Induction motor diagnosis by advanced notch FIR filters and the wigner-ville distribution

During the last years, several time-frequency decomposition tools have been applied for the diagnosis of induction motors, for those cases in which the traditional procedures, such as motor current signature analysis, cannot yield the necessary response. Among them, the Cohen distributions have been widely selected to study transient and even stationary operation due to their high-resolution and detailed information provided at all frequencies. Their main drawback, the cross-terms, has been tackled either modifying the distribution, or carrying out a pretreatment of the signal before computing its time-frequency decomposition. In this paper, a filtering process is proposed that uses advanced notch filters in order to remove constant frequency components present in the current of an induction motor, prior to the computation of its distribution, to study rotor asymmetries and mixed eccentricities. In transient operation of machines directly connected to the grid, this procedure effectively eliminates most of the artifacts that have prevented the use of these tools, allowing a wideband analysis and the definition of a precise quantification parameter able to follow the evolution of their state. © 1982-2012 IEEE

How should we ‘care’ for LGBT+ students within higher education?

This article draws on a recent U.K. research project about lesbian, gay, bisexual and trans (LGBT+) perspectives on university to examine the implications for pastoral care and other service provision on campus. In a departure from previous scholarship that has tended to understand LGBT+ students as ‘vulnerable’ and/or needing ‘support’, it argues that university spaces should be (re)framed in a way that moves beyond (only) personal or individual ‘care’. The article outlines some of the issues that LGBT+ students may face under the following headings: Curriculum and course content; Discrimination, prejudice and bullying; Facilities and service provision on campus; A continuum of experiences. Following these, a final section draws some conclusions and implications for practice in higher education

Application of the Wigner-Ville distribution for the detection of rotor asymmetries and eccentricity through high-order harmonics

The diagnosis of induction machines through the use of methods based on the study of the startup current has become an issue of special interest. These techniques may provide, in certain situations (unbalanced supply voltages, load torque oscillations, variable load, etc.) and for certain faults (broken bars, eccentricity, stator short circuit, etc.) substantial advantages in comparison with the classical method, based on the Fourier spectrum of the steady-state current. Nevertheless, in the case of rotor asymmetries, these transient-based techniques have been mainly focused on the tracing of the lower sideband harmonic (LSH). In this paper, a wideband diagnosis method is proposed, in which the Wigner-Ville distribution is applied to the detection of eccentricity and other high-order components also introduced by the rotor asymmetry. It is shown that the proposed wide band analysis might help to reach a more reliable diagnosis conclusion in cases in which the tracing of commonly used harmonics may be difficult (inter-bar currents, load torque oscillations, non stationary regimes, etc.). An evaluation of the method is carried out through simulations and laboratory tests. The results show the potential of the tool for the detection and quantification of these components as a basis to diagnose such faults. © 2012 Elsevier B.V

Síndrome de Ehlers-Danlos y trasplantes de órganos

El Síndrome de Ehlers Danlos (SED) es una enfermedad rara, que afecta el colágeno. Existen pacientes con SED que fallecen prematuramente a causa de muerte súbita y complicaciones cardiovasculares como en el caso del tipo IV. Esto los convierte en potenciales donantes de órganos. También pueden ser posibles receptores. El siguiente estudio tiene como objetivo relevar la información sobre eventos postquirúrgicos en personas con SED y antecedentes de trasplantes de órganos en estos pacientes tanto donantes como receptores.Facultad de Ciencias Médica

Síndrome de Ehlers-Danlos y trasplantes de órganos

El Síndrome de Ehlers Danlos (SED) es una enfermedad rara, que afecta el colágeno. Existen pacientes con SED que fallecen prematuramente a causa de muerte súbita y complicaciones cardiovasculares como en el caso del tipo IV. Esto los convierte en potenciales donantes de órganos. También pueden ser posibles receptores. El siguiente estudio tiene como objetivo relevar la información sobre eventos postquirúrgicos en personas con SED y antecedentes de trasplantes de órganos en estos pacientes tanto donantes como receptores.Facultad de Ciencias Médica

