1,720,957 research outputs found
Modelado de la segregación en un proceso de transporte : modelo del continuo
Get PDFEl problema de mezcla de soluciones en procesos de transporte advectivo dispersivo reactivo es de mucho interés en la actualidad, como lo demuestra la abundante bibliografía existente. Se presenta un modelo del continuo simple y eficiente para un proceso de transporte reactivo que incorpora la falta de homogeneidad a escala poral mediante un término que describe las variaciones de concentración a escalas pequeñas, donde se deben ajustar los parámetros libres: tasa de reacción efectiva, que incluye la segregación, y los coeficientes de dispersión. Aplicamos el modelo a dos casos ampliamente estudiados en la literatura, lo que nos permitió ajustar los parámetros. Comparando nuestro trabajo con otras propuestas recientes, los resultados son similares y algunos detalles no menores son superiores.Fil: Cuch, Daniel Alejandro. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina
Two-Dimensional Continuous Model in Bimolecular Reactive Transport
Get PDFRevista con referatoFil: Cuch, Daniel Alejandro. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Rubio, Diana. Universidad Nacional de San Martín. Centro de Matemática Aplicada; Argentina.Fil: El Hasi, Claudio. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: El Hasi, Claudio. Universidad Argentina de la Empresa. Facultad de Ingeniería. Departamento de Ciencias Básicas; Argentina.En este trabajo, se propone un modelo continuo 2D para estudiar la interacción en la interfaz de los procesos de transporte reactivo en medios porosos. El análisis de la segregación producida por una deficiente homogeneización de reactivos a escala porosa se aborda mediante un modelo heurístico paramétrico que considera el gradiente relativo de las especies reaccionantes involucradas en el proceso. Las microindiferencias se incorporan mediante coeficientes de dispersión mecánica longitudinales y transversales. Se considera un modelo continuo bidimensional para el transporte reactivo bimolecular, donde los parámetros de modelado se estiman numéricamente a partir de datos experimentales. Se observa un efecto competitivo entre la segregación y la dispersión, que se analiza mediante experimentos numéricos. El modelo bidimensional reproduce adecuadamente tanto la masa total del producto como su incremento con la velocidad de flujo y la inhomogeneidad del frente de avance. La metodología empleada es sencilla y rápida, y los resultados numéricos presentados aquí indican su eficacia.In this work, a continuum 2D model is proposed to study the interaction at the interface of reactive transport processes in porous media. The analysis of the segre-gation produced by a poor reactant homogenization at poral scale, is addressed by a parametric heuristic model that considers the relative gradient of the reacting spe-cies involved in the process. The micro inhomogeneities are incorporated by means of longitudinal and transversal mechanical dispersion coefficients. A two-dimensional continuous model for the bimolecular reactive transport is consid-ered were modelling parameters are estimated numerically from experimental data. A competitive effect between segregation and dispersion is observed that is analysed by means of numerical experiments. The two-dimensional model reproduces properly both the total mass of the product as well as its increase with the velocity of flow and the inhomogeneity of the advance front. The methodology used is sim-ple, fast and the numerical results presented here indicate its effectiveness.Neste trabalho, um modelo 2D contínuo é proposto para estudar a interação na interface de processos de transporte reativo em meios porosos. A análise da segregação produzida por uma homogeneização deficiente de reagentes em escala porosa é abordada por um modelo heurístico paramétrico que considera o gradiente relativo das espécies reagentes envolvidas no processo. As microinomogeneidades são incorporadas por meio de coeficientes de dispersão mecânica longitudinal e transversal. Um modelo contínuo bidimensional para o transporte reativo bimolecular é considerado, no qual os parâmetros de modelagem são estimados numericamente a partir de dados experimentais. Um efeito competitivo entre segregação e dispersão é observado, o qual é analisado por meio de experimentos numéricos. O modelo bidimensional reproduz adequadamente tanto a massa total do produto quanto seu aumento com a velocidade do fluxo e a não homogeneidade da frente de avanço. A metodologia utilizada é simples, rápida e os resultados numéricos aqui apresentados indicam sua eficácia
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
Enseñanza virtual durante la pandemia, un curso de Física elemental
Get PDFRevista con referatoFil: Vigh, Carlos D. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Vigh, Carlos D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Interdisciplinaria Aplicada; ArgentinaFil: Bortule, María Victoria. Universidad Nacional de General Sarmiento. Instituto de Industria; ArgentinaFil: Scagliotti, Ariel Fabricio. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Frisco, Adriana. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Corvalán, Darío. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.Fil: Cuch, Daniel Alejandro. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina.El contexto de la pandemia mundial de COVID-19 ocasionó un cambio abrupto y repentino de la modalidad de trabajo y estudio en la mayoría de los países. En particular, a nivel educativo fue necesario rápidamente pasar a una modalidad virtual para poder sostener la continuidad pedagógica. En este trabajo se exponen las estrategias utilizadas en tres comisiones de Introducción a la Física de la Universidad Nacional de General Sarmiento. Para ello, se ofrecieron clases virtuales, tanto sincrónicas como asincrónicas, y todas ellas se subieron a YouTube para la utilización de los estudiantes. El uso de esta plataforma permitió tener un registro detallado de la actividad de los usuarios relacionada con estos videos, los cuales pudieron ser contrastados y comparados con los registros de asistencia de las actividades de evaluación. La experiencia fue exitosa por la rápida adaptación de contenidos, siendo bien recibida por los estudiantes logrando un grado de interacción satisfactorio entre docentes y estudiantes y obteniendo resultados similares a los de la cursada presencial histórica.The context of the global COVID-19 pandemic caused an abrupt and sudden change in the modality of work and study in most countries. Specifically, at an educational level, it was necessary to quickly move to a virtual modality in order to sustain pedagogical continuity. In this work the strategies used in three commissions of Introduction to Physics of the National University of General Sarmiento are exposed. For this, virtual classes were held, both synchronous and asynchronous, and all of them were uploaded to YouTube for the use of the students. The use of this platform allowed to have a detailed record of activity of the users related to these videos, which could be contrasted and compared with the attendance records of the evaluation activities. The experience was successful due to the rapid adaptation of content, being well received by students, achieving a satisfactory degree of interaction between teachers and students and obtaining results similar with the historical face-to-face course.O contexto da pandemia global da COVID-19 causou uma mudança abrupta e repentina na modalidade de trabalho e estudo na maioria dos países. Em particular, no nível educacional, foi necessário migrar rapidamente para uma modalidade virtual para manter a continuidade pedagógica. Este artigo apresenta as estratégias utilizadas em três aulas de Introdução à Física na Universidade Nacional General Sarmiento. Para tanto, foram oferecidas aulas virtuais, síncronas e assíncronas, e todas elas foram disponibilizadas no YouTube para uso dos alunos. O uso dessa plataforma permitiu um registro detalhado da atividade do usuário relacionada a esses vídeos, que pôde ser contrastada e comparada com os registros de presença das atividades de avaliação. A experiência foi bem-sucedida devido à rápida adaptação do conteúdo, à boa recepção dos alunos, ao alcance de um nível satisfatório de interação entre professores e alunos e à obtenção de resultados semelhantes aos do curso presencial histórico
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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