engineer's method

1) Oil: wait and weight (метод управления скважиной в случае опасности выброса, при котором циркуляция прекращается до приготовления бурового раствора необходимой плотности)

2) oil&gas: engineer's method, wait-and-weight method

SUBJECT AREA: Metallurgy

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Brinell graduated as an engineer from Boräs Technical School, and his interest in metallurgy began to develop in 1875 when he became an engineer at the ironworks of Lesjöfors and came under the influence of Gustaf Ekman. In 1882 he was appointed Chief Engineer at the Fagersta Ironworks, where he became one of Sweden's leading experts in the manufacture and heat treatment of tool steels.

His reputation in this field was established in 1885 when he published a paper on the structural changes which occurred in steels when they were heated and cooled, and he was among the first to recognize and define the critical points of steel and their importance in heat treatment. Some of these preliminary findings were first exhibited at Stockholm in 1897. His exhibit at the World Exhibition at Paris in 1900 was far more detailed and there he displayed for the first time his method of hardness determination using a steel-ball indenter. For these contributions he was awarded the French Grand Prix and also the Polhem Prize of the Swedish Technical Society.

He was later concerned with evaluating and developing the iron-ore deposits of north Sweden and was one of the pioneers of the electric blast-furnace. In 1903 he became Chief Engineer of the Jernkontoret and remained there until 1914. In this capacity and as Editor of the Jernkontorets Annaler he made significant contributions to Swedish metallurgy. His pioneer work on abrasion resistance, undertaken long before the term tribology had been invented, gained him the Rinman Medal, awarded by the Jernkontoret in 1920.

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SUBJECT AREA: Civil engineering, Mining and extraction technology

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Greathead came to England in 1859 to complete his education. In 1864 he began a three-year pupillage with the civil engineer Peter W. Barlow, after which he was engaged as an assistant engineer on the extension of the Midland Railway from Bedford to London. In 1869 he was entrusted with the construction of the Tower Subway under the River Thames; this was carried out using a cylindrical wrought-iron shield which was forced forward by six large screws as material was excavated in front of it. This work was completed the same year. In 1870 he set himself up as a consulting engineer, and from 1873 he was Resident Engineer on the Hammersmith and Richmond extensions of the Metropolitan District Railway. He assisted in the preparation of several other railway projects including the Regent's Canal Railway in 1880, the Dagenham Dock and the Metropolitan Outer Circle Railways in 1881, a new line from London to Eastbourne and a number of Irish light railways. He worked on a bill for the City and South London Railway, which was built between 1886 and 1890; here compressed air was used to prevent the inrush of water, a method for tunnelling which was generally adopted from then on. He invented apparatus for the application of water to excavate in front of the shield as well as for injecting cement-grout behind the lining of the tunnel.

He was joint engineer with Sir Douglas Fox for the construction of the Liverpool Overhead Railway, and held the same post with W.R.Galbraith on the Waterloo and City Railway; he was also associated with Sir John Fowler and Sir Benjamin Baker in the construction of the Central London Railway. He died, aged 52, before the completion of some of these projects.

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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: Land transport, Railways and locomotives

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Robert Stephenson's father was George Stephenson, who ensured that his son was educated to obtain the theoretical knowledge he lacked himself. In 1821 Robert Stephenson assisted his father in his survey of the Stockton \& Darlington Railway and in 1822 he assisted William James in the first survey of the Liverpool \& Manchester Railway. He then went to Edinburgh University for six months, and the following year Robert Stephenson \& Co. was named after him as Managing Partner when it was formed by himself, his father and others. The firm was to build stationary engines, locomotives and railway rolling stock; in its early years it also built paper-making machinery and did general engineering.

In 1824, however, Robert Stephenson accepted, perhaps in reaction to an excess of parental control, an invitation by a group of London speculators called the Colombian Mining Association to lead an expedition to South America to use steam power to reopen gold and silver mines. He subsequently visited North America before returning to England in 1827 to rejoin his father as an equal and again take charge of Robert Stephenson \& Co. There he set about altering the design of steam locomotives to improve both their riding and their steam-generating capacity. Lancashire Witch, completed in July 1828, was the first locomotive mounted on steel springs and had twin furnace tubes through the boiler to produce a large heating surface. Later that year Robert Stephenson \& Co. supplied the Stockton \& Darlington Railway with a wagon, mounted for the first time on springs and with outside bearings. It was to be the prototype of the standard British railway wagon. Between April and September 1829 Robert Stephenson built, not without difficulty, a multi-tubular boiler, as suggested by Henry Booth to George Stephenson, and incorporated it into the locomotive Rocket which the three men entered in the Liverpool \& Manchester Railway's Rainhill Trials in October. Rocket, was outstandingly successful and demonstrated that the long-distance steam railway was practicable.

