1,721,525 research outputs found
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
Design and fabrication of customized tracheal stents by additive manufacturing
No full textAdditive Manufacturing (AM) is already becoming part of our life from a technological, economic and social point of view. Nowadays, it is applied in several manufacturing sectors. In particular, AM shows huge opportunities in the medical field and for healthcare applications. Due to its capability to produce complex geometries directly working on medical 3D images and thanks to the possibility to 3D-print biocompatible materials, AM is a key technology for the fabrication both of external and internal medical devices. In particular, the use of AM for medical applications is typically articulated in three steps: 3D-scanning of the patient anatomy, segmentation the medical scan and elaboration through CAD software for the preparation of a STL file suitable for the AM process. One of the main research topic in this field is the definition and optimization of procedures that, taking precise data from an individual patient, could be applied to the design and fabrication of customized components for medical applications. Therefore, this paper presents a project aimed at the fabrication of customized tracheal stents starting from the actual patient anatomy. In particular, it follows an approach based on molds FDM fabrication followed by biocompatible silicone casting. Molds were designed to obtain a tracheal stent based the patient anatomical tracheal lumen and were fabricated using FDM technology. Moreover, since the surface roughness is one of the most critical aspects related to the FDM, the produced molds were finished with a chemical surface post-treatment based on the use of acetone vapours. Overall, the whole developed procedure results in an effective custom-made medical devices realization
Characterization of the Chemical Finishing Process with a Cold Acetone Bath of ABS Parts Fabricated by FFF
No full textAdditive Manufacturing (AM) is going through an impressive growth from 15 years to today. Its main strength is the capability to fabricate complex parts for a wide range of applications. In contrast, its typical layer-by-layer building method can cause a low surface finishing of the parts. Post-processes as chemical treatments can be used to enhance the finishing but few studies are published on the topic. This work focuses on the surface prost-treating of ABS parts made by FFF. During the treatment, the part is immersed in a cold acetone bath to chemically dissolve and smooth its surface. The process is characterized by varying the duration of treatment, the orientation of the surface with respect to gravity and using samples covering the full range of initial roughness. The results are statistically analyzed showing the robustness of the process. Moreover, the effectiveness of the treatment is proven by an overall reduction of the roughness which is 97% on average within 1 min of treatment
Process parameters influence on friction coefficient in sheet forming operations
No full textIn conventional sheet forming processes, such as stamping or drawing, significant contact phenomena take place between workpiece and die surfaces. Especially, relative motion and normal loads generate friction which influences some aspects of processes such as material flow, tools wear and life and total force needed to complete the process. In the current paper an experimental test campaign has been carried out using a large scale pin-on-disk device designed and realized by the Authors to investigate the influence of pressure, sliding velocity and temperature. The purpose is to test the developed device and to find which and how these parameters mostly affect friction. The pin-on-disk test consists of two specimens, a pin and a plate representing respectively die and workpiece, which are compressed by means of a known force and then moved one over the other. Compression and friction forces are sampled during the tests and the friction coefficient is estimated as the ratio of these two forces. The tested materials are H13 die steel on FeP04 and AZ31 sheets
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