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  • Dyerma (people)

    Zarma, a people of westernmost Niger and adjacent areas of Burkina Faso and Nigeria. The Zarma speak a dialect of Songhai, a branch of the Nilo-Saharan language family, and are considered to be a branch of the Songhai people. The Zarma live in the arid lands of the Sahel. Many live in the Niger

  • dyestuff

    Dye, substance used to impart colour to textiles, paper, leather, and other materials such that the colouring is not readily altered by washing, heat, light, or other factors to which the material is likely to be exposed. Dyes differ from pigments, which are finely ground solids dispersed in a

  • Dyfed (mythological kingdom)

    Pwyll: …in Celtic mythology, king of Dyfed, a beautiful land containing a magic caldron of plenty. He became a friend of Arawn, king of Annwn (the underworld), and exchanged shapes and kingdoms with him for a year and a day, thus gaining the name Pwyll Pen Annwn (“Head of Annwn”). With…

  • Dyfflin (national capital, Ireland)

    Dublin, city, capital of Ireland, located on the east coast in the province of Leinster. Situated at the head of Dublin Bay of the Irish Sea, Dublin is the country’s chief port, centre of financial and commercial power, and seat of culture. It is also a city of contrasts, maintaining an uneasy

  • Dyfrdwy, Afon (river, Wales and England, United Kingdom)

    River Dee, river in northern Wales and England, approximately 70 miles (110 km) long. It rises in the county of Gwynedd on the slopes of Dduallt, in Snowdonia National Park, and falls rapidly to Bala Lake. Its valley then runs northeast to Corwen and eastward past Llangollen. The Vale of Llangollen

  • Dygasiński, Adolf (Polish writer)

    Adolf Dygasiński, Polish short-story author and poet who is considered one of the outstanding Polish Naturalist writers. Dygasiński was a teacher by profession and a worshiper of science. He published about 50 volumes of short stories of uneven literary quality, the best pieces of which deal with

  • Dyhrenfurth, Norman (Swiss mountain climber)

    Mount Everest: The U.S. ascent of 1963: …led by the Swiss climber Norman Dyhrenfurth, who selected a team of 19 mountaineers and scientists from throughout the United States and 37 Sherpas. The purpose was twofold: to reach the summit and to carry out scientific research programs in physiology, psychology, glaciology, and meteorology. Of particular interest were the…

  • dying

    Death, the total cessation of life processes that eventually occurs in all living organisms. The state of human death has always been obscured by mystery and superstition, and its precise definition remains controversial, differing according to culture and legal systems. During the latter half of

  • Dying Animal, The (novel by Roth)

    Philip Roth: In The Dying Animal (2001; filmed as Elegy, 2008), an aging literary professor reflects on a life of emotional isolation. The Plot Against America (2004; TV miniseries 2020) tells a counterhistorical story of fascism in the United States during World War II.

  • Dying Centaur (sculpture by Bourdelle)

    Antoine Bourdelle: …he created another masterpiece, the Dying Centaur, in which he represented the defeat of paganism. In his later career, Bourdelle became known for his majestic public monuments. Never able to escape completely the shadow of Rodin, Bourdelle became a famous teacher, turning his studio into the Académie de la Grande-Chaumière.

  • Dying Swan, The (ballet)

    Michel Fokine: …also composed the brief solo The Dying Swan for the Russian ballerina Anna Pavlova. He continued to create ballets and three of his Mariinsky works were included in revised versions in the momentous season of the Ballets Russes that Diaghilev arranged in Paris in 1909: Le Pavillon d’Armide, Une Nuit…

  • Dyirbal (language)

    Australian Aboriginal languages: Grammar: …some Australian languages, such as Dyirbal, whose syntax could then be thought of as a kind of mirror image of the subject-object syntax of English and most other languages. (That is to say, direct objects in languages like Dyirbal have the special syntactic status that subjects have in English and…

  • dyke (civil engineering)

    Amsterdam: Early settlement and growth: …early inhabitants had to build dikes on both sides of the river, and about 1270 they built a dam between these dikes.

