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Construction and demolition waste in cement matrices as sinkholes of atmospheric pollution: Effect of the 2022 airborne dust in the Iberian Peninsula
Get PDFPublisher Copyright: © 2023 Elsevier B.V.The coincidence of a study on different ecocements to environmental exposition in Madrid (Spain) with the airborne dust from the Sahara desert in the same location, during the year 2022, facilitated the knowledge of the ecocement permeability to different sources of contamination. In general, mortars with a siliceous composition are more compact and less permeable to environmental particles compared to those with a calcareous composition. Binary mortars with glass have an intermediate response to pollutants and the most favorable for the incidence of contamination are ternary sulfoaluminate cements. The analysis of the ions penetration in the different cements studied has been followed by XRF, XRD-Rietveld and SEM/EDX analyses.This research, was conducted under a national project (grant number 359 RTI2018–097074- B-C21 and C-22 ) funded by the Spanish Ministry of Science, Innovation and Universities (MICIU).Peer reviewe
Application of 3D printing on the design and development of pharmaceutical oral dosage forms
Get PDFPublisher Copyright: © 20243D printing technologies confer an unparalleled degree of control over the material distribution on the structures they produce, which has led them to become an extremely attractive research topic in pharmaceutical dosage form development, especially for the design of personalized treatments. With fine tuning in material selection and careful design, these technologies allow to tailor not only the amount of drug administered but the biopharmaceutical behaviour of the dosage forms as well. While fused deposition modelling (FDM) is still the most studied 3D printing technology in this area, others are gaining more relevance, which has led to many new and exciting dosage forms developed during 2022 and 2023. Considering that these technologies, in time, will join the current manufacturing methods and with the ever-increasing knowledge on this topic, our review aims to explore the advantages and limitations of 3D printing technologies employed in the design and development of pharmaceutical oral dosage forms, giving special focus to the most important aspects governing the resulting drug release profiles.Peer reviewe
Data-driven and LCA-based Framework for environmental and circular assessment of Modular Curtain Walls
Get PDFPublisher Copyright: © 2024 TU Delft. All rights reserved.To assist the sustainable development of the building sector, designers require tools illustrating the most viable design options. This paper, starting by presenting the opportunities and limitations of the Life Cycle Assessment (LCA) methodology and Digital Product Passport (DPP) instrument when applied to Custom Modules for Curtain Walls, proposes a Semantic Data-driven Framework to facilitate the design of low-carbon and circular façade modules. Based on literature and the practical outcome of the H2020 project Basajaun, this framework integrates computer-aided technologies that manufacturing companies commonly employ to automate an efficient sustainability assessment process using primary data. This solution innovates industrial process management and architectural design and supports the creation of greener products. It also facilitates the output of documents supporting end-of-life scenarios. The development methodology involves investigating required quantitative project data, environmental factors, and circularity information, as well as the definition of flowcharts for the Life Cycle Inventory, extending a best practice for the façade module's DPP. Furthermore, the methodology implicates data collection and IT implementation and organisation. This is through the definition of an ontology conceived for interconnection between digital systems. The findings shall contribute to implementing the LCA and DPP practices for custom prefabricated façade modules and suggest areas for further development. Challenges include obtaining and sharing data on environmental impacts and circularity, but involving stakeholders and addressing technical limitations can improve sustainability.Peer reviewe
STRUCTURAL REHABILITATION WITH TIMBER-TIMBER COMPOSITE FLOORS IN ITSASO TOWNHALL
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MIXED RECYCLED AGGREGATES CLASSIFICATION USING IMAGING AND DEEP-LEARNING TECHNIQUES FOR EFFECTIVE WASTE MANAGEMENT IN REHABILITATION WORKS
No full textPublisher Copyright: © 2024, University of Cantabria - Building Technology R&D Group. All rights reserved.The rehabilitation and renovation of existing buildings generate significant amounts of construction and demolition waste (CDW) [1]. Proper classification of this waste is crucial for effective waste management and resource recovery. However, identifying and classifying the waste can be a tedious, costly, and error-prone process, which can lead to inadequate treatment and have a significant impacton the environment. This study focuses on the development and laboratory testing of advanced classification methods based on image processing and semantic segmentation to classify mixed recycled aggregate fractions. A comprehensive comparison is made between two different approaches: a semantic segmentation without ground truth, i.e. training the neural network without a reference target, and ase mantic segmentation trained after exhaustive labeling of the classes. A dataset of images of different types of CDW, including pure samples of concrete, ceramics, and plaster, as well as prepared mixtures, was collected, labeled, and segmented. The study applies deeplearning techniques and evaluates the performance of the two methods by quantifying the amount ofeach component in the image. The first approach involves training a supervised semantic segmentation network to learn the distinctive features of each pure class of material without mixing and assigning semantic labels to pixels. The second approach involves manual labeling of the classes in mixed samplesas ground truth for the model. The results reveal that both approaches have distinct advantages and disadvantages. The ground truth- based approach provides an accurate and reliable reference but requires considerable effort in manual labeling. On the other hand, the classifier training approach is more efficient in terms of time and resources but may be subject to classification errors. We further show that fine-tunning the ground truth-free model on few labeled samples outperforms both alternatives and represents a data-efficient trade-off. In conclusion, this study demonstrates the potential of deep-learning techniques with image analysis for cost-effective CDW classification. The results obtained in this research can serve as a basis for developing more accurate and reliable methods for CDW identification, contributing to sustainable CDW management for rehabilitation and renovation works.Peer reviewe
