1,721,407 research outputs found
Modeling the filament of magnesium alloys
Full text linkThe realization of the required geometry when representing the complex part of an object is determined by discretization of the material amount to be applied by a filament. The FDM of metals could in this way be competitive with conventional technologies to net shape making. The possibility to realize smaller and smaller filaments whose characteristics can be given in the extruding tool-material system by using proper geometries and parameters in order to produce the temperature rise inside the container is investigated. The analytical modeling proposed describes the extrusion behaviour of two magnesium alloys, that are the AZ31 and the ZM21 ones. That to perform a filament section of 0.4-0.5 mm in radius, beginning by a one of about 1.5 mm, with which to apply metal ribs. The effect of friction, distortion and heating phenomena as well as the solid fraction are considered on the stress vs. displacement curves inside the extruder until submillimeter diameter. The material model updated to consider the higher strain rates evidences the different behaviour of the models in describing different strain rates conditions useful to realize the filament geometry
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
On the distribution of antibody affinities in the immune response. II. Application to experimental data of an analytical procedure to determine antibody distribution.
No full textOn the distribution of antibody affinities in the immune response. I. An analytical procedure to determine antibody distribution.
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Friction stir welding of AZ31 magnesium alloy thin sheets using “pin” and “pinless” tools
No full textThe present investigation aims at studying the friction stir welding of thin AZ31 magnesium alloy sheets (1.5 mm in thickness). Different tool geometries and process parameters were investigated. In particular, two properly designed tools, with different values of the shoulder diameter, have been used; each of them has been manufactured both with and without the pin (“pin” and “pinless” tool). It was shown that, as the tool characterised by the shoulder with lower diameter (8 mm) is used, the presence of the pin leads to the obtaining of peak stress and ductility values higher than those provided by the “pinless” tool. A strong beneficial effect on both ductility and strength of the joint is obtained by increasing the shoulder diameter (19 mm) even though the “pin” tool configuration is characterized by a very narrow welding window. An investigation has been also carried out in order to evaluate the micro-hardness distributions and the microstructure of the welded joints. A different metal flow can be clearly observed depending on the presence/absence of pin. Moreover, a more homogeneous microstructure is obtained using the “pinless” tool
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