  • dyke (igneous rock)

    Dike, in geology, tabular or sheetlike igneous body that is often oriented vertically or steeply inclined to the bedding of preexisting intruded rocks; similar bodies oriented parallel to the bedding of the enclosing rocks are called sills. A dike set is composed of several parallel dikes; when the

  • Dyke, Greg (British businessman, journalist, and broadcaster)

    Greg Dyke, British businessman, journalist, and broadcaster best known as the director general (2000–04) of the British Broadcasting Corporation (BBC). Dyke was educated at a local west London grammar school. He subsequently tried various jobs, including a position as a management trainee for the

  • Dyke, Henry Van (American writer)

    Henry Van Dyke, U.S. short-story writer, poet, and essayist popular in the early decades of the 20th century. Educated at Princeton, Van Dyke graduated from its theological seminary in 1877 and became a Presbyterian minister. His early works, “The Story of the Other Wise Man” (1896) and “The First

  • Dyke, Mary Ann (American actress)

    Mary Ann Dyke Duff, American tragic actress who, at the peak of her career, was as highly regarded as the famed English actress Sarah Siddons. Mary Ann Dyke early took up the study of ballet under the ballet master of the King’s Theatre. In 1809 she and her two sisters made their dancing debut at

  • Dykes to Watch Out For (comic strip by Bechdel)

    Alison Bechdel: …known for the comic strip Dykes to Watch Out For (1983–2008), which introduced the so-called Bechdel Test; it evaluates movies on the basis of gender inequality.

  • Dykh-Tau (mountain, Transcaucasia)

    Caucasus: Physiography: …the western sector; Mounts Shkhara, Dykhtau, and Kazbek, all over 16,000 feet (4,800 metres), in the central sector; and Mounts Tebulosmta and Bazardyuzyu, both over 14,600 feet (4,550 metres), in the east. Spurs tonguing north and south from the main axis occasionally reach elevations approaching 10,000 feet (3,000 metres).

  • Dykhtau, Mount (mountain, Transcaucasia)

    Caucasus: Physiography: …the western sector; Mounts Shkhara, Dykhtau, and Kazbek, all over 16,000 feet (4,800 metres), in the central sector; and Mounts Tebulosmta and Bazardyuzyu, both over 14,600 feet (4,550 metres), in the east. Spurs tonguing north and south from the main axis occasionally reach elevations approaching 10,000 feet (3,000 metres).

  • Dylan (Celtic deity)

    D?n: …who bore Gwydion twin sons: Dylan, a sea god, and Lleu Llaw Gyffes (Lleu of the Dexterous Hand), whom many scholars consider analogous to the Irish god Lug.

  • Dylan, Bob (American musician)

    Bob Dylan, American folksinger who moved from folk to rock music in the 1960s, infusing the lyrics of rock and roll, theretofore concerned mostly with boy-girl romantic innuendo, with the intellectualism of classic literature and poetry. Hailed as the Shakespeare of his generation, Dylan sold tens

  • Dylan, Jakob (American musician)

    Bob Dylan: …had four children, including son Jakob, whose band the Wallflowers experienced pop success in the 1990s. Dylan was also stepfather to a child from Lowndes’s previous marriage. In 1978 Dylan mounted a yearlong world tour and released a studio album, Street-Legal, and a live album, Bob Dylan at Budokan. In…

  • Dyle Line (European history)

    World War II: The invasion of the Low Countries and France: …retreat to the Antwerp–Namur, or Dyle, Line. French and British divisions had just arrived on this Dyle Line, and General René Prioux’s two tank divisions went out from it to challenge the German advance. After a big battle on May 14, however, Prioux’s tanks had to retire to the consolidated…

  • Dyletsky, Mykola (Ukrainian artist)

    Ukraine: Music: The 17th-century composer Mykola Dyletsky introduced soprano singers to church choirs and emphasized emotional expression in his compositions. Ukrainian choral music reached its peak in the 18th and early 19th centuries in the works of Maksym Berezovsky, Dmytro Bortnyansky, and Artem Vedel.

