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Structural Integrity Evaluation of Three-Dimensional-Printed Graphene-Reinforced Polylactic Acid Notched Plates Using Failure Assessment Diagrams
No full textPublisher Copyright: Copyright © 2025 by ASME.Failure assessment diagrams (FADs) constitute a well-known structural integrity evaluation tool that allows structural components containing crack-like defects to be assessed through a simultaneous analysis of fracture and plastic-collapse processes. FADs are included in the most recognized structural integrity assessment procedures/standards, such as BS7910 and API 579/ASME FFS-1, and their use is generally limited to metallic components containing crack-like defects. On the other hand, structural responsibilities are being assumed by three-dimensional-printed composites, and particularly by those obtained through FFF (fused filament fabrication), beyond their most extended use as prototyping materials. The resulting structural components may contain notch-type defects (e.g., grooves, corners, holes) that determine their corresponding structural integrity. Thus, it is necessary to define structural integrity assessment criteria for this kind of materials when containing any kind of stress risers, beyond crack-like defects. This work justifies the use of BS7910 Level 1 FAD, coupled with a notch correction derived from the theory of critical distances (TCD), to analyze graphene-reinforced polylactic acid (PLA) plates subjected to pure tensile loading conditions and containing U- and V-notches. The results reveal that, for U- and V-notches, the assessment points representing the plates at failure are located within the FAD area corresponding to unsafe conditions, providing conservative evaluations with moderate safety margins. For plates containing circular holes, the proposed approach provides unsafe predictions.Peer reviewe
Privacy-preserving computation meets quantum computing: A scoping review
Get PDFPublisher Copyright: © 2025 Chongqing University of Posts and Telecommunications.Privacy-Preserving Computation (PPC) comprises the techniques, schemes and protocols which ensure privacy and confidentiality in the context of secure computation and data analysis. Most of the current PPC techniques rely on the complexity of cryptographic operations, which are expected to be efficiently solved by quantum computers soon. This review explores how PPC can be built on top of quantum computing itself to alleviate these future threats. We analyze quantum proposals for Secure Multi-party Computation, Oblivious Transfer and Homomorphic Encryption from the last decade focusing on their maturity and the challenges they currently face. Our findings show a strong focus on purely theoretical works, but a rise on the experimental consideration of these techniques in the last 5 years. The applicability of these techniques to actual use cases is an underexplored aspect which could lead to the practical assessment of these techniques.Peer reviewe
Transmissivity of solar radiation and the influence of diffuse radiation in different trees inside a tropical urban park
No full textPublisher Copyright: © 2025 Elsevier B.V.Trees are known to have a positive effect on the thermal environment of urban areas. However, different species have different impact in the local climate. In this work we present the results of a measurement campaign aiming to quantify the effect of different leaf structures on the solar transmissivity and the impact on mean radiant temperature as a relevant variable for thermal comfort. Six different trees have been assessed on different weather conditions. Sensors were deployed to measure air temperature, wind speed and direction, relative humidity, globe temperature and solar radiation (global and diffuse). Each day two trees were evaluated simultaneously with sensors under the tree crown and beside it (as a climatic reference site). The quantitative results show that the transmissivity of solar radiation through the tree's crown (varying between 9.4 % and 30.1 %) was influenced by the leaf structure and the sky view factor. Based on these, the impact of the direct and diffuse components of solar radiation on the tree transmissivity was different. A higher fraction of incoming diffuse radiation increased the transmissivity of solar radiation, especially for trees with low leaf area Index and high sky view factor. Overall, lower solar transmissivity, higher levels of incoming solar radiation and lower fraction of diffuse radiation caused a higher impact on mean radiant temperature under the tree crown, reaching a reduction of 27.0 °C. The outcomes of this work can influence decision-making in the context of improving thermal comfort through adequate management of greenery.Peer reviewe
Sea surface temperature impacts on tropical urban environment: A WRF modelling investigation
