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mansouri--mohammad
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Algorithms for Tracking Moving Points
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
Nowadays binary sensors such as infrared sensors are vastly employed in industrial, commercial and general applications due to their simplicity and low price. Beam sensors are common type of these sensors which can detect objects when they cross its beam. Sequence of sensors which are crossed in a time order is called sensor word. Consider an object, produced sensor word shows the order which it has crossed the beams. If we have more than one object then sensor word is combination of all sensor words produced by all object. We need to separate each sensor word. In this research, sensor word is developed to Fixed-Charge Minimum Cost Maximum Flow Network type.In this case, the consequent...
Dynamics of a Test Particle Within a Cosmological Structure and the General Relativistic Masses
, M.Sc. Thesis Sharif University of Technology ; Mansouri, Reza (Supervisor)
Abstract
Using a general relativistic model for structures in a cosmological background, we calculated the Geodesics within a structure such as a galaxy or a cluster of galaxies in order to obtain the velocity profile of stars or galaxies. The profile defines a Newtonian mass which is then compared to different local gravitational masses, such as Misner-Sharp, Liu-Ya and ... to see how different they are. In this project we used numerical methods for solving geodesics equations of LTB metric and Einstein’s field
equations.
equations.
Predicting Stock Index Movement by Maching Learning and Data Mining Techniques Using Financial News and Macroecomic Factors Data
, Ph.D. Dissertation Sharif University of Technology ; Modarres Yazdi, Mohammad (Supervisor)
Abstract
Nowadays, stock index forecasting has become an important issue for decision makers as well as investors, and such a forcasting is increasingly difficult thanks to multifarious impact of factors. In this regard, machine learning approaches can be used to analyze and predict the stock index and its influencing factors. Such an approach not only provides decision makers to make more becoming decision associated with the monetary and financial sectors of the country, but also allows investors to chose more appropriate portfolio (lower risk) by forecast long-term stock.In this study, we intend to better predict the stock index based on the necessity by examining the economic factors affecting...
Manipulation of Two-Dimensional Nanosheets Tin Sulfide by Solvothermal Process
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
Tin sulfide with an energy gap of about 1.1 ev is a semiconductor suitable for applications such as solar cells, lithium-ion batteries, photocatalysts and other semiconductor-based devices. There are several methods for synthesizing this semiconductor at the nanometer scale, among which the solvothermal method is an efficient, controllable and inexpensive method. By precisely controlling the parameters of this process, two-dimensional tin sulfide nanosheets with high purity and desirable morphology can be produced. In this research, tin sulfide has been synthesized by solvothermal / hydrothermal chemical method and its metallurgical properties have been studied. Effect of solvothermal...
Super Heavy Crude Oil Refinery Project Feasibility Study
, M.Sc. Thesis Sharif University of Technology ; Safaeih, Mohammad Reza (Supervisor)
Abstract
The market demand of super heavy crude oil is very low due to its determinative both physical and chemical properties. Unfortunately existing refineries in Iran are not capable to refine this kind of crude oil. Marketing issues besides great price difference with other crude oil types leads us to find economical solution for optimal use of this national possession. About 70 percent of super heavy crude oil produced from Soroush and Norouz oil fields is un-refineable materials and to refine this heavy crude oil to refinery products like gasoline or gas oil a refinery with RFCC ( Residual Fluid Catalitic Cracking) technology must be made. Super high Technology and very heavy capital cost...
Investigating the Effect of Geometry on the Degree of Redundancy and Capacity of Jacket Platform in Wind Turbine Under Wave Load Based on Appropriate Criteria
, M.Sc. Thesis Sharif University of Technology ; Tabeshpour, Mohammad Reza (Supervisor)
Abstract
The use of wind energy due to the clean and unlimited nature of this energy has received more attention and for this purpose, the types of wind turbines that mainly include; monopile turbines and jacket-based turbines; is used In this research project, it has been tried using criteria such as equal weight of structures with different bracing shapes and taking into account the normalized energy and redundancy factors of the platforms; An optimal structure that can achieve a better capacity curve with the same material cost, which includes ultimate stress and greater ductility, and along with all the above factors; The redundancy of the structure has also been considered to minimize the risk...