  • Dylewska, Mount (mountain, Poland)

    Warmińsko-Mazurskie: Geography: The highest point is Mount Dylewska (1,023 feet [312 metres]). To the north is the Staropruska Lowland, and to the west are the Gdańsk Coastland and the Masurian Lakeland, site of Poland’s largest lakes—?niardwy (44 square miles [114 square km]) and Mamry (40 square miles [104 square km]). The…

  • Dylulenspegel (German literature)

    Till Eulenspiegel, German peasant trickster whose merry pranks were the source of numerous folk and literary tales. The historical Till Eulenspiegel is said to have been born at Kneitlingen, Brunswick, and to have died in 1350 at M?lln, Schleswig-Holstein, where his gravestone has been known since

  • Dym (novel by Turgenev)

    Smoke, novel by Ivan Turgenev, published in Russian in 1867 as Dym. Set in Baden-Baden, Germany, it combines a sensitive love story with political satire. While waiting in fashionable Baden to meet Tanya Shestoff, his fiancée, Grigory Litvinov, the young heir to a declining Russian estate,

  • dymantic pattern (biology)

    mammal: Skin and hair: Patterns may be startling (dymantic), as seen in the mane of the male lion or hamadryas baboon, warning (sematic), as seen in the bold pattern of skunks, or concealing (cryptic), perhaps the most common adaptation of pelage colour.

  • Dymaxion car (vehicle)

    R. Buckminster Fuller: Life: …his three-wheeled omnidirectional vehicle, the Dymaxion car. This automobile, the first streamlined car, could cross open fields like a jeep, accelerate to 120 miles (190 km) per hour, make a 180-degree turn in its own length, carry 12 passengers, and average 28 miles per gallon (12 km per litre) of…

  • Dymaxion house

    R. Buckminster Fuller: Life: …air-deliverable house, later called the Dymaxion house, which had its own utilities. He designed in 1928, and manufactured in 1933, the first prototype of his three-wheeled omnidirectional vehicle, the Dymaxion car. This automobile, the first streamlined car, could cross open fields like a jeep, accelerate to 120 miles (190 km)…

  • Dymling, Carl-Anders (Swedish filmmaker)

    Ingmar Bergman: Life: …and more importantly, he met Carl-Anders Dymling, the head of the Svensk Filmindustri. Dymling was sufficiently impressed by him to commission an original screenplay, Hets (1944; Frenzy, or Torment). This was directed by Alf Sj?berg, then Sweden’s leading film director, and was an enormous success, both at home and abroad.…

  • Dymphna, Saint (Irish martyr)

    Geel: …linked with the Irish martyr St. Dymphna. According to tradition, in the 7th century she was beheaded there by her demented father after she refused to marry him, and persons suffering from mental illness are said to have been cured at her tomb. A church was built in her honour,…

  • Dyn (American company)

    denial of service attack: … brought down the servers of Dyn, an American company that is in charge of much of the Internet’s domain name system (DNS). This attack interrupted much of North American Internet traffic. The Mirai botnet was not made up of infected computers but infected other devices, such as baby monitors, digital…

  • Dyna-Soar (United States space project)

    space exploration: The first human spaceflights: That was the mission of Dyna-Soar, another air force project. Dyna-Soar was to be a piloted reusable delta-winged vehicle that would be launched into orbit by a modified Titan ICBM and could carry out either bombing or reconnaissance missions over the Soviet Union or intercept a Soviet satellite in orbit.…

  • Dynabook (computer)

    computer: The graphical user interface: …portable computer they dubbed the Dynabook. The prototypes of this machine were expensive and resembled sewing machines, but the vision of the two researchers greatly influenced the evolution of products that today are dubbed notebook or laptop computers.

