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Numerical Investigation of Droplet Generation in a Microfluidic Flow-Focusing Junction Aiming High-Throughput Droplet Generation
, M.Sc. Thesis Sharif University of Technology ; Taghipoor, Mojtaba (Supervisor) ; Hosseini, Vahid (Supervisor)
Abstract
Droplet microfluidic platform generates monodisperse droplets in a desired size through immiscible multiphase flows inside microchannels. Droplets are individual reactor and can be used for bio(chemical) analyses. Also, for materials fabrication, droplet microfluidics offers a versatile platform for generation of nano- or micro-sized particles and microcapsules that are widely used in drug delivery. In addition to the monodispersity, high-throughput generation is also necessary in many applications. Therefore, droplets must be formed in stable regimes (dripping and squeezing) in the highest possible frequency. In this study, the flow-focusing geometry, which is the most common geometry in...
Numerical Study of Enhancement of Inflection Point Focusing for Blood Cell Separation
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Sadrhosseini, Hani (Co-Supervisor)
Abstract
Today, the determination and therapy of numerous illnesses, including malignant growth, relies upon the information and assessment of platelets, so blood testing and cell examination is fundamental to survey the movement of disease. The lab on a chip innovation is utilized as an extremely productive device in cell studies. The lab on a chip is used as a foundation and a substrate for making a legitimate stream for cell processes in medication. This innovation is a gadget or framework with millimeters or centimeters aspects like a chip, and it performs research facility handling on a micron-scale. In spite of the fact that it has a few impediments, it has so many values; for example, it...
Numerical Modeling of Treatment of Liver Tissue Cancer by Using High Intensity Focused Ultrasound (Hifu)
, Ph.D. Dissertation Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
In recent years, the incidence rate of liver cancer has increased sharply and nowadays liver cancer is known as the second leading cause of cancer death in the world. Surgical resection is usually used to treat malignant hepatic tumors. However, in some cases, surgical resection is not possible because of some reasons, such as tumor size and location. In these cases, other minimally invasive ablation methods such as radio-frequency ablation, microwave ablation, and high intensity focused ultrasound (HIFU) can be used. HIFU has some advantages such as noninvasiveness, high penetration depth, and low cost in comparison to the other ablation techniques such as radiofrequency ablation. In HIFU...
Propagation Modeling of High Intensity Focused Ultrasound Wave through Multi Layer Tissue along with Experimental Validation
, Ph.D. Dissertation Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor)
Abstract
One of the main problems in human health, both in advanced societies and in growing societies, is a variety of cancers, one of which is brain tumor. One of the non-invasive methods of treating tumors is the use of ultrasound.HIFU (High Intensity Focused Ultrasound) therapy method is known as one of the most advanced surgical techniques in tumor ablation therapy. HIFU are produced and concentrated by powerful transducers. The two main mechanisms in HIFU are mechanical and thermal mechanisms, and the effects of these two mechanisms appear as thermal effects and cavitation. The fundamental mechanism in the HIFU is to absorb ultrasonic waves and to convert them into heat.The purpose of this...
Particle Focusing on a Lab on a Disk System
, M.Sc. Thesis Sharif University of Technology ; Shamloo, Amir (Supervisor)
Abstract
In many microfluidic devices, focusing particles into a narrow stream is usually an essential step prior to counting, detecting, and sorting them. By installation of microfluidic laboratory functions on a rotating disk, new devices called Lab-on-a-disks, which have plenty of advantages in comparison to ordinary Lab-on-a-chips, shape. In this study, to the best of our knowledge for the first time, a Lab-on-a-disk device is designed and fabricated in order to focus particles prior to detecting them by a conventional CD-ROM as a strong optical system. Hydrophoresis method, using slanted obstacles to induce transverse pressure gradients, is utilized to focus particles. In this regard, the...
Design & Prototyping of a Reflective Optical Hybrid Incremental-Absolute Encoder Based on Compact Disc Technology
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor)
Abstract
The reflective optical rotary encoders are used greatly in automation systems for speed and position measurements. Their approach of reading code as pulses which results in position and speed information is very similar to what a CD-ROM driver performs to read the saved data as pits and lands on the compact disc data layer. Moreover, the micron size of pits and lands in compact disc promise a high-resolution, and low cost rotary encoder based on CD-ROM technology. In this thesis, two concepts of length coding and hybrid incremental-absolute coded discs are proposed. To verify the implementation of these concepts, the rotary encoder set based on CD-ROM technology is designed and tested. It...
