task-based

the most effective and efficient method of achieving any objective or task. What constitutes best practice can be determined through a process of benchmarking. An organization can move toward achieving best practice, either across the whole organization or in a specific area, through continuous improvement. In production-based organizations, world class manufacturing is a related concept. More generally, a market or sector leader may be described as best-in-class.

a factor that determines the cost of an activity. Cost drivers are analyzed as part of activity based costing and can be used in continuous improvement programs. They are usually assessed together as multiple drivers rather than singly. There are two main types of cost driver: the first is a resource driver, which refers to the contribution of the quantity of resources used to the cost of an activity; the second is an activity driver, which refers to the costs incurred by the activities required to complete a particular task or project.

a model for analyzing management change, developed by Harold J. Leavitt. Leavitt’s Diamond is based on the idea that it is rare for any change to occur in isolation. Leavitt sees technology, tasks, people, and the organizational structure in which they function as four interdependent variables, visualized as the four points of a diamond. Change at any one point of the diamond will impact some or all of the others. Thus, a changed task will necessarily affect the people involved in it, the structure in which they work, and the technology that they use. Failure to manage these interdependencies at critical times of change can create problems.

See also change management

a sophisticated production planning and control system, based on finite loading procedures, that concentrates on reducing bottlenecks in the system in order to improve efficiency. The key task of OPT is to increase total systems throughput by realizing existing capacity in other parts of the system. OPT is a practical application of the theory of constraints.

Abbr. OPT

SUBJECT AREA: Mining and extraction technology

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The son of a Hamburg merchant, he studied mechanical engineering at the Polytechnikum in Zurich and was engaged in constructing a railway line in Hungary and Austria before he returned to Switzerland. At Airolo, where the Gotthard tunnel was to commence, he designed a hydraulic rock drill; the pneumatic ones, similar to the Ingersoll type, did not satisfy him. His drill consisted of two parts instead of three: the hydraulic motor and the installation for drilling. At the Sulzer company of Winterthur his first design, a percussion drill, in 1876, was developed into a rotary drill which worked with greatest success in the construction of various railway tunnels and also helped to reduce costs in the mining industry.

His Hamburg-based firm Brandt \& Brandau consequently was soon engaged in many tunnelling and mining projects throughout Germany, as well as abroad. During the years 1883 and 1895 Brandt spent time in exploration in Spain and reopening the lead-mines in Posada. His most ambitious task was to co-operate in drafting the Simplon tunnel, the construction of which relied greatly on his knowledge and expertise. The works began several years behind schedule, in 1898, and consequently he was unable to see its completion.

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SUBJECT AREA: Land transport, Railways and locomotives

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Chapelon's technical education at the Ecole Centrale des Arts et Manufactures, Paris, was interrupted by extended military service during the First World War. From experience of observing artillery from the basket of a captive balloon, he developed a method of artillery fire control which was more accurate than that in use and which was adopted by the French army.

In 1925 he joined the motive-power and rolling-stock department of the Paris-Orléans Railway under Chief Mechanical Engineer Maurice Lacoin and was given the task of improving the performance of its main-line 4–6–2 locomotives, most of them compounds. He had already made an intensive study of steam locomotive design and in 1926 introduced his Kylchap exhaust system, based in part on the earlier work of the Finnish engineer Kyläla. Chapelon improved the entrainment of the hot gases in the smokebox by the exhaust steam and so minimized back pressure in the cylinders, increasing the power of a locomotive substantially. He also greatly increased the cross-sectional area of steam passages, used poppet valves instead of piston valves and increased superheating of steam. PO (Paris-Orléans) 4–6–2s rebuilt on these principles from 1929 onwards proved able to haul 800-ton trains, in place of the previous 500-ton trains, and to do so to accelerated schedules with reduced coal consumption. Commencing in 1932, some were converted, at the time of rebuilding, into 4–8–0s to increase adhesive weight for hauling heavy trains over the steeply graded Paris-Toulouse line.

Chapelon's principles were quickly adopted on other French railways and elsewhere.

