Loading...
Search for:
shojaei--mohammad-reza
0.199 seconds
Total 6134 records
History Matching using Streamline Simulation
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor) ; Badakhshan, Amir (Supervisor) ; Kamali, Mohammad Reza (Supervisor)
Abstract
Management decisions, Enhanced Oil Recovery, and reservoir development plans in petroleum industries are based on predictions by reservoir simulation. Due to uncertainties in model parameters or engineering assumptions, the simulation results are not accurate, while they are correct. One remedy is to match simulation results with engineering measurements, typically pressure and flow rate, by adjusting model parameters. In Reservoir Engineering literature, this is called History Matching and is an optimization problem. Common methods of history matching are based on finite difference simulation, and therefore have a very low speed. In addition, these methods usually ignore Geostatistical...
Investigating the nodulation mechanism of copper cathode based on microscopic approach: As a punch failure factor
, Article Engineering Failure Analysis ; Volume 133 , 2022 ; 13506307 (ISSN) ; Reza Khayati, G ; Mohammad Javad Korasani, S ; Kafi Harnashki, R ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The presence of nodules on the surface of cathode copper plates was the most important reason for the failure of the punch of mechanical clinching of copper cathode sheets. This study demonstrated a comprehensive investigation into the nodulation growth of copper cathodes in the electrorefining plant based on metallographic analysis. More than 15 random samples were selected from the top, middle, and bottom of the cathodes produced in the Khatoon Abad copper refinery, Iran. Studies were carried out based on the determination of growth modes including field oriented isolated crystal (FT), basis-oriented reproduction (BR), field-oriented texture (FT), and unoriented dispersion (UD). A scanning...
Simulation of three-dimensional flow in compression resin transfer molding by the control volume/finite element method
, Article Composites Technologies For 2020 ; 2004 , Pages 357-362 ; 9781855738317 (ISBN) ; Boorboor, D ; Reza Ghaffarian, S ; Sharif University of Technology
Woodhead Publishing Limited
2004
Abstract
In compression resin transfer molding (CRTM), resin injection and mold closing occur during the mold filling stage. In this paper, numerical simulation of threedimensional flow in compression resin transfer molding (CRTM) is presented. Numerical method is based on the control volume/finite element method (CVFEM) and the numerical algorithm to update the flow front at each time step is based on quasi-steady state approach. Numerical scheme presented in this article can be used to predict the flow progression, pressure distribution, mold clamping force in full threedimensional mold. Numerical example provided in the paper demonstrates the effectiveness of the developed numerical simulation in...
The Study of Noncovalent Interactions in Several Rhenium Tricarbonyl Complexes Bearing Nitrogen Containing Ligands
, M.Sc. Thesis Sharif University of Technology ; Kia, Reza (Supervisor)
Abstract
In this study, synthesis structural and theoretical studies of four rhenium tricarbonyl complexes with 3-cyanobenzaldimino ethylenediamine (3CNbzen) and 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenantherene (Ph4TAP) were investigated. The synthesized complexes were characterized by spectroscopic methods and their solid-state structure were determined by single-crystal X-ray diffraction analysis. Using single-crystal X-ray diffraction structure, the intra- and intermolecular interactions of the complexes and their dimers resulted from X-ray Cartesian coordinates were investigated. Furthermore, computational approaches were carried out to confirm the existence of the intra- and intermolecular...
A misbehavior‐tolerant multipath routing protocol for wireless Ad hoc networks [electronic resource]
, Article International Journal of Research in Wireless Systems (IJRWS) ; Vol. 2, Issue 9, pp. , Sep. 2013 ; Pakravan, Mohammad Reza ; Aref, Mohammad Reza ; Sharif University of Technology
Abstract
Secure routing is a major key to service maintenance in ad hoc networks. Ad hoc nature exposes the network to several types of node misbehavior or attacks. As a result of the resource limitations in such networks nodes may have a tendency to behave selfishly. Selfish behavior can have drastic impacts on network performance. We have proposed a Misbehavior-Tolerant Multipath Routing protocol (MTMR) which detects and punishes all types of misbehavior such as selfish behavior, wormhole, sinkhole and grey-hole attacks. The protocol utilizes a proactive approach to enforce cooperation. In addition, it uses a novel data redirection method to mitigate the impact of node misbehavior on network...
Synthesis and Characterization of Nanodiamond/Epoxy Nanocomposites
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Bagheri, Reza (Co-Advisor)
Abstract
In recent years, it has been interesting to to use nanodiamond (ND) in oreder to improve mechanical and electrical properties. Producing it in very low dimensions, make it more important to treat ND surface proportional to its application. Hence, with knowledge of influence of ND and its functional groups on curing process, in present research,carboxylic acid and amine were settled on its surface and in addition to untreated ND, they were dispersed in DGEBA epoxy as a reinforcement. Afterward, by adding triethylenetetramine kinetic cure of nanocomposites were investigated. For this purpose, conversion was determined using heat flow of reaction and then activation energy was calculated....
