musical performances by several artists from the Arts & Crafts label. Toronto Life magazine named the couple among the city's Best Dressed in 2016

Nordiska Berlin

Nordiska Berlin was a German association football club from the city of Berlin. Established sometime in 1913, the team was part of the ATSB, a leftist national sports organization which organized a football competition and championship separate from that of the DFB. Nordiska took part in the ATSB championship in 1921, beating FT Breslau-Süd 2:1 in a quarterfinal match, before getting through the semifinal past FT Unterweser 3:2 in overtime, they lost the title match 0:3 VfL Leipzig-Südost. Under the Nazis, worker's clubs such as Nordiska were banned in 1933, alongside other clubs with political or religious affiliations. Following World War II, occupying Allied authorities banned organizations throughout the country, including sports and football clubs, as part of the process of de-Nazification. New clubs began to emerge shortly after the war and the former memberships of Nordiska and Berliner SC Normannia became part of Sportgruppe Nordost which, after the re-establishment of Normannia in 1950, gave rise to present-day club MSV Normannia 08.

Das deutsche Fußball-Archiv historical German domestic league tables

Makinti Napanangka

Makinti Napanangka was a Pintupi-speaking Indigenous Australian artist from Australia's Western Desert region. She was referred to posthumously as Kumentje; the term Kumentje was used instead of her personal name as it is customary among many indigenous communities not to refer to the deceased by their original given name for some time after their death. She lived in the communities of Haasts Bluff, at Kintore, about 50 kilometres north-east of the Lake MacDonald region where she was born, on the border of the Northern Territory and Western Australia. Makinti Napanangka began painting Contemporary Indigenous Australian art at Kintore in the mid-1990s, encouraged by a community art project. Interest in her work developed and she is now represented in most significant Australian public art galleries, including the National Gallery of Australia. A finalist in the 2003 Clemenger Contemporary Art Award, Makinti won the National Aboriginal & Torres Strait Islander Art Award in 2008, her work was shown in the major indigenous art exhibition Papunya Tula: Genesis and Genius, at the Art Gallery of New South Wales.

Working in synthetic polymer on linen or canvas, Makinti's paintings take as their subjects a rockhole site, an indigenous story about two sisters, known as Kungka Kutjarra. She was a member of the Papunya Tula Artists Cooperative, but her work has been described as more spontaneous than that of her fellow Papunya Tula artists. Makinti Napanangka's year of birth is uncertain, but several sources indicate she was born around 1930, although other sources indicate she may have been born as early as 1922 or as late as 1932 at a location described by some sources as Lupul rockhole but by one major reference work as Mangarri. All sources agree that she comes from the area of Karrkurritinytja or Lake MacDonald, which straddles the border between Western Australia and the Northern Territory, 50 kilometres south-west of Kintore, about 500 kilometres west of Alice Springs. Makinti was a member of the Pintupi group of indigenous people, who are associated with the communities of Papunya and Kiwirrkura.

"Napanangka" is a skin name, one of eight used to denote the subgroups in the Pintupi kinship system, not a surname in the sense used by Europeans. Thus her personal name was "Makinti"; the uncertainty around Makinti's date and place of birth arises from the fact that Indigenous Australians estimate dates of birth by comparison with other events for people born before contact with European Australians. They may cite the place of birth as being where the mother first felt the foetus move, rather than where the birth took place. Makinti's first contact with white people was seeing them riding camels, when she was living at Lupul, she was one of a large group of people who walked into Haasts Bluff in the early 1940s, together with her husband Nyukuti Tjupurrula, their son Ginger Tjakamarra, born around 1940. At Haasts Bluff they had a second child, Narrabri Narrapayi, in 1949; the population moved to Papunya in the late 1950s, where Makinti had another child, Jacqueline Daaru, in 1958. She had Winnie Bernadette, in 1961 in Alice Springs.

The family moved to Kintore when it was established in the early 1980s, by 1996 Kumentje was painting there for the Papunya Tula Artists Cooperative. Her children Ginger and Jacqueline became artists, all of them painting for Papunya Tula Artists. Physically tiny yet robust and strong, Kumentje was described as "a charmer and an irascible character", with an infectious smile, she died in Alice Springs in January 2011. Artists of the Papunya Tula movement were painting at Haasts Bluff in the late 1970s, but the deaths of some of the main painters in the early 1980s led to a period of decline. In 1992, the Ikuntji Women's Centre was opened at Haasts Bluff and a new painting movement developed, supported by founding art coordinator Marina Strocchi, who assisted in artists' development at both Haasts Bluff and Kintore, it was through this initiative that Kumentje began painting in 1994 for the Minyma Tjukurrpa and by 1997 her work was being acquired by major collecting institutions. She was one of the "Kintore ladies" who joined earlier generations of the famous Papunya Tula artists, was referred to as "number one" by her fellow artists, of whom she was considered a leader.

She painted with the Papunya Tula Artists Cooperative, in which she was a shareholder, from 1996. The only break in her career was in 1999, when she underwent a cataract operation, an event that journalist Nicolas Rothwell suggested was associated with a distinct shift in her work, including the increasing use of thick lines. Johnson said the operation resulted in "a collection of light-flooded canvases". Makinti's works were selected to hang in five consecutive National Aboriginal and Torres Strait Islander Art Award exhibitions, beginning in 1997. In 2000, she held her first solo exhibition, was one of the artists whose works were included in the major exhibition Papunya Tula: Genesis and Genius at the Art Gallery of New South Wales; the following year, she was a finalist at the NATSIAA. 2003 saw her named by Australian Art Collector magazine as one of the country's 50 most collectible artists, an assessment repeated by that magazine in 2004, 2005, 2006. In 2003, she was among the finalists for the Clemenger Contemporary Art Award.

By 2006, her works were commanding "the upper end of the price spectrum", though the resale values of those of her works not sold through Papunya Tula artists were cons

Andrei Alba

Andrei Alba is a Brazilian professional footballer who plays as a defensive midfielder for Concórdia, on loan from Chapecoense. Born in Engenho Velho, Rio Grande do Alba was a Chapecoense youth graduate. On 25 January 2016, shortly after being promoted to the first team, he signed a new contract with the club running until 2018. Alba made his senior debut on 14 February 2016, coming on as a second-half substitute for Josimar in a 2–0 Campeonato Catarinense away win against Brusque, his Série A debut came on 4 June, as he replaced injured Moisés Ribeiro in a 0–0 home draw against Fluminense. On 21 July 2016, Alba was loaned to Concórdia until the end of the year. Returning to Chape in January 2017 after contributing with 16 matches, he suffered a serious knee injury, being sidelined for several months; as of 8 April 2017 AV Assessoria profile Andrei Alba at Soccerway