1,720,958 research outputs found
Measurement of agglomerate strength distributions in agglomerated powders
No full textA new technique for measuring the strength distributions of powder agglomerates was developed. It involves the use of a calibrated ultrasonic sound field. The strength distributions of hollow glass microspheres were determined independently by mercury porosimetry, and then used to calibrate the sound field; breaking pressures from 1 to 76 MPa could be obtained by varying the energy input to the ultrasonic transducer;Agglomerate strength distributions were measured for a variety of yttria and yttria-stabilized zirconia powders, which were prepared by solution precipitation methods. Different preparation methods were used in order to obtain powders containing agglomerates with different characteristics. Special yttria powders containing agglomerates of 0.1 [mu] m, spherical, monosize spheres were also prepared. BET surface area, tap density, pressed density, compaction curves, and mercury intrusion curves were also obtained. The powders were pressed and sintered, and the sintered density measured for each pellet;Smooth curves could be drawn when agglomerate strength was plotted against sintered density; the sintered density of the powders also could be ranked directly according to the strength of the agglomerates in each powder. This is the first time that quantitative correlation between agglomerate strength and sintered density has been shown experimentally;Except for the model yttria powders containing monosize spherical particles, there was no correlation between sintered density and any other measured powder parameter. For this model powder, most of measured powder parameters correlated directly with sintered density, in almost textbook fashion. It was also possible, using these model powders, to isolate the effect of agglomerate strength on sintered density by holding all other powder characteristics constant. This is the first time that the effect of agglomerate strength alone has been shown for a real powder. ftn * DOE Report IS-T-1325. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy.</p
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
Modification of Surface Charge Characteristics for Unsupported Nanostructured Titania-Zirconia UF/NF Membrane Top Layers With Calcination Temperature
No full textErdem, Ilker/0000-0001-5743-0835;Ceramic membranes are more advantageous alternatives especially for harsh working conditions when compared with the polymeric membranes. The porous multilayer structure of the ceramic membranes (composed of support, intermediate, and top layers) can be prepared via different oxides. Titania and zirconia, having superior properties, are mainly preferred for the top layer formation. The separation properties of the membrane are both dependent on pore morphology and surface charge of the oxide(s) forming the top layer. The effect of surface charge in separation may be very significant in case of filtration of charged species with relatively lower mass as in the ultrafiltration (UF) and nanofiltration (NF). In this study, unsupported membrane top layers were prepared with varying titania/zirconia ratios by sol-gel technique. Their surface charges at different pH conditions after calcination at varying temperatures (400 degrees, 500 degrees, and 600 degrees C) were determined. The surface charge of the pure titania (full Ti) top layer was decreasing with the increasing calcination temperature. The highest magnitudes of zeta potential for both acidic and basic conditions were measured via Zr rich top layer (TiZr2575) at calcination temperatures >= 500 degrees C, which was composed of anatase, rutile (titania), and tetragonal (zirconia) phases after calcination. The tailor-made top layer can be prepared with modifications during membrane preparation
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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