1,721,066 research outputs found
Coupled Numerical Simulations for Seismic Hazard Assessment of Large Opencast Slopes
No full textEarthquake stability assessments of large opencast mine slopes (dimensions exceeding several hundred meters) are complex and non-linear problems, often addressed using pseudo-static approaches that neglect material-induced failures and the role of pore-fluids. In this study, a numerical approach is used to understand the dynamic response of saturated and unsaturated soils. Since the requirements for such simulations are often not yet met by commercial software packages, user-defined finite elements and user-defined material models have been implemented in Abaqus/Standard. To account for the large depth of the finite element model, a scaling procedure of the system of equations is proposed to purge the influence of initial stress. The constitutive model parameters are calibrated based on laboratory tests and by back calculation of downhole measurements. Large-scale fully coupled finite element simulations are performed to study the response of a flooded opencast mine under earthquake loading. The present work illustrates the importance of the pore-fluids treated as independent phases in the context of seismic analysis of slopes. The simulations show strong wave diffraction effects for inhomogeneous dump structures, resulting in smaller displacements in near-surface areas of the slope. Furthermore, it was found that large areas of the dump show a (significant) temporary decrease of effective mean pressure
Strategies to Apply Soil Models Directly as Friction Laws in Soil Structure Interactions
No full textIn this work three different concepts for a direct application of soil models within a frictional contact description are presented. These concepts can be used in conjunction with all different kinds of contact formulations and solution methods. Additionally, all types of plasticity models can be used within these formulations. The advantage of these concepts is shown exemplary in the modeling process of soil-structure interactions where the Ehlers plasticity model for the continuum is now able to describe the soil behavior at the contact surface. The numerical implementation of the new frictional relations is based on the Mortar method and the numerical investigation of a direct shear test shows the reproduction of the typical stress-strain relation of the soil at the contact surface. The work ends with a critical discussion about the different friction formulations and the application of the Ehlers soil model in a direct shear test
Unangenehmes Wummern - TremAc-Forschungsprojekt untersucht Geräuschbelästigung von Windkraftanlagen - Campusreport am 17.05.2016
No full textEin tiefes Wummern, das niemals aufhört. So empfinden manche Anwohner das Geräusch der sich drehenden Rotoren von Windkraftanlagen. Einige berichten über Schlaflosigkeit, andere sogar über Herzrasen als Folge des kaum hörbaren sogenannten Inf-raschalls der Rotoren. Ist das nur Einbildung oder gibt es die Lärm-belästigung durch Windkraftanlagen wirklich? Forscher am Karlsruher Institut für Technologie wollen das jetzt herausbekommen. Mit dem Forschungsprojekt TremAc sollen Erschütterungen und Lärm erstmals gemessen werden
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
Holistic simulation of geotechnical installation processes: benchmarks and simulations
No full textThis book examines in detail the entire process involved in implementing geotechnical projects, from a well-defined initial stress and deformation state, to the completion of the installation process. The individual chapters provide the fundamental knowledge needed to effectively improve soil-structure interaction models. Further, they present the results of theoretical fundamental research on suitable constitutive models, contact formulations, and efficient numerical implementations and algorithms. Applications of fundamental research on boundary value problems are also considered in order to improve the implementation of the theoretical models developed. Subsequent chapters highlight parametric studies of the respective geotechnical installation process, as well as elementary and large-scale model tests under well-defined conditions, in order to identify the most essential parameters for optimizing the process. The book provides suitable methods for simulating boundary value problems in connection with geote chnical installation processes, offering reliable predictions for the deformation behavior of structures in static contexts or dynamic interaction with the soil
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