Sharif Digital Repository

Constant drilling in the shale formation causes many problems such as shale swelling and well instability. Annually many costs are spent dealing with these problems in the drilling industry. Many factors can affect this issue. The most important factor is the type of drilling fluid and its additives. The use of oil-based mud is the best option to deal with the clays instability but, due to environmental problems resulting from OBM, their use has been banned in most parts of the world. Therefore, the water-based mud is the only option for the oil industry that can modify its property by use of additives. In this study, the muds contain Nano silica have been introduced. Silicate as shale... 

Problems with the mitral valve can make the heart less efficient at pumping blood around the body. Severe problems can lead to heart failure if the valve is not surgically repaired or replaced. A simple approximation of the heart geometry is used and the valve dimensions are based on reported measurements. The primary objective for this study is to design and simulate the opening and closing behavior of the mitral valve using 2D fluid-structure interaction (FSI) model using ADINA software in order to evaluate and investigate the hemodynamic performance and problems of mitral valve, in which the blood is described as a viscous incompressible fluid, and the mitral valve is described as an... 

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... 

Diabetes is a global problem as a silent epidemic disorder. Diabetes Mellitus has involved at least five percent of our population. It will cause so many complications and end-organs effects if it is not controlled. Today, treatment and control of diseases using computational intelligent systems has been paid a lot of attention to. That’s why this study has taken treatment and control of diabetes into consideration. So, the neural networks have been used to manage and treat diabetes. To do this, real data from diabetic patients has been gathered and based on the data, a model has been obtained to show the effect of insulin on the amount of blood glucose. Then, a neural network controller has... 

One of the diseases of the central nervous system that are included in the neurodegenerative disorders and its impressive expansion among the people of the world and Iran is an alarming to us, is Alzheimer's disease. Since the cause of the disease has not yet been precisely determined, there is no definite cure for this disease yet. However, an important indicator in the disease is its early diagnosis so that the disease can be controlled and prevented from progressing in the early stages and before the degeneration of neurons. The big challenge that is observed in the diagnosis and effectiveness of drugs in this disease and any type of central nervous system disorder is the existence of the... 

Magnetic resonance imaging is one of non-invasive methods to measure the hemodynamic and morphologic parameters of tissues, especially brain tissues. Hemodynamic parameters monitoring in brain tissue is of significant importance in many majors such as detection of tumor occurrence, brain abnormalities, and track of treatment procedures. Blood is a suspension, comprised of plasma, red blood cells, white blood cells, platelet, etc. Plasma is a Newtonian fluid which is composed of proteins and has a constant viscosity in body temperature. Rheological properties of blood are highly dependent on mechanical and rheological properties of its cells and this dependence is multiplied in narrow vessels... 

This study seeks to investigate the factors affecting consumer behavior when using a home blood glucose tester. Most of the previous research has been on improving the performance of home medical equipment to measure vital parameters such as pressure, sugar, oxygen, etc. They have also taken steps to increase the possibility of learning and easy use of the product, which only examines consumer behavior during use .In order to achieve this goal, the theory of planned behavior has been used. In this behavioral theory, the intention to perform a specific behavior, which in this study is the monitoring of blood sugar by the patient, is examined. Behavioral intent is the attitude towards use,... 

Blood clotting and clot formation in damaged vessels are vital mechanisms of the body. Any disorder in performing this mechanism leads to various problems such as excessive bleeding or, on the contrary, causes vascular occlusion and diseases such as embolism. Due to the importance of this issue, extensive research has been done to understand this phenomenon and the factors affecting it. In this thesis, the effect of shear stress, coagulation factor concentration and wound location in coronary bifurcation on clot formation and growth and its interaction with velocity field is numerically investigated. Blood flow is modeled non-Newtonian with Carreau-Yasuda model. Various chemical species... 

Warming the injectable blood is a set of methods used to transfuse blood to the supplier (Accident patients, surgery, dialysis). These methods raise the temperature of the injected blood to body temperature. Blood transfusions are performed directly before World War II, so there is no need to heat the blood, Increased need for blood units caused blood banks. In these banks, to prevent the proliferation of pathogens, the temperature of blood units is reduced to 2-6 degrees Celsius. For indirect injection of these blood units, the injection temperature should be brought to the patient's body temperature before injection to prevent the recipient's body temperature from decreasing.In this... 

Blood glucose regulation in type 1 diabetes patients requires the delivery of the proper amount of insulin from an external source. The literature of Blood Glucose Control signifies the superiority of model-based controllers over the other ones. Regarding its lack of need to complicated on-line calculations and the simplicity of its implementation on a micro-chip, the explicit Model Predictive Controller is preferred over the implicit MPC. Currently proposed explicit MPC controllers have employed relatively simple models representing human glucose-insulin dynamics. In this thesis, an explicit MPC controller is designed using mp-QP based on Sorensen’s 19-state comprehensive model which has... 

