Sharif Digital Repository

The rheology of oil well cement (OWC) slurries is generally more complicated than that of conventional cement paste. In order to contend with bottom hole conditions, a number of additives are usually used in the OWC slurries. The objective of this research is to develop a fundamental understanding of the important mechanisms that affect the properties of OWC slurry such as rheological properties, free water, compressive strength and thickening time incorporating various chemical and mineral admixtures. The partial replacement of OWC using different nanoparticle weight percent has been proved to be a promising method. The mechanisms underlying the effects of chemical admixtures on the... 

Hydraulic fracturing process as one of the most important ways to inhanse of production requires careful study and investigation and due to its importance has been studied for decades. The effect of this process on the production at oil and gas industry has many complexities and these complexities with the complex structure of natural gaps, would be multiplied. In this thesis effect of hydraulic fracturing operation on the production of natural fractures at naturaly fractured reservoirs from two aspects of hydraulic and geomechanics will be investigated. First we provide models for fractures network by using UDEC software after that investigate the effect of hydraulic farcture on the natural... 

Foam concrete is a new covering layer that can be used for several purposes in civil constructions and because of its unique physical specifications, produces a light concrete in which is isolated against thermal conductivity ,with required strength and favorite quality.This cover is made of cement , sand ,water and foam(chemical substance that produces foam) . The foam is mixed with water in a special machine (mixer) with a high speed centrifugal rotation and produces very small stable bubbles called foam. While cement and sand are mixed in special mixer, makes a fluent concrete that can be used in place, metallic or plastic molds. After dehydration, in accordance with percentage of... 

Importance of consumption of energy and extraction of energy from its reserve in all over the world and whole industries lies in the fact that availability of fossil fuels is limited and demand of it in industries is huge. For the sake of life of industries, each industry sector should be expanded quantitatively, so growth of energy consumption is inevitable. Development of cement industry is effected in total energy demand and harmful pollutants in whole the country and limitation in energy supply and low level of reliability in energy supply cause the increase of cement production cost which will be effected negatively in relativity principle of prioritization in cement export due to... 

This research deals with numerical simulation of triaxial test to determine behavior of non-cemented and cemented ballast aggregates used in base and subbase of roads and railroads. Ballast aggregates, thanks to their high strength and durability, are widely used in various fields including dam, river, road construction, and railway. One of the most widespread uses of this material is in the road body, and according to the recommendation of the British Highway Center, the materials used in the road body are well-graded gravel with the maximum size of 20 mm. Cement is also used as a corrective material to enhance the performance of road bodies. Therefore, knowing the characteristics of these... 

Casing failure is one of the mainly problems of hydrocarbon fields that may cause wells out of service and impose heavy costs on oil companies. There exist many theories that may cause casing failure including: the plastic behavior of surrounding formations, the effects of reservoir depletion, over-pressured formations, weak cementing operations, fault activation, and local stresses applied on casing. In salt-rich formations, creep behavior can be the main cause of casing failure, too.The purpose of this study is to evaluate the causes affecting casing failure via experimental studies and numerical simulation with the focus on the conditions governing south-west Iranian oil fields, where the... 

The purpose of the present study is to develope an optimal model for analysis the impact of implementing a heat recovery system in a cement production line. For this goal, the energy reference system of a cement plant has been prepared, mass and energy balance sheets of the cement factory with dry production method, the characteristics of two high-energy streams have been identified in order to estimate the potential of heat recovery. Regarding the temperature range of the main hot streams, an appropriate cycle for generating electrical power from the lost heat, the Rankine cycle with organic fluid (ORC) has been formulated. The main question in the present project was how to relate the... 

Cement as a major industrial product plays an important role in the growth and development of countries. However, the economic condition in Iran has led to a decline of the production of this strategic product in recent years. At the moment, most of cement factories are faced with overproduction and inefficiency due to high production cost, broken financial situations, high energy cost, wages and overhead cost that have led to a serious crisis in cement industry. Scientific research must be carried out to find solutions to the present critical situation in the cement industry. The application of Lean Management System leads to a sustainable development of cement industry.In this study, a... 

Hip replacement surgery is performed with the aim of relieving pain and restoring the normal function of the joint for patients who are in the final stages of arthritis. Standard prostheses offered by implant manufacturers come in a wide variety of models and sizes to meet the needs of patients. However, these commercial prostheses may not be suitable for patients with significant bony abnormalities, leading to implant instability and loosening. In such cases, a suitable solution is to use customized implants that are specifically designed to match the patient's unique anatomy. The purpose of this research was to design a customized cement stem for hip joint replacement surgery in patients... 

One of the most important parts of a cement factory is the cement rotary kiln which plays a key role in quality and quantity of produced cement. In this part, the physical exertion and bilateral movement of air and materials, together with chemical reactions take place. Thus, this system has immensely complex and nonlinear dynamic equations. These equations have not worked out yet. Only in exceptional case; however, a large number of the involved parameters were crossed out and an approximation model was presented instead. This issue caused many problems for designing a cement rotary kiln controller. In this thesis, we employed a nonlinear system identification method for identification,... 

