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    A Sectionalizing Method in Power System Restoration Based on Wide Area Measurement Systems

    , M.Sc. Thesis Sharif University of Technology Nezam Sarmadi, Arash (Author) ; Ranjbar, Ali Mohammad (Supervisor)
    Abstract
    Power system restoration is the procedure of restoring generators, transmission lines and loads in a minimum time without damaging power system elements. There are different strategies to restore a power system after a blackout. The one that we will introduce here is the build-upward or parallel restoration strategy. In this method power system will be divided into some independent islands firstly and then the restoration process will begin in each island separately and at the same time. The islands then will be connected together to have a complete restored network. The significant advantage of this strategy is minimizing duration of restoration. On the other hand, the use of Wide Area... 

    Power System Restoration Using Wide Area Measurement System (WAMS)

    , Ph.D. Dissertation Sharif University of Technology Nourizadeh, Saber (Author) ; Ranjbar, Ali Mohammad (Supervisor)
    Abstract
    The introduction of Wide Area Measurement Systems (WAMS) made it possible to monitor the stability online. This thesis presents a method for the optimal restoration planning based on Wide Area Measurement System (WAMS). In fact, the practical use of WAMS at the early stages of restoration provides precise determination of generators loading steps. Moreover, unification of phase angle references at different islands and presentation of tie line energizing priority list are significant benefits of WAMS at the last stages of restoration. The presented method uses observability analysis and Power Transfer Distribution Factor (PTDF) concept. The PTDF concept is applied to decrease the... 

    Distance Relay Blocking in Power Restoration

    , M.Sc. Thesis Sharif University of Technology Sebt-Ahmadi, Mohammad (Author) ; Abbaspour Tehrani Fard, Ali (Supervisor) ; Ranjbar, Ali Mohammad (Supervisor)
    Abstract
    It is possible to unload a transmission line for a while. In line restoration voltage and current of the line will have some dynamic changes. So the apparent impedance of distance relay will have dynamic changes. These changes may cause some bad results including entrance of apparent impedance to the operational zones of distance relay and even relay tripping. Consequently if relay trips, the line restoration process will stop and may not be possible.
    So we want an algorithm to distinguish line restoration from short circuit condition and block the relay. This algorithm must be able to stop blocking if there is any fault in the operational zones of the relay.
    In this thesis an... 

    Frequency Control During Power System Restoration

    , M.Sc. Thesis Sharif University of Technology Yari, Vahid (Author) ; Ranjbar, Ali Mohammad (Supervisor)
    Abstract
    The problem of restoring power systems after a complete or partial blackout is as old as the power industry itself. In recent years, due to economic competition and deregulation, power systems are operated closer and closer to their limits. At the same time, power systems have increased in size and complexity. Both factors increase the risk of major power outages. After a blackout, power needs to be restored as quickly and reliably as possible, and consequently, detailed restoration plants are necessary. This thesis concentrates on the initial stages of restoration where load pickup and frequency control problem is identified. The best sequence of load pickup for power plants during power... 

    Design a Comprehensive Framework for Distribution System Restoration in the Presence of Distributed Generations and Energy Storage Systems

    , Ph.D. Dissertation Sharif University of Technology Riahinia, Shahin (Author) ; Abbaspour Tehrani Fard, Ali (Supervisor) ; Moeini Aghtaie, Moein (Co-Supervisor)
    Abstract
    This thesis presents a stochastic framework to properly involve the uncertainties associated with demand in distribution system restoration (DSR) problem. The restoration process returns the system back to normal operation after any combination of system components have been lost due to an outage. During restoration, the system operator executes a set of actions that progressively mitigate the outage. These actions aim at minimizing the impact of the outage on the final user without compromising the security and operability of the system. In this framework, dynamic programming (DP) is used to solve DSR problem for a distribution system that accommodates various technologies of DG units and... 

