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    Super Hydrophobic Ni Coating on Steel by Electrodeposition Method

    , M.Sc. Thesis Sharif University of Technology Nakhaei Niya, Hamzeh (Author) ; Dolati, Abolghasem (Supervisor)
    Abstract
    In this study, the properties of super-hydrophobic Ni coating on carbon steel including wetting behavior and corrosion resistance of Nickel coatings deposited on the steel substrate were investigated. For this purpose, Nickel coatings deposited by electrodeposition method in deferent current density (10,20,30,50, 70 mA /cm2) in bath containing 1.5 mol of ethylene de-ammonium de-chloride, 0.5 mol H3BO3, 1 mol Nicl2.6H2o and then immersed in a bath containing 0.01 mol per liter myristic acid and ethanol for 24 hours and then placed in the room temperature for 14 days. Deferent tests were used for characterization, wettability properties, corrosion behavior and morphology of Ni coatings. The... 

    Estimation of the kinetic parameters of processes at the negative plate of lead-acid batteries by impedance studies

    , Article Journal of Power Sources ; Volume 195, Issue 17 , September , 2010 , Pages 5789-5793 ; 03787753 (ISSN) Rezaei Niya, S. M ; Hejabi, M ; Gobal, F ; Sharif University of Technology
    2010
    Abstract
    Impedance characteristics of the negative electrode of lead-acid battery were derived on the basis of fundamental interfacial processes occurring at the electrode. The solution of the governing equations was presented in terms of a simple equivalent circuit consisting of resistive and capacitive loops in which charge transfer and sulfate layer formation and also mass transfer (Warburg) elements are considered. The kinetic parameters were deduced by fitting the theoretically derived impedance to the experimental data. Impedance at various States of Charge (SoC) was also examined  

    The effect of soil-structure interaction on damage index of buildings

    , Article Engineering Structures ; Volume 30, Issue 6 , 2008 , Pages 1491-1499 ; 01410296 (ISSN) Nakhaei, M ; Ali Ghannad, M ; Sharif University of Technology
    2008
    Abstract
    The effect of Soil-Structure Interaction (SSI) on Park and Ang Damage Index in a Bilinear-SDOF model is investigated under seismic loading. This is done through an extensive parametric study. Two non-dimensional parameters are used as the key parameters which control the severity of SSI: (1) a non-dimensional frequency as the structure-to-soil stiffness ratio index and (2) the aspect ratio of the structure. The soil beneath the structure is considered as a homogeneous elastic half space and is modeled using the concept of Cone Models. The system is then subjected to three different earthquake ground motions as the representative motions recorded on different soil conditions. The analysis is... 

    The effect of soil-structure interaction on hysteretic energy demand of buildings

    , Article Structural Engineering and Mechanics ; Volume 24, Issue 5 , 2006 , Pages 641-645 ; 12254568 (ISSN) Nakhaei, M ; Ghannad, M. A ; Sharif University of Technology
    Techno-Press  2006
    Abstract
    The effect of soil-structure interaction (SSI) on hysteresis energy demand of buildings using an ensemble of alluvium site records was investigated. The structure and the soil were molded separately and then combined to constitute the soil-structure model using the sub-structure method. The key parameters effecting the response of the soil-structure system were found to be a non-dimensional frequency as a representative of structure to soil stiffness ratio; and aspect ratio of the building. It was found that the hysteric energy dissipated in a structure under an earthquake can be highly effected when the stiffness of the soil beneath the structure is altered  

    Multi-rate and multi-quality of service passive optical network based on hybrid WDM/OCDM system [electronic resource]

    , Article IEEE Communications Magazine ; February 2011, Volume 49, Issue 2, PP. S39-S44 Beyranvand, H. (Hamzeh) ; Salehi, J. A ; Sharif University of Technology
    Abstract
    In this article we present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. To provide the requested classes of service, the code weight and code length of MLVW-OOCs are designed based on the characteristics of the requested classes of service. In order to mitigate multiple access interference, we propose to utilize a multilevel signaling technique and interference remover structure based on advanced optical logic gate... 

