Showing papers in "Ultrasonics in 2021"

TL;DR: In this article, the importance of the f -number and speed of sound on image quality was discussed and a solution to set their values from a physical viewpoint was proposed, where the authors suggest determining the f-number from the directivity of the transducer elements and the speed-of-sound from the phase dispersion of the delayed signals.

TL;DR: In this paper, a review of the state-of-the-art SH wave transducers for structural health monitoring (SHM) and nondestructive testing (NDT) is presented.

TL;DR: A generic DCNN architecture with transfer learning and the same architectural parameter settings to train models for thyroid and breast cancers (TNet and BNet) respectively are proposed and the viability of such a generic approach with ultrasound images collected from clinical practices is tested.

TL;DR: A comprehensive review of recent studies on ultrasonic piezoelectric motors is presented in this article, where the authors focus on research articles published in the last five years mostly.

TL;DR: The feasibility of LU inspection of WAAM components without surface machining is verified by analyzing the A- and B-scan plots of different defects in the WAAM sample.

TL;DR: In this paper, the authors investigated the damage progression in reinforced concrete (RC) structures at different levels of damage using linear and nonlinear ultrasonic techniques, and found that the changes in linear parameters due to damage progression are often insignificant and inconsistent.

TL;DR: In this paper, a robust strategy including the high-resolution extraction of the multimodal dispersion curves and model-based elastic property estimation is presented, which can be implemented with ease and few parameters need to be tuned.

TL;DR: In this article, an optimized softmax classifier is proposed based on the traditional softmax classification, and the convolution neural network (CNN) framework is built, which can achieve the accurate classification of signals with similar curves.

TL;DR: In this article, the backward combined harmonic, generated at difference frequency and propagating in the direction opposite to that of two primary co-directional guided waves, is successfully observed numerically.

TL;DR: It was verified that R-HUVC can be applied to high-speed machining for the finish turning of hardened steel because it improves the machining performance.

TL;DR: A flexible approach based on ultrasonic guided wave digital surrogates (i.e., numerical simulations of incident waves) and transfer learning is discussed and the comparison of the dictionary learning method with wavenumber filtering technique which is often used to enhance the defect wavefields is illustrated.

TL;DR: Comparison between the ray analysis and experimental results offers insight into the behaviour of this type of metasurface especially in the proximity of the acoustic bandgaps and highlights the possibility for acoustic shielding.

TL;DR: Experimental results demonstrate that the proposed automatic tumor segmentation method SC-FCN-BLSTM offered improved segmentation results compared with existing deep learning-based methods.

TL;DR: An overview of recent laboratory, field and mathematical studies to serve as reference for future extensive examination of ultrasound assisted improved oil recovery and research gaps and opportunities were identified.

TL;DR: In this article, the use of a kernel-based machine learning strategy targeting classification and regression tasks in view of automatic flaw detection, localization, and characterization is presented, where measured guided wave signals are post processed with a guided wave imaging algorithm in order to obtain an image representing the health of each specimen.

TL;DR: DSWE-Net is proposed, a novel deep learning-based approach that is able to construct Young's modulus maps from ultrasonically tracked tissue velocity data resulting from a single acoustic radiation force (ARF) push and shows its potential for use in real-world clinical practice.

TL;DR: The proposed artificial neural network based parameter estimation method of the HK distribution yielded comparable diagnostic performance to state-of-the-art HK estimators in the assessment of hepatic steatosis and has great potential in ultrasound tissue characterization based on theHK distribution.

TL;DR: This paper investigates a means to automate Lamb wave-based NDT by positioning sensors along a planar structure through mobile service robots such that an autonomous SLAM-capable NDT system can become realizable.

TL;DR: An ultrasonic aspirator with elliptical vibration on the end face is presented in this paper, which greatly increased the mechanical effect of the aspirator and exhibited a higher removal efficiency.

TL;DR: An analytical model is proposed for predicting the frequency, mode and direction of propagation of the mixed modes arising from the nonlinear mixing of two incident guided-wave modes at an interface exhibiting contact acoustic nonlinearity, demonstrating the existence of mixed waves and showing that interface mixing leads to a higher amplitude mixed wave than that due to the background material non linearity.

TL;DR: The theoretical and experimental verification of complete phononic band gaps in the Yablonovite structure with additional spheres in a face-centered cubic arrangement are presented.

TL;DR: The results demonstrate the feasibility of using the ultrasonic elastography system to investigate the stiffness mapping of posterior eye with high resolution in both increasing and decreasing IOPs, making this technique potentially useful for glaucoma.

TL;DR: In this article, defect zones in a curved composite structure are characterized using the modified probabilistic tomography (MPT) method and fusion of damage index (DI) for structural health monitoring of curved composite structures.

TL;DR: In this article, a multi-frequency localized wave energy is presented using laser ultrasonic guided waves for delamination identification, which is not only related to mode conversion caused by the decrease of structural thickness above the delamination, but also the scattering waves in delamination region.

TL;DR: In this paper, the rotational magnetic field oscillation and low-intensity sub-megahertz ultrasound stimulation of magnetic microbubbles (MMBs) were used to promote the nanodroplets phase transition and improve the permeation of NDs into the blood clot fibrin network to enhance the sonothrombolysis efficiency.

TL;DR: In this paper, linear ultrasound measurements are used to interrogate 420 stainless steel coupons from three manufacturing methods: wrought, AM, and hybrid AM (directed energy deposition+laser peening), and the results highlight the potential of ultrasound as an efficient and accessible non-destructive characterization method for hybrid AM samples and inform further nondestructive evaluation decisions in AM.

TL;DR: In this paper, the Faster R-CNN was used to identify, locate and size flat bottom holes (FBH) and side-drilled holes (SDH) in an immersed test specimen using a single plane wave insonification.

TL;DR: In this paper, a study of surface acoustic wave propagation in a damage layer with finite thickness and residual stress on an orthotropic semi-infinite medium was performed to reveal the application of laser ultrasound in the surface inspection of ground silicon wafers.

TL;DR: In this paper, an unsupervised clustering technique is used to discriminate nanometric metal disks patterned on a dielectric substrate. The analysis aims to recognize similarities among nanopatterned disks and to cluster them accordingly, each cluster is characterized by a fingerprint time-resolved trace.

TL;DR: In this paper, high-order Lamb wave modes in a dry human skull were investigated and characterized using a semi-analytical finite element model of an equivalent three-layered plate for the identification of wave modes based on their through-the-thickness profiles.