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... 

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... 

Continous blood glucose control has great importance for type 1 dyabetic patients. In this thesis, several types of controllers including: PI controller, model predictive controller base on state space model, linear model predictive controller base of linear input-output model and non-linear model predictive controller base of Hammerstein model have been used to regulate blood glucose of patients with type 1 diabetes. These models are identified using least squars method. Performance of these controllers is tested and the best one is introduced. For rejecting meal disturbances, a feedforward controller has been designed. Combination of feedback and feedforward controller would properly... 

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... 

In this project Deployment of multi-agent systems was studied. Maximum coverage over a point or curve or area is desired in deployment of multi-agent systems. A facility location optimization function was derived from geometrical concepts such as voronoi, n- geometric median and fermat-weber problem by optimization of which the deployment of multi-agent systems is performed. First, it is assumed that dynamic of agents is first order and second order .Next, it is assumed that agents are in a fluid. In all situations a suitable control algorithm was derived to optimize the facility location function to perform deployment. Next, another facility location function was derived by optimization... 

This study proposes a deep reinforcement learning approach to solve a perishable inventory allocation problem in a two-echelon supply chain. The inventory allocation problem is studied considering the stochastic nature of demand and supply. The examined supply chain includes two retailers and one distribution center (DC) under a vendor-managed inventory (VMI) system. This research aims to minimize the wastages and shortages occurring at the retailer's sites in the examined supply chain. With regard to continuous action space in the considered inventory allocation problem, the Advantage Actor-Critic algorithm is implemented to solve the problem. Numerical experiments are implemented on... 

Hypertension precvalence is 24 and 20.5 percent in men and women, respectively. Continuous Blood Pressure monitoring can provide invaluable information about individuals’ health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This work presents an efficient algorithm, based on the Pulse Arrival Time (PAT), extracted from Electrocardiogram (ECG) and Photopletysmograph (PPG), for the continuous and cuff-less estimation of the Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Mean Arterial Pressure (MAP) values. Methods: The proposed framework estimates the BP values through processing vital... 

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... 

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... 

Red Blood Cells (RBCs) are the main cells in human blood with a main role in mechanical properties of blood as a fluid. Several methods are developed to simulate the behavior of RBCs motion and deformation in micro-capillaries. Since in microscopic scales, using discrete models are more preferred than continuum methods, moving particle semi-implicit method (MPS) which is one of the recent innovative particle based methods, can simulate micro-fluidic flows based on Navier-Stocks equations. Although by the recent developments MPS method has turned into a considerable tool for modeling blood flow in micro-scales, but still some problems, such as commitment to use small time steps, restrict the... 

Nowadays, all of the devices that measure blood pressure commercially at home are using wrist or arm cuffs preventing the systolic or diastolic blood pressure from being measured continuously. Various parameters such as blood flow with some degree of correlation with blood pressure that can be measured noninvasively have been suggested. However, these parameters do not produce accurate estimates for blood pressure. Pulse Transit Time (PTT) which is defined as the interval between the R peak of ECG signal and the next PPG signal valley has shown to have over 90% correlation with systolic blood pressure in past studies. In this thesis, the relationship between the value of the systolic blood... 

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... 

As the number of patients waiting for receiving kidney transplantation increases all over the world, the average waiting time for a patient in queue rises too, and consequently, the rate of death goes beyond the accepted level. Also, unbalanced numbers of donors and patients with same blood type make the problem bolder. The aim of this research is to design a queuing model in which kidney could be transplanted from deceased donors to patients with different but compatible blood type (Cross-Transplantation) in order to make the average waiting time for patients with different blood type closer to each other. In other words, the transplant system is supposed to make a decision whether to... 

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... 

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... 

Ultrasound hyperthermia is a commonly used noninvasive approach to destroy cancer tumors. High Intensity Focused Ultrasound (HIFU) is a technique based on hyperthermia. It creates short and local elevations of temperature at a focus site within the tissue of interest. The main goal of HIFU is to maintain the temperature between 50 and 100 °C for a few seconds (typically less than 10 s), in order to cause tissue necrosis. In order to predict the effects of hyperthermia, accurate and effective modeling is needed. This study considers a 3D simulation of the hyperthermia based on HIFU method in the liver tissue. Temperature distribution and lesion volume changes, with a temperature of above... 

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... 

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... 

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.... 

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...