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Autonomous runway alignment of fixed-wing unmanned aerial vehicles in landing phase
, Article 5th International Conference on Autonomic and Autonomous Systems, ICAS 2009, Valencia, 20 April 2009 through 25 April 2009 ; 2009 , Pages 208-213 ; 9780769535845 (ISBN) ; Saghafi, F ; Sharif University of Technology
2009
Abstract
In this paper, the development of a controller for autonomous lateral alignment of fixed-wing Unmanned Aerial Vehicles (UAVs) with runway centerline in landing phase is presented. Fuzzy Logic Control (FLC) is used in order to enable the vehicle to mimic the decision making procedure that a pilot follow in the same situation. Also, for longitudinal motion controller design for the UAV to follow a pre-defined trajectory, the pole-placement technique is used. It is assumed that the runway relative position and orientation are provided by a built in vision system and its associated image processing unit. The performance of the controller in the presence of the Gaussian noises is investigated by...
Improved optimal control technique for control of parallel three- phase inverters
, Article 2009 International Conference on Electric Power and Energy Conversion Systems, EPECS 2009, Sharjah, 10 November 2009 through 12 November 2009 ; 2009 ; 9789948427155 (ISBN) ; Mokhtari, H ; Sharif University of Technology
2009
Abstract
This paper proposes a high performance voltage tracking and current sharing among parallel connected inverters by applying optimal control and minimizing the cost function. The control system forces the voltage of load to track the voltage reference, and the current of all inverters becomes equal. Therefore, both current sharing and voltage tracking are obtained. In addition, the smallest input energy and simplicity in control circuit are the other advantages of the suggested method. To show the performance of the proposed control scheme, the simulations with two-modular practical systems are performed and the results are provided. The results indicate that the control objectives are...
Seismic Response of “Karroon III” DAM to Non-Uniform Ground Motions
, M.Sc. Thesis Sharif University of Technology ; Ghaemian, Mohsen (Supervisor)
Abstract
Usually in analysis of arch dams, applied seismic motions on dam-foundation interface are assumed to be uniform. This is while that recorded motions show non-uniform accelerations in dam-foundation interface. Analyzing of the dam under this non-uniform accelerations we can find the importance of this assumption in analysis of arch dams. Two earthquakes were excited “KAROON III” dam at 20.11.2007 and 21.11.2007. The respective motions were recorded by the array of accelerometers that has been installed on the dam. The recorded motions, indicated non-uniformity of excitations in accelerometers were installed near the dam-foundation interface. Therefore this data provided an opportunity to...
The effect of non-uniformity in ground motions on the seismic response of arch dams
, Article SN Applied Sciences ; Volume 3, Issue 3 , 2021 ; 25233971 (ISSN) ; Sohrabi Gilani, M ; Ghaemian, M ; Sharif University of Technology
Springer Nature
2021
Abstract
Recorded ground accelerations at various locations of Karun III Dam during November 20, 2007, were recorded by an array of accelerometers located on the dam. In terms of amplitude and phase, these accelerations show non-uniformities in different elevations. In this paper, the effect of these non-uniform ground motions on the seismic response of the dam taking dam-reservoir-foundation interaction into account is investigated. The EACD-3D-2008 finite element program and ABAQUS Software are used for carrying out the seismic analyses. For this purpose, time histories of the earthquake accelerations are interpolated at nodal points located on the dam foundation interface. The analysis has been...
Thermal analysis of RCC dams during construction considering different ambient boundary conditions at the upstream and downstream faces
, Article Journal of Civil Structural Health Monitoring ; Volume 12, Issue 3 , 2022 , Pages 487-500 ; 21905452 (ISSN) ; Sohrabi Gilani, M ; Ghaemian, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Thermal analysis of Roller Compacted Concrete (RCC) dams is generally carried out considering identical ambient boundary conditions at upstream and downstream faces. For the case of Shahri-Kor Dam (an RCC dam with a height of 57 m), recorded thermal data depicts a considerable difference between upstream and downstream ambient temperatures, especially during cold months. This paper investigates how taking this difference into account can affect the thermal response of the dam. For this purpose, two thermal analyses are carried out with and without consideration of these different ambient boundary conditions (DABC). Consequently, the computed temperatures at representative points are compared...
