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Numerical Multiscale Modelingof Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
Abstract
One of the main reasons of brain attack is stenosis in Carotid bifurcation. As a result, it's a major field of interest for a large group of scientists including medical doctors and engineers. In the engineering fields a large number of studies have been done on this topic based on Numerical Simulation. As blood boundary conditions in this region strictly depend on the rest of the body's vascular system, the problem is the definition of the boundary condition in this approach. In addition, because of lack of enough hardware sources simulation of the whole blood system is impossible; thus the rest of the system should be simulated based on radical methods with less details. In this project a...
Experimental Study on Behavior of Particle-Laden Density Current over Obstacles
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Firoozabadi, Bahar (Co-Advisor)
Abstract
Density currents, caused by the intrusion of dense fluids under lighter ambient fluids, frequently occur in both natural and industrial situations. As a result of the density differences, the driving force can arise from soluble substances, temperature differences, etc. If the driving force comes from suspended particles including silt and mud, the currents are called turbidity currents. Due to the variation in concentration and the consequent driving force along the flow path, turbidity currents are significantly more complicated than saline currents. These currents play the most important role in sedimentation in lakes, seas and oceans. In addition, turbidity currents are the main factor...
Simulation of a Simple Model of Endothelial Cell Using Dissipative Particle Dynamics Method
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Co-Advisor)
Abstract
Endothelium is the interior layer of an artery made up of tremendous number of endothelial cells which are located side by side. Finding the effective parameters that cause the cells to obtain mechanical strength in different morphologies is a major effort in cell engineering studies. In this work a numerical model for endothelial cells is developed. This model has included cell's plasma membrane (the outer membrane of the cell), nucleus and cytoskeleton main components including intermediate and actin filaments as well as microtubules. The model has been validated by simulating the adhesion of the cells to a flat substrate and also atomic force microscopy (AFM) experiments. The two most...
Simulation, Design and fabrication of Kidney on a Chip
, Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Supervisor) ; Mosadegh, Bobak ($item.subfieldsMap.e)
Abstract
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...
Hydrodynamic Modeling of the Tail of a Thunniform Robofish
, M.Sc. Thesis Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor) ; Seif, Mohammad Saeed (Co-Advisor) ; Firoozabadi, Bahar (Co-Advisor)
Abstract
Underwater robots are broadly used in oceanography to explore ocean environments,inside inspection of pipes, and also to provide security at maritime boundaries. To design an underwater autonomous robot, it is compulsive to take advantage of a high efficient propulsion mechanism to lengthen the tour time span. Since fish-like propulsion mechanisms have presented higher efficiency comparing other mechanisms, they have been paid a lot of attention.In the present research, the hydrodynamic of a thunniform fish robot is analyzed under some reasonable simplifications. Based on the results achieved from this study, closed expressions are developed to predict the steady mean velocity and the...
The Study of the Effect of Surfactant on the Liquid Drop Motion In Fluid
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Supervisor)
Abstract
The drop motion in fluid and the mass transfer is one of the most interesting and favorite topics that has attracted the attention of many researchers. Knowing the functions of the factors affecting the deformation and the process of mass transfer and the effects of the addition of the surfactant, improve the efficiency of the related industrial processes.In this regard, the present study examines how the shape and speed of a moving Newtonian drop in a Newtonian fluid, the mass transfer of soluble material from inside the drop to the surrounding fluid and also the study of the effect of surfactant on the dynamics of moving droplet is studied numerically. During the drop movement, the...
Coupling 3D-1D for Blood flow Simulation in Carotid Bifurcation
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
Abstract
Recently, many investigations are done in the field of the modeling of the cardiovascular system. For the purpose of understanding of this system, mainly the location of formation and development of atherosclerosis, these investigations are so vital. The multi-scale modeling is an appropriate method to reduce the cost of calculation and also, this method simplifies the complicated model of cardiovascular system. This research presents a multi-scale 1D-3D modeling of cardiovascular system. In this model, the three dimensional geometry of carotid bifurcation is coupled with a one dimensional full model of cardiovascular system. We used some user defined function in the Fluent software for...
