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    Dataset of biomass characteristics and net output power from downdraft biomass gasifier integrated power production unit

    , Article Data in Brief ; Volume 33 , 2020 Safarian, S ; Ebrahimi Saryazdi, S. M ; Unnthorsson, R ; Richter, C ; Sharif University of Technology
    Elsevier Inc  2020
    This dataset includes 1032 runs from a biomass downdraft gasifier integrated with power production unit that is fed by 86 different types of biomasses from different groups (e.g. wood and woody biomasses, herbaceous and agricultural biomasses, animal biomasses, mixed biomasses and contaminated biomasses) and under various operating conditions. The dataset covers elemental and proximate analysis of various biomasses, operation conditions and the net output power from the biomass gasification-power production (BG-PP) in each case/run. This article has been submitted via another Elsevier journal as a co-submission, titled “Artificial neural network integrated with thermodynamic equilibrium... 

    Output power maximization and optimal symmetric freewheeling excitation for switched reluctance generators

    , Article IEEE Transactions on Industry Applications ; Volume 49, Issue 3 , 2013 , Pages 1031-1042 ; 00939994 (ISSN) Nasirian, V ; Kaboli, S ; Davoudi, A ; Sharif University of Technology
    Space constraint is a limiting factor for the widespread commercial adaptation of switched reluctance generators (SRGs). Maximizing the output power and minimizing the dc bus filter size are thus highly desired. The output power profiles of a typical SRG are determined by applying various excitation angles. Excitation for maximum output power is obtained while limiting the rms value of the phase currents. The dc bus current of an SRG drive, operating in single pulse mode, is highly distorted by low-frequency ripples. Introducing a freewheeling angle in the excitation pattern can lower the current ripple factor. A novel transform is proposed to establish a relationship between the... 

    New strategy for optimization of output power of a DFIG wind turbine

    , Article International Aegean Conference on Electrical Machines and Power Electronics, ACEMP 2011 and Electromotion 2011 Joint Conference ; Sept , 2013 , Pages 69-72 ; 9781467350037 (ISBN) Abedinzadeh, T ; Ehsan, M ; Afsharirad, H ; Nazaraliloo, M ; Sharif University of Technology
    This paper presents a method to maximize the output power of a DFIG wind turbine. In this method, an optimization technique based on mathematical analysis has been used. The modeling of DFIG is performed using MATLAB. To evaluate the maximum output power of a DFIG, detailed expressions for output power and losses are derived as functions of generator slip, the magnitude and phase angle of rotor excitation voltage in various wind velocities. The outcomes of this method demonstrate that maximum output power of a DFIG wind turbine do not happen in the maximum input power (the mechanical power of wind turbine)  

    Construction and Optimization of a Copper Chloride Laser

    , M.Sc. Thesis Sharif University of Technology Farhadi, Leila (Author) ; Sadighi Bonabi, Rasoul (Supervisor)
    Copper vapor Laser is one of the strongest and the most efficient visible laser with high repetition rate. It has been the subject of interest in research, industrial and clinical applications. It’s oscillating lines with 510.5 and 578.2 nm between resonance level and metastable level is acting as pulsed type laser. The problem with this laser is its high operating temperature of 1500 C. This high operating temperature could be reduced by using copper halides, where the temperature decreases from 400 to 500 C. The produced heat will first produce the molecular vapors, then the release and excitation of copper occurs with electrical discharge.
    In the present study the effect of... 

    Wide-band high-efficiency Ku-band power amplifier

    , Article IET Circuits, Devices and Systems ; Vol. 8, issue. 6 , December , 2014 , p. 583-592 ; 1751858X Yousefi, A ; Medi, A ; Sharif University of Technology
    A 37 dBm power amplifier (PA) is designed on a 0.25 μm optical T-gate pseudomorphic high electron mobility transistor (pHEMT) technology. The design of this two-stage PA along with a step-by-step design procedure is presented in this paper. This methodology can be used for design of PA in different technologies and frequencies. The PA delivers 5 W output power over the frequency band of 13-19 GHz. It shows average power-added efficiency of 37% and large signal gain of 15 dB in measurements which is consistent with simulation results. The output power and efficiency of the realised amplifier reach maximums of 37.6 dBm and 45%, respectively. Considering output power, bandwidth, chip area and... 

