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sensitivity-analysis
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Total 517 records
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
As petroleum resources are not steadily distributed in the world and all industries and manufacturing sections are dependent on these resources, petroleum transportation is very important to the extent that availability of these resources occurs in the fastest time and costing the least possible. The objective of this study is to study the petroleum distribution through time in the world and assess its transportation efficacy during 1965-2005 in 173 countries. Collecting information about petroleum distribution between exporting countries to importing ones helped to complete the study data base. Also in this study two transportation networks, sea and land multimodal transportation network...
Experimental and Simulation Study of Asphaltene Deposition in Porous Media
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, sirous (Supervisor) ; Kharrat, Reyaz (Supervisor)
Abstract
Asphaltene deposition on reservoir rocks occurs during natural depletion as well as miscible injection processes. It causes reduction of effective pore space and consequent impairment of the ability of oil to flow through reservoir. Therefore, deposition of asphaltene causes significant formation damage and wellbore plugging, requiring expensive and difficult cleanup procedures. Thus it is necessary to be able to consider the onset, amount of deposition and also consequent damage of permeability and porosity reduction due to various factors. The objective of current work is to conduct experimental and simulation study of asphaltene deposition dynamics in one of the Iranian reservoirs. In...
A Review on DEA and Development of an Algorithm on Sensitivity Analysis and Stability Region
, M.Sc. Thesis Sharif University of Technology ; Modarres Yazdi, Mohammad (Supervisor)
Abstract
Data envelopment Analysis is a non parametric technique which estimates the efficiency of a decision making unit in compare with others. In correspondent literature this unit’s Inputs and outputs are often assumed to be deterministic, but in recent years different approaches which viewing the data as non deterministic are presented. In this study we propose an algorithm for determining the stability region of a DMU while we assume other DMUs’ data are fixed. This algorithm is based on changing the reference set of the under investigation DMU. In fact applying these changes make the DMU move toward other DMUs’ efficient frontiers and by using this fact it is possible to determine the...
Optimization and Control of DME Plant Based on Fuzzy Optimization
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehry Boozarjomehry, Ramin (Supervisor)
Abstract
In recent years, due to the energy price increase, great efforts were made to optimize the operating conditions of various chemical processes in order to reduce the operating cost and obtain the maximum possible profit. Decision makers should usually deal with different kinds of uncertainty in process optimization. In this situation, fuzzy optimization is an ideal method, since it represents and handles the underlying uncertainty of the optimization problems. In this paper, the optimization problem for production process of dimethyl ether (DME) as an alternative fuel to diesel is considered. Both crisp and fuzzy approaches are applied to formulate the optimization problem while sensitivity...
Technical and Economical Feasibility Study of Using Flare Gas for Converting to Other Products in Iran
, M.Sc. Thesis Sharif University of Technology ; Sattari, Sourena (Supervisor)
Abstract
The Increasing trend of gas flaring over oil fields and gas process systems in Iran not only causes several environmental problems, but makes the economical resources useless as well. Considering the high amount of flaring and old facilities, one of the best solutions is the recovery of the flare gas in Iran. It seems that collecting the flare gas is not possible in different sectors. Therefore, using a plant for converting flare gas to other products must be logical. In this project, the feasibility study of converting flare gas to other products is studied. For this reason, a methanol plant is simulated; whose input feed is the content of flare gas of the South of Iran (Marun and Siri)....
Numerical Study of Ground Vibrations due to Pile Driving and Effect of Trench on Reduction of Amplitude of Vibrations
, M.Sc. Thesis Sharif University of Technology ; Ahmadi, Mohammad Mehdi (Supervisor)
Abstract
Ground vibration during pile driving is one the most important factors that limits usage of this kind of piles. It is of great importance to estimate the level of vibration prior to the beginning of pile driving to avoid structural damage or disturbance of building occupants. In this study, an axisymmetric finite element model that utilises an adaptive meshing algorithm has been introduced, using the commercial code ABAQUS, to simulate the full penetration of a pile from the ground surface to the desired depth by applying successive hammer impacts. The model has been verified by comparing the computed particles velocity with those measured in the field. The results indicate that the peak...
Sensitivity Analysis of Piezoelectrical Actuator Microgripper
, M.Sc. Thesis Sharif University of Technology ; Ramezani, Asghar (Supervisor) ; Ghaemi Osgouie, Kambiz (Supervisor)
Abstract
Increasing and diversified use of micro electromechanical components necessitates further development of methods for their secure gripping and transfer. In this research, a piezoelectrically driven microgripper including two gripping sets with four arms has been designed. The system can hold and handle microparts from 100 to 150 microns by applying corresponding voltages between 80 to 20 volts. The design is such that after positioning the work piece between the two microgripper arms the piezoelectric comb-drive actuators are activated. Then the two gripping arms are moved toward each other and ultimately grasp the work piece. In order to determine the behavior of the...
