1,720,961 research outputs found
Axial compression tests on rubble stone masonry reproducing opus incertum of ancient Pompeii
No full textMechanical performance of full-scale Pompeii-like masonry panels
No full textDesigning suitable structural interventions to preserve ancient masonry structures subjected to seismic activity requires a comprehensive and interdisciplinary knowledge of traditional building techniques. The mechanical properties of materials and the shear behaviour of masonry walls are essential parameters to design suitable interventions for the preservation of ancient assets from the seismic action. However, such information is still lacking for the ancient masonry structures at the archaeological site of Pompeii. This study investigated the shear strength of rubble stone masonry panels. The reproduced full-scale masonry complies with the ancient building technique “opus incertum” identified at the Pompeii site. Three panels were built based on a detailed survey of the ancient masonry structures involved in the 79 AD eruption that first emerged during the new excavation work conducted at Regio V. Original rock units from the ruins of the new excavation area and lime and pozzolana-based mortar produced according to the Vitruvius provisions were used to build the panels. In-situ sonic pulse velocity tests and diagonal compression tests were carried out on the panels in order to identify an appropriate correlation between the results of non-destructive and destructive tests. The realization of the panels is described herein and the results of sonic and diagonal compression tests are presented and discussed
Structural Assessment of Ancient Masonry Structures: An Experimental Investigation on Rubble Stone Masonry
No full textNon-destructive investigation procedures are appropriate approaches for the qualitative mechanical assessment of heritage masonry structures. This study aims to contribute to the knowledge of one of the most common ancient masonry typologies, particularly in Roman archaeological sites, the rubble stone masonry, that is the ancient opus incertum, with an extensive experimental program carried out in the archaeological site of Pompeii. The research focused on archaeological masonry structures with different states of preservation and with or without modern interventions. A non-destructive investigation procedure was carried out including detailed geometrical and material surveys, visual inspections and an extensive program of sonic pulse velocity tests, with a total of 1965 acquired velocities. The paper describes the adopted investigation protocol and detailed analysis and discusses the experimental outcomes. Comparisons with available literature data concerning different masonry typologies at the Pompeii site are also presented. Furthermore, the results of the non-destructive investigation have been compared with available mechanical information from destructive and non-destructive tests performed by the authors on Pompeii-like masonry panels. The unique set of data collected may represent a sound tool for the estimation of the mechanical parameters of the ancient masonry structures, which is a crucial step for the definition of preservation actions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Non-destructive and destructive tests on opus incertum masonry panels
No full textThe conservation of ancient masonry structures requires knowledge of their structural behavior. At the same time, the possibility to perform standard mechanical tests on heritage structures is limited by the need for the preservation of the cultural heritage. This paper presents the results of a deep experimental program aimed at the mechanical characterization of masonry panels reproducing the ancient technique opus incertum found at the Pompeii archaeological site. They were built based on the traditional technique by using original rock units and a typical mortar mixture. The experimental program firstly involved sonic pulse velocity tests and diagonal compression tests on three masonry panels, 1.20m x 1.20m x 0.45m. Then, axial compression tests on five masonry specimens extracted from the three panels were carried out. In the following, the main results of the experimental program are presented and discussed and relevant correlations among the results of non-destructive tests and destructive tests are defined to provide a useful tool for a preliminary assessment of the structural behavior of similar ancient masonries
Mechanical Behavior of ancient mortar specimens from Pompeii site
No full textPreservation of archaeological asset in Pompeii site requestsa systematic planning of conservation interventions based on an interdisciplinary knowledge of the built heritage, in the respect of principles of compatibility, reversibility, distinguishability and minimum inter-vention. Nevertheless, a specific knowledge of constructive techniques used by Roman build-ers in the ancient Pompeii is still lacking, especiallywith respectto material mechanical properties. Nowadays, structural interventions are designed based on mechanical properties provided from Italian technical Standardfor existing buildings. In this study, mechanical properties of ancientmortarsfrom Pompeii archaeological siteare investigated. Elevenspecimens of ancientmortars were collected. They come from ma-sonry structures involved in the 79 A.D. Vesuvius’eruption and emerged for the first time as part of thenewarchaeological excavation worksin RegioV, started on May 2018. Further-more, twelvenew lime-based mortars specimens by usingtwo different aggregates were madebased on literature provisionsaboutancientRoman construction techniques. Compressive tests werecarried out on ancientand new mortarsspecimensandthe results are herein pre-sented and discussed
Variations on the Author
Get PDF“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
Get PDFWe 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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