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Applying Infrared Thermography for Monitoring the Condition and Failure Diagnosis of Power Network
, M.Sc. Thesis Sharif University of Technology ; Ghodrati, Behzad (Supervisor)
Abstract
Temperature and the resulting thermal behavior of electric power generation and distribution equipment and industrial electrical systems and processes are the most critical factors in the reliability of any operation or facility. Temperature is by far the most measured quantity in any industrial environment. For these reasons, monitoring the thermal operating condition of electrical and electromechanical equipment is considered to be a key factor to increasing operational reliability. Infrared thermography (IR/T) as a condition monitoring technique is used to remotely gather thermal information for monitoring the condition of virtually all of the electrical components on an entire system and...
Analysis and Verification of a Routing Protocol Conformance Test Program
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor)
Abstract
Routers play a key role in transferring information between various Networks. It is very important to make sure about the compatibility of OSPF in a router with its standard description. In this regard, before presenting or applying a router and also evaluating its performance, it is necessary to carry out conformance test with the help of network equipment testers Tester designers extract test cases from protocol standard description through non-formal ways and exam them on network equipment.
In this thesis, a part of OSFP protocol has been modeled through colored Petri nets. In this regard, two sections of OSPF RFC have been model checked: neighbor state machine and data base...
In this thesis, a part of OSFP protocol has been modeled through colored Petri nets. In this regard, two sections of OSPF RFC have been model checked: neighbor state machine and data base...
Skiptree: a new scalable distributed data structure on multidimensional data supporting range-queries
, Article Computer Communications ; Volume 33, Issue 1 , 2010 , Pages 73-82 ; 01403664 (ISSN) ; Ghodsi, M ; Toossi, M ; Sharif University of Technology
2010
Abstract
This paper presents a new balanced, distributed data structure for storing data with multidimensional keys in a peer-to-peer network. It supports range queries as well as single point queries which are routed in O (log n) hops. Our structure, called SkipTree, is fully decentralized with each node being connected to O (log n) other nodes. We propose modifications to the structures, so that the memory usage for maintaining the link structure at each node is reduced from the worst case of O (n) to O (log n log log n) on the average and O (log2 n) in the worst case. It is also shown that the load balancing is guaranteed to be within a constant factor. Our experimental results verify our...
Propose a New Theory about Religious Language Problem
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hassan (Supervisor)
Abstract
During last century, one of the most important philosophy of religious field issues, especially after 1950 was religious language. In other words, one of the most important and affective problems which could attract philosophers was religious language problem. This issue also has a history resume. Ask about religious language, at least could be seen by philosophers of Abrahamic religion like Islam and Christian. However, during last century due to philosophic attention to the language, religious language became for another time, an important problem. In this thesis, first of all, a geographic view of questions and answers will be caught by reviewing theories, from past until now. This would...
Implementation and Analysis of Optical Isolation using Reciprocal and Nonreciprocal Elements
, M.Sc. Thesis Sharif University of Technology ; Mehrany, Khashayar (Supervisor)
Abstract
In this thesis we study the possibility of unidirectional transmission of light using reciprocal and nonreciprocal elements. Unidirectional transmission will allow us to separate the coupling of light into and out of resonators and design unidirectional waveguides. We start by studying the effects of one-sided modulations of dielectric constant of reciprocal structures. One-sided modulation will satisfy the phase matching condition for the coupling of two waves only in one direction. Using coupled mode theory, we study one sided modulation in layered media. Next, we find the exact solution to such strucures using transfer matrix method and analyze one-sided modulation in waveguide...
