Sharif Digital Repository

Drilling fluid is one the most important part of drilling operations in the oil and gas wells digging. From an economic point of view, almost 25 to 45% of drilling costs are allocated to drilling fluid. Drilling fluids consist of several components with different physical and structural forms which can be assumed as complex fluids. Optimum performance of the drilling process could be obtained through the dynamic fluid computation which requires a reliable mathematical model capable to predict transient-state and steady-state rheological behavior of drilling fluid. Generalized Newtonian models, such as the Bingham-plastic model, the power model, and the Herschel-Bulkley model, are the most... 

Despite of passing many years from invention of Computational Fluid Dynamics (CFD), simulation of the fluid-solid interfaces and free surfaces are still completely challenging and progressive problems. In addition knowing and understanding nanotechnology huge applications,modeling of nano-fluids have been became a priority for researchers. Adding importance of Non-Newtonian fluids (especially polymeric solutions) to this two subjects, triangle topics of this research becomes vivid. In this research tried to consider and examine behavior of Newtonian,Generalized-Newtonian, Viscoelastic and nano-filled viscoelastic fluids in one and two phase mediums. we followed mesh free methods which are... 

It is about half century passed from the invention and application of the polymer flooding. Although there are successful reports from the using polymer flooding, but there are problems that in some cases this process fails. For more insight on the problems and in order to improve
the efficiency of this process the conceptual understanding of the process is required. More conceptual understanding from this process, requires investigation in pore scale. In the presenting investigation, the flow of Newtonian and non-Newtonian fluids in the single phase and two phase form and in pore scale are simulated using finite volume method. Because, the finite volume method is used in very... 

to achieve a stable elimination of colloidal suspended particles, polymer flocculants such as polyacrylamide and its derivative have been more used. To improve the performance of removing turbidity, reducing settling time, and better dewatering from sediments, hydrophobic styrene monomer copolymerized with acrylamide monomer. In this study the copolymer of acrylamide and styrene was synthesized by inverse emulsion polymerization, then this copolymer undergoes hydrolysis to form anionic groups on the polymer backbone. FT-IR, H NMR, and TGA analyses were carried out to investigate the structure of the copolymer. To evaluate flocculation, turbidity tests, zeta potential, and sedimentation rate... 

The present work focuses on the sustainable development of an intelligent self-healing anticorrosion coating using nanocontainers based on the aluminium oxide nanostructure-pomegranate peel extract-Ce3+ (Ce-PPE@Cat). The Ce-PPE@Cat nanopigment was introduced into the epoxy film (Ep) to achieve a smart barrier/ self-healing anti-corrosive property. To this end, a couple of characterization tests, including FT-IR, TGA, and, BET have been carried out to investigate the Ce-PPE@Cat nanopigment structure/composition. The effectiveness of the anti-corrosion performance of the established coatings was confirmed by EIS, FE-SEM, and accelerated salt spray test. Furthermore, EIS studies revealed that... 

In this study, the effect of molybdenum disulfide nanosheets on the rheological behavior of suspensions was investigated using a polyethylene glycol matrix and glass grain fillers with a particle distribution of 60 to 103 microns. Crude molybdenum disulfide was obtained by single-layer and multilayered molybdenum disulfide nanosheets with thicknesses between 50 and 100 nm using acid, oxidation and heat shock methods. This claim was verified by various tests such as FT-IR, FESEM,EDS, TEM, DLS, XRD and so on. Subsequently, using 10 to 40% volumetric glass beads were prepared from the sample matrix. Stirring and ultrasonic, rheological behavior of these suspensions were investigated using... 

In this research UHMWPE/MWCNT nanocomposites with different concentrations of nanotubes (0.5, 1.5, 2.5, 3.5 wt %) were prepared via in situ polymerization using a novel Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Multi wall carbon nanotubes functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 accompanied by triethylaluminum constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Support of catalyst on MWCNT was investigated using Fourier Transform Infrared Spectroscopy (FTIR). The results confirmed interaction between catalyst and hydroxyl groups on the surface... 

