1,721,013 research outputs found
Heat Generation Effects on Viscoelastic Dampers in Structures
No full textThe first part of this paper is concerned with the response of viscoelastic dampers subjected to transient temperature conditions caused by heat generation during cyclic deformation. Simple tools for modeling viscoelastic materials are discussed and verified using experimental data obtained in a test program on shear dampers using polymer Scotchdamp 109 of The 3M Company conducted at the Laboratory of the Civil Engineering Department of the University of California at Berkely. The second part of this study is a numerical investigation of the effects of heat generation on the response of structures with supplemental viscoelastic dampers with the aim of defining design guidelines for structures incorporating this type of dissipator
Numerical simulation of an adobe wall under in-plane loading
No full textAdobe is one of the oldest construction materials that is still used in many seismic countries, and different construction techniques are found around the world. The adobe material is characterized as a brittle material; it has acceptable compression strength but it has poor performance under tensile and shear loading conditions. Numerical modelling is an alternative approach for studying the nonlinear behaviour of masonry structures such as adobe. The lack of a comprehensive experimental database on the adobe material properties motivated the study developed here. A set of a reference material parameters for the adobe were obtained from a calibration of numerical models based on a quasi-static cyclic in-plane test on full-scale adobe wall representative of the typical Peruvian adobe constructions. The numerical modelling, within the micro and macro modelling approach, lead to a good prediction of the in-plane seismic capacity and of the damage evolution in the adobe wall considered
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
Adobe structures in earthquake zones: Experimental study on the repair of adobe constructions damaged by earthquake loading and the development of an ATENA-GiD model to simulate shaking table tests for these structures
No full textThe aim of this thesis is to apply a reparation method, developed by the Pontificia Universidad Católica del Perú, on an adobe structure damaged by earthquake loading. This loading is applied with a shaking table test. Using these tests an ATENA- GiD model is made which is able to simulate the behavior of adobe houses under earthquake loading. A shaking table test is done to damage an adobe structure, after reparation, the structure is tested again and the test data of the original and repaired building is compared. The ATENA-GiD model is compared with the first shaking table test. The adobe model is made similar to earlier tests performed at the PUCP. The masonry is made with adobe blocks and mortar. The model is dried for 28 days and then subjected to an earthquake loading derived from the May, 1970 earthquake recorded in Lima. The tests consisted of 2 phases, the first phase with a maximum displacement of 30 mm and the second phase with a maximum displacement of 60 mm. Due to this loading, cracks became visible in the structure. These cracks are visible after a second phase, with a maximum displacement of 60 mm. To repair these cracks they are opened and cleaned with a drill and a hammer and pin. After opening, the cracks are repaired using two different methods, the “manual method” and the “silicone method”. The “manual method” consists of manually filling the cracks with the reparation mortar. The “silicone method” is a method where cracks are first covered with silicon and after hardening of the silicon, the reparation mortar is injected in the cracks. After 28 days drying, the structure is tested again with the same signal. Cracks are already visible in the first phase. In the second phase the structure partially collapsed. This is underlined by the data from the two tests. The natural frequency of the walls decreases during the first test. This implies that there is damage in the walls. After repair, the natural frequency goes up, but never reaches the original value. This implies the presence of non-visual damage. In the second test the roof detaches from the walls in an early stage of the test, this due to the non-visible damage that is not repaired and have weakened the structure. The detachment of the roof results in an structure with less stability and strength. Dynamic tests are expensive and time consuming, therefore It is important to find out what finite element software (FEM) can contribute to the research in adobe buildings in earthquake areas. In the recent past, FEM software was used on a very basic scale at the PUCP. With this thesis it is intended to explore the possibilities of using FEM software in the research of adobe buildings. This to further improve the research possibilities on adobe structures with respect to earthquake loading. The model for this thesis is made in ATENA-GiD. Due to the recent development of the scripts for this program, this study is one of the first trails for the program. Because of this, several bugs were detected. During the course of this thesis improvements have been made to the program due to close contact with the developers and the author. In spite of these improvements, the bugs in the program made it only possible to make a very basic model. This model has a coarse mesh and the material is modeled on a macro scale which means that the blocks, mortar and block-mortar interface are smeared out in the continuum. After repair the structure does not have the same behavior as the original test. Due to non visible damage that is not repaired, the structure loses strength and stability after the first test. Besides this, the repaired part is not as strong as the original masonry. Cracks between the longitudinal and transversal wall are very dangerous. The whole construction looses its stability and strength when these cracks are visible. ATENA-GiD can simulate the behavior in the elastic phase. The inelastic phase does not have similar results as with the PUCP tests. Improvements are made to ATENA-GiD throughout the course of this thesis. Due to lack of these improvements this model has a very coarse mesh, which was needed to reduce calculation time. Several updates in the program can now improve calculation time and therefore more time consuming models can be made, which will calculate the inelastic behavior better.Structural and Building EngineeringDesign and ConstructionCivil Engineering and Geoscience
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