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41 Summenfehler
Summenfehler m cumulative errorDeutsch-Englisch Wörterbuch der Elektrotechnik und Elektronik > Summenfehler
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42 Harrison, John
[br]b. 24 March 1693 Foulby, Yorkshire, Englandd. 24 March 1776 London, England[br]English horologist who constructed the first timekeeper of sufficient accuracy to determine longitude at sea and invented the gridiron pendulum for temperature compensation.[br]John Harrison was the son of a carpenter and was brought up to that trade. He was largely self-taught and learned mechanics from a copy of Nicholas Saunderson's lectures that had been lent to him. With the assistance of his younger brother, James, he built a series of unconventional clocks, mainly of wood. He was always concerned to reduce friction, without using oil, and this influenced the design of his "grasshopper" escapement. He also invented the "gridiron" compensation pendulum, which depended on the differential expansion of brass and steel. The excellent performance of his regulator clocks, which incorporated these devices, convinced him that they could also be used in a sea dock to compete for the longitude prize. In 1714 the Government had offered a prize of £20,000 for a method of determining longitude at sea to within half a degree after a voyage to the West Indies. In theory the longitude could be found by carrying an accurate timepiece that would indicate the time at a known longitude, but the requirements of the Act were very exacting. The timepiece would have to have a cumulative error of no more than two minutes after a voyage lasting six weeks.In 1730 Harrison went to London with his proposal for a sea clock, supported by examples of his grasshopper escapement and his gridiron pendulum. His proposal received sufficient encouragement and financial support, from George Graham and others, to enable him to return to Barrow and construct his first sea clock, which he completed five years later. This was a large and complicated machine that was made out of brass but retained the wooden wheelwork and the grasshopper escapement of the regulator clocks. The two balances were interlinked to counteract the rolling of the vessel and were controlled by helical springs operating in tension. It was the first timepiece with a balance to have temperature compensation. The effect of temperature change on the timekeeping of a balance is more pronounced than it is for a pendulum, as two effects are involved: the change in the size of the balance; and the change in the elasticity of the balance spring. Harrison compensated for both effects by using a gridiron arrangement to alter the tension in the springs. This timekeeper performed creditably when it was tested on a voyage to Lisbon, and the Board of Longitude agreed to finance improved models. Harrison's second timekeeper dispensed with the use of wood and had the added refinement of a remontoire, but even before it was tested he had embarked on a third machine. The balance of this machine was controlled by a spiral spring whose effective length was altered by a bimetallic strip to compensate for changes in temperature. In 1753 Harrison commissioned a London watchmaker, John Jefferys, to make a watch for his own personal use, with a similar form of temperature compensation and a modified verge escapement that was intended to compensate for the lack of isochronism of the balance spring. The time-keeping of this watch was surprisingly good and Harrison proceeded to build a larger and more sophisticated version, with a remontoire. This timekeeper was completed in 1759 and its performance was so remarkable that Harrison decided to enter it for the longitude prize in place of his third machine. It was tested on two voyages to the West Indies and on both occasions it met the requirements of the Act, but the Board of Longitude withheld half the prize money until they had proof that the timekeeper could be duplicated. Copies were made by Harrison and by Larcum Kendall, but the Board still continued to prevaricate and Harrison received the full amount of the prize in 1773 only after George III had intervened on his behalf.Although Harrison had shown that it was possible to construct a timepiece of sufficient accuracy to determine longitude at sea, his solution was too complex and costly to be produced in quantity. It had, for example, taken Larcum Kendall two years to produce his copy of Harrison's fourth timekeeper, but Harrison had overcome the psychological barrier and opened the door for others to produce chronometers in quantity at an affordable price. This was achieved before the end of the century by Arnold and Earnshaw, but they used an entirely different design that owed more to Le Roy than it did to Harrison and which only retained Harrison's maintaining power.