In a self-regulatory system, monitoring a disturbance before it enters the → system to apply corrections before the disturbance has influenced the system. See also → feedback.
1) piš-su; 2) piš-su kardan
Fr.: en avant, en avance
1a) To or toward what is ahead or in front.
From fore "before, in front of," cognate with Pers. farâ, → pro-,+ → -ward.
Piš-su, from piš "forward; in front of; before;" Mid.Pers. pêš, + su, → direction.
Fr.: diffusion en avant
Scattering in which photons emerge from the → scattering medium travelling predominantly in the same direction as they entered. The → halos around the Sun and Moon in wet weather are caused by forward scattering by water droplets in the Earth's atmosphere. → backscattering.
→ forward; → scattering.
forward seismic modeling
modelsâzi-ye larze-yi-ye piš-su
1) Geology: The process whereby a geologic section (subsurface model
of one-, two-, or three dimensions) is transformed into a synthetic seismogram
(synthetic seismic record).
Fr.: choc en avant
A highly → supersonic → shock wave created in a → supernova remnant as the expanding stellar ejecta runs into the → interstellar medium (ISM). This forward shock wave produces sudden, large changes in pressure and temperature behind the shock wave. The forward shock wave also accelerates electrons and other charged particles to extremely high energies. The forward shock front has a velocity of 104 km s-1 and can heat the shocked gas to temperatures ~ 109 K. While the forward shock continues to expand into the ISM, it creates a → reverse shock that travels back into the freely expanding → supernova ejecta.