1,720,954 research outputs found
Porcelain stoneware with pegmatite and nepheline syenite solid solutions: Pore size distribution and descriptive microstructure
No full textInvestigations correlating the pore size distribution-cumulative pore volume to the microstructure are used to compare the efficiency of two solid solutions of pegmatite and nepheline syenite as fluxing agents for the design of porcelainized stoneware. Particularly the fusibility of the two solid solutions was modified by adjusting the CaO content of the bodies. As results, the pegmatite based flux produced an extended viscous phase capable on embedding the crystalline phases and close open porosity as from 1175°C. Conversely, the bodies with nepheline syenite remained relatively porous up to 1225°C although the similar results of the mechanical strength at this temperature. The investigations on microstructure, pores size distribution and cumulative pore volume indicated almost complete reduction of the open pores in the pegmatite based bodies and the development of a band of closed pores ranged between 0.080 and 0.9μm showing P series as a more compact structure. For the nepheline syenite based bodies, the incomplete reduction of the open pores and the relative absence of the band of pores between 0.080 and 0.9μm were ascribed to the difference in fusibility and the viscosity of the glassy phases. These differences were interpreted in term of the differential action of CaO in Na2O-Al2O3-SiO2 and K2O-Al2O3-SiO2 on the amount and viscosity of the liquid phase formed already described in the literature. © 2013 Elsevier Ltd
Sintering behaviors of two porcelainized stoneware compositions using pegmatite and nepheline syenite minerals
No full textSemi-vitreous bodies, with flexural strength of ~78 MPa and water absorption of ~0.4 % for the optimal maturated specimens, were successfully prepared with solid solutions of pegmatite and nepheline syenite, respectively, for the full dense (P) and relatively porous composition (G). Despite the similarity on the bulk chemical composition of the two formulations, it was found that their thermal behaviors were significantly affected by the action of CaO on the flux system considered leading to earlier vitrification of P specimens with high flexural strength as from 1,175 C. Conversely, the flexural strength of G specimens increases progressively with soaking time and temperature development up to 1,225 C. The positive action of 5 mass% of CaO in the vitrification range of pegmatite solution, the relative low temperature of maturation of the semi-vitreous matrices, and the results of water absorption allow us to describe the formulations studied to offer promising potential in the production of sustainable and low-cost porcelainized stoneware. The high strength of P at relatively low temperature could be explained by the matrix-strengthening theory, while the extent of crystallization of G could be ascribed to the mullite theory. © 2013 Akadémiai Kiadó, Budapest, Hungary
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
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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