102,188 research outputs found
The effect of fatigue on the arrangement of hangers in tied arch bridges
No full textThe arrangement of the hangers in tied arch bridges is one of the key issues in optimizing the design of this typology of bridges. Bending moments in the arch and the tie and axial forces in the hangers are usually the parameters on which attention is focused. The hangers are particularly vulnerable to fatigue phenomena but the variation of axial forces in hangers is not deeply studied despite the fact that it is an important parameter in relation to the fatigue behaviour of the hangers. In this context, this paper mainly deals with the reduction of fatigue stressing in hangers of road arch bridges. The analysis is carried out by varying the vehicular load position along the deck; the assumed parameters are the maximum variation and the average variation of the hanger force. Various hanger arrangements are considered: vertical, fan and network arrangement with inclined hangers having multiple intersections. One of the main results is that, on the one hand, vertical and fan arrangements are better than network ones if the fatigue in the hangers is considered as the only parameter, and, on the other hand, network arrangements are globally the best if the bending moments in the arch and the tie and the absolute values of the axial forces in hangers are also considered. Therefore, the work also focuses on decreasing the fatigue stressing of vertical, fan and network arrangements without increasing the bending moments in the arch and the tie. The results suggest that a slight modification of the radial arrangement near the arch springing points, namely using steeper hangers, leads to a smaller force variation in the hangers without increasing the bending moments in the arch and the tie
Rubus aetnicus Cupani ex Weston and R. canescens DC. (Rosaceae): an analysis
No full textBeek (2016) argued that Rubus aetnicus Cupani ex Weston was the correct name of the taxon that was then called R. canescens DC., and which was previously known as R. tomentosus Borkh. Moreover, R. canescens was stated to be not identical with R. aetnicus, but rather a form of R. × collinus DC. Matzke-Hajek (2016) raised objections to both statements. Therefore, the aim of this study was to thoroughly analyse both names and support this analysis with field work at the type localities and by DNA data. Despite the correspondence at the investigated conservative DNA loci, the investigation showed that the two species are morphologically different and must be conceived as separate taxa. According to the rules of the ICN, R. aetnicus, as the earliest available legitimate name, must be accepted as the correct name for R. tomentosus auct. non Borkh. There is no reason not to use the name R. aetnicus, which has not been commonly used until now. It is unambiguous, while any other name could cause confusion if it would be conserved. Other scientific names clarified in this study are R. aetnaeus Tornab. (= R. ulmifolius Schott), R. aetnensis Tornab. (= R. aetnicus) and R. argenteus Gmel
X-shooter observations of QSO pairs
No full textObservations of quasar pairs represent a powerful tool in the study of the intergalactic medium, providing in particular information on the quasar radiative feedback not only along the line of sight, but also in the transverse direction. In this paper, we present the spectra of the four quasar pairs we observed so far with X-shooter, and we discuss two individual spectra affected by the presence of a close quasar in the foreground
The QUBRICS Survey
No full textFinding the brightest QSOs at high-z is important both for constraining cosmic evolution and fundamental physics. However, in the Southern Hemisphere, the number of bright QSOs is still relatively scarce. The advent of recent databases, including SkyMapper, Gaia, DESI, offers a golden opportunity to fill in this gap. The QUBRICS survey (QUasars as BRIght beacons for Cosmology in the Southern hemisphere) has been active since 2019, exploiting these databases through machine learning techniques (e.g. CCA, PRF, XGB) and so far over 400 new, bright (i 2.5) QSOs have been spectroscopically confirmed. In this poster we highlight some of the multiple scientific applications enabled by such a dataset like (i) improving the estimate of the luminosity function; (ii) analyzing absorption features along the line of sight and (iii) improving the performance of the selection algorithms. In the future, QSOs confirmed by this survey will be the targets of subsequent studies using higher resolution spectrographs like MIKE, ESPRESSO, WINERED and will be prime targets for foreground galaxy redshift surveys with LLAMAS
O Ser da técnica conforme Martin Heidegger e Jacques Ellul
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em FilosofiaMartin Heidegger e Jacques Ellul sao geralmente considerados como pensadores que entenderam a tecnica moderna como uma entidade autonoma com relacao a vida humana, por mais que o homem seja o criador das tecnicas e artefatos. Heidegger parece ver na tecnica moderna uma sorte de destino a que o homem nao pode escapar. Ellul denuncia o #\fenomeno tecnico. como uma realidade que, uma vez instalada, escapa ao controle humano. Este trabalho analisa as ideias de ambos os pensadores e mostra que, no entanto, nao e facil atribuir a nenhum deles a crenca num determinismo tecnologico. Esperamos assim contribuir, nao apenas para a melhor compreensao desses autores, como tambem para saber ate que ponto somos donos da nossa vida ao vivermos num mundo quase totalmente tecnologico
The probabilistic random forest applied to the selection of quasar candidates in the QUBRICS survey
No full textThe number of known, bright (i 2.5) QSOs in the Southern hemisphere is considerably lower than the corresponding number in the Northern hemisphere due to the lack of multiwavelength surveys at δ 2.5 QSOs. The performances of the PRF, currently comparable to those of the CCA, are expected to improve as the number of high-z QSOs available for the training sample grows: results are however already promising, despite this being one of the first applications of this method to an astrophysical context
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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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