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Resilient microgrid formation in unbalanced AC/DC hybrid distribution system considering DC interconnections
No full textMicrogrid formation (MF) is an essential method for enhancing distribution system resilience. Existing MF research focuses on AC distribution systems, where the formed microgrids must satisfy the radial operation constraints. However, with the increasing penetration of DC sources and loads, the distribution network is transitioning from an AC configuration to a hybrid AC/DC configuration that can operate in a ring structure. Thus, traditional MF methods achieve limited critical load restoration of these systems. To achieve the most efficient restoration of AC/DC hybrid systems, this paper developed a novel MF method leveraging DC line interconnections. First, an energization route-based analytical model is developed for the decision-making of an microgrid topology containing DC lines. The energization status of AC and DC lines is differentially modelled to enable flexible interconnection and energy transfer between microgrids. Then, a coordinated scheduling model for resilient hybrid distribution systems is established, with the goal of increasing critical load supply. To mitigate the unbalanced current from three-phase AC loads, the use of flexible voltage source converter power control is emphasized. Furthermore, the original nonlinear model is linearized for tractability. The simulation results validate the merits of proposed MF method for improving the resilience of AC/DC hybrid distribution systems
Resilient microgrid formation in unbalanced AC/DC hybrid distribution system considering DC interconnections
No full textMicrogrid formation (MF) is an essential method for enhancing distribution system resilience. Existing MF research focuses on AC distribution systems, where the formed microgrids must satisfy the radial operation constraints. However, with the increasing penetration of DC sources and loads, the distribution network is transitioning from an AC configuration to a hybrid AC/DC configuration that can operate in a ring structure. Thus, traditional MF methods achieve limited critical load restoration of these systems. To achieve the most efficient restoration of AC/DC hybrid systems, this paper developed a novel MF method leveraging DC line interconnections. First, an energization route-based analytical model is developed for the decision-making of an microgrid topology containing DC lines. The energization status of AC and DC lines is differentially modelled to enable flexible interconnection and energy transfer between microgrids. Then, a coordinated scheduling model for resilient hybrid distribution systems is established, with the goal of increasing critical load supply. To mitigate the unbalanced current from three-phase AC loads, the use of flexible voltage source converter power control is emphasized. Furthermore, the original nonlinear model is linearized for tractability. The simulation results validate the merits of proposed MF method for improving the resilience of AC/DC hybrid distribution systems
Cohesive zone modelling of mesoscale thin ply bridging in CFRP composites
No full textFibre bridging is a phenomenon which resists crack propagation during Mode I fracture toughness (GIC) tests of Fibre Reinforced Polymer (FRP) composite materials, causing an increased demand for energy with increasing crack extension. Ply bridging, where the entire ply locally bridges the propagating crack, has not been studied for its toughening effects. A thin Spread Tow (ST) Uni-directional (UD) tape (32 g/m2) is applied to the mid-plane of a Carbon Fibre Reinforced Polymer (CFRP) composite laminate to induce ply bridging. This stochastic generation of ply bridging increased the Mode I fracture toughness at initiation and propagation by 118.8 % and 126 % respectively, compared to the control, which is a non-ST UD interface, with an areal weight of 150 g/m2. Both interfaces were modelled using a bi-linear softening law embedded in the cohesive elements during cohesive zone modelling. Excellent agreement in terms of force–displacement behaviour, peak force, crack front shapes taken from micro-CT (micro-Computed Tomography) evaluation and also crack extensions were observed. This study highlights the possibility of this phenomenon to greatly increase the fracture toughness of CFRP composites by splitting the matrix-rich interlaminar region into two smaller planes surrounding the thin ply interleaf.<br/
Development of optimised basalt FRP macrofibre-reinforced concrete with evaluation of fresh, mechanical and durability performance
No full textThis paper investigates the properties of an emerging fibre-reinforced concrete (FRC) incorporating basalt fibre-reinforced polymer macrofibres (BFRPmf), as dispersed, non-metallic reinforcement. The study aimed to develop BFRPmf-reinforced concrete (BFRPmfRC or BmfRC) with optimised fresh, mechanical, and durability performance by evaluating three BFRPmf types at four volume fractions (Vf = 0.25%, 0.5%, 0.75%, 1%) in a self-compacting concrete (SCC) matrix, yielding 12 mixes. Fresh properties were assessed using slump flow, V-funnel, and J-ring tests. Hardened mechanical properties were measured through compressive strength, tensile splitting strength, and direct (uniaxial) tensile tests (DTT). Durability indicators included volume of permeable voids (VPV), electrical resistivity (ER), and chloride migration coefficient (CMC). To capture full-range tensile behaviour without premature fracture, a tapered dog-bone specimen was designed for DTT, with strain monitored by digital image correlation (DIC). The 12 BmfRSCC mixes were benchmarked against a plain SCC reference. Results showed that BFRPmfs with higher slenderness and effective count reduced workability beyond 0.5% Vf but enhanced direct tensile strength by up to 70%. With homogeneous fibre dispersion, post-cracking ductility also increased, allowing tensile strains of 20–22%. Compressive strength remained within ± 10% of the reference. The optimal dosage, determined through analysis of variance (ANOVA), was 0.5% Vf, balancing rheological and mechanical behaviour. Flexural residual strength testing guided the selection of the most effective fibre type for structural trials. Durability results from tests on slab cores confirmed that, at optimal dosage, BFRPmf improved both mechanical and durability properties, highlighting its potential as a sustainable, corrosion-resistant alternative to steel reinforcement.<br/
