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Polymer-Enhanced low-salinity brine to control in situ mixing and salt dispersion in low-salinity waterflooding
, Article Energy and Fuels ; Volume 35, Issue 13 , 2021 , Pages 10540-10550 ; 08870624 (ISSN) ; Rostami, B ; Mahani, H ; Sharif University of Technology
American Chemical Society
2021
Abstract
Although viability of low-salinity waterflooding (LSWF) at the laboratory scale has been proven, there are some challenges associated with its field application, which sheds uncertainties on its economic success. One of the challenges is the minimum required volume of low-salinity water, which should be injected to the reservoir due to the salt dispersion in porous media. Once the low-saline brine is injected into the reservoir, mixing of injected (low-salinity) and resident (high-salinity) brines occurs and the developed mixing zone grows continuously as the front moves from the injection well toward the production well. Increase in the salinity of the front reduces the efficiency of LSWF....
Impact of injection parameters on mixing control by polymer-enhanced low-salinity waterflooding
, Article Energy and Fuels ; Volume 36, Issue 19 , 2022 , Pages 11808-11816 ; 08870624 (ISSN) ; Rostami, B ; Mahani, H ; Sharif University of Technology
American Chemical Society
2022
Abstract
In situ mixing by dispersive transport of salt and viscous fingering between the injected low-salinity (LS) brine and high-salinity (HS) formation brine can jeopardize the performance of low-salinity waterflooding (LSWF). In our previous papers, we demonstrated that in situ mixing can be suppressed by polymer-enhanced low-salinity waterflooding (PELS), in which a small amount of a viscosifying agent, such as a polymer, is added to the LS stream. Nevertheless, effective mixing control with PELS depends upon several factors and operational conditions, which have not yet been addressed. Therefore, this research focuses on the investigation of the impact of injection parameters, such as the...
The Effect of Metal Oxides on Gasochromic Properties of WO3 Thin Films Formed by Pulsed Laser Deposition
, M.Sc. Thesis Sharif University of Technology ; Mahdavi, Mohammad (Supervisor)
Abstract
Physical and chemical properties of tungsten oxide thin films change reversibly while exposure to hydrogen gas. This property is called gasochromic. To enhance optical properties of such films, nanostructured, amorphous and porous thin films of (WO3)1-x(MeO)x (MeO= TiO2, MoO3, NiO; x=0.09, 0.17, 0.23, 0.29, 0.33) were fabricated by Pulsed Laser Deposition. Molar percentage of Me/W (Me= Ti, Mo and Ni) was changed in films with respect to targets; for Ti and Ni always a reduction, but for Mo an enhancement for low percentages was observed. The reason is the existence of thermal ablation mechanism during deposition, in the other word is different vapor pressure effect. An increment in x for...
Spectral Theory of Signed Graphs and Digraphs
, Ph.D. Dissertation Sharif University of Technology ; Akbari, Saieed (Supervisor)
Abstract
A signed graph is a pair like (G; ), where G is the underlying graph and : E(G) ! f1; +1g is a sign function on the edges of G. Here, we study the spectral determination problem for signed n-cycles (Cn; ) with respect to the adjacency spectrum and the Laplacian spectrum. In particular we prove that signed odd cycles and unbalanced even cycles are uniquely determined by their Laplacian spectrums, but balanced even cycles are not, and we find all L-cospectral mates for them. Moreover, signed odd cycles are uniquely determined by their spectrums but the signed even cycles, (except (C4;) and (C4; +)), are not and we find almost all cospectral mates for them. A mixed graph is obtained from a...
Stress Analysis of in Cross-ply Laminates in Bending
, M.Sc. Thesis Sharif University of Technology ; Nosier, Asghar (Supervisor)
Abstract
In the present study, an analytical solution is developed to calculate the interlaminar stresses in long generally cross-ply laminated composite plates subjected to bending. At first, upon the integration of the strain-displacement relations and using the existing patterns in deformation of the long laminate, the general displacement field is extracted and simplified to the final form. Presented solution is based on a combined method containing the equivalent single-layer (ESL) theories beside the Reddy’s layerwise theory. In this method, the equivalent single-layer theories are utilized because of their simplicity and low computational efforts rather than the layerwise theory in evaluation...
