SUMMARY / RELATED TOPICS

Electronics

Electronics comprises the physics, engineering and applications that deal with the emission and control of electrons in vacuum and matter. This distinguishes it from classical electrical engineering as it uses active devices to control electron flow by amplification and rectification rather than just using passive effects such as resistance and inductance; the identification of the electron in 1897, along with the subsequent invention of the vacuum tube which could amplify and rectify small electrical signals, inaugurated the field of electronics and the electron age. This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device; until 1950, this field was called "radio technology" because its principal application was the design and theory of radio transmitters and vacuum tubes. The term "solid-state electronics" emerged after the first working transistor was invented by William Shockley, Walter Houser Brattain and John Bardeen at Bell Labs in 1947.

The MOSFET was invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959. The MOSFET was the first compact transistor that could be miniaturised and mass-produced for a wide range of uses, revolutionizing the electronics industry, playing a central role in the microelectronics revolution and Digital Revolution; the MOSFET has since become the basic element in most modern electronic equipment, is the most used electronic device in the world. Electronics is used in information processing, telecommunication, signal processing; the ability of electronic devices to act as switches makes digital information-processing possible. Interconnection technologies such as circuit boards, electronics packaging technology, other varied forms of communication infrastructure complete circuit functionality and transform the mixed electronic components into a regular working system, called an electronic system. An electronic system may be a component of a standalone device; as of 2019 most electronic devices use semiconductor components to perform electron control.

Electronic devices contain circuitry consisting of active semiconductors supplemented with passive elements. Electronics deals with electrical circuits that involve active electrical components such as vacuum tubes, diodes, integrated circuits and sensors, associated passive electrical components, interconnection technologies; the nonlinear behaviour of active components and their ability to control electron flows makes amplification of weak signals possible. The study of semiconductor devices and related technology is considered a branch of solid-state physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering; this article focuses on engineering aspects of electronics. Electronics has branches as follows: Digital electronics Analogue electronics Microelectronics Circuit design Integrated circuits Power electronics Optoelectronics Semiconductor devices Embedded systems Audio electronics Telecommunications An electronic component is any physical entity in an electronic system used to affect the electrons or their associated fields in a manner consistent with the intended function of the electronic system.

Components are intended to be connected together by being soldered to a printed circuit board, to create an electronic circuit with a particular function. Components may be packaged singly, or in more complex groups as integrated circuits; some common electronic components are capacitors, resistors, transistors, etc. Components are categorized as active or passive. Vacuum tubes were among the earliest electronic components, they were solely responsible for the electronics revolution of the first half of the twentieth century. They allowed for vastly more complicated systems and gave us radio, phonographs, long-distance telephony and much more, they played a leading role in the field of microwave and high power transmission as well as television receivers until the middle of the 1980s. Since that time, solid-state devices have all but taken over. Vacuum tubes are still used in some specialist applications such as high power RF amplifiers, cathode ray tubes, specialist audio equipment, guitar amplifiers and some microwave devices.

The first working point-contact transistor was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947. In April 1955, the IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the first all-transistorized calculator to be manufactured for the commercial market; the 608 contained more than 3,000 germanium transistors. Thomas J. Watson Jr. ordered all future IBM products to use transistors in their design. From that time on transistors were exclusively used for computer logic and peripherals. However, early junction transistors were bulky devices that were difficult to manufacture on a mass-production basis, which limited them to a number of specialised applications; the MOSFET was invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959. The MOSFET was the first compact transistor that could be miniaturised and mass-produced for a wide range of uses, its advantages include high scalability, low power consump

Insect wing

Insect wings are adult outgrowths of the insect exoskeleton that enable insects to fly. They are found on the second and third thoracic segments, the two pairs are referred to as the forewings and hindwings though a few insects lack hindwings rudiments; the wings are strengthened by a number of longitudinal veins, which have cross-connections that form closed "cells" in the membrane. The patterns resulting from the fusion and cross-connection of the wing veins are diagnostic for different evolutionary lineages and can be used for identification to the family or genus level in many orders of insects. Physically, some insects move others indirectly. In insects with direct flight, the wing muscles directly attach to the wing base, so that a small downward movement of the wing base lifts the wing itself upward; those insects with indirect flight have muscles that attach to and deform the thorax, causing the wings to move as well. The wings are present in only one sex in some groups such as velvet ants and Strepsiptera, or are selectively lost in "workers" of social insects such as ants and termites.