Typology of online mental health peer support for young people: a systematic scoping review
No full textBackgroundYoung people are the age group with the highest prevalence of mental health problems, yet they are the least likely to engage with traditional treatments for their symptoms. Online peer support can support youth mental health as a supplementary strategy. While there is a growing body of research focusing on specific forms of online peer support and their effectiveness, a clear classification of the types of online peer support is under-developed.ObjectiveThe aim of this systematic scoping review was to identify and synthesise the existing peer-reviewed literature on online mental health peer support for young people to better understand the main characteristics of online peer support and develop a possible typology.MethodsThe IBSS, SSCI, Scopus, PsycINFO, Medline and Social Policy and Practice databases were searched using title and abstract. Retrieved studies (n = 12,093) were double screened and 49 articles met the criteria to be included in the review.ResultsThe systematic scoping review identified seven main characteristics and twenty-two sub-characteristics of online peer support. Based on those characteristics, three key distinguishing characteristics were identified which enabled a typology to be developed. It was therefore found that online peer support for youth mental health could be categorised into eight main types.ConclusionsThe identified characteristics and typology provide an overall description of current online mental health peer support for young people. This typology can facilitate research on effectiveness and further developments in online peer support. It may also help young people explore the types of online support available to them. Further research should explore the mechanisms and effectiveness of online peer support.<br/
Thermodynamics of coupled time crystals with an application to energy storage
No full textOpen many-body quantum systems can exhibit intriguing nonequilibrium phases of matter, such as time crystals. In these phases, the state of the system spontaneously breaks the time-translation symmetry of the dynamical generator, which typically manifests through persistent oscillations of an order parameter. A paradigmatic model displaying such a symmetry breaking is the boundary time crystal (BTC), which has been extensively analyzed experimentally and theoretically. Despite the broad interest in these nonequilibrium phases, their thermodynamics and their fluctuating behavior remain largely unexplored, in particular for the case of coupled time crystals. In this work, we consider two interacting BTCs and derive a consistent interpretation of their thermodynamic behavior. We fully characterize their average dynamics and the behavior of their quantum fluctuations, which allows us to demonstrate the presence of quantum and classical correlations in both the stationary and the time-crystal phases displayed by the system. We furthermore exploit our theoretical derivation to explore possible applications of time crystals as quantum batteries, demonstrating their ability to efficiently store energy
Tracing the global origins of black tea using rapid XRF techniques coupled with advanced machine learning
No full textHaving robust traceability of black tea is important to help prevent tea fraud. Developing rapid, accurate, environmentally friendly, and user-friendly methods to distinguish the geographical origins of black tea, is of great significance for safeguarding geographic indication (GI) products. In this study, the elemental contents of 791 authentic black tea samples from ten major tea-producing regions worldwide were quantified using X-ray fluorescence spectroscopy. The concentration of 15 elements in tea products was measured, and the characteristic elemental profiles for the ten GI regions were established. In addition, two unsupervised analysis techniques were used to visualize high-dimensional data, and six supervised models were employed to discriminate the ten GI regions. The results show that the machine learning models, including random forest, support vector machine, k-nearest neighbours, linear discriminate analysis, and the deep learning multilayer perceptron (MLP) model, demonstrated superior predictive capabilities compared to the traditional partial least squares discriminant analysis model, with the F1 score of identifying Assam tea improved from 66.1 % to a range of 87–97.7 %. The MLP model achieved the highest performance, with a 97.7 % overall F1 score in predicting the geographical origins of 532 authentic samples across ten GI regions. This research lays the foundation for establishing a comprehensive global black tea traceability system which has major implications for preventing tea fraud worldwide.<br/
Immune cell subsets in young kidney transplant recipients: mechanistic and clinical perspectives
No full textKidney transplantation provides the best survival advantage for children, adolescents, and young adults with end-stage kidney disease, yet this group paradoxically experiences the poorest long-term graft survival. Immune-mediated rejection is the predominant cause, but the cellular mechanisms that underpin this age-related disparity remain incompletely defined. This review synthesises current evidence on the impact of immune ageing across adaptive and innate compartments, focusing on T cells, B cells, and natural killer (NK) cells. In younger recipients, a large naïve T- and B-cell pool, robust thymic output, and efficient germinal centre activity confer heightened alloimmune reactivity, driving increased risk of acute cellular and antibody-mediated rejection. In contrast, older recipients exhibit features of immunosenescence, including loss of CD28 expression, accumulation of terminally differentiated effector subsