190 research outputs found

    Erratum: Noninvasive Measurements and FEM Analyses for Estimating the Rotor Bar-Lamination Contact Resistance (IEEE Trans. Ind. Appl. (2021) 57: 1 (208-217) DOI: 10.1109/tia.2020.3028347)

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    In [1], the correct author affiliations should read: Z. Gmyrek is with the Institute of Mechatronics and Information Systems, Lodz University of Technology, Lodz 90-924, Poland (e-mail: [email protected]). S. Vaschetto, M. Ahmadi Darmani, and A. Cavagnino are with the Politecnico di Torino, Dipartimento Energia, Turin 10129, Italy (e-mail: [email protected]; [email protected]; andrea. [email protected])

    Iron Losses and Parameters Investigation of Multi-Three-Phase Induction Motors in Normal and Open-Phase Fault Conditions

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    Among multi-phase solutions, multi-three-phase induction machines (IMs) are gaining an increasing interest in the industry due to their advantages to be configured as multiple three-phase units simultaneously on the same magnetic circuit. According to this scenario, the identification of the equivalent circuit parameters and conventional iron losses covers a key role in evaluating performance and efficiency, especially when the machine is operated in a wide torque-speed range. Therefore, the goal of this paper is to investigate the core losses and the saturation phenomena of multi-three-phase IMs operated in normal and open-three-phase fault conditions under different harmonic contents of the air-gap magnetomotive force. A procedure to identify the parameters of the equivalent circuit of the machine in faulty conditions is reported. Experimental results are presented on a 12-phase asymmetrical IM featuring a quadruple three-phase stator winding. Finally, a comparison between normal and faulty conditions in terms of efficiency and losses for several machine working points is reported

    Superconductivity and its Application in the Field of Electrical Machines

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    This paper provides a review on the most recent applications of superconductors in rotating electrical machines. The main types of superconductors for the present-day electrical applications are shown to highlight their main features. The main characteristics of superconducting synchronous machines, DC machines and induction machines for marine and vehicle propulsion, future electric aircraft, wind energy and industrial applications are discussed by presenting data of prototypes and demonstrators. The paper aims to raise awareness among researchers and engineers on the importance of superconductivity to enhance the performance of conventional electrical machines

    Experimental Assessment of Cryogenic Cooling Impact on Induction Motors

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    In this work, an experimental assessment of the influence of cryogenic cooling in a conventional induction motor is presented. The performance of a fractional kilowatt induction motor is evaluated when submerged in liquid nitrogen. Using the single-phase equivalent electric circuit, the influence of the temperature and skin-effect is analyzed in the variation of the machine's parameters, under ambient and cryogenic conditions. Also, the variation of the iron core and mechanical losses are evaluated. An analytical methodology is proposed to estimate the change of motor performance under cryogenic conditions. For the analyzed induction motor, measurements are performed to verify the predicted machine performance. The experimental tests in cryogenic conditions show the possibility of achieving higher efficiency levels with more than double the nominal torque. Also, due to the cryogenic environment, there was no thermal constraint in the operation of the induction motor

    A multi-site real-time co-simulation platform for the testing of control strategies of distributed storage and V2G in distribution networks

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    © 2016 IEEE and EPE Association. This paper presents a real-time co-simulation platform aimed to test control strategies for the management of the interaction between a smart grid and active prosumers. The main feature of the proposed framework relies on the multi-site approach that allows the decoupling between the network model and the system under test. This allows separate testing with the exchange of a limited amount of information between the two systems, helping to preserve the confidentiality of data belonging to different parties. As an example the paper addresses the development and testing of a distributed storage and vehicle-to-grid management system connected to a real distribution network model

    A Comparison of Cryogenic-Cooled and Superconducting Electrical Machines

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    This paper compares the steady-state operation of air-cooled, cryogenic-cooled and superconducting induction machines. The aim is to investigate the impact of a very low temperature and the influence of a superconducting rotor cage on the performances of standard designed, air-cooled machines. The research work includes a review of the state of the art of cryogenic-cooled and superconducting induction machines for various applications. The performances of the machines are assessed analytically by solving the single-phase equivalent circuit and considering the influence of the temperature, the skin-effect and the nonlinear behavior of superconductors. The analytical results are validated by experiments on a fractional kilowatt induction motor. The experimental activities include the characterization of the core losses at cryogenic temperature

    "war to the knife" against thromboinflammation to protect endothelial function of COVID-19 patients

