1,720,972 research outputs found
An engineering model to describe fragments clouds propagating inside spacecraft in consequence of space debris impact on sandwich panel structures
No full textAll spacecraft in Earth orbit are exposed to the risk of impact with micrometeoroids and orbital debris. When such
particles have enough energy to penetrate the hull of the vehicle, clouds of fragments are ejected into spacecraft and
they can eventually compromise the functionality of various components encountered in their flight path. Knowledge
of the clouds' properties (e.g. fragments mass and velocity) is therefore a key factor to obtain accurate predictions of
the response of interior equipment to space debris threat. However, generation and evolution of debris clouds from
hypervelocity impact is a complex phenomenon governed by a large number of parameters, and existing models
mostly refer to fragments originated by impact on simple aluminium plates only, while the few models available for
sandwich panels do not provide information on the fragments mass. In such context, this paper presents an
engineering model describing debris clouds created by space debris impacts on honeycomb sandwich panels
representative of satellites structural bodies. The model consists of a set of empirical equations providing three pieces
of information, i.e. the geometric description of the cloud, the velocity distribution and the mass distribution of the
fragments. The proposed equations are derived from analogous formulas for debris clouds originated by impacts on
simple aluminium plates, by applying proper corrections to account for different materials effects and different
behaviour of sandwich panels compared to plates of same material. The model is finally evaluated by comparing its
predictions with few experimental data on triple wall structures (sandwich panel plus internal equipment cover
plate), where debris clouds exiting the panels’ rear skin are used to assess the failure of the third wall. In this latter
case, the proposed model is also compared with the SRL equations
Lighting and visual experience of artworks: Results of a study campaign at the National Museum of San Matteo in Pisa, Italy
No full textLight is one of the main factors affecting the visual experience of artworks in museums and can determine the success or failure of an art exhibition. The lighting design is not yet extensively recognized as a crucial element of museum exhibitions, but recent research studies show how different lighting arrangements can create different impressions of the artworks and affect the visual experience of museum visitors. This project involved a psychophysical study of two ancient artworks, a painted panel (14th Century) and a marble sculpture (15th Century), exhibited at the National Museum of San Matteo in Pisa, Italy. Each experiment was set up with different lighting arrangements and different luminaires, with the aim of creating different lighting contrast ratios between the analysed artwork and its background. Those lighting arrangements were presented to different groups of observers in order to investigate the trends of personal preference. The results of the surveys pointed out that, on average, the observers preferred lighting arrangements that provide a certain level of contrast, while configurations with high contrast or almost no contrast were evaluated as less pleasant, less interesting and less suitable to enhance the artworks
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
- …
