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jamshidi-vismeh--alireza
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Investigation into the Effects of Using Various Thermal Insulators on the Behaviour of Structural Connections During Fire
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Steel is a non-combustible material, but at high temperatures, steel structures, due to their diminishing yield strength, undergo a considerable visco-plastic deflection, which results in a reduction in their load bearing capacity. Thus, to increase safety against fire must be considered as an important objective in the design and construction of steel structures. One of the safety measures which can be taken against fire is to increase the resistance of the structure against heat by using heat-resistant coatings. This decreases the rate of transfer of heat to the structure, and must include the ‘structural members’ and ‘structural joints’. Due to the role of structural connections in...
Evaluation of Different Multi-objective Approaches to Distribution Network Planning
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
Power distribution network planning and related optimization is an interesting research subject and many papers have been published on this topic. Distribution network planning started in developed countries. Therefore network models are based on reliable network data, educated crew and low interest rate. Nowadays, Iranian engineers and researches try to use their research result for solving network optimization problems but sometimes the result of optimization is not achievable in reality. In current thesis, modeling approaches developed by previous researchers were compared and the effect of model simplification was evaluated. This evaluation was based on data gathered from local power...
Simulation of 2-Phase Fluid Flow on Unstructured Grids Upscaled by Image Segmentation Methods
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor) ; Hajizadeh, Alireza (Co-Advisor)
Abstract
This paper describes the use of Quad-Tree Decomposition for upscaling of absolute permeability 2D geological models. Quad-Tree Decomposition is a data structure and generates an unstructured upscaled model that preserves the heterogeneity of the original geological model. In other words, in high-variability regions of the geological model, the gridblocks of the upscaled model remain small but in other regions that the permeability variation is low, the gridblocks of the upscaled model are coarsened. Quad-Tree Decomposition is a very simple, efficient and robust method that reduces the total number of gridblocks and results to high saving in time and memory required to flow simulation in the...
A novel structural joint with the potential of fire-tolerance improvement
, Article 24th International Conference on Offshore Mechanics and Arctic Engineering, 2005, Halkidiki, 12 June 2005 through 17 June 2005 ; Volume 1 B , 2005 , Pages 747-754 ; Jamshidi Vismeh, A. R ; England, G. L ; Fattahian, N ; Sharif University of Technology
2005
Abstract
A new innovative 'universal' structural joint with multiple applications was devised. The two major conceived contexts for the use of this joint are 'joining beams to columns, ' and 'joining diagonal braces to horizontal ones. ' The main features of this joint are its high rotational capacity, its high shear deformation capacity, its high energy-dissipation capacity, its ability to contain damage, and its repalceability. Due to its geometry, it can well lend itself to protection measures against fire, normally practiced by the involving industries. This makes it a good candidate for being used in structures related to oil and gas industry, offshore or onshore. Through numerical modelling of...
Theoretical Investigation of Hydrogen Bonding Effects on Interaction of Metal Nanoclusters with Histidine, Oxidation of Olefins by MnO4– & Acidity Enhancement of Alcohols
, Ph.D. Dissertation Sharif University of Technology ; Fattahi, Alireza (Supervisor) ; Mahmoodi Hashemi, Mohammad (Supervisor) ; Jamshidi, Zahra (Supervisor)
Abstract
This thesis is divided into three parts: In part I, interactions of neutral and anionic forms of histidine with coinage metal nano clusters M3 (M = Au, Ag and Cu) are investigated. Results demonstrate that nonconventional M…H-O hydrogen bonds and M-X bonds (X = N, O) play stabilization roles in interactions of histidine and metal nano clusters. Presence of negative charge in ligand leads to increase of binding energy of complexes. In the next step, the effects of coinage metal nano clusters on the gas-phase acidity of weak organic acid (histidine) have been explored. The acidity of isolated histidine is compared with the acidity of its Au3–, Ag3– and Cu3–complexed species. Moreover, pKa...
Theoretical Investigation of Hydrogen Bonding Effects on Interaction of Metal Nanoclusters with Biomolecules & Acidity Enhancement of Alcohols
, Ph.D. Dissertation Sharif University of Technology ; Fattahi, Alireza (Supervisor) ; Mahmoodi Hashemi, Mohammad (Supervisor) ; Jamshidi, Zahra (Co-Advisor)
Abstract
This thesis is divided into three parts: In part I, conformational properties of neutral, anionic, cationic and zwitterionic forms of glutathione tripeptide were investigated by means of DFT-B3LYP method with 6-31+G (d,p) basis set. Results show that glutathione is a very flexible molecule and its conformational energy landscape is strongly influenced by forming intramolecular hydrogen bond and its charge. Conformation of each amino acid in glutathione tripeptide depends on its orientation within the peptide sequence in addition to the conformation of other amino acids within the chain. Investigation of intramolecular hydrogen bonds in these conformers by means of AIM analysis demonstrates...