Design of a Control System Based on the Permanent Magnet for Control of a Magnetic Catheter
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Currently, the use of robots and microrobots in medical applications has significantly increased due to their extensive and unique capabilities. One such application involves the utilization of magnetic continuum robots controlled by an external magnetic field in minimally invasive surgeries. This research focuses on discussing methods for effectively controlling magnetic-continuum robots and applying external magnetic fields. Two primary methods for applying the external magnetic field are explored: the use of electromagnetic coils and permanent magnets. Based on these methods, systems for applying the field and controlling the magnetic continuum robot have been constructed and...
Fermionic Approach To The One Dimensional Kondo Necklace Model
, M.Sc. Thesis Sharif University of Technology ; Langari, Abdollah (Supervisor)
Abstract
Strongly correlated materials are kind of materials in which novel electric and magnetic properties will appear as a result of strong correlations among their electrons like “heavy fermion materials”. Kondo lattice model is a model to describe heavy fermion materials. If we are merely interested in the magnetic properties of heavy fermions we can replace the Kondo lattice Model with the simpler model called the Kondo-necklace model which consists of the interactions only among the spins of the itinerant (conduction) and localized electrons (magnetic impurities) and also the interactions between the spins of the itinerant electrons. In this thesis we investigate the properties of the one...
Experimental Study of Oxygen Reduction Reaction (ORR) on Cu-alloys, Electrocatalysts in Alkaline Solution and Theoretical Investigation of Oxygen Adsorption on Cu-alloys Nano-clusters
, Ph.D. Dissertation Sharif University of Technology ; Gobal, Fereydoon (Supervisor)
Abstract
In this study, electrochemical oxygen reduction reaction (ORR) was studied on Cu, Pd, Rh, Pd-Cu and Rh-Cu alloys in alkaline solution. Pd-Cu and Rh-Cu alloys were prepared by electrochemical methods. On copper electrode it is found that direct oxygen reduction is accompanied by the electrochemical reductions of copper oxides. Also, mechanism and kinetics of reaction change as the amount of copper oxides increase on the surface. For electrodeposited alloys, it is indicated that the reactivity of Pd-Cu and Rh-Cu alloys toward oxygen reduction is higher than pure Pd and pure Rh. The maximum reactivity among Pd-Cu alloys is related to the sample with 24.5% copper content while the maximum...
Cavity Quantum Electro-Dynamics in Ultra-Strong Coupling Regime
,
M.Sc. Thesis
Sharif University of Technology
;
Khorasani, Sina
(Supervisor)
Abstract
Cavity Quantum Electro-Dynamics (CQED) in Weak, Strong and Ultra-Strong coupling Regimes are studied. A MATLAB m-file is written which is able to solve any arbitrary CQED configuration. This program demands input data such as number of Quantum Dots, number of energy levels of each Quantum Dot, energies of each energy level of Quantum Dots, Number of cavity modes, eign-frequency of each cavity mode, coupling constant, dipole strength of each allowed transition of Quantum Dots and initial state of system from user and begins to solve the Schrodinger equation for annihilation and atomic ladder operators. In addition, coefficients of each possible ket will be calculated. Since, any approximation...
Synthesis and Characterization of Bis[2-(2׳-Hydroxyphenyl)- -oxazolinato]Ni(II) Complex and Investigation of it׳s Catalytic Activity in C-C Coupling Heck Reaction
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this study a new Ni(II)-¬oxazoline complex was synthesized by reaction of Ni(CH3COO)2.4H2O and 2-(2׳-hydroxyphenyl)-2-oxazoline ligand in MeOH solvent. The resulting complex bis[2-(2׳-hydroxyphenyl)-2-oxazolinato]Ni(II), was characterized by different spectroscopic methods. X-ray diffraction showed that this complex is four coordinated with a square planner geometry. The complex was applied as an efficient homogeneous catalyst in C-C coupling Heck reaction of arylhalides with olefins such as methylacrylate. Investigation of the catalytic activity of the complex in Heck reaction between arylhalides and olefins showed high yield and selectivity. For example reaction between iodobenzene and...