Design and Construction of a Bent Crystal Spectrometer for Studying Soft X-Rays of Sharif Plasma Focus
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Etaati, Gholam Reza (Supervisor)
Abstract
A soft X-ray spectrometer based on Johann's method and an embedded curved crystal is designed and fabricated for Sharif University of Technology's Plasma Focus (SUT-PF) in this project. Focusing rays with the same wavelength at a point to increase the ray intensity is the reason of choosing the cylindrical curved crystal spectrometer since its performance is inspired to the Bragg's law.The optimal conditions for SUT-PF (pressure and voltage) is adjusted and examined by photodiode detector and the camera pinhole before spectroscopy experiments. The diameter of generated hot spots is measured as 80 microns in the optimal condition.The recorded spectral lines on the radiography film and the...
Design, Simulation and Construction of a Microfluidic Device for the Purpose of Target Cells Separation and DNA Extraction
, M.Sc. Thesis Sharif University of Technology ; Shamloo, Amir (Supervisor) ; Nouri Borujerdi, Ali (Supervisor)
Abstract
Today, microfluidic experiments have found wide applications in medical sciences, engineering, and chemistry. Because of their small size, microfluidic devices help us to be able to use very little amount of sample for the experiments and also easily control and observe the under-experiment fluid. One of the most important applications of these devices is the separation of cancer cells in blood for counting their number and DNA genetic studies. In the current project we have tried to do the separation of cancer cells from other cells by designing an inertia microchannel. For this purpose, in the first step a geometry for the channel is designed with analyzing the induced forces on the cells....
Analysis and Modeling "Time-of-Flight Particle Sizer" with CFD
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mahdi (Supervisor)
Abstract
In this study different models of an aerodynamic particle sizer and aerodynamic focusing lens were introduced and governing equations for an aerodynamic focusing lens for flow fields and particle motions were discussed. An aerodynamic focusing lens was simulated for analyzing particle motions and flow fields. Two kinds of models are considered; One was Ahmadi`s model and the other one was Wang`s model and both models are axisymmetric. The results show that for small particles (sub 30 nanometers), Brownian motions were highly effective on transmission efficiency and producing particle beams. The two models are compared and the results show that Ahmadi`s model produce narrower particle beams...
Numerical Simulation of Flow Focusing Injectors for Liquid Microjet
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
One of the key features of multiphase flow applications is the creation of as little liquid droplets as possible. For example, it is important to use combustion to burn liquid fuels in combustion chambers, fuel-air mixing and complete evaporation of fuel. Liquid fuel should be converted into small droplets and then mixed with air quickly and evaporated. This challenge has been investigated using injectors of various designs and is still being investigated. One of the injectors used is injectors where both gas and liquid are injected into the injector and supplemented with each other. These injectors are referred to as focal injectors, in which gas flows through a typical orifice to...
Simulation of Microcapsule Formation for Cell Encapsulation Application
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Kazemzadeh Hanani, Siamak (Co-Advisor)
Abstract
Co-culture of different cells is necessary for cancer spheroid formation in preclinical drug tests. It is possible to produce thousands of micro-droplets containing different cells, i.e. microcapsules, in a short time, using droplet microfluidics. However the homogeneity of the cell numbers in the droplets has remained as an unsolved problem.Despite the large amount of experimental efforts to reduce the number of undesirable microcapsules, no one tried to utilize the ease of computer aided simulation for investigating different parameters. In this study, we develop a novel method for capturing cell encapsulation using CFD simulations. The effect of the cell suspension inhomogeneity and...
Simulation of Rapid Formation of Multicellular Spheroids in Double-emulsion Droplets with Controllable Microenvironment
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Sadrhosseini, Hani (Supervisor)
Abstract
This study is aimed at simulation of double emulsion formation in a microfluidic double flow focusing device which consists of two cross-junctions connected serially. The water in oil (w/o) emulsions are produced in the first junction. In the second junction, water in oil emulsions are encapsulated by an outer aqueous phase to generate water in oil in water (w/o/w) double emulsions. Water in oil emulsions are formed in hydrophobic channels and water in oil in water double emulsions are formed in hydrophilic channels. A three phase numerical model, based on the VOF-CSF method, is developed for simulating the process of double emulsion formation. An adaptive mesh refinement technique is...
Simulation of Ultrasound Waves Propagation in Soft Tissue in Cancer Treating by HIFU
, M.Sc. Thesis Sharif University of Technology ; Ahmadiyan, Mohammad Taghi (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor)
Abstract
Nowadays cancer has become one of the main and prevailing worldwide challenges in medical field, and many attempts have been made for treatment of this disease. The common methods for cancer treatment, have had significant side effects and even resulted death. The method of “High Intensity Focused Ultrasound” (HIFU) as a non-invasive method, has been welcomed by engineers and doctors and is using in some tumor based cancers. For predicting the level of temperature increasing in tissue, it’s necessary to model the ultrasound waves propagates from HIFU source precisely. The main object of this thesis is modeling and simulation of the behavior of ultrasound wave propagation and investigating...