[br]Principal Honours and DistinctionsRoyal Society Copley Medal 1749.Bibliography1767, The Principles of Mr Harrison's Time-keeper, with Plates of the Same, London. 1767, Remarks on a Pamphlet Lately Published by the Rev. Mr Maskelyne Under theAuthority of the Board of Longitude, London.1775, A Description Concerning Such Mechanisms as Will Afford a Nice or True Mensuration of Time, London.Further ReadingR.T.Gould, 1923, The Marine Chronometer: Its History and Development, London; reprinted 1960, Holland Press.—1978, John Harrison and His Timekeepers, 4th edn, London: National Maritime Museum.H.Quill, 1966, John Harrison, the Man who Found Longitude, London. A.G.Randall, 1989, "The technology of John Harrison's portable timekeepers", Antiquarian Horology 18:145–60, 261–77.J.Betts, 1993, John Harrison London (a good short account of Harrison's work). S.Smiles, 1905, Men of Invention and Industry; London: John Murray, Chapter III. Dictionary of National Biography, Vol. IX, pp. 35–6.DV -
43 sumaryczny błąd podziatki
• cumulative pitch errorSłownik polsko-angielski dla inżynierów > sumaryczny błąd podziatki
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44 errore di passo cumulativo
"cumulative pitch error;Summenteilungsfehler;Gesamtteilungsfehler;soma dos erros da divisão" -
45 накопленная погрешность шага
1) Automation: accumulative pitch error, cumulative pitch error, cumulative pitch variation, index variation, total cumulative pitch error2) Makarov: accumulated pitch variationУниверсальный русско-английский словарь > накопленная погрешность шага
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46 накопленная погрешность шага
accumulative pitch error, cumulative pitch error, total cumulative pitch error, cumulative pitch variationРусско-английский исловарь по машиностроению и автоматизации производства > накопленная погрешность шага
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47 погрешность
(см. также ошибка)погрешность выхода — output error, yield errorПоставки машин и оборудования. Русско-английский словарь > погрешность
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48 накопленная погрешность шага зацепления
Automation: cumulative base pitch error, cumulative gear meshing errorУниверсальный русско-английский словарь > накопленная погрешность шага зацепления
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49 метод
method; techniqueприменять новые методы — to employ / to practise new methods
решать волюнтаристскими методами — to solve (smth.) by voluntaristic methods
административно-командный / командно-административный метод — administrative-command / command-administrative method
метод оценивания — estimating method, method of estimation
метод проб и ошибок — trial-and-error / try-and-error method
метод прогнозирования — forecast(ing) / prediction method
метод управления — management / managerial method
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50 частота
1. rate2. frequencyзвуковая, низкая частота — audio frequency
Синонимический ряд:густота (сущ.) густота; плотность -
51 накопленная погрешность k шагов зубчатой рейки
Automation: cumulative pitch error of k pitches of the rackУниверсальный русско-английский словарь > накопленная погрешность k шагов зубчатой рейки
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52 накопленная погрешность k шагов червяка
Automation: cumulative pitch error of k pitches of a wormУниверсальный русско-английский словарь > накопленная погрешность k шагов червяка
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53 kumulativer Überdeckungsfehler
Deutsch-Englisch Wörterbuch der Elektrotechnik und Elektronik > kumulativer Überdeckungsfehler
См. также в других словарях:
cumulative error — sukauptoji paklaida statusas T sritis fizika atitikmenys: angl. accumulated error; cumulative error vok. akkumulierter Fehler, m; angesammelter Fehler, m rus. накопленная погрешность, f pranc. erreur d’accumulation, f … Fizikos terminų žodynas
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accumulated error — sukauptoji paklaida statusas T sritis fizika atitikmenys: angl. accumulated error; cumulative error vok. akkumulierter Fehler, m; angesammelter Fehler, m rus. накопленная погрешность, f pranc. erreur d’accumulation, f … Fizikos terminų žodynas
Rounding Error — A mathematical miscalculation caused by altering a number to an integer or one with fewer decimals. The significance of rounding error depends on the circumstances. While it is inconsequential enough to be ignored in most cases, rounding error… … Investment dictionary
Verlet integration — (IPA all|veʁ le) is a method used to integrate Newton s equations of motion. It is frequently used to calculate trajectories of particles in molecular dynamics simulations and video games. The verlet integrator offers greater stability than the… … Wikipedia