Preparation and Physico-chemical Characterization of Titanium Dioxide Nanotubes with Electrochemical Method for Oxidative Dehydrogenation of Propane (ODHP)

, M.Sc. Thesis Sharif University of Technology Nik-khah, Maryam (Author) ; Kazemeini, mohammad (Supervisor)

Abstract

Samples of the V2O5 catalysts supported on nanostructures of TiO2 and γ-Al2O3 were synthesized via hydrothermal method for the oxidative dehydrogenation of propane (ODHP) to propylene. The TiO2 support was utilized in both commercial microstructures and prepared nanostructures from their corresponding salts. Furthermore,the γ-Al2O3 was also prepared from two novel methods. Moreover, the vanadium catalysts supported on hybrid TiO2 and γ-Al2O3 were prepared. The performances of the prepared catalysts were subsequently examined in a fixed-bed reactor. The main products were propylene, ethylene and COx.The vanadium catalyst over TiO2 and γ-Al2O3 had the best performance under the reactor test...

Theoretical study of CO adsorption on the illuminated TiO2 (0 0 1) surface

, Article Applied Surface Science ; Volume 256, Issue 12 , 2010 , Pages 3795-3798 ; 01694332 (ISSN) Bostandoust Nik, E ; Sadighi Bonabi, R ; Sharif University of Technology

2010

Abstract

A quantum modeling of the CO adsorption on illuminated anatase TiO2 (0 0 1) is presented. The calculated adsorption energy and geometries of illuminated case are compared with the ground state case. The calculations were achieved by using DFT formalism and the BH and HLYP. Upon photoexcitation, an electron-hole pair is generated. Comparing of natural population in the ground state and the exited state, shows that an electron is trapped in a Ti4+ ion and a hole is localized in an oxygen ion. The photoelectron helps generation of a CO2 molecule on the TiO2 surface. As shown by optimization of these systems, the CO molecule adsorbed vertically on the TiO2 (0 0 1) surface in the ground state...

Coordinated Scheduling of Power and Natural Gas Systems Considering Demand Uncertainty

, M.Sc. Thesis Sharif University of Technology Nik Payam, Hossein (Author) ; Rafiee, Majid (Supervisor)

Abstract

The everyday increasing electricity consumption of household and industrial sectors across the world, and also the limited generation capacity and fuel supplies has led electricity companies, whether in private or government sectors, to focus deliberately on power generation planning, its costs, risks and constraints Because of many reasons including high efficiency, low cost of capital investment, expeditious permitting, and operation flexibility of gas-fired generating units, electricity companies prefer them to old ones like coal-fired or oil-fired generating units. Thus natural gas has gained a significant share in the portfolio of electricity generation fuel resources, and it is...

Optimal Design of Tolerances in the Non-rigid Assemblies under the Thermal Impact

, M.Sc. Thesis Sharif University of Technology Hemati Nik, Javad (Author) ; Khodaygan, Saeed (Supervisor)

Abstract

Tolerance allocation in the recent mechanical assembly is significant because it straightly affects product performance and cost. Loose tolerances may cause the quality defect while tight tolerances can increase the cost. Thermal effects and the temperature gradients are one of the factors that caused changes in the size and geometry of the components during the performance of mechanical assemblies. This thesis proposes a new approach for tolerance design considering the thermal effects, to achieve lower manufacturing cost and good product quality. Finite element analysis is used to determine the deformation of components in an assembly. The neural network is trained using experimental...

Numerical Investigation of the Effect of Influential Geometrical Parameters on the Plugholing Phenomenon in Smoke Extraction

, M.Sc. Thesis Sharif University of Technology Zebardasti Nik, Ali (Author) ; Afshin, Hossein (Supervisor)

Abstract

Correct and timely extraction of smoke is very important in fire incidents. Statistics show that more than seventy percent of fire casualties are caused by breathing toxic gases. One of the destructive factors in the operation of the smoke exhaust system is the plugholing phenomenon. In this phenomenon, due to the improper design of the ventilation system, the exhaust vent extracts air instead of smoke. The plugholing phenomenon causes the accumulation of smoke in the structure, therefore it is essential to know this phenomenon to prevent it. In this research, the plugholing phenomenon in the smoke extraction process has been investigated by the numerical simulation method. To investigate...

