1,721,449 research outputs found
Dataset in support of the thesis 'Advanced characterisation of battery cathode materials using X-rays'
No full textRaw data files for this thesis is split into three main folders for materials of lithium iron phosphate, lithium nickel manganese cobalt oxide and lithium nickel aluminium oxide.
Electrochemical data for rate capability studies and upper voltage limit cycling was conducted using Biologic 805 battery cycler. In situ and operando cycling was conducted using Biologic SP-150 which can be accessed using software "EC-Lab".
HERFD-XANES and XES data was conducted at Diamond Light Source on the I20-Scanning beam line. HERFD-XANES data can be accessed using the software "Athena" and the XES data can be accessed using Origin.
Diffraction data was conducted on two diffractomters of Rigaku SmartLab and Bruker D2 PHASER which can be accessed using crystaldiffract software and GSAS-II. </span
Advanced characterisation of next generation battery cathode materials using X-rays
No full textIn recent years, lithium-ion batteries have been the topic of focus in the automotive industry as an alternative source of power through electric vehicles. Research has focused on producing new cathode materials using a variety of transition metal oxides. However, we are still yet to understand their behaviour completely.The focus of this Thesis was to investigate the changes that occur within the high-nickel cathode materials Li(Ni0.8Mn0.1Co0.1)O2 (NMC 811) and Li(Ni0.8Co0.15Al0.05)2 (NCA). This was achieved by developing a newly designed in situ electrochemical battery cell which enabled the materials to undergo X-ray analysis during a series of charge and discharge cycles at a variety of conditions.High energy resolution fluorescence detection X-ray absorption near edge structure (HERFD-XANES) and X-ray emission spectroscopy (XES), were used to probe the oxidation state changes of nickel, manganese, and cobalt in NMC 811 and nickel oxidation state changes in NCA. From the changes documented in the HERFD-XANES studies, the oxidation state changes in high nickel cathode materials were quantified during a cell cycle. The oxidation state changes contained information on the behaviour of transition metal oxides during a charge and discharge cycle and provided a greater understanding of the reversibility of the electrochemically active nickel whilst charging to a variety of upper limit voltages. Features that were found from the quantification of HERFD-XANES was that the cobalt and manganese species within NMC 811 were more electrochemically active than previously reported. Within NCA, we report data on how a higher upper voltage limit can impact the reversibility of nickel species within the cathode materials during a first cycle despite reporting that the bulk of the material is reversible. In situ and operando studies using X-ray diffraction (XRD) was able to probe the phase changes that NMC 811 and NCA undergo during a cell cycle when cycling to a range of various upper voltage limits. From these studies, we were able to quantify the lattice parameter changes in real time to understand the bulk changes of the material using XRD. Alongside the HERFD-XANES data which worked to understand the atomic level changes in elements using HERFD-XANES. From the high speed 2D XRD we were able to document a new feature in NMC 811 and NCA where we can see the expansion and contraction of the c-axis during a cell cycle and relaxation which helps us understand the behaviour of Ni4+ at high voltages and how the formation of Ni2+ occurs from the reduction of unstable nickel species
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
