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Simple formulas for the dynamic response of parametrically excited slender and straight structures immersed in fluid
No full textThis work presents the development of a simplified mathematical formulation for the fast evaluation of the steady state response of slender structures under parametric excitation, considering also the interaction with a still surrounding fluid. The simplified formulation is obtained from a previous solution based on the multiple scales method. However, this previous solution requires a series of cumbersome integrals to be evaluated, rendering it non-attractive for widespread use in engineering design. The objective of the simplified solution is then to render it attractive as a design aiding tool for structural engineers. Along the work, many examples are shown comparing the proposed formulation with solutions obtained with the Finite Element Method in order to address the capability of the latter to correctly predict the amplitude of response of the structure. The results presented highlight this capability, and also provide a guided approach on how the formulation can be used for parametric investigations of the structure at hand
Evaluation of “Hot Spots” for Pedestrian Risk Assessment and Mitigation in Flood Prone Historic Built Environments
No full textPedestrian safety in flood-prone built environments is a significant challenge, especially when extreme events occur in areas without effective structural measures. Historic Built Environments (HBEs) are critical scenarios due to their complex layouts, high tourist presence, and limited risk-mitigation strategies. This work proposes a simulation-based approach to support decision-makers for effective evacuation planning towards the identification of HBE “hot spots” in emergency scenarios and the definition of suitable mitigation strategies for pedestrians, such as deployment of safety devices, street furniture, and risk/wayfinding signage. A parametric HBE scenario, featuring a river and a grid-like street network, is employed to simulate evacuation dynamics under consolidated environmental conditions (i.e. hydrodynamic effects) and pedestrian behaviors (i.e., pursuing the optimal evacuation strategy). Usage patterns provide information on “hot spot” requiring safety interventions based on critical floodwater-pedestrian interactions, as well as on the pedestrian individual vulnerability depending on age. Findings highlight that streets parallel to the river flow are more suitable to host shelters, as they benefit from building screening, while crossroads and street perpendicular to the river flow are priority areas for installing urban furniture and signage to improve pedestrian stability and wayfinding/decision-making. Furthermore, large squares could be equipped with raised platforms and sidewalks allowing pedestrian practicability, given the potential for high water depths in case of extreme events. This approach advances current methodologies by linking pedestrian dynamics with mapping floodwater hazard and users’ vulnerability, providing insights at the HBE open spaces scale, and a comprehensive framework for improving resilience in safer, more adaptive HBEs
Healthcare Associated infections: European comparative analysis and forensic expertise in compensation systems
No full textBackground/Objectives. Healthcare-associated infections (HAIs) represent one of the most common and serious complications of healthcare, significantly impacting both clinical outcomes and medicolegal processes. The rising incidence of HAIs has led to increased attention toward compensation mechanisms. In Europe, there are various compensation systems for personal injury, and HAIs can also be considered in the calculation of redressable biological damage. Methods. This study provides a comparative analysis of compensation systems in selected European countries, focusing specifically on the treatment of HAIs. All studies published between 2013 and 2023 on HAIs and compensation systems have been accounted for, yielding 296 relevant articles, of which 21 met the inclusion criteria. Further literature, data, and additional records were identified through hand searching. Results. The aim of this review is to explore the most effective compensation systems for HAIs and to emphasize the critical role of forensic expertise in these processes. Notably, no-fault compensation systems emerged as more efficient and cost-effective, offering faster resolution times compared to fault-based models. Conclusions. In all systems, forensic medical experts play an essential role in assessing cases and determining appropriate compensation
Mode Shape Reconstruction Using Operational Modal Analysis of Stay Cables Load Cells Data
No full textThis paper shows the possibility of using load cells on stay cables for monitoring the modal properties of cable-stayed bridges. This strategy allows reducing the number of sensors to be placed on the infrastructure to develop a comprehensive structural health monitoring system since load cells substitute the use of accelerometers over the deck. The use of load cells measuring with a high sampling frequency has a twofold purpose: (i) to monitor the axial force on cables and (ii) to identify the deck modal properties by using operational modal analysis techniques. The work is developed by considering as case study a newly built cable-stayed bridge located in Central Italy. The bridge has been equipped with a complete static and dynamic monitoring system and measures of about 2-year period are used to assess the feasibility of the proposed strategy. The dynamics of the deck identified by using load cell recordings is compared with that identified through accelerometers installed over the deck, as well as with results of a comprehensive operational modal analysis performed during the proof load test of the bridge. Results are promising, demonstrating the potential of the proposed strategy
Assessing residential biomass combustion emissions in the Marche Region, Italy, through a high-resolution bottom-up methodology