H.N. Gresley was particularly influenced by them. After formation of the French National Railways (SNCF) in 1938, Chapelon produced in 1941 a prototype rebuilt PO 2–10–0 freight locomotive as a six-cylinder compound, with four low-pressure cylinders to maximize expansive use of steam and with all cylinders steam-jacketed to minimize heat loss by condensation and radiation. War conditions delayed extended testing until 1948–52. Meanwhile Chapelon had, by rebuilding, produced in 1946 a high-powered, three-cylinder, compound 4–8–4 intended as a stage in development of a proposed range of powerful and thermally efficient steam locomotives for the postwar SNCF: a high-speed 4–6–4 in this range was to run at sustained speeds of 125 mph (200 km/h). However, plans for improved steam locomotives were then overtaken in France by electriflcation and dieselization, though the performance of the 4–8–4, which produced 4,000 hp (3,000 kW) at the drawbar for the first time in Europe, prompted modification of electric locomotives, already on order, to increase their power.

Chapelon retired from the SNCF in 1953, but continued to act as a consultant. His principles were incorporated into steam locomotives built in France for export to South America, and even after the energy crisis of 1973 he was consulted on projects to build improved, high-powered steam locomotives for countries with reserves of cheap coal. The eventual fall in oil prices brought these to an end.

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SUBJECT AREA: Agricultural and food technology

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Ferguson's father was a small farmer who expected his son to help on the farm from an early age. As a result he received little formal education, and on leaving school joined his brother in a backstreet workshop in Belfast repairing motor bikes. By the age of 19 he had built his own bike and began hill-climbing competitions and racing. His successes in these ventures gained useful publicity for the workshop. In 1907 he built his own car and entered it into competitions, and in 1909 became the first person in Britain to build and fly a machine that was heavier than air.

On the outbreak of the First World War he was appointed by the Irish Department of Agriculture to supervise the operation and maintenance of all farm tractors. His experiences convinced him that even the Ford tractor and the implements available for it were inadequate for the task, and he began to experiment with his own plough designs. The formation of the Ferguson-Sherman Corporation resulted in the production of thousands of the ploughs he had designed for the Ford tractor, but in 1928 Ford discontinued production of tractors, and Ferguson returned to Ireland. He immediately began to design his own tractor. Six years of development led to the building of a prototype that weighed only 16 cwt (813kg). In 1936 David Brown of Huddersfield, Yorkshire, began production of these tractors for Ferguson, but the partnership was not wholly successful and was dissolved after three years. In 1939 Ferguson and Ford reached their famous "Handshake agreement", in which no formal contract was signed, and the mass production of the Ford Ferguson system tractors began that year. During the next nine years 300,000 tractors and a million implements were produced under this agreement. However, on the death of Henry Ford the company began production, under his son, of their own tractor. Ferguson returned to the UK and negotiated a deal with the Standard Motor Company of Coventry for the production of his tractor. At the same time he took legal action against Ford, which resulted in that company being forced to stop production and to pay damages amounting to US$9.5 million.

Aware that his equipment would only operate when set up properly, Ferguson established a training school at Stoneleigh in Warwickshire which was to be a model for other manufacturers. In 1953, by amicable agreement, Ferguson amalgamated with the Massey Harris Company to form Massey Ferguson, and in so doing added harvesting machinery to the range of equipment produced. A year later he disposed of his shares in the new company and turned his attention again to the motor car. Although a number of experimental cars were produced, there were no long-lasting developments from this venture other than a four-wheel-drive system based on hydraulics; this was used by a number of manufacturers on occasional models. Ferguson's death heralded the end of these developments.

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SUBJECT AREA: Land transport, Railways and locomotives

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George Stephenson was the son of the fireman of the pumping engine at Wylam colliery, and horses drew wagons of coal along the wooden rails of the Wylam wagonway past the house in which he was born and spent his earliest childhood. While still a child he worked as a cowherd, but soon moved to working at coal pits. At 17 years of age he showed sufficient mechanical talent to be placed in charge of a new pumping engine, and had already achieved a job more responsible than that of his father. Despite his position he was still illiterate, although he subsequently learned to read and write. He was largely self-educated.

