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Wood Reconfiguration Enables Broadband Blackbody in Large-Area, Modular, Optically Welded Carbon Constructs
No full textA broadband blackbody requires both perfect anti-reflective characteristics and effective light entrapment spanning wavelengths from the mid-infrared (MIR) to the ultraviolet (UV) range. This ideal combination has not been achieved in several artificial superblack systems or even in naturally occurring superblack structures. A broadband blackbody is created by carbonizing delignified wood infused with lignin particles (LPs), forming a reconfigured wood (cRW) system. The LPs enhance the dimensional fidelity of cRW and promote the development of sparse, highly aligned fibrillar microstructures, achieving super-absorbance levels spanning from the MIR to the UV wavelengths, reaching over 99.8% absorption. This performance is further amplified in large-area light traps constructed from tiled cRW, which are optically welded, modular and customizable in size and shape. The tiled cRW configuration effectively eliminates thermal ghost reflections and outperforms individual cRW units. This system is demonstrated as a perfect broadband blackbody, which can act as promising reference infrared radiator in IR thermography that benefit from precise sensor calibration. Altogether, this optically welded superabsorber trap introduces a wood-based solution for broadband blackbody materials, opening new opportunities across diverse applications.</p
Extraction of brominated flame retardants from acrylonitrile butadiene styrene (ABS) using supercritical carbon dioxide
Full text linkElectrical and electronic equipment, as well as construction materials, commonly contain brominated flame retardants (BFRs), which are harmful to human health and the environment. These additives can cause major issues during disposal or recycling phases and, hence, methods to remove them are highly demanded. This study focuses on removing three BFRs, namely Tetrabromobisphenol A (TBBPA), Decabromodiphenyl Ether (decaBDE), and Hexabromocyclododecane (HBCD) from acrylonitrile butadiene styrene (ABS) plastic using supercritical carbon dioxide (scCO2) extraction. Virgin ABS compounds with known BFR concentrations were prepared by melt extrusion and injection moulding, and the scCO2 extraction parameters, including extractor configuration, extraction time, pressure, temperature, type of co-solvents and physical dimensions of the sample, were optimized. To further remove the BFRs, samples were then cleaned in a pressure extractor with isopropanol (hybrid approach), achieving high BFR removal efficiency. The elemental bromine and BFR concentrations in the samples, both before and after the scCO2 extraction, were examined by X-ray fluorescence (XRF) analysis and mass spectrometry, respectively. In a semi-continuous configuration for the scCO2 extractor at 100 °C and ethanol co-solvent we effectively removed all three BFRs achieving a maximum bromine extraction of 84.3% from ABS-TBBPA samples during 240 min. In the hybrid approach, the extraction increased to 89.4% by treating the samples in the pressure extractor
Preparation and Papermaking Properties of Dry-Cut Powder from Chemically Crosslinked BEKP
Full text linkChemical crosslinking of cellulosic fibers increases their brittleness, making them more susceptible to dry powdering. In this study, bleached eucalyptus kraft pulp (BEKP) sheets were crosslinked with glyoxal (GO) and citric acid (CA) and subsequently dry cut into powders using a Wiley cutting mill. Key variables in the powder preparation were dosages of GO and CA, as well as their respective catalysts, aluminum sulphate (alum) and sodium hypophosphite (SHP). The average fiber length of the GO and CA crosslinked pulps was reduced, at most down to 0.12 and 0.17 mm by the dry cutting, using a 0.5 mm perforated screen in the final dry-cutting stage. The powders exhibited reduced water retention, lower sedimentation volume in water, and, when dry, showed increased tapped and bulk densities. When mixed with refined BEKP, the powders enhanced dewatering during handsheet formation and improved the resulting sheets’ bulk, light scattering, and opacity, while reducing tensile strength. These findings suggest that chemically crosslinked pulp powders have potential as a bulking and dewatering aid in papermaking. Furthermore, due to their low water absorbency and presumable low abrasiveness, the powder may have potential applications beyond papermaking, such as filler of plastics, glues, and coating materials
A probabilistic-driven approach for early design quality risk and crux identification using non-Markovian stochastic Petri nets
