Innovative Adaptive Techniques for Multi Channel Spaceborne SAR Systems

Synthetic Aperture Radar (SAR) is a well-known technology which allows to coherently combine multiple returns from (typically) ground-based targets from a moving radar mounted either on an airborne or on a space-borne vehicle. The relative motion between the targets on ground and the platform causes a Doppler effect, which is exploited to discriminate along-track positions of targets themselves. In addition, as most of conventional radar, a pulsed wide-band waveform is transmitted periodically, thus allowing even a radar discrimination capability in the range direction (i.e. in distance). For side-looking acquisition geometries, the along-track and the range directions are almost orthogonal, so that the two dimensional target discrimination capabiliy results in the possibility to produce images of the illuminated area on ground. A side-looking geometry consists in the radar antenna to be, either mechanically or electronically, oriented perpendicular to the observed area. Nowadays technology allows discrimination capability (also referred to as resolution) in both alongtrack and range directions in the order of few tenths of centimeters. Since the SAR is a microwave active sensor, this technology assure the possibility to produce images of the terrain independently of the sunlight illumination and/or weather conditions. This makes the SAR a very useful instrument for monitoring and mapping both the natural and the artificial activities over the Earth’s surface. Among all the limitations of a single-channel SAR system, this work focuses over some of them which are briefly listed below: a) the performance achievable in terms of resolution are usually paid in terms of system complexity, dimension, mass and cost; b) since the SAR is a coherent active sensor, it is vulnerable to both intentionally and unintentionally radio-frequency interferences which might limit normal system operability; c) since the Doppler effect it is used to discriminate targets (assumed to be stationary) on the ground, this causes an intrinsic ambiguity in the interpretation of backscattered returns from moving targets. These drawbacks can be easily overcome by resorting to a Multi-cannel SAR (M-SAR) system

Innovative Adaptive Techniques for Multi Channel Spaceborne SAR Systems

Synthetic Aperture Radar (SAR) is a well-known technology which allows to coherently combine multiple returns from (typically) ground-based targets from a moving radar mounted either on an airborne or on a space-borne vehicle. The relative motion between the targets on ground and the platform causes a Doppler effect, which is exploited to discriminate along-track positions of targets themselves. In addition, as most of conventional radar, a pulsed wide-band waveform is transmitted periodically, thus allowing even a radar discrimination capability in the range direction (i.e. in distance). For side-looking acquisition geometries, the along-track and the range directions are almost orthogonal, so that the two dimensional target discrimination capabiliy results in the possibility to produce images of the illuminated area on ground. A side-looking geometry consists in the radar antenna to be, either mechanically or electronically, oriented perpendicular to the observed area. Nowadays technology allows discrimination capability (also referred to as resolution) in both alongtrack and range directions in the order of few tenths of centimeters. Since the SAR is a microwave active sensor, this technology assure the possibility to produce images of the terrain independently of the sunlight illumination and/or weather conditions. This makes the SAR a very useful instrument for monitoring and mapping both the natural and the artificial activities over the Earth’s surface. Among all the limitations of a single-channel SAR system, this work focuses over some of them which are briefly listed below: a) the performance achievable in terms of resolution are usually paid in terms of system complexity, dimension, mass and cost; b) since the SAR is a coherent active sensor, it is vulnerable to both intentionally and unintentionally radio-frequency interferences which might limit normal system operability; c) since the Doppler effect it is used to discriminate targets (assumed to be stationary) on the ground, this causes an intrinsic ambiguity in the interpretation of backscattered returns from moving targets. These drawbacks can be easily overcome by resorting to a Multi-cannel SAR (M-SAR) system

Numerical modeling of interplay between growth folds and fluvial-alluvial erosion-sedimentation processes

The main aim of the present study is to model the interplay between neotectonic growth folds and fluvial-alluvial processes in piedmont areas using an original numerical modeling platform (ERSEDE). ERSEDE allows to quantify the topographic changes in the model along its evolution. The model outputs can be used to carry out detailed analysis on growth strata geometries and geomorphic evolution. The application of models to analyze this kind of interplays is an important tool to understand the evolution of mountain fronts and it can be helpful to calibrate deformation and denudation rates obtained from geomorphic features.Fil: Garcia, Victor Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Cristallini, Ernesto Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Contemporary stress orientations from borehole breakout analysis in the southernmost flat-slab boundary Andean retroarc (32°44' and 33°40'S)

Horizontal stress directions have been determined in the southernmost flat-slab boundary Andean retroarc between 32°44' and 33°40'S within Cuyo Basin, Argentina. These directions were obtained from the borehole breakout analysis of 42 wells using four-arm caliper data. The mean maximum horizontal stress (SHmax) direction for the whole region is 104.1° with a 95% confidence interval of 8.1°. The present-day stress field has an approximately preferred E-W trend maximum horizontal stress direction, consistent with the plate boundary forces (80°) and the topographic forces (near E-W). The calculated SHmax directions are near the expected values, but some local deviations were observed. The SHmax rotates from an E-W orientation in the south to a NW-SE orientation to the north of this sector of the Andean retroarc. A regional variation in the stress field can be observed when these results for the Cuyo Basin are analyzed together with those presented in a previous study in the Neuquen Basin to the south. The maximum horizontal stress varies from ̃NW-NE along this combined section of the Andean retroarc, with the ̃E-W SHmax directions in the northern Neuquen Basin consistent with those observed in the southern sector of Cuyo Basin. These variations in the stress field orientation appear related with the topography geometry. From the analysis between the mean SHmax obtained and the acting forces, it can be concluded that the topographic control on the horizontal stress field seems to be dominant in the Cuyo Basin and in the north of Neuquen Basin. To the south of Neuquen Basin the horizontal stress field should be mainly controlled by the plate boundary forces.Fil: Guzman, Cecilia Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Cristallini, Ernesto Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Contemporary stress orientations in the Andean retroarc between 34°S and 39°S from borehole breakout analysis

