Sharif Digital Repository

Thread connections are widely used in tubular downhole equipment. Connections are usually weaker than tubulars and their failure will result in very high cost. Thread connections of downhole equipment are divided into two groups: standard connections and premium connections. Standard connections, despite being widely used, have limitations and will loose their efficiency in complex loadings. According to the mentioned limitations, premium connections have been proposed according to the existing need related to improving the strength of the structure, proper sealing and resistance to galling. One of the most obvious applications of premium connections is in downhole tubulars that are... 

Powder metallurgy is one of the most important and most usable methods in industries. Nowadays, many of the specimens are made this way. In this method, after powder compaction stage, because of sintering in high temperature, crystallographical structure of the material changes. This change results in poorer strength than initial powde. In order to avoid change and decrease in powder strength, shock consolidation is used. In this research, because of complication of this phenomenon and final quality of the specimen, shock consolidation of metal powders is investigated and analysed. This phenomenon is modeled, simulated, analysed and optimized mathematically.Various methods are used to create... 

Nowadays, water and energy shortage is the main concern of many industries. Every saving that could be done is valuable. In the first step of this project, energy recovery devices that are used in reverse osmosis systems, are reviewed and advantages and disadvantages of each system are investigated. These apparatuses save energy by recovering high-pressure energy from leaving brine and reduce the energy consumption of the device. The main focus of this study is energy consumption of the device that is used for desalination of seawater in reverse osmosis systems and on this basis, different energy recovery devices are compared. According to the investigation, results showed that most of the... 

Inflatable packers have a great value in downhole operations due to their unique ability to expand to several times their initial diameter. These type of packers have a sealing element. This element is constructed of thin overlapped sheet metal ribs which are surrounding an inner tube. These overlapped ribs protect inner tube against the extrusion. The outer surface of this element covered by a layer of rubber. The outer elastomeric cover seals the annulus of the casing and isolates the zones in the well. In this study, some of the geometrical and material parameters effects on inflation and deflation of inflatable packers are investigated by numerical method. At first, for this purpose, the... 

Due to the relatively high freedom of selection of materials associated with a simple manufacturing method, a nonpneumatic tire (NPT) can be manufactured with low viscoelastic energy loss material. NPTs consisting of flexible spokes and the shear band are still at an early stage of research and development. An optimization study of NPTs’ geometry needs to be conducted, which is the objective of this thesis. Parametric studies and design of experiments (DOE) of an NPT are conducted with a hyper-viscoelastic finite element (FE) model to determine the effects of four design variables on rolling resistance, contact pressure and vertical deflection. Considering vehicle load carrying capacity and... 

Today, tens of millions of people on the planet suffer from heart disease. For the correct diagnosis and treatment of these diseases, there is a vital need for accurate scientific evidence such as various types of vascular and cardiac imaging. One of the applications of guidewires is in cardiovascular imaging. Of course, in addition to diagnosis, this device is also used in the treatment of disease. It should be noted that about 21 million central vessel catheters are performed annually on heart patients, of which about 16 million are performed using the seldinger method. Reportedly, unfortunately, 5% to 19% of these operations have had side effects and harm to the patient or failure.... 

Inflatable packers are a class of downhole equipments that are used for oilwell pluging operations. To set the packer inside the well, it is necessary to apply hydraulic pressure to it. By using the setting tool and installing an electropump in it, it is possible to transfer the fluid into the packer and supply the required pressure. In this research, an electropump has been designed and built that, firstly, is dimensionally suitable for the conditions of oil wells and, secondly, can have a good performance in the environmental conditions inside the well. This electropump, which can be used in a 2.125-inch setting tool, consists of a brushless direct current motor and a piston pump. To test... 

Congenital heart defects are a type of heart diseases that some babies get at birth. These diseases generally have symptoms such as shortness of breath, headache, impaired blood supply, hyperplasia of the lungs, enlarged heart, and so on. In the past, open heart surgery was commonly used to treat such diseases, which was a costly and risky procedure. But over time, occluders made it easier. An occluder is referd to a device that is generally minimally invasive in the area of the fault and could block it. The occluders are usually braided type, with inside polyethylene fibers, where tissues can grow and clogs the defect over time. Although occluders have greatly increased the success rate of... 

Oil and gas extraction has long been considered one of the world’s major industries, with the economies of many countries, particularly Iran, heavily dependent on these resources. As the complexity of operations increases due to deeper wells and more challenging extraction conditions, we are witnessing continuous technological advancements in this field. Innovative tools are being designed and utilized daily to support and develop these industries. Downhole equipment typically has a cylindrical shape and must be positioned at specific depths to perform their respective functions. Obviously, these tools must withstand significant axial loads and weight, especially as drilling depth increases.... 

Shape memory alloys (SMA) exhibit a number of features which are not easily explained by equilibrium thermodynamics, including hysteresis in the phase transformation and ‘‘reverse’’ shape memory in the high symmetry phase. Processing can change these features: repeated cycling can ‘‘train’’ the reverse shape memory effect, while changing the amount of hysteresis and other functional properties. These effects are likely to be due to formations of localised defects and these can be studied by atomistic methods. Here we present a molecular dynamics simulation study of such behaviour employing a two-dimensional, binary Lennard–Jones model. Our atomistic model exhibits a symmetry breaking,... 