    Design of an Efficient High Bandwidth Supply Modulator

    , M.Sc. Thesis Sharif University of Technology Hamidizadeh, Ali (Author) ; Safarian, Amin Ghasem (Supervisor) ; Fotowat Ahmadi, Ali (Supervisor)
    Abstract
    Efficient radio frequency (RF) power amplifiers (PAs) are critical in portable battery-operated wireless communication systems because they can dominate the power consumption. Linear amplifiers are enough linear but suffer from poor efficiency. On the other hand, switching power amplifier are efficient but are nonlinear and just amplify constant envelope signals. Two conventional methods for increasing transmitter efficiency and linearity are envelope elimination and restoration (EER) and envelope tracking (ET). In both methods, supply modulator controls RF power amplifier supply based on the signal envelope. Efficiency and bandwidth are critical factors in supply modulator. Thus hybrid... 

    Investigation of Steel Plate Shear Wall Behavior with Shape Memory Alloy Connection

    , M.Sc. Thesis Sharif University of Technology Haghi, Farzad (Author) ; Mofid, Masoud (Supervisor) ; Mohtasham Dolatshahi, Kiarash (Co-Advisor)
    Abstract
    In recent decades, restoring residual deformations and adding the capability of returning to initial deformed state was investigated by many researchers. Steel Plate Shear Wall (SPSW) is one of structural earthquake resisting system that have high ductility capacity and good energy absorption property. On of major issues in SPSW systems is intense nonlinear deformation in panel’s infill web plate and this panels vertical and horizontal boundary elements. By incorporating Shape Memory Alloy (SMA) connections we can add returning to first deformed condition (self-centering) and sustain high ductility capacity to many structures. In this research the addition of SMA connections to SPSW system... 

    Mahaarloo Salt Lake Restoration Policy Study Using DPSIR Approach

    , M.Sc. Thesis Sharif University of Technology Shoorrahmati, Abdullah (Author) ; Abrishamchi, Ahmad (Supervisor)
    Abstract
    Lakes, marshes, and wetlands shrinkage and drying up due to natural and human driving forces is today one of the most important concerns in the world. Mahaarloo Salt Lake in southern part of Iran is (18 km far from south eastern of Shiraz ) drying-up and is faced with ecologic and environmental degradation. It recharges from western north by upstream basin of Shiraz and 3 rivers named Khoshk, Chenaarrahdaar, Soltaanabad and also from eastern south by Nazarabad river located in Sarvestan basin (Regional water org. of Fars 1382). In recent years, the shrinkage of Mahaarloo has been exacerbated by mismanagement of water resources, inappropriate land use, ignoring allocation of environmental... 

    Upgrading "Qaed Basir"Petrochemical Wastewater Treatment Plant

    , M.Sc. Thesis Sharif University of Technology Maqsudi, Matin (Author) ; Borghei, Mehdi (Supervisor) ; Shayegan Salek, Jalaledin (Supervisor)
    Abstract
    Golpayegan Qaed Basir Petrochemical Company is one of the lucrative and entrepreneurial companies in Iran. Every day in this complex, a large amount of wastewater is being generated and transferred to the evaporative lag after the primary and secondary purification outside the complex and it is not restored. Considering the growing importance of surface and underground water resources, reuse of wastewater is a valuable production. In this research, the optimization of the sewage treatment system of the complex was evaluated by replacing the chemicals in the primary purification unit and also by using chloride-ferric and trickling filter for tertiary purification(treating) of the... 

    Power System Restoration Strategies Realizing the Switching Overvoltages

    , M.Sc. Thesis Sharif University of Technology Helmzadeh, Amin (Author) ; Vakilian, Mahdi (Supervisor)
    Abstract
    Since the power systems usually are being operated close to their nominal capacity due to economical reasons, the probability of wide blackouts in power grids have been increased. However by employing suitable strategies the probability of huge blackouts is still very small but if they occur may put the power system operators in trouble while restoring the system. Thus many studies have been conducted in recent years dealing with power system restoration planning to achieve fast and reliable restoration plans. The scope of this project is overvoltage assessment during system restoration. In this manner we can find the optimal strategy with the least overvoltage problems to prevent the... 