An Investigation on the Microstructure and Mechanical Properties of Almg6 Alloy-Carbon Nanotube Composite Produced by Accumulated Roll Bonding Process
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
In recent years, the use of high specific strength aluminum alloys in automotive and aerospace industries is in progress due to their energy savings. On the other hand, the carbon nanotubes (CNTs), due to their ultra-high strength and modulus of elasticity, have been considered as an excellent reinforcement for the metal matrix composites used in these industries. For production of these materials, the severe plastic deformation (SPD) has been known as a method of grain refinement to increase the strength and ductility. In this research, the composites of AlMg6 reinforced with CNT were produced by accumulated roll bonding (ARB) known as a SPD technique and their properties were compared...
Smart water flooding performance in carbonate reservoirs: an experimental approach for tertiary oil recovery
, Article Journal of Petroleum Exploration and Production Technology ; Volume 9, Issue 4 , 2019 , Pages 2643-2657 ; 21900558 (ISSN) ; Ayatollahi, S ; Bahari Moghaddam, M ; Sharif University of Technology
Springer
2019
Abstract
Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions...
Distribution System Planning Considering Demand Response Programs
, M.Sc. Thesis Sharif University of Technology ; Fotuhi Firuzabad, Mahmud (Supervisor)
Abstract
Nowadays, moving toward new technologies and smart grids is a successful way to prevail over distribution system challenges. In the presence of smart grids, demand-side management (DSM) is capable to affect the expansion of network resources. An effective DSM tool is demand response (DR). In this thesis, distribution system planning (DSP) considering DR is presented and the effects of DR on DSP are investigated. This thesis proposes direct load control (DLC) DR which is an incentive-based program (IBP) where a utility offers financial incentives to the customers to control their consumption through installing smart meters and switches. The utility deploys the DR program to reduce network...
Experimental Investigation of Long time Behavior of Interfacial Waves in a Two Layer Immiscible Fluid
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosadegh (Supervisor)
Abstract
The motion of a surface wave in a two-layer fluid can lead to generation of sub-harmonic interfacial waves through a nonlinear resonant interaction mechanism. The interfacial waves grow exponentially in time until they reach a maximum amplitude and then oscillate down to a final amplitude, referred to as ultimate amplitude, in long term. This may lead to considerable mixing of the layers in miscible fluid and increase the thickness of the diffuse layer. Experiments show that the diffuse layer causes frequency shift and decreases the ultimate amplitude. In this study, long time behavior of interfacial waves in a two layer immiscible fluid was investigated. A two-layer immiscible system...
Effect of Fe-Containing supports prepared by a novel sol–gel method in the co methanation reaction: co elimination and synthetic natural gas production
, Article Energy Technology ; Volume 7, Issue 10 , 2019 ; 21944288 (ISSN) ; Rezaei, M ; Nematollahi, B ; Baghalha, M ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
Herein, the CO methanation reaction is studied over Ni/Fe–Al mixed oxides with various Fe and Al contents. The mesoporous nanocrystalline supports are prepared by a novel sol–gel process using propylene oxide as a gelation agent. The deposition–precipitation method is used for the deposition of nickel on the catalyst support. The samples are characterized by Brunauer–Emmett–Teller (BET), X-ray diffractometry (XRD), temperature programmed reduction (TPR), temperature programmed oxidation (TPO), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicate that increasing the iron content and reducing the Al percentage in the catalyst support reduces the...