Robert Stephenson continued to develop the locomotive. Northumbrian, built in 1830, had for the first time, a smokebox at the front of the boiler and also the firebox built integrally with the rear of the boiler. Then in Planet, built later the same year, he adopted a layout for the working parts used earlier by steam road-coach pioneer Goldsworthy Gurney, placing the cylinders, for the first time, in a nearly horizontal position beneath the smokebox, with the connecting rods driving a cranked axle. He had evolved the definitive form for the steam locomotive.

Also in 1830, Robert Stephenson surveyed the London \& Birmingham Railway, which was authorized by Act of Parliament in 1833. Stephenson became Engineer for construction of the 112-mile (180 km) railway, probably at that date the greatest task ever undertaken in of civil engineering. In this he was greatly assisted by G.P.Bidder, who as a child prodigy had been known as "The Calculating Boy", and the two men were to be associated in many subsequent projects. On the London \& Birmingham Railway there were long and deep cuttings to be excavated and difficult tunnels to be bored, notoriously at Kilsby. The line was opened in 1838.

In 1837 Stephenson provided facilities for W.F. Cooke to make an experimental electrictelegraph installation at London Euston. The directors of the London \& Birmingham Railway company, however, did not accept his recommendation that they should adopt the electric telegraph and it was left to I.K. Brunel to instigate the first permanent installation, alongside the Great Western Railway. After Cooke formed the Electric Telegraph Company, Stephenson became a shareholder and was Chairman during 1857–8.

Earlier, in the 1830s, Robert Stephenson assisted his father in advising on railways in Belgium and came to be increasingly in demand as a consultant. In 1840, however, he was almost ruined financially as a result of the collapse of the Stanhope \& Tyne Rail Road; in return for acting as Engineer-in-Chief he had unwisely accepted shares, with unlimited liability, instead of a fee.

During the late 1840s Stephenson's greatest achievements were the design and construction of four great bridges, as part of railways for which he was responsible. The High Level Bridge over the Tyne at Newcastle and the Royal Border Bridge over the Tweed at Berwick were the links needed to complete the East Coast Route from London to Scotland. For the Chester \& Holyhead Railway to cross the Menai Strait, a bridge with spans as long-as 460 ft (140 m) was needed: Stephenson designed them as wrought-iron tubes of rectangular cross-section, through which the trains would pass, and eventually joined the spans together into a tube 1,511 ft (460 m) long from shore to shore. Extensive testing was done beforehand by shipbuilder William Fairbairn to prove the method, and as a preliminary it was first used for a 400 ft (122 m) span bridge at Conway.

In 1847 Robert Stephenson was elected MP for Whitby, a position he held until his death, and he was one of the exhibition commissioners for the Great Exhibition of 1851. In the early 1850s he was Engineer-in-Chief for the Norwegian Trunk Railway, the first railway in Norway, and he also built the Alexandria \& Cairo Railway, the first railway in Africa. This included two tubular bridges with the railway running on top of the tubes. The railway was extended to Suez in 1858 and for several years provided a link in the route from Britain to India, until superseded by the Suez Canal, which Stephenson had opposed in Parliament. The greatest of all his tubular bridges was the Victoria Bridge across the River St Lawrence at Montreal: after inspecting the site in 1852 he was appointed Engineer-in-Chief for the bridge, which was 1 1/2 miles (2 km) long and was designed in his London offices. Sadly he, like Brunel, died young from self-imposed overwork, before the bridge was completed in 1859.