Phase-induced intensity noise in digital incoherent all-optical tapped-delay line systems [electronic resource]
, Article Lightwave Technology, Journal of ; 2006, Volume.24 , Issue. 8, p.3059-3072 ; Salehi, J. A ; Sharif University of Technology
Abstract
In this paper, the authors analyze conditions under which they can be certain on the intensity addition of a given device, such as tapped-delay lines, used in digital incoherent all-optical communication systems. A general expression for phase-induced intensity noise that is applicable to all types of semiconductor lasers is derived by defining an optical self-SNR expression that can be used to analyze and measure phase-induced intensity noise. The result shows that in order to have a minimal phase-induced intensity noise in most digital optical incoherent systems, a large optical self-SNR, e.g., 20 dB or more, is needed. This in turn is shown to place a limit on the maximum rate of...
Neutronics Calculations of Prismatic High-temperature Gas Cooled Reactor by Deterministic Method Using DONJON and DRAGON Codes and Comparison with Results of Probabilistic Methods (Monte Carlo).
,
M.Sc. Thesis
Sharif University of Technology
;
Ghofrani, Mohammad Bagher
(Supervisor)
Abstract
HTGRs are considered as 4th generation reactors which have prominent characteristics such as inherent safety, lower safety costs, High efficiency and high temperature applications. the most important challenges in developing these reactors is providing appropriate codes in design, simulating their performance and analysis of them. In this thesis, a japanese prismatic HTTR reactor has been selected as a reference reactor and the neurotic’s calculations implementation studied at cold zero power (CZP) and hot full power (HFP) states using DRAGON cell calculation codes and DONJON core computations. At CZP state, One group and two group radial & axial flux distribution, control rod critical...
Iran's science landscape in context
, Article Science ; Volume 354, Issue 6319 , 2016 , Pages 1542-1543 ; 00368075 (ISSN) ; Sharif University of Technology
American Association for the Advancement of Science
2016
Broken promises or promises in vacuum?
, Article Archives of Iranian Medicine ; Volume 11, Issue 5 , September , 2008 , Pages 559-560 ; 10292977 (ISSN) ; Sharif University of Technology
2008
Implementation of Millimeter-wave Imaging Algorithm Based on Frequency Scanning Antenna
, M.Sc. Thesis Sharif University of Technology ; Shabani, Mahdi (Supervisor) ; Kavehvash, Zahra (Supervisor)
Abstract
Nowadays millimeter wave imaging technology has found various applications in industry, medical and security systems. From one side the capability of penetration of this frequency spectrum into non-metal objects, and being harmless to humankind on the other side, has made this spectrum an appropriate alternative instead of dangerous spectrums such as X-ray. Recently, development of millimeter wave electronic circuits and antenna arrays has made the optimal design and implementation of millimeter wave imaging systems feasible. Among actions which have been taken in industry, medical and security systems until now, we can refer to efforts for detection of defects in production line,...
Experimental Study of Forced Convective Heat Transfer Inside a Tube under the Effect of a Rotary Magnetic Ball by Applying an External Magnetic Field Application in Oil and Petrochemical Industry Heat Exchangers
, M.Sc. Thesis Sharif University of Technology ; Kazemzadeh Hannani, Siamak (Supervisor) ; Bijarchi, Mohammad Ali (Supervisor)
Abstract
As cost associated with obtaining energy has escalated on a global level, proper utilization and energy loss prevention has become more important and worthy of consideration. Methods of enhancing forced convection heat transfer through pipes prominently consist of geometry modifications, implementation of more efficient mechanisms and substituting 5 outdated hardware with more effective equipment. In the following paper, a novel technique employing rotation of bipolar magnetic spheres on inner surface of the tube using a rotating magnetic field has been explored for the first time and the outcomes have been promising. The rotating magnetic field is generated by a function generator and a...
General relativistic relation between density contrast and peculiar velocity
, Article International Journal of Modern Physics D ; Volume 11, Issue 3 , 2002 , Pages 321-336 ; 02182718 (ISSN) ; Rahvar, S ; Sharif University of Technology
2002
Abstract
Concepts like peculiar velocity, gravitational force, and power spectrum and their inter-relationships are of utmost importance in the theories of structure formation. The observational implementation of these concepts is usually based on the Newtonian hydro-dynamic equations, but used up to scales where general relativistic effects come in. Using a perturbation of FRW metric in harmonic gauge, we show that the relativistic effects reduce to light cone effects including the expansion of the universe. Within the Newtonian gravitation, the linear perturbation theory of large scale structure formation predicts the peculiar velocity field to be directly proportional to gravitational force due to...
