IRIS - Res&Arch Institutional Research Information System Università degli Studi di Perugia
Not a member yet
126129 research outputs found
Sort by
Data-based regional stabilization of linear systems with saturating actuators
No full textData-based asymptotic stabilization of unknown discrete-time linear systems with saturating actuators is addressed. The proposed approach relies on an explicit sector-bounded representation of the closed-loop system built from noisy state-input data. Relying on this novel representation, sufficient conditions in the form of linear matrix inequalities are established to ensure closed-loop regional asymptotic stability. These conditions are used to formulate a convex optimal controller design that allows one to maximize the region of attraction.Two numerical examples illustrate the applicability of the proposed results
The role of personality in multi-domain environmental perception: An occupant-centric approach
No full textThe built environment accounts for nearly one-third of global energy demand, underscoring the need to enhance building performance through strategies that integrate both technological solutions and human factors. Occupants play a pivotal role in this process, as their comfort and well-being are shaped by complex interactions across multiple environmental domains. This study investigates cross-domain effects between thermal and acoustic environments, with a specific focus on how personality traits modulate perceptual responses. An experimental campaign was conducted in a controlled test room under two thermal conditions: a neutral phase (21 °C) and a mild discomfort phase (23 °C). In each phase, 25 participants evaluated seven soundscapes with distinct acoustic characteristics, ranging from natural to anthropogenic. Continuous monitoring of environmental parameters ensured accurate boundary conditions, while personality traits were assessed to capture inter-individual variability. Results show that even slight thermal variations influence acoustic perception, producing systematic negative shifts in the evaluation of the main soundscape's descriptors across phases. Cluster analysis of personality traits identified two groups: one with higher emotional stability and openness, and another with stronger neurotic tendencies. These groups exhibited divergent perceptual patterns, with neurotic individuals reporting greater sensitivity to anthropic and chaotic soundscapes, and emotionally stable participants showing stronger appreciation for natural ones. Overall, the findings demonstrate that occupant perception cannot be understood through single-domain analyses alone. Integrating cross-domain interactions and personality-driven variability into adaptive comfort models and occupant-centric design strategies is essential to support buildings that are both energy-efficient and responsive to human diversity
Power hardware in the loop-based lifetime assessment of hybrid energy storage systems: A novel realistic approach
No full textReliable and cost-effective energy storage is essential for grid applications, but lithium-ion batteries face lifetime limitations due to cycling stress, temperature effects, and high power ramping. This paper presents a novel Power Hardware-in-the-Loop (PHIL) approach for experimentally assessing battery aging in Hybrid Energy Storage Systems (HESS) that combine batteries with flywheels. The proposed setup enables realistic emulation of field conditions and long-term degradation testing. Two configurations are experimentally evaluated: a standalone battery system and a hybrid flywheel-battery system with equivalent energy capacity. Results show that the HESS configuration significantly reduces power ramping and depth of discharge, resulting in lower degradation rates than a standalone battery. Furthermore, a Levelized Cost of Storage (LCOS) analysis confirms that the HESS achieves superior lifetime economics under realistic operating conditions, particularly under end-of-life criteria
Towards hydrate-based CO2 storage in marine environments: salinity effects in CO2-H2O binary systems
No full textThis study investigates CO2 hydrate formation in marine environments using controlled experiments in pure water, 3 wt% NaCl, and 4 wt% NaCl solutions. Gas uptake decreased from 31.51 % in pure water to 13.97 % and 5.30 % in 3 wt% and 4 wt% NaCl solutions, respectively, as well as formation density (from 19.36 kg/m3 to 8.71 kg/m3 and 3.61 kg/m3). A non-linear effect was observed wherein 4 wt% NaCl solutions with slightly higher hydrate formation than 3 wt% under certain conditions, suggesting complex interdependencies between salinity, pressure and temperature. The pressure decline rate (Delta P/Delta t) varies with pressure and salinity, demonstrating a direct correlation between formation pressure, water conditions and hydrate growth kinetics. Stability tests conducted at 65 bar in 4 wt% NaCl solutions confirmed CO2 hydrate persistence for over 10 days, reinforcing the feasibility of hydrate-based carbon sequestration in marine settings and providing critical insights for optimizing CO2 storage in deep-sea environments
Estimating carbon storage in an old olive tree grove: A comparison of UAV, LiDAR, and manual surveys
No full textThe olive groves, particularly the old ones, represent a significant carbon sink and so they are important for climate change mitigation. Also, many of these olive groves represent an important component of the landscape heritage. This study focuses on estimating biomass and carbon content in old olive tree groves, with a specific application in a 69-year-old olive grove in central Italy. The research used UAV (Unmanned Aerial Vehicle) survey data to evaluate the geometric features of some selected olive trees, using LiDAR (Light Detection and Ranging) and manual survey as basis for comparison and benchmark. The aim was to determine the effectiveness of UAV method, which this study showed to be less costly, less time-consuming, and less prone to drawbacks compared to the LiDAR and manual measurements. After felling the olive trees, their epigeal biomass was weighed. A strong linear correlation was found between the geometric parameters (trunk circumference, crown area, and crown volume) and the fresh weight of the trees. The results of this study show that UAV surveying provides a viable solution for assessing the carbon content of old olive groves, representing a significant improvement in relation to the methods still proposed by the IPCC (Intergovernmental Panel on Climate Change). As with all other proposed methods, the main issue concerns the estimation of the belowground biomass, for which there are currently no methods with a low degree of uncertainty, so there is a need to develop more accurate models