Formulation and Properties of Scaffolds based on Hydroxyapatite Composites Containing Titanium Dioxide and Magnesium Oxide
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor)
Abstract
This study investigates the effect of titanium dioxide and magnesium oxide additives on hydroxyapatite synthesized by sol-gel and composite with the predominant phase of hydroxyapatite by in situ method to improve mechanical properties. Scaffold samples were synthesized with nanometer-sized hydroxyapatite and composite powder particles by gel casting and sintered at 1200 ° C. Then, to evaluate the synthesized powders, simultaneous thermal analysis (STA), X-ray diffraction test, FTIR test, FESEM, EDS, and MAP analysis were used. Also, to evaluate the mechanical properties of the scaffolds, a compressive test was used, and to evaluate the scaffolds' density, the Archimedes method was used....
Optimization of the Capability of Native Microorganisms Isolated from the Landfill of Electronic Wastes in Bioleaching of E-Waste
, M.Sc. Thesis Sharif University of Technology ; Yaghmaei, Soheila (Supervisor)
Abstract
Given the complex structure of electronic waste and the difficulty of recycling it by traditional methods, the focus is mainly on biohydrometallurgy method, and in particular on bioleaching. To recover metals, various microorganisms are utilized in this method. In light of previous studies, cyanogenic bacteria have been widely used for the extraction of basic and precious metals. Among the species, indigenous microorganisms have a higher ability to resist toxic environments in the bioleaching of metals due to their adaptation by rapid changes in their metabolic system over time. The main objective of this study is to isolate indigenous microorganisms from electronic waste landfill for their...
Prediction of Flow Profiles in Different Well Layers using Fiber Optic Data Analysis
, M.Sc. Thesis Sharif University of Technology ; Bazargan, Mohammad (Supervisor)
Abstract
Downhole temperature measurement is one of the key tools for monitoring and analyzing the performance of production wells, evaluating water injection, and identifying multiphase flows within wells. The development of fiber optic technology and tools such as distributed temperature sensors has enabled the recording of high-resolution and detailed temperature profiles. These data, which measure temperature over a wide range along the wellbore, allow researchers to analyze complex downhole processes and identify fluid entry from various reservoir layers. However, accurately distinguishing the contribution of each layer to the total flow rate, especially under multiphase flow conditions and...
Climate Change and Mortality: Evidence from Iran
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor)
Abstract
Due to the prominence of the evaluation of the consequences of rising temperatures, this paper examines the effects of temperature variation on mortality across different demographic groups in Iran. I use a rich weekly data set from 2009 to 2017 across different demographic groups to understand the potential health impacts of climate change in a developing country. Using several fixed effect regressions, I discover that for an additional day with a mean temperature over 25°C, mortality rate increases by 2.56% relative to the effects of an extra day in 0-5 °C, in the weekly temperature exposure horizon. I test for the harvesting effect by comparing the estimates at weekly and monthly...
Adsorption and dissociation of hydrogen peroxide on small Pd xM3-x (M = Pt, Cu; X = 1-3) clusters: A hybrid density functional study
, Article Molecular Physics ; Volume 109, Issue 14 , May , 2011 , Pages 1797-1804 ; 00268976 (ISSN) ; Gobal, F ; Arab, R ; Sharif University of Technology
2011
Abstract
The adsorption and dissociation of H2O2 on small PdxM3-x (M=Pt, Cu; x = 1-3) clusters is investigated using the B3PW91 hybrid density functional method. Natural bond orbitals are analysed to obtain partial charges on atoms, dipole moments, bond orders, and hybrid orbitals of the PdxM3-x-H2O2 systems. The calculated adsorption energies are in the range of -0.32 to -2.12 eV. Generally, H2O2 adsorbs on top positions through one of its oxygen atoms and only in a few cases reacts with the cluster through both oxygen and hydrogen sides. In the latter case the cluster sites which are negatively charged interact with the hydrogen atoms. Interestingly, on the triplet Pd2Pt cluster, H2O2 dissociates...