Experimental Investigation of Mass Transfer by Droplet Using Image Processing
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein ($item.subfieldsMap.e)
Abstract
Wide and varied aspects of droplet motion due to its increasing application in various fields has attracted much attention. Analysis of mass transfer from the liquid drop into the other fluid, such as complex and intriguing problems in fluid mechanics, which is very important. Many experimental and numerical studies have been carried out in this case that the evelopment of laboratory equipment and software, are rapidly growing.
In this study, given the importance of this issue, experimental study on mass transfer in fluid systems solution droplet liquid - liquid extraction, have been considered. Different methods have been discussed to date. In the present study, using image processing...
In this study, given the importance of this issue, experimental study on mass transfer in fluid systems solution droplet liquid - liquid extraction, have been considered. Different methods have been discussed to date. In the present study, using image processing...
Multiscale Modeling of Coronary Blood Flow and Effects on Endothelial Cells
, Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Co-Advisor)
Abstract
Atherosclerosis in coronary arteries is one of the most important topics due to its high prevalence and the importance of these arteries for supplying blood to the heart. The morphology of endothelial cells (ECs) is an independent index for determining the atheroprone sites. The ECs show a regular elongated and aligned configuration to the blood flow, at the atheroprotected regions; on the other hand, at the atheroprone regions, the cells have a polygonal, randomly oriented morphology. The thesis intended to propose a method for coronary artery simulation, which is able to determine the atheroprone sites regarding the ECs morphology. In addition, the attempts were made to investigate the...
Numerical Simulation of Discharged Liquid Jet from Desalination Plants and Investigation Mixing Characteristics with Surroundings
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Today, due to the decline of drinkable water, many desalination plants have been established and operated around the world. Disposal of these brines, which have higher density and temperature than receiving water, causes many environmental impacts. Industrial power plants discharge these effluents into the seawater body mostly as submerged jets due to their higher effectiveness. Many experimental researches have been done on the negative and positive buoyant jet that discharged form desalination plants. But a few numerical studies have been done with investigating the full Navior-Stokes equations and they have been flawed in modeling. For example, some of these models have been able to...
Study the Effect of Considering two Layered wall for Carotid Artery Bifurcation on Distribution of Hemodynamic and Non-Hemodynamic Parameters using a Fluid-Structure Interaction Method
, M.Sc. Thesis Sharif University of Technology ; Dehghan Firoozabadi, Bahar (Supervisor) ; Saidi, Mohammad Said (Supervisor)
Abstract
It is known today that arterial diseases are among the leading cause of death in modern societies. More than 50% of deaths in western countries are mainly occurred as results of these diseases, namely atherosclerosis. In order to study risk factors and to understand the full process of how arterial diseases initiate and progress, many research topics have been introduced and studied. Researchers believe that mechanical factors such as Wall Shear Stress (WSS), Pressure distribution, Cyclic strain, Back flow zones and many other factors are responsible for initiation of atherosclerosis. Different patterns of Wall Shear Stress and Strain are seen in arteries. Among other factors outlined in...
Experimental Study of Droplet Formation in Surfactant Solution
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Advisor)
Abstract
Surfactants are materials that reduces surface tension, and this property has provided a wide range of applications for them. Most of the surfactants reduce surface tensions at the interface of two fluids. The pharmaceutical and food industries, detergents, cosmetics, agricultural pesticides, dye production and oil extraction are among these applications.In this study, the formation of droplets in the presence of three types of surfactants SDS, CTAB and Tween 20 has been investigated. To evaluate the droplet behavior in the presence of specific surfactants, various parameters such as formation time of the droplet, the diameter and length of the droplet formed, the diameter and length of the...
Multi-scale Simulation of Tumor Microenvironment
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Mozafari, Ali Asghar (Co-Supervisor)
Abstract
Search for effective methods for treating cancer requires a deep understanding of the tumor microenvironment and its role in cancerous tumor growth and progression. Mathematical modeling methods, which have fewer limitations than experimental methods for examining the microcirculation of cancer in detail, are suggested to answer many questions about the behavior and dynamics of cancerous tumors. In the present study, a multi-scale mathematical model of the three-dimensional tumor microenvironment, including molecular, cellular, and tissue scales, is presented. In this model, important aspects of tumor microenvironmental dynamics including tumor growth, angiogenesis, cancer metabolism, and...
