333 research outputs found
Multidimensional mobile mapping and integrated approach for the digitalisation of underground transport infrastructure
No full textThe tunnel industry has started focusing on the maintenance and management challenges of an existing infrastructure. It is an urgent matter in industrialised countries, where the stakeholders’ attention is increasing at a fast pace considering the incidents and the disruptions caused by improper monitoring and maintenance. This paper presents an innovative methodology to survey and inspect existing railway tunnels through multi-dimensional mobile mapping systems. The proposed approach belongs to the digital strategies for infrastructure maintenance. An integrated multidimensional survey system (ARCHITA) allows for collecting information necessary for the diagnostics of a structure with non-destructive tests. Linear cameras, thermographic cameras, and ground-penetrating radars acquire data to be digitalised and manipulated in different IT environments. The results, in terms of the collected data on structural defects, allow for a new approach for the Management and Identification of the Risk for Existing Tunnels (MIRET). The innovative approach aims at a smart integration of information and models for the Facility Management of the transport system. The workflow for the digitalisation and diagnosis from mobile mapping data has been implemented on two 40km-long metro tunnels
Anomalous dark current ideality factor (n > 2) in thin-film solar cells: The role of grain-boundary defects
No full textBy comparing simulated and measured dark I-V characteristics of CIGS cells, we investigate the low-voltage anomalous (> 2) ideality factor, and find that it can be explained by large donor trap concentrations at grain boundaries, and SRH recombination therein, with no need of complex models involving tunneling, coupled traps, etc. We studied 3 different samples, in all cases achieving excellent fit of the non-monotonic ideality factor. The illuminated cell performance also matches the experiments very well. The most important parameter determining value and voltage dependence of the anomalous ideality factor is the peak energy of the grain boundary donor distribution
Landslide Early Warning Systems as Climate Change Adaptation Measures for Rail Infrastructure
No full textRailways represent a significant asset for Italy, with more than 16,000 km of rail lines distributed all over the country. The impacts of extreme weather events can be particularly severe on rail infrastructure because of the highly integrated nature of the rail system. Historical failure of rail infrastructure due to extreme weather events is well documented. In addition, it is to be expected that climate change affects the stability of engineered slopes and have consequences on landslides. Failure of a single asset can result in potential fatalities, large replacement costs, and loss of service. Consequently, Rete Ferroviaria Italiana (RFI), the Italian public limited company for railway transportation, is moving towards risk assessment methods as part of holistic asset management. In this context, ETS Srl has been developing a methodology called MIRETS (Management and Identification of the Risk - ETS), a workflow to connect survey-inspection data for geology, digitalization, diagnostics, and design. Within this framework, a three-phase methodological approach has been developed for the design and the implementation of a landslide early warning system (LEWS) along a strategic railway infrastructure. This study describes the first preliminary results, focusing on the collection and the processing of the input data
Study of the cross-influence between iii-v and iv elements deposited in the same movpe growth chamber
No full textWe have deposited Ge, SiGe, SiGeSn, AlAs, GaAs, InGaP and InGaAs based structures in the same metalorganic vapor phase epitaxy (MOVPE) growth chamber, in order to study the effect of the cross influence between groups IV and III-V elements on the growth rate, background doping and morphology. It is shown that by adopting an innovative design of the MOVPE growth chamber and proper growth condition, the IV elements growth rate penalization due to As “carry over” can be eliminated and the background doping level in both IV and III-V semiconductors can be drastically reduced. In the temperature range 748–888 K, Ge and SiGe morphologies do not de-grade when the semiconductors are grown in a III-V-contaminated MOVPE growth chamber. Critical morphology aspects have been identified for SiGeSn and III-Vs, when the MOVPE deposition takes place, respectively, in a As or Sn-contaminated MOVPE growth chamber. III-Vs mor-phologies are influenced by substrate type and orientation. The results are promising in view of the monolithic integration of group-IV with III-V compounds in multi-junction solar cells
Ornamental stones in the cultural heritage of Campania region (southern Italy): the Vitulano marbles
No full textIrreversible evolution of eumelanin redox states detected by an organic electrochemical transistor: en route to bioelectronics and biosensing
No full textOrg. electrochem. transistors (OECTs) are currently emerging as powerful tools for biosensing, bioelectronics and nanomedical applications owing to their ability to operate under liq. phase conditions optimally integrating electronic and biol. systems. Herein we disclose the unique potential of OECTs for detecting and investigating the elec. properties of insol. eumelanin biopolymers. Gate current measurements on fine aq. suspensions of a synthetic eumelanin sample from 5,6-dihydroxyindole (DHI) revealed a well detectable hysteretic response similar to that of the pure monomer in soln., with the formal concn. of the polymer as low as 10-6 M. Induction of the gate current would reflect electron transfer from solid eumelanin to the Pt-electrode sustained by redox active catechol/quinone components of the polymer. A gradual decrease in gate current and areas subtended by hysteretic loops were obsd. over 5 cycles both in the eumelanin- and DHI-based devices, suggesting evolution of the polymer from a far-from-the-equil. redox state toward a more stable electronic arrangement promoted by redox exchange with the gate electrode. OECTs are thus proposed as valuable tools for the efficient heterogeneous-phase sensing of eumelanins and to gauge their peculiar elec. and redox behavior
Psychological distress and resilience among italian healthcare workers of geriatric services during the COVID-19 pandemic
No full textThe COVID-19 pandemic exposed healthcare workers (HW) to heavy workload and psychological distress. This study was aimed to investigate distress levels among Italian physicians, nurses, rehabilitation professionals and healthcare assistants working in geriatric and long-term care services, and to explore the potential role of resilience as a protective resource. The General Health Questionnaire-12, the Connor-Davidson Resilience Scale, and a demographic survey were completed by 708 Italian HWs. Distress and resilience levels were compared between professionals through ANOVA; the contribution of sex, age, professional role, and resilience to distress was explored through regression analyses. Physicians reported significantly higher resilience and distress levels than rehabilitation professionals and healthcare assistants respectively. Women, HWs aged above 45, physicians, and participants reporting low resilience levels were at higher risk for distress. Findings suggest the importance of supporting HW's resilience to counterbalance the pandemic related distress
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