1,720,999 research outputs found
Sustainable Permeable Asphalt System on Road Infrastructures
Full text linkPermeable Asphalt Systems (PAS) ensure, as well as road safety, environmental benefits by promoting the infiltration and filtration of stormwater and thus restoring the hydrological cycle. This work focuses on the evaluation of the filtration efficiency of a sustainable permeable asphalt system actually implemented on the Adriatic Bridge (Bari, Italy). In order to reach this goal, firstly, several laboratory studies for in-deep analyzed every aspect of permeable asphalt and of materials involved in the filtration processes were carried out. Hence, the first part of this work is intended to present the results obtained from these preliminary study: dry roads particulate matter (PM) samples from Apulia roads were collected and granulometrically characterized by means of mathematical model; then the clogging process within the PM loaded-permeable pavement specimens and the hydraulic conductivity reduction connected to it were observed; afterwards the pore structure of permeable pavement specimens was re- constructed by means of x-ray tomography; thereon a numerical model for determining the hydraulic conductivity of a 3D reconstructed permeable pavement specimens was developed by means of the Computational Fluid Dynamics (CFD). The findings of these studies have made a critical contribution to the development of the practical part of this work. The second part of the work is devoted to analyzing and modeling the experimental sustainable permeable asphalt system of the bridge. The system, composed of an open-graded friction-course (OGFC) and an infiltration trench, was reproduced in laboratory. The filtration efficiency was evaluated both for the individual system components and for the whole integrated system simulating various rainfall conditions. Meanwhile, quality analyses of the inflow and outflow stormwater collected directly in-situ from the system were also performed. The integrated system showed both in laboratory and in-situ good filtration properties and a high power of depletion of PM materials. In conclusion, the system, with some shrewdness, can be implemented on road infrastructures as a diffuse treatment system. Further researches are aimed at developing a numerical model able of predicting the particulate separation processes within the PAS for investigating the applicability in any context as geographical and environmental conditions change
Definizione di interventi per il controllo dell’inquinamento delle acque nel bacino urbanizzato del torrente Gravina
No full textIl presente articolo descrive uno studio finalizzato alla definizione di interventi per il controllo dell’inquinamento originato dagli effluenti urbani nelle acque del torrente “Gravina di Matera”. Nel bacino idrografico è ubicata un’importante area naturalistica, il “Parco della Murgia” (Directive 92/43/CEE “Habitat”, European Communities Natural Network); il torrente lambisce i “Sassi”, sito ampiamente noto per il rilevante interesse sociale, archeologico e religioso, e patrimonio dell’Unesco.
Lo stato naturale delle acque è oggi degradato in ampie tratti del torrente per la forte pressione antropica esercitata dalle aree urbanizzate delle città di Matera e di Altamura. Nei periodi di magra la portata idraulica è costituita prevalentemente dagli scarichi delle acque di drenaggio e delle acque reflue presenti sul bacino nelle aree urbane, industriali e commerciali.
In questo scenario, le potenzialità di un’azione pianificata di riqualificazione ambientale, correttamente impostata, divengono evidenti e consentirebbero, una volta concretizzate ed abbinate ad interventi anche di carattere architettonico, di prospettare un più conveniente uso dell’area eventualmente inserita in una struttura di parco urbano.
Lo studio, inquadrato in un piu’ ampio scenario di azioni tese alla tutela dello stato naturale del torrente nel bacino urbanizzato, è stato sviluppato attraverso un’attività preliminare di monitoraggio e di modellazione della qualità delle acque, condotta al fine di valutare lo stato ambientale, e su un’analisi tesa a verificare l’applicazione di sistemi di trattamento degli effluenti urbani, con particolare riferimento a processi naturali e terziari avanzati
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
ANALISI DELLE ROTTURE NELLE TUBAZIONI DELLE RETI ACQUEDOTTISTICHE
No full textLa riduzione delle perdite e una gestione efficiente dei sistemi acquedottistici passa anche attraverso una comprensione dei fenomeni che portano alla rottura delle tubazioni, aspetto estremamente complesso da prevedere in quando funzione di molteplici fattori che dipendono dalle proprietà fisiche della tubazioni, dalle condizioni di esercizio o da aspetti ambientali.
Nel presente lavoro si è cercato di evidenziare proprio come le condizioni climatiche siano un fattore importante nella rottura delle tubazioni. Questo è stato fatto attraverso l'indagine di 8 anni di dati in diverse reti acquedottistiche del centro-nord Italia.
L'analisi dei dati ha quindi consentito di evidenziare come il legame tra numero di rotture e condizioni ambientali sia molto forte. Questo accade maggiormente per alcuni materiali come il polietilene dove la correlazione tra temperatura e numero di rotture è evidente. Sicuramente le condizioni di scarsità di precipitazioni e temperature alte portano a variazioni delle caratteristiche del terreno che rinfianca la tubazione venendo quindi a modificare l'azione di sostegno alla tubazione stessa, così come possono indurre dilatazione e quindi tensioni nelle tubazioni stesse.
Questo tipo di indagine può avere aspetti ingegneristici importanti sia quando si definiscono le condizioni di posa delle tubazioni sia quando si vogliono adottare o calibrare modelli matematici di previsione delle rotture, fondamentali per pianificare gli interventi di sostituzione delle tubazioni e di ricerca perdite
COMPARISON OF URBAN RETROFITTING SCENARIOS FOR SUSTAINABLE STORMWATER CONTROL: A CASE STUDY IN MILAN, ITALY
Full text linkThe traditional approach of stormwater management in urban areas frequently affected by floods has proven to be unsustainable for the growing urbanization scenario as well as not adapted to provide climate change resilience. In the spirit of water sensitive cities, a stormwater management change is necessary, moving from pipe-based conveyance system to solutions able to manage at its source by small scale structures sprawled over the entire watershed, in a collection of systems and practices known as SuDs (Sustainable Urban Drainage Systems). These techniques provide several benefits not only related to risk mitigation but also to water quality and ecosystem services enhancement that make cities resilient also in terms of climate change. Currently stormwater and land use regulations mostly define a flow-limit to reduce discharge on the sewer systems. In this way, however, the search for further benefits is not encouraged. Flow-limit restrictions are obtained through storage control systems designed with design-storm methods that neglects the effect of pre-filling reducing the storage capacity before a new rainfall event. This research compares different stormwater management solutions for a new developed area located in Bresso municipality, in the metropolitan area of Milan (Italy), within the Seveso River watershed. The proposed scenarios go from no intervention to completely avoiding discharge on the sewer network with the implementation of stormwater control structures (permeable pavements, green roofs, retention basins, among others). The storage facilities are designed with a traditional design method and then their performance is evaluated with rainfall-runoff and routing model continuous simulations, also used to compare the different scenarios. The simulations confirm that is possible to reach more restrictive goals beyond the flow-limit regulations using stormwater controls structures that also provide multiple benefits and have significant effects in terms of hydraulic risk mitigation at watershed level. Continuous simulation shows that the effect of chained rainfall events can however reduce controls performance and should be considered when designing
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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