1,720,996 research outputs found
The synthesis of zinc ferrite spinel: Determination of pH value in the co-precipitation step
No full textZinc ferrite (ZnFe2O4) nanomaterial can be facilely and conveniently synthesized via the co-precipitation method from aqueous Zn2+ and Fe3+ salt solutions using sodium hydroxide as the precipitant. However, zinc hydroxide is amphoteric and can be soluble at low and high pH values; therefore, the study on pH for simultaneous precipitation of Fe3+ and Zn2+ to achieve pure ZnFe2O4 spinel is essential. In the present study, we elaborate a theoretical equation expressing the relationship between the zinc concentration in complex formation and pH value in the co-precipitation step. Since then, we synthesized ZnFe2O4 spinel and analyzed the products via various techniques such as thermoanalysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis spectra to investigate the appropriate pH for simultaneous precipitation of Fe3+ and Zn2+. The results indicate that in a wide range of pH values, from 7 to 12, ZnFe2O4 single-phase spinel ferrite structure is formed after calcination of the precipitate at 800 degrees C, the average particle sizes (SEM, nm) of ZnFe2O4 samples are in the range of 59.5 nm-85.5 nm (but is non-linear change), and their bandgap values are similar, around 1.96 eV. However, the unwanted appearance of alpha-Fe2O3 phase, the shifting in peak position and the decrease in intensity in the XRD pattern of the spinel products synthesized at pH of 6 and 13, respectively, reflect that the stoichiometric ratio of Zn2+ to Fe3+ in the spinel products is not achieved to 1:2. Such results provide a fundamental basis for choosing the appropriate pH in synthesizing ZnFe2O4 nanoparticles with orientationally structural and optical characteristics.
Volunteers and the new tort law reform
No full textThe volunteer protection legislation in each Australian jurisdiction makes considerable changes to the law of civil liabil-ity. Advocates for volunteer protection from third party liability were quite successful in having their issue accepted by all governments in the race to provide relief from the insurance crisis. However, there are a number of provisions that can be improved now that there is time for reflection. This article outlines a number of reforms to the legislation to pro-vide better outcomes for volunteers, community organisations and persons injured through negligence
Biochar from Cyperus alternifolius Linn.: from a waste of phytoremediation processing to efficient depolluting agent
No full textPhytoremediation is one of the most powerful and viable solutions for developing countries to clean the soil and water bodies from metallic pollutants. Cyperus alternifolius Linn. (CAL), a tropical wetland plant, has been widely researched for removing harmful contaminants due to its hyperaccumulation ability. However, the waste biomass of phytoremediation processing may risk secondary environmental pollution. Thus, the preparation and application of biochar from metal-contaminated plants can be considered a new approach. In a 60-day experiment, CAL plants were irrigated with different concentrations of Zn(II) (200, 700, 1200, 1700, and 2200 mg.L-1), and then the plants were converted into biochar via the pyrolysis process. The characteristics of biochar including of surface composition and morphology, phase formation, and optical property were analyzed. The biochar enriched with Zn(II) at 1200 mg.L-1 had a bandgap value of 3.17 eV and consisted of carbon microparticles intermingled with ZnO and SiO2 nanoparticles. Furthermore, the adsorption and photocatalysis of the biochar were studied in the discolouration of methylene blue (MB), as a test reaction, with the maximum MB removal capacities of 55.2 mg.g(-1). Such results will serve as the basis for new research aiming at the potential for reusing metal-contaminated plants to produce efficient depolluting biochar.
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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