1,720,966 research outputs found
Advances in the application of the Principal Static Wind Loads: A large-span roof case
No full textIn this paper, a procedure to define a small set Multi-target Equivalent Static Wind Loads (M-ESWLs) that allows for the verification of a large set of structural elements of a stadium roof is presented and applied to a real case. The methodology, based on the combination of the so-called Principal Static Wind Loads (PSWLs), is aimed at reducing the subjectivity of the designer in the identification of the most challenging structural conditions induced by wind actions, and therefore it allows to simplify and speed up the wind-resistant design process of roof structures.Starting from wind tunnel tests on a scaled rigid model of a stadium, the dynamic response of its roof is computed by loading the finite element model of the structure with the time histories of the spatially averaged net pressures acting on its surface. The time histories of the internal forces acting in a set of structural members are reconstructed, and the target envelope is built by identifying, for each of them, a maximum and a minimum value through a statistical analysis of the time series. For each of these extreme conditions an ESWL is identified, PSWLs are computed and combined by means of a genetic algorithm, and the set of M-ESWLs, able to match the envelope, is defined. To limit the number of M-ESWLs, a nonlinear constrained optimization is implemented in the PSWLs combination, also introducing the possibility to over-dimension some structural members.It is concluded that the application of this methodology allows the designer to select a limited number of M-ESWLs that can be used in an automated way in order to verify the response of a defined set of structural elements
Key parameters influencing wind-induced aeroelastic responses of single-axis solar trackers in photovoltaic plants
Full text linkSingle-axis solar trackers enhance energy production and cost-effectiveness in large-scale solar installations compared to fixed panels. However, their structural design must address unique challenges, particularly regarding wind resistance, due to reduced mechanical properties for cost savings. This article examines several key parameters of solar plants and evaluates their influence on tracker response, emphasizing wind-induced aeroelastic effects. These parameters include the layout arrangement of solar plants and the inter-row spacing. Tracker position has been evaluated in a 4-rows by 2-column corner region of rectangular tracker plant, with two ground cover ratios of 0.38 and 0.25. Moreover, the effects of the operational parameters of individual trackers have also been monitored, considering working pitch angles in the range between −60∘ and +60∘ and wind exposure angles of 0°, 15°, 30° and 45°. Structural properties were assumed to remain constant. The research combines experimental wind tunnel tests with numerical dynamic simulations based on a finite element model, monitoring the internal stress state to assess performance. Results show that large pitch angles (>45∘) exhibit stable aeroelastic behavior, while small pitch angles, between −30∘ and +30∘, become unstable after reaching a certain velocity threshold. Among the monitored pitches, inclinations between 15° and 30° are the most critical in terms of internal response. The research confirms that trackers on the perimeter are the most stressed in the plants. The largest load cases occur with wind directions normal to the tracker axis. Finally, the analysis of the spacing between rows showed no significant effect on the response
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
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
Valutazione clinica dei sintomi positivi e negativi riscontrati negli schizofrenici tuttora istituzionalizzati nell'ex ospedale psichiatrico di Bologna
No full textkoamabayili/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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