1,721,193 research outputs found
NDT for the diagnosis of modern, historical and archaeological structures
Full text linkThis thesis has been developed with the aim to explore thoroughly potential and limit of the GPR and ERT methods for monitoring heterogeneous structures where different construction materials are combined together.
Firstly we analysed the GPR response, in various construction materials related to different modern, historical or archaeological structures. In particular, three real examples were investigated during the thesis, namely: the Pyramid of Caius Cestius, the Passage of Commodus and the Colle Oppio Ninpheum, all in Rome. According to the different types of material and frequency antennas, different GPR responses and therefore dissimilar degree of resolution and of attenuation was obtained.
In light of this, the interposition between the surface of the investigated medium and the GPR antenna of a dielectric material (e.g. Plexiglas) was performed in order to improve the resolution.
Furthermore, an application of the GPR and ERT methods for monitoring a load test executed on masonry samples was presented. This panels were built up in the laboratory controlled conditions using tuff and bricks (widespread materials employed in Italy for decades for masonry buildings) and also were reproduced in the phase of theoretical modeling. The laboratory samples are reinforced with a conductive fibre fabric, where a high-conductive material (steel wires) is combined together with a dielectric material (basalt fibre).
In order to improve the sample-antenna coupling in the presence of conductive reinforcements, a Plexiglas (polimetilmetacrilato - PMMA) plate was added underneath a 2 GHz antenna. GPR data were acquired along profiles spaced 0.1 m apart and ERT measurements were executed on a 0.1 m regular spaced grid with a dipole-dipole array operating in a three-dimensional configuration. GPR datasets were also analysed in non-conventional mode, by means of the picking of the reflection time of the EM wave from the rear face of the wall samples.
Results show that GPR and electrical resistivity tomography were both able to detect fractures and weakness zones caused by the load application, even though with a higher resolution for the georadar with respect to the geoelectrical method. Moreover, mapping the GPR data in terms of the dielectric constant and mean absolute amplitude is particularly diagnostic to detect the effective fracturing pattern, after the application of the diagonal load. Therefore, GPR and ERT methods can reduce the degree of uncertainty in the detection of fractures, voids or cavities, with respect to the standard processing, by the combined analysis of radargrams, time-slices and resistivity ERT models.
Furthermore, for the GPR laboratory data acquired directly on the reinforced face of samples, it is demonstrated how interposing a layer of dielectric material between the antenna and the structure can substantially improve the antenna coupling and consequently the capability to detect fractures and to reach the rear face of the sample, despite losing resolution in the case of shallow high-conductive layers.
Finally, three-dimensional synthetic simulations on the same samples validate the experimental evidences. Therefore, we demonstrate that this approach can be a reliable tool to monitor static load tests and it can be further extended to the whole load cycle (before, during and after the experiment)
0 Missal de Lorvão - ANTT, Lisboa - Casa Forte L. 154
No full text0 Missal de Lorvão - ANTT, Lisboa - Casa Forte L. 15
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
Fun and serious: an experience with interactive games in times of distance learning.
Full text linkFun and serious: an experience with interactive games in times of distance learning
Ecologia di Quercus ithaburensis Decaisne subsp. macrolepis (Kotschy) Hedge et Yalt nell'area di distribuzione italo-albanese
No full textStipa austroitalica Martinovsky ssp. austroitalica grasslands of Alta Murgia (Apulia) and Murgia Materana (Basilicata)
No full textThis paper deals with grasslands dominated by Stipa austroitalica ssp. austroitalica in the districts of National Park of Alta Murgia (central Apulia) and Regional Park of Murge Materane (south-east of Basilicata). Phytosociological analyses have been carried out in order to contribute to knowledge of these grasslands syntaxonomy. The phytoclimatic outline of the area under study has been obtained by processing the thermal and rainfall data recorded at the weatherstations of Altamura, Castel del Monte (Alta Murgia) and Matera (Murge Materane) and computing bioclimatic indexes (according to the methods of Rivas Martinez and of Montero de Burgos and González Rebollar). The vegetation study has been performed through 31 phytosociological relevés. The matrix, relevés by species, has been analysed by classification and ordination multivariate techniques in order to highlight homogeneous groups. The phytoclimate of the area can be ascribed to the pluvioseasonal-oceanic type of the Mediterranean macrobioclimate, with a mesomediterranean thermotype and a continental tendency. Murge Materane phytoclimate results more thermo-xeric than Alta Murgia one. Phytosociological and statistical multivariate analyses have pointed out two main groups of relevés corresponding to two new associations: Acino suaveolentis-Stipetum austroitalicae e Chamaecytiso spinescentis-Stipetum austroitalicae. These latter have been framed in a new alliance (Hippocrepido glaucae-Stipion austroitalicae) of Scorzonero-Chrysopogonetalia, that gathers calcareous steppe grasslands of Festuco-Brometea, with accentuated Mediterranean characters. The results of this study show the affinity between S. austroitalica ssp. austroitalica grasslands of south-east of Italy and vegetation of trans-Adriatic and north-Adriatic Carso areas. Moreover, they contribute to define the westward part of Scorzonero-Chrysopogonetalia range, which thus would include also the inner part of central Apulia and eastern Basilicata
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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