1,721,012 research outputs found
Photocurable resin/microcrystalline cellulose composites for wood protection: Physical-mechanical characterization
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Mechanical properties and strain monitoring of glass-epoxy composites with graphene-coated fibers
Full text linkAn engineered interphase can improve the mechanical properties of epoxy/glass composites simultaneously inducing a piezoresistive response. To prove this concept, E-glass fibers were coated with graphene oxide (GO) by electrophoretic deposition, while reduced graphene oxide (rGO) coated fibers were obtained by subsequent chemical reduction. The fiber-matrix interfacial shear strength (measured by the single-fiber fragmentation test) increased for both GO and rGO coated fibers. Unidirectional composites with a high content of both uncoated and coated fibers were produced and mechanically tested under various configurations (three-point bending, short beam shear and mode-I fracture toughness, creep). Composites with coated fibers performed similarly or better than composites prepared with uncoated fibers. Finally, composites with rGO coated fibers were tested for their piezoresistive response under both static and dynamic conditions. The electrical resistance changed proportionally to applied strain thus confirming the possibility of using composites with rGO coated fibers as strain sensors in load-bearing components
Enhancement of interfacial adhesion in glass fiber/epoxy composites by electrophoretic deposition of graphene oxide on glass fibers
Full text linkNMP is supported by the European Research Council (ERC StG Ideas 2011 BIHSNAM no. 279985 on “Bio-Inspired Hierarchical Super Nanomaterials”, ERC PoC 2015 SILKENE no. 693670 on “Bionic silk with graphene or other nanomaterials spun by silkworms”, ERC PoC 2013-II KNOTOUGH no. 632277 on “Super-tough knotted fibres”), by the European Commission under the Graphene Flagship (WP10 “Nanocomposites”, no. 604391) and by the Provincia Autonoma di Trento (“Graphene nanocomposites”, no. S116/2012–242637 and reg. delib. no. 2266)
Photocurable resin/nanocellulose composite coatings for wood protection
Full text linkNovel UV-light curable methacrylic-siloxane-cellulose composite coatings for wood protection were prepared, fully characterized and, then, applied on walnut wood samples in order to assess the potential protective performances of the wooden treated substrates, such as hydrophobicity and surface properties. A comparison between nanocellulose and microcellulose filled coatings (5 and 10 wt%) was also performed. Thermal-mechanical analysis highlighted the higher effectiveness of nanocellulose in increasing the glass transition temperature, improving thermal and dimensional stability and stiffness of the neat photoresin with respect to microcellulose. A more pronounced increase of hydrophobicity (contact angle and water capillarity), surface hardness (Shore D and pencil scratch tests) of the neat UV-light cured matrix filled with nanocellulose and applied on wood was, finally, observed in comparison to microcellulose composites
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
Strengthening of polypropylene–glass fiber interface by direct metallocenic polymerization of propylene onto the fibers
Full text linkThis work deals with the development of a new approach to improve the interfacial adhesion and properties of polypropylene–glass fiber composites. The chemical anchoring of the matrix polymer on glass fibers was improved by direct metallocenic polymerization of propylene onto the fibers surface. The experimental route involves an initial contact with methylaluminoxane (MAO) and hydroxy-a-olefin to generate the anchorage points on the fiber surface, followed by a propylene polymerization catalyzed by EtInd2ZrCl2 (metallocene)/MAO. During the polymerization reaction, polypropylene chains grow on the glass fiber surface. This reaction was studied for different hydroxy-a-olefin concentrations and its effectiveness was characterized by scanning electron microscopy (SEM) with X-ray disperse energy microanalysis. An evaluation of the fiber–matrix interfacial shear strength (ISS) was performed by single-fiber fragmentation tests on model composites. Depending on the hydroxy-a-olefin concentration, the surface treatment induced an increase of the ISS with respect of the untreated fibers by a factor ranging from 1.7 up to 2.1. The improved interfacial adhesion level was also confirmed by SEM observations of the morphology of the fiber–matrix region of cryogenic-fractured surfaces of composites.Fil: Etcheverry, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ferreira, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Capiati, Numa Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Pegoretti, Alessandro. University of Trento; ItaliaFil: Barbosa, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin
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