Therefore it follows that the applicability of formula (2) is limited by the
critical frequency value, [f.sub.cr].
For such adaptivity, the
critical frequency [[omega].sub.ci] is online tuned to be the dominant modal frequency of the cable-damper system identified from the measured cable response [v.sub.d] with the employment of the HHT technique [28].
The
critical frequency [f.sub.cr]) occurs when the structural and acoustic wavelengths are equal to one another and is expressed as
Depending on the material and the stress level, the specimen surface temperature rise can be stabilized at a maximum frequency referred to as
critical frequency. At frequencies above the
critical frequency, temperature rise can continuously increase and the temperature in the material can even reach the melt point.
The peak value of electron density of [F.sub.2] layer is calculated with respect to measured ordinary
critical frequency as given in the expression, equation (3) postulated by Anderson and Matsushita in 1974 (Robert and Andrew, 2004; Barclay, 2003).
Suppose that the
critical frequency at the Earth's equator [f.sub.c0], calculated as [f.sup.2.sub.c0] = K x [N.sub.max] [being K = ([q.sup.2.sub.e]/[[epsilon].sub.0])/(4[[pi].sup.2][m.sub.e]) = 8.061382, [10.sup.-5] [MHz.sup.2] x [cm.sup.3]], can assume the following values: [f.sub.c0] = 3.65 MHz, [f.sub.c0] = 5.65 MHz, [f.sub.c0] = 6.85 MHz, [f.sub.c0] = 7.60 MHz, [f.sub.c0] = 7.80 MHz, [f.sub.c0] = 8.60 MHz, [f.sub.c0] = 9.15 MHz, and [f.sub.c0] = 10.45 MHz.
In another study, Zagatto and colleagues (27) with the objective of testing the validity of the
critical frequency model determined by using a specific protocol on table tennis, the researchers analyzed the aerobic (critf) and anaerobic (anaerobic work capacity--AWC) parameters of the model, the realization of two specific tests on table tennis and two on conventional ergometers were proposed.
(2008b) validated a
critical frequency specific test (critf) for estimating the aerobic endurance of table tennis players.
Perrone, "A local ionospheric model for forecasting the
critical frequency of the F2 layer during disturbed geomagnetic and ionospheric conditions," Annals of Geophysics, Vol.