scholarly journals Cavitation Dynamics and Inertial Cavitation Threshold of Lipid Coated Microbubbles in Viscoelastic Media with Bubble–Bubble Interactions

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1125
Author(s):  
Dui Qin ◽  
Qingqin Zou ◽  
Shuang Lei ◽  
Wei Wang ◽  
Zhangyong Li
Keyword(s):  
Surface Tension ◽  
Bubble Dynamics ◽  
Surrounding Medium ◽  
Small Bubble ◽  
Initial Surface ◽  
Viscoelastic Media ◽  
Bubble Interactions ◽  
Inertial Cavitation ◽  
Cavitation Threshold ◽  
Bubble Oscillations

Encapsulated microbubbles combined with ultrasound have been widely utilized in various biomedical applications; however, the bubble dynamics in viscoelastic medium have not been completely understood. It involves complex interactions of coated microbubbles with ultrasound, nearby microbubbles and surrounding medium. Here, a comprehensive model capable of simulating the complex bubble dynamics was developed via taking the nonlinear viscoelastic behaviors of the shells, the bubble–bubble interactions and the viscoelasticity of the surrounding medium into account simultaneously. For two interacting lipid-coated bubbles with different initial radii in viscoelastic media, it exemplified that the encapsulating shell, the inter-bubble interactions and the medium viscoelasticity would noticeably suppress bubble oscillations. The inter-bubble interactions exerted a much stronger suppressing effect on the small bubble within the parameters examined in this paper, which might result from a larger radiated pressure acting on the small bubble due to the inter-bubble interactions. The lipid shells make the microbubbles exhibit two typical asymmetric dynamic behaviors (i.e., compression or expansion dominated oscillations), which are determined by the initial surface tension of the bubbles. Accordingly, the inertial cavitation threshold decreases as the initial surface tension increases, but increases as the shell elasticity and viscosity increases. Moreover, with the distance between bubbles decreasing and/or the initial radius of the large bubble increasing, the oscillations of the small bubble decrease and the inertial cavitation threshold increases gradually due to the stronger suppression effects caused by the enhanced bubble–bubble interactions. Additionally, increasing the elasticity and/or viscosity of the surrounding medium would also dampen bubble oscillations and result in a significant increase in the inertial cavitation threshold. This study may contribute to both encapsulated microbubble-associated ultrasound diagnostic and emerging therapeutic applications.

Inertial cavitation threshold dependence on high static pressures.

2010 ◽  
Vol 127 (3) ◽  
pp. 1984-1984
Author(s):  
Kenneth, B. Bader ◽  
Joel Mobley ◽  
Jason Raymond ◽  
D. Felipe Gaitan
Keyword(s):  
Inertial Cavitation ◽  
Cavitation Threshold

The Effect of Additives on Impregnated Diamond Bit Performance

1969 ◽  
Vol 9 (04) ◽  
pp. 425-433 ◽  
Author(s):  
A.A. Selim ◽  
C.W. Schultz ◽  
K.C. Strebig
Keyword(s):  
Mechanical Properties ◽  
Surface Tension ◽  
Crack Formation ◽  
Surrounding Medium ◽  
Drilling Process ◽  
Organic Additives ◽  
Rehbinder Effect ◽  
Mechanical Destruction ◽  
Effect Of Additives ◽  
Micro Cracks

