1,720,958 research outputs found
Isosorbide dioctoate as a "green" plasticizer for poly(lactic acid)
No full textIsosorbide dioctoate (SDO), a "green" plasticizer for poly(lactic acid) (PLA), was synthesized and evaluated as bio-based alternative to traditional phthalate plasticizers. The structure of SDO was confirmed by FTIR and H-1 NMR. The miscibility, thermal properties, mechanical properties and transparency of the PLA/SDO blends were investigated in detail, and PLA plasticized with commercial dioctyl terephthalate (DOTP) was used for comparison. The calculated solubility parameter and SEM morphological analysis indicated that SDO exhibited better miscibility with PLA than that of DOTP. Results from DSC showed that SDO was more effective than DOTP in lowering the glass transition temperature of PLA. Moreover, the elongation at break of PLA/SDO blends was significantly improved with the increasing of SDO content. The effect of the concentration of SDO on transparency of PLA blends was negligible, while PLA plasticized with 20 wt.% DOTP exhibited poor transparency. In conclusion, SDO showed attractive potential as alternative to phthalate plasticizers. (C) 2015 Elsevier Ltd. All rights reserved
Preparation and characterization of thermoplastic starches and their blends with poly(lactic acid)
No full textTwo different thermoplastic starches (TPS), namely maleic anhydride grafted starch (MA-g-starch) and epoxidized cardanol grafted starch (Epicard-g-starch), were successfully prepared by chemical modification without the addition of any plasticizer. The structure and properties were characterized by nuclear magnetic resonance (NMR), X-ray diffraction (XRD), hot press testing, scanning electron microscopy (SEM) and contact angle meter, respectively. Results from XRD showed that the highly crystalline structure of native starch was destroyed after modification. Continuous phase was obtained from both of the chemically modified starches after hot pressing at 130 degrees C, indicating that they have good thermoplasticity. Subsequently, they were melt-blended with PLA. It was found that the Epicard-g-starch had a much finer dispersed phase size than MA-g-starch in PLA matrix due to its better hydrophobicity. As a result, the mechanical properties of PLA/Epicard-g-starch blend were superior to those of PLA/MA-g-starch blend. (C) 2015 Elsevier B.V. All rights reserved
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
Surface hydrophobic modification of starch with bio-based epoxy resins to fabricate high-performance polylactide composite materials
No full textThe surface hydrophobic modification of starch was firstly made by use of two bio-based epoxy resins to fabricate the fully bio-based polylactide (PLA)/starch composites with superior mechanical and thermal properties. As demonstrated by FT-IR and H-1 NMR, the surface of starch was successfully modified with the epoxidized itaconic acid (EIA) or epoxidized cardanol (Epicard) to produce hydrophobicity with the contact angle increasing from 44 degrees to similar to 100 degrees. After modification, the interfacial adhesion between starch and PLA was obviously improved, which can be clearly observed by SEM. As a result, an obvious increase of tensile strength from about 35 MPa to over 50 MPa was obtained. Moreover, with the strong interaction formed at the interface between modified starch and PLA, the crystallization ability of PLA was also enhanced as confirmed by DSC and DMA. This study suggested us a simple but effective surface modification technique by utilizing the bio-based epoxidized modifiers to improve interfacial adhesion in fabricating fully bio-based PLA/starch composites with superior properties. (C) 2014 Elsevier Ltd. All rights reserved
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