development+study

SUBJECT AREA: Metallurgy

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After graduating in chemistry from the Ecole Polytechnique in 1887, Charpy continued to work there on the physical chemistry of solutions for his doctorate. He joined the Laboratoire d'Artillerie de la Marine in 1892 and began to study the structure and mechanical properties of various steels in relation to their previous heat treatment. His first memoir, on the mechanical properties of steels quenched from various temperatures, was published in 1892 on the advice of Henri Le Chatelier. He joined the Compagnie de Chatillon Commentry Fourchamboult et Decazeville at their steelworks in Imphy in 1898, shortly after the discovery of Invar by G.E. Guillaume. Most of the alloys required for this investigation had been prepared at Imphy, and their laboratories were therefore well equipped with sensitive and refined dilatometric facilities. Charpy and his colleague L.Grenet utilized this technique in many of their earlier investigations, which were largely concerned with the transformation points of steel. He began to study the magnetic characteristics of silicon steels in 1902, shortly after their use as transformer laminations had first been proposed by Hadfield and his colleagues in 1900. Charpy was the first to show that the magnetic hysteresis of these alloys decreased rapidly as their grain size increased.

The first details of Charpy's pendulum impact testing machine were published in 1901, about two years before Izod read his paper to the British Association. As with Izod's machine, the energy of fracture was measured by the retardation of the pendulum. Charpy's test pieces, however, unlike those of Izod, were in the form of centrally notched beams, freely supported at each end against rigid anvils. This arrangement, it was believed, transmitted less energy to the frame of the machine and allowed the energy of fracture to be more accurately measured. In practice, however, the blow of the pendulum in the Charpy test caused visible distortion in the specimen as a whole. Both tests were still widely used in the 1990s.

In 1920 Charpy left Imphy to become Director-General of the Compagnie des Aciéries de la Marine et Homecourt. After his election to the Académie des Sciences in 1918, he came to be associated with Floris Osmond and Henri Le Chatelier as one of the founders of the "French School of Physical Metallurgy". Around the turn of the century he had contributed much to the development of the metallurgical microscope and had helped to introduce the Chatelier thermocouple into the laboratory and to industry. He also popularized the use of platinum-wound resistance furnaces for laboratory purposes. After 1920 his industrial responsibilities increased greatly, although he continued to devote much of his time to teaching at the Ecole Supérieure des Mines in Paris, and at the Ecole Polytechnique. His first book, Leçons de Chimie (1892, Paris), was written at the beginning of his career, in association with H.Gautier. His last, Notions élémentaires de sidérurgie (1946, Paris), with P.Pingault as co-author, was published posthumously.

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SUBJECT AREA: Metallurgy

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Of New England ancestry, his family returned there soon after his birth and later moved to Cleveland, Ohio. In 1884, Dow entered the Case School of Applied Science, graduating in science four years later. His thesis dealt partly with the brines of Ohio, and he was persuaded to present a paper on brine to the meeting of the American Association for he Advancement of Science being held in Cleveland the same year. That entailed visits to collect samples of brines from various localities, and led to the observation that their composition varied, one having a higher lithium content while another was richer in bromine. This study of brines proved to be the basis for his career in industrial chemistry. In 1888 Dow was appointed Professor of Chemistry at the Homeopathic Hospital College in Cleveland, but he continued to work on brine, obtaining a patent in the same year for extracting bromine by blowing air through slightly electrolysed brine. He set up a small company to exploit the process, but it failed; the process was taken up and successfully worked by the Midland Chemical Company in Midland, Michigan. The electrolysis required a direct-current generator which, when it was installed in 1892, was probably the first of its kind in America. Dow next set up a company to produce chlorine by the electrolysis of brine. It moved to Midland in 1896, and the Dow Central Company purchased the Midland Chemical Company in 1900. Its main concern was the manufacture of bleaching powder, but the company continued to grow, based on Dow's steady development of chemical compounds that could be derived from brines. His search for further applications of chlorine led to the making of insecticides and an interest in horticulture. Meanwhile, his experience at the Homeopathic Hospital doubtless fired an interest in pharmaceuticals. One of the substances found in brine was magnesium chloride, and by 1918 magnesium metal was being produced on a small scale by electrolysis. An intensive study of its alloys followed, leading to the large-scale production of these important light-metal alloys, under the name of Dowmetals. Two other "firsts" achieved by the company were the synthetic indigo process and the production of the element iodine in the USA. The Dow company became one of the leading chemical manufacturers in the USA, and at the same time Dow played an active part in public life, serving on many public and education boards.

