A strong acoustic field in a liquid separates the liquid and dissolved gases by the formation of bubbles (cavitation). Bubble growth and collapse is the result of active exchange of gas and vapor through the bubble walls with the surrounding liquid. This paper details a new approach to the study of cavitation, not as an evolution of discrete bubbles, but as the dynamics of molecules constituting both the bubbles and the fluid. We show, by direct, independent measurement of the liquid and the dissolved gas, that the motions of dissolved gas (freon-22, CHClF2 ) and liquid (water) can be quite different during acoustic cavitation and are strongly affected by filtration or previous cavitation of the solvent. Our observations suggest that bubbles can completely refresh their content within two acoustic cycles and that long-lived ( approximately minutes) microbubbles act as nucleation sites for cavitation. This technique is complementary to the traditional optical and acoustical techniques.
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http://dx.doi.org/10.1103/PhysRevE.78.066316 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506, United States.
Metal flux methods are excellent for synthesizing high-quality hexagonal boron nitride (hBN) crystals, but the atomic mechanisms of hBN nucleation and growth in these systems are poorly understood and difficult to probe experimentally. Here, we harness classical reactive molecular dynamics (ReaxFF) to unravel the mechanisms of hBN synthesis from liquid nickel solvent over time scales up to 30 ns. These simulations mimic experimental conditions by including relatively large liquid nickel slabs containing dissolved boron and a molecular nitrogen gas phase.
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January 2025
Hainan Key Laboratory of Storage & Processing of Fruits and Vegetables, Agricultural Products Processing Research Institute of Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China. Electronic address:
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View Article and Find Full Text PDFChemosphere
January 2025
Department of Civil and Environmental Engineering, Institute of Science Tokyo, Meguro-ku, Tokyo, 152-8552, Japan. Electronic address:
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January 2025
Department of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.
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View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA, 94305, USA.
Partial oxidation of methane (POM) is achieved by forming air-methane microbubbles in saltwater to which an alternating electric field is applied using a copper oxide foam electrode. The solubility of methane is increased by putting it in contact with water containing dissolved KCl or NaCl (3%). Being fully dispersed as microbubbles (20-40 µm in diameter), methane reacts more fully with hydroxyl radicals (OH·) at the gas-water interface.
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