Dynamic Simulation of Molten Carbonate Fuel Cell
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
In this work, a model was presented for an MCFC fuel cell with internal reforming and combustion chamber. The model consists of mass and heat transfer equations beside the chemical and electrochemical reaction rate equations. Velocity distribution due to reactions and temperature distribution along the cell is considered. The model has been simulated in steady state form using finite difference method in MATLAB package environment accompanied by the analysis of the dynamic behavior of cell using method of lines in Simulink environment. Simulation results have been validated with experimental data extracted from literature. The last part of the work concerns with sensitivity analysis of some...
Sensitivity Analysis in Total Search Domain and Automatic Selection of the Most Sensitive Matching Parameters in Tuning of EOS and History Matching
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
One of the major issues raised in the numerical models is the effects of various input parameters on the model output. Identifying the most important parameters in the output is very important in petroleum engineering, especially in tuning equation of states and history matching. Screening the most important parameters from unimportant parameters is assessable by sensitivity analysis.In this study local and global sensitivity analysis methods are used to identify the most important parameters in tuning EOS for seven different fluid samples. Global sensitivity analysis methods are more successful in correct ranking of tuning parameters. Morris method as a global method can screen the...
A 35 Step Reduced Mechanism for Methane-Air Combustion to Estimate Pollutants
, M.Sc. Thesis Sharif University of Technology ; Mazaheri, Karim (Supervisor)
Abstract
A novel reduced mechanism is introduced which aimed to predicts NOx and CO generation in advanced industrial gas turbine combustors. The survey is initially conducted by considering 25 species in GRI-3 mechanism of Methane oxidation and continued to choose nine of the most important species based on the quasi-steady state analysis. Finally, a new skeletal reduced mechanism with 35 reactions and 20 species is derived using sensitivity analysis, reaction path analysis, and some physical reasons. The overall validity of this mechanism is clearly confirmed by comparing the present predicted results with GRI-3 full mechanism in a PSR reactor. The adiabatic flame temperature and all of the main...
Assessment of Caspian Gas Transit and its Effects on the Interests of the Iranian Desired
, M.Sc. Thesis Sharif University of Technology ; Maleki, Abbas (Supervisor)
Abstract
In this project a model for the analysis and assessment of gas transit in the Caspian Sea and its effects on the desired benefits of the approach of decision-making, has been developed.
The first comprehensive review of the supply and demand of gas in the world and the countries of the Caspian region and the cast has been affecting world energy developments.After a comprehensive analysis of the status of the gas transit routes from the Caspian region and provided. Then, using the Delphi method and elite views the main criteria related to gas transit and affecting the interests of the countries of the Caspian region to determine the detailed criteria for each main criterion was determined...
The first comprehensive review of the supply and demand of gas in the world and the countries of the Caspian region and the cast has been affecting world energy developments.After a comprehensive analysis of the status of the gas transit routes from the Caspian region and provided. Then, using the Delphi method and elite views the main criteria related to gas transit and affecting the interests of the countries of the Caspian region to determine the detailed criteria for each main criterion was determined...
Feasibility Study for Establishment of a Casing Pipe Threading Plant in IRAN Oil Industry Via UNIDO Approach
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
Regarding high importance of casing pipes in oil industry also considering that they have not been producing domestically (with specific features), the main object of this research is feasibility study of establishment of a casing pipe threading plant which produces such kind of pipes. Usage of Casing PipesIs defining as a separator between wall of oil well and its core. The operation starts with driving and fixing a casing pipe to the oil well to avoid its collapsing during excavation process , then next casing pipes will be driven to the well and will be fixed to the previous pipes. During current research, after gathering all related financial and technical data, evaluation of “Net...
Ekranoplan Design Survey, Determination and Enhancement of Flying Qualities characteristics Through Stability Alalysis
, M.Sc. Thesis Sharif University of Technology ; Banazadeh, Afshin (Supervisor)
Abstract
During the last five decades, interest in High Speed Marine Vehicleshas been increasing for both commercial and military use, leading to newconfgurations and further development of already existing configurations to fill the gap between the low speed ships by high payload capacity to low construction cost, and high speed aircrafts by low payload capacity to high construction cost. Therfore Wing-In-Ground effect crafts (WIG)were introduced as the new marine vehicles family memberwhich have the potential for payload capacities closer to fast marine crafts and the cost of construction is much lower than aircraftswhile they are capablefly close to the water surface. On the whole, in this...
