complex+method

This method seems to be the least complex

This is the least useful of the above four theorems

   An anthropological and sociol ogical theory or complex of ideas allegedly showing a process of civilization relating to the significance of Portuguese activity in the tropics of Africa, Asia, and the Americas since 1415. As a theory and method of social science analysis, Luso-Tropicalism is a 20th-century phenomenon that has both academic and political (foreign and colonial policy) relevance. While the theory was based in part on French concepts of the "science of tropicology" in anthropology, it was Gilberto Freyre, an eminent Brazilian sociologist-anthropologist, who developed Luso-Tropicalism as an academic theory of the unique qualities of the Portuguese style of imperial activity in the tropics. In lectures, articles, and books during the period 1930-60, Freyre coined the term Luso-Tropicalism to describe Portuguese civilization in the tropics and to claim that the Portuguese, more than any other European colonizing people, successfully adapted their civilization to the tropics.

   From 1960 on, the academic theory was co-opted to lend credence to Portugal's colonial policy and determination to continue colonial rule in her large, remaining African empire. Freyre's Luso-Tropicalism theme was featured in the elaborate Fifth Centenary of the Death of Prince Henry the Navigator celebrations held in Lisbon in 1960 and in a massive series of publications produced in the 1960s to defend Portugal's policies in its empire, the first to be established and the last to decolonize in the Third World. Freyre's academic theory and his international prestige as a scholar who had put the sociology of Brazil on the world map were eagerly adopted and adapted by the Estado Novo. A major thesis of this interesting but somewhat disorganized mass of material was that the Portuguese were less racist and prejudiced toward the tropical peoples they encountered than were other Europeans.

   As African wars of insurgency began in Portugal's empire during 1961-64, and as the United Nations put pressures on Portugal, Luso-Tropicalism was tested and contested not only in academia and the press, but in international politics and diplomacy. Following the decolonization of Portugal's empire during 1974 and 1975 (although Macau remained the last colony to the late 1990s), debate over the notion of Luso-Tropicalism died down. With the onset of the 500-year anniversary celebrations of the Portuguese Age of Discoveries and Exploration, beginning in 1988, however, a whiff of the essence of Luso- Tropicalism reappeared in selected aspects of the commemorative literature.

    See also Commemorations, Portuguese historic.

an unconditional order in writing from one person (the drawer) to another (the drawee and signatory), requiring the drawee to pay on demand a sum to a specified person (the payee) or bearer. It is now usually used in overseas trade and the drawee may be a bank as opposed to an importer.

     The supplier or drawer usually submits the bill with the relative shipping documents. It is then anticipated by the drawee either as the agreed or implied method of payment. On receipt, the drawee either makes the required payment, or if payment is to be made at a future date, indicates acceptance by signing it.

     Wording on the bill will state when payment has to be made, for example, “60 days after date, we promise to pay...” means 60 days after the date of the bill; “60 days after sight, we promise to pay...” means 60 days after acceptance; and at sight means the bill is payable upon presentation.

     Once accepted, a bill of exchange is a negotiable instrument. The drawer can therefore obtain the money it represents by selling it to a financial institution at a discount. In the United Kingdom, the complex statutory law relating to these instruments is found in the Bills of Exchange Act (1882).

a statistical method used to analyze complex data and identify groupings that share common features. Cluster analysis is a form of multivariate analysis that attempts to explain variability in a set of data. It involves finding unifying elements that enable identification of groups or clusters displaying common characteristics. It could be used, for example, to analyze results of attitude research and delineate groups of respondents that share certain attitudes.

any of a set of techniques developed to aid the planning, monitoring, and controlling of complex projects and project resources. Network analysis is a tool of project management that involves breaking down a project into component parts or individual activities and recording them on a network diagram or flow chart. The resulting chart shows the interaction and interrelations between activities and can be used to determine project duration, time and resource limitations, and cost estimates. Constituent techniques include the criticalpath method and the program evaluation and review technique.

Also known as network flow analysis

the process by which a Web site presents customers with selected information on their specific needs. To do this, personal information is collected on the individual user, and employed to customize the Web site for that person. Used properly, personalization is a powerful tool that allows customers to access the right content more quickly, thus saving them valuable time. Personalization is particularly useful if a Web site contains a very large quantity of material, meaning that a visitor is slow in finding the information they seek. It also requires a large number of visitors to the Web site, because personalization systems are complex and expensive to install.

     Information on the customer is usually collected in one of two ways. Either the individual is asked to fill out a personal profile, perhaps informing the organization of the type of product and service he or she is interested in, or the organization uses software that tracks the way a customer uses the Web site. For example, a customer interested in Product X last week, might receive details of an update for Product X upon their next visit to the Web site. A popular method by which such tracking is carried out is the use of cookies, which reside on an individual’s browser and collect information on that person’s Web behavior. Because it requires the collection of personal information, personalization raises key privacy policy issues.

an accounting ratio of the income from an investment to the amount of the investment, used to measure financial performance.

