VLT Interferometer (VLTI)
Fr.: interféromètre VLTI
An interferometer using a combination of the four 8.2 m VLT telescopes with the assistance of one or more of the the four 1.8 m Auxiliary Telescopes in order to achieve a very high spatial resolution. The system works in the visible and near- and mid-infrared wavelengths.
M.L. vocabularium "a list of words," from L. vocabulum "word, name, noun," from vocare "to name, call;" cognate with Pers. vâž, → word.
Vâžgân, from vâž, → word, + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, from Proto-Iranian *kāna-ka-.
Fr.: corde vocale
The sharp edge of a fold of mucous membrane stretching along either wall of the larynx from the angle between the laminae of the thyroid cartilage to the vocal process of the arytenoid cartilage. Vibrations of these cords are used in voice production (The American Heritage).
Fr.: théorème de Russell-Vogt
The internal structure and all observable characteristics of a star (such as luminosity and temperature) are determined uniquely by its mass, chemical composition, and age. Same as → Russell-Vogt theorem.
Named after the German astronomer Heinrich Vogt (1890-1968) and the American astronomer Henry Norris Russell (1877-1957); → theorem.
Sounds made when speaking or singing.
M.E., from O.Fr. voiz, from L. vox "voice, sound, utterance, cry, call, speech, sentence, word," related to vocare "to call;" akin to Pers. âvâz "voice," as below.
Âvaz "voice, sound, song," related to âvâ "voice, sound, song" (both prefixed forms), bâng "voice, sound, clamour" (Mid.Pers. vâng), vâžé "word," variants vâj-, vâk-, vâ-, vâz-, vât-; Av. vacah- "word," vaocanghê "to decalre" (by means of speech), from vac- "to speak, say;" cf. Skt. vakti "speaks, says," vacas- "word;" Gk. epos "word;" L. vox "voice;" PIE base *wek- "to speak."
1) An empty space; a gap or opening; emptiness.
M.E. voide, from O.Fr. voide "empty, vast, wide, hollow," from L. vocivus "unoccupied, vacant," related to vacuus "empty," → vacuum.
Tohi "empty" (variants in dialects Tabari tisâ, Saraxsi, Lâsgardi, Sangesari tusâ, Aftari tussâ); Mid.Pers. tuhig; Av. taoš- "to become empty," pres. tusa-, caus. taošaya-, tusən "they lose their posture;" cf. Skt. tuccha-, tucchya- "empty;" L. tesqua, tesca "deserted place;" Rus. tošcij "hollow;" PIE base *teus- "to empty."
Fr.: effet Vogt
Double refraction occurring when a strong → magnetic field is applied to a vapor through which light is passing perpendicular to the field.
Named after Woldemar Voigt (1850-1919), a German physicist (1908, Magneto- und Elektro-optik, B. G. Teubner, Leipzig); → effect.
Fr.: profil de Voigt
A spectral profile in which a → spectral line is broadened by two types of mechanisms, one of which alone would produce a & rarr; Gaussian profile (usually, as a result of the → Doppler broadening), and the other would produce a → Lorentzian profile.
After Woldemar Voigt (1850-1919), a German physicist; → profile.
Mâhi-ye Parandé (#)
Fr.: Poisson volant
The Flying Fish. A constellation in the southern hemisphere at 7h 40m right ascension, -70° declination. Originally called Piscis Volans, and invented by Johann Bayer (Uranometria, published in 1603). Abbreviation: Vol; Genitive: Volantis.
L. Volans "flying," from volare "to fly."
Mâhi-ye Parandé, from mâhi "fish" (Mid.Pers. mâhik; Av. masya-; cf. Skt. matsya-; Pali maccha-) + parandé "flying, flier," from paridan "to fly" (Mid./Mod.Pers. par(r) "feather, wing," Av. parəna- "feather, wing;" cp. Skt. parna "feather," E. fern; PIE *porno- "feather").
A substance that vaporizes at relatively low temperatures (e.g. H2O, CO2, CO, CH4, NH3, and so forth). The opposite of volatile is → refractory.
M.E., from M.Fr. volatile, from L. volatilis "fleeting, transitory, flying," from p.p. stem of volare "to fly," of unknown origin.
Parrâ "flying," from paridan "to fly in the air," → Volans.
Fr.: élément volatile
In → planetary science, any of a group of → chemical elements and → chemical compounds with relatively low → boiling points that are associated with a planet's or moon's → crust and/or → atmosphere. For example, H, He, C, N, O are underabundant (relative to the solar → photospheric values) in all types of → meteorites, including the C1 → carbonaceous chondrites. Any heating of the meteorite parent body subsequent to its formation would tend to drive the volatile elements out of the rock, whence it sublimated into → interplanetary medium.
Of or relating to a volcano. Characterized by volcanoes.
Fr.: éruption volcanique
The explosive ejection of superheated matter from a → volcano.
volcanic explosivity index (VEI)
dišan-e oskaftandegi-ye âtašfešâni
Fr.: indice d'explosivité volcanique
A logarithmic scale, ranging from 1 to 8, used to measure the intensity of volcano eruptions. The VEI is based on several factors: the degree of fragmentation of the volcanic products released by the eruption, the amounts of sulfur-rich gases that form stratospheric aerosols, the volume of the eruptions, their duration, and the height is reached. The largest eruptions (8) produce an amount of bulk volume of ejected → tephra of ~ 1,000 km3.
dudkaš-e âtašfešâni (#)
Fr.: cheminée volcanique
From It. vulcano, from L. Vulcanus, → Vulcan.
Âtašfešân, literally "fire disperser, dispersing fire," from âtaš, → fire, + fešân contraction of afšân, from afšândan "to spread, scatter," Mid.Pers. afšân "to spread, to scatter;" ultimately from Proto-Ir. *apašan-, from root *šan- "to shake" (Cheung 2007).
The SI unit of potential difference, defined as the difference of potentials across the ends of a conductor in which a power 1 watt is liberated when a current of 1 ampere flows through it.
In honor of the Italian scientist Alessandro Volta (1745-1827), known for his pioneering work in electricity and the invention of the first battery.
Fr.: voltage, tension
The electric potential difference expressed in volts.
From → volt.
Of, relating to electricity or electric currents, especially when produced by chemical action, as in a cell. → photovoltaic detector.
Alessandro Volta (1745-1827), Italian physicist, known for his pioneering work in electricity.
The amount of space occupied by a three-dimensional object or region of space, expressed in cubic units.
M.E. volum(e), from O.Fr. volume, from L. volumen (genitive voluminis) "roll (as of a manuscript), coil, wreath," from volvere "to turn around, roll."
Gonj "volume," gonjidan "to be contained or held; to hold;" gonjâyeš "capacity, holding, containing;" Mid.Pers. winj- "to be contained;" Proto-Iranian *uiac-/*uic-; cf. Skt. vyac- "to contain, encompass," vyás- "extent, content, extension;" L. uincire "to bind."