1,720,975 research outputs found
Dataset in support of the article 'Large-scale density functional theory simulations of defects and hydrogen incorporation in PuO2'
No full textThis dataset hosts computational data supporting the findings in the paper: Large-scale density functional theory simulations of defects and hydrogen incorporation in PuO2, Nabeel Anwar, Robert M. Harker, Mark T. Storr, Marco Molinari, and Chris-Kriton Skylaris, Phys. Rev. B, 2024, 109, 224102. Available from https://doi.org/10.1103/PhysRevB.109.224102.
The data is located at: Anwar, Nabeel (2024), “Data for: Large-Scale DFT Simulations of Defects and Hydrogen Incorporation in PuO2”, Mendeley Data, V1, doi: 10.17632/7v6gc7bz34.1
Accessible under UK Ministry of Defence © Crown owned copyright 2024/AWE
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Data for Chapter 4 (Properties of and Charged Defects in ThO2) of the PhD Thesis - Large-Scale Density Functional Theory (DFT) Simulations of Lanthanide and Actinide Oxide Materials
No full textThis dataset contains the computational data supporting the findings in Chapter 4 (Properties and Charged Defects) of the PhD thesis: Large-Scale Density Functional Theory (DFT) Simulations of Lanthanide and Actinide Oxide Materials in ThO2 by Nabeel Anwar. Supervised by Robert M. Harker, Mark T. Storr, Marco Molinari and Chris-Kriton Skylaris.
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Large-scale density functional theory simulations of defects and hydrogen incorporation in PuO2
Get PDFWe have examined a range of point defects, Frenkel pairs, Schottky defects, and hydrogen-related defects in the PuO2 system (supercells of 96 and 768 atoms) using the onetep linear-scaling density functional theory code. Vacancy point defects related to oxygen are found to be more stable than those related to plutonium. The oxygen in the octahedral interstitial is higher in the formation energy than the plutonium in the same octahedral site, although the difference is less than 1 eV. We were also able to identify a stable peroxide species (1.57–2.67 eV) with a O-O distance of 1.46 Å. Of the Frenkel defects we studied, we found that the oxygen is more stable than the plutonium, whereas the Schottky stability changes as a function of supercell size. Finally, we examined a number of likely hydrogen sites in the PuO2 lattice: octahedral interstitial, oxygen edge, hydroxyl, oxygen vacancy, and plutonium vacancy. We report hydrogen which exists as a hydride at oxygen and plutonium vacancies to be relatively high in energy (2.69–3.81 and 13.71–15.54 eV, respectively). The hydrogen was found to exist as a radical at the octahedral interstitial site (2.43–3.38 eV) and which is somewhat higher formation energy than other studies find. We find that the hydrogen at the oxygen edge (as a H+ cation) and at the oxygen cube corner (as a hydroxyl) are both lower in energy (1.14–1.40 and 1.17–1.56 eV, respectively) as opposed to hydrogen in the octahedral interstitial site but again higher than found by other studies. We discuss the data in the context of potential hydrogen transport pathways and how that might be modified by radiation damag
Using molecular dynamics to simulate realistic structures of nitrocellulose of different nitration levels
No full textNitrocellulose is a reactive derivative of cellulose, one of the most commonly occurring natural materials. Nitration of cellulose decreases the stability of the structure, meaning less is understood about its structure and reactions. Although cellulose is often found in fully crystalline forms, nitrocellulose is more commonly paracrystalline, or amorphous. We present a protocol based on molecular dynamics simulations for creating realistic structures of nitrocellulose, particularly focusing on the crystallinity of the systems being created. We will also provide a detailed analysis of the geometric and dynamical parameters used to quantify the degree of crystallinity for the structures created here, with nitration levels varying from 0-14.14 wt% nitrogen content. Paracrystalline cellulose was not created using the protocol designed here, although it was found that the more nitrated a nitrocellulose system, the more the structure tends to paracrystallinity. This is due to a decrease in the number of hydrogen bonds present, and an increase in the size of the functional groups pushing the chains apart and weakening the interactions between the chains of the structure. The structures created are representative of realistic systems, which in the future will be able to be used to build further understanding of long-term storage of nitrocellulose.</p
Dataset in support of the article 'Linear-scaling density functional theory (DFT) simulations of Point, Frenkel and Schottky defects in CeO2'
No full textThis repository hosts computational data supporting the findings in the open-access paper: Linear-Scaling Density Functional Theory (DFT) Simulations of Point, Frenkel and Schottky Defects in CeO2, Nabeel Anwar, Robert M. Harker, Mark T. Storr, Marco Molinari and Chris-Kriton Skylaris, Comp. Mater. Sci., 2023, 229, 112396. Available from https://doi.org/10.1016/j.commatsci.2023.112396.</span
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
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