IRIS Università degli Studi dell'Aquila
Not a member yet
68355 research outputs found
Sort by
Sensitivity of bending stiffness to moisture content in adhesive-free wooden-doweled cross-laminated timber panels
Get PDFDespite the rapid commercial success of cross-laminated timber (CLT) in the past decade, largely thanks to its excellent thermal and structural performance, the use of synthetic adhesives still raises sustainability concerns, in particular with respect to fire behavior of the bond lines, potential VOC emissions during service, and the challenges of separating bonded layers at end-of-life for recycling or energy recovery. While wooden-doweled CLT has never been considered a viable large-scale alternative to traditional CLT, it is important to better understand the properties of adhesive-free CLT panels as potential surrogates. In the case of wooden-doweled CLT, the mechanical integrity of the panel depends on the assembly conditions, where the moisture content of the dowels at insertion is lower than that of the timber boards. The swelling of the dowels, as they equilibrate with the moisture content of the surrounding timber, ensures the structural performance of the panel. However, what happens if there is a general decrease in moisture content over the building's lifespan and the differential shrinkage between the boards and dowels compromises the structural integrity? In this study, the authors tested adhesive-free wooden-doweled CLT panels, assessing the sensitivity of the bending stiffness to three moisture content scenarios: 8, 12 and 15%. Using classical methods for predicting the stiffness of layered beams, such as the γ and the shear analogy methods, the authors indirectly estimated the slip modulus based on three-point bending tests and modal parameters as a function of wood moisture content. Thus, the paper, examining the mechanical behavior of wooden-doweled CLT panels under varying moisture content conditions, provides practical recommendations for their use
Direct liquid cooling in compact machines: Advantages and limitations
Get PDFThe increasing demand for more efficient propulsion systems in electric and hybrid vehicles necessitates advanced thermal management in compact electric machines. This study investigates a novel direct liquid cooling (DLC) approach using Litz copper wires braided around a stainless steel tube to enhance heat removal. Analytical model, numerical simulations, and experimental testing were employed to evaluate the system's cooling efficiency, considering various conductor sizes and supply currents. The results show that direct liquid cooling significantly lowers winding temperatures compared to traditional cooling methods when operating at the same load. These temperature dependencies are explored in more detail in the paper using the developed analytical approach. The analytical model, which was verified with experimental results, also indicates that direct liquid cooling windings can support up to 277% more current than traditional water jacket-cooled windings while maintaining a maximum temperature of 70 °C. These findings demonstrate that direct liquid cooling windings are a highly effective method for enhancing thermal performance even in compact motors, enabling higher power densities
Genetic characterization of the endocannabinoid system and psychiatric features in patients with migraine and medication overuse headache
Get PDFAnalysis of Communication and Control Performance of Multi-Hop IEEE 802.15.4-based WNCSs under Wi-Fi Interference
No full textThis paper investigates a co-design framework for wireless networked control systems (WNCSs) that integrates multi-hop IEEE 802.15.4-based links under Wi-Fi interference, addressing the challenges of signal-to-interference-plus-noise ratio (SINR) degradation in adverse industrial environments. Multihop configurations are essential for extending the operational range and improving SINR in harsh propagation conditions, but they introduce trade-offs in control stability, latency, and computational complexity. We investigate the impact of multi-hop communication on system performance, comparing Bernoulli and Markovian control strategies. Our results demonstrate that multihop links effectively extend the operational range and mitigate SINR degradation, but at the cost of increased latency and computational cost. We analyze the spectral radius of the system stability verification matrix and control costs for Bernoulli and Markovian control strategies, illustrating that network latency and hop counts can be balanced while maintaining the stability of the multi-hop WNCS. Markovian strategy, although more computationally intensive, outperforms Bernoulli strategy under high interference, offering a robust solution for industrial WNCSs. The proposed framework provides a practical approach for deploying reliable WNCSs in interference-prone environments
Modeling the Black and Brown Carbon Absorption and Their Radiative Impact: The June 2023 Intense Canadian Boreal Wildfires Case Study
Get PDFBlack carbon (BC) and brown carbon (BrC) are light-absorbing aerosols with significant climate impacts, but their absorption properties and direct radiative effect (DRE) remain uncertain. We simulated BC and BrC absorption during the intense Canadian boreal wildfires in June 2023 using an enhanced version of CHIMERE chemical and transport model. The study focused on a domain extending from North America to Eastern Europe, including the Arctic up to 85°N. The enhanced model includes an update treatment for BC absorption enhancement and a BrC aging scheme accounting for browning and blanching through oxidation. Validation against Aerosol Robotic Network and satellite data showed the model accurately reproduced aerosol optical depth (AOD) at multiple wavelengths, both near wildfire sources and during transoceanic transport to Europe. Improvements were observed in simulations of absorbing AOD (absorbing aerosol optical) compared with the baseline model. Significant enhancements were achieved in capturing the spatial distribution of aerosol absorption in areas affected by wildfire emissions. For June 2023, the regional all-sky DRE attributed to Canadian wildfires was reduced from −2.1 W/m2 in the control model to −1.9 W/m2 in the enhanced model. This corresponded to an additional warming effect of +0.2 W/m2 (+10%) due to the advanced treatment of BC and BrC absorption. These results indicate the importance of accurate aerosol absorption modeling in regional climate predictions, during large-scale biomass burning events. They also highlight potential overestimations of cooling effects in traditional models, emphasizing the need of improved aerosol parameterization to better simulate the DRE and for evaluating the impacts of mitigation strategies
