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Evaluation of Silicon-Rich Anodes for Low-Temperature Applications
No full textSilicon-rich anodes were investigated as promising alternatives to graphite for lithium-ion batteries operating at sub-zero temperatures. Micro-sized silicon particles were employed with a capacity-limitation strategy (1000 mAh g−1) to mitigate mechanical stress and volume expansion during cycling. Electrochemical performance was assessed in three-electrode half-cells and bi-layer pouch full-cells (Si - NMC811) at temperatures ranging from 25 °C down to −25 °C. Despite the increased polarization and hysteresis observed in the galvanostatic charge/discharge profiles at low temperatures, micro-Si anodes retained a reversible lithiation/delithiation behaviour and high coulombic efficiency. Full-cell response was mainly affected by the NMC cathode, while the Si anode exhibited good capacity retention. These results demonstrate that capacity-limited micro-silicon anodes enable stable and efficient operation under cold conditions, providing a scalable, safe, and cost-effective route toward next-generation lithium-ion batteries and reducing reliance on graphite now listed as a critical raw material in the E
Investigation of microfibers and microplastics in process water from spunlace nonwoven production
Get PDFMicroplastic (MP) pollution has become a pressing environmental issue due to its transfer to aquatic ecosystems through wastewater discharge, posing a growing risk to environmental sustainability. The textile industry, particularly nonwoven manufacturing, is one of the key contributors to this problem. The spunlace nonwoven process stands out in this context because of its high water demand and significant wastewater generation. Although several studies have investigated microplastics originating from textile effluents and disposable products, the contribution of the spunlace nonwoven production process, characterized by intensive water use and effluent discharge, to microplastic release has not yet been examined. Considering that spunlace fabrics are widely used in disposable Fast-Moving Consumer Goods (FMCG) such as wet wipes and hygiene products, and that their production volumes are continuously increasing, understanding the microplastic dynamics at different stages of the manufacturing process is crucial for evaluating the environmental sustainability of spunlace production. This study examines the formation and characteristics of microfibers (MFs) - including both synthetic (polyester) and cellulosic (viscose and cotton) types - in different stages of the process water used in a spunlace nonwoven production facility. Water and sludge samples were collected from the influent, effluent, and treatment stages of the process water system. The samples were pretreated with hydrogen peroxide (30% H2O2) and filtered to recover MPs and MFs. Mass- and count-based assessment and characterization analyses were performed on the particles obtained after filtration. By focusing on a previously unexamined stage of textile manufacturing, this work provides the first insights into process-related microfiber and microplastic formation in spunlace nonwoven production. The results highlight the importance of developing process and policy-level strategies to improve water reuse and wastewater management in the spunlace and nonwoven industry
Characterization of NTRM Systems for the Structural Strengthening of Masonry Cross Vaults
No full textTextile Reinforced Mortar (TRM) systems are a class of composite materials widely adopted for the structural strengthening of masonry constructions. They are usually made of inorganic matrix, which can be a lime-based or cement-based mortar, and are reinforced with layers of strengthening grids, often made of steel or glass fibres. In recent years, growing concern about sustainability has increased the interest towards materials with a lower environmental impact, by favouring the adoption of natural fibres in TRM systems. These systems are also known as Natural Textile Reinforced Mortar (NTRM). In this research, basalt-TRM composites are analysed for the structural strengthening of masonry cross vaults subjected to quasi-static shear settlement of two abutments. The mechanical characterization of the strengthening system is conducted by direct tensile tests on bare textiles and one-layer composite coupons. The durability of the strengthening system is assessed by applying an ageing protocol to both basalt textiles and composite coupons. In detail, the bare textiles were conditioned for 1000 h at 23° C in a 0.16% Ca(OH)2 alkaline solution, simulating the exposure to a lime-based-mortar aggressive environment. Meanwhile, the composite coupons were conditioned for 1000 h in water at a constant temperature of 23°. The tensile strength of conditioned samples is compared to those of the non-aged reference specimens. Then, the Finite Element (FE) simulation of a masonry cross vault is performed to assess the efficiency of the basalt-TRM strengthening system applied to the extrados, incorporating the mechanical properties of the composite material
Synergistic enhancement of PEM fuel cell performance for heavy-duty applications: PtCo/N-doped carbon catalyst and short-side-chain ionomer integration
