The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Rahul Pandit - One of the best experts on this subject based on the ideXlab platform.
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ventricular fibrillation in a simple excitable medium model of cardiac tissue
International Journal of Modern Physics B, 2003Co-Authors: T. K. Shajahan, Sitabhra Sinha, Rahul PanditAbstract:Ventricular fibrillation (VF), the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in spatiotemporal electrical activation of heart make it incapable of any concerted Pumping Action. We give a brief overview of the simple Panfilov model for ventricular fibrillation, with emphasis on studies that have elucidated the nature of spiral turbulence which is the analog of VF here. The control of such turbulence is briefly touched upon. Preliminary results are presented for the effects of conduction inhomogeneity on spiral breakup, and the transition from functional to anatomical reentry as a function of the size and position of the inhomogeneity.
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defibrillation via the elimination of spiral turbulence in a model for ventricular fibrillation
Physical Review Letters, 2001Co-Authors: Rahul Pandit, Sitabhra Sinha, Ashwin S PandeAbstract:Ventricular fibrillation, the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in the spatiotemporal electrical activation of the heart make it incapable of any concerted Pumping Action. Methods of controlling ventricular fibrillation include electrical defibrillation as well as injected medication. Electrical defibrillation, though widely used, involves subjecting the whole heart to massive, and often counterproductive, electrical shocks. We propose a defibrillation method that uses a very low-amplitude shock (of order mV) applied for a brief duration (of order 100 ms) and over a coarse mesh of lines on our model ventricle.
Sitabhra Sinha - One of the best experts on this subject based on the ideXlab platform.
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ventricular fibrillation in a simple excitable medium model of cardiac tissue
International Journal of Modern Physics B, 2003Co-Authors: T. K. Shajahan, Sitabhra Sinha, Rahul PanditAbstract:Ventricular fibrillation (VF), the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in spatiotemporal electrical activation of heart make it incapable of any concerted Pumping Action. We give a brief overview of the simple Panfilov model for ventricular fibrillation, with emphasis on studies that have elucidated the nature of spiral turbulence which is the analog of VF here. The control of such turbulence is briefly touched upon. Preliminary results are presented for the effects of conduction inhomogeneity on spiral breakup, and the transition from functional to anatomical reentry as a function of the size and position of the inhomogeneity.
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defibrillation via the elimination of spiral turbulence in a model for ventricular fibrillation
Physical Review Letters, 2001Co-Authors: Rahul Pandit, Sitabhra Sinha, Ashwin S PandeAbstract:Ventricular fibrillation, the major reason behind sudden cardiac death, is turbulent cardiac electrical activity in which rapid, irregular disturbances in the spatiotemporal electrical activation of the heart make it incapable of any concerted Pumping Action. Methods of controlling ventricular fibrillation include electrical defibrillation as well as injected medication. Electrical defibrillation, though widely used, involves subjecting the whole heart to massive, and often counterproductive, electrical shocks. We propose a defibrillation method that uses a very low-amplitude shock (of order mV) applied for a brief duration (of order 100 ms) and over a coarse mesh of lines on our model ventricle.
Paul Galambos - One of the best experts on this subject based on the ideXlab platform.
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Flow field analysis in a spiral viscous micropump
Microfluidics and Nanofluidics, 2007Co-Authors: Yousef Haik, Mohammad Kilani, Jason Hendrix, Omar Al Rifai, Paul GalambosAbstract:The paper presents a stream function solution and a computational analysis for the flow field of a viscous spiral pump, which employs a rotating spiral channel to achieve Pumping Action. This pump is fabricated using surface micromachining technology. The stream function solution employs a simplified 2D model for the flow field in its spiral channel that neglects the curvature of the spiral, and replaces it with an equivalent straight channel. The effect of spiral wall height on flow rate is analyzed and discussed. 3D computational analyses are obtained and are compared with analytical predictions.
Ryozo Itoh - One of the best experts on this subject based on the ideXlab platform.
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Single-phase two-stage boost rectifiers with sinusoidal input current
IET Power Electronics, 2010Co-Authors: Yasuhiko Neba, Kouichi Ishizaka, Ryozo ItohAbstract:Single-phase two-state boost rectifiers with sinusoidal input current are presented and a novel topology with two active power devices is proposed. These contain a capacitor for Pumping Action in DC circuit. This gives two-stage boost operation to obtain higher DC output voltage. The rectifier can be operated in the switch mode for Pumping Action and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The results of the proposed rectifier are compared with those of the rectifier with a single active power device. The prototype tested is implemented to investigate the steady-state operation in the output voltage regulation. The experimental and the simulated results prove that the proposed rectifier has the expected performance.
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Single-Phase Boost Rectifier Adding a Capacitor for Pumping Action in DC Circuit
IEEJ Transactions on Industry Applications, 2007Co-Authors: Hayato Oishi, Yasuhiko Neba, Kouichi Ishizaka, Ryozo ItohAbstract:To obtain higher DC output voltage, a single-phase boost rectifier adding a capacitor for Pumping Action in DC circuit is studied. This gives two-stage boost operation by means of inductive and capacitive energy storage/transfer mechanisms under the high-frequency switching. The experimental prototype, employing an insulated-gate bipolar transistor as an active power switching device and a PI controller for output voltage regulation, is implemented to investigate the operation. The experimental results confirm that the input current can almost be waveshaped sinusoidally with a near-unity power factor by the current-mode control.
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Switch-mode voltage-doubler rectifier with symmetrical arrangement of capacitors for Pumping Action
IEE Proceedings - Electric Power Applications, 2005Co-Authors: Yasuhiko Neba, Kouichi Ishizaka, Ryozo ItohAbstract:A novel switch-mode voltage-doubler rectifier for single-phase supply is presented. It consists of diode bridge circuit and pump circuit with symmetrical arrangement of capacitors. The capacitors with energy storage/transfer capability are charged and discharged by employing the active power semiconductor devices. The rectifier can be operated in the switch mode for Pumping Action to pump twice the peak supply voltage into the output capacitor and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The prototype tested, using two dual-IGBT power modules, has been implemented to investigate the operation with a PI controller for output voltage regulation. Experimental and simulated results are provided to verify the expected performance in both steady-state and transient conditions.
Yousef Haik - One of the best experts on this subject based on the ideXlab platform.
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Flow field analysis in a spiral viscous micropump
Microfluidics and Nanofluidics, 2007Co-Authors: Yousef Haik, Mohammad Kilani, Jason Hendrix, Omar Al Rifai, Paul GalambosAbstract:The paper presents a stream function solution and a computational analysis for the flow field of a viscous spiral pump, which employs a rotating spiral channel to achieve Pumping Action. This pump is fabricated using surface micromachining technology. The stream function solution employs a simplified 2D model for the flow field in its spiral channel that neglects the curvature of the spiral, and replaces it with an equivalent straight channel. The effect of spiral wall height on flow rate is analyzed and discussed. 3D computational analyses are obtained and are compared with analytical predictions.
