Home About us Contact
|
Home About us Contact | ||
|
|
||
Circuit Components (circuit + component)
Selected AbstractsComparison of Pumps and Oxygenators With Pulsatile and Nonpulsatile Modes in an Infant Cardiopulmonary Bypass ModelARTIFICIAL ORGANS, Issue 11 2009Nikkole M. Haines Abstract As the evidence mounts in favor of pulsatile perfusion during CPB, it is necessary to investigate the effect of circuit components on the quality of pulsatility delivered throughout the circuit. We compared two bloodpumps, the Jostra HL-20 heart-lung machine and the MEDOS DELTASTREAM DP1 Bloodpump, and two oxygenators, the Capiox Baby RX05 and the MEDOS HILITE 800LT, in terms of mean arterial pressure, energy equivalent pressure, surplus hemodynamic energy, total hemodynamic energy, and pressure drop over the oxygenators using a blood analog. The pumps and oxygenators were combined in unique circuits and tested in nonpulsatile and pulsatile modes, at two flow rates (500 and 800 mL/min), and three rotational speed differentials when using the MEDOS DELTASTREAM DP1 Bloodpump for 144 trials in total. The Jostra Roller pump produced some pulsatility in nonpulsatile mode and better pulsatility in pulsatile mode than the MEDOS DP1 Bloodpump at a rotational speed differential of 2500 rpm, but not at 3500 or 4500 rpm. The MEDOS DP1 Bloodpump produced almost no pulsatility in nonpulsatile mode. Pressure drops over the Capiox Baby RX05 were markedly higher, at 92.5 ± 0.4 mm Hg with the MEDOS DP1 Bloodpump at 800 mL/min and 4500 rpm in pulsatile mode, than those of the MEDOS HILITE 800LT oxygenator, which was 67.0 ± 0.1 mm Hg at the same settings. These results suggest that careful selection of each circuit component, based on the individual clinical case and component specifics, are necessary to achieve the best quality of pulsatility. [source] Third-order passive load identification under non-sinusoidal conditionsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2002P. Mattavelli This paper presents an extension of the well known load identification method, valid under non-sinusoidal conditions, which makes use of a 2nd -order passive circuit and an auxiliary voltage or current generator. The proposed solution is similar, but uses a 3rd -order passive circuit. This allows to identify the passive circuit components with positive or negative parameters, according to the aim of the identification (load modeling or compensation). Moreover, the proposed approach keeps the orthogonality between current/voltage components and removes the indetermination which occurs, with the 2nd -order approach, in the case of sinusoidal operation. As an application example, the proposed approach is applied to the design of a hybrid compensation system including active and passive filtering. [source] Design and implementation of an interleaved soft-switching converter with output voltage doublerINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2010B.-R. Lin Abstract An interleaved pulse-width modulation (PWM) converter with less power switches is presented in this paper. The buck type of active clamp circuit is used to recycle the energy stored in the leakage inductor of a transformer. The zero voltage switching (ZVS) turn-on of power switches is realized by the resonance during the transition interval of power switches. At the secondary side of transformers, two full-wave rectifiers with dual-output configuration are connected in parallel to reduce the current stresses of the secondary windings of transformers. In the proposed converter, power switches can accomplish two functions of the interleaved PWM modulation and active clamp feature at the same time. Therefore, the circuit components in the proposed converter are less than that of the conventional interleaved ZVS forward converter. The operation principle and system analysis of the proposed converter are provided in detail. Experimental results for a 280,W prototype operated at 100,kHz are provided to demonstrate the effectiveness of the proposed converter. Copyright © 2008 John Wiley & Sons, Ltd. [source] Comparison of Two Types of Neonatal Extracorporeal Life Support Systems With Pulsatile and Nonpulsatile FlowARTIFICIAL