1,720,955 research outputs found
Metal Powder Benchmarking
No full textMetal additive manufacturing technologies are widely employed in the aerospace, automotive and medical industries. Selective laser melting is a type of metal additive manufacturing process in which powders are consolidated layer by layer in a predefined pattern with the help of a laser beam to create a component. Powder characteristics are critical in influencing the quality of the printed component. Metal powders must be within a specific size range and have spherical morphology to exhibit good flow and spread behaviour during the additive manufacturing process. It is necessary to understand the flow behaviour to comprehend the powder’s performance during the process. The study investigates the effect of powder characteristics like particle shape, particle size and size distribution on the flow behaviour of steel powders. Powder characterisation techniques relevant to the powders for additive manufacturing application is identified and performed. Sieve analysis fails to incorporate the particle shape during the particle size estimation. Optical microscopy is not a robust method for determining the particle shape. Flow behaviour of the powders was studied using flowmeter test, rheometric analysis and static angle of repose test. Rheometric analysis is more sensitive to minor variations in the flow behaviour compared to flowmeter tests. The static angle of repose test fails to incorporate the stresses experienced by the powder during the process and can be used to get a rough estimate for the powder flow behaviour in terms of cohesion. Of the seven steel powders examined, the same powder with flow time 12 [s/(50 g)] kept being ranked in the top three for all the flow tests. So this powder is recommended for use in additive manufacturing. In addition, one other powder that failed in flowmetertests was consistently placed towards the bottom of all tests.Metalladditiv tillverkningsteknik används i stor utsträckning inom flyg, fordons, och medicinsk industri. Selektiv lasersmältning är en typ av metalladditiv tillverknings process där pulver konsolideras lager för lager i ett fördefinierat mönster med hjälp av en laserstråle för att skapa en komponent. Pulveregenskaper är avgörande för att påverka kvaliteten på den tryckta komponenten. Metallpulver måste ligga inom ett visst storleksintervall och ha en sfärisk morfologi för att uppvisa ett bra flödes, och dispersionsbeteende under den additiva tillverkningsprocessen. Det är nödvändigt att förstå flödesbeteendet för att förstå pulvrets prestanda under processen. Studien undersöker effekten av pulveregenskaper som partikelform, partikelstorlek och storleksfördelning på flödesbeteendet hos stålpulver. Pulverkarakteriseringstekniker som är relevanta för pulvren för tillsatstillverkning identifieras och utförs. Siktanalysen misslyckas med att införliva partikelformen under partikelstorleksupp skattningen. Optisk mikroskopi är inte en robust metod för att bestämma partikelformen. Pulvrets flödesbeteende studerades med hjälp av flödesmätartest, reometrisk analys och statisk vinkel på vilotest. Reometrisk analys är mer känslig för mindre variationer i flödesbeteendet jämfört med flödesmätartester. Det statiska vilovinkeltestet misslyckas med att införliva de påfrestningar som pulvret upplever under processen och kan användas för att få en grov uppskattning av pulverflödesbeteendet i termer av kohesion. Av de sju stålpulver som undersöktes rankades samma pulver med flödestiden 12 [s/(50 g)] i topp tre för alla flödestester. Så detta pulver rekommenderas för användning i additiv tillverkning. Dessutom placerades ett annat pulver som misslyckades i flödesmätartester konsekvent mot botten av alla tester
Development of sustainable Aluminium alloy powders for metal additive manufacturing
No full textPòster amb el resum gràfic de la tesi doctoral en curs, que forma part de l'exposició "Doctorat en Recursos Naturals i Medi Ambient de la UPC Manresa. 30 anys formant en recerca a la Catalunya Central 1992-2022".This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101034328.Postprint (published version
Development of sustainable Aluminium alloy powders for metal additive manufacturing
Get PDFPòster amb el resum gràfic de la tesi doctoral en curs, que forma part de l'exposició "Doctorat en Recursos Naturals i Medi Ambient de la UPC Manresa. 30 anys formant en recerca a la Catalunya Central 1992-2022".This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 101034328.Postprint (published version
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
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