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See also: Pihl, Carl Abraham; Seguin, Marc

SUBJECT AREA: Steam and internal combustion engines

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Jonathan came from a family with an engineering tradition: his grandfather Joseph had worked under Thomas Newcomen. Jonathan was the sixth child in a family of thirteen whose names all began with "J". In 1781 he was living at Penryn, Cornwall and described himself as a plumber, brazier and engineer. As early as 1776, when he wished to amuse himself by making a small st-eam engine, he wanted to make something new and wondered if the steam would perform more than one operation in an engine. This was the foundation for his compound engine. He worked on engines in Cornwall, and in 1778 was Engineer at the Ting Tang mine where he helped Boulton \& Watt erect one of their engines. He was granted a patent in 1781 and in that year tried a large-scale experiment by connecting together two engines at Wheal Maid. Very soon John Winwood, a partner in a firm of iron founders at Bristol, acquired a share in the patent, and in 1782 an engine was erected in a colliery at Radstock, Somerset. This was probably not very successful, but a second was erected in the same area. Hornblower claimed greater economy from his engines, but steam pressures at that time were not high enough to produce really efficient compound engines. Between 1790 and 1794 ten engines with his two-cylinder arrangement were erected in Cornwall, and this threatened Boulton \& Watt's near monopoly. At first the steam was condensed by a surface condenser in the bottom of the second, larger cylinder, but this did not prove very successful and later a water jet was used. Although Boulton \& Watt proceeded against the owners of these engines for infringement of their patent, they did not take Jonathan Hornblower to court. He tried a method of packing the piston rod by a steam gland in 1781 and his work as an engineer must have been quite successful, for he left a considerable fortune on his death.

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SUBJECT AREA: Electricity, Public utilities

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Ferranti, who had taken an interest in electrical and mechanical devices from an early age, was educated at St Augustine's College in Ramsgate and for a short time attended evening classes at University College, London. Rather than pursue an academic career, Ferranti, who had intense practical interests, found employment in 1881 with the Siemens Company (see Werner von Siemens) in their experimental department. There he had the opportunity to superintend the installation of electric-lighting plants in various parts of the country. Becoming acquainted with Alfred Thomson, an engineer, Ferranti entered into a short-lived partnership with him to manufacture the Ferranti alternator. This generator, with a unique zig-zag armature, had an efficiency exceeding that of all its rivals. Finding that Sir William Thomson had invented a similar machine, Ferranti formed a company with him to combine the inventions and produce the Ferranti- Thomson machine. For this the Hammond Electric Light and Power Company obtained the sole selling rights.

In 1885 the Grosvenor Gallery Electricity Supply Corporation was having serious problems with its Gaulard and Gibbs series distribution system. Ferranti, when consulted, reviewed the design and recommended transformers connected across constant-potential mains. In the following year, at the age of 22, he was appointed Engineer to the company and introduced the pattern of electricity supply that was eventually adopted universally. Ambitious plans by Ferranti for London envisaged the location of a generating station of unprecedented size at Deptford, about eight miles (13 km) from the city, a departure from the previous practice of placing stations within the area to be supplied. For this venture the London Electricity Supply Corporation was formed. Ferranti's bold decision to bring the supply from Deptford at the hitherto unheard-of pressure of 10,000 volts required him to design suitable cables, transformers and generators. Ferranti planned generators with 10,000 hp (7,460 kW)engines, but these were abandoned at an advanced stage of construction. Financial difficulties were caused in part when a Board of Trade enquiry in 1889 reduced the area that the company was able to supply. In spite of this adverse situation the enterprise continued on a reduced scale. Leaving the London Electricity Supply Corporation in 1892, Ferranti again started his own business, manufacturing electrical plant. He conceived the use of wax-impregnated paper-insulated cables for high voltages, which formed a landmark in the history of cable development. This method of flexible-cable manufacture was used almost exclusively until synthetic materials became available. In 1892 Ferranti obtained a patent which set out the advantages to be gained by adopting sector-shaped conductors in multi-core cables. This was to be fundamental to the future design and development of such cables.

A total of 176 patents were taken out by S.Z. de Ferranti. His varied and numerous inventions included a successful mercury-motor energy meter and improvements to textile-yarn produc-tion. A transmission-line phenomenon where the open-circuit voltage at the receiving end of a long line is greater than the sending voltage was named the Ferranti Effect after him.