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SUBJECT AREA: Medical technology

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Of Quaker stock, his father also being a Fellow of the Royal Society, he studied medicine at University College, London. He qualified, and became a Fellow of the Royal College of Surgeons, in 1852. Wishing to pursue a surgical career, he moved to Edinburgh to study surgery under William Syme, whose daughter he married in 1852, the same year he was appointed Assistant Surgeon to the Edinburgh Royal Infirmary.

Until his appointment as Regius Professor of Surgery at Glasgow University and Glasgow Royal Infirmary in 1861, he was engaged in a wide variety of investigations into the nature of inflammation and the effects of irritants on wounds. Following his move to Glasgow, he became particularly involved in the major problems arising out of the vast increase in the number of surgical procedures brought about by the recent introduction of general anaesthesia. By 1865 his continuing study of wound inflammation and the microbial studies of Pasteur had led him to institute in the operating theatre a regime of surgical antisepsis involving the use of a carbolic acid spray coupled with the sterilization of instruments, the site of operation and the hands of the operator. Increasingly it was appreciated that the air was the least important origin of infection, and by 1887 the antiseptic approach had been superseded by the aseptic.

In 1869 he succeeded Syme in the Chair at Edinburgh and his methods were widely accepted abroad. In 1877 he moved to the Chair of Surgery at King's College Hospital, London, in the hope of encouraging acceptance of his work in the metropolis. As well as developing a variety of new surgical procedures, he was engaged for many years in the development of surgical ligatures, which had always been a potent stimulant of infection. His choice of catgut as a sterilizable, absorbable material paved the way for major developments in this field. The Lister Institute of Preventive Medicine was named in his honour in 1903.

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SUBJECT AREA: Chemical technology, Electricity

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Maxwell attended school at the Edinburgh Academy and at the age of 16 went on to study at Edinburgh University. In 1850 he entered Trinity College, Cambridge, where he graduated four years later as Second Wrangler with the award of the Smith's Prize. Two years later he was appointed Professor at Marischal College, Aberdeen, where he married the Principal's daughter. In 1860 he moved to King's College London, but on the death of his father five years later, Maxwell returned to the family home in Scotland, where he continued his researches as far as the life of a gentleman farmer allowed. This rural existence was interrupted in 1874 when he was persuaded to accept the chair of Cavendish Professor of Experimental Physics at Cambridge. Unfortunately, in 1879 he contracted the cancer that brought his brilliant career to an untimely end. While at Cambridge, Maxwell founded the Cavendish Laboratory for research in physics. A succession of distinguished physicists headed the laboratory, making it one of the world's great centres for notable discoveries in physics.

During the mid-1850s, Maxwell worked towards a theory to explain electrical and magnetic phenomena in mathematical terms, culminating in 1864 with the formulation of the fundamental equations of electromagnetism (Maxwell's equations). These equations also described the propagation of light, for he had shown that light consists of transverse electromagnetic waves in a hypothetical medium, the "ether". This great synthesis of theories uniting a wide range of phenomena is worthy to set beside those of Sir Isaac Newton and Einstein. Like all such syntheses, it led on to further discoveries. Maxwell himself had suggested that light represented only a small part of the spectrum of electromagnetic waves, and in 1888 Hertz confirmed the discovery of another small part of the spectrum, radio waves, with momentous implications for the development of telecommunication technology. Maxwell contributed to the kinetic theory of gases, which by then were viewed as consisting of a mass of randomly moving molecules colliding with each other and with the walls of the containing vessel. From 1869 Maxwell applied statistical methods to describe the molecular motion in mathematical terms. This led to a greater understanding of the behaviour of gases, with important consequences for the chemical industry.