    Computational study on design parameters of a solar chimney

    , Article International Conference on Sustainable Mobility Applications, Renewables and Technology, 23 November 2015 through 25 November 2015 ; 2015 ; 9781467395298 (ISBN) Esfidani, M. T ; Raveshi, S ; Shahsavari, M ; Sedaghat, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    Today, the production of energy and electricity is one of the major concerns of mankind. Electricity generation by solar energy is considered as one of the alternatives to fossil fuels. Solar chimneys mechanism is based on a natural phenomenon. In this process the solar energy heat up the earth's surface and the surrounding air. Due to the density difference between cold air and warm air, heated air ascends and causes air circulation. In this study, mathematical modelling of solar chimney and governing equations of this system will be discussed. In order to validate the numerical results, upwind velocity in chimney has been compared with a reliable reference results. As well as, the... 

    Investigation of bending and temperature effects in optical fibers

    , Article Microwave and Optical Technology Letters ; Volume 55, Issue 1 , NOV , 2013 , Pages 82-86 ; 08952477 (ISSN) Golnabi, H ; Sharifian, M ; Sharif University of Technology
    Fiber bending and temperature loss mechanisms in plastic optical fibers are reported.A simple arrangement is used to monitor the fiber bending and temperature by output power variation. Powers in the fibers in bend-free situation at room temperature and under rolling deforming force at different water bath temperatures (20-60°C) are measured and compared. Reported arrangements can be used as a temperature sensor  

    Investigation of breakdown voltage in InAIAs/InGaAs/InP HEMTs with different structures

    , Article IEICE Electronics Express ; Volume 7, Issue 19 , 2010 , Pages 1447-1452 ; 13492543 (ISSN) Ohadi, S ; Faez, R ; Hoseini, H. R ; Sharif University of Technology
    InAlAs/InGaAs/InP high electron mobility transistors have higher mobility comparing to structures without indium. But existence of indium causes smaller Eg and as a result smaller breakdown voltage. However, increasing percentage of indium results in higher mobility and as a result higher current and transconductance. Therefore decreasing percentage of indium causes higher breakdown voltage at the sometime lower transconductance. One of the most important parameters that limit maximum output power of transistor is breakdown voltage. In this paper, InAIAs/InGaAs/InP HEMTs with different structures are simulated and a structure with a good transconductance and breakdown voltage is introduced  

    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
    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  

    Study of the dependence of the specific output power of a copper chloride laser on the radial temperature profile of a gas plasma

    , Article Quantum Electronics ; Volume 37, Issue 4 , 2007 , Pages 325-330 ; 10637818 (ISSN) Sadighi Bonabi, R ; Soltanmoradi, F ; Mohammadpour, R ; Tavakoli, M ; Zand, M ; Sharif University of Technology
    The design of a copper chloride laser is described, and the laser is optimised by studying the dependence of its output power on the buffer gas type. The voltage and current of the laser discharge at the optimum buffer gas pressure are measured. The influence of the diaphragm diameter on the specific output power is studied after optimisation of switch parameters. When an diaphragm producing the optimal temperature gradient in the laser gas-discharge tube, the record specific output power of 123 W L-1 is obtained without any admixtures. ©2007 Kvantovaya Elektronika and Turpion Ltd  

    CuCl-Ne laser construction and its optimization on the specific output power

    , Article Lasers and Applications, Warsaw, 28 August 2005 through 2 September 2005 ; Volume 5958 , 2005 , Pages 1-7 ; 0277786X (ISSN) Sadighi Bonabi, R ; Mohammadpour, R ; Tavakoli, M ; Soltanmoradi, F ; Zand, M ; Sharif University of Technology
    In this work, after construction of a copper chloride laser, the effect of using different buffer gases on the output power has been examined. The voltage, current, laser pulses and the far field pattern of laser intensity were measured at the optimum buffer gas pressure. At these favorable conditions, the effect of using diaphragms in different diameters on the specific output power has been studied. By finding the desirable diaphragm size which creates the best temperature gradient in the laser tube the specific output record power of 123 (Watt/Lit) was obtained  

