Acoustic gaps are normally observed in granular inhomogeneous structures made of composite materials. The modulation of the elastic properties in such media creates the coherent effects of scattering and interference that ultimately lead to frequency intervals where sound propagation is forbidden. Contrastingly, we report here an experimental observation of acoustic gaps in homogeneous media; specifically, in granular chains. The beads used in our study are magnetic. Therefore, instead of modulating the elastic properties of the chain, we modulate the magnetization (i.e., the contact forces). We also observe that the propagation speed of acoustic signals through the magnetic chains used in this study is at odds with the speed predicted by Hertz's law.
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http://dx.doi.org/10.1103/PhysRevE.81.011301 | DOI Listing |
Grey mullets (family Mugilidae) are widespread across coastal, brackish, and freshwater habitats, and have supported fisheries for millennia. Despite their global distribution and commercial value, little is known about their movement ecology and its role in the co-existence of sympatric mullet species. Gaps in knowledge about migratory behaviour, seasonal occurrence, and movement scales have also impeded effective management, highlighting the need for further research.
View Article and Find Full Text PDFProc Inst Mech Eng H
January 2025
Department of Medical Sciences & Technology, IIT Madras, Chennai, Tamil Nadu, India.
The use of ultrasound contrast agents (UCAs) for estimating portal pressure has recently gained attention due to its clinical promise, yet variability in acoustic amplitude poses challenges. UCAs contain microbubbles (1-10 µm in diameter), and understanding their acoustic response is essential to address this variability. However, systematic exploration of factors influencing microbubble behavior remains limited in current literature.
View Article and Find Full Text PDFChildren (Basel)
November 2024
Faculty of Medical Sciences, State University of Campinas, Campinas 13083-887, SP, Brazil.
Unlabelled: COVID-19 is an infectious disease caused by the SARS-CoV-2 virus. During and after COVID-19, audiovestibular symptoms and impairments have been reported.
Objectives: This study aimed to investigate the impacts of COVID-19 on the peripheral and central auditory systems of children and adolescents following the acute COVID-19 phase based on behavioral, electroacoustic, and electrophysiological audiological assessments.
Ultrason Sonochem
January 2025
Department of Family and Consumer Sciences, North Carolina Agricultural and Technical State University, Greensboro, NC 27411, USA. Electronic address:
Ultrasound technology has been increasingly explored as an eco-friendly method to improve the microbial safety of leafy greens. However, its effect on produce quality is critical, and considerable knowledge gaps remain in this area. The present study examined the response of leafy greens to ultrasound treatment as shown by tissue damage and sensory quality, using a novel multifrequency, multimode, modulated (MMM) system to address the issue of nonuniform ultrasound field distribution.
View Article and Find Full Text PDFNat Commun
January 2025
Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom.
Inorganic semiconductors based on heavy pnictogen cations (Sb and Bi) have gained significant attention as potential nontoxic and stable alternatives to lead-halide perovskites for solar cell applications. A limitation of these novel materials, which is being increasingly commonly found, is carrier localization, which substantially reduces mobilities and diffusion lengths. Herein, CuSbSe is investigated and discovered to have delocalized free carriers, as shown through optical pump terahertz probe spectroscopy and temperature-dependent mobility measurements.
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