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Gentile C.,Polytechnic of Milan | Bernardini G.,IDS Ingegneria Dei Sistemi
European Journal of Environmental and Civil Engineering | Year: 2010

Recent progresses in radar techniques and systems have favoured the development of microwave interferometers, suitable to the non-contact measurement of deflections on large structures. The main characteristic of the new radar systems is the possibility of simultaneously measuring the static or dynamic deflection of several points on a large structure with high accuracy. The objectives of the paper are: a) to discuss some radar techniques implemented in the microwave interferometer, in order to highlight advantages and potential issues of the radar-based measurement; b) to illustrate the application of the radar technique in live-load static and ambient vibration tests performed on a full-scale bridge. © 2010 Lavoisier, Paris.

Colombo M.,Polytechnic of Milan | Martinelli P.,Polytechnic of Milan | Zedda R.,ACell | Albertelli A.,ACell | Marino N.,IDS Ingegneria Dei Sistemi
Materials and Design | Year: 2015

The present work studies the dynamic response of mineral-phenolic foam as well as its energy absorption capacity when subjected to shock loading by means of experimental tests and finite element (FE) analysis. Two experimental campaigns are carried out: the first one studies the uniaxial compressive behaviour al low strain rate (1×10-4-1×10-1s-1); in the second campaign the experimental tests are carried out by a shock tube equipment available at Politecnico di Milano with a proper modification of the test set-up. The shock wave generated by the shock tube impinges a steel plate diffuser that is directly in contact with two prismatic foam specimens allowing to reach medium strain rate into the material (50-100s-1). The experimental investigation has shown the strain rate insensitivity of the material in the range considered. Shock tube tests have shown that the material is characterized by a good specific energy absorption (about 300kJ/m3) if compared with other polymeric foams. Explicit finite element analyses have allowed a deeper insight into the mineral-phenolic foam dynamic response. © 2015 Elsevier Ltd.

Severin J.,Consulting Inc. | Severin J.,University of British Columbia | Eberhardt E.,University of British Columbia | Leoni L.,IDS Ingegneria Dei Sistemi | Fortin S.,Teck Highland Valley Copper
Engineering Geology | Year: 2014

Slope monitoring plays an important role in the risk management of large open pit slopes. Historically, displacement data derived from measuring geodetic prisms have been relied upon to delineate the boundaries of potential slope hazards; however that data can be limited by its point-measurement nature. Localized displacements at each prism may be misinterpreted when extended to the behavior of the entire slope, and important displacements between prisms may be overlooked. New technologies like ground-based radar can provide high resolution, full area coverage of a slope in combination with near real-time acquisition and millimeter precision. As a line-of-sight instrument, these tools provide data on displacement magnitudes and rates, but not true direction hence limiting their use in gaining understanding of the kinematics and behavior of the moving slope. This paper describes a novel experiment in which two ground-based synthetic aperture radar systems were simultaneously deployed to record continuous, line-of-sight displacements of an open pit slope in "stereo". The displacement vectors were combined to create a pseudo 3-D displacement map for the slope, which was subsequently used to interpret the influence of a major fault and the rock mass fabric in promoting different kinematic responses. The data collected demonstrates that an improved understanding of the 3-D kinematics of a large rock slope can be achieved using advanced state-of-the-art monitoring techniques to aid mine design. © 2014 Elsevier B.V. All rights reserved.

Mori A.,University of Florence | De Vita P.,IDS Ingegneria Dei Sistemi | Freni A.,University of Florence
IEEE Transactions on Power Delivery | Year: 2011

The electric field generated by power lines is usually evaluated by a simple 2-D model. Due to the presence of buildings or other objects near the power line, measurements are often in disagreement with the model. In this letter, the adaptive integral method (AIM) is used to analyze a power line in a real environment. The presence of a conducting ground plane, as well as a planar dielectric interface, is also efficiently built into the algorithm. © 2011 IEEE.

