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morshedi--saeid
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Numerical Study of Heat Transfer Enhancement in Porous Medium by Applying Magnetic Field on Nano Fluid
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, Hani (Supervisor)
Abstract
A 2D simulation has been carried out to study the effect of magnetic field on heat transfer and pressure drop of nanofluid flowing through a pipe filled with porous medium. The nanofluid flow is modeled as a single-phase flow, and Darcy–Brinkman–Forchheimer equation is employed to model fluid flow in porous media. A constant uniform heat flux was imposed on the walls of the cylinder, and the values of Darcy number, Hartmann number, and volume fraction of the nanoparticles were selected as 0.1, 200, and 0.2, respectively. Effects of parameters such as Reynolds number, the material of the porous medium (conductivity and porosity), and material of nanofluids have been investigated in the...
A system dynamics model to evaluate the housing market response to vulnerability reduction promotion policies
, Article International Journal of Disaster Risk Reduction ; Volume 44 , April , 2020 ; Kashani, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Interventions such as seismic retrofits and reconstruction of vulnerable buildings can minimize the social and economic consequences of future earthquakes. Various policies can reduce the vulnerability of communities in the face of future earthquakes by enhancing the public risk perception and reducing the costs of interventions for the landlords. There is a need for appropriate tools that can characterize the dynamics of the housing market in response to these policies. The simulation model presented in this manuscript addresses this need. In this model, the decision of the tenants and landlords is characterized by utilizing prospect theory. The impact of candidate policy interventions on...
Assessment of vulnerability reduction policies: Integration of economic and cognitive models of decision-making
, Article Reliability Engineering and System Safety ; Volume 217 , 2022 ; 09518320 (ISSN) ; Kashani, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Earthquakes can cause significant damage to vulnerable residential buildings and cause irreversible adverse economic, social, and socioeconomic consequences. Implementing hazard mitigation policies can enhance homeowners' willingness to adopt hazard mitigation measures such as seismic retrofits or insurance. Several past studies have proposed models that aimed to explain individuals' hazard mitigation behavior. Despite their advantages, these decision-making models are subject to limitations. This manuscript proposes a new decision-making model that addresses the shortcomings of previous models. The proposed decision-making model is then incorporated at the core of an agent-based model to...
Numerical simulation of surfactant flooding in darcy scale flow
, Article Petroleum Science and Technology ; Vol. 32, Issue. 11 , 2014 , Pages 1365-1374 ; ISSN: 10916466 ; Foroughi, S ; Beiranvand, M. S ; Sharif University of Technology
2014
Abstract
One of the methods that is used nowadays in enhanced oil recovery is surfactant flooding. The main mechanisms of surfactant flooding in reservoir consist of reduction of interfacial tension between water and oil and modification of rock wettability. In this study, the authors simulate the surfactant injection process in Darcy scale and in one-dimensional, multicomponent, multiphase state, and effects of physical phenomena such as adsorption, dispersion, convection, and exchange between fluids and solids are considered. Wettability alteration of reservoir rock due to presence of surfactant in injected fluid is detected in relative permeability and capillary pressure curves. First, the authors...
An agent-based simulation model to evaluate the response to seismic retrofit promotion policies
, Article International Journal of Disaster Risk Reduction ; 2018 ; 22124209 (ISSN) ; Movahedi, A ; Morshedi, M. A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Building owners’ appropriate risk-mitigation decisions can minimize the social, economic, and socioeconomic consequences of earthquakes. Implementation of appropriate policies can increase the adoption of seismic retrofit measures through the modification of owners’ beliefs. Social interactions among owners can influence their response to the implemented policies. There is a need for appropriate tools that consider the social interactions among the owners and facilitate the evaluation of their response to seismic retrofit promotion policies. The agent-based simulation model in this manuscript addresses this need. The implementation of policies and interactions among agents can influence...