Investigation on Friction Stir Lap Welding of Al-5083 Sheet to St-12 Sheet and to Al-1100 Clad St-12 Sheet
, Ph.D. Dissertation Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Seyed Reihani, Morteza (Supervisor)
Abstract
In this study, friction stir lap welding of Al-5083 alloy sheets with 3 mm thickness to St-12 steel sheets with 1 mm thickness (joint without intermediate layer) and to Al-1100 clad St-12 sheets (joint with the Al-1100 intermediate layer) was investigated. The cladding process was done by rolling. For each type of joints, the bonding mechanism, optimum process parameters to reach the joints with the highest fracture loads and also the microstructure evolutions at the joint region were studied. Furthermore, for the joints without intermediate layer, the effects of the Al-5083 annealing treatment before welding and the post-weld heat treatment of the joints on the fracture loads were explored....
Feasibility Study on Fabrication of Copper-Graphite and Copper-Babbitt Composites by Friction Stir Processing (FSP)
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Seyed Reihani, Morteza (Supervisor)
Abstract
Because of low friction coefficient, Copper-Graphite and Copper-Babbitt composites can be used as brushes and bearing materials instead of materials containing lead which cause environmental problems. So far, many methods such as powder metallurgy and centrifugal casting have been used to fabricate Copper-Graphite composites. The most important problem of these methods is agglomeration of Graphite particles. Simultaneous stirring of samples during fabrication process which is one of the features of friction stir processing (FSP), can solve the problem. Recently, FSP has been used for fabricating surface composite for the purpose of producing hard and wear resistance layers on ductile...
Synthesis and Characterization of Wound Dressings based on Alginate-Quince Seed Gum
, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza (Supervisor) ; Seyed Reihani, Morteza (Supervisor)
Abstract
Quince seed gum is a natural material that was used in Iranian traditional medicine for wound treatment. Alginate is a beneficial biomaterial that has been used in making commercial wound dressings for a long time. In this work, the preparation method and properties of films based on Alginate and Quince seed gum for drug delivery and wound healing have been investigated. According to the obtained results about crosslinking and plasticizing, the suitable condition of synthesis is 0.5% CaCl2 concentration, 2min soaking time, and 13% glycerol in crosslinking solution. In this crosslinking solution, a film with good mechanical properties (tensile strength: 13MPa, elongation: 27.3%, and Young’s...
A stochastic approach for valuing customers in banking industry: A case study
, Article Industrial Engineering and Management Systems ; Volume 19, Issue 4 , 2021 , Pages 744-757 ; 15987248 (ISSN) ; Mehraeen, M ; Pooya, A ; Sharif, H ; Sharif University of Technology
Korean Institute of Industrial Engineers
2021
Abstract
This study provides a stochastic dynamic programming model with a Markov chain that explicitly focuses on the customer as well as a new model for valuing the customers in the banking industry. The proposed framework calculates individual customer’s lifetime value dynamically. The study follows a stochastic dynamic programming model that is based on the Markov chain. The deduced findings are illustrated with supplementary context from an outstanding case study. The findings underline the importance of the stochastic model for calculating customer lifetime value based on customer behavior. The presented framework provides a beneficial way for future research and valuable insight for allocating...
Modeling of Dissolution of Sluge from Evaporation Lagoons of Isfahan's UCF Plant
, M.Sc. Thesis Sharif University of Technology ; Samadfam, Mohammad (Supervisor) ; Charkhi, Amir (Supervisor) ; Otukesh, Mohammad (Co-Advisor)
Abstract
Uranium conversion process is one of the most important stages in nuclear fuel cycle. The Uranium Conversion Facilities (UFC) of Iran is located in Isfahan. In this plant, the Yellowcake (impure uranium oxide, U3O8) is converted to Uranium hexa-fluoride, UF6. During the process, considerable amounts of uranium-containing liquid waste are generated. This liquid waste was collected in evaporation pools inside the UCF Plant. In the course of time, a thick layer of precipitated salt form in bottom of the pools which are collected and stored in drums inside a building. This solid waste contains uranium at concentration levels much higher than that permitted for land disposal of the waste....