There is a basic formula that will serve most needs, at least initially:

If $1,000 in capital is invested in stock, and one year later the investment yields $1,100, the rate of return of the investment is calculated like this:

Now, assume $1,000 is invested again. One year later, the investment grows to $2,000 in value, but after another year the value of the investment falls to $1,200. The rate of return after the first year is:

The rate of return after the second year is:

     The average annual return for the two years (also known as average annual arithmetic return) can be calculated using this formula:

     Accordingly:

The average annual rate of return is a percentage, but one that is accurate over only a short period, so this method should be used accordingly.

     The geometric or compound rate of return is a better yardstick for measuring investments over the long term, and takes into account the effects of compounding. This formula is more complex and technical.

     The real rate of return is the annual return realized on an investment, adjusted for changes in the price due to inflation. If 10% is earned on an investment but inflation is 2%, then the real rate of return is actually 8%.

Also known as return

SUBJECT AREA: Horology, Metallurgy

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Guillaume came from a family of clock-and watchmakers. He was educated at the Gymnasium in Neuchâtel and at Zurich Polytechnic, from which he received his doctorate in 1883 for a thesis on electrolytic capacitors. In the same year he joined the International Bureau of Weights and Measures at Sèvres in France, where he was to spend the rest of his working life. He retired as Director in 1936. At the bureau he was involved in distributing the national standards of the metre to countries subscribing to the General Conference on Weights and Measures that had been held in 1889. This made him aware of the crucial effect of thermal expansion on the lengths of the standards and he was prompted to look for alternative materials that would be less costly than the platinum alloys which had been used. While studying nickel steels he made the surprising discovery that the thermal expansion of certain alloy compositions was less than that of the constituent metals. This led to the development of a steel containing about 36 per cent nickel that had a very low thermal coefficient of expansion. This alloy was subsequently named "invar", an abbreviation of invariable. It was well known that changes in temperature affected the timekeeping of clocks by altering the length of the pendulum, and various attempts had been made to overcome this defect, most notably the mercury-compensated pendulum of Graham and the gridiron pendulum of Harrison. However, an invar pendulum offered a simpler and more effective method of temperature compensation and was used almost exclusively for pendulum clocks of the highest precision.

Changes in temperature can also affect the timekeeping of watches and chronometers, but this is due mainly to changes in the elasticity or stiffness of the balance spring rather than to changes in the size of the balance itself. To compensate for this effect Guillaume developed another more complex nickel alloy, "elinvar" (elasticity invariable), whose elasticity remained almost constant with changes in temperature. This had two practical consequences: the construction of watches could be simplified (by using monometallic balances) and more accurate chronometers could be made.

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See also: Le Roy, Pierre

SUBJECT AREA: Horology, Ports and shipping

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John Harrison was the son of a carpenter and was brought up to that trade. He was largely self-taught and learned mechanics from a copy of Nicholas Saunderson's lectures that had been lent to him. With the assistance of his younger brother, James, he built a series of unconventional clocks, mainly of wood. He was always concerned to reduce friction, without using oil, and this influenced the design of his "grasshopper" escapement. He also invented the "gridiron" compensation pendulum, which depended on the differential expansion of brass and steel. The excellent performance of his regulator clocks, which incorporated these devices, convinced him that they could also be used in a sea dock to compete for the longitude prize. In 1714 the Government had offered a prize of £20,000 for a method of determining longitude at sea to within half a degree after a voyage to the West Indies. In theory the longitude could be found by carrying an accurate timepiece that would indicate the time at a known longitude, but the requirements of the Act were very exacting. The timepiece would have to have a cumulative error of no more than two minutes after a voyage lasting six weeks.

In 1730 Harrison went to London with his proposal for a sea clock, supported by examples of his grasshopper escapement and his gridiron pendulum. His proposal received sufficient encouragement and financial support, from George Graham and others, to enable him to return to Barrow and construct his first sea clock, which he completed five years later. This was a large and complicated machine that was made out of brass but retained the wooden wheelwork and the grasshopper escapement of the regulator clocks. The two balances were interlinked to counteract the rolling of the vessel and were controlled by helical springs operating in tension. It was the first timepiece with a balance to have temperature compensation. The effect of temperature change on the timekeeping of a balance is more pronounced than it is for a pendulum, as two effects are involved: the change in the size of the balance; and the change in the elasticity of the balance spring. Harrison compensated for both effects by using a gridiron arrangement to alter the tension in the springs. This timekeeper performed creditably when it was tested on a voyage to Lisbon, and the Board of Longitude agreed to finance improved models. Harrison's second timekeeper dispensed with the use of wood and had the added refinement of a remontoire, but even before it was tested he had embarked on a third machine. The balance of this machine was controlled by a spiral spring whose effective length was altered by a bimetallic strip to compensate for changes in temperature. In 1753 Harrison commissioned a London watchmaker, John Jefferys, to make a watch for his own personal use, with a similar form of temperature compensation and a modified verge escapement that was intended to compensate for the lack of isochronism of the balance spring. The time-keeping of this watch was surprisingly good and Harrison proceeded to build a larger and more sophisticated version, with a remontoire. This timekeeper was completed in 1759 and its performance was so remarkable that Harrison decided to enter it for the longitude prize in place of his third machine. It was tested on two voyages to the West Indies and on both occasions it met the requirements of the Act, but the Board of Longitude withheld half the prize money until they had proof that the timekeeper could be duplicated. Copies were made by Harrison and by Larcum Kendall, but the Board still continued to prevaricate and Harrison received the full amount of the prize in 1773 only after George III had intervened on his behalf.

