Fr.: environnement biotique
Ecology: The environment consisting of living organisms, which interact with each other and with their non-living surroundings.
Biotic adj. of → biotics; of → environment.
An object, discovered in 1977, which was initially assumed to be an asteroid, but subsequent observations showed it to be a weak comet with a detectable coma. Its orbit, lying now between those of Saturn and Uranus, is unstable on time scales of a million years.
In Gk. mythology, Xειρων (Cheiron or Chiron) was the wisest of the Centaurs; he was not a drunkard like other Centaurs. Chiron was tutor to Jason and Heracles. He was the only immortal centaur.
Fr.: environnement circumstellaire
The circumstances or physical conditions related to the immediate surroundings of a star.
→ circumstellar; → environment.
1, 2, 3) pargir (#); 3) zistbum
1) An aggregate of surrounding → circumstances,
→ conditions, or → influences
in which a thing is situated or is developed.
From environ + -ment; the first component from Fr. environs, plural of O.Fr. environ "compass, circuit," from environ (adv.) "around," from en- "in" + viron "circle, circuit," from virer "to turn."
Pargir, from par- "around, surrounding," variant pirâ-→ circum- + gir agent noun and
present stem of gereftan "to take, seize; to make prisoner; to intercept"
(Mid.Pers. griftan; Av./O.Pers. grab- "to take, seize;" cf.
Skt. grah-, grabh- "to seize, take," graha
"seizing, holding, perceiving;" M.L.G. grabben "to grab,"
from P.Gmc. *grab; E. grab "to take or grasp suddenly;"
PIE base *ghrebh- "to seize").
Fr.: fer ferrique, fer trivalent
Iron in a plus-3 → oxidation state. Ferric iron needs to share three electrons with an oxygen molecule to make the ion neutral.
Fr.: fer ferreux, fer bivalent
Iron in a plus-2 → oxidation state.
A metallic → chemical element occurring abundantly in
combined forms and used alloyed in a wide range of important tools and structural materials;
→ Atomic number 26;
→ atomic weight 55.845;
→ melting point about 1,535°C;
→ boiling point about 2,750°C;
→ specific gravity 7.87 at 20°C;
→ valence +2, +3, +4, or +6.
Iron is of critical importance to life, i.e. plants, humans, and animals. It occurs in
hemoglobin, a molecule that carries → oxygen
from the lungs to the tissues and then transports
→ carbon dioxide (CO2) back from the tissues
to the lungs.
Iron, from O.E. isærn, from P.Gmc. *isarnan
(cf. O.S. isarn, O.N. isarn, M.Du. iser, O.H.G. isarn,
Ger. Eisen) "holy metal" or "strong metal," probably
an early borrowing of Celt. *isarnon (cf. O.Ir. iarn, Welsh haiarn),
from PIE *is-(e)ro- "powerful, holy," from PIE *eis "strong"
(cf. Skt. isirah "vigorous, strong," Gk. ieros "strong").
Âhan, Kurd. âsan, Mid.Pers. âhan; Av. aiianhaēna- "made of metal," from aiiah- "metal;" cf. Skt. áyas- "iron, metal;" L. aes "brass;" Goth. aiz "bronze;" O.H.G. ēr "ore" (Ger. Erz "oar"); O.E. ora "ore, unworked metal," ar "brass, copper, bronze."
asr-e âhan (#)
Fr.: âge du fer
The period generally occurring after the → Bronze Age, marked by the widespread use of iron. Its date and context vary depending on the country or geographical region. The Indo-European Hittites are the first people to work iron, in the Asia Minor, from about 1500 BC.
iron convection zone (FeCZ)
zonâr-e hambaz-e âhan
Fr.: zone convective du fer
A → convective zone close to the surface of → hot stars caused by a peak in the → opacity due to iron recombination. A physical connection may exist between → microturbulence in hot star atmospheres and a subsurface FeCZ. The strength of the FeCZ is predicted to increase with → metallicity and → luminosity, but decrease with → effective temperature. The FeCZ in hot stars might also produce localized surface magnetic fields. The consequence of the FeCZ might be strongest in → Wolf-Rayet stars. These stars are so hot that the → iron opacity peak, and therefore FeCZ, can be directly at the stellar surface or, better said, at the → sonic point of the wind flow. This may relate to the very strong → clumping found observationally in Wolf-Rayet winds, and may be required for an understanding of the very high → mass loss rates of Wolf-Rayet stars (See Cantiello et al. 2009, A&A 499, 279).
→ iron; → convection; → zone.
Fr.: cœur de fer
1) Electromagnetism: A bar of → soft iron that passes
through a coil and serves to increase the → inductance of
šaxâne-ye âhani (#)
Fr.: météorite ferreux
A meteorite which is composed mainly of iron mixed with smaller amounts of → nickel. Iron meteorites make up about 4.4% of all meteorites. See also → stony meteorite, → stony-iron meteorite.
iron opacity peak
setiq-e kederi-ye âhan
Fr.: pic d'opacité du fer
A bump appearing in the plot of stellar → opacity versus temperature. The ionization of the heaviest → chemical elements, especially → iron, which is the most abundant heavy metal, produces a large number of weak spectral → absorption lines. These lines dominate the stellar opacity in the temperature range 105-106 K and furnish two local opacity peaks: a large peak around 2 × 105 K and a smaller one around 1.5 × 106 K (Rogers & Iglesias, 1992, ApJS 79, 507; Iglesias et al. 1992, ApJ, 397, 717).
Fr.: pic du fer
A maximum on the element-abundance curve in the vicinity of the iron → atomic number 26. The relative higher abundance of the → iron peak elements results from their being the end products of → nucleosynthesis in the interiors of → massive stars.
iron peak element
bonpâr-e setiq-e âhan
Fr.: élémént du pic du fer
A member of a group of elements with → atomic masses A about 40 to 60 that are synthesized by the → silicon burning process and appear in the → iron peak. They are mainly: → titanium (Ti), → chromium (Cr), → manganese (Mn), → iron (Fe), → cobalt (Co), and → nickel (Ni).
1) Using words to convey a meaning that is the opposite of its
literal meaning; containing or exemplifying irony: an ironic novel; an
Fr.: 1) ironie; 2) ironiser
1) The humorous or mildly sarcastic use of words to imply the opposite
of what they normally mean. → ironic.
From L. ironia, from Gk. eironeia "dissimulation, assumed ignorance," from eiron "dissembler," perhaps related to eirein "to speak."
Govâžé, ultimately from Proto-Ir. *ui-vac-, from *ui- prefix denoting "apart, away, out," cf. Av. vi-, O.Pers. viy-, Skt. vi- (Mod.Pers., e.g., gozidan, → select, gozaštan "to cross," → passage) + *uac- "to say, speak," → word; also govâžidan "to make irony of, to say ironically."
Fr.: environnement faible en métaux
A medium in which chemical elements have abundances smaller than the solar values.
→ low; → metallicity; → environment.
Fr.: environnement riche en métaux
An environment (→ galaxy, → nebula) whose → metallicity is larger than that of the → Milky Way galaxy.
→ metal; → rich; → environment.
Fr.: ironie socratique
A means by which the pretended ignorance of a skillful questioner leads the person answering to expose his own ignorance (Collins).
Fr.: fer doux
Iron that has a low carbon content, in contrast to → steel. Because it is easily magnetized and demagnetized, it is used to make the cores of → solenoids and other electrical equipment.