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Ultrasound Intensity Exposimetry in Physiotherapy Devices using Micro-Bubbles
, M.Sc. Thesis Sharif University of Technology ; Zahedi, Edmond (Supervisor)
Abstract
Routine ultrasound calibration methods have some restrictions such as: low bandwidth, low frequency resolution, limited spatial resolution, the high cost of test and risk of damage to the transducer when exposed to high powers. In this thesis, a new technique based on microbubble resonance is proposed. Non-linear resonating microbubbles produce harmonics;the first harmonic may be masked by reflection from larger microbubbles as well as unwanted reflections which cause ambiguity in the determination of the amplitude of the excited pressure. Therefore, the second harmonic is used, with a single characteristic peak. In order to model the physical phenomenon, the second harmonic generated in the...
Drug delivery and adhesion of magnetic nanoparticles coated nanoliposomes and microbubbles to atherosclerotic plaques under magnetic and ultrasound fields
, Article Engineering Applications of Computational Fluid Mechanics ; Volume 15, Issue 1 , 2021 , Pages 1703-1725 ; 19942060 (ISSN) ; Ebrahimi, S ; Shamloo, A ; Boroumand, A ; Mofrad, M. R. K ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
The use of external fields such as magnet and ultrasound to enhance the targeted drug delivery (TDD) by nano-microcarriers could be a potential method. In this research, the drug delivery of magnetic nanoparticles (NPs) coated nanoliposomes and microbubbles (MBs) to the atherosclerosis plaque was investigated under magnetic and ultrasound fields in terms of their adhesion to the plaque through ligand–receptor binding. The Halbach arrangement enhanced the surface density of nanoliposomes and MBs adhered to the plaque by ∼ (Formula presented.) and ∼ (Formula presented.), respectively. A focused transducer at the power of (Formula presented.) led to better drug delivery performance and caused ∼...
Drug delivery and adhesion of magnetic nanoparticles coated nanoliposomes and microbubbles to atherosclerotic plaques under magnetic and ultrasound fields
, Article Engineering Applications of Computational Fluid Mechanics ; Volume 15, Issue 1 , 2021 , Pages 1703-1725 ; 19942060 (ISSN) ; Ebrahimi, S ; Shamloo, A ; Boroumand, A ; Mofrad, M. R. K ; Sharif University of Technology
Taylor and Francis Ltd
2021
Abstract
The use of external fields such as magnet and ultrasound to enhance the targeted drug delivery (TDD) by nano-microcarriers could be a potential method. In this research, the drug delivery of magnetic nanoparticles (NPs) coated nanoliposomes and microbubbles (MBs) to the atherosclerosis plaque was investigated under magnetic and ultrasound fields in terms of their adhesion to the plaque through ligand–receptor binding. The Halbach arrangement enhanced the surface density of nanoliposomes and MBs adhered to the plaque by ∼ (Formula presented.) and ∼ (Formula presented.), respectively. A focused transducer at the power of (Formula presented.) led to better drug delivery performance and caused ∼...
Experimental Study of Microbubbles Generation as a Contrast Agent in Blood, to Determine the Blood Flow by Echo-PIV Method
, M.Sc. Thesis Sharif University of Technology ; Shafiee, Behshad (Supervisor)
Abstract
Today microbubbles are broadly used as ultrasound contrast agents. These bubbles enhance the image resolution of B-mode pictures. Flow focusing in microchannels could provide us the goal of one-size bubbles generation. Microbubbles could use as tracers in Echo_PIV method to determine the velocity profile in main body vessels such as carotid. In this paper we introduce a new production method to fabricate a low-cost microchannel for preparing Microbubble contrast agents (less than 50 microns) by using some surface active agents and a viscosity enhancing material to obtain appropriate Microbubbles with desired life time and stability for any in vitro infusion for velocity measurement. By...
