1,720,954 research outputs found
Un modello Strut and Tie per lo studio del fenomeno del comportamento a taglio in travi reticolari miste acciaio calcestruzzo
Get PDFWhen we speak about “travi reticolari miste“ we refer to a composite steel-concrete beam made up of a steel truss encased in cast in place concrete. The steel structure is typically composed of a plate or straight bars at the bottom, straight bars at the top and diagonal web bars: all these elements are connected with welded joints in a typical pyramidal shape. These beams have a particular feature: they can bear their own weight and the weight of the slabs without any provisional support during the “first phase” and then they can collaborate with the cast in place concrete during the “second phase”.
The Italian Code - DM 14.01.2008 and Circolare 02.02.2009 n° 617/C.S.LL.PP – deals with this kind of structures in §4.6 “Other materials costructions” and then in “Linee guida per l’utilizzo di travi tralicciate in acciaio conglobate nel getto di calcestruzzo collaborante e procedure per il rilascio dell’autorizzazione all’impiego” (Sept 2011): composite beams are classified in three groups (A – B – C) depending on their features and for each group suitable norms are prescribed. In particular, for “A” beams we can refer to §4.3 of DM 2008 or to Ec4, for “B” beams we can refer to §4.1 of DM 2008 or to Ec2 while “C” beams require the authorization of Italian Superior Council of Public Works.
Welded joints are very important in encased composite steel-concrete structures: the beam behavior depends on forces and stresses that pass through these joints and weldings must have specific geometrical characteristics and dimensions in order to provide an established strength and ductility. However welding process isn’t so easy because of elements geometry: in fact joints connect rounded surfaces, weldings can’t have the exact designed features and this problem represents the weak point of these beams.
“TRR Ponte” was studied in order to realize a different type of encased composite beam in wich weldings could be achieved in a more precise way: in TRR Ponte top and web bars are not directly connected but they are jointed through a steel rectangular gusset plate that becomes a plane surface on which welding process is easier and faster. Furthermore bars are welded to the rectangular plates through corner joints that have precise geometrical characteristics and dimensions: in this way weldings can really provide the required strength and ductility. At the same time connection plates reduce the buckling lengths of compressed elements, that are diagonal and top bars: if slenderness is reduced, the design buckling resistance is higher and so the steel beam is more stable during the first phase, when concrete isn’t casted yet. Then there is another very important aspect: in TRR Ponte beams web bars can be put together and welded to the straight bars trough the connection plates working on a plane and then all the beam can be composed. In this way every step of the productive process is more efficient and functional.
TRR Ponte is made up of S355 steel type elements, so it can be considered an “A” beam following Italian Code and “Linee Guida”: this means that it should be designed as a steel truss beam to calculate its shear resistance. However, even if during the first phase there are only steel elements, in the second phase a composite beam is made up also of concrete and the struts that develop could influence and improve the shear behavior of the element. At the same time, we can’t use reinforced concrete algorithms because they are based on adherence between concrete and steel elements: in “A” composite beams we don’t use roughened steel bar so the bond stress capacity is very low and we need specific models to correctly evaluate composite beams shear resistance. In this research a new shear design model is developed and it is based on the “Strut-and-Tie method” and on the equilibrium equations applied to composite truss nodes.
Experimental tests have shown the development of concrete struts between the rigid joints of the steel truss and so the formation of a composite truss as presumed in the Strut-and-Tie model adopted was confirmed. Also the TRR Ponte failure mechanism was exactly predicted by the design analytical algorithm even if failure beams loads were higher than expected. TRR Ponte shear behavior has been studied also by FEM numerical analysis: the simplified FEM model proposed allow to know the failure mechanism in a fast way and give a collapse load very close to the experimental one.
The fatigue behavior of TRR Ponte could be another important aspect to analyze: joint connections and beam fatigue experimental tests could show new possible applications of TRR Ponte, for example integral bridges. In this type of structures, bearings and expansion joints are eliminated so that the sub-structure (piers and abutments) and the super-structure (deck slub) are made monolithic: composite beams could be used to realize the deck slab because during the first phase they could be connected to the abutments and then in the second phase casting concrete would integrate the structure
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
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
koamabayili/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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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