Model equations with cubic nonlinearity are developed for a plane shear wave of finite amplitude in a relaxing medium. The evolution equation for progressive waves is solved analytically for a jump in stress that propagates into an undisturbed medium. Weak-shock theory is used to determine the amplitude and location of the shock when the solution predicts a multivalued waveform. The solution is similar to that obtained by Polyakova, Soluyan, and Khokhlov [Sov. Phys. Acoust. 8, 78-82 (1962)] for a compressional wave with quadratic nonlinearity in a relaxing fluid. Numerical simulations illustrate the effect of relaxation on shock formation in an initially sinusoidal shear wave. The minimum source amplitude required for an initially sinusoidal waveform to develop shocks in a relaxing medium is determined as a function of the dispersion and relaxation time. Limiting forms of the evolution equation are considered, and analytical solutions incorporating weak-shock theory are presented in the high-frequency limit. A Duffing-type model for a nonlinear shear-wave resonator is developed and investigated.
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http://dx.doi.org/10.1121/1.5023394 | DOI Listing |
Diagnostics (Basel)
December 2024
Department of Surgery, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
The accurate staging of liver fibrosis is crucial for managing chronic liver disease (CLD). Although magnetic resonance elastography (MRE) is the reference standard for noninvasive fibrosis assessment, its cost, specialized hardware, and operational demands restrict accessibility. In contrast, two-dimensional shear-wave elastography (2D-SWE) is more affordable, accessible, and widely integrated into routine ultrasound systems.
View Article and Find Full Text PDFDiagnostics (Basel)
December 2024
Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj 16278, Saudi Arabia.
Sonoelastography, a novel ultrasound-based technique, is emerging as a valuable tool in prenatal diagnostics by quantifying tissue elasticity and stiffness in vivo. This narrative review explores the application of sonoelastography in assessing maternal and fetal health, with a focus on cervical, placental, pelvic floor, and fetal tissue evaluations. In the cervix, sonoelastography aids in predicting preterm birth and assessing labor induction success.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
Department of Mechanics of Materials and Constructions (MeMC), Vrije Universiteit Brussel, B-1050 Brussels, Belgium.
There is very limited research in the literature investigating the way acoustic emission signals change when polymer materials are undergoing different fracture modes. This study investigates the capability of acoustic emission to recognize the fracture mode through acoustic emission parameter analysis, and can be considered the first-ever study which examines the impact of different loading conditions, i.e.
View Article and Find Full Text PDFAcad Radiol
January 2025
Department of Orthopedics and Traumatology, Samsun University Faculty of Medicine, Samsun, Turkey (A.E.O.).
Rationale And Objectives: This study aimed to evaluate the efficacy of ultrasound (US)-guided local steroid injection in carpal tunnel syndrome (CTS) using shear wave elastography (SWE).
Materials And Methods: A total of 47 wrists from 41 patients diagnosed with mild to moderate idiopathic CTS, based on clinical and electrophysiological criteria, were enrolled between June and October 2024. All participants underwent US-guided local steroid injection.
Med Sci Sports Exerc
December 2024
Department of Rehabilitation Sciences, Ghent University, Ghent, BELGIUM.
Purpose: Eccentric calf training for Achilles tendinopathy shows variable success in athletes. Recent insights suggest a role for tendon fluid flow (exudation or redistribution) during exercise, which explains post-exercise reductions in thickness and increases in stiffness of the tendon. This fluid flow is thought to be beneficial as it may promote tendon remodeling, reduce intratendinous pressure, and alleviate pain.
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