Publications

The quest for more sophisticated methods imparts a significant challenge in the field of nondestructive testing (NDT) and material characterization. In this paper, we present and discuss experimental polar scans of typical carbon fibre reinforced composite materials recorded with shock wave transducers at frequencies ranging from 1 to 5 MHz. Besides the well-known measurements performed in transmission (T) and double through transmission (2T), ...

In a conventional ultrasonic polar scan (UPS) experiment, the amplitude or time-of-flight-diffraction (TOFD) values of the transmitted and/or reflected acoustic pulse are recorded for a wide range of incidence angles, in view of gaining knowledge about the elastic properties at the insonified material spot. Here we apply the pulsed UPS technique and investigate the backscattered signal, resulting in the ultrasonic backscatter polar scan (UBPS). ...

The conventional ultrasonic polar scan (UPS) records the transmitted amplitude of an acoustic pulse for a certain solid angle, resulting into a unique fingerprint of the local critical bulk wave angles, which relate to the local elasticity tensor at the insonified material spot. Numerical plane wave computations reveal that the use of harmonic sound, instead of sound pulses, provides a picture that exposes the leaky Lamb wave angles. For the ...

In a conventional ultrasonic polar scan (UPS) experiment, the amplitude or time-of-flight-diffraction (TOFD) values of the transmitted and/or reflected acoustic pulse are recorded for a wide range of incidence angles, in view of gaining knowledge about the elastic properties at the insonified material spot. Here we apply the pulsed UPS technique and investigate the backscattered signal, resulting in the ultrasonic backscatter polar scan (UBPS). ...

In a conventional ultrasonic polar scan (UPS) experiment, the amplitude or time-of-flight-diffraction (TOFD) values of the transmitted and/or reflected acoustic pulse are recorded for a wide range of incidence angles, in view of gaining knowledge about the elastic properties at the insonified material spot. Here we apply the pulsed UPS technique and investigate the backscattered signal, resulting in the ultrasonic backscatter polar scan (UBPS). ...

The conventional ultrasonic polar scan (UPS) records the transmitted amplitude of an acoustic pulse for a certain solid angle, resulting into a unique fingerprint of the local critical bulk wave angles, which relate to the local elasticity tensor at the insonified material spot. Numerical plane wave computations reveal that the use of harmonic sound, instead of sound pulses, provides a picture that exposes the leaky Lamb wave angles. For the ...

The conventional ultrasonic polar scan (UPS) records the transmitted amplitude of an acoustic pulse for a certain solid angle, resulting into a unique fingerprint of the local critical bulk wave angles, which relate to the local elasticity tensor at the insonified material spot. Numerical plane wave computations reveal that the use of harmonic sound, instead of sound pulses, provides a picture that exposes the leaky Lamb wave angles. For the ...

The Ultrasonic Polar Scan (UPS) is a non-destructive technique which insonifies a material spot on a sample using ultrasonic pulses from as many oblique incidence angles U+03C8(U+03C6,U+03B8) as possible. Mapping the transmitted time-of-flight (TOF) and/or amplitudes as function of the incidence angle U+03C8(U+03C6,U+03B8) in a polar representation yields a UPS image with intriguing patterns that represent a fingerprint of the local ...

Interface recombination is one of the factors limiting the performance of Cu(In,Ga)Se_2 (CIGS). Especially in the absence of band grading at the front and rear surface, interface passivation approaches become important to improve device performance. The integration of an oxide layer as passivation layer at the front surface of the CIGS requires meticulous considerations in order not to impact the further steps of the solar cell production. In ...

Objectives. (1) To evaluate the effect of cavity depth and composite type on the interfacial debonding in bulk-filled cavities. (2) To correlate the theoretical shrinkage stress and the level of interfacial debonding determined by acoustic emission (AE).Methods. 80 sound molars were divided in two groups to receive a Class-I cavity (3.5 × 3.5mm) with 2.5- or 4.0-mm depth. The cavities were restored with either a conventional pastelike (Filtek ...