The authors present a model to study ultrasound-induced cavitation dynamics in liquid carbon dioxide (CO(2)), which includes descriptions for momentum, mass, and energy transport. To assist in the interpretation of these results, numerical simulations are presented for an argon cavity in water. For aqueous systems, inertia effects and force accumulation lead to a nonlinear radial motion, resulting in an almost adiabatic compression of the cavity interior. The simulations for liquid CO(2) suggest that transport limitations impede nonlinear cavitation dynamics and the corresponding temperature rise. Consequently, in liquid CO(2) the ultrasound-induced formation of radicals appears improbable.
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http://dx.doi.org/10.1063/1.2434962 | DOI Listing |
Ultrason Sonochem
January 2025
Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy; Polito(BIO)Med Lab, Politecnico di Torino, 10129 Turin, Italy. Electronic address:
In the context of molecular imaging, the present work explores an innovative platform made of lipid-coated nanocrystals as contrast-enhanced agent for both ultrasound imaging and sonoluminescence. At first, the dynamics of gas bubbles generation and cavitation under insonation with either pristine or lipid-coated nanocrystals (ZnO-Lip) are described, and the differences between the two colloidal systems are highlighted. These ZnO-Lip show an unprecedented ability to assist cavitation, which is reflected in enhanced sonoluminescent light emission with respect to the pristine nanocrystals or the pure water.
View Article and Find Full Text PDFLangmuir
January 2025
Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, China.
Cavitation has been a hot research topic for scholars in various fields because of the intense mechanical, chemical, and thermal effects of bubble collapse. It forms a cluster of bubbles, and the bubbles will affect, interfere with, and couple with each other. To grasp the main factors affecting bubble collapse and the interbubble mechanism, the paper adopts the molecular dynamics simulation combined with the coarse-grained force field to study the collapse process of the double bubble model and takes the dynamic shape change of the bubbles, the local velocity distribution, and the local pressure distribution as the object to summarize the position angle, the shock velocity, and the bubble distance on the collapse law and the primary and secondary influence relationship and then reveals the interbubble mechanism.
View Article and Find Full Text PDFUltrason Sonochem
January 2025
Acoustic droplet vaporization (ADV) plays a crucial role in ultrasound-related biomedical applications. While previous models have examined the stages of nucleation, growth, and oscillation in isolation, which may limit their ability to fully describe the entire ADV process. To address this, our study developed an integrated model that unifies these three stages of ADV, stimulated by a continuous nonlinear dual-frequency ultrasound wave.
View Article and Find Full Text PDFUltrason Sonochem
January 2025
School of Engineering Computing and Mathematics, Oxford Brookes University, Oxford, UK; Department of Materials, University of Oxford, Oxford, UK.
This study experimentally investigates the role of cavitation-induced shock waves in initiating and destabilizing capillary (surface) waves on a droplet surface, preceding atomization. Acoustic emissions and interfacial wave dynamics were simultaneously monitored in droplets of different liquids (water, isopropyl alcohol and glycerol), using a calibrated fiber-optic hydrophone and high-speed imaging. Spectral analysis of the hydrophone data revealed distinct subharmonic frequency peaks in the acoustic spectrum correlated with the wavelength of capillary waves, which were optically captured during the onset of atomization from the repetitive imploding bubbles.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, 2199 Wesbrook Mall, Vancouver, British Columbia, V6T 1Z3, Canada.
Introduction: To evaluate the bacterial biofilm, smear layer and debris removal efficacy of a hydro-dynamic cavitation system with physiological saline using a new ex vivo model.
Methods: Seventy-five dentin discs were prepared from fifty-four extracted teeth. Seventy-five artificial root sockets were prepared.
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