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On-Board Integration of Hybrid Energy Storage Systems in Heavy Duty Vehicles: The Electric Buses Use Case
No full textRoad transportation contributes to 79% of the total transport emissions. To achieve European emissions targets by 2050, a sustainable mobility based on electric vehicles (EVs) powered by batteries or fuel cells is required. Albeit Li-ion batteries represent the best choice for light duty EVs, green transition for heavy duty transport is more challenging because of the greater mileage and the lack of fast-charging infrastructure. To extend mileage range and energy storage lifespan, hybridization of different energy storage technologies represents a promising solution towards a green transition based on zero-emissions heavy duty vehicles. In this Chapter, different systems are presented for a bus application. Three innovative hybrid propulsion systems, consisting of: (i) LiFePO4 battery (LFP)/Proton Exchange Membrane Fuel Cell (PEMFC), (ii) LFP/Vanadium Redox Flow Battery (VRFB) and (iii) Ni–NaCl battery coupled with PEMFC are analysed with reference to a real case study (i.e., urban electric bus) and compared to an electric bus powered by only LFP. With respect to the case study, it is demonstrated that there are benefits of hybridization in terms of mileage range and battery lifespan extension (when LFP is considered), paving the way for an efficient and effective green transition
Efficient Cross-Chain Smart Contract Execution via State Channels
No full textPublic blockchains offer transparency and security guarantees, but suffer from limited throughput, high latency, and unpredictable transaction costs, making them unsuitable for the high-frequency data flows of the Internet of Things. In this work, we address these scalability challenges by introducing a hybrid architecture that leverages state channels to enable efficient cross-chain smart contract execution between a permissioned ledger, responsible for capturing pollutant measurements from IoT sensors, and a public blockchain, used for final settlement. Our approach enables the processing of sensor readings to be performed off-chain in a lightweight, low-cost environment, while preserving the integrity and non-repudiation guarantees of on-chain settlement through a state channel. We describe the protocol design in detail, and the use of our solution in a case study involving water quality sensors
Developing a learner dictionary of collocations: description and evaluation of a multi-method approach
No full textThis study describes and evaluates a multi-method approach for identifying and extracting collocations to develop a learner Italian collocation dictionary.
The approach integrates part-of-speech tagging and dependency parsing to extract six syntactic relations from a reference corpus of Italian.
The initial set of candidates was gradually reduced using frequency, dispersion, and association measures.
This set was then evaluated by comparing it with existing collocation dictionaries and gathering expert judgments on which collocations should be included.
Combining these two evaluations, further refined the list.
Moreover, the effect of statistical measures on expert judgments was investigated.
Results revealed that dispersion and association measures positively influenced human evaluations, while higher frequency often correlated with negative ratings.
This triangulation of corpus-based and statistical methods, human judgements and comparison with existing dictionaries captures collocations widely used across genres, suitable for inclusion in a learner dictionary, offering a useful tool for learners while contributing to corpusbased collocation research
Modeling of ammonia under-expanded jets for application in advanced propulsion systems
No full textThe adoption of ammonia as a fuel is gaining significance in various applications, including propulsion systems, gas turbines, and burners. In particular, the combustion of liquid ammonia presents an attractive option due to its low cost and its capacity to reduce local temperatures, thereby limiting thermal NOx emissions. In this context, investigating ammonia injection processes is relevant for optimizing and improving ammonia-fueled combustion systems. Thus, this work presents a combined experimental and numerical analysis of ammonia jets for applications in advanced propulsion systems, where the multiphase flow resulting from ammonia injection was investigated using a purposely developed CFD code characterized by low numerical dissipation and the adoption of real-fluid properties. The simulation methodology is validated against experiments performed at the Université d’Orléans, including optical measurements based on Schlieren and Diffuse Back-Illumination (DBI) extinction techniques, as well as local temperature measurements. This study provides insights into jet morphology and offers a quantitative assessment of parameters — including liquid penetration and local temperature — that are crucial for advancing the design of ammonia combustion systems. The outcomes offer an enhanced representation of jet structure, highlighting the presence of under-expanded jets and Mach discs when ammonia is injected at high pressures. They also demonstrate that under-expanded shock structures are strongly dependent on the temperature of liquid fuel injection
