Search for: particles-separation
Article Microfluidics and Nanofluidics ; Volume 21, Issue 7 , 2017 ; 16134982 (ISSN) ; Kowsari Esfahan, R ; Saidi, M. S ; Firoozbakhsh, K ; Sharif University of Technology
Springer Verlag 2017
Particle separation has a variety of applications in biology, chemistry and industry. Among them, circulating tumor cells (CTCs) separation has drawn significant attention to itself due to its high impact on both cancer diagnosis and therapeutics. In recent years, there has been growing interest in using inertial microfluidics to separate micro/nano particles based on their sizes. This technique offers label-free, high-throughput and efficient separation and can be easily fabricated. However, further improvements are needed for potential clinical applications. In this study, a novel inertial separation technique using spiral microchannel having stair-like cross section is introduced. The...
Continuous size-based focusing and bifurcating microparticle streams using a negative dielectrophoretic system, Article Microfluidics and Nanofluidics ; Volume 14, Issue 1-2 , 2013 , Pages 265-276 ; 16134982 (ISSN) ; Saidi, M. S ; Sadeghi, A ; Sani, M
Dielectrophoresis (DEP) is an electrokinetic phenomenon which is used for manipulating micro- and nanoparticles in micron-sized devices with high sensitivity. In recent years, electrode-based DEP by patterning narrow oblique electrodes in microchannels has been used for particle manipulation. In this theoretic study, a microchannel with triangular electrodes is presented and a detailed comparison with oblique electrodes is made. For each shape, the behavior of particles is compared for three different configurations of applied voltages. Electric field, resultant DEP force, and particle trajectories for configurations are computed by means of Rayan native code. The separation efficiency of...
M.Sc. Thesis Sharif University of Technology ; Shamloo, Amir
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...
M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar
Separation of particles and cells is one of the most important and practical methods in fields such as biomedicine, medicine and industry. In microfluidics There are various methods for particles and cells separation According to the source of them, they can be categorised as active and passive techniques. Active techniques rely on an external force field. The most important advantage of this method is controlling the force on the particles during the experiment. However, the flow speed is always limited because particles must be exposed to the outer force field for sufficient duration to achieve effective functionality. passive techniques depend entirely on the channel geometry or intrinsic...
Article Soft Matter ; Volume 7, Issue 3 , Nov , 2011 , Pages 1107-1113 ; 1744683X (ISSN) ; Babadi, M ; Fukuda, J. I ; Ejtehadi, M. R ; Sharif University of Technology
The interaction between two spherical colloidal particles with degenerate planar anchoring in a nematic media is studied by numerically minimizing the bulk Landau-de Gennes and surface energy using a finite element method. We find that the energy achieves its global minimum when the particles are in close contact and forming an angle = 28°± 2 with respect to the bulk nematic director, in agreement with the experiments. Although the quadrupolar structure of the director field is preserved in the majority of configurations, we show that for smaller orientation angles and at smaller inter-particle separations, the axial symmetry of the topological defect-pairs is continuously broken, resulting...
Simulation and Optimization of Relatively New Catalyst Recovery from Old Catalysts Used in the FCC Process by Applying Electrostatic Field, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davood ; Fotovat, Farzam
In this thesis, the separation process for used and relatively new catalysts of residue fluid catalytic cracking unit by applying an electric field was evaluated. The main purpose of this dissertation is to simulate and design a separation system for separating used and relatively new catalysts of the FCC process in the electrostatic fields. In this regard, various separators were studied, and most of them were simulated under different circumstances. Finally, after examining and analyzing the particle behavior in each of the scenarios, the proposed system was introduced as more effective and efficient than the other separators in order to achieve the ideal separation of the used and...
Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Hassan ; Saeedi, Mohammad Saeed ; Shafii, Mohammad Behshad
Contactless and nonintrusive methods in particulate manipulation have been considered by many investigations. Particularly the use of these methods in characterization of micro and nano flows is in the focus of interests. Laser usage in the particulate systems has been dramatically increased during the last two decades. Laser can be used either as an illustration or excitation source in these systems. So-called optical tweezers use the laser beam for particle manipulation and characterization based on the hydrodynamic interaction of the laser beam with particles. There are numerous works being conducted in the field of particulate manipulation and characterization using laser beam.Present...
Simulation of Cell and Particle Separation by Combination of Dielectrophoretic and Inertial Forces in a Microfluidic Device, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Ali Asghar
In this study, the dynamics of microparticles in a straight microchannel in the presence of an inhomogeneous oscillating electric field have been simulated by the immersed boundary method in combination with the lattice Boltzmann Navier-Stokes solver and the lattice Boltzmann method for solving the Poisson equation. The effect of the electric field on the location and number of particle equilibrium positions have been examined. In the absence of the electric field, circular particles will migrate to two stable equilibrium positions. The site of these equilibrium positions depends on the particle size and the fluid flow rate and is independent of the particle density. In the case of negative...
