1,721,002 research outputs found
Innovative materials for heavy metals and hydrocarbons removal from wastewater of oil industry
Full text linkRecovery of wastewater is one of the most important challenges for our future due to the endemic scarcity of this resource in many parts of the world. Wastewaters derived from petrochemical activities represent a large share of water linked to human activities. This is due to the centrality of oil for the global economy and the great water consumption for all the linked activities, that goes from extraction to refinery. The adsorption technologies providing zeolite materials, both microporous and mesoporous, present a good choice for water remediation due to their simplicity, effectiveness, long term stability and adaptability. The development of new materials for adsorption technology is the main goal of this thesis. In particular, some microporous materials for heavy metals uptake and several mesoporous materials for hydrocarbons confinement have been characterized by structural and process point of view. Kinetic and thermodynamic (adsorption isotherms) behaviour of all material with different organic and inorganic pollutants is deeply investigated. Mathematical models to describe adsorption kinetics and isotherms have also been developed in order to obtain important parameter useful for the transaction from bench-scale to the next pilot scale. Structural characterization has been carried out to understand which changes occurred in material structure after adsorption of contaminants, the host-guest interactions and thermal stability of materials. This double characterization work was planned to screen a set of known materials and compare their performances to those of a new mesoporous amorphous material: the mesoporous silica-alumina or MSA. Indeed, the ultimate aim is to use MSA as multitalented material for simultaneous removal of heavy metals and hydrocarbons from wastewater derived from oil extraction, oil refining or oil contamination
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
Advancements in sample preparation for performing elemental analysis of human hair by inductively coupled plasma mass spectrometry
No full textThe determination of minerals and trace elements in human hair is potentially useful for assessing an individual's health status and monitoring occupational and environmental exposure [1,2,3]. Moreover, human hair is a stable matrix that presents numerous advantages for human biomonitoring, such as easy collection, low cost, easy transport and storage, and information about short- and long-term exposure. Consequently, its use in toxicological, clinical, environmental, and forensic investigations is growing and becoming more extensive. On the other hand, owing to the lack of standardized hair analysis procedures (including sample treatment methods), it is difficult to compare and interpret the results (intervals and reference values) from different studies and reach significant conclusions. In particular, recent reviews have revealed that analytical characteristics (detection/quantification limits and accuracy) are scarcely reported. Analyte loss, contamination, and/or interferences may also lead to a decrease in the analytical accuracy of the results. Incomplete decomposition of the hair samples involves an appreciable amount of residual carbon (C) in the resulting sample solution. In inductively coupled plasma spectrometry (ICP) techniques, this leads to the increased signal of some elements by carbon charge transfer reactions, especially for elements that have similar ionization potentials to that of C [4]. Another source of error in hair analysis by ICP with mass spectrometry (ICP-MS) is the interference caused by the residual acidity in the digests, difference between the viscosity and acid concentrations of the calibration and sample solutions, and the presence of polyatomic ions in the plasma [4]. Considering these aspects, the aim of this study was to optimize and validate a fast screening analytical method for the determination of 40 elements (Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, Sb, Se, Si, Sn, Sr, Te, Ti, Tl, U, V, W, Zn, and Zr) in small-size (0.02 g) human hair specimens. The samples were subjected to HNO3/H2O2 (2:1) digestion in an open vessel heated in a water bath and subsequently analyzed by ICP-MS equipped with a collision-reaction interface [4]. This method was used to determine the levels of essential and toxic heavy metals in the hair of children living in the Benishangul-Gumuz region, a Developing Regional State of North-Western Ethiopia [1]. The influence of several factors in the variability of element concentrations in children’s hair (age, sex, body mass index, passive smoking, and eating habits) was also studied [1].
[1] M.L. Astolfi, G. Pietris, C. Mazzei, E. Marconi, S. Canepari, Int. J. Env. Res. Pub. He. 2020, 17, 8652.
[2] M.L. Astolfi, C. Protano, E. Marconi, L. Massimi, D. Piamonti, M. Brunori, M. Vitali, S. Canepari, Int. J. Env. Res. Pub. He. 2020, 17, 1911.
[3] C. Protano, M.L. Astolfi, E. Marconi, A. Antonucci, S. Canepari, D. Piamonti, M. Brunori, M. Vitali, Biol. Trace Elem. Res. 2020, 197, 89–100.
[4] M.L. Astolfi, C. Protano, E. Marconi, L. Massimi, M. Brunori, D. Piamonti, G. Migliara, M. Vitali, S. Canepari, Anal. Methods 2020, 12, 1906–1918
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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