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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 numerical simulation method for a supersonic chemical oxygen-iodine laser is developed. The model is a combination of a three-dimensional computational fluid dynamics code without kinetics and a detailed one-dimensional, multiple-leaky-stream-tubes kinetics code. In the proposed method, the detailed flowfield characteristic is calculated by solving a full Navier-Stokes equation that does not involve chemical reactions, and the resultant temperature, velocity, and mixing characteristics are input to the kinetics code as its boundary conditions. A 'nonuniform coefficient' is introduced to transform the fluid-dynamic mixing to the diffusive mixing term of the kinetics code. As a result, precise predictions of the gain distribution and laser output are given with a reasonable computational cost. The developed model is applied to the X-wing-type supersonic mixing chemical oxygen-iodine laser, which we have developed, and the calculated gain and output power are compared with the experimental results. The excellent agreements of calculated and experimental results show the validity of the developed method.

The paper describes an experimental technique combining optical interferometry and ultrasonic attenuation to measure the bulk modulus (compressibility) and film thickness profiles of oil and grease films entrapped between a stationary steel ball and a sapphire plate. Results are presented for lithium- and urea-based greases, and their base oils alone, at contact pressures up to and around 3 GPa, and are compared with some models and results from other studies, extrapolated to the higher pressures achieved here. Results show that the bulk modulus of a particular grease and its base oil are found to be similar, at a given pressure, and largely dependent on the base-oil properties, which is demonstrated to be what is expected with the concentration levels of fillers and solid lubricants present. However, the film shapes measured for the grease and its base oil can be quite different. This is seemingly due to the manner in which the lubricant samples 'solidify', due to the high pressures, and also to the way in which the edges of the squeeze-film entrapped fluid are sealed. This latter sealing effect seems to be assisted by secondary phases, particularly with greases where fillers and solid lubricants are present, creating a very effective sealed contact where the entrapped lubricant samples could be observed to remain stable for several hours. [DOI: 10.1115/1.2125887]

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.

The ultrasonic pulse velocity technique was used to assess the structural integrity of timber elements in monumental buildings. Six species of timber of different strength values were selected to establish the pulse velocity ranges. The effect of moisture content, specific gravity, internal voids, and external voids on the pulse velocity was measured from tests on different samples. The pulse velocity perpendicular to the grain was found to increase with increase in specific gravity or compressive strength parallel to the grain. A correlation between compressive strength parallel to the grain and ultrasonic pulse velocity perpendicular to the grain was established from test results on six species of timber. A condition-rating system was developed to estimate the strength and to assess the extent of deterioration or the reduction in strength in timber beams. Tests on laboratory samples and extensive field studies on large timber joists and beams of a nearly 140-year-old church building suggest that the recommended procedure can be used effectively for in-service assessment (nondestructively) of wood.

Ultrasonics has become widespread as a nondestructive testing technique. The most commonly used device for generation and reception of ultrasound are contacting piezoelectric transducers. Because these devices require physical coupling with the sample, test specimens must be stationary, and surfaces both cool and nonabrasive. Obviously, traditional contacting transducers cannot be used for real-time evaluation of certain manufacturing operations, such as weld quality control where the test specimen could be in motion, and hot as well. This paper presents an evaluation of a noncontacting ultrasonic testing system consisting of a laser and fiber optic probe for generating ultrasound and an electromagnetic acoustic transducer for receiving the signals. This system has been applied to simulated liquid welds to demonstrate the feasibility of using similar equipment for real-time weld quality control. Weld penetration depth is investigated.

Ultrasonic vocalizations emitted by infant rodents are typically characterized as cries of distress. There are two contexts that are known to reliably elicit ultrasound production: extreme cold exposure and administration of clonidine, an (alpha)(sub 2) adrenoceptor agonist. Noting that these two contexts both entail pronounced decreases in cardiac rate, we have hypothesized that the vocalizations are acoustic by-products of a physiological maneuver, the abdominal compression reaction (ACR), that increases venous return to the heart when return is compromised. As a critical test of this hypothesis, we measured venous pressure near the right atrium in 15-day-old rats after clonidine administration. Consistent with the ACR hypothesis, emission of ultrasound was accompanied by large and reliable increases in venous pressure and, therefore, venous return. These results provide strong, direct support for the ACR hypothesis and, by doing so, underscore the potential pitfalls of anthropomorphic interpretations of the vocalizations of infant rats.

A theory of the excitation of ultrasound waves resulting from the photoelastic coupling with light was developed. Utilizing various reasonable approximations, a numerical computation of the transient stimulated Brillouin scattering procedure indicated that a large amplitude of acoustic wave can be constructed during the pulse of pump light and may damage the optical materials. This model provided a damage threshold of approximately 30-50 J/sq.cm. when applying Gaussian or square nanosecond pulses on optical materials.

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.

Investigation on the supersonic strut/endwall interactions in an annular duct showed good agreement between the experimental and numerical results. It showed that the effect of endwall curvature increases the interaction strength for concave walls and decreases the interaction strength for convex walls. Results also revealed the existence of horseshoe-type vortices seen at the struts' leading and trailing edges while corner vortices are seen at the junction of duct walls with both the compression and expansion faces.

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.

High pressure processing and ultrasound processing are two new methods being used by the food industry. High-pressure processing can accelerate microbial death rates especially if used with heat. Ultrsound can be used to dry foods rapidly if used with warm air though flavor may be affected with some products such as fruit drinks. Heat, ultrasound and pressure affects the heat resistance of some enzymes and microbes. This can also save energy by reducing the amount of heat needed.

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.

A multigram scale method facilitated the synthesis of enantiomerically-pure (Rp) and (Sp)-tertiary phosphine oxides. This method employed ultrasound irradiation to convert both (Rp)- and (Sp)-tert-butyl-phenylphosphinothioic acids into (Rp)- and (Sp)-tert-butylphenylphosphine oxides at room temperature when Raney-Ni was present. The secondary phosphine oxides were subsequently subjected to metalation and alkyl halide treatment.

Several nonlinear ultrasonic studies are conducted to explain the variation in strength caused by the precipitation characteristics of the system. The strength property is shown to be highly dependent on the precipitation phase transitions.

The thermally induced ultrasound emissions from printable semiconductor nanoparticles produced by the application of input pulses are shown on different substrates. The studies have shown that the emission efficiency is affected by the thermal effusivity of the nanoparticles, especially for the shell material in core-shell structured nanoparticles.