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 ; Saeedi, Mohammad Saeed
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...
Exploring contraction–expansion inertial microfluidic-based particle separation devices integrated with curved channels, Article AIChE Journal ; Volume 65, Issue 11 , 2019 ; 00011541 (ISSN) ; Abdorahimzadeh, S ; Nasiri, R ; Sharif University of Technology
John Wiley and Sons Inc 2019
Separation of particles or cells has various applications in biotechnology, pharmaceutical and chemical industry. Inertial cell separation, in particular, has been gaining a great attention in the recent years since it has exhibited a label-free, high-throughput and efficient performance. In this work, first, an inertial contraction–expansion array microchannel device, capable of passively separating two particles with diameters of 4 and 10 μm, was numerically studied. Then, the validated model was combined with curved geometries in order to investigate the effect of curve features on the separation process. The overall purpose was to investigate the interaction between the two different...
Improvement of size-based particle separation throughput in slanted spiral microchannel by modifying outlet geometry, Article Electrophoresis ; Volume 41, Issue 5-6 , February , 2020 , Pages 353-359 ; Maleki Jirsaraei, N ; Rouhani, S ; Safi, S ; Alizadeh, M ; Sharif University of Technology
Wiley-VCH Verlag 2020
The inertial microfluidic technique, as a powerful new tool for accurate cell/particle separation based on the hydrodynamic phenomenon, has drawn considerable interest in recent years. Despite numerous microfluidic techniques of particle separation, there are few articles in the literature on separation techniques addressing external outlet geometry to increase the throughput efficiency and purity. In this work, we report on a spiral inertial microfluidic device with high efficiency (>98%). Herein, we demonstrate how changing the outlet geometry can improve the particle separation throughput. We present a complete separation of 4 and 6 μm from 10 μm particles potentially applicable to...
M.Sc. Thesis Sharif University of Technology ; Saidi, Mohmmad Said ; Firoozbakhsh, Keykhosrow
Particle separation has a variety of applications in biology, chemistry and industry. Among them, circulating tumor cells (CTCs) separation has drawn significant attention to itself due to its high impact on both cancer diagnosis and therapeutics. In recent years, there has been growing interest in using inertial microfluidics to separate micro/nano particles based on their sizes. This technique offers label-free, high throughput, and efficient separation and can be easily fabricated. However, further improvements are needed for potential clinical applications. In this study, a novel inertial separation technique using spiral microchannel with stair-like cross section is introduced. The...
Numerical Simulation of Particle Classification in Two-Phase Flow in a Vortex-Based Air Classifier Using the Eulerian-Lagrangian Approach and Determining Its Optimized Performance Condition, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud
Using a Numerical simulation approach for modeling multiphase flows is a cost-effective and prevalent method in analyzing the physics of multiphase problems. One of the most applied needs of industry in using gas-particle simulation is the separation of particles using Air Classifiers which are industrial devices that can classify solid inlet particles based on their size using airflow patterns and other mechanisms. The present study focuses on a particular type of classifier using vortex to classify particles. Performance of these classifiers simulated using numerical Eulerian-Lagrangian DDPM model. The two critical studied performance parameters of the classifier are pressure drop and...
Effect of Initial Static Shear Stress on Liquefaction Resistance of Gravelly Soils Using Medium-Size Cyclic Triaxial and Simple Shear Tests, Ph.D. Dissertation Sharif University of Technology ; Haeri, Mohsen
There are several case history records of liquefaction in gravelly layers with more broadly-graded particles than uniform sands which have been typically examined. Liquified deposits, in many cases, were subjected to initial static shear stress associated with the sloping ground condition or the adjacent shallow foundations prior to liquefaction. There are several graphs and recommendations for practitioners to consider the effects of the initial static shear stress on liquefaction resistance in design processes, developed based on the results of experiments on uniform clean sands. However, data for the effect of the initial static shear stress on the liquefaction strength of gravelly soils...
Article IEEE Transactions on Electron Devices ; Volume 66, Issue 3 , 2019 , Pages 1495-1503 ; 00189383 (ISSN) ; Yazdan Parast, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
Nowadays, the importance of the blood particles separation is undeniable in medical fields and there are different sorts of separation methods accordingly. Acoustic cell separation is chosen in this paper. Also, numerical methods have been used to study the effect of geometrical factors on the separation of the particles before spending time and expenses in a trial and error manner experimentally. We have implemented a plenary finite-element-based simulation of separatingblood particles such as white blood cells and platelets in an acoustic field using standing surface acoustic waves. In this paper, unlike previous works in which the channel is rectangular; the channel is trapezoidal in...