An agent-based simulation model to evaluate the response to seismic retrofit promotion policies
, Article International Journal of Disaster Risk Reduction ; Volume 33 , 2019 , Pages 181-195 ; 22124209 (ISSN) ; Movahedi, A ; Morshedi, M. A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Building owners’ appropriate risk-mitigation decisions can minimize the social, economic, and socioeconomic consequences of earthquakes. Implementation of appropriate policies can increase the adoption of seismic retrofit measures through the modification of owners’ beliefs. Social interactions among owners can influence their response to the implemented policies. There is a need for appropriate tools that consider the social interactions among the owners and facilitate the evaluation of their response to seismic retrofit promotion policies. The agent-based simulation model in this manuscript addresses this need. The implementation of policies and interactions among agents can influence...
Energy of Graphs
, Ph.D. Dissertation Sharif University of Technology ; Akbari, Saeid (Supervisor)
Abstract
Let G be a graph with adjacency matrix A and Δ be a diagonal matrix whose diagonal entries are the degree sequence of G. Then the matrices L = Δ− A and Q = Δ+A are called Laplacian matrix and signless Laplacian matrix of G, respectively. The eigenvalues of A, L, and Q are arranged decreasingly and denoted by λ1 ≥ · · · ≥ λn, μ1 ≥ · · · ≥ μn ≥ 0, and q1 ≥ · · · ≥ qn ≥ 0, respectively. The energy of a graph G is defined as E(G) :=
n
i=1
|λi|.
Furthermore, the incidence energy, the signed incidence energy, and the H¨uckel energy of G are
defined as
IE(G) :=
n
i=1
√
qi, LE(G) :=
n
i=1
√
μi, HE(G) :=
2
r
i=1 λi, n=...
n
i=1
|λi|.
Furthermore, the incidence energy, the signed incidence energy, and the H¨uckel energy of G are
defined as
IE(G) :=
n
i=1
√
qi, LE(G) :=
n
i=1
√
μi, HE(G) :=
2
r
i=1 λi, n=...
Crypted Traffic Classification
, M.Sc. Thesis Sharif University of Technology ; Jalili, Rasool (Supervisor)
Abstract
A traffic classifier maps each input stream into a pre-defined traffic class. If the traffic is encrypted using a protocol, such as SSL, or is protected using an encrypted tunnel, it's content would be hidden from the classifier, in which case the common traffic classification methods will be ineffective. Although common security mechanisms which provide information confidentiality to user can't hide all properties of messages, including length and time. Some of the newly presented methods of traffic classification utilize these properties and can actually classify messages without accessing their content. We will study such methods and their limitations in this thesis. Of all the encrypted...
Integrated Drilling Oprations Optimization
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeid (Supervisor)
Abstract
Drilling Operations constitute more than fifty percent of total costs of well construction operations. Due to this fact, optimization of drilling operations could have significant effect on decrease in total costs of well construction. It is mentioning worthy that there are a variety of parameters which affect drilling operations from the view point of optimization. In many cases several of those aforementioned parameters are contrary in nature. Thus obtaining an integrated approach to optimize the operation by considering these effects is necessity. The goal of this thesis is to investigate different influential parameters of drilling operation optimization and to develop computer-based...
Experimental Analysis of Injection and Reservoir Brine Compatibility to Prevent Scale Formation during Various Oil and Gas Production Processes
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeid (Supervisor)
Abstract
Scale formation is an unpleasant phenomenon that occurs when the mixed fluids are incompatible. The scales damage the reservoir, wellbore and the surface facilities. They reduce the effective fluid path and increase the pressure drop of the system; so it is necessary to study the precipitation thermodynamics of scale formation, and present a trustable method for banning the scales from precipitation. In this project, it has been tried to study the value of precipitated scale due to the mixing of two incompatible waters (Civand and Sea Water). The results of which are compared with the results of a geochemical software named PHREEQC. Then, the performance of hydro chloridric acid as a scale...
