1,721,032 research outputs found
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
A Kinetic Study of Silver Extraction from End-of-Life Photovoltaic Panels through Gold-REC1 Process
No full textRecycling materials from end-of-life devices and products is becoming increasingly a fundamental activity for the sustainable development of nations. With the return from the market of immense quantities of photovoltaic panels at the end of their life, it is essential to foresee processes for recovering and valorizing all the raw materials present in them to avoid wasting important flows of raw materials. This research introduces a novel process aimed at the recovery of silver and silicon from end-of-life photovoltaic panels. The leaching efficiency and kinetics of ground cake powder in sulfuric acid, ferric sulfate, and thiourea were investigated in the leaching system. In particular, the influences of significant parameters, including particle size, leaching temperature, and stirring rate, on the extraction kinetics were analyzed using the shrinking core model. The results showed silver dissolving mechanisms, in which more than 90% of silver recovery at 60 min of reaction time and 99% at 120 min was achieved (120 rpm, 53–125 μm, and 40 °C). The significant effect of the leaching temperature suggests that the process is under the control of the chemical reaction. Moreover, these results were confirmed by the regression analysis of the experimental data with the shrinking core model. It can be concluded that this newly proposed process, called Gold-REC1, allows the recovery of Ag and Si (solid residue from the process) with extremely high yields and rapid kinetics. The obtained results can provide fundamental data for developing end-of-life photovoltaic recycling on an industrial scale
Leaching of Rare Earths from End-of-Life NdFeB Magnets with Citric Acid Using Full Factorial Design, Response Surface Methodology, and Artificial Neural Network Analysis
Full text linkIn recent years, the increasing demand and rising prices of rare earth elements (REEs), along with their attendant supply risk (about 95% of these elements are supplied by China), have led the European Commission to consider REEs as critical raw materials. Developing and optimizing processes for recovering REEs from secondary sources such as NdFeB magnets is fundamental in this context. A novel method to recover REEs by leaching with citric acid and subsequently separating these elements using the solvent extraction method has been introduced. Therefore, this research investigates the leaching efficiency of REEs, Fe, and B from NdFeB magnets. A full factorial design, with 18 experimental setups, was conducted to optimize the citric acid concentration (1–3 mol/L), leaching time (1–3 h), and solid–liquid ratio (5–10%wt./vol.). All tests were carried out at room temperature and 150 rpm. Different optimizations (response surface methodology (RSM) and artificial neural network (ANN) analysis) are used to maximize the REEs’ leaching efficiency. RSM resulted in a maximum extraction yield of total rare earth elements (TREEs) of about 89% in the investigated experimental plan. This result is similar to that for ANN analysis (about 86%), but more accurate than that for RSM. In fact, for the ANN, an overall R-value higher than 0.99 was obtained. This result indicates that the developed ANN can be used as an accurate model for estimating the leaching efficiencies of REEs from NdFeB magnets
Innovative sulfation strategy for efficient recovery of rare earth elements from spent fluorescent lamp powder
Full text linkThe recovery of rare earth elements (REEs) from spent fluorescent lamp phosphors is essential for resource sustainability and circular hydrometallurgy. While yttrium (Y) and europium (Eu) can be recovered through simple acid leaching, extracting cerium (Ce), lanthanum (La), and terbium (Tb) from green phosphors is challenging due to their resistance to dissolution. This study presents a novel sulfation-based process at relatively low temperatures to selectively recover REEs, particularly Tb, while minimizing energy consumption and environmental impact by preventing sulfuric acid and mercury evaporation. Initially, sulfuric acid leaching selectively recovered most of Y and Eu, leaving other REEs in the solid residue. These elements were then precipitated as a nearly pure REE oxalate mixture (>99 % purity). The effects of sulfation time, temperature, and acid-to-powder weight ratio were optimized using Response Surface Methodology (RSM). Sulfation at 150 °C for 5 h enabled the recovery of nearly 100 % Ce and Gd, 98.01 % La, and 98.15 % Tb through water leaching. The mixed oxalate precipitate, enriched in La, Ce, and Tb, exhibited >98 % purity. SEM analysis revealed the formation of flower-like mixed REE oxides after calcination. This process achieved high recovery efficiencies of 99.98 % Y, 100 % Eu, 99.92 % Ce, 97.22 % La, 97.68 % Tb, and 99.97 % Gd. By using only sulfuric and oxalic acid, it aligns with sustainable hydrometallurgy, reducing chemical diversity and enabling acid regeneration. This study provides an efficient, environmentally friendly approach for REE recovery from phosphor waste
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