An experimental review on microbubble generation to be used in echo-particle image velocimetry method to determine the pipe flow velocity
, Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 135, Issue 3 , Feb , 2013 , Paper No: FE-12-1217 ; 00982202 (ISSN) ; Shafii, M. B ; Shirani, S ; Sharif University of Technology
2013
Abstract
Microbubbles are broadly used as ultrasound contrast agents. In this paper we use a low-cost flow focusing microchannel fabrication method for preparing microbubble contrast agents by using some surface active agents and a viscosity enhancing material to obtain appropriate microbubbles with desired lifetime and stability for any in vitro infusion for velocity measurement. All the five parameters that govern the bubble size extract and some efforts are done to achieve the smallest bubbles by adding suitable surfactant concentrations. By using these microbubbles for the echo-particle image velocimetry method, we experimentally determine the velocity field of steady state and pulsatile pipe...
Observations on the dynamics of bubble cluster in an ultrasonic field
, Article Nonlinear Dynamics ; Volume 72, Issue 3 , 2013 , Pages 561-574 ; 0924090X (ISSN) ; Zahir, H ; Yahyavi, M ; Barzegar, A ; Mobadersani, F ; Sharif University of Technology
2013
Abstract
The dynamics driven interaction between the bubbles in a cavitation cluster is known to be a complex phenomenon indicative of a highly active nonlinear as well as chaotic behavior in ultrasonic fields. By considering the cluster of encapsulated microbubble with a thin elastic shell in ultrasonic fields, in this paper, the dynamics of microbubbles has been studied via applying the methods of chaos physics. Bifurcation, Lyapunov exponent, and time series are plotted with respect to variables such as amplitude, initial bubble radius, frequency and viscosity. The findings of the study indicate that a bubble cluster undergoes a chaotic unstable region as the amplitude and frequency of ultrasonic...
Plasma core at the center of a sonoluminescing bubble
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 87, Issue 1 , 2013 ; 15393755 (ISSN) ; Sadighi Bonabi, R ; Sharif University of Technology
2013
Abstract
Considering high temperature and pressure during single bubble sonoluminescence collapse, a hot plasma core is generated at the center of the bubble. In this paper a statistical mechanics approach is used to calculate the core pressure and temperature. A hydrochemical model alongside a plasma core is used to study the bubble dynamics in two host liquids of water and sulfuric acid 85 wt % containing Ar atoms. Calculation shows that the extreme pressure and temperature in the plasma core are mainly due to the interaction of the ionized Ar atoms and electrons, which is one step forward to sonofusion. The thermal bremsstrahlung mechanism of radiation is used to analyze the emitted optical energy...
Ultrasound dosimetery using microbubbles
, Article IFMBE Proceedings, 20 June 2011 through 23 June 2011 ; Volume 35 IFMBE , June , 2011 , Pages 359-362 ; 16800737 (ISSN) ; 9783642217289 (ISBN) ; Zahedi, E ; Tavakkoli, J ; Sharif University of Technology
2011
Abstract
In this paper, a new technique based on nonlinear resonance of microbubbles is investigated in order to estimate the amplitude of an ultrasound wave pressure field. First, the existing theoretical model is reviewed. Then, an experimental setup consisting of a bubble generator and transmitting/receiving ultrasound transducers operating in the 1 MHz frequency range is described. The effect of background noise is also taken into account. Results show that the second harmonic oscillations are detectable, paving the way to develop a quantitative method for in vivo calibration of ultrasound waves
Herschel-Bulkley rheological parameters of lightweight colloidal gas aphron (CGA) based fluids
, Article Chemical Engineering Research and Design ; Volume 93 , 2015 , Pages 21-29 ; 02638762 (ISSN) ; Arabloo, M ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
Institution of Chemical Engineers
2015
Abstract
The proper understanding of rheological characteristics of CGA based fluids is of crucial importance in determining the performance of the fluid, in order to maintain the most effective fluid properties for safe, efficient, and economical drilling operation. This paper presents a concise investigation on the effect of concentration of the three main components of a novel environmentally friendly lightweight CGA based drilling fluid, i.e., xanthan gum biopolymer, starch, and biosurfactant, to the Herschel-Bulkley rheological model parameters. The three parameters of Herschel-Bulkley model, i.e., yield stress, fluid consistency, and fluid flow index were calculated by fitting the experimental...
