Modelling shallow landslide susceptibility by means of a subsurface flow path connectivity index and estimates of soil depth spatial distribution

Topographic index-based hydrological models have gained wide use to describe the hydrological control on the triggering of rainfall-induced shallow landslides at the catchment scale. A common assumption in these models is that a spatially continuous water table occurs simultaneously across the catchment. However, during a rainfall event isolated patches of subsurface saturation form above an impeding layer and their hydrological connectivity is a necessary condition for lateral flow initiation at a point on the hillslope. <br><br> Here, a new hydrological model is presented, which allows us to account for the concept of hydrological connectivity while keeping the simplicity of the topographic index approach. A dynamic topographic index is used to describe the transient lateral flow that is established at a hillslope element when the rainfall amount exceeds a threshold value allowing for (a) development of a perched water table above an impeding layer, and (b) hydrological connectivity between the hillslope element and its own upslope contributing area. A spatially variable soil depth is the main control of hydrological connectivity in the model. The hydrological model is coupled with the infinite slope stability model and with a scaling model for the rainfall frequency–duration relationship to determine the return period of the critical rainfall needed to cause instability on three catchments located in the Italian Alps, where a survey of soil depth spatial distribution is available. The model is compared with a quasi-dynamic model in which the dynamic nature of the hydrological connectivity is neglected. The results show a better performance of the new model in predicting observed shallow landslides, implying that soil depth spatial variability and connectivity bear a significant control on shallow landsliding

The Role of Frequency and Duty Cycle on the Gate Reliability of p-GaN HEMTs

In this letter, we present an extensive analysis on the role of both switching frequency (ranging from 100 kHz to 1 MHz) and duty cycle (from 10% to 90%) on the time-dependent gate breakdown of high electron mobility transistors (HEMTs) with Schottky metal to p-GaN gate. More specifically, results show how the gate lifetime of GaN HEMTs increases by reducing the frequency and the duty cycle of the stressing gate signal (VG). Such behavior is ascribed to the OFF-time, which is responsible to alter the electrostatic potential in the p-GaN layer during the rising phases of VG (from OFF- to ON-state). Findings of this analysis are useful both for further technology improvement and for GaN-based power circuit designers

On the reproducibility and repeatability of laser absorption spectroscopy measurements for δ2H and δ18O isotopic analysis

The aim of this study was to analyse the reproducibility of off-axis integrated cavity output spectroscopy (OA-ICOS)-derived δ2H and δ18O measurements on a set of 35 water samples by comparing the performance of four laser spectroscopes with the performance of a conventional mass spectrometer under typical laboratory conditions. All samples were analysed using three different schemes of standard/sample combinations and related data processing to assess the improvement of results compared with mass spectrometry. The repeatability of the four OA-ICOS instruments was further investigated by multiple analyses of a sample subset to evaluate the stability of δ2H and δ18O measurements. Results demonstrated an overall agreement between OA-ICOS-based and mass spectrometry-based measurements for the entire dataset. However, a certain degree of variability existed in precision and accuracy between the four instruments. There was no evident bias or systematic deviations from the mass spectrometer values, but random errors, which were apparently not related to external factors, significantly affected the final results. Our investigation revealed that analytical precision ranged ±from ±0.56‰ to ±1.80‰ for δ2H and from ±0.10‰ to ±0.27‰ for δ18O measurements, with a marked variability among the four instruments. The overall capability of laser instruments to reproduce stable results with repeated measurements of the same sample was acceptable, and there were general differences within the range of the analytical precision for each spectroscope. Hence, averaging the measurements of three identical samples led to a higher degree of accuracy and eliminated the potential for random deviations

Identification of maladaptive behavioural patterns in response to extreme weather events