No full textPublisher Copyright: © 2025 The Author(s)In recent times urban planners in dense cities have realized the negative impact of the urban heat island (UHI) phenomenon and its strong relation with climate change. Sea Surface Temperature (SST) significantly impacts the coastal urban environment, and a systematic error may adversely impact an urban thermal assessment. This study examines the role of SST during representative months in Singapore. It is found that the reanalysis SST synthesized with satellite SST indicates an improvement in RMSE up to 0.9 °C across representative seasons at station locations within the urban canopy. The systematic SST error leads to a variation in estimated UHI intensity by up to 0.3 °C, demonstrating its non-negligible impact. The highest spatial mean UHI intensity (2.9 °C) occurs at midnight in October while the lowest UHI (1.4 °C) occurs in February. The influence of sea breezes (under weak synoptic patterns in the Inter-Monsoon seasons) is analyzed to show relevant impact in the area close to the coastline. The results provide insights into the potential future impact of global warming and rising SST on Singapore's thermal environment. Adequate urban planning can promote ventilation paths starting in the coastline to further remove urban heat in inland locations.Peer reviewe
Thermodynamics-guided high-throughput discovery of magnetic high-entropy alloys fabricated by spark plasma sintering at different temperatures
Get PDFPublisher Copyright: © 2025 The AuthorsThis study presents a high-throughput, thermodynamics-guided framework for the discovery of novel magnetic high-entropy alloys (HEA). High-throughput CALPHAD simulations were employed to predict the equilibrium phases and Curie temperatures across a broad compositional space, including benchmark systems. The computational results were integrated with statistical data analysis to identify candidate compositions with optimal magnetic properties. The selected Fe42Co17Ni12Al17Cu6Ti6 HEA was fabricated by spark plasma sintering at various temperatures. For direct comparison, a reference Alnico 5 alloy was synthesized under the same processing conditions at 1273 K. The as-sintered HEA exhibited superior magnetic properties, with a maximum energy product (BHmax) of 4.4 kJ/m³ and coercivities (Hcj = 35.7 kA/m, Hcb = 33.4 kA/m) exceeding those of the Alnico 5 benchmark (BHmax = 3.3 kJ/m³, Hcj = 30.3 kA/m, Hcb = 27.9 kA/m). Furthermore, the HEA exhibited superior thermal stability, maintaining its remanence with a more gradual decline up to 1030 K, in contrast to Alnico 5, which underwent a rapid decrease above 870 K. This work establishes a versatile approach for accelerating the design of sustainable magnetic materials with tailored properties, effectively bridging high-throughput thermodynamic modeling and advanced manufacturing.Peer reviewe
Development and Outdoor Testing Based on Monitoring Data and Finite Volume Models of Cool Asphalt Prototypes in HE MULTICLIMACT
Get PDFPublisher Copyright: © 2025 IEEE.The MULTICLIMACT project (MULTI-faceted CLIMate adaptation ACTions to improve resilience, preparedness, and responsiveness of the built environment against multiple hazards at multiple scales) aims to provide an integrated framework of tools to assist public actors and citizens at territorial, urban and individual building level. During the second year of this project, two outdoor cool asphalt pavement prototypes to mitigate heat islands at urban scale for the city of Barcelona, together with the corresponding reference sample, have been monitored and analyzed. Data has been collected from a monitoring system measuring the temperature of the asphalt of the three constructed samples and evaluated with a parametric Finite Volume Method model for thermal analysis. This model fits the monitoring system data and enables to infer the impact that the pavement would have on pedestrians. With the results of this study, which is presented halfway through the development and testing phase of the project, the first conclusions based on real data and analytical models on these designed asphalt solutions are obtained, and the elaborated finite volume models are validated as a reliable tool to fit the monitored reality. This will allow to evaluate feasible modifications in the final design of the cool asphalt pavement that will be deployed in a demonstration installation in the city of Barcelona in the next year of the MULTICLIMACT project.Peer reviewe
Enhancing water resistance of medium density fibreboards via periodate oxidation of thermomechanical fibres
Get PDFPublisher Copyright: © The Author(s) 2025.Medium density fibreboard (MDF) is an essential material in global manufacturing, valued for its versatility and cost-effectiveness. Enhancing its water resistance is critical for broadening its applications, especially in humid and outdoor environments. This study investigates the enhancement of MDF water resistance through the chemical modification of the constituent wood fibres (in this case, thermo-mechanical pulp or TMP) through periodate oxidation. The treatment with sodium metaperiodate results in the formation of dialdehyde fibres (DA-TMP) which are then spray-coated with a phenol-formaldehyde resin, following the industrial procedures, and converted into a MDF through proper hot pressing. Comprehensive evaluation of the physical, mechanical, and biological properties is conducted, along with the study of fire behaviour comparing boards made from both oxidized and non-oxidized fibres. The results reveal that periodate oxidation reduces water absorption by 54% and thickness swelling by 56%, indicating significant changes in the fibres’ chemistry and morphology. Despite a slight decrease in mechanical properties, the overall performance of DA-TMP based MDF confirms this as a promising method for achieving superior durability in moisture-prone environments, including outdoor constructions. Importantly, the biological resistance of the material remains unaffected by the oxidation of the fibres, ensuring continued protection against biological attack and long-term durability. Additionally, fire performance tests show that DA-TMP based MDF exhibit reduced peak heat release and smoke production, further enhancing their suitability for fire-sensitive applications. Consequently, this research contributes to expand the use and durability of wood-based materials across various industrial sectors, offering a sustainable and effective alternative to traditional moisture resistance treatments.Peer reviewe
Exploring Bandwidth Capabilities of Solar Cells for VLC Applications
No full textPublisher Copyright: © 2005-2012 IEEE.The growing number of connected wireless devices is causing interference in traditional radio frequency bands, which restricts communications capacity and efficiency. This issue motivates the pursuit of alternative technologies, such as optical wireless communication, which could potentially resolve electromagnetic congestion. This technology leverages the visible and infrared spectrum, along with other wavelengths, to transmit data. Recently, photovoltaic (PV) modules have emerged as an innovative solution for data reception and enhancing self-sufficiency. However, within a range of industrial settings, including factories, warehouses, and offices, data transmission may be affected by fluctuations in lighting conditions. This work focuses on exploring the impact of lighting conditions on the frequency response of visible light communication (VLC) systems that utilize silicon PV cells as photodetectors, a crucial aspect to optimize the efficiency of data transmission. This analysis opens new possibilities for the effective deployment of PV cells as optical receivers in indoor settings, thereby significantly enhancing the usage of VLC technology in industrial applications.Peer reviewe
Tailoring the properties of carbon molecular sieves membranes for the separation of propionic acid from aqueous solutions
Get PDFPublisher Copyright: © 2024 The AuthorsIn the fermentative production of propionic acid (PA), the major problem with batch fermentation systems is the strong inhibitory effect of PA on the production yield; one way to increase the yield is the in-situ removal of PA by using pervaporation. Acetic acid (AA) is the most important by-product in the fermentation; therefore, the membrane should be able to remove selectively PA from an aqueous solution containing AA. Considering that PA is more hydrophobic than AA and their kinetic diameter are 0.480 and 0.436 nm respectively, hydrophobic membranes with main pores in the range of around 0.5–0.6 nm with high permeation are required. Supported thin Carbon Molecular Sieve Membranes (CMSM) were prepared by the dip coating a porous alumina support into a solution containing resorcinol phenolic resin as carbon source. The hydrophobicity was obtained by carbonizing the polymer at temperatures higher than 750 °C and adding polyvinyl butyral (PVB) as pore forming agent and carbon contributor. PA with 88 % of purity was obtained by pervaporation of an aqueous solution containing 5 % of PA and 5 % of AA using a CMSM carbonized at 850 °C containing 1 % of PVB in the dipping solution.Peer reviewe
Semi-Supervised Approach for Automatic Counting of Whiteflies With Small Annotated Dataset
Get PDFPublisher Copyright: © 2013 IEEE.Insect counting is key action for pests’ control in agriculture. Automatic insect counting would allow a fast and accurate characterization of the infestation degree which would lead to a better choice of insecticide dose and, consequently, more effective treatments. Recently, an approach that automatically counts the insects in the wild has been proposed by Bereciartua-Pérez et al. That method is based on density map estimation with deep learning and has proven to offer very good results. Deep learning techniques, however, still present one big drawback: they rely on lots of annotated data. In the case of insect counting by density map estimation, the annotation process is a very tedious and time-consuming task and it entails an important bottleneck in the development of the model. In this paper, a new semi-supervised method is proposed for automatic counting of whiteflies with a small annotated dataset. Semi-supervised learning is based on leveraging not annotated data during training. Our semi-supervised method is based on the design and implementation of a pseudo-annotation algorithm that requires few annotated data. The pseudo-annotations obtained from this algorithm might be noisy but they help during the training of the whitefly counting model allowing to reduce the manual annotations needed and, therefore, reducing the effort and time needed to get a usable deep learning based solution for the task. Our new semi-supervised approach using only 48 manually annotated images achieves similar results as the fully supervised approach trained with 474 manually annotated images.Peer reviewe