1,720,957 research outputs found
Resistance of Reinforced Concrete Columns Subjected to Axial Force and Bending
No full textAbstractThe paper presents a method for determining the resistance of cross-sections of reinforced concrete (RC) columns subjected to the axial force and bending. It takes account of the effect of concrete softening in plastic range and the mean compressive strength of concrete fcm. Such members are frequently encountered in engineering practice (pillars, bridges, viaducts). The stress-strain relationship for concrete in compression for short term uniaxial loading is assumed according to Eurocode 2 for nonlinear analysis. This stress-strain relation adequately represents the behaviour of the concrete by introducing four parameters. For reinforcing steel characterized by yield stress fyk, linear-elastic model with hardening in plastic range is applied. In the derivation of the resistance of the cross-sections of columns under consideration the following assumptions are introduced:•plane cross-sections remain plane•elasto-plastic stress/strain relationships for concrete and reinforcing steel are used•the tensile strength of concrete is ignored•the ultimate strains for concrete and reinforcing steel are determined a priori.The resistance of the RC cross-section is reached when either ultimate compressive strain in concrete or ultimate tensile strain in steel is reached anywhere in that section. The analytical formulae for the resistance NRm relating to the axial force and MRm relating to the bending moment are derived by integrating the equilibrium equations of the cross-section, taking account of physical and geometrical relationships as well as the condition of the ultimate limit state. On the basis of a combinatorial approach, twelve possible forms of the stress distribution in the section are considered. Using the derived formulae the interaction curves with the values of the normalized, cross-sectional forces nRm = NRm /(b t fcm) and mRm = MRm /(b t2 fcm) for the rectangular cross-section have been obtained (b, t – dimensions of the rectangle). The obtained formulae describe the cross-section under consideration in the phase of failure. Replacing the mean values fcm and fyk by the corresponding design values fcd and fyd one obtains formulae determining the design values of the normalized cross-sectional forces nR = NR /(b t fcd) and mR = NR /(b t2 fcd). For presentation of the proposed deformation model numerical calculations have been performed. They are presented in the form of interaction diagrams for rectangular cross-sections. Each curve refers to the corresponding value of the reinforcement ratio. The maximum compressive strain in concrete is calculated at the extreme fibre in the compression zone of the section. The points located on the nRm axis are related to pure compression, while on the mRm axis – to pure bending. The occurrence of the tensile strains in the cross-section leads to the crack formation in the concrete. Moreover, these solutions have been compared with those based on the parabolic-rectangular diagram for concrete under compression and with those obtained experimentally by other authors. In a similar way one may obtain interaction diagrams for ring cross-sections. Based on this analysis conclusions are drawn concerning application possibilities of the proposed approach
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
Structural safety assessment of excessively deflected reinforced concrete tower
No full textTematem artykułu jest o cena bezpieczeństwa konstrukcji wieży antenowej typu Moll o wysokości 60 m, użytkowanej jako stacja bazowa telefonii komórkowej. Wieża została zaprojektowana w konstrukcji żelbetowej prefabrykowanej, zamocowanej w fundamencie żelbetowym. Składa się z 5 segmentów rurowych wykonanych w technologii betonu wirowanego. Połączenia segmentów zaprojektowano w postaci specjalnych łączników, składających się z płyt stalowych skręcanych na śruby. Średnica zewnętrzna trzonu wieży przy podstawie wynosi 1,44 m, zaś w poziomie +60 m - 0,40 m. Od montażu zrealizowanego w 2001 r. trzon wieży wykazywał ponadnormatywne wychylenia z pionu. W celu oceny bezpieczeństwa konstrukcji wieży przeprowadzono analizę statyczno-wytrzymałościową jej trzonu żelbetowego metodą naprężeń liniowych w ujęciu normy kominowej PN-88/B-03004 i powiązanej z nią normy PN-77/B-02011, oraz alternatywnie z uwzględnieniem nieliniowości fizycznej betonu i stali, w oparciu o Eurokod 2 oraz związany z nim Eurokod 1. Na tej podstawie stwierdzono, że rozpatrywana wieża spełniała wymogi bezpieczeństwa konstrukcji, natomiast nie spełniała wymagań w zakresie użytkowalności, dotyczących wychylenia z pionu. Oceniono ponadto, że przyczyną nadmiernego wychylenia wieży była niewystarczająca sztywność dwóch górnych segmentów trzonu.The subject of this paper is the structural safety assessment of a reinforced concrete (RC) antenna tower of Moll type 60 m high consisted of 5 tubular segments made of spun concrete. The connections between segments were designed in the form of special joints consisted of steel plates fixed by screws. The outer diameter of the tower shaft varies from 1.44 m at the ground level to 0.4 m at the top. Since the erection in 2001, the tower shaft showed the excessive deflections. To assess the structural safety of the considered tower, the static analysis of its RC shaft was performed by permissible stress method in accordance with Polish standards PN-88/B-03004 and PN-77/B-02011, as well as according to Eurocode 2 and Eurocode 1, by assuming the physical nonlinearity of concrete and reinforcing steel. Based on the obtained results it was concluded that the structural safety requirements for the tower were fulfilled and the excessive deflection of the tower shaft was caused by the insufficient stiffness of its two upper segments
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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