Human behaviour has gained recognition as a critical factor in addressing climate change and its impacts. With extreme weather events posing risks to vulnerable communities, understanding cognitive processes driving behaviours becomes essential for effective risk communication. This study focuses on the 2018 "Vaia" storm, which brought unprecedented precipitation and wind velocity to the mountainous regions of North-eastern Italy. Drawing upon the Protection Motivation Theory (PMT) framework, we employ probabilistic models to identify distinct groups with similar behavioural profiles. By administering a web-based survey to 1500 residents affected by the event, we find that threat appraisal is more influential in shaping protective behaviours than coping appraisal. Our findings indicate that by enhancing coping appraisals and discouraging non-protective measures, we can actively mitigate maladaptive responses and promote the adoption of effective adaptation strategies

Analysis of threshold voltage instabilities in semi-vertical GaN-on-Si FETs

We present a first study of threshold voltage instabilities of semi-vertical GaN-on-Si trench-MOSFETs, based on double pulsed, threshold voltage transient, and UV-Assisted C-V analysis. Under positive gate stress, small negative V th shifts (low stress) and a positive V thshifts (high stress) are observed, ascribed to trapping within the insulator and at the metal/insulator interface. Trapping effects are eliminated through exposure to UV light; wavelength-dependent analysis extracts the threshold de-Trapping energy ≈2.95 eV. UV-Assisted CV measurements describe the distribution of states at the GaN/Al2O3 interface. The described methodology provides an understanding and assessment of trapping mechanisms in vertical GaN transistors

Exploration of Gate Trench Module for Vertical GaN devices

The aim of this work is to present the optimization of the gate trench module for use in vertical GaN devices in terms of cleaning process of the etched surface of the gate trench, thickness of gate dielectric and magnesium concentration of the p-GaN layer. The analysis was carried out by comparing the main DC parameters of devices that differ in surface cleaning process of the gate trench, gate dielectric thickness, and body layer doping. . On the basis of experimental results, we report that: (i) a good cleaning process of the etched GaN surface of the gate trench is a key factor to enhance the device performance, (ii) a gate dielectric >35-nm SiO2 results in a narrow distribution for DC characteristics, (iii) lowering the p-doping in the body layer improves the ON-resistance (RON). Gate capacitance measurements are performed to further confirm the results. Hypotheses on dielectric trapping/detrapping mechanisms under positive and negative gate bias are reported.Comment: 5 pages, 10 figures, submitted to Microelectronics Reliability (Special Issue: 31st European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, ESREF 2020

Approaches for handling wicked manufacturing system design problems

Due to complex interdependencies, incomplete information and uncertainty in the manufacturing requirements, manufacturing system design can be described as a wicked problem. A wicked problem is an ill-defined problem, which makes it difficult to determine if a solution has been found and cannot be solved with traditional optimization approaches. This research will present arguments to justify why such manufacturing system design problems can be considered to fall under the definition of wicked problems especially when customer requirements, hence products, evolve over time. Paradigms such as changeable manufacturing, cyber physical and evolvable production systems have emerged to deal with these issues. A critical analysis of these approaches is then presented, which exposes a gap which exists in the design stages of manufacturing systems to adequately support manufacturing system designers in handling the wicked aspect of manufacturing system design problems. This research therefore argues for the importance of developing integrated approaches which consider both business and product evolution aspects when designing manufacturing systems. Finally an integrated approach is contributed which leverages artificial intelligence to support manufacturing system design decision making whilst considering business and product evolutionary aspects.peer-reviewe

Compact Modeling of Nonideal Trapping/Detrapping Processes in GaN Power Devices

Compact modeling of charge trapping processes in GaN transistors is of fundamental importance for advanced circuit design. The goal of this article is to propose a methodology for modeling the dynamic characteristics of GaN power HEMTs in the realistic case where trapping/detrapping kinetics are described by stretched exponentials, contrary to ideal pure exponentials, thus significantly improving the state of the art. The analysis is based on: 1) an accurate methodology for describing stretched-exponential transients and extracting the related parameters and 2) a novel compact modeling approach, where the stretched exponential behavior is reproduced via multiple RC networks, whose parameters are specifically tuned based on the results of 1). The developed compact model is then used to simulate the transient performance of the HEMT devices as a function of duty cycle and frequency, thus providing insight on the impact of traps during the realistic switching operatio

