Transient harmonic torques in induction machines: measurement and impact on motor performance

This paper focuses on the measurement of transient torques produced by the field harmonics in three phase squirrel cage motors and on the assessment of the operating conditions under which these torques might become significant. The paper presents first a model of the induction machine with any stator and rotor phase number and configuration, fed by arbitrary voltage waveforms and taking into account the space harmonics. Then, very much attention is paid to a reliable model validation against actual transient torques measurements. In this sense, the actual and great difficulties of measuring pulsating electromagnetic torques of several hundreds of Hertz are brought into light, the possible measurement techniques are critically reviewed and the solution chosen is discussed. Once the model accuracy has been experimentally confirmed, it is used to carry out a systematic plan of more than 250 simulations under clearly distinct operating conditions on five different motors. The analysis of these simulations yields a main practical conclusion: field harmonics may have (depending on the motor structure) a significant impact on electromagnetic torque, but only during transients characterized by high instantaneous frequencies of the rotor currents. For low slip transients, their impact is negligible. This conclusion is also theoretically justified in the paper.Echeverria Villar, JA.; Martínez-Román, J.; Serrano Iribarnegaray, L. (2012). Transient harmonic torques in induction machines: measurement and impact on motor performance. Electrical Engineering. 94(2):67-80. doi:10.1007/s00202-011-0216-4S6780942White D, Woodson H (1959) Electromechanical energy conversion. Wiley, LondonTaegen F, Hommes E (1972) Das allgemeine Gleichungssystem des Käfigläufermotors unter Berücksichtigung der Oberfelder. Teil I and II. 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IET Electr Power Appl 1(4): 517–531Levi E, Bojoi R, Profumo F, Tolyat HA, Williamson S (2007) Multiphase induction motor drives. A technology status review. IET Electr Power Appl 1(4): 489–516Park RH (1933) Two-Reaction theory of synchronous machines. A.I.E.E. Trans 48:716–730, 1929 and 52:352–355Wallin C, Ling H, Rasool A (2001) Evaluation of torque pulses in industrial applications using the torque sensor TorductorR-s presented at Sensor for Industry conference. Illinois, USANCTE (2011) High dynamic, non contact, rotary torque sensor—Series 2000. http://www.ncte.de/ncte/cms/front_content.php?idcat=27Hübner Berlin (2002) Acc. sensor ACC93, Preliminary leafletDenne A, Rausch H, Freise W (1981) Aufnehmer zur Messung schnell veränderlicher Drehbeschleunigungen und Drehmomente. Technisches-Messen-tm 48: 339–342Hillner L (2002) Hübner Berlin. Notes about ACC93 installation in motor ABB M2AA112 M-4 from Universidad Politecnica de ValenciaSerrano-Iribarnegaray L, Martínez-Román J (2005) Critical review of the analytical approaches accounting for interbar currents and experimental study of ageing in two-speed asynchr. motors for elevator drives. IEE Proc Electr Power Appl 152: 72–80Echeverría-Villar JA (2004) Aplicación de la teoría de los fasores espaciales al estudio de los campos armónicos en los regímenes transitorios de las máquinas asíncronas y sus repercusiones en los pares pulsantes. PhD Th.; Universidad Politécnica de ValenciaOberretl K (1994) Parasitäre synchrone Dreh- und Pendelmomente in Asynchronmotoren. Einfluss von Ausgleichsvorgängen und Eisensättigung. Parts I and II. Archiv für Elektrotechnik 77:179–190 and 277–288Oberretl K (1965) Ueber den Einfluss von parallelen Wicklungs- zweigen, Dreieckschaltung, Spulensehnung. Nutzschlitzbreite und Nutenschrägung auf das Drehmoment von Käfigläufermotoren in ETZ-A Bd 86: 619–627Brüderlin R (1921) Ueber eine graphische Zerlegung der Feld-Erregerkurve einer unregelmässigen Mehrphasenwicklung in ihre Einzelwellen. ETZ-Archiv für Elektrotechnik 42: 1093–1096Köhler G, Walther A (1931) Fouriersche Analyse von Funktionen mit Sprüngen, Ëcken und änlichen Besonderheiten. Archiv für Elektrotechnik 25: 747–755Lax F, Jordan H (1940) Über die Fourier-Entwicklung der Felderregerkurve von schrittverkürzen Drehstromwicklungen beliebiger Phasenzhal. Archiv für Elektrotechnik 34: 591–597Stepina J (1979) Einführung in die allgemeine Raumzeiger Theorie der elektrischen Maschinen. Press of University of Kaiserslauter

Funcionamiento psicológico y contexto sociocultural de niños latinos de segunda generación