Investigation of the Effective Parameters on the Morphological and Mechanical Properties of Polyamide 6/Rubber/Carbon Nano Tube Nanocomposites Prepared by Melt Mixing
, Ph.D. Dissertation Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
Preparation of binary polyamide 6 (PA6) / carbon nano tube (CNT) and ternary PA6 / EPR-g-MA / CNT has been carried out using melt mixing. Four PA6s were selected with different viscosities (and molecular weights) and molecular structures (linear or branched). Effect of CNT content (up to 2 wt%) and mechanical mixing conditions (rotor speed, temperature and time of mixing) have been investigated. Ethylene- propylene rubber grafted maleic anhydride (EPR-g-MA) was selected at 20 wt% as toughening agent for ternary nanocomposites and mixing sequence of PA6 , EPR-g-MA and CNT has been investigated. Morphological observations showed that dispersion of CNT is done by erosion mechanism at low melt...
Impermeability of Oxygen in Passive/Active Polyethylene Nanocomposite Films
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
In this study, polyethylene films made of LDPE / LLPE / reinforced with mechanical barrier of clay and reactant of iron nanoparticles were made in their optimal combination and necessary improvements were made on them. Investigations show that, independent of volume fraction, the addition of spherical nanoparticles does not have much effect on reducing the polymer matrix’s permeability. In nanocomposites containing cylindrical particles, for considerable reduction of the permeability, over 20 volume percent of nanoparticles it is required, while in platelet nanoparticles, less than 10% vol is sufficient. In clays with modifier concentration above the cation exchange capacity, there is less...
Preparation and Characterization of Unsaturated Polyester Resin/Nanodiamond Nanocomposites
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
In recent decades, nano-structured materials have been allocated specific position for wide use in various fields. The nano-diamonds has attracted the attention of many researchers. The inherent characteristics of a diamond like spherical structure of nanoparticles and carbon atoms which have used their full capacity in the chemical bonds,also the same surface as the radiography particles which have empty orbital, provides an ability to perform a variety of surface modification on the particle . This article introduces the nanocomposites based on polymer, constituents specification and discuss properties of nanocomposites after mixing components together. Lots of studies was on...
Experimental Study of Formation Damage Reduction during Drilling of Horizontal Wells Using Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
One the basic challenges during drilling of both vertical and horizontal wellbores is due to mud filtrate invasion into the formation. Addition of nanoparticles to composition of drilling fluid has been recognized as a measure of control and reduction of filtrate invasion. Despite notable advances in formulation of nano-enhanced drilling fluids, effects of surface wettability of nanoparticles on their performance have not been studied with any precision. Moreover, return permeability of a grain packed porous media after extreme invasion by mud filtrate has not been experimentally measured in a radial system, yet. The last but not least, Generation and development of mud cake opposite the...
Investigation of the Effect Recycled Nanosilica from Battery Separator by Pyrolysis Method on Mechanical Properties and Adhesion between Rubber and Steel
, M.Sc. Thesis Sharif University of Technology ; Pircheraghi, Gholamreza (Supervisor)
Abstract
Creating sustainable development in today's human societies is essential, one of the pillars of achieving this important goal is environmental protection. Thus, waste management as a new challenge is leading engineers. Lead-acid battery waste is one of the sources of environmental pollution. Lead-acid battery separators contain 50% recyclable nanosilica. The main challenge of recycling nanosilica from separators is the presence of significant amounts of 6 to 9% wt.% of lead and 5% by weight of other impurities. Therefore, in the present study, lead trapped in the separating pores is removed using mechanical washing or abrasive washing. Then, the quality of recycled nanosilica is evaluated...
Study of Mechanical Properties of PP/r-PET Composite Reinforced with Flax Fiber
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
Recycling of polymers, with the aim of environmental protection and economical benefits, is important procedure, which is constantly developing. In this study the effect of the incorporation of recycled PET(r-PET) and recycled polypropylene/Flax(r-PP/Flax) to PP at low (20wt %) and medium content (40wt %) of r-PET was investigated. Polymer compounds were prepared by twin screw extruder followed by injection moulding. The effect of r-PP/Flax and r-PET on PP was evaluated using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetery (DSC), rheological behavior, and mechanical properties (tensile modulus, yield strength, and charpy notched impact...
An Investigation on the Effect of Carbon Nanotubes on Physical and Mechanical Properties of Elastomers
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Nanostructure matrials have reached a special place to be used in wide applications in recent decades. Among those carbon nanotubes have got much attention due to their excellent mechanical and electrical properties and their ability of developing new nanocomposites, though the issues of perfect dispersion and interaction with polymeric matrix hinders their development. In this work, recent advances on carbon nanotubes (CNTs) and rubbers nanocomposites have been reviewed and the intrinsic potential of carbon nanotubes as reinforcing filler in elastomeric materials has been demonstrated. In experimental section in addition to CNTs, two different grades of CBs, i.e. N330 and super conductive...
