1,720,957 research outputs found
Disinfection By-Products and microbial occurrence in an Italian Drinking Water Distribution Network: cluster analysis for sampling point selection
Full text linkDrinking Water Distribution Networks (DWDNs) should be managed balancing chemical and microbiological risks. Our goal is to develop a model linking microbiological and chemical parameters to the disinfection operating parameters as support management tool. Since the case study we focused on comprises 27 drinking water treatment plants (DWTPs) feeding a unique DWDN, the number of sampling points to be monitored for the model is huge. To reduce the numerosity of the sampling points without losing information, we performed a cluster analysis to identify groups of DWTPs with similar characteristics, to be considered as representative. Data were preprocessed to identify two values for each DWTP, proxy of the microbial and chemical risks: (i) probability of indicator microorganisms’ enumeration, and (ii) median of total trihalomethanes (TTHMs).
Four clusters were identified, from which one DWTP was selected. Then, we planned the monitoring campaign, that will start in mid-June and last for 1-year
Chemical and microbiological risk-based optimization of disinfection and monitoring: a meta-model approach
Full text linkThe proper operation of drinking water distribution networks (DWDN) requires an optimal equilibrium between chemical and microbiological risk. In disinfected DWDNs a trade-off needs to be found in setting the concentration of residual disinfectant at the outlet of the drinking water treatment plant (DWTP) to simultaneously minimize bacterial regrowth and disinfection by-products (DBPs) formation. Since, support tools for such optimization are missing, the goal of our study was to develop a meta-model to link the disinfection operating parameters with microbiological and chemical water quality parameters. This was achieved through three steps: (i) analysis of monitoring data provided by an Italian water utility referred to 27 DWTPs; (ii) design and performing of monitoring campaigns in four DWTPs, selected as representative from the data analysis; (iii) development of a meta-model, built with data collected during monitoring campaigns
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
Management of the drinking water supply chain under climate change: new threats require new strategies
Full text linkDirect consequences of climate change are represented by both the increase of air and water
temperature and the alteration of precipitation patterns, characterized by longer droughts periods and more intense precipitations. These modifications impact on water quality, affecting the presence of microorganisms, natural organic matter (NOM), and contaminants of emerging concern (CECs). Such quality parameters are indeed crucial to provide consumers with safe drinking water, making the understanding of their variation patterns of paramount importance, to tune proper treatment schemes to minimize the human health risk. The goal of this work is to develop a holistic approach to increase the overall preparedness of the drinking water sector with respect to the need of upgrading the drinking water supply systems, comprising the plants and the distribution networks. Concerning CECs and NOM removal, the adsorption process was assessed by: (i) meta-analysis of literature isotherm data to predict CECs removal extent, and (ii) lab experiments to optimize NOM removal with respect to the type of activated carbon and the EBCT value. Then, an analysis of full-scale monitoring data from an Italian Water Utility was performed to support operators in the correct management of distribution network, identifying the most vulnerable monitoring locations with respect to both microbiological and chemical risk
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
Evaluation of UV-Chlorine Processes for Enhanced Disinfection in Drinking Water: case of study
Full text linkThe presence of natural organic matter (NOM) is the main cause for disinfection byproducts (DBP) formation, upon final chlorination. In this context, drinking water managers must maximize NOM removal and optimize chlorine dosage. In this study, water samples from surface reservoir and lab-scale treatment were combined with various unit operation and Advanced Oxidation Processes (AOPs) combinations. The impact of the experiments on the structure of the Natural Organic Matter (NOM) was evaluated as well as the formation of biodegradable compounds and the disinfection by-products (DBP) formation
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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