Of more direct technological application was Maxwell's work on colour vision, begun in 1849, showing that all colours could be derived from the three primary colours, red, yellow and blue. This enabled him in 1861 to produce the first colour photograph, of a tartan. Maxwell's discoveries about colour vision were quickly taken up and led to the development of colour printing and photography.

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SUBJECT AREA: Agricultural and food technology, Chemical technology

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Sustained by the family tanning business in Dole, near the Swiss border, Pasteur's school career was undistinguished, sufficing to gain him entry into the teacher-training college in Paris, the Ecole Normale, There the chemical lectures by the great organic chemist J.B.A.Dumas (1800–84) fired Pasteur's enthusiasm for chemistry which never left him. Pasteur's first research, carried out at the Ecole, was into tartaric acid and resulted in the discovery of its two optically active forms resulting from dissymmetrical forms of their molecules. This led to the development of stereochemistry. Next, an interest in alcoholic fermentation, first as Professor of Chemistry at Lille University in 1854 and then back at the Ecole from 1857, led him to deny the possibility of spontaneous generation of animal life. Doubt had previously been cast on this, but it was Pasteur's classic research that finally established that the putrefaction of broth or the fermentation of sugar could not occur spontaneously in sterile conditions, and could only be caused by airborne micro-organisms. As a result, he introduced pasteurization or brief, moderate heating to kill pathogens in milk, wine and other foods. The suppuration of wounds was regarded as a similar process, leading Lister to apply Pasteur's principles to revolutionize surgery. In 1860, Pasteur himself decided to turn to medical research. His first study again had important industrial implications, for the silk industry was badly affected by diseases of the silkworm. After prolonged and careful investigation, Pasteur found ways of dealing with the two main infections. In 1868, however, he had a stroke, which prevented him from active carrying out experimentation and restricted him to directing research, which actually was more congenial to him. Success with disease in larger animals came slowly. In 1879 he observed that a chicken treated with a weakened culture of chicken-cholera bacillus would not develop symptoms of the disease when treated with an active culture. He compared this result with Jenner's vaccination against smallpox and decided to search for a vaccine against the cattle disease anthrax. In May 1881 he staged a demonstration which clearly showed the success of his new vaccine. Pasteur's next success, finding a vaccine which could protect against and treat rabies, made him world famous, especially after a person was cured in 1885. In recognition of his work, the Pasteur Institute was set up in Paris by public subscription and opened in 1888. Pasteur's genius transcended the boundaries between science, medicine and technology, and his achievements have had significant consequences for all three fields.

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SUBJECT AREA: Broadcasting, Electronics and information technology, Recording, Telecommunications

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From an early age he was absorbed by phenomena of physics to the exclusion of all other subjects, including mathematics. When choosing his subjects for the final three years in Borgedydskolen in Christianshavn (Copenhagen) before university, he opted for languages and history. At the University of Copenhagen he embarked on the study of medicine in 1889, but broke it off and was apprenticed to the machine firm of A/S Frichs Eftf. in Aarhus. He was employed between 1893 and 1899 as a mechanic and assistant in the laboratory of the Copenhagen Telephone Company KTAS. Eventually he advanced to be Head of the line fault department. This suited his desire for experiment and measurement perfectly. After the invention of the telegraphone in 1898, he left the laboratory and with responsible business people he created Aktieselskabet Telegrafonen, Patent Poulsen in order to develop it further, together with Peder Oluf Pedersen (1874– 1941). Pedersen brought with him the mathematical background which eventually led to his professorship in electronic engineering in 1922.

The telegraphone was the basis for multinational industrial endeavours after it was demonstrated at the 1900 World's Exhibition in Paris. It must be said that its strength was also its weakness, because the telegraphone was unique in bringing sound recording and reproduction to the telephone field, but the lack of electronic amplifiers delayed its use outside this and the dictation fields (where headphones could be used) until the 1920s. However, commercial interest was great enough to provoke a number of court cases concerning patent infringement, in which Poulsen frequently figured as a witness.

