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  • Energy Conversion | Britannica.com
    14 percent or less on a dry ash free basis and it has calorific Argonne National Laboratory the first U S national research laboratory located in Argonne Illinois some 40 km 25 miles southwest of Chicago and operated by the University of Chicago for the U S Department of Energy It was founded in 1946 to conduct basic nuclear physics Armstrong of Cragside William George Armstrong Baron British industrialist and engineer who invented high pressure hydraulic machinery and revolutionized the design and manufacture of guns Armstrong abandoned his Newcastle law practice in 1847 to devote full time to scientific experimentation He founded asphalt black or brown petroleum like material that has a consistency varying from viscous liquid to glassy solid It is obtained either as a residue from the distillation of petroleum or from natural deposits Asphalt consists of compounds of hydrogen and carbon asphaltite any of several naturally occurring hard solid bitumens whose chief constituents asphaltenes have very large molecules Asphaltites are dark brown to black in colour They are insoluble in petroleum naphthas and thus require heating to release their battery in electricity and electrochemistry any of a class of devices that convert chemical energy directly into electrical energy Although the term battery in strict usage designates an assembly of two or more galvanic cells capable of such energy conversion bellows mechanical contrivance for creating a jet of air consisting usually of a hinged box with flexible sides which expands to draw in air through an inward opening valve and contracts to expel the air through a nozzle The bellows was invented in the European biodiesel a fuel made primarily from oily plants such as the soybean or oil palm and to a lesser extent from other oily sources such as waste cooking fat from restaurant deep frying Biodiesel which has found greatest acceptance in Europe is used in diesel biofuel any fuel that is derived from biomass that is plant material or animal waste Since such feedstock material can be replenished readily biofuel is considered to be a source of renewable energy unlike fossil fuels such as petroleum coal and natural biogenic gas any gas critical for and produced by living organisms Biogenic gases in the atmosphere play a role in the dynamics of Earth s planetary radiation budget the thermodynamics of the planet s moist atmosphere and indirectly the mechanics of the fluid bitumen dense highly viscous petroleum based hydrocarbon that is found in deposits such as oil sands and pitch lakes natural bitumen or is obtained as a residue of the distillation of crude oil refined bitumen In some areas particularly in the United bituminous coal the most abundant form of coal intermediate in rank between subbituminous coal and anthracite according to the coal classification used in the United States and Canada In Britain bituminous coal is commonly called steam coal and in Germany the blast furnace a vertical shaft furnace that produces liquid metals by the reaction of a flow of air introduced under

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  • Materials | Britannica.com
    sand and silt with good plastic qualities that will dry to a hard uniform mass In areas with arid advanced ceramics substances and processes used in the development and manufacture of ceramic materials that exhibit special properties Ceramics as is pointed out in the article ceramic composition and properties are traditionally described as inorganic nonmetallic advanced structural ceramics ceramic materials that demonstrate enhanced mechanical properties under demanding conditions Because they serve as structural members often being subjected to mechanical loading they are given the name structural ceramics Ordinarily for structural aggregate in building and construction material used for mixing with cement bitumen lime gypsum or other adhesive to form concrete or mortar The aggregate gives volume stability resistance to wear or erosion and other desired physical properties to the alkali metal any of the six chemical elements that make up Group 1 Ia of the periodic table namely lithium Li sodium Na potassium K rubidium Rb cesium Cs and francium Fr The alkali metals are so called because reaction with water forms alkalies alkaline earth metal any of the six chemical elements that comprise Group 2 IIa of the periodic table The elements are beryllium Be magnesium Mg calcium Ca strontium Sr barium Ba and radium Ra Occurrence properties and uses Prior to the 19th century alkyd resin a complex oil modified polyester that serves as the film forming agent in some paints and clear coatings Developed in the 1920s alkyd based enamel paints were once one of the most important types of surface coating Owing to their incorporation of aluminum Al chemical element a lightweight silvery white metal of main Group 13 IIIa or boron group of the periodic table Aluminum is the most abundant metallic element in Earth s crust and the most widely used nonferrous metal Because of its chemical aluminum processing preparation of the ore for use in various products Aluminum or aluminium Al is a silvery white metal with a melting point of 660 C 1 220 F and a density of 2 7 grams per cubic centimetre The most abundant metallic element it constitutes 8 1 Amelung glass American glass produced from 1784 to about 1795 by John Frederick Amelung a native of Bremen in Germany Financed by German and American promoters Amelung founded the New Bremen Glassmanufactory near Frederick Md U S and attempted to establish annealing treatment of a metal or alloy by heating to a predetermined temperature holding for a certain time and then cooling to room temperature to improve ductility and reduce brittleness Process annealing is carried out intermittently during the working anodizing method of plating metal for such purposes as corrosion resistance electrical insulation thermal control abrasion resistance sealing improving paint adhesion and decorative finishing Anodizing consists of electrically depositing an oxide film from anvil iron block on which metal is placed to be shaped originally by hand with a hammer The blacksmith s anvil is usually of wrought iron but sometimes of cast iron with a smooth working

