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Nano-Photonic Crystal D-Shaped Fiber Devices for Label-Free Biosensing at the Attomolar Limit of Detection
No full textPublisher Copyright: © 2024 The Author(s). Advanced Science published by Wiley-VCH GmbH.Maintaining both high sensitivity and large figure of merit (FoM) is crucial in regard to the performance of optical devices, particularly when they are intended for use as biosensors with extremely low limit of detection (LoD). Here, a stack of nano-assembled layers in the form of 1D photonic crystal, deposited on D-shaped single-mode fibers, is created to meet these criteria, resulting in the generation of Bloch surface wave resonances. The increase in the contrast between high and low refractive index (RI) nano-layers, along with the reduction of losses, enables not only to achieve high sensitivity, but also a narrowed resonance bandwidth, leading to a significant enhancement in the FoM. Preliminary testing for bulk RI sensitivity is carried out, and the effect of an additional nano-layer that mimics a biological layer where binding interactions occur is also considered. Finally, the biosensing capability is assessed by detecting immunoglobulin G in serum at very low concentrations, and a record LoD of 70 aM is achieved. An optical fiber biosensor that is capable of attaining extraordinarily low LoD in the attomolar range is not only a remarkable technical outcome, but can also be envisaged as a powerful tool for early diagnosis of diseases.Peer reviewe
Revealing the Capability of an LMR Microfluidic Biosensor for Celiac Disease Diagnosis via Label-Free Detection of Antigliadin Antibodies
No full textPublisher Copyright: © 2017 IEEE.Celiac disease (CD) is a chronic autoimmune disorder triggered by gluten consumption, which affects between 0.5% and 1% of the global population. Current diagnostic methods still require invasive pro-cedures, such as intestinal biopsy. Lossy mode resonance (LMR)-based sensors hold great potential for the development of reliable and user-friendly devices for diagnosing this condition. In this letter, an LMR planar microfluidic system is used to perform the label-free detection of different concentrations of antigliadin antibodies, one of the biomarkers of celiac disease, achieving a limit of detection of 1 μg/mL. The speci- ficity of the sensor to the target analyte is also proved, and the validation of the biofunctionalization process is comple- mented with an atomic force microscope analysis.Peer reviewe
Operation Of Solid Oxide Fuel Cells (SOFC) with Biogas Generated from Agri-Food Waste: Optimisation of Biogas Production and Analysis of Cell Performance
No full textPublisher Copyright: Copyright © 2024, AIDIC Servizi S.r.l.Due to the internal reforming that takes place in solid oxide fuel cells, they can operate with the (bio)methane contained in the biogas produced by anaerobic digestion (AD) from organic waste. In this sense, the potential of agri-food waste (onion skins) for biogas production and its use in SOFCs has been analyzed. For this purpose, physical, chemical, thermal, and combined pretreatments were tested on onion skins to increase the anaerobic biodegradability. The evaluated pretreatments increased the soluble chemical oxygen demand (SCOD). However, it was observed that the use of Ca(OH)2 was preferred to NaOH, because it allowed the precipitation of sulphates, blocking the biological production of H2S, which acts as a toxic compound for methanogenic archaea and as a catalytic poison of SOFC systems. This combination of pretreatments increased methane production by 36 and 19 % compared to untreated substrate. Once the most suitable pretreatment was identified, the biogas produced was used to feed a SOFC optimized by advanced ceramic processing to operate with this biofuel. The electrochemical performance of SOFC was examined through the characterization of I-VP and EIS curves for H2 and the obtained biogas as fuels, operating at different temperatures: 800, 850, and 900 °C.Peer reviewe
A novel python-based floating offshore wind turbine simulation framework
No full textPublisher Copyright: © 2024 The AuthorsThe expansion of floating offshore wind brings the industry closer to achieving commercial viability. However, the challenging environment characterised by strong winds, waves, and currents, along with the growing size of wind turbines and the dynamic behaviour of floaters, introduces concerns about power production efficiency and system durability due to increased fatigue loads, which subsequently impacts overall costs. In an attempt to mitigate the financial implications coming from alterations made to control strategies and structural elements during the initial design phase, this paper propounds an all-encompassing simulation framework for offshore wind turbines. The current study thoroughly explores the various capabilities of the tool, with a focus on its simulation models. Importantly, the paper highlights the complex interactions between tool models and different controllers. Carefully designed, this tool offers users a variety of functions to enhance system design, fine-tune control strategies, and thoroughly assess performance metrics. The paper elaborates on these aspects, providing an explanation of the tool's capabilities and enhancing the dynamic comparison between the models.The work was funded by the Basque Government through the BIKAINTEK PhD support program (grant no. 48-AF-W2-2019-00010 ), and through the Elkartek program (grant no. KK-2022/00090 , KONFLOT project). The authors acknowledge NAUTILUS Floating Solutions for their support to the PhD thesis of Javier Lopez-Queija. The research has been carried out within the framework of the Joint Research Laboratory on Offshore Renewable Energy (JRL-ORE). The authors also acknowledge EUSKAMPUS FUNDAZIOA for their support through the Misiones 1.0 program. The work was