An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : adiabatic
adiabatic
  بی‌دررو   
bidarrow (#)

Fr.: adiabatique   

A → thermodynamic process that occurs without → loss or → gain of → heat.
See also: → adiabatic change, → adiabatic index, → adiabatic initial conditions, → adiabatic phase, → adiabatic process, → adiabatic shock, → adiabatic temperature gradient, → superadiabatic temperature gradient.

From Gk. adiabatos "impassable," from a- "not" + diabatos "passable," from diabainein "to go across," from dia- " through" + bainein "to go."

Bidarrow from bi- "not; without" + darrow "way out," from dar "out" + row "to go, going," from raftan "to go."

adiabatic change
  دگرشد ِ بی‌دررو، دگرش ِ ~   
degaršod-e bidarrow, degareš-e ~

Fr.: changement adiabatique   

A change taking place in a system that has perfect thermal insulation, so that heat cannot enter or leave the system and energy can only be transferred by work.

adiabatic; → change.

adiabatic index
  دیشن ِ بی‌دررو   
dišan-e bidarrow

Fr.: indice adiabatique   

Of a gas, the ratio of its → specific heat at constant pressure to its specific heat at constant volume: γ = CP/ CV.

adiabatic; → index.

adiabatic initial conditions
  بوتارهای ِ آغازین ِ بی‌دررو   
butârhâ-ye âqâzin-e bidarrow

Fr.: conditions initiales adiabatiques   

The assumption whereby the density fluctuations in the very → early Universe would be produced by compressing or decompressing of all components of a homogeneous Universe. The adiabatic initial conditions lead to coherent oscillations in the form of peaks in the → temperature anisotropy spectrum. See also → acoustic peak, → baryon acoustic oscillation.

adiabatic; → initial; → condition.

adiabatic phase
  فاز ِ بی‌دررو   
fâz-e bidarrow

Fr.: phase adiabatique   

Same as the → Sedov-Taylor phase.

adiabatic; → phase.

adiabatic process
  فراروند ِ بی‌دررو   
farâravand-e bidarrow

Fr.: processus adiabatique   

A → thermodynamic process in which no → heat is supplied to or rejected from a system. → polytropic process.

adiabatic, → process.

adiabatic shock
  تش ِ بی‌دررو   
toš-e bidarrow

Fr.: choc adiabatique   

A → shock wave without → radiative cooling. The term "adiabatic" refers to the fact that no → heat is removed during shock.

adiabatic; → shock.

adiabatic temperature gradient
  زینه‌ی ِ دمای ِ بی‌دررو   
zine-ye damâ-ye bidarrow

Fr.: gradient de température adiabatique   

The temperature gradient defining the → radiative equilibrium condition in a region. It is expressed as: dT/dr = (1 - 1/ γ)((T / P)(dP / dr), where T and P are temperature and pressure, dT / dr and dP / dr temperature and pressure gradients respectively, and γ = CP / CV. For radiative equilibrium to be stable against → convection, the actual temperature gradient must be less than the adiabatic temperature gradient, i.e. |dT /dr|rad < |dT /dr|ad. See also → Schwarzschild's criterion.

adiabatic; → temperature; → gradient.

superadiabatic temperature gradient
  زینه‌ی ِ دمای ِ اَبَر-بی‌دررو   
zine-ye damâ-ye abar-bidarrow

Fr.: gradient de température super-adiabatique   

A condition in which there is an excess of the actual temperature gradient over the → adiabatic temperature gradient corresponding to the same pressure gradient. A region with superadiabatic temperature gradient is convectively unstable. → Hayashi forbidden zone.

super-; → adiabatic; → temperature; → gradient.