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John Tasker Henderson
John Tasker Henderson (9 December 1905 – 2 January 1983) was a Canadian Physicist whose career was with the National Research Council (NRC). Educated at McGill and London, Henderson joined the NRC in 1933 where he worked on the effects of the ionosphere on radio signals and the Direction Finder invented by A.G.L. McNaughton and W.A. Steel. In 1939, he became involved with the secret radar development and is particularly recognized for his leadership role in this technology during World War II, laying the foundations for radar research and manufacture in Canada. Henderson returned to the NRC after RCAF and diplomatic service from 1942–47 and became head of its electricity section, which built several cesium atomic clocks. Early life Henderson was born in Montreal, Quebec. He received the B.S. and M.S. degrees in engineering physics from McGill University, and then went to England, where he studied under Professor Edward Victor Appleton. He received the PhD degree in physics f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montreal
Montreal ( ; officially Montréal, ) is the List of the largest municipalities in Canada by population, second-most populous city in Canada and List of towns in Quebec, most populous city in the Provinces and territories of Canada, Canadian province of Quebec. Founded in 1642 as ''Fort Ville-Marie, Ville-Marie'', or "City of Mary", it is named after Mount Royal, the triple-peaked hill around which the early city of Ville-Marie is built. The city is centred on the Island of Montreal, which obtained its name from the same origin as the city, and a few much smaller peripheral islands, the largest of which is Île Bizard. The city is east of the national capital Ottawa, and southwest of the provincial capital, Quebec City. As of 2021, the city had a population of 1,762,949, and a Census Metropolitan Area#Census metropolitan areas, metropolitan population of 4,291,732, making it the List of the largest municipalities in Canada by population, second-largest city, and List of cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Range And Direction Finding
The history of radar (where radar stands for radio detection and ranging) started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell's seminal work on electromagnetism. However, it was not until the early 20th century that systems able to use these principles were becoming widely available, and it was German inventor Christian Hülsmeyer who first used them to build a simple ship detection device intended to help avoid collisions in fog (Reichspatent Nr. 165546). True radar, such as the British Chain Home early warning system provided directional information to objects over short ranges, were developed over the next two decades. The development of systems able to produce short pulses of radio energy was the key advance that allowed modern radar systems to come into existence. By timing the pulses on an oscilloscope, the range could be determined and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium
Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that are liquid at or near room temperature. Caesium has physical and chemical properties similar to those of rubidium and potassium. It is pyrophoric and reacts with water even at . It is the least electronegative element, with a value of 0.79 on the Pauling scale. It has only one stable isotope, caesium-133. Caesium is mined mostly from pollucite. The element has 40 known isotopes, making it, along with barium and mercury, one of the elements with the most isotopes. Caesium-137, a fission product, is extracted from waste produced by nuclear reactors. The German chemist Robert Bunsen and physicist Gustav Kirchhoff discovered caesium in 1860 by the newly developed method of flame spectroscopy. The first small-scale applications for caesium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SHORAN
SHORAN is an acronym for SHOrt RAnge Navigation, a type of electronic navigation and bombing system using a precision radar beacon. It was developed during World War II and the first stations were set up in Europe as the war was ending, and was operational with Martin B26 Marauders based in Corsica, and later based in Dijon and in B26's given to the South African Airforce in Italy. The first 10/10 zero visibility bombing was over Germany in March 1945. It saw its first combat use in the B-25, B-26 and B-29 bomber aircraft during the Korean War. SHORAN used ground-based transponders to respond to interrogation signals sent from the bomber aircraft. By measuring the round-trip time to and from one of the transponders, the distance to that ground station could be accurately determined. The aircraft flew an arcing path that kept it at a predetermined distance from one of the stations. The distance to a second station was also being measured, and when it reached a predetermined distan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toronto, Ontario
Toronto ( ; or ) is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the anchor of the Golden Horseshoe, an urban agglomeration of 9,765,188 people (as of 2021) surrounding the western end of Lake Ontario, while the Greater Toronto Area proper had a 2021 population of 6,712,341. Toronto is an international centre of business, finance, arts, sports and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world. Indigenous peoples have travelled through and inhabited the Toronto area, located on a broad sloping plateau interspersed with rivers, deep ravines, and urban forest, for more than 10,000 years. After the broadly disputed Toronto Purchase, when the Mississauga surrendered the area to the British Crown, the British established the town of York in 1793 and later designate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Research Enterprises Limited