funded by the Basque Government through the BIKAINTEK PhD support program (grant no. 48-AF-W2-2019-00010 ), and through the Elkartek program (grant no. KK-2022/00090 , KONFLOT project). The authors acknowledge NAUTILUS Floating Solutions for their support to the PhD thesis of Javier Lopez-Queija. The research has been carried out within the framework of the Joint Research Laboratory on Offshore Renewable Energy (JRL-ORE) . The authors also acknowledge EUSKAMPUS FUNDAZIOA for their support through the Misiones 1.0 program. In the proposed optimization framework, a range of complexity level models can be employed. For the optimised system validation a complex dynamic model, OpenFAST [11], supported by NREL, is used. While the system dimensions and controllers optimization process utilises a low complexity dynamic model based on the work in Ref. [28]. Additionally, the tool's modular framework enables users to easily incorporate any other FOWT model of their choice. In this study, the dynamic performance of the low complexity model is compared with the more complex OpenFAST model to validate the suitability of the low complexity model for optimization processes.As discussed in Section 2, a more comprehensive dynamic time domain model is required to validate the optimised designs obtained. In this initial version of the tool, OpenFAST [11], supported by NREL, is utilised for this purpose. OpenFAST is a multi-physics, multi-fidelity tool for simulating the coupled dynamic response of wind turbines, both onshore and floating. The code is integrated with modules that encompass aerodynamics, hydrodynamics for offshore foundations, control, and electrical system dynamics, as well as structural dynamics, enabling nonlinear time domain simulations.The work was funded by the Basque Government through the BIKAINTEK PhD support program (grant no. 48-AF-W2-2019-00010), and through the Elkartek program (grant no. KK-2022/00090, KONFLOT project). The authors acknowledge NAUTILUS Floating Solutions for their support to the PhD thesis of Javier Lopez-Queija. The research has been carried out within the framework of the Joint Research Laboratory on Offshore Renewable Energy (JRL-ORE). The authors also acknowledge EUSKAMPUS FUNDAZIOA for their support through the Misiones 1.0 program.Peer reviewe
Corrosion Rate and Mechanism of Degradation of Chitosan/TiO2 Coatings Deposited on MgZnCa Alloy in Hank’s Solution
No full textPublisher Copyright: © 2024 by the authors.Overly fast corrosion degradation of biodegradable magnesium alloys has been a major problem over the last several years. The development of protective coatings by using biocompatible, biodegradable, and non-toxic material such as chitosan ensures a reduction in the rate of corrosion of Mg alloys in simulated body fluids. In this study, chitosan/TiO2 nanocomposite coating was used for the first time to hinder the corrosion rate of Mg19Zn1Ca alloy in Hank’s solution. The main goal of this research is to investigate and explain the corrosion degradation mechanism of Mg19Zn1Ca alloy coated by nanocomposite chitosan-based coating. The chemical composition, structural analyses, and corrosion tests were used to evaluate the protective properties of the chitosan/TiO2 coating deposited on the Mg19Zn1Ca substrate. The chitosan/TiO2 coating slows down the corrosion rate of the magnesium alloy by more than threefold (3.6 times). The interaction of TiO2 (NPs) with the hydroxy and amine groups present in the chitosan molecule cause their uniform distribution in the chitosan matrix. The chitosan/TiO2 coating limits the contact of the substrate with Hank’s solution.Peer reviewe
Electrotactile BCI for Top-Down Somatosensory Training: Clinical Feasibility Trial of Online BCI Control in Subacute Stroke Patients
No full textPublisher Copyright: © 2024 by the authors.This study investigates the feasibility of a novel brain–computer interface (BCI) device designed for sensory training following stroke. The BCI system administers electrotactile stimuli to the user’s forearm, mirroring classical sensory training interventions. Concurrently, selective attention tasks are employed to modulate electrophysiological brain responses (somatosensory event-related potentials—sERPs), reflecting cortical excitability in related sensorimotor areas. The BCI identifies attention-induced changes in the brain’s reactions to stimulation in an online manner. The study protocol assesses the feasibility of online binary classification of selective attention focus in ten subacute stroke patients. Each experimental session includes a BCI training phase for data collection and classifier training, followed by a BCI test phase to evaluate online classification of selective tactile attention based on sERP. During online classification tests, patients complete 20 repetitions of selective attention tasks with feedback on attention focus recognition. Using a single electroencephalographic channel, attention classification accuracy ranges from 70% to 100% across all patients. The significance of this novel BCI paradigm lies in its ability to quantitatively measure selective tactile attention resources throughout the therapy session, introducing a top-down approach to classical sensory training interventions based on repeated neuromuscular electrical stimulation.Peer reviewe
Influence of Yttria content in YSZ: An evaluation of water-based SPS coatings and spark plasma sintered pellets
