theremin, electronic musical instrument invented in 1920 in the Soviet Union by Leon Theremin (also called Lev Termen). It consists of a box with radio tubes producing oscillations at two sound-wave frequencies above the range of hearing; together, they produce a lower audible frequency equal to

theremin, electronic musical instrument invented in 1920 in the Soviet Union by Leon Theremin (also called Lev Termen). It consists of a box with radio tubes producing oscillations at two sound-wave frequencies above the range of hearing; together, they produce a lower audible frequency equal to

Maria Theresa was the archduchess of Austria and queen of Hungary and Bohemia (1740–80), wife and empress of the Holy Roman emperor Francis I (reigned 1745–65), and mother of the Holy Roman emperor Joseph II (reigned 1765–90). Upon her accession, the War of the Austrian Succession (1740–48)

French literature: Politics subordinate to other concerns: Mauriac, Bernanos, and others: Thérèse Desqueyroux) and Noeud de vipères (1932; The Knot of Vipers), blind to the romance and thrill of the modern, deployed the traditional form of the French psychological novel to evoke the banal desolation of characters deprived of God’s grace and stranded in a desert…

St. Thérèse of Lisieux ; canonized May 17, 1925; feast day October 1) was a Carmelite nun whose service to her Roman Catholic order, although outwardly unremarkable, was later recognized for its exemplary spiritual accomplishments. She was named a doctor of the church by Pope John Paul II in 1997.

Thérèse Raquin, novel by Émile Zola, first published serially as Un Mariage d’amour in 1867 and published in book form with the present title in the same year. Believing that an author must simply establish his characters in their particular environment and then observe and record their actions as

Theresienstadt, town in northern Bohemia (now in the Czech Republic), founded in 1780 and used from 1941 to 1945 by Nazi Germany as a walled ghetto, or concentration camp, and as a transit camp for western Jews en route to Auschwitz and other extermination camps. Reinhard Heydrich, the head of the

stiletto fly, (family Therevidae), any of about 1,600 species of insects in the fly order, Diptera. Adults are hairy or bristly, with slender bodies. They are usually found in open areas, such as pastures. The larvae occur in soil and decaying matter, and both adults and larvae are predatory. The

Teresina, city, capital of Piauí estado (state), northeastern Brazil. The city lies along the Parnaíba River (there bridged to Timon in Maranhão state), 220 miles (354 km) upstream from the Atlantic port of Parnaíba. Founded in 1852 as the new capital of Piauí, it was originally named Therezina for

Teresópolis, city, central Rio de Janeiro estado (state), southwestern Brazil. It lies in the Órgãos Mountains at 2,959 feet (902 metres) above sea level, about 35 miles (56 km) north-northeast of the city of Rio de Janeiro. Named for the Brazilian empress Teresa Cristina in 1890 and originally

mammal: Classification: Subclass Theria (live-bearing mammals) Metatheria (marsupials) More than 330 species in 7 orders. Order Diprotodontia (kangaroos, koalas, wombats, possums, and kin)

classification of religions: Morphological: …stage of nature religions is therianthropic polytheism, in which the deities are normally of mixed animal and human composition. The highest stage of nature religion is anthropomorphic polytheism, in which the deities appear in human form but have superhuman powers. These religions have some ethical elements, but their mythology portrays…

Yves Thériault was one of the most prolific writers in Canada, with some 1,300 radio and television scripts and some 50 books to his credit. He was hailed as a literary genius after the publication of Agaguk (1958), a poignant tale about an Inuit (Eskimo) family faced with the white man’s code of

comb-footed spider, any member of the spider family Theridiidae (order Araneida). The more than 1,000 species of comb-footed spiders are distributed around the world, and they include the black widow. The webs of theridiids consist of an irregular network of threads from which the spider often

ray spider, any spider of the family Theridiosomatidae (order Araneida), known for their conelike webs. Most ray spiders are less than 3 mm (0.125 inch) in body length and are usually found near streams or in damp areas. The strands of the ray spider’s web extend outward in raylike groups of three

myth: The alter ego, or life index: …of the latter relationship is nagualism, a phenomenon found among the aboriginals of Guatemala and Honduras in Central America. Nagualism is the belief that there exists a nagual—an object or, more often, an animal—that stands in a parallel relationship to a person. If the nagual suffers harm or death, the…

