Sharif Digital Repository

In drilling operations, cost, time, and quality are the three factors to consider for evaluation. Drilling optimization means reducing project costs and completing them as quickly as possible while still meeting the standards. Due to the complexity and specificity of directional drilling and the increasing need for this type of drilling, optimizing the directional drilling operation is of great importance. Drilling rate of penetration and hydromechanical specific energy are considered as two main indicators of drilling performance in this thesis. In the first step, drilling rate of penetration is predicted using drilling data and machine learning algorithms and then single-objective and... 

Goal of this project was study of local microorganism ability in remediation of hydrocarbon contamination exists in contaminated soil around Sarkhun refinery.In first phase of this study, evaluation of bioremediation performance was done. Using a standard method in a 20 days period, the ability of local microorganism exists in contaminated soil was studied. In this study, 3 different nutrient ratios for 7 samples, 21 experimental samples, were used. Nutrient ratios as C:N:P were: 100:0:0, 100:5:1, and 100:9:1. Results showed that in this remediation period, minimum remediation efficiency in all samples with nutrients is 50% and also the best nutrient ration is 100:5:1. An empirical model was... 

Some of the thermal power plants use heavy fuel oil as an auxiliary fuel instead of the fuel gas, especially in the cold seasons. In these plants, in order to reduce fuel viscosity, heavy fuel oil is heated in several stages including fuel storage tank, connection lines and oil supply to burner by heat exchange with returned steam from the turbine, which can lead to fuel leakage into the condensates. This contamination is in addition to the contamination that has resulted from leaking seals on steam driven equipments, such as pumps and turbines. Reusing these contaminated condensates as boiler feed water can lead to coking of hydrocarbons and deposition of a hard scale on boiler tube walls.... 

According to, increasing use of energy in the world, issues such as increasing reenhouse gas’ emission, rising temperature on planet earth and air pollution have appeared Carbon dioxide is a major greenhouse gas that has a significant impact on increasing the temperature of earth. In recent years, attentions to carbon dioxide capturring and sequestration technologies have been increased. In this project molten carbonate fuel cell which is used as a new method for separating carbon dioxide from gaseous compounds of combustion process, is discussed. The aim of the project is to, investigate technical and
economic feasibility of using molten carbonate fuel cell for separating carbon... 

Considering high potential of solar energy and exhaustibility of fossil fuels in Iran, using solar energy seems to be inevitable. But one of the main problems in the application of these systems is high investment and maintenance costs. So, in this thesis, suitable solution is presented for decreasing cost and optimizing of a solar absorption refrigerator based on developed energy model. This system consists of two CPC solar collectors and a thermal energy storage system using phase change materials that provides input energy to the generator of absorption refrigerator. The exergy efficiency of system components is calculated by relations of energy model and exergy analysis. Then... 

This work presents the methodology to investigate Optimum Camera Installation Angle (OCIA)while employing the so called?Vision Based Navigation (VBN)? in urban areas.The approach is suitable for future general aviation aircraft as envisioned in Small Air Transportation System (SATS) as well as Unmanned Aerial Vehicles (UAV).Due to practical constraints, the work is limited to the maneuvers in the vertical plane while conducting Simultaneous Localization and Mapping (SLAM) technique.This technique was originated in robotics and is commonly used to guide both ground based and low speed aerial robots in unknown environments involving different types of obstacles. A variety of camera... 

In this thesis, plasam kinetic aspects causing production of high-energy super-thermal particles in strongly nonlinear perturbations, including relativistic electron waves and shock waves occurred respectively in astrophysical and laser produced plasmas, have been studeied. Importance of kinetic simulations in this area has been demonstrated. In this respect, passing serious challenges, we have prepared a kinetic particle-in-cell (PIC) code and applied it within our supplied computational-resources. Relativistic electron waves produced via interaction of laser with tenouse plasmas have been deeply studied. These studies have resulted in new findings in fluid description of these waves,... 

Hand in hand with the flourish of the biodiesel industries, glycerol has turned into an abundant waste chemical posing obstacles to their large-scale implementation. Devising measures for efficient transformation of glycerol into value added products is a promising alternative to its large-scale disposal into the nature that would also increase the competitiveness of biodiesel fuels. In this study, production of lactic acid (LA) as a valuable chemical with wide applicability is studied in a continuous process with glycerol as a cheap and convenient feedstock. In this regard, the state-of-the-art approaches in catalytic conversion of glycerol to LA are reviewed. A catalytic method using... 

According to general theory of relativity, collapse of matter under gravitational force leads to the formation of black holes. Considering the quantum effect shows that black holes have thermal radiation which cause them to evaporate. After a complete evaporation, the state of radiation can not contain all information of initial matter. In other word, this process does not obey unitary evolution of quantum mechanics. This is called the black hole information paradox, which has been one of the most challenging problem of theoretical physics for several recent decades. Recently, a deep connections between asymptotic symmetries, soft graviton theorem and gravitational memory effect has been... 

