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equalizer hamugsâz Fr.: équaliseur Electronics: A device, usually an electric network, designed to correct for unequal attenuation of phase shift in the transmission of signals. Agent noun from → equalize. |
equals sign nešâne-ye hamug Fr.: signe égal A mathematical symbol (=) that indicates equality of two expressions on each side of the sign. Same as → equality sign. The equals sign appears for the first time in Robert Recorde's book The Whetstone of Witte published in 1557. He was a Welsh physician and mathematician. |
equant falak-e mo'adel (al-masir) (#) Fr.: équant In Ptolemy's → geocentric system, an imaginary point near the center of the → deferent but at a position opposite to that of the Earth from the center of the deferent. Ptolemy further supposed that the distance from the Earth to the center of the deferent was equal to the distance from the center of the deferent to the equant. He also claimed that the planet's deferent and the → epicycle described uniform circular motion around the equant. L. aequant-, s. of aequans, pr.p. of aequare "to make equal." Falak-e mo'adel (al-masir), literally "the sphere that equalizes (the path)," from Ar. falak "celestial orbit; sphere; heaven," from Babylonian pulluku + mo'adel "equalizing" (+ masir "path"). |
equate hamugidan Fr.: mettre en équation To put in the form of an equation; to state the equality of or between. L. æquatus, p.p. of æquare "to make equal," from æquus "equal, level, even." Infinitive form of hamug, → equal. |
equation hamugeš Fr.: équation A statement asserting the equality of two numbers or two expressions. It consists of two parts, called sides or members of the equation, separated by the Same as → equality sign. From L. æquation- "an equalizing," noun of → equate. Verbal noun of hamugidan, → equate. |
equation of motion hamugeš-e jonbeš Fr.: équation de mouvement 1) Any equation that describes the motion of objects, i.e., variation of
velocity, distance covered, acceleration, etc., as a function of time;
e.g., V = V_{0} +
at, S = Vt + (1/2)at^{2}. |
equation of state hamugeš-e hâlat Fr.: équation d'état In physics and thermodynamics, the equation that describes the relationship between pressure, density, and temperature, e.g. → ideal gas law, → van der Waals equation, → polytropic process, → virial equation of state. |
equation of state parameter pârâmun-e hamugeš-e hâlat Fr.: paramètre de l'équation d'état In cosmology, a → dimensionless parameter introduced by the → equation of state representing the ratio of the pressure to the energy density of a fluid, such as the → dark energy: w = p/ρ. The → deceleration or → acceleration of an → expanding Universe depends on this parameter (→ accelerating Universe). A number of numerical values of this parameter are as follows: for the → cosmological constant: w = -1, for → non-relativistic matter (present-day → baryons): w = 0, and for → relativistic matter (photons, neutrinos): w = +1/3. Together with Ω(dark energy) and Ω(matter), w provides a three-parameter description of the dark energy. The simplest parametrization of the dark energy is w = constant, although w might depend on → redshift. |
equation of the equinoxes hamugeš-e hamugânhâ Fr.: équation des équinoxes The difference between → apparent sidereal time and → mean sidereal time. It is due to the nutation of the Earth's polar axis of rotation about its precessional motion. It ranges from +0.8 to +1.2 seconds. Also known as → nutation in right ascension. |
equation of time hamugeš-e zamân Fr.: équation du temps The difference, due to Earth's elliptical orbit and variable orbital velocity, between apparent solar time and mean solar time. It varies throughout the year, and slightly from year to year. At present, it reaches extremes of about -14 minutes in February, and about +16 minutes in November. The equation of time is visually illustrated by an → analemma. |
equator hamugâr, estevâ (#) Fr.: équateur The great circle on the surface of a body formed by the intersection of the surface with the plane passing through the center of the body perpendicular to the axis of rotation. → celestial equator. From M.L. æquator "equalizer" (of day and night, as when the sun crosses the equator), from æquare "to make equal, equate" + -tor. Hamugâr, from hamug, → equal + -âr suffix forming agent nous (as in parastâr) or contracted present stem of âvardan "to bring; to cause, to produce." |
equator plane hâmon-e hamugâri Fr.: plan équatorial An imaginary plane → perpendicular to the → axis of a → sphere dividing the sphere into two congruent parts. |
equator system râžmân-e hamugâri Fr.: système équatorial A set of celestial coordinates based on the celestial equator as the primary great circle. The coordinates are → declination and → right ascension. |
equatorial hamugâri Fr.: équatorial Of, pertaining to, or near an equator, especially the equator of the Earth. From → equator + -ial, variant of → -al. Hamugâri, from hamugâr, → equator, + adj. suffix -i. |
equatorial bulge barâmadegi-ye hamugâri Fr.: bourrelet équatorial The excess of the Earth's equatorial diameter over the polar diameter. → equatorial; bulge, from O.Fr. bouge "leather bag," from L. bulga "leather bag," of Gaulish origin. Barâmadegi, from barâmadan "to grow out; to emerge," from bar- "on, upon, up" (Mid.Pers. abar, O.Pers. upariy "above; over, upon, according to," Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + âmadan "to come" (Mid.Pers. âmadan; O.Pers. gam- "to come; to go;" Av. gam- "to come; to go," jamaiti "goes;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come"). |
equatorial coordinate system râžmân-e hamârâhâ-ye hamugâri Fr.: système de coordonnées équatoriales An astronomical → coordinate system for indicating the positions of → celestial objects on the → celestial sphere. The system consists of two components, → right ascension and → declination. Right ascension is the angle between the → vernal equinox and the point where the → hour circle intersects the → celestial equator. The right ascension is always measured eastward from the vernal equinox, in the units of hours, minutes, and seconds. Declination is the angle between the celestial equator and the position of the star measured along the star's hour circle. It is measured in degrees, minutes, and seconds north or south of the celestial equator. By definition, the vernal equinox is located at right ascension 0h and declination 0°. Equatorial coordinates change with time due to the → precession of the Earth's → rotation axis. → equatorial; → coordinate; → system. |
equatorial coordinates hamârâhâ-ye hamugâri Fr.: coordonnées équatoriales Celestial coordinates in the → equator system. → equatorial, → coordinate. |
equatorial mounting barnešând-e hamugâri Fr.: monture équatoriale A telescope mounting consisting of a polar axis pointed toward the celestial pole, and a declination axis supporting the instrument at right angles to the polar axis. → equatorial; → mounting. |
equatorial plane hâmon-e hamugâri Fr.: plan équatorial The plane containing a celestial object's equator. → equatorial; → plane. |
equatorial radius šo'â'-e hamugâri Fr.: rayon équatorial Of a planet, the distance from the center to the equator. For Earth it is 6,378.1370 km. Jupiter has an equatorial radius 11.2 times Earth's value. → equatorial; → radius. |
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