mask: General characteristics: …those with animal characteristics as theriomorphic. In some instances the mask form is a replication of natural features or is quite realistic, and in other instances it is an abstraction. Masks usually represent supernatural beings, ancestors, and fanciful or imagined figures, and they can also be portraits. The localization of…

religious symbolism and iconography: Theriomorphic, or zoomorphic, motifs: …representation of the divine (theriomorphism, or zoomorphism) is characteristic of polytheism. It has been maintained in Hinduism, to some extent in Buddhism, and occasionally in Christianity. Besides the theriomorphic (animal-form) representations of the holy (e.g., the ancient Egyptian gods and animals that are symbols of the divine or the…

therizinosaur, group of theropod dinosaurs that lived during the Late Cretaceous (roughly 100 million to 66 million years ago) in Asia and North America and were characterized by their relatively small skulls, leaf-shaped teeth, and extended fingers with extremely long and robust claws.

British thermal unit: …use a larger unit, the therm, defined as 100,000 BTU, as a measure of gas consumption.

Diocletian window, semicircular window or opening divided into three compartments by two vertical mullions. Diocletian windows were named for those windows found in the Thermae, or Baths, of Diocletian (now the church of Santa Maria degli Angeli) in Rome. The variant name, thermal window, also

thermae, complex of rooms designed for public bathing, relaxation, and social activity that was developed to a high degree of sophistication by the ancient Romans. Although public baths are known to have existed in early Egyptian palaces, remains are too fragmentary to permit complete analysis of

Baths of Caracalla, public baths in ancient Rome begun by the emperor Septimius Severus in ad 206 and completed by his son the emperor Caracalla in 216. Among Rome’s most beautiful and luxurious baths, designed to accommodate about 1,600 bathers, the Baths of Caracalla continued in use until the

Termini Imerese, town, northern Sicily, Italy, on the Golfo (gulf) di Termini Imerese (an inlet of the Tyrrhenian Sea), southeast of Palermo city. It was possibly a Phoenician seaport or trading station, and its well-known thermal saline springs were praised by the 6th–5th-century bce Greek poet

Gulf of Thérmai, large gulf of the Aegean Sea in northeastern Greece between Thessaly (Modern Greek: Thessalía), Macedonia (Makedonía), and the Chalcidice (Chalkidikí) peninsula. It is up to 60 miles (100 km) long northwest-southeast and about 40 miles (65 km) wide at its broadest point, at the

Gulf of Thérmai, large gulf of the Aegean Sea in northeastern Greece between Thessaly (Modern Greek: Thessalía), Macedonia (Makedonía), and the Chalcidice (Chalkidikí) peninsula. It is up to 60 miles (100 km) long northwest-southeast and about 40 miles (65 km) wide at its broadest point, at the

Gulf of Thérmai, large gulf of the Aegean Sea in northeastern Greece between Thessaly (Modern Greek: Thessalía), Macedonia (Makedonía), and the Chalcidice (Chalkidikí) peninsula. It is up to 60 miles (100 km) long northwest-southeast and about 40 miles (65 km) wide at its broadest point, at the

thermal, current of air rising from a locally hot patch of ground. See updraft and

chemical analysis: Thermal analysis: During thermal analysis heat is added to an analyte while some property of the analyte is measured. Often the temperature of the sample is monitored during the addition of heat. The manner in which the temperature changes is compared to the way in…

ammeter: In the thermal (or hot-wire) ammeter, used primarily to measure AC with accuracies of 0.5 to 3 percent, the measured current heats a piece of wire, and the current is indicated by how much the wire expands. Digital ammeters, with no moving parts, use a circuit such…

chemical analysis: Thermal analysis: During thermal analysis heat is added to an analyte while some property of the analyte is measured. Often the temperature of the sample is monitored during the addition of heat. The manner in which the temperature changes is compared to the way in…

atmosphere: Distribution of heat from the Sun: The primary driving force for the horizontal structure of Earth’s atmosphere is the amount and distribution of solar radiation that comes in contact with the planet. Earth’s orbit around the Sun is an ellipse, with a perihelion (closest approach)…