Full text linkQuality risk analysis of high-process-oriented systems, which refers to their ability to achieve required tasks on time, receives little attention during the early conceptual design stage, primarily due to the high level of abstraction when the system form is not yet fully defined. Although several mathematical methods exist to address this issue, they are fragmented across domains and lack a unified integration into early design practice. To address this problem, this paper introduces a novel approach that models design problems as discrete events with output conflict representation, using the non-Markovian stochastic Petri net. The framework is further integrated with mathematical techniques, including semi-Markov performance evaluation, sensitivity analysis, and uncertainty analysis, to quantify quality risks and identify the design crux (the most critical design parameters). By incorporating Monte Carlo simulations, it facilitates designers and engineers with early insights and allows them to compare alternative design specifications. Its applicability is demonstrated through a case study on the conceptual development of a remote maintenance system for the In-Bioshield area of the EU-DEMO fusion power plant. Initial results showed potential in identifying quality risks, addressing key factors contributing to the design problem, and finding optimal design specifications in the early stages
Wood Reconfiguration Enables Broadband Blackbody in Large-Area, Modular, Optically Welded Carbon Constructs
No full textA broadband blackbody requires both perfect anti-reflective characteristics and effective light entrapment spanning wavelengths from the mid-infrared (MIR) to the ultraviolet (UV) range. This ideal combination has not been achieved in several artificial superblack systems or even in naturally occurring superblack structures. A broadband blackbody is created by carbonizing delignified wood infused with lignin particles (LPs), forming a reconfigured wood (cRW) system. The LPs enhance the dimensional fidelity of cRW and promote the development of sparse, highly aligned fibrillar microstructures, achieving super-absorbance levels spanning from the MIR to the UV wavelengths, reaching over 99.8% absorption. This performance is further amplified in large-area light traps constructed from tiled cRW, which are optically welded, modular and customizable in size and shape. The tiled cRW configuration effectively eliminates thermal ghost reflections and outperforms individual cRW units. This system is demonstrated as a perfect broadband blackbody, which can act as promising reference infrared radiator in IR thermography that benefit from precise sensor calibration. Altogether, this optically welded superabsorber trap introduces a wood-based solution for broadband blackbody materials, opening new opportunities across diverse applications.</p
Exploring the hydration potential and kinetics of Na-Ye'elimite and Ti-Ferrite solid solutions
No full textThe addition of Bauxite residue in the raw mix introduces Na+ and Ti4+ into the crystalline phases of calcium-sulfoaluminate (CSA) clinkers. To mimic such a system, Na-Fe-ye'elimite (C₃.₉N₀.₁A₂.₈F₀.₂Ŝ) and Ti-ferrite (C₂F₀.₇₆A₀.₂₄T₀.₁) were synthesized at 1285 °C, 2 h, and 1320 °C, 3 h, respectively. Quantitative X-ray diffraction (QXRD) revealed solid solutions with minor Ca-aluminates phases, whereas electron backscattered diffraction-energy dispersive spectroscopy (EBSD-EDS) could distinguish Na-rich orthorhombic and Fe-rich cubic ye'elimite polymorphs. Isothermal calorimetry showed the Na-Fe-ye'elimite phase drives early heat evolution, whereas higher ferrite and gypsum (M > 0) prolong induction and attenuate the main hydration peak. In ferrite-free mixes, the cubic-ye'elimite polymorph dissolves fastest, but when ferrite exceeds 33 wt%, its Fe3+ release accelerates orthorhombic-ye'elimite dissolution, as confirmed by pore-solution analysis. After 28d, Na-Fe-ye'elimite is fully consumed at M (sulfate to ye'elimite molar ratio) ≥ 2 for ye'elimite-ferrite mixes, while ferrite remains partly inert, possibly from Ca2+/SO₄2− adsorb onto its Fesingle bondAl surface. Limiting ferrite to ≤33 wt% is recommended to achieve more densification of the microstructure for better performance
Deep learning for green energy: predicting consumption and production trends across the Americas
No full textGreen energy projections can help meet rising energy needs, address climate change, and other challenges by forecasting future trends. This study uses data from 1965 to 2023 to predict American green energy production and consumption. The gated recurrent unit model was chosen because it shows the time-dependent structure in the data time series. This study utilized energy consumption and renewable generation sources from Kaggle, spanning from 1965 to 2022, and data from the Energy Institute website, covering the period from 2022 to 2023. The model has a mean absolute error of 0.0417 and 0.0341 for consumption and production, respectively, and a mean squared error of 0.0110 and 0.0083 for production. The GRU model achieves the highest accuracy, identifying green energy data trends with an RMSE of 0.1049 for consumption and 0.0912 for output. This study shows how this model predicts energy needs. It emphasizes the integration of renewable energy and innovation in resource distribution. The research says the Quest for More Sustainable energy systems must overcome predicted technical challenges. All stakeholders gain from improved energy management policies with this knowledge. The GRU model’s performance enables the incorporation of economic and meteorological data to enhance prediction accuracy and support global efforts to clean up the energy system