Get PDFThis study systematically investigates a synergistic catalyst–ionomer design strategy integrating catalyst architecture, support chemistry, and ionomer structure to enable proton exchange membrane fuel cell (PEMFC) performance relevant to heavy-duty applications. A non-commercial PtCo alloy catalyst supported on nitrogen doped mesoporous carbon (PtCo/MFCS) enhances intrinsic oxygen reduction reaction activity via alloying while promoting ionomer dispersion, proton accessibility, and favorable interfacial interactions through surface nitrogen functionalities. In parallel, a short-side-chain (SSC) PFSA ionomer (Aquivion® D79) is introduced to improve proton conductivity and water retention under low-humidity conditions. In a systematic MEA campaign, PtCo/MFCS delivers over 16× higher mass activity at 0.9 V (537 vs 32 mA mgPt−1) than a commercial Pt/Vulcan catalyst, despite 43% lower Pt loading, supported by higher electrochemically active surface area and improved dispersion. Beyond kinetic gains, the mesoporous nitrogen-doped support enhances mid-to-high current density performance by facilitating oxygen transport and water management. Replacing Nafion® with Aquivion® D79 further sustains performance under partial humidification down to 33% RH, demonstrating that SSC ionomer benefits emerge only when coupled with appropriate support porosity and chemistry. Overall, the results reveal strong catalyst–support–ionomer synergy, enabling robust, balance-of plant-friendly PEMFC operation and offering a credible pathway toward DOE heavy-duty fuel cell targets
Integration of synchronised IR and PIV unsteady measurements on a channel flow
Get PDFEstimating velocity fields in wall-bounded turbulent flows using non-intrusive, wall-based measurements is a crucial challenge with significant implications for fundamental research and engineering applications like flow control. Traditional methods often rely on technically demanding intrusive probes or numerical simulations, which can be difficult to translate to real-world experimental setups. This study introduces a robust, non-intrusive experimental platform that uses infrared thermography with a heated thin-foil sensor to capture high-resolution, time-resolved measurements of unsteady heat transfer on a channel wall. These measurements are synchronized with particle image velocimetry data to enable the simultaneous acquisition of near-wall velocity fields. The methodology addresses key experimental challenges, including a low signal-to-noise ratio and the need for high-frequency acquisition. We demonstrate that the acquired heat transfer fluctuations show strong spatial and temporal coherence with near-wall structures, supporting their use for velocity field estimation. This work establishes a framework for generating reliable, synchronized datasets, paving the way for the development and validation of data-driven velocity field estimators and advanced active flow control strategies under realistic experimental conditions
Colonial Shadows: Heritage, Climate Change, and the Struggle for Resilience in Post- Colonial Africa
No full textColonial practices prioritized short-term economic gains, disrupting ecosystems and worsening climate change. These activities disrupted ecosystems, exacerbated climate change, and left lasting legacies of environmental degradation. French colonial interventions in Africa, such as Casablanca's nouvelle medina and Congo's Maison Tropicale, were framed as adapting to local climates but ultimately reinforced ecological and social inequalities. Climate change threatens local heritage and indigenous knowledge. This chapter examines the intersection of historical injustices and contemporary environmental challenges, exploring how colonial actions have shaped ongoing struggles for sustainability and equity
Robustness evaluation of existing valuable structures The case study of P.L. Nervi autogrill Motta on A4 motorway in Italy
No full textTowards optimal plasma actuator arrays for friction drag reduction
Get PDFAn optimization framework for the design of an array of DBD plasma actuators to be eventually used for friction drag reduction from turbulent flows is presented. To investigate the plasma induced flow and eventually their effect on the incoming flow, high fidelity simulations were performed. The actuators were modeled according to body force distributions well documented in the literature. The aim of the work is to explore how different geometrical and operational parameters of the PA array affect the induced flow. First, in the optimization iterations, laminar flow simulations are carried out in order to recreate a Stokes-like flow, which can compensate for the known drag-enhancing effect caused by the plasma-jets induced downwash. Then, the effect of the optimized configuration forcing is assessed on a turbulent channel flow at Reτ = 250. Eventually, also the effect of the incoming flow on the plasma-induced flow is evaluated
A methodology for boundary condition optimization in 3D-CFD of internal combustion engines
No full textThis study presents a novel computationally efficient methodology for tuning boundary conditions in 3D CFD simulations of internal combustion engines. The objective is to achieve errors below 1% for in-cylinder pressure at spark timing and below 5% for intake mass. The approach employs an iterative procedure which is grounded on thermodynamic principles, applying the laws of thermodynamics based on both numerical and experimental data during the compression phase. A multi-zone convection model is developed to optimize wall temperatures, while intake pressure is adjusted using physics-informed considerations. In order to refine the multi-zone heat transfer coefficients, the method incorporates a hybrid optimization approach that combines simulated annealing with interior point methods. The methodology is tested on a heavy-duty port fuel injection spark-ignition engine fueled by compressed natural gas. The results demonstrate the effectiveness of this methodology in improving the accuracy of CFD simulations for internal combustion engines, providing a robust framework for boundary condition optimization. This allows the number of 3D simulations required for model tuning and calibration to be reduced compared to trial-and-error or DoE approaches, enhancing model predictive capability