University of Naples Federico II
Archivio della ricerca - Università degli studi di Napoli Federico IINot a member yet
367950 research outputs found
Sort by
Perchè votare NO al Referendum costituzionale
No full textLa relazione illustra le motivazioni del NO alla Riforma costituzionale della giustizia, alla luce dei profili di rischio sul piano costituzionale
Mapping urban settlement dynamics: the case of Sri Lankans in four Italian cities
No full textThis study explores the spatio-temporal dynamics of Sri Lankan settlement in four Italian metropolitan cities – Milan, Rome, Naples, and Catania – over the period 2011-2021. Employing high‐resolution spatial grid (100×100 meters), we compute a Location Quotients (LQs) for the Sri Lankan population and examine its variation via Geographically Weighted Ridge Regression (GWRR) in each census year. Our models integrate structural, demographic, and socio‐economic dimensions to capture localised influences on ethnic concentration, while a ridge penalty mitigates multicollinearity. Diagnostic metrics (AICc, Moran’s I) confirm a generally adequate fit with moderate positive spatial autocorrelation in residuals. Results reveal clear north-south contrasts and evolving settlement patterns. Temporal comparisons indicate relative stability in Rome and Naples, contrasted by significant process of redistribution in Milan and Catania. By integrating fine‐scale spatial data with GWRR, this work advances methods for studying non‐stationary residential segregation patterns and offers insights for context‐sensitive urban policy aimed at promoting spatial integration
Solver-free artificial intelligence framework for stress-strain prediction and rapid field visualisation of fibre-reinforced polymer-confined recycled aggregate concrete
No full textAccurately predicting the stress-strain behaviour of fibre-reinforced polymer (FRP)-confined recycled aggregate concrete (FRCRAC) remains challenging due to the complex mechanics introduced by recycled aggregate. This study presents a novel two-stage machine-learning (ML) framework with a mechanics-inspired visualisation module (MIVM) to predict and visualise the stress-strain behaviour of FRCRAC. First, Optuna-optimised Categorical Boosting (CATO) models are used to predict ultimate axial strength, axial strain, and hoop strain. These predictions are then integrated into Long Short-Term Memory (LSTMO) models to construct full axial and hoop stress-strain curves, forming a CATO-LSTMO framework. Trained via ten-fold cross-validation on a combination of 194 experimental and 600 synthetic datasets, CATO-LSTMO significantly outperforms conventional analytical and hybrid models with a coefficient of determination, R2, above 98 %. Secondly, a solver-free MIVM that replicates finite element (FE) behaviour is proposed to enhance the physical interpretation of ML models. Three dedicated Categorical Boosting regressors are trained on over 350,000 nodal field outputs from Abaqus simulations to predict the three-dimensional stress, strain, and displacement distributions across 21 loading frames. These predictions are then scaled using the previously ML-generated stress-strain curves to reconstruct the frame-wise three-dimensional contour plots. The MIVM visualisations achieve results comparable to Abaqus outputs, while being about 500 times faster. This study contributes to artificial intelligence through novel hybrid ML frameworks and solver-free surrogate visualisation. The integrated CATO-LSTMO-MIVM framework is deployed as an interactive web application, and it offers practical use in engineering applications for rapidly estimating and visualising the stress-strain behaviour of FRCRAC
Porcelio e la crociata contro i Turchi nel carme 'De die mundi'
No full textAll'interno della raccolta encomiastica intitolata De felicitate temporum Pii II, il carme De die mundi costituisce un adattamento in versi del discorso pronunciato da Pio II alla dieta di Mantova (1459), in cui, com'è noto, il pontefice esortava i principi cristiani a intraprendere una crociata contro gli Ottomani dopo la caduta di Costantinopoli. L'articolo ricostruisce innanzitutto la tradizione manoscritta dell'opera di Porcelio, identificando e descrivendo i testimoni chiave, tra cui il manoscritto parzialmente autografo Vat. Lat. 1670 e l'elegante copia di dedica Reg. Lat. 1991. Offre poi un'edizione critica del De die mundi basata sul manoscritto Reg. Lat. 1991, col corredo di una traduzione italiana e di note esplicative. L'analisi mostra come Porcelio mescoli modelli classici con temi cristiani per creare un potente manifesto ideologico
Geometric rigidity for incompatible fields in the multi-well case and an application to strain-gradient plasticity
No full textWe derive a quantitative rigidity estimate for a multiwell problem in nonlinear elasticity with dislocations. Precisely, we show that the L^{1^{*}}-distance of a possibly incompatible strain field from a single well is controlled in terms of the L^{1^{*}}-distance from a finite set of wells, of curl \beta and of div \beta. As a consequence, we derive a strain-gradient plasticity model as Gamma-limit of a nonlinear finite dislocation model, containing a singular perturbation term accounting for the divergence of the strain field. This can also be seen as a generalization of the result of Alicandro et al. (2018) to the case of incompatible vector fields
Anti-inflammatory activity of walnut (Juglans regia var. Sorrento) husk extract, chemical profiling and discovery of huskol, a new ursane-type triterpenoid
