On line quality control in industrial plants is an open field for signal processing applications. In this paper we present a realtime prototype for the detection of microcracks in tiles of wet ceramic by means of ultrasonics. We also describe the signal processing algorithm applied and particularly how the false alarm probability (PFA) may be controlled. Finally an experimental test shows the a...

The capability of embedded piezoelectric wafer active sensors (PWAS) to perform in-situ nondestructive evaluation (NDE) is explored. Laboratory tests are used to prove that PWAS can satisfactorily perform Lamb wave transmission and reception. Subsequently, crack detection in an aircraft panel with the pulseecho method is illustrated. For large area scanning, a PWAS phased array is used to creat...

We report an innovative high pressure method combining the diamond anvil cell device with the technique of picosecond ultrasonics. Such an approach allows us to measure sound velocity and attenuation of solids and liquids under pressure of tens of GPa, overcoming all the drawbacks of traditional techniques. The power of this experimental technique is demonstrated in studies of lattice dynamics ...

Periradicular surgery is often used as a last resort to save an endodontically treated tooth with a persistent periapical lesion. The introduction of surgical microscopes, ultrasonics, and compatible root-end filling materials has made periradicular surgery a much more predictable treatment. The advantages of modern periradicular surgery include easier identification of root apices, smaller ost...

In this short communication, it is demonstrated that the main results obtained by the authors of the commented paper, ''Effect of the surface free energy on the behaviour of surface and guided waves", by V. Vlasie Belloncle, M. Rousseau Ultrasonics, 45 (2006) 188-195, have been well-established long before publication of this paper. Therefore, the claim to novelty asserted by the authors is inc...

INTRODUCTION During the last three years my interest in the use of ultrasonics for the detection of corrosion and the measurement of remaining wall thickness has been re-awakened. The method has been extensively used to verify and quantify Magnetic Flux Leakage (MFL) results. Discrepancies between ultrasonic and MFL results have usually been put down to "Another MFL false call." However, having...

Clinicians are frequently challenged by endodontically treated teeth that have obstructions, such as hard impenetrable pastes, separated instruments, silver points or posts in their root canals. Intracanal separation of endodontic instruments may hinder cleaning and shaping procedures within the root canal system, with a potential impact on the outcome of treatment. Broken instruments usually p...

The time and Fourier domain Synthetic Aperture Focusing Technique (SAFT and FSAFT) have been used to improve both sensitivity and lateral resolution of ultrasonic NDT. Following acquisition of signals over the surface of the tested piece, SAFT identifies a defect by summing all the signals within a certain area (the aperture) after giving proper time-delays. FSAFT, although using the same data,...