    Original URL path: http://www.britannica.com/topic-browse/Technology/Materials (2016-02-13)
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  • Medical Technology | Britannica.com
    worked in stereochemistry and adjuvant substance that enhances the effect of a particular medical treatment Administration of one drug may enhance the effect of another In anesthesia for example sedative drugs are customarily given before an operation to reduce the quantity of anesthetic adrenergic drug any of various drugs that mimic or interfere with the functioning of the sympathetic nervous system by affecting the release or action of norepinephrine and epinephrine These hormones which are also known as noradrenaline and adrenaline are secreted air pollution control the techniques employed to reduce or eliminate the emission into the atmosphere of substances that can harm the environment or human health The control of air pollution is one of the principal areas of pollution control along with wastewater treatment allopurinol drug used in the treatment of gout a disease that is characterized by severe inflammation in one or more of the joints of the extremities Allopurinol inhibits an enzyme that is necessary to form uric acid a substance present in abnormally large amounts amantadine drug used to treat infections caused by influenza type A virus the most common cause of influenza epidemics Amantadine and its derivative rimantadine can be used successfully in the prevention and treatment of influenza A however these agents have aminoglycoside any of several natural and semisynthetic compounds that are used to treat bacterial diseases The term aminoglycoside is derived from the chemical structure of these compounds which are made up of amino groups NH 2 attached to glycosides derivatives amphetamine prototype of a series of synthetic drugs all called amphetamines that have pronounced stimulatory actions on the central nervous system Amphetamine itself is a colourless liquid with an acrid taste and a faint odour the most widely used preparation ampicillin drug used in the treatment of various infections including

    Original URL path: http://www.britannica.com/topic-browse/Technology/Medical-Technology (2016-02-13)
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  • Production Process | Britannica.com
    containing aluminum bronze any of a group of strong corrosion resistant alloys of copper containing from 4 to 15 percent aluminum and small amounts of other metals used to make many machine parts and tools Because of their golden colour and high tarnish resistance the alloys aluminum processing preparation of the ore for use in various products Aluminum or aluminium Al is a silvery white metal with a melting point of 660 C 1 220 F and a density of 2 7 grams per cubic centimetre The most abundant metallic element it constitutes 8 1 amalgam alloy of mercury and one or more other metals Amalgams are crystalline in structure except for those with a high mercury content which are liquid Known since early times they were mentioned by Pliny the Elder in the 1st century ad In dentistry American System production of many identical parts and their assembly into finished products Though Eli Whitney has been credited with this development the ideas had appeared earlier in Europe and were being practiced in arms factories in the United States See armoury annealing treatment of a metal or alloy by heating to a predetermined temperature holding for a certain time and then cooling to room temperature to improve ductility and reduce brittleness Process annealing is carried out intermittently during the working anodizing method of plating metal for such purposes as corrosion resistance electrical insulation thermal control abrasion resistance sealing improving paint adhesion and decorative finishing Anodizing consists of electrically depositing an oxide film from anvil iron block on which metal is placed to be shaped originally by hand with a hammer The blacksmith s anvil is usually of wrought iron but sometimes of cast iron with a smooth working surface of hardened steel A projecting conical beak or horn at Apple

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  • Tools and Machinery | Britannica.com
    from Middle English aker from Old English actinometer in chemistry a substance or a mixture of substances that reacts through the action of light and that because of the easily determined quantitative relationship between the extent of the reaction and the energy of the absorbed light is used as a standard Adobe Photoshop computer application software used to edit and manipulate digital images Photoshop was developed in 1987 by the American brothers Thomas and John Knoll who sold the distribution license to Adobe Systems Incorporated in 1988 Photoshop was originally adz hand tool for shaping wood One of the earliest tools it was widely distributed in Stone Age cultures in the form of a handheld stone chipped to form a blade By Egyptian times it had acquired a wooden haft or handle with a copper or bronze blade AEG AG former German electronics and electrical equipment company As one of Germany s leading industrial companies through much of the 19th and 20th centuries AEG manufactured products for industrial and domestic use The company was founded in Berlin in agent a computer program that performs various actions continuously and autonomously on behalf of an individual or an organization