No full textThe study of potential high-added-value waste materials is pivotal for their recycling and repurpose in the market. Walnut husks are a well-known source of bioactive natural products with potential applications in the antimicrobial and anticancer therapies or in the cardiovascular and neurodegenerative prevention, and as anti- inflammatory treatments. However, since the metabolic content of walnut husks is highly dependent on their variety, there is still a need for thorough systematic phytochemical investigations of this precious waste material of the food industry. Herein we report the anti-inflammatory evaluation and an NMR-based phytochemical profiling of the ethyl acetate fraction of husks obtained from Juglans regia var. Sorrento. Our study demonstrated that the extract exerts significant anti-inflammatory activity by reducing the NO (IC50 = 0.01 mg/mL) and PGE2 (IC50 = 0.007 mg/mL) production in LPS-stimulated cells in a concentration-dependent manner by inhibiting iNOS and COX-2 proteins. The phytochemical analysis of the bioactive fraction revealed the dominant presence of diarylheptanoids and triterpenoids and resulted in the discovery of the new ursane derivative huskol
Induced Drag and Vorticity in Viscous and Inviscid Flows
No full textAerodynamic drag prediction and decomposition into physical constituents is a fundamental research topic, and a clear identification of lift-induced drag in viscous and compressible flows is still an open issue. The recent vortical force theory by Wu et al., based on the Lamb vector field integration, allowed for new induced drag definitions to be proposed for viscous and compressible flows, although inconsistencies were reported in their application, with ambiguities on the physical or non-physical role of a non-zero induced drag found in two-dimensional flows. Domain variations of the drag breakdown in induced and parasite contributions also raised questions on the objective or quasi-objective nature of the two drag concepts. In this paper, classical far-field formulas, thermodynamic-based and Lamb-vector-based drag decompositions are analyzed for both inviscid and viscous flows, at low and high Reynolds number, to clearly identify the conditions for induced drag definitions to provide consistent estimates of the drag due to reversible flow phenomena. A spurious induced drag contribution is otherwise computed, resulting in negative induced drag values in two-dimensional flows. This will be shown to be related to the axial velocity perturbation, while thermodynamic methods will confirm the whole drag being of irreversible nature in all analyzed two-dimensional cases, leaving no space to any non-zero reversible drag
Structural Dispersity as a Determinant of Li-Ion Transport in Ethylene-Oxide-Based Graft Polymer Electrolytes
No full textGraft polymers with oligo(ethylene glycol) (OEG) side chains and poly(meth)acrylate backbones have been commonly studied as polymer electrolytes (PEs) owing to the ability of oligoether segments to coordinate Li+ ions. However, when poly[oligo(ethylene glycol) methyl ether methacrylate]s (P(OEG)MAs) are synthesized from commercial macromonomers, these are structurally polydisperse, as OEG segments feature a broad distribution of lengths. Herein, we investigate the influence of side-chain heterogeneity on Li-ion transport by comparing structurally polydisperse P(OEG)MAs with analogous graft polymers with homogeneous architecture, generated from discrete macromonomer feeds obtained through flash chromatography. Ionic conductivity was found to increase with increasing side-chain dispersity. For structurally polydisperse P(OEG)MAs, enhancing side-chain heterogeneity resulted in greater salt dissociation and higher ionic conductivity at relatively high salt contents. These trends are uncorrelated with differences in thermal properties, rheology, and polymer diffusivity, indicating that ion transport is not governed by overall polymer dynamics. Dispersity of side chains thus emerges as a determinant for Li-ion transport in PEs based on P(OEG)MAs. However, this effect is lost when backbone flexibility increases, i.e., when polymethacrylates are substituted with more flexible polyacrylate counterparts. By elucidating how side-chain heterogeneity and backbone flexibility affect ion transport, this work provides guidance for the rational design of graft PEs
Urban Space as a Minefield of Signs / Lo spazio urbano come miniera di segni
No full textEvery place is a minefield of signs. The external space of the city
does not consist solely of stones, bricks, concrete or steel, but also of
a multitude of elements that have to be extracted from the contextual
system in which they are immersed in order to acquire a specific
visual autonomy as the signs that they are, with their proper meaning.
These signs contribute, with the architecture taken in its entirety, from
the most significant elements such as monuments down to the most
ordinary, such as common buildings, to define and characterize the
identity of the place. Through the viewpoints offered by urban signs,
interpreting the recurring elements and their sequential arrangement,
we can read the space and visualize the constructive process as a
collective and social activity. The classification of these anonymous
signs, achieved through the comparison of elements belonging to the
same category, sets off a process of interpretation that, by placing
the individual exemplars on a plane of equivalence, eliminates any
hierarchy among the elements they represent