1,721,061 research outputs found
Non-invasive archaeological exploration in stratigraphically complex rural settings: an example from Ferento (Viterbo, Italy)
No full textThis paper presents the results of a ground penetrating
radar (GPR) survey conducted in the rural area of the
ancient city of Ferento near Viterbo (Northern Latium, Italy),
where the visible ruins testify an uninterrupted history from
the Etruscan to the Medieval period. The soil covering the
ruins has been intensively ploughed, cultivated and used for
pasture over the centuries, and is characterised by a high
content of clay minerals. In this scenario, the use of GPR is
particularly difficult due to both possible ‘false positive anomalies’
and strong signal attenuation. In order to reconstruct the
geometrical shape and size of the geophysical anomalies
related to a medieval dwelling, multi-profile GPR data were
collected in two different areas, using radar equipped with
250-MHz antennas. 2D and pseudo-3D migrated maps were
created and signal velocity analysis was performed to estimate
the target depths. Despite the clayey-calcareous material, the
results show a good signal penetration and allow a clear
reconstruction of the shape of the buried ruins, confirming
that the anomalies are due to medieval buildings located at a
depth in agreement with what was observed on the archaeological
stratigraphy. Furthermore, our study suggests that in
radar data interpretation, caution should be used if the surveyed
area was subjected to prolonged and intensive agriculture
Radio wave techniques for non-destructive archaeological investigations
No full text"Geophysical techniques can be effectively applied to produce an image of buried targets in a host medium, through. the detection of the ‘boundaries’ between materials having different values of a specific physical property. Over the. last 30 years these methods have been increasingly used to detect the presence of archaeological ruins in the. subsurface, thus reducing extensive, destructive, time consuming and expensive excavations. Recently, ground. penetrating radar (GPR) has become the most important physical technique in archaeological investigations. (allowing for the detection of archaeological targets with both very high vertical and horizontal resolution) and has. been successfully applied also to diagnostic purposes in historical buildings and monuments. In this article an. overview of the use of radio waves in archaeology is presented, first introducing the main physical concepts of GPR,. then presenting some examples of its application to detect ancient buried structures, showing the potential and the. limits of such a method.
Coaxial-Cage Transmission Line for Electromagnetic Parameters Estimation
No full text"We present the measurements performed with a. custom coaxial-cage line designed to determine the complex. dielectric permittivity of large samples, made of granular and\/or. liquid materials. The open structure of the cage facilitates the. filling of the line, and allows the uniform compactness of the. granular materials having large grain size. The electromagnetic. parameters of the samples are retrieved using the line scattering. coefficients (S-parameters), measured with a vector network analyzer. in the frequency range 1MHz to 3 GHz. The measurements. are carried out on water, ethanol, and glass beads using the. Boughriet method, which, for non magnetic materials, optimizes. the Nicolson–Ross–Weir algorithm. The results confirm that such. a device accurately estimates the material complex permittivity. in a wide frequency band. However, at very low frequencies and. at frequencies multiple of the line half-wavelength resonances,. the accuracy significantly reduces. In particular, the accuracy. gets worse for materials with high permittivity and low losses.. Nevertheless, for natural geo-materials, usually characterized by. appreciable losses, the coaxial-cage line can effectively be used. to accurately estimate the material electromagnetic properties in. a wide frequency band.
“Dielectric Measurements of Saline Ices: Implications for Jovian Satellites Radar Exploration”.
No full textThe GPR technique for the preventive archaeology: the Monte Porzio Catone case (Rome, Italy)
No full textNon-destructive technique to investigate an archaeological structure: A GPR survey in the Domus Aurea (Rome, Italy)
No full textThe discovery and touristic fruition of the Domus Aurea (Latin for “Golden House”), and the heavy rain led to the arrival of moisture, starting the slow and inevitable process of decay and collapse. Furthermore, inside the Domus Aurea, there are a lot of parts not yet excavated, attracting a continuous and archaeological interest. In order to properly plan the restoration of this building and detect buried archaeological features, a non-destructive technique, like Ground Penetrating Radar (GPR), is extensively and profitably used for its rapid data collection and its high resolution images of contrasting subsurface structural or archaeological materials. The results show not only the presence of internal lesions and detachments of the wall and vault structure, but also the existence of buried archaeological targets; these preliminary results allow future restoration plans in order to prevent the rapid degradation of this important building
A simple inversion model for the estimation of subsurface features of Mars poles
No full textRadar observations from Marsis have demonstrated that Martian Polar Layered Deposits (PLD's) are very transparent to radar waves. Thus, the sounder is able to detect the presence of subsurface reflections in the polar regions below the ice-rich layered deposits. The analysis of radar data makes it possible to gain information about some physical features of Mars surface. In this work an electromagnetic inversion model is used to characterize the shallower structures. This approach assumes that structure consists of layers with parallel plane interfaces and that the electromagnetic properties of the first layer are known a priori. Under these assumptions it is possible to estimate the dielectric permittivity of the subsurface structure. The inversion method has been tested in an area of South Pole and reconstruction results are shown
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