1,720,959 research outputs found
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
PREPARATION AND CHARACTERIZATION OF POLYANILINE-BASED MATERIALS FOR ELECTROCHEMICAL DETECTION OF NITROPHENOLS
Get PDFThe development of modified polyaniline (PANI)-based composites is an emerging field of advanced materials with fascinating applications such as the adsorption of metals and dyes, sensors, and biocatalysts. The electrical conductivity of PANI and its structural properties are influenced by the method used for its synthesis. Thus, if an appropriate synthetic method is employed, modified PANI-based composites can be utilized for sensor-based applications. Unfortunately, pristine PANI presents numerous challenges. It is difficult to process and has poor film-forming ability, which limits its application for practical environmental applications. The mentioned disadvantages can be addressed through formation of composites, where the use of additives or supporting materials are combined with PANI.
Chitosan (CHI) is a biopolymer that includes hydroxyl and amine functional groups that can be modified by forming a composite with PANI (CHI-PANI). Doping PANI with organic acids such as citric acid can improve its hydrophilicity and conductivity. To study the electrocatalytic properties of modified PANI-based composites, silver nanoparticles (Ag NPs) were deposited onto the composites to monitor the oxidation of 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP) in aqueous media. Cyclic voltammetry (CV) was chosen as the electrochemical method for the analytical detection of 2-NP and 4-NP.
The short-term objectives of the thesis are summarized below:
(i) To synthesize ternary composites of Ag NPs-Chitosan-PANI (Ag@CP(x), where x = 25, 50, or 75, referring to the weight fraction (%) of aniline relative to CHI) and Ag NPs-PANI-citric acid (Ag@P-CA).
(ii) To carry out structural and physicochemical characterization of modified PANI-based composites with thermogravimetric analysis (TGA), atomic absorption analysis (AAS), 13C solid-state NMR spectroscopy, FTIR spectroscopy, X-ray diffraction (XRD), UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS) and dye adsorption techniques.
(iii) A CV study that employs modified PANI-based electrode materials (Ag@CHI-PANI and Ag@P-CA) for electrochemical characterization of properties and nitrophenol detection.
The long-term objective of this thesis is to develop novel modified PANI-based electrode materials for the electrochemical detection of 2-NP in water and environmental groundwater samples. Based on the 2-NP adsorption isotherms, Ag@CP75 was effective as an electrode material with 40% and 330% higher 2-NP adsorption capacity than PANI and CHI, respectively. Based on the CV of modified PANI-based composites in nitrophenol solutions, the relative standard deviation (RSD) of 5.70% was assigned to Ag@CP75's selectivity in the presence of nitrophenol isomers and inorganic salts. The RSD’s of 2.68% and 2.64% were accredited to Ag@CP75's stability (nine cycles) and reproducibility (ten cycles) for the electrochemical detection of 2-NP, respectively. CV studies on Ag@P-CA supported the increase in electron transfer rate after the deposition of Ag NPs onto P-CA. Lastly, an illustration of the pathway for the detection of nitrophenols with PANI-modified electrode materials was proposed based on the electrochemical results obtained in this thesis and the theory of electrochemistry (cf. Figure 5-11). This illustrated pathway divides 2-NP detection mechanism into various steps (chemical reaction, adsorption, desorption, electrochemical reaction). By optimizing each of these steps, the detection mechanism can be improved for future studies
Non-Isolated On-Board Charger for E-Mobility Vehicles with Minimal Common-Mode Current
No full textTo combat climage change and reduce emissions caused by the transportation sector, electric vehicles have emerged as a cleaner and more efficient alternative to the internal combustion engine. On-board chargers take the supplied AC, coming from the power grid, and converting it to DC which then is used to charge the traction battery of the vehicle. In order to widen the acceptance of electric vehicles, lower charging times and therefore higher power transfers are necessary. As space is limited in electric vehicles, an increase in power density for on-board chargers is crucial to achieve this goal.
Most state-of-the-art on-board chargers employ a two-stage, isolated design. A non-isolated designs promise a higher power density by omitting bulky inductive elements such as the high-frequency transformer. This work presents a single-stage, non-isolated design, which can be operated in three-, two- or single-phase mode. A non-isolated design poses challenges in regard to common-mode issues, which may trip the residual current device in the wall box, as well as the absence of a transformer limiting the lower-end traction battery voltage, making this design only feasible for 800 V systems.
All aspects of the charger, starting from the modulation schemes, DC-link and filter dimensioning, operation with less than three phases, or control implementation are thoroughly investigated. A two- or single-phase mode is proposed and investigated to solve the lower-end battery voltage issue. Common-mode generation mechanisms are identified, a theoretical model is designed and simulated. A hardware prototype is designed and presented, and used to verify the theoretical model and simulations with real-world measurements.
Efficiency measurements show the benefit of a solely single-stage design, but current constraints given by the electric vehicle manufacturers, mainly common-mode capacitance as well as battery voltage range, make a purely single-stage solution not feasible. Common-mode capacitance measurements on electric vehicles show a wide range of values, making the design of single-stage topologies difficult. The conclusion shows an alternative two-stage non-isolated topology, which might be able to solve any common-mode issues left
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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