  • Dynamation (film technique)

    Ray Harryhausen: …that became known as “Dynamation,” used to make it appear that actors on film are interacting with animated models.

  • Dynamic Adaptive Total Area Coverage (cell phone)

    Martin Cooper: The result, the DynaTAC (Dynamic Adaptive Total Area Coverage) phone, was 23 cm (9 inches) tall and weighed 1.1 kg (2.5 pounds). It allowed 35 minutes of talk before its battery ran down.

  • dynamic compressor (mechanics)

    pneumatic device: Major types of pneumatic devices: …and (2) the velocity, or dynamic, type.

  • dynamic earphone

    earphone: …is provided by the so-called dynamic earphone, which ordinarily is made part of a headphone and equipped with a cushion to isolate the ears from other sound sources.

  • dynamic equilibrium (biology)

    homeostasis: …stability attained is actually a dynamic equilibrium, in which continuous change occurs yet relatively uniform conditions prevail.

  • dynamic equilibrium (geology)

    Earth sciences: Concepts of landform evolution: …graded condition, a state of dynamic equilibrium that is attained when the net effect of the flowing water is neither erosion of the bed nor deposition of sediment, when the landscape reflects a balance between the resistance of the rocks to erosion and the processes that are operative upon them.…

  • dynamic forecast model (meteorology)

    tropical cyclone: Landfall forecasts: Dynamic forecast models show the interaction of the tropical cyclone with its environment, but they require the use of large and powerful computers as well as very complete descriptions of the structure of the tropical cyclone and that of the surrounding environment. Computer models currently…

  • dynamic fusimotor axon (anatomy)

    human nervous system: Muscle spindles: One type, the dynamic fusimotor axon, increases the normal sensitivity of the primary ending to movement; the other type, the static fusimotor axon, decreases its sensitivity, causing it to behave much more like a secondary ending. Thus, the two types of efferent fibre provide a means whereby the…

  • Dynamic Hieroglyph of the Bal Tabarin (work by Severini)

    Gino Severini: In Dynamic Hieroglyph of the Bal Tabarin (1912), he retained the nightlife theme but incorporated the Cubist technique of collage (real sequins are fixed to the dancers’ dresses) and such nonsensical elements as a realistic nude riding a pair of scissors.

  • Dynamic Integrated Climate Economy model (environmental economics)

    William Nordhaus: …type of IAM called the Dynamic Integrated Climate Economy model, or DICE (a name intended to indicate that human beings were gambling with the future of the planet), Nordhaus quantified the long-run economic costs and benefits of various possible scenarios, including “business as usual” (no government intervention beyond policies already…

  • dynamic link library (computer code file)

    DLL, a file containing code for commonly used program functions on personal computers (PCs) that run the Microsoft Corporation’s Windows operating system. Linking is part of the process of creating a computer program in which programmers combine their new program codes with preexisting code

  • dynamic loudspeaker (audio device)

    electromechanical transducer: Electromagnetic speakers: Most loudspeakers are of the electromagnetic, or dynamic, variety, in which a voice coil moves in the gap of a permanent magnet when a time-varying current flows through the coil. The magnet is generally in the shape of a “W” or a ring.…

  • dynamic metamorphism

    metamorphism: Dynamic metamorphism, or cataclasis, results mainly from mechanical deformation with little long-term temperature change. Textures produced by such adjustments range from breccias composed of angular, shattered rock fragments to very fine-grained, granulated or powdered rocks with obvious foliation and lineation. Large, pre-existing mineral grains may…

  • dynamic meteorology

    climatology: …1960s a third main branch, dynamic meteorology, has emerged. It deals primarily with the numerical simulation of climate and climatic change, employing models of atmospheric processes based on the fundamental equations of dynamic meteorology. Other significant subdisciplines of climatology include bioclimatology and paleoclimatology.