Performance analysis of spectral-phase-encoded optical CDMA system using two-photon-absorption receiver structure for asynchronous and slot-level synchronous transmitters
, Article Journal of Lightwave Technology ; 2007, Volume 25, Issue 6, Pages 1638-1645 ; Salehi, J. A ; Sharif University Of Technology
Abstract
In this paper, we analyze the performance of a nonlinear two-photon-absorption (TPA) receiver and compare its performance with that of a single-photon-absorption (SPA) receiver in the context of spectral-phase-encoded optical code-division multiple access (CDMA) technique. The performances for the above systems are evaluated for two different transmission scenarios, namely, asynchronous and slot-level synchronous transmitters. Performance evaluation includes different sources of degradation such as multiple-access interference, noise due to optical amplification, shot noise, and thermal noise. In obtaining the performance, the mean and variance of the received signal in each of the above...
Statistical characterization and the bit- error- rate analysis of lightwave systems with optical amplification using two-photon absorption receiver structures
, Article IEEE/OSA Journal of Lightwave Technology ; 2006 Vol. 24, Issue 3, PP. 1302-1316 ; Salehi, J. A ; Sharif University Of Technology
Abstract
In this paper, the authors study the performance of a two-photon absorption (TPA) receiver in a typical communication system employing an optical amplifier. For the study, the authors develop a comprehensive performance analysis, taking into account noises due to an optical amplifier, shot noise, and thermal noise, using Gaussian approximation technique. In evaluating the performance of the system using this technique, the mean and the variance of the received signal will be derived. Comparing the results of receivers using the TPA process with that of a typical single-photon absorption (SPA) structure leads the authors to conclude that TPA receivers can be used when the speed of the...
Statistical analysis of coherent ultrashort light pulse CDMA with multiple optical amplifiers using additive noise model
, Article IEEE/OSA Journal of Lightwave Technology ; Vol. 23, No. 5, PP. 1842-1851, May 2005 ; Salehi, J. A ; Sharif University Of Technology
Abstract
This paper describes a study of the performance of various configurations for placing multiple optical amplifiers in a typical coherent ultrashort light pulse code-division multiple access (CULP-CDMA) communication system using the additive noise model. For this study, a comprehensive performance analysis was developed that takes into account multiple-access noise, noise due to optical amplifiers, and thermal noise using the saddle-point approximation technique. Prior to obtaining the overall system performance, the input/output statistical models for different elements of the system such as encoders/decoders, star coupler, and optical amplifiers were obtained. Performance comparisons...
Optimal design of two-dimensional porosity distribution in shear deformable functionally graded porous beams for stability analysis
, Article Thin-Walled Structures ; Volume 120 , 2017 , Pages 81-90 ; 02638231 (ISSN) ; Arghavani, J ; Sharif University of Technology
2017
Abstract
In the present study, considering two-dimensional porosity distribution through a functionally graded porous (FGP) beam, its optimal distributions are obtained. A multi-objective optimization problem is defined to maximize critical buckling load and minimize mass of the beam, simultaneously. To this end, Timoshenko beam theory is employed and equilibrium equations for two-dimensional functionally graded porous (2D-FGP) beam are derived. For the solution, we present generalized differential quadrature method (GDQM) and consider two symmetric boundary conditions (Clamped-Clamped and Hinged-Hinged). Solving generalized eigenvalue problem, critical buckling load for 2D-FGP beam is then obtained....
Optimal material tailoring of functionally graded porous beams for buckling and free vibration behaviors
, Article Mechanics Research Communications ; Volume 88 , 2018 , Pages 19-24 ; 00936413 (ISSN) ; Arghavani, J ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this paper, assuming porosity varies only along thickness direction, its optimal distributions in functionally graded porous (FGP) beams are tailored. Two multi-objective optimization problems are defined. In the first one, critical buckling load and mass are optimized simultaneously while in the second one, we concentrate on simultaneous optimization of mass and fundamental frequency. Employing Timoshenko beam theory, we present governing equations for a FGP beam. For the solution, we use Ritz method and propose appropriate trial functions according to the boundary conditions (Hinged-Hinged, Clamped-Clamped, Clamped-Hinged and Clamped-Free). Since the porosity distribution along...
On the dissemination of the discourse of going: The case of Iranian for-profit study abroad institution's chronotopic representation of ideal life there
, Article Language and Communication ; Volume 80 , September , 2021 , Pages 11-24 ; 02715309 (ISSN) ; Rezaei, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This research addresses the escalation of the ‘discourse of going’ among Iranian educated people in recent years through highlighting the influential role played by for-profit study abroad institutions. Utilizing a discourse-analytic approach, we engage the theoretical concept of chronotope, caliberation, and commodification to investigate the ways through which for-profit study abroad institutions represent the images of ‘life beyond’. The data were obtained in interview sessions with ten certified Iranian study-abroad institutions. The results of the data analysis revealed two main themes, namely, hypothetical utopia there and dystopia here as well as success here-and-now and...
