1,720,959 research outputs found
Coagulants removal and recovery from water clarifier sludge
No full textSeveral million tons per year of water clarifier sludge are produced in Europe, with forecasts of the figure doubling by the next decade. End disposal of reference sludge is mainly based on controlled landfilling, after conditioning to minimise the volume of solids. The conditioning operation is carried-out in acidic or alkaline media, thus also allowing for coagulants recovery (AI, Fe species). The quality of the chemicals recovered may not be sufficient to justify their reuse, e.g., to water clarification operations.
With the aim of improving the purity of coagulants recovered, a new ion exchange process for selective removal, separation and recovery of Al(III) and Fe(III) species from the clarifier sludge is presented. The IERAL (Ion Exchange Recovery of Aluminium) process is based on the use of a commercial weak electrolyte carboxylate resin (Purolite C106, from Purolite Co., UK), allowing for the removal of metals from the clarifier sludge acidic leachate (pH 3.5), followed by selective separation and recovery of the aluminium and ferric species during the resin regeneration step.
Together with the performance of a fully automated 50 L/d pilot plant, this paper reports the basic principles of the process
Procedimento per il recupero del principio coagulante dai fanghi di chiarificazione delle acque naturali e reflue
No full textRecupero di reattivi coagulanti da fanghi di chiarificazione delle acque naturali : processi basati su scambio ionico
No full textSelective recovery of coagulants from water clarifier sludge by the use of fibrous ion exchangers
No full textA new technology for removal and recovery of coagulants from water clarifier sludge has been optimized at laboratory scale pilot plant level. The process is based on the use fibrous exchangers showing good kinetic and thermodynamic performance toward coagulant species (Al, Fe) present in the acidic leachate (pH 3.5) from water clarifier sludge. The innovation allows for the solution of the environmental problem related to clarifier sludge disposal (residual solids after metals leaching are safely applied to land), and quantitative recovery of coagulants to the water potabilisation operations.
Process optimisation, by using real clarifier sludge from the Sinni River Water Works (Apulian Water Authority, S.E. Italy), was carried-out and results are illustrated in the paper. A commercial weak cation fibrous exchanger (Fiban K4) with carboxylate functionality, selectively removed aluminium and ferric species in "moving bed" unit operations with the resin re-circulating through the stationary exhaustion and regeneration baths. Resin regeneration was efficiently carried-out by the use of 0.4M NaOH solution for quantitative recovery of almost pure coagulants, ready for reuse. Together with process optimisation, the paper also reports some mechanistic indications on the fibrous resin performance toward polyvalent metal species retention at the resin functional groups
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
- …