Dissimilar Friction Stir Welding between Aluminum Alloy and Magnesium Alloy
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Seyed Reihani, Morteza (Supervisor)
Abstract
In this project, Dissimilar Friction Stir Welding (FSW) between aluminum alloys (1100-H12 and 5083-O) and Magnesium alloy (AZ31B-O) with 3mm thickness were butt joined. Fusion welding of aluminum/magnesium alloys has failed because of forming much more intermetallic compounds. By using friction stir welded samples, effect of welding parameters such as tool travel speed, tool rotation rate, tool position respect to weld centerline, and sheet position respect to tool direction on mechanical (tensile strength, yield strength and elongation) and microstructural properties of the welds were investigated. After several tests, range of optimum parameters were obtained. In both 1100 and 5083 alloys,...
Design and Fabrication of a Device for Positioning Magnetic Micro Robot
, M.Sc. Thesis Sharif University of Technology ; Nejat, Hossein (Supervisor) ; Vossoughi, Golamreza (Supervisor)
Abstract
At the moment, one of the most important challenges that human beings are struggling with is the dominance of micro and nano dimensions. Considering the potential of microorganisms, and in particular magnetic microscopes, it is believed that using this technology, humans would be able to meet most of their needs. Studies have shown that it is possible to control the position of a magnetic microrobots, through the production of magnetic fields, with sufficient accuracy. Since magnetic fields are biocompatible, magnetic microrobots can also be used in biotechnology and medical applications.In this dissertation, a positioning device was designed and constructed with the ability to position the...
Characterizing twitter with respondent-driven sampling
, Article Proceedings - IEEE 9th International Conference on Dependable, Autonomic and Secure Computing, DASC 2011, 12 December 2011 through 14 December 2011, Sydney, NSW ; 2011 , Pages 1211-1217 ; 9780769546124 (ISBN) ; Rabiee, H. R ; Nabavi, N ; Pooya, S ; Sharif University of Technology
2011
Abstract
Twitter as one of the most important microblogging online social networks has attracted more than 200 million users in recent years. Although there have been several attempts on characterizing the Twitter by using incomplete sampled data, they have not been very successful to estimate the characteristics of the whole network. In this paper, we characterize Twitter by sampling from its social graph and user behaviors through a random walk based sampling technique called Respondent-Driven Sampling (RDS). To the best of our knowledge, for the first time RDS method and its estimator are used in order to obtain uniform unbiased estimation of several key structural and behavioral properties of...
Studying of the Single Top Quark Produced by Anomalous Interactions Tcg and Tug
, M.Sc. Thesis Sharif University of Technology ; Ardalan,Farhad (Supervisor) ; Mohammadi Najafabadi, Mojtaba (Supervisor)
Abstract
Anomalous top quark interactions with gluon (tug , tcg) allow the production of single top quarks at the LHC. Two main sources of backgrounds which we took into account are W +1j and standard model single top production. In order to do it, we examine the reconstructed angular distribution of the charged lepton in the rest frame of W boson from the top quark. It is defined in terms of the angle θ_l , between the charged lepton momentum in the rest frame of the W boson and the momentum of the W boson in the rest frame of the top quark. Using this angular distribution of the charged lepton from the W boson in the top decay، we show that with the data of 10fb^(-1) of integrated luminosity and...
Investigation the Interaction of the Colloidal Particles with Magnetic Cores by Optical Tweezers
, Ph.D. Dissertation Sharif University of Technology ; Seyed Reihani, Seyed Nader (Supervisor) ; Langari, Abdollah (Supervisor)
Abstract
Optimizing optical tweezers and achieving powerful traps has always been a challenging topic for researchers , since the trap stiffness increases with increasing laser power which may damage specimens , especially biological ones and cells . In this thesis , we introduce a special geometry and structure of particles that , have the possibility to increase the stiffness (strength) of the optical trap and cause the magnetic response of particles at optical frequencies . Special geometries such as a combination of dielectric particles with magnetic nanoparticles that emphasize the role of the laser magnetic field and lead to changes in the electrical and magnetic properties at the laser...
