1,720,964 research outputs found
Apple Tree Root-Derived Biochar/Iron Oxide Triphasic Nanocomposite for Wastewater Treatment and Microwave Absorption
No full textIn this work, two major sources of pollution: (1) Water pollution due to heavy metals, and (2) Electromagnetic wave (EMW) pollution, often regarded as the fourth category of pollution (after air, water, and soil pollution) are addressed. A unique bio-based triphasic nanocomposite (Fe3O4/alpha-Fe2O3/carbon) is synthesized and its superior properties are demonstrated to address both types of environmental pollution. The nanocomposite, derived from lightweight apple tree roots, is used for Pb (II) ion removal from aqueous solutions via adsorption and magnetic separation. The biomass-derived highly porous biochar decorated with iron-oxide showed adsorption efficiency of nearly 100% and corresponding capacity of 149 mg.g-1 under optimal conditions for initial Pb (II) concentration of 50 mg.L-1. Furthermore, a remarkable adsorption capacity of 731 mg.g-1 is achieved using lower amount of the adsorbent for a slightly lower efficiency (97%). In addition, the mesoporous composite showed excellent EMW absorption efficiency with effective absorption bandwidth of 7.8 GHz and reflection loss of -61.7 dB, arising from very good impedance matching, and high dielectric and magnetic losses. This work establishes the multifunctional properties of the synthesized composite, and addresses the UN Sustainable Development Goal (SDG) 6 (Clean water and sanitation) and SDG 13 (Climate action, including pollution management). The synthesis and exploration of a multifunctional biochar/iron-oxide triphasic nanocomposite is reported to address two UN Sustainable Development Goals (SDGs), SDG 6 (Clean water and sanitation) and SDG 13 (Climate action, including pollution management). The performance of the nanocomposite as an adsorbent for the toxic heavy metal (Pb) from water, and for the absorption of harmful electromagnetic radiation is investigated. imag
Electromagnetic wave absorption performance of Fe3O4/activated carbon-natural resin nanocomposite
No full textTriphasic Inter‐Dimensional WS2/Magnetic Lithium Iron Oxide Nanocomposite for Electromagnetic Interference Shielding
No full textThe widespread use of wireless devices and telecommunication networks has given rise to electromagnetic interference (EMI) pollution that can cause data corruption, critical device failure, and detrimental effects on wildlife and human health. Developing EMI shielding materials can block these harmful electromagnetic waves. This study explores inter-dimensional composite systems composed of dielectric and magnetic phases (WS2/biphasic lithium iron oxide) for EMI shielding applications. WS2 is a 2D material with unique dielectric properties and flake-like morphology that enhances surface effects. In contrast, biphasic magnetic lithium iron oxide nanocomposites have grain-like morphology with greater magnetic losses. The formation of interfaces between these two phases with different morphologies and dimensionalities leads to enhanced interfacial polarization loss. This work demonstrates that by carefully controlling the weight percentage of the two phases, and thereby the interfaces, the EMI shielding properties can be significantly enhanced. An optimum phase composition is determined that exhibits maximum shielding efficiency (SET ≈55.6 dB at 12.4 GHz) with high absorption shielding (SEA ≈48.8 dB at 12.4 GHz), and an absorption coefficient more than 100% higher than either end member. The studied nanocomposites, with their tunable absorption and reflection capabilities, are suitable for a wide range of EMI shielding applications
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
Co-doped MnFe2O4 nanoparticles : magnetic anisotropy and interparticle interactions
Get PDFThe effect of cobalt doping on the magnetic properties of Mn1−xCoxFe2O4 nanoparticles was investigated. All samples consist of ensembles of nanoparticles with a spherical shape and average diameter of about 10 nm, showing small structural changes due to the substitution. Besides having the same morpho-structural properties, the effect of the chemical composition, i.e., the amount of Co doping, produces marked differences on the magnetic properties, especially on the magnetic anisotropy, with evident large changes in the coercive field. Moreover, Co substitution has a profound effect on the interparticle interactions, too. A dipolar-based interaction regime is detected for all samples; in addition, the intensity of the interactions shows a possible relation with the single particle anisotropy. Finally, the sample with the strongest interaction regime shows a superspin glass state confirmed by memory effect dynamics
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