Preparation of Ni/MeAl2O4-MgAl2O4 (Me=Fe, Co, Ni, Cu, Zn, Mg) nanocatalysts for the syngas production via combined dry reforming and partial oxidation of methane
, Article Renewable Energy ; Volume 149 , April , 2020 , Pages 1053-1067 ; Rezaei, M ; Nematollahi, B ; Baghalha, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this paper, a comprehensive study was conducted on the application of various MeAl2O4 spinels (Me = Fe, Co, Ni, Cu, Zn, Mg) as the catalyst support for the preparation of nickel-based catalysts in the combined dry reforming and partial oxidation. These supports were synthesized by a novel facile sol-gel method using propylene oxide as the gelation agent and nickel was deposited on these supports by the deposition-precipitation method. The prepared samples were characterized by N2 adsorption/desorption, XRD, TPR, TPO, CO2-TPD, SEM, and TEM techniques. In addition, the temperature-programmed methane dissociation (TPMD) was performed to evaluate the effect of nickel-support interaction on...
P Fister’s Local-Global Principle
, M.Sc. Thesis Sharif University of Technology ; Gholamzadeh Mahmoudi, Mohammad (Supervisor)
Abstract
This master’s thesis has two major parts. The first part which includes chapters 1 to 8, describes the article A. Pfister, Quadratische Formen in beliebigen Körpern, Invent. Math. 1, (1966)pp. 116-132, and expresses important facts about the Witt ring W(K) of quadratic forms over an arbitrary field K of characteristic unequal to 2. Among those, it is shown that the order of each element in the additive group of W(K) is a power of 2, the Witt ring doesn’t have any zero divisor of odd dimension and a necessary and sufficient condition for W(K) to be an integral domain is given. The connections between the square class number of a field and the cardinality of its Witt ring and, providing some...
An evaluation of wind turbine waste heat recovery using organic Rankine cycle
, Article Journal of Cleaner Production ; Volume 214 , 2019 , Pages 705-716 ; 09596526 (ISSN) ; Hajabdollahi, Z ; Hoghooghi, H ; Kim, K. C ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Wind turbine size has increased to megawatt capacity, and the related technologies and facilities have improved, including the cooling systems. Currently, all of the heat generated by wind turbine components is wasted to the environment. This study presents a conceptual design of a novel method for waste heat recovery of a wind turbine using an organic Rankine cycle (ORC). An organic Rankine cycle is implemented to the wind turbine as a part of the cooling system. The proposed system is thermodynamically modeled to evaluate the amount of recovered energy. Seven working fluids are chosen and investigated in the simulations to estimate the working fluid effect. The results revealed that the...
An experimental and computational study on the rate constant of electrochemically generated N-acetyl-p- quinoneimine with dimethylamine
, Article International Journal of Electrochemical Science ; Volume 3, Issue 10 , 2008 , Pages 1092-1107 ; 14523981 (ISSN) ; Haqgu, M ; Nematollahi, D ; Gholami, R. M ; Sharif University of Technology
2008
Abstract
Electrochemical oxidation of acetaminophen (N-acetyl-p-aminophenol) (1) has been studied in the presence of dimethylamine (2) as a nucleophile in aqueous solution, by means of cyclic voltammetry and controlled-potential coulometry. The results indicate the participation of electrochemically generated N-acetyl-p-quinoneimine (1a) in Michael reaction with dimethylamine (2). Based on ECE mechanism, the observed homogeneous rate constant (kobs) of the above mentioned reaction is estimated by comparing the experimental cyclic voltammograms with the digital simulated results. Further more; kinetics and mechanism of the reaction were studied with ab initio calculation, Monte Carlo and QM/MM...
Spinel MgAl2O4 nanospheres coupled with modified graphitic carbon nitride nanosheets as an efficient Z-scheme photocatalyst for photodegradation of organic contaminants
, Article Applied Surface Science ; Volume 585 , 2022 ; 01694332 (ISSN) ; Kazemeini, M ; Sadjadi, S ; Nematollahi, R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this contribution, spinel MgAl2O4 nanospheres prepared by the combustion method were coupled with thermally-exfoliated g-C3N4 nanosheets (TE-GCN) through an efficient isoelectric point-assisted calcination technique. Physical characteristics of the synthesized nanocomposite were understudied utilizing the XRD, FT-IR, FE-SEM, TEM, BET-BJH, UV–Vis DRS, PL, and EIS analyses. This material was used as a novel nano-photocatalyst for degradation of reactive red 195 (RR195) industrial dye contaminant. Results revealed that, a successful synthesis of a heterojunction between the components of the nanocomposite was achieved. This exhibited an enormously improved electron-hole separation leading to...
