1,720,964 research outputs found
Diseño y simulación del rotor de imanes permanentes para el generador síncrono de una turbina eólica de baja potencia
Get PDFEl siguiente proyecto consiste en diseñar y modelar un aerogenerador de eje vertical de 1kW. Como aerogenerador de clase S, con una velocidad esperada 5 m/s. El rendimiento se evalúa en un patrón de viento previamente registrado alrededor de 3 m/s en una locación ubicada en Guadalajara, esperando también explorar otros lugares en donde el viento pueda hacerlo funcionar. Con el objetivo de llegar a los mejores rendimientos aerodinámico, se selecciona un aerogenerador de eje vertical de cuatro palas.
El generador eléctrico se considera como máquina síncrona trifásica de imanes permanentes con un rotor externo y la capacidad de convertir hasta 1 kW de potencia mecánica gracias al eje de acoplamiento directo con el rotor eólico, también se pretende alcanzar una velocidad nominal de 175 RPM con una eficiencia del 85% y un par nominal de 70 Nm. Ya que este prototipo está planeado para ser conectado a la red a 120 VAC por un solo convertidor de fuente de tensión diseñado hasta 1.5 kW, una potencia nominal se espera un voltaje de salida de línea a línea de 45 VCA en la salida generador eólico, siendo rectificado ganando un voltaje nominal de bus de CC de 60 VDC, que se puede aumentar hasta 240 VDC a través de un DC-DC convertidor de carga.The following project consists of designing and modeling a 1kW vertical axis wind turbine. As a class S wind turbine, it has an expected speed of 5 m/s. The performance is evaluated in a previously recorded wind pattern around 3 m/s in a location located inuadalajara, hoping to also explore other places where the wind can make it work. Inorder to achieve the best aerodynamic performance, a four-blade vertical axis wind urbine is selected.
The electric generator is considered as a three-phase permanent magnet synchronous machine with an external rotor and the ability to convert up to 1 kW of mechanical power thanks to the direct coupling shaft with the wind rotor, it is also intended to achieve a nominal speed of 175 RPM with an efficiency of 85% and a nominal torque of 70 Nm. Since this prototype is planned to be connected to the network at 120 VAC by a single voltage source converter designed up to 1.5 kW, at nominal power a line-to-line output voltage of 45 VAC is expected at the wind generator output, being rectified gaining a nominal DC bus voltage of 60 VDC, which can be increased up to 240 VDC via a DC-DC charge converter
DISEÑO Y CONSTRUCCIÓN DE UN POTENCIOSTATO PARA LA MEDICIÓN DE POTENCIAL, CORRIENTE E IMPEDANCIA PARA CARACTERIZACIÓN ELECTROQUÍMICA DE SUPERFICIES METÁLICAS, EMPLEANDO TARJETA DE ADQUISICIÓN DE DATOS CON CONECTIVIDAD WIFI
Get PDFTradicionalmente, tanto los científicos como los estudiantes de posgrado vinculados a la ciencia y la ingeniería han confiado en costosos equipos de laboratorio para la realización de pruebas electroquímicas. No obstante, en la actualidad, el panorama está experimentando una transformación marcada por la creatividad y la innovación. Cada vez más, se observa un cambio hacia la capacidad de diseñar y construir equipos de laboratorio personalizados, desafiando las limitaciones impuestas por la dependencia de dispositivos costosos. Este impulso hacia la autonomía tecnológica refleja una era en la que la inventiva y la adaptabilidad están redefiniendo las fronteras de la investigación electroquímica, permitiendo a los científicos explorar nuevas posibilidades de manera más accesible y económic
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effect of plasma treatment of copper on its corrosion behaviour in 3.5 % NaCl solution
Get PDFThe influence of plasma preoxidation treatment on the corrosion behaviour of copper in a 3.5 % NaCl solution was evaluated. The electrochemical techniques used included potentiodynamic polarization curves, electrochemical impedance spectroscopy and linear polarization resistance at 20, 40 and 60 °C. The results showed that the preformed oxides included both cupric (CuO) and cuprous oxides (Cu2O). Potentiodynamic polarization curves showed a reduction in the corrosion current density value by one order of magnitude in the plasmaoxidized specimens. However, for longer exposure times, the corrosion rates were higher for the plasma-oxidized specimens. Corrosion rates increased with an increase in the testing temperature. The corrosion mechanism was changed by the plasma treatment since it was under charge control for the as-received specimens, whereas a diffusion-controlled mechanism was active for the plasma-oxidized specimens at temperatures of at least 20 °C
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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