1,721,009 research outputs found
Integrated Geophysical Techniques for Archaeological Remains: Real Cases and Full Scale Laboratory Example
No full textThe increasing interest in preserving of the archaeological sites requires the integration of a wide spectra of geophysical methodologies for field measurements. In fact, archaeological investigations need multidisciplinary studies to characterize the physical properties of near-surface. In this context, the integration of electromagnetic techniques seems to be one of the most suitable tools. The most suitable geophysical investigation techniques employed for archaeological purposes are the geomagnetic, GPR and resistivity/conductivity (DC and EM) methods. These techniques are not invasive and allow us to obtain high resolution images of subsurface, even if their use is dependent on site and resolution. In general, geomagnetic and EM methods are more adaptive for large survey, in order to obtain fast results with low resolution. On the contrary, GPR shows high resolution information, but for the heavy data process is adapt for small survey areas. The DC methods are not common then the previous ones, but their contribute is important above all in urban area. Anyway, the integration of different geophysical techniques is the best way for field measurements to identify the remains, because each geophysical technique has the ability to define a variation of the physical parameters (electrical conductivity, magnetic susceptibility, dielectric permittivity) which is able to highlight some pattern of the buried object. This kind of approach was applied in several archaeological site. Moreover, the geophysical contrast between archaeological features and surrounding soils sometimes are difficult to define due to problems of sensitivity and resolution related on the subsoil characteristics and limits of geophysical methods. The results obtained in real and laboratory study cases based on archaeogeophysical approach are here discussed
Archaeogeophysical experiments in the large scale laboratory
No full textThe ArchaeoGeophysical techniques are based on the investigation of buried cultural structures and surrounding materials in the archaeological framework. Unfortunately, the geophysical contrast between archaeological features and surrounding soils sometimes are difficult to define due to problems of sensitivity and resolution both related on the characteristic of the subsoil and the geophysical methods. An archaeological experimental activity has been performed in the Hydrogeosite laboratory, a full large scale controlled site consisting on a pool shape structures of 230m3 where archaeological remains have been installed. The laboratory experiment was performed to assess of the capability of EM geophysical techniques to detect archaeological remains placed in the humid/saturated subsoil. The archaeological test site was characterized by remains of Roman times (walls, tombs, roads, harbour, etc.) covered by sediments. In order to simulate lacustrine and wetland condition and to simulate extreme events (for example underwater landslide, fast natural erosion coast, etc.) the phreatic level was varied and various acquisitions for the different scenarios were performed. The integration of electric and electromagnetic data in that conditions allowed us to overcome the limits of each technique in terms of resolution and depth. Moreover, the experiment highlight the uncertainties related on the interpretation of geophysical analysis
Geofisica urbana a Cisternino
No full textLa geofisica applicata gioca un ruolo fondamentale laddove è necessaria un’accurata caratterizzazione del sottosuolo ma non è possibile effettuare prove dirette ed invasive. E’ questo il caso, ad esempio, di contesti storici e culturali dove l’analisi e la caratterizzazione del sottosuolo non può prescindere dalla conservazione e preservazione dei luoghi stessi. Sempre più spesso si sente quindi parlare di “archeo-geophysics”, “urban-geophysics”, e “urban-archaeo-geophysics” quando si fa riferimento all’applicazione di metodi geofisici a contesti archeologici e urbani e, come nel caso di seguito presentato, a contesti
archeologici in ambiente urbano. Vengono qui mostrati, infatti, i risultati di indagini Georadar (GPR) non invasive eseguite nel centro storico di Cisternino e, in particolare, all’interno della Torre Grande (torre normanno-sveva), all’interno della chiesa del Purgatorio e del piazzale antistante la chiesa di san Nicola. Le indagini sono state effettuate con l’intento di identificare strutture appartenenti a
fasi storiche differenti dei tre edifici del patrimonio edilizio e culturale del paese
Sinkhole risk assessment by ERT: The case study of Sirino Lake (Basilicata, Italy)
No full textThe presence of natural or artificial lakes and reservoirs that can drain because of natural phenomena can generate catastrophic events affecting urban and agricultural areas next to the source area. Therefore, geophysical prospecting techniques have been applied in the study of Sirino Lake, which, during the last century, was affected by the sudden opening of small sinkholes, resulting in the almost total draining of the lake and in the sudden increase of water flow rates of distal springs. Two electrical resistivity tomographies (ERTs) were carried out across the lake, using electrode arrays located on land and across the water body. Selfpotential (SP) data were acquired around the lake shore and the surrounding area. The geophysical prospecting contributed significant data toward explaining the unique hydrogeological characteristics of the lake. Integration