PIANO DI PROGRAMMAZIONE 2022 Attività annuale di Comunicazione istituzionale e Public engagement della Struttura per la comunicazione

Questo documento sintetizza la programmazione 2022 della Struttura per la Comunicazione di Presidenza. l'Istituto Nazionale di Astrofisica (INAF) vuole proseguire anche nel 2022 con decisione sulla strada di un forte engagement del pubblico, intrapresa negli ultimi anni e realizzata attraverso una variegata offerta di prodotti di comunicazione. Focalizzare la programmazione su alcuni argomenti di punta, ricorrenze ed eventi astronomici permetterà di sfruttare con maggiore efficienza la sinergia dei vari canali di comunicazione diretta dell'Ente, che si arricchiranno quest'anno della rivista 'Universi', un vero e proprio house organ di cui sarà cruciale anche definire una puntuale lista di indirizzi istituzionali cui farlo avere, da concertare con la segreteria di presidenza. L’Ufficio Stampa, Media Inaf e il Coordinamento nazionale della comunità di Didattica e Divulgazione – le tre anime della Struttura di Comunicazione di Presidenza – lavoreranno di concerto con Edu Inaf e Play Inaf, ulteriori risorse che ampliano l’impatto della grande ‘potenza di fuoco’ della comunicazione dell’Istituto. Tutto nell'ottica di dare un'immagine quanto mai univoca e identificabile di un Ente che negli anni ha guadagnato una notevole visibilità, grazie alla vasta rete di contatti intrattenuta a tutti i livelli. Un Ente che oggi può, e deve, fare un salto di qualità e rendere la sua azione di comunicazione quanto mai incisiva. L’argomento della nostra ricerca rende il compito più lieve e più oneroso al tempo stesso: mostrare la bellezza dell'Universo in tutta la sua meraviglia e complessità, rendendola intellegibile e vicina a tutti. La strategia in atto vuole essere di breve periodo, tenuto anche conto che la realizzazione di una grande mostra in uno spazio espositivo di prestigio della Capitale non potrà ragionevolmente avvenire prima della fine dell'anno, stante il benestare sul titolo e sul progetto proposto: Macchine del Tempo. L'Inaf ha in programma anche per quest'anno la partecipazione a una fitta serie di eventi e festival. La partecipazione dell'Ente dovrà tener conto dei temi proposti dai vari organizzatori, cercando di declinare i temi di nostro interesse su quelli dei festival, non il contrario. Le attività proposte nella presente programmazione potranno essere modificate su richiesta del Presidente

The ATLAS Readout System for LHC Runs 2 and 3

The ReadOut System (ROS) is a central part of the data acquisition (DAQ) system of the ATLAS Experiment at the CERN Large Hadron Collider (LHC). The system is responsible for receiving and buffering event data from all detector subsystems and serving these to the High Level Trigger (HLT) system via a 10 GbE network, discarding or transporting data onward once the trigger has completed its selection process. The ATLAS ROS was completely replaced during the 2013-2014 experimental shutdown in order to meet the demanding conditions expected during LHC Run 2 and Run 3 (2015-2025). The ROS consists of roughly one hundred Linux-based 2U-high rack-mounted servers equipped with PCIe I/O cards and 10 GbE interfaces. This paper documents the system requirements for LHC Runs 2 and 3 and the design choices taken to meet them. The results of performance measurements and the re-use of ROS technology for the development of data sources, test platforms for other systems, and another ATLAS DAQ system component, namely the Region of Interest Builder (RoIB), are also discussed. Finally performance results for Run 2 operations are presented before looking at the upgrade for Run 3.Comment: 40 pages, 18 figures, journal pape