Analysis of the Ultrasonic Cavitation on the Cancer Tumors
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Fallah Rajabzadeh, Famida (Supervisor)
Abstract
A complete understanding of high-intensity focused ultrasound-induced temperature changes in tissue requires insight into all potential mechanisms for heat deposition. Applications of therapeutic ultrasound often utilize acoustic pressures capable of producing cavitation activity. Recognizing the ability of bubbles to transfer acoustic energy into heat generation, a study of the role bubbles play in tissue hyperthermia becomes necessary. These bubbles are typically less than 50μm.
This dissertation examines the contribution of bubbles and their motion to an enhanced eating effect observed in a tissue-mimicking phantom. A series of experiments established a lationship between bubble...
This dissertation examines the contribution of bubbles and their motion to an enhanced eating effect observed in a tissue-mimicking phantom. A series of experiments established a lationship between bubble...
The dependence of the moving sonoluminescing bubble trajectory on the driving pressure
, Article Journal of the Acoustical Society of America ; Volume 126, Issue 5 , 2009 , Pages 2266-2272 ; 00014966 (ISSN) ; Rezaei Nasirabad, R ; Galavani, Z ; Sharif University of Technology
2009
Abstract
With a complete accounting of hydrodynamic forces on the translational-radial dynamics of a moving single-bubble sonoluminescence, temporal evolution of the bubble trajectory is investigated. In this paper, by using quasi-adiabatic evolution for the bubble interior, the bubble peak temperature at the bubble collapse is calculated. The peak temperature changes because of the bubble translational motion. The numerical results indicate that the strength of the bubble collapse is affected by its translational movement. At the bubble collapse, translational movement of the bubble is accelerated because of the increase in the added mass force on the bubble. It is shown that the magnitude of the...
Drug delivery performance of nanocarriers based on adhesion and interaction for abdominal aortic aneurysm treatment
, Article International Journal of Pharmaceutics ; Volume 594 , 2021 ; 03785173 (ISSN) ; Vatani, P ; Amani, A ; Shamloo, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Targeted drug delivery using nanocarriers (NCs) is one of the novel techniques that has recently been used to improve drug delivery to the Abdominal aortic aneurysm (AAA) disease. The purpose of this study is to evaluate the surface density of NCs (SDNC) adhered via ligand-receptor binding to the inner wall of AAA. For this purpose, fluid–structure interaction (FSI) analysis was first performed for the patient-specific and ideal AAA models. Then, by injecting NCs into the aortic artery, the values of SDNC adhered to and interacted with AAA wall were obtained. Two types of NCs, liposomes, and solid particles in four different diameters, were used to investigate the effect of the diameter and...
Monitoring the role of polymer and surfactant concentrations on bubble size distribution in colloidal gas aphron based fluids
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 556 , 2018 , Pages 93-98 ; 09277757 (ISSN) ; Kazemzadeh, E ; Kamari, E ; Ghazanfari, M. H ; Soleymani, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Colloidal gas aphron (CGA) based fluids have recently been introduced to develop depleted hydrocarbon reservoirs due to their ability in controlling fluid losses. Bubbles size of CGAs plays an important role in pore blockage ability as the controlling mechanism in fluid invasion reduction. However, fundamental understanding of how bubble size distribution is controlled by polymer and surfactant concentrations is not well discussed in the available literature. Almost all reported experiences on CGAs sizing were conducted on single bubble behavior, and little attention has been given to the variation of bubble size distribution (BSD) of CGAs at different levels of polymer/surfactant...