It has been shown that nonlinear ultrasonics can be more sensitive to local incipient defects, such as a fatigue crack, than conventional linear ultrasonics. Therefore, there is an increasing interest in utilizing nonlinear ultrasonics for structural health monitoring and nondestructive testing applications. While the conditions, which are the necessary conditions that should be satisfied for t...

In frequency domain laser ultrasonics, the pulsed laser source used for ultrasound excitation in conventional laser ultrasonics is replaced by a low power, amplitude modulated laser source. The acoustic signals are detected using an interferometer or contact transducer, coupled to a RF lock-in amplifier or vector network analyzer. The detection bandwidth reduction afforded by this technique all...

The aim of this study was to investigate whether the use of operating microscope in combination with ultrasonics increased the rate of second mesiobuccal (MB2) canal detection in permanent maxillary first molar teeth. A hundred extracted human maxillary first molars were assessed. After location of the main canals, the MB2 canal was sought in all teeth first without microscopy, then with the ai...

By relying on optics for providing the transduction of ultrasound, laser-ultrasonics brings practical solutions to a variety of nondestructive evaluation problems that cannot be solved by using conventional ultrasonic techniques based on piezoelectric transduction (1,2]. Laser-ultrasonics uses two lasers, one with a short pulse for the generation of ultrasound and another one, long pulse or con...

OBJECTIVES To evaluate the success of certain methods that can be used in the removal of separated instruments from different levels in curved and straight canals. METHODS Instrument removal attempts were undertaken on 63 straight and 30 curved canals containing a pre-fractured instrument using the ultrasonics under the visualization of an operating microscope or conventional methods. In stra...

Presentations J. Kim, S. Li, X. Jiang “Development of Transmitters in Dual Frequency Transducers for Interventional Contrast Enhanced Imaging”, abstract accepted to 2014 IEEE Ultrasonics Symposium, presented Sept 3-6, 2014. J. Kim, S. Li, S. Kasoji, P. Dayton, X. Jiang, “Development of Transmitters in Dual-Frequency Transducers for Interventional Contrast Enhanced Imaging and Acoustic Angiograp...