1,720,996 research outputs found
Strain gradients in plasma-sprayed zirconia thermal barrier coatings
No full textNeutron diffraction was used to measure the residual strain field in plasma-sprayed zirconia thermal barrier coatings (TBCs). Data were collected at the British neutron spallation source of ISIS (Didcot), on ENGIN, a recently installed TOF (time-of-flight) instrument designed for residual strain depth profiling. Its particular geometry permitted a direct measurement of the interplanar distances of crystallographic planes lying parallel to the component surface as well as the measurement of zero-strain reference samples. The latter were annealed samples of the three present phases: zirconia (top coat), NiCoCrAlY (bondcoat), and copper (substrate). In this way epsilon(33), the strain component perpendicular to the sample surface, was determined at several positions inside the component, for all the present phases. The results of this analysis, consisting of a strain profile throughout the entire cross-section of the coated component, were integrated by those obtained by a destructive testing, performed after TOF data collection, consisting in the measurement of curvature change of the ceramic after substrate removal by chemical attack. (C) 1998 Elsevier Science S.A. All rights reserved
Caratterizzazione non distruttiva della deformazione residua su acciaio saldato, mediante diffrazione neutronica.
No full textFERRAR
A reverse time of flight approach to neutron diffraction residual stress investigation on a UNI-FE510D steel welded plate
No full textThermal diffusivity measurement by thermographic technique for the non-destructive integrity assessment of TBCs coupons
No full textFor thin (200 μm) APS TBCs.
In this work, a semi-quantitative estimation of cracks at the interface of APS TBCs thicker than 300 μmis obtained from thermal diffusivity values measured by using a single side thermographic technique on coupons subjected to thermal cycling.
In fact, during thermal cycling, two phenomena occur: sintering that promotes a significant increase of thermal diffusivity, and cracking that, representing an additional thermal resistance, causes an apparent decrease of thermal diffusivity. The idea presented hereinafter consists in removing the effects of sintering from apparent thermal diffusivity to estimate cracking at the interface
Calorimetric determination of wet snow liquid water content: The effect of test conditions on the calorimeter constant and its impact on the measurement uncertainty
No full textThe liquid water content (lwc) of wet snow is a fundamental parameter in determining snow properties like its strength and adhesion force to surfaces. Among the different methods available for the measurement of the lwc, this paper focuses on melting calorimetry: known masses of hot water and snow are mixed into a thermally insulated container, and the lwc is obtained from the difference between the initial hot water temperature and the final mixing temperature; it is a fast and easy to implement method that requires little equipment, making it suitable for both laboratory and field measurements. Tests with “equivalent” wet snow samples whose liquid water content was known in advance were carried out to assess the method, showing that the liquid water content was overestimated by a variable amount that seemed to depend on the test parameters. To account for the heat capacity of the calorimeter, which was found not to be negligible, a constant in terms of equivalent hot water mass (E) was introduced. However, its value also depended on the test conditions. Hence, a correlation between E and the test parameters was found, and the measurements were repeated using a container of a different material, showing a similar behavior. Eventually, a discussion about the effects of choosing different hot water masses and hot water-to-snow mass ratios on measurement accuracy is provided
Ermanno Grinzato: a survey on thermophysical properties assessment
No full textIn this work, the direct contribution and the inspiring activity of Ermanno Grinzato are resumed, focusing on the field of thermophysical properties evaluation. The main branches, followed in more than 30 years of research for the development of the InfraRed thermography technique, are reported and related to the scientific and industrial panorama at the time of their introduction. Those branches witness the spirit of excitement and the foresight of the solutions proposed, developed and adopted in the laboratory of the National Research Council in Padova. That laboratory was in a broad sense the 'Alma Mater' of a generation of researchers that have been working in the InfraRed field
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
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