Sharif Digital Repository

One of the most common methods for enhancing oil recovery is gas injection. Because of greenhouse effect and environmental problems, carbon dioxide can be used as injected gas. Low viscosity and high relative permeability of gas make the gas injection as an ineffective EOR method. Foam injection is a good replacement because its mobility is much higher than gas. Usually surfactants are used as foam generator agent but the generated foam is not so stable. Using nanoparticles can improve foam stability for a longer time. In this research study fly ash particles is used as a new stabilizer agent to improve carbon dioxide foam stability. This particles are made of silica, aluminum, iron …... 

In this treatise, it will be shown that the subject of faith is the subject who loves God and in showing her love to God, she sacrifices her dearest things in the world. By doing that, she would free herself from everything that mind herself. She doesn’t do this action to be given a better reward by God. Her motivation for performing this action is nothing but love. Meanwhile, the subject of faith hopes God to respond to her love and engage in an I-Thou relationship with her. Now, her hope would be justified when God plays an active role in the world and admires her action, i.e., when eros can be attributed to God  

This thesis is going to investigate the ontological foundation of Science and Tool. To this aim, it refers to Heidegger’s works especially the Being and time. Heidegger gets involve in analyzing Science in the Being and Time. He emphasizes on importance of establishment of a fundamental knowledge which should ontologically recognize basic concepts and methods of Sciences, to cause a real progress in sciences. Heidegger also asserts that the Mathematical interpretation of the world is not a fundamental, and it must be replaced with phenomenological interpretation, which clarifies the ontological foundation of the theoretical view, and regards to all aspects of world’s existence. In this... 

Uranium separation from other metals in ore and nuclear waste is one of the most important stagesin nuclear fuel cycling. Solvent extraction is the common method for uranium extraction that reagent plays important rule in this technique. In this investigation, uranium solvent extraction is carried out by Cyanex 301 as reagent from nitric acid. At beginning, equilibrium batch extraction was carried and the effect of parameters such as pH, reagent concentration, temperature, shaking time of two phases, volumetric ratio of two phases, diluent and nitric acid concentration on extraction was investigated and optimum value of parameters was calculated. Uranium concentration effect was also... 

Dispersed phase holdup has been measured in a 75 mm diameter pulsed disc and doughnut extraction column for three different liquid-liquid systems. The effects of operational variables such as pulsation intensity and dispersed and continuous phases flow rates on holdup have been investigated and found to be significant. The existence of three different operational regimes, namely mixer-settler, dispersion, and emulsion regimes, was observed when the energy input was changed. The results indicated that the characteristic velocity approach is applicable to this type of extraction column for analysis holdup in transition and emulsion regions. Empirical correlations are derived for prediction of... 

In the current work, jatropha oil was studied in the hetrogenious solid catalytic transesterfication reaction. For this perpous, KOH/CNT catalyst which was prepared by dry impregnation method was used. SEM, XRD and TGA were applied for the catalyst characterization. The results showed that for the KOH/CNT catalyst, by increasing the loading of KOH, the activity of the catalyst increased and the most active catalyst was prepared by 20% loading of KOH. The optimum conditions for transesterfication reaction in the percense of this catalyst were: 4.7% catalyst weigth and the 24.5 molar ratio of methanol to oil and also the reaction time of 2 houres which the rate of reaction at this time is... 

Entrance of air to close water conduits occurs in many ways. This phenomenon makes displeasing effects on water transport structures. Two-phase flows in closed conduits are studied experimentally, numerically and theoretically. Even after decades, due to the complexity of the subject, these studies still require development and reformation. Numerical and theoretical two-phase models are often limited to a special regime of flow."Volume Of Fluid"(VOF) is a model for non-mixing two-phase flows. "Fluent" software uses this model in this field of flows. Volume of fluid is used successfully in some problems like dam break or rising bubbles. Main disadvantage of this model is distribution of the... 

