1,720,957 research outputs found
Influence of solid–liquid compositions and contact time during maturation on the properties of artificial peloids for use in pelotherapy
No full textPeloids are natural therapeutic muds or clays used in balneotherapy and other health treatments. The aim of this study is to prepare and qualify three artificial peloids by the maturation for 360 days of some Tunisian smectitic clays with a naturally chlorinated sodic mineral water from a spring in Korbous, Tunisia. This allows us to understand the behavior and the physicochemical changes that affect the clays during maturation process, whose purpose is to provide suitable raw materials as a solid phase for peloids preparation. The results showed that parameters such as mineralogy, geochemistry, granulometry, cation exchange capacity, consistency parameters (Atterberg limits and plasticity index), specific surface area, cooling kinetics and pH are all affected by the geochemistry of the thermal water used during maturation. Mineralogical modifications are mostly concerning the clay minerals' contents, particularly smectite, and subordinately the dissolution of gypsum and the neoformation of halite. Improvement of plasticity index and cooling kinetics can be explained by the ability of water molecules, and especially cations, to diffuse into the clay particles. Main exchangeable cations are Na+ and Ca2+, along with Mg2+ and K+, which promote swelling and better water retention and consequently of heat in thermal spa treatments. Chemical composition of major elements is closely linked to their mineralogical compositions, and also to the chemical composition of the thermal water used in their maturation. Safety profiles of the peloids obtained at different maturation times were evaluated, in particular their content of potentially toxic elements such as arsenic
Green Synthesis of Iron Nanoparticle/Clay Composites and Their Effectiveness in Orange II Dye Removal Efficiency
No full textThis paper presents a study on orange II sodium salt (OII) degradation based on iron nanoparticles supported by kaolinite clays. The effects of nanoscale iron and initial dye concentration, as well as hydrogen peroxide dosage in a Fenton process, on the degradation of OII were studied. These nanoparticles were synthesized by green methods using coffee bean extract as a natural antioxidant for this process. Aqueous iron chloride was mixed with coffee extract, which is rich in antioxidants, and these antioxidants are responsible for the reduction of metal compounds into nanoparticles. The composite iron nanoparticle-kaolinite composite was synthesized from an aqueous FeCl3 and kaolinite solution with the added coffee bean extract. The results showed that OII removal efficiency increased with the amount of iron nanoparticles (n-Fe) alone and with the amount iron-supported-kaolinite composite. By increasing the amount of composite, the adsorptive surface area increases as well as the number of active sites, which determine the higher removal efficiency. Regarding H2O2 dosage, dye removal was more efficient at lower quantities: 62% removal efficiency with addition of 10 mL H2O2, while for the test conducted with 20 mL H2O2, removal efficiency was 47%. A possible reason for this behavior can be the n-Fe/ H2O2 ratio, which influences the production of degradation products and hinders the degradation
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
Potential of a Tunisian Natural Clay to Remove Cationic and Anionic Dyes From Polluted Waters
No full textThe objective of this study is to show the adsorption power of Tunisian smectitic clay from Jebel Aidoudi from the region of El Hamma (southern Tunisia). A cationic dye (Methylene Blue: MB) and an anionic dye (Orange II: OII) are used to determine the maximum absorbability of clay. Physico-chemical characterization tests (XRD, XRF, SBET) on the clay sample were performed. The experimental results showed that the optimal contact time of adsorption is 40 min (91.35% and 51.87%, respectively, for MB and OII). An increase in the retention rate of the dyes was noted by varying the adsorbent rate from 0.06 g to 0.12 g. The experimental results showed that the retention was strongly influenced by the pH of the medium (a high adsorption rate of MB at basic pH and a high adsorption rate for OII at acidic pH). The adsorption capacities are well described by the Langmuir isotherm. The pseudo-second order model is the most reliable for determining the order of absorption kinetics of MM and OII by this smectitic clay
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
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