188 research outputs found

    Railways' stability observed in Campania (Italy) by InSAR data

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    Campania region is characterized by intense urbanization, active volcanoes, subsidence, and landslides; therefore, the stability of public transportation structures is highly concerned. We have app..

    Railways’ Stability Observation by Satellite Radar Images

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    Remote sensing has many vital civilian applications. Space-borne Interferometric Synthetic Aperture Radar has been used to measure the Earth’s surface deformation widely. In particular, Persistent Scatterer Interferometry (PSI) is designed to estimate the temporal characteristics of the Earth’s deformation rates from multiple InSAR images acquired over time. This chapter reviews the space-borne Differential Interferometric Synthetic Aperture Radar techniques that have shown their capabilities in monitoring of railways displacements. After description of the current state of the art and potentials of the available radar remote sensing techniques, one case study is examined, pertaining to a railway bridge in the Campania region, Italy

    river morphology monitoring using multitemporal sar data preliminary results

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    AbstractIn this paper, we test the capability of satellite synthetic aperture radar (SAR) images to enhance the monitoring of river geomorphological processes. The proposed approach exploits the recently introduced Level-α products. These products are bi-temporal RGB composites in which the association color-object, being physical-based, is stable whatever the scene is considered. This favors the detection of temporary rivers' characteristics for classification purposes in a change-detection environment. The case study was implemented on the Orco river (northwest Italy), where a set of 39 COSMO-SkyMed SAR stripmap images acquired from October 2008 to November 2014 was used to monitor channel planform changes. This preliminary study is devoted to assess the suitability of Level-α images for geomorphologist, with particular reference to the detection of phenomena of interest in river monitoring. This is prior for semi-automatic or automatic classification activities

    Radio Frequency MRI coils and safety: how infrared thermography can support quality assurance

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    Abstract Background The safety controls in Resonance Magnetic Imaging (MRI) diagnostic site are numerous and complex. Some of these are contained in international directives and regularly conducted by medical physics expert after acceptance tests, consisting of a series of checks, measurements, evaluations called quality controls (QCs) and made to guarantee the image quality of the equipment. In this context, ensuring that the coils are in proper operating conditions is important to prevent and reduce errors in use and to preserve patient safety. Results A study by thermography was conducted to evaluate temperature changes of MRI coils during Quality Control (QC), in order to prevent any problems for the patient due to Radio Frequency waves. This experiment involves use of a thermal camera to detect temperature variations during MRI scans using head and body coils of two different tomography 1.5 T and 3.0 T static magnetic field. Thermal camera was positioned inside the MRI room to acquire images every 15 s for all the scansions duration. The observations have shown a temperature increase only for body coil of 1.5 MRI tomography, whereas no significative temperature variation has occurred for the other coils under observation. This temperature increase was later related to a fault of such coil. Conclusions The authors believe this simple method useful as first approach, during routinely QCs, to verify coils functioning and so to avoid patient hazards and are preparing a methodological study about functioning of the coils with respect to their temperature variation

    Measurement of the electromagnetic field backscattered by a fractal surface for the verification of electromagnetic scattering models

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    Fractal geometry is widely accepted as an efficient theory for the characterization of natural surfaces; the opportunity of describing irregularity of natural surfaces in terms of few fractal parameters makes its use in direct and inverse electromagnetic (EM) scattering theories highly desirable. In this paper, we present an innovative procedure for manufacturing fractal surfaces and for measuring their scattering properties. A cardboard–aluminum fractal surface was built as a representation of a Weiestrass–Mandelbrot fractal process; the EM field scattered from it was measured in an anechoic chamber. A monostatic radarlike configuration was employed. Measurement results were compared to Kirchhoff approximation and small perturbation method closed-form results that were analytically obtained by employing the fractional Brownian motion to model the surface shape. Matching and discrepancies between theories andmeasurements are then discussed. Finally, fractal and classical surface models are compared as far as their use in the EM scattering is concerned.Postprint (published version

    Use of SAR data for hydro-morphological characterization in sub-Saharan Africa: a case study

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    In this paper we present the rationale and the preliminary results of a research project devoted to the appropriate and innovative use of remotely sensed data for water management in semi-arid regions. The study area is the district of Yatenga, northern Burkina Faso in the sub- Saharan belt of West Africa, where extreme climate conditions cause several problems: drought, floods, soil erosion. The data comes from the Italian Space Agency (ASI) Cosmo-Skymed program, which provides high resolution (1 meter) Synthetic Aperture Radar (SAR) images. Crucial peculiarity of the project is the use of open source software for data processing and hydrological modeling. Two different hydrological models have been selected. The Soil and Water Assessment Tool (SWAT) to be employed for the design of appropriate water management plans and soil erosion mitigation measures. The Width Function Instantaneous Unit Hydrograph (WFIUHD) model can to employed for the prevision of flood events and therefore for the planning of risk mitigation. The paper shows the preliminary results of the project obtained by the processing of the first available high resolution SAR data. In particular, the first step is the realization of a Digital Elevation Model (DEM). GIS tools have been set up for the DEMprocessing in order to derive the needed hydro-morphological basin attributes to support the geo-morphological rainfall- runoff (WFIUHD) modelin

    Use of High Resolution Satellite Images for the Calibration of Hydro-geological Models in Semi-Arid Regions: A Case Study

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    In this paper we present the preliminary results of a project devoted to use hydrologic and remote sensing models and data for water resource management in semi-arid regions. The project is developed in the Sahel region of Burkina Faso, where a set of high resolution synthetic aperture radar (SAR) images was acquired. The rationale of the project along with the preliminary results obtained by the processing of high resolution Cosmo- SkyMed data are presented and discussed

    Hydrological modeling in ungauged basins using SAR data

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    In this paper we propose a methodology devoted to exploit high resolution radars for monitoring water bodies in semi-arid countries. The proposed approach is based on appropriate registration, calibration and processing of SAR data, producing information ready to use by end-users. The obtained results were used to (i) estimate a relationship between surface and volume of water stored in reservoirs and (ii) validate a hydrological model that simulates the time evolution of water availability

    Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils

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    This is the accepted manuscript of the following article: Rafael, R. B. A., Fernández-Marcos, M. L., Cocco, S., Ruello, M. L., Weindorf, D. C., Cardelli, V., and Corti, G. (2018). Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils. Pedosphere 28, 44-58. doi: 10.1016/S1002- 0160(17)60437-5Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions (0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at pH 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size, leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased, corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soilsThis study was mainly supported by the “Applied Research and Multi-sectorial Program” (FIAM) (No. 5.2.1) granted by the Italian Cooperation and Development Agency (ICDA) to the Universidade Eduardo Mondlane. The authors also acknowledge the Polytechnic University of Marche, Italy for the PhD scholarship provided to the first author as well as research funding for this workS
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