1,720,968 research outputs found
Time-Resolved Analysis of the Base Region in Cooled Transonic Turbine Airfoils
No full textHigh pressure turbine stages often work in the transonic regime. Hence the flow may be dominated by airfoil trailing edge shocks. In this paper, a detailed analysis of a test case representative of the trailing edge region of an airfoil is presented. The analysis has been performed reproducing the main characteristics of the flow field occurring at the blade trailing edge. The numerical campaign has been performed using the in-house HybFlow CFD code. Hybrid unstructured grids have been prepared for the selected configurations and special attention have been paid to the wake region discretization. The study started with the steady analysis with null and continuous blowing at several density ratios, on a round trailing edge representative of actual turbine blades. A main-flow Mach number of 1.5 have been initially considered to enhance the compressibility effects. The steady analyses allowed to evaluate the shock intensity variation increasing the coolant density ratio. Then, unsteady simulations have been conducted with both continuous and pulsating coolant at different frequencies. Frequency domain analyses have been performed and the results have been compared with each other. The obtained vortex structures have been also compared with the open literature results. Furthermore, shock intensity variations have been studied and their inclination monitored. For each frequency, the change in the shock intensity have been individuated and compared with the reference value obtained with continuous cooling. The results clarified the effect of continuous blowing on the flow field even far from the blade surface. Furthermore, uncommon vortex shedding structures have been individuated and discussed, depending on the coolant mass-flow rate
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
Pulsating Trailing Edge Coolant Blowing in a High-Pressure Supersonic Turbine to Control Shock Waves
No full textCompact transonic turbine airfoils exhibit fish tail shock waves. The resulting shock boundary layer interactions among airfoils represent aerodynamic loss, and high thermal and structural loads. This paper presents the conclusions of a numerical and experimental research on the use of pulsating coolant to control the shock waves
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
Pulsating Coolant Ejection Effects Downstream of a Supersonic Trailing Edge
No full textTrailing edge blowing is used in a great variety of applications. In particular, high-pressure turbines bleed about 3% of the engine core massflow through a rear slot of the inlet guide vanes. At transonic conditions the coolant flow alters substantially the base region characteristics, and therefore the wake and shocks. Certain pulsating coolant frequencies give rise to exotic vortical shedding structures, not observed when the coolant is continuous. A detailed analysis of the flow field near the trailing edge region has been performed using the in-house HybFlow code. Blunt and circular trailing edges, exposed to continuous blowing (at different rates) were compared by using steady simulations. Both shock intensity and wake loss are discussed in this paper considering pulsating coolant ejection at various frequencies and blowing ratios
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
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