1,720,967 research outputs found
Environmentally Degradable Plastics: Thermal Behavior of Polymer Blends Based on Waste Gelatin
No full textComposite Films Based on Waste Gelatin. Thermal-Mechanical Properties and Biodegradation
No full textSwelling capacity of sugarcane bagasse-g-poly(acrylamide)/attapulgite superabsorbent composites and their application as slow release fertilizer
No full textIn this work, sugarcane bagasse (SCB)-g-poly(acrylamide)/attapulgite superabsorbent composites (SBCs) were prepared by graft copolymerization of acrylamide (AM) onto SCBin presence of attapulgite (ATP) using N,N′-methylene-bis-acrylamide (MBA) as crosslinker and potassium persulfate (KPS) as initiator in aqueous solution. The composite structures were characterized by Fourier Transform Infrared spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). The effect of the initiator, crosslinker amounts and attapulgite/hydrogel weight ratio (0.0–14.4 wt%) on the swelling capacity was investigated. The results indicated that highest swelling capacity in distilled water was 920 g/g, obtained with the composite containing 1.3 wt% KPS, 0.08 wt% MBA, 79.9 wt% AM, 5.3 wt% ATP and 13.3 wt% SCB. Different SCBs were loaded with urea and its release was evaluated over time, showing that the urea release rate decreased by increasing ATP amount up to14.4 wt%. Therefore, the SCB-g-poly(AM)/ATP composites could have promising applications also as controlled urea release fertilizer
Environmentally sound blends and composites based on water soluble polymer matrices
No full textThe realization of plastic items intended to not constitute an environmental burden once they become waste or simply post-consume products represents the main goal of a research project focused on the utilization of water-soluble synthetic polymer, e.g. poly(vinyl alcohol), and natural raw materials for the preparation of cast films and composites. A series of plastic sheets and films were obtained from water solution and dispersion of poly(vinyl alcohol) and waste gelatin, as well as from blends of the vinyl polymer with lignocellulosic materials such as sugar cane bagasse. Thermal properties of the films, as well as their biodegradation behavior under different incubation conditions, and in particular under soil burial conditions, were investigated with the aim of identifying the compositions best suited to obtain films and composites suitable for agricultural applications
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
Composited Materials based on Gelatin and Fillers From Renewable Resources: Thermal and mechanical Properties
No full textVariations 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
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