Although Harrison had shown that it was possible to construct a timepiece of sufficient accuracy to determine longitude at sea, his solution was too complex and costly to be produced in quantity. It had, for example, taken Larcum Kendall two years to produce his copy of Harrison's fourth timekeeper, but Harrison had overcome the psychological barrier and opened the door for others to produce chronometers in quantity at an affordable price. This was achieved before the end of the century by Arnold and Earnshaw, but they used an entirely different design that owed more to Le Roy than it did to Harrison and which only retained Harrison's maintaining power.

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See also: Burgi, Jost; Huygens, Christiaan

SUBJECT AREA: Steam and internal combustion engines

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William was the second son and one of eleven children of Samuel Priestman, who had moved to Hull after retiring as a corn miller in Kirkstall, Leeds, and who in retirement had become a director of the North Eastern Railway Company. The family were strict Quakers, so William was sent to the Quaker School in Bootham, York. He left school at the age of 17 to start an engineering apprenticeship at the Humber Iron Works, but this company failed so the apprenticeship was continued with the North Eastern Railway, Gateshead. In 1869 he joined the hydraulics department of Sir William Armstrong \& Company, Newcastle upon Tyne, but after a year there his father financed him in business at a small, run down works, the Holderness Foundry, Hull. He was soon joined by his brother, Samuel, their main business being the manufacture of dredging equipment (grabs), cranes and winches. In the late 1870s William became interested in internal combustion engines. He took a sublicence to manufacture petrol engines to the patents of Eugène Etève of Paris from the British licensees, Moll and Dando. These engines operated in a similar manner to the non-compression gas engines of Lenoir. Failure to make the two-stroke version of this engine work satisfactorily forced him to pay royalties to Crossley Bros, the British licensees of the Otto four-stroke patents.

Fear of the dangers of petrol as a fuel, reflected by the associated very high insurance premiums, led William to experiment with the use of lamp oil as an engine fuel. His first of many patents was for a vaporizer. This was in 1885, well before Ackroyd Stuart. What distinguished the Priestman engine was the provision of an air pump which pressurized the fuel tank, outlets at the top and bottom of which led to a fuel atomizer injecting continuously into a vaporizing chamber heated by the exhaust gases. A spring-loaded inlet valve connected the chamber to the atmosphere, with the inlet valve proper between the chamber and the working cylinder being camoperated. A plug valve in the fuel line and a butterfly valve at the inlet to the chamber were operated, via a linkage, by the speed governor; this is believed to be the first use of this method of control. It was found that vaporization was only partly achieved, the higher fractions of the fuel condensing on the cylinder walls. A virtue was made of this as it provided vital lubrication. A starting system had to be provided, this comprising a lamp for preheating the vaporizing chamber and a hand pump for pressurizing the fuel tank.

Engines of 2–10 hp (1.5–7.5 kW) were exhibited to the press in 1886; of these, a vertical engine was installed in a tram car and one of the horizontals in a motor dray. In 1888, engines were shown publicly at the Royal Agricultural Show, while in 1890 two-cylinder vertical marine engines were introduced in sizes from 2 to 10 hp (1.5–7.5 kW), and later double-acting ones up to some 60 hp (45 kW). First, clutch and gearbox reversing was used, but reversing propellers were fitted later (Priestman patent of 1892). In the same year a factory was established in Philadelphia, USA, where engines in the range 5–20 hp (3.7–15 kW) were made. Construction was radically different from that of the previous ones, the bosses of the twin flywheels acting as crank discs with the main bearings on the outside.

On independent test in 1892, a Priestman engine achieved a full-load brake thermal efficiency of some 14 per cent, a very creditable figure for a compression ratio limited to under 3:1 by detonation problems. However, efficiency at low loads fell off seriously owing to the throttle governing, and the engines were heavy, complex and expensive compared with the competition.

Decline in sales of dredging equipment and bad debts forced the firm into insolvency in 1895 and receivers took over. A new company was formed, the brothers being excluded. However, they were able to attend board meetings, but to exert no influence. Engine activities ceased in about 1904 after over 1,000 engines had been made. It is probable that the Quaker ethics of the brothers were out of place in a business that was becoming increasingly cut-throat. William spent the rest of his long life serving others.

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