petroleum refining: Catalytic cracking: …was the commercialization of the fluid catalytic cracking process in 1942 that really established the foundation of modern petroleum refining. The process not only provided a highly efficient means of converting high-boiling gas oils into naphtha to meet the rising demand for high-octane gasoline, but it also represented a breakthrough…

automatic transmission: …may be either a two-element fluid coupling or a three-element torque converter. When the car loses speed the transmission automatically shifts back from high to low gear.

fluid mechanics: Hydrodynamics: Up to now the focus has been fluids at rest. This section deals with fluids that are in motion in a steady fashion such that the fluid velocity at each given point in space is not changing with time. Any flow pattern…

fluid mechanics: …mechanics, science concerned with the response of fluids to forces exerted upon them. It is a branch of classical physics with applications of great importance in hydraulic and aeronautical engineering, chemical engineering, meteorology, and zoology.

human behaviour: Cognition: Fluid intelligence, measured by tests that minimize the role of cultural knowledge, reflects the degree to which the individual has developed unique qualities of thinking through incidental learning. Crystallized intelligence, measured by tests that maximize the role of cultural knowledge, reflects the degree to which…

fluid mechanics, science concerned with the response of fluids to forces exerted upon them. It is a branch of classical physics with applications of great importance in hydraulic and aeronautical engineering, chemical engineering, meteorology, and zoology. The most familiar fluid is of course

hydraulic power, power transmitted by the controlled circulation of pressurized fluid, usually a water-soluble oil or water–glycol mixture, to a motor that converts it into a mechanical output capable of doing work on a load. Hydraulic power systems have greater flexibility than mechanical and

fluid mechanics: Basic properties of fluids: …arises when adjacent layers of fluid slip over one another. It follows that the shear stresses are everywhere zero in a fluid at rest and in equilibrium, and from this it follows that the pressure (that is, force per unit area) acting perpendicular to all planes in the fluid is…

resistance training: Fluid resistance: The classic example of fluid resistance training is swimming. The fluid resistance in that case is water. Fluid resistance is also a factor in activities such as cycling, baseball, and golf. Those activities are examples of air resistance. The resistance from water and air come in two forms, surface…

lubrication: Fluid-film lubrication.: Interposing a fluid film that completely separates sliding surfaces results in this type of lubrication. The fluid may be introduced intentionally, as the oil in the main bearings of an automobile, or unintentionally, as in the case of water between a smooth rubber…

lubrication: Fluid-film lubrication.: Interposing a fluid film that completely separates sliding surfaces results in this type of lubrication. The fluid may be introduced intentionally, as the oil in the main bearings of an automobile, or unintentionally, as in the case of water between a smooth rubber…

air warfare: Air superiority: One solution was the fluid-four, in which two fighters flying 300 yards apart would be trailed by another pair flying 2,000 to 3,000 yards to the side, 600 yards back, and 1,000 yards above. Separation of a mile or more would allow the trailing pair to cover the lead…

textile: Modern looms: Fluid-jet looms, most recently developed of the shuttleless types, are produced and used on a much smaller scale than the two other types described above. They are of two kinds, one employing a jet of air, the other a water jet, to propel a measured…

fluidics, the technology of using the flow characteristics of liquid or gas to operate a control system. One of the newest of the control technologies, fluidics has in recent years come to compete with mechanical and electrical systems. Although fluidic principles are fairly old, it was not until

cell: Membrane fluidity: One of the triumphs of cell biology during the decade from 1965 to 1975 was the recognition of the cell membrane as a fluid collection of amphiphilic molecules. This array of proteins, sterols, and phospholipids is organized into a liquid crystal, a structure that…

coal utilization: Fluidized bed: In fluidized-bed combustion, a bed of crushed solid particles (usually six millimetres or less) is made to behave like a fluid by an airstream passing from the bottom of the bed at sufficient velocity to suspend the material in it. The bed material—usually…

food preservation: Industrial freezers: Fluidized-bed freezers are used to freeze particulate foods such as peas, cut corn, diced carrots, and strawberries. The foods are placed on a mesh conveyor belt and moved through a freezing zone in which cold air is directed upward through the mesh belt and the…

