1,721,011 research outputs found
Reinforcing Potential of Mineral-Impregnated PBO Fibre Yarns in a Sustainable Blended Matrix
No full textTextile Reinforced Concrete (TRC) is now a key technology for the structural rehabilitation of deteriorated concrete structures, as well as for novel, versatile and highly customisable thin structures with optimised raw material utilisation. In order to fully exploit the excellent strength and modulus of high-performance fibres, like PBO, a uniform impregnation of the yarns is generally applied to achieve optimum stress transfer from the inorganic matrix to the load-bearing reinforcements. Mineral impregnation techniques for high-tenacity multifilament textiles are gaining increasing popularity over their polymeric counterparts mainly due to their enhanced thermal stability and good potential for reducing environmental impact. This paper presents and discusses the pull-out behaviour of PBO yarns embedded in a newly developed limestone calcined clay cement (LC3) mortar. Emphasis is placed on the bond properties of two grades of PBO fibres through pull-out tests. It is shown that the mineral impregnation plays a crucial role, not only in improving the mechanical response in terms of bond, but also in overcoming the differences in stiffness and properties of the PBO fibres, allowing the use lower grade fibres without compromising the overall performance of the composite
Investigating the Potential of Limestone and Calcined Clay as a Substitute for Fly Ash in Strain-Hardening Cementitious Composites (SHCC)
No full textThis study focuses on the feasibility of replacing fly ash with limestone and calcined clay in strain-hardening cementitious composites (SHCC). Three types of composites were considered: a reference one containing fly ash and the other containing two distinct calcined clays (moderate and high metakaolin content) as supplementary cementitious materials (SCM). Mixtures utilized portland cement (PC) with clinker factors of 0.4 and 0.3, reinforced with 2 vol.% high-density polyethylene (HDPE) fibers. At first, the R3 bound water test was carried out to explicitly assess the reactivity of fly ash and the two calcined clays. Subsequently, the compressive and direct tensile behavior of the SHCCs after 28 days of curing age was evaluated. The results revealed that the SHCCs incorporating calcined clays outperformed their counterpart in terms of compressive strength, tensile strength, and ultimate strain, owing to their high pozzolanic activities, and physical properties, particularly their distinct morphologies. Crack analysis conducted through digital image correlation (DIC) highlighted that the SHCCs with calcined clays established a stronger fiber/matrix interface. In conclusion, this research provides valuable insights into the design of ductile SHCC with novel limestone calcined clay cement (LC3), for enhanced sustainability and cost-effectiveness
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
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
Hierarchical CNT-Coated Basalt Fiber Yarns as Smart and Ultrasensitive Reinforcements of Cementitious Matrices for Crack Detection and Structural Health Monitoring
No full textBasalt fiber (BF) yarns were homogeneously coated with single-walled carbon nanotubes (SWCNT) following a versatile and scalable roll coating wet deposition process. The SWCNT layers turned the intrinsically electrical insulating BFs into highly conductive reinforcements, which were deployed as smart and ultrasensitive sensors for the crack detection of cementitious matrices. A subsequent thermal drying process achieved a uniform and dense SWCNT coating confirmed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The BF-SWCNT yarns introduced in a cementitious matrix exhibited a significant variation of their fractional resistance change (∆R/R0) upon being exposed to in-situ three-point bending experiments. This response renders the BF-SWCNT as novel strain sensors for cement-based elements possessing high sensitivity factor for crack detection. A subsequent analysis of the fractured surfaces via SEM imaging revealed a good interaction between the reinforcements and the cementitious matrices with adhesive failure mechanisms occurring during the fracture process. The developed BF-SWCNT sensors as model composites of single yarns in a cementitious matrix promisingly envisage the use of CNT-coated BFs for sensing applications in cementitious large-scale composite structural parts or strengthening layers for existing structures
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