ORGANS, Issue 11 2009Nikkole Haines Abstract We compared the effects of two neonatal extracorporeal life support (ECLS) systems on circuit pressures and surplus hemodynamic energy levels in a simulated ECLS model. The clinical set-up included the Jostra HL-20 heart,lung machine, either the Medtronic ECMO (0800) or the MEDOS 800LT systems with company-provided circuit components, a 10 Fr arterial cannula, and a pseudo-patient. We tested the system in nonpulsatile and pulsatile flow modes at two flow rates using a 40/60 glycerin/water blood analog, for a total of 48 trials, with n = 6 for each set-up. The pressure drops over the Medtronic ECLS were significantly higher than those over the MEDOS system regardless of the flow rate or perfusion mode (144.8 ± 0.2 mm Hg vs. 35.7 ± 0.2 mm Hg, respectively, at 500 mL/min in nonpulsatile mode, P < 0.001). The preoxygenator mean arterial pressures were significantly increased and the precannula hemodynamic energy values were decreased with the Medtronic ECLS circuit. These results suggest that the MEDOS ECLS circuit better transmits hemodynamic energy to the patient, keeps mean circuit pressures lower, and has lower pressure drops than the Medtronic Circuit. [source] Comparison of Pumps and Oxygenators With Pulsatile and Nonpulsatile Modes in an Infant Cardiopulmonary Bypass ModelARTIFICIAL ORGANS, Issue 11 2009Nikkole M. Haines Abstract As the evidence mounts in favor of pulsatile perfusion during CPB, it is necessary to investigate the effect of circuit components on the quality of pulsatility delivered throughout the circuit. We compared two bloodpumps, the Jostra HL-20 heart-lung machine and the MEDOS DELTASTREAM DP1 Bloodpump, and two oxygenators, the Capiox Baby RX05 and the MEDOS HILITE 800LT, in terms of mean arterial pressure, energy equivalent pressure, surplus hemodynamic energy, total hemodynamic energy, and pressure drop over the oxygenators using a blood analog. The pumps and oxygenators were combined in unique circuits and tested in nonpulsatile and pulsatile modes, at two flow rates (500 and 800 mL/min), and three rotational speed differentials when using the MEDOS DELTASTREAM DP1 Bloodpump for 144 trials in total. The Jostra Roller pump produced some pulsatility in nonpulsatile mode and better pulsatility in pulsatile mode than the MEDOS DP1 Bloodpump at a rotational speed differential of 2500 rpm, but not at 3500 or 4500 rpm. The MEDOS DP1 Bloodpump produced almost no pulsatility in nonpulsatile mode. Pressure drops over the Capiox Baby RX05 were markedly higher, at 92.5 ± 0.4 mm Hg with the MEDOS DP1 Bloodpump at 800 mL/min and 4500 rpm in pulsatile mode, than those of the MEDOS HILITE 800LT oxygenator, which was 67.0 ± 0.1 mm Hg at the same settings. These results suggest that careful selection of each circuit component, based on the individual clinical case and component specifics, are necessary to achieve the best quality of pulsatility. [source] Optimizing the Circuit of a Pulsatile Extracorporeal Life Support System in Terms of Energy Equivalent Pressure and Surplus Hemodynamic EnergyARTIFICIAL ORGANS, Issue 11 2009Choon Hak Lim Abstract:, The nonpulsatile blood flow obtained using standard cardiopulmonary bypass (CPB) circuits is still generally considered an acceptable, nonphysiologic compromise with few disadvantages. However, numerous reports have concluded that pulsatile perfusion during CPB achieves better multiorgan response postoperatively. Furthermore, pulsatile flow during CPB has been consistently recommended in pediatric and high-risk patients. However, most (80%) of the total hemodynamic energy generated by a pulsatile pump is absorbed by the components of the extracorporeal circuit and only a small portion of the pulsatile energy is delivered to the patient. Therefore, we considered that optimizations of CPB unit and extracorporeal life support (ECLS) system circuit components were needed to deliver sufficient pulsatile flow. In addition, energy equivalent pressure, surplus hemodynamic energy, and total hemodynamic energy, calculated using pressure and flow waveforms, were used to evaluate the pulsatilities of pulsatile CPB and ECLS systems. [source] | ||||||||||