Regarding decreasing resources of fossil fuels and their increasing costs in addition to their environmental pollutions, today, producing bio fuels from wastes such as lignocellulosic materials is of great interest. A fundamental stage in conversion of lignocellulosic materials into bio fuels, such as bio ethanol, is the enzymatic hydrolysis of these materials to produce reducing sugars. Researches have shown high costs of this stage. Optimization of enzymatic hydrolysisconditions is a major step in economization of this process.In this work corn hull is used to produce glucose. Corn hull is a kind of lignocellulosic material that due to high carbohydrate content is used as substrate. Our... 

Emission of aromatic and aliphatic compounds to atmosphere is a major environmental concern for many urban societies. Catalytic oxidation of volatile organic compounds (VOCs) is an efficient and low operating cost technology for reduction of air pollution.
First, dispersed copper oxide nano-catalysts supported on almond shell-based activated carbon were prepared for catalytic oxidation of toluene in air. The Response Surface Methodology (RSM) was used to express the catalyst removal efficiency in terms of catalyst metal loading and calcination temperature. Calcination temperature had a significant effect on the catalyst activity only at high metal loadings (upper 8% wt.). Two different... 

One of the most significant problems of oil regions is salinity of the produced water extracted from the well. Penetrating the produced water through the surrounding environments of the oil well in recent years, plenty of environmental problems, especially agricultural ones have been caused in these areas. According to the increasing trend of water salinity during the time, one of the urgent action in the oil industry of the country should be finding a way to reduce the amount of dissolved salt in the produced water. The purpose to this project has been representing a more appropriate configuration for desalination of the produced water. Therefore, the water sample containing less than 70000... 

Biodegradation is an effective method for removal of hazardous organic compounds such as styrene and ethylbenzene from petrochemical wastewaters. Although using this method for wastewater treatment meets (satisfies) the industrial standards, still these methods have significant disadvantages. Active sludge systems can not be effective enough due to the volatility and recalcitrance of styrene and ethylbenzene and a significant amount of volatile organic compounds exists in the discharging air. In order to reduce or totally remove this amount of pollutants in the discharging air, Membrane Bioreactors are used. One of the main problems of these systems is membrane fouling. In this thesis the... 

Polyampholyte hydrogels are hydrophilic networks that contain both positively- and negatively-charged functional groups on their structure. Polysulfobetaines are the most important type of polyampholytes, which have been extensively studied. However, these hydrogels exhibited poor gel strength causing limitation of their applications. Consequently, much attention has been focused on the preparation of nanocomposite hydrogels with high gel strength and lower cost using organomodified clays. In this project, Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3-sulfopropyl) ammonium hydroxide (MPDSAH) were... 

Purpose of ongoing thesis is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption heat pump. At first, the solar absorption heat pump is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic Analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated.... 

Trash production in Iran is increasing. The majority of trash is being buried and that induces the emission of methane gas (CH4), which is a greenhouse gas. In this thesis, the aim was mostly to remove methane from greenhouse gases by applying several cheap and abundant substances. For this purpose, a biofilteration system was provided. It has been tested using two packings: straw and plastic. To provide the necessary materials for bacterium growth, a nutrient solution was used. The results of this work have revealed that plastic proved to be more effective than another substance and the removal percent obtained was about 61%. The result for straw was 42%. Furthermore, the experiments were... 

If wastewater is not properly treated, then the environment and human health can be negatively impacted. These impacts can include harm to fish and wildlife populations, oxygen depletion and contamination of drinking water. In the typical wastewater treatment process, the goal of primary, secondary and tertiary effluent treatment is to reduce or remove organic matter, solids, nutrients, disease-causing organisms and other pollutants from the treated wastewater before it is discharged to a body of water. Biological methods for wastewater treatment are much preferable for being more economical and environmentally friendly. Biological treatment of wastewater using algal-bacterial culture... 

The increase in CO2 concentration and its effect on ecosystem and global warming make carbon sequestration inevitable for now and future. Ex-situ carbonation of mineral ores is one of the studied sequestration methods. This method is permanent and safe in comparison with others. This process is carried out in four steps and two phases in this dissertation. At the first stage magnesium was extracted from its mineral silicate ore (Mixture of serpentine and olivine) by hydrochloric acid (HCl) and was dissolved in liquid phase as ion. After that the resultant leachate of extraction step was purified from unwanted ions extracted from minerals in two steps by precipitation formed by increasing pH.... 

Water-energy nexus approach is any water and energy interaction in a system to provide sustainable usage of resources. Quantitative model of interaction of water and energy in analyzing water-energy nexus is not comprehensive approach for solving all challenges facing this section. Qualitative analysis of water-energy nexus provides optimization and prioritization solutions in water and energy systems from other aspects. In present thesis two quantitative and qualitative aspect of water-energy nexus is considered. Initially, for quantitative modeling, interaction and relation of water and energy (watergy) with six principles to form WatErgy Reference System (WERS) was presented. The... 

The most important aspects of extensive air shower studies are finding energy, mass and the arrival direction of primary cosmic ray particles. In order for these parameters to be established, the core position of extensive air showers should be determined. In this thesis, a new method has been introduced that utilizes trigger time information of particle detectors for finding extensive air showers core location and for correcting plane wave front approximation to reconstruct their arrival direction. This method, in its simplest form, does not depend on density-sensitive detectors which are sensitive to the number of crossing particles. It is also independent of lateral distribution models....