Piezoelectric micromachined ultrasonic transducers (pMUTs) are an example of the application of MEMS technology to ultrasound generation and detection, which is expected to offer many advantages over conventional transducers. In this work, we investigate pMUTs through novel design and fabrication methods. A finite element (FE) model, with original tools to measure device performance, was develo...

The aim of this work is to develop methods that enable acoustic speech features to be predicted from mel-frequency cepstral coefficient (MFCC) vectors as may be encountered in distributed speech recognition architectures. The work begins with a detailed analysis of the multiple correlation between acoustic speech features and MFCC vectors. This confirms the existence of correlation, which is fo...

1.1 Shear mode bulk acoustic wave devices and sensors Acoustic microsensor technique, well known as QCM (Quartz crystal microbalance) or TSM (Thickness shear mode) sensor, is an effective method to detect small mass loading on the sensor surface. This sensor can be operated even in liquid by using shear mode resonance. Therefore, shear mode piezoelectric film resonators are attractive for liqui...

Abstract: Several nonwovens were studied to explore the relationship between their structural characteristics, permeability and acoustic absorbing behavior. Fundamental structural parameters including thickness, gram square meter and porosity were considered. Results show that the permeability is not just linear to porosity, but also related to many other complex and difficult-to-measure parame...

In ultrasonic NDE, simulation studies can play an important role in complimenting experimental validation of techniques under development. The utility of such simulations depends, in part, on the degree to which the simulated defect and noise signals are representative of the measured signals. In this paper, we describe an approach for generating simulated acoustic noise with a spatial correlat...

An efficiency of the nonsingular meshless method is analyzed in an acoustic indoor problem. The solution assumed form series radial bases functions. Hardy’s multiquadratic functions, as bases, are taken into account. room field with uniform, impedance walls considered. representative, rectangular cross section chosen. Practical combinations of acoustic boundary conditions, expressed through ab...

Optical fibers containing multiple cores are widely regarded as the leading solution to the optical communications capacity crunch. The most prevalent paradigm for the design and employment of multi-core fibers relies on the suppression of direct coupling of optical power among cores. The cores, however, remain mechanically coupled. Intercore, opto-mechanical cross-talk, among cores that are ot...

In this paper a method for the measurement of the oblique incidence sound absorption coefficient is presented. It is based on a local field assumption, in which the acoustic field is locally approximated by one incidentand one specularly reflected plane wave. The amplitudes of these waves can be determined with an unidirectional sound intensity probe. The local activeand incident acoustic inten...

Acoustical and optical signal transmission underwater is of vital interest for both civilian and military applications. The range and signal to noise during the transmission, as a function of system and water optical properties, in terms of absorption and scattering, determines the effectiveness of deployed electro-optical (EO) technology. The impacts from turbulence have been demonstrated to a...

We investigate the impulsively excited acoustic dynamics of nanoscale Au triangles of different sizes and thicknesses on silicon and glass substrates. We employ high-speed asynchronous optical sampling in order to study the damping of the acoustic vibrations with high sensitivity in the time domain. From the observed damping dynamics we deduce the reflection coefficient of acoustic energy from ...