Atherosclerosis, due to the penetration of low-density lipoprotein particles (LDL) into the arterial wall, is one of the most common and death-leading diseases in today's world. Due to its importance, extensive research has been conducted on the factors that affect this disease. In this thesis, a numerical study of the effects of Wall Shear Stress (WSS), non-Newtonian behavior of blood, different hematocrit values, and blood pressure on LDL permeation through the artery wall layers are investigated in a 4-layer wall model of a coronary bifurcation. To obtain the velocity and concentration fields in the domain, momentum, Brinkman, and mass transport equations are solved in the lumen and wall... 

Heart is a muscular organ, which pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste to the lungs. Heart is sort of like a pump, or two pumps in one. The right side of heart receives blood from the body and pumps it to the lungs. The left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body. However, in end-stage heart failure, the heart can no longer pump enough blood to meet the body’s needs, in which case implantable left ventricular assist devices provide support for patients at risk of death from end-stage heart failure.Centrimag... 

Patients with a single ventricle disease who have undergone Fontan surgery have always had long-term complications. These complications include pulmonary artery stiffness and decreased ability to exercise. In fact, due to removal of the right ventricle from the circulatory system, blood pressure and pulsatility inflow to total cavopulmonary connection (TCPC) are reduced following this surgery. Creating waves (radial displacement) on the IVC (Inferior Vena Cava) wall can increase pulmonary flow pulsations. The Objective of this study is to test the effect of induced wave amplitude on the pulmonary flow pulsations at the rest condition. Computational fluid dynamic (CFD) simulations were... 

In medical science, preparing a high purity sample of certain kinds of cells plays an important role in studying the characteristics and functionality of cells, detecting in vitro harmful pathogens and helping to find ways of preventing and treating diseases that cause cellular disorders in the human body. The goal of this research is to improve the spiral microchannel with stair-like cross section in order to separate white blood cells from whole blood. First, the efficiency of this method was evaluated numerically, using a developed finite element model. Then, the desired microchannel mold was made using the micromiling method, and we fabricated the chip using soft lithography and pasting... 

The heart is a powerful muscle whose primary function is to pump blood into the body. many cardiac patients reach a stage that can no longer be kept function of their heart to a satisfactory level by using medication thus doctors undergo surgery. The common problem occurs to most patients undergoing cardiac surgery is that after the surgery, the patient's heart during a short period of time is unable to supply blood with the flow rate and pressure required for all organs, especially the end organs of the body. In this conditions, ventricular assist device help the patients. These devices are used parallel with patient’s heart and supply the large portion of blood that patient’s body needs.... 

In this thesis, hemodynamic parameters of flow and deposition of low density lipoproteins (LDL) on wall of coronary arteries with taking into account their curvature on the heart are studied. At first, numerical solution of the blood flow by assumption of blood as incompressible and Newtonian fluid for steady and pulsatile inlet is done. Then by assuming LDL particles as dilute solute in the blood, LDL transport from artery lumen into arterial wall is studied. LDL accumulation and penetration into the vessel wall cause thickening of the walls and eventually eclipse it and its known as the first stage of atherosclerosis disease. The results show that low shear region occurs on inner wall... 

This thesis presents my Ph.D. research study focusing on the dynamic analysis of magnetic nanoparticles (MNPs) for epilepsy and blood-brain barrier (BBB) applications. In this analysis, we took into account various parameters including the magnetic field, fluid behavior, geometry and material of MNPs. Based on this computational study, the generated magnetic field in epileptic foci results in the aggregation of nanoparticles. This may offer the advantage of using MNPs as a Magnetic Resonance Imaging (MRI) contrast agent. Furthermore, in this study, we also demonstrated and discussed the advantage of MNPs for crossing BBB using the external magnetic field. The outcome of this research project... 

Trombosis formation in blood flow is a complex biochemical and very important process for body health which impedes blood loss by creating obstacles in the path of injured wall vessels. Although this phenomenon plays a very significant role in healthy body function, unfortunately it has been observed that it could cause diseases or even stroke. The reason is that thrombosis formation in blood and its detachment from the vessel wall can result in block body capillaries and lead a catastrophic event for the body. One of the factors which motivates blood for forming unnatural thrombosis is the vessel stenosis. It would ange in normal blood flow path and cause thrombosis formation as time is... 

Single ventricle anomaly is a congenital heart disease which is characterized by anatomical malformations. The main abnormality that a patient faces is desaturated blood flow, which, without any treatment increases the risk of death. The classical treatment is based on a three stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure which directly connects inferior vena-cava to pulmonary arteries without going through the ventricle.This connection is known as Total Cavo Pulmonary Connection (TCPC). After surgery, the single ventricle could supply adequate and saturated systemic blood flow for the body, but TCPC... 

The mathematical analysis of the kidney has always been considered due to its complex performance. It’s about two decades that mathematicians work on the mathematical modeling of this tissue. Since Glomerular filtration of blood in the kidney has been regarded by physiologists for many years, they can access only to the qualitative data. Mathematicians can solve this problem by numerical modeling. In this research, an engineering model is presented for the analysis of this capillary network by investigating in the different scientific fields such as, physiology, medicine, computer science and mathematics.First of all, the homogeneous model introduced by Deen, are studied. The rate of the...