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Decorated CNT based on porous silicon for hydrogen gas sensing at room temperature
, Article RSC Advances ; Volume 6, Issue 50 , 2016 , Pages 44410-44414 ; 20462069 (ISSN) ; Razi Astaraei, F ; Fardindoost, S ; Hosseini, Z. S ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A new triple-component sensor for detection of H2 was developed based on porous silicon and CNTs. An increase in deposition of CVD catalysis was shown to promote a high and fast response. Also, it was shown that the composite system exhibited good selectivity
Dynamic and vibration analysis of a 3-serial-link micro/nano-manipulator with piezoelectric actuation
, Article Microsystem Technologies ; Volume 27 , July , 2020 , Pages 703–721 ; Ahmadian, M. T ; Sharif University of Technology
Springer
2020
Abstract
In this work, the dynamic and vibrational behavior of a micro/nano-manipulator has been studied. The manipulator comprises three links attached serially. While the connection of the links is rigid, which makes the whole body a monolithic structure, the movement of the manipulator is derived from the links deflection. Piezoelectric layers were employed as an actuator to impose deflection on the links, thereby moving the manipulator. After defining the dynamic behavior of each link, manipulator equations of motion were developed. To evaluate the validity of the mathematical model, two FEM models were constructed. The observed results showed a good agreement between the models, and they...
Dynamic and vibration analysis of a 3-serial-link micro/nano-manipulator with piezoelectric actuation
, Article Microsystem Technologies ; Volume 27, Issue 3 , 2021 , Pages 703-721 ; 09467076 (ISSN) ; Ahmadian, M. T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this work, the dynamic and vibrational behavior of a micro/nano-manipulator has been studied. The manipulator comprises three links attached serially. While the connection of the links is rigid, which makes the whole body a monolithic structure, the movement of the manipulator is derived from the links deflection. Piezoelectric layers were employed as an actuator to impose deflection on the links, thereby moving the manipulator. After defining the dynamic behavior of each link, manipulator equations of motion were developed. To evaluate the validity of the mathematical model, two FEM models were constructed. The observed results showed a good agreement between the models, and they...
A compact versatile microbial fuel cell from paper
, Article ASME 2013 11th Int. Conf. on Fuel Cell Science, Eng. and Technology Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 7th Int. Conf. on Energy Sustainability, FUELCELL 2013 ; 2013 ; 9780791855522 (ISBN) ; Hashemi, N ; Hashemi, N ; Sharif University of Technology
2013
Abstract
Microbial fuel cells (MFCs) have been a potential green energy source for a long time but one of the problems is that either the technology must be used on a large scale or special equipment have been necessary to keep the fuel cells running such as syringe pumps. Paper-based microbial fuel cells do not need to have a syringe pump to run and can run entirely by themselves when placed in contact with the fluids that are necessary for it to run. Paper-based microbial fuel cells are also more compact than traditional MFCs since the device doesn't need any external equipment to run. The goal of this paper is to develop a microbial fuel cell that does not require a syringe pump to function. This...
Emergence of bursting in two coupled neurons of different types of excitability
, Article Chaos, Solitons and Fractals ; Volume 132 , 2020 ; Yasaman, S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this manuscript, a spiking neuron of type I excitability and a silent neuron of type II excitability are coupled through a gap junction with unequal coupling strengths, and none of the coupled neurons can burst intrinsically. By applying the theory of dynamical systems (e.g. bifurcation theory), we investigate how the coupling strength affects the dynamics of the neurons, when one of the coupling strengths is fixed and the other varies. We report four different regimes of oscillations as the coupling strength increases. (1) Spike–Spike Phase–Locking, where both neurons are in tonic spiking mode but with different frequencies; (2) Spike–Burst mode, where the type II neuron bursts while the...
