1,720,981 research outputs found
Enhancing the durability of hydrocarbon-membrane-based polymer electrolyte water electrolysis using a radical scavenger-embedded interlocking interfacial layer
No full textHydrocarbon membranes are an attractive alternative to Nafion membranes for use in proton exchange membrane water electrolysis (PEMWE) due to their low gas permeability and high proton conductivity. However, hydrocarbon membranes and Nafion-based catalyst layers are prone to delamination, not allowing long-term operation of hydrocarbon-membrane-based PEMWE. In the present study, we propose a radical-scavenger-embedded interlocking interfacial layer (IIL) that addresses this interfacial delamination issue. The ball-socket joint structure of the IIL leads to mechanical interlocking at the interface, and the presence of cerium oxide as a radical scavenger prevents the hydrothermal degradation of the IIL. Cerium oxide-containing IIL-based PEMWE subsequently operates for more than 500 h with lower polarization at a voltage increase rate of 48 mu V h(-1), which is much lower than that of state-of-the-art hydrocarbon-based PEMWE and is even lower than that of Nafion-based PEMWE (53 mu V h(-1)). The long-term durability of a hydrocarbon-membrane-based PEMWE system, reported for the first time in the present study, represents an important milestone for the development of cost-effective PEMWE systems.
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
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
A Study on Corrosion Behaviors of Ferritic/Martensitic Steels in Liquid Sodium Condition for Sodium-cooled Fast Reactor Application
No full textDepartment of Nuclear EngineeringResearch purpose is the study on corrosion of Gr. 92 steel (ferritic/martensitic steel) with liquid sodium for advanced nuclear reactors application. Moreover, development of new measurement methods of oxygen and carbon dissolved in sodium has been carried in this study.
In this study, ASTM A182 Grade 92 steel was exposed to liquid sodium at 650??C in order to investigate surface oxidation and corrosion behavior as well as microstructure changes, especially production of precipitates. Comparisons were made to the same material exposed to argon gas at 650??C. In sodium-exposed specimens, intergranular oxidation and chromium depletion were observed at the near surface by an electron probe micro analyzer (EPMA) used for elemental analysis. The chromium, oxygen, and sodium X-ray images overlapped, indicating NaCrO2 oxidation. Since, the carbon image overlapped on NaCrO2 oxide, the carbon was trapped in the oxide. The chromium image shows the chromium-depleted zone. With the argon-exposed specimen, however, this behavior at the surface was not observed. Different types of precipitates in the Gr.92 steel matrix were observed. At the interface between the Cr-depleted zone and the bulk steel matrix in specimens exposed to 650??C liquid sodium showed mainly M23C6 carbide, while specimens in the bulk steel matrixes which exposed to 650??C sodium as well as argon showed mainly a M2(W,Mo) phase. These differences may be mainly a result of oxidation (NaCrO2) and chromium depletion, and presumably decarburization observed in the sodium-exposed specimens, which are different from the precipitate behavior in the case of the bulk steel matrix in sodium as well as argon-exposed specimens.
Non-metallic elements, such as carbon, oxygen, and nitrogen in sodium have a large effect on the mechanical behavior and corrosion rates of materials in the primary and secondary coolant heat transport system in sodium-cooled fast reactors (SFRs). Austenitic Fe-18%Cr-8%Ni foil and ferritic Fe foil were equilibrated at 550??C sodium. After the equilibration, the concentration of carbon in the foils was analyzed by carbon analyzer (Leco). The carbon activity in liquid sodium was calculated. Also the thermodynamic activity of carbon in ferrite iron (Fe-C alloy) were calculated in the temperature range of 682 - 848??C. An equilibrium method using ferrite iron steel has been developed to measure the activity of carbon in liquid sodium. The results obtained are discussed and a new expression is proposed relating carbon activity with the composition of steel. The thermodynamics of carbide equilibrium in the steel are discussed by characterizing the carbide phase. These data have been analyzed using regular solution model for the carbide phase, Fe3C and based on this observed composition of Fe3C as well as the variation of the carbon potential of steel with temperature have been explained.ope
Corrosion Behaviors of Structural Materials in Liquid Gallium and Gallium Alloy Environments for Nuclear Application
No full textInterdisciplinary School of Green EnergyLiquid Metal Fast Breeder Reactor (LMFBR) is one of promising candidates among Gen IV nuclear energy systems. Among liquid metal, sodium is a spotlighted coolant material for designing fast breeder reactor. However, high activity of sodium with water and air is the major disadvantage that forces to search for alternatives. On the other aspects, the liquid metal including gallium generally interacts with structural materials, and it may cause Liquid-Metal-Embrittlement (LME) to materials in certain condition.
The purpose of this work is to examine the interaction between steels and liquid gallium or gallium alloys to evaluate the potential application of gallium for fast reactor coolants. In fact, gallium could be a good candidate for use as a liquid metal in the field of GEN IV nuclear system since it has low melting point (29??C), high boiling point (2204??C) and high safety against explosion. However, gallium has a high affinity for many metals and alloys, especially steels. For the prevention of liquid gallium corrosion with stainless steels, an active control of oxygen partial pressure which has been extensively studied for lead-bismuth corrosion could be adopted in this gallium environment.
The liquidus of gallium alloy (Ga-14Sn-6Zn and Ga-8Sn-6Zn) is 26??C and 19.5??C, respectively. Simultaneously, neutron absorption cross-section is reduced by these alloy process.
In this study, SS 316L and pre-oxidized specimens were exposed to static gallium and gallium alloys (Ga-14Sn-6zn and Ga-8Sn-6Zn) at 500??C for time up to 700 hr both in air and vacuum conditions (5x10-6 torr). The results have shown that the corrosion resistance of pre-oxidized specimens was improved compared to bare specimens in metal loss data. The weight change and metal loss were generally reduced in vacuum condition and also in gallium alloy environments. General behavior of developing reaction layer within the effect of pre-oxidation was that pre-oxidized specimens, in any conditions, had developed as thick as reaction layers on bare specimens.ope
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