Search for: microfluidics
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    Mass Transport Analysis of Non-Newtonian Fluids under Combined Electroosmotically and Pressure Driven Flow in Rectangular Microreactors

    , M.Sc. Thesis Sharif University of Technology Yousefian, Zakie (Author) ; Saidi, Mohammad Hassan (Supervisor)
    In recent two decades, with developments in micro and nano scale fabricating techniques, use of microfluidic systems is increasing in different fields. How to drive fluid is a hard question because of high pressure drop in micro scale. Different methods has been suggested to solve this problem, among which, electroosmotic pump is preferred because of its advantages. One of the main applications of microsystems is in biomechanical devices like microreactors which are usually working with non-Newtonian fluids. The cross section of these devices are most often close to rectangular shape.Therefor, in this study,Hydrodynamic charactristics and mass transport of non-Newtonian fluids under... 

    Monitoring of Biodegradation of Oxalate in Microfluidic Bioelectrochemical Systems

    , M.Sc. Thesis Sharif University of Technology Yousefi, Reyhaneh (Author) ; Bastani, Daryoush (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Mardanpour, Mohammad Mehdi (Co-Supervisor)
    In present study, bioelectrochemical degradation of oxalate as a substance which its concentration in kidney leads to urolithiasis in a microfluidic microbial fuel cell (MFC) was investigated. In addition, to define a novel application for the microfluidic MFC, measurement and monitoring of oxalate concentration were studied. This application can introduce the system as an implantable medical device for medical usage of urolithiasis and hyperoxaluria diseases. In this work, by designing and fabrication of two MFCs including a large-scale and microfluidic one, and measuring the outlet concentration of oxalate in the large-scale system, the outlet concentration of oxalate at microfluidic MFC... 

    Simulation of Fluid Aliquoting in Centrifugal Microfluidics

    , M.Sc. Thesis Sharif University of Technology Yousefpour, Mohammad Hossein (Author) ; Moosavi, Ali (Supervisor) ; Arghavani, Jamal (Supervisor)
    In this thesis, a numerical analysis of micro chamber filling in centrifugal microfluidics is investigated. In the development of micro total analysis systems, it is often necessary to achieve complete and uniform filling of relatively large micro chambers. With centrifugal devices, these large micro chambers must often be orientated perpendicularly to the direction of centrifugal force and are usually bounded by materials with varying surface properties. On the other hand, the mixing characterization of two fluid by centrifugal microfluidic method has been also conducted. The multiphase flow analyses based on Eulerian-Eulerian approach have been conducted and the VOF method was used for ... 

    Simulation of Microcapsule Formation for Cell Encapsulation Application

    , M.Sc. Thesis Sharif University of Technology Yaghoobi, Mohammad (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Kazemzadeh Hanani, Siamak (Co-Advisor)
    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... 

    The Fabrication of the Coupled Microfluidic Microbial Electrochemical Cells for Oxalate Biodegradation

    , M.Sc. Thesis Sharif University of Technology Yahyanezhad Gele, Maedeh (Author) ; Yaghmaei, Soheila (Supervisor) ; Mardanpour, Mohammad Mahdi (Co-Supervisor)
    This study invewstigates the performance of a coupled microfluidic microbial fuel cell-microbial electrolysis cell producing biohydrogen in presence of shewanella oneidensis MR-1 from excreted oxalate of human metabolic processes. The effect of different parameters such as cell geometry including spiral and straight microchannels, precipitation of nano-particles on anode surface, substrate flowrate and the number of microfluidic microbial fuel cell supporting required power for microbial electrolysis cell were assessed. By anode modification, the maximum current density of 428 W m-3 was obtained which is less than 6-fold of the maximum power density in the cell fabricated by zinc foil. The... 