For example an agent may archive various computer files or retrieve electronic messages on a regular schedule Such simple Agent Orange mixture of herbicides that U S military forces sprayed in Vietnam from 1962 to 1971 during the Vietnam War for the dual purpose of defoliating forest areas that might conceal Viet Cong and North Vietnamese forces and destroying crops that might feed AGP graphics hardware technology first introduced in 1996 by the American integrated circuit manufacturer Intel Corporation AGP uses a direct channel to a computer s CPU central processing unit and system memory unlike PCI peripheral component interconnect Aiken Howard Hathaway mathematician who invented the Harvard Mark I forerunner of the modern electronic digital computer Aiken did engineering work while he attended the University of Wisconsin Madison After completing his doctorate at Harvard University in 1939 he remained air brake either of two kinds of braking systems The first used by railroad trains trucks and buses operates by a piston driven by compressed air from reservoirs connected to brake cylinders When air pressure in the brake pipe is reduced air is automatically air gun weapon based on the principle of the primitive blowgun that shoots bullets pellets or darts by expansion of compressed air Most modern air guns are inexpensive BB guns named for the size of the shot fired The best of these develop about half the air spring load carrying component of an air suspension system used on machines automobiles and buses A system used on buses consists of an air compressor an air supply tank leveling valves check valves bellows and connecting piping Basically an air spring air conditioning the control of temperature humidity purity and motion of air in an enclosed space independent of outside conditions An early method of cooling air as practiced in India was

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  • Transportation | Britannica.com
    of the Aerial Experiment Association AEA in 1908 For a table of pioneer aircraft see history of flight Alexander Graham Bell one of the founders of the AEA gave the third and most famous of the powered Aerial Experiment Association AEA organization that gathered together a group of young aviators and designers for the purpose of developing heavier than air flying machines It was founded in 1907 and funded for slightly longer than one year by the American inventor Alexander Graham aerobatics maneuvers in which an aircraft is flown under precise control in unusual attitudes the position of an aircraft determined by the relationship between its axes and a reference such as the horizon A myriad of aerobatic maneuvers exist some of the better known Agnelli Giovanni founder of the Fiat Fabbrica Italiana Automobili Torino automobile company and the leading Italian industrialist of the first half of the 20th century Agnelli attended the military school at Modena but he quit the army in 1892 In 1899 he was one aileron movable part of an airplane wing that is controlled by the pilot and permits him to roll the aircraft around its longitudinal axis Ailerons are thus used primarily to bank the aircraft for turning Ailerons have taken different forms through the years Air Force One any aircraft of the U S Air Force that is carrying the president of the United States Strictly speaking Air Force One is the radio call sign adopted by any Air Force plane while the president is aboard In common parlance however the call sign has air law the body of law directly or indirectly concerned with civil aviation Aviation in this context extends to both heavier than air and lighter than air aircraft Air cushion vehicles are not regarded as aircraft by the International Civil Aviation Organization air racing sport of racing airplanes either over a predetermined course or cross country up to transcontinental limits Air racing dates back to 1909 when the first international meet was held at Reims France Sporting aviation dates back to the early days of air space in international law the space above a particular national territory treated as belonging to the government controlling the territory It does not include outer space which under the Outer Space Treaty of 1967 is declared to be free and not subject air cushion machine any of the machines characterized by movement in which a significant portion of the weight is supported by forces arising from air pressures developed around the craft as a result of which they hover in close proximity to the Earth s surface It is Airbus Industrie European aircraft manufacturing consortium formed in 1970 to fill a market niche for short to medium range high capacity jetliners It is now one of the world s top two commercial aircraft manufacturers competing directly with the American Boeing aircraft carrier naval vessel from which airplanes may take off and on which they may land As early as November 1910 an American

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  • Technology - 3 | Britannica.com