The female is winged but the male not, as in fig wasps. In some cases, wings are produced only at particular times in the life cycle, such as in the dispersal phase of aphids. Wing structure and colouration vary with morphs, such as in the aphids, migratory phases of locusts and polymorphic butterflies. At rest, the wings folded a number of times along specific patterns. How and why insect wings evolved is not well understood and there has been a long standing debate about their origins. During the 19th century, the question of insect wing evolution rested on two main positions. One position postulated insect wings evolved from pre-existing structures, while the second proposed insect wings were novel formations; the “novel” hypothesis suggested that insect wings did not form from pre-existing ancestral appendages but rather as outgrowths from the insect body wall. Long since, research on insect wing origins has built on the “pre-existing structures” position, proposed in the 19th century. Recent literature has pointed to several ancestral structures as being important to the origin of insect wings.

Among these include: gills, respiratory appendages of legs, lateral and posterolateral projections of the thorax to name a few. According to more current literature, gill-like structures and the paranotal lobe still appear to be among the most important ancestral structures to insect wing origins. Today, there are three main theories on the origins of insect flight; these theories are referred to as the paranotal lobe theory, the gill theory and the dual theory of insect wing evolution. These theories postulate that wings either developed from paranotal lobes, extensions of the thoracic terga; each of the wings consists of a thin membrane supported by a system of veins. The membrane is formed by two layers of integument apposed, while the veins are formed where the two layers remain separate. Within each of the major veins there is a nerve and a trachea, since the cavities of the veins are connected with the hemocoel, hemolymph can flow into the wings; as the wing develops, the dorsal and ventral integumental layers become apposed over most of their area forming the wing membrane.

The remaining areas form the future veins, in which the nerves and tracheae may occur. The cuticle surrounding the veins becomes thickened and more sclerotized to provide strength and rigidity to the wing. Two types of hair may occur on the wings: microtrichia, which are small and irregularly scattered, macrotrichia, which are larger and may be restricted to veins; the scales of Lepidoptera and Trichoptera are modified macrotrichia. In some small insects, the venation may be reduced. In Chalcidoidea, for instance, only the subcosta and part of the radius are present. Conversely, an increase in venation may occur by the branching of existing veins to produce accessory veins or by the development of additional, intercalary veins between the original ones, as in the wings of Orthoptera. Large numbers of cross-veins are present in some insects, they may form a reticulum as in the wings of Odonata and at the base of the forewings of Tettigonioidea and Acridoidea; the archedictyon is the name given to a hypothetical scheme of wing venation proposed for the first winged insect.

It is based on a combination of fossil data. Since all winged insects are believed to have evolved from a common ancestor, the archedictyon represents the "template", modified by natural selection for 200 million years. According to current dogma, the archedictyon contained 6–8 longitudinal veins; these veins are named according to a system devised by John Comstock and George Needham—the Comstock–Needham system: Costa – the leading edge of the wingSubcosta – second longitudinal vein unbranchedRadius – third longitudinal vein, one to five branches reach the

Semple Stadium

The Semple Stadium is the home of hurling and Gaelic football for Tipperary GAA and for the province of Munster. Located in the Home of Hurling Thurles, County Tipperary, it is the second largest GAA stadium in Ireland (after Croke Park, with a capacity of 51,000. Over the decades since 1926, it has established itself as the leading venue for Munster hurling followers,and attributed as having the best playing surface in the country, hosting the Munster Hurling Final on many memorable occasions; the main or ` Old Stand' of the ground lies across from the'New Stand'. Behind the goals are two uncovered terraces known as the'Town End' and the'Killinan End' respectively; the stadium has a capacity of 51,000 of which 24,000 are seated. The sports hall accommodates a full-sized basketball court suitable for national standard competition; the hall is lined for badminton and indoor soccer. It is used in the evenings and weekends by the Tipperary hurling and football teams for training and on match days, the building is used to accommodate GAA and sponsor guests for corporate lunches and functions.

