1,720,954 research outputs found
Low flow mixing in open channels
No full textIn problems involving water quality and pollution in natural streams under low flow conditions, during which pollution problems are most acute, a complete understanding of the effects of variations of flow and channel geometry on mixing and transport of polluted releases is necessary to establish sound water pollution control programs as well as water resources management programs.In this research, a systematic and comprehensive study of the effects of variations of flow and channel geometry on mixing and transport of polluted releases in natural streams under low flow conditions has been conducted. The non-Fickian nature of the low flow mixing in natural channels has been investigated using both laboratory experiments and the numerical solution of the proposed mathematical model which is based on a set of mass balance equations describing the mixing and mass exchange mechanisms, in which the effect of channel storage zones was included.Laboratory experiments, which involved collection of channel geometry, hydraulic, and dye dispersion test data, were conducted to obtain sets of experimental data on a model of four pool and riffle sequences in a 161-ft long tilting flume in the Hydrosystems Laboratory at the University of Illinois at Urbana-Champaign. The experimental results indicate that the flow over the model pool-riffle sequences is highly non-uniform. Concentration-time curves are significantly skewed with long tails. The measured dispersion coefficients and the mass exchange coefficients are close to those measured by previous investigators.The mixing and dispersion in the laboratory channel was simulated using a numerical solution of the proposed mathematical model in which the 6-point finite difference method developed by Stone and Brian was used as a solution technique. The comparison between the measured and predicted concentration-time curves shows that there is a good level of agreement in the general shape, peak concentrations and time to peak. The proposed model shows significant improvement over the conventional Fickian model in predicting the dispersion process in natural channels under low flow conditions.Made available in DSpace on 2011-05-07T13:28:26Z (GMT). No. of bitstreams: 2
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Behavior of Air Bubble Screens (HES 33)
No full textnot peer reviewedSubmitted by Nils Oberg ([email protected]) on 2009-06-15T18:34:45Z
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Previous issue date: 1978-09National Science Foundation Grant ENG-76-24226unpublishe
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
Measurements in Intersecting Submerged and Induced Jets (HES 34)
No full textnot peer reviewedSubmitted by Nils Oberg ([email protected]) on 2009-06-15T18:40:56Z
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Previous issue date: 1979-08National Science Foundation Grant ENG-76-24226 A01unpublishe
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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