Exploiting Axisymmetry to Optimize CFD Simulations—Heave Motion and Wave Radiation of a Spherical Buoy
Get PDFPublisher Copyright: © 2024 by the authors.Simulating the free decay motion and wave radiation from a heaving semi-submerged sphere poses significant computational challenges due to its three-dimensional complexity. By leveraging axisymmetry, we reduce the problem to a two-dimensional simulation, significantly decreasing computational demands while maintaining accuracy. In this paper, we exploit axisymmetry to perform a large ensemble of Computational Fluid Dynamics (CFDs) simulations, aiming to evaluate and maximize both accuracy and efficiency, using the Reynolds Averaged Navier–Stokes (RANS) solver interFOAM, in the opensource finite volume CFD software OpenFOAM. Validated against highly accurate experimental data, extensive parametric studies are conducted, previously limited by computational constraints, which facilitate the refinement of simulation setups. More than 50 iterations of the same heaving sphere simulation are performed, informing efficient trade-offs between computational cost and accuracy across various simulation parameters and mesh configurations. Ultimately, by employing axisymmetry, this research contributes to the development of more accurate and efficient numerical modeling in ocean engineering.Peer reviewe
Design Strategies for an Effective Implementation of Solar Harvesting Façades into Pre-Existing HVAC Systems in Buildings Renovation
No full textPublisher Copyright: © 2024 University of Split, FESB.Building renovation plays a key role on the path to low-carbon economy, yet the increasing complexity and cost of decarbonization strategies to reach nearly zero-energy buildings (NZEB) is a major challenge that hinders the potential of retrofitting the existing building stock. Multifunctional façade solutions appear as a feasible solution on this regard. This paper presents a novel methodology conceived to serve as a standardized approach for an effective implementation of solar harvesting-multifunctional façades into pre-existing HVAC systems in buildings renovation. The design strategies presented consider users' needs, different renovation scenarios and operation possibilities while ensuring an optimal use of renewable energy sources. The methodology is supported on building simulation and applied to a real case study, including pre-sizing and evaluation of different configurations to optimize the solar production and the thermal storage. The work shows a number of constraints and limitations that must be effectively addressed, ensuring the user's needs as well as the efficient operation of all systems, both existing and new. Main constrains encountered on the integration process are building geometry, user priorities, and the pre-existence of an HVAC system, being a central thermal storage system selected as the preferred solution for the integration with the pre-existing installation while optimizing solar fraction through an adequate building management strategy. The methodology is successfully applied in a demo-case on Tartu, demonstrating the capacity for integrating the solutions on existing HVAC configuration, with a potential reduction of up to 21 tons of annual GHG emissions.Peer reviewe
Control of electric drives withhighswitching frequency operation capabilitiesenvisioning future prospects
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Second-Order Filter-Based Inertia Emulation (SOFIE) for Low Inertia Power Systems
No full textPublisher Copyright: © 1986-2012 IEEE.The massive integration of power electronic converters into the power grid has led to a decrease in the mechanical inertia of power systems, causing an increase in the rate of change of frequency (RoCoF) that may lead to stability problems. The scientific community has focused on developing grid-forming control techniques, although their implementation implies a significant change in the firmware of the converter. Grid-supporting approaches, on the other hand, are an interesting alternative to add frequency support to the grid while preserving the original control structure of the converter. This article proposes three new grid-supporting control techniques based on the dynamic behaviour of a synchronous machine (SM) and its equivalence with a second-order low-pass filter. They endow the converter with the capability of providing synthetic inertia, damping, droop-based p/f primary response and virtual reactance. The dynamics of the proposed implementations are compared with a reduced-order synchronous machine by means of time-domain simulations and in-depth state-space-based small signal analyses. Besides, their operation is validated in a nine-bus low-inertia power system. Hardware-in-the-loop (HIL) laboratory results are used to validate experimentally the proposed techniques.Peer reviewe
A1–A5 Embodied Carbon Assessment to Evaluate Bio-Based Components in Façade System Modules
Get PDFPublisher Copyright: © 2024 by the authors.As the construction industry moves toward sustainable building practices, incorporating wood-based materials into building envelope systems has become a priority. This paper investigates the environmental impact of three custom bio-composite Façade System Modules (FSMs) through an Embodied Carbon Assessment (ECA), focused on the Global Warming Potential indicator of life cycle stages from cradle to practical completion (A1–A5). The evaluated FSMs were developed within the Basajaun H2020 project (G.A. 862942), by substituting and combining conventional materials with other bio-composite products to form hybrids from bio-based polymers and wood. A benchmark ECA was conducted, simulating alternative FSMs devised with common practice solutions for the curtain wall façade to facilitate a comprehensive comparison. The life cycle inventory encompassed detailed technical information, fostering the utilization of primary data for accuracy. The study particularly highlights considerations over three technological systems of the modules that incorporate increased use of wood-based components and a novel bio-composite material: the frame profiles, the insulation equipment, and the seal system. Despite the challenges due to the Basajaun FSMs’ weight, the findings reveal that replacing the currently used materials with wood-based materials and bio-composites reduced the embodied emissions, particularly substituting aluminum frame profiles. The insights presented here offer indicators toward circular, environmentally conscious, bio-composed building envelopes, emphasizing the need for continued analysis and refinements as a consequence of increasing the accuracy of the available primary data from the supply chain and concerning end-of-life scenarios.Peer reviewe