Loading...
Search for:
sensitivity
0.019 seconds
Total 1087 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...
Analytical and Experimental Study of Isolation of Sensitive Equipments from Ambient Vibrations
, M.Sc. Thesis Sharif University of Technology ; Bakhshi, Ali (Supervisor)
Abstract
In some activities, an almost free of any vibration environment is needed. Semi conductor production process and microelectronic microscopes are two examples in which a quiet environment is essential. The goal of this thesis is to attenuate ambient vibrations effectively and to prepare a suitable environment for two microelectronic microscopes. The designed system must be practical, economical and capable of being made in a short time interval. Considering mentioned properties a steel table with bolt connections supported on 4 air springs was built. To investigate dynamic properties, modal analysis was performed with the aid of finite element packages and experiments. To extract oscillations...
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...
Integrated Pricing and Queuing Problem
, M.Sc. Thesis Sharif University of Technology ; Shavandi, Hasan (Supervisor)
Abstract
Joint price and service capacity decisions and integrated pricing and queuing problems with finite or infinite buffers are two remarkable issues of pricing research. In this thesis we consider a joint price and service capacity determination problem in a single server, finite buffer queuing system. Customers arrival and serving occur as Poisson processes. Because of finite buffer capacity, customers finding the system full upon their arrival would be rejected. Customers differ with respect to their reservation prices and time sensitivities. This study focuses on investigating the effect of finite buffer capacity and customers reservation prices and time sensitivities on optimal policy and...
Electrophoretic Deposition of Titanium Dioxide for Fabrication of Photoanode of Dye Sensitized Solar Cell
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
This research is focused on fabrication of TiO2 layers by electrophoretic deposition (EPD) for application as photoanode in Dye Sensitized Solar Cell (DSC). DSCs are third generation of solar cells, also known as the Grätzel cell, after its inventor Michael Grätzel. A DSC is composed of a porous layer of wide band gap semiconductor such as TiO2 and ZnO, covered with a molecular dye that absorbs sunlight, and a counter electrode contacted by a liquid redox electrolyte. Dye Sensitized semiconductor (photoanode) has important role in conversion of photon to electricity. To achieve higher efficiency, preparation of photoanode with high surface area resulted to enough dye adsorption is necessary....
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...
Fabrication of Dye-Sensitized Solar Cells Based on TiO2-ZnO Double Layer Nanostructured Film
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
In the present work, one dimensional ZnO nanostructures were grown by seed-assisted hydrothermal method. Hydrothermal processing parameters were controlled to obtain ZnO nanorods with diameter lower than 120 nm. The products were characterized by FE-SEM, EDAX, XRD, PL, and ATR-FTIR analyses. ZnO nanoparticles were also synthesized via a simple solvothermal method and their photo peropeties were compared with onedimensional nanostructures. Thereafter dye-sensitized solar cells based on TiO2-ZnO double layer nanostructured film were fabricated. It was observed that DSSC efficiency increased with decreasing the thickness of the film. The highest efficiency of 2.41% was obtained
Flight Dynamic Modeling of an Articulated FMAV Using Quasi Steady Aerodynamics
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
This thesis is focused on flight dynamics modeling and analysis of an articulated Flapping Micro Air Vehicle (FMAV), where the articulating joint is placed near the wing mid chord span. The articulation modeling, its results and verification due to added degrees of freedom are considered the key motivation and novelties of this project. Initial analyses indicated that a simple articulation device such as joint is not appropriate and will not be efficient for flying FMAV. As a corrective action, a spring-damper mechanism was utilized beside the articulation. Subsequently, the kinematics’ equations are developed and verified using the MSC Automated Dynamic Analysis of Mechanical Systems...
Synthesis of Titania Hollow Spheres in Dye Sensitized Solar Cell Application
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
In the current research, Anatase-Rutile Titania hollow spheres were synthesized using hydrothermally prepared carbon spheres as template. Different calcination temperatures were used to remove carbon template and crysalized Titania. The characterizations for the physicochemical properties of prepared samples were carried out by XRD, FESEM, XPS, DRS, UV-Vis and FTIR.It is found that doping of carbon in the crystal structure of Titania hollow sphere, cause red shift in band gap wavelenght and the absorption wavelength edge was expanded to the visible light region and the additional diffusive electronic states were observed on the valence band spectra of samples.The photoelectric conversion...
Fabrication of TiO2 Dye-sensitized Solar Cells with Different Morphologies and Phase Compositions of Scattering Layer
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Different types of morphologies and phase structures of crystalline TiO2 were synthesized by hydrothermal methods. For the first time, dandelion-like rutile TiO2 powder composed of numerous single crystalline nanorods was synthesized using TiCl4 as the main precursor. TiO2 Nanoparticles were produced using TTIP and 2-propanol, as precursor and solvent, respectively. Field emission scanning electron microscopy analyses revealed that the synthesized TiO2 nanoparticles had average crystallite size in the range 21–70 nm, whereas dandelion-like TiO2 showed diameter in the range 2-10 µm. According to the significant refractive index of TiO2, in particular rutile phase, it can be used in the...
Integrated Supply Chain Network Design in Time-Sensitive Products
, M.Sc. Thesis Sharif University of Technology ; Akbari Jokar, Mohammad Reza (Supervisor)
Abstract
Logistics includes the flow of goods, information and other sources between production and consumption node to meet the demand of customers. Basically, Logistics includes the integration of information, transportation and inventory. This study is in association with how to phase-out the old product when the new one is developed, and also is about how to manage the remaining inventory in a phase-out period focusing on such decisions as time and discount amount. Often in retailing system, old products have been phased out with an introduction of a new one by distributors. In order to sell this amount of products in a specific time period retailers need to create a mechanisim to phase-out the...
Determining Location and Estimating Severity of Damage Using Sensitivities of Principal Components of Frequency Response Functions
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofouei, Fayyaz (Supervisor) ; Esfandiari, Akbar (Supervisor)
Abstract
Principal component analysis (PCA) is a conventional tool for dynamic system analysis. In this paper, a new damage diagnosis method is presented based on sensitivities of principal components obtained from PCA of Frequency response functions (FRFs). Damage identification, determination of its location and estimation of the damage severity are conducted by an innovative well established sensitivity relation of PCA results. Then, sensitivity matrix is obtained by using measured frequency of damaged structure, and comparison of PCA of the intact structure with PCA from FRFs which are measured at sensors locations. Damage location and its severity are calculated by model updating procedure. This...
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...