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Numerical Simulation and Enalysis of an Electrokinetically-driven Microdispenser
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Saeed (Supervisor) ; Shafiee, Mohammad Behshad (Supervisor)
Abstract
Nowadays Lab-on-a-chip systems are being widely used in medical applications, especially in analyzing minute volumes of blood for diagnosis and treatment of some crucial diaseses like diabetic. A Lab-on-a-chip is comprised of a variety of components such as micromixer, microdispenser, detection and separation units and so on. In this thesis, however, we have analyzed and numerically simulated a microdispenser which is electrokinetically driven. In other words, electrical potentials are applied to electrodes in order to conduct two fluids within a cross microchannel, and distribution of a sample fluid takes place due to appropriately applied potentials. In order to analyze and simulate the...
Dynamic Planning of Transmission Expansion
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hamid (Supervisor)
Abstract
Goal of this project is to present a method for dynamic transmission planning in restructured environment by system regulator. Congestion, fair competition in power market, stakeholders’ desires in transmission expansion, transmission investment traits, creating incentive for investment and transcos revenue are considered in this work. Presentation of methodology for reliability evaluation is necessary because of increasing uncertainties due to restructuring. Remedial action method is suggested for uncertainties analysis and reliability index presented for measuring degree of reliability. The method has been applied to the IEEE 14-bus system. ...
Damping Critical Electromechanical Oscillations in Power System Through Remedial Actions Using Wide Area Measurement System (WAMS)
, Ph.D. Dissertation Sharif University of Technology ; Parniani, Mostafa (Supervisor) ; Aminifar, Farrokh (Co-Supervisor)
Abstract
Nowadays, by proliferation the basis of the phasor-based synchronous wide area measurement system (WAMS), its application for improving electromechanical oscillations damping has been considered by researchers. In interconnected power systems, inter-area modes are usually critical modes. There are two approaches for damping these modes by utilizing WAMS: 1) the traditional approach of using power system stabilizers with wide area signals; and 2) discrete corrective actions by changing the operating conditions. The first approach requires a thorough study at the design stage, installation and testing. Besides, the controller is designed for a specific operating point. Nevertheless, in the...
Evaluation of dike-type causeway impacts on the flow and salinity regimes in Urmia Lake, Iran
, Article Journal of Great Lakes Research ; Volume 35, Issue 1 , 2009 , Pages 13-22 ; 03801330 (ISSN) ; Tofighi, M. A ; Vafaee, F ; Sharif University of Technology
2009
Abstract
Urmia Lake, located in a closed basin in north-west Iran, is the largest lake (5000-6000 km2) in the Middle East. It is very saline with total dissolved salts reaching 200 g/l compared with a normal seawater salinity of about 35 g/l. The construction of a causeway, which was initiated in 1979 but then abandoned until the early 2000s, is near completion and will provide road access between the western and eastern provinces. The causeway has an opening 1.25 km long and divides Urmia Lake into a northern and southern basin and restricts water exchange. The flow and salinity regimes are affected by the presence of this new causeway, and there are concerns over the well being of the Artemia...
Oxidized graphitic carbon nitride nanosheets as an effective adsorbent for organic dyes and tetracycline for water remediation
, Article Journal of Alloys and Compounds ; Volume 809 , 2019 ; 09258388 (ISSN) ; Villar Rodil, S ; Paredes, J. I ; Zaker Moshfegh, A. R ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Graphitic carbon nitride (g-C3N4) is promising as adsorbent for water remediation as its chemical structure allows a variety of mechanisms to interact with wastewater pollutants. However, several issues, such as low specific surface area and insufficient dispersibility in water, have to be tackled to achieve a competitive performance in such use. Previous attempts to improve the features of g-C3N4as an adsorbent have relied on carbon doping and exfoliation in the solid phase by thermal expansion. Here, we demonstrate that exfoliation in the liquid phase by a combination of oxidation and sonication allows preparing g–C3N4–based materials with improved dispersibility in water, increased...
Carbon nanotubes composite membrane for water desalination
, Article Advances in Science, Technology and Innovation ; 2021 , Pages 163-184 ; 25228714 (ISSN) ; Khadir, A ; Taghipour, M ; Sharif University of Technology
Springer Nature
2021
Abstract
The demand for freshwater has enormously risen the water stress in various parts of the globe. Accessibility of clean water is crucial for sustainable development involving socioeconomic and environmental promotion. Considering the fact that 96.5% of all Earth’s water is related to seawater, desalination (producing clean potable water from sea or saline water) can be considered as a leading solution to fulfill water scarcity problem. Among various advanced and conventional techniques, carbon nanotube (CNT) membrane has become an attractive alternate for most of water treatment methods owing supreme features such as easy operationality, low energy and expense requirement, high water...