metallurgy: Roasters: Fluidized-bed roasters (see figure) have found wide acceptance because of their high capacity and efficiency. They can be used for oxidizing, sulfatizing, and volatilizing roasts. The roaster is a refractory-lined, upright cylindrical steel shell with a grate bottom through which air is blown in sufficient…

metallurgy: Roasters: Fluidized-bed roasters (see figure) have found wide acceptance because of their high capacity and efficiency. They can be used for oxidizing, sulfatizing, and volatilizing roasts. The roaster is a refractory-lined, upright cylindrical steel shell with a grate bottom through which air is blown in sufficient…

cetacean: Locomotor adaptations: Cetaceans have developed horizontal flukes that increase the propulsion area driven by the back muscles. Like fish, almost all cetaceans possess a dorsal fin that serves as a keel. The dorsal fin and flukes are composed of connective tissue, not bone. Other connective tissue, such as external ears, has…

anchor: …place by means of a fluke or pointed projection that digs into the sea bottom.

fluke, any member of the invertebrate class Trematoda (phylum Platyhelminthes), a group of parasitic flatworms that probably evolved from free-living forms millions of years ago. There are more than 10,000 species of flukes. They occur worldwide and range in size from about 5 millimetres (0.2 inch)

rimantadine, drug used to treat infections caused by influenza type A virus, the most common cause of influenza epidemics. Rimantadine is a derivative of the antiviral agent amantadine. It is composed of an alicyclic compound called adamantane that contains a methyl group (CH3) attached to an

Franconia Notch: …includes at its southern end the Flume, a narrow gorge 70 feet (21 meters) deep that extends along the flank of Mount Liberty (4,460 feet [1,359 meters]). Cannon Mountain (4,186 feet [1,276 meters]) itself, which is 5 miles (8 km) south of Franconia village, has skiing facilities and an aerial…

Flumendosa River, river that rises in the Gennargentu Mountains in southeastern Sardinia, Italy, and flows 79 miles (127 km) west and southeast, entering the Tyrrhenian Sea near Muravera. The Ente Autonomo del Flumendosa, a dam and irrigation project, was established in 1946 to develop the

Flumendosa River, river that rises in the Gennargentu Mountains in southeastern Sardinia, Italy, and flows 79 miles (127 km) west and southeast, entering the Tyrrhenian Sea near Muravera. The Ente Autonomo del Flumendosa, a dam and irrigation project, was established in 1946 to develop the

Rio de Janeiro: Education: Fluminense Federal University, across the bay in Niterói, also enjoys a good reputation, as do a few of the city’s many private nondenominational institutions—most notably, Cândido Mendes University. The very large Estácio de Sá University has branches in almost all parts of the city and…

flunitrazepam, benzodiazepine drug known for its sedative, hypnotic, and anxiolytic (antianxiety) properties and for its illicit use, most notably as a so-called date rape drug. Flunitrazepam is sold under various trade names, including Rohypnol. Because of its high potential for misuse and its

polytetrafluoroethylene (PTFE), a strong, tough, waxy, nonflammable synthetic resin produced by the polymerization of tetrafluoroethylene. Known by such trademarks as Teflon, Fluon, Hostaflon, and Polyflon, PTFE is distinguished by its slippery surface, high melting point, and resistance to attack

radiation measurement: Organic scintillators: …liquid solutions of an organic fluor (fluorescent molecule) in a solvent such as toluene, or as a plastic, in which the fluor is dissolved in a monomer that is subsequently polymerized. Frequently, a third component is added to liquid or plastic scintillators to act as a wave shifter, which absorbs…

fluorapatite, common phosphate mineral, a calcium fluoride phosphate, Ca5(PO4)3F. It occurs as minute, often green, glassy crystals in many igneous rocks, and also in magnetite deposits, high-temperature hydrothermal veins, and metamorphic rocks; it also occurs as collophane in marine deposits. For

fluorescein, organic compound of molecular formula C20H12O5 that has wide use as a synthetic colouring agent. It is prepared by heating phthalic anhydride and resorcinol over a zinc catalyst, and it crystallizes as a deep red powder with a melting point in the range of 314° to 316° C (597° to 601°

fluorescence, emission of electromagnetic radiation, usually visible light, caused by excitation of atoms in a material, which then reemit almost immediately (within about 10−8 seconds). The initial excitation is usually caused by absorption of energy from incident radiation or particles, such as