The the nervous system as a most comlicated body system , plays an important and vital role for the body systems. damage to the peripheral nervous system result in nervous system disorders which claissified to Neuropraxia, Axonotmesis and Neurotmesis based on damage itensity. tissue engineering considered as one of the repairing nervous damage way, which by creating 3D substrat (scaffold) with proper physical structure, increses possibility of adhesion, growth and proliferation of cells to increase regeneration rate of damaged nerve. in this study, a combination of dual-electrospinning and rolling the spun film used to preparate a nerve guidance conduit (NGC) based on gelatin, PCL and... 

Among the methods for increasing chemical oil extraction,the polymeric flood method has the most commercialization capability.However,most commonly used polymers such as Hydrolyzed Polyacrylamide (HPAM) are not able to withstand high levels of salinity and high temperatures.To overcome these problems,in this project,new types of polymer nanostructures were synthesized with hydrophobic groups consisting of styrene (hydrophilic monomer) and malic anhydride (hydrophilic monomer) acrylamide (hydrophilic monomer). These polymers were synthesized by reversible mini-emulsion by adjusting the synthesis conditions for the purpose of producing the terpolymer with suitable conditions for tolerating... 

In this research UHMWPE/FUMED SILICA nanocomposites with different concentrations of nano fumed silica (0.5, 1.5, 2.5, 4.5 wt %) were prepared via in situ polymerization using a novel Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Fumed Silica functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 accompanied by triethylaluminum constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Scanning Electron Microscopy (SEM) images also certified very good dispersion of fumed silica throughout PE matrix. Intrinsic viscosity measurements showed high molecular weight for... 

The use of polymers in the EOR process is very common. Most of these polymers are sensitivity to temperature, salt, and the presence of bacteria. Among these materials, hydrolyzed polyacrylamide (HPAM) is the most widely used. Due to the sensitivity of HPAM in harsh conditions like temperature and salinity of the environment, modification of this polymer by hydrophobic groups can be very effective. Hydrophobic-hydrophilic associative polymers have shown unique rheological properties and high thermal stability, which is due to the presence of a small percentage (up to two percent) of hydrophobic monomers in their structure. Despite these excellent properties for acrylamide copolymers... 

In recent years, the use of polyurethane foams has been of interest for many researchers and craftsmen. Polyurethane foams, due to their excellent properties, can be used in important applications such as advanced military industries, insulation and those requiring strength and maneuverability. The aim of this research project is to produce polyurethane / sodium silicate or nano-silica nanocomposites. Prior to the fabrication and synthesis process of polyurethane containing sodium or nano-silica, deposited silica nanoparticles were synthesized using high-rubbed sodium silicate and sulfuric acid, followed by various tests including XRD, FE-SEM and BET to verify It was done. Sodium silicate... 

The use of polyether ether ketone (PEEK) in bone implants is limited due to a lack of cell adhesion and proliferation. Therefore, in this study, we modified the surface of PEEK with a nanocomposite coating containing piezoelectric and bioactive properties. Sulfonated PEEK with suitable mechanical and hydrophilic properties along with polyvinylidene fluoride was used as a biocompatible polymer with piezoelectric properties for coating. Also, nanohydroxyapatite was used as a bioactive material, and carbon nanofibers with significant mechanical and electrical properties were used in the nanocomposite. The surface was sulfonated as an intermediate layer to improve the connection between the... 

Understanding the properties of crude oil and the phenomena arising from this precious matter has always been of considerable importance. One of these important phenomena is emulsion, which is well-known in a great number of crude oil-related processes such as drilling, well completion, production, transportation and even the processing units in the refinery. One of the most important properties of crude oils and their emulsions is their flow or in other words their rheology. Therefore, in this project has also been tried to investigate the rheological behavior of crude oil and water in crude oil emulsion, experimentally and theoretically. The experiments were carried out using two crude... 