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SUBJECT AREA: Electricity, Electronics and information technology, Public utilities

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After attending Owens College, Manchester, Hopkinson was admitted to Trinity College, Cambridge, in 1867 to read for the Mathematical Tripos. An appointment in 1872 with the lighthouse department of the Chance Optical Works in Birmingham directed his attention to electrical engineering. His most noteworthy contribution to lighthouse engineering was an optical system to produce flashing lights that distinguished between individual beacons. His extensive researches on the dielectric properties of glass were recognized when he was elected to a Fellowship of the Royal Society at the age of 29. Moving to London in 1877 he became established as a consulting engineer at a time when electricity supply was about to begin on a commercial scale. During the remainder of his life, Hopkinson's researches resulted in fundamental contributions to electrical engineering practice, dynamo design and alternating current machine theory. In making a critical study of the Edison dynamo he developed the principle of the magnetic circuit, a concept also arrived at by Gisbert Kapp around the same time. Hopkinson's improvement of the Edison dynamo by reducing the length of the field magnets almost doubled its output. In 1890, in addition to-his consulting practice, Hopkinson accepted a post as the first Professor of Electrical Engineering and Head of the Siemens laboratory recently established at King's College, London. Although he was not involved in lecturing, the position gave him the necessary facilities and staff and student assistance to continue his researches. Hopkinson was consulted on many proposals for electric traction and electricity supply, including schemes in London, Manchester, Liverpool and Leeds. He also advised Mather and Platt when they were acting as contractors for the locomotives and generating plant for the City and South London tube railway. As early as 1882 he considered that an ideal method of charging for the supply of electricity should be based on a two-part tariff, with a charge related to maximum demand together with a charge for energy supplied. Hopkinson was one the foremost expert witnesses of his day in patent actions and was himself the patentee of over forty inventions, of which the three-wire system of distribution and the series-parallel connection of traction motors were his most successful. Jointly with his brother Edward, John Hopkinson communicated the outcome of his investigations to the Royal Society in a paper entitled "Dynamo Electric Machinery" in 1886. In this he also described the later widely used "back to back" test for determining the characteristics of two identical machines. His interest in electrical machines led him to more fundamental research on magnetic materials, including the phenomenon of recalescence and the disappearance of magnetism at a well-defined temperature. For his work on the magnetic properties of iron, in 1890 he was awarded the Royal Society Royal Medal. He was a member of the Alpine Club and a pioneer of rock climbing in Britain; he died, together with three of his children, in a climbing accident.

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SUBJECT AREA: Mining and extraction technology

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A former Second Lieutenant of the Austrian navy (hence his later nickname "Captain") and graduate of the Polytechnic Institute of Graz, Lucas decided to stay in Michigan when he visited his relatives in 1879. He changed his original name, Lucie, into the form his uncle had adopted and became a naturalized American citizen at the age of 30. He worked in the lumber industry for some years and then became a consulting mechanical and mining engineer in Washington, DC. He began working for a salt-mining company in Louisiana in 1893 and became interested in the geology of the Mexican Gulf region, with a view to prospecting for petroleum. In the course of this work he came to the conclusion that the hills in this elevated area, being geological structures distinct from the surrounding deposits, were natural reservoirs of petroleum. To prove his unusual theory he subsequently chose Spindle Top, near Beaumont, Texas, where in 1899 he began to bore a first oil-well. A second drill-hole, started in October 1900, was put through clay and quicksand. After many difficulties, a layer of rock containing marine shells was reached. When the "gusher" came out on 10 January 1901, it not only opened up a new era in the oil and gas business, but it also led to the future exploration of the terrestrial crust.

Lucas's boring was a breakthrough for the rotary drilling system, which was still in its early days although its principles had been established by the English engineer Robert Beart in his patent of 1884. It proved to have advantages over the pile-driving of pipes. A pipe with a simple cutter at the lower end was driven with a constantly revolving motion, grinding down on the bottom of the well, thus gouging and chipping its way downward. To deal with the quicksand he adopted the use of large and heavy casings successively telescoped one into the other. According to Fauvelle's method, water was forced through the pipe by means of a pump, so the well was kept full of circulating liquid during drilling, flushing up the mud. When the salt-rock was reached, a diamond drill was used to test the depth and the character of the deposit.

When the well blew out and flowed freely he developed a preventer in order to save the oil and, even more importantly at the time, to shut the well and to control the oil flow. This assembly, patented in 1903, consisted of a combined system of pipes, valves and casings diverting the stream into a horizontal direction.

