Showing papers in "Ultrasonics in 2011"

TL;DR: Full wavefield measurements obtained with either an air-coupled transducer mounted on a scanning stage or a scanning laser vibrometer can be combined with effective signal and imaging processing algorithms to support characterization of guided waves as well as detection, localization and quantification of structural damage.

TL;DR: The principal objectives of this work were to investigate the possibility of applying ultrasonic vibrations in the micro-forming process, to design a set of tooling for ultrasonic micro-extrusion and to observe experimentally how ultrasonic oscillations influences the forming load and the surface finish.

TL;DR: It is shown that LIPUS intensities lower than the current clinical standard have a positive effect on osteogenic differentiation of rat bone marrow stromal cells and the increased mineralization at lower intensities might be the first step towards redefining the most effective LIP US intensity for clinical use.

TL;DR: The presence of a crack-like defect on the sheet can be detected by either a sudden change in the ultrasonic waveform or by an enhancement in the frequency content of the waveform when the laser beam illuminates directly onto the crack.

TL;DR: The method allows the extraction of propagating modes only and, in spite of not producing continuous dispersion curves, it is not susceptible to aliasing effects, as some similar methods are.

TL;DR: The effective elliptical motion trajectory of the contact point of the stator can be achieved by the isosceles triangular structure part using only two PZTs, and thus it makes the motor low cost in fabrication, simple in structure and easy to realize miniaturization.

TL;DR: Results from experiments indicate that the new objective function and source location algorithm have improved performance when compared with those discussed in Refs.

TL;DR: The most effective process is formation of microjets, which can not only decrease diffusion layer thickness under 1 lm, but also activate (depassivate) electrode surface.

TL;DR: A new method for classifying the thyroid nodules based on the ultrasound (US) elastography features has the potential to substantially reduce the number of FNA biopsies by detecting benign nodules and managing them via follow-up observations rather than an FNABiopsy.

TL;DR: Improved GVF and balloon snake can be automatically initialized and overcome the problem caused by local energy minima and be validated for intravascular ultrasound images.

TL;DR: From the time-intensity curve analysis it was found that rise time of the bolus time- intensity curve is the least variable of all the studied time-ensity curve parameters.

TL;DR: This paper compares the results obtained from the surface wave method and the static spherical indentation method on five gelatin phantoms of different concentrations to show that both methods produce the same values for shear elasticity.

TL;DR: The TR-NEWS polar B-scan of the tooth is described and suggested as a potential application for modern echodentography and constitutes the basis of the self-consistent harmonic imaging sonography for monitoring cracks propagation in the dentine, responsible of human tooth structural health.

TL;DR: Longitudinal and transverse wave attenuation coefficients are obtained in a simple integral form for ultrasonic waves in cubic polycrystalline materials with elongated grains and reduce to the classic dependences of attenuation on parameters for polycrystals with equiaxed grains.

TL;DR: It is demonstrated thatMB-mediated sonodynamic action significantly induced apoptosis of HO-8910 cells and an increase in intracellular ROS level indicates that apoptosis is an important mechanism of cell death induced by MB-mediated SDT.

TL;DR: It is suggested that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood.

TL;DR: The analytical model is constructed by the generalization of the synthetic theory of plastic deformation, and a new term, ultrasonic defect intensity, is being introduced so that the phenomenon of both hardening and softening is described by the uniform system of constitutive equations.

TL;DR: The displacement amplification of the proposed horn is 71% higher than that of the traditional catenoidal horn with the same length and end surface diameters, and the harmonic response of the fabricated horn confirm the effectiveness of the design method.

TL;DR: It is noticed that the damping of vibrations and phase velocities of circumferential surface wave modes significantly depend on thermal relaxation time in addition to thermoelastic coupling in circular plates under resonance conditions.

TL;DR: The preliminary results indicate that the reference phantom algorithm could potentially provide an important diagnostic tool for diagnose symptoms prior to uterine contractions and the risk of premature delivery.

TL;DR: The cumulative second-harmonic of ultrasonic Lamb waves has been found to be strongly sensitive to the precipitates behavior and microstructure evolution during the thermal ageing of ferritic Cr-Ni alloy steel.

TL;DR: An ultrasound image guided and surface wave based method is proposed to measure regional lung surface wave speed and estimate lung elasticity noninvasively and these values fall well within the range of available literature.

TL;DR: High-frequency ultrasound transducers were fabricated and a bandwidth of 76.4% has been achieved with an insertion loss of -26dB and applications in high resolution biological and medical imaging could be possible with this lead-free material.

TL;DR: Results using a commercial ultrasound scanner modified to allow imaging in both grayscale and subharmonic mode should improve the applicability of SHI as a future primary clinical imaging modality.

TL;DR: Parametric studies on the phase velocity yield three main conclusions: the mechanical imperfection may remarkably reduce the phase Velocity, depending on the combination of the values of the wavenumber and the thickness ratio, and the piezoelectric and piezomagnetic stiffening can increase thephase velocity.

TL;DR: The results indicate that the self-made microbubbles effect on right ventricular hemodynamics is equivalent to that of normal saline at the same volume needed for effective enhanced imaging, demonstrating that it does not produce changes inright ventricular blood pressure under the study conditions.

TL;DR: A mean sound speed estimation method where phase variance of radio-frequency channel data in the region of interest is evaluated is presented and indicates that it could enhance the spatial and contrast resolution in the medical ultrasound imaging systems.

TL;DR: The full-wave solution for the wave propagation at the surface of media with arbitrary symmetry (including cubic and hexagonal symmetries) is obtained using two spectral numerical modeling algorithms.

TL;DR: It is found that these nanoparticles dispersed in PAO can undergo reversible, melting-freezing phase transition, and exhibit a relatively large hysteresis.

TL;DR: This study performs fundamental experiments on a closed fatigue crack formed in an aluminum alloy compact tension (CT) specimen using the proposed subharmonic phased array for crack evaluation (SPACE) method and shows that this method is useful in extracting only the intensity change of responses related to closed cracks, while canceling the responses of objects other than cracks.