The acoustic ducting effect by curved nonlinear gravity waves in shallow water is studied through idealized models in this paper. The internal wave ducts are three-dimensional, bounded vertically by the sea surface and bottom, and horizontally by aligned wavefronts. Both normal mode and parabolic equation methods are taken to analyze the ducted sound field. Two types of horizontal acoustic modes can be found in the curved internal wave duct. One is a whispering-gallery type formed by the sound energy trapped along the outer and concave boundary of the duct, and the other is a fully bouncing type due to continual reflections from boundaries in the duct. The ducting condition depends on both internal-wave and acoustic-source parameters, and a parametric study is conducted to derive a general pattern. The parabolic equation method provides full-field modeling of the sound field, so it includes other acoustic effects caused by internal waves, such as mode coupling/scattering and horizontal Lloyd's mirror interference. Two examples are provided to present internal wave ducts with constant curvature and meandering wavefronts.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1121/1.4770240 | DOI Listing |
J Clin Med
December 2024
2nd Department of Ophthalmology, Attikon Hospital, National and Kapodistrian University of Athens, 12462 Athens, Greece.
: Retinal vein occlusion (RVO) is a relatively uncommon condition with a complex pathophysiology. However, its association with traditional cardiovascular risk factors is well established. In this study, we compared arterial stiffness and endothelial function between patients with RVO and healthy controls.
View Article and Find Full Text PDFJ Clin Med
December 2024
Department of Pharmacology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, Jordana 38 St., 41-800 Zabrze, Poland.
Cardiovascular diseases (CVDs) are one of the most critical public health problems in the contemporary world because they are the leading cause of morbidity and mortality. Diabetes mellitus (DM) is one of the most substantial risk factors for developing CVDs. Glycated hemoglobin is a product of the non-enzymatic glycation of hemoglobin present in erythrocytes.
View Article and Find Full Text PDFDiagnostics (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 PDFInt J Equity Health
January 2025
Institute of Health Policy, Management & Evaluation, Dalla Lana School of Public Health, University of Toronto, 582-155 College Street, Toronto, ON, M5T 3M7, Canada.
Background: Internal migrants in China have long been at a disadvantage in terms of access to publicly financed services, as well as the utilization of public health services. The aim of the study was to examine inequities in the use of basic public health services between internal migrants and the local population and estimate the factors that contributed to inequity in use.
Methods: The data for this study was derived from the 2017 wave of the China Migrants Dynamic Survey.
J Magn Reson Imaging
January 2025
Department of Neurology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Background: Central arterial stiffening is associated with brain white matter (WM) damage and gray matter (GM) volume loss in older adults, but little is known about this association from an adult lifespan perspective.
Purpose: To investigate the associations of central arterial stiffness with WM microstructural organization, WM lesion load, cortical thickness, and GM volume in healthy adults across the lifespan.
Study Type: This is a cross-sectional study.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!