Enhancing IIoT Security: BERT-Driven Intrusion Detection with MLP in Industrial Networks
No full textIntrusion Detection Systems (IDS) are pivotal in securing Industrial Internet of Things (IIoT) networks, where the convergence of operational technology (OT) and information technology (IT) has heightened vulnerability to sophisticated cyber threats. The complexity, scale, and heterogeneity of IIoT environments necessitate advanced threat detection mechanisms capable of identifying and mitigating attacks in real-time. In this study, we propose a novel deep learning-based IDS framework that integrates Google BERT for advanced feature extraction and a Multi-Layer Perceptron (MLP) for robust classification. Our methodology is evaluated using three IIoT-specific benchmark datasets: CIC APT IIoT 2024, WUSTL IIoT 2021, and WUSTL IIoT 2018, which encompass diverse attack scenarios and network behaviors. To address the prevalent issue of class imbalance in these datasets, we employ the Synthetic Minority Over-sampling Technique (SMOTE), enhancing the model’s ability to learn and generalize minority attack patterns effectively. Experimental results demonstrate that our proposed framework significantly improves the detection accuracy of cyber threats in IIoT environments. The system’s scalability, efficiency, and real-time applicability make it a promising solution for safeguarding OT networks against evolving cyber threats. This study provides a practical and high-performance approach to enhancing the resilience of IIoT ecosystems
On Regional Sampled-Data Control of Nonlinear Time-Delay Systems with Input Saturation Constraints
Get PDFIn this paper, we deal with the stabilization problem of nonlinear time-delay systems affected by input saturation constraints via sampled-data dynamic output feedback controllers. Nonlinear time-delay systems not necessarily affine in the control input are studied. A new approach for the design of sampled-data dynamic output feedback controllers is provided taking into account the effects of input saturation constraints. In particular, it is shown that the digital implementation via suitable approximation functions of dynamic output steepest descent feedback (continuous or not) with amplitude bounds yields the practical stability, with arbitrarily small final target ball, of the related sampled-data closed-loop system limited to suitably small regions. The case of time-varying sampling intervals and the stability analysis of the inter-sampling system behavior are included in the theory here developed. The provided results can be applied also for nonlinear delay-free systems which are here addressed as a special case. An example is presented which validates the theoretical results
Saperi commerciali da Oriente a Occidente
No full textIl Medioevo fu un periodo primitivo, pericoloso e soprattutto arretrato? Oppure una delle sue caratteristiche fu proprio quella di saper ripensare i modelli che provenivano dal passato? È il caso, per esempio, delle città e delle campagne italiane: fra X e XIV secolo, in una fase di intensa crescita in ogni ambito, gran parte delle strutture cittadine e dell’organizzazione del paesaggio venne decisamente riplasmata. Se poi volgiamo lo sguardo al mondo economico, scopriamo che molti degli strumenti finanziari che adoperiamo quotidianamente furono immaginati allora, assieme alle forme di organizzazione del lavoro e aziendale che ci sono familiari. Lo stesso possiamo dire di alcuni fenomeni culturali: da una certa idea della figura femminile al ruolo dell’arte come strumento educativo, di cui fatichiamo a vedere e a valutare la ‘storicità’.
Il Medioevo dei secoli qui considerati, dunque, fu soprattutto un’età creativa, caratterizzata da innovazioni, sperimentazioni e invenzioni a tutto campo e questo libro ne restituisce un’immagine per molti aspetti diversa e sorprendente. Lo fagrazie all’apporto dei maggiori esponenti della medievistica italiana e internazionale, in un’opera di grande impatto e originalità
Reforming Italy’s long-term care system: the role of barriers to and drivers of the use of services at the local level
Get PDFBackground: In Italy, population ageing is causing an unprecedented demand for long-term care (LTC) services, that led to the recent national reform of the LTC system (Law n. 33/2023). Since LTC services are provided by regional authorities, identifying drivers of and barriers to their use by older people and their family caregivers locally is very important to identify the mismatch between national regulation and local demand of these services. Methods: To this purpose, in 2019-2020, 450 family caregiver (FC)-older care recipient (OCR) dyads from 13 healthcare districts of the Marche region (Central Italy) were surveyed. A Two-step Bayesian Multiclass procedure was used for the analysis. The main drivers of the use of healthcare services are FC’s age and gender (being a man), and OCR’s age and level of disability. Results: The main barrier to the use of private services is their cost, while for the public ones is their unavailability. The most common private service is represented by migrant care workers (MCWs), hired privately by the older people’s families. Conclusion: Findings suggest that the recent national LTC reform in Italy does not seem to have fully captured the LTC needs of older people, and some policy suggestions are therefore provided in this regard