Self-Focusing of Laser Beam in Relativistic Quantum Plasma
, M.Sc. Thesis Sharif University of Technology ; Sadighi Bonabi, Rasoul (Supervisor)
Abstract
The phenomenon of relativistic self-focusing in nuclear fusion and laser-plasma interactions is very important. Under the influence of this phenomenon, the laser beam can move in plasma a few Rayleigh lengths and the interaction efficiency is improved. The relativistic self-focusing in inhomogeneous, homogeneous, collisional and collisionless plasmas has been studied in various conditions of plasma and laser in classical physics. In this thesis the propagation of a laser pulse at the X-ray wavelength range and its relativistic self-focusing in quantum plasma is investigated by numerical simulations. Initially, the interaction with a collisionless ramped density profile plasma target is...
CTC Cluster Separation on Microfluidics Chip
, M.Sc. Thesis Sharif University of Technology ; Firouzabadi, Bahar (Supervisor) ; Saidi, Mohammad Said (Supervisor)
Abstract
According to statistics in 2012, around 14 million people worldwide have cancer, and 8 million have died that year, according to estimates, this number will increase to 21 millions new cancer case and 13 million mortality in 2030. Despite years of research on cancer, many questions about the mechanism of the spread of cancer in the body remain unanswered so far. The proposed models identify that the cells isolated from the primary tumor and transmit them to the circulatory system in the form of circulating tumor cells (CTCs) or in the form of clusters as responsible for the incidence of cancer. This process is called metastasis. Recent studies have reported the high potential of metastasis...
Production of drug Loaded Microgels Using Microfluidic
, M.Sc. Thesis Sharif University of Technology ; Saadatmand, Maryam (Supervisor) ; Eskandari, Mahnaz (Supervisor)
Abstract
Microfluidic systems have the ability to produce microgels with uniform size distribution and spherical shape due to the laminar flow and better control of the flow rates. Spherical microgels with same size can be used as high-potential carriers for drug release. An important challenge in the production of these drug-carrying microgels is the simultaneous process of drug loading into microgels and their production. The overall goal of this project was to produce drug-carrying microgels with uniform size distribution that show controlled drug release. To achieve this goal, various factors such as the type of polymer, the type of drug, the volume ratio of the polymer and the drug and the...
Production of Liquid Metal Micro-droplets and Electrical Control of their Size and Rate of Formation
, M.Sc. Thesis Sharif University of Technology ; Kebriaee, Azadeh (Supervisor)
Abstract
The use of liquid metal droplets due to their high electrical and thermal conductivity are used in various industries today. One of the methods of producing these micro-droplets is the flow focusing method, which is widely used to produce integrated and monodispersed droplets. Liquid metals have high surface tension and these micro-droplets are formed only if there is sufficient shear force between the liquid metal and a continuous fluid phase. In the past, they used several different methods such as pressure fluctuations and changes in continuous phase flow rate to control the shear force and produced polymer, gas, etc. micro-droplets.In this research, use the electric potential to control...
Production of Electron and Flat Ion Blocks by Using Ultra Intense Laser, Particularly in the Ultraviolet Range
, Ph.D. Dissertation Sharif University of Technology ; Anvari, Abbas (Supervisor) ; Sadighi Bonabi, Rasoul (Supervisor)
Abstract
In the present work, interaction of high power and ultra short laser pulse with plasma in both under relativistic and relativistic regimes is investigated. The accelerated ions and electron are studied. The effect of pulse laser shapes on generating of the optimum wakefield is studied to find the maximum generated wakefield amplitude. It is found that similar to the wakefield amplitude generated by single pulse, the wakefield amplitude produced by dual trailing depends on the pulse shape and their permutation. Furthermore, the interaction of sub-picosecond UV laser in sub-relativistic intensities with deuterium is investigated. At high plasma temperatures, based on the quantum correction in...
Focusing Wave Beyond the Diffraction Limitin Hyperthermia Application
, M.Sc. Thesis Sharif University of Technology ; Shishegar, Amir Ahmad (Supervisor)
Abstract
In this research, diffraction limit is introduced as the major challenge in wave focusing. Common wave focusing techniques have been reviewed and classified into two categories: far-field and near-field techniques. Through examples that illustrate its major inherent and practical challenges, super-oscillation has been presented as a specific idea of focusing waves using remote sources. By introducing subwavelength inhomogeneities in the region of interest, we have demonstrated sub-diffraction wave focusing in a near-field approach. Using the multipole method, the effect of injecting sub-wavelength cylindrical particles on focusing electromagnetic waves has been studied. Since when there are...
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...