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Acoustic streaming is a promising way for transporting fluid or particles suspended in a fluid in lab-on-a-chip devices and microfluidics in general. In literature usually water is considered as the working medium. In this contribution we present a framework based on perturbation theory, which implements viscoelastic fluid behavior to the acoustic streaming effect expanding the applicability beyond...
Composites are widely used in aviation, aerospace and other fields because of their high specific strength, high specific stiffness and easy molding. However, in the process of using the concentrated stress, heavy shocks may form different degrees of damage. Especially, the internal delamination will reduce the stability and safety of the structure. Based on the analysis of damage location and damage...
Performance of AlN-based electroacoustic devices directly tie with piezoelectric and metal electrode film quality. In this paper, sputter techniques for the reactive sputtering of AlN and ScAlN thin films, for the deposition of highly textured metal electrodes, and for the deposition of multilayer Bragg acoustic reflectors for SMR devices using dual-target S-gun magnetrons are described and some film...
Burst wave lithotripsy (BWL) is an experimental method to noninvasively fragment urinary calculi using low-frequency focused bursts of ultrasound. To optimize many of the acoustic parameters for this technology, it is necessary to understand the physical interactions between ultrasound bursts and stones. In this study, the interaction of elastic waves with model stones was simulated and experimentally...
Through the introduction of multi-frequency sonication in High Intensity Focused Ultrasound (HIFU), enhancement of efficiency has been noted in several applications including thrombolysis, tissue ablation, sonochemistry, and sonoluminescence. One key experimental observation is that multi-frequency ultrasound can help lower the inertial cavitation threshold, thereby improving the power efficiency...
Nonlinear ultrasonic measurements has been proposed to characterize the creep damage evolution of P92 martensitic ferritic steels at a temperature of 650 °C and stresses of 100 MPa and 115 MPa, respectively. The correlation of increase-decrease-increase between the ultrasonic nonlinearity and the creep strain was achieved for both sets of specimens. Considering the metallographic studies, nonlinear...
In order to generate trackable shear waves in soft tissues, transmitted pulses in shear wave elastography (SWE) are longer than conventional clinical ultrasound pulses. Nevertheless, they typically obey mechanical and thermal regulatory limits. In arterial applications, specific safety concerns may arise, as acoustic radiation (ARF)-induced stresses and strain rates could potentially affect the arterial...
The article substantiates the use of the resistance-acoustic method in problems of non-destructive testing of mechanical stresses or defects in structures of metals and alloys in natural and technical systems. The possibilities of the use of the proposed method for the potential monitored facilities were analyzed, to which the strict requirements for operational security are imposed (bearing reinforced...
P92 martensitic ferritic steels are an attractive material for critical components in power industries due to the excellent creep property. However, these steels are usually susceptible to creep strength degradation during a long service period under the elevated temperature and pressure. Creep damage evaluation is of concern to quantitatively assess the remaining lifespan of the critical components...
A residual thickness measurement method for corroded steel plates using ultrasonic waves is presented. In this method, a shear-horizontal (SH) plate wave is transmitted in a steel plate by an SH array transducer, and the echo received by the reflection occurring owing to the cut-off phenomena of the plate wave is utilized. Furthermore, the configuration of the SH array transducer suitable for the...
Investigation of the relationship between acoustic anisotropy and measures of the stress-strain state of specimens from commercial alloy in the case of moderate and large elasto-plastic deformations was carried out. Comparison of the results of mechanical tests with the results of modeling by the finite element method established that the second invariant of the deviator of the strain tensor has the...
Sensitivity of piezoelectric ultrasonic microsensors was investigated with sol-gel derived piezoelectric lead-zirconate-titanate (PZT) films under various pyrolysis temperatures. The sensors were fabricated on thin diaphragm structures, whose buckling deflection strongly affects the sensitivity and is controlled through stress of the PZT film. The pyrolysis temperature in the sol-gel process was varied...
The human body represents the most important topic for many researchers. In our days, the science complexity demands the involvement of many resources and the coordinated team work of doctors, engineers, and other specialists. In the case of dental medicine, due to the nature of teeth material, their dimension and geometrical position, very important problems, like fractures, cannot be studied with...
In this paper the calculation scheme of the transducer of contact type with a piezoelectric element of a diskform is considered. The transducer emits the elastic waves in a massive metal plate. The transmission coefficient of the electrical to mechanical side of the piezoelectric disc is calculated. It is shown that for the effective operation of the transducer at high frequencies, it is necessary...
The structural response of power module busbars under harmonic loads is considered using finite element method simulation. Simulation parameters and boundary conditions are considered in terms of their effect on the accuracy of simulation results with relation to real life application. Vibrational analysis was found to be highly sensitive to geometry preparation and constraint in terms of both mechanical...
This paper presents the design and analysis of a multilayer cantilever to harvest vibration energy by generating acoustic signal. To do so, a five layer configuration is used to design the cantilever. Lead Zirconate Titanate (PZT-8), Stainless Steel 405 Annealed, Aluminum and Zinc Oxide are used to develop the layers. Water is used as the medium to analyze the sound propagation pattern. Sound Pressure...
We address the problem of synthesizing narrow-focus word-stress in TTS by controlling the different prosodic features, namely, duration, F0 and intensity profiles. Towards this, we perform a prosody modification of a neutral carrier sentence to create narrow-focus stress on specific target words, by controlling the three prosodic features at word-level and syllable-level. The specific control of the...
Emotion representations are psychological constructs for modelling, analysing, and recognising emotion, being one essential element of affect. Due to its complexity, the boundaries between different emotion concepts are often fuzzy, which is also reflected in the diversification of emotion databases, and their inconsistent target labels. When facing data scarcity as an ever present issue for acoustic...
This paper reviews the research approaches used in computer-assisted pronunciation training (CAPT), addresses the existing challenges, and discusses emerging trends and opportunities. To complement existing work, our analysis places more emphasis on pronunciation teaching and learning (as opposed to pronunciation assessment), prosodic error detection (as opposed to phonetic error detection), and research...
Human voice can signal the psychological state of an individual. Be it emotional, physical, intentional or unconscious, voice reveals the internal state of the speaker. Therefore, the main aim of the present study is to identify which voice parameter could be used as a reliable indicator of stress due to deception. For analyzing real life natural stress, the voice of crime suspects was recorded during...
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