    Re-Creation of Lost Gas Layer on Superhydrophobic Surfaces with Micro/Nanostructures

    , M.Sc. Thesis Sharif University of Technology Jabari Farokhi, Salar (Author) ; Mosavi, Ali (Supervisor)
    Abstract
    Due to their unique characteristics, such as drag reduction, anti-fouling, and enhancing condensation, hydrophobic and superhydrophobic surfaces have attracted a lot of attention in the past decades. Since approximately 4% of the fossil fuel usage and 14-19% of the air pollution (including greenhouse gases, sulfur, and so forth) are attributed to naval activities, and the dominant form of drag on vessels is friction, drag reduction will not only reduce the cost and usage of fossil fuels, but it will also have numerous environmental benefits  

    Seismic Performance Assessment of Historical Structures and Presenting their Seismic Rehabilitation Plan ; a Case Study : Soltanieh Dome

    , M.Sc. Thesis Sharif University of Technology Asgari, Pouya (Author) ; Bakhshi, Ali (Supervisor)
    Abstract
    Preservation of historical monuments is a very important issue for future generations. The importance of this issue is doubled when we know that most of these buildings are traditionally built and do not have a single structure to withstand seismic loads. One of such buildings in our country is Bam Citadel, which was completely destroyed as the oldest brick building in the world during the 2003 Bam earthquake.In this project, we will try to find a model that can determine the structural behavior of the historical dome of Soltanieh for engineers in a case study. This building is a brick dome with a height of 48.5 meters and a diameter of 24.4 meters from the seventh century , which is unique... 

    Effect of microthread design of dental implants on stress and strain patterns: A three-dimensional finite element analysis

    , Article Biomedizinische Technik ; Volume 58, Issue 5 , September , 2013 , Pages 457-467 ; 00135585 (ISSN) Amid, R ; Raoofi, S ; Kadkhodazadeh, M ; Movahhedi, M. R ; Khademi, M ; Sharif University of Technology
    Walter de Gruyter and Co  2013
    Abstract
    The aim of this study was to use finite element analysis (FEA) to assess the influence of microthread design at the implant neck on stress distribution in the surrounding bone. A commercially available implant with 3.5 mm diameter and 10.5 mm length was selected and used as a model. For the purpose of designing the microthread implant model, microthreads were added to the implant neck in a computerized model. A force measuring 100 N was then applied to the entire surface of the abutment in the vertical direction. The results showed that in both models, stress was mainly concentrated at the cortical bone adjacent to the neck of the implant. Maximum stress values in the cortical bone... 

    Robust restoration of distribution systems considering DG units and direct load control programs

    , Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 26, Issue 5 , 2018 , Pages 2676-2687 ; 13000632 (ISSN) Asadi, A ; Fotuhi Firuzabad, M ; Sharif University of Technology
    Turkiye Klinikleri Journal of Medical Sciences  2018
    Abstract
    This paper presents a new method for restoration of distribution networks after a fault occurrence. This problem is solved from the viewpoint of the distribution system operator with the main goal of minimizing the operating cost during the fault clearance period. The effects of distributed generation (DG) units and direct load control (DLC) programs are considered in designing the proposed restoration procedure. Moreover, the uncertainties associated with the predicted loads of different nodes and the availability of DG are modeled here. Robust optimization is used to model the uncertainties of restoration problems and manage their associated risks. Finally, a robust reconfiguration plan is... 

    Incorporation of viscosity scaling group into analysis of MPMS index for laboratory characterization of wettability of reservoir rocks

    , Article Journal of Petroleum Exploration and Production Technology ; Volume 7, Issue 1 , 2017 , Pages 205-216 ; 21900558 (ISSN) Mirzaei Paiaman, A ; Saboorian Jooybari, H ; Masihi, M ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    Wettability is a key parameter affecting petrophysical properties of reservoir rocks. Mirzaei-Paiaman et al. (Energy Fuels 27:7360–7368, 2013) presented an index (referred to as MPMS) for laboratory characterization of wettability of native- or restored-state reservoir rock samples. To use this index two counter-current spontaneous imbibition (COUCSI) experiments are needed, one on the native- or restored-state core sample and another on the strongly water-wet (SWW) reference system. Slope analysis of recovery data in these two systems gives inputs for determination of MPMS index. The two systems must have the same pore structure, initial water saturation, and viscosity ratio. The case 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 Ramezanzadeh, M ; 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... 