Shape Memory alloys are a kind of intelligent materials developed in recent years due to their comprehensive use in medical, robotics, and other advanced sciences. Two main characteristics of them are shape memory effect and superelasticity put these materials in the category of advanced materials. Recently, the new branch of them attracted many studies which is the porous shape memory alloys. The importance of this class of material is related to their properties such as bio-compatibility, superelasticity and shape memory effect. Since shape memory alloys are usually expensive, a new field is developed known as functionally graded porosity distribution. This method is performed by... 

Nowadays, the lattice Boltzmann method has been widely used by scientists and engineers as an alternative to conventional numerical solvers for the Naiver-Stokes equations. The drag force decrease on the surfaces in industrial applications special in transport industries has always been of special importance. In the current research, the effects of the drag decrease has been investigated by making some rectangular grooves on the millimeter and micrometer scale on a flat surface that has been under external laminar flow of a single-phase fluid with the uniform type. Making grooves on the surfaces usually lead to change the contact area from the solid-fluid to fluid-fluid in the grooves area.... 

This research studies behavior and implementing of telescopic lead shear damper in structures. Telescopic lead shear damper (TLSD) is a type of metallic yielding dampers that can dissipated energy with usage of shear yielding of lead. TLSD is made from behind act of two lead shear damper (LSD) like a telescope. Lead shear damper composed of two coaxial steel pipes where their interfacial gap is filled with pure lead. The interface of lead and steel pipes are roughened in a threaded form to guarantee the no-slip condition across the interface. Due to stable and fat force displacement hysteresis loops of TLSD, this device can be used in structures subjected to wind, seismic, and other dynamic... 

When swellable elastomer are surrounded by suitable fluid, they absorb the fluid and swell. This capability is used to design different tools. For example, drug release devises, sensors and actuators, in microfluidic devises such as micro-valves and micro-mixers, and seal devises. Most of these devises are shaped cylindrically. Therefore, have a thorough knowledge about how cylindrical swellable elastomer behavior, give us a good vision about how to design such actuators. In this thesis we have used constitutive equation of such materials and have investigated behavior of cylindrical swellable elastomers analytically and numerically. Analytical investigation is focused of transient behavior... 

The coronary arteries of the heart are one of the most important arteries in the body's cardiovascular system, which carry oxygen and nutrients to the heart.Therefore, coronary heart disease is one of the most important causes of death in society. In this disease, when the adhesion of sediments and blood plugs to the walls of the arteries increase, the ducts become narrow and the circulatory system gets hard. As a result, the risk of heart attack and mortality increases.Due to the increase in mortality caused by coronary heart disease, working on treatment methods for this disease is important. Angioplasty and stent implantation in a vein are the latest treatments for this disease and have... 

The current research was conducted to investigate the sealing behavior of single-string and dual-string completion Packer. In order to transfer the oil from reservoir located underground to the surface, the string of tubings is used which is called oil well completion string. A typical completion string not only consists of tubings but also the other facilities such as safety valve, traveling joint, sliding side door and Packer as well. Some reasons including: the cost of drilling and challenges in setting wellhead equipment at some geographical situations, producing more oil and gas lead to extraction oil form more than one zone in the oil well. In addition, taking into the account that,... 

One of the most important tools in industries such as oil, gas, mining and groundwater is inflatable packers. These tools are used for plugging and zonal isolation of a well. The most important member of this cylindrical tool is the elastomer, which is reinforced by metal wire ropes. These cables are placed at an angle relative to the axis of the cylinder and are wound in a helix shape. At both ends of the tool are rings that hold the cylinder. After running the tool into the well and placed in the desired position, by a pipe connected to it, fluid is pumped into it. This increases the diameter or inflation of the tool, and the outer skin of the elastomeric cylinder contacts the well and... 

In the oil industry, after drilling an oil well and laying pipes, it is time for the hydraulic fracturing process. In the process of hydraulic fracturing, a fracture must be created in the casing pipe of the well. The reason for this is that the oil from the existing reservoir enters the well so that it can be extracted. The end of the well must be blocked to cause a fracture in the well body. The reason is that after creating a fracture in the casing pipe, proppant particles are pumped together with water inside the well to keep it open. For the proppant particles to be placed inside the cracks, it is necessary to create pressure in the fracture area. To create pressure in the fracture area... 

Smart materials are able to change their physical properties under various environmental conditions. Shape memory alloys (SMA) are relatively new smart materials that can respond to environmental stimuli e.g., heat, electricity, etc. Unique behaviors of SMAs, called shape memory effect and superelasticity, have motivated many applications in various fields of study (aerospace, medical, civil engineering, etc.). Although the behavior of SMAs is complicated, modeling and utilizing these materials have been receiving much attention in the past 20 years. Since a cable tolerate more tension than a wire or rod, the shape memory alloy cables could have a broad range of potential applications.... 

A new types of architected cellular materials are those with negative poisoon’s ratio named auxetic. This materials indicate unormal behavior under different loads as if they were stretched in one direction, they also expanded in other directions and if pressure is exerted in one direction, they are compressed in all directions. Auxetic materials can improve mechanical properties such as shear strength, strength to weight ratio, thoghness, energy and vibration dissipation and crack expansion due to fatigue.The useful features of this material have been taken into account in a variety of industries, including the automotive industry, in the manufacture of parts such as body and bumper,...