When Bubbles Are Not Spherical: Artificial Intelligence Analysis of Ultrasonic Cavitation Bubbles in Solutions of Varying Concentrations

Abstract

Ultrasonic irradiation of liquids, such as water− alcohol solutions, results in cavitation or the formation of small bubbles. Cavitation bubbles are generated in real solutions without the use of optical traps making our system as close to real conditions as possible. Under the action of the ultrasound, bubbles can grow, oscillate, and eventually collapse or decompose. We apply the mathematical method of separation of motions to interpret the acoustic effect on the bubbles. While in most situations, the spherical shape of a bubble is the most energetically profitable as it minimizes the surface energy, when the acoustic frequency is in resonance with the natural frequency of the bubble, shapes with the dihedral symmetry emerge. Some of these resonance shapes turn unstable, so the bubble decomposes. It turns out that bubbles in the solutions of different concentrations (with different surface energies and densities) attain different evolution paths. While it is difficult to obtain a deterministic description of how the solution concentration affects bubble dynamics, it is possible to separate images with different concentrations by applying the artificial neural network (ANN) algorithm. An ANN was trained to detect the concentration of alcohol in a water solution based on the bubble images. This indicates that artificial intelligence (AI) methods can complement deterministic analysis in nonequilibrium, near-unstable situations.

Machine learning for soft and liquid molecular materials

“…9d). 103 Pretrained CNNs with frozen layers can be successfully used for efficient model training without requiring a large dataset.…”

Automatic image processing of cavitation bubbles to analyze the properties of petroleum products

“…In addition to analyzing parameters such as soundwave propagation speed, 4,5 bubble size, and shape, [7][8][9][10] cavitation has been employed to estimate liquid's physical properties and composition. 7,11,12 Cavitation involves localized pressure changes that lead to the formation of bubbles composed of gas dissolved in a liquid and vapors of the solvent itself. For the evaluation of cavitation activity, the acoustic signal emitted by a sonotrode is transformed into an electric signal, which is then measured at a specic distance within the medium under investigation.…”

“…The bubble collapse is a very rapid process oen leading to shock waves, very high local temperatures and high pressures, as well as to uorescence. 7 While behavior close to instability is difficult to predict by traditional deterministic methods, oscillating and collapsing bubbles can provide large amounts of datasets (e.g., visual images), which make them an almost ideal object for articial intelligence (AI) and machine learning (ML) analyses and searches for correlations in data. 23 ML also enables efficient realtime object tracking [24][25][26][27] which is signicant for bubble behavior description.…”

“…The ANN was trained to determine the composition of these solutions based on the bubble images. 7 In the present study, we will use a segmentation model with bubble properties automatically determined from visual images to further expand that approach and apply it to petroleum products. We will discuss the changes in cavitation activity and explore new applications for analyzing selected samples of gasoline with different octane numbers (ONs) (92, 95, and 98).…”

Microbubbles Stabilized by Protein Shell: From Pioneering Ultrasound Contrast Agents to Advanced Theranostic Systems

“…An MB shell is mainly stabilized with lipids, proteins, or polymers [17][18][19][20][21][22][23][24]. Shell composition primarily affects MB performance regarding storage stability, circulation time, and stimuli response [25][26][27][28][29]. While lipid-based soft shell MBs are preferred for US imaging due to their optimal MB oscillation and resulting contrast profile; still, the gas can intensively diffuse, shortening MB stability.…”