1,720,974 research outputs found
The pressure gradient for heterogeneous flow of coal, sand and iron in pipelines
No full textThe existing relationships based on Durand's method to predict pressure gradients for slurry flow in pipelines appear to be inadequate when accounting for a wide range of variables such as particle size and relative density as well as concentration. Using the coal, sand and iron ore data collected from various literature sources with the aid of non-dimensional analysis, new equations for the case of the heterogeneous flow regime were derived on the base of nondimensional parameters. The equations have the same structure for each material considered, but the coefficients are different.Civil Engineering and Geoscience
Method of Molerus and Wellman to Compute the Pressure Drop of Slurry Transport in Horizontal Pipes
No full textIn the literaturey many methods for the calculation of pipeline hydraulic transport of solids have been published. Their degree of exactness and applicability is variabie and therefore it is hard to the designer to make a convincible decision regarding their practical use. A new concept for the computation of slurry hydraulic transport in horizontal pipes proposed by O. Molerus and P. Wellmann based on numerous measurement data seems to provide a practicle method to predict the head loss in slurry pipeline transport. In this report the new method is introduced and a number of new experimental results to verify the new concept. Furthermore some suggestions are presented te impreve the new methed.Hydraulic EngineeringCivil Engineering and Geoscience
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
Tussentijds verslag betreffende metingen van uitwisselingen tussen rivier en haven
No full textDe sedimentatie in een haven wordt o.a. bepaald door de wateruitwisselingen door de havenmond en de stromingspatronen in de haven. Dit onderzoek beperkt zich in hoofdzaak tot het geval van door entrainment (meeslepen) van water uit het havenbekken in de menglaag tussen de rivier en het havenbekken veroorzaakte uitwisseling. Afgezien wordt van uitwisselingsdebieten verband houdend met dichtheidsgelaagdheid of getijvariatie. Slechts zijdelings wordt ingegaan op wateruitwisseling door halingen in het systeem havenbekken-rivier en door variatie over de diepte van de stroming in de havenmond. Wel wordt aan de invloed van wateronttrekking of lozing in het havenbekken op uitwisselingsdebiet en op het stromingspatroon in de haven aandacht besteed. Het doel van het onderzoek is informatie te verkrijgen over de uitwisseling van slib door de havenmond. Hiervoor is kennis van de uitwisselingsdebieten door de havenmond, van de concentratieverschillen aan slib tussen binnenkomend en uittredend water en daarmee van de verblijftijden van het water in verschillende gedeelten van de haven onontbeerlijk. Tevens is het de bedoeling na te gaan in hoeverre een betrouwbaar1-dimensionaal transportmodel voor het slib in de haven mogelijk is en wat de te gebruiken coefficienten in dat geval zijn. Eventueel kan het onderzoek leiden tot suggesties voor een beter toepasbaar model. Ook kunnen de gevonden stromingspatronen dienen als controle voor berekeningen met 2DH-rekenmodellen zoals WAQUA.Hydraulic EngineeringCivil Engineering and Geoscience
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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