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This paper reports on a compact, portable, and selective chemical sensor for hazardous vapors at trace levels, which is under development and validation within the EU project H2020 "RISEN". Starting from the prototype developed for a previous EU project, here, we implemented an updated two-stage purge and trap vapor pre-concentration system, a more compact MEMS- based fast gas-chromatographic separation module (Compact-GC), a new miniaturized quartz-enhanced photoacoustic spectroscopy (QEPAS) detector, and a new compact laser source. The system provides two-dimensional selectivity combining GC retention time and QEPAS spectral information and was specifically designed to be rugged, portable, suitable for on-site analysis of a crime scene, with accurate response in few minutes and in the presence of strong chemical background. The main upgrades of the sensor components and functional modules will be presented in detail, and test results with VOCs, simulants of hazardous chemical agents, and drug precursors will be reported and discussed. [ABSTRACT FROM AUTHOR]

The seismic performance of earth dams can nowadays be performed via dynamic analyses using constitutive models of sufficient accuracy in describing cyclic soil behavior. However, a number of assumptions different from soil model affect the problem as a whole. In this paper, a 2D model of a simplified homogeneous earth dam is developed, to assess the influence of bedrock compliance, vertical component of ground motion, stabilizing berms, and initial pore water pressure distribution on its seismic performance, thus providing some guidance on the choices that should be adopted for a safe assessment of the seismic performance of existing earth dams. [ABSTRACT FROM AUTHOR]

In the last decades, Italy has experienced several strong earthquakes, triggering the attention on the high seismic risk associated with the potential instability of large existing earth dams. Under intense seismic events, dam response depends on various factors including the geometry and the type of water retention scheme. This paper explores the influence of these factors, comparing the seismic performance of two idealized earth dams: a homogeneous dam and a zoned dam. The simplified models adopted in the analyses are representative of these two classes of earth dams, often adopted in the sixties to design various dams located in southern Italy. The idealized models, here examined in detail, have comparable heights and foundation soil conditions, differing in terms of water retention scheme. The seismic response of the dams was evaluated through time‐domain nonlinear dynamic analyses in which the same input ground motion, represented by real‐time histories, was applied at the base of the models. It is shown that for highly inelastic systems, such as those at hand, duration of input motion should be accounted for in addition to compatibility criteria with a design elastic response spectrum. Also, different slopes of dam flanks, shear strength mobilization at the end of dam construction and high stiffness contrast at the shells‐core contacts are shown to result in different deformation patterns at the end of earthquake loading. Some peculiarities in the behavior of these classes of earth dams are highlighted in the paper, providing a guidance for the rational assessment of their seismic performance. [ABSTRACT FROM AUTHOR]