    Design and Fabrication of a Microfluidic Kidney Nephron-on-Chip Platform

    , M.Sc. Thesis Sharif University of Technology Yahyazadeh Shourabi, Arash (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Hajilouy Benisi, Ali (Supervisor) ; Moghadas, Hajar (Co-Supervisor)
    In this manuscript, we designed and fabricated a novel integrated microfluidic Kidney Nephron-On-Chip. This chip is able to culture cell monolayers under various fluid shear stresses and divert osmotic pressure gradients while imposing four different concentrations of an injected drug on cells. The multi-layer platform consisting of two bubble-trappers to eliminate all unwanted bubbles from the system, a concentration gradient generator to generate four different concentrations of the injected drug, and a membrane-based cell culture chamber caple of providing renal cells with their in-vivo condition. Using colorimetric techniques, the bubble trapper ability was quantified at flow rates up to... 

    Design and Simulation of a Microfluidic Blood Cells Counting Device

    , M.Sc. Thesis Sharif University of Technology Yavari, Meysam (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Sani, Mehdi (Supervisor)
    A Lab-On-a-Chip (LOC) is a device which can integrate one or many laboratory functions on a small chip with millimeters to few square centimeters in size. LOC is a subset of MEMS devices and known as “Micro Total Analysis Systems” (µTAS) as well. LOC technology is closely related to microfluidics which primarily describes the physics, manipulation and study of minute amount of fluids.In this research we tried to simulate the performance of a microfluidic device for counting blood cells to find main factors of it for design and manufacturing. This research has two main sections, hydrodynamics of fluid inside the microchannels and finding electrical performance of designed Coulter counter for... 

    Investigation and Characterization of Circulating tumor Cells (CTCs) by the Microfluidics Systems

    , M.Sc. Thesis Sharif University of Technology Yari, Alireza (Author) ; Vossoughi, Manoucher (Supervisor) ; Alemzadeh, Iran (Supervisor) ; Shamloo, Amir (Supervisor)
    Cancer is the second leading cause of death among humans as one of the major human concerns. More than 500,000 people die of cancer each year in the United States alone. Cancer mortality is mainly due to cancer metastasis. Metastasis is the escape of cancer cells from a primary tumor, the circulation of cells in the circulatory system (CTSs), the penetration of/from vessel wall, and the formation of a secondary tumor. It is still not clear how the cells survive in the circulatory system, along with the mechanical pressures and stresses that exist in the body's capillary channals. In this study, a microcirculation model for circulating cells with barriers was designed and constructed by the... 

    Simulation, Design and fabrication of Kidney on a Chip

    , Ph.D. Dissertation Sharif University of Technology Kiyoumarsioskouei, Amir (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Supervisor) ; Mosadegh, Bobak ($item.subfieldsMap.e)
    Renal diseases and consequently kidney failure is one of the important death factors around the world in recent years. It causes hundreds of thousands die every year and is in progress. Researchers believe that increasing chemical and nonchemical materials density in the blood which is the air pollution, use of tobacco and other parameters cause renal cells misfunction in urine filtration and regulation of blood pressure. The goal of this work is design and fabrication of a microfluidic device which provides different cell types to be cultured and imposed pressure. To do this, a high throughput microfluidic device is needed to mimic kidney biologically. Having such a device helps to analyze... 

    Micromodel Investigation of the Non-Monotonic Effect of Injection Water Salinity on Wettability and Oil Recovery

    , M.Sc. Thesis Sharif University of Technology Karimpour Khamaneh, Mehran (Author) ; Mahani, Hassan (Supervisor)
    Based on numerous laboratory and field evidence, low-salinity waterflooding or engineered salinity waterflooding can lead to enhanced oil production. According to the literature, the mechanisms involved in this process can be divided into two general categories: fluid-fluid interactions and solid-liquid interactions. These mechanisms are caused by intermolecular and electrostatic forces at the rock and fluid interfaces. The most important controlling factor of the electrostatic forces is the concentration of ions at/near fluids-rock interface. Therefore, improving the concentration of ions causes a shift in wettability toward a more water-wetting state, eventually leading to increased oil... 