Mechanism of surfactant in trichloroethene degradation in aqueous solution by sodium persulfate activated with chelated-Fe(II)
, Article Journal of Hazardous Materials ; Volume 407 , 2021 ; 03043894 (ISSN) ; Li, M ; Gu, X ; Danish, M ; Shan, A ; Ali, M ; Qiu, Z ; Sui, Q ; Lyu, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The mechanism of surfactants in surfactant-in situ chemical oxidation (S-ISCO) coupled process for trichloroethene (TCE) degradation was firstly reported. The performance of TCE solubilization and inhibition of TCE degradation in three nonionic surfactants (TW-80, Brij-35, TX-100) in PS/Fe(II)/citric acid (CA) system was compared and TW-80 was evaluated to be the optimal surfactant in S-ISCO coupled process due to the best TCE solubilizing ability and minimal inhibition for TCE degradation (only 31.8% TCE inhibition in the presence of 1 g L−1 TW-80 surfactant). The inhibition mechanism in TCE degradation was also demonstrated by comparing the strength of ROSs and PS utilization. In the...
Enhanced trichloroethene degradation performance in innovative nanoscale CaO2 coupled with bisulfite system and mechanism investigation
, Article Separation and Purification Technology ; Volume 278 , 2022 ; 13835866 (ISSN) ; Sun, X ; Ali, M ; Shan, A ; Idrees, A ; Yang, C ; Lyu, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The effect of bisulfite (HSO3–) in nCaO2/Fe(III)/HSO3– system on improving HO• generation and trichloroethene (TCE) removal was innovatively reported. The enhancement mechanism of HSO3– for TCE removal in nCaO2/Fe(III)/HSO3– system was caused not only by the complexing and reducing effects on promoting the conversion of Fe(III) to Fe(II), but also due to the reaction with O2 in water to produce SO4–• for accelerating TCE degradation. A double effect of nCaO2 as an oxidant source to generate HO• and as a O2 source to promote SO4–• generation was revealed. A pseudo-second-order kinetic model of TCE removal was determined and 94.6% TCE degradation was achieved within 60 min at the...
Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation
, Article Water Supply ; Volume 21, Issue 8 , 2021 , Pages 4429-4441 ; 16069749 (ISSN) ; Ali, M ; Cui, C ; Lyu, S ; Sharif University of Technology
IWA Publishing
2021
Abstract
The simultaneous oxidation performance of benzene, toluene, ethylbenzene, and xylene (BTEX) by nanoscale calcium peroxide particles (nCaO2) activated with ferric ions (Fe(III)) and the mechanism of the enhancement of BTEX degradation by L-cysteine (L-cys) were investigated. The batch experimental results showed that the nCaO2/Fe(III)/L-cys process was effective in the destruction of BTEX in both ultrapure water and actual groundwater. A proper amount of L-cys could enhance BTEX degradation due to the promotion of Fe(II)/Fe(III) redox cycles by the participation of L-cys, but an excessive presence of L-cys would cause inhibition. Adding 1.0 mM L-cys to the nCaO2/Fe(III) system, the...
Enhancement in reactivity via sulfidation of FeNi@BC for efficient removal of trichloroethylene: Insight mechanism and the role of reactive oxygen species
, Article Science of the Total Environment ; Volume 794 , 2021 ; 00489697 (ISSN) ; Idrees, A ; Zaman, W. Q ; Abbas, Z ; Farooq, U ; Ali, M ; Yang, R ; Zeng, G ; Danish, M ; Gu, X ; Lyu, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
A novel catalyst of sulfidated iron-nickel supported on biochar (S-FeNi@BC) was synthesized to activate persulfate (PS) for the removal of trichloroethylene (TCE). A number of techniques including XRD, SEM, TEM, FTIR, BET and EDS were employed to characterize S-FeNi@BC. The influence of sulfur to iron ratio (S/F) on TCE removal was investigated by batch experiments and a higher TCE removal (98.4%) was achieved at 0.22/1 ratio of S/F in the PS/S-FeNi@BC oxidation system. A dominant role in iron species conversion was noticed by the addition of sulfur in FeNi@BC system. Significant enhancement in recycling of the dissolved and surface Fe(II) was confirmed which contributed to the generation of...
