1,720,957 research outputs found
Understanding and tuning Fe‐doping on Zn–Fe layered double hydroxide particle and photocatalytic properties
No full textZn-based layered double hydroxides (LDHs) are promising photocatalytic materials, but their synthesis faces environmental and economic challenges. Oxidative ionothermal synthesis (OIS) offers a green route for zinc oxide synthesis using ionic liquids. To reduce costs, the OIS method uses recovered zinc-containing mixed metal systems, such as electric arc furnace dust, instead of pure metallic Zn. Understanding the interaction of Zn with impure metals during oxidation is essential. This study employs 1-Butyl-3-methylimidazolium chloride ([BMIM]Cl) as the solvent and Fe-doped metallic Zn, the most common waste-stream metal, as the starting material. This study applies quartz crystal microbalance with dissipation to monitor product formation, and X-ray diffraction and scanning electron microscopy to characterize composition and morphology. Results show that FeCl2 doping accelerates the reaction, transforming simonkolleite to Zn–Fe LDH with tunable morphologies. A reaction mechanism for Zn in [BMIM]Cl with FeCl2 is proposed. Photocatalytic hydrogen production tests reveal a favorable hydrogen evolution rate of 20.9 μmol h−1 g−1 with 0.45 M FeCl2 doping, attributed to improved surface structure and crystallinity of the hydrotalcite
Interfacial phenomena in pharmaceutical process development
Full text linkInterfacial phenomena are of crucial importance in both pharmaceutical process development and drug product development. Inverse Gas Chromatography (IGC), is an adsorption-based technique providing a versatile framework for the investigation of interfacial phenomena. In the light of fundamental concepts of thermodynamics, new IGC protocols have been developed enabling the accurate determination of the surface energy and the surface energy heterogeneity of crystalline materials and of the Hansen Solubility Parameter (HSP) of amorphous materials.
Experimental and in silico studies are deployed to reveal the importance of sample preparation in the accuracy of IGC measurements. In this context, Monte Carlo simulations were developed to support the experimental findings. The importance of spreading pressure in IGC measurements is investigated as well. A separate chapter discusses the importance of temperature and carrier gas flow rate in the measurement of HSP, of amorphous materials. Results obtained from the three chapters, are used, alongside with the results from complimentary techniques, to investigate the facet specific interactions of copovidone solutions, with macroscopic single crystals of p-monoclinic carbamazepine. Very intriguing findings are reported, highlighting among other things, the correlation between the aggregation behaviour of the polymer and wettability. In the next chapter IGC measurements are deployed, among other techniques, to investigate the mechanism of dehydration induced concomitant polymorphism of carbamazepine dihydrate. As part of this chapter a novel bioinspired crystal growth technique has been developed, enabling the growth of macroscopic hydrates of poorly water-soluble molecules.
Overall this thesis, constitutes a unique piece of work combining a plethora of characterisation techniques, with novel in silico tools to investigate interfacial phenomena, of high importance in pharmaceutical industry. It highlights the importance of fundamental notions of surface thermodynamics in the development of an in-depth understanding of interfacial phenomena and it reveals the prospects of IGC as a potential game changer in pharmaceutical process development and drug product development.Open Acces
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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