1,720,972 research outputs found
Life cycle assessment of emerging environmental technologies in the early stage of development: A case study on nanostructured materials
Full text linkThe use of nanostructured materials has been recently proposed in the field of environmental nanoremediation. This approach consists in using nanomaterials not directly, but as building blocks for the design of nano-porous micro-dimensional systems, overcoming the eco- and health-toxicology risks generally associated with the use of nano-sized technologies. Herein we report the use of life cycle assessment (LCA) as an eco-design tool for optimizing the production of cellulose nanosponges (CNS), nanostructured materials recently developed for water remediation purposes. LCA was applied from the acquisition of raw materials to the synthesis of CNS (from cradle-to-gate), considering three production systems, from the lab-level to a modeled scale-up system. The lab-scale LCA identified the main environmental hotspots, namely the energy-consuming steps and the final purification of the material (washing step). In a second lab-scale production, an improvement action could be implemented, switching the washing solvent from methanol to water and decreasing the washing temperature. A second LCA showed a reduced contribution to the impacts from the materials, while the global impacts remained within the same order of magnitude. A simulated scale-up of the process allowed to optimize the energy-consuming steps and the water consumption, through internal recycling. A third LCA assessed the resulting benefits and a decrease in the global impacts by two orders of magnitude. Our study contributes to the discussion of LCA community, providing a focus on the importance of scaling-up of emerging technologies, namely nanostructured porous materials, highlighting the benefits of a LCA based approach since the very beginning of product design (eco-design)
Life cycle thinking in sustainable supply chains: The case of rubberized asphalt pavement
No full textEnd of life tires require sound accounting of environmental performances to design sustainable procedures for material recovery. Their use in rubber modified asphalt provides could lead to the improvement of technical and environmental performances of asphalt roads, but the effectiveness of simplified procedures is to be proved. During LIFE+ project ROADTIRE, a rubber modified asphalt road prototype, with the upper surface layer containing 10% crumb rubber in the bituminous binder, was implemented in Lamia, Greece. The prototype was compared to a conventional asphalt road by Life Cycle Assessment to evaluate the environmental performances and the results were critically interpreted to highlight its benefits. The impact categories considered, assessed with the ReCiPe Midpoint (H) v1.06/Europe ReCiPe H method, were: Climate change, Ozone depletion, Human toxicity, Photochemical oxidant formation, Terrestrial acidification, Freshwater eutrophication, Freshwater ecotoxicity, Terrestrial ecotoxicity, Water depletion, Fossil depletion. Compared to the conventional asphalt road, the global environmental performances of the rubberized asphalt road are improved of 30-40%, depending on the impact category. For both scenarios, the road construction phase, with bitumen production, is the most impacting process, compared to maintenance and end-of-life. The global environmental advantages are proved to depend on the longer lifetime and the less maintenance required for the rubberized asphalt road, as indicated from laboratory tests. It is therefore important to monitor such parameters during the road lifecycle in order to validate this preliminary outcome. Based on these results, policy and management implications are discussed. © 2015, Gh. Asachi Technical University of Iasi. All rights reserved
Difunctionalized en-capped macromers of N-vinyl-2-pyrrolidinone as precursors of ampliphilic block copolymers
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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
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