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"Yrast ( , ) is a technical term in nuclear physics that refers to a state of a nucleus with a minimum of energy (when it is least excited) for a given angular momentum. Yr is a Swedish adjective sharing the same root as the English whirl. Yrast is the superlative of yr and can be translated whirlingest, although it literally means "dizziest" or "most bewildered". The yrast levels are vital to understanding reactions, such as off-center heavy ion collisions, that result in high-spin states. Yrare is the comparative of yr and is used to refer to the second-least energetic state of a given angular momentum. Background An unstable nucleus may decay in several different ways: it can eject a neutron, proton, alpha particle, or other fragment; it can emit a gamma ray; it can undergo beta decay. Because of the relative strengths of the fundamental interactions associated with those processes (the strong interaction, electromagnetism, and the weak interaction respectively), they usually occur with frequencies in that order. Theoretically, a nucleus has a very small probability of emitting a gamma ray even if it could eject a neutron, and beta decay rarely occurs unless both of the other two pathways are highly unlikely. In some instances, however, predictions based on this model underestimate the total amount of energy released in the form of gamma rays; that is, nuclei appear to have more than enough energy to eject neutrons, but decay by gamma emission instead. This discrepancy is found by the energy of a nuclear angular momentum, and documentation and calculation of yrast levels for a given system may be used for analyzing such a situation. The energy stored in the angular momentum of an atomic nucleus can also be responsible for the emission of larger-than-expected particles, such as alpha particles over single nucleons, because they can carry away angular momentum more effectively. This is not the only reason alpha particles are preferentially emitted, though; another reason is simply that alpha particles (He-4 nuclei) are energetically very stable in and of themselves. Yrast isomers Sometimes there is a large gap between two yrast states. For example, the nucleus 95Pd has a 21/2 state that lies below the lowest 19/2, 17/2, and 15/2 states. This state does not have enough energy to undergo strong particle decay, and because of the large spin difference, gamma decay from the 21/2 state to the 13/2 state below is very unlikely. The more likely decay option is beta decay, which forms an isomer with an unusually long half- life of 14 seconds. An exceptional example is the J=9 state of tantalum-180, which is a very low-lying yrast state only 77 keV above the ground state. The ground state has J=1, which is too large a gap for gamma decay to occur. Alpha and beta decay are also suppressed, so strongly that the resulting isomer, tantalum-180m, is effectively stable for all practical purposes, and has never been observed to decay. Tantalum-180m is the only currently known yrast isomer to be observationally stable. Some superheavy isotopes (such as copernicium-285) have longer-lived isomers with half-lives on the order of minutes. These may be yrasts, but the exact angular momentum and energy is often hard to determine for these nuclides. References Category:Swedish words and phrases Category:Nuclear physics "
"Sir Arthur Frederic Brownlow fforde GBE (23 August 1900 – 26 June 1985) was an English solicitor, civil servant, headmaster, writer and businessman. Arthur fforde was educated at Rugby School (SH 1914–1919, Head of School) and Trinity College, Oxford. As a solicitor, he became a partner in the law firm Linklaters & Paines (now known as Linklaters) and also had helped establish the Unit trust. In 1948 he returned to Rugby as head master, remaining until 1957,Rugby School Who's Who, 1975 when he became Chairman of the BBC. In 1964 he retired after a spell of ill-health and was appointed a Knight Grand Cross of the Order of the British Empire the same year. Occasional verses by Arthur fforde were published later in his life, until his death in 1985. Notes References Category:1900 births Category:1985 deaths Category:BBC Governors Category:Chairmen of the BBC Category:Head Masters of Rugby School Category:People educated at Rugby School Category:Alumni of Trinity College, Oxford Category:20th-century British poets Category:Knights Bachelor Category:Knights Grand Cross of the Order of the British Empire Category:English solicitors "
"Swansea Civic Centre () – formerly known as County Hall – is the principal administrative centre of the City and County of Swansea Council. Standing some 800 m southwest of Swansea centre on a seafront site overlooking Swansea Bay, the complex houses – in addition to the council chamber and offices – a public cafe, the city's central library, an exhibition space, the West Glamorgan Archive Service, and a council contact centre. History Following the implementation of the Local Government Act 1972, which broke up Glamorgan County Council and established West Glamorgan County Council, the new county council initially met at Swansea Guildhall.Whitaker's Almanack 1979, p. 677 A purpose-built facility was commissioned as the headquarters of the new county council and was designed by C. W. Quick of the West Glamorgan County Architects Department. It was opened as County Hall in July 1982. Queen Elizabeth II visited the new building in April 1989. After local government re-organisation in 1996, which abolished West Glamorgan County Council, ownership of the building was transferred to the new City and County of Swansea. The building was renamed the Civic Centre on 19 March 2008, and Swansea Central Library was moved in as part of a redevelopment scheme. The library issued nearly 566,000 loans in 2008/09, making it the busiest in Wales and the tenth busiest in the UK. In June 2017 Swansea Council announced plans to redevelop the area, the second phase of which would involve demolition of Swansea Civic Centre and the creation of city beach which would also include an aquarium and digital science centre. Public Transport See also *Guildhall, Swansea References External links *21st century civic centre project starts Category:Buildings and structures in Swansea Category:County halls in Wales Category:Swansea Bay Category:Buildings and structures completed in 1982 Category:Event venues established in 1982 Category:1982 establishments in Wales "