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Earthquake dynamics from pseudotachylyte microstructure
No full textData Repository for the production of Figure 3 and Table 1 of the manuscript "Earthquake dynamics from pseudotachylyte microstructure" by Aldrighetti S., Pennacchioni G. and Di Toro G
Earthquake dynamics from pseudotachylyte microstructure
Full text linkDuring an earthquake, most of the dissipation of the stored elastic strain energy occurs by fracturing processes and frictional heat along and adjacent to the seismic fault. Information on earthquake energy partitioning and dynamics can be retrieved from the analysis of exhumed faults containing pseudotachylytes (solidified frictional melts produced during seismic faulting). Here, microstructural analysis is carried out on an east-west striking pseudotachylyte-bearing fault of the dextral strike-slip Gole Larghe Fault Zone within the Adamello granitoid pluton (Italian Alps), exhumed from 8–11 km depth. FESEM cathodoluminescence analysis reveals a strong fragmentation of the wall rocks, invisible with other techniques, which decays in the first centimetres from the pseudotachylyte fault-parallel vein. In the northern block the microfracture density is on average low (7448 mm-2) and the microfractures strike preferentially E-W. In contrast, in the southern block microfracture density is on average high (12,120 mm-2), and the microfractures strike preferentially N-S. This asymmetric wall rock damage provides evidence that the microfractures developed as result of the dynamic stress field associated with earthquake rupture propagation. The measured surface area associated with wall rock fracturing and the volume of the pseudotachylyte allow the estimate of the energy dissipated in fracturing processes US (0.015–1.88 MJ m-2) and frictional heat Q (32 MJ m-2), respectively. The comparison between US and Q implies that frictional heat is the major energy sink during rupture propagation in these intracontinental earthquakes
Rietveld refinement using Debye-Scherrer film techniques
No full textThe advent of modern diffractometers has overcome the old film techniques that were used during the past years. One reason is that computer-controlled diffractometers made available data in a formal ready for the analyses, and the intensities obtained do not suffer for non-linear correction and are very much reliable. The Rietveld method also is established on data obtained from Bragg-Brentano diffractometers equipped with scintillation detectors. However recently, a need for speeding up the analyses is growing, and several experiments have been made to use position-sensitive detectors or energy dispersive detectors for data collection. Very little effort has been involved to resume the old film techniques, coupled with microphotometer systems, that can be used potentially as low cost position sensitive detectors. The film method can be easily improved by simple collection strategies and arrangement on the film-scanning side. The Rietveld method has be successfully applied to the data obtained by the Debye-Scherrer film-technique for structure refinement of a corundum and a quartz samples. A comparison with the results obtainable by a standard Bragg-Brentano diffractometer has been made. Another advantage of the present measurement method is that slight preferred orientations can be easily corrected by rotating the capillary sample holder.The advent of modern diffractometers has overcome the old film techniques that were used during the past years. One reason is that computer-controlled diffractometers made available data in a format ready for the analyses, and the intensities obtained do not suffer for non-linear correction and are very much reliable. The Rietveld method also is established on data obtained from Bragg-Brentano diffractometers equipped with scintillation detectors. However recently, a need for speeding up the analyses is growing, and several experiments have been made to use position-sensitive detectors or energy dispersive detectors for data collection. Very little effort has been involved to resume the old film techniques, coupled with microphotometer systems, that can be used potentially as low cost position sensitive detectors. The film method can be easily improved by simple collection strategies and arrangement on the film-scanning side. The Rietveld method has be successfully applied to the data obtained by the Debye-Scherrer film-technique for structure refinement of a corundum and a quartz samples. A comparison with the results obtainable by a standard Bragg-Brentano diffractometer has been made. Another advantage of the present measurement method is that slight preferred orientations can be easily corrected by rotating the capillary sample holder
Advances on NDT methods and technologies for early stage diagnosis of materials
No full textThe early stage diagnoses of material lattices is becoming a crucial requirement where investigation methods and technologies are faced with both aging of components and materials. The mixing effects of wear, fatigue, temperature variation and environment conditions translate into variations of the atomic flux rate and internal rearrangement of grain size and boundaries of lattices. The related lattice measurements (e.g. the d-.spacing is one important among others) become the only one usable for early stage diagnoses of the lattice structural integrity. When such a diagnoses are the base to identify the qualification of material for the use or the re-qualification for the maintenance in the use, new technologies are required, with methods and appropriate concepts shall be used. The authors bid here to describe shortly the historical evolution of methods and techniques since the 70’s, along with the basic tests performed during the early 90’s of the past century. The technological follow up from those tests is reported along with some results which indicate the significant step up of the most recent technology toward the early stage diagnosis of material via on site x-ray diffraction. Further foreseeable development and advances are also mentioned
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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