1,720,958 research outputs found
On the numerical modeling of interfaces in engineering applications
No full textDie vorliegende Arbeit behandelt die Simulation und Modellierung von drei Interfacebeschreibungen anhand von verschiedenen Beispielen. Dabei werden unterschiedliche Diskretisierungsverfahren verwendet, wie die Finite Differenzen, Finite Elemente und Isogeometrische Analyse. Zunächst wird der durch Rezeptordiffusion getriebene Endozytosevorgang beschrieben. Als Basis für die Formulierung dient die Diffusionsgleichung. Das resultierende Gleichungssystem wird mithilfe von finiten Differenzen gelöst. Ziel ist es, das Eindringen eines Virus in eine Zelle abzubilden.
Das zweite Beispiel untersucht die thermo-mechanischen Eigenschaften metallischer Hohlkugeln, nachdem diese durch den Sinterprozess zusammengefügt wurden. Die dünnwandigen Kugeln werden als Schalenelemente mit Hilfe der isogeometrischen Analyse modelliert. Der Fokus liegt dabei auf der thermo-mechanischen Kopplung des zugrundeliegenden Materialmodells sowie der geometrischen Beschreibung mittels NURBS-Ansatzfunktionen. Die Simulationen untersuchen den Einfluss verschiedener Parameter und Randbedingungen auf die Steifigkeit und Verformung der versinterten Strukturen.
Als drittes Beispiel wird die Schädigungsentwicklung unter Einwirkung einer geringen Anzahl an Lastzyklen betrachtet (Low Cycle Fatigue). Dafür wird ein Phasen-Feld-Ansatz mit der Plastizität kombiniert.This thesis deals with the simulation and modeling of three interface descriptions by using different examples. Different discretization methods are used, such as finite differences, finite elements and isogeometric analysis. First, the endocytosis process driven by receptor diffusion is described. The diffusion equation serves as the basis for the formulation. The resulting system of equations is solved by using finite differences. The aim is to depict the penetration of a virus into a cell.
The second example investigates the thermo-mechanical properties of metallic hollow spheres after they have been joined together by the sintering process. The thin-walled spheres are modeled as shell elements by using isogeometric analysis. The focus lies on the thermo-mechanical coupling of the underlying material model and the geometric description via NURBS shape functions. The simulations investigate the influence of various parameters and boundary conditions on the stiffness and deformation of the sintered structures.
As a third example, the development of damage under the influence of a small number of load cycles is considered (low cycle fatigue). For this purpose, a phase-field approach is combined with plasticity
Numerical simulation of cyclic deformation behavior of SLM‐manufactured aluminum alloys
Full text linkThe selective laser melting process has already been developed for many metallic materials, including steel, aluminum, and titanium. The quasi‐static properties of these materials have been found to be comparable or even better than their conventionally manufactured counterparts. However, for their reliable application in operational components, their fatigue behavior plays a critical role. This phenomenon is dominated by several process‐related features, such as surface roughness, remnant porosity, microstructure and residual stresses. The present contribution shows a model which relies on an assumption for the Helmholtz free energy and the dissipation potential. To be more precise: the phase‐field method is applied to simulate the damage evolution, whereas plastic effects are modeled in terms of the isotropic hardening. It is assumed that the damage evolution only occurs in the tension mode of a cyclic load, which is achieved by the decomposition of the stored energy. The numerical results give insight into the evolution of plastic deformations and of damage at a material point and for a chosen mesoscopic sample
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
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
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