Social network, e-democracy e "costituzionalismo digitale"
No full textL’evoluzione tecnologica rappresenta senza dubbio un inarrestabile fattore di progresso sociale: tuttavia, alcuni elementi distorsivi che la stessa introduce anche nel settore della comunicazione politica e della formazione del consenso pongono sotto stress alcune fondamentali infrastrutture del costituzionalismo. Il saggio si sofferma sull’indagine dei pregi e dei limiti della nuova democrazia digitale, con particolare riferimento al fenomeno del social networking, ed esamina possibili linee evolutive rivolte all’affermazione del tema dei diritti nella ἀγορά digitale
Hybrid Energy Storage Systems in Rail Transport
No full textAs of now, decarbonization is a central theme. In the European context, 40% of railway lines are operated by diesel trains. Among countries such as Italy, Germany or UK, even values as high as 60% are reached. In order to successfully achieve the 2030 and 2050 targets, in the past it has been considered to electrify all remaining lines. Hybrid trains, however, are an alternative to this. In this chapter, solutions for Hybrid Energy Storage Systems in rail transport will be discussed
Towards thick layer formation and mcrostructural evolution in multi-Layer friction surfacing of AA2011 alloy
No full textMulti-layer Friction Surfacing is emerging as a new solid-state Additive Manufacturing process able to build and repair materials that cannot be processed by fusion-based AM techniques. In this work, a dual approach was employed to investigate the effect of the main process parameters on the mechanical and microstructural properties of the builds. First, the influence of process parameters on the geometry of AA2011 aluminum alloy single layers was investigated through an experimental optimization campaign to assess the possibility of a thick layer formation. Second, the microstructure and mechanical properties of both the deposited material and the consumable tool after multi-layer friction surfacing were analyzed. The use of optimized parameters for the multi-layer deposition allows a thick-layer stacking, while the material behavior changes due to the substrate effect, resulting in a potential increase in the number of defects with the growth of the sample. Microstructural observations showed that the fraction of low-angle grain boundaries increases from the retreating side toward the advancing side, and from the bottom toward the top of the layer. The intensity of the pole figures and orientation distribution functions demonstrates a strain gradient throughout the layer. Although the average hardness and ultimate tensile strength of the as-built material were lower than those of the starting consumable rod, post-process heat treatment improved the hardness distribution and tensile strength up to 97 % of the AA2011-T6
Mathematical Models and Algorithms for Processing Retinal OCTA Images
No full textThis study investigates the advanced reconstruction capabilities of sampling Kantorovich (SK) operators, emphasizing their remarkable approximation properties and their application to Optical Coherence Tomography Angiography (OCTA) images from both healthy and diabetic patients. By exploiting these mathematical tools, significant enhancements in image reconstruction quality are achieved. Initially, retinal vascular network connectivity is evaluated using an algorithm that computes connected components, comparing non-reconstructed and SK-reconstructed images to demonstrate the advantages of SK-reconstruction. Moreover, SK-reconstructed superficial capillary plexus (SCP) images are analyzed to investigate the foveal avascular zone (FAZ) in both patient groups. The SK algorithm successfully identifies critical morphological differences in the FAZ between healthy and diabetic patients, highlighting the efficacy of SK operators in improving image reconstruction for diagnostic applications
Positive Patch Test Reaction to Sodium Metabisulfite: Prevalence, Relevance and Clinical Implications
No full textBackground: Sodium metabisulfite (SMB) is widely used as a preservative in topical products, injectable drugs, and food. Contact allergy to SMB is increasing but the relevance of SMB positive patch test reactions and clinical implications of SMB systemic exposure remain challenging. Objectives: To assess the prevalence and relevance of SMB positive patch test reactions and to evaluate the tolerability of a local anaesthetic solution containing SMB. Methods: A retrospective study on consecutive patch tested patients with the Italian baseline series containing SMB was performed (January 2024–April 2025). In patients who tested positive for SMB, an intradermal test with SMB and a challenge with a local anaesthetic solution containing SMB were performed. Results: Among 550 patients consecutively patch tested with the Italian baseline series, 16 tested positive for SMB (2.9% [1.8%–4.7%]). The 16 positive reactions to SMB were not considered relevant. MOAHLFA index showed a significant positive association with Age > 40 (9.67 [1.249–74.89], p = 0.03). In all 16 patients, intradermal test with SMB and local anaesthetic challenge was negative. Conclusions: A high prevalence of positive patch test reactions to SMB in the absence of relevance was observed. Moreover, a positive patch test to SMB seems not to contraindicate the administration of a local anaesthetic containing SMB