    Cloning happens all the time in nature for example when a cell replicates itself asexually without any genetic alteration or recombination Prokaryotic organisms organisms cloud seeding deliberate introduction into clouds of various substances that act as condensation nuclei or ice nuclei in an attempt to induce precipitation Although the practice has many advocates including national state and provincial government officials some cloud whitening untested geoengineering technique designed to increase the reflectance of Earth s cloud cover to reduce the amount of incoming solar radiation striking Earth s surface This technique would rely upon towering spraying devices placed on land and mounted clutch device for quickly and easily connecting or disconnecting a pair of rotatable coaxial shafts Clutches are usually placed between the driving motor and the input shaft to a machine and provide a convenient means for starting and stopping the machine coal mining extraction of deposits from the surface of the Earth and from the underground Coal is the most abundant fossil fuel on Earth Its predominant use has always been for producing heat energy It was the basic energy source that fueled the Industrial Revolution cobalt processing preparation of the metal for use in various products Below 417 C 783 F cobalt Co has a stable hexagonal close packed crystal structure At higher temperatures up to the melting point of 1 495 C 2 723 F the stable form is face centred cubic cogeneration in power systems use of steam for both power generation and heating High temperature high pressure steam from a boiler and superheater first passes through a turbine to produce power see steam engine It then exhausts at a temperature and pressure coin glass glassware usually in the form of wineglasses goblets or tankards enclosing a coin either in the foot or in the hollow knop of the stem rarely in an interior bulb A Venetian specimen of coin glass dated 1647 is known but the principal occurrence collimator device for changing the diverging light or other radiation from a point source into a parallel beam This collimation of the light is required to make specialized measurements in spectroscopy and in geometric and physical optics An optical collimator Colossus early electronic computer built during World War II in England The exigencies of war gave impetus and funding to computer research In Britain for example the impetus was code breaking The Ultra project was funded with much secrecy to develop the column in architecture a vertical element usually a rounded shaft with a capital and a base which in most cases serves as a support A column may also be nonstructural used for a decorative purpose or as a freestanding monument In the field of architectural commercial fishing the taking of fish and other seafood and resources from oceans rivers and lakes for the purpose of marketing them Fishing is one of the oldest employments of humankind Ancient heaps of discarded mollusk shells some from prehistoric times have been computer device for processing storing and displaying information Computer once meant a person who did computations but now the term almost universally refers to automated electronic machinery The first section of this article focuses on modern digital electronic computer architecture Internal structure of a digital computer encompassing the design and layout of its instruction set and storage registers The architecture of a computer is chosen with regard to the types of programs that will be run on it business scientific general purpose computer chip integrated circuit or small wafer of semiconductor material embedded with integrated circuitry Chips comprise the processing and memory units of the modern digital computer see microprocessor RAM Chip making is extremely precise and is usually done computer circuitry Complete path or combination of interconnected paths for electron flow in a computer Computer circuits are binary in concept having only two possible states They use on off switches transistors that are electrically opened and closed in nanoseconds computer graphics production of images on computers for use in any medium Images used in the graphic design of printed material are frequently produced on computers as are the still and moving images seen in comic strips and animations The realistic images viewed and computer memory device that is used to store data or programs sequences of instructions on a temporary or permanent basis for use in an electronic digital computer Computers represent information in binary code written as sequences of 0s and 1s Each binary digit computer network two or more computers that are connected with one another for the purpose of communicating data electronically Besides physically connecting computer and communication devices a network system serves the important function of establishing a cohesive computer program detailed plan or procedure for solving a problem with a computer more specifically an unambiguous ordered sequence of computational instructions necessary to achieve such a solution The distinction between computer programs and equipment is often computer programming language any of various languages for expressing a set of detailed instructions for a digital computer Such instructions can be executed directly when they are in the computer manufacturer specific numerical form known as machine language after a simple substitution computer security the protection of computer systems and information from harm theft and unauthorized use Computer hardware is typically protected by the same means used to protect other valuable or sensitive equipment namely serial numbers doors and locks and computer simulation the use of a computer to represent the dynamic responses of one system by the behaviour of another system modeled after it A simulation uses a mathematical description or model of a real system in the form of a computer program This model is composed concrete in construction structural material consisting of a hard chemically inert particulate substance known as aggregate usually sand and gravel that is bonded together by cement and water Among the ancient Assyrians and Babylonians the bonding substance conductive ceramics advanced industrial materials that owing to modifications in their structure serve as electrical conductors In addition to the well

    Original URL path: http://www.britannica.com/topic-browse/Technology/3 (2016-02-13)
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  • Technology - 4 | Britannica.com
