Читать книгу Monument Future - Siegfried Siegesmund - Страница 361

The measurements on the ultrasound phantoms prove the principle functionality of the new ultrasound system in the creation of tomography on stone. The positioning of the ultrasonic transducers with the holding system takes approx. 30 min. and the recording of the positions approx. 10 min. The actual measurements and the calculation of the tomography take approx. 20 min. with max. 32 transducers. The determination of a tomography is thus easily possible within one hour. The transmission voltage of 1,000 Vpp at 9 mm aperture of the transducers is not sufficient to receive evaluable signals in case of strongly weathered and fissured marble. In addition in all cases, the high transmit voltage on the multiplexer generates a coupling to the receive channels. The resulting signals allows a reliable measurement only from 150 mm marble thickness.