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Transwiki:Relative Density
Template:Twwp-2 Relative density is a dimensionless ratio of the densities of two materials. The term specific gravity is similar, except that the reference material is water. A relative density can help quantify the buoyancy between two materials, or determine the density of one "unknown" material using the "known" density of another material. Mathematically, relative density is expressed as: where [math]\displaystyle{ G }[/math] is the relative density, and [math]\displaystyle{ \rho }[/math] is the densities of the two materials in the same units (e.g., kg/m³, g/cm³). Relative density is dimensionless, since it is a ratio between two quantities of same unit. If the ratio is greater than 1, the object will be heavier than the same volume of the reference. If it is less than 1, it will be lighter than the reference. It is important to specify the reference material when reporting a relative density, but when the reference material is not specified it is usually understood to be water at 3.98 ° C.
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Topic Review
EPR (Nuclear Reactor)
The EPR is a third generation pressurised water reactor (PWR) design. It has been designed and developed mainly by Framatome (part of Areva between 2001 and 2017) and Électricité de France (EDF) in France, and Siemens in Germany. In Europe this reactor design was called European Pressurised Reactor, and the internationalised name was Evolutionary Power Reactor, but it is now simply named EPR. The first two EPR units, at Olkiluoto in Finland and Flamanville in France, are both facing costly construction delays (to at least 2019). Construction commenced on two Chinese units at Taishan in 2009 and 2010. Taishan 1 achieved criticality on 6 June 2018. Taishan 2 is expected to begin operation in 2019. Two units at Hinkley Point in the United Kingdom received final approval in September 2016 and are expected to be completed by 2025. EDF has acknowledged severe difficulties in building the EPR design. In September 2015 EDF stated that the design of a "New Model" EPR was being worked on, which will be easier and cheaper to build.
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Biography
Vera Kistiakowsky
Vera Kistiakowsky (born 1928) is an United States research physicist, teacher, and arms control activist.[1] She is professor emerita at Massachusetts Institute of Technology in the physics department and Laboratory for Nuclear Science, and is an activist for women's participation in the sciences. Dr. Kistiakowsky is an expert in experimental particle physics and observational astrophysics.[2] S
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Topic Review
BlackDog
The BlackDog is a pocket-sized, self-contained computer with a built-in biometric fingerprint reader which was developed in 2005 by Realm Systems, which is plugged into and powered by the USB port of a host computer using its peripheral devices for input and output. It is a mobile personal server which allows a user to use Linux, ones applications and data on any computer with a USB port. The host machine's monitor, keyboard, mouse, and Internet connection are used by the BlackDog for the duration of the session. As the system is self-contained and isolated from the host, requiring no additional installation, it is possible to make use of untrusted computers, yet using a secure system. Various hardware iterations exist, and the original developer Realm Systems closed down in 2007, being picked up by the successor Inaura, Inc.
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Topic Review
New Pedestrianism
New Pedestrianism (NP) is a more pedestrian and ecology-oriented variation of New Urbanism in urban planning theory, founded in 1999 by Michael E. Arth, an American artist, urban/home/landscape designer, futurist, and author. NP addresses the problems associated with New Urbanism and is an attempt to solve various social, health, energy, economic, aesthetic, and environmental problems, with special focus on reducing the role of the automobile.A neighborhood or new town utilizing NP is called a Pedestrian Village. Pedestrian Villages can range from being nearly car-free to having automobile access behind nearly every house and business, but pedestrian lanes are always in front. To a large extent New Urbanism is a revival of traditional street patterns and urban design. New Pedestrianism also respects traditional town design, but seeks to further reduce the negative impact of the automobile, the use of which has increased dramatically since WWII. By eliminating the front street and replacing it with a tree-lined pedestrian lane, emphasis is placed on low-impact alternative travel such as walking and cycling. Pedestrian lanes are usually 12 to 15 feet (5 m) wide, with one smooth side for rolling conveyances such as bicycles, Segways, and skates and the other, narrower, textured side for pedestrians and wheelchairs. Eliminating the automobile street from the front allows for intimate scale plazas, fountains, pocket parks, as well as an unspoiled connection to natural features such as lakes, streams, and forests that may border or be included in a Pedestrian Village. A vast public realm is created that is free from the sight, smell, and sound of automobiles, yet automobiles are still served on a separate network. New Pedestrianism has been proposed for Kisima Kaya, a new town in Kenya, for Tiger Bay Village, FL as a solution to the homeless problem, and for new towns and neighborhoods that can be built anywhere whether as rehabilitation of existing neighborhoods, infill, edge-of-town neighborhoods, or new towns.