chromatography: Liquid chromatographic detectors: The fluorescence detector responds to these substances. Light bends or refracts on passing through an interface between air and a liquid or liquid solution. The degree of refraction depends on the nature of the liquid or the composition of the solution. The refractive index detector compares…

fluorescence in situ hybridization (FISH), technique that employs fluorescent probes for the detection of specific deoxyribonucleic acid (DNA) sequences in chromosomes. FISH has a much higher rate of sensitivity and specificity than other genetic diagnostic tests such as karyotyping and thus can be

fluorescence photography, process that records the glow or visible light given off by certain substances when they are irradiated by ultraviolet rays. The exclusively ultraviolet irradiation is accomplished by means of a filter at the light source; another filter, placed over the camera lens,

geology: Chemistry of the Earth: …follows: The X-ray fluorescent (XRF) spectrometer excites atoms with a primary X-ray beam and causes secondary (or fluorescent) X-rays to be emitted. Each element produces a diagnostic X-radiation, the intensity of which is measured. This intensity is proportional to the concentration of the element in the rock, and so…

dye: Fluorescent brighteners: Raw natural fibres, paper, and plastics tend to appear yellowish because of weak light absorption near 400 nm by certain peptides and natural pigments in wool and silk, by natural flavonoid dyes in cellulose, and by minor decomposition products in plastics. Although bleaching…

fluorescence in situ hybridization (FISH), technique that employs fluorescent probes for the detection of specific deoxyribonucleic acid (DNA) sequences in chromosomes. FISH has a much higher rate of sensitivity and specificity than other genetic diagnostic tests such as karyotyping and thus can be

fluorescent lamp, electric discharge lamp, cooler and more efficient than incandescent lamps, that produces light by the fluorescence of a phosphor coating. A fluorescent lamp consists of a glass tube filled with a mixture of argon and mercury vapour. Metal electrodes at each end are coated with an

microbiology: Light microscopy:

fluoroscope, instrument consisting of a surface containing chemicals called phosphors that glow when struck by X rays or gamma rays; it is used to transform images made up of invisible radiations into visible light. In a procedure called fluoroscopy, a beam of penetrating radiation is passed

syphilis test: …enzyme immunoassay (EIA); and the fluorescent treponemal antibody absorption (FTA-ABS) test. Treponemal tests are based on the detection of treponemal antibody—the antibody that attacks T. pallidum, the spirochete that causes syphilis—in the blood. In most cases, the diagnosis of syphilis is performed using both a nontreponemal and a treponemal test.

textile: Optical brightening: Optical brightening, or optical bleaches, are finishes giving the effect of great whiteness and brightness because of the way in which they reflect light. These compounds contain fluorescent colourless dyes, causing more blue light to be reflected. Changes in colour may occur as…

water fluoridation, addition of fluoride compounds to water (see fluorine) at one part per million to reduce dental caries (cavities). This practice is based on the lower rates of caries seen in areas with moderate natural fluoridation of water and on studies showing that sound teeth contain more

halogen: Oxidation: …form compounds known as halides—namely, fluorides, chlorides, bromides, iodides, and astatides. Many of the halides may be considered to be salts of the respective hydrogen halides, which are colourless gases at room temperature and atmospheric pressure and (except for hydrogen fluoride) form strong acids

fluoride deficiency, condition in which fluoride is insufficient or is not utilized properly. Fluoride is a mineral stored in teeth and bones that strengthens them by aiding in the retention of calcium. Studies have determined that the enamel of sound teeth contains more fluoride than is found in

fluorocarbon polymer, any of a number of organic polymers whose large, multiple-unit molecules consist of a chain of carbon atoms to which fluorine atoms are appended. Owing to the presence of the highly polar fluorine atoms, which form extremely strong bonds with the carbon chain and resist

fluorine (F), most reactive chemical element and the lightest member of the halogen elements, or Group 17 (Group VIIa) of the periodic table. Its chemical activity can be attributed to its extreme ability to attract electrons (it is the most electronegative element) and to the small size of its

geochronology: Accumulational processes: Fluorine dating is therefore not the simple procedure that Middleton envisioned.

