1,720,955 research outputs found
Development of design criteria for novel 3D-printed quadric-surfaced sludge digesters for wastewater infrastructure
Get PDFThe quadric-surfaced sludge digester (QSD), also known as the egg-shaped sludge digester, has proven its advantages over traditional cylindrical digesters recently. A reduction in operational cost is the dominant factor. Its shell can be described as a revolution of a parabola with the apex and base being either tapered or spherical. This shape provides a surface free of discontinuities, which is advantageous regarding the efficiency during mixing. Since the shape does not produce areas of inactive fluid motion within the tank, sludge settlement and an eventual grit build-up are avoided. The stresses developed in the shell of the sludge digester, vary along the meridian and equatorial diameters. A non-dimensional parameter, ξ, defines the height-to-diameter aspect ratio which is used to delineate the parametric boundary conditions of the shell’s surface. Three groups of analyses were conducted to determine the orthogonal stresses in the shell of the QSD. The first-principles numerical models ran reasonably quickly, and many iterations were made during the study. The results showed that they were in within the range 5.34% to 7.2% to 2D FEA simulations. The 3D FEA simulations were within the range of 8.3% to 9.2% to the MATLAB time-history models. This is a good indicator that the first principles numerical models are an excellent time-saving method to predict the behaviour of the QSD under seismic excitation. Upon examining the criteria for the design, analysing the results for the 2D FEA simulations showed that the fill height is not a significant variable with sloshing however the 3D FEA showed that the hydrostatic pressure is a significant variable. With the maximum tensile stress of the 3D-printed ABS being 24.4 MPa, the overall maximum stress of 5.45 MPa, the material can be a viable option for the use of QSD construction in small island developing states (SIDS)
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
Numerical modelling of Quadric-Surfaced Sludge Digesters (QSD) within Wastewater Infrastructure using 3D Printing Techniques
No full textThe quadric-surfaced sludge digesters (QSDs), sometimes referred to as egg-shaped sludge reactors, are becoming more popular within wastewater treatment works as of recently. These tanked systems with their shell structure provide a surface free of discontinuities which is beneficial with regards to the efficiency during mixing and sludge settleability. QSDs do not produce areas of inactive fluid motion within the tank, sludge settlement and eventual grit buildup are prevented. The first principles models examined simulated Fused Deposition Modelling (FDM) or Fused Filament Fabrication (FFF), an additive manufacturing process for QSDs, under various loading parameters. A sludge digester of 25m in height and wall thickness of 500 mm (with materials of a 3-D printed polymer) was modelled and analysed with varying fill levels of 10%, 25%, 50%, 75% and 90% respectively. These simulated sludge fill levels were for both a fixed based and base isolated structure. The stresses developed in the shell of the sludge digester vary along the meridian and equatorial diameters. For this investigation two types of data were used, namely seismic maps of the Caribbean and electronic numerical time history acceleration records. The first principles numerical models included several iterations. The peak impulsive displacements varied between each model. The highest impulsive displacement occurred in the QSD with the lowest fill level (10% fill). This occurred for both the rigid base and isolated base models because of the smaller volumetric mass coupled with a lighter convective mass. By contrast, the lowest impulsive displacement occurred at 90% fill. The results of the study found that at a height of 3.1 metres from the base of the QSD, maximum peak displacement occurs. The base and at heights between 10 and 20 metres generated low displacements due to a rigidly fixed structure. The time-history analyses yielded favourable results when compared with the harmonic analyses. This is due to the transient decay of the frequency. The analyses did show an increase in the orthogonal stresses towards the apex of the QSD. On examining the results of the analyses, it was evident that internal stresses occurred in each orthogonal direction within the QSD
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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