A suffix denoting "turned toward" that specified by the initial element; → barotropic, → isotropic, → polytropic.
From Gk. -tropos "a turn, way, manner," from tropein "to turn," from PIE base *trep- "to turn" (cf. L. trepit "he turns").
Gard "turning, changing," from gardidan "to turn, to change," Mid.Pers. vartitan, Av. varət- "to turn, revolve," Skt. vartati, L. vertere, O.H.G. werden "to become;" PIE *werto, *wer-.
Describing a medium in which certain physical properties are different in different directions.
→ anisotropy; → -ic.
anisotropic homogeneous cosmological model
model-e keyhânšenâxti-ye hamgen o nâ-izogard
Fr.: modèle cosmiologique homogène mais anisotrope
A solution to Einstein's theory of → general relativity that is spatially homogeneous but allows for rotation and/or shear. See also → Bianchi cosmological model.
→ anisotropic; → homogeneous; → cosmological; → model.
In a fluid, conditions where surfaces of constant pressure are parallel to surfaces of constant temperature. This state is equivalent to zero → baroclinicity.
Fr.: gaz barotrope
A gas whose density is a function solely of pressure.
→ barotropic; → gas.
Fr.: instabilité barotrope
A hydrodynamical instability that arises when the horizontal → shear gradient becomes very large. Barotropic instabilities grow by extracting kinetic energy from the mean flow field.
→ barotropic; → instability.
Cancer, Tropic of
Fr.: Tropique du Cancer
Capricorn, Tropic of
Fr.: Tropique du Capricorne
Physical chemistry: Describing a substance that is capable of undergoing a change in phase (as from a liquid to a gas), with no change in chemical composition. If the substance is hylotropic over a limited range of pressure and temperatures, it is a pure chemical substance. If it is hylotropic over all pressure and temperatures except the most extreme ones, it is a → chemical element. See also → hylotrope.
First suggested by Wilhelm Ostwald (1904, in Annalen der Naturphilosophie 3, 355), from Gk. hylo-, combining form of hyle "matter; wood," because of the dependence on the composition, + → -tropic.
Having a constant entropy.
Fr.: écoulement isentrope
A → reversible flow in which the value of → entropy remains → constant; i.e. no energy is added to the flow, and no energy losses occur due to friction or dissipative effects.
→ isentropic; → flow.
Fr.: process isentrope
A → thermodynamic process for which there is no → heat transfer with the surroundings, and no change in → entropy.
→ isentropic; → process.
izogard, hamsângard (#)
Having physical properties that do not vary with direction.
giti-ye izogard, ~ hamsângard (#)
Fr.: Univers isotrope
A Universe having observed properties that appear identical in every direction.
1) Math.: Describing a function which has different values for one variable.
degaršod-e bolgašti, degareš-e ~
Fr.: changement polytropique
A change in the → pressure or → volume of a → gas in a → polytropic process.
→ polytropic; → change.
Fr.: gaz polytropique
A gas capable of undergoing a → polytropic process.
→ polytropic; → gas.
Fr.: index polytropique
A number appearing in the equation describing a → polytropic process.
→ polytropic; → index.
Fr.: processus polytropique
A thermodynamic process that obeys the relation:
PVn = C, where P is pressure, V is volume,
n is any real number, called the → polytropic index, and
C is a constant.
→ polytropic; → process.
Either of the two parallels of latitude on Earth at which the Sun appears overhead at the → summer and → winter solstices each year: → Tropic of Cancer, → Tropic of Capricorn . The tropics lie at latitudes 23°26', north and south, an angle defined by the Earth's → axial inclination.
M.E., from L. tropicus, from Gk. tropikos "of or pertaining to a turn or change; of or pertaining to to the turn of the Sun's apparent motion at solstice," from trope "a turning."
Hurgard, literally "Sun's turning," from hur, → Sun, + gard "turning, changing," from gardidan "to turn, to change;" Mid.Pers. vartitan; Av. varət- "to turn, revolve;" Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend."