1,720,974 research outputs found
Electrodeposition of magnetic smco films from deep eutectic solvents
No full textSmCo alloys have attracted attention for their high Curie temperature, magnetic anisotropy and relatively high saturation magnetization. Because of the very negative reduction potential of Sm in aqueous solution, its electrodeposition is problematic due to strong hydrogen evolution at the cathode surface. Deep eutectic solvent solution of 1 choline chloride: 2 ethylene glycol is studied as alternative solution to aqueous solvents for the electrodeposition of SmCo alloys. This study is focused on the deposition process of the alloy; variable Sm% contents are obtained depending on the experimental conditions e.g. bath formulation, deposition voltage and stirring condition
Electrodeposition of ZnNi alloys from ethylene glycol/choline chloride based ionic liquid
No full textZinc alloys containing transition metals (Ni, Co and Fe) have attracted the attention because of their high corrosion resistance. In the framework of non-aqueous solution, improved deposit quality and process efficiency are expected with respect to aqueous ones. In this work, eutectic mixture of molar ratio 1 choline chloride: 4.5 ethylene glycol is considered. Codeposition of zinc and nickel is studied as a function of the metal salts concentration; particular attention is paid to the formation of Zn rich alloys (15-25 % wt. Ni). Metastable -ZnNi with short-range order has been obtained
A pulsed discharge system with an intermitting partial charge for improved battery efficiency
No full textn this work, a lead-acid battery pack with a nominal energy of ~23.2 kWh at 1C is tested under different loading profiles, both constant and pulsed, aiming to improve the overall cycle efficiency. A partial charge phase is implemented in a pulse discharge profile, typically comprising the alternation between work and rest (idle) phases. The partial charge current, duration, and minimum/maximum cell voltage achieved during the partial phase are investigated, highlighting the effects on the overall battery performances. The investigated discharge approach can improve both energetic and faradaic efficiencies with respect to the constant current discharge up to ~10 %
Electrodeposition of magnetic SmCo films from deep eutectic solvents and choline chloride-ethylene glycol mixtures
Full text linkSuitability of mixtures based on ethylene glycol and choline chloride is evaluated for the electrodeposition of magnetic SmCo alloys. Deep eutectic solvents (DES) are characterized by a wide electrochemical window, allowing the electrodeposition of metallic elements having a highly negative reduction potential. Electrodeposition of unconventional metals with reduction potential well below hydrogen evolution one is, in principle, feasible (e.g. Sm). Moreover, the limited presence of water during the growth of SmCo alloys may reduce oxidation and consequently improve the magnetic properties with respect to the employment of an aqueous bath. Deposits composition is strongly affected by process parameters and bath composition. Increasing choline chloride concentration and/or adding glycine to the solution allows to achieve higher Sm content in the deposit. Potentiostatic electrodeposition has been carried out in a conventional three electrodes cell, with potential interval selected from â0.7 V vs Ag wire to â0.95 V vs Ag wire, keeping the bath under stirring at 70°C. Magnetic SmCo films with composition from 0 to 50 wt% Sm have been obtained with coercivity up to 270 Oe
Electrochemical Characterization of Magnetite (Fe3O4) Nanoaggregates in Acidic and Alkaline Solutions
Full text linkThe electrochemical behavior of magnetite (Fe3O4) aggregates with submicrometric size is investigated. Specifically, cyclic voltammetry tests were performed in both acidic (pH ∼ 4.5) and alkaline (pH ∼ 12.8) solutions, exploiting a conventional three-electrode cell. In the first case, the working electrode was made of a glassy carbon substrate loaded with magnetite nanoaggregates, forming a continuous film. In a second configuration, magnetite nanoaggregates were dispersed in solution, kept under stirring, as a fluidized electrode. The latter approach showed an increase in the electrochemical response of the particles, otherwise limited by the reduced active area as in the former case. Electrochemical-atomic force microscopy (EC-AFM) investigation was carried out in an acidic environment, showing the topography evolution of nanoaggregates during the electrochemical characterization. X-ray diffraction (XRD) analysis was carried out to evaluate the microstructural variation in the Fe3O4 electrodes after cathodic polarization tests in an alkaline environment
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
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