No full textPublisher Copyright: © 2024 The AuthorsThe inherent phase instability of the state-of-the-art 7–8 mol% partially stabilised Yttria-Stabilised Zirconia (YO1.5, 8 YSZ, tetragonal) under a molten CMAS attack lacks the technological readiness needed to increase the gas inlet temperatures for more thermally efficient gas turbine engines. In this study, the concentration of Yttria in YSZ was systemically increased to impart CMAS resistance and their applicability via emerging Suspension Plasma Sprayed (SPS) coatings and Spark Plasma Sintered (SpPS) pellets under simulated conditions was evaluated. The fully stabilised higher Yttria YSZ compositions (21.4 mol% and 50.2 mol%, cubic) severely restricted the CMAS infiltration and interaction areas, with the later composition forming an apatite layer and the trans-granular cracking and chipping of YSZ into layers reduced with an increase in Yttria content. However, their application into water-based SPS coatings resulted in a complete coating failure following the high-temperature CMAS tests. During Furnace Cycling Test (FCT) tests, the 8 YSZ coating survived 34 thermal cycles compared to just one on the 50.2 mol% YSZ coatings. The premature delamination of the higher Yttria coating seems to have been caused by the spallation associated with horizontal cracks within the coating. The YSZ composition could be modified into CMAS-resistant chemistry; however, their applicability as a functioning TBC with inherent microstructural features, such as the Dense Vertically Cracked (DVC) coating strategy examined in this study, requires new coating design strategies that impart sustainable thermal cycling performance.Peer reviewe
Scale Mutualized Perception for Vessel Border Detection in Intravascular Ultrasound Images
No full textPublisher Copyright: © 2004-2012 IEEE.Vessel border detection in IVUS images is essential for coronary disease diagnosis. It helps to obtain the clinical indices on the inner vessel morphology to indicate the stenosis. However, the existing methods suffer the challenge of scale-dependent interference. Early methods usually rely on the hand-crafted features, thus not robust to this interference. The existing deep learning methods are also ineffective to solve this challenge, because these methods aggregate multi-scale features in the top-down way. This aggregation may bring in interference from the non-adjacent scale. Besides, they only combine the features in all scales, and thus may weaken their complementary information. We propose the scale mutualized perception to solve this challenge by considering the adjacent scales mutually to preserve their complementary information. First, the adjacent small scales contain certain semantics to locate different vessel tissues. Then, they can also perceive the global context to assist the representation of the local context in the adjacent large scale, and vice versa. It helps to distinguish the objects with similar local features. Second, the adjacent large scales provide detailed information to refine the vessel boundaries. The experiments show the effectiveness of our method in 153 IVUS sequences, and its superiority to ten state-of-the-art methods.Peer reviewe
Influence of Al addition on microstructure and electrochemical behaviour of CrMnFeCoNi high-entropy alloy
Get PDFPublisher Copyright: © 2024 The AuthorsTo develop new corrosion-resistant materials for structural applications, CrMnFeCoNiAlx high-entropy alloys (HEAs) are produced via semi-industrial induction casting. The study aimed to investigate the influence of Al content (x = 0–0.3) on both microstructure evolution and corrosion properties of the alloys. X-ray diffraction and scanning electron microscopy (SEM) analysis revealed that all the alloys exhibited a single-phase face-centered cubic structure, with dendritic (Fe, Co, Cr-rich) and interdendritic (Mn, Ni, Al-rich) regions distinguished by elemental segregations. Furthermore, the incorporation of Al atoms into the solid solution led to an increase in the lattice parameter, indicating alloy strengthening. The corrosion resistance of the CrMnFeCoNiAlx alloy improved with higher Al addition. Electrochemical polarisation tests demonstrated a slight increase in the corrosion potential (Ecorr) and a significant decrease in the corrosion current density (icorr) upon Al addition. Additionally, slower kinetics for pit nucleation (higher E'corr) were observed, particularly notable for x = 0.3. Analysis of the corroded surfaces revealed a mixed degradation mechanism, involving pitting corrosion and selective dissolution of the interdendritic zone, which decreased as the Al content of the HEA increased. These findings underscore the effectiveness of Al addition in not only enhancing the mechanical properties of the Cantor alloy through solid solution strengthening, but also improving its corrosion resistance.Peer reviewe
Quantum key distribution: a survey on current vulnerability trends and potential implementation risks
Get PDFPublisher Copyright: © 2024 Optica Publishing Group.Quantum key distribution (QKD) is a cryptographic technique that enables secure private key exchange between geographically distant parties over an insecure channel, protecting confidentiality against potential eavesdroppers. QKD has evolved significantly since its inception with the BB84 protocol proposed by Bennett and Brassard in 1984. Its theoretical foundation relies on quantum physics, particularly the uncertainty principle, the no-cloning theorem, and particle entanglement, which ensures its information-theoretic security when combined with the one-time-pad cryptographic algorithm. However, certain security loopholes persist in terms of practical implementation in commercial devices. Some vulnerabilities are associated with side-channel vectors linked to commonly used optical subcomponents, while others are more related to how existing protocols handle encoding and communication pipelines. In this work, we aim to comprehensively study the current state of security loopholes affecting QKD technology in commercial devices. We also provide a concise overview of the existing types of QKD implementations. Additionally, we offer insights into current trends and vulnerability countermeasures, paving the way for future research and novel mechanisms to enhance the implementation security of commercial QKD devices.Peer reviewe