It has been used as a music venue. In July 2018 Tipperary County Board prepared to submit plans to Tipperary County Council to see the Kinnane stand redeveloped into a multi-purpose facility; the proposal would see the “Old Stand” as it is known to many, have a second level created over the concourse at the back of the stand. The half nearest the Killinan End terrace will be dedicated to players and will include a full-sized gym, physio room, stats/analysis room plus changing rooms and toilet facilities; the other half, towards the Sarsfields Centre side, would include a function room to accommodate up to 250 people, with adjoining bar and kitchen facility for catering. The development will include a new corridor leading to a new VIP enclosure area in the Kinnane stand; the estimated cost of the project is €5 million. The planning application for the development was lodged with Tipperary County Council in April 2019; the planning application includes reconfiguration of the seating area and modifications to the ground floor, including turnstiles, the construction of a new exit gate, three service cores providing access to upper floor levels, which will include wheelchair-accessible turnstiles.

Wilson Architecture in Cork was commissioned to help put together the planning application. The grounds on which Semple Stadium is built were known as Thurles Sportsfield; the site was offered for sale in 1910 at the wish of Canon M. K. Ryan and was purchased by local Gaelic games enthusiasts for £900. To meet the cost of the purchase, an issue of shares was subscribed by the townspeople; the grounds remained in the hands of the shareholders until 1956 when they were transferred to the Gaelic Athletic Association. In 1934 in anticipation of the All-Ireland Hurling Final being held in the grounds to mark the golden jubilee of the Association, extensive improvements were made to bring the field requirements up to the demands which a crowd of up to 60,000 would make; the embankments around the field were raised and extended and the stand accommodation was extended. However, the jubilee final was held in Croke Park and it was another 50 years before the Stadium would host the long-awaited All-Ireland final as a showpiece to mark the centenary.

In 1968 further developments took place when the Dr. Kinane Stand was opened. In 1971 the stadium was named after Tom Semple, famed captain of the Thurles "Blues", he won All-Ireland Senior Hurling Championship medals in 1900, 1906 and 1908. The Ardán Ó Riáin opposite the Kinane Stand and the terracing at the town end of the field were completed in 1981 at a cost of £500,000; this development and the terracing at the Killinan end of the field were part of a major improvement scheme for the celebration of the centenary All-Ireland Hurling Final between Cork and Offaly in 1984. In April 2006 Tipperary County Board announced an €18 million redevelopment plan for the Stadium; the three-year project aimed to boost capacity to over 55,000, as well as providing a wide range of modern facilities such as corporate space concessions and changing areas within both main stands. There were plans to upgrade the standing terraces and install a modern floodlighting facility. Phase one of the upgrade project, upgrading the Kinnane Stand side of the stadium, involved expenditure of €5.5 million.

On 14 February 2009 the new state of the art floodlights were switched on by GAA President Nickey Brennan before the National Hurling League game against Cork. In 2016, Hawk-Eye was installed in the stadium and used for the first time during the Munster Championship quarter-final between Tipperary and Cork. An architectural consultancy has been appointed to lead a design team, tasked with preparing a master plan for the redevelopment of Semple Stadium; the Féile Festival, ran from 1990 to 1994, was held at Semple Stadium. At the height of its success, an estimated 150,000 people attended the festival, known as "The Trip to Tipp". Irish and international artists participated, including The Prodigy, The Cranberries, Bryan Adams, Van Morrison, Rage Against the Machine, The Saw Doctors and Christy Moore; the Féile Classical Concerts took place at Semple Stadium in September 2018. Line up included Irish musical acts. Named as Tipp Classical, it will return in September 2019. Semple Stadium is a five-minute walk from Thurles railway station.

The station is on the Dublin to Cork main rail line with connections to Limerick and