22 research outputs found
Climate change multi-risk assessment for mango cultivation in Sicily, Italy by using bayesian network
Ensuring food security poses a significant challenge for organizations and consultant companies
involved in the agriculture industry or responsible for food programs. This challenge is
particularly relevant in Sicily, Italy, which has a semi-tropical climate. Given the favorable
weather conditions for mango cultivation and other tropical crops, it becomes crucial to consider
measures for safeguarding against potential climate change impacts in the future. Climate
change is expected to bring changes and increased risks in terms of temperature, extreme
events, soil salinity, and irregular rainfall. Amidst this looming threat, there is a growing demand
for a fresh approach and supportive tools to manage risks and mitigate potential damages in
policy-making and decision-making circles. In this study, we employ a robust method known as
Bayesian Network (BN) to effectively capture and model multiple risks under various future
scenarios. By exploring 'what-if' situations, such as the maximum levels of climate-related
variables, the projected BN model is trained and validated using spatially-resolved data from the
Messina region in Sicily. This approach enables us to understand the dynamic variations in localscale
temperature and precipitation, as well as the underlying driving forces, within the
timeframe of 2009-2022. The outputs of the Bayesian Network aid in predicting future trends
in temperature and precipitation levels, thereby supporting the prioritization of mango cultivation and conservation efforts. In general, the findings derived from the BN analysis
provide valuable support for disaster risk management and mitigation strategies in the face of
climate change and extreme events. This tool can further enhance decision-making processes
by integrating the spatial results of the developed model into a user-friendly interface such as
Geographic Information System (GIS), thereby assisting policymakers and decision-makers in
prioritizing Disaster Risk Management and Climate Change Adaptation plans
The thin and medium filters of the EPIC camera on-board XMM-Newton: measured performance after more than 15 years of operation
After more than 15 years of operation of the EPIC camera on board the XMM-Newton X-ray observatory, we have reviewed the status of its Thin and Medium filters. We have selected a set of Thin and Medium back-up filters among those still available in the EPIC consortium and have started a program to investigate their status by different laboratory measurements including: UV/VIS transmission, Raman scattering, X-Ray Photoelectron Spectroscopy, and Atomic Force Microscopy. Furthermore, we have investigated the status of the EPIC flight filters by performing an analysis of the optical loading in the PN offset maps to gauge variations in the optical and UV transmission. We both investigated repeated observations of single optically bright targets and performed a statistical analysis of the extent of loading versus visual magnitude at different epochs. We report the results of the measurements conducted up to now. Most notably, we find no evidence for change in the UV/VIS transmission of the back-up filters in ground tests spanning a 2 year period and we find no evidence for change in the optical transmission of the thin filter of the EPIC-pn camera from 2002 to 2012. We point out some lessons learned for the development and calibration programs of filters for X-ray detectors in future Astronomy missions
Thin-shell plastic lenses for space and laboratory applications
We have identified an inexpensive, readily available, mechanically stable, extremely smooth, elastic, and mechanically uniform plastic suitable for thin film X-ray optics. Polyethylene terephthalate (PET) is easily deformed without losing its elastic properties or surface smoothness. Most important, PET can be coated with mono- or multilayers that reflect X-rays at grazing incidence. We have used these properties to produce X-ray optics made either as a concentric nest of cylinders or as a spiral. We have produced accurately formed shells in precisely machined vacuum mandresl or used a pin and wheel structure to form a continuously wound spiral. The wide range of medical, industrial and scientific applications for our technology includes: a monochromatic X-ray collimater for medical diagnostics, a relay optic to transport an X-ray beam from the target in a scanning electron microscop0e to a lithium-drifted silicon and microcalorimeter detectors and a satellite mounted telescope to collect celestial X-rays. A wide variety of mono- and multilayer coatings allow X-rays up to ~100 keV to be reflected. Our paper presents data from a variety of diagnostic measurements on the properties of the PET foil and imaging results form single- and multi-shell lenses
Thin-shell plastic lenses for space and laboratory applications