    Bioengineering approaches for corneal regenerative medicine

    , Article Tissue Engineering and Regenerative Medicine ; Volume 17, Issue 5 , July , 2020 , Pages 567-593 Mahdavi, S. S ; Abdekhodaie, M. J ; Mashayekhan, S ; Baradaran Rafii, A ; Djalilian, A. R ; Sharif University of Technology
    Korean Tissue Engineering and Regenerative Medicine Society  2020
    Abstract
    Background:: Since the cornea is responsible for transmitting and focusing light into the eye, injury or pathology affecting any layer of the cornea can cause a detrimental effect on visual acuity. Aging is also a reason for corneal degeneration. Depending on the level of the injury, conservative therapies and donor tissue transplantation are the most common treatments for corneal diseases. Not only is there a lack of donor tissue and risk of infection/rejection, but the inherent ability of corneal cells and layers to regenerate has led to research in regenerative approaches and treatments. Methods:: In this review, we first discussed the anatomy of the cornea and the required properties for... 

    Tie-line planning for resilience enhancement in unbalanced distribution networks

    , Article IET Generation, Transmission and Distribution ; 2021 ; 17518687 (ISSN) Taheri, B ; Safdarian, A ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    Over the past decades, there has been a dramatic increase in the frequency of natural disasters, which are the leading causes of large-scale power outages. This paper, therefore, assesses the significance and role of optimal tie-line construction in improving the service restoration performance of unbalanced power distribution systems in the aftermath of high-impact low-probability incidents. In doing so, a restoration process aware stochastic mixed-integer linear programming model is developed to find the optimal locations for new tie-line construction in unbalanced three-phase distribution systems. In particular, the restoration process of distribution systems, including the fault... 

    Fast multidimensional dictionary learning algorithms and their application in 3D inverse synthetic aperture radar image restoration and noise reduction

    , Article IET Radar, Sonar and Navigation ; Volume 16, Issue 9 , 2022 , Pages 1484-1502 ; 17518784 (ISSN) Mehrpooya, A ; Nazari, M ; Abbasi, Z ; Karbasi, S. M ; Nayebi, M. M ; Bastani, M. H ; Sharif University of Technology
    John Wiley and Sons Inc  2022
    Abstract
    By generalising dictionary learning (DL) algorithms to multidimensional (MD) mode and using them in applications where signals are inherently multidimensional, such as in three-dimensional (3D) inverse synthetic aperture radar (ISAR) imaging, it is possible to achieve much higher speed and less computational complexity. In this study, the formulation of the multidimensional dictionary learning (MDDL) problem is expressed and two algorithms are proposed to solve it. The first one is based on the method of optimum directions (MOD) algorithm for 1D dictionary learning (1DDL), which uses alternating minimisation and gradient projection approach. As the MDDL problem is non-convex, the second... 

    Tie-line planning for resilience enhancement in unbalanced distribution networks

    , Article IET Generation, Transmission and Distribution ; Volume 16, Issue 5 , 2022 , Pages 1030-1046 ; 17518687 (ISSN) Taheri, B ; Safdarian, A ; Sharif University of Technology
    John Wiley and Sons Inc  2022
    Abstract
    Over the past decades, there has been a dramatic increase in the frequency of natural disasters, which are the leading causes of large-scale power outages. This paper, therefore, assesses the significance and role of optimal tie-line construction in improving the service restoration performance of unbalanced power distribution systems in the aftermath of high-impact low-probability incidents. In doing so, a restoration process aware stochastic mixed-integer linear programming model is developed to find the optimal locations for new tie-line construction in unbalanced three-phase distribution systems. In particular, the restoration process of distribution systems, including the fault...