For non-destructive evaluation (NDE) of concrete, efficient and accurate imaging techniques are needed for a reliable evaluation of safety and serviceability of structures. Imaging of concrete structures is considered a very challenging task since it is a non-homogeneous material. In this paper, the acoustic (stress wave) technique was applied by using Ultrasonics and Synthetic Aperture Focusin...

We report a photoacoustic imager that utilizes a focused laser beam in combination with a 20 MHz ultrasound focusing transducer to obtain micron-resolution tissue images over a long working distance. The imager is based on a ring transducer that combines ultrasonic and laser beams collinearly and confocally in a monolithic element. The combination of focused laser beam and short pulse irradiati...

The synthetic aperture focusing technique (SAFT) is often used for imaging in non-destructive ultrasonic testing. Conventional SAFT is well suited for contact testing of homogeneous objects because of the constant sound speed throughout the media, whereas the refraction present in the practically important case of immersion tests has so far prevented a widespread use of SAFT for such data. Fort...

We report on (to our knowledge) the first remote contactless photoacoustic imaging with short excitation pulses on semitransparent solid polymer samples for material inspection. In this work solid semitransparent samples are excited with pulses from a short pulse laser. The local absorption of the electromagnetic radiation leads to generation of broadband ultrasonic waves. Ultrasonic waves arri...

In the last decade, ultrasonic imaging systems have been an essential tool for diagnosis in medical and industrial applications, especially in the Non Destructive Testing area (NDT). Conventional ultrasonic imaging devices produce high quality images with good resolution and contrast. However, these machines are usually associated to a high cost in hardware resources, as well as in the time req...

A frequency-swept ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. The ultrasound-modulated laser light reflects...

In the study reported here, a novel amphiphilic poly(aminoethyl ethylene phosphate)/poly(L-lactide) (PAEEP-PLLA) copolymer was synthesized by ring-opening polymerization reaction. The perfluoropentane-filled PAEEP-PLLA nanobubbles (NBs) were prepared using the O1/O2/W double-emulsion and solvent-evaporation method, with the copolymer as the shell and liquid perfluoropentane as the core of NBs. ...

Context: This thesis is motivated by the development of elastography technique [6]. This is a medical imaging procedure that measures ultrasonic wave propagation inside a biological tissue and aims at identifying the physical properties of the tissue. These properties are of major importance in many medical applications. For instance, it enables the reproduction of the quantitative palpation of...

In ultrasonic medical imaging, spatial compounding of images is a technique where ultrasonic beam is steered to examine patient tissues in multiple angles. In the conventional ultrasonic diagnostic imaging, the steering of the ultrasonic beam is achieved electronically using the phased array transducer elements. In this paper, a spatial compounding approach is presented where the ultrasonic pro...

Cavitation occurs around dental ultrasonic scalers, which are used clinically for removing dental biofilm and calculus. However it is not known if this contributes to the cleaning process. Characterisation of the cavitation around ultrasonic scalers will assist in assessing its contribution and in developing new clinical devices for removing biofilm with cavitation. The aim is to use high speed...