1,720,961 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
Synthesis of three dimensional graphene for sorption of oils and organic solvents
No full textOil spill accidents release large amount of oil and organic liquids in the sea every year. This not only results in huge economic loss but also causes environmental pollution and ecological problems. Conventional mechanical methods of oil recovery need large amount of labor and equipment making the process very costly. Therefore, new oil remediation ways need to be developed. One such method which is attractive due to its low cost is the use of porous materials that can adsorb the oil. Many porous adsorbents are there in the market that include natural and synthetic inorganic and organic materials such as cotton, wool, zeolites, graphite, activated carbon and conjugated microporous polymers but these conventional material have various issues such as low adsorption capacity, high cost and complex synthesis methods. Graphene which is discovered recently in 2004 has been used in various applications such as composites, supercapacitors, electronics and sensors. However 2D graphene cannot be used for oil adsorption on large scale as its only one atomic layer thin. Graphene based three dimensional structures can be used for this purpose due to their high surface area and hydrophobic surface. In this work, 3D graphene is synthesized in two steps. First, graphene oxide solution is synthesized by oxidation of graphite precursor using modified hummers method. Afterwards, graphene hydrogel is formed by hydrothermal treatement of graphene oxide and freeze drying is done to obtain final dry graphene aerogel. Synthesized material is characterized using various morphological and chemical characterization techniques. SEM and nitrogen adsorption desorption tests shows that material has pores of various sizes and shapes made of interconnected graphene sheets. Oil adsorption experiments revealed that this materials can adsorb (40-70 g/g) of various oils and organic solvents which is higher than commercial sorbents. Adsorption rate is studied as most oil spreading occurs within first few hours of oil spill. This kinetic study shows very fast uptake of oils and organic solvents. Adsorbate can be removed from graphene aerogel by heating for several cycles without much change in adsorption capacity of material. These results of high adsorption capacity, fast rate of adsorption and reusability suggest that graphene based 3D material can be promising material for oil spill cleanup than commercial sorbents.</p
Metal-carbon nanocomposites for electrochemical sensing of hydrogen peroxide (H2O2)
No full textDetection of H2O2 is required in many fields as it is widely used as an oxidizer, bleaching agent, and disinfectant. Electrochemical sensors are a promising choice among various detection technologies in which electrocatalyst design has a significant impact on sensor performance. Metal nanoparticles (NPs) are commonly used for electrochemical detection of target analytes, but they undergo aggregation, hindering their full utilization. Porous nanocarbons have emerged as promising conductive support materials to disperse metal NPs and increase electrocatalyst utilization efficiency. In this PhD work, novel electrocatalysts of metal-carbon nanocomposites were synthesized with the goal to achieve higher sensitivity, wide detection range and lower detection limit in H2O2 sensing. In the first project, ultralow mass loading of Pt NPs on a porous carbon nanocomposite comprised of reduced graphene oxide and carbon nanotubes was achieved by cathodic polarization treatment. Electrochemical amperometic tests reveal its superior H2O2 sensing performance with a low detection limit of 1 μM and wide linear detection range up to 15 Mm whereas sensitivity of 2027 μA/ mM·cm2 is the best among recently reported Pt/carbon composite based H2O2 sensors. It can also detect H2O2 in milk and juice samples below the FDA permitted residual H2O2 level in food packaging. In the second project, non-precious metal cobalt/carbon nanocomposite electrocatalyst was explored for efficient H2O2 sensing on multiple sensor platforms, synthesized by carbonation of electrospun polyacrylonitrile nanofibers containing zeolitic imidazole framework (i.e., ZIF-67) particles. Apart from detection on conventional glassy carbon electrodes (GCEs), electrocatalyst has sufficient mechanical strength as a self-standing film providing linear detection range upto 50 mM. Further, it enables mobile H2O2 detection on screen-printed electrodes (SPEs) when integrated with a portable potentiostat and mobile phone
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
Synthesis of Graphene Based Three Dimensional Structures for Highly Efficient and Recyclable Adsorption of Oils and Organic Solvents
No full textkoamabayili/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
- …