A nodalization study on modeling the containment and reactor pool of an integral PWR
Full text linkThis study investigates the impact of nodalization of the containment and reactor pool of a small integral Pressurized Water Reactor (iPWR) using the MELCOR 2.2 code. The research focuses on Design 1 of the EU-funded SASPAM-SA project, featuring a containment partially submerged in the reactor pool. Two accident scenarios were analyzed: a Design Basis Accident (DBA) and a severe accident. The simulations were conducted with four different nodalizations: a detailed base model, a single-volume containment model, a single-volume pool model, and a single-volume model for both the containment and the pool. The results indicate that while detailed nodalization can simulate temperature stratification, its effect on the overall accident simulation results, pressures and fission product releases is limited. The findings suggest that differences between single-volume and more detailed nodalizations are relatively small, with the detailed nodalization providing slightly lower containment pressures during the DBA scenario due to more efficient heat transfer
Some Problems in the Ethical Impact Assessment of Emerging Technologies and Socio-Technical Visions:Case CityVerse
No full textThis paper examines methodological challenges in the participatory ethical assessment of emerging technologies in urban contexts, using the CityVerse vision in Tampere, Finland as a case study. While metaverse technologies promise to transform smart cities by blending physical and virtual spaces, their ethical implications remain unclear. Through focus groups with city officials, we explored how participatory methods can effectively evaluate ethical dimensions of emerging technologies when they remain largely conceptual. Our findings reveal that while stakeholders can generate substantive ethical discourse, they struggle with the abstract nature of metaverse experiences, producing more questions than definitive answers. We argue that sociotechnical visions serve better as platforms for ethical discourse than as concrete implementation plans, functioning primarily to surface tacit values and assumptions. The study contributes to ethical technology assessment methodologies by suggesting that for emerging technologies, developing structured ontologies of questions may prove more valuable than premature answers. We conclude that CityVerse design should be approached as an ongoing discourse—not merely about technologies, but fundamentally about designing for improved quality of human life—where participatory ethical vision assessment functions as a form of collaborative conceptual engineering.</p
An Intelligent Optimization-Based Residual Negative Magnitude Shaping Scheme for Vibration Control
No full textWith the rapid advancement of modern manufacturing, suppressing residual vibrations in flexible and underactuated systems has become a critical challenge. Input shaping (IS) has garnered attention for its effectiveness in mitigating vibrations and enhancing motion performance. However, existing input shapers typically encounter unavoidable time delays (TDs), modeling inaccuracies, ineffective multimodal suppression and poor adaptability, limiting their control performance. Targeting at overcome these critical issues, this article proposes an intelligent optimization-based residual negative magnitude (NM) shaping vibration (IRV) control scheme with two novel ideas: 1) employing a data-driven differential evolution (DE) algorithm to estimate system errors; and 2) designing a robust particle swarm optimization (PSO)-based residual negative magnitude (PR) shaper to reduce TDs and compensate for modeling inaccuracies in multimodal vibration systems, thereby enhancing control adaptability to diverse system configurations. To validate its performance, eight real-world datasets have been established and made publicly available. Empirical studies demonstrate that the proposed PR shaper outperforms state-of-the-art shapers, and the IRV scheme achieves significant vibration suppression, reducing maximum residual vibrations by at least 9.26% compared to conventional methods. These advancements substantially improve vibration control in precision systems.</p