Lucas's fame spread around the world, but as he had to relinquish the larger part of his interest to the oil company supporting the exploration, his financial reward was poor. One year after his success at Spindle Top he started oil exploration in Mexico, where he stayed until 1905, when he resumed his consulting practice in Washington, DC.

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SUBJECT AREA: Broadcasting, Electronics and information technology

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In 1884, while still a student engineer, Nipkow patented a mechanical television pick-up device using a disc with a spiral of twenty-four holes rotating at 600 rpm in front of a selenium cell. He also proposed a display on an identical synchronous disc in conjunction with a light-modulator based on the Faraday effect. Unfortunately it was not possible to realize a working system at the time because of the slow response of selenium cells and the lack of suitable electronic-sig-nal amplifiers; he was unable to pay the extension fees and so the patent lapsed. Others took up the idea, however, and in 1907 pictures were sent between London and Paris by wire. Subsequently, the principle was used by Baird, Ives, and Jenkins.

For most of his working life after obtaining his doctorate, Nipkow was employed as an engineer by a company that made railway-signalling equipment, but his pioneering invention was finally recognized in 1934 when he was made Honorary President of the newly formed German Television Society.

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SUBJECT AREA: Paper and printing, Photography, film and optics

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Poitevin graduated as a chemical engineer from the Ecole Centrale in Paris in 1843. He was appointed as a chemist with the Salines National de l'Est, a post which allowed him time for research, and he soon became interested in the recent invention of photography. He conducted a series of electrolytic experiments on daguerreotype plates in 1847 and 1848 which led him to propose a method of photochemical engraving on plates coated with silver or gold. In 1850 he joined the firm of Periere in Lyons, and the same year travelled to Paris. During the 1850s, Poitevin conducted a series of far-reaching experiments on the reactions of chromates with light, and in 1855 he took out two important patents which exploited the light sensitivity of bichromated gelatine. Poitevin's work during this period is generally recognized as having established the essential principles of photolithography, carbon printing and collotype printing, key steps in the development of modern photomechanical printing. His contribution to the advancement of photography was widely recognized and honours were showered upon him. Particularly welcome was the greater part of the 10,000 franc prize awarded by the Duke of Lynes, a wealthy art lover, for the discovery of permanent photographic printing processes. This sum was not sufficient to allow Poitevin to stop working, however, and in 1869 he resumed his career as a chemical engineer, first managing a glass works and then travelling to Africa to work in silver mines. Upon the death of his father he returned to his home town, where he remained until his own death in 1882.

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SUBJECT AREA: Metallurgy

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Wöhler, the son of a schoolteacher, was born at Soltau on the Luneburg Heath and received his early education at his father's school, where his mathematical abilities soon became apparent. He completed his studies at the Technical High School, Hannover.

In 1840 he obtained a position at the Borsig Engineering Works in Berlin and acquired there much valuable experience in railway technology. He trained as an engine driver in Belgium and in 1843 was appointed as an engineer to the first Hannoverian Railway, then being constructed between Hannover and Lehrte. In 1847 he became Chief Superintendent of rolling stock on the Lower Silesian-Brandenhurg Railway, where his technical abilities influenced the Prussian Minister of Commerce to appoint him to a commission set up to investigate the reasons for the unusually high incidence of axle failures then being encountered on the railways. This was in 1852, and by 1854, when the Brandenburg line had been nationalized, Wöhler had already embarked on the long, systematic programme of mechanical testing which eventually provided him with a clear insight into the process of what is now referred to as "fatigue failure". He concentrated initially on the behaviour of machined iron and steel specimens subjected to fluctuating direct, bending and torsional stresses that were imposed by testing machines of his own design.

Although Wöhler was not the first investigator in this area, he was the first to recognize the state of "fatigue" induced in metals by the repeated application of cycles of stress at levels well below those that would cause immediate failure. His method of plotting the fatigue stress amplitude "S" against the number of stress cycles necessary to cause failure "N" yielded the well-known S-N curve which described very precisely the susceptibility to fatigue failure of the material concerned. Engineers were thus provided with an invaluable testing technique that is still widely used in the 1990s.