A new distributional approach to signature change
, Article General Relativity and Gravitation ; Volume 32, Issue 2 , 2000 , Pages 253-269 ; 00017701 (ISSN) ; Nozari, K ; Sharif University of Technology
Kluwer Academic/Plenum Publishers
2000
Abstract
Colombeau's generalized functions are used to adapt the distributional approach to singular hypersurfaces in general relativity with signature change. Equations governing the dynamics of a singular hypersurface are derived and a specific non-vanishing form for the energy-momentum tensor of the singular hypersurface is obtained. It is shown that matching in the case of de Sitter space in the Lorentzian sector is possible along the boundary with minimum radius but leads to the vanishing of the energy-momentum tensor of the singular hypersurface
The Role of Cosmological Constant in Gravitational Lensing
, M.Sc. Thesis Sharif University of Technology ; Mansouri, Reza (Supervisor)
Abstract
In present thesis, the effect of cosmological constant, Λ, in bending of light by spherical symmetric mass has been studied. At first we obtain the Schwarzschild-de Sitter solution as spherical symmetric solution of General relativity field equations with cosmological constant, without we suppose the solution is static. Then we obtain gravitational lens equation by considering the space geometry and we benefited from several approach to specify the contribution of cosmological constant to the deflection angle. Furthermore we put new upper bounds on the value of the lambda independently of cosmological constraints. Finally for study the contribution of lambda in gravitational lensing...
Mass Reconstruction of XMM-NEWTON06 Data Based on KSB Method
, M.Sc. Thesis Sharif University of Technology ; Mansouri, Reza (Supervisor)
Abstract
Gravitational lensing affects not only the position and number of images of cosmic objects but also their shapes. In the so-called weak gravitational lensing effects related to shape of the cosmic objects are studied. These require high quality images and wide field of view. Because of technology development and production of multi-chip CCD cameras in recent decades, we are witnessing an increase in the number of projects using weak lensing techniques. Taking instrumental errors into account, the first step in weak lensing studies should be the proper data reduction to produce final images in which instrumental errors are removed and have sufficient precision to be processed. In This thesis...
Steady State and Transient Simulation of Single Spool Turbojet Engine at High Rotational Speeds
, M.Sc. Thesis Sharif University of Technology ; Mazaheri, Karim (Supervisor)
Abstract
In this research, steady state and transient performance of a single spool axial turbojet engine (without afterburner) is studied. Performance maps of main components such as; compressor, combustor and turbine are extracted from a similarity (geometry independent) approach.Then using nested loops method, steady state model of the turbojet engine is developed and using shaft dynamics and volume packing equations, transient model of the turbojet engine is analyzed. Steady state and transient simulations results of an engine are validated by experimental data and then effect of changes on input parameters such as; polar moment of inertia, Mach number, fuel heating value, pressure and...
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
In recent years, the use of embedded processors has grown increasingly in wide range of computer systems; so that most of manufactured CPUs are used in emebedded systems many of which are safty-critical systems such as medical devices, aircraft flight control, space systems, nuclear systems, etc. The incidence of failure in these systems can cause irreversible damages on human life, financial or environmental matters. Silicon process technology trends, such as reducing the threshold voltage, increasing the frequency and decreasing the size of transistors, not only caused increase in single-bit fault rate but also caused occurance of multi-bit faults. Due to importance ofcorrect operation of...
Colloidal Synthesis of CdSe Nanoparticles and the Influence of Processing Parameters on Growth kinetics
, M.Sc. Thesis Sharif University of Technology ; Asgari, Sirous (Supervisor)
Abstract
Over the past two decades, several studies have been investigated on synthesis and properties of semi-conductor quantum dots because of their applications in sensors, LEDs, detectors, solar cells, etc. One of challenging issues in synthesizing these nano-particles is their size distribution. In this study, Cadmium Selenide was synthesized by the method of colloidal synthesis. X-ray diffraction showed that the crystalline nano-particles have wurtzite structure. For obtaining a uniform size distribution, effect of various parameters such as molar ratio of components and reaction temperature on the growth kinetics of these particles, were studied. Results showed that molar ratio of Selenium to...
The Evolution of Spherically Symmetric Perfect Fluid in Inhomogeneous Models
, M.Sc. Thesis Sharif University of Technology ; Mansouri, Reza (Supervisor)
Abstract
We have tried this for the first time to reperesent a comprehensive description of the evolution of a perfect fluid in inhomogeneous relativistic models.We solve Einstein equations using numerical methods.In this procedure we can evaluate the effect of pressure in perfect fluid evolution.Also we look at the behavior of the various horizons, and in the end we will present a cosmological model to a black hole