breeder reactor: Thermal breeder reactors: Another type of breeder, the thermal breeder reactor, employs thorium-232 as its basic fuel, or fertile material. It converts this isotope into fissionable uranium-233, which is capable of creating a chain reaction. In the thermal breeder, whose technology is much simpler than…

heat capacity, ratio of heat absorbed by a material to the temperature change. It is usually expressed as calories per degree in terms of the actual amount of material being considered, most commonly a mole (the molecular weight in grams). The heat capacity in calories per gram is called specific

thermal conduction, transfer of energy (heat) arising from temperature differences between adjacent parts of a body. Thermal conductivity is attributed to the exchange of energy between adjacent molecules and electrons in the conducting medium. The rate of heat flow in a rod of material is

thermal conductivity, the ability of a substance to conduct heat or move heat from one location to another without the movement of the material conducting the heat. Thermal conductivity is measured in watts per meter kelvin (W/mK). For example, solid aluminum has a thermal conductivity of 237 W/mK

mountain: Tectonic processes that destroy elevated terrains: Similarly, the cooling and associated thermal contraction of the outer part of the Earth leads to a reduction of the average height of a mountain belt.

cracking: The first thermal cracking process for breaking up large nonvolatile hydrocarbons into gasoline came into use in 1913; it was invented by William Merriam Burton, a chemist who worked for the Standard Oil Company (Indiana), which later became the Amoco Corporation. Various improvements to thermal cracking were…

spectroscopy: Infrared instrumentation: Thermal detection of infrared radiation is based on the conversion of a temperature change, resulting from such radiation falling on a suitable material, into a measurable signal. A Golay detector employs the reflection of light from a thermally distortable reflecting film onto a photoelectric cell,…

gas: Diffusion and thermal diffusion: Both of these properties present difficulties for the simple mean free path version of kinetic theory. In the case of diffusion it must be argued that collisions of the molecules of species 1 with other species 1 molecules do not inhibit the interdiffusion…

industrial glass: Thermal expansion: …shock is known as the thermal endurance of a glass; it is inversely related to the thermal-expansion coefficient and the thickness of the piece. The thermal expansion coefficients of various oxide glasses are shown in the table of properties of oxide glasses.

thermal energy, internal energy present in a system in a state of thermodynamic equilibrium by virtue of its temperature. Thermal energy cannot be converted to useful work as easily as the energy of systems that are not in states of thermodynamic equilibrium. A flowing fluid or a moving solid, for

thermodynamics: …two systems are each in thermal equilibrium with a third system, the first two systems are in thermal equilibrium with each other. This property makes it meaningful to use thermometers as the “third system” and to define a temperature scale. The first law of thermodynamics, or the law of conservation…

thermal expansion, the general increase in the volume of a material as its temperature is increased. It is usually expressed as a fractional change in length or volume per unit temperature change; a linear expansion coefficient is usually employed in describing the expansion of a solid, while a

combustion: Thermal explosions: Thermal explosion theory is based on the idea that progressive heating raises the rate at which heat is released by the reaction until it exceeds the rate of heat loss from the area. At a given composition of the mixture and a given…

gas meter: In thermal-type gas meters a heater (such as an electrical heating coil) is placed in the gas stream, and thermometers are installed on its upstream and downstream sides. Gas flow is measured in relation to either the temperature rise of the gas stream or the amount…

metamorphic rock: Temperature: …in Earth, known as the geothermal gradient, is the increase in temperature per unit distance of depth; it is given by the tangent to the local geotherm. The magnitude of the geothermal gradient thus varies with the shape of the geotherm. In regions with high surface heat flow, such as…

thermoreception: Thermoreceptors and pain reception: …spatially interlaced; this so-called “thermal grill illusion” mimics the burning sensation associated with painful cold (usually reported at temperatures below 15 °C [59 °F]). The thermal grill demonstrates that there is a central neural mechanism for the cold inhibition of pain. The cold bars in the grill (below 20…

wastewater treatment: Digestion: …two-stage anaerobic digestion process is thermal hydrolysis, or the breaking down of the large molecules by heat. This is done in a separate step before digestion. In a typical case, the process begins with a sludge that has been dewatered to a DS content of some 15 percent. The sludge…

mass spectrometry: Thermal ionization: Atoms with low ionization potentials can be ionized by contact with the heated surface of a metal, generally a filament, having a high work function (the energy required to remove an electron from its surface) in a process called thermal, or surface, ionization.…