Security Evaluation of Public Key Based Key Management in MANET
, M.Sc. Thesis Sharif University of Technology ; Mohajeri, Javad (Supervisor)
Abstract
Due to popularity of mobile wireless devices, security of mobile ad hoc networks (MANETs) being more important than before. Traditional key management schemes based on symmetric key cryptography are became ineffective because of dynamic and infrastructureless nature of these networks.Recent studies are mainly based on traditional public key cryptography schemes and ID-based cryptography schemes. On the other hand, Contributory schemes seem suitable for MANETs because of their inherent self-organize property. Key update and Key revocation are the fundamental issues of key management schemes in mobile ad hoc networks. Certificateless public key cryptography, in addition to solve those issues,...
Application of Pore Network Modeling in Study of Rock Typing Algorithms
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
One of the most important issues in modeling and simulation of reservoirs is determination of different rock types or Rock Typing. In this study, after a brief review of some conventional methods for rock typing, their capabilities have been investigated. In this way, for the first time, pore network modeling is used as a tool for validating the rock typing methods. By using flow simulation in porous medium with pore network modeling approach, similar rock types data have been generated and these artificially data have been used for validating of rock typing methods. To form more realistic pore networks, both regular and irregular pore network have been modeled and analyzed. Pore size...
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...
Study of ESP and Gas Lift Applications On low Productivity Wells of Alvand Oil Field
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
Alavand Oil field is located 50 Km away from west of Siri Island and includes DPG and DPH platforms. The production from Alavand field started in 1998 and till now 11 wells have been totally drilled .Since a production peak in 2001, the oil production in Alvand field has decreased. Water cut is increasing and reservoir pressure is decreasing gradually. Considering poor reservoir characteristic of this reservoir, productivity indexes of wells are relatively low. In addition; natural depletion of reservoir caused the wells to be unable to flow naturally and either closed or produce periodically consequently. To increase production and extend the lifetime of Alvand field, it is decided to start...
Modelling Point and non Point Source of Nitrate with SWAT in the Jajrood River Watershed
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor)
Abstract
To investigate boiling heat transfer characteristics of nanofluids, transient quenching¬ experiments of a high temperature silver sphere in water-based nanofluids with Ag and TiO2 nanoparticles were performed. A silver sphere of 10 mm in diameter at the initial temperature of 700o C was quenched in the nanofluids at the temperature of 90o C. The results showed considerable reduction in the quenching ability of nanofluids compared to that of pure water. The presence of nanoparticles in water caused film boiling mode to vanish at lower temperatures depending on the mixture concentration. Computed heat transfer rates in nanofluids were lower than those in pure water. In the quenching...
Pore scale acidizing Simulation Using Lattice Boltzmann Method
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeed (Supervisor)
Abstract
Matrix acidizing aims at bypassing near wellbore damages in typical carbonate reservoirs or enhancing permeability and hydraulic conductivity in naturally fracture ones. The simulation of acidizing process at pore scale and complex geometries by LBM will lead to gain more knowledge about molecular mechanisms that govern rock dissolution, diffusion and advection of reactive fluid and help the evaluation of acidizing efficiency.In this thesis, simulation of acidizing includes the following steps:
• Multicomponent fluid convection
• Fluid diffusion into the solid
• Fluid-rock reaction
• Boundary conditions including periodic, bounceback, non-equilibrium bounceback, Dirichlet,...
• Multicomponent fluid convection
• Fluid diffusion into the solid
• Fluid-rock reaction
• Boundary conditions including periodic, bounceback, non-equilibrium bounceback, Dirichlet,...
On the Effects of Background Electromagnetic elds and Chiral Chemical Potential on the Phase Diagram of Quantum Chromodynamics
, M.Sc. Thesis Sharif University of Technology ; Sadooghi, Neda (Supervisor)
Abstract
In particle physics, spontaneous chiral symmetry breaking generates new phases of quark matter, and leads to significant changes od quark masses. The Nambu-Jona–Lasinio (NJL) model is a useful fermionic model which describes the spontaneous chiral symmetry breaking through the creation of a condensate. This model can be for instance used to determine various phases of Quantum Chromodynamics (QCD) in finite electromagnetic fields. This work consists of several parts. First, we describe the spontaneous chiral symmetry breaking in detail. Second, we extract the NJL model from the Lagrangian density of QCD. Third, we derive a covariant form of the partition function of a fermionic system....
Providing a Solving Method for Post-Earthquake Resource Allocation Model with Uncertainties
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
Large amounts of relief resources such as water, tents, medical equipment and fuel after a major disaster need to reach the affected people. Satisfying the needs of victims is crucial to the success of crisis relief operations, as a lack of relief resources can lead to the suffering and loss of lives of victims. According to studies, large-scale catastrophes have occurred frequently in recent years. Therefore, it is necessary to pay more attention to the management of post-crisis resources. Since the distribution of emergency resources depends largely on the efficiency and effectiveness of logistics operations, the primary objectives include minimizing logistics time and cost, minimizing...