1,722,766 research outputs found
Figure data for paper "Robust numerical computation of the 3D scalar potential field of the cubic Galileon model at solar system scales"
No full textThis dataset contains data corresponding to each figure of the paper "Robust numerical computation of the 3D scalar potential field of the cubic Galileon model at solar system scales" in CSV format. It is a postprocessed subset of the full datasets, which are also available
Plotting code for galileon data
No full textMATLAB scripts for plotting the data, used to generate plots for the paper "Robust numerical computation of the 3D scalar potential field of the cubic Galileon model at solar system scales"
Generate plots by running the code in the directory paper_analysis. This calls various plotting tools from the tools directory
Sun-Earth, Sun-Earth-Moon, and idealized system datasets
No full textFull datasets, in .mat format, for the Sun-Earth, Sun-Earth-Moon, and idealized system simulation results used in the paper "Robust numerical computation of the 3D scalar potential field of the cubic Galileon model at solar system scales".
Refer to the enclosed README.txt and reference_manual.pdf for details
Dynamique non-linéaire et stabilité des écoulements micro-capillaires visqueux à surface libres dans rainures triangulaires et sur les surfaces courbes
No full textThe last two decades have brought a revolution in miniaturization of space technology. Thanks to improved microelectronic sensors and MEMS devices, nanosatellites can perform communication and scientific studies previously limited to large satellites, significantly reducing the financial barriers to space access. But development of a reliable, long-running, small-scale propulsion system for orbital maneuvers remains a key challenge. One solution is the microfluidic electrospray propulsion (MEP) thruster under development at NASA's Jet Propulsion Laboratory (JPL).This thesis analytically addresses aspects of the MEP system's propellant management, specifically, capillary flow in the groove network delivering fluid propellant from the reservoir to the emitters. Building upon the reduced-order model of viscous capillary flow in straight V-shaped channels (``V-grooves'') of Weislogel (1996) and Romero and Yost (1996), we prove stability of steady-state and self-similar flows. Because the MEP design requires an electric field above the grooves and further calls for grooves which curve and bend in three dimensions, we extend earlier V-groove models to include these effects, and also perform stability analyses of the new models. The results not only validate the use of V-grooves as a robust propellant delivery system, but also provide a theoretical basis for the design of future microfluidic devices with compact, three-dimensional designs and electric fields.In order to lay the groundwork for future studies of early-time behavior of propellant on emitter tips before the Taylor cone necessary for ion emission is formed, we develop the technique of generalized linear stability analysis (Farrell and Ioannou, 1996) of capillary flow of thin viscous films coating curved surfaces (governed by the equation first developed by Roy and Schwartz, 1997). This methodology was first applied to films coating cylinders and spheres by Balestra et al. (2016, 2018); we instead apply the technique and analyze for the first time a viscous-capillary instability arising on a torus coated with a uniform thin film.Besides the capillary fluid dynamics results, two additional pieces of work are included in the thesis.First, in an unorthodox application of Noether's Theorem to non-Lagrangian gradient flow equations, we show that each variational symmetry of the governing functional induces a constraint on the evolution of the system.Second, to support JPL's efforts to directly detect a "fifth force," we introduce and implement numerical methods for computation of the scalar Cubic Galileon Gravity (CGG) field at solar system scales.Les deux dernières décennies ont apporté une révolution dans la miniaturisation de la technologie spatiale.Grâce à des capteurs microélectroniques et des dispositifs MEMS améliorés, les nanosatellites peuvent effectuer des communications et des études scientifiques auparavant limitées aux grands satellites, réduisant considérablement les barrières financières à l'accès à l'espace. Mais le développement d'un système de propulsion fiable, à longue durée de vie et à petite échelle pour les manœuvres orbitales reste un défi majeur. Une solution est le propulseur microfluidique à électrospray (MEP) en cours de développement au Jet Propulsion Laboratory (JPL) de la NASA.Cette thèse analyse des aspects de la gestion du liquide du système MEP, en particulier le flux capillaire dans le réseau de rainures transportant le fluide du réservoir aux émetteurs. Appuyant sur le modèle d'ordre réduit de l'écoulement capillaire visqueux dans les rainures triangulaires de Weislogel (1996) et Romero et Yost (1996), nous prouvons la stabilité du flux aux états d'équilibre et auto-similaire. Parce que le MEP nécessite un champ électrique au-dessus des rainures, et aussi des rainures qui se courbent et se plient en trois dimensions, nous étendons les modèles de rainures triangulaires pour inclure ces effets, et effectuons aussi des analyses de stabilité des nouveaux modèles. Les résultats valident non seulement l'utilisation des rainures triangulaires comme système de distribution de liquide robuste, mais fournissent aussi une base théorique pour la conception de futurs dispositifs microfluidiques compactes, en trois dimensions, et avec des champs électriques.Afin de jeter les bases d'études futures sur le comportement précoce du liquide sur les pointes d'émetteur avant la formation du cône de Taylor nécessaire à l'émission d'ions, nous développons la technique d'analyse de stabilité linéaire généralisée (Farrell et Ioannou, 1996) du flux capillaire de minces films visqueux recouvrant des surfaces courbes (régis par l'équation développée pour la première fois par Roy et Schwartz, 1997). Cette méthodologie a été appliquée pour la première fois aux films recouvrant des cylindres et des sphères par Balestra et al. (2016, 2018); nous appliquons plutôt la technique et analysons pour la première fois une instabilité visco-capillaire apparaissant sur un tore recouvert d'un film mince uniforme.Outre les résultats des dynamiques des fluides capillaires, on inclut deux études supplémentaires dans cette thèse.Tout d'abord, avec une application non orthodoxe du Théorème de Noether à des équations du flot de gradient non lagrangiennes, nous montrons que chaque symétrie variationnelle de la fonctionnelle gouvernante induit une contrainte sur l'évolution du système.Deuxièmement, pour soutenir les efforts du JPL pour détecter directement une "cinquième force", nous introduisons et implémentons des méthodes numériques pour le calcul du champ scalaire de Gravité du Galileon Cubique (CGG) à l'échelle du système solaire
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
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
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