En Estados Unidos, la población de origen latino es la que presenta una mayor tasa de crecimiento (Stepler & Brown, 2016) y se estima que para el año 2050, un tercio de la población estadounidense será latina (US Census Bureau, 2008). A pesar de esta estimación demográfica, en un reciente estudio metaanalítico en el que se revisaron más de 1000 artículos científicos se estimó que menos de un 3% de los estudios analizados se centraron en el análisis de la situación de los menores de origen latino (Rodriguez & Morrobel, 2004). Asimismo, la comunidad latina parece estar en contacto directo con diversos factores de riesgo, entre ellos el vivir en una situación de extrema adversidad económica y el residir en barrios segregados con elevados índices de violencia y criminalidad (Burr, Mutchler, & Gerst-Emerson, 2013). Al mismo tiempo, los menores presentan la mayor tasa de abandono escolar de todos los grupos minoritarios establecidos en EE.UU y los padres manifiestan a nivel general un pobre nivel de involucración y coordinación con los centros escolares (Leidy, Guerra, & Toro, 2012). Esta situación de alta dificultad socio-económica parece aumentar el estrés familiar, lo que afecta también negativamente al estilo parental de los padres y al desarrollo mental de los niños (Brooks- Gunn, Duncan, & Maritato, 1997). Todas estas características familiares y sociales en su conjunto constituyen un ambiente de riesgo para la salud física y mental de los menores. Por ese motivo, será de suma importancia identificar factores de protección que permitan a los niños afrontar las dificultades inherentes a crecer en un ambiente de dificultad socioeconómica y de pertenencia a un grupo minoritario. Así, en la presente Memoria se pretende describir la situación de las familias de origen dominicano y mexicano en la ciudad de Nueva York, y analizar el efecto protector que distintos factores familiares (parentalidad y apoyo social) e individuales (identidad étnica) pueden ejercer sobre la salud mental de los niños en su primaria infancia..

The microbiota as a modulator of mucosal inflammation and HIV/HPV pathogenesis: From association to causation

Although the microbiota has largely been associated with the pathogenesis of viral infections, most studies using omics techniques are correlational and hypothesis-generating. The mechanisms affecting the immune responses to viral infections are still being fully understood. Here we focus on the two most important sexually transmitted persistent viruses, HPV and HIV. Sophisticated omics techniques are boosting our ability to understand microbiota-pathogen-host interactions from a functional perspective by surveying the host and bacterial protein and metabolite production using systems biology approaches. However, while these strategies have allowed describing interaction networks to identify potential novel microbiota-associated biomarkers or therapeutic targets to prevent or treat infectious diseases, the analyses are typically based on highly dimensional datasets —thousands of features in small cohorts of patients—. As a result, we are far from getting to their clinical use. Here we provide a broad overview of how the microbiota influences the immune responses to HIV and HPV disease. Furthermore, we highlight experimental approaches to understand better the microbiota-host-virus interactions that might increase our potential to identify biomarkers and therapeutic agents with clinical applications

Preliminary Study of the Effects of a Comprehensive Teaching Program, Based on Questioning, to Improve Tactical Actions in Young Footballers

The aim of this study was to analyze the effect of a comprehensive teaching program, based on questioning on decision making, and execution in football. The intervention program, based on teaching games for understanding model and including the application of questioning in a context of modified games, was applied during 21 training sessions. A quasi-experimental study with a prepost design with 18 male football players (M¿=¿10.7 years, SD¿=¿0.6) was developed over 18 weeks. Participants were divided into experimental group (n¿=¿9) and control group (n¿=¿9). A total of 1532 actions were observed (1120 passes and 412 dribbling). Results showed that after applying the intervention program, the players in the experimental group showed better decision making in the pass and dribbling actions, and better execution in the pass action, compared with the players from the control group. These results suggest that the application of questioning in a context of modified games must be taken into account to promote tactical training in young footballers and to improve their tactical behavior

Discursos del alumnado de Ciencias de la Salud de la Universidad de Sevilla vinculados con el género

La formación en género en el ámbito de los estudios universitarios ha demostrado ser no sólo necesaria si no un indicativo de calidad. Esta investigación se centra en el análisis del aprendizaje y la enseñanza en materia de género en la Facultad de Enfermería, Fisioterapia y Podología y sus centros adscritos de la Universidad de Sevilla. Se ha realizado un estudio con metodología cualitativa basado en la Teoría Fundamentada, en el que se han examinado los discursos del alumnado vinculados con el género. Los alumnos y alumnas que habían cursado la asignatura “Género y Salud” en Enfermería, entendían el género como un constructo cultural; el alumnado de Fisioterapia y Podología confundían sexo y género. En cuanto a su primer contacto con el género manifiestan que ha sido en la Universidad. La formación en género es una categoría transversal que produce un cuestionamiento personal, una deconstrucción social con una fundamentación teórica.Gender training in the field of university studies has proved to be not only necessary but also an indication of quality. This research focuses on the analysis of learning and teaching on gender in the Faculty of Nursing, Physiotherapy and Podiatry and its affiliated centers of the University of Seville. A study with qualitative methodology based on Grounded Theory has been carried out, in which discourses of students linked to gender have been examined. The students who had studied the subject "Gender and Health" in Nursing, understood gender as a cultural construct; Physiotherapy and Podology students confused sex and gender. Regarding his first contact with the genre, they state that he has been at the University. Gender training is a transversal category that produces a personal questioning, a social deconstruction with a theoretical foundation