    Simulating Dynamics of Immiscible Liquids Separation Using Microfluidics

    , M.Sc. Thesis Sharif University of Technology Kamrani, Soroush (Author) ; Mohammadi, Aliasghar (Supervisor)
    Most of industrial and laboratory processes are faced with liquid-liquid emulsions particularly aqueous-organic ones in their different product streams which determine the need to perform phase separation due to enviromental problems or need to increase the product purity. In this project, due to presence of a water-hexane two phase flow mixture in the outflow of a microractor that performs Lithium-Bromine exchange reaction, a capillary microchip separator has been designed in order to separate water through capillary channel and hexane through main channel outlet using interfacial forces and wettability effects. To obtain a desired phase separation, the pressure drop through main channel... 

    Bromo-lithium Exchange Reaction in Organic Synthesis and Continuous Separation of Organic and Aqueous phase Reactions by Microfloid Technique

    , M.Sc. Thesis Sharif University of Technology Pourasghar Mohammadi, Ali (Author) ; Mohammadi, Ali Asghar (Supervisor) ; Bastani, Dariush (Supervisor)
    Today, with the development of micro-technology in chemical reactions, the use of appropriate systems for the separation and purification of synthesized chemicals seems to be necessary. In this study, the continuous synthesis of bromide-lithium exchange reaction and the separation of organic and aqueous phase products in micro systems was investigated.The method used to construct micro-separator and micro reactor, a laser engraving technique, and thermal bonding of glass to glass.In the first step, the factors affecting the separation of organic and aqueous phase in the capillary micro-separator, such as the width of the capillary, the length of the capillary, the number of capillaries and... 

    Combined Electroosmotically and Pressure Driven Flow of Power-Law Fluids in Rectangular Microchannels

    , M.Sc. Thesis Sharif University of Technology Vakili, Mohammad Ali (Author) ; Saidi, Mohammad Hassan (Supervisor) ; Mozafari, Ali Asghar (Supervisor)
    Electroosmosis is the predominant mechanism for flow generation in lab-on-a-chip devices. These microfluidic devices are microscale laboratories on a microchip that can perform clinical diagnoses. Since most biofluids encountered in these devices are considered to be non-Newtonian and the cross section of microchannels in these devices is close to a rectangular shape, In this study, the hydrodynamically and thermally fully developed combined electroosmotically and pressure driven flow of power-law fluids in rectangular microchannels is analyzed. The governing equations are first made dimensionless and then transformed into new ones based on the computational parameters which provide mesh... 

    Design and Simulation of a Passive Microfluidic Device for Particle Separation

    , M.Sc. Thesis Sharif University of Technology Vatankhah, Parham (Author) ; Shamloo, Amir (Supervisor)
    Nowadays, separation and filtration of particles has many industrial applications in biology and medicine. In this thesis, passive microfluidics are designed and simulated which are able to separate and filter particles. Although particles aer generally expected to follow laminar flow streamlines in the absence of external forces, inertial forxes van cause particles to migrate across mictochannels in an accurate and predictable manner. The effect of these forces is invedtigated, and by using previous research, a model is developed to predict these forces. First design is a microchannel with Archimedean spiral which utilizes both inertial forces and Dean flow to separate particles in the... 

    CFD-Assisted Design of Microreactor and Evaluation for Continuous Drug Synthesis

    , M.Sc. Thesis Sharif University of Technology Varposhti, Daniel (Author) ; Kazemeini, Mohammad (Supervisor) ; Hosseinpour, Vahid (Co-Supervisor)
    Manufacturing in many industries, such as electronics, petrochemical, automotive, and food, has long relied on continuous approaches, while the pharmaceutical industry has traditionally been processed in batch reactors. Since the beginning of the third millennium, continuous drug synthesis has received attention due to its multiple advantages over batch systems, which include process safety, adaptability, controllability, economic efficiency, scale-up, and enhancing performance. In this project, the pharmaceutical intermediate 1,4-benzodiazepine, which is usable as a precursor of diazepam and flurazepam, is continuously synthesized in a 400 microliters integrated micromixer and microreactor... 

