ISGRI: the INTEGRAL Soft Gamma-Ray Imager

For the first time in the history of high energy astronomy, a large CdTe gamma-ray camera is operating in space. ISGRI is the low-energy camera of the IBIS telescope on board the INTEGRAL satellite. This paper details its design and its in-flight behavior and performances. Having a sensitive area of 2621 cm$^2$ with a spatial resolution of 4.6 mm, a low threshold around 12 keV and an energy resolution of $\sim$ 8% at 60 keV, ISGRI shows absolutely no signs of degradation after 9 months in orbit. All aspects of its in-flight behavior and scientific performance are fully nominal, and in particular the observed background level confirms the expected sensitivity of 1 milliCrab for a 10$^6$s observation.Comment: INTEGRAL A&A special issu

Close coordination of mobile robots using radio beacons: a new concept aimed at smart spraying in agriculture

International audienceMany agricultural tasks are known to be dangerous for human operators, the environment, and human health in general. The increasing pressure both on safety and on production levels motivates the development of new methodologies and technologies. The rising of off-road mobile robots for agricultural application appears to be a promising contribution to required innovations. It both permits to limit the exposure of people to hazardous products and to achieve difficult and repetitive tasks. Nevertheless, to be fully efficient, autonomous robots have to ensure a high level of accuracy, while carrying potentially heavy tools, possibly in harsh conditions. It is especially the case of spraying, for which accuracy is a key challenge for reducing environmental impacts. The use of huge robots for spraying might seem to be a straightforward solution, by simply automating existing machines. Nevertheless, a simple automation does not reduce directly the environmental impact of human activities (soil compaction, energy, reduction of the use of chemical products). Moreover, huge machines are not necessarily an advantage when considering safety aspects (rollover risk and maneuverability). As a result, a solution based on the cooperation of at least two mobile robots, moving from either side of a vine row, is investigated in this paper thanks to Ultra Wide Band (UWB) technology

The Infra-Red Telescope on board the THESEUS mission

International audienceThe Infra-Red Telescope (IRT) on board the Transient High Energy Sky and Early Universe Surveyor (THESEUS) ESA M5 candidate mission will play a key role in identifying and characterizing moderate to high redshift Gamma-Ray Bursts afterglows. The IRT is the enabling instrument on board THESEUS for measuring autonomously the redshift of the several hundreds of GRBs detected per year by the Soft X-ray Imager (SXI) and the X- and Gamma-Ray Imaging Spectrometer (XGIS), and thus allowing the big ground based telescopes to be triggered on a redshift pre-selected sample, and finally fulfilling the cosmological goals of the mission. The IRT will be composed by a primary mirror of 0.7 m of diameter coupled to a single camera in a Cassegrain design. It will work in the 0.7-1.8 {\mu}m wavelength range, and will provide a 10x10 arc min imaging field of view with sub-arc second localization capabilities, and, at the same time, a 5x5 arc min field of view with moderate (R up to ~500) spectroscopic capabilities. Its sensitivity, mainly limited by the satellite jitter, is adapted to detect all the GRBs, localized by the SXI/XGIS, and to acquire spectra for the majority of them

The Infra-Red Telescope on board the THESEUS mission

The Infra-Red Telescope (IRT) on board the Transient High Energy Sky and Early Universe Surveyor (THESEUS) ESA M5 candidate mission will play a key role in identifying and characterizing moderate to high redshift Gamma-Ray Bursts afterglows. The IRT is the enabling instrument on board THESEUS for measuring autonomously the redshift of the several hundreds of GRBs detected per year by the Soft X-ray Imager (SXI) and the X- and Gamma-Ray Imaging Spectrometer (XGIS), and thus allowing the big ground based telescopes to be triggered on a redshift pre-selected sample, and finally fulfilling the cosmological goals of the mission. The IRT will be composed by a primary mirror of 0.7 m of diameter coupled to a single camera in a Cassegrain design. It will work in the 0.7-1.8 {\mu}m wavelength range, and will provide a 10x10 arc min imaging field of view with sub-arc second localization capabilities, and, at the same time, a 5x5 arc min field of view with moderate (R up to ~500) spectroscopic capabilities. Its sensitivity, mainly limited by the satellite jitter, is adapted to detect all the GRBs, localized by the SXI/XGIS, and to acquire spectra for the majority of them

In situ photoreduction of Ag+-ions by TiO2 nanoparticles deposited on cotton and cotton/PET fabrics

The possibility of in situ photoreduction of Ag+-ions using TiO2 nanoparticles deposited on cotton and cotton/PET fabrics in the presence of amino acid alanine and methyl alcohol has been discussed. The possible interaction between TiO2, alanine and Ag+-ions was evaluated by FTIR analysis. The fabrication of TiO2/Ag nanoparticles on both fabrics was confirmed by SEM, EDX, XRD, XPS and AAS analyses. Cotton and cotton/PET fabrics impregnated with TiO2/Ag nanoparticles provided maximum reduction of Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus. Although excellent antibacterial activity was preserved after ten washing cycles, a significant amount of silver leached out from the fabrics into the washing bath. The perspiration fastness assessment revealed that smaller amounts of silver were also released from the fabrics into artificial sweat at pH 5.50 and 8.00. In addition, deposited TiO2/Ag nanoparticles imparted maximum UV protection to fabrics

In situ photoreduction of Ag+-ions on the surface of titania nanotubes deposited on cotton and cotton/PET fabrics

This study discusses the possibility of in situ photoreduction of Ag+-ions on the surface of titania nanotubes (TNTs) deposited on the cotton and cotton/PET fabrics in the presence of amino acid alanine and methyl alcohol. TNTs were synthetized by hydrothermal method. The proposed interaction between titania, alanine and Ag+-ions was based on the results obtained by FTIR measurements. In order to enhance the binding efficiency between TNTs and fibers, the fabrics were previously impregnated with polyethyleneimine. The presence of TNT/Ag nanocrystals on the surface of fibers was proved by SEM, AAS, XRD and XPS. Larger amount of silver was detected on the cotton fabric. Fabricated TiO2/Ag nanocrystals provided maximum reduction of bacteria E. coli which was preserved after five washing cycles despite significant release of silver. The perspiration fastness tests indicated that silver release did not depend on pH. The presence of TNT/Ag nanocrystals imparted maximum UV protection to fabrics