1,720,954 research outputs found
Advanced characterization with multimodal measurement techniques for process intensification in gas–liquid tubular reactors
Full text linkIn this work we investigate turbulent gas–liquid mixing and separation in a vertical pipeline equipped with Kenics Static Elements for process intensification applications in continuous operations. The investigation is based on Electrical Resistance Tomography, digital image analysis and pressure drop measurements to provide a comprehensive characterization of the two-phase system. The gas volume fraction distribution is calculated from the voltage difference measurement using two different reconstruction algorithms: the Sensitivity Conjugate Gradient and the Linear Back Projection. The Sensitivity Conjugate Gradient algorithm provides better resolution near the pipe wall and a clear detection of the asymmetric patterns typical of the helical elements. The bubble size distributions obtained from digital image analysis allow to assess the effectiveness of the static elements in providing mixing and separation, depending on their orientation. The spatial distributions of the gas phase measured by the optical and the tomographic techniques are adopted to obtain the average gas hold-up leading to similar results. Overall, the experimental data analysis demonstrates that optimal performance can be determined by balancing energy consumption and gas dispersion. The findings provide valuable insights for the design of in-line reactors where both efficient mixing and controlled separation are required
Evaluation of synthetic jet flow control technique for modulating turbulent jet noise
No full textilustraciones, graficasEn esta tesis se estudia el uso la técnica de control activo tipo chorro sintético en un chorro circular turbulento con Reynolds de 11e10^3 y Mach 0.1 usando simulaciones numéricas. Para determinar el efecto de aplicar la técnica de control se calcularon diferentes estadísticas turbulentas y la respuesta acústica del flujo en el campo lejano. Se utilizó la estrategia de simulación de efectos turbulentos UDNS (Under-resolved Direct Numerical Simulation) y posteriormente usando la analogía acústica de FWH (Ffowcs-Williams and Hawkings) se determinó la respuesta acústica en el campo lejano. Se realizaron simulaciones utilizando diferentes valores de operación del chorro sintético y se compararon con el caso canónico del chorro turbulento. Desde el punto de vista de la modulación de la turbulencia, se observó que dependiendo de los parámetros de operación del chorro sintético se puede incentivar la aparición de inestabilidades cerca de la boquilla, que aceleran el proceso de producción y disipación de la energía cinética turbulenta, u obtener una respuesta similar al caso canónico. Sin embargo, desde el punto de vista de la respuesta acústica en el campo lejano, se observó la aparición de un tono puro en los espectros de ruido con una frecuencia de 0.5 la frecuencia de oscilación del chorro sintético, el cual varia su amplitud para diferentes ángulos de medición. (Texto tomado de la fuente)In this thesis we study the use of the synthetic jet active control technique in a turbulent round jet with Reynolds of 11e10^3 and Mach 0.1 using numerical simulations. To determine the effect of applying the control technique different turbulent statistics and the acoustic response of the far-field were calculated. The UDNS (Under-resolved Direct Numerical Simulation)turbulent effects simulation strategy was used and then using the FWH (Ffowcs-Williams and Hawkings) acoustic analogy, the far-field acoustic response was determined. Simulations were performed using different operating values of the synthetic jet and compared with the canonical case of the turbulent jet. From the point of view of turbulence modulation, it was observed that depending on the operating parameters of the synthetic jet, instabilities near the nozzle, which accelerate the process of production and dissipation of turbulent kinetic energy, can be encouraged or a similar response to the canonical case can be obtained. However, from the point of view of the acoustic response in the far field, a pure tone was observed in the noise spectra with a frequency of 0.5 the oscillation frequency of the synthetic jet, which varies in amplitude for different measurement angles.MaestríaMagíster en Ingeniería MecánicaDinámica de fluidos computacional y Aeroacustic
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
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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