1,720,962 research outputs found
Atomistic modelling of Fe-Al and α-AlFeSi intermetallic compound interfaces
Full text linkThe joining of aluminum and steel has been considered an efficient solution for building light-weight technology, particularly in the automotive, aerospace and shipbuilding industries. It is an immense challenge to join these materials together due to the significant differences in the physical and chemical properties of aluminum and steel. The development of intermetallic compound (IMC) layers has a huge impact on the strength of the aluminum-steel joint. The development of IMCs at the aluminum and steel joint is greatly influenced by the welding methodology and temperature reached during the welding process. It is thermodynamically possible to develop certain IMCs depending on the composition and phase diagram of aluminum and steel alloys. For this reason, understanding the mechanical nature of the IMCs is pivotal to improve the welding methodologies.
In this work, atomistic simulations were performed on Fe2Al5, Fe4Al13 and α-AlFeSi bulk and interface structures. We started with the construction of atomistic bulk structures of Fe2Al5 and Fe4Al13 and calculated the mechanical properties using density functional theory (DFT) calculations. A comparative study was performed to identify the mechanical behavior of these compounds. Moreover, comparisons were also made with other experimental, semi-empirical and ab-initio methods to test the reliability of the calculations.
Due to the complex nature and large atomic structures of Fe-Al IMCs, using ab-initio methods could be very computationally expensive. To make computational calculations fast and accurate, a semi-empirical potential based method has also been used in this work. The main objective of this study was to test the reliability of modified embedded atoms method (MEAM) potentials and suitability for finding good initial structures for Fe-Al interfaces. It was concluded that MEAM and semi-empirical methods are not reliable for inferring mechanical features of Fe-Al IMCs. However, MEAM was found to be reasonable for finding good initial guesses for the Fe-Al interface structures.
Lastly, a systematic study was performed to identify the virtual tensile and shear strengths of Fe-Al and α-AlFeSi interfaces using DFT. Interface structures were optimized using the fast inertial relaxation engine (FIRE), which was very successful in optimizing these complex interfaces with a large number of atoms. After the optimization of the interface structures, virtual tensile and shear strength calculations were performed. An extended version of the so-called Universal Binding Energy relation (UBER) was used to fit the energy-displacement curve for virtual tensile strength and a Fourier series for the virtual shear strength predictions. The results indicated the potential negative effect of the Fe-Al IMCs on the strengths of the aluminum-steel joint
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
Atomistic modelling of Fe-Al and α-AlFeSi intermetallic compound interfaces
No full textThe joining of aluminum and steel has been considered an efficient solution for building light-weight technology, particularly in the automotive, aerospace and shipbuilding industries. It is an immense challenge to join these materials together due to the significant differences in the physical and chemical properties of aluminum and steel. The development of intermetallic compound (IMC) layers has a huge impact on the strength of the aluminum-steel joint. The development of IMCs at the aluminum and steel joint is greatly influenced by the welding methodology and temperature reached during the welding process. It is thermodynamically possible to develop certain IMCs depending on the composition and phase diagram of aluminum and steel alloys. For this reason, understanding the mechanical nature of the IMCs is pivotal to improve the welding methodologies.
In this work, atomistic simulations were performed on Fe2Al5, Fe4Al13 and α-AlFeSi bulk and interface structures. We started with the construction of atomistic bulk structures of Fe2Al5 and Fe4Al13 and calculated the mechanical properties using density functional theory (DFT) calculations. A comparative study was performed to identify the mechanical behavior of these compounds. Moreover, comparisons were also made with other experimental, semi-empirical and ab-initio methods to test the reliability of the calculations.
Due to the complex nature and large atomic structures of Fe-Al IMCs, using ab-initio methods could be very computationally expensive. To make computational calculations fast and accurate, a semi-empirical potential based method has also been used in this work. The main objective of this study was to test the reliability of modified embedded atoms method (MEAM) potentials and suitability for finding good initial structures for Fe-Al interfaces. It was concluded that MEAM and semi-empirical methods are not reliable for inferring mechanical features of Fe-Al IMCs. However, MEAM was found to be reasonable for finding good initial guesses for the Fe-Al interface structures.
Lastly, a systematic study was performed to identify the virtual tensile and shear strengths of Fe-Al and α-AlFeSi interfaces using DFT. Interface structures were optimized using the fast inertial relaxation engine (FIRE), which was very successful in optimizing these complex interfaces with a large number of atoms. After the optimization of the interface structures, virtual tensile and shear strength calculations were performed. An extended version of the so-called Universal Binding Energy relation (UBER) was used to fit the energy-displacement curve for virtual tensile strength and a Fourier series for the virtual shear strength predictions. The results indicated the potential negative effect of the Fe-Al IMCs on the strengths of the aluminum-steel joint
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
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
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