Fluids Flow Simulation in the Cell Influenced the Focal Adhesions
, Ph.D. Dissertation Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; saidi, Mohammad said (Co-Advisor)
Abstract
In the present thesis, intracellular fluid flows have investigated for study cell motions. It is due to firmly relation between the cell motion and these flows. Generally, the cell firstly adheres to a surface, then, moves forward with the effects of the internal fluid flows. In this study, the cell structure is invided to two general parts; the front part of the cell and the cell body. The front part of the cell plays a essential roles in the cell motion, however, the cell body is considered as a extra cargo that is carried by the front of the cell. Therefor, in the present modellings, the front part is only considered. Here, using four different models for the front part of the cell, many...
Numerical Simulation of Glucose Metabolism and Hepatocyte Viability within a Microfluidic
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
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...
Role of Non-Dimensional Numbers in Density Current Stability
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor)
Abstract
Density currents are occurred as a result of the intrusion of a dense fluid into a fluid with a different density. Density differences are typically caused by the difference in temperature, existence of solution or insoluble material and suspended solids. A special kind of density current is called a turbidity current which is a sediment-laden density current. This is a kind of flow which is driven by the force of gravity on suspended sediment particles that causes an excess fractional density with respect to the surrounding ambient fluid. In this work, the 2-D sediment-laden density current on a sloping surface of the channel is investigated through experiments. The channel is 12 m long,...
Development and Assessment of a Numerical Model for Investigation of Regional Dust Distribution
, Ph.D. Dissertation Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Firoozabadi, Bahar (Co-Supervisor)
Abstract
In recent years, dust storms have been recognized as one of the most crucial problems for people worldwide. Provided that the dust masses transport mechanisms are properly known, the main dust sources can be identified, and therefore, appropriate actions can be taken. Therefore, the main goals of the present study are estimating dust concentration, determination of dust distribution with an emphasis on Iran (especially Tehran), and finding the main dust sources which will be followed in five steps. In the first step, by analyzing the measured data during dust observations in Tehran through 2013-2016, several simple and multivariate nonlinear regression models have been established in order...
Three-Dimensional Large Eddy Simulation of Continuous Density Currents
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Afshin, Hossein (Co-Advisor)
Abstract
When a fluid moves inside another fluid while they have unequal density, a phenomena occurs which is called density (or gravity) current. Therefore density difference and gravity are key factors of density current generation. Due to application in engineering and geology, it is essential to investigate and analyze the above mentioned phenomena. Dam reservoirs, sandstorm in deserts, snow slide onset and falling, ash clouds produced during eruption of a volcano, and spreading of density current due to the collapsing of reservoirs are some examples of gravity current. There are lots of methods to simulate the turbulence of density current like DNS or RANS. But DNS has high computational cost...
Numerical and One Dimensional Modeling of Cardiovascular System
,
M.Sc. Thesis
Sharif University of Technology
;
Saeedi, Mohammad Saeed
(Supervisor)
;
Firoozabadi, Bahar
(Supervisor)
Abstract
Cardiovascular diseases are most common causes of deaths in the whole world. Nowadays, engineers and scientists in various fields become intent on finding solutions for prevention and recovery of these diseases. In this way, it is very important to know about the blood flow in arterial systems and its changes in various diseases. Numerical simulation of the blood flow beside of experimental studies could be very useful in this way. One dimensional simulation among various methods of numerical simulation was chosen to simulate a cardiovascular system since it has smaller computational cost and ability to modeling of whole arterial systems. It also is useful in extraction of medical indexes....
Three Dimensional Large Eddy Simimulation of Lock-Exchange Density Currents
, M.Sc. Thesis Sharif University of Technology ; Firoozabadi, Bahar (Supervisor) ; Farshchi, Mohammad (Supervisor)
Abstract
In this thesis, lock-exchange density currents are investigated using the dynamic large eddy simulation (LES) method. These are flows that occur under the influence of gravity and density gradient. In the lock-exchange type currents, a bulk of heavy fluid is released under an ambient lighter fluid. One charachteristic of such flows is the presence of turbulence at different scales across flow and Kelvin-Helmholtz and lobe and cleft instabilities at the interface, which additionally act to complicate the matter. Although lots of efforts have been devoted to simulate density currents, much of the previous simulations have used Reynolds Average Navier-Stockes (RANS) methods. Practically, these...