1,720,958 research outputs found
Energy analysis of using macroalgae from eutrophic waters as a bioethanol feedstock
No full textEutrophication is an environmental problem in a majority of shallow water basins all over the world. The undesired macroalgae has been proposed as a biomass resource for bioethanol production and we have analysed the environmental sustainability of two case studies: Orbetello Lagoon (OL), Italy, and Koge Bay (KB), Denmark. Today, macroalgae are collected and stored in landfills to provide a solution for the excess production. An emergy assessment revealed that the main environmental support for macroalgae growth relates to water in both case studies. In OL, rain represents 51% of the emergy use, and in KB runoff from agricultural land constitutes 86%. The environmental support needed for producing one Joule of bioethanol is somewhat more than for a number of other bioethanol feedstocks being 2.12 x 106 solar equivalent Joules (seJ) for OL and 2.56 x 106 seJ for KB. However, a high percentage of the environmental support comes from local renewable flows being 40% for OL and 88% for KB. The difference between the two case studies is partly due to the contribution of energy from waves, which plays an important role in carrying macroalgae towards the coast in Koge Bay. Energy-wise, one J of fossil energy is required directly or indirectly to produce 0.09J of bioethanol for OL or 0.44J of bioethanol for KB, i.e. the energy return on (energy) invested (EROI) is less than 1. An alternative scenario was developed in order to investigate improvements of system efficiency. This was analysed with the full-requirement approach as well as with a marginal-requirement approach accounting only what the bioethanol production requires of additional processes, i.e. mainly transportation and conversion of the macroalgae in a biorefinery facility which is assumed to be situated close to an existing industry producing waste heat. Both emergy and EROI analyses showed that only a relatively small amount of resources has to be added to the existing system to produce the bioethanol, e.g. the EROI increased to above 1 in both systems. With the marginal approach, macroalgae may be appreciated as a resource for bioethanol production instead of considered as an environmental problem. (C) 2014 Elsevier B.V. All rights reserved
Comparative life cycle assessment of biowaste to resource management systems – A Danish case study
No full textWaste to Energy combustion plants currently process most of the organic fraction of the household waste. This study presents an assessment of the environmental performance of an increased circular bioresource management system obtained by reallocating the organic fraction of the household waste from combustion (Reference Scenario) to biogas and fertilizer production (Alternative Scenario). The goals defined in the Danish National resource action plan for waste management, i.e. 33% reduction of organic fraction household waste dry weight, is taken as a case study. A comparative life cycle assessment of the diverting of the organic fraction of the household waste away from a Waste to Energy combustion plant towards sludge-and manure-based biogas plants in North Zealand (Denmark) shows a net increase in renewable electricity production of 39% at the expense of a reduction in heat production of 8%. Moving up the waste hierarchy results in a net greenhouse gas emission reduction of 100 kg CO(2)eq. per ton of dry weight biowaste treated, corresponding to a 10% of reduction in CO2 emission. The latter accompanied by a net reduction in depletion of fossil resources of 11% and a reduction in the impacts on Freshwater and Marine Eutrophication of 4.8 t P eq. and 3.6 t N eq., respectively. As such, the modelled increased circular bioresource management indicates significant improvement of the efficiency in use of resources in biowaste. However, trade-offs occur due to the presence of micropollutants in the natural fertilizers that results in future increased damage cost on terrestrial ecosystems and human health exists. (C) 2016 Elsevier Ltd. All rights reserved
Environmental-economic analysis of integrated organic waste and wastewater management systems: A case study from Aarhus City (Denmark)
Full text linkThis study presents a comparative analysis of the environmental and economic performances of four integrated waste and wastewater management scenarios in the city of Aarhus in Denmark. The purpose of this analysis is to deliver decision support regarding whether (i) the installation of food waste disposers in private homes (AS1) or (ii) separate collection and transport of organic waste to biogas plants is a more viable environmental and economic solution (AS2). Higher environmental benefits, e.g., mitigation of human health impacts and climate change, are obtained by transforming the existing waste combustion system into scenario (ii). Trade-offs in terms of increased marine eutrophication and terrestrial ecotoxicity result from moving up the waste hierarchy; i.e., from waste incineration to biogas production at wastewater treatment plants with anaerobic sludge digestion. Scenario (i) performs with lower energy efficiency compared to scenario (ii). Furthermore, when considering the uncertainty in the extra damage cost to the sewer system that may be associated to the installation of food waste disposers, scenario (ii) is the most flexible, robust, and less risky economic solution. From an economic, environmental, and resource efficiency point of view, separate collection and transport of biowaste to biogas plants is the most sustainable solution
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
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