Determination of antioxidant component and activity of rice bran extract
, Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1402-1406 ; 10263098 (ISSN) ; Alemzadeh, I ; Maghsoudi, V ; Sharif University of Technology
2011
Abstract
Rice bran is one of the most important co-products in the rice milling. In this research, antioxidant activity of two Iranian rice bran varieties, Fajr and Tarem, extracted by three different solvents (methanol, ethanol and ethyl acetate) was evaluated. The order of antioxidant activity was evaluated by measurement of total phenolic content, antioxidant activity in linoleic acid system, reducing power and scavenging capacity by DPPH radical. The methanolic extract of Fajr rice bran showed a total phenolic content of 3.31 mg Gallic acid/gr rice bran and a DPPH free radical-scavenging activity of 93.91%, achieved at 50 mg/ml concentration, and a percent inhibition of linoleic acid peroxidation...
DFT study of nitrogen monoxide adsorption and dissociation on Rh[sbnd]Cu nano clusters
, Article Journal of Alloys and Compounds ; Volume 695 , 2017 , Pages 1924-1929 ; 09258388 (ISSN) ; Nahali, M ; Gobal, F ; Sharif University of Technology
2017
Abstract
Adsorption and dissociation of NO on RhxCu4-x(x = 0–4) nano clusters were investigated using density functional theory. Adsorption energy, total charge on NO, NO bond length, and NO vibrational frequency for various modes of NO adsorption were analyzed. Adsorption from the nitrogen end of NO on the Rh atom(s) of the clusters are more favored and adsorption energies are in the −1.02 eV to −2.59 eV range. NO binds stronger to Rh-Cu mixed clusters compared to pure Cu4 cluster, so N[sbnd]O bond is significantly weakened upon adsorption on the former. NO binding to more atoms of the clusters results in a corresponding decrease of the N[sbnd]O vibrational frequency. Dissociation of NO was also...
Effect of Equal Channel Angular Pressing(ECAP) Parameters on Microstructure and Mechanical Properties of Strip Samples of AZ31 Mg Alloy
, M.Sc. Thesis Sharif University of Technology ; Akbarzadeh Changiz, Abbas (Supervisor)
Abstract
Equal Channel angular pressing (ECAP) is one of the most applicable Severe Plastic Deformation (SPD) Procedures which results in improvement of strength and ductility through grain refinement and an appropriate texture development. In this study, in order to achieve a proper orientation and microstructure, ECAP was performed in different routes and temperatures up to 4 passes on AZ31 magnesium alloy. Microstructure and mechanical properties were studied. X-ray diffraction analysis was performed to study the basal orientation variation and calculation of sub-grain size. In addition, cold rolling at room temperature was done on the fourth pass specimens, in order to study the effect of ECAP...
A Hybrid Simulated Annealing Algorithm For Winner Determination problem In Combinatorial Auction
, M.Sc. Thesis Sharif University of Technology ; Kianfar, Farhad (Supervisor)
Abstract
One of the most important issues that an organization faced with is resource management. The proper resource management has the great rule in organization cost reduction. One of the most efficient processes in resource allocation is auction and there is different auction with different mechanism and goals. In an auction there is a set of items and a set of bids, and the task of auctioneer is matching items with suitable bids. Each bid consist of desirable items and the bidder value of that items. In an auction process, after mechanism design of auction and auction implementation we must identify the winners of auction and this is a hard problem even in simple auction.
In this study we...
In this study we...
A No-Wait Flowshop Scheduling Problem with Sequence Dependent Setup Time
, M.Sc. Thesis Sharif University of Technology ; Salmasi, Nasser (Supervisor)
Abstract
In this research a no-wait flowshop sequence dependent setup time scheduling problem with weighted earliness-tardiness penalties as the criterion (F_m |nwt,S_ijk |∑▒〖w_j^' E_j+w_j^" T_j 〗) is investigated. It is assumed that n jobs are assigned to a flowshop with m machines. The jobs are not allowed to wait between two successive machines according to no-wait requirement. Moreover each machine needs a setup time before processing a new job. The value of this setup time is dependent on the previous processed job on that machine.
A mixed integer linear programming model is proposed to solve the problem. As the problem is shown to be strongly NP-hard, a particle swarm optimization (PSO)...
A mixed integer linear programming model is proposed to solve the problem. As the problem is shown to be strongly NP-hard, a particle swarm optimization (PSO)...