Uncertainty Analysis and Inverse Modeling of Seawater Intrusion in Coastal Aquifers
, Ph.D. Dissertation Sharif University of Technology ; Ataei Ashtiani, Behzad (Supervisor)
Abstract
Groundwater is the primary source of freshwater in many coastal areas and small islands around the world. The most important hazard to groundwater quality in coastal aquifers is seawater intrusion (SWI) resulting from over pumping, prolonged drought conditions and sea level rise due to climate change impacts. Numerical models of SWI are an important tool in the management of coastal aquifers. However, numerical modeling of SWI is one of the most challenging problems in groundwater hydrology. One of the reasons for the challenging nature of SWI numerical modeling is the relatively large level of uncertainty associated with the estimation of the model input parameters. This study focused on...
Seismic Reliability and Global Sensitivity Analysis of Concrete Gravity Dams
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor) ; Toufigh, Vahab (Supervisor)
Abstract
This research investigated the seismic performance of gravity dam in the reliability and sensitivity analysis framework under earthquake loading. The performance criteria were defined using crest displacement and tensile stress. The uncertainty due to the material properties of the dam was considered for the reliability approach, in addition to the different ground motion intensity levels for parametric analysis. The exceedance probability of the limit-state functions was computed for varying threshold values through Mean-Value Second-Moment, First-Order Reliability Method and improved Latin Hypercube sampling. Approximation methods were applied along with the sampling method for considering...
A Study of Trade and Transportation Trends in Asia
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
Considering the extensive developments achieved up to now in the fields of trade and international transportation, as well as the key role of the freight transportation in the economical development of a zone or a country, the present research, titled “A Study of the Trade and Transportation Trends”, was planned. The available data concerning the trade of six types of the goods according to The United Nations Classification (SITC), within the period 1965-2005, have been analyzed in this research. The study has been focused on the Asian Multimodal Network constituted of 31 countries. Trading centre of each country in the selected network is assumed to be located in its capital town. The...
Modeling and Simulating of Water Distribution in Different Layers of Direct Methanol Fuel Cell
, M.Sc. Thesis Sharif University of Technology ; Baghalha, Morteza (Supervisor)
Abstract
A two-dimensional, two-phase, nonisothermal model was developed in this work to investigate the water transport characteristic and water distribution in a direct methanol fuel cell (DMFC). Emphasis is placed on exploring the water distribution in different layers of DMF. The water and methanol crossover through the membrane were considered with the effect of diffusion, electro-osmotic drag, and convection. Governing equations including the prton and electron transport, continuity, momentum, species transport for methanol, water, and gases species, and the auxiliary equations are coupled to determine the output parameters. These parameters are the concentration distribution of the species,...
Modeling and Sensitivity Analysis of Heavy Vehicles Tire With Target of Determining Stiffness and Damping Characteristics
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmoud (Supervisor) ; Fallah Rajabzadeh, Famida (Supervisor)
Abstract
Tire is one component of the suspension system and has beneficial effects on reducing vibrations caused to the vehicle. This study aims to determine the factors affecting the damping and stiffness of the tire is carried out. The modeling of factors were identified. For testing the modeling effort is to be made to the instruments used to measure the damping and stiffness of the tires. To make the structural static analysis, dynamic and modal was to have sufficient structural strength and the displacements and stresses are sensibly placed. Factors that have influence on the hardness of the ring diameter, the outer diameter of the tire, tire pressure, tire tread depth, tire wall thickness,...
Optimal Design of Functionally Graded Materials Under Thermomechanical Loadings
, M.Sc. Thesis Sharif University of Technology ; Tavakoli, Rohollah (Supervisor)
Abstract
A numerical algorithm for the optimal design of two components functionally graded materials under thermomechanical loadings is introduced in the present study. It is based on the topology optimization method. The objective function, to be minimized, is defined as the weighted combination of the thermal and mechanical compliance of structure. The design variables are defined as the local volume fractions of contributing phases. The set of constraints includes bound constraints on local volume fractions and a global constraint on the total volume fraction of the matrix phase. The corresponding heat and elasticity equations are solved by the finite element method. The local material properties...
An Investigation on the Resonant, Frequency and Nonlinear Behavior of Atomic Force Microscope (AFM) Modeled on the Basis of the Nonlocal Theory
, M.Sc. Thesis Sharif University of Technology ; Ahmadian, Mohammad Taghi (Supervisor) ; Mehdigholi, Hamid (Supervisor)
Abstract
Atomic force microscope (AFM) has a significant capability of imaging surface topography on an atomic scale. It is also widely used for Nanolithography in MEMS/NEMS (micro/nanoelectromechanical systems). Although the conventional AFMs have a significant capability of nano-scale surface measurements, their probe tips cannot come in close proximity to the sidewalls, no matter how sharp they are. Therefore, no accurate nano-scale measurements at sidewalls and edges can be achieved by these conventional AFMs. In addition, regarding the increasing applications of micro-structures such as micro nozzles, micro gears, micro holes and micro trenches which all of them have sidewalls and edges,...