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Automatic Door
An automatic door, also known as an auto door, is a door that opens automatically, usually on sensing the approach of a person.
In the 1st century AD, mathematician Heron of Alexandria in Roman Egypt invented the first known automatic door. He described two different automatic door applications. The first application used heat from a fire lit by the city's temple priest. After a few hours atmospheric pressure built up in a brass vessel causing it to pump water into adjacent containers. These containers acted as weights that – through a series of ropes and pulleys – would open the temple's doors at about the time people were to arrive for prayer. Heron used a similar application to open the gates to the city.[1]
In 1931, engineers Horace H. Raymond and Sheldon S. Roby of the tool and hardware manufacturer Stanley Works designed the first model of an optical device triggering the opening of an automatic door. The invention was patented and installed in Wilcox's Pier Restaurant in West Haven, Connecticut for the benefit of waiters carrying plates of food and drink. The entire system plus installation was sold for $100.[2][3]
In 1954, Dee Horton and Lew Hewitt invented the first sliding automatic door. The automatic door used a mat actuator. In 1960, they co-founded Horton Automatics Inc and placed the first commercial automatic sliding door on the market.[4]
Cambridge (/ˈkeɪmbrɪdʒ/[2] KAYM-brij) is a university city and the county town of Cambridgeshire, England, on the River Cam approximately 55 miles (89 km) north of London. At the United Kingdom Census 2011, the population of the Cambridge built-up area (which is larger than the remit of Cambridge City Council) was 158,434 including 29,327 students.[3] Cambridge became an important trading centre during the Roman and Viking ages, and there is archaeological evidence of settlement in the area as early as the Bronze Age. The first town charters were granted in the 12th century, although modern city status was not officially conferred until 1951.
The University of Cambridge was founded in 1209.[4] The buildings of the university include King's College Chapel, Cavendish Laboratory, and the Cambridge University Library, one of the largest legal deposit libraries in the world. The city's skyline is dominated by several college buildings, along with the spire of the Our Lady and the English Martyrs Church, and the chimney of Addenbrooke's Hospital. Anglia Ruskin University, which evolved from the Cambridge School of Art and the Cambridgeshire College of Arts and Technology, also has its main campus in the city.
Cambridge is at the heart of the high-technology Silicon Fen with industries such as software and bioscience and many start-up companies born out of the university. Over 40 per cent of the workforce have a higher education qualification, more than twice the national average. The Cambridge Biomedical Campus, one of the largest biomedical research clusters in the world, is soon to house premises of AstraZeneca, a hotel, and the relocated Royal Papworth Hospital.[5]
The first game of association football took place at Parker's Piece. The Strawberry Fair music and arts festival and Midsummer Fair are held on Midsummer Common, and the annual Cambridge Beer Festival takes place on Jesus Green. The city is adjacent to the M11 and A14 roads. Cambridge station is less than an hour from London King's Cross railway station.