Semi Supervised Approaches for Image Depth Estimation

, M.Sc. Thesis Sharif University of Technology Sanaei Nik, Arman (Author) ; Moghadasi, Reza (Supervisor)

Abstract

One of the important tasks in machine vision is 3D structure reconstruction or depth estimation. In recent decades, methods based on machine learning have been presented, which can be used to perform this costly task more optimally. For this purpose, two branches of supervised and unsupervised learning have been considered. In supervised learning, the available data is in the form of image-depth map pairs, such as the kitti dataset. The image is fed to the network and the output is made in the form of a depth map. The cost function of this network is obtained by comparing the generated depth map and the depth map in the data set calculated by laser. In unsupervised learning, there is no...

Ultrasonic-assisted grinding of Ti6Al4V alloy

, Article Procedia CIRP ; Volume 1, Issue 1 , 2012 , Pages 353-358 ; 22128271 (ISSN) Nik, M. G ; Movahhedy, M. R ; Akbari, J ; Sharif University of Technology

2012

Abstract

In conventional grinding of hard to cut materials such as Ti6Al4V alloys, surface burning, redeposition and adhesion of chips to the grinding wheel and workpeice occur visibly unless it is carried out at low speeds and with high volume of cutting fluid. Ultrasonic assisted grinding is an efficient machining process which improves the machinability of hard-to-cut materials by changing the kinematics of the process. In this research, the effect of imposition of ultrasonic vibration on the grinding of Ti6Al4V alloy is studied. Longitudinal vibration at ultrasonic frequency range (20 kHz) is applied on the workpiece and machining forces and surface roughness are compared between conventional...

Effect of Soil-Structure Interaction on Practical Design of Ordinary Buildings Based on Iranian Seismic Code

, M.Sc. Thesis Sharif University of Technology Rezaei Nik, Danial (Author) ; Ghannad, Mohammad Ali (Supervisor)

Abstract

In the last few decades Seismic Regulations attitude’s has been undergone significant changes from various aspects. One of these aspects is entering new topics based on the latest scientific achievements. Soil-Structure Interaction terms was from such issues which had found their ways into Seismic codes as an optional effective factor. In recent years, Based on this new attitude and Scientific achievements, Soil-Structure Interaction terms entrance into Iranian seismic code (2800 Standard), is also has been studied. Naturally, applying these criteria will impact on the design and performance of structures, because of reducing effect of soil structure interaction on decreasing base shear...

Decision Matrix for Time-Critical Optimal Trajectories for Air-Launch of Small Satellites

, M.Sc. Thesis Sharif University of Technology Farzam Nik, Ehsan (Author) ; Malaek, Mohammad Bagher (Supervisor)

Abstract

One of the satellite time-critical launch methods is air-launch, which is considered in this research thoroughly. The Large number of important parameters of this method makes the system highly complex. In such complex systems, usual methods of design and development will not be effective. Moreover, based on systemic approaches, interfaces between different elements of a complex system have significant effects on the performance of the whole system. One of the methods for analysis of such systems is “Design Structure Matrix” or DSM. This method is based on system engineering principles and has confirmed capabilities in analysis of highly coupled systems.
In this research, the air launch...

Identification of Self-Leadership Strategies of Social Entrepreneurs in Face of Challenges of their Career

, M.Sc. Thesis Sharif University of Technology Nik, Farzaneh (Author) ; Alavi, Babak (Supervisor) ; Tasavori, Misagh (Supervisor)

Abstract

The present study seeks to focus on social entrepreneurs to address how these entrepreneurs continue to have sufficient motivation to overcome the challenges they face in the course of their careers and continue this path. This research has tried to use the concept of self-leadership - which keeps a person motivated to achieve his goals for which he has an inner motivation - to answer this question. So the main research question is how do social entrepreneurs use their leadership in the face of the challenges of their careers? To answer this question, this study used a qualitative research method with an exploratory approach and conducted semi-structured interviews with 14 social...