    Mechanical Design and Fabrication of a Parallel Hybrid Vehicle Powertrain Simulator

    , M.Sc. Thesis Sharif University of Technology Nakhaei, Hamid (Author) ; Saadat Foumani, Mahmoud (Supervisor)
    Abstract
    In this research, the mechanical section of a reduced-scale hybrid vehicle simulator was designed and fabricated. In order to scale down the vehicle dynamics, a method based on dimensional analysis was proposed. An internal combustion engine and an electric motor were selected as power sources and then, scaling was performed, according to the specifications of the combustion engine. Afterwards, the power transmission system was designed first in concept and then in more detail. Finally, the design was manufactured and assembled. The study was made in conjunction with another study responsible for the controlling section of the work, conducted by Safabakhsh The sponsor of these two researches... 

    A Reinforcement Learning Approach for Dynamic Pricing (Case Study: Iran Electrical Power Grid)

    , M.Sc. Thesis Sharif University of Technology Nakhaei, Hamid (Author) ; Shadrokh Sikari, Shahram (Supervisor)
    Abstract
    Population growth and the escalating use of electric devices have led to a surge in electricity demand. However, the construction of adequate infrastructure to meet this additional demand is highly expensive. To address this issue that sometimes causes power outages, dynamic pricing for electricity, a demand management technique, has gained significant importance. By employing this method, prices can be adjusted on an hourly basis, enabling consumers to regulate their consumption in response to these price fluctuations. The prices can be determined based on different objective functions. This research aims to develop a comprehensive framework for determining the optimal hourly electricity... 

    Power quality comparison of active islanding detection methods in a single phase PV grid connected inverter

    , Article IEEE International Symposium on Industrial Electronics, 5 July 2009 through 8 July 2009 ; 2009 , Pages 1852-1857 ; 9781424443499 (ISBN) Hamzeh, M ; Mokhtari, H ; Sharif University of Technology
    2009
    Abstract
    In this paper, the power quality of a single-phase photovoltaic grid connected inverter when uses active islanding detection methods is investigated. Two main groups of these methods are analyzed in this paper. The main focus is on the output power quality of PV sources for these methods. Also the variation of output current THD, while the output power changes, is explored. The variation of output current THD is measured when the parameters of active islanding detection method are changed, and the limitation of these parameters for complying power quality standards in the nominal output power is detected. ©2009 IEEE  

    Probabilistic Comparison of Sustainability of Pavement Maintenance Programs

    , M.Sc. Thesis Sharif University of Technology Zeigham Nakhaei, Mohammad Hossein (Author) ; Tabatabaee, Nader (Supervisor)
    Abstract
    With the increasing importance of the sustainable development perspective, coupled evaluation of the environmental, economic, and functional performance of pavement maintenance programs needs to be considered. This task requires the use of data and models from different sources, which introduce uncertainty in the analysis. The use of probabilistic analysis may allow decision-makers to reach more realistic conclusions. To this end, all phases of the pavement life cycle, including material production, construction, use, and salvage at the end of life, should be considered. The effect of pavement-vehicle interaction (PVI) in the operation phase has received less attention from researchers. In... 

    A decentralized self-adjusting control strategy for reactive power management in an islanded multi-bus MV microgrid

    , Article Canadian Journal of Electrical and Computer Engineering ; Volume 36, Issue 1 , 2013 , Pages 18-25 ; 08408688 (ISSN) Hamzeh, M ; Mokhtari, H ; Karimi, H ; Sharif University of Technology
    2013
    Abstract
    This paper presents a decentralized self-adjusting reactive power controller for the autonomous operation of a multi-bus medium voltage (MV) microgrid. The main objective of the proposed control strategy of each distributed generation (DG) unit is to compensate the reactive power of its local loads and to share the reactive power of the nonlocal loads among itself and other DG units. The proposed control strategy includes an improved droop controller whose parameters are adjusted according to the reactive power of the local loads. A virtual inductive impedance loop is augmented to the voltage controller to enhance the steady state and transient responses of the proposed reactive power... 