Simulation of Drilling Fluid Movement Using Neural Network Modeling and Comparison with CFD Methods
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saeid (Supervisor)
Abstract
We report on numerical and intelligent modeling of three-dimensional laminar flow of non-Newtonian fluids driven by axial pressure gradient in annular media consisting of a coaxially rotating inner cylinder. This is an example of a rotating Couette flow with vast applications in food, oil and gas, and chemical engineering industries. We study the dynamics of pressure in and the velocities (in three directions X, Y and Z) of every grid in presence of rotation and without that by means of CFD. Afterward, we develop a novel predictive model based on an Artificial Neural Network (ANN). The hybrid ANN framework is trained and tested by over 100000 data which collected by CFD. We then perform...
The simulation of microbial enhanced oil recovery by using a two-layer perceptron neural network
, Article Petroleum Science and Technology ; Vol. 32, Issue. 22 , 2014 , pp. 2700-2707 ; ISSN: 10916466 ; Torkaman, M ; Sedaghat, M. H ; Ghazanfari M.H ; Sharif University of Technology
2014
Abstract
The authors simulated a reservoir by using two-layer perceptron. Indeed a model was developed to simulate the increase in oil recovery caused by bacteria injection into an oil reservoir. This model was affected by reservoir temperature and amount of water injected into the reservoir for enhancing oil recovery. Comparing experimental and simulation results and also the erratic trend of data show that the neural networks have modeled this system properly. Considering the effects of nonlinear factors and their erratic and unknown impacts on recovered oil, the perceptron neural network can develop a proper model for oil recovery factor in various conditions. The neural networks have not been...
Design and Fabrication of Drug-loaded Nanoparticles to Prevent Fibrillation of Alpha-synuclein in Parkinson
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor) ; Morshedi, Dina (Supervisor)
Abstract
The purpose of this study is to assess the inhibitory effects of an appropriate nanoparticles loaded with gallic acid on the fibrillation of alpha-synuclein. Alpha-synuclein is a major component of protein plaques in synucleinopathies, particularly Parkinson’s disease. Gallic acid (GA, 3,4,5-trihydroxy benzoic acid) is a well–known small molecule which can inhibit the formation of α-synuclein fibrils. For the process of fibrillation, purified protein was incubated at 37◦C and pH 7.2. Fibrillation was analyzed by the standard fibril methods.after that investigated fabricating of gallic acid trapped in the chitosan nanoparticles and gallic acid loaded in chitosan –coated mesoporous silica...
Designing an Efficient Algorithm for Group Recommender Systems based
on Group Profile
,
M.Sc. Thesis
Sharif University of Technology
;
Movaghar Rahimabadi, Ali
(Supervisor)
Abstract
Recommender Systems have become an attractive field within the recent decade since they facilitate users’ selection process in limited time. Conventional recommender systems have proposed numerous methods with a focus on recommending to individual users. Recently, due to a significant increase in the number of users, studies in this field have shifted to properly identify groups of people with similar preferences and provide a list of recommendations for each group. Because, offering a recommendations list to each individual undergoes computational cost and sometimes is not possible. So far, most of the previous studies requires the restrictive assumptions such as: (1) limited number of...
Seismic Performance Evaluation of Two New Steel Connections
, M.Sc. Thesis Sharif University of Technology ; Maleki, Shervin (Supervisor)
Abstract
In this research a novel steel connection, named “Doubly Reduced Beam Section”, and a new design procedure for “Reduced Flange Plate (RFP)“ connection are introduced and their seismic performance under cylcic loading is assessed. In order to avoid repetition of calculations, reducing human error and time consumption a computer design file in Microsoft Excel Program has been developed. Then along side the evaluation of the cyclic behavior of the connections utilizing the Finite Element Method (FEM analysis), a parametric study of the influence of various parameters on the connections seismic behavior is carried out. The results show that, following the limitations and guidelines stated in...
