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Modification of dissolved gas content by nucleation of acoustic droplet vaporization (ADV) has been proposed for several therapeutic applications. Reducing dissolved oxygen could inhibit reactive oxygen species production during reperfusion of ischemic tissue, such as during coronary interventions to rescue myocardium. Localization of the effect may be achieved using intravascular ultrasound (IVUS),...
Recently a multilayered structure with a low-velocity layer sandwiched between two high-velocity materials, one of which also works as a supporting substrate and another one as a coat isolating the wave from the influence of undesired external factors, was suggested for application in packageless sensors [1,2]. The thickness of a middle piezoelectric layer must be sufficient to confine the wave within...
In most industrial processes transfer of data and software from or to sensors is an essential part of the monitoring and control systems. Many of the older, wired communication systems have been or are being replaced with wireless alternatives. A number of challenges are associated with this replacement: Radio receivers are subject to interference from other radio sources. Similarly, radio transmitters...
Electro-mechanical devices for sensing, actuation, and communication are necessary ingredients for the ongoing 4th industrial revolution. Piezoelectricity plays an important role in electromechanical conversion, and is e.g. used in ultrasonic imaging and mobile phone communication. The drive for miniaturization will result in a strong demand for piezoelectric thin films, with improved, optimized properties...
Single ultrasound device, capable of operating over dual or multiple frequencies, would benefit and expand a series of applications, such as acoustic cavitation enhancement, transdermal drug release, nondestructive testing, ultrasound and photoacoustic imaging. One of the approaches for a dual-frequency operation is to integrate both high- and low-frequency transducer elements in a single chip [1-3]...
Piezoelectric lead zirconate titanate (PZT) thick films (t>10μm) with excellent electromechanical property have been considered for flexible electronics applications where precise actuation, control and sensing are desired. The main drawback of piezoelectric thick films is the fragility in device fabrication and application. To protect the PZT thick film devices from fracture, a five-layer sandwiched...
RF Voltage transformers operating in one of the ISM frequency bands have recently been demanded in emerging low-power applications, such as wake-up radios in wireless networks, remotely triggered switches, stand-by units in home electronics, etc. S0 Lamb wave resonant (LWR) transformers have been first proposed. Later, SAW transformers designed as “degenerated” CRF have been proposed. Here we demonstrate...
SH-SAW In-liquid sensors have been explored extensively in recent decades. They propose an ability to work at higher frequencies, than the well-known QCM, with the aim to reduce the size and ease the integration in sensor arrays. So far SH-SAW liquid phase sensors are designed in two-port delay line configurations because of the need to protect the IDT from the conductive and dielectric loads from...
Ultrasound offers measurements of parameters encountered in harsh environments such as steam generators, heat exchangers and nuclear reactor primary and secondary systems. But there is a lack of piezo-materials tolerant of high temperatures and nuclear irradiation. Another issue is that transducers are needed that can be left in place on curved surfaces such as pipes and valves. The transducers should...
Touchscreen sensors are widely used in many devices such as smart phones, tablets, laptops, etc. There are many different types of modalities that enable sensing the touch. The dominant technologies on the market are the capacitive, resistive, acoustic or ultrasound, and optical touch systems. None of these technologies are perfect and each has some advantages and disadvantages. Capacitive touch technologies...
Interpretation of Lamb waves signals raises serious difficulties due to their multi-modal and dispersive nature. Different modes propagating with different velocities can be confused and erroneously interpreted as damage-originating components. The S0 and A0 Lamb wave modes, most commonly used for damage identification, exhibit elliptical polarization. Therefore, their in-plane and out-of plane motion...
Recently, the idea of Surface acoustic wave (SAW) current sensor utilizing magnetostrictive effect provides a new effective way for sensing current, which exhibits some superior features as fast response, simple structure, and strong anti-jamming. The representative sensor structure is composed of a configuration of dual-delay-line oscillators, and a magnetostrictive film (FeCo) coated onto the sensing...
Resonant Nanoelectromechanical Systems (NEMS) have generated an enormous interest over the last 15 years, driven by a combination of fundamental questions and practical needs. The combination of relatively high frequencies, high quality factors and small masses make them ideal for a plethora of sensing applications. As an example, it has been possible to detect from a single atom landing on a carbon...
In this paper, we describe the improvement of Impact-Echo (IE) using developed air-coupled array system. The air-coupled array system utilizes microelectromechanical systems (MEMS) to receive leaky waves in concrete-air media without physical coupling process. The air-coupled array system benefits of Lamb wave analysis. It is known that thickness mode frequency measured by IE test is emerged from...
This work describes the results of experiments conducted a part of an instrumented lead test in-core in a nuclear reactor with the piezoelectric and magnetostrictive materials. The experiments exposed AlN, ZnO, BiT, Remendur, and Galfenol to more neutron radiation than found in the literature. The magnetostrictive sensors produce stable ultrasonic pulse-echoes throughout much of the irradiation. The...
The propagation of the S0 Lamb mode in AlN membrane combined with continuous and structured SiO2 thin films is theoretically studied with respect of the materials geometrical parameters and electrical boundaries conditions. A comparison is made in terms of the phase velocity, electromechanical coupling coefficient and temperature coefficients of frequency (TCF) between the studied structures. The...
This paper presents a digital communication system based on Orthogonal Frequency Division Multiplexing (OFDM) and MHz-range ultrasound, for transmission of data through solid materials and liquids. The system is tested on experiments using a off-the-shelf ultrasound transducers with a center frequency of 3.5 MHz as transmitter and receiver, respectively. The propagation medium in the experiment was...
Modification of dissolved gas content by acoustic droplet vaporization (ADV) has been proposed for several therapeutic applications. Reducing dissolved oxygen (DO) during reperfusion of ischemic tissue during coronary interventions could inhibit reactive oxygen species production and rescue myocardium. The objective of this study was to determine whether intravascular ultrasound (IVUS) can trigger...
Nanoscale ultrasound agents have recently gained interest in cancer imaging and therapy for their ability to exploit the enhanced permeability and retention (EPR) effect in tumors. There have been numerous reports of echogenic nanoscale bubbles, but it remains unclear whether these sub-micron bubbles are responsible for producing the observed acoustic backscatter at clinically relevant frequencies...
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