1,720,966 research outputs found
Magnetically recyclable TiO2/MXene/MnFe2O4 photocatalyst for enhanced peroxymonosulphate-assisted photocatalytic degradation of carbamazepine and ibuprofen under simulated solar light
No full textIn this study, a novel TiO2/Ti3C2/MnFe2O4 magnetic photocatalyst with dual properties, enabling (i) improved photocatalytic degradation with PMS activation under simulated solar light and (ii) magnetic separation after the degradation process in an external magnetic field was developed and applied for the efficient photodegradation pharmaceutically active compounds (PhACs) frequently present in wastewater and surface waters worldwide. MXene was used as a Ti precursor for anatase/rutile synthesis and as a co-catalyst in the photodegradation process. Manganese ferrite with ferrimagnetic properties was coupled with the TiO2/Ti3C2 composite to facilitate the magnetic separation after the purification process in an external magnetic field. Moreover, MnFe2O4 was used for PMS activation, producing & BULL;SO4- radicals with a strong oxidation ability and higher redox potential of 2.5-3.1 V (vs. NHE) than & BULL;OH radicals with a standard oxidation-reduction potential of 2.8 V. The effect of the manganese ferrite content in the composite structure (5 wt% and 20 wt%) on the physicochemical properties and photocatalytic activity of the magnetic photocatalyst was investigated. Furthermore, the most photocatalytic active composite of TiO2/MXene/5%MnFe2O4 was used for peroxymonosulphate-assisted photocatalytic degradation of ibuprofen and carbamazepine. The effect of peroxymonosulphate concentration (0.0625 mM, 0.125 mM, and 0.25 mM) and the synergistic effect of PMS activation on photocatalytic degradation was studied. Based on the obtained results, it was found that TiO2/MXene/5%MnFe2O4/PMS process is an efficient advanced treatment technology for the oxidation of emerging contaminants that are not susceptible to biodegradation. Carbamazepine and ibuprofen were completely degraded within 20 min and 10 min of the PMS-assisted pho-todegradation process under simulated solar light. The trapping experiments confirmed that & BULL;SO4- and & BULL;O2- are the main oxidising species involved in the CBZ degradation, while & BULL;SO4- and h+ in the IBP degradation. Furthermore, introducing interfering ions of Na+, Ca2+, Mg2+, Cl-, and SO42- in the model seawater did not affect the removal efficiency of both pharmaceuticals. In terms of reusability, the performance of the TiO2/MXene/5% MnFe2O4/PMS photocatalyst was stable after four subsequent cycles of carbamazepine and ibuprofen 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
Magnetic carbon Fe3O4 nanocomposites synthesized via magnetic induction heating
Get PDFMagnetic Induction Heating (MIH) of magnetite nanoparticles is employed as a novel synthesis procedure of carbon based magnetic nanocomposites. Magnetic nanoparticles (Fe3O4) and fructose (1:2 weight ratio) were mechanically mixed and submitted to a RF magnetic field (305 kHz). The heat generated by the nanoparticles leads to the decomposition of the sugar and to the formation of an amorphous carbon matrix. Two sets of nanoparticles, with mean diameter sizes of 20 and 100 nm, are comparatively analysed. Structural (X-ray diffraction, Raman spectroscopy, Transmission Electron Microscopy (TEM)), electrical and magnetic (resistivity, SQUID magnetometry) characterizations confirm the nanoparticle carbon coating through the MIH procedure. The percentage of the carbonaceous fraction is suitably increased controlling the magnetic heating capacity of the magnetic nanoparticles. The procedure enables the synthesis of multifunctional nanocomposites with optimized properties to be applied in different technological fields. Particularly, Cr (VI) removal from aqueous media is presented employing the carbon nanocomposite with 20 nm Fe3O4 nanoparticles.The research was funded by MCIN/AEI/10.13039/501100011033, Grant PID2020-116321RB-C21. L. Cervera-Gabalda acknowledges Public University of Navarre for her PhD contract “Contratos Pre-doctorales adscritos a Grupos e Institutos de Investigación de la Universidad Pública de Navarra”
Aportaciones de las técnicas electroanalíticas a la detección y caracterización de nanopartículas de Oxido de Cerio(IV) en suspensión
Get PDFLas nanopartículas de óxido de cerio son un novedoso material con aplicaciones muy prometedoras en campos actualmente tan críticos como la remediación medioambiental, purificación de aguas, energías renovables y medicina. La multitud de aplicaciones se debe a su peculiaridad capacidad de almacenar o liberar oxígeno en función de los requerimientos de oxígeno del lugar donde se encuentran. A su vez, esta capacidad depende del tamaño de las partículas de óxido de cerio, llegando a ser máxima cuando su tamaño se reduce a unos pocos nanómetros de diámetro. Las nanopartículas de óxido de cerio sobre todo han sido utilizadas para diversas aplicaciones como catalizadores en la industria del automóvil, en la remediación ambiental y purificación del agua y en biomedicina. Estas nanopartículas acaban en el medioambiente, donde no se conoce bien su ciclo de vida y por tanto no se conoce cómo pueden afectar a los seres vivos. Sí que se sabe que sus propiedades redox dependen de su historia previa y del medio en que se encuentran, actuando unas veces como oxidantes y otras como reductores, afectando decisivamente al ciclo de los radicales libres. Estas propiedades también están moduladas por su superficie y su tamaño. Por tanto, resulta de gran interés desarrollar metodología que permita obtener datos sobre su forma, tamaño y características químicas. Las técnicas electroanalítcas constituyen una aproximación al problema muy interesante ya que permiten el estudio de las nanoparatículas en suspensión, con un mínimo cambio en sus condiciones, lo que permite hacerse una ida de cómo interactuarían en ese medio ante oxidantes y reductores. En este trabajo se explorara el uso de la voltametría y la cronoamperometría para estudiar la influencia del tamaño en las propiedades químicas de las nanopartículas de óxido de cerio (IV) en suspensión
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
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