according to the former researcher’s presented relations for flow through rock-fill porous media, the effects of physical characteristics was not studied separately. hence, due to the application of these relations, physical characteristics of porous materials effect must be investigated separately. in various constructed physical models of porous media, the effect of several variables such as ...

1 I n t r o d u c t i o n Piezoelectric transducers have been employed as sensors and transmitters of acoustic signals in ultrasound medical imaging, nondestructive testing and underwater acoustics (hydrophones). In this paper we consider the optimal design of a hydrophone composite consisting of parallel piezoceramic rods that are embedded in a porous polymer matrix. The hydrophone is assumed ...

AN ARTICLE by Belušič and Zupančič (1) described the construction of a finger pulse sensor using a singing greeting card beeper. We felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers, such as Pneumotrace (http:// www.adinstruments.com/prod...

This paper focuses on the development of the new BiScO3-PbTiO3 (BS-PT) based piezoelectric ceramic transducers for high-temperature SHM applications. By controlling the PbO deficiency in the material system, we modify the lossy ferroelectric properties and enhance the piezoelectric responses from the intrinsic BSPT. The new in-house fabricated piezoelectric transducers can maintain comparably h...

A “capacitive-piezo” transducer that combines the strengths of capacitive and piezoelectric mechanisms to achieve an impedance and Q simultaneously lower and higher, respectively, than otherwise attainable by either mechanism separately, has allowed demonstration of a 1.2-GHz contour-mode AlN ring resonator with a motional resistance of 889 Ω and Q=3,073 higher than so far measured for any othe...

In this paper an overview of functionally graded materials and constitutive relations of electro elasticity for three-dimensional deformable  solids is presented, and  governing equations of the Bernoulli–Euler and Timoshenko beam theories which account for through-thickness power-law variation of a two-constituent material and piezoelectric layers are developed  using the  principle  of virtua...

Based on the third-order shear deformation theory (TSDT), this paper numerically investigates the natural frequencies and time response of three-layered annular plate with functionally graded materials (FGMs) sheet core and piezoelectric face sheets, under initial external electric voltage. The impressive material specifications of FGM core are assumed to vary continuously across the plate thic...

Pressure-electric (hydrostatic piezoelectric) measurements are reported on bookshelf textures of a ferroelectric smectic-C (Sm C*) liquid crystal with a glass transition. The continuous variation of a partially fluid state to the solid glass enables one to trace how the piezoelectric effect depends on the consistency of the material. It was observed that in the Sm C* samples with poled glass th...