Plasmon-enhanced photocatalytic activity in the visible range using AgNPs/polydopamine/graphitic carbon nitride nanocomposite
, Article Applied Surface Science ; Volume 585 , 2022 ; 01694332 (ISSN) ; Amirjani, A ; Reza Madaah Hosseini, H ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Developing an efficient visible-light-driven photocatalyst is believed to be a practical solution for clean energy and environmental remediation. The present study aimed to broaden current knowledge of the graphitic carbon nitride (g-C3N4)-based plasmonic photocatalysts by decorating polydopamine-grafted g-C3N4 (PDA/g-C3N4) with silver nanoparticles (AgNPs). The nanocomposite was prepared using a facile synthesis method, while XPS and microscopy measurements confirmed the homogenous dispersion of AgNPs on PDA/g-C3N4. AgNPs successfully reduced the recombination rate of photoinduced electron-hole pairs. The calculated bandgap energy was decreased from 2.7 eV for pure g-C3N4 to 2.1 eV for...
An analytic methodology to determine generators redispatch for proactive damping of critical electromechanical oscillations
, Article International Journal of Electrical Power and Energy Systems ; Volume 123 , 2020 ; Parniani, M ; Aminifar, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper presents a model-based method for applying online proactive generators redispatch to improve damping of the critical electromechanical oscillations of power system. The proposed method comprises two stages: 1) monitoring modal characteristics of oscillatory modes in ambient condition, and 2) applying generators redispatch based on sensitivities of the critical mode to the generators active power changes using a new analytic method. An online identification method such as error feedback lattice recursive least square adaptive filter is applied for online estimation of the oscillatory modes. Then, whenever the damping ratio of an identified mode is less than a preset threshold, its...
Sensitivity-based optimal remedial actions to damp oscillatory modes considering security constraints
, Article International Journal of Electrical Power and Energy Systems ; Volume 135 , 2022 ; 01420615 (ISSN) ; Parniani, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper proposes a comprehensive analytic method for applying various optimal remedial actions to improve critical electromechanical modes damping without jeopardizing damping of non-critical modes and violating security constraints of power system. Generators and reactive power sources redisptach, demand side management and the generators voltage reference tuning are remedial actions that are considered here. Dynamic equations of the flux-decay dynamic model of generators, standard dynamic models of excitation system and power system stabilizer and algebraic equations of active and reactive powers balance are formulated in the quadratic eigenvalue problem framework. With simultaneous use...
Development of bioreactors for comparative study of natural attenuation, biostimulation, and bioaugmentation of petroleum-hydrocarbon contaminated soil
, Article Journal of Hazardous Materials ; Volume 342 , 2018 , Pages 270-278 ; 03043894 (ISSN) ; Kariminia, H. R ; Rahmati, M ; Fazlollahi, F ; Polasko, A ; Mahendra, S ; Wilding, W. V ; Fletcher, T. H ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Bioremediation of soil and groundwater sites contaminated by petroleum hydrocarbons is known as a technically viable, cost-effective, and environmentally sustainable technology. The purpose of this study is to investigate laboratory-scale bioremediation of petroleum-hydrocarbon contaminated soil through development of eight bioreactors, two bioreactors for each bioremediation mode. The modes were: (1) natural attenuation (NA); (2) biostimulation (BS) with oxygen and nutrients; (3) bioaugmentation (BA) with hydrocarbon degrading isolates; (4) a combination of biostimulation and bioaugmentation (BS-BA). Total petroleum hydrocarbons (TPH) mass balance over the bioreactors showed about 2% of...
Remediation of trapped DNAPL enhanced by SDS surfactant and silica nanoparticles in heterogeneous porous media: experimental data and empirical models
, Article Environmental Science and Pollution Research ; Volume 27, Issue 3 , 2020 , Pages 2658-2669 ; Khasi, S ; Fatemi, M ; Ghazanfari, M. H ; Sharif University of Technology
Springer
2020
Abstract
The remediation of nonaqueous phase liquids (NAPLs) enhanced by surfactant and nanoparticles (NP) has been investigated in numerous studies. However, the role of NP-assisted surfactants in the dissolution process is still not well discussed. Besides, there is a lack of empirical dissolution models considering the effects of initial residual saturation Strap, NAPL distribution, and surfactant concentration in NAPL-aqueous phase systems. In this work, micromodel experiments are conducted to quantify mass transfer coefficients for different injected aqueous phases including deionized water, SDS surfactant solutions, and NP-assisted solutions with different levels of concentrations and flow...
