1,722,693 research outputs found
Field-driven multi-variable framework for tailoring of additively manufactured lattice-infilled wing structures
No full textLightweight components are in high demand in aerospace due to their environmental and economic benefits. Reducing aircraft weight can significantly lower carbon emissions and environmental impact. Advances in additive manufacturing have enabled the production of intricate lattice structures, opening new possibilities for aerospace applications. Lattice-infilled structures are a research hotspot for weight reduction without compromising structural integrity. Selecting lattice parameters such as unit cell type, size, and thickness is challenging with manual methods. Therefore, this study developed a comprehensive lattice design framework using the commercial modeling tool nTop and performed a numerical analysis of lattice-infilled UAV wings in ANSYS workbench. Unit cell type, size, and thickness variations were analyzed based on applied loading conditions through iterative simulations with Python coding. Five-unit cells (BCC, FCC, Kelvin, Fluorite, and Octet) were used in a UAV wing example, arranged in different configurations from uniform distribution to gradient lattice structures tailored by design data fields. Iterative simulations identified the optimal unit cell type, size, and thickness under level flight loading conditions. The results showed significant weight reduction with enhanced stiffness and stress distribution compared to conventional wing structures. Among the five-unit cells, the Octet performed best, and configuration 4 excelled in performance due to its lightweight and improved properties. This study provides an automatic lattice selection process with variable parameters for lightweight lattice-infilled design, guiding design engineers in selecting appropriate unit cells and parameters for specific requirements
Innovative Hybrid Lattice Infilled Wing Design with Additive Manufacturing
No full textLightweight structures with a high stiffness-to-weight ratio are crucial for reducing aerospace weight. Lattice infilled structures have proven superior to conventional ones, offering better stiffness, strength, and lower weight. Additive manufacturing (AM) enables the production of these complex lattice structures, overcoming traditional manufacturing challenges. Composite materials, known for their exceptional properties, especially in different environmental and flight conditions, are increasingly replacing metallic parts. Combining metallic lattice structures with composite skins offers an optimal solution for aircraft wing design, improving performance and reducing weight. This study assesses the feasibility of metallic and hybrid (metal-composite) lattice infilled wing for a drone compared to traditional spar-rib design using finite element analysis. A comprehensive design framework for AM was developed using nTop tool. Iterative simulations were conducted to find the optimal type and size of lattice unit cells under level flight loading conditions. The process involved Python coding for iterative simulations, resulting in significant weight reduction, lower stress, and reduced wing tip deflection for lattice structures. A comparative study also examined the replacement of metallic skins with composite skins for further weight reduction and enhanced performance. The findings highlight the potential of innovative lightweight hybrid wing designs for aerospace applications
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
Moyamoya angiopathy in Europe: the beginnings in Zurich, practical lessons learned, increasing awareness and future perspectives
No full textThe number of patients, especially children, diagnosed with Moyamoya angiopathy and being referred to us for treatment from all across Europe, has increased over the last few years. An increase in awareness of the occurrence of stroke in children in the general and medical population might be the main cause of this phenomenon. Increasing awareness does not happen "spontaneously" nor does it manifest overnight! It requires regular platforms of communication between the general population and amongst the different medical specialists mainly neurologists, paediatric neurologists, neuropsychologists, neuroradiologists, neurorehabilitation specialists, nursing staff and neurosurgeons. Presently we were lucky to conduct the first Moyamoya Symposium ever to be conducted at a European-Japanese level with participation of specialists of this particular field from across Europe and Japan. Ever since the first child with Moyamoya was managed at the University hospital in Zurich some 7 years ago the number of patients referred to us from all across Europe increased rapidly. The importance of interdisciplinary communication, trust and support amongst specialists and increasing the awareness of the disease among the patients, medical personnel was and remains to be just as important as making the correct diagnosis and treatment of choice in these patients. We present the lessons we learned during these previous years and look into the future perspectives that require our further and urgent attention
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
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
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