Saha equation, mathematical relationship between the observed spectra of stars and their temperatures. The equation was stated first in 1920 by the Indian astrophysicist Meghnad N. Saha. It expresses how the state of ionization of any particular element in a star changes with varying temperatures

dating: Technical advances: …the use of highly sensitive thermal ionization mass spectrometers is replacing the counting techniques employed in some disequilibrium dating. Not only has this led to a reduction in sample size and measurement errors, but it also has permitted a whole new range of problems to be investigated. Certain parent-daughter isotopes…

thermocouple, a temperature-measuring device consisting of two wires of different metals joined at each end. One junction is placed where the temperature is to be measured, and the other is kept at a constant lower temperature. A measuring instrument is connected in the circuit. The temperature

climate change: Thermal maxima: Many parts of the globe experienced higher temperatures than today some time during the early to mid-Holocene. In some cases the increased temperatures were accompanied by decreased moisture availability. Although the thermal maximum has been referred to in North America and elsewhere as…

climate change: Thermal maxima: Many parts of the globe experienced higher temperatures than today some time during the early to mid-Holocene. In some cases the increased temperatures were accompanied by decreased moisture availability. Although the thermal maximum has been referred to in North America and elsewhere as…

natural gas: The biological stage: Often significant amounts of thermal methane gas are generated along with the oil. Below 2,900 metres (9,500 feet), primarily wet gas (gas containing liquid hydrocarbons) is formed.

asteroid: Size and albedo: By using a so-called thermal model to balance the measured intensity of infrared radiation with that of radiation at visual wavelengths, investigators are able to derive the diameter of the asteroid. Other remote-sensing techniques—for example, polarimetry, radar, and adaptive optics (techniques for minimizing the distorting effects of Earth’s atmosphere)—also…

weather modification: Changes in the radiation balance near the ground: …is known as the “thermal mountain effect.”

thermal neutron, any free neutron (one that is not bound within an atomic nucleus) that has an average energy of motion (kinetic energy) corresponding to the average energy of the particles of the ambient materials. Relatively slow and of low energy, thermal neutrons exhibit properties, such as

Harry Nyquist: …explanation of the unexpectedly strong thermal noise studied by J.B. Johnson. The understanding of noise is of critical importance for communications systems. Thermal noise is sometimes called Johnson noise or Nyquist noise because of their pioneering work in this field.

integrated circuit: Chemical methods: …are electrodeposition (or electroplating) and thermal oxidation. In the former the substrate is given an electrically conducting coating and placed in a liquid solution (electrolyte) containing metal ions, such as gold, copper, or nickel. A wide range of film thicknesses can be built. In thermal oxidation the substrate is heated…

thermoperiodicity, the growth or flowering responses of plants to alternation of warm and cool periods. Daily temperature fluctuations produce dramatic effects on the growth or flowering of most plants. The lack of lower night temperatures frequently results in poor growth, as can be observed in

whirlwind: Dust devils: …leads to the formation of thermal plumes (large parcels of hot air rising from the surface). A dust devil draws on this stored energy to develop and then maintain itself. A light wind is required to start rotation in the rising plume. When dissipative forces, such as surface friction and…

river: Environmental problems attendant on river use: Such heated water can alter the existing ecology, sometimes sufficiently to drive out or kill desirable species of fish. It also may cause rapid depletion of the oxygen supply by promoting algal blooms.