Evaluation of the optimal performance of passenger vehicle by integrated energy-environment-economic modeling

, Article International Journal of Environmental Science and Technology ; Volume 4, Issue 2 , 2007 , Pages 189-196 ; 17351472 (ISSN) Farzaneh, H ; Saboohi, Y ; Sharif University of Technology

CEERS 2007

Abstract

Analysis of multi dimensional interactions of flow of energy in passenger vehicle is a complex task that necessitates development and utilization of analytical tools. Development of analytical tools with high complexity is usually based on conclusions of many concepts and theories from different scientific disciplines. In this approach, Passenger vehicle is supposed to be organized in the form of a firm and appears in the market that oriented towards establishing an effective energy supply system which may be identified as delivering the product (person kilometer or tone kilometer) with minimum operation costs. To this end, an optimization model named power software founded on theory of firm...

Model for analysis of energy flow from tank-to-wheel in a passenger vehicle

, Article 2005 IEEE Vehicle Power and Propulsion Conference, VPPC, Chicago, IL, 7 September 2005 through 9 September 2005 ; Volume 2005 , 2005 , Pages 150-153 ; 0780392809 (ISBN); 9780780392809 (ISBN) Farzaneh, H ; Saboohi, Y ; Sharif University of Technology

2005

Abstract

Analysis of multi dimensional interactions of flow of energy in passenger vehicle is a complex task that necessitates development and utilization of analytical tools. Development of analytical tools with high complexity is usually based on conclusions of many concepts and theories from different scientific disciplines. In this approach, Passenger vehicle is supposed to be organized in the form of a firm and appears in the market that oriented towards establishing an effective energy supply system which may be identified as delivering the product (person per mileage removable) with minimum operation costs. To this end, an optimization model named POWER software founded on theory of firm of...

Software of passenger vehicle optimal work and energy recovery (POWER)

, Article 12th International Conference on Urban Transport and the Environment in the 21st Century, URBAN TRANSPORT 2006, UT06, Prague, 12 July 2006 through 14 July 2006 ; Volume 89 , 2006 , Pages 691-699 ; 17433509 (ISSN); 1845641795 (ISBN); 9781845641795 (ISBN) Farzaneh, H ; Saboohi, Y ; Sharif University of Technology

2006

Abstract

In our investigation, the model of optimal energy flow in a passenger vehicle has been founded on the theory of firm microeconomics. Based on this theory, the car owner tries to minimize the total cost of the system (including the cost of time of the traveller) subject to the satisfaction of the required transport services and technological, economical, environmental and institutional constraints. The aforementioned model has been developed using a technique of mathematical programming. The model depicts the behaviour of a nonlinear system and it includes many nonlinear functions in the objective function and in the constraints. Solving the large nonlinear set of constraints and identifying...

Radiowave Propagation Modeling Along a Street for Use in Microcells in Third Generation Wireless Communications

, M.Sc. Thesis Sharif University of Technology Sadeghi, Hamed (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

In this thesis, a simplified method was introduced to model the wave scattering by the metallic objects in a microcell, in order to determine the coverage pattern. First, the equivalent images method was introduced, which models the building walls effect. This method is fast, memory saving and accurate enough to estimate the scattered fields. Two-ray incidence model accuracy was investigated and confirmed in modeling the scattering from the metallic objects. This method also enhances saving in time and memory. The accuracy of single scattering assumption was investigated and confirmed in a scenario of multiple metallic scatterers. Based on this assumption, we can superimpose the scattered...