fluorite, common halide mineral, calcium fluoride (CaF2), which is the principal fluorine mineral. It is usually quite pure, but as much as 20 percent yttrium or cerium may replace calcium. Fluorite occurs most commonly as a glassy, many-hued vein mineral and is often associated with lead and

fluorocarbon, compound composed of the elements carbon and fluorine; see

fluoroelastomer, any of a number of synthetic rubbers made by copolymerizing various combinations of vinylidene fluoride (CH2=CF2), hexafluoropropylene (CF2=CFCF3), chlorotrifluoroethylene (CF2=CFCl), and tetrafluoroethylene (C2=F4). These fluorinated elastomers have outstanding resistance to

fluorocarbon polymer, any of a number of organic polymers whose large, multiple-unit molecules consist of a chain of carbon atoms to which fluorine atoms are appended. Owing to the presence of the highly polar fluorine atoms, which form extremely strong bonds with the carbon chain and resist

fluoroelastomer, any of a number of synthetic rubbers made by copolymerizing various combinations of vinylidene fluoride (CH2=CF2), hexafluoropropylene (CF2=CFCF3), chlorotrifluoroethylene (CF2=CFCl), and tetrafluoroethylene (C2=F4). These fluorinated elastomers have outstanding resistance to

vinyl fluoride (H2C=CHF), a colourless, flammable, nontoxic, chemically stable gas belonging to the family of organohalogen compounds and used as the starting material in making polyvinyl fluoride, a plastic used in films for weather-resistant coatings of structural materials. Vinyl fluoride is

chemical analysis: Luminescence: …used to measure fluorescence are fluorometers, and those that are employed to measure phosphorescence are phosphorimeters. Phosphorimeters differ from fluorometers in that they monitor luminescent intensity while the exciting radiation is not striking the cell.

fluorocarbon polymer, any of a number of organic polymers whose large, multiple-unit molecules consist of a chain of carbon atoms to which fluorine atoms are appended. Owing to the presence of the highly polar fluorine atoms, which form extremely strong bonds with the carbon chain and resist

gonorrhea: Diagnosis and treatment: Thus, fluoroquinolones such as ciprofloxacin, the aminocyclitol antibiotic spectinomycin, and cephalosporins such as cefoxitin became increasingly used as alternatives for eliminating N. gonorrhoeae. Some strains of the bacteria, however, later developed resistance to fluoroquinolones, and eventually multidrug-resistant strains appeared. In the early 2000s, evidence

fluoroscope, instrument consisting of a surface containing chemicals called phosphors that glow when struck by X rays or gamma rays; it is used to transform images made up of invisible radiations into visible light. In a procedure called fluoroscopy, a beam of penetrating radiation is passed

fluoroscope: In a procedure called fluoroscopy, a beam of penetrating radiation is passed through parts of the body; transmitted radiation forms an image of the internal organs in motion on a screen for viewing. Fluoroscopes are also used for the examination of, and search for flaws in, raw and manufactured…

fluorosis, chronic intoxication with fluorine (usually combined with some other element to form a fluoride) that results in changes in the skeleton and ossification of tendons and ligaments. Exposure to fluoride in optimum amounts (about one part per million of fluoride to water) is claimed to be

fluorite, common halide mineral, calcium fluoride (CaF2), which is the principal fluorine mineral. It is usually quite pure, but as much as 20 percent yttrium or cerium may replace calcium. Fluorite occurs most commonly as a glassy, many-hued vein mineral and is often associated with lead and

halothane, nonflammable, volatile, liquid drug introduced into medicine in the 1950s and used as a general anesthetic. Halothane rapidly achieved acceptance and became the most frequently used of the potent anesthetics, despite its substantially higher cost than ether and chloroform and its

Prozac, trade name of fluoxetine hydrochloride, first of the class of antidepressant medications called selective serotonin reuptake inhibitors (SSRIs). It was introduced by Eli Lilly pharmaceutical company as a treatment for clinical depression in 1986. Prozac is also used to treat a variety of

Prozac, trade name of fluoxetine hydrochloride, first of the class of antidepressant medications called selective serotonin reuptake inhibitors (SSRIs). It was introduced by Eli Lilly pharmaceutical company as a treatment for clinical depression in 1986. Prozac is also used to treat a variety of

Tourette syndrome: …for Tourette syndrome, but pimozide, fluphenazine, clonazepam, and clonidine are also effective in reducing the frequency and intensity of tics.

