1,720,963 research outputs found
Evaluation of mold roughness influence on injected thin micro-cavities
No full textDue to its ability to produce low-cost and high repeatable micro-polymeric parts, micro-injection molding is emerging as one of the most promising enabling technologies in many different fields. When approaching the micro-scale, different issues related to the process should be addressed, especially as the thickness of the cavities becomes very thin. In particular, the mold roughness affects the surface quality of the micro-components produced, like in macro-molding, but this could also encompass the complete filling of the parts. The main objective of the present paper is to evaluate the roughness influence of the mold on the non-Newtonian fluid flow during the micro-injection process in thin micro-cavities where the mold surface condition could affect the process due to the phenomena neglected in macro- or mesoscale as less important boundary conditions. The part design was properly conceived in order to neglect the effect of dimensions and geometry and to highlight the roughness contribution during the filling phase. The experimentation was performed using cavities with different roughness values and decreasing depths from 200 to 50 ?m, considerably lower than 250 ?m found in literature and manufactured by the micro-electrical discharge machining (?-EDM). The results of the experiments are discussed and show that cavity-surface roughness affects the process as the molding scale is decreased. In particular, in thin cavities, higher surface roughness promotes the filling of component
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
Preliminary study on surface influence on injection moulding process at micrometer scale
No full textInjection moulding of micro-featured plastic parts is becoming more and more important for applications of micro
system technologies in different fields (IT, healthcare, medicine) due to its capacity to produce low-cost and high
repeatable micro polymeric parts. However, approaching the micro world, different issues related to the process
should be addressed, especially as the depth of the mould cavity becomes very thin. In particular, the characteristics
of mould surface could affect not only the surface quality of micro components, but also the filling of injected parts.
This work aims to identify the effect of the superficial texture on the filling capability of thin cavity in micro
injection moulding process, and to evaluate the influence when the texture is obtained by different machining
processes. The results of the experiments, carried out using a polymeric material, are discussed in the paper and show
that, when the surface has an isotropic texture, the filling is proportional to the increase of the surface roughness,
whereas an oriented direction of the texture longitudinal to the flow front favours the injection process
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
Effect of cavity surface roughness and wettability on the filling flow in micro injection molding
No full textThe surface to volume ratio in micro injection molding is quite large and this makes interfacial phenomena particularly crucial for the effectiveness of the process. This criticality is more evident for thin parts molding, where the influence of roughness on the thermal boundary conditions is not negligible. In this case, the contact between polymer and mold significantly affects the heat transfer at the interface and consequently it strongly influences the polymer melt flow behavior. In this paper, the effects of the polymer-mold interface on polymer flow were experimentally investigated. In particular, the filling of a representative micro part with a thickness of 100 μm was studied in relation to surface roughness and mold wettability. The results showed that the state of the polymer-mold interface plays a fundamental role in the filling of thin-wall micro injection molding. In particular, the flow length increases with both the mold roughness and the contact angle between the molten polymers and the cavity surface
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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