An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 6 Search : shear
cosmic shear
  کرن ِ کیهانی   
karn-e keyhâni

Fr.: cisaillement cosmique, ~ gravitationnel   

The distortion of images of distant galaxies due to → weak gravitational lensing by → large-scale structures in the → Universe (see, e.g., Kilbinger, M., 2015, arXiv:1411.0115).

cosmic; → shear.

Keplerian shear
  کرن ِ کپلری   
karn-e Kepleri

Fr.: cisaillement keplerien   

Shearing motion of an ensemble of particles, each on a nearly circular, → Keplerian orbit. → Orbital velocity decreases as orbital radius increases, yielding shear. Viscous drag on such shear, due to ring-particle collisions, plays a key role in ring processes (Ellis et al., 2007, Planetary Ring Systems, Springer).

Keplerian; → shear.

shear
  ۱) کرن؛ ۲) کرنیدن   
1) karn; 2) karnidan

Fr.: 1) cisaillement; 2) cisailler   

1) (n.) General: A scissors of large size.
Physics: A → stress applied to a body in the plane of its faces or perpendicular to its axis. As a consequence, parallel planes in the body remain parallel, but are displaced in a direction parallel to themselves. See also → strain.
2) (v.) General: To cut hair, fleece, or foliage from the surface of something using a sharp tool.
Physics: To cause something to deform or break by applying forces acting parallel to the plane.

M.E. sheren, O.E. sceran, scieran; cf. O.H.G. scrinden "to split;", Du. scheren, Ger. scheren "to shear;" from PIE *(s)ker- "to cut, to scrape, to hack;" cf. Pers. kârd "knife;" Av. kart- "to cut;" Skt. krntáti "cuts;" Gk. keirein "to cut, shear;" Lith. skiriu "to separate."

1) Karn, from Laki caré, Farâhâni carra, Tabari carci "a scissors for cutting sheep wool," cognate with Pers. kârd "knife; " Mid.Pers. kârt "knife," karēnītan, karītan "to cut;" Av. karət- "to cut;" cf. Skt. kart- "to cut," krpāna- "sword, knife;" Gk. karpos "fruit;" L. carpere "to cut, divide, pluck;" PIE base *(s)ker- "to cut."
Karnidan infinitive from karn.

shear modulus
  پیمون ِ کرن   
peymun-e karn

Fr.: module de cisaillement   

The ratio of the applied → stress to the change in shape (→ strain) produced in an → elastic body. The bigger this quantity the more rigid is the material since for the same change in strain a bigger force is needed. Also called → shear modulus.

shear; → modulus.

shear turbulence
  آشوبناکی ِ کرنی   
âšubnâki-ye karni

Fr.: turbulence de cisaillement   

A type of → instability occurring within a → fluid as a result of the → shear caused by → differential rotation. The condition for shear instability is expressed by the → Richardson criterion. Shear turbulence is likely the most efficient → mixing process in stellar → radiative zones.

shear; → turbulence.

shear wave
  موج ِ کرنی   
mowj-e karni

Fr.: onde de cisaillement   

A wave that occurs in an elastic medium with the disturbances perpendicular to the direction of motion of the wave. Shear waves do not propagate through a fluid. Also called S-wave, secondary wave, and transverse wave.

shear; → wave.