A general model for I/O system theory, Proceedings of AIMC31 [electronic resource]
, Article Iranian Journal of Fuzzy Systems ; 2006, Volume 3, Issue 2, Page 1-19 ; Hashem, Amir ; Sharif University of TechnologyStanley depth of the integral closure of monomial ideals
, Article Collectanea Mathematica ; Volume 64, Issue 3 , November , 2013 , Pages 351-362 ; 00100757 (ISSN) ; Sharif University of Technology
2013
Abstract
Let I be a monomial ideal in the polynomial ring S=K [x1,... xn]. We study the Stanley depth of the integral closure Ī of I. We prove that for every integer k ≥ 1, the inequalities (S/Ik) ≤ sdepth (S/Ī) and sdepth(Ik) ≤ sdepth(Ī) hold. We also prove that for every monomial ideal I⊂ S there exist integers k1,k2≥ 1, such that for every s≥ 1, the inequalities sdepth (S/Isk1) ≤ sdepth(S/Ī) and sdepth (Isk2) ≤ sdepth (Ī) hold. In particular, mink{sdepth(S/Ik)} ≤ sdepth(S/Ī) and min̄k {sdepth (Ik)}≤ sdepth(Ī). We conjecture that for every integrally closed monomial ideal I, the inequalities sdepth(S/I)≥ n-l (I) and sdepth (I)≥ n-l (I)+1 hold, where l (I) is the analytic spread of I. Assuming the...
Dynamic modeling and sensitivity analysis of atomic force microscope pushing force in nanoparticle manipulation on a rough substrate [electronic resource]
, Article Journal of Advanced Science, Engineering and Medicine ; 2013, Vol. 5, pp. 1-10 ; Mahboobi, Seyed Hanif ; Meghdari, Ali ; Sharif University of Technology
Abstract
An Atomic Force Microscope (AFM) is a capable tool to manipulate nanoparticles by exerting pushing force on the nanoparticles located on the substrate. In reality, the substrate cannot be considered as a smooth surface particularly at the nanoscale. Hence, the particle may encounter a step on the substrate during a manipulation. In this study, dynamics of the nanoparticle on a stepped substrate and critical pushing force in the manipulation are investigated. There are two possible dynamic modes that may happen in the manipulation on the stepped substrate. In one mode, the nanoparticle may slide on the step edge and then climb up to the step which is a desired mode. Another possible mode is...
Simulation of static recrystallization in non-isothermal annealing using a coupled cellular automata and finite element model
, Article Computational Materials Science ; Volume 53, Issue 1 , 2012 , Pages 145-152 ; 09270256 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
2012
Abstract
A coupled cellular automata and finite element model has been proposed to evaluate static recrystallization kinetics during non-isothermal annealing of cold deformed low carbon steels. The effects of various factors including heating rate, annealing temperature, and initial microstructures have been considered in the model to accurately predict the static recrystallization kinetics and the final microstructures. In order to examine the employed algorithm, the predicted results have been compared with the experimental observations and a good agreement was found between the two sets of results
A neural network model for prediction of static recrystallization kinetics under non-isothermal conditions
, Article Computational Materials Science ; Volume 49, Issue 4 , 2010 , Pages 773-781 ; 09270256 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
2010
Abstract
This paper presents a new scheme to apply artificial neural network (ANN) in prediction of static recrystallization (SRX) kinetics. Firstly, based on empirical data of SRX kinetics, a mathematical model is suggested to construct a neural network. Then, an appropriate neural network is trained on the basis of the first and the second derivatives of recrystallized fraction with respect to time. Finally, a thermo-mechanical finite element analysis is coupled with the proposed ANN to predict static recrystallization kinetics in hot rolling process of AA5083. To verify the model, the predicted results and the experimental data are compared and it is observed that there is a good consistency...