Freni A.,University of Florence | De Vita P.,IDS Ingegneria Dei Sistemi | Pirinoli P.,Polytechnic University of Turin | Matekovits L.,Polytechnic University of Turin | Vecchi G.,Polytechnic University of Turin
IEEE Transactions on Antennas and Propagation | Year: 2011

Domain-decomposition (DD) for Integral Equation can be achieved by aggregating standard basis functions into specialized basis functions on each sub-domain; this results in a strong compression of the MoM matrix, which allows an iteration-free (e.g., LU decomposition) solution also for electrically large problems. Fast matrix-vector product algorithms can be used in the matrix filling and compression process of the employed aggregate-functions approach: this hybrid approach has received considerable attention in recent literature. In order to quantitatively assess the performance, advantages and limitations of this class of methods, we start by proposing and demonstrating the use of the Adaptive Integral Method (AIM) fast factorization to accelerate the Synthetic Function eXpansion (SFX) DD approach. The method remains iteration free, with a significant boost in memory and time performances, with analytical predictions of complexity scalings confirmed by numerical results. Then, we address the complexity scaling of both stand-alone DD and its combined use with fast MoM; this is done analytically and discussed with respect to known literature accounts of various implementations of the DD paradigm, with nonobvious results that highlight needs and limitations, and yielding practical indications. © 2011 IEEE.

Cerutti A.,IDS Ingegneria dei Sistemi | Bandinelli M.,IDS Ingegneria dei Sistemi | Bientinesi M.,Consorzio Polo Tecnologico Magona | Petarca L.,University of Pisa | And 3 more authors.
Chemical Engineering Transactions | Year: 2013

The importance of heavy oils as energy resource is continuously increasing, thanks to the development of enhanced oil recovery methods, such as thermal recovery. Radiofrequency reservoir heating through a downhole antenna system can be an effective alternative to steam injection methods, giving advantages such as good energy distribution, greater independence from reservoir properties, equipment compactness, high efficiency and possibility to focus the energy on the oil bed. In this paper we present a numerical study of a new electromagnetic heating method, which combines a radiating antenna with a well-reservoir interface structure, called tight shell. The study was conducted adopting dielectric and physical parameters measured on real oil sand samples and heating requirements relative to an actual oil sand reservoir. The study aims to evaluate the optimal operating irradiation frequency, as well as the effectiveness of the tight shell interface. Results show that, with a proper system design, a considerable volume of reservoir can be uniformly heated by a single downhole antenna. Frequencies in the 10-20 MHz range give the best results, and the use of a tight shell made of a low-loss dielectric material surrounding the irradiating element proves extremely efficient in lowering peak temperatures at the radiating well, preserving well completion and extending the heated volume. The use of a tight shell makes also the method much less sensitive to possible dishomogeneities in the dielectric properties of the reservoir material. Copyright © 2013, AIDIC Servizi S.r.l.

Simi A.,IDS Ingegneria dei Sistemi | Manacorda G.,IDS Ingegneria dei Sistemi | Benedetto A.,Rome 3 University
2012 14th International Conference on Ground Penetrating Radar, GPR 2012 | Year: 2012

Ground Penetrating Radar applications for structure surveying started to grow in the 1980s; amongst these, initial civil engineering applications included condition assessment of highway pavements and their foundations, with applications to structural concrete focusing on inspection of bridge decks. There are many factors that can cause or contribute to the damage of the top layer of concrete in bridge decks including the corrosion of steel rebar, freeze and thaw cycles, traffic loading, initial damage resulting from poor design and/or construction, and inadequate maintenance. When applied to the analysis of bridge decks, GPR can be successfully used for detecting internal corrosion of steel reinforcement within the concrete deck, which can be an indicator of poor quality overlay bonding or delamination at the rebar level. Therefore, this equipment has the ability to gain information about the condition of bridge decks in a more rapid and less costly fashion than coring and will perhaps yield a more reliable assessment than current geotechnical procedures. However, this application requires suitably designed equipment; for instance, optimization of antenna orientation to take advantage of signal polarization is an important feature for successfully locating reinforcing bars in a time-depth slice. Novel equipment has recently been developed to enable the non-destructive analysis of bridge decks; the IDS RIS Hi-Bright runs two arrays of high frequency sensors featuring a rapid, but very dense data collection, thus dramatically increasing the resolution of the GPR survey. Antenna dipoles in these arrays are deployed to collect two data sets with orthogonal antenna orientations, one with the electric field parallel to the scanning direction (W), the other perpendicular to it (HH); in this way, the equipment is capable of collecting 16 profiles, 10 cm spaced in a single swath, thus collecting an incredible amount of information. Dedicated data analysis software provides a 2-D tomography of the underground layers and a 3-D view of the surveyed volume. Main output include the determination of pavement and concrete thickness, the detection of moist areas as well as concrete damage and the location of rebars and ducts within the concrete slab. ©2012 IEEE.

