asymptotically exact and nonlocal third order nonlinear evolution equations are derivedfor two counterpropagating surface capillary gravity wave packets in deep water in thepresence of wind flowing over water.from these evolution equations stability analysis ismade for a uniform standing surface capillary gravity wave trains for longitudinal perturbation. instability condition is obtained and g...

introduction: in this study, a computer analysis method based on a block matching algorithm is presented to extract the longitudinal movement of the carotid artery wall using consecutive ultrasonic images. a window (block) is selected as the reference block in the first frame and the most similar block to the reference one is found in the subsequent frames. material and methods: the program was...

The angular dependence of the velocities of ultrasonic plane waves in a stressed, orthorhombic (orthotropic) continuum has recently been analyzed, and the results have been used to define scenarios for nondestructively measuring stress and preferred grain orientation [1,2]. These techniques make use of particular features which allow the two sources of anisotropy, stress and texture, to be sepa...

Asymptotically exact and nonlocal third order nonlinear evolution equations are derivedfor two counterpropagating surface capillary gravity wave packets in deep water in thepresence of wind flowing over water.From these evolution equations stability analysis ismade for a uniform standing surface capillary gravity wave trains for longitudinal perturbation. Instability condition is obtained and g...

Elastic wave scattering is used to study polycrystalline media for a wide range of applications. Received signals, which include scattering from the randomly oriented grains comprising the polycrystal, contain information from which useful microstructural parameters may often be inferred. Recently, a mode-converted diffuse ultrasonic scattering model was developed for evaluating the scattered r...

Poisson’s ratio has not received much attention because of its narrow range of measured values and difficulties in measurement. In previous work, genuine non-destructive evaluation method of characterizing weld-zone using Poisson’s ratio distribution was proposed. The method was to use immersion ultrasonic testing for measuring longitudinal and transverse wave speeds simultaneously. In present ...

Quantitative ultrasonic characterization of cancellous bone can be complicated by artifacts introduced by analyzing acquired data consisting of two propagating waves (a fast wave and a slow wave) as if only one wave were present. Recovering the ultrasonic properties of overlapping fast and slow waves could therefore lead to enhancement of bone quality assessment. The current study uses Bayesian...

Solid-state bonding methods, e.g., diffusion bonding and pressure welding, are becoming common manufacture and repair techniques for gas turbine engine components. Effective NDE inspection techniques are crucial to the utilization of this approach due to the high stresses on the bond plane associated with jet engine operation. Recently we have examined ultrasonic techniques for assessing bond q...

Guided wave focusing has been developed as a promising technique for defect detection in pipeworks, where non-axisymmetric flexural modes are tuned so that ultrasonic energy can be focused at a target point in a pipe. If a defect is located at the target point, large amplitude reflected waves can be observed. In this study, the focusing phenomenon is analyzed using a semi-analytical finite elem...