Abstract The effect of some organic additives in diamond drilling of quartzite was investigated in the laboratory. The drill was designed to measure the rate of penetration, the trust, and the torque and to record penetration, the trust, and the torque and to record each as a function of the distance drilled. A statistical plan was followed throughout the investigation and an equation representing the bit performance was derived from the mathematical performance was derived from the mathematical theory to reliability. The drilling torque was found to increase with the use of additives while the sliding coefficient of friction and the wear coefficient decreased. The energy per unit volume consumed was found to increase with the use of additives. A hypothesis explaining the effects achieved with the additives is given. Introduction For some time researchers have attempted to increase drilling efficiency by adding certain agents to the flushing medium. Much of this interest is the result of the observations of Rehbinder, Shreiner and Zhigach. The postulate that "...in processes for the mechanical destruction of solids, a region of increased crack formation is created in the deformed layers adjoining the surface of destruction, forming the predestruction zone. The surrounding medium (for example, a liquid which wets a given solid will penetrate the embryo micro cracks of the predestruction penetrate the embryo micro cracks of the predestruction zone. Increasing the molecular affinity of this liquid for the surface of the solid considerably facilitates the deformation and destruction by softening the solid in the zone of increased crack formation. In this manner, the hardness or strength of the deformed body is decreased by the influence of the penetration of the liquid into the predestruction zone." This is known as the "Rehbinder effect". Rehbinder's work has prompted many investigators to examine the effect of additives on the mechanical destruction of rocks. Engelmann, Terichow and Selim reported that the maximum penetration of the rock by a diamond point in a solution environment was at the isoelectric point of the solution. Robinson reported that his point of the solution. Robinson reported that his results did not appear to support the theory of Rehbinder. Joris and McLaren suggested that additives with surface tension lower than water will be more efficient in cooling the diamonds. Their effectiveness in removing the fine cuttings from the face of the bit will also improve the efficiency of the system. They reported an improvement in impregnated bit life and penetration rates with the use of soluble oil additives. In contrast, Long and Agnew, drilling with surface set bits, reported that lubricating agents increase bit temperature and wear. A significant change was reported in the mechanical properties of rock with polar additives. It properties of rock with polar additives. It was concluded that this change in the mechanical properties of the rock in the presence of the additive properties of the rock in the presence of the additive is due to the rock hydrophilic properties. Ethylene glycol, glycerine and anionic detergent were selected for this investigation because their surface tension is lower than that of water. The surface tension of these additives for the concentrations studied was 42 to 75 percent of the surface tension of water. A low surface tension additive would wet the surface of the diamonds more easily and hence would be more effective in cooling the diamonds. Another characteristic of these low surface tension additives is their effectiveness in removing the cuttings and preventing the flocculation of the formed particles in the drilling process. This article summarizes the results of an investigation performed at the laboratories of USBM, Twin performed at the laboratories of USBM, Twin Cities Mining Research Center. The objective of the investigation was to study the over-all effects of some organic additives on the performance of diamond impregnated bits in atmospheric drilling conditions only and not in downhole pressured conditions. SPEJ p. 425

Nonlinear bubble dynamics in viscoelastic media

2003 ◽  
Vol 113 (4) ◽  
pp. 2193-2194
Author(s):  
Stanislav Y. Emelianov ◽  
Mark F. Hamilton ◽  
Yurii A. Ilinskii ◽  
Evgenia A. Zabolotskaya
Keyword(s):  
Bubble Dynamics ◽  
Viscoelastic Media

Investigation on the inertial cavitation threshold of micro-bubbles

2013 ◽  
Vol 133 (5) ◽  
pp. 3496-3496
Author(s):  
Xiasheng Guo ◽  
Dong Zhang ◽  
Juan Tu
Keyword(s):  
Inertial Cavitation ◽  
Cavitation Threshold

Bubble dynamics in a viscoelastic medium with nonlinear elasticity

2015 ◽  
Vol 766 ◽  
pp. 54-75 ◽  
Author(s):  
R. Gaudron ◽  
M. T. Warnez ◽  
E. Johnsen
Keyword(s):  
Soft Tissue ◽  
Nonlinear Elasticity ◽  
Viscoelastic Medium ◽  
Strain Energy ◽  
Bubble Dynamics ◽  
Surrounding Medium ◽  
Viscoelastic Model ◽  
Energy Functions ◽  
Newtonian Liquids ◽  
Strain Energy Functions

AbstractIn a variety of recently developed medical procedures, bubbles are formed directly in soft tissue and may cause damage. While cavitation in Newtonian liquids has received significant attention, bubble dynamics in tissue, a viscoelastic medium, remains poorly understood. To model tissue, most previous studies have focused on Maxwell-based viscoelastic fluids. However, soft tissue generally possesses an original configuration to which it relaxes after deformation. Thus, a Kelvin–Voigt-based viscoelastic model is expected to be a more appropriate representation. Furthermore, large oscillations may occur, thus violating the infinitesimal strain assumption and requiring a nonlinear/finite-strain elasticity description. In this article, we develop a theoretical framework to simulate spherical bubble dynamics in a viscoelastic medium with nonlinear elasticity. Following modern continuum mechanics formalism, we derive the form of the elastic forces acting on a bubble for common strain-energy functions (e.g. neo-Hookean, Mooney–Rivlin) and incorporate them into Rayleigh–Plesset-like equations. The main effects of nonlinear elasticity are to reduce the violence of the collapse and rebound for large departures from the equilibrium radius, and increase the oscillation frequency. The present approach can readily be extended to other strain-energy functions and used to compute the stress/deformation fields in the surrounding medium.

Effect of Surface Tension on the Cavitation Threshold of Water

1972 ◽  
Vol 52 (1A) ◽  
pp. 151-152 ◽  
Author(s):  
L. A. Crum ◽  
J. B. Gallemore ◽  
D. A. Nordling
Keyword(s):  
Surface Tension ◽  
Cavitation Threshold ◽  
Effect Of Surface
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