Greco M.,IDS Ingegneria Dei Sistemi | Kulpa K.,Warsaw University of Technology | Pinelli G.,IDS Ingegneria Dei Sistemi | Samczynski P.,Warsaw University of Technology
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

This paper presents the concept of Synthetic Aperture Radar (SAR) and Interferemetric SAR (InSAR) georeferencing algorithms dedicated for SAR based augmented Inertial Navigation Architecture (SARINA). The SARINA is a novel concept of the Inertial Navigation System (INS), which utilized the SAR radar as an additional sensor to provide information about the platform trajectory position and compensate an aircraft drift due to Inertial Measurement Unit (IMU) errors, Global Positioning System (GPS) lack of integrity, etc. © 2011 SPIE.

Pasculli D.,IDS Ingegneria Dei Sistemi | Manacorda G.,IDS Ingegneria Dei Sistemi
2015 8th International Workshop on Advanced Ground Penetrating Radar, IWAGPR 2015 | Year: 2015

GPR performance rapidly decreases with time propagation depending on soil characteristics, thus the dynamic range of the system plays a key role in subsurface visibility. Dynamic range mainly depends on Analog-to-Digital Converter (ADC) number of bits and receiver sampling efficiency, but it can be increased by averaging multiple traces (under the condition of uncorrelated external noise). Most time-domain GPRs use stroboscopic sampling to collect high bandwidth signals and this limits the averaging factor. Therefore, high-speed ADCs are very attractive for time-domain GPRs as they enable a large stacking factor. However, the low number of significant bits limits the Signal-to-Noise Ratio (SNR) or renders this advantage negligible. A further alternative is pseudo real-time sampling which combines fast ADCs with trace averaging; in this case, multiple samples are acquired from each radar trace by shifting the sampling trigger, and then re-assembled by a logic circuit. © 2015 IEEE.

Simi A.,IDS Ingegneria Dei Sistemi | Manacorda G.,IDS Ingegneria Dei Sistemi
Proceedings of 2016 16th International Conference of Ground Penetrating Radar, GPR 2016 | Year: 2016

The NeTTUN (New Technologies for Tunnelling and Underground Works) Project involves a consortium of 23 industrial, research & development laboratories and small and medium enterprise organizations across 9 countries in Europe; the ultimate goal is to enable groundbreaking change in the construction and maintenance of tunnels. Most existing ground prediction methods require the stopping of excavation work for several hours, which relegates them to a once per week activity. This generally far exceeds the available nominal idle time required for the construction of a ring in a segmental lined tunnel. NeTTUN aims to develop a fully automated system, that when installed on a tunnel boring machine (TBM), provides identification of large obstacles that can obstruct digging (e.g. other tunnels, cavities, boulders, foundations, archaeological remains, etc.) as well as soil changes (e.g. from gravel to fractured rock). Current methods for predicting geological variations mainly exploit seismic sources and receivers, deployed during pauses in drilling. In contrast, NeTTUN proposes the combined use of a seismic system and a ground prediction radar. The design has to fulfil two conflicting requirements of a large inspection operating range (which requires low frequency sensors) and detection of rock fractures that can be just a few centimeters in length (requiring high frequency sensors), while also dealing with the main issue of the interaction between the metallic TBM cutter head and the sensors. © 2016 IEEE.

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