1,741,651 research outputs found
Sound radiation from a generic bypass duct with bifurcations
No full textThe influence of bifurcations in an aero-engine bypass duct on noise radiation was investigated through high-order accurate three-dimensional numerical simulations. The physical process was described by a set of acoustic perturbation equations (APE), with a background mean flow. Four bifurcation arrangements, with an airfoil cross-section, were regularly placed in circumferential direction. Results of the simulations were compared with those of a clean duct case. A circumferential mode of m=12 with radial mode of n=1 and multi-n modes at a source frequency of 1547 Hz were set as acoustic inputs. Acoustic modes
interfered with the bifurcations resulting in a doubled circumferential mode pattern in the near field acoustic pressure distribution and slightly stronger sound
pressure level behind the bifurcations. Far field noise computations indicated 3.2 dB and 2.0 dB sound pressure level increases for radial mode of n=1 and multi-n
modes respectively. The bifurcations did not alter the radiation angle. A comparison was also made between APE and linearlised Euler equations (LEE). Results showed that the APE simulation produced almost identical far field sound
prediction to the LEE, with a small difference (< 0.8dB) at the main radiation peak angle
DTU Wind Turbine Blade Damage Inspection Dataset using Thermography
No full textThis dataset includes blade damage inspection results using passive thermography when the blades are under cyclic loads or in operational wind turbines. The dataset is used in the development of AQUADA and AQUADA PLUS. The related papers are:[1]Chen, X., Shihavuddin, ASM., Madsen, S. H., Thomsen, K., Rasmussen, S., & Branner, K. (2021). AQUADA: Automated quantification of damages in composite wind turbine blades for LCOE reduction. Wind Energy, 24(6), 535-548. https://doi.org/10.1002/we.2587[2]Chen, X., Semenov, S., McGugan, M., Madsen, S. H., Yeniceli, S. C., Berring, P., & Branner, K. (2021). Fatigue testing of a 14.3 m composite blade embedded with artificial defects – damage growth and structural health monitoring. Composites Part A: Applied Science and Manufacturing, 140, [106189]. https://doi.org/10.1016/j.compositesa.2020.106189[3]Chen, X., Janeliukstis, R., & Sarhadi, A. (2022). Thermographic data analytics-based damage characterization in a large-scale composite structure under cyclic loading. Composite Structures, [115525]. https://doi.org/10.1016/j.compstruct.2022.115525 [4] Chen, X., Sheiati S., Shihavuddin, ASM., AQUADA PLUS: Automated Damage Inspection of Cyclic-loaded Large-scale Composite Structures using Thermal Imagery and Computer Vision. Composite Structures https://doi.org/10.1016/j.compstruct.2023.11708
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
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