Skip cycle controlled resonant converter with high efficiency over wide load range
, Article 4th IET International Conference on Power Electronics, Machines and Drives, PEMD 2008, York, 2 April 2008 through 4 April 2008 ; Issue 538 CP , 2008 , Pages 742-746 ; 9780863419003 (ISBN) ; Alavi, M. H ; Oraee, H ; Sharif University of Technology
2008
Abstract
Due to the fast response of skip cycle modulation technique, it has been used to control of some DC/DC converters. In this paper, it is used to control of a series resonant converter. A pulse generator circuit is presented for zero current switching. Simulation and experimental results are presented to show the features of this control method. Results show that the converter has a fast response and high efficiency. Design notes about magnetic parts of converter are also presented to achieve the highest efficiency
A fast vacuum ARC detection method based on the neural network data fusion algorithm for the high-voltage DC power supply of vacuum tubes.رر
, Article IEEE Transactions on Plasma Science ; Volume 49, Issue 1 , 2021 , Pages 476-485 ; 00933813 (ISSN) ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Vacuum arc is one of the most important failure factors of the vacuum tubes. The amount of delivered energy from the high-voltage dc power supply to the vacuum tube is an important issue during the vacuum arc in the tube. Vacuum arc acts as a short-circuit fault (SCF) at the power supply output. The majority of converters use a single current sensor to measure only the converter output current for detecting the SCF. However, the sensor may provide unreliable data because of the noise effect. Application of a low-pass filter reduces the noise effect. Regarding the delay of the low-pass filter, the interval of arc detection increases and more energy is delivered to the tube. In this article, a...
Copper oxide nanoflakes as highly sensitive and fast response self-sterilizing biosensors
, Article Journal of Materials Chemistry ; Volume 21, Issue 34 , Jul , 2011 , Pages 12935-12940 ; 09599428 (ISSN) ; Ghaderi, E ; Sharif University of Technology
2011
Abstract
Vertical copper oxide nanoflakes were synthesized on a Cu foil through oxidation in alkaline conditions. X-ray photoelectron spectroscopy showed that after exposing the nanoflakes to an Escherichia coli bacterial suspension, the outermost surface of the nanoflakes was chemically reduced through the glycolysis process of the bacteria. Current-voltage (I-V) characteristics of the nanoflakes (measured perpendicular to surface of the Cu foil by using conductive atomic force microscopy) indicated that electrical resistivity of the nanoflakes increased about one order of magnitude after exposure to the bacterial suspension. The nanoflakes reduced by the bacterial suspension could also be...
Online optimal neuro-fuzzy flux controller for DTC based induction motor drives
, Article 24th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2009, Washington, DC, 15 February 2009 through 19 February 2009 ; 2009 , Pages 210-215 ; 9781424428120 (ISBN) ; Kaboli, S ; Adeli, H ; Hajipour, E ; Ferdowsi, M ; Power Sources Manufacturers Association; IEEE Power Electronics Society; IEEE Industry Applications Society; APEC Steering Committee Members with Sponsoring Organizations ; Sharif University of Technology
2009
Abstract
In this paper a fast flux search controller based on the Neuro-fuzzy systems is proposed to achieve the best efficiency of a direct torque controlled induction motor at light load. In this method the reference flux value is determined through a minimization algorithm with stator current as objective function. This paper discusses and demonstrates the application of Neurofuzzy filtering to stator current estimation. Simulation and experimental results are presented to show the fast response of proposed controller. © 2009 IEEE
A Fast vacuum arc detection method based on the neural network data fusion algorithm for the high-voltage dc power supply of vacuum tubes
, Article IEEE Transactions on Plasma Science ; 2020 ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Vacuum arc is one of the most important failure factors of the vacuum tubes. The amount of delivered energy from the high-voltage dc power supply to the vacuum tube is an important issue during the vacuum arc in the tube. Vacuum arc acts as a short-circuit fault (SCF) at the power supply output. The majority of converters use a single current sensor to measure only the converter output current for detecting the SCF. However, the sensor may provide unreliable data because of the noise effect. Application of a low-pass filter reduces the noise effect. Regarding the delay of the low-pass filter, the interval of arc detection increases and more energy is delivered to the tube. In this article, a...
Direct-DMC for AQM computational complexity reduction in TCP/IP networks
, Article International Conference on Control, Automation and Systems, ICCAS 2007, Seoul, 17 October 2007 through 20 October 2007 ; December , 2007 , Pages 1270-1273 ; 8995003871 (ISBN); 9788995003879 (ISBN) ; Haeri, M ; Sharif University of Technology
2007
Abstract
Active queue management (AQM) mechanisms are designed to provide better support for end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP/IP networks. This paper introduces Direct Dynamic Matrix Control (D-DMC) as a new AQM method in dynamic TCP networks. Ability of the controller in handling system delay along with its simplicity and low computational loads makes D-DMC a privileged AQM method in high speed networks. The controller is designed based on a small signal linearized fluid-flow model of TCP/AQM networks. The computational complexity analysis as well as the MATLAB simulation results shows the out-performance of the developed controller for both...