In 1801 he was appointed Brakesman of the winding engine at Black Callerton pit, with responsibility for lowering the miners safely to their work. Then, about two years later, he became Brakesman of a new winding engine erected by Robert Hawthorn at Willington Quay on the Tyne. Returning collier brigs discharged ballast into wagons and the engine drew the wagons up an inclined plane to the top of "Ballast Hill" for their contents to be tipped; this was one of the earliest applications of steam power to transport, other than experimentally.

In 1804 Stephenson moved to West Moor pit, Killingworth, again as Brakesman. In 1811 he demonstrated his mechanical skill by successfully modifying a new and unsatisfactory atmospheric engine, a task that had defeated the efforts of others, to enable it to pump a drowned pit clear of water. The following year he was appointed Enginewright at Killingworth, in charge of the machinery in all the collieries of the "Grand Allies", the prominent coal-owning families of Wortley, Liddell and Bowes, with authorization also to work for others. He built many stationary engines and he closely examined locomotives of John Blenkinsop's type on the Kenton \& Coxlodge wagonway, as well as those of William Hedley at Wylam.

It was in 1813 that Sir Thomas Liddell requested George Stephenson to build a steam locomotive for the Killingworth wagonway: Blucher made its first trial run on 25 July 1814 and was based on Blenkinsop's locomotives, although it lacked their rack-and-pinion drive. George Stephenson is credited with building the first locomotive both to run on edge rails and be driven by adhesion, an arrangement that has been the conventional one ever since. Yet Blucher was far from perfect and over the next few years, while other engineers ignored the steam locomotive, Stephenson built a succession of them, each an improvement on the last.

During this period many lives were lost in coalmines from explosions of gas ignited by miners' lamps. By observation and experiment (sometimes at great personal risk) Stephenson invented a satisfactory safety lamp, working independently of the noted scientist Sir Humphry Davy who also invented such a lamp around the same time.

In 1817 George Stephenson designed his first locomotive for an outside customer, the Kilmarnock \& Troon Railway, and in 1819 he laid out the Hetton Colliery Railway in County Durham, for which his brother Robert was Resident Engineer. This was the first railway to be worked entirely without animal traction: it used inclined planes with stationary engines, self-acting inclined planes powered by gravity, and locomotives.

On 19 April 1821 Stephenson was introduced to Edward Pease, one of the main promoters of the Stockton \& Darlington Railway (S \& DR), which by coincidence received its Act of Parliament the same day. George Stephenson carried out a further survey, to improve the proposed line, and in this he was assisted by his 18-year-old son, Robert Stephenson, whom he had ensured received the theoretical education which he himself lacked. It is doubtful whether either could have succeeded without the other; together they were to make the steam railway practicable.

At George Stephenson's instance, much of the S \& DR was laid with wrought-iron rails recently developed by John Birkinshaw at Bedlington Ironworks, Morpeth. These were longer than cast-iron rails and were not brittle: they made a track well suited for locomotives. In June 1823 George and Robert Stephenson, with other partners, founded a firm in Newcastle upon Tyne to build locomotives and rolling stock and to do general engineering work: after its Managing Partner, the firm was called Robert Stephenson \& Co.

In 1824 the promoters of the Liverpool \& Manchester Railway (L \& MR) invited George Stephenson to resurvey their proposed line in order to reduce opposition to it. William James, a wealthy land agent who had become a visionary protagonist of a national railway network and had seen Stephenson's locomotives at Killingworth, had promoted the L \& MR with some merchants of Liverpool and had carried out the first survey; however, he overreached himself in business and, shortly after the invitation to Stephenson, became bankrupt. In his own survey, however, George Stephenson lacked the assistance of his son Robert, who had left for South America, and he delegated much of the detailed work to incompetent assistants. During a devastating Parliamentary examination in the spring of 1825, much of his survey was shown to be seriously inaccurate and the L \& MR's application for an Act of Parliament was refused. The railway's promoters discharged Stephenson and had their line surveyed yet again, by C.B. Vignoles.

The Stockton \& Darlington Railway was, however, triumphantly opened in the presence of vast crowds in September 1825, with Stephenson himself driving the locomotive Locomotion, which had been built at Robert Stephenson \& Co.'s Newcastle works. Once the railway was at work, horse-drawn and gravity-powered traffic shared the line with locomotives: in 1828 Stephenson invented the horse dandy, a wagon at the back of a train in which a horse could travel over the gravity-operated stretches, instead of trotting behind.