Automatic Concept Extraction to Improve the Recognition Performance for Sequential Patterns
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeid (Supervisor)
Abstract
In this dissertation, we introduced a Fuzzy based representation and comparison method for sequential patterns such as speech and online handwriting. The new model, called Fuzzy Elastic Matching Machine (FEMM), is simpler than traditional HMM based approaches and is not based on the common statistical assumptions of HMM systems. The model was tested on isolated word and phoneme recognition tasks in speech recognition domain and isolated letter recognition in Persian handwriting recognition. We showed that this method is faster than traditional HMM based models and more robust to noise. To train the model, we introduced a Symbiogenesis-based evolutionary training algorithm. This algorithm...
Design and Construction of Autonomous Underwater Vehicles
, M.Sc. Thesis Sharif University of Technology ; Seif, Mohammad Saeid (Supervisor)
Abstract
In recent years, unmanned vehicles have intensively been developed to reduce human dangers for marine applications. Predicting the hydrodynamic coefficients of an autonomous underwater vehicle is important during the vehicle’s design phase. In other words to design an AUV, one must clarify its maneuverability and controllability based on a mathematical model. The mathematical model contains various hydrodynamic forces and moments expressed collectively in terms of hydrodynamic coefficients. Therefore, the correct values of the coefficients must be known to precisely design the controller of AUVs.SUT-2 is an AUV, being developed by Marine Engineering Laboratory of Sharif University of...
Sliding Contact Problem of a Round Wedge with a FGM Coated Substrate with Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Adib Nazari, Saeid (Supervisor)
Abstract
Most of the current application and potential FGM included in the areas related to contact mechanic .These issues essentially are related to the transfer of force between two objects, that in general is with friction, so in this study the contact under the loading of horizontal and vertical with its different aspect such as the effect of contact region, the effect of round and also the effect of getting harden and soften of FGM.
The used method is a numerical method ¬(finite element method) that will resulted in contact equation discretisce by use of Penalty method. In this thesis is also presented the needed algorithms for solving the problem and the finite element code for solving the...
The used method is a numerical method ¬(finite element method) that will resulted in contact equation discretisce by use of Penalty method. In this thesis is also presented the needed algorithms for solving the problem and the finite element code for solving the...
Thermal Fatigue Investigation of Different Geometrical Aspect of via in Integrated Circuits
, M.Sc. Thesis Sharif University of Technology ; Adib Nazari, Saeid (Supervisor)
Abstract
The reliability of integrated circuits (IC) is related to material imperfections such as holes, cavities, cracks and etc. which occur in the manufacturing process. The operational conditions of IC create thermal stresses. These thermal stresses increase the chance of failure by making the imperfections critical in IC’s components such as VIA that is used as connection between interconnects in the multilevel integrated circuits. As a result, thermal fatigue needs to be investigated in VIA thoroughly.
The thermal stresses in VIA increase the possibility of hole forming due to hydrostatic stresses during manufacturing process and the amplitude of applied stresses under the operational...
The thermal stresses in VIA increase the possibility of hole forming due to hydrostatic stresses during manufacturing process and the amplitude of applied stresses under the operational...
Elastic Contact Analysis of Two Symmetrical Punchs With a Half Plane in a Quasi-Static Condition Using Finite Element Method
,
M.Sc. Thesis
Sharif University of Technology
;
Adib Nazari, Saeid
(Supervisor)
Abstract
Nowadays, the use of finite element Software applications in enigineering departments has become Inevitable and commonplace. Acceptance of the necessity of using such software applications for reducing the cost of research and development does not require any evidences of financial instruments to be presented. Reducing design and manufacture time together with pseudo-empirical approach has cuased the finite element science to become a conventional designing tools.
Since contact is the main method to apply a load on a ductile object,and stress concentration caused thereby is often a major cause of failure in mechanical parts, the issue of contact is a fundamental topic in mechanics of...
Since contact is the main method to apply a load on a ductile object,and stress concentration caused thereby is often a major cause of failure in mechanical parts, the issue of contact is a fundamental topic in mechanics of...