  • dynamic microphone (electroacoustic device)

    microphone: …motion of a coil (dynamic microphone) or conductor (ribbon microphone) in a magnetic field, or in the twisting or bending of a piezoelectric crystal (crystal microphone). In each case, motion of the diaphragm produces a variation in the electric output. By proper design, a microphone may be given directional…

  • Dynamic Monarchianism (Christianity)

    Saint Agobard: Agobard wrote against the Adoptionist heresy (that Jesus was not the son of God by nature but by adoption) of Felix of Urgel (who was confined at Lyon from 800 to 818), against contemporary superstitions, and against the Jews. His zeal for reform led him to attack trial by…

  • dynamic nuclear polarization (physics)

    magnetic resonance: Combined electron-spin and nuclear magnetic resonances: …NMR, is called DNP (dynamic nuclear polarization).

  • dynamic pipe (meteorology)

    tornado: The dynamic pipe: As spin-up of the mesocyclone continues, its rotating action begins to reorganize airflow in the updraft. The local pressure field and the strongly curved wind field move toward a dynamic equilibrium called cyclostrophic balance. In this state, the pressure-gradient force, which acts to…

  • Dynamic Psychology (work by Woodworth)

    Robert S. Woodworth: His Dynamic Psychology (1918) attempted to explain behaviour by combining theories of motivation, perception, learning, and thinking, while his Psychology (1921) became a standard textbook. Throughout his career, he attempted to develop a unified theory of psychology based on thorough scientific observations and cautious generalizations from…

  • dynamic psychotherapy

    mental disorder: Dynamic psychotherapies: There are many variants of dynamic psychotherapy, most of which ultimately derive from the basic precepts of psychoanalysis. The fundamental approach of most dynamic psychotherapies can be traced to three basic theoretical principles or assertions: (1) human behaviour is prompted chiefly by emotional considerations,…

  • dynamic RAM (electronics)

    computer: Main memory: …gradually decays, IC memory is dynamic RAM (DRAM), which must have its stored values refreshed periodically (every 20 milliseconds or so). There is also static RAM (SRAM), which does not have to be refreshed. Although faster than DRAM, SRAM uses more transistors and is thus more costly; it is used…

  • dynamic random-access memory (electronics)

    computer: Main memory: …gradually decays, IC memory is dynamic RAM (DRAM), which must have its stored values refreshed periodically (every 20 milliseconds or so). There is also static RAM (SRAM), which does not have to be refreshed. Although faster than DRAM, SRAM uses more transistors and is thus more costly; it is used…

  • dynamic range (acoustics)

    compact disc: Dynamic range: Dynamic range is the ratio of the loudest undistorted sound to the quietest discernible sound, expressed in decibels, that a system is capable of producing. The compact disc’s dynamic range is about 90 decibels, compared with about 70 decibels on the best phonograph discs, thus…

  • dynamic selection (biology)

    evolution: Directional selection: The distribution of phenotypes in a population sometimes changes systematically in a particular direction. (See the centre column of the figure.) The physical and biological aspects of the environment are continuously changing, and over long periods of time the changes may be substantial.…

  • dynamic speaker (audio device)

    electromechanical transducer: Electromagnetic speakers: Most loudspeakers are of the electromagnetic, or dynamic, variety, in which a voice coil moves in the gap of a permanent magnet when a time-varying current flows through the coil. The magnet is generally in the shape of a “W” or a ring.…

  • dynamic stability (nautical science)

    ship: Dynamic stability: The capsizing of large ships that have not suffered flooding from hull damage is virtually unheard of, but it remains a serious hazard to smaller vessels that can experience large upsetting moments under normal operating conditions. A prominent example is a fishing vessel…

  • Dynamic style (Oceanic art)

