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1 gridiron pendulum
grid.i.ron pen.du.lum[gr'idaiən pendjuləm] n pêndulo compensado. -
2 gridiron pendulum
s.péndulo de compensación. -
3 harrisons gridiron pendulum
அரிசனினிரும்பளியடைப்பூசல் -
4 gridiron
grid·iron[ˈgrɪdaɪən, AM -aɪɚn]n* * *['grId"aɪən]n* * *gridiron [ˈɡrıdˌaıə(r)n] s1. Bratrost m2. Gitter(rost) n(m), -werk n3. Netz(werk) n (von Leitungen, Bahnlinien etc)4. SCHIFF Balkenroste f5. THEAT Schnürboden m* * *n.Bratrost n.Rost -e m. -
5 gridiron
s 1. roštilj (za prženje mesa); 2. [hist] rešetka za mučenje; 3. [mar] okvir od usporednih greda koje podupiru brod u suhom doku; [mar & mil] dvostruka fronta (vrsta bojne formacije); 4. [theat] užište; 5. [rly] niz usporednih kolosijeka za razvrstavanje vagona; 6. [el] mreža vodova visoke napetosti; 7. [tech] kompenzacijsko njihalo ( # pendulum); 8. [US] igralište amer. ragbija* * *
rešetka -
6 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 -
7 Guillaume, Charles-Edouard
[br]b. 15 February 1861 Fleurier, Switzerlandd. 13 June 1938 Sèvres, France[br]Swiss physicist who developed two alloys, "invar" and "elinvar", used for the temperature compensation of clocks and watches.[br]Guillaume came from a family of clock-and watchmakers. He was educated at the Gymnasium in Neuchâtel and at Zurich Polytechnic, from which he received his doctorate in 1883 for a thesis on electrolytic capacitors. In the same year he joined the International Bureau of Weights and Measures at Sèvres in France, where he was to spend the rest of his working life. He retired as Director in 1936. At the bureau he was involved in distributing the national standards of the metre to countries subscribing to the General Conference on Weights and Measures that had been held in 1889. This made him aware of the crucial effect of thermal expansion on the lengths of the standards and he was prompted to look for alternative materials that would be less costly than the platinum alloys which had been used. While studying nickel steels he made the surprising discovery that the thermal expansion of certain alloy compositions was less than that of the constituent metals. This led to the development of a steel containing about 36 per cent nickel that had a very low thermal coefficient of expansion. This alloy was subsequently named "invar", an abbreviation of invariable. It was well known that changes in temperature affected the timekeeping of clocks by altering the length of the pendulum, and various attempts had been made to overcome this defect, most notably the mercury-compensated pendulum of Graham and the gridiron pendulum of Harrison. However, an invar pendulum offered a simpler and more effective method of temperature compensation and was used almost exclusively for pendulum clocks of the highest precision.Changes in temperature can also affect the timekeeping of watches and chronometers, but this is due mainly to changes in the elasticity or stiffness of the balance spring rather than to changes in the size of the balance itself. To compensate for this effect Guillaume developed another more complex nickel alloy, "elinvar" (elasticity invariable), whose elasticity remained almost constant with changes in temperature. This had two practical consequences: the construction of watches could be simplified (by using monometallic balances) and more accurate chronometers could be made.[br]Principal Honours and DistinctionsNobel Prize for Physics 1920. Corresponding member of the Académie des Sciences. Grand Officier de la Légion d'honneur 1937. Physical Society Duddell Medal 1928. British Horological Institute Gold Medal 1930.Bibliography1897, "Sur la dilation des aciers au nickel", Comptes rendus hebdomadaires des séances de l'Académie des sciences 124:176.1903, "Variations du module d"élasticité des aciers au nickel', Comptes rendushebdomadaires des séances de l'Académie des sciences 136:498."Les aciers au nickel et leurs applications à l'horlogerie", in J.Grossmann, Horlogerie théorique, Paris, Vol. II, pp. 361–414 (describes the application of invar and elinvar to horology).Sir Richard Glazebrook (ed.), 1923 "Invar and Elinvar", Dictionary of Applied Physics, 5 vols, London, Vol. V, pp. 320–7 (a succinct account in English).Further ReadingR.M.Hawthorne, 1989, Nobel Prize Winners, Physics, 1901–1937, ed. F.N.Magill, Pasadena, Salem Press, pp. 244–51.See also: Le Roy, PierreDVBiographical history of technology > Guillaume, Charles-Edouard
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8 fly
летать глагол:напуститься (fly, fall)имя существительное:расстояние полета (fly, flight)имя прилагательное:
См. также в других словарях:
Gridiron pendulum — Gridiron Grid i ron, n. [OE. gredire, gredirne, from the same source as E. griddle, but the ending was confused with E. iron. See {Griddle}.] 1. A grated iron utensil for broiling flesh and fish over coals. [1913 Webster] 2. (Naut.) An openwork… … The Collaborative International Dictionary of English
Gridiron pendulum — The gridiron pendulum was an improvement of clock pendulums invented by John Harrison, consisting of alternating zinc and iron rods assembled so that their different thermal expansions (or contractions) cancel each other out. Its simplest form… … Wikipedia
gridiron pendulum — noun : a compensation pendulum in which the unequal expansion of two different metals is utilized to maintain constant effective pendulum length * * * a clock pendulum having, as part of its shaft, an arrangement of brass and steel rods having… … Useful english dictionary
gridiron pendulum — a clock pendulum having, as part of its shaft, an arrangement of brass and steel rods having different coefficients of expansion, such that the pendulum has the same length at any temperature. [1745 55] * * * … Universalium
Gridiron — may refer to: * Gridiron (cooking), type of grill that can be used to cook meat or other food over a fire; most of the other usages derive from this term due to their fancied resemblance * Gridiron plan, in urban planning, a system that describes … Wikipedia
Gridiron — Grid i ron, n. [OE. gredire, gredirne, from the same source as E. griddle, but the ending was confused with E. iron. See {Griddle}.] 1. A grated iron utensil for broiling flesh and fish over coals. [1913 Webster] 2. (Naut.) An openwork frame on… … The Collaborative International Dictionary of English
Gridiron valve — Gridiron Grid i ron, n. [OE. gredire, gredirne, from the same source as E. griddle, but the ending was confused with E. iron. See {Griddle}.] 1. A grated iron utensil for broiling flesh and fish over coals. [1913 Webster] 2. (Naut.) An openwork… … The Collaborative International Dictionary of English
Pendulum — Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the movements … The Collaborative International Dictionary of English
Pendulum bob — Pendulum Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the… … The Collaborative International Dictionary of English
Pendulum level — Pendulum Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the… … The Collaborative International Dictionary of English
Pendulum wheel — Pendulum Pen du*lum, n.; pl. {Pendulums}. [NL., fr. L. pendulus hanging, swinging. See {Pendulous}.] A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the… … The Collaborative International Dictionary of English
