1,720,970 research outputs found
Desarrollo de una herramienta de modelación matemática acoplada con Técnicas de Vídeo para el estudio de flujos transitorios en tuberías en U y flujos potenciales en una celda Hele Shaw
Get PDFResumen: En esta tesis se ha desarrollado un software para facilitar el proceso de enseñanza-aprendizaje del movimiento oscilatorio amortiguado y forzado en tubos en U, y algunos casos de flujo potencial. El software desarrollado utiliza técnicas de procesamiento de imágenes para procesar los datos experimentales, lo que permite analizar las imágenes obtenidas en laboratorio, y comparar estos resultados con las soluciones teóricas. El error asociado a la técnica de video fue evaluado separando el error sistemático (RMSEs) del error no sistemático (RMSEu). Los máximos RMSEs obtenidos en las pruebas realizadas fueron: 2.2 mm para oscilaciones amortiguadas, 1.27 mm para flujo rectilíneo uniforme y 2.37 mm para flujo alrededor de un cilindro. Estos resultados ratifican el potencial uso de técnicas de video en ambientes de laboratorio para el estudio de las oscilaciones amortiguadas en tuberías en U y de flujos potenciales en la celda Hele Shaw.Abstract: In this thesis a software was developed to facilitate the teaching-learning process for a damped and forced oscillatory movement of a liquidin U-tubes and some cases of potential flow. The software developed uses image processing techniques to process experimental data, allowing the user to analyze the images obtained in the laboratory and to compare these results with theoretical solutions. The error associated with the video technique was evaluated by separating systematic errors (RMSEs) from unsystematic errors (RMSEu). The maximum RMSEs obtained in the tests were: 2.2 mm for damped oscillations, 1.27 mm for uniform linear flow, 2.37 mm for flow around a cylinder. The obtained values of RMSEs confirm the potential of using video techniques in laboratory settings to study the damped oscillations in the U-tube and flows in the cell potential Hele Shaw.Maestrí
Influence of infragravity waves on the hydrodynamics of beaches
Get PDFInfragravity waves behavior on three natural beaches were studied. Swash Oscillations were analyzed trough camera systems on an intermediate beach of Sylt, Germany, and a dissipative beach of Cartagena, Colombia. On the intermediate beach, under calm conditions swash spectra was dominated by Sea-Swell energy, by contrast, under storm conditions, swash spectra was dominated by infragravity energy. A different behavior was observed on the dissipative beach, where under calm conditions infragravity energy dominated the swash spectra. Furthermore, different signatures in the swash spectra saturation were found in both beaches. On the other hand, mechanism of infragravity waves generation and evolution of infragravity energy flux were analyzed on a dissipative beach Costa Verde, Ciénaga, by using traditional methods and introducing the Complete Ensemble Empirical Mode Decomposition (CEEMD) method, which was designed to analysis of aperiodic signals from non-linear and non-stationaries systems. CEEMD method proved superiority describing the energy distribution at the IG band. Furthermore, analysis with both methods, suggest that Bound Long Wave (BLW) was the main source of IG energy, showing that BLW release occurred before the Sea-Swell wave breaking. Moreover, seaward and shoreward energy flux variation were analyzed finding that the behavior in the infragravity band was different between lower and higher infragravity periods, also was observed that linear energy fluxes were the main source of infragravity energy.Resumen: el comportamiento de las ondas infragravitatorias fue estudiado en tres playas naturales. Las Oscilaciones de Swash fueron analizadas a través de sistemas de cámaras en una playa intermedia de Sylt, Alemania, y una playa disipativa de Cartagena, Colombia. En la playa intermedia, bajo condiciones de calma, el Espectro de Swash fue dominado por la energía de Sea-Swell, por el contrario, bajo condiciones de tormenta, el Espectro de Swash fue dominado por la energía infragravitoria. Un comportamiento diferente fue observado en la playa disipativa, donde bajo condiciones de calma, la energía infragravitatoria domino el Espectro de Swash. Además, diferentes características en la saturación del Espectro de Swash fueron observadas en ambas playas. Por otra parte, fueron analizados los mecanismos de generación de las ondas infragravitatorias y la evolución de los flujos de energía infragravitatoria, en una playa disipativa en Ciénaga, Colombia, usando métodos tradicionales e introduciendo el método Complete Ensemble Empirical Mode Decomposition (CEEMD), el cual fue diseÏado para el análisis de señales no periódicas de sistemas no lineales y no estacionarios. El método CEEMD demostró superioridad en describir la distribución de energía en la banda infragravitatoria. Además, el análisis con ambos métodos, sugirió que la onda forzada fue la principal fuente de energía infragravitatoria, mostrando que la liberación de la onda forzada ocurre antes de la rotura de las ondas de Sea-Swell. Además, fueron analizados los flujos de energía hacia el mar y hacia la costa, encontrando que el comportamiento en la banda infragravitatorias fue diferente entre los altos y bajos periodos infragravitatorias. También fue observado que los flujos lineales fueron la principal fuente de energía infragravitatoria.Maestrí
Dinámica oceanográfica del golfo de Urabá y su relación con los patrones de dispersión de contaminantes y sedimentos.
Get PDFSe presenta la descripción general de los patrones de circulación en el golfo de Urabá, la explicación de los patrones de variabilidad de la pluma del rio Atrato y la identificación de los factores principales que afectan la circulación en el golfo. Se evalúo los patrones de dispersión de contaminacion al interior del golfo de Urabá, para lo cual se explicó el patrón de circulación del golfo mediante la utilización de modelos numéricos, calibrados y validados con los datos obtenidos de seis campañas de medición en las que se tomaron perfiles de salinidad y temperatura.Doctorad
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
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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