In this project, polymer nanocomposites containing graphene oxide were prepared and used for adsorption of several cationic and anionic dyes. In most cases, these nanocomposites were prepared as three-dimentional polymer networks which contain graphene oxide. Nanocomposites with direct grafting of polymer chains onto the surface of graphene oxide were also prepared. Graphene oxide is an oxidized carbonaceous material with unique properties. This material has high surface area, good mechanical strength and various functional groups. Polymeric compounds with different functional groups, structures and properties can be prepared and used. By preparing composites of graphene oxide and polymers,... 

Common fracture treatments include open reduction and intramedullary nailing technology. However, these methods have disadvantages such as intraoperative X-ray radiation, delayed union or nonunion and postoperative rotation. Robots provide a novel solution to the aforementioned problems while having new challenges. The robotic system used in the study by providing more precise motion and exerting higher amount of forces makes the operation procedure more straightforward. In a normal operation 300-400 N of extension force would be needed which is fully provided by the surgen which leads to physical his/her (khastegi), by using the robotic system however, this force is simply provided without... 

Moderate and Intense Low-oxygen Dilution(MILD) is the new member of combustion field. Highly preheated reactants and lowering the oxygen level in MILD combustion has some promising advantages. In this study the MILD burner, Jet-in-Hot-Coflow(JHC), is taken as the main test case. In this Research, Eddy Dissipation Concept combustion model ,introduced by Magnussen et al,is investigated in detail and governing equations are re-extracted. EDC combsution model due to moderate compuational cost in comparison with other combustion model and well prediction ability has drawn attention. Simulations on the Jet-in-Hot-Coflow(JHC) has shown the promising performance of the EDC combustion model. It seems... 

Worldwide interoperability for Microwave Access (WiMAX) is one of the most dominant cell-based broadband wireless metropolitan access technologies. Packet scheduling algorithm specifies the packet transmission order. In WiMAX standard, packet scheduling algorithm is not defined and its efficient design is left for developers and researchers. The existing researches in the scope of uplink packet scheduling, which is the most challenging packet scheduling scheme, consider only one cell. However the uplink available resources might not be enough when there are many packets that should be scheduled. To solve this problem, we propose an algorithm that uses the load balancing mechanisms that are... 

Trac classication in today’s high-bandwidth networks is challenging, resource consuming, and inaccurate due to the high volume, velocity, and variety aracteristics of the network trac. Trac aracterization and Application identication teniques are widely addressed in the current literature. Due to the massive volume and streaming data in recent years, stream algorithms have been considered by many researers in dierent areas. Online application detection is an issue that has been addressed less frequently in literature. In this thesis, we investigate the performance of 10 dierent stream classication algorithms along with traditional classication algorithms. To generate a robust classier for... 

The purpose of the present study is to plan an industrial system, over a period of 10 years, so that over time, while supplying the required demand, to optimal resource utilization with regard to material reuse and recovery flows of losses as well as the use of renewable resources move to implement the concept of a circular economy. One of the main incentives for the transition to a circular economy is carbon tax policy, which has been taken into account. The results of the decision-making model based on cost and flow constraints indicate that the use of carbon dioxide as a by-product of Pars Petrochemical Extraction Unit in order to produce urea in Pardis petrochemical industry in addition... 

Research on the impact of high temperatures on the mechanical properties of concrete is crucial for fireproof design, safety assessments, and repairing fire-damaged structures. However, there is a lack of research on the effects of water re-curing on thermally damaged concrete. This study aims to explore how high temperatures and water re-curing affect the compressive behavior of concrete with varying percentages of rice husk ash (0, 4, 8, 10, and 12%). The compressive behavior was assessed by analyzing stress-strain responses and parameters such as compressive strength, modulus of elasticity, strain at peak stress, ultimate strain, absorbed energy, failure mode, and visual observations.... 

In the cloud computing environment, although many processing resources for application software with the volume of calculations The above is available, but it may not work for software that is sensitive to latency. In fact, due to the large distance between users and end devices to cloud servers, sending requests And the required data to the data centers requires a high bandwidth and therefore the data transfer time is also significant. In addition, cloud computing in platforms such as cloud-based IoT architecture faces other challenges such as connectivity, resource limitations of end devices, and security. In order to solve the challenges in the cloud computing environment and respond to...