1,721,038 research outputs found
Electromagnetic Scattering from Fractal Profiles: the Extended Boundary Condition Method
No full textElectromagnetic Scattering from Fractal Profiles: the Extended Boundary Condition Method
No full textOil spill detection in synthetic aperture radar images using lipschitz-regularity and multiscale techniques
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Land use and damaging hydrological events causing temporal changes in the Sarno River basin: potential for green technologies mitigation by remote sensing analysis
No full textUrban growth will lead cities to adopt best management practices in order to mitigate the relevant effects, such as an amplification of the hydrological cycle. The use of synthetic-aperture radar (SAR) imagery allowed us to demonstrate, over a period of 20 years (1995-2016), a massive urban development with a 70% increase in the built-up area in the Sarno River basin, in southern Italy, the most polluted river in Europe. Contextually, with the collection of an archive of damaging hydrological events that occurred during the same period, it was possible to identify a potential cause-effect relationship between their statistically significant temporal increase and the increase in the impervious area at the catchment scale provided by satellite imagery analysis. In order to restore the pre-urban development hydrological conditions, a scenario analysis was undertaken where the Storm Water Management Model was used to simulate the hydrological effect of a green roof retrofitting landscape design. SAR imagery was furthermore used to explore the potential retrofitting surfaces, leading to the definition of three different conversion scenarios, accounting for 5, 30, and 100% of potential retrofitting surfaces. The study demonstrated that horizontal ellipsis .
Impact of Multiple Layers of High-Permittivity Materials on the EM Fields Transmission for Magnetic Resonance Imaging Applications
No full textHigh-Permittivity Materials have been used to increase and manipulate the radiofrequency field B1 in Magnetic Resonance Imaging scans. In this work we have explored the possibility to enhance the B1 field even more by using High-Permittivity Pads with different permittivities positioned at different distance from the sample. We have tested this hypothesis by optimizing the permittivity of three layers of a 2D analytical solution, where infinitely long concentric cylinders are excited by a conducting wire. As a result, we have found an increase of the B1 field of about 8% in the center of symmetry of the cylinders
Comparison between Dielectric Resonators and a High-Permittivity Helmet to Improve the Transmit Efficiency in the Brain
No full textIn Magnetic Resonance Imaging, it is becoming common to use High-Permittivity Materials to enhance SNR and transmit efficiency. In this work we are going to compare the efficacy of two different solutions to enhance transmit efficiency, one based on an HPM helmet, and another based on dielectric resonators. These solutions have been tested when 4 dipoles are used to generate the fields. Our simulations show an increase of the transmit efficiency in the center of the brain of 23.8 % when the HPM helmet is used, while no improvement was observed for the dielectric resonators
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