1,720,956 research outputs found
Simultaneous Adsorption of Heavy Metals from Roadway Stormwater Runoff Using Different Filter Media in Column Studies
No full textStormwater runoff from roadways often contains a variety of contaminants such as heavy metals, which can adversely impact receiving waters. The filter media in stormwater filtration/infiltration systems play a significant role in the simultaneous removal of multiple pollutants. In this study, the capacity of five filter media—natural quartz sand (QS), sandy soil (SS) and three mineral-based technical filter media (TF-I, TF-II and TF-III)—to adsorb heavy metals (Cu, Pb and Zn) frequently detected in stormwater, as well as remobilization due to de-icing salt (NaCl), were evaluated in column experiments. The column breakthrough data were used to predict lifespan of the filter media. Column experiment operated under high hydraulic load showed that all technical filters and sandy soil achieved >97%, 94% and >80% of Pb, Cu and Zn load removals, respectively, while natural quartz sand (QS) showed very poor performance. Furthermore, treatment of synthetic stormwater by the soil and technical filter media met the requirements of the Austrian regulation regarding maximum effluent concentrations and minimum removal efficiencies for groundwater protection. The results showed that application of NaCl had only a minor impact on the remobilization of heavy metals from the soil and technical filter media, while the largest release of metals was observed from the QS column. Breakthrough analysis indicated that load removal efficiencies at column exhaustion (SS, TF-I, TF-II and TF-III) were >95% for Cu and Pb and 80–97% for Zn. Based on the adsorption capacities, filtration systems could be sized to 0.4 to 1% (TF-I, TF-II and TF-III) and 3.5% (SS) of their impervious catchment area and predicated lifespan of each filter media was at least 35, 36, 41 and 29 years for SS, TF-I, TF-II and TF-III, respectively. The findings of this study demonstrate that soil—based and technical filter media are effective in removing heavy metals and can be utilized in full-stormwater filtration systems
Österreichische Wasser- und Abfallwirtschaft / Filtermaterialprüfung: Anwendung der ÖNORM B 2506 Teil 3 für das hochrangige Straßennetz
No full textVerkehrsflächenabflüsse können mit organischen und anorganischen Stoffen belastet sein und als verunreinigt gelten, sodass sie vor Einbringung in den Untergrund gereinigt werden müssen. Die Belastungen stammen bzw. entstehen aus Abgasnebenprodukten, Reifen‑, Karosserie- und Fahrbahnverschleiß, Abflüssen aus Niederschlägen, nasser und trockener Deposition und Fahrbahninstandhaltungsarbeiten. Im ÖWAV-Regelblatt 45 und in der ÖNORM B 2506, Teil 1 und 2 wird der Stand der Technik der Reinigung vor Versickerung in den Untergrund mit Bodenfiltern bzw. „technischen Bodenfiltern“ (ÖNORM) und „technischen Filtern“ (ÖWAV-RB 45) beschrieben. Die Kriterien der Mindestleistungsfähigkeit und deren Prüfung wurden in der ÖNORM B 2506, Teil 3 festgelegt. Da sowohl in der ÖNORM B 2506, Teil 1 und 2 als auch im ÖWAV-RB 45 die hochrangigen Straßen ausgenommen wurden, sollen in diesem Artikel die Grundlagen der ÖNORM B 2506, Teil 3 erläutert und ihre Anwendbarkeit auch auf hochrangige Straßen aufgezeigt werden. Es konnte gezeigt werden, dass aufgrund der in der ÖNORM B 2506-3 gewählten strengen Prüfbedingungen und Prüfkriterien die Prüfung der technischen Filtermaterialien aus wissenschaftlicher Sicht geeignet sind, auch die Anforderungen an die Reinigung von Straßenabwässern von hochbelasteten Straßen mit hohen durchschnittlichen täglichen Verkehrsbelastungen (JDTV), wie jenen des hochrangigen Straßennetzes, zu erfüllen. Es sei noch darauf hingewiesen, dass die Prüfung der technischen Filtermaterialien nach ÖNORM B 2506-3 für die Versickerung in das Grundwasser erstellt wurde.Street runoff can be contaminated with organic and inorganic substances, and therefore have to be treated before being infiltrated in the underground. The contaminations are from tires, vehicles, roads, precipitation, wet and dry deposition, road maintenance work or are generated by exhaust gas products. The state of the art of cleaning before infiltration into the underground is described in the ÖWAV-Regelblatt 45 and ÖNORM B 2506 Parts 1 & 2, with the help of soil filters or “technical soil filters” (ÖNORM) and “technical filters” (ÖWAV-RB 45). The testing methods and performance criteria for such filters have been defined in ÖNORM B 2506 Part 3. Since both the ÖNORM B 2506 Parts 1 & 2 and the ÖWAV-RB 45 have exempted the high-ranking roads, this article explains the background of ÖNORM B2506 Part 3 and its applicability for run-off treatment of high-ranking roads. It has been shown that due to the strict test conditions and test criteria chosen in ÖNORM B 2506-3, the testing of the technical filter materials is from a scientific point of view also suitable, to meet the requirements for roads with high annual average daily traffic (AADT). It should be pointed out that the testing methods according to ÖNORM B 2506-3 was designed for infiltration into the underground
Performance of a filtration system equipped with filter media for parking lot runoff treatment
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
