1,720,968 research outputs found
Additive Manufacturing of Wood-Based Polymer Composites Fabricated Using Vat Photopolymerization for Design Applications
Full text linkIn the present research work, wood-based composites were prepared by adding different poplar powders within a soybean-oil-based resin choosing liquid crystal display (LCD) as vat photopolymerization (VP) among the additive manufacturing (AM) technologies useful for polymer processing. The aim was to combine the advantages of AM with the valorisation of poplar wood powder wastes from the plywood industry to obtain innovative and more sustainable composite materials as alternatives to the classical fossil-based materials, for interior design applications. Several photocurable formulations were prepared using an acrylate epoxidized soybean oil (AESO) resin as polymer matrix and isobornyl methacrylate (IBOMA) as reactive diluent, in the presence of 2 wt.% of phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) as photoinitiator. Bio-based composites were obtained by adding to the AESO formulations 3 wt.% of different wood poplar powders (PI and PIV), two by-products coming from plywood panel production, and by 3D printing different parts in an LCD 3D printer. A comprehensive characterization of the composites fabricated via VP was carried out. Rheological, thermal, morphological, and mechanical measurements were done to investigate the final properties of the 3D printed wood-based composites. Several 3D printed components were fabricated showing different level of detail and complexity. The specimens showed enhanced final properties, in terms of elastic modulus, glass transition temperature, and storage modulus, due to the reinforcing effect induced t the presence of the fillers.
This research demonstrates that bio-based components can be successfully 3D printed via LCD, including objects with potential application in interior design, such as joints and connections, highlighting the material’s suitability to realize customized and more sustainable elements for design-oriented applications
Review: bio‐based photopolymers for additive manufacturing
No full textThis review aims to provide a comprehensive overview of photopolymers for additive manufacturing (AM) applications, with particular attention to the 3D printing (3DP) processes for thermosetting polymeric materials and the main mechanisms and reactions involved during their photopolymerization process. The introduction highlights the principles and significance of photopolymeriza-tion in AM. It is followed by an exploration of free-radical (FRP) and cationic photopolymerization (CP), the two main mechanisms underpinning these pro-cesses. The focus then shifts to the AM technologies suitable for photopolymer processing. Photopolymer-based AM technologies, such as vat photopolymerization (VPP) and ink-jet (IJ) photopolymerization, are examined in detail. VPP has been widely studied for its ability to produce 3D-printed components with highly complex geometries and good final resolution by selectively curing liquid resin in a vat through targeted light-activated polymerization reactions. Similarly, IJ, which involves depositing droplets of photocurable resins in a controlled man-ner and curing them with light, offers precise material deposition, enabling the creation of more detailed and intricate structures. Finally, the review addresses the shift from monomers derived from fossil-based sources to those coming from bio-sources. This transition is driven by the harmful effects of using polymers derived from non-renewable resources and the increasing emphasis on sustain-able development. Research and development efforts aimed to use bio-based precursors are discussed in this context. The conclusions and outlook summarize the findings and offer perspectives on future research directions in photopolym-erization for AM, emphasizing innovations in bio-based precursors and advancements in AM technologies
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
- …
