Sharif Digital Repository

In this thesis, unconstrained convex quadratic optimization problems subject to parameter perturbations are considered. A robustification approach is proposed and analyzed which reduces the sensitivity of the optimal function value with respect to the parameter. Since reducing the sensitivity and maintaining a small objective value are competing goals, strategies for balancing these two objectives are discussed. Numerical examples illustrate the approach  

The goal of this research is to optimize the parameters of a process through which it would be possible to separate and recovery a considerable portion of ammonia nitrogen available in anaerobic digestion effluent slurry. To achieve this goal, after completing the construction of batch setup (including anaerobic reactor and stripper) and after the digestion of (cow and poultry manure) , the experiments of separation on amounts 9, 10, 11 and 12 of pH and on temperature 14, 25, and 38 celsius degrees were done on digested slurry. Then, the resulting equations of the experimental outcome fitting were used in the optimization of parameters. The results showed that the amount of the parameters of... 

Due to pollution and destructive effects on the environment, while consuming a large amount of fossil fuels that can be converted into high value-added products, gasoline cars are gradually replaced by electric cars. Modern electric vehicles are generally designed and manufactured on the platform of gasoline vehicles. In the present study, it is tried to design three models of electric vehicles based on the SAINA vehicle. Initially, for the first model, an electric motor instead of the SAINA gasoline engine is employed to provide the power required for the vehicle. Then, for the second model, two electric motors are used namely one in the rear axle and one in the front. The third model uses... 

Recently, parametric excitation has been proposed and experimentally proven to provide micro gyroscopes with robustness to parameter variations and enhancement of sensitivity. harmonic excitation gyroscopes are very sensitive to response of a resonance at the resonant frequency; therefore it has to be created accurately. However, parametric excitation gyroscopes are not sensitive as a result of wide bound of frequency at drive mode, accordingly it is not necessary to be formed accurately in the same way as harmonic excitation gyroscope.
The produced stress at combs have a significance effect on robustness, sensitivity and calibration curves of parametric excitation gyroscope, as a... 

In present research, a new system of energy extraction from water flow has been studied and optimized. This semi-active energy harvesting system consists of an airfoil that is connected to the generator by an arm. The passage of water causes the airfoil to move, so the hydrodynamic forces on the airfoil will cause the arm to move and finally the generator. In this research, complete dynamic modeling of this energy extraction system including generator, airfoil, controller and actuator modeling is presented and the governing dynamic equations are extracted using this modeling for dynamic simulation. Two dimensional fluid simulations have also been performed using fluent software. Finally, in... 

Nowadays with the extension of industry and factories as well as different kinds of plants, a wide range of pollution and circumference hazardous has been entered to the people`s life. Industrial wastewater has been always a threat for health of our environment and efforts for reducing its dangerous effects are still under studies. Dairy wastewater is one of the main branches of food industrial pollutions and it has been studied in this specific project. The goal was to reduce the Chemical Oxygen Demands (COD) of dairy wastewater with oxidation of Titanium Dioxide Nanophotocatalyst oxidation under UV irradiation. Among the various methods for synthesizing of this Nanophotocatalyst, the... 

In this project, an online controller design method based on parameter optimization is presented. The structure of controller is chosen to be the Internal Model Control (IMC). The cost function and constraints which include both time domain and frequency domain functionals are calculated directly from measurements of system’s output in order to reduce the effect of uncertainty in model estimation and controller design. The controller design problem is formulated as a convex optimization problem with ellipsoid algorithm used for its solution. The model of the system and a worst case upper bound on remaining uncertainty in model due to measurement noise, along with unmodeled dynamics of the... 

Condensation from a gaseous phase is a common method for the fabrication of metallic nanoparticles. Electromagnetic induction furnaces are the most common equipment used for this method. Since the sample doesn’t touch any foreign object, this method is one of very few ways to synthesize ultrapure nanoparticles. However, a major setback of this method is its low production rate.One of the only workarounds to this issue is to increase the melt’s surface area so as to present a larger surface for evaporation. In the common setup for this furnace the molten sample takes on a spherical shape which unfortunately holds the lowest surface to volume ration of any shape. The endeavor in this study has... 

With the production from the reservoirs, the amount of in-situ oil storage has decreased and there is a need to increase oil recovery (EOR) from the reservoir. Increased oil recovery (EOR) includes operations such as acidizing and hydraulic fracturing. Considering the economic and high operational costs and geomechanical complexities, as well as the technical progress of hydraulic fracturing and its future; It is necessary to manage hydraulic fracturing operations optimally. This research is about hydraulic fracturing and its main goal is to optimize the parameters of the fracture or the geometry of the fracture. The research study was carried out on the Bangistan Reservoir located in the... 

Diffuse tensor imaging or tractography is a useful method for tracking the axonal tracts pathways within the brain white matter by monitoring the movements of water molecules along the axons. The higher the level of the tissue anisotropy, the more accurate the pathways can be estimated. But in the swelling regions around an edematous tumor, the excess of watery fluid disrupts the directional movement of water molecules, and consequently, the diffuse tensor imaging is unable to track the pathways. This impairment should be resolved by predicting the axontal tracts arrangement in the blind regions of the images using the numerical modeling. To this end, a finite element model of the human...