In 1903–4 Poulsen and Pedersen developed the arc generator for continuous radio waves which was used worldwide for radio transmitters in competition with Marconi's spark-generating system. The inspiration for this work came from the research by William Duddell on the musical arc. Whereas Duddell had proposed the use of the oscillations generated in his electric arc for telegraphy in his 1901 UK patent, Poulsen contributed a chamber of hydrogen and a transverse magnetic field which increased the efficiency remarkably. He filed patent applications on these constructions from 1902 and the first publication in a scientific forum took place at the International Electrical Congress in St Louis, Missouri, in 1904.

In order to use continuous waves efficiently (the high frequency constituted a carrier), Poulsen developed both a modulator for telegraphy and a detector for the carrier wave. The modulator was such that even the more primitive spark-communication receivers could be used. Later Poulsen and Pedersen developed frequency-shift keying.

The Amalgamated Radio-Telegraph Company Ltd was launched in London in 1906, combining the developments of Poulsen and those of De Forest Wireless Telegraph Syndicate. Poulsen contributed his English and American patents. When this company was liquidated in 1908, its assets were taken over by Det Kontinentale Syndikat for Poulsen Radio Telegrafi, A/S in Copenhagen (liquidated 1930–1). Some of the patents had been sold to C.Lorenz AG in Berlin, which was very active.

The arc transmitting system was in use worldwide from about 1910 to 1925, and the power increased from 12 kW to 1,000 kW. In 1921 an exceptional transmitter rated at 1,800 kW was erected on Java for communications with the Netherlands. More than one thousand installations had been in use worldwide. The competing systems were initially spark transmitters (Marconi) and later rotary converters ( Westinghouse). Similar power was available from valve transmitters only much later.

From c. 1912 Poulsen did not contribute actively to further development. He led a life as a well-respected engineer and scientist and served on several committees. He had his private laboratory and made experiments in the composition of matter and certain resonance phenomena; however, nothing was published. It has recently been suggested that Poulsen could not have been unaware of Oberlin Smith's work and publication in 1888, but his extreme honesty in technical matters indicates that his development was indeed independent. In the case of the arc generator, Poulsen was always extremely frank about the inspiration he gained from earlier developers' work.

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SUBJECT AREA: Electronics and information technology, Telecommunications

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As a child, Shannon tinkered with radio kits and enjoyed solving puzzles, particularly crypto-graphic ones. He graduated from the University of Michigan in 1936 with a Bachelor of Science in mathematics and electrical engineering, and earned his Master's degree from the Massachusetts Institute of Technology (MIT) in 1937. His thesis on applying Boolean algebra to switching circuits has since been acclaimed as possibly the most significant this century. Shannon earned his PhD in mathematics from MIT in 1940 with a dissertation on the mathematics of genetic transmission.

Shannon spent a year at the Institute for Advanced Study in Princeton, then in 1941 joined Bell Telephone Laboratories, where he began studying the relative efficiency of alternative transmission systems. Work on digital encryption systems during the Second World War led him to think that just as ciphers hide information from the enemy, "encoding" information could also protect it from noise. About 1948, he decided that the amount of information was best expressed quantitatively in a two-value number system, using only the digits 0 and 1. John Tukey, a Princeton colleague, named these units "binary digits" (or, for short, "bits"). Almost all digital computers and communications systems use such on-off, or two-state logic as their basis of operation.

Also in the 1940s, building on the work of H. Nyquist and R.V.L. Hartley, Shannon proved that there was an upper limit to the amount of information that could be transmitted through a communications channel in a unit of time, which could be approached but never reached because real transmissions are subject to interference (noise). This was the beginning of information theory, which has been used by others in attempts to quantify many sciences and technologies, as well as subjects in the humanities, but with mixed results. Before 1970, when integrated circuits were developed, Shannon's theory was not the preferred circuit-and-transmission design tool it has since become.

Shannon was also a pioneer in the field of artificial intelligence, claiming that computing machines could be used to manipulate symbols as well as do calculations. His 1953 paper on computers and automata proposed that digital computers were capable of tasks then thought exclusively the province of living organisms. In 1956 he left Bell Laboratories to join the MIT faculty as Professor of Communications Science.

On the lighter side, Shannon has built many devices that play games, and in particular has made a scientific study of juggling.

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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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