Web environment for updating teacher guides

Trabajo de Fin de Grado en Ingeniería Informática, Facultad de Informática UCM, Departamento de Arquitectura de Computadores y Automática, Curso 2019/2020.El proyecto desarrollado se fundamenta en la creación de un entorno web capaz de gestionar y almacenar guías docentes, en las cuales se describen los aspectos básicos de cada asignatura tales como los créditos, curso, competencias, etc. u otros más variables de curso en curso como profesores, horarios o tutorías. El trabajo está principalmente ideado para la Facultad de Ciencias Físicas de la Universidad Complutense de Madrid, aunque se han analizado diferentes fichas docentes de otras facultades para incluir más información de modo que sea adaptable para cualquier facultad que lo necesite. La aplicación consigue gestionar, con un interfaz sencillo, usuarios con diferentes permisos para que puedan completar la plantilla que se les proporciona para las guías, de forma que cada uno redacte la información de la cual es competente y permita al coordinador de la titulación verificar los cambios realizados. Una vez verificados, serán almacenadas en una base de datos y generadas las fichas en los formatos necesarios para su publicación.The project developed is based on the creation of a web environment capable of managing and storing teaching guides, whose basic aspects of each subject are described such as credits, course, competences, etc. or other more variables as teachers, schedules, tutorials, etc.. The work is mainly designed for the Faculty of Physical Sciences of the Complutense University of Madrid, although different teaching files from other Faculties have been analyzed to include more information to be adjustable for any Faculty that needs it. The application can manage, with a simple interface, users with different permissions to complete the template provided for the guides, in order to write the information which, they are competent and allows the degree coordinator to verify the changes made. Once verified, they will be stored in a database and the guides will be generated in the formats for their publication. In general, the application can manage users with different roles to complete a strict template of the guides and store them in a database.Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEunpu

Levels of physical activity in university students: differences by gender, age and states of change

El objetivo de este estudio fue conocer los niveles de actividad física moderada-vigorosa (AFMV) en estudiantes universitarios. Asimismo, se analizaron los niveles de AF en función del género, edad y los estados de cambio del Modelo Transteórico. 901 estudiantes, 408 hombres y 493 mujeres, cumplimentaron el IPAQ-SF y una pregunta que evaluaba los estados de cambio. Entre los resultados obtenidos, se destaca que el 51.39% de los estudiantes no alcanzan los 30 minutos diarios de práctica de AFMV recomendados por los organismos internacionales, siendo el grado de cumplimiento superior en los hombres. En relación a los estados de cambio, en cuanto a los niveles de AFMV se refiere, se aprecian valores significativamente superiores en los estados de acción y mantenimiento respecto al resto de estados de cambio. Todo ello sugiere pautas de intervención para el desarrollo de programas de intervención que incidan en la promoción de AF en la etapa universitaria.The objective was to analyze the levels of moderate to vigorous physical activity (MVPA) in university students. Likewise, it was analyzed PA levels by gender, age and state of change of the Transtheoretical Model. 901 students, 408 men and 493 women, completed the IPAQ-SF and a question to evaluate the stages of change. Among the results, it highlights that 51.39% of students do not achieve the international recommendations of 30 minutes of MVPA practice per day, with a higher compliance in men. Regarding the states of change, in terms of levels of MVPA is concerned, significantly higher values were seen in the action stage and maintenance stage, compared to other stages of change. This suggests intervention guidelines for the development of intervention programs that affect the promotion of PA in the university stage.peerReviewe

MYC as therapeutic target in leukemia and lymphoma

MYC is a transcription factor that is involved in the expression of many genes. Deregulated MYC is found in about half of human tumors, being more prevalent in hematological neoplasms. Deregulation mechanisms include chromosomal translocation (particularly in lymphoma), amplification, and hyperactivation of MYC transcription. Here we review MYC involvement in the major types of leukemia and lymphoma. MYC rearrangements appear in all Burkitt lymphomas and are common in other lymphoma types, whereas in acute lymphoblastic leukemia, acute myeloid leukemia, lymphoproliferative, and myeloproferative diseases, they are less frequent. However, MYC overexpression is present in all types of hematological malignancies and often correlates with a worse prognosis. Data in leukemia-derived cells and in animal models of lymphomagenesis and leukemogenesis suggest that MYC would be a good therapeutic target. Several MYC-directed therapies have been assayed in preclinical settings and even in clinical trials. First, peptides and small molecules that interrupt the MYC–MAX interaction impair MYC-mediated tumorogenesis in several mouse models of solid tumors, although not yet in lymphoma and leukemia models. Second, there are a number of small molecules inhibiting the interaction of MYC–MAX heterodimers with DNA, still in the preclinical research phase. Third, inhibitors of MYC expression via the inhibition of BRD4 (a reader of acetylated histones) have been shown to control the growth of MYC-transformed leukemia and lymphoma cells and are being used in clinic trials. Finally, we review a number of promising MYC-mediated synthetic lethal approaches that are under study and have been tested in hematopoietic neoplasms