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We present an acoustic interference microscope. This device employs a continuous Tx signal and the time-of-flight of the echoes are calculated from interference between incident and reflected waves by an inverse Fourier transform. Using a 175 MHz focused transducer we measured a B-scan across a 5 µm silicon step sample with both the acoustic interference and a conventional ultrasound microscope. The...
The feasibility of using the nonlinear effect of primary circumferential guided wave (CGW) propagation for evaluating accumulated damage in circular tubes is investigated. For a given circular tube, an appropriate mode pair of fundamental and double frequency CGWs is chosen to enable that the second harmonic of the primary wave mode can accumulate along the circumferential direction. After the given...
Structural health monitoring, such as bridge and building is important. The wireless and passive sensor is the best for the monitoring. An impedance-loaded surface acoustic wave (SAW) sensor is a combination of a SAW device and a classical sensor. If the impedance-loaded SAW sensor can apply to the structural health monitoring, wireless sensing system is realized. For the monitoring, damage of the...
In this work we implement an experimental setup to quantify the angular momentum transferred by an acoustic vortex (AV) to disk-like samples of flat and helical surface. To produce an AV of m=1, we have fabricated a multitransducer of 123 ultrasonic elements (40 kHz) deployed on a triangular lattice and spatially shifted to create a radiant helicoid. The samples to be rotated by the AV were supported...
Acoustic properties for Ca3Nb(Ga1−xAlx)3Si2O14 [CNGAS(x)] single crystals were experimentally investigated as a function of Al substitution content. Several plate specimens of the X-, Y-, Z-, 40°Y-, and 145°Y-cut were prepared from CNGAS(x) single crystal ingots (x=0, 0.25, and 0.50) grown by Czochralski technique. Velocities of longitudinal wave, shear wave, and leaky surface acoustic wave (LSAW)...
The harmonic imaging mode is today a fundamental part of ultrasound imaging; it is not only used for suppressing the grating lobe artifact, but also to reduce many other acoustical artifacts in the ultrasound image. A vital performance parameter for accepting CMUT probes as a clinical usable transducer technology is, that it can support harmonic imaging. The large bandwidth of the CMUT is a clear...
In the context of subterrain well inspection, it is important to efficiently and accurately evaluate the quality of the cement sheath that fills the annular region between the rock formation and the casing, which is a string of steel tubes. A continuously increasing number of such wells are being drilled in extreme environments requiring heavy, attenuative fluid filling the borehole for well stabilization,...
The potential of additive manufacturing (AM) to revolutionize aspects of industrial production is widely recognized. AM can create objects with non-uniform properties by varying the ratio between deposited materials or altering the internal structure of the object. Amongst many possibilities, such AM objects could benefit the design and fabrication of different passive components of ultrasonic transducers,...
A new concept for designing an integrated chemical multisensor with only two ports based on surface acoustic waves is presented. Following a principle from antenna theory an acoustic group antenna is assembled consisting of a number of identical interdigital transducers that are fed with currents of equal amplitude, but with a phase difference between neighbors. The propagation of the wave launched...
Compressed-sensing (CS) based beamformers have drawn increasing interest in ultrasound community for their potential of providing better image quality with fewer data. In practice, this framework usually requires good signal models for data explanation and the final estimation could be sensitive to model imperfectness on real data. In this paper, we extend our previous work [1] and robustify the compressed...
We consider the problem of measuring short surface acoustic wave pulses directly in the time domain. The time-shearing differential optical interferometer setup described in this work is extremely sensitive and requires noise calibration. In order to test the accuracy of the response of the interferometer, different parameters of the experimental setup are varied. An input chirp is used to excite...
In this study the acoustic properties of thin slices of the IEC agar-based TMM were assessed over the frequency range of 4.5MHz to 50MHz for a period of 1 year at 3 monthly intervals. To maximize the acoustical stability of the TMM it was both assessed and stored in the same fluids as used in its manufacture (water, glycerol and benzalkonium chloride). A high frequency ultrasound scanner Vevo 770®...
The objective of this initial study is to investigate acoustic microscopy as a tool to elucidate the relationship between microscopic structural properties of the sclera and its macroscopic mechanical properties in healthy and myopic conditions. Excised sclera from both eyes of one guinea pig were scanned with a custom-built scanning acoustic microscope (SAM). Prior to euthanasia and excision, the...
In this paper, ultra-high speed shadowgraphic imaging at 10 × 106 frames-per-second with an effective temporal resolution of 10ns per frame, is used to characterise aspects of the acoustic field, the medium of propagation, and phase characterization of a needle hydrophone. Specifically, at the third harmonic of the driving transducer, constructive and destructive interference is observed in close...
In this work, we have developed a small, handheld histotripsy transducer where the ablation focus is imaged in real-time using a co-registered 45 MHz 64-element phased array endoscope. The construction of a 2 cm diameter, 40% volume fraction, strongly curved, PZT5A composite transducer capable of generating cavitation within tissue is outlined. The co-registered imaging and ablation tool was able...
The determination of precise material parameters is indispensable for an accurate modeling of the electrical response of a BAW resonator and further filter modules. The prediction accuracy is highly dependent on the material parameters used in simulation, where small discrepancies between simulation parameters and actual parameters as achieved during production can result in prediction errors in the...
Novel tough hydrophones were developed by the depositing hydrothermally synthesized lead zirconate titanate thick film on the back-side surface of titanium plate to protect from acoustic cavitation. This hydrophone was resistant to damage at a high-intensity acoustic field generated by a high-intensity focused ultrasound (HIFU) transducer. Since the generation of acoustic bubbles cannot be avoided...
Real time in situ characterisation of solids concentration would aid operational understanding and improve efficiency in many industrial systems. This is especially true in the processing of legacy nuclear wastes where hazardous material is encountered. Acoustic methods have been previously demonstrated for the measurement of concentration in solid-liquid systems at a small scale. This study explores...
Guided waves in plates and cylinders exhibit the backward propagation that group and phase velocities have opposite directions. Backward waves might be used to control the acoustic energy flux. The existence of backward waves in acoustic waveguides has been well established, but the direct visualization of the propagation of backward modes has not been widely reported. The dynamic photoelastic method...
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