Probabilistic Assessment of Flood Risk Using Data-Driven Flood Depth Modeling: A Case Study of Poldokhtar City
, M.Sc. Thesis Sharif University of Technology ; Safaie Nematollahi, Ammar (Supervisor)
Abstract
The present study aims to evaluate the flood risk of Poldokhtar city probabilistically using Monte Carlo Simulations (MCS). Two-dimensional (2D) models, which are highly accurate, have been used widely for flood modeling. However, they are not suitable for applications such as MCSs that need to be repeated many times or real-time flood forecasting applications, which require that flood inundation maps quickly be produced. In the current study, we developed a data-driven surrogate model based on the Least Squares Support Vector Machine (LS-SVM), a supervised machine learning method, to predict flood depth in order to simulate similar results to 2D hydraulic modeling. HEC-RAS was used for 2D...
Spectrum Sharing Optimization in Cognitive Radio Networks
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohammad Afshin (Supervisor)
Abstract
The dream of increasing in service quality and channel capacity in wireless networks is severely limited by the scarcity of energy and bandwidth, which are the two fundamental resources for communications. New communications and networking paradigms such as cognitive radio networks emerged in recent years that can intelligently and efficiently utilize these scarce resources. Although cognitive users are able to make intelligent decisions on spectrum usage and communication parameters based on the sensed spectrum dynamics and other users' decisions, different network users typically belong to different operators and may pursue different goals, so fully cooperative behaviors cannot be...
Neda: supporting direct inter-core neighbor data exchange in GPUs
, Article IEEE Computer Architecture Letters ; Volume 17, Issue 2 , 2018 , Pages 225-229 ; 15566056 (ISSN) ; Sadrosadati, M ; Falahati, H ; Barkhordar, M ; Sarbazi Azad, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Image processing applications employ various filters for several purposes, such as enhancing the images and extracting the features. Recent studies show that filters in image processing applications take a substantial amount of the execution time, and it is crucial to boost their performance to improve the overall performance of the image processing applications. Image processing filters require a significant amount of data sharing among threads which are in charge of filtering neighbor pixels. Graphics Processing Units (GPUs) attempt to satisfy the demand of data sharing by providing the scratch-pad memory, shuffle instructions, and on-chip caches. However, we observe that these mechanisms...
Hydraulic Assessment of Seismic Resilience of Urban Water Supply Network
, M.Sc. Thesis Sharif University of Technology ; Safaie Nematollahi, Ammar (Supervisor) ; Mahsuli, Mojtaba (Co-Supervisor)
Abstract
The purpose of this study is to investigate the resilience of the urban water supply network against earthquakes, A hydraulic analysis of the water supply network was implemented in Rtx software to study the effective parameters in the resilience of the network. Rtx software is a tool for assessing the reliability and resilience of communities and infrastructure to natural hazards by taking into account related uncertainties. The water supply network, like other networks, is affected by earthquakes. The seismic damage varies depending on the vulnerability of the network, the intensity of the earthquake, the focal depth, and the distance from the epicenter. Thus, it reduces the ability of the...
Bilateral Control of a Master-Slave Robotic System for Large-Organ Grasping with Haptic Feedback
, M.Sc. Thesis Sharif University of Technology ; Farahmand, Farzam (Supervisor) ; Behzadipour, Saeed (Co-Advisor)
Abstract
The age of minimally invasive surgery has brought forth astounding changes in the health care field. Less pain and quicker patient recovery have been demonstrated with several types of operations that were once performed by an open technique. With these changes have come reports of complications. The decreased sense of touch is just one of several limitations inherent to current techniques of minimally invasive surgery that limit detection of subtle or unapparent lesions on palpation, such as common duct stones and liver lesions. The purpose of this study is to design and implement a bilateral control on a master-slave robotic system for grasping large ogans and demonstrate the ability of a...