Brazil: Power: …has given lower priority to thermal power generation because of the poor quality of Brazilian coal. The opening of a gas pipeline from Bolivia in 1999 has led to a program for construction of gas-fired thermoelectric generating plants, chiefly in the Southeast. The opening of a Bolivia-Brazil natural gas pipeline…

water supply system: Thermal processes: Distillation, a thermal process that includes heating, evaporation, and condensation, is the oldest and most widely used of desalination technologies. Modern methods for the distillation of large quantities of salt water rely on the fact that the boiling temperature of water is lowered…

food preservation: Thermal processing: Thermal processing is defined as the combination of temperature and time required to eliminate a desired number of microorganisms from a food product.

thermal radiation, process by which energy, in the form of electromagnetic radiation, is emitted by a heated surface in all directions and travels directly to its point of absorption at the speed of light; thermal radiation does not require an intervening medium to carry it. Thermal radiation

asteroid: Size and albedo: …solar system) is that of thermal radiometry. That technique exploits the fact that the infrared radiation (heat) emitted by an asteroid must balance the solar radiation it absorbs. By using a so-called thermal model to balance the measured intensity of infrared radiation with that of radiation at visual wavelengths, investigators…

petroleum refining: Naphtha reforming: The initial process, thermal reforming, was developed in the late 1920s. Thermal reforming employed temperatures of 510–565 °C (950–1,050 °F) at moderate pressures—about 40 bars (4 MPa), or 600 psi—to obtain gasolines (petrols) with octane numbers of 70 to 80 from heavy naphthas with octane numbers of less…

thermodynamics: The second law of thermodynamics: …essential point is that the heat reservoir is assumed to have a well-defined temperature that does not change as a result of the process being considered.

thermistor, electrical-resistance element made of a semiconducting material consisting of a mixture of oxides of manganese and nickel; its resistance varies with temperature. Thermistors (temperature-sensitive, or thermal, resistors) are used as temperature-measuring devices and in electrical

refractory: Properties: …also must be resistant to thermal shock. Thermal shock occurs when an object is rapidly cooled from high temperature. The surface layers contract against the inner layers, leading to the development of tensile stress and the propagation of cracks. Ceramics, in spite of their well-known brittleness, can be made resistant…

hot spring, spring with water at temperatures substantially higher than the air temperature of the surrounding region. Most hot springs discharge groundwater that is heated by shallow intrusions of magma (molten rock) in volcanic areas. Some thermal springs, however, are not related to volcanic

radiation: Surface effects: Yet another mechanism is prompt thermal sputtering, in which energized atoms in thermal spikes created close to the surface escape through the surface before annealing occurs. Certain materials (e.g., crystalline alkali halides) are prone to electronic sputtering, in which energy associated with electronic excitations induced by the incident ion is…

mechanics of solids: Thermal strains: Temperature change can also cause strain. In an isotropic material the thermally induced extensional strains are equal in all directions, and there are no shear strains. In the simplest cases, these thermal strains can be treated as being linear in the temperature change…

gas: Thermal transpiration: Suppose that two containers of the same gas but at different temperatures are connected by a tiny hole and that the gas is brought to a steady state. If the hole is small enough and the gas density is low enough that only…

heat-treating, changing the properties of materials such as metals or glass by processes involving heating. It is used to harden, soften, or modify other properties of materials that have different crystal structures at low and high temperatures. The type of transformation depends on the

Diocletian window, semicircular window or opening divided into three compartments by two vertical mullions. Diocletian windows were named for those windows found in the Thermae, or Baths, of Diocletian (now the church of Santa Maria degli Angeli) in Rome. The variant name, thermal window, also

chromatography: Gas chromatographic detectors: Thermal-conductivity detectors compare the heat-conducting ability of the exit gas stream to that of a reference stream of pure carrier gas. To accomplish this, the gas streams are passed over heated filaments in thermal-conductivity cells. Measured changes in filament resistance of the cells reflect temperature…

thermal-heat recovery, use of heat energy that is released from some industrial processes and that would otherwise dissipate into the immediate environment unused. Given the prevalence of heat-generating processes in energy systems, such as those found in household heating and cooling systems and

gliding: …basic method of soaring, called thermaling, is to find and use rising currents of warm air, such as those above a sunlit field of ripened grain, to lift the glider. Thermals can rise very rapidly, which allows the sailplane, if deftly piloted, to attain substantial increases in altitude. Slope soaring…

Peter Zumthor: A commission to design the Therme Vals (1996) in Vals, Switzerland, presented Zumthor with a prime opportunity to create a series of varied spatial experiences. The structure, appearing like an enormous geometric rock carved within the hillside, is made from local quartz and concrete. The building’s entry is a dark…

thermocouple, a temperature-measuring device consisting of two wires of different metals joined at each end. One junction is placed where the temperature is to be measured, and the other is kept at a constant lower temperature. A measuring instrument is connected in the circuit. The temperature

