1,720,955 research outputs found
Modelado de atenuación-dispersión en medios elásticos 2D mediante análisis de ondas compresionales y de cizalla
Get PDFInvestigaciones recientes han mostrado que la tendencia que presenta el método de prospección sísmica en cuanto a extraer propiedades cuantitativas roca-fluido a partir de ondas sísmicas, es muy importante en la exploración de hidrocarburos. Al analizar los fenómenos de atenuación y dispersión es posible obtener información útil relacionada con propiedades físicas de las rocas (porosidad, permeabilidad) y de los fluidos (tipo de fluido, saturación). El presente trabajo estudia la atenuación y dispersión de ondas sísmicas de corte y compresionales al propagarse a través de medios porosos saturados homogéneos y heterogéneos, a partir de modelamiento analítico y numérico, donde el modelamiento numérico se solucionó por el método de elementos finitos en el dominio espacio-frecuencia. Ambos modelamientos se basaron en la Teoría de Biot para medios homogéneos y la Teoría de White para medios heterogéneos. Los experimentos analíticos y numéricos se realizaron para dos areniscas (no fracturadas), arenisca saturada con dos fluidos y una zona de fractura, los cuales mostraron mayores niveles de atenuación y dispersión en zona fracturada, también se evidenció que los altos niveles de atenuación y dispersión de las ondas clásicas están altamente influenciados por la onda compresional lenta.Abstract. Recent research has shown that the tendency which presents the method of seismic prospecting as to extract quantitative rock-fluid properties from seismic waves is very important in hydrocarbon exploration. In analyzing the phenomena of attenuation and dispersion it is possible to obtain useful information related to physical rock properties (porosity, permeability) and fluid (fluid type, saturation). This Thesis studies the attenuation and dispersion of compressional and shear seismic waves to propagate through porous media saturated homogeneous and heterogeneous, from analytical and numerical modeling, where the numerical modeling was solved by the finite-element method in the domain space-frequency. Both modelings were based on the Biot Theory for homogeneous media and the White Theory for heterogeneous media. Analytical and numerical experiments were performed for two sandstones (not fractured), a sandstone saturated with two fluids, and a fracture zone, which showed higher levels of attenuation and dispersion in fractured area, also it showed that high levels of attenuation and dispersion of classical waves are highly influenced by the slow compressional wave.Maestrí
Análisis técnico y recomendaciones para el aprovechamiento del recurso geotérmico disponible en campos de petróleo
No full textLa generación de energía eléctrica a partir del aprovechamiento del recurso geotérmico encontrado en campos de petróleo, es posible debido a la tecnología disponible en plantas binarias o del tipo Organic Rankine Cycle (ORC) en cuanto a la transformación de calor en electricidad. El uso de temperaturas más bajas de agua y mejores eficiencias de las plantas, está permitiendo de aprovechamiento de este recurso geotérmico que antes era inviable tanto técnica como económicamente. El presente documento muestra diferentes fabricantes de plantas binarias (como Climeon, Turboden, Calnetix Technologies, Ormat Technologies Inc.) con eficiencias entre 6% y 14%, para aplicaciones de media a baja temperatura en campos petroleros y sus características técnicas y análisis económico. A partir de datos de temperatura de agua de 82 °C y 88 °C con diferencial de salida de 10°C, y flujo másico de 61 kg/s y 99 kg/s de dos campos petroleros localizados en el Piedemonte Colombiano, se modela y calcula la potencia generada en función de cuatro fluidos de trabajo correspondientes a R123, R245fa, R134a e Isopentano. Los resultados permitieron calcular potencias de aproximadamente 200 kW para la zona 1 y 320 kW para la zona 2. El fluido de trabajo que mejores resultados aportó fue el Isopentano al considerar los valores más bajos de presión de evaporación y flujo másico de fluido de trabajo, además de la mayor potencia generada. Finalmente, se concluye que es posible implementar la tecnología de plantas binarias para la generación de energía eléctrica a partir de las aguas calientes obtenidas en campos petroleros colombiano
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