Flow Control in Vacuum Assisted Resin Transfer Molding
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
Vacuum assisted resin transfer molding (VARTM) is one of the most efficient and low cost process in composite industries. In this process, the preform is covered by a flexible vacuum bag and resin flows into the mold with applying vacuum pressure at the vent. The main objective in VARTM process is preventing voids and dry spots formation in final composite part because these defects may significantly deteriorate the mechanical properties of a structure. Flow front is an important parameter in this process which have a high influence on the void formation. Resin flow control is required to prevent dry spots or micro voids during the VARTM process. In general, the flow control is classified...
Designing a Multi-Attribute Multi-Stage Risk-adjusted Control Chart
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Mohammad Taghi (Supervisor)
Abstract
Hospitals increasingly use control charts to monitor clinical processes and their outcomes. In medical context, control charts should have stable performance when different patients with different levels of risk enter the hospital. In order to monitor multi-attribute medical processes, we propose a new control chart with entities having different levels of risk. First, risk-adjusted multivariate cumulative sum control chart (RA-MCUSUM) is developed. Then, simulation experiences are performed to demonstrate the application and to evaluate RA-MCUSUM performance in terms of in-control average run length (ARL0) stability with the one of a standard MCUSUM chart.The results show that while the...
Ezafe Recognition Using Dependency Parsing
, M.Sc. Thesis Sharif University of Technology ; Bahrani, Mohammad (Supervisor) ; Shojaei, Razieh (Co-Supervisor)
Abstract
Ezafe is regarded as one of the most controversial and challenging issues in different Persian Language Processing (NLP) fields. It is recognized and pronounced but usually not written. So, this results in a high degree of ambiguity in Persian texts. Dependency grammar plays a significant role in optimization problems. So, to recognize the position of Ezafe in a sentence, this grammar is used in this current study. This method helps speed up computer operations and use low memory. Within this framework, first we take a close look at Ezafe distribution in Persian text. We use Uppsala Persian Dependency Corpus (2015) to analyze parsed sentences. The Ezafe constructions under study include...
Experimental and Modeling Study of Controlled Salinity Water Injection for Enhanced Oil Recovery from one of Iranial Oil Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor) ; Masihi, Mohsen (Co-Advisor)
Abstract
From previous years, water injection was considered as one of the most common methods for enhanced oil recovery. But recently much attention has been paid on the use of low salinity water (LSW) as an enhanced oil recovery fluid. The main mechanism that causes improve oil recovery is wettability alteration to a more water wet state. The change observed in recovery factor during LSW flooding induced from changes in relative permeability and capillary pressure when different levels of salinity are used. However, a few researchers tried to evaluate how macroscopic flow functions depend on the salinity of injected water. To this end, a series oil displacements by water performed on sandstone rock...
Analysis and Improvement of Intrusion Detection Methods in Data Network Routers
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Pakravan, Mohammad Reza (Co-Advisor)
Abstract
High-quality online services demand reliable and fast packet delivery at the network layer. However, clear evidence documents the existence of compromised routers in the ISP and enterprise networks, threatening network availability and reliability. A compromised router can stealthily drop, modify, inject, or delay packets in the forwarding path to launch Denial-of-Service, surveillance, man-in-the-middle attacks, etc. So researches tried to create intrusion detection methods to identify adversarial routers and switches. To this end, data-plane fault localization (FL) aims to identify faulty links and is an effective means of achieving high network availability. FL protocols use...
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Bagheri, Reza (Supervisor)
Abstract
Taghizadeh Manzari, M. (MehrdadThe main goals of this project are studding the effect of carbon nanotube on the properties of PA6/PA66 matrix and miscibility of PA6/PA66 blend. So PA6/PA66/CNT nanocomposites were compounded by melt mixing method and samples were prepared by injection molding. Due to study miscibility of PA6 and PA66, we used DMTA test and found that PA6 and PA66 are miscible because of existing one pick on DMTA graph. Also DSC test results confirmed that PA6 and PA66 are miscible. Moreover, according to DMTA results, modulus will be rose by increasing CNT content. Mechanical test showed same results in this case. Adding 1%CNT to matrix caused 10% improvement in modulus and...
Topological Defects in Confined Nematics by Planar Anchoring
, M.Sc. Thesis Sharif University of Technology ; Ejtehadi, Mohammad Reza (Supervisor) ; Mozaffari, Mohammad Reza (Supervisor)
Abstract
Confining nematic liquid crystal between two curved boundary conditions while the nematic molecules have a degenerate planar anchoring leads to complex and beautiful textures of molecular disparagement(defect) in the bulk and on the surfaces. Such the liquid crystal shells are made with double-emulsion techniques in microfluidic devices have provided applications for micro-scale colloidal linkers.In this work, we have numerically minimized the elastic energy in one-constant approximation in present of Fournier’s degenerate surface potential with finite element method. The nematic shell is confined between two spherical surfaces that we have studied the final energies and their related...