    or folding handheld device used throughout the world since ancient times for cooling air circulation or ceremony and as a sartorial accessory The rigid fan has a handle or stick with a rigid leaf or mount The folding farm building any of the structures used in farming operations which may include buildings to house families and workers as well as livestock machinery and crops The basic unit of commercial agricultural operation throughout history and worldwide is the farm farm machinery mechanical devices including tractors and implements used in farming to save labour Farm machines include a great variety of devices with a wide range of complexity from simple hand held implements used since prehistoric times to the complex harvesters fat processing method by which animal and plant substances are prepared for eating by humans The oil and fat products used for edible purposes can be divided into two distinct classes liquid oils such as olive oil peanut oil soybean oil or sunflower oil and fence barrier erected to confine or exclude people or animals to define boundaries or to decorate Timber soil stone and metal are widely used for fencing Fences of living plants have been made in many places such as the hedges of Great Britain and fibre in textile production basic unit of raw material having suitable length pliability and strength for conversion into yarns and fabrics A fibre of extreme length is a filament Fibres can occur naturally or can be produced artificially See Man Made fibre man made fibre whose chemical composition structure and properties are significantly modified during the manufacturing process Man made fibres are spun and woven into a huge number of consumer and industrial products including garments such as shirts scarves filter in photography device used to selectively modify the component wavelengths of mixed e g white light before it strikes the film Filters may be made of coloured glass plastic gelatin or sometimes a coloured liquid in a glass cell They are most fire prevention and control the prevention detection and extinguishment of fires including such secondary activities as research into the causes of fire education of the public about fire hazards and the maintenance and improvement of fire fighting equipment Until after World fish processing preparation of seafood and freshwater fish for human consumption The word fish is commonly used to describe all forms of edible finfish mollusks e g clams and oysters and crustaceans e g crabs and lobsters that inhabit an aquatic environment fish finder in commercial fishing high frequency sonar device for locating schools of fish It transmits sound waves downward and receives echoes from the bottom of the sea or from intervening schools of fish also indicating distance from ship to fish Two different fishery harvesting of fish shellfish and sea mammals as a commercial enterprise or the location or season of commercial fishing Fisheries range from small family operations relying on traditional fishing methods to large corporations using large fleets and fishing the sport of catching fish freshwater or saltwater typically with rod line and hook Like hunting fishing originated as a means of providing food for survival Fishing as a sport however is of considerable antiquity An Egyptian angling scene flare combustible device used to emit a dazzlingly bright light for signaling or illumination on railroads and highways and in military operations In pyrotechnics the term is applied either to a coloured fire composition burned in a loose heap or to a similar flash lamp any of several devices that produce brief intense emissions of light useful in photography and in the observation of objects in rapid motion The first flash lamp used in photography was invented in Germany in 1887 it consisted of a trough filled with flatware spoons forks and serving implements used at the table The term flatware was introduced toward the end of the 19th century Strictly speaking it excludes knives which are classified as cutlery although in common American usage knives are generally flight history of development of heavier than air flying machines Important landmarks and events along the way to the invention of the airplane include an understanding of the dynamic reaction of lifting surfaces or wings building absolutely reliable engines that floor rigid building assembly that divides space horizontally into stories It forms the bottom of a room It may consist of joist supported wood planks or panels decking or panels supported by wood or steel beams a slab of stone or concrete on the ground floor covering material made from textiles felts resins rubber or other natural or man made substances applied or fastened to or laid upon the level base surface of a room to provide comfort durability safety and decoration Such materials include both handmade flow meter Device that measures the velocity of a gas or liquid It has applications in medicine as well as in chemical engineering aeronautics and meteorology Examples include pitot tubes venturi tubes and rotameters tapered graduated tubes with a float flywheel heavy wheel attached to a rotating shaft so as to smooth out delivery of power from a motor to a machine The inertia of the flywheel opposes and moderates fluctuations in the speed of the engine and stores the excess energy for intermittent use To focusing ability of the lens to alter its shape to allow objects to be seen clearly In humans the forward surface of the lens is made more convex for seeing objects up close At the same time the pupil becomes smaller and the two eyes turn inward i e cross fog dispersal artificial dissipation of fogs usually by seeding or heating It is done primarily at airports to improve visibility Many attempts have been made to clear fogs at temperatures above freezing 0 C 32 F by seeding them with salt particles by downwash food additive any of various chemical substances added to foods to produce specific desirable effects Additives such as salt spices and sulfites have been used since ancient times to preserve

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