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    In this viewpoint, we summarize the relevance of thromboinflammation in COVID-19 and discuss potential mechanisms of endothelial injury as a key point for the development of lung and distant organ dysfunction, with a focus on direct viral infection and cytokine-mediated injury. Entanglement between inflammation and coagulation and resistance to heparin provide a rationale to consider other therapeutic approaches in order to preserve endothelial function and limit microthrombosis, especially in severe forms. These strategies include nebulized heparin, N-acetylcysteine, plasma exchange and/or fresh frozen plasma, plasma derivatives to increase the level of endogenous anticoagulants (tissue factor pathway inhibitor, activated protein C, thrombomodulin, antithrombin), dipyridamole, complement blockers, different types of stem cells, and extracellular vesicles. An integrated therapy including these drugs has the potential to improve outcomes in COVID-19

    Modulating signaling networks by CRISPR/Cas9-mediated transposable element insertion

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    In a recent past, transposable elements (TEs) were referred to as selfish genetic components only capable of copying themselves with the aim of increasing the odds of being inherited. Nonetheless, TEs have been initially proposed as positive control elements acting in synergy with the host. Nowadays, it is well known that TE movement into host genome comprises an important evolutionary mechanism capable of increasing the adaptive fitness. As insights into TE functioning are increasing day to day, the manipulation of transposition has raised an interesting possibility of setting the host functions, although the lack of appropriate genome engineering tools has unpaved it. Fortunately, the emergence of genome editing technologies based on programmable nucleases, and especially the arrival of a multipurpose RNA-guided Cas9 endonuclease system, has made it possible to reconsider this challenge. For such purpose, a particular type of transposons referred to as miniature inverted-repeat transposable elements (MITEs) has shown a series of interesting characteristics for designing functional drivers. Here, recent insights into MITE elements and versatile RNA-guided CRISPR/Cas9 genome engineering system are given to understand how to deploy the potential of TEs for control of the host transcriptional activity.Fil: Vaschetto, Luis Maria Benjamin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Cátedra de Diversidad Animal I; Argentin

    SĂ­ntesis y Estudio de Silicatos Mesoporosos Modificados con Boro

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    Se prepararon materiales mesoporosos del tipo B-MCM-41. Se investigó la influencia de la variación del tiempo de tratamiento hidrotérmico, la fuente de hidróxido, el contenido de B, el grado de incorporación del B en la estructura y el carácter ácido del material obtenido. Se confirmó que la acidez de las muestras se debe a los silanoles nido presentes en los defectos estructurales del material sintetizado. Estas especies se generan principalmente por la introducción de B dentro de la estructura y sus propiedades ácidas pueden ser causadas por la presencia del heteroátomo. De esta manera se logró obtener una acidez moderada en los materiales mesoporosos obtenidos, característica muy importante para determinados procesos catalíticos

    High tidal volume mechanical ventilation-induced lung injury in rats is greater after acid instillation than after sepsis-induced acute lung injury, but does not increase systemic inflammation: an experimental study

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    <p>Abstract</p> <p>Background</p> <p>To examine whether acute lung injury from direct and indirect origins differ in susceptibility to ventilator-induced lung injury (VILI) and resultant systemic inflammatory responses.</p> <p>Methods</p> <p>Rats were challenged by acid instillation or 24 h of sepsis induced by cecal ligation and puncture, followed by mechanical ventilation (MV) with either a low tidal volume (Vt) of 6 mL/kg and 5 cm H<sub>2</sub>O positive end-expiratory pressure (PEEP; LVt acid, LVt sepsis) or with a high Vt of 15 mL/kg and no PEEP (HVt acid, HVt sepsis). Rats sacrificed immediately after acid instillation and non-ventilated septic animals served as controls. Hemodynamic and respiratory variables were monitored. After 4 h, lung wet to dry (W/D) weight ratios, histological lung injury and plasma mediator concentrations were measured.</p> <p>Results</p> <p>Oxygenation and lung compliance decreased after acid instillation as compared to sepsis. Additionally, W/D weight ratios and histological lung injury scores increased after acid instillation as compared to sepsis. MV increased W/D weight ratio and lung injury score, however this effect was mainly attributable to HVt ventilation after acid instillation. Similarly, effects of HVt on oxygenation were only observed after acid instillation. HVt during sepsis did not further affect oxygenation, compliance, W/D weight ratio or lung injury score. Plasma interleukin-6 and tumour necrosis factor-α concentrations were increased after acid instillation as compared to sepsis, but plasma intercellular adhesion molecule-1 concentration increased during sepsis only. In contrast to lung injury parameters, no additional effects of HVt MV after acid instillation on plasma mediator concentrations were observed.</p> <p>Conclusions</p> <p>During MV more severe lung injury develops after acid instillation as compared to sepsis. HVt causes VILI after acid instillation, but not during sepsis. However, this differential effect was not observed in the systemic release of mediators.</p
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