101,870 research outputs found
Effectiveness of Travelling Slice Modeling in Representing the Continuous Casting Process of Large Product Sections
No full textIt is critical in the metal continuous casting process to estimate the temperature evolution of the casted section along the machine from the meniscus (the point where liquid metal is poured) to the cutting machine, where the product is cut to commercial length. A convenient approximated model to achieve this goal with a feasible computational effort, particularly in the case of large sections, is the so-called travelling slice: the transversal section of casted product is subjected to different thermal boundary conditions (e.g., thermal flux, radiation, convection) that are found during the movement at constant speed from meniscus to the end of machine. In this work, the results obtained with the approximated travelling slice model are analyzed in the favorable case of an axisymmetric section. In this case, the reference model is 2D, whereas the travelling slice model degenerates in a simple 1D model. Three different casted shapes were investigated, rounds with diameters of 200 mm, 850 mm, and 1200 mm, spanning from traditional to only recently adopted product diameter sizes. To properly test the validity of the travelling slice model, other casting speeds were considered, even outside the industrial range. Results demonstrate the advantage of using the travelling slice, particularly the much lower computational cost without sacrificing precision, even at low casting speed and large dimensions
Finite elements prediction of thermal stresses in work roll of hot rolling mills
No full textA simplified numerical approach based on finite elements to compute thermal stresses occurring in work roll of hot rolling mills is here proposed. To decrease both the complexity of the analysis and the computational effort, this approach implements a plane finite element model of the work roll alone, loaded on its surface by the rotating thermal actions due to the cyclic sequence of the conductive heating caused by the contact with hot strip and cooling provided by water jets. Results from thermal analysis are preliminary compared to an analytical solution available in the literature and then applied as thermal input in the subsequent mechanical finite elements simulations, which provide thermal stress in the work roll and the elastic-plastic evolution of elements, close to the work roll surfac
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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3346: Samuel G. Freedman, author, 2013
No full textPhotograph of author Samuel G. Freedman, at NT Daily Slash meeting in the Mayborn School of Journalism at UNT
Geochemical signatures of intense episodic anaerobic oxidation of methane in near-surface sediments of a recently discovered cold seep (Kveithola trough, NW Barents Sea)
No full textAt cold seep environments, the detection of large 34S enrichments within bulk sulphide minerals has been frequently
used as a proxy to infer the vertical migrations of the sulphate-methane transition zone (SMTZ).
Processes related to the oxidative part of the sulphur cycle can alter the original stable sulphur isotope composition
(δ34S) of the solid sulphur phases, in particular at the sediment-water interface. Identification of paleo
and present positions of methane fronts in the sedimentary records requires the use of multiple geochemical
proxies. Authigenic enrichment of Mo has been demonstrated to represent a valid and durable tracer of the past
SMTZ depth fluctuations and of the intensities of the related methane seepages. This study is based on two
closely-spaced short cores collected from the Main Drift of the Kveithola trough, a glacially-carved depression
located in northwestern Barents Sea. Active fluid seepage has been recently reported in this area and a gas flare
was specifically observed in proximity of the sampling sites where the cores object of our study were retrieved. In
order to collect evidences of the possible occurrence of anaerobic oxidation of methane (AOM) at the sedimentwater
interface of the investigated area and infer the entity of the associated methane flux, we combined the
analyses of reduced sulphur species δ34S, total organic carbon and redox-sensitive elements. The negative δ34S
values within the extracted solid sulphur phases (up to −49.1‰ for pyritic sulphur) show that organoclastic
sulphate reduction (OSR) coupled with disproportionation of sulphur intermediates are the only active processes
in the near-surface sediments. However, moderate to strong enrichments of Mo detected in the relatively organic
carbon poor intervals of both cores and the lack of concurrent enrichments of Co, Cu, Ni, V and Zn, usually
associated to OSR-dominated environment, suggested that the sulphidic conditions favouring the Mo enrichments
were produced by AOM. Therefore, we infer that high methane flux events characterized the drift area of
the Kveithola, occasionally moving upward the SMTZ and thus inducing intense AOM in proximity of the sediment-
water interface of this part of the trough. Our results confirmed the validity of sedimentary Mo as an
indicator of the occurrence and intensity of past methane seepages
De la créativité à l’innovation : un problème mal posé ?
No full textInternational audience<div style=""><font face="null"><span style="font-size: 13px;">Cette contribution se propose d’examiner la place et les modalités de </span></font><span style="font-size: 13px; font-family: null;">la créativité dans le processus d’innovation, en tentant d’articuler deux </span><span style="font-size: 13px; font-family: null;">cadres théoriques, l’un se présentant comme une théorie générale de </span><span style="font-size: 13px; font-family: null;">la conception - la théorie C-K -, l’autre comme une théorie de la </span><span style="font-size: 13px; font-family: null;">technologie et de l’intelligence humaine - la thèse TAC - et de tirer de </span><span style="font-size: 13px; font-family: null;">cette réflexion théorique des implications pour accompagner </span><span style="font-size: 13px; font-family: null;">pratiquement l’innovation. Nous nous proposons de tester ces </span><font face="null"><span style="font-size: 13px;">préconisations en déployant une expérience de conception sur le </span></font><span style="font-size: 13px; font-family: null;">véhicule autonome, en nous appuyant sur une méthodologie proposée </span><span style="font-size: 13px; font-family: null;">par Bazzaro et Meyer (2019) visant à intégrer les enjeux </span><span style="font-size: 13px; font-family: null;">environnementaux dans la conception de produit, et revisitée pour </span><span style="font-size: 13px; font-family: null;">tenir compte de réflexions théoriques sur la place de la créativité dans </span><span style="font-size: 13px; font-family: null;">le processus d’innovation.</span></div&g
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