Method of Prompt Gamma Neutron Activation Analysis (PGNAA) is useful for controlling some massive production processes such as cement industry and mineral materials. Difficulty of other methods of analysis such as XRF comparing with PGNAA is that mass of sample is small and it doesn’t determine heterogeneity of mixture. On the other hand, need to sampling is also another problem of these analysis methods because sampling is terminated and it doesn’t supervise on production continuously, in fact its quality can’t be revealed simultaneously and there is a long time between sampling and control of process. Usually, analysis methods such as XRF are useful for processes that are controlled... 

Superabsorbent polymers are mainly used in baby diapers and in agriculture. A less known emerging and potentially important application is the internal curing of cement based materials. About a decade ago, pioneering works demonstrated that using SAP in concrete reduces autogenous shrinkage and cracking, and improves hydration of the cement matrix. However, problems like workability reduction, and deterioration of mechanical strength of the mixture are reported. In this thesis, nanocomposites using nanosilica and acrylic monomers were prepared and used to address the above problems. Nanocomposites exhibit enhanced mechanical strength and reduced sliding friction, compared with conventional... 

PMMA bone cement lacks biodegradability and the ability to bond with surrounding bone tissue. Therefore, the development of a new generation of bioactive bone cements that are biodegradable and possess adequate mechanical properties as well as desirable setting time is receiving remarkable interest.In this study, we have developed novel mineral-based bioactive bone cements. Our mineral bioactive bone cements were composed of Calcium Sulfate Hemihydrate, Bioactive Glass, and Tricalcium Silicate. Firstly, a binary system composed of Calcium Sulfate Hemihydrate and Bioactive Glass was optimized based on mechanical and setting behavior. Secondly, Tricalcium Silicate was added to the powder phase... 

The incidence of skeletal diseases such as osteoarthritis and its progression and the need to use knee replacement implants have significant effects on the quality of life. With the improvement of living conditions and the prolongation of the average life expectancy of the society and the aging of a large part of the society, the concern about the increase in the incidence of skeletal diseases and the need to use alternative implants increases. On the other hand, many conditions such as osteoporosis and accidents lead to fractures and cavities in the bones. Bone cements are one of the most widely used materials in orthopedic and spinal surgeries.The aim of this study was to construct a... 

The natural tissue of the bones consists of organic and inorganic parts. The bone mineral part contains calcium phosphate and its organic part is mainly of collagen fibers. The combination of these fibers and calcium phosphate makes the bone flexible and resistant to stresses. Many conditions, including osteoporosis and crashes, lead to fractures and cavities in bone. Bone cements are the most used materials used in orthopedic surgeries and spinal cord.The purpose of this study was to synthesis acrylic bone cement with properties determined by ASTM F 451 and Iso5833 for orthopedic applications, including joint replacement. Polymethyl methacrylate polymer was synthesized as the main component... 

Every year hundreds of thousands of lives are taken away worldwide by natural disasters such as earthquakes. Walls made of concrete blocks or bricks, are amongst the most vulnerable type of walls, which tend to collapse during an earthquake. Due to their good sound and thermal insulation properties, unreinforced masonry (URM) walls are widely used in partitioning many of the commercial and residential buildings worldwide. URM is considered one of the most common types of partition wall systems in many of the school and hospital buildings and commercial buildings.URM partition walls are known to have very low drift capacity in seismic events and the failure mechanisms are known to be mostly... 

This project is providing appropriate software which could manage maintenance activities in a plant. All sections of the software have been designed in a way that can ease the management of maintenance activities. There are about 100 forms in the software that have been designed according to the forms which are being used in some Iranian cement plants and other maintenance software and also what we recognized important to be added or designed. One of the most important aspect of this software is the analytical section of the software where the user can get analytical reports from the software and based on the reports judge about the status of the plant and make new decisions in order to... 

Ion exchange resins are widely used in nuclear industries. These spent resins result in the production of a large amount of low and intermediate level radioactive wastes, therefore, the treatment and immobilization of spent ion exchange resins are the major problems in the development of nuclear power plants.In this research, in a laboratory scale, we tried to find the suitable procedure and formulation to immobilize a specific group of cation-exchange resins which is used in Bushehr nuclear power plant (AMBERLITE IRN-97H) in the cement matrix. The solidification matrix consists of five constituents: anti sulfate slag type portland cement, cation-exchange resins, diatomite, sodium hydroxide... 

Collapsible soils have been encountered in many parts of the world such as Gorgan (a city in North of Iran). In these soils, sudden and large volume changes occur while the water content, loading pressure or both, are passed a threshold limit. One of the serious problems that may occur in the structures constructed on collapsible soils is the catastrophic settlements resulting from increase of water content in the soils. In this research, improvement of mechanical properties of loessial collapsible soil taken from Gorgan has been investigated using biocementation method. There are some microbial processes that can lead to biocementation, which one of them is microbially induced calcite... 

Cemented material dam(CMD) are a type of dams constructed using cement-based materials. They are situated between earth dams and roller-compacted concrete (RCC) dams and are used in irrigation and hydropower projects. These dams are known for their high strength and stability and can be easily built on various foundations, including weak foundations. One of the significant advantages of cemented material dams is their reduced environmental impact, leading to less damage to surrounding lands and improved environmental sustainability. Considering the mentioned advantages and appropriate locations and foundations for dam construction are used, building cementitious material dams on soft...