1,720,956 research outputs found
Internal surface roughness measurement of metal additively manufactured samples via x-ray CT: the influence of surrounding material thickness
No full textX-ray computed tomography (XCT) can be used to measure the internal and external surfaces of an object non-destructively and with micron-level spatial resolution. XCT is therefore an appealing method for measuring and characterising the internal surface roughness of additively manufactured parts that cannot be accessed by traditional tactile and optical surface roughness instruments. In this work, an additively manufactured aluminium spherical surface roughness sample is designed, fabricated and its surface roughness measured via a focus variation microscope, the sample is then XCT scanned when embedded in varying thicknesses of surrounding material. A quantitative and qualitative comparison between the optical and XCT surface roughness measurements is made; the results show that the Sa of the XCT-based surface roughness measurements increases as a function of surrounding material thickness
Beam filtering in industrial X-ray computed tomography
No full textX-ray CT is considered as the future of non-destructive evaluation and metrology scanning device. The emergence of industry 4.0 sees a rising adoption of additive manufacturing application in the manufacturing industry and hence a higher utilisation demand for X-ray CT. Industrial X-ray CT is a polychromatic source that releases X-ray energy in different energies and it is usually dominated with low energy X-rays. Due to the underlying physical constrain surrounding X-ray physics, a physical filter are often needed to remove the low energy X-rays. A proper filtering will remove image artefacts due to low energy X-ray presence. Despite this, it is known that there is insufficient methodology for a proper X-ray filtering for an X-ray operator to adhere to. An operator typically relies on operating experience to judge on the material type and thickness of the filter. This means that the decision may differ from one operator to another. This different methodologies from one operator to another can lead to different image quality and a non-standardisation of the result. When the X-ray CT is used by the operator for measurement purposes, the steps taken has to be traceable and standardised. In this project, a review of literature landscape on theoretical quantification of image quality based on filtering decision is done and the theories are then compiled in an excel database to be used as an optimisation method. The theoretical simulation were then verified with real experimental data to verify the correlation between the data and theoretical simulation. The result shows a significant correlation between the simulation and multiple experimentation data between different machines. This means that the simulation software developed in this project can be used as a benchmark for a standardised filter choosing methodology which was then implemented as a standard operation procedure in Advanced Remanufacturing and Technology Centre (ARTC).Bachelor of Engineering (Mechanical Engineering
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
Inducing a Realistic Surface Roughness onto 3D Mesh Data Using Conditional Generative Adversarial Network (cGAN)
No full textIn the age of machine learning, data-driven approaches with hybrid data (a mixture of real images and simulation images) are getting increasingly popular. One major issue with creating a realistic simulation for surface engineering is that the surface of the mesh model used in the simulation is smooth. Often, this mesh does not contain information on surface texture; thus, simulating an object based on these meshes may not represent an actual surface texture of a real component. This article presents a novel technique for introducing surface roughness onto a smooth mesh object to facilitate engineering simulation by using a conditional Generative-Adversarial Network (cGAN) that is trained on real height maps to generate random 2D height maps that represents a realistic texture of a typical upskin and downskin surface of an additively manufactured (AM) part. This approach extracted the past scans of AM components from the Focus Variation microscopy. The 3D surface deviation is extracted as height maps and used as the training data for the generative network. This paper will also discuss the structural similarities between the synthetic and real data using standard descriptors for surface texture characterisation, such as Sa, Sq and Sdq.</p
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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