Meanwhile, in May 1826, the Liverpool \& Manchester Railway had successfully obtained its Act of Parliament. Stephenson was appointed Engineer in June, and since he and Vignoles proved incompatible the latter left early in 1827. The railway was built by Stephenson and his staff, using direct labour. A considerable controversy arose c. 1828 over the motive power to be used: the traffic anticipated was too great for horses, but the performance of the reciprocal system of cable haulage developed by Benjamin Thompson appeared in many respects superior to that of contemporary locomotives. The company instituted a prize competition for a better locomotive and the Rainhill Trials were held in October 1829.

Robert Stephenson had been working on improved locomotive designs since his return from America in 1827, but it was the L \& MR's Treasurer, Henry Booth, who suggested the multi-tubular boiler to George Stephenson. This was incorporated into a locomotive built by Robert Stephenson for the trials: Rocket was entered by the three men in partnership. The other principal entrants were Novelty, entered by John Braithwaite and John Ericsson, and Sans Pareil, entered by Timothy Hackworth, but only Rocket, driven by George Stephenson, met all the organizers' demands; indeed, it far surpassed them and demonstrated the practicability of the long-distance steam railway. With the opening of the Liverpool \& Manchester Railway in 1830, the age of railways began.

Stephenson was active in many aspects. He advised on the construction of the Belgian State Railway, of which the Brussels-Malines section, opened in 1835, was the first all-steam railway on the European continent. In England, proposals to link the L \& MR with the Midlands had culminated in an Act of Parliament for the Grand Junction Railway in 1833: this was to run from Warrington, which was already linked to the L \& MR, to Birmingham. George Stephenson had been in charge of the surveys, and for the railway's construction he and J.U. Rastrick were initially Principal Engineers, with Stephenson's former pupil Joseph Locke under them; by 1835 both Stephenson and Rastrick had withdrawn and Locke was Engineer-in-Chief. Stephenson remained much in demand elsewhere: he was particularly associated with the construction of the North Midland Railway (Derby to Leeds) and related lines. He was active in many other places and carried out, for instance, preliminary surveys for the Chester \& Holyhead and Newcastle \& Berwick Railways, which were important links in the lines of communication between London and, respectively, Dublin and Edinburgh.

He eventually retired to Tapton House, Chesterfield, overlooking the North Midland. A man who was self-made (with great success) against colossal odds, he was ever reluctant, regrettably, to give others their due credit, although in retirement, immensely wealthy and full of honour, he was still able to mingle with people of all ranks.

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SUBJECT AREA: Ports and shipping

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The first thirty years of Tideman's life followed the normal pattern for a naval architect: study at the Breda Military Academy, work in the Royal Dockyards of Vlissingen as a constructor and then experience in the United Kingdom "standing by" an armoured vessel being built for the Dutch at Birkenhead. Tideman took the opportunity to acquaint himself with current developments in British shipyards and to study the work of Macquorn Rankine at Glasgow University.

On his return to the Netherlands he was given the task of adapting the Royal Dockyard of Amsterdam for ironclad construction and from 1870 iron ships were built there. From 1868 until 1873 he taught shipbuilding at what was then the Delft Polytechnic, but resigned on his appointment as Chief Naval Constructor of Holland.

Through representations to appropriate authority he assisted in founding the great shipyard Koninklijke Maatschappij "De Schelde" and in the setting up of Dutch ferry services across the North Sea. His interest in ship design and in the pioneering work of William Froude led to the founding of the world's second ship model test tank in 1876 in a sheltered part of the Royal Amsterdam Dockyard. The design was based on Froude's Torquay Tank.

As Scotland's first tank was not opened until 1883, he attracted work from the Clyde, including the testing of the Russian Imperial Yacht Livadia built by Elder's of Glasgow. This contract was so critical that it was agreed that a quartersize model be tested on Loch Lomond. Throughout his life he was respected as an all-round engineer and consultancy work flowed in, the vast bulk of it from Britain. Continual trying to improve standards, Tideman was working on a development plan for Dutch shipbuilding at the time of his death.

