1,720,957 research outputs found
Optimización de la geometría externa de la buza del molde para colada continua de planchón de acero
Full text link53 páginas. Maestría en Ingeniería de Procesos.Hoy en día, el acero sigue siendo el material de más amplio uso en todas las ramas de la industria, si bien, nuevos materiales se han desarrollado, estos aún no pueden sustituir al acero debido a su amplio rango de propiedades mecánicas que puede ofrecer, además en los últimos años se han seguido desarrollando diversos tipos de aceros como los aceros de alta resistencia de última generación como TRIP, TWIP y DP que permiten una reducción de peso considerable en aplicaciones estructurales. Es por esta razón que el proceso de colada continua sigue siendo de importancia fundamental en la industria. De aquí que la mejora de la calidad del proceso de colada continua sea fundamental. Los defectos que afectan de manera importante la calidad del acero son las inclusiones no metálicas causadas durante el vaciado en el molde de CC por arrastre de escoria. Para disminuir este defecto se han propuesto distintas alternativas como el uso del freno electromagnético. El problema del freno electromagnético es que resulta costoso y difícil de operar. En este trabajo se propone una solución simple y de bajo costo que según veremos resulta eficiente para disminuir el arrastre de escoria. Si bien, hace falta más investigación para su implementación, los resultados obtenidos durante la investigación aportan evidencia de que desde el punto de vista de la mecánica de fluidos es posible su uso. La solución aquí presentada consiste en el uso de un deflector de flujo externo rectangular que forma parte de la buza bifurcada, que tiene como intención provocar un patrón de flujo cuasi simétrico que impida la formación de fluctuaciones, las cuales, a su vez, son las responsables en gran medida del arrastre de escoria que puede generar defectos internos o superficiales en el acero durante su solidificación después del vaciado en el molde de CC
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Evaluación del desempeño aerodinámico mediante una técnica experimental aplicada a envolventes arquitectonicas
Full text link193 páginas. Maestría en Diseño.A methodology to analyze the behavior of the flow around an architectural construction in a wind tunnel is presented as a fundamental tool in order to control the operational conditions. The initial work was the characterization of the wind tunnel to scale the physical models and was defined as 1:50. The material used in the construction of the scaled models is translucent acrylic of 0.003 meters thick. Materials selection was based on the optical properties of the selected material that facilitates the visualization of the air flow in the test area of the wind tunnel. All models was positioned on a base built in acrylic. The assembly was placed on a glass with a 0.005 meters of thickness; the structure has adjusted to the width of the tunnel to avoid the influence of the internal walls, to construct a plane to facilitate the visualization and moreover the interpretation of the results. The selection of the light source is one of the innovations presented on this thesis. Basically, the plane of light is near 0.0005 meters thick, that defines a region around the control volume in order to study only one plane. The three dimensional nature of the flow around a geometry phenomenon is complex. However, it is possible to study by using the proposed experimental technique and a high speed camera at different operational conditions. One of the objectives in this work is to ensure the reproducibility of the test base on the geometric, kinematic and dynamic similarity criteria. It is possible to consider the as non-intrusive technique; moreover it is possible to study the qualitative nature of the fluid around a building, to propose several bioclimatic designs of architectural geometries and to evaluate the cases within the wind tunnel. The interpretation of the results highlights the advantages of the method over the conventional visualization techniques. It is also consider as a tool that can be used in scaled models.En la presente tesis se presenta una metodología de análisis para el comportamiento del flujo en los alrededores de una envolvente arquitectónica en donde se utiliza un túnel aerodinámico como herramienta fundamental para controlar las condiciones de las pruebas. La caracterización del túnel aerodinámico fue el punto de partida para proponer la escala de los modelos físicos. La escala de los modelos es 1:50, el material utilizado para la elaboración de las representaciones a escala es acrílico translucido de 0.003 metros de espesor. La selección del material fue basado en las propiedades ópticas que favorecen la visualización del flujo de aire en la zona de pruebas. Todos los modelos están montados en una base también construida en acrílico. El conjunto se colocó sobre una base de vidrio de 0.005 metros de espesor graduada al ancho de la vivienda con la finalidad de formar un plano sobre la envolvente que facilitara la interpretación de los resultados. La selección de la fuente de iluminación es una de las innovaciones que se realizaron en esta tesis, si se compara con los resultados reportados en la literatura especializada. La iluminación en general es un plano de luz de espesor cercano a 0.0005 metros que delimita una región en los alrededores del volumen de control con la finalidad de estudiar únicamente un plano. La naturaleza tridimensional del fenómeno de flujo alrededor de una envolvente es compleja, sin embargo la técnica experimental permite estudiar con la ayuda de una cámara de alta velocidad las diferentes condiciones del flujo en un instante de tiempo. Después de garantizar la reproducibilidad de las pruebas asegurando la semejanza geométrica, cinemática y dinámica en su conjunto, es posible afirmar que la técnica no se considera intrusiva y permite estudiar con precisión el comportamiento cualitativo de las propuestas de diseño dentro del túnel. La interpretación de los resultados resalta las ventajas que ofrece la técnica sobre los sistemas de visualización convencionales. Además es una herramienta que puede ser utilizada en modelos en escala real de manera económica y factible
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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