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81 rotor
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82 thrust
тяга; сила тяги; осевое давление; импульс; создавать тягу или импульсstart in reverse thrust — запускать (двигатель) в режиме реверса тяги [при включенном реверсе]
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83 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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84 Memory
To what extent can we lump together what goes on when you try to recall: (1) your name; (2) how you kick a football; and (3) the present location of your car keys? If we use introspective evidence as a guide, the first seems an immediate automatic response. The second may require constructive internal replay prior to our being able to produce a verbal description. The third... quite likely involves complex operational responses under the control of some general strategy system. Is any unitary search process, with a single set of characteristics and inputoutput relations, likely to cover all these cases? (Reitman, 1970, p. 485)[Semantic memory] Is a mental thesaurus, organized knowledge a person possesses about words and other verbal symbols, their meanings and referents, about relations among them, and about rules, formulas, and algorithms for the manipulation of these symbols, concepts, and relations. Semantic memory does not register perceptible properties of inputs, but rather cognitive referents of input signals. (Tulving, 1972, p. 386)The mnemonic code, far from being fixed and unchangeable, is structured and restructured along with general development. Such a restructuring of the code takes place in close dependence on the schemes of intelligence. The clearest indication of this is the observation of different types of memory organisation in accordance with the age level of a child so that a longer interval of retention without any new presentation, far from causing a deterioration of memory, may actually improve it. (Piaget & Inhelder, 1973, p. 36)4) The Logic of Some Memory Theorization Is of Dubious Worth in the History of PsychologyIf a cue was effective in memory retrieval, then one could infer it was encoded; if a cue was not effective, then it was not encoded. The logic of this theorization is "heads I win, tails you lose" and is of dubious worth in the history of psychology. We might ask how long scientists will puzzle over questions with no answers. (Solso, 1974, p. 28)We have iconic, echoic, active, working, acoustic, articulatory, primary, secondary, episodic, semantic, short-term, intermediate-term, and longterm memories, and these memories contain tags, traces, images, attributes, markers, concepts, cognitive maps, natural-language mediators, kernel sentences, relational rules, nodes, associations, propositions, higher-order memory units, and features. (Eysenck, 1977, p. 4)The problem with the memory metaphor is that storage and retrieval of traces only deals [ sic] with old, previously articulated information. Memory traces can perhaps provide a basis for dealing with the "sameness" of the present experience with previous experiences, but the memory metaphor has no mechanisms for dealing with novel information. (Bransford, McCarrell, Franks & Nitsch, 1977, p. 434)7) The Results of a Hundred Years of the Psychological Study of Memory Are Somewhat DiscouragingThe results of a hundred years of the psychological study of memory are somewhat discouraging. We have established firm empirical generalisations, but most of them are so obvious that every ten-year-old knows them anyway. We have made discoveries, but they are only marginally about memory; in many cases we don't know what to do with them, and wear them out with endless experimental variations. We have an intellectually impressive group of theories, but history offers little confidence that they will provide any meaningful insight into natural behavior. (Neisser, 1978, pp. 12-13)A schema, then is a data structure for representing the generic concepts stored in memory. There are schemata representing our knowledge about all concepts; those underlying objects, situations, events, sequences of events, actions and sequences of actions. A schema contains, as part of its specification, the network of interrelations that is believed to normally hold among the constituents of the concept in question. A schema theory embodies a prototype theory of meaning. That is, inasmuch as a schema underlying a concept stored in memory corresponds to the mean ing of that concept, meanings are encoded in terms of the typical or normal situations or events that instantiate that concept. (Rumelhart, 1980, p. 34)Memory appears to be constrained by a structure, a "syntax," perhaps at quite a low level, but it is free to be variable, deviant, even erratic at a higher level....Like the information system of language, memory can be explained in part by the abstract rules which underlie it, but only in part. The rules provide a basic competence, but they do not fully determine performance. (Campbell, 1982, pp. 228, 229)When people think about the mind, they often liken it to a physical space, with memories and ideas as objects contained within that space. Thus, we speak of ideas being in the dark corners or dim recesses of our minds, and of holding ideas in mind. Ideas may be in the front or back of our minds, or they may be difficult to grasp. With respect to the processes involved in memory, we talk about storing memories, of searching or looking for lost memories, and sometimes of finding them. An examination of common parlance, therefore, suggests that there is general adherence to what might be called the spatial metaphor. The basic assumptions of this metaphor are that memories are treated as objects stored in specific locations within the mind, and the retrieval process involves a search through the mind in order to find specific memories....However, while the spatial metaphor has shown extraordinary longevity, there have been some interesting changes over time in the precise form of analogy used. In particular, technological advances have influenced theoretical conceptualisations.... The original Greek analogies were based on wax tablets and aviaries; these were superseded by analogies involving switchboards, gramophones, tape recorders, libraries, conveyor belts, and underground maps. Most recently, the workings of human memory have been compared to computer functioning... and it has been suggested that the various memory stores found in computers have their counterparts in the human memory system. (Eysenck, 1984, pp. 79-80)Primary memory [as proposed by William James] relates to information that remains in consciousness after it has been perceived, and thus forms part of the psychological present, whereas secondary memory contains information about events that have left consciousness, and are therefore part of the psychological past. (Eysenck, 1984, p. 86)Once psychologists began to study long-term memory per se, they realized it may be divided into two main categories.... Semantic memories have to do with our general knowledge about the working of the world. We know what cars do, what stoves do, what the laws of gravity are, and so on. Episodic memories are largely events that took place at a time and place in our personal history. Remembering specific events about our own actions, about our family, and about our individual past falls into this category. With amnesia or in aging, what dims... is our personal episodic memories, save for those that are especially dear or painful to us. Our knowledge of how the world works remains pretty much intact. (Gazzaniga, 1988, p. 42)The nature of memory... provides a natural starting point for an analysis of thinking. Memory is the repository of many of the beliefs and representations that enter into thinking, and the retrievability of these representations can limit the quality of our thought. (Smith, 1990, p. 1)Historical dictionary of quotations in cognitive science > Memory
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