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In this study a theoretical approach for the estimation of ultrasonic attenuation is proposed. The approach combines two models which take into account both absorption and scattering. Attenuation due to absorption is studied by using the Biot’s analytical model whereas that due to scattering is described by means of a generalized weak scattering model which is formulated for binary mixtures. The scattering...
Mainly produced in the Mediterranean countries, olive oil excels by its nutritional and medicinal benefits. However, olive oil available in the market is not always authentic. It can be altered by inadequate storage conditions or if it is mixed to other kinds of oils. The objective of this work is to use ultrasonic methods for a possible quick detection of olive oil adulteration from the characterization...
Nonlinear Wave Modulation Spectroscopy (NWMS) is one of the most powerful techniques used to detect damage in materials. It consists in simultaneously applying two continuous waves with different frequencies, the one high, ƒ2, and the other low, ƒ1. When the material is damaged, the frequency spectrum exhibits harmonics and sidebands which are located at (ƒ2 + ƒ1) and (ƒ2 − ƒ1). This paper presents...
Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (100), Pt (111)/Ti/SiO2/Si and Al (111)/SiO2/Si) at different substrate temperatures (from 100 to 500°C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly...
The ZnO thin films in Al/ZnO/Pt/Ti/SiO2/Si Bulk Acoustic Wave (BAW) resonators are realized by a reactive Pulsed Laser Deposition (PLD) technique. It is of most interest to improve their piezoelectric characteristics. These later are intimately linked to the microstructure, the texture and the growth conditions. In this work, the piezoelectric characteristics of ZnO thin films have been investigated...
The FBAR (Film Bulk Acoustic Resonator) is an ultrasonic transducer consisting of a piezoelectric film which is taken as sandwich between two planar metallic electrodes. The lateral dimensions of this MEMS (Micro Electro Machinated System) are considered very large compared to its thickness [1–3].
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