Design and Simulation of Smart Patch Antenna Array in 2.4 GHz band

, M.Sc. Thesis Sharif University of Technology Hosseini, Mahdi (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

Over the past few years , demand for wireless communication services have grown at a formidable rate. As such we need to find new ways to support more and more wireless users in a confined space. this means that the capacity of networks should be significantly increased to overcome formidable rate of subscribers growth. That is why the smart antennas have become very popular in communication systems. Smart antennas are a kind of adaptive antenna arrays with smart signal processing algorithms used to find direction of arrival(DOA) of the signal, and use it to calculate suitable weights to direct the antenna beam on the desired user and nulling interferences. In this thesis, DOA estimation...

Evaluation of Phase Comparison DOA Estimation Methods in Multipath Environments for Millimeter Waves

, M.Sc. Thesis Sharif University of Technology Karimi, Parisa (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

The main objective of this project is to discuss a DOA estimation system performance in a multipath environment. For this goal, first the basics of the DOA Estimation systems are discussed. Evaluation of different types of algorithms and choosing an appropriate one is an important step in this regard. Moreover the comparison of different array structures is necessary to choose the appropriate one. The major part of the project has been dedicated to discussion of multipath phenomenon as a major source of error in DOA estimation and studying the multipath mitigation algorithms to eliminate the aforementioned error. A model based on the concept of Bistatic Radar Cross Section is proposed to...

Evaluation and Improvement of DOA Estimation Methods in Dipole Antenna Arrays with Different Geometries

, M.Sc. Thesis Sharif University of Technology Sasannia, Zahra (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

In this thesis, some of the well-known DOA algorithms namely Bartlett, Capon, Linear prediction, Maximum Entropy, Pisarenko harmonic decomposition, Minimum norm and MUSIC are analyzed and compared with each other in the identical situations using a uniform linear array. Then based on these comparisons, the appropriate algorithm is selected. In the next step since the linear arrays can't estimate both angles of arrival (Azimuth and Elevation) simultaneously, two dimensional (2D) geometries are introduced and are also compared to each other. Then one of them (circular array) is selected for dipole antenna arrays. The performance of the selected array is evaluated using isotropic elements for...

Analysis and Simulation of Mars Rover Curiosity in the X and UHF Bands

, M.Sc. Thesis Sharif University of Technology Torabi, Masoud (Author) ; Forouhar, Farzaneh (Supervisor)

Abstract

Mars rover Curiosity is a mobile scientific laboratory which it’s mission is to assess the biological potential of the landing site and characterize the geology of the landing region. This rover communicate to a Mars orbiter named MRO satellite in the UHF band which relies the signals to the Earth stations. Also this rover communicate to the Earth stations directly in the X band. In this thesis, we determine the technical characteristics of stations and simulate Earth-Mars radio links. So we calculate :
1. determine the technical characteristics of Earth stations
2. determine the technical characteristics of satellite and Curiosity
3. Earth-Mars orbital position in the...

, M.Sc. Thesis Sharif University of Technology Razieh, Azad (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

In recent years due to the advances in semiconductor technology and the ability to implement small-scale manufacturing, communication at 60 GHz band receive more attention than ever has been. The use of this frequency band is not only about 7-9 GHz unlicensed broadband access provided, but getting smaller devices make it possible to use multiple antennas at the transmitter and receiver, and thus taking advantage of multiple input – multiple output systems. Antennas used in these systems should have features such as small size , low weight, high gain and bandwidth and also they should keep their high efficiency and gainat high frequency range (about a few GHz ). To achieve these features...

Switched Parasitic Antennas for the use in Wireless Communications

, M.Sc. Thesis Sharif University of Technology Ahmady, Hesam (Author) ; Farzaneh, Forouhar (Supervisor)

Abstract

Switched Parasitic Antennas, as a kind of Smart Antennas, have several applications in Telecommunications and Radar systems. In the realm of wireless applications, these antennas provide the system with higher capacity owning to the fact that they are able to direct the main beam toward the desirable user. Moreover, they can be used to degrade the adverse effects of Multi-path. Multi-path reduction not only benefits mobile communication but applies to many applications of radar systems. These antennas, in addition, can be utilized in Direction Finding. In the case of other types of Smart Antennas, the above mentioned benefits can be achieved with high costs due to the fact that there are a...