1,720,966 research outputs found
Crystal plasticity analysis of fatigue-creep behavior at cooling holes in single crystal Nickel based gas turbine blade components
No full textWe build a crystal plasticity finite element framework to investigate slip localisation and fatigue-creep behaviour at the cooling holes of single crystal Nickel (Ni) based components under cyclic thermomechanical loading. The total slip rate is decomposed into a thermally activated dislocation glide rate which dominates at moderate/low temperatures (T) and/or high stresses, and a climb rate which dominates at high temperatures and increases as inelastic strain accumulates. This formulation captures the monotonic and long-term creep response of Ni alloys in the wide range 2
Crystal plasticity analysis of fatigue-creep behavior at cooling holes in single crystal Nickel based gas turbine blade components
No full textWe build a crystal plasticity finite element framework to investigate slip localisation and fatigue-creep behaviour at the cooling holes of single crystal Nickel (Ni) based components under cyclic thermomechanical loading. The total slip rate is decomposed into a thermally activated dislocation glide rate which dominates at moderate/low temperatures (T) and/or high stresses, and a climb rate which dominates at high temperatures and increases as inelastic strain accumulates. This formulation captures the monotonic and long-term creep response of Ni alloys in the wide range 2
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
On the evaluation of the Bauschinger effect in an austenitic stainless steel—The role of multi-scale residual stresses
Get PDFIn this work, a physically based self-consistent model is developed and employed to examine the microscopic lattice response of pre-strained Type 316H polycrystalline austenitic stainless steel subjected to uniaxial tensile and compressive loading. The model is also used to explain the Bauschinger effect observed at the macroscopic length-scale. Formulated in a crystal based plasticity framework, the model incorporates detailed strengthening effects associated with different microstructural elements such as forest dislocation junctions, solute atoms and precipitates on individual crystallographic slip planes of each individual grain within the polycrystal. The elastoplastic response of the bulk polycrystal is obtained by homogenizing the response of all the constituent grains using a self-consistent approach. Micro-plasticity mechanisms and how these influence the Bauschinger effect are illustrated in terms of the role of residual stresses at different length-scales. Overall, predictions are in good agreement with experimental data of the Bauschinger effect and the corresponding meso-scale lattice response of the material, with the latter measured by neutron diffraction. The results demonstrate that transient softening of the material is related to residual stresses at different length scales. In addition, the (Type III) residual stress at the micro-scale slip system level extends the strain range over which the tensile and compressive reloading curves of the pre-strained material merge
Internal strains between grains during creep deformation of an austenitic stainless steel
Get PDFInternal strains that develop between grains during creep of an austenitic stainless steel were measured using in situ neutron diffraction. The secondary creep pre-strained test specimens were considered. Measurements were undertaken before, during and post creep deformation at 550 °C. There was no measurable change of internal strains between grains during in situ creep for 4 h at 550 °C. In addition, the effect of increasing/reducing temperatures in a range from 470 to 550 °C on the internal strains was measured and interpreted with respect to contributions from thermal expansion/contraction. No further internal misfit strains between grains were created when specimen crept during the dwell time at 530, 510, 490 and 470 °C. Results are discussed with respect to (i) the general structure of self-consistent models and (ii) the optimised use of neutron sources for creep studies.</p
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
On the evaluation of the Bauschinger effect in an austenitic stainless steel - The role of multi-scale residual stresses
No full textIn this work, a physically based self-consistent model is developed and employed to examine the microscopic lattice response of pre-strained Type 316H polycrystalline austenitic stainless steel subjected to uniaxial tensile and compressive loading. The model is also used to explain the Bauschinger effect observed at the macroscopic length-scale. Formulated in a crystal based plasticity framework, the model incorporates detailed strengthening effects associated with different microstructural elements such as forest dislocation junctions, solute atoms and precipitates on individual crystallographic slip planes of each individual grain within the polycrystal. The elastoplastic response of the bulk polycrystal is obtained by homogenizing the response of all the constituent grains using a self-consistent approach. Micro-plasticity mechanisms and how these influence the Bauschinger effect are illustrated in terms of the role of residual stresses at different length-scales. Overall, predictions are in good agreement with experimental data of the Bauschinger effect and the corresponding meso-scale lattice response of the material, with the latter measured by neutron diffraction. The results demonstrate that transient softening of the material is related to residual stresses at different length scales. In addition, the (Type III) residual stress at the micro-scale slip system level extends the strain range over which the tensile and compressive reloading curves of the pre-strained material merge
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
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