Results of a university experience, comparing face-toface, online and hybrid teaching in a context of Sarscov19

[EN] The irruption of sarscov19 in the spring of 2020 was a challenge for everyone, particularly university teaching, where solutions had to be improvised urgently. Technological resources and online teaching played a fundamental role, and the involvement of students, teachers and administration led to an acceptable outcome. After the first impact of the pandemic, new alternatives compatible with the protocols of social distancing and health security were proposed in the planning for the academic year 2020-2021. As in many other universities, a synchronous hybrid learning (SHL) model was offered at the Universitat Politècnica de València (UPV), combining online learning and face-to-face (F2F) activities. In the SHL model, some students attended classes in-person (the room capacity limited the number according to the minimum distances between people required) and stream for the rest of the students, who followed the class simultaneously. In addition, the classes were recorded to enable their asynchronous use. SHL was only used when the conditions were favourable. Vulnerable teachers were teaching entirely online in their groups. When the number of students in a group was small enough, teaching was fully F2F, maintaining the online option only for vulnerable or confined students. The laboratory practices followed a similar hybrid scheme. The tutorials were attended by email or videoconference, and the exams were preferably in-person, with ad hoc solutions in the cases of confined or vulnerable students. Between February and June 2021, a pilot experience was carried out in the Electricity course of the degree in Electronic Engineering and Industrial Automation at the UPV. Three groups were taught with a different methodology: online, SHL and F2F teaching. Planning, academic resources, and evaluation were the same in the three groups. All three followed active flipped classroom methods. In this paper, the student's academic outcomes and the results of opinion surveys conducted on the activities are presented. Results are analysed in terms of the three groups/methodologies showing reasonable doubts about the SHL model where, the academic results and the student's opinions are significantly lower than the other two methodologies. These results could help to decide the best methodological solution if we had a similar situation in the future.Authors would like to thank the Institute of Education Sciences of the Universitat Politècnica de València (Spain) for supporting the Teaching Innovation Group e-MACAFI and for the financial support through PIME Project PIME 20-21/220 and PIME Project PIME/2018/B25.Tort-Ausina, I.; Gómez-Tejedor, J.; Molina Mateo, J.; Riera Guasp, J.; Meseguer Dueñas, JM.; Martín-Cabezuelo, R.; Vidaurre, A. (2022). Results of a university experience, comparing face-toface, online and hybrid teaching in a context of Sarscov19. IATED. 896-905. https://doi.org/10.21125/edulearn.2022.025889690

Rotor-bar breakage mechanism and prognosis in an induction motor

© 1982-2012 IEEE. This paper proposes a condition-based maintenance and prognostics and health management (CBM/PHM) procedure for a rotor bar in an induction motor. The methodology is based on the results of a fatigue test intended to reproduce in the most natural way a bar breakage in order to carry out a comparison between transient and stationary diagnosis methods for incipient fault detection. Newly developed techniques in stator-current transient analysis have allowed tracking the developing fault during the last part of the test, identifying the failure mechanism, and establishing a physical model of the process. This nonlinear failure model is integrated in a particle filtering algorithm to diagnose the defect at an early stage and predict the remaining useful life of the bar. An initial generalization of the results to conditions differing from the ones under which the fatigue test was developed is studied

Ionoluminescent response of several phosphor screens to keV ions of different masses

We have characterized the ionoluminescent response of several phosphor powder materials when irradiated with ions of different masses H+ ,He+ ,Ar+ accelerated to keV energies. In particular, we have determined the absolute luminosity in terms of the number of photons per incident ion emitted by luminescent screens of Y2O2S:Tb P45, Y3Al5O12 :Ce P46, Y2SiO5 :Ce P47, Y2O3 :Eu P56, and SrGa2S4 :Eu TG-green. Their ionoluminescence has been studied as a function of ion beam energy and current and ion fluency. The energy trend and mass dependence of selected experimental results are compared relative to stopping and range of ions in matter SRIM code predictions.Ministerio de Educación y Ciencia FTN2003-090