In this paper we present the results of the analysis of borehole breakouts from 115 wells drilled within Neuquén Basin in the Andean retroarc between 34° and 39°S (Argentina). The first-order present-day stress orientation in the Andean retroarc is expected to be mainly controlled by the plate boundary forces (azimuth 80°) and the topographic forces (E-W). The obtained maximum horizontal stress (SHmax) has a preferred trend with a resultant direction of azimuth 88.7° and a 95% confidence interval of 13.3° consistent with the expected trend. The horizontal stress trajectory map achieved for this region shows that the SHmax along the study area is not completely uniform. To the north of Colorado River, the SHmax shows an ESE tendency interpreted as significant influenced by the topographic forces. To the south of Colorado River, SHmax has an ENE trend similar to the expected based on plate boundary forces. To the southeast of the region, a NE direction was found, probably showing a basement structural control in the stress field geometry. The stress orientations obtained for the whole region show that plate boundary forces, drag basal, and topographic forces are strongly controlling the stress direction distribution.Fil: Guzman, Cecilia Griselda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Cristallini, Ernesto Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Bottesi, G.. Repsol YPF; Argentin

DVB-S based passive polarimetric ISAR – methods and experimental validation

In this work, we focus on passive polarimetric ISAR for ship target imaging using DVB-S signals of opportunity. A first goal of the research is to investigate if, within the challenging passive environment, different scattering mechanisms, belonging to distinct parts of the imaged target, can be separated in the polarimetric domain. Furthermore, a second goal is at verifying if polarimetric diversity could enable the formation of ISAR products with enhanced quality with respect to the single channel case, particularly in terms of better reconstruction of the target shape. To this purpose, a dedicated trial has been conducted along the river Rhine in Germany by means of an experimental DVB-S based system developed at Fraunhofer FHR and considering a ferry as cooperative target. To avoid inaccuracies due to data-driven motion compensation procedures and to fairly interpret the polarimetric results, we processed the data by means of a known-motion back-projection algorithm obtaining ISAR images at each polarimetric channel. Then, different approaches in the polarimetric domain have been introduced. The first one is based on the well-known Pauli Decomposition. The others can be divided in two main groups: (i) techniques aimed at separating the different backscattering mechanisms, and (ii) image domain techniques to fuse the polarimetric information in a single ISAR image with enhanced quality. The different considered techniques have been applied to several data sets with distinct bistatic geometries. The obtained results clearly demonstrate the potentialities of polarimetric diversity that could be fruitfully exploited for classification purposes

Bioresorbable microspheres as devices for the controlled release of paclitaxel

The release of the anti-cancer drug paclitaxel (PTX) from microspheres of both a bioresorbable poly(ε-caprolactoneoxyethylene- ε-caprolactone) tri-block copolymer and of polyurethanes containing either copolymers with the same composition and different molecular weights or poly(ε-caprolactone) diol as soft segments was studied. The microspheres, both loaded and not with PTX, were prepared by emulsion-evaporation technique, then characterized by SEM and DSC. The quantities of PTX released were measured by HPLC. The results showed slow and very regular releases, which fit very well the Peppas equation, Mt/M? = k · tn, where Mt is the amount of solute released at the time t, M? is the amount of drug released at the plateau condition, k represents the Peppas kinetic constant and n the diffusion order. Most n values are consistent with non-Fickian release mechanisms, with the exceptions of two less hydrophilic polyurethanes

Estructura de la alta Cordillera de San Juan

Fil: Cristallini, Ernesto Osvaldo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

New acrylate terpolymer-based nanoparticles for the release of nucleic acid: a preliminary study

Purpose: Nano-drug delivery systems based on polymeric biomaterials have received considerable interest as drug delivery vehicles. In this work, radical polymerization was carried out in order to obtain nanoparticles based on a new acrylate terpolymer (PBMA-(PEG)MEMA-PDMAEMA). Methods: Nanoparticles were developed in the form both of nanospheres and nanocapsules, an innovative kind of hollow nanoparticles with a great potential because of their low effective density and high specific surface area. The ability of the nanoparticles to load and then release a nucleic acid (DNA) to be used in cancer treatment was also investigated. Results: Scanning electron microscopy analysis showed a spherical shape, nanometric dimensions, and a homogeneous distribution of the nanoparticles, also confirmed by dynamic light scattering measurements. Fourier transform infrared spectroscopy chemical imaging analysis carried out on the nanocapsules before and after removal of the core demonstrated the presence of the cavity. High-performance liquid chromatography analysis confirmed good encapsulation efficiency of DNA both for nanospheres and nanocapsules. Drug release tests showed controlled release kinetics for both the systems with a high release of DNA in the first hours. In vitro MTT assay showed that the particles do not have cytotoxic effects on the cells. Conclusions: The preliminary investigation showed that the terpolymer-based nanoparticles developed in this study could be good candidates to be used as innovative and versatile gene delivery systems