    A new control strategy for a multi-bus MV microgrid under unbalanced conditions

    , Article IEEE Transactions on Power Systems ; Volume 27, Issue 4 , 2012 , Pages 2225-2232 ; 08858950 (ISSN) Hamzeh, M ; Karimi, H ; Mokhtari, H ; Sharif University of Technology
    2012
    Abstract
    This paper proposes a new control strategy for the islanded operation of a multi-bus medium voltage (MV) microgrid. The microgrid consists of several dispatchable electronically-coupled distributed generation (DG) units. Each DG unit supplies a local load which can be unbalanced due to the inclusion of single-phase loads. The proposed control strategy of each DG comprises a proportional resonance (PR) controller with an adjustable resonance frequency, a droop control strategy, and a negative-sequence impedance controller (NSIC). The PR and droop controllers are, respectively, used to regulate the load voltage and share the average power components among the DG units. The NSIC is used to... 

    Robust backstepping control of an interlink converter in a hybrid AC/DC microgrid based on feedback linearisation method

    , Article International Journal of Control ; Volume 90, Issue 9 , 2017 , Pages 1990-2004 ; 00207179 (ISSN) Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    2017
    Abstract
    This paper presents a robust dc-link voltage as well as a current control strategy for a bidirectional interlink converter (BIC) in a hybrid ac/dc microgrid. To enhance the dc-bus voltage control, conventional methods strive to measure and feedforward the load or source power in the dc-bus control scheme. However, the conventional feedforward-based approaches require remote measurement with communications. Moreover, conventional methods suffer from stability and performance issues, mainly due to the use of the small-signal-based control design method. To overcome these issues, in this paper, the power from DG units of the dc subgrid imposed on the BIC is considered an unmeasurable... 

    Primary and secondary frequency control in an autonomous microgrid supported by a load-shedding strategy

    , Article PEDSTC 2013 - 4th Annual International Power Electronics, Drive Systems and Technologies Conference ; 2013 , Pages 282-287 ; 9781467344845 (ISBN) Raghami, A ; Ameli, M. T ; Hamzeh, M ; Sharif University of Technology
    2013
    Abstract
    This paper proposes a frequency control strategy for an islanded inverter-based microgrid which based on the priority of supply, has got two distinct types of loads, namely sensitive and deferrable. The proposed strategy consists of primary and secondary levels of generation control supported by a loadshedding scheme. The primary control regulates the output power of the distributed generator (DG) units to be proportional to their ratings while secondary control has got the duty of frequency restoration after each load change. Functionality of these two levels is demonstrated to be independent of each other. Both controls are in distributed forms which have no need of communication... 

    Robust backstepping control of an interlink converter in a hybrid AC/DC microgrid based on feedback linearisation method

    , Article International Journal of Control ; 2016 , Pages 1-15 ; 00207179 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    Abstract
    This paper presents a robust dc-link voltage as well as a current control strategy for a bidirectional interlink converter (BIC) in a hybrid ac/dc microgrid. To enhance the dc-bus voltage control, conventional methods strive to measure and feedforward the load or source power in the dc-bus control scheme. However, the conventional feedforward-based approaches require remote measurement with communications. Moreover, conventional methods suffer from stability and performance issues, mainly due to the use of the small-signal-based control design method. To overcome these issues, in this paper, the power from DG units of the dc subgrid imposed on the BIC is considered an unmeasurable... 

    A backstepping high-order sliding mode voltage control strategy for an islanded microgrid with harmonic/interharmonic loads

    , Article Control Engineering Practice ; Volume 58 , 2017 , Pages 150-160 ; 09670661 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    This paper presents a new nonlinear voltage control strategy based on backstepping control and a high-order sliding mode differentiator for an islanded microgrid. The microgrid consists of multiple distributed generation (DG) units with an arbitrary configuration that can be parametrically uncertain or topologically unknown. The proposed controller robustly regulates the microgrid voltages in the presence of parametric uncertainties, unmodeled dynamics, load imbalances, and nonlinear loads with harmonic/interharmonic currents. In contrast to existing methods, the controller does not need to know the frequency of harmonic and interharmonic current of microgrid loads that lead to the reduction... 