Virginia Woolf: Late work: …of his biographical method; nevertheless, Flush (1933) remains both a biographical satire and a lighthearted exploration of perception, in this case a dog’s. In 1935 Woolf completed Freshwater, an absurdist drama based on the life of her great-aunt Julia Margaret Cameron. Featuring such other eminences as the poet Alfred, Lord…

gauge: Flush-pin gauges have one moving part and are used to gauge the depth of shoulders or holes. Form gauges are used to check the profile of objects; two of the most common types are radius gauges, which are packs of blades with both concave and…

Vlissingen, gemeente (municipality), southwestern Netherlands. It is situated on the southern coast of Walcheren, at the mouth of the Western Schelde (Scheldt) estuary. A medieval trading town with emphasis on herring fishing, its importance lay in its position controlling the approach to Antwerp.

tree: General features of the tree body: …grow, increasing the chance of seedling survival once the shoot begins to grow out (i.e., the internodes start to expand). This process is called flushing.

Flushing, northern section of the borough of Queens, New York City, U.S., at the head of Flushing Bay (East River). Settled in 1645 by English Nonconformists (who had probably been living at Vlissingen [Flushing], Holland), it became a Quaker centre under the leadership of John Bowne. The Flushing

flute, wind instrument in which the sound is produced by a stream of air directed against a sharp edge, upon which the air breaks up into eddies that alternate regularly above and below the edge, setting into vibration the air enclosed in the flute. In vertical, end-vibrated flutes—such as the

molding: Single curved: (3) A flute is a small groove of a semicircular, segmental, or similar section. (4) An ovolo, a convex molding, has a profile approximately a quarter-circle or quarter-ellipse. (5) A torus, a convex molding, approximates a semicircle or semiellipse. (6) A roll, or bowtell, molding is convex,…

flute, wind instrument in which the sound is produced by a stream of air directed against a sharp edge, upon which the air breaks up into eddies that alternate regularly above and below the edge, setting into vibration the air enclosed in the flute. In vertical, end-vibrated flutes—such as the

hand tool: Drilling and boring tools: …(1822) before drills with spiral flutes were proposed. A manufacturing problem—the flutes had to be hand filed—was not solved until the 1860s when the invention of a milling machine made possible the now universal twist drills.

glacial landform: Flutes: The depositional equivalent of erosional knob-and-tail structures (see above) are known as flutes. Close to the lower margin, some glaciers accumulate so much debris beneath them that they actually glide on a bed of pressurized muddy till. As basal ice flows around a pronounced…

Max Waller: …one important collection of verse, La Flute à Siebel (1887; “The Flute of Siebel”), made up of deft and clever little poems in the Parnassian style. Yet his poetry was closest in feeling to that of Heinrich Heine, Jules Laforgue, and Paul Verlaine.

wind instrument: Classification: In edge instruments (or flutes), an airstream directed against a sharp edge sets an adjoining air column within a tube into regular pulsations, producing sound. Flutes are divided into so-called true flutes and whistle flutes (also called duct flutes, fipple flutes, block flutes, or recorders). Like all aerophones, flutes…

Hendrik Terbrugghen: …as seen in his half-length The Flute Player (1621). Despite Terbrugghen’s contact with the latest Italian developments, certain archaisms from 16th-century northern painting appear in such works as his Crucifixion with the Virgin and St. John (c. 1625). Terbrugghen’s masterpiece, St. Sebastian Tended by Irene and Her Maid (1625), displays…

bel canto: …low position) and the “flute tone” (when the larynx is in a higher position), and a demand for vocal agility and clear articulation of notes and enunciation of words.