Gustav Tammann: …developed a method known as thermic analysis for determining the chemical composition of a compound from its cooling curve, which enabled him to explain systems of mixed crystals. Tammann conducted much research on the mechanical properties of metals during coldworking and found that changes in such properties resulted from a…

human nutrition: BMR and REE: energy balance: This phenomenon, known as the thermic effect of food (or diet-induced thermogenesis), accounts for about 10 percent of daily energy expenditure, varying somewhat with the composition of the diet and prior dietary practices. Adaptive thermogenesis, another small but important component of energy expenditure, reflects alterations in metabolism due to changes…

Elsie de Wolfe: …Frohman’s production of Victorien Sardou’s Thermidor (1891) and toured with the production for two years. In 1894 she became a regular member of Frohman’s company. In 1901 she formed her own company and presented Clyde Fitch’s The Way of the World on Broadway and in a two-year tour. She retired…

Thermidor, the name given during the French Revolution to the eleventh month of the year in the republican calendar. The month fell in the hottest season of the year, beginning on July 19 or 20 and ending on August 18 or 19, according to the year. As in all the other months of the republican

Thermidorian Reaction, in the French Revolution, the parliamentary revolt initiated on 9 Thermidor, year II (July 27, 1794), which resulted in the fall of Maximilien Robespierre and the collapse of revolutionary fervour and the Reign of Terror in France. By June 1794 France had become fully weary

thermionic emission, discharge of electrons from heated materials, widely used as a source of electrons in conventional electron tubes (e.g., television picture tubes) in the fields of electronics and communications. The phenomenon was first observed (1883) by Thomas A. Edison as a passage of

thermionic power converter, any of a class of devices that convert heat directly into electricity using thermionic emission rather than first changing it to some other form of energy. A thermionic power converter has two electrodes. One of these is raised to a sufficiently high temperature to

thermionic power converter, any of a class of devices that convert heat directly into electricity using thermionic emission rather than first changing it to some other form of energy. A thermionic power converter has two electrodes. One of these is raised to a sufficiently high temperature to

thermionic power converter, any of a class of devices that convert heat directly into electricity using thermionic emission rather than first changing it to some other form of energy. A thermionic power converter has two electrodes. One of these is raised to a sufficiently high temperature to

electronics: The vacuum tube era: Coolidge and Fleming’s thermionic valve (a two-electrode vacuum tube) for use in radio receivers. The detection of a radio signal, which is a very high-frequency alternating current (AC), requires that the signal be rectified; i.e., the alternating current must be converted into a direct current (DC) by a…

electronics: The vacuum tube era: Coolidge and Fleming’s thermionic valve (a two-electrode vacuum tube) for use in radio receivers. The detection of a radio signal, which is a very high-frequency alternating current (AC), requires that the signal be rectified; i.e., the alternating current must be converted into a direct current (DC) by a…

electronic work function: …a heated platinum filament (thermionic work function) differs slightly from that required to eject an electron from platinum that is struck by light (photoelectric work function). Typical values for metals range from two to five electron volts.

thermistor, electrical-resistance element made of a semiconducting material consisting of a mixture of oxides of manganese and nickel; its resistance varies with temperature. Thermistors (temperature-sensitive, or thermal, resistors) are used as temperature-measuring devices and in electrical

Thermit, powdered mixture used in incendiary bombs, in the reduction of metals from their oxides, and as a source of heat in welding iron and steel and in foundry work. The powder consists of aluminum and the oxide of a metal such as iron. When ignited or heated, it gives off an enormous amount of

Thermit, powdered mixture used in incendiary bombs, in the reduction of metals from their oxides, and as a source of heat in welding iron and steel and in foundry work. The powder consists of aluminum and the oxide of a metal such as iron. When ignited or heated, it gives off an enormous amount of

firebrat, (Thermobia domestica), stout-bodied quick-moving wingless insect. The firebrat is worldwide in distribution and is commonly found indoors, typically lingering in warm locations, such as near fireplaces, furnaces, and water heaters. It feeds on starches and thus can cause damage to books,