We have identified an inexpensive, readily available, mechanically stable, extremely smooth, elastic, and mechanically uniform plastic suitable for thin film X-ray optics. Polyethylene terephthalate (PET) is easily deformed without losing its elastic properties or surface smoothness. Most important, PET can be coated with mono- or multilayers that reflect X-rays at grazing incidence. We have used these properties to produce X-ray optics made either as a concentric nest of cylinders or as a spiral. We have produced accurately formed shells in precisely machined vacuum mandresl or used a pin and wheel structure to form a continuously wound spiral. The wide range of medical, industrial and scientific applications for our technology includes: a monochromatic X-ray collimater for medical diagnostics, a relay optic to transport an X-ray beam from the target in a scanning electron microscop0e to a lithium-drifted silicon and microcalorimeter detectors and a satellite mounted telescope to collect celestial X-rays. A wide variety of mono- and multilayer coatings allow X-rays up to ~100 keV to be reflected. Our paper presents data from a variety of diagnostic measurements on the properties of the PET foil and imaging results form single- and multi-shell lenses
Manufacturing and testing a thin glass mirror shell with piezoelectric active control
Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or silicon in order to keep the total mass within acceptable limits. Optical modules based on thin slumped glass foils are being developed at various institutes, aiming at improving the angular resolution to a few arcsec HEW. Thin mirrors are prone to deform, so they require a careful integration to avoid deformations and even correct forming errors. On the other hand, this offers the opportunity to actively correct the residual deformation: a viable possibility to improve the mirror figure is the application of piezoelectric actuators onto the non-optical side of the mirrors, and several groups are already at work on this approach. The concept we are developing consists of actively integrating thin glass foils with piezoelectric patches, fed by voltages driven by the feedback provided by X-rays. The actuators are commercial components, while the tension signals are carried by a printed circuit obtained by photolithography, and the driving electronic is a multi-channel low power consumption voltage supply developed inhouse. Finally, the shape detection and the consequent voltage signal to be provided to the piezoelectric array are determined in X-rays, in intra-focal setup at the XACT facility at INAF/OAPA. In this work, we describe the manufacturing steps to obtain a first active mirror prototype and the very first test performed in X-rays
Astronomical soft x-ray mirrors reflectivity enhancement by multilayer coatings with carbon overcoating
A number of X-ray astronomical missions of near future will make use of hard X-ray optics with broad-band multilayer
coatings. However multilayer mirrors can be also useful to enhance the effective area of a given X-ray telescope in the
"classical" low energy X-ray band (0.1 – 10 keV), the window where X-ray spectroscopy provides very useful plasma
diagnostics) with a consistent gain with respect to usual single-layer reflectors. Multilayers for soft X-rays are based on
stacks with constant d-spacing (in order to minimize the loss due to the photoelectric effect). A further gain in
reflectivity (however only restricted to the energy range between 0.5 and 4 keV) can be achieved by using a low density
material as a first external layer of the film, with the role of reducing the photoelectric absorption effect when the mirror
acts in total external reflection regime (Carbon is the most performing material for this specific scope). In this paper the
impact of using soft X-ray multilayer mirrors in future X-ray telescopes is discussed, and soft X-ray reflectivity tests
performed on prototype samples presente
A single stage adiabatic demagnetization refrigerator for testing X-ray microcalorimeters
A single stage Adiabatic Demagnetization Refrigerator (ADR), has been set-up at the X-ray Astronomy Calibration
and Testing (XACT) facility of INAF - Osservatorio Astronomico di Palermo G.S. Vaiana, for the
development and testing of cryogenic X-ray detectors for laboratory and astrophysical applications. The ADR
allows to cool detectors at temperatures below 40 mK and to maintain them at constant operating temperature
for many hours. We describe the design and construction of the ADR and present test results and performance
Design and Development of Thin Plastic Foil, Conical Approximation, High Through-out X-Ray Telescope: Light Weight, Thin Plastic Foil, X-Ray Telescopes
We present results from a program to develop an X-ray telescope made from thin plastic shells. Our initial results have been obtained from multi-shell cylindrical lenses that are used in a point-to-point configuration to image the small focal spot of a an X-ray tube on a microchannel plate detector. We describe the steps that led up to the present design and present data from the tests that have been used to identify the properties of the plastic material that make it a suitable X-ray reflector. We discuss two applications of our technology to X-ray missions that are designed to address some of the scientific priorities set forth in NASA's long term plans for high energy astrophysics. One mission will observe in the 1 - 10 keV band, the other will extend up to ca. 100 keV