o t NDTnet - March 1996, Vol.1 No.03
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| A | Ultrasonic reflection from the delay line to specimen interface |
| a | Attenuation coefficient, nepers per unit length (nepers/m) |
| B, C | First and second ultrasonic reflections from the specimen to air interface |
| C | Acoustic velocity (m/s) |
| Ct | Torsion wave velocity |
| D | Diameter (meters) |
| f | frequency (Hz) |
| Io | Intensity of ultrasound (W/m 2 ) |
| L | Length (meters) |
| | Wavelength, distance per cycle of acoustic waveform (m/cycle) |
| o | Wavelength of extensional wave |
| t | Wavelength of torsional wave |
| N | An integer value (1,2,3,...etc.) |
| P+ | Positive acoustic pressure wave |
| P- | Negative acoustic pressure wave |
| P1 | Acoustic pressure in the first medium |
| P2 | Acoustic pressure in the second medium |
| R | Ultrasonic reflection coefficient, propagation in direction of transducer to specimen at the time of reflection |
| r | Ratio of the acoustic impedance of the second medium to the acoustic impedance of the first medium |
| R ' | Returning ultrasonic reflection coefficient, propagation in direction of specimen to transducer at the time of reflection |
| RE | Intensity reflection coefficient |
| RP | Pressure reflection coefficient |
| T | Ultrasonic transmission coefficient, propagation in direction of transducer to specimen |
| T' | Returning ultrasonic transmission coefficient, propagation in direction of specimen to transducer |
| TE | Intensity transmission coefficient |
| TP | Pressure transmission coefficient |
| u x1 | Acoustic particle velocity in first medium |
| u x2 | Acoustic particle velociy in second medium |
| Z1 | Acoustic impedance of first medium |
| Z2 | Acoustic impedance of second medium |
Rolf Diederichs 15.Febr.1996, info@ndt.net