1,721,016 research outputs found
Potential environmental benefits of direct electric heating powered by waste-to-energy processes as a replacement of solid-fuel combustion in semi-rural and remote areas
No full textThe combustion of wood-based biomass for domestic heating, which is common in rural and mountainous regions of Europe, entails significant local impacts on air quality. Worse conditions occur in low-income countries where the use of coal in household stoves is a common practice. The present paper aims at demonstrating that the combination of waste-to-energy (WtE) plants (based on direct or indirect waste combustion technologies) and direct electric heating (DEH) would be beneficial to reduce air pollution and, meanwhile, optimize the local waste management. Specifically, a WtE plant powering a DEH network will be compared with two reference scenarios of domestic heating: the use of wood/pellet stoves and coal stoves. The results show that shifting to a DEH system, powered by the nearby WtE plant, would reduce the emissions of total suspended particles, NOx, CO, VOCs, dioxins, PAHs and heavy metals by >99%, 27%, 97%, 96%, 93%, 94% and 32%, respectively, with respect to the use of solid fuel in household stoves. In addition, the higher degree of atmospheric dispersion of the off-gas from the stack of the WtE plant is expected to further reduce the impacts in terms of air quality, as estimated by an approach based on the concept of dilution factors. The avoided transportation of waste to other waste facilities outside the region would reduce the greenhouse gas emissions with respect to coal combustion and biomass burning, by 63% and 3%, respectively. The integration of local WtE and DEH could be also “mild”, opening to scenarios that could improve the local air quality without renouncing totally to the habits of domestic wood combustion in mountainous regions. Mild-DEH could be designed to integrate the domestic use of wood with electrical heaters, reducing fuel use and air pollution
PRIVATE ELECTRIC MOBILITY AND EXPECTED IMPACTS ON CLIMATE AND AIR QUALITY
Full text linkThe transition towards electric mobility is expected to reduce the direct emissions of local pollutants and greenhouse gases (GHGs) from road transport. However, the environmental sustainability of road traffic is also influenced by the level of sustainability of the sources that compose the grid mix used to charge electric vehicles. The present paper aims at understanding if electric mobility can improve air quality and reduce the emissions of global and local air pollutants even if this transition is not supported by a continuous increase in the share of renewable sources in the grid mix. To answer this research question, two scenarios were evaluated through the application of emission and dispersion modelling: (1) a present-case scenario characterized by the movement of vehicles whose composition matches the latest statistics on the Italian vehicle fleet and (2) a future-case scenario entirely composed of battery electric vehicles (BEVs). Both scenarios considered the same study area: a portion of an Italian urban area characterized by the presence of a canyon-like street. To take the comparison to extremes, the few BEVs in the present-case scenario were assumed as fed by renewable energy, while a nearby coal power plant was considered as the power source for the future-case BEVs. In spite of its deplorable energy source (coal) for BEVs, the future-case scenario would allow saving 12% GHG emissions with respect to the present-case scenario. The maximum annual mean concentrations of nitrogen oxides and total suspended particles in the future-case scenario were 99.9% and 68.0% lower in the street canyon compared to the present-case scenario. However, depending on the power plant considered, additional pollutants may be emitted, which may worsen the local air quality, especially if the location, the size and the characteristics of the emission source are not adequately evaluated
A Quali-Quantitative Comparison between In Situ and Ex Situ Waste-to-Energy Processes in Terms of Local and Global Impacts
Full text linkDespite the improvements made in recent decades on the emission control of waste combustion plants, the chronically low public acceptance still influences the strategical choices of local authorities, who may decide to export waste to other regions instead of treating waste locally in a waste-to-energy (WtE) plant. The present paper proposes a method to identify a more sustainable solution between local waste treatment and the export of waste. To do this, two waste-management scenarios were compared: (1) an in situ WtE scenario, considering a WtE plant in a region of about 500,000 inhabitants; and (2) an ex situ WtE scenario, considering the road transportation of waste to a WtE plant located in another region. This method yields an estimation of the maximum distance that trucks may cover to balance the emissions of the air pollutants released in the in situ WtE scenario. The methodology is based on the COPERT emission model and on emission factors of WtE processes. The results show that the maximum distance is limited by the emissions of polycyclic aromatic hydrocarbons by road trucks. Finally, the paper discusses the results considering the energy efficiency of WtE processes and proposes alternative WtE strategies to increase the level of public acceptance
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
ASSESSMENT OF THE ENVIRONMENTAL PERFORMANCE OF HIGHER EDUCATION INSTITUTES: THE CASE OF ITALIAN UNIVERSITIES
No full textHigher education institutes (HEIs) contribute to educate future generations of scientists, decision makers and politicians. To overcome the present and future challenges involving environmental protection and climate change, the education of responsible individuals who may play a key role in improving global environmental sustainability levels is crucial. To achieve this goal, HEIs themselves must be promoters of values and ideas to support sustainable development. To start, HEIs should give a good example to students and society, provide best practices in terms of environmental conservation and sustainability, and be models to follow in terms of resource efficiency, energy use and waste management. However, the commitments and efforts of HEIs in this field must be measured in an unbiased way, to ensure a correct interpretation of their achievements, and with reference to the strategies adopted by universities. This paper aims to present the results of a survey on Italian universities in terms of energy consumption and related greenhouse gas (GHG) emissions, water use and waste production. These items will be presented in a temporal trend relative to specific parameters that help to decontextualise the results from the location of HEIs. Where available, information on the strategies implemented by HEIs to improve their performance will be reported and the results will be discussed. The results show improvements in terms of thermal energy consumption, water consumption and GHG emissions, whose decrease was favoured by a progressive shift towards renewable sources of electricity. Clear conclusions on waste production are not possible due to the insufficient amount of data. The indicators analysed here may be useful to important ranking systems, developed to assess HEIs’ performance worldwide, since the use of indicators that do not depend on the geographical context where HEIs are located may decontextualise the results and allow comparing different HEIs in an unbiased way
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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