No full textThe estimation of airborne pollutant emissions caused by residential biomass combustion is a critical challenge in regional air quality assessment, especially due to the lack of accurate data on fuel consumption and the common use of biomass outside official markets. National inventories often adopt a top-down approach based on aggregated statistical sources and generalized emission factors, which may not reflect real consumption patterns and combustion technologies at the local level. This study compares a top-down methodology with a bottom-up approach developed specifically for the Marche Region (Italy), aiming to build a more accurate regional emission inventory. The bottom-up method is based on a 2023 household survey involving over 9,700 respondents, of whom 31% reported using biomass for heating. Where statistically reliable, data were used to generate municipality-level estimates; otherwise, emissions were calculated for grouped municipalities with similar geographic, climatic (heating degree days), and administrative characteristics. Technology-specific emission factors (Tier 2) from the EMEP/EEA guidebook were applied. The results show significantly higher biomass consumption and associated emissions – especially PM10, PM2.5 and NOx – compared to national and regional inventories based on top-down assumptions. This work highlights the added value of locally grounded bottom-up data in improving the spatial and quantitative accuracy of regional emission inventories and supports the adoption of hybrid or revised national approaches that better capture realworld dynamics
Quantum CSS LDPC Codes with Quasi-Dyadic Structure
Get PDFQuantum quasi-cyclic (QC) and quantum low-density parity-check (LDPC) codes have received significant attention due to their algebraic regularity and performance under low-complexity decoding. In this work, we explore a class of structured quantum codes based on reproducible matrices, which generalize known families such as cyclic, QC, and dyadic codes. Focusing on sparse quasi-dyadic (QD) structures, we investigate how their symmetries influence Tanner graph cycles. Moreover, we construct quantum LDPC codes within the Calderbank-Shor-Steane (CSS) framework, analyzing dual-containing configurations, and assess their error rates
State of the art of concrete bridge deck waterproofing in Italy: analysis and insights from survey-based data
No full textConcrete bridge waterproofing is a crucial aspect of infrastructure durability, especially in regions with varying climatic conditions and with the presence of chloride due to the seaside. Protecting structures from water infiltration prevents damage, thereby extending their service life and reducing maintenance costs. The waterproofing market today offers a full range of solutions, making it difficult to choose the most appropriate product. This paper presents the analysis of the results of a survey that involved construction companies, public agencies, and organisations in the infrastructure sector operating in motorways, state roads, and provincial roads, equally distributed between North, Central, and South of Italy. The aim is to assess the state of the art of concrete bridge deck waterproofing in Italy. This pilot survey is the preliminary cognitive phase of a larger European Union-funded project (Next Generation EU): Waterproofing Innovations for Concrete Decks (WInCoDe). The findings provide insights into the most employed waterproofing systems in new and existing concrete bridge decks, their selection criteria, the operations carried out during their installation, their effectiveness, and observed weaknesses. Moreover, the study explores emerging trends and potential areas for innovation. This research contributes to enhancing knowledge for improving waterproofing practices and ensuring long-term infrastructure resilience and sustainability
Modal Identification of Buildings with Complex Geometry and Tested at Different Times
No full textBuildings with complex geometries often present challenges in dynamic identification due to the presence of numerous vibration modes, some of which are closely spaced and difficult to clearly identify. These modes can be hard to differentiate during modal testing, which can create complications when tests are performed at different times. This study addresses the challenges encountered in the dynamic identification of a complex hospital building using operational modal analysis. The building consists of several structural bodies of the same height and structural typology, built adjacent to each other, resulting in a complex floor plan geometry. Additionally, the entire structure underwent seismic retrofitting, with the once separate bodies now interconnected by steel elements and dissipative devices. The issues in the comprehensive dynamic identification are addressed, and a procedure for the definition of a reference sensor configuration for ambient vibration tests on such buildings is proposed
Electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism
Get PDFLight propagation through artificially patterned anisotropic materials, such as dielectric metasurfaces, enables precise control of the spatio-vectorial properties of optical fields using highly transparent, thin, and flat optical elements. Liquid-crystal cells are a common realization of such devices. Optical losses are typically assumed to be polarization-independent and are therefore often overlooked in modeling these systems. In this work, we introduce electrically tunable liquid-crystal metasurfaces with patterned birefringence and dichroism, achieved by incorporating dichroic dye molecules into the liquid-crystal mixture. These dye molecules align with the liquid crystal, effectively coupling birefringence and dichroism effects. The behavior of these metasurfaces is described using non-unitary Jones matrices, validated through polarimetric measurements. In the case of devices that are patterned to form polarization gratings, we also characterize the diffraction efficiency as a function of the dichroism and birefringence parameters, which can be tuned jointly by applying an electric field across the cell. This study not only introduces a new class of optical components but also deepens our understanding of light propagation through anisotropic materials, where dichroism can naturally arise from bulk material properties or from reflection and transmission laws at their interfaces
