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A high-power multifrequency ultrasonic actuator is proposed and characterized. The actuator is used in many applications as a multifrequency ultrasound power generator, but also as a mirror with variable bend radius to deflect laser beams in optical applications.

The performance of laser Doppler vibrometer (LDV) for ultrasonic waveform measurements in physical model experiments that are used for modeling seismic observations is evaluated. The coincidence of radial and transverse stress values have shown the validity of waveform measurements and the results have shown that LDV is applicable for measuring the 3-D particle-velocity at frequencies up to 0.5 MHz.

The article talks about the ultrasonic shear reflectance method, which employs the complex reflection coefficient at a solid-liquid interface for measuring the viscosity of the Newtonian liquids. The approach is shown to prove the existence of a Newtonian behavior in the less viscous liquids and a non-Newtonian behavior in the more viscous liquids.

The article explains and compares the envelope and cepstral methods, which are used for the in vitro and in vivo ultrasonic determination of the cortical bone thickness. The methods are shown to be widely used in various clinical applications, including osteoporosis screening.

The design and realization of an adaptive sound-shielding system based on a method to control the effective elastic stiffness of piezoelectric materials is presented. The acoustic pressure level of the transmitted sound in the system could be considerably reduced by appending an additional digital control circuit to the negative capacitor.

A soft computing approach is presented for the implementation of a suitable classifier for real-time applications. Results suggest that the proposed approach accurately discriminates defect in local areas.

The use of ultrasound in air as a means of communicating digital signals is discussed. Findings reveal the capability of binary phase shift keying (BPSK) in transmitting signals with a low bit error rate.

The regularization results of displacement vector measurements by multidimensional cross-spectrum phase gradient method (MCSPGM), multidimensional autocorrelation method (MAM) and multidimensional Doppler method (MDM) without lateral modulation are discussed. Better strain tensor measurement and shear modulus reconstruction is observed from the viewpoint of accuracy and stability.

A novel method connecting laser-based resonant ultrasound spectroscopy (RUS) with microscopic analysis of microstructural grain orientation is presented. Findings reveal the efficiency of the proposed method in determining the accuracy of averaged elastic constants for a polycrystalline material.

The numeric solutions to the linear wave equation and the parabolic wave equation are presented using finite difference and time-domain methods. Results when compared to Field II, a simulation package that is used to linearly model transducers in ultrasound, showed that the lateral beamplots and axial intensities are in good agreement with the Field II simulations.

A systematic analysis of the eigen-value problem associated with free, small-amplitude vibrations in an elastic body possessing piezoelectric, piezomagnetic, and magnetoelectric coupling is presented. Result shows a variational formulation and a perturbation analysis of the eigenvalue problem based on the abstract formation introduced.

An investigation is made regarding the singular behavior of charges at corner and edges on the metallized areas in SAW transducers. Results obtained from isotropic and anisotropic substrates for non-periodic configurations show that a tensor product of the of the Tchebychev bases overestimates the singularities at corners and thus cannot be used in a proper boundary element method formulation.

A theoretical study is conducted regarding the propagation properties of Lamb waves in a film loaded with different liquids on its two sides using two laser ultrasonic methods. Results showed that the proposed experiment techniques allow for an accurate characterization of Lamb mode propagation in a noncontact way.

The use of surrogate data algorithms for blind detection of nonlinearities in multiple-echo ultrasonic signals is analyzed by means of simulations. Results show that surrogate data technique is a potentially powerful tool for blind detection of nonlinearities in multiple-echo ultrasonic signals.

The dispersion curves of elastic waves propagating in electrical cables and in bare copper wires is validated experimentally and the model for calculating the velocity and attenuation of guided waves along copper wires based on Gazis equations formulated according to global matrix methodology is reported. Results show good agreement between the simulations and the experiments despite the peculiarities of electrical cables.

A study is made to focus on the critical aspects of the array elevation lens and to describe the in vivo experience with the multifunctional catheter in a novel intracardiac echocardiography (ICE) integration with 3-D anatomical mapping. It is seen that the combination of electroanatomical mapping and ICE would offer a significant means to improve the identification of therapeutic targets and decrease the dependency on potentially hazardous fluoroscopic guidance.

A study is done to determine the in-plane resonant vibration of angle-ply laminated composites embedded with a piezoceramic layer for different stacking angles using two experimental measurement techniques. Results show that the dynamic characteristics of in-plane resonant vibrations for piezolaminated plates with different stacking angles are very different.

An analysis for diffraction of sound by a fluid cylinder of elliptic cross section suspended in a Newtonian (viscous) fluid medium is presented. The study offers insight into the influence of the cylinder's cross-sectional ellipticity in addition to the viscous fluid effects on acoustic scattering, which increases on increasing the frequency in both viscous and ideal fluid situations.

