SUMMARY / RELATED TOPICS

Stellarator

A stellarator is a plasma device that relies on external magnets to confine a plasma. In the future, scientists researching magnetic confinement fusion aim to use stellarator devices as a vessel for nuclear fusion reactions; the name refers to the possibility of harnessing the power source including the sun. It is one of the earliest fusion power devices, along with the magnetic mirror; the stellarator was invented by Lyman Spitzer of Princeton University in 1951, much of its early development was carried out by his team at what became the Princeton Plasma Physics Laboratory. Lyman's Model A demonstrated that stellarators could confine plasmas. Larger models followed, but these demonstrated poor performance, suffering from a problem known as pump-out that caused them to lose plasma at rates far worse than theoretical predictions. By the early 1960s, any hope of producing a commercial machine faded, attention turned to studying the fundamental theory of high-energy plasmas. By the mid-1960s, Spitzer was convinced that the stellarator was matching the Bohm diffusion rate, which suggested it would never be a practical fusion device.

The release of information on the USSR's tokamak design in 1968 indicated a leap in performance. This led to the Model C stellarator being converted to the Symmetrical Tokamak as a way to confirm or deny these results. ST confirmed them, large-scale work on the stellarator concept ended as the tokamak got most of the attention; the tokamak proved to have similar problems to the stellarators, but for different reasons. Since the 1990s, this has led to renewed interest in the stellarator design. New methods of construction have increased the quality and power of the magnetic fields, improving performance. A number of new devices have been built to test these concepts. Major examples include Wendelstein 7-X in Germany, the Helically Symmetric Experiment in the US, the Large Helical Device in Japan. In 1934, Mark Oliphant, Paul Harteck and Ernest Rutherford were the first to achieve fusion on Earth, using a particle accelerator to shoot deuterium nuclei into a metal foil containing deuterium, lithium or other elements.

These experiments allowed them to measure the nuclear cross section of various reactions of fusion between nuclei, determined that the tritium-deuterium reaction occurred at a lower energy than any other fuel, peaking at about 100,000 electronvolts.100 keV corresponds to a temperature of about a billion kelvins. Due to the Maxwell–Boltzmann statistics, a bulk gas at a much lower temperature will still contain some particles at these much higher energies; because the fusion reactions release so much energy a small number of these reactions can release enough energy to keep the gas at the required temperature. In 1944, Enrico Fermi demonstrated that this would occur at a bulk temperature of about 50 million Celsius, still hot but within the range of existing experimental systems; the key problem was confining such a plasma. But because plasmas are electrically conductive, they are subject to electric and magnetic fields which provide a number of solutions. In a magnetic field, the electrons and nuclei of the plasma circle the magnetic lines of force.

One way to provide some confinement would be to place a tube of fuel inside the open core of a solenoid. A solenoid creates magnetic lines running down its center, fuel would be held away from the walls by orbiting these lines of force, but such an arrangement does not confine the plasma along the length of the tube. The obvious solution is to bend the tube around into a torus shape, so that any one line forms a circle, the particles can circle forever. However, this solution does not work. For purely geometric reasons, the magnets ringing the torus are closer together on the inside curve, inside the "donut hole". Fermi noted this would cause the electrons to drift away from the nuclei causing them to separate and cause large voltages to develop; the resulting electric field would cause the plasma ring inside the torus to expand until it hit the walls of the reactor. In the post-war era, a number of researchers began considering different ways to confine a plasma. George Paget Thomson of Imperial College London proposed a system now known as z-pinch, which runs a current through the plasma.

Due to the Lorentz force, this current creates a magnetic field that pulls the plasma in on itself, keeping it away from the walls of the reactor. This eliminates the need for magnets on the outside. Various teams in the UK had built a number of small experimental devices using this technique by the late 1940s. Another person working on controlled fusion reactors was Ronald Richter, a former German scientist who moved to Argentina after the war, his thermotron used a system of electrical arcs and mechanical compression for heating and confinement. He convinced Juan Perón to fund development of an experimental reactor on an isolated island near the Chilean border. Known as the Huemul Project, this was completed in 1951. Richter soon convinced himself fusion had been achieved in spite of other people working on the project disagreeing; the "success" was announced by Perón on 24 March 1951, becoming the topic of newspaper stories around the world. While preparing for a ski trip to Aspen, Lyman Spitzer received a telephone call from his father, who mentioned an article on Huemul in The New York Times.

Looking over the description in the article, Spitzer concluded it could not work. But the idea stuck with him, he began considering systems that wou

Katedralskolan, Skara

Katedralskolan in Skara is one of Sweden's oldest Upper Secondary Schools. It was founded in 1641 at the initiative of the Diocese of Skara, its bishop Jonas Magni Wexionensis, was approved by Queen Christina on August 31 of the same year. For hundreds of years before that it had been a priest training school, founded in the 13th century and the students were called Skaradjäknar. In June 1864 first student group took the final exam in Skara. Earlier the exam had been taken at a university. In 1878 came the name Higher general secondary school, which remained until 1965; the school opened for girls in 1927. The school had long been located in a building east of Skara Cathedral Choir by the then-high wall surrounding the cathedral churchyard; the building was demolished in the late 19th century, when the neo-Gothic building with a typical lecture hall was built south of the cathedral. In 1972, the current main building, more on the edge of Skara, was finished, the school moved; the former high school building is now an elementary school for grades 7-9 called Djäkneskolan whose students are called Djäknar The school has had, during its time, many students who have become famous, poet Johan Henrik Kellgren, chemist Torbern Bergman and the Swedish veterinary medicine's father Peter Hernqvist to name a few.