    Implementation of Paper Sheets into the Microfluidic Systems as an Appropriate Platform for Micro-Solid Phase Extraction

    , M.Sc. Thesis Sharif University of Technology Hashemi Hedeshi, Mahin (Author) ; Bagheri, Habib (Supervisor)
    In this research, the surface of cellulose paper was modified with Hexadecyltrimethoxysilane, Phenyltriethoxysilane, (3-Aminopropyl)triethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane via chemical bonding. Afterwards, the prepared papers were placed in the microfluidic device as sorbent in a sandwiched format. A syringe pump was used to drive the sample into the microfluidic channel. In order to investigated the performance of these sorbents, two types of anlaytes including toxins and antidepressant drugs were chosen as target analytes. In the case of toxins, ethion, fenthion, profenfose, diazinon, atrazine and ametryn were studied. among the antidepressant drugs,... 

    3d Design of a Microfluidic Chip for Anticancer Drugs Screening

    , M.Sc. Thesis Sharif University of Technology Hashemi, Maryam Sadat (Author) ; Mashayekhan, Shohreh (Supervisor) ; Saadatmand, Maryam (Supervisor)
    Nowadays, advanced and inexpensive pre-clinical methods for investigating the effects of anti-cancer drugs are expanding. One of the latest three-dimensional laboratory modeling for evaluating the effects of drugs is the use of tumor-on-chip technology, which actually models the physiological system of the body through three-dimensional scaffolds, multicellular cultures, and shaped vascular systems. In this study, three-dimensional culture of cancer cells was performed in the form of spheroids. A chip of U-shaped microstructures with and without gaps was used to trap cells and form cancer spheroids. We simulated the simultaneous effect of drug and oxygen concentration distribution inside the... 

    Design and Numerical Simulation of a Micro-chip for Separating CTCs from Peripheral Blood

    , M.Sc. Thesis Sharif University of Technology Niknam, Hamid Reza (Author) ; Saeedi, Mohammad Saeed (Supervisor)
    According to studies, cancer is the second leading cause of death in the world and millions of people die from this disease every year. Early diagnosis is one of the most important factors in controlling and treating the disease. The ability of circulating tumor cells to diagnose and monitor the disease has led many researchers to focus on studying and researching these cells in recent years. However, due to the fact that the concentration of this type of cells in the blood is very low, their isolation is associated with challenges. Various methods isolate CTCs based on physical, biological and other differences in characteristics. In this study, we investigate performance of a microfluidic... 

    Numerical Simulation of Glucose Metabolism and Hepatocyte Viability within a Microfluidic

    , M.Sc. Thesis Sharif University of Technology Nejadnasrollah, Farzam (Author) ; Firoozabadi, Bahar (Supervisor)
    The advent of microfluidics as suitable environments for culturing cells is associated with some challenges such as shear stresses applied on the cells. In fact, hepatocytes lose their function as exposed to high shear stresses similar to other cell types. Moreover, among all factors needed for cell viability, feeding hepatocytes with adequate oxygen is of great importance due to their high demand for oxygen compared the other cells. In this thesis, different types of cultures including 2D and 3D has been used in order that shear stresses would be in allowed range and provision of hepatocytes with sufficient oxygen concentrations has been ensured as well. In addition to supplying hepatocytes... 

    Design and Simulation of a Spiral Based Microfluidic Device for Separation of Circulating Tumor Cells Using Tunable Nature of Viscoelastic Fluid

    , M.Sc. Thesis Sharif University of Technology Nouri, Mohammad Moein (Author) ; Saeedi, Mohammad Saeed (Supervisor)
    Nowadays, cancer, which has been mentioned as the disease of the century, is the second leading cause of death throughout the world, and its incidence is constantly increasing. Isolation of circulating tumor cells is one of the most critical steps in diagnosing and controlling cancer progression. Due to the rarity of cancer cells compared to other cells in the blood sample, the isolation process requires optimal and high-precision devices. With the advent of inertial microfluidics, the ability to control the particles movement, the processing of blood samples as quickly and accurately as possible, and the viability of cells with a high percentage, introduced microfluidic systems as a...