Fatigue softening mechanisms in UFG-EUROFER97 steel. A microstructural study
No full textA novel Thermo-Mechanical Treatment (TMT) developed by us leads to a microstructure with Ultra-Fine Grains (UFG) resulting in improved mechanical properties compared to those of standard EUROFER97 steel, foreseen for nuclear fusion applications. Since softening was observed after High Cycle Fatigue (HCF) tests at room temperature, this work investigated the specific microstructural mechanisms. The microstructure evolution of fatigued samples has been studied by means of Electron Back-Scattered Diffraction (EBSD), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Softening resulted to be originated by the phenomenon of fatigue-assisted grain coarsening. HCF always leads to the increase of grain and sub-grain size together with texture change, and such modifications depend on the stress level. Under cyclic stress, boundary migration and absorption in the boundaries of dislocations produced by Frank-Read sources inside the grains lead to an excess of dislocations in the boundaries. Although the stability and mobility of High-Angle Grain Boundaries (HAGBs) and Low-Angle Grain Boundaries (LAGBs) are totally different, both the boundaries become unstable. In the final step of the process, the collapse or sliding of unstable HAGBs and LAGBs give rise to a population of grains and sub-grains of larger size. The novel TMT demonstrates improved softening behavior compared to standard EUROFER97, and the results obtained will guide future research toward further improvements
Existence of optimal periodic strategies in a model with nonlocal spatiotemporal dispersal
No full textIn this paper, we investigate a control problem for a nonlinear integro-difffferential system incorporating both spatial and temporal nonlocal terms, subject to periodic condition in time. The equation, derived from population dynamics, describes the evolution of population density under growth, migration, and memory effects. The control set is feedback-based and spatially nonlocal, depending on a weighted integral of the state. We establish the existence of controlled trajectories that approximate the infimum or supremum of a cost functional with arbitrary precision. Moreover, under additional regularity assumptions on the bounding functions of the control set, we provide the existence of truly optimal controlled trajectories. The analysis employs topological methods in nonlinear analysis and tailored techniques to address temporal nonlocalities
Towards systematic random process representation: Bimodal PSDs characterized by bandwidth indices
No full textSpectral approaches based on power spectral density (PSD) analysis are widely used for fatigue assessment of flexible structures due to their computational efficiency and statistical reliability. However, their accuracy depends on representative PSD datasets, which are often defined arbitrarily and fail to capture the diversity of real response shapes. This study introduces a systematic methodology to generate a minimal yet representative set of PSDs for vibration fatigue analysis. The approach models PSDs using simple rectangular bimodal shapes, described by three independent parameters and directly linked to classical bandwidth indices. This formulation provides a compact representation of structural responses while ensuring equivalence in fatigue damage rather than frequency content. Validation against sample stress PSDs from finite element models demonstrates that the bimodal approximation reproduces both cycle amplitude distributions and damage potentials with consistency comparable to established spectral methods. The proposed framework enables a more robust definition of representative load cases and supports the development and evaluation of fatigue assessment tools under realistic conditions
L’EMPATIA FENOMENOLOGICADI EDITH STEIN.UNA PROPOSTA APPLICATIVANEI CONTESTI EDUCATIVI
No full textThe aim of this paperis to highlight some possible applications of Steinian empathy in edu-cation. Starting from “becoming aware”of the original core through empathic experience, we will try to demonstrate how trainees can be guided by the trainer towards learning a particular form of listening –which we will call “suspensive”–and towards an awareness of the interrelatedness that links each core to the other. In this experience of the other that leads back to the Self, we will finally see as a further application of Steinian empathy the possibility of self-training as a work of social trainingwhere each individual, although different from every other, has equal rights to the expression and realisation of their partic-ular embodied personalit