Istituto Universitario Di Studi Superiori Di Pavia

About: Istituto Universitario Di Studi Superiori Di Pavia is a education organization based out in Pavia, Italy. It is known for research contribution in the topics: Pulsar & Neutron star. The organization has 162 authors who have published 566 publications receiving 22605 citations.

Assimilation of H-SAF Soil Moisture Products for Flash Flood Early Warning Systems. Case Study: Mediterranean Catchments

Abstract: A reliable estimation of soil moisture conditions is fundamental for rivers' discharge predictions, especially in small catchments where flash floods occur. In this context, microwave remote sensing can be exploited to estimate soil moisture at large scale. These estimates can be used to enhance the predictions of hydrological models using data assimilation techniques. Flash flood early warning systems can, thus, be improved. This study tested the effect of the assimilation of three different ASCAT-derived soil moisture products, processed and distributed within the EUMETSAT H-SAF framework (SM-OBS-1, SM-OBS-2, SM-DAS-2), into a distributed physically based hydrological model (Continuum). The study areas were three Italian catchments, representative of the typical Mediterranean small basins prone to flash floods. The products were first preprocessed in order to be comparable with the model soil moisture state estimate. Subsequently, they were assimilated using three Nudging-based techniques. Then, observed discharges were compared with the modeled one in order to understand the impact of the assimilation. The analysis was executed for a multiyear period ranging from July 2012 to June 2014 in order to test the assimilation algorithms for operational purposes in real-cases scenarios. Findings showed that the assimilation of H-SAF soil moisture products with simple preprocessing and assimilation techniques can enhance discharge predictions; the improvements significantly affect high flows. Although SM-OBS-2 and SM-DAS-1 are added-value products with respect to SM-OBS-1 (respectively, higher spatial and temporal resolution), they may not necessarily perform better. The impact of the assimilation strongly relies on the permanent catchment characteristics (e.g., topography, hydrography, land cover).

Swift monitoring of the central X‐ray source in RCW 103

Abstract: The X-ray source 1E 161348-5055 lies at the centre of the 2-kyr-old supernova remnant RCW 103. Owing to its 24-ks modulation, orders-of-magnitude flux variability over a few months/years and lack of an obvious optical counterpart, IE 161348-5055 defies assignment to any known class of X-ray sources. Starting from 2006 April, Swift observed 1E 161348-5055 with its X-Ray Telescope for ∼2ks approximately once per month. During the five years covered, the source has remained in a quiescent state, with an average observed flux of ∼1.7 x 10 ―12 erg cm ―2 s ―1 (1-10keV),∼20 times lower than the historical maximum attained in its 1999-2000 outburst. The long time-span of the Swift data allows us to obtain an accurate measure of the period of IE 161348-5055 [P = 24030.42(2) s] and to derive the first upper limit on its period derivative (|P| < 1.6 × 10 ―9 s s ―1 at 3σ).

Experimental dynamic response of spherical friction-based isolation devices

Abstract: This article presents a summary of the experimental dynamic response of curved surface sliders as resulting from more than 1000 dynamic tests on about 60 different types of devices performed at the laboratory of the EUCENTRE foundation. Two different kinds of low-friction sliding materials have been employed in the devices, derived from polyamide (PA), or polyethylene (PE) materials.The rate of change of the dynamic friction coefficient as a function of sliding velocity and contact pressure is assessed and the transition phase between dynamic and static friction, with the consequent possible evidence of static/stick-slip phenomena, has been carefully considered.