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It is commonly known that a merry-go-round can be rotated even by a child going along its edge. The angular momentum of the whole system should be equal to zero so that the movement of the child results in a merry-go-round movement in opposite direction. Here we show experimentally that a macroscopic cylindrical solid can be rotated due to the existence of the momentum of surface acoustic wave propagating...
The nondestructive evaluation of cemented steel pipes in underground wells with ultrasonic imaging methods is a common oilfield industry application. In order to ensure the mechanical integrity of the well and in particular the lack of undesired hydraulic communication between different geological zones, the cement quality of the annular region around the pipe is often evaluated through guided leaky...
This contribution is concerned with a technique to precisely measure the physical dimensions of flaws in solid specimen by pulse-echo mode acoustic microscopy. We have implemented a synthetic aperture focusing technique (SAFT), which is based on a semi-numerical simulation approach (SIRFEM). In acoustic microscopy, one normally applies single-element transducers with center frequencies above 10MHz...
The goal of this study was to understand how the roughness of the boundary of two solids surfaces effects their nonlinear elastic properties and the possible usage of these results for the solid state surface diagnostic. The investigation of two media boundary properties was conducted by surface acoustic waves (SAW), which were excited and received in optically polished glass padding with angled beam...
We experimentally investigated how nanostructuring affects the third-order elastic constants Cijklqr (TOECs) and ultrasonic nonlinear parameter N (NP) of the aluminum alloy AMg6 (Al-Mg-Mn system), and we had prepared a nanocomposite 0.3wt.%C60/AMg6 (n-AMg6) from it. The study of the nonlinear elastic properties was conducted in two ways: TOECs were measured by Thurston-Brugger method and the NPs were...
Influence of mechanical force applied parallel to the wedge of an edge (D16 aluminum alloy) on velocity, absorption of acoustic wedge waves and specifics of second harmonic generation is studied experimentally in the paper.
Transmission of a harmonic SAW across the interface between two elastically anisotropic 90°-wedges is studied using FEM in frequency domain. The wedges are in contact along a pair of their faces. The contact is either perfectly rigid or perfectly sliding. The structures under modelling are constructed of LiNbO3, Si and GaAs. It is assumed that the SAW is always incident from LiNbO3. The transmission...
In this paper, we present two frequency-domain algorithms for 2D imaging in solids, namely Stolt's method and Lu's method, the latter being extended to the 3D imaging with matrix arrays. First, the performances of both frequency-domain methods are evaluated in 2D imaging and compared with the time-domain plane wave imaging (PWI). Then, Lu's method and PWI are applied to 3D to image a distribution...
We report on experimental characterization of acoustic band gaps for complex three-dimensional phononic crystals. Utilizing 3D unit cell geometries arranged in a cubic lattice, we can achieve uniquely wider band gaps with stronger suppression of acoustic waves than possible with two-dimensional realizations. Beyond our previously established simple cubic arrangement of three cylindrical holes derived...
Wavelets are known particularly to be an effective tool for extracting discriminative features in the scattered RF signals of both solid and gaseous emboli. However, the selection of an appropriate mother wavelet for the signal being analyzed is an important criterion. This offers the possibility to perform an optimization procedure to obtain the best wavelet. The purpose of the study is to propose...
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