    Distributed robust finite-time secondary voltage and frequency control of islanded microgrids

    , Article IEEE Transactions on Power Systems ; Volume 32, Issue 5 , 2017 , Pages 3648-3659 ; 08858950 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    2017
    Abstract
    This paper presents a distributed, robust, finite-time secondary control for both voltage and frequency restoration of an islanded microgrid with droop-controlled inverter-based distributed generators (DGs). The distributed cooperative secondary control is fully distributed (i.e., uses only the information of neighboring DGs that can communicate with one another through a sparse communication network). In contrast to existing distributed methods that require a detailed model of the system (such as line impedances, loads, other DG units parameters, and even the microgrid configuration, which are practically unknown), the proposed protocols are synthesized by considering the unmodeled... 

    A robust backstepping high-order sliding mode control strategy for grid-connected DG units with harmonic/interharmonic current compensation capability

    , Article IEEE Transactions on Sustainable Energy ; Volume 8, Issue 2 , 2017 , Pages 561-572 ; 19493029 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Abstract
    This paper presents a new nonlinear current control strategy based on backstepping control and high-order sliding mode differentiator in order to employ distributed generation (DG) unit interfacing converters to actively compensate harmonics/interharmonics of local loads. The converter-based DG unit is connected to a weak grid (with uncertain impedance) and local load (that can be parametrically uncertain and topologically unknown) through an LCL filter. The proposed strategy robustly regulates the inverter output currents and delivers pure sinusoidal, three-phase balanced currents to the grid. The new controller demonstrates the robust performance and robust stability of the DG unit system... 

    Fully distributed cooperative secondary frequency and voltage control of islanded microgrids

    , Article IEEE Transactions on Energy Conversion ; Volume 32, Issue 2 , 2017 , Pages 675-685 ; 08858969 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    2017
    Abstract
    This paper proposes a new distributed cooperative secondary control for both frequency and voltage restoration of an islanded microgrid with droop-controlled, inverter-based distributed generations (DGs). Existing distributed methods commonly design secondary control based on the minimum real part of the nonzero Laplacian matrix eigenvalues related to the microgrid communication graph, which, however, is global information. In contrast to the existing distributed methods, in this paper we design a fully distributed adaptive control based on the dynamic model of DG units and on information from neighboring units. Therefore, the proposed control scheme increases the system reliability,... 

    Robust tuning of transient droop gains based on kharitonov's stability theorem in droopcontrolled microgrids

    , Article IET Generation, Transmission and Distribution ; Volume 12, Issue 14 , 2018 , Pages 3495-3501 ; 17518687 (ISSN) Mahdian Dehkordi, N ; Sadati, N ; Hamzeh, M ; Sharif University of Technology
    2018
    Abstract
    This study addresses the robust stability analysis for an islanded microgrid with droop-controlled inverter-based distributed generators (DGs). Owing to large load changes, microgrid structure reconfiguration, and higher-power demands, the low-frequency (LF) dominant modes of a microgrid stir toward unstable zone and make the system more oscillatory or even unstable. In this study, a robust two-degree-of-freedom (2DOF) decentralised droop controller, which is the combination of the conventional droop with a robust transient droop function, is utilised for each inverter-based DG unit. Unlike conventional tuning of 2DOF droop controllers, a new design procedure is proposed to robustly... 

    Rutting and moisture resistance evaluation of polyethylene wax–modified asphalt mixtures

    , Article Petroleum Science and Technology ; Volume 34, Issue 17-18 , 2016 , Pages 1568-1573 ; 10916466 (ISSN) Nakhaei, M ; Darbandi Olia, A. D ; Akbari Nasrekani, A ; Asadi, P ; Sharif University of Technology
    Taylor and Francis Inc  2016
    Abstract
    One of the methods newly introduced in pavement technology to address environmental concerns and reduce total gas emission is warm mix asphalt (WMA) technology. In this study, polyethylene wax is used to produce WMA mixtures. Although this technology has several positive features, moisture and rutting resistance of WMA mixtures are always questionable. To evaluate moisture and rutting resistance of polyethylene-modified mixtures, indirect tensile strength and dynamic creep tests were used, respectively. Results indicated that polyethylene has positive effect at low compaction temperature on moisture resistance, and also has negative effect on rutting resistance