1,720,958 research outputs found
Design of Crashworthy Automotive Composite Structures
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Controlled microalgae culture as a reactive nitrogen filter: from ideation to prototyping
Get PDFFreshwater pollution caused by excessive reactive nitrogen in water due to extensive use of nitrogen-based fertilizers poses an ecological threat. As a result of an innovation management program, the problem is explored through the stages of research, ideation, solution (identification and validation), and prototyping/execution. After a description of the problem and a theoretical argumentation of the methodology used to approach it, each of these stages is discussed and the solution is presented. A water treatment module that grows microalgae for water purification and nitrogen recovery is proposed. Algae grown can be used as biomass material for animal nutrition, biofertilizers, and for the cosmetics industry
An innovative fixture for testing the crashworthiness of composite materials
Get PDFDespite the growing diffusion of composite materials in automotive and aerospace sectors, a standard procedure for testing their crashworthiness has not been developed yet. At present, the international standards for testing composite materials under impact conditions are not adequate to test their crush behavior.
In this paper, a procedure for measuring the energy absorption due to the compressive crushing of a composite flat specimen, along its mid plane, is proposed. The experimental setup requires a fixture to hold the specimen and to avoid its buckling and an instrumented drop weight tower to obtain the force-displacement curves with the aim of calculating the Specific Energy Absorption.
The paper will describe the adopted test procedure and some of the features of the newly developed experimental setup. The effectiveness of the procedure is demonstrated by testing several glass fiber-epoxy specimens under different impact energies
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
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
Newly Developed Anti-Buckling Fixture to Assess the In-Plane Crashworthiness of Flat Composite Specimens
Get PDFDespite superior specific mechanical characteristics of carbon-fiber-reinforced polymers (CFRPs), a lack of understanding of their fracture mechanisms under different impact conditions has limited the application of CFRP energy-absorbing structures. To avoid complex and expensive tests on the final structure, it is more convenient to test flat elements. To prevent catastrophic crushing due to the global buckling, flat specimens must be supported by a specific fixture. Previously developed fixtures had shortcomings like tearing of the specimen, jamming of the fixture, short crushable length, or they were specifically designed only for one failure mode. This newly designed fixture overcomes the limitations of previously published solutions. The final configuration includes cylindrical anti-buckling columns 10mmin diameter and spaced 65mmapart with adjustable heights. The fixture is designed for rectangular specimens with dimensions of 150 x 100 mm and different thicknesses up to 16 mm, like the ones mandated by the ASTM D7137 standard test method for compression after impact analysis. Other features of this new fixture are the possibility to study the effects of different defects on the crashworthiness of composites, higher crushing area, and integration with Instron drop tower and hydraulic testing machines
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