1,720,955 research outputs found
Internal heat transfer coefficient estimation in three-dimensional ducts through the reciprocity functional approach - An analytical approach and validation with experimental data
No full textIn the current paper it is presented and tested an innovative method for estimating internal heat transfer coefficients in ducts adopting only thermal measurements acquired on the external wall surface. This approach is based on the reciprocity functional analysis, which is a powerful non-intrusive inverse problem technique. The adoption of this technique is promising since it avoids intrusive measurements, it is fully non-iterative and the computational time and cost are very limited. In this paper, it is presented an extension of the classical reciprocity functional methodology in the sense that a fully analytical expression, obtained by the integral transform technique, is developed for estimating the internal heat transfer coefficient in a three-dimensional problem. Such methodology, avoiding the solution of linear systems, reduces the computational costs that are massive when the traditional approaches are applied to three dimensional problems. The proposed procedure is first validated adopting synthetic temperature data and then tested using real temperature measurements acquired by an infrared camera. The results highlight that the methodology is able to recover the unknown functions in a very short computational time with a good accuracy
Convection heat transfer coefficient estimation in ducts using the reciprocity functional method
Get PDFIn this work, we present an original inverse problem approach, based on the Reciprocity Functional Method coupled with the Classical Integral Transform Technique. This results in a fully analytical estimation approach, which is applied to a three-dimensional inverse problem to estimate the internal heat transfer coefficient distribution in ducts, using temperature measurements taken on the external boundary of the duct. The methodology allows the use of both steady-state and transient external wall temperature measurements as input data. To estimate the heat transfer coefficient in a duct, according to the proposed technique, two auxiliary problems are required: the first is related to the estimate of the heat flux and the second to the estimate of the internal wall temperature. The convection heat transfer coefficient is therefore calculated, since the heat flux and the internal wall temperature are known. Such innovative methodology, avoiding the solution of linear systems, reduces the computational cost that is considerable when traditional approaches are applied to three-dimensional problems. The proposed procedure is first verified adopting synthetic temperature data and then validated using real temperature measurements acquired by an infrared camera. The results highlighted that the presented methodology is able to recover the unknown functions in a very short computational time and with a good accuracy, even when the noisy temperature measurements are used.Neste trabalho apresenta-se uma abordagem original de problema inverso baseado no Método do Funcional de Reciprocidade, acoplado à Técnica da Transformada Integral Clássica. A abordagem totalmente analítica é aplicada a um problema inverso tridimensional para estimar a distribuição interna do coeficiente de transferência de calor em dutos usando medições de temperatura na superfície externa do duto. A metodologia permite o uso de medições de temperatura de parede externa tanto em regime permanente quanto em transiente como dado de entrada. Para estimar o coeficiente de transferência de calor em um duto na abordagem aqui apresentada, são necessários dois problemas auxiliares: o primeiro está relacionado com a estimativa do fluxo de calor e o segundo com a estimativa da temperatura interna da parede. O coeficiente de transferência de calor por convecção é então calculado, uma vez que o fluxo de calor e a temperatura da parede interna são conhecidos. Tal metodologia inovadora evita a solução de sistemas lineares, reduzindo os custos computacionais que são consideráveis quando as abordagens tradicionais são aplicadas a problemas tridimensionais. O procedimento proposto é inicialmente verificado usando dados sintéticos de temperatura e depois validado usando medições reais de temperatura adquiridas por uma câmera infravermelha. Os resultados evidenciam que a metodologia é capaz de recuperar as funções desconhecidas em um tempo computacional baixo e com uma boa precisão, mesmo quando medidas de temperatura com ruídos são utilizadas
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
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