D.M. Thomas: …for the title character of The Flute-Player (1979). Like that work, his second novel, Birthstone (1980), is a fantasy. The White Hotel concerns Lisa Erdman, an early patient of Sigmund Freud; it explores her sexual hysteria and her premonitions of the 1941 Babi Yar massacre, in which she eventually dies.…

cornetfish, (family Fistulariida), any of about four species of extremely long and slim gasterosteiform fishes that constitute the genus Fistularia. They are found in tropical and temperate nearshore marine waters in the Atlantic, Pacific, and Indian oceans that are characterized by soft bottoms

Doug Flutie is an American football quarterback who won the Heisman Trophy in 1984 as the best player in college football and who had a 21-year professional football career in the United States and Canada. (Read Walter Camp’s 1903 Britannica essay on inventing American football.) Flutie was a

Doug Flutie is an American football quarterback who won the Heisman Trophy in 1984 as the best player in college football and who had a 21-year professional football career in the United States and Canada. (Read Walter Camp’s 1903 Britannica essay on inventing American football.) Flutie was a

fluting and reeding, in architectural decoration, surfaces worked into a regular series of (vertical) concave grooves or convex ridges, frequently used on columns. In Classical architecture fluting and reeding are used in the columns of all the orders except the Tuscan. In the Doric order there are

flutter and wow, in sound reproduction, waver in a reproduced tone or group of tones that is caused by irregularities in turntable or tape drive speed during recording, duplication, or reproduction. Low-frequency irregularities (as one per revolution of a turntable, referred to as “once arounds”)

backstroke: …head and uses an up-and-down flutter kick. The backstroke is a competition stroke, but it is also used in recreational swimming as a rest from other strokes, frequently with minimal arm motion and only enough kick to maintain forward motion. It is the third fastest of the four main strokes…

moulin: …same as that of a fluvial pothole, the moulin pothole can be distinguished by its location. Moulin potholes have been found on hilltops and steep slopes and may occur scattered over a valley floor, without the kind of alignment that occurs when streams are involved. A moulin is noted for…

fluvial process, the physical interaction of flowing water and the natural channels of rivers and streams. Such processes play an essential and conspicuous role in the denudation of land surfaces and the transport of rock detritus from higher to lower levels. Over much of the world the erosion of

cave: Fluviokarst: In this type of karst landscape, the pattern of surface stream channels and stream valleys is still in evidence, though much of the drainage may be underground. Tributary surface streams may sink underground, and there may be streambeds that carry water only during seasons…

Fluvisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). Fluvisols are found typically on level topography that is flooded periodically by surface waters or rising groundwater, as in river floodplains and deltas and in coastal lowlands. They

Jan Bruegel the Elder was a Flemish painter known for his still lifes of flowers and for his landscapes. The second son of Pieter Bruegel the Elder, born just before his father’s death, he was reared by a grandmother and learned his art in Antwerp. In his youth he went to Italy, where he painted

Jan Bruegel the Elder was a Flemish painter known for his still lifes of flowers and for his landscapes. The second son of Pieter Bruegel the Elder, born just before his father’s death, he was reared by a grandmother and learned his art in Antwerp. In his youth he went to Italy, where he painted

Jan Bruegel the Elder was a Flemish painter known for his still lifes of flowers and for his landscapes. The second son of Pieter Bruegel the Elder, born just before his father’s death, he was reared by a grandmother and learned his art in Antwerp. In his youth he went to Italy, where he painted

enamelwork: Materials and techniques: …this substance is known as flux or frit—or, in France, fondant. The degree of hardness of the flux depends on the proportions of the components in the mix. Enamels are termed hard when the temperature required to fuse them is very high; the harder the enamel is, the better it…

nervous system: Localized potential: By permitting a flux of Na+ into the cell, the opening of ion channels slightly depolarizes the membrane. The extent to which the membrane is depolarized depends upon the extent to which the sodium channels are activated, and this in turn depends upon the strength and duration of…

principles of physical science: Gauss’s theorem: …elementary area is E, the flux through the element is defined as the product of the magnitude dS and the component of E normal to the element—i.e., the scalar product E · dS. A charge q at the centre of a sphere of radius r generates a field ε =…

flux, in metallurgy, any substance introduced in the smelting of ores to promote fluidity and to remove objectionable impurities in the form of slag. Limestone is commonly used for this purpose in smelting iron ores. Other materials used as fluxes are silica, dolomite, lime, borax, and fluorite. In

electromagnetism: Faraday’s law of induction: …found that (1) a changing magnetic field in a circuit induces an electromotive force in the circuit; and (2) the magnitude of the electromotive force equals the rate at which the flux of the magnetic field through the circuit changes. The flux is a measure of how much field penetrates…