1,721,795 research outputs found
Jenkins, G T (George Thomas), VX24298
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/395165Surname: JENKINS. Given Name(s) or Initials: G T (GEORGE THOMAS). Military Service Number or Last Known Location: VX24298. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 18663.228948
Item: [2016.0049.27458] "Jenkins, G T (George Thomas), VX24298
Models for the prediction of rear-arc and forward-arc fan broadband noise in turbofan engines
No full textThis thesis investigates three elements necessary for the prediction of the broadband noise from a turbofan engine due to the interaction between the turbulent rotor wakes with the Outlet Guide Vanes (OGVs). These are (i) the sound radiation from a cascade of closely spaced blades interacting with rotor wake turbulence, (ii) an analysis of the behaviour of hotwire velocity data from a Large Scale Fan Rig (LSFR), (iii) the development of a scheme for the prediction of the blockage due to the transmission of multi mode sound across the rotor necessary for the prediction of noise in the forward-arc. (i) Cascade noise model A noise model is presented for the prediction of rotor wake turbulence with a cascade of OGVs. Similar to other approaches of this kind, computation time becomes excessive at high frequencies as the number of modes required increases. This thesis shows that at sufficiently high frequencies, when at least two modes are cut-on between adjacent blades, the acoustic blade coupling is weak and the cascade sound radiation closely approximates to that of an isolated aerofoil whose radiation can be computed efficiently using single airfoil theory, thereby greatly reducing computation time. (ii) Characteristics of rotor wake turbulence One factor currently limiting accurate fan broadband noise predictions is an understanding of rotor wake turbulence at the OGV leading edge. This thesis analyses in detail recent hotwire velocity data measured in the interstage of an LSFR. The focus here is on assessing the extent of self-preservation in the rotor wake, whereby the mean and turbulent wake characteristics can be deduced at any position downstream of the rotor and at any operating condition from a limited number of measurements. Unlike as previously assumed, this analysis demonstrates insufficient self-preserving behaviour to justify further pursuit of this approach. Rotor wake turbulence must therefore be measured or predicted at each operating condition separately. An analysis procedure is developed by which the characteristics of individual wakes, necessary for broadband noise predictions, may be inferred from rotor wake velocity measurements in situations in which there is significant overlap between adjacent wakes. (iii) Multi mode rotor blockage Noise generated by the OGV propagates to the forward arc by passing upstream through the spinning rotor. This thesis presents a model for the sound power transmission loss associated with crossing the rotor that includes modal frequency scattering effects. It is shown that the results obtained using exact cascade scattering closely agree at low and high frequencies with the results from a relatively simple prediction scheme that assumes that only plane waves propagate through the cascade, thereby ignoring modal scattering effects. The advantage of making this approximation is that the computation is considerably more efficient than a full cascade calculation. At low frequencies, where only plane waves propagate in the gap, exact agreement is obtained between the exact and plane wave models. Close agreement is also observed in the high frequency limit where a large number of cascade modes are cut-on, most of which are well cut-on and hence whose behaviour tends that of the plane wave mode. The three components of the prediction procedure outlined above are combined to perform a prediction of the rear-arc and forward-arc broadband noise from an LSFR. Comparison of the measured and predicted noise spectra are in reasonable agreement with variations with working line and fan speed being reasonably well captured
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
- …