The decoration of TiO2/reduced graphene oxide by Pd and Pt nanoparticles for hydrogen gas sensing
, Article International Journal of Hydrogen Energy ; Volume 37, Issue 20 , 2012 , Pages 15423-15432 ; 03603199 (ISSN) ; Ghasemi, S ; Irajizad, A ; Akhavan, O ; Gholami, M. R ; Sharif University of Technology
Elsevier
2012
Abstract
Reduced graphene oxide (RGO) was used to improve the hydrogen sensing properties of Pd and Pt-decorated TiO2 nanoparticles by facile production routes. The TiO2 nanoparticles were synthesized by sol-gel method and coupled on GO sheets via a photoreduction process. The Pd or Pt nanoparticles were decorated on the TiO2/RGO hybrid structures by chemical reduction. X-ray photoelectron spectroscopy demonstrated that GO reduction is done by the TiO2 nanoparticles and Ti-C bonds are formed between the TiO2 and the RGO sheets as well. Gas sensing was studied with different concentrations of hydrogen ranging from 100 to 10,000 ppm at various temperatures. High sensitivity (92%) and fast response time...
Small-signal modeling and fast response control strategy for DCVM Cúk converters in PFC applications.انجام شد
, Article Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC ; 2011 , Pages 1795-1802 ; 9781424480845 (ISBN) ; Karimi, Y ; Zolghadri, M. R ; Ahmadian, M ; Moayedi, A ; Davoudi, A ; Sharif University of Technology
Abstract
Cúk Converter operating in discontinuous capacitor voltage mode is an inherent PFC converter in which, unity power factor can be achieved using constant duty cycle and switching frequency. In this paper, a reduced-order switch network modeling technique is applied to Cúk converter operating in DCVM in order to derive small-signal model of the converter assuming a dc voltage source as the input source of the converter. This model is extended to derive the small-signal behavior of the converter while operating as a PFC converter. The validity of the proposed model is confirmed by both simulation and experimental results. Afterwards, a new control strategy is proposed in which switching...
Intelligent regime recognition in upward vertical gas-liquid two phase flow using neural network techniques
, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM, 1 August 2010 through 5 August 2010, Montreal, QC ; Volume 2 , 2010 , Pages 293-302 ; 08888116 (ISSN) ; 9780791849491 (ISBN) ; Hanafizadeh, P ; Saidi, M. H ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
2010
Abstract
In order to safe design and optimize performance of some industrial systems, it's often needed to categorize two-phase flow into different regimes. In each flow regime, flow conditions have similar geometric and hydrodynamic characteristics. Traditionally, flow regime identification was carried out by flow visualization or instrumental indicators. In this research3 kind of neural networks have been used to predict system characteristic and flow regime, and results of them were compared: radial basis function neural networks, self organized and Multilayer perceptrons (supervised) neural networks. The data bank contains experimental pressure signalfor a wide range of operational conditions in...
Predictive functional control for active queue management in congested TCP/IP networks
, Article ISA Transactions ; Volume 48, Issue 1 , 2009 , Pages 107-121 ; 00190578 (ISSN) ; Haeri, M ; Sharif University of Technology
2009
Abstract
Predictive functional control (PFC) as a new active queue management (AQM) method in dynamic TCP networks supporting explicit congestion notification (ECN) is proposed. The ability of the controller in handling system delay along with its simplicity and low computational load makes PFC a privileged AQM method in the high speed networks. Besides, considering the disturbance term (which represents model/process mismatches, external disturbances, and existing noise) in the control formulation adds some level of robustness into the PFC-AQM controller. This is an important and desired property in the control of dynamically-varying computer networks. In this paper, the controller is designed based...
Active queue management of TCP/IP networks using rule-based predictive control
, Article 2007 IEEE International Symposium on Industrial Electronics, ISIE 2007, Caixanova - Vigo, 4 June 2007 through 7 June 2007 ; 2007 , Pages 77-82 ; 1424407559 (ISBN); 9781424407552 (ISBN) ; Bigdeli, N ; Haeri, M ; Sharif University of Technology
2007
Abstract
Model predictive controllers, due to their capability to control the time variant and delayed systems, are considered for congestion control in computer networks. To extend the application of these controllers as an active queue management (AQM) system in dynamic TCP/IP networks, a new rule-based predictive controller is proposed. This controller uses the small signal linearized fluid-flow model of the TCP/IP networks and simulates the future behavior of control system by applying few candidate control sequences. Using the extremes of the resulted predicted output sequences, optimal control signal is determined based on some appropriate rules. This approach benefits from the mentioned...