Among chemical enhanced oil recovery (CEOR) methods, polymer flooding has the highest commercial potential. However, the most widely used conventional polymers such as partially hydrolyzed polyacrylamide (HPAM) are not applicable for high temperature and high-salinity reservoirs. To overcome above mentioned problems, in this work, a series of water- soluble hydrophobically modified polymers (HMPs) nanostructures comprising styrene (hydrophobic monomer) and acrylamide (hydrophilic monomer) have been produced. The copolymers have been synthesized using inverse miniemulsion synthesis method by adjusting synthesis conditions to optimize solution characteristic of copolymers for applying under... 

In the preparation of nanocomposites, the multi-walled carbon nanotubes (MWCNTs) functionalized by hydroxyl groups were used. Subsequently, the polyethylene/multi-walled carbon nanotube (PE/MWCNTs) nanocomposites were prepared via in situ polymerization technique. In this study, effect of MWCNTs on the thermal degradation of these PE/MWCNT nanocomposites was investigated; the thermal degradations of pure PE and PE nanocomposites with different concentrations of nanotubes (0.5, 1.5, 3.5 wt %) have been studied by using thermal gravimetric analysis (TGA). Samples were heated to 700˚C at different heating rates (5, 10, 15, and 20˚C/min). TGA was used to investigate the effect of the MWCNTs on... 

Among chemically enhanced oil recovery (CEOR) methods, polymer flooding has the highest commercial potential. However, the most widely used conventional polymers such as partially hydrolyzed polyacrylamide (HPAM) are not applicable for high-temperature and high-salinity reservoirs. To overcome above-mentioned problems, in this work, a series of water-soluble hydrophobically modified polymers (HMPs) nanostructures comprising 2-vinyl naphthalene (hydrophobic monomer) has been produced by freestyle method (without Surfactant), micellar (with Surfactant). The size of the particles was investigated using scanning electron microscopy (FE-SEM) and optical scattering (DLS). Results from FT-IR... 

In this work, sulfonated polycarbonate (SPC ) membranes with different acid contents have been prepared by conducting sulfonation reaction at room temperature using Chlorosulfonic acid (CSA) as sulfonating agent at different concentration of acid in reacting solution. The SPC membranes were obtained by casting from 10% solution of SPC in chloroform at room temperature. The prepared membranes were characterized using Ion exchange capacity (IEC), and degree of sulfonation (DS), Fourier Transform Infrared (FTIR), NMR spectra, Thermal Gravimetric Analysis (TGA) and Water uptake. The obtained results showed that with increaseing in Chlorosulfonic acid content in sulfonation reaction IEC and DS of... 

With the rapid increase of energy consumption, energy problem has been a global issue, which must be faced with and solved. One way to prevent energy consumption is to reduce drag in the flow inside the pipes by using polymer additives; Because the Transportation of liquids using pipeline technology has its limitations, since turbulent flow inside the pipe involves a loss of energy. The net effect of this is that increasing the energy applied to the flow does not increase the flow rate. For this purpose, copolymers and terpolymers of hydrophilic acrylamide monomers along with hydrophobic styrene and hydrophilic maleic anhydride monomers were synthesized by reverse emulsion polymerization... 

In order to protect the corrosion of steel, a self-healing epoxy nanocomposite containing modified graphite carbon nitride (g-C3N4) and ZIF-67 was made along with benzotriazole (BTA) and cerium inhibitors. To increase the efficiency and also to increase the duration of use of inhibitors, it is better to load these inhibitors on containers such as MOFs. One of the useful MOFs for this purpose is ZIF-67, which has a high specific surface area that allows the transport of inhibitors with high capacity. But these containers fail after some time, so to improve the physical properties of the coating systems, g-C3N4 was also used as a mineral material, which of course was also used as a filler....