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Topic Review
Fusil Automatique Modèle 1917
The Fusil Automatique Modèle 1917 (English: Model 1917 Automatic Rifle) (also called the RSC M1917 ) was a gas-operated, semi-automatic rifle that the French Army placed in service during the latter part (1917) of World War I. It was chambered in then-standard 8mm Lebel, the rimmed cartridge used in other French Army infantry weapons of the time. Altogether, the French National Armories (primarily MAS (Manufacture d'Armes de St Etienne) and MAT (Manufacture d'Armes de Tulle) had manufactured 86,000 RSC M1917 rifles when their production run ended in late November 1918. However very few have survived in fully functional, semi-automatic condition and those have become highly sought-after collectibles.
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Topic Review
Pilar (Boat)
Ernest Hemingway owned a 38-foot (12 m) fishing boat named Pilar. It was acquired in April 1934 from Wheeler Shipbuilding in Brooklyn, New York, for $7,495. "Pilar" was a nickname for Hemingway's second wife, Pauline, and also the name of the woman leader of the partisan band in his 1940 novel of the Spanish Civil War, For Whom the Bell Tolls. Hemingway regularly fished off the boat in the waters of Key West, Florida, Marquesas Keys, and the Gulf Stream off the Cuban coast. He made three trips with the boat to the Bimini islands wherein his fishing, drinking, and fighting exploits drew much attention and remain part of the history of the islands. In addition to fishing trips on Pilar, Hemingway contributed to scientific research which included collaboration with the Smithsonian Institution. Several of Hemingway's books were influenced by time spent on the boat, most notably, The Old Man and the Sea (1953) and Islands in the Stream (1970). The yacht also inspired the name of Playa Pilar (Pilar Beach) on Cayo Guillermo. A smaller replica of the boat is depicted in the opening and other scenes in the 2012 film Hemingway & Gellhorn.
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Topic Review
Reservoir Modeling
In the oil and gas industry, reservoir modeling involves the construction of a computer model of a petroleum reservoir, for the purposes of improving estimation of reserves and making decisions regarding the development of the field, predicting future production, placing additional wells, and evaluating alternative reservoir management scenarios. A reservoir model represents the physical space of the reservoir by an array of discrete cells, delineated by a grid which may be regular or irregular. The array of cells is usually three-dimensional, although 1D and 2D models are sometimes used. Values for attributes such as porosity, permeability and water saturation are associated with each cell. The value of each attribute is implicitly deemed to apply uniformly throughout the volume of the reservoir represented by the cell.
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Topic Review
Chubut Province
Chubut (Spanish: Provincia del Chubut, IPA: [tʃuˈβut]; Welsh: Talaith Chubut) is a province in southern Argentina , situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes range to the west, and the Atlantic ocean to the east. The province's name derives from the Tehuelche word chupat, meaning "transparent," their description of the Chubut River. The largest city is Comodoro Rivadavia in the south of the province; it has 180,000 inhabitants. The administrative capital is Rawson (40,000). Other important cities are Puerto Madryn, Trelew, Esquel and Sarmiento. Gaiman is a cultural and demographic centre of the region known as "Y Wladfa" in which Welsh-Argentines are concentrated. Of the 25,000 Welsh speakers in Argentina, 5,000 live in the Chubut region, particularly in the early Welsh settlements of Gaiman, Trelew and Trevelin.
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Topic Review
Visegrád Group
The Visegrád Group, Visegrád Four, or V4, is a cultural and political alliance of four Central European countries – the Czech Republic, Hungary, Poland and Slovakia, that are members of the European Union (EU) and NATO – for the purposes of advancing military, cultural, economic and energy cooperation with one another along with furthering their integration in the EU. The Group traces its origins to the summit meetings of leaders from Czechoslovakia, Hungary, and Poland held in the Hungarian castle-town of Visegrád on 15 February 1991. Visegrád was chosen as the location for the 1991 meeting as an intentional allusion to the medieval Congress of Visegrád in 1335 between John I of Bohemia, Charles I of Hungary and Casimir III of Poland. After the dissolution of Czechoslovakia in 1993, the Czech Republic and Slovakia became independent members of the group, thus increasing the number of members from three to four. All four members of the Visegrád Group joined the European Union on 1 May 2004.
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