Due to be launched in late 2021, the Imaging X-ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2–8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode.
In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis—particularly as far as the response to unpolarized radiation and the stability in time are concerned.
COSMO-SkyMed di Seconda Generazione (CSG) is an Earth Observation joint programme of the Italian Space Agency (ASI) and the Italian Ministry of Defense (It-MoD) that will guarantee long term ...activities and continuity of the COSMO-SkyMed first generation program.
Due to be launched in late 2021, the Imaging X-Ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2-8 keV band, complemented with ...imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode. In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis -- particularly as far as the response to unpolarized radiation and the stability in time are concerned.
The paper presents the acquisition and data processing approach for the Ground Penetrating Radar (GPR) and laser scanner surveys carried out within the SOS project (the acronym comes from ‘SOtto ...Siena’, in English ‘Beneath Siena’). SOS is a program aimed to overcome some of the problems and limitations currently present in the study of cities with long-term continuity of life, responding in particular to the need for a better understanding of the city’s ancient fabric and hence to improvements in its conservation by: GPR city survey full coverage (of all the public spaces, streets, squares, courtyards, gardens, etc.), GIS data entry of the historical-archaeological and geoarchaeological knowledge and the development of a 3D Archaeological WEBGIS.The paper discusses the procedure for the creation of a 3D viewer within an already active WEBGIS platform, specifically created for the visualisation and management of archaeological data. The GPR data, once acquired, were exported in 3D in the form of point clouds and subjected to a procedure of cleaning and filtering from noise, so as to eliminate geometries not referable to anomalies and therefore to the presence of buried structures or cavities, and then transformed into mesh to meet the needs of the subsequent process of semantic enrichment. The GPR survey of the underground was flanked by laser scanning of some of the most significant structures in the historic centre (e.g. the cathedral). All 3D geometries were then inserted into the new visualiser via a pipeline using open-source tools and libraries.
► The effective component expected lives strongly influence the optimal solution. ► Battery DoD and Diesel-Generator annual use result important design parameters. ► The optimal solution is ...surrounded by many sub-optimal solutions of similar costs. ► Expected PBP and Regret characterize different sub-optimal technical solutions. ► The opportunity to take economical decisions customized on investors needs is given.
Hybrid wind-diesel stand alone system sizing is considered. The starting point is constituted by a deterministic model able to minimize long-term total costs of the system, accounting also for design parameters affecting expected lives of relevant components. Then, due to the sensitiveness of the solution of the problem to the uncertainty of fuel price time trend, probabilistic techno-economical analyses are developed. Starting from a probabilistic characterization of possible fuel price scenarios, the expected values of economical figures such as Pay Back Period and Regret are introduced by means of suitable models; such figures allow characterizing each solution in a more comprehensive way in order to take final choices. Finally, a case-study system is analyzed.
Advanced and low-cost 3D technologies (Laser Scanner and Digital Photogrammetry) are nowadays widely used in several fields such as Cultural Heritage and Archaeology. In this paper a collaborative ...project between the Archaeological Park of Herculaneum, the CISA (Interdepartmental Services Centre for Archaeology) and the DAAM (Department of Asia, Africa and Mediterranean Studies) of the University “L’Orientale” of Naples is presented. Aim of the project was to find a solution to study the Roman boat discovered in the ancient city of Herculaneum and destroyed by the eruption of Vesuvius in 79 A.D., without altering its state of preservation. Different digital survey techniques were employed to compare different types of sensors. The goal was to obtain an accurate definition of the construction characteristics of the boat thanks to the data fusion.
Atherosclerosis is enhanced in arterial segments exposed to disturbed flow. Perturbed shear stress increases the expression of oxidation-sensitive responsive genes (such as ELK-1 and p-CREB). ...Polyphenolic antioxidants contained in the juice derived from the pomegranate contribute to the reduction of oxidative stress and atherogenesis during disturbed shear stress.
To evaluate the effects of intervention with the Pomegranate Fruit Extract (PFE) rich in polyphones (punicalagin, which is a potent antioxidant) on ELK-1, p-CREB, and endothelial nitric oxide synthase (eNOS) expression induced by high shear stress in vitro and in vivo.
At the doses used in the study, both the PFE and the regular pomegranate juice concentrate reduced the activation of ELK-1 and p-CREB and increased eNOS expression (which was decreased by perturbed shear stress) in cultured human endothelial cells and in atherosclerosis-prone areas of hypercholesterolemic mice. PFE and pomegranate juice increased cyclic GMP levels while there was no significant effect of both compounds on the conversion of L-arginine to L-citrulline. Administration of these compounds to hypercholesterolemic mice significantly reduced the progression of atherosclerosis and isoprostane levels and increased nitrates. This protective effect was relevant with PFE. Vasomotor reactivity was improved and EC(25) values in response to Ach and NONOate were significantly increased in treated mice in comparison to controls.
This study indicates that the proatherogenic effects induced by perturbed shear stress can be also reversed by chronic administration of PFE.
Two dimensional photonic band gap structures on GaAs/AlGaAs, Si
3N
4 and Si/SiO
2 has been fabricated using a 30
keV gallium ion beam. This process is being developed as a viable alternative for fast ...prototyping of high quality 2D photonic crystal devices. The feasibility of high-resolution (down to 80
nm) unit cell fabrication has been demonstrated as well as the longitudinal depth of the holes (more than 600
nm) over a pattern area of 100
×
100
μm and smaller, using FIB milling as well as FIB gas assisted etching. During milling fluorine gas was added in the sample chamber to control the interior shape of the holes and also to reduce the formation of Ga spherical calotte shaped dots. The in-plane photoluminescence emission of some fabricated devices has been optically characterized by exciting the in plane cavities from the top surface of the device by picosecond laser pulses. As expected, by virtue of its higher back mirror reflectivity leading to lower cavity losses, the 2D photonic crystal cavity showed the occurrence of amplified spontaneous emission.
Self-assembled colloidal structures for photonics Chiappini, A.; Carpentiero, A.; Bollani, M. ...
2024 24th International Conference on Transparent Optical Networks (ICTON),
2024-July-14
Conference Proceeding
In this work we present our consolidated results concerning self-assembled colloidal structures as photonic platforms for the development of lasers and optical sensors. In the specific, we will focus ...our attention on two different structures based on complementary configurations: (a) colloidal photonic glasses constituted by colloidal particles assembled in a totally disordered arrangement (b) optical Tamm states (OTS) within the inverse colloidal structure. In particular we report on the fabrication and characterization of two photonic systems; we will discuss how photonic glasses can be used to enhance photoluminescence features of F8BT polymers, while the OTS as suitable optical platforms in order to detect chemical species.
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