In this paper, precise position control of a traveling-wave ultrasonic motor is achieved, avoiding the traditional drawbacks attributable to nonlinear torque generation, which are overshoot or slow response time. For that purpose, a behavior model control is proposed and presented. With this control law, a quick and precise response is obtained. In this paper, we present a position-control scheme of an inertial load. The guideline used for this control was a rotation of 90[degrees] in a response time of about 200 ms with a position error of 0.6 mrad, targeting a typical application for avionics. In this paper, a Shinsei USR30 is used, but the method can be applied to other ultrasonic motors. Index Terms--Causal modeling, control, piezoelectric, precision, ultrasonic.

A 64-kHz sandwich transducer employing a tube-shaped Terfenol-D/epoxy pseudo 1-3 magnetostrictive composite with 0.61 Terfenol-D volume fraction was developed to alleviate the intrinsic eddy-current losses in magnetostrictive alloy-based transducers. The transducer was designed to operate as a half-wave, longitudinal, mass-spring-mass, linear vibrator. It had a length of 15.7 mm and consisted of a magnetic circuit and a prestress mechanism. The magnetic circuit was composed of the composite tube, a pair of ring-shaped NdFeB permanent magnets, a drive solenoid, and a Ni-based magnetic flux guide. The distributions of the dc magnetic flux lines and magnetic field strength of the transducer were determined using an ANSYS finite-element model. The dynamic performance of the transducer was evaluated by measuring its electrical and vibrational characteristics. The results revealed that the transducer resonates at a frequency of 64.3 kHz with a strain coefficient of 39.2 nm/A, a mechanical quality factor of 39.6, and an effective coupling coefficient of 0.21. Eddy-current losses in the transducer were insignificant in the measured frequency range of 40 Hz-100 kHz. The good transducer performance indicated that Terfenol-D/epoxy pseudo 1-3 composites would be a promising magnetostrictive material for ultrasonic applications. Index Terms--Eddy-current losses, finite-element analysis, magnetostrictive composites, sandwich transducer, Terfenol-D, ultrasonics.

The high-resolution device of measuring local Young's modulus in very thin layers, which is the principle assessment parameter, is described. Experimental results revealed that Young's modulus was found to be higher in the dermis than in the hypodermis and other soft tissues.

The coupling liquid is used in the dry contact technique that transmits the ultrasound through a thin, solid layer, which is present between the coupling liquids. It is proven that along with the tested parts with an extra pressure of approximately 0.1 MPa, and realized the acoustic imaging of the interface in semiconductor equipments in dry contact situation.

Active cancellation of crosstalk effects in ultrasonic arrays is discussed. The approach makes use of the programmable transmitter waveform generators that are now being used with growing prevalence in diagnostic ultrasound systems.

The dynamic behavior and the performance characteristics of the disk type traveling wave piezoelectric ultrasonic motors (USM) are analyzed using impedance matrices. A comparison is made between the impedance matrix model and the three dimensional finite element model of the piezoelectric stator.

A single-transducer backscatter configuration technique measures the absolute attenuation and absolute backscatter coefficient of a tissue-mimicking gelatin phantom as a function of frequency. The method removes system-dependent ultrasonic effects. The phantom contains a random distribution of two populations of scatterers, and a spherical autocorrelation model uses the backscatter coefficients to estimate the size of scatterers. The experimental results for the magnitude and the frequency dependence of three transducers agree with theoretical predictions.

A study of the impact of several imaging parameters on ultrasonic displacement and velocity estimates revealed that the accuracy of these parameters were higher in porcine muscle samples than in porcine liver samples. Factors such as the magnitude and direction of target motion, target region, dimensions, ultrasonic frequency of interrogation and digital sampling frequency influenced the accuracy of ultrasonic displacement and velocity estimates.

Unfocused pulsed ultrasound spatial pressure distributions and intensity are studied. A 3.8 cm diameter PZT-4 transducer with 2MHz center frequency produces the ultrasound field. The unfocused pulsed intensity maxima is predicted to occur away from the beam axis in an asymmetric peak. Ultrasound distribution has to be measured on transverse planes, in addition to an axial plane.

We present a new image-based technique to rigidly register intraoperative three-dimensional ultrasound (US) with preoperative magnetic resonance (MR) images. Automatic registration is achieved by maximization of a similarity measure which generalizes the correlation ratio, and whose novelty is to incorporate multivariate information from the MR data (intensity and gradient). In addition, the similarity measure is built upon a robust intensity-based distance measure, which makes it possible to handle a variety of US artifacts. A cross-validation study has been carried out using a number of phantom and clinical data. This indicates that the method is quite robust and that the worst registration errors are of the order of the MR image resolution. Index Terms--Correlation ratio, image registration, magnetic resonance, robust estimation, ultrasound.

The authors Wu et al. failed to resolve the problems associated with the position-dependent changes in sensor sensitivity for fiber optic ultrasonic sensors. According to them, the effects of the ultrasound on the light beam ranges from light deflection, through Raman-Nath regime, to the transition regime approaching Bragg diffraction for ranges of 3-15 MHz. The reason of its fallout is discussed.