Sharif Digital Repository

Monitoring has a high level of importance in the predicting and controlling of dam behavior. At all large dams, the dam performance can be analyzed through the installation appropriate devices during dam construction, impounding and operation periods. The main purpose of monitoring and instrumenting is to investigate variations and safety of dam on the basis of long-term data observations. This paper is aimed at evaluating the behavior of earth dams from the aspect of deformation and settlement during dam construction, impounding and operation periods. As a case study, dams of Shahr chay & Zola, IRAN, have been studied. For this purpose, the obtained results from modeling, deformation and... 

Base plate is one of the important and sensitive elements of a structure which roles as a connector of force and moment in column to foundation joint and prevents from stress concentration in the joint area. As until now there has been several numerical and experimental researches conducted about base plate connections, but in practice for design, base plate is considered as a cantilever beam which undertakes compressive force and bending moment. In this method of design many important factors such as separation and deflection of base plate, interaction of base plate with bolts and foundation aren’t taken into consideration. Therefore there is an urgent need to design base plates considering... 

Dams are huge structures in which safety is a very important issue because a failure will result in loss of lives and finance. Several approximate equations for the approximate analysis of arch dams already exist. These equations are usually obtained by considering the behavior of the dam as a shell. Approximate methods are much faster in comparison to the exact methods and give young design engineers who do not have the experience of designing inside view of displacements, stresses and strains. The aim of this project is to compare the results of approximate analysis of arch dams with the results of finite element models and clarify the points of dams in which approximate analysis methods... 

This study presents an image processing technique for automatic strain and stress measurement in sheet metals. In order to measure the strain automatically, the sheet blank is electrochemically etched to create circular and rectangular grids. After press forming of the sheet, circular grids are deformed into elliptical grids and rectangular grids are deformed into quadrilateral grids. Different photos are captured for using in image processing technique. These photos are taken in different positions. Finally strain can be measured by processing these photos and the stress is obtained by using Levy-Mises flow rule. In this study, three methods of image processing technique are simultaneously... 

The application of computational fluid dynamics (CFD) has been growing rapidly in biomedical engineering. The altered hemodynamics inside the blood vessels plays a key role in the development of the arterial disease called atherosclerosis, which is the major cause of human death worldwide. Atherosclerosis is often treated with the stenting procedure to restore the normal blood flow. A stent is a tubular, flexible structure, usually made of metals, which is driven and expanded in the blocked arteries. The presence of non-biological device in the artery causes inflammation or re-growth of atherosclerotic lesions in the treated vessels. Several factors including the design of stents and type of... 

In this project, by using the image processing method, the strain rate in the deformed sheets is measured, and then compared with experimental results. Scratches are first drawn on the surface of the sheet. After the deformation, photographs of the surface are taken, by using image processing method as well as the use of special techniques, the strain is obtained fast with accurately. By determining the strain, tension will also be achieved through Levy Mises relations. In this project, by using this method, the strain is calculated on surfaces with simple geometry, such as sphere (spherical surface of the sheet in the FLD test), as well as surfaces whose surface geometry is unknown and... 

Nowadays, we know that many hydrocarbon reservoirs are fractured regarding this, the investigation of the properties of these reservoirs is necessary to predict the storage, production and the drilling methods. To identify fractured reservoirs, the fracture properties and their geometries under different conditions should be investigated. Besides, the evaluation of the behavior of induced fractures in distinct under ground conditions is very important. The Mechanical properties of the drilling bed like crack propagation, layer and mass rock is impactful in planning of drilling process and hydraulic fracturing operation. In this research, at first we introduce natural and induced fractures... 

Given the broad role of oil and gas playing in the world economy, finding the hydrocarbon reservoir that economically is affordable is quite significant. Some of the unconventional oil and gas reservoirs are important from the economic point of view since they produce insufficient hydrocarbon due to either low permeability or damage during drilling and production. Hydraulic fracturing is one of the most significant methods for improving the productivity of wells and reservoirs. Hydraulic fracturing acts by affecting on reservoir rock physic. In the current century, this approach has an essential effect in enhancing the permeability and production of reservoirs by creating, extending and... 

Drivers' behavior is an influential factor in more than 90% of driving accidents. Due to the increased traffic load due to the use of private cars, as well as traffic congestion restrictions for the use of private cars at large city centers, the use of public transportation means for transportation of goods and passengers in order to reduce traffic load is a very convenient option and it is sometimes necessary. Therefore, it is very important to examine the behavior and character of drivers of public urban vehicles in order to increase traffic safety. The purpose of this research is to present and develop a descriptive model that describes the behaviors leading to at-fault accidents for... 

Casing collapse is a long-standing problem in Kopal oil field, located at a distance of 60 km of east of Ahwaz, Iran. In this field, so far casing collapse has encountered in 18 well-bore out of the 56 drilled-well-bore (~32%) due to creep loading caused by salt flow, which resulted in tremendous economic loss. Among all the different set of factors leading to such a problem, the effects of the local stress distribution on the wellbore wall and casing (resulted from the in-situ stresses, and stress perturbation due to drilling), pore pressure, the casing quality and material, and the applied-cement type are important. In order to investigate these factors and their effects, they should be... 

The “hypothalamus-pituitary-adrenal” axis is one of the most important axes of the human body, and cortisol is one of its key products, which plays an essential role in the immune system, stress management, and many diseases. Appropriate modeling and simulation of this axis can help us to understand how the body reacts to stress and inflammation, to examine relevant diseases, and how drugs affect the body. In this study, by combining an axial model of the hypothalamic-pituitary-adrenal axis with a model of adrenal cells, a bi-level model including several time delays has been developed that can predict the effect of stress on this axis. Some parameters of the model have been modified through... 

There is many operational problems in the drilling industry. One of these basic problems is stuck pipe. This problem occurs with different intensities in different formations due to particles falling into the well, pressure difference in the formation and drilling mud and instability of the wellbore and creates conditions in which the drilling string can neither rotate nor move, so all Drilling operations are stopped so that according to studies, pipe sticking is one of the most important reasons for stopping drilling operations. This stop imposes millions of dollars of operational damage on oil services companies annually. Therefore, identifying and prediction of stuck pipe as a major... 

Stress is an integral aspect of human experiences, manifesting in various situations such as tension, anxiety, and specific diseases. Researchers globally are exploring innovative approaches to control stress, aiming to quantify and detect it. The quantification of stress levels using brain signals is a prominent focus in the field of medical engineering.In most studies, the classification objective revolves around two classes (stress-relaxation) or three classes (stress levels). Typically, these studies employ databases inducing stress and recording brain signals uniformly. While various stress induction methods have been used, the resulting brain connections are less discussed.This project...