42 research outputs found

    Overview of fast on-board integrated battery chargers for electric vehicles based on multiphase machines and power electronics

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    The study provides an extensive overview of on-board integrated chargers for electric vehicles that are based on multiphase (more than three phases) machines and power electronics. A common attribute of all discussed topologies is that they do not require a charger as a separate device since its role is transferred to the already existing drivetrain elements, predominantly a multiphase machine and an inverter. The study demonstrates how additional degrees of freedom that exist in multiphase systems can be conveniently utilised to achieve torque-free charging operation. Therefore, although three-phase (or multiphase) currents flow through machines' stator windings, they do not generate any torque; thus the machines do not have to be mechanically locked. Cost and weight saving is achieved in this way, while the available space is increased. For each topology operating principles are explained, and its control elaborated in detail for both charging and vehicle-to-grid mode. Finally, the validity of theoretical considerations and control algorithms of some of the existing charging solutions is experimentally verified and experimental performance of all discussed topologies is compared

    The contribution of metacognitions and attentional control to decisional procrastination

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    Earlier research has implicated metacognitions and attentional control in procrastination and self-regulatory failure. This study tested several hypotheses: (1) that metacognitions would be positively correlated with decisional procrastination; (2) that attentional control would be negatively correlated with decisional procrastination; (3) that metacognitions would be negatively correlated with attentional control; and (4) that metacognitions and attentional control would predict decisional procrastination when controlling for negative affect. One hundred and twenty-nine participants completed the Depression Anxiety Stress Scale 21, the Meta-Cognitions Questionnaire 30, the Attentional Control Scale, and the Decisional Procrastination Scale. Significant relationships were found between all three attentional control factors (focusing, shifting, and flexible control of thought) and two metacognitions factors (negative beliefs concerning thoughts about uncontrollability and danger, and cognitive confidence). Results also revealed that decisional procrastination was significantly associated with negative affect, all measured metacognitions factors, and all attentional control factors. In the final step of a hierarchical regression analysis only stress, cognitive confidence, and attention shifting were independent predictors of decisional procrastination. Overall these findings support the hypotheses and are consistent with the Self-Regulatory Executive Function model of psychological dysfunction. The implications of these findings are discussed

    A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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    Integrated motor drive and non-isolated battery charger based on the split-phase PM motors for plug-in vehicles

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    A novel integrated motor drive and non-isolated battery charger based on a split-phase permanent magnet (PM) motor is presented and described for a plug-in vehicle. The motor windings are reconfigured by a relay for the traction and charging operation. In traction mode, the motor is like a normal three-phase motor, whereas in the charging mode, after windings reconnection, the system is a three-phase Boost rectifier. One important challenge to use the motor as three inductors in charger circuit is to have it in standstill during the battery charging. Based on the presented mathematical model of a split-phase PM motor, the zero-torque condition of the motor is explained which led to a proper windings reconnection for the charging. Simulation and experimental results of two separate practical systems are provided to verify the proposed integrated battery charger. Some practical limitations and design recommendations are provided to achieve a more realistic practical system

    The efficacy of oral tizanidine in reducing pain after septoplasty

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    Background: A major problem in surgical procedures is postoperative pain. The effectiveness of prescribing preoperative tizanidine in reducing postoperative pain is not clear. The aim of this study was to determine the efficacy of tizanidine as a premedication in reducing pain after septoplasty. Methods: This double blind clinical trial study was performed in 71 patients aged from 18 to 50 years, undergoing septoplastic surgery for the first time, who were classified in ASA (American Society of Anesthesiologists) classes 1 and 2 in the Ear, Nose, and Throat (ENT) Department of Shafa Hospital, in Kerman, Iran from April 2014 to March 2015. Patients were randomly assigned into two groups using numbers from a randomization table. A dosage of 4 mg of tizanidine was administered orally to the patients two hours before the surgery (septoplasty) in the intervention group. In the control group, placebo pills which were 100 mg vitamin B1 were prescribed. The severity of pain was measured and recorded after 4 and 8 hours, and the morning after the surgery. Results: 62 patients (87.32) were male and 9 (12.68) were female. The mean age of the subjects was 24.6±7.5 years. The two groups were similar in regard to age (P=0.54), but the duration of surgery was different in the two groups (P=0.038) and was longer in the group that received tizanidine. The mean of pain was different between the two groups, after 4 hours and was significantly higher in the group that received tizanidine (P=0.043). The mean of pain was not significantly different between the two groups after 8 hours (P=0.95) or one day after surgery (P=0.79). Conclusion: Although some researchers have reported that taking tizanidine before some surgeries may reduce postoperative pain, in this study the administration of tizanidine before surgery was not effective in reducing pain after septoplasty. © 2020 Tehran University of Medical Sciences. All rights reserved

    Performance evaluation of sediment ejector efficiency using hybrid neuro-fuzzy models

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