1,720,982 research outputs found
Environmental relevance of solid by-products from Municipal Solid Waste Incineration assessed by combining magnetic and mineralogical analysis
No full textBottom (BA) and Fly Ashes (FA) from Municipal Solid Waste Incineration (MSWI) represent huge amounts of solid by-products that still pose environmental and health problems. Some routes for MSWI ashes management/reuse have been proposed (e.g., inertization, landfilling, reuse as filler, geopolymers), but not all of BA and FA hazardous components are fully understood. Precise identification of minerals from BA and FA is challenging due to several factors: high number of phases, MSWI combustion temperature, and variable chemical composition of feedstock materials. In addition, (trans)formation of magnetic iron oxides, which have been correlated with heavy metals pollution and the presence of toxic ultrafine superparamagnetic (SP) grains in a range of materials, occurs during incineration and quenching.
We have undertaken the study of BA and FA samples from Italian MSWI plants by combining magnetic and mineralogical analysis for probing mineralogy and the extent of SP grains. The BA and FA samples are characterized by narrow hysteresis curves and low coercivity (Bc, 7.2 – 14.1 mT), suggesting significant reversible component of magnetization. Also, the analysis of thermomagnetic properties shows that both BA and FA gain magnetization during cooling. The Low temperature remanent curves by Magnetic Properties Measurement System (MPMS) show magnetite-like shapes for most of samples, but the Vervey transition in FA samples is not clear probably due to the presence of oxidized/impure magnetite or unblocking of SP grains. Measurements of AC susceptibility by MPMS might support the fact of a significant contribution of SP grains in FA (FA show larger frequency dependence than BA). We performed XRD analysis on FA and BA samples, including different magnetic extracts of BA in order to shed some light on iron oxides phases. The main mineralogical phases found in BA are quartz, calcite-vaterite, melilite group minerals and plagioclase; FA contain Ca-aluminosilicates and more sulphates and chlorides with respect to the BA. Iron oxides such as wurstite, hematite, and the magnetic spinel-type iron oxides are noted both in BA and FA. The XRD pattern on BA magnetic extracts confirms that magnetite or impure spinel-type iron oxides (e.g., Mg-magnetite, Ti-magnetite, and maghemite) are in charge of their strong magnetic response. However, on the basis of previously obtained chemical analysis, the presence of impure magnetite containing Cr, Zn, Mn, and Cu cannot be ruled out neither in BA nor in FA. Rietveld refinement to assess the extent of minor metals substitution is ongoing. These preliminary observations emphasise the metastable nature of MSWI ashes and might lead to a better assessment of the environmental impact related to iron oxides
Waste recycling and hazardous elements inertization for a sustainable ceramic process
No full textA strong contribution to the sustainability of the ceramic manufacturing process can derive from the recycling of waste, especially if it contains hazardous elements (HEs). The range of secondary raw materials would be broadened to elements that, however, must undergo a total inertization into the crystalline lattice of the residual phases or in the glass matrix of ceramic bodies through the so-called ceramization process. In fact, prior any possible resorting to HEs (e.g. Ba, Co, Cr, Cu, Mo, Pb, Sb, Sn, Sr, V, Zn), their degree of inertization within different ceramic matrices have to be quantitatively assessed.
To this end, in this contribution four ceramic batches were formulated to obtain: three largely vitrified ceramic products (i.e., two different porcelain stoneware bodies and a red stoneware) and a largely unreacted body (low fired brick). These formulations, taken as ceramic standards, were then added with 10 wt% of two different type of waste: bottom ashes (BA) from MWI and an artificial waste (an aluminosilicate matrix containing all the HEs of above to simulate the BA composition). Fired products from all twelve ceramic formulations, experimented at the laboratory scale simulating the industrial tile-making process, were characterized through a combined analytical approach (QPA-XRPD, SEM, water absorption, and bulk density), and then subjected to a leaching test (EN 12457-2:2002) to evaluate the HEs mobility. Obtained results highlight a different mobilization mechanism depending on both specific hazardous element and ceramic formulation, with significant criticisms related to Mo, Cr and Sr, mostly in the largely unreacted body
Waste recycling and hazardous elements inertization for a sustainable ceramic process
No full textA strong contribution to the sustainability of the ceramic manufacturing process can derive from the recycling of waste, especially if it contains hazardous elements (HEs). The range of secondary raw materials would be broadened to elements that, however, must undergo a total inertization into the crystalline lattice of the residual phases or in the glass matrix of ceramic bodies through the so-called ceramization process. In fact, prior any possible resorting to HEs (e.g. Ba, Co, Cr, Cu, Mo, Pb, Sb, Sn, Sr, V, Zn), their degree of inertization within different ceramic matrices have to be quantitatively assessed.
To this end, in this contribution four ceramic batches were formulated to obtain: three largely vitrified ceramic products (i.e., two different porcelain stoneware bodies and a red stoneware) and a largely unreacted body (low fired brick). These formulations, taken as ceramic standards, were then added with 10 wt% of two different type of waste: bottom ashes (BA) from MWI and an artificial waste (an aluminosilicate matrix containing all the HEs of above to simulate the BA composition). Fired products from all twelve ceramic formulations, experimented at the laboratory scale simulating the industrial tile-making process, were characterized through a combined analytical approach (QPA-XRPD, SEM, water absorption, and bulk density), and then subjected to a leaching test (EN 12457-2:2002) to evaluate the HEs mobility. Obtained results highlight a different mobilization mechanism depending on both specific hazardous element and ceramic formulation, with significant criticisms related to Mo, Cr and Sr, mostly in the largely unreacted body
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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