1,720,967 research outputs found
Phosphate Removal from Aqueous Solution by Hydrous Iron Oxide Freshly Prepared Effects of pH, Iron Concentration and Competitive Ions
No full textAbstractIn the present work, the phosphate removal by hydrous iron oxide freshly prepared is studied. Experiments were conducted to study the effects of pH, iron concentration and the presence of sulphate, chromate, oxalate and certain metallic ions. Infrared spectroscopic analyses were performed to characterize the mechanism of phosphate interaction with the hydrous oxide in the absence and in the presence of the competitive ions. The results of macroscopic analyses show that the phosphate uptake is related to pH. The effect of iron concentration, suggests a certain saturation of adsorption sites. The effect of oxalate ions is more significant than those of chromate and sulphate ions. The presence of zinc and copper decreases the phosphate removal at pH > 7. In the absence of the other ions, the IR spectra of the solid samples show a broad band in the surrounding of 1030cm-1, characterizing the tetrahedral symmetry of phosphate. Among the studied anions, only chromate has an effect on the mechanism of phosphate ion retention by hydrous iron oxide freshly prepared
Characterization of Chromium (VI) Interaction with Rivers Sediments-In Relation to the Composition
No full textThe aim of the present work is to evaluate the mobility of chromium (VI) in aquatic systems by studying its interaction with different rivers sediments. The studied sediments were collected from the river Essouk which flows through a mining area in Skikda, and from the river Hemimime which flows through an industrial area in Constantine. The Cr(VI) fixation experiments on the studied sediments were carried out in batch. The results obtained show that the fixation of Cr(VI) is mainly related to the composition of the sediments. Sediments with a predominance of schwertmannite fix Cr(VI) better. The predominance of jarosite or calcite in sediments, implies a low Cr(VI) retention capacity. In the three cases, the kinetics of Cr(VI) fixation follows the pseudo-second order kinetic model. The adsorption isotherm is best described by the Freundlich model in the case of the jarosite predominance and by the Langmuir model in the case of the schwertmannite or the calcite predominance
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
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
- …
