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41 Ricardo, Sir Harry Ralph
[br]b. 26 January 1885 London, Englandd. 18 May 1974 Graffham, Sussex, England[br]English mechanical engineer; researcher, designer and developer of internal combustion engines.[br]Harry Ricardo was the eldest child and only son of Halsey Ricardo (architect) and Catherine Rendel (daughter of Alexander Rendel, senior partner in the firm of consulting civil engineers that later became Rendel, Palmer and Tritton). He was educated at Rugby School and at Cambridge. While still at school, he designed and made a steam engine to drive his bicycle, and by the time he went up to Cambridge in 1903 he was a skilled craftsman. At Cambridge, he made a motor cycle powered by a petrol engine of his own design, and with this he won a fuel-consumption competition by covering almost 40 miles (64 km) on a quart (1.14 1) of petrol. This brought him to the attention of Professor Bertram Hopkinson, who invited him to help with research on turbulence and pre-ignition in internal combustion engines. After leaving Cambridge in 1907, he joined his grandfather's firm and became head of the design department for mechanical equipment used in civil engineering. In 1916 he was asked to help with the problem of loading tanks on to railway trucks. He was then given the task of designing and organizing the manufacture of engines for tanks, and the success of this enterprise encouraged him to set up his own establishment at Shoreham, devoted to research on, and design and development of, internal combustion engines.Leading on from the work with Hopkinson were his discoveries on the suppression of detonation in spark-ignition engines. He noted that the current paraffinic fuels were more prone to detonation than the aromatics, which were being discarded as they did not comply with the existing specifications because of their high specific gravity. He introduced the concepts of "highest useful compression ratio" (HUCR) and "toluene number" for fuel samples burned in a special variable compression-ratio engine. The toluene number was the proportion of toluene in heptane that gave the same HUCR as the fuel sample. Later, toluene was superseded by iso-octane to give the now familiar octane rating. He went on to improve the combustion in side-valve engines by increasing turbulence, shortening the flame path and minimizing the clearance between piston and head by concentrating the combustion space over the valves. By these means, the compression ratio could be increased to that used by overhead-valve engines before detonation intervened. The very hot poppet valve restricted the advancement of all internal combustion engines, so he turned his attention to eliminating it by use of the single sleeve-valve, this being developed with support from the Air Ministry. By the end of the Second World War some 130,000 such aero-engines had been built by Bristol, Napier and Rolls-Royce before the piston aero-engine was superseded by the gas turbine of Whittle. He even contributed to the success of the latter by developing a fuel control system for it.Concurrent with this was work on the diesel engine. He designed and developed the engine that halved the fuel consumption of London buses. He invented and perfected the "Comet" series of combustion chambers for diesel engines, and the Company was consulted by the vast majority of international internal combustion engine manufacturers. He published and lectured widely and fully deserved his many honours; he was elected FRS in 1929, was President of the Institution of Mechanical Engineers in 1944–5 and was knighted in 1948. This shy and modest, though very determined man was highly regarded by all who came into contact with him. It was said that research into internal combustion engines, his family and boats constituted all that he would wish from life.[br]Principal Honours and DistinctionsKnighted 1948. FRS 1929. President, Institution of Mechanical Engineers 1944–5.Bibliography1968, Memo \& Machines. The Pattern of My Life, London: Constable.Further ReadingSir William Hawthorne, 1976, "Harry Ralph Ricardo", Biographical Memoirs of Fellows of the Royal Society 22.JBBiographical history of technology > Ricardo, Sir Harry Ralph
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42 Riefler, Sigmund
SUBJECT AREA: Horology[br]b. 9 August 1847 Maria Rain, Germanyd. 21 October 1912 Munich, Germany[br]German engineer who invented the precision clock that bears his name.[br]Riefler's father was a scientific-instrument maker and clockmaker who in 1841 had founded the firm of Clemens Riefler to make mathematical instruments. After graduating in engineering from the University of Munich Sigmund worked as a surveyor, but when his father died in 1876 he and his brothers ran the family firm. Sigmund was responsible for technical development and in this capacity he designed a new system of drawing-instruments which established the reputation of the firm. He also worked to improve the performance of the precision clock, and in 1889 he was granted a patent for a new form of escapement. This escapement succeeded in reducing the interference of the clock mechanism with the free swinging of the pendulum by impulsing the pendulum through its suspension strip. It proved to be the greatest advance in precision timekeeping since the introduction of the dead-beat escapement about two hundred years earlier. When the firm of Clemens Riefler began to produce clocks with this escapement in 1890, they replaced clocks with Graham's dead-beat escapement as the standard regulator for use in observatories and other applications where the highest precision was required. In 1901 a movement was fitted with electrical rewind and was encapsulated in an airtight case, at low pressure, so that the timekeeping was not affected by changes in barometric pressure. This became the standard practice for precision clocks. Although the accuracy of the Riefler clock was later surpassed by the Shortt free-pendulum clock and the quartz clock, it remained in production until 1965, by which time over six hundred instruments had been made.[br]Principal Honours and DistinctionsFranklin Institute John Scott Medal 1894. Honorary doctorate, University of Munich 1897. Vereins zur Förderung des Gewerbefleisses in Preussen Gold Medal 1900.Bibliography1907, Präzisionspendeluhren und Zeitdienstanlagen fürSternwarten, Munich (for a complete bibliography see D.Riefler below).Further ReadingD.Riefler, 1981, Riefler-Präzisionspendeluhren, Munich (the definitive work on Riefler and his clock).A.L.Rawlings, 1948, The Science of Clocks and Watches, 2nd edn; repub. 1974 (a technical assessment of the Riefler escapement in its historical context).See also: Marrison, Warren AlvinDV -
43 ὑπέρακμος
ὑπέρακμος, ον (Soranus, Hesych., Suda) fr. ἀκμή=highest point or prime of a person’s development (ἀκ. in this sense in Pla., Rep. 5, 460e; Philo, Leg. All. 1, 10) in our lit. only 1 Cor 7:36. Depending on one’s understanding of this pass. (s. γαμίζω) the term may apply either to a woman or to a man.① Understood temporally and as a status term applied to a woman: past one’s prime, past marriageable age, past the bloom of youth (cp. Soranus p. 15, 8.—Diod S 32, 11, 1 speaks of the ἀκμὴ τῆς ἡλικίας of a woman and in 34 + 35 Fgm. 2, 39 uses ἀκμή of the youthful bloom of a παρθένος.—Lycon [III B.C.], Fgm. 27 Wehrli [in Diog. L. 5, 65], commiserates the father of a παρθένος who, because of the smallness of her dowry ἐκτρέχουσα [=goes beyond] τὸν ἀκμαῖον τῆς ἡλικίας καιρόν). So e.g. Tyndale, Phillips, KJV, Jerusalem Bible.② Other interpreters focus on the ascensive force of ὑπέρ, ‘exceedingly’ (freq. found in compounds, as in ὑπέρκαλος ‘exceedingly beautiful’ and related terms Pollux 3, 71). In our pass., then, ὑπέρακμος means at one’s sexual peak and may be applied to a woman (so, apparently, L-S-J-M ‘sexually well developed’) or to a man (cp. Diod S 36, 2, 3 ὁ ἔρως of a man in love ἤκμαζεν and became irresistible), with strong passions (REB and NRSV ‘if his passions are strong’).—Cp. DELG s.v. ἀκ-p. 44. M-M.
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