    Oceanic art and architecture: Australia: …clan of spirit beings) or Dynamic style, is notable for linear human stick figures that wear ornaments, carry spears and boomerangs, and are occasionally endowed with animal heads. They are associated with paintings of now-extinct animals, such as the Tasmanian wolf (thylacine). The style is presumed to date from 18,000…

  • dynamic test (aerospace industry)

    aerospace industry: Prototype testing and certification: …is determined in static and dynamic tests. Ground testing requires an array of facilities, including ovens for applying high temperatures to materials, acoustic chambers to permit study of the effect of high-frequency engine noise on structures, rigs for measuring landing impacts, and variable-frequency vibrators for investigations of vibration and flutter…

  • dynamic variable (physics)

    mechanics: Configuration space: …to reduce the number of dynamic variables in a problem (the x, y, and z coordinates of each particle) to a smaller number of generalized dynamic variables, which need not even have the same dimensions as the original ones.

  • dynamic viscosity (physics)

    viscosity: The dimensions of dynamic viscosity are force × time ÷ area. The unit of viscosity, accordingly, is newton-second per square metre, which is usually expressed as pascal-second in SI units.

  • dynamic wind load

    bridge: Forces of nature: Dynamic wind load gives rise to vertical motion, creating oscillations in any direction. Like the breaking of an overused violin string, oscillations are vibrations that can cause a bridge to fail. If a deck is thin and not properly shaped and supported, it may experience…

  • dynamic-optimizing control (technology)

    control system: Basic principles.: Dynamic-optimizing control requires the control system to operate in such a way that a specific performance criterion is satisfied. This criterion is usually formulated in such terms that the controlled system must move from the original to a new position in the minimum possible time…

  • Dynamic-Tension (exercise)

    Charles Atlas: …an English naturopath, Atlas employed Dynamic-Tension principles to develop a mail-order course that was the basis for a multimillion-dollar bodybuilding business. Then in 1928, in partnership with Roman, he conducted one of the most-celebrated advertising campaigns in American history. Slogans such as “You can have a body like mine” were…

  • dynamical billiards (mathematics)

    Yakov Sinai: …also did notable work in dynamical billiards, in which the trajectory of a massless point is followed around a “billiards table,” for which the surface can take any shape (even three or more dimensions). The Sinai billiard, which he introduced in 1963, was a flat square with a circle cut…

  • dynamical similarity, principle of (fluid mechanics)

    fluid mechanics: Drag: …emphasizing because it enshrines the principle of dynamic similarity, which is heavily relied on by engineers whenever they use results obtained with models to predict the behaviour of much larger structures.

  • dynamical systems theory (mathematics)

    analysis: Dynamical systems theory and chaos: …differential equations, otherwise known as dynamical systems theory, which seeks to establish general properties of solutions from general principles without writing down any explicit solutions at all. Dynamical systems theory combines local analytic information, collected in small “neighbourhoods” around points of special interest, with global geometric and topological properties of…

  • dynamical time

    Dynamical time, specialized timescale used to describe the motion of objects in space. As a practical matter, time can be defined as that coordinate which can most simply be related to the evolution of closed systems. Proper time is the time measured by a clock in a reference system in which it is

  • dynamics (physics)

    Dynamics, branch of physical science and subdivision of mechanics that is concerned with the motion of material objects in relation to the physical factors that affect them: force, mass, momentum, energy. A brief treatment of dynamics follows. For full treatment, see mechanics. Dynamics can be

  • Dynamics of Faith (work by Tillich)

    Paul Tillich: Departure from Nazi Germany: …The Courage to Be and Dynamics of Faith, he argued that the deepest concern of humans drives them into confrontation with a reality that transcends their own finite existence. Tillich’s discussion of the human situation in these books shows a profound grasp of the problems brought to light by modern…

  • Dynamics of Prejudice (work by Janowitz and Bettelheim)

