1,720,968 research outputs found
Low frequency seismic sensor based on GPS interferometry
No full textThe ground deformation before, during and after a seismic event contains valuable information to understand the mechanics of earthquakes. Traditional seismometry is based upon the integration of an acceleration signal delivered by an elastically suspended mass near the resonance frequency. This approach is optimal for relatively high frequency deformations. However, there is evidence that non-negligible deformations take place at much lower frequencies, and a suitable detection device is therefore needed. To better understand and experiment with a non-accelerometric seismic sensor sensible to low frequency perturbations (10 Hz and below), we have developed a prototype seismometer based on GPS interferometry. Our breadboard consists of six NovAtel/CMC single frequency SmartAntennas configured in a two-dimensional array with spacing ranging between 1 and 5 meters. We have developed a real time software to log data from the six receivers and to compute and interpret the phase differences between pairs of receivers. The knowledge of the nominal coordinates of the receivers is used to solve and to monitor the integer ambiguities. We demonstrated that the data processing at each epoch, from this net, leads to relative coordinates between the receivers with root-mean-square repeatability between 4 and 8 mm horizontally and between 13 to 19 mm vertically. The resulting horizontal strain rates range from 0.8x10E-3 to 8x10E-3 1/s at a frequency of 1 Hz. The sensor is therefore effective only for large earthquakes (magnitude ≥ 5.9 and 7.5 for angular separations of 1� and 10� respectively). The precision of the results is limited mainly by multipath. The effect of multipath can be mitigated using a calibration signal optimized for the site where the sensor is placed
Determinazione della velocità e della direzione di deflusso di una falda freatica in un sito dell'alta pianura veneta mediante l'impiego di metodologie geofisiche
No full textA multi-temporal geophysical survey over a roman thermal complex in Montegrotto Terme (Padua, Northern Italy)
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Confronto tra metodologie radar, magnetiche ed elettromagnetiche per la caratterizzazione di aree archeologiche.
No full textMulti-temporal geophysical survey of a Roman bath complex in Montegrotto Terme (Padova, northern Italy)
No full textBetween 2000 and 2005, severalgeophysicalsurveyswere carriedout by the staffof the Department
ofGeosciences,UniversityofPadova, onthesite oftheTermeNeronianeinMontegrotto, near Padova,
coveringawhole complexof Roman spa buildings.Thiswork representedagood opportunity to compare
the effectiveness of various techniques (ground-penetrating radar, magnetic gradiometry and
electrical resistivity tomography) and to seek the reasons for differing results. Depth, contrast
between composition of the geological background and building materials, good state of structural
preservation, and the lack of settlement following the Roman age supported experimental results.
Oldandmorerecentexcavations, conductedinparallelwiththeUniversityofPadovasurveys, enabled
continual comparisons between geophysicalmodels and evidence from the sit
Microclimate and weathering in cultural heritage: design of a monitoring apparatus for field exposure tests
Full text linkAn innovative experimental method for the long-term monitoring of outdoor microclimate and material decay at cultural heritage sites was developed to aid the formulation of new damage functions and models for climate-change risk assessment. To that end, an apparatus for field exposure tests was designed to monitor a variety of historical building materials in different environmental settings. The data series acquired, i.e., surface temperature and moisture, are compared with the corresponding meteorological datasets on a local and regional scale. The apparatus is designed for supporting also the monitoring of the physical and chemical changes caused by weathering. This novel method is expected to provide insights into the interaction between historical materials and the environment, which can be exploited for the protection and conservation of cultural heritage
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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