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access variable вчт. переменная доступа anonymous variable вчт. анонимная переменная apparent variable вчт. связанная переменная array variable вчт. массив attitude variable показатель отношения потребителей automatic variable вчт. динамическая локальная переменная autonomous variable вчт. независимая переменная auxiliary variable вчт. вспомогательная переменная background variable основная переменная based variable вчт. базированная переменная basic variable вчт. базисная переменная boolean variable вчт. логическая переменная bound variable вчт. связанная переменная bounded variable вчт. ограниченная переменная chance variable случайная величина chance variable вчт. случайная переменная character variable вчт. знаковая переменная class variable вчт. переменная класса compile-time variable вчт. переменная периода трансляции complemented variable вчт. переменная с отрицанием continuous variable вчт. непрерывная переменная control variable вчт. управляющая переменная correlated variables коррелированные переменные critical variable стат. критический фактор discontinuous variable вчт. разрывная переменная discrete variable вчт. дискретная переменная dual variable вчт. двойственная переменная dummy variable вчт. несущественная переменная dummy variable вчт. фиктивная переменная environment variable вчт. переменная режима file variable вчт. файловая переменная fixed variable вчт. заданная переменная free variable вчт. свободная переменная global variable вчт. глобальная переменная hidden variable вчт. замаскированная переменная independent variable вчт. независимая переменная independent variable независимая переменная independent variable стат. независимая переменная instance variable вчт. экземплярная переменная integer variable вчт. целая переменная integer variable вчт. целочисленная переменная jointly dependent variables вчт. совместно зависимые переменные label variable вчт. переменная типа метки latent variable вчт. ненаблюдаемая переменная latent variable вчт. скрытая переменная leading variable вчт. ведущая переменная legitimate variable вчт. истинная переменная linguistic variable вчт. лингвистическая переменная loop variable вчт. параметр из цикла master variable вчт. главная переменная memory variable вчт. переменная памяти metalinguistic variable вчт. металингвистическая переменная missing variable вчт. недостающая переменная monetary variable денежная переменная величина monetary variable денежный фактор morphic variable вчт. морфическая переменная multiple random variable многомерная случайная величина nonbasic variable вчт. небазисная переменная nonrandom variable вчт. неслучайная переменная normalized variable вчт. нормированная переменная numerical variable вчт. числовая переменная operation variable вчт. операторная переменная outgoing variable вчт. выводимая переменная output variable вчт. выходная переменная predetermined variable вчт. заранее определенная переменная primal variable переменная прямой задачи primal variables переменные прямой задачи queue-size variable вчт. длина очереди random variable случайная величина real variable вчт. вещественная переменная register variable вчт. регистровая переменная service-time variable вчт. время обслуживания slack variable вчт. свободная переменная slave variable вчт. зависимая переменная state variable вчт. переменная состояния state variable вчт. фазовая переменная status variable вчт. параметр состояния stochastic variable вчт. случайная величина stochastic variables случайные величины stochastical variable вчт. случайная величина stochastical variables случайные величины string variable вчт. строковая переменная subscript variable вчт. индексированная переменная syntactic variable вчт. синтаксическая переменная system variable вчт. системная переменная task variable вчт. переменная задачи temporary variable вчт. временная переменная unbound variable вчт. несвязанная переменная uncomplemented variable вчт. переменная без отрицания undeclared variable вчт. необъявленная переменная uninitialized variable вчт. неинициализированная переменная unrestricted variable вчт. не имеющая ограничений переменная unrestricted variable вчт. неограниченная переменная variable биол. аберрантный; изменчивый variable изменчивый, непостоянный; variable weather неустойчивая погода variable изменчивый variable изменяемый variable количественный признак variable меняющийся variable непостоянный variable мор. неровный ветер variable неустойчивый variable вчт. переменная variable мат. переменная (величина) variable мат. переменная величина variable переменный (тж. мат.) variable переменный variable регулируемый variable мор. районы океана, где нет постоянного ветра variable изменчивый, непостоянный; variable weather неустойчивая погода word variable вчт. переменная типа слово