Research Enterprises Limited (REL for short) was a short-lived Toronto-based Crown Corporation that built electronics and optical instruments during World War II. They existed only six years from late 1940 until 1946, and were active only from late 1941, but during that period they became Leaside's largest employer, producing C$220 million worth of radar systems and optical instruments ($ million in ). After the war, the government rapidly closed the various wartime companies it had started. After REL was closed, their factories formed the basis of a Corning Glass plant, Philips Electronics, and a variety of other firms. Today only a few of the original buildings still stand, used primarily for light industrial and small commercial enterprises. History NRC optics shop In August 1939, General Andrew McNaughton, President of the National Research Council (NRC), asked the head of the NRC's Optics Section, Leslie E. Howlett, to prepare a report on how to set up an optics industr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavity Magnetron
The cavity magnetron is a high-power vacuum tube used in early radar systems and currently in microwave ovens and linear particle accelerators. It generates microwaves using the interaction of a stream of electrons with a magnetic field while moving past a series of cavity resonators, which are small, open cavities in a metal block. Electrons pass by the cavities and cause microwaves to oscillate within, similar to the functioning of a whistle producing a tone when excited by an air stream blown past its opening. The resonant frequency of the arrangement is determined by the cavities' physical dimensions. Unlike other vacuum tubes, such as a klystron or a traveling-wave tube (TWT), the magnetron cannot function as an amplifier for increasing the intensity of an applied microwave signal; the magnetron serves solely as an oscillator, generating a microwave signal from direct current electricity supplied to the vacuum tube. The use of magnetic fields as a means to control the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington, D
Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. * George Washington (1732–1799), the first president of the United States Washington may also refer to: Places England * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough ** Washington Old Hall, ancestral home of the family of George Washington * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catarman, Northern Samar *Washington, a barangay in Escalante, Negros Occidental *Washington, a barangay in San Jacinto, Masbate *Washington, a barangay in Surigao City United States * Washington, Wisconsin (other) * Fort Washington (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tizard Mission
The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during WWII to obtain the industrial resources to exploit the military potential of the research and development (R&D) work completed by the UK up to the beginning of WWII, but that Britain itself could not exploit due to the immediate requirements of war-related production. It received its popular name from the programme's instigator, Henry Tizard. Tizard was a British scientist and chairman of the Aeronautical Research Committee, which had propelled the development of radar. The mission travelled to the US in September 1940 during the Battle of Britain. They intended to convey a number of technical innovations to the US to secure assistance in maintaining the war effort. Objectives The objective of the mission was to cooperate in science and technology with the U.S., which was neutral and, in many quarters, unwilling to become involved in the war. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Tizard
Sir Henry Thomas Tizard (23 August 1885 – 9 October 1959) was an English chemist, inventor and Rector of Imperial College, who developed the modern "octane rating" used to classify petrol, helped develop radar in World War II, and led the first serious studies of UFOs. Life Tizard was born in Gillingham, Kent in 1885, the only son of Thomas Henry Tizard (1839–1924), naval officer and hydrographer, and his wife, Mary Elizabeth Churchward. His ambition to join the navy was thwarted by poor eyesight, and he instead studied at Westminster School and Magdalen College, Oxford, where he concentrated on mathematics and chemistry, doing work on indicators and the motions of ions in gases. Tizard graduated in 1908 and at his tutor's suggestion he spent time in Berlin, where he met and formed a close friendship with Frederick Alexander Lindemann, later an influential scientific advisor of Winston Churchill. In 1909, he became a researcher in the Davy–Faraday Laboratory of the Roy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halifax Harbour
Halifax Harbour is a large natural harbour on the Atlantic coast of Nova Scotia, Canada, located in the Halifax Regional Municipality. Halifax largely owes its existence to the harbour, being one of the largest and deepest ice-free natural harbours in the world. Before Confederation it was one of the most important commercial ports on the Atlantic seaboard. In 1917, it was the site of the world's largest man-made accidental explosion, when the blew up in the Halifax Explosion of December 6. The harbour was formed by a drowned glacial valley which succumbed to sea level rise after glaciation. The Sackville River now empties into the upper end of the harbour in Bedford Basin. The harbour also includes the Northwest Arm and The Narrows, a constricted passage to Bedford Basin Halifax Harbour has been polluted as a result of two centuries of direct raw sewage discharge into its waters. Health concerns in the 1990s caused the shut-down of all harbour beaches. The Harbour Solutions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Canadian Navy
The Royal Canadian Navy (RCN; french: Marine royale canadienne, ''MRC'') is the Navy, naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack submarines, 12 coastal defence vessels, eight patrol class training vessels, two offshore patrol vessels, and several auxiliary vessels. The RCN consists of 8,570 Regular Force and 4,111 Primary Reserve sailors, supported by 3,800 civilians. Vice-Admiral Angus Topshee is the current commander of the Royal Canadian Navy and chief of the Naval Staff. Origins of the Royal Canadian Navy, Founded in 1910 as the Naval Service of Canada (French: ''Service naval du Canada'') and given royal sanction on 29 August 1911, the RCN was amalgamated with the Royal Canadian Air Force and the Canadian Army to form the Unification of the Canadian Forces, unified Canadian Armed Forces in 1968, after which it was known as Maritime Command (French: ''Commandemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