    Design of 6-18-GHz high-power amplifier in GaAs pHEMT technology

    , Article IEEE Transactions on Microwave Theory and Techniques ; Volume 65, Issue 7 , 2017 , Pages 2353-2360 ; 00189480 (ISSN) Meghdadi, M ; Medi, A ; Sharif University of Technology
    This paper presents a design procedure for a wideband 6-18-GHz monolithic microwave integrated circuit highpower amplifier (HPA) in 0.25-μm AlGaAs-InGaAs pHEMT technology. The design is mainly focused on the realization of the passive circuits to provide the required low-loss and wideband impedance transformation networks. The two-stage GaAs HPA achieves an average output power of 39.6 dBm and a peak output power of 40.5 dBm at 11 GHz, in pulsed mode operation, with a small-signal gain of S21 > 10 dB over the entire bandwidth. The average power added efficiency (PAE) is 22%, with a peak PAE of 29% at 11 GHz. The HPA chip occupies an area of 5×3.6 mm2. The achieved output power and the... 

    Down-conversion self-oscillating mixer by using CMOS technology

    , Article Proceedings - 2012 IEEE 8th International Colloquium on Signal Processing and Its Applications, CSPA 2012 ; 2012 , Pages 33-36 ; 9781467309615 (ISBN) Kouchaki, M ; Zahedi, A ; Sabaghi, M ; Ameri, S. R. H ; Niyakan, M ; Sharif University of Technology
    In this paper a self-oscillating mixer is presented fundamental signal generated by the oscillator subcircuit in the mixing process. The oscillator core consumes 3mA of current from a 1.8 V DC supply and results in an output power of -0.867 dBm per oscillator, and a measured phase noise of -91, -102 and -108 dBc/Hz at 100 KHz, 600 KHz and 1 MHz from the carrier, respectively. In the mixing process the proposed mixer achieved IIP3 of 0 dBm with conversation gain of 1.93 dB. The circuit was designed and simulated in 0.18-μm CMOS technology by ADS2010  

    Performance optimization of solar chimney power plant using electric/corona wind

    , Article Journal of Electrostatics ; Volume 78 , 2015 , Pages 22-30 ; 03043886 (ISSN) Nasirivatan, S ; Kasaeian, A ; Ghalamchi, M ; Ghalamchi, M ; Sharif University of Technology
    Elsevier  2015
    The effect of the corona wind on the natural convection at absorber of a solar chimney power plant pilot was investigated experimentally. The aim of the study is to improve the efficiency of SCPP through enhanced the heat transfer coefficient of absorber with corona wind. The results show that corona wind enhanced the absorber convective heat transfer coefficient leading to increment in air the velocity and the output power of the SCPP. The amount of heat transfer of pilot increased more than 14.5% when applying voltage of 15 KV and the speed in chimney experienced about 72% amelioration  

    Fuzzy modeling techniques and artificial neural networks to estimate annual energy output of a wind turbine

    , Article Renewable Energy ; Volume 35, Issue 9 , September , 2010 , Pages 2008-2014 ; 09601481 (ISSN) Jafarian, M ; Ranjbar, A. M ; Sharif University of Technology
    The purpose of this article is to develop a new method to estimate annual energy output for a given wind turbine in any region which should be easy to use and has satisfactory accuracy. To do this, hourly wind speeds of 25 different stations in Netherlands, output power curve of S47 wind turbine and fuzzy modeling techniques and artificial neural networks were used and a model is developed to estimate annual energy output for S47 wind turbine in different regions. Since this model has three inputs (average wind speed, standard deviation of wind speed, and air density of that region), this model is easy to use. The accuracy of this method is compared with the accuracy of conventional methods... 

    Energy and exergy analysis of a gas turbine power plant with inlet evaporating cooling systems

    , Article 23rd International Conference on Efficiency, Cost, Optimization, Simulation, and Environmental Impact of Energy Systems, 14 June 2010 through 17 June 2010 ; Volume 4 , 2010 , Pages 203-210 ; 9781456303181 (ISBN) Ameri, M ; Karimi, M ; Ahmadi, P ; Ecole Polytechnique Federale de Lausanne; Schweizerische Eidgenossenschaft ; Sharif University of Technology
    Aabo Akademi University 
    The gas turbine (GT) is known to feature low capital cost to power ratio, high flexibility, high reliability without complexity, short delivery time, early commissioning and commercial operation and fast starting-accelerating. Hence, researchers all over the world are working to increase the output power and efficiency of gas turbine cycle. One of the important techniques to increase the output power of such cycles is the compressor inlet air cooling method. The objective of this paper is to analysis the gas turbine cycle from both energy and exergy point of view. Thus, two important methods for increasing the output power, i.e. fog and media inlet air cooling systems are discussed.... 