The school's motto is "Där tradition och framtid möts". The school offers most of the programs available at this level in Sweden: Barn- och fritidsprogrammet, with the specialization socialt arbete. Bygg- och anläggningsprogrammet, with the specializations byggnadsplåt and husbyggnad. Ekonomiprogrammet, with the specialization ekonomi. Beginning autumn of 2011. El- och energiprogrammet, with the specialization elteknik. Estetiska programmet, with the specializations dans, Musik - MoP Music and Productions and teater. Fordons- och transportprogrammet, with specializations Lastbil och mobila maskiner and transport. Gymnasiesärskolan. Handel och service, beginning autumn 2011. Mediaprogrammet until autumn 2011. Naturvetenskapsprogrammet, with the specialization naturvetenskap. Omvårdnad Lärling. Restaurang- och livsmedelsprogrammet, with the specializations bageri och konditori. Samhällsvetenskapsprogrammet, with the specializations samhällsvetenskap (further divided into samhällsvetenskap and journalistik, språk and ekonomi for students that began their studies before 1 July 2011, for students samhällsvetenskap and medier, information och kommunikation Teknikprogrammet, with the specialization design och produktutveckling Vård- och omsorgsprogrammet.

Cathedral School offers the international education International Baccalaureate and the specially designed program and Production. This musical education has its offices in a building prepared for the recording of Fame Factory. MoP has generated pupils who have made a name in the music industry, for example, there are members of Zeke's students in the program; the teachers at MoP include, for example, Lars Diedricson and Kristian Wejshag, who among other things, have made a contribution for Melodifestivalen 2010. When Gunnar Wennerberg was a student at Cathedral School, he co-founded the chorus, double quartet; when Wennerberg became philosophy lecturer at the school in 1886, he co-founded the choir music's Friends. Both of these choirs are still active at Cathedral School, have become a traditional feature of Skara's culture. MV and DQ provides, inter alia, continuous concerts in the Botanical Garden in Skara in May, they provide an Advent concert in the cathedral and sing for the bishop in a traditional courtship.

In 1977 a choir of female students was formed, called Octo Puellae which now is an equal key element of the school's music scene. The choirs are important for Cathedral School's graduation ceremony The Skara Deacon Association is an association for those who have been pupils at the school; the association, founded in 1916, has 1650 members. SDA has departments with various activities at four locations: Stockholm, Malmö and Skara; the purpose of SDA is to preserve and enhance the sense of community with those who, through the years, have gone through secondary school education in Skara. The term "Deacon" is now used for students at traditional high schools like the Cathedral School in Skara and Uppsala. Famous students from Cathedral School: Torbern Bergman Johannes Edfelt Peter Hernqvist Johan Henrik Kellgren Ernst Killander Linda Sundblad Gunnar Wennerberg Cathedral School's homepage skaradjaknarna.com

Cameron Township, Murray County, Minnesota

Cameron Township is a township in Murray County, United States. The population was 151 at the 2000 census. Cameron Township was organized in 1878, named for Charles Cameron Cole, a pioneer settler. According to the United States Census Bureau, the township has a total area of 36.0 square miles, of which 35.9 square miles of it is land and 0.2 square miles of it is water. As of the census of 2000, there were 151 people, 53 households, 41 families residing in the township; the population density was 4.2 people per square mile. There were 59 housing units at an average density of 1.6/sq mi. The racial makeup of the township was 0.66 % Asian. There were 53 households out of which 43.4% had children under the age of 18 living with them, 75.5% were married couples living together, 22.6% were non-families. 22.6% of all households were made up of individuals and 5.7% had someone living alone, 65 years of age or older. The average household size was 2.85 and the average family size was 3.37. In the township the population was spread out with 31.1% under the age of 18, 11.9% from 18 to 24, 23.8% from 25 to 44, 25.2% from 45 to 64, 7.9% who were 65 years of age or older.

The median age was 35 years. For every 100 females, there were 98.7 males. For every 100 females age 18 and over, there were 112.2 males. The median income for a household in the township was $25,833, the median income for a family was $30,625. Males had a median income of $21,406 versus $27,500 for females; the per capita income for the township was $12,991. There were 14.3% of families and 17.0% of the population living below the poverty line, including 16.3% of under eighteens and none of those over 64. Cameron Township is located in Minnesota's 1st congressional district, represented by Mankato educator Tim Walz, a Democrat. At the state level, Cameron Township is located in Senate District 22, represented by Republican Doug Magnus, in House District 22A, represented by Republican Joe Schomacker