    Morris Janowitz: collaborated with Bruno Bettelheim on Dynamics of Prejudice (1950), a psychological and sociological study of racial and ethnic prejudice. The Professional Soldier (1960) spurred increased interest in civil-military relations. He is also the author of Sociology and the Military Establishment (1959; revised 1965) and Social Change and Prejudice (with Bettelheim,…

  • dynamism (philosophy)

    hylomorphism: are atomism, mechanism, and dynamism, all of which deny the intrinsic composition of metaphysical principles in bodies and recognize only physical principles, such as corpuscles, pure mathematical extension, or forces and energies. These theories agree also in denying the hylomorphist’s claim that intrinsic change can occur in the ultimate…

  • Dynamism of a Dog on a Leash (work by Balla)

    Giacomo Balla: One of his best-known works, Dynamism of a Dog on a Leash (1912), shows an almost frame-by-frame view of a woman walking a dog on a boulevard. The work illustrates his principle of simultaneity—i.e., the rendering of motion by simultaneously showing many aspects of a moving object. This interest in…

  • dynamite (explosive)

    Dynamite, blasting explosive, patented in 1867 by the Swedish physicist Alfred Nobel. Dynamite is based on nitroglycerin but is much safer to handle than nitroglycerin alone. By mixing the nitroglycerin with kieselguhr, a porous siliceous earth, in proportions that left an essentially dry and

  • dynamo (instrument)

    Electric generator, any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. Generators also produce the electrical power required for automobiles, aircraft, ships, and trains. The mechanical

  • dynamo effect (physics)

    plasma: Applications of plasmas: One suggestion depends on the dynamo effect. If a plasma moves perpendicular to a magnetic field, an electromotive force, according to Faraday’s law, is generated in a direction perpendicular to both the direction of flow of the plasma and the magnetic field. This dynamo effect can drive a current in…

  • Dynamo Kiev (Ukrainian football team)

    Dynamo Kiev, Ukrainian professional football (soccer) team located in Kiev. Dynamo Kiev was one of the strongest teams in the former Union of Soviet Socialist Republics (Soviet Union) and is the dominant team in the Ukrainian league. In 1923 a system of sports and physical education clubs and

  • dynamo mechanism (geophysics)

    Dynamo theory, geophysical theory that explains the origin of Earth’s main magnetic field in terms of a self-exciting (or self-sustaining) dynamo. In this dynamo mechanism, fluid motion in Earth’s outer core moves conducting material (liquid iron) across an already existing weak magnetic field and

  • dynamo region (atmospheric science)

    geomagnetic field: The ionospheric dynamo: Above Earth’s surface is the next source of magnetic field, the ionospheric dynamo—an electric current system flowing in the planet’s ionosphere. Beginning at about 50 kilometres and extending above 1,000 kilometres with a maximum at 400 kilometres, the ionosphere is formed primarily by…

  • dynamo theory (geophysics)

    Dynamo theory, geophysical theory that explains the origin of Earth’s main magnetic field in terms of a self-exciting (or self-sustaining) dynamo. In this dynamo mechanism, fluid motion in Earth’s outer core moves conducting material (liquid iron) across an already existing weak magnetic field and

  • Dynamo, Operation (World War II)

    Dunkirk evacuation, (1940) in World War II, the evacuation of the British Expeditionary Force (BEF) and other Allied troops from the French seaport of Dunkirk (Dunkerque) to England. Naval vessels and hundreds of civilian boats were used in the evacuation, which began on May 26. When it ended on

  • dynamometer (measurement instrument)

    Dynamometer, device for measuring mechanical force, or power, transmitted by a rotating shaft. Since power is the product of torque (turning force) and angular speed, all power-measuring dynamometers are essentially torque-measuring devices; the shaft speed is measured separately. Among

  • dynamophone (musical instrument)

    Telharmonium, earliest musical instrument to generate sound electrically. It was invented in the United States by Thaddeus Cahill and introduced in 1906. The electrophonic instrument was of the electromechanical type, and it used rotating electromagnetic generators (and thus was a predecessor of t

  • dynamotor (electronics)

    motor generator: …combination has been termed a dynamotor. In some sets, there may be more than one coupled generator. Motor generator is also used to denote an electric generator and a driving motor, such as a gasoline or diesel engine.