Dissolution and remobilization of NAPL in surfactant-enhanced aquifer remediation from microscopic scale simulations
, Article Chemosphere ; Volume 289 , 2022 ; 00456535 (ISSN) ; Aminnaji, M ; Rezanezhad, F ; Ghazanfari, M. H ; Babaei, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this paper, the dissolution and mobilization of non-aqueous phase liquid (NAPL) blobs in the Surfactant-Enhanced Aquifer Remediation (SEAR) process were upscaled using dynamic pore network modeling (PNM) of three-dimensional and unstructured networks. We considered corner flow and micro-flow mechanisms including snap-off and piston-like movement for two-phase flow. Moreover, NAPL entrapment and remobilization were evaluated using force analysis to develop the capillary desaturation curve (CDC) and predict the onset of remobilization. The corner diffusion mechanism was also applied in the modeling of interphase mass transfer to represent NAPL dissolution as the dominant mass transfer...
UPFC for enhancing power system reliability
, Article IEEE Transactions on Power Delivery ; Vol. 25, issue. 4 , 2010 , p. 2881-2890 ; ISSN: 8858977 ; Fotuhi-Firuzabad, M ; Shahidehpour, M ; Feuillet, R ; Sharif University of Technology
Abstract
This paper discusses various aspects of unified power flow controller (UPFC) control modes and settings and evaluates their impacts on the power system reliability. UPFC is the most versatile flexible ac transmission system device ever applied to improve the power system operation and delivery. It can control various power system parameters, such as bus voltages and line flows. The impact of UPFC control modes and settings on the power system reliability has not been addressed sufficiently yet. A power injection model is used to represent UPFC and a comprehensive method is proposed to select the optimal UPFC control mode and settings. The proposed method applies the results of a contingency...
UPFC for enhancing power system reliability
, Article IEEE Transactions on Power Delivery ; Volume 25, Issue 4 , 2010 , Pages 2881-2890 ; 08858977 (ISSN) ; Fotuhi Firuzabad, M ; Shahidehpour, M ; Feuillet, R ; Sharif University of Technology
2010
Abstract
This paper discusses various aspects of unified power flow controller (UPFC) control modes and settings and evaluates their impacts on the power system reliability. UPFC is the most versatile flexible ac transmission system device ever applied to improve the power system operation and delivery. It can control various power system parameters, such as bus voltages and line flows. The impact of UPFC control modes and settings on the power system reliability has not been addressed sufficiently yet. A power injection model is used to represent UPFC and a comprehensive method is proposed to select the optimal UPFC control mode and settings. The proposed method applies the results of a contingency...
New hybrid nanocomposite of copper terephthalate MOF-graphene oxide: synthesis, characterization and application as adsorbents for toxic metal ion removal from Sungun acid mine drainage
, Article Environmental Science and Pollution Research ; Volume 24, Issue 28 , 2017 , Pages 22353-22360 ; 09441344 (ISSN) ; Mohaghegh, N ; Sharif University of Technology
Abstract
The application of a hybrid Cu(tpa).GO (Cu(tpa) copper terephthalate metal organic framework, GO graphene oxide) composite as a new adsorbent for the removal of toxic metal ions was reported. New hybrid nanocomposite with excellent dispersibility and stability was successfully fabricated by the simple and effective ultrasonication method. The synthesized composite was characterized by scanning electron microscopy (SEM), UV-Vis and Fourier-transform infrared (FT-IR) techniques. The characterization results concluded that the binding mechanism of the Cu(tpa) and GO was related to both packing and hydrogen bonding. For scrutinizing the sorption activity, the prepared adsorbents were assessed...
Photocatalytic degradation of 3-methyl-4-nitrophenol over Ag/AgCl-decorated/[MOYI]-coated/ZnO nanostructures: Material characterization, photocatalytic performance, and in-vivo toxicity assessment of the photoproducts
, Article Environmental Technology and Innovation ; 2020 ; Heidarpour, H ; Goshadehzehn, M ; Hajiahmadi, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
In this work, a facile ionic liquid-mediated method was utilized to fabricate an efficient photocatalyst for environmental remediation. The eco-friendly aspect of the treatment was explored through an in-vivo toxicity bioassay. ZnO particles, prepared by a combined solid state-pyrolysis method, were coated by 1-methyl-3-(oxiran-2ylmethyl)-1H-imidazolium-3-chloride ([MOYI]Cl) ionic liquid. Then, Ag/AgCl species were grown on the surface to make a heterojunction system leading to efficient charge separation and light absorption extension to the visible domain. The products were characterized by XRD, FTIR, SEM, EDX, DRS, BET, and PL analysis. Photocatalytic performance of the nanostructures was...