The performance and hydrodynamics of a Hybrid Wave Energy Converter (HWEC) device, combining Oscillating Water Column (OWC) and Overtopping Wave Energy Converter (OWEC) technologies, inserted into a 2:3 sloped breakwater, are investigated. HWEC and individual OWC and OWEC, subject to the action of incident regular waves with periods from 6 to 14 s and wave heights of 1, 2, and 3 m, are studied and compared. Investigations are carried out by using the ANSYS-FLUENT (R) software and adopting a numerical model based on the Reynolds-Averaged Navier-Stokes equations, the Volume of Fluid method for the free surface flow, and a hybrid kappa-omega SST turbulent/laminar model to deal with the involved complex phenomena. The HWEC device has higher efficiency than the individual OWC and OWEC devices and a more constant efficiency over the wave period interval, showing that both OWC and OWEC technologies complement each other and work well together. The maximum efficiency is achieved at the resonance period, around 9 s, reaching 77.6, 76.9, and 75.5% for incident wave heights of 1, 2, and 3 m, respectively. The energy balance analysis highlights that the HWEC device provides the best efficiency due to the limitation of the reflected wave energy and energy losses.
Fire accidents in road tunnels can cause a significant number of fatalities and severe damage to tunnel structures. The tunnel European directive applies to the trans-European road network and requires the use of active smoke control systems in most tunnels longer than 1000 m. Research has investigated whether shorter tunnels without active smoke control systems are safe. If smoke contaminates the lower layer where people evacuate, it can impair visibility. This disturbs egress and may cause intoxication and, eventually, death. The FireFoam computer code was applied to the Memorial Tunnel fire ventilation tests for validation. This work investigates the effect of varying the heat release rate (HRR), ranging from 6 to 100 MW, under a wind velocity of 0.77 m/s and in the absence of wind. Results show that high HRR moves the start of lower layer smoke contamination closer to the fire source, reducing the distance from 390 m at 14 MW to as close as 210 m at 100 MW. An analytical model was developed to predict the distance from the fire source where smoke can contaminate the lower layer and was subsequently improved to account for HRR variation.
This study investigates the effective stiffness of non-planar reinforced concrete walls, a key parameter in seismic design. By assembling a database of experimental cyclic tests, it highlights how effective stiffness varies with wall geometry, loading direction, and axial load ratio and eccentricity - factors often neglected in current code formulations. Using pushover analyses with a simplified beam-truss model (BTM), the study demonstrates good agreement with experimental data and supports BTM use for estimating effective stiffness. The findings underscore the need to revise effective stiffness definitions in design codes and promote further research for better seismic design of non-planar walls.
Managed aquifer recharge (MAR) provides a nature-based solution to water scarcity issues, contributing to the design of effective water management policies. The novelty of this study lies in the integration of multivariate statistical methods within the framework of multicriteria decision analysis to provide nonsubjective, semiautomatic estimations of MAR feasibility based on three thematic layers, particularly intrinsic (hydro-geological, topographical, meteorological) features, water availability and demand for MAR. The concept of MAR typology is used to define the MAR problem and select a set of criteria for each thematic layer that are relevant for the Sado River Basin (southern Portugal). The hierarchical clustering algorithm (HCA) is used to partition the study area into distinct subregions based on selected criteria. For each subregion and thematic layer, a set of weight coefficients for the criteria is generated via products of the cumulative variance of the principal scores with the corresponding eigenvector matrix, which are then used to generate multiple realizations of the thematic maps. The results reveal that the majority of the study area (60%) has mean feasibility scores less than 0.54, whereas the remaining 40% (highest values) vary within a smaller interval (0.54-0.67). The present results are consistent with the previous study, with both identifying the same high-suitability regions. Additionally, it allows exploration of the variability in criteria weights across multiple realizations, providing a preliminary indication of how this variability can influence the results. This approach can easily be implemented in software and ultimately automated, supporting the unsupervised streamlining of the decision-making process.
Although urban resilience is a complex concept, several initiatives have made it more tangible. Urban public authorities and policymakers are of utmost importance, as they influence multiple neighbourhoods, stakeholders and aspects of urban resilience. Nevertheless, the role of individual facilities—such as sports fields—should not be overlooked. While their impacts are smaller in scale, they can significantly enhance local resilience and serve as inspirational pilots for broader initiatives. To assess resilience at the facility scale, an existing assessment framework was adapted, aligned with ESG (environmental, social and governance) criteria and climate action pillars and valuing ecosystem services. In the sports field case study, stormwater was reframed from a burden into a resource and integrated with other scheduled resilience-enhancing interventions: water conservation, installation of photovoltaic panels, enhanced tree shading, and circularity through sports equipment reuse. Together, these interventions strengthen urban sustainability, resilience, and climate adaptation while delivering ecological and social benefits. The stormwater drainage system was modelled to simulate naturalization actions. The assessment framework is described, and its application at both neighbourhood and facility scales is discussed. Comparisons between the existing and improved situations show clear resilience gains, and opportunities for extending these measures to the city scale are explored.