of geophysical, geological, hydrogeological, and geomorphological data allowed us to estimate the thickness of the lacustrine deposits beneath the lake, to describe the main patterns of the subsurface fluid flows in the area, and to identify possible water escape routes causing the piping phenomen
Geophysical Techniques for Monitoring Settlement Phenomena Occurring in Reinforced Concrete Buildings
No full textGeophysical investigations could provide a valid tool for the identification of possible causes of settlement phenomena that affect civil buildings. They provide a non-invasive method of obtaining high-resolution information about the subsoil, saving time and money. However, uncertainties related to the accurate interpretation of the acquired data could potentially reduce the value of these methods. For this reason, the integration of non-invasive tests with direct measurements to support geophysical data interpretation is strongly recommended. This is a fundamental step in the process of defining a sufficiently reliable geological model to explain the cause of failure. Among the various geophysical techniques, electrical resistivity tomography and ground penetrating radar offer significant advantages for monitoring the status of the conservation of civil engineering structures and infrastructures. This paper presents the most recent and beneficial advances of the use of electric and electromagnetic geophysical methods in the field of civil engineering, with particular attention to their applications for monitoring subsidence and settlement phenomena. Finally, the possibilities of the joint use of resistivity and electromagnetic methods for studying the causes of the structural decay that affects two precast buildings are monitored and discussed. The results demonstrate the capability of combining non-destructive geophysical techniques with direct data, for evaluating the safety of building constructions and solving geotechnical problems
Urban geophysical approach to characterize the subsoil of the main square in San Benedetto del Tronto town (Italy)
No full textMost historic urban areas have a lack information regarding subsoil and buried structures (such as old utilities, private cellars, etc.). Therefore, when planning new engineering interventions, limited information of subsoil composition leads to greater risk when conserving and reclassifying historic urban areas. Obtaining information about potential sources of risk for infrastructures is important for civil engineering. However, only high-resolution information improves the management of important activities involving historic urban infrastructure. Although direct measurements can alleviate a lack of information concerning the subsoil, they are, generally, expensive, invasive and interferes with everyday use of the site for long periods. Therefore, the use of low or non-invasive technologies to quickly and accurately analyse the subsoil is preferable and strongly recommended. For this purpose, a new discipline, recently termed Urban-Geophysics, is developing rapidly. This paper describes an application of Urban-Geophysics in a historically important Italian town. In order to characterize the subsoil and identify the presence of natural voids and unknown anthropic underground structures such as cellars, an extensive geophysical investigation based on use of Electrical Resistivity Tomography and Ground Penetrating Radar to perform a survey in the town of San Benedetto del Tronto (Marche region, Italy)with a total time frame of around two days was carried out. Previously unknown buried structures and geological discontinuities were highlighted by using these geophysical techniques. In order to support and confirm the interpretation of the geophysical data, geotechnical drillings were carried out. Finally, direct data validated and supported the non-invasive geophysical results. The combined results have provided valuable information to the local authorities and engineers involved in the decision-making process for the construction of new underground structures
Sinkhole risk assessment by ERT: The case study of Sirino Lake (Basilicata, Italy)
No full textThe presence of natural or artificial lakes and reservoirs that can drain because of natural phenomena can generate catastrophic events affecting urban and agricultural areas next to the source area.Therefore, geophysical prospecting techniques have been applied in the study of Sirino Lake, which, during the last century, was affected by the sudden opening of small sinkholes, resulting in the almost total draining of the lake and in the sudden increase of water flow rates of distal springs. Two electrical resistivity tomographies (ERTs) were carried out across the lake, using electrode arrays located on land and across the water body. Self-potential (SP) data were acquired around the lake shore and the surrounding area. The geophysical prospecting contributed significant data toward explaining the unique hydrogeological characteristics of the lake. Integration of geophysical, geological, hydrogeological, and geomorphological data allowed us to estimate the thickness of the lacustrine deposits beneath the lake, to describe the main patterns of the subsurface fluid flows in the area, and to identify possible water escape routes causing the piping phenomena. (C) 2015 Elsevier B.V. All rights reserved
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
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