    Smart power management of DC microgrids in future milligrids

    , Article 2016 18th European Conference on Power Electronics and Applications, EPE 2016 ECCE Europe, 5 September 2016 through 9 September 2016 ; 2016 ; 9789075815245 (ISBN) Peyghami Akhuleh, S ; Mokhtari, H ; Davari, P ; Loh, P. C ; Blaabjerg, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    In this paper a novel droop approach for power management in low voltage dc MicroGrids (MGs) based on a master-slave concept is presented. A virtual frequency is injected by a master unit, which is proportional to its output power. Other slave units determine their output power according to the corresponding frequency based droop characteristics. Unlike the dc voltage-droop methods, the proposed virtual frequency-droop approach can be smartly applied for proportional power management among the energy units and loads as well as adding zero net energy capability to the MG. Both power flow and energy flow can be performed without utilizing an extra communication system. Simulation results... 

    Optimum design of coils in a dynamic wireless electric vehicle charger with misalignment compensation capability

    , Article 8th Power Electronics, Drive Systems and Technologies Conference, PEDSTC 2017, 14 February 2017 through 16 February 2017 ; 2017 , Pages 419-424 ; 9781509057665 (ISBN) Poorfakhraei, A ; Movaghar, G ; Tahami, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2017
    Electric vehicles have been proposed as a proper replacement for fossil fuel-powered vehicles; however, due to the limited power density of electric vehicles batteries, these cars have been facing formidable challenges, such as limited traversed distance. In recent years, dynamic wireless chargers are introduced as an adequate way of addressing this problem in the hope that dealing with this issue can lead to an increase in the popularity of electric vehicles. In this paper, a design procedure for transmitter coil of a dynamic wireless electric vehicles charger is proposed. The procedure includes selecting the best possible shape and calculating optimum size of coils for proper operation of... 

    Characteristic curves of solar tower

    , Article American Solar Energy Society - Solar 2007: 36th ASES Annual Conf., 32nd National Passive Solar Conf., 2nd Renewable Energy Policy and Marketing Conference: Sustainable Energy Puts America to Work, 8 July 2007 through 12 July 2007, Cleveland, OH ; Volume 1 , 2007 , Pages 149-156 ; 9781604233087 (ISBN) Khoshmanesh, S ; Sharif University of Technology
    Large scale solar tower are capable of generating electricity at the costs comparable to those of conventional power plant. Three cost effective parameters in solar tower are diameter of collector, diameter of turbine and height of tower. The characteristic curves of the solar tower mean the relation between cost effective parameters at the specified output power. The solar tower can be equipped with water-filled bags underneath of the collector system for thermal energy storage. This research prepares all of the required relation to setup the mathematical program to find the characteristics curves of solar tower without using the water-filled bags and with using the water-filled bags. The... 

    A 10-W X-Band class-f high-power amplifier in a 0.25-μm GaAs pHEMT technology

    , Article IEEE Transactions on Microwave Theory and Techniques ; Volume 69, Issue 1 , 2021 , Pages 157-169 ; 00189480 (ISSN) Alizadeh, A ; Yaghoobi, M ; Meghdadi, M ; Medi, A ; Kiaei, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    In this article, a design methodology is presented to realize integrated class-F high-power amplifiers (HPAs). A harmonic-control network (HCN) is proposed to present short- and open-circuit impedances to each transistor employed in the output stage of the HPA at {2}f {0} and {3}f {0} frequencies. The HCN absorbs the parasitic capacitance of the transistor and lends itself to be absorbed in the matching and power combiner networks, reducing the die area of the HPA. A proof-of-concept 9.7-10.3-GHz class-F HPA was designed and implemented in a 0.25- μ ext{m} GaAs pHEMT technology with V {DD} of 6 V. The designed HPA consists of two amplifying stages, and its output stage includes 16...