Between 1851 and 1898 Wöhler published forty-two papers in German technical journals, although the importance of his work was not initially fully appreciated in other countries. A display of some of his fracture fatigue specimens at the Paris Exposition in 1867, however, stimulated a short review of his work in Engineering in London. Four years later, in 1871, Engineering published a series of nine articles which described Wöhler's findings in considerable detail and brought them to the attention of engineers. Wöhler became a member of the newly created management board of the Imperial German Railways in 1874, an appointment that he retained until 1889. He is also remembered for his derivation in 1855 of a formula for calculating the deflections under load of lattice girders, plate girders, and other continuous beams resting on more than two supports. This "Three Moments" theorem appeared two years before Clapeyron independently advanced the same expression. Wöhler's other major contribution to bridge design was to use rollers at one end to allow for thermal expansion and contraction.

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SUBJECT AREA: Steam and internal combustion engines

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Renowned more for his ideas on technical matters than his practical deeds, Beau de Rochas was a prolific thinker. Within a few years he proposed a rail tunnel beneath the English Channel, a submarine telegraph, a new kind of drive for canal boats, the use of steel for high-pressure boilers and a method of improving the adhesion of locomotive wheels travelling the Alps.

The most notable of Beau de Rochas's ideas occurred in 1862 when he was employed as Ingenieur Attaché to the Central de Chemins. With remarkable foresight, he expressed the theoretical considerations for the cycle of operations for the now widely used four-stroke cycle engine. A French patent of 1862 lapsed with a failure to pay the annuity and thus the proposals for a new motive power lapsed into obscurity. Resurrected some twenty years later, the Beau de Rochas tract figures prominently in patent litigation cases. In 1885, a German court upheld a submission by a German patent lawyer that Otto's four-stroke engine of 1876 infringed the Beau de Rochas patent. It remains a mystery why Beau de Rochas never emerged at any time to defend his claims. In France he is regarded as the inventor of the four-stroke cycle engine.

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See also: Langen, Eugen

SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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Hugo Bilgram studied mechanical engineering at the Augsburg Maschinenbau Schule and graduated in 1865. He worked as a machinist and draughtsman for several firms in Germany before going to the United States in 1869.

In America he first worked for L.B.Flanders Company and Southwark Foundry \& Machine Company in Philadelphia, designing instruments and machines. In the 1870s he also assisted in an evening class in drawing at The Franklin Institute. He devised the Bilgram Valve Diagram for analysing the action of steam engine slide valves and he developed a method of drawing accurate outlines of gear teeth. This led him to design a machine for cutting the teeth of gear wheels, particularly bevel wheels, which he patented in 1884. He was in charge of the American branch of Brehmer Brothers Company from 1879 and in 1884 became the sole owner of the company, which was later incorporated as the Bilgram Machine Works. He was responsible for several other inventions and developments in gear manufacture.

Bilgram was a member of the Franklin Institute, the American Academy of Political and Social Science, the Philadelphia Technische Verein and the Philadelphia Engineer's Club, and was elected a member of the American Society of Mechanical Engineers in 1885. He was also an amateur botanist, keenly interested in microscopic work.

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SUBJECT AREA: Electricity, Public utilities, Railways and locomotives

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After attending the Technical College in Winterthur, Brown served with Emile Burgin in Basle before entering the Oerlikon engineering works near Zurich. Two years later he became Director of the electrical department of Oerlikon and from that time was involved in the development of electrical equipment for the generation and distribution of power. The Lauffen-Frankfurt 110-mile (177 km) transmission line of 1891 demonstrated the commercial feasibility of transmitting electrical power over great distances with three-phase alternating current. For this he designed a generator and early examples of oil-cooled transformers, and the scheme gave an impetus to the development of electric-power transmission throughout Europe. In 1891, in association with Walter Boveri, Brown founded the works of Brown Boveri \& Co. at Baden, Switzerland, and until his retirement in 1911 he devoted his energies to the design of polyphase alternating-current machinery. Important installations included the Frankfurt electricity works (1894), the Paderno-Milan transmission line, and the Lugano tramway of 1894, the first system in Europe to use three-phase traction motors. This tramway was followed by many other polyphase and mountain railways. The acquisition by Brown Boveri \& Co. in 1900 of the manufacturing rights of the Parsons steam turbine directed Brown's attention to problems associated with high-speed machines. Recognizing the high centrifugal stress involved, he began to employ solid cylindrical generator rotors with slots for the excitation winding, a method that has come to be universally adopted in large alternators.

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