  • Dynastes hercules (insect)

    rhinoceros beetle: Some species, such as the Hercules beetle (Dynastes hercules), can grow to more than 18 cm (7 inches) long, of which 10 cm (4 inches) may be horn. The Hercules beetle and rhinoceros beetle (D. neptunus) are spectacular, resembling an enormous pair of pincers. Found in American tropical forests, these…

  • Dynastes neptunus (insect, Dynastes species)

    rhinoceros beetle: The Hercules beetle and rhinoceros beetle (D. neptunus) are spectacular, resembling an enormous pair of pincers. Found in American tropical forests, these two species have double horns that are oriented vertically. The upper horn curves forward from behind the head, whereas the lower emerges from the head itself. Another…

  • Dynastes tityus (insect)

    Eastern Hercules beetle, (Dynastes tityus), a large, easily recognized insect of the Dynastinae subfamily of the beetle family Scarabaeidae (order Coleoptera). The eastern Hercules beetle is closely related to the rhinoceros and elephant beetles. Hornlike structures on the thorax (region behind the

  • Dynastinae (insect subfamily)

    Rhinoceros beetle, (subfamily Dynastinae), any of numerous species of beetles, some of which are among the largest beetles on Earth, named for the impressive hornlike structures on the frontal portions of males. These beetles have rounded, convex backs, and their coloration varies from black to

  • Dynasts, a Drama of the Napoleonic Wars, in Three Parts, Nineteen Acts, and One Hundred and Thirty Scenes, The (work by Hardy)

    The Dynasts, verse drama by Thomas Hardy, published in three parts in 1903, 1906, and 1908 and together in one volume in 1910. The monumental work, written mostly in blank verse with some scenes, descriptive connecting sequences, and stage directions written in prose, depicts the career of Napoleon

  • Dynasts, The (work by Hardy)

    The Dynasts, verse drama by Thomas Hardy, published in three parts in 1903, 1906, and 1908 and together in one volume in 1910. The monumental work, written mostly in blank verse with some scenes, descriptive connecting sequences, and stage directions written in prose, depicts the career of Napoleon

  • Dynasty (American television series)

    Television in the United States: Nighttime soaps: …spate of Dallas imitations included Dynasty (ABC, 1981–89) and Falcon Crest (CBS, 1981–90).

  • dynasty

    Dynasty, a family or line of rulers, a succession of sovereigns of a country belonging to a single family or tracing their descent to a common ancestor (Greek dynadeia, "sovereignty"). The term is particularly used in the history of ancient Egypt as a convenient means of arranging the

  • Dynasty of Death (novel by Caldwell)

    Taylor Caldwell: …published work, a novel entitled Dynasty of Death (1938), created a minor sensation in its portrayal of a family of munitions makers. The saga was continued in The Eagles Gather (1940) and The Final Hour (1944). Her other books, typically dramatic tales set in the past and nearly all very…

  • DynaTAC (cell phone)

    Martin Cooper: The result, the DynaTAC (Dynamic Adaptive Total Area Coverage) phone, was 23 cm (9 inches) tall and weighed 1.1 kg (2.5 pounds). It allowed 35 minutes of talk before its battery ran down.

  • dynatron (electronics)

    tetrode: …form of tetrode was the dynatron, a vacuum tube that was operated with screen-grid voltage higher than plate voltage so that the tube exhibited negative resistance (i.e., plate current decreased when plate voltage increased), a useful characteristic in oscillator circuits. The screen grid also caused an electron-acceleration effect that increased…

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