1,720,956 research outputs found
Synthesis of polyaramids in γ-valerolactone-based organic electrolyte solutions
No full textsponsorship: This research was funded by a doctoral (PhD) strategic basic research grant of the Research Foundation Flanders (FWO) to Jonas Winters (1S12717N). The help of Jakob Busse in the design and building of the 3D-printed spinning setup is greatly acknowledged. (Research Foundation Flanders (FWO)|1S12717N)status: Publishe
Stepwise reaction and degradation in solution synthesis of Li6PS5Br from P4S10
No full textTransport is the only sector to have increased its CO2 emissions since 1990, and regular passenger cars make up the largest part of these transport emissions. Thus, a growing need for sustainable mobility is clear, leading to an expanding electric vehicle market. Lithium-ion batteries are considered most suitable for these vehicles owing to their large volumetric and gravimetric capacities. The need for increased battery performance as well as improved safety makes solid-state batteries the main contender for next-generation Lithium-ion batteries in all battery development roadmaps. Among solid-state electrolytes, sulfide-based materials such as LGPS (Li10GeP2S12), lithium thiophosphates (Li3PS4 and related compounds), and lithium argyrodite-type (generally Li6PS5X, X being Cl, Br, or I) materials are attracting much attention because of their high ionic conductivity, which is comparable in magnitude to that of known liquid electrolytes, potential for improved safety, and potential for more sustainable production.
Synthesis of both lithium thiophosphates and their derived products, lithium argyrodites, can be performed in several ways: solid-state methods offer proven ways to achieve these materials, although they come at significant cost in both reaction time as well as energy consumption. Solution-based methods have been shown to produce these materials with lower reaction times, requiring a smaller energy investment, and offering access to metastable phases. A solution-based route starting from the precursor P4S10 towards the final Li6PS5Br argyrodite-type product has been described in literature by Yubuchi et al., whereby P4S10 and Li2S are first reacted in a tetrahydrofuran (THF) solvent to form Li3PS4, followed by addition of Li2S and LiBr in ethanol to form the Li6PS5Br product in a mixed-solvent solution. This work examines the presence of intermediate compounds in the first step of this synthesis (performed in THF), and the formation of ethanolic degradation products over time in the second step of the synthesis (performed in the THF-ethanol mixed solvent system) by a combination of analytical techniques including MAS-31P-NMR, liquid 31P-NMR and ICP-OES.This project receives financial support from Flanders Innovation & Entrepreneurship (VLAIO) and Umicore as part of Baekeland-mandate HBC.2020.2822. Bjorn Joos receives financial support from FWO (G053519N)
Stepwise reaction and degradation in solution synthesis of Li6PS5Br from P4S10
No full textTransport is the only sector to have increased its CO2 emissions since 1990, and regular passenger cars make up the largest part of these transport emissions. Thus, a growing need for sustainable mobility is clear, leading to an expanding electric vehicle market. Lithium-ion batteries are considered most suitable for these vehicles owing to their large volumetric and gravimetric capacities. The need for increased battery performance as well as improved safety makes solid-state batteries the main contender for next-generation Lithium-ion batteries in all battery development roadmaps. Among solid-state electrolytes, sulfide-based materials such as LGPS (Li10GeP2S12), lithium thiophosphates (Li3PS4 and related compounds), and lithium argyrodite-type (generally Li6PS5X, X being Cl, Br, or I) materials are attracting much attention because of their high ionic conductivity, which is comparable in magnitude to that of known liquid electrolytes, potential for improved safety, and potential for more sustainable production.
Synthesis of both lithium thiophosphates and their derived products, lithium argyrodites, can be performed in several ways: solid-state methods offer proven ways to achieve these materials, although they come at significant cost in both reaction time as well as energy consumption. Solution-based methods have been shown to produce these materials with lower reaction times, requiring a smaller energy investment, and offering access to metastable phases. A solution-based route starting from the precursor P4S10 towards the final Li6PS5Br argyrodite-type product has been described in literature by Yubuchi et al., whereby P4S10 and Li2S are first reacted in a tetrahydrofuran (THF) solvent to form Li3PS4, followed by addition of Li2S and LiBr in ethanol to form the Li6PS5Br product in a mixed-solvent solution. This work examines the presence of intermediate compounds in the first step of this synthesis (performed in THF), and the formation of ethanolic degradation products over time in the second step of the synthesis (performed in the THF-ethanol mixed solvent system) by a combination of analytical techniques including MAS-31P-NMR, liquid 31P-NMR and ICP-OES.This project receives financial support from Flanders Innovation & Entrepreneurship (VLAIO) and Umicore as part of Baekeland-mandate HBC.2020.2822. Bjorn Joos receives financial support from FWO (G053519N)
Conventional and less conventional solution-based synthesis of battery materials: Cathodes, anodes and electrolytes
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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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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