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sana--solat
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, M.Sc. Thesis Sharif University of Technology ; Rosta Azad, Reza (Supervisor) ; Yagmaei, Soheila (Supervisor) ; Sana, Solat (Co-Advisor)
Abstract
In this work, biosorption of Zirconium from aqueous solution by A.niger as a biosorbent was investigated. For this goal, both of live and dried biomasses were used. The effect of factors pH, temperature, contact time, initial concentration of metal and biomass dosage were investigated on biosorption. To preparing dried biomass,the live biomass was dried at 60-80 º C for 24 hr and then this dried cell was crushed by mortar and pestle and the drying biomass was ground through a set of sieve with 100 mesh. Also, effect of the pretreatment of biomass by NaOH 0.5 M on biosorption was studied. Optimization of factors was performed by Response Surface Methodology (RSM). The experiments were...
A comparative study on fuzzy damping controller for DFIG wind farms to improve power system oscillations
, Article Journal of Intelligent and Fuzzy Systems ; Volume 37, Issue 4 , 2019 , Pages 4965-4978 ; 10641246 (ISSN) ; Ranjbar, A. M ; Mozafari, B ; Sharif University of Technology
IOS Press
2019
Abstract
Doubly-fed induction generator (DFIG) is the most commonly used technology for wind power generation due to the variable speed performance, decoupled control of active and reactive powers, and high efficiency. However, the DFIG originally cannot participate in damping of power system oscillations since it is not synchronously connected to the power system. This paper proposes an optimal and robust additional damping controller for the DFIG wind turbine to contribute it to damp power system oscillations. It is a fuzzy logic controller that its parameters are optimally tuned using the genetic algorithm (GA). The proposed controller modifies the DFIG active power output by using feedback from...
Coordinated control of doubley fed induction generator virtual inertia and power system oscillation damping using fuzzy logic
, Article International Journal of Engineering, Transactions A: Basics ; Volume 32, Issue 4 , 2019 , Pages 536-547 ; 17281431 (ISSN) ; Ranjbar, A. M ; Mozafari, B ; Sharif University of Technology
Materials and Energy Research Center
2019
Abstract
Doubly-fed induction generator (DFIG) based wind turbines with traditional maximum power point tracking (MPPT) control provide no inertia response under system frequency events. Recently, the DFIG wind turbines have been equipped with virtual inertia controller (VIC) for supporting power system frequency stability. However, the conventional VICs with fixed gain have negative effects on inter-area oscillations of regional networks. To cope with this drawback, this paper proposes a novel adaptive VIC to improve both the inter-area oscillations and frequency stability. In the proposed scheme, the gain of VIC is dynamically adjusted using fuzzy logic. The effectiveness and control performance of...
Biosorption of Uranium from Uranium Conversion Waste using Aspergillus Niger Fungus
, Ph.D. Dissertation Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Yaghmaei, Soheyla (Co-Advisor)
Abstract
Presence of heavy metals in industrial waste has always been a serious environmental problem. One of such metals in uranium that is used in important industries such as nuclear industry. Thus, it must be excluded from industrial waste efficiently. This research aimed to study effect of local strain of aspergillus niger in bioabsoprtion of uranium from industrial waste in which good absorption was reached and absorption of local strain was compared with that of control strain obtained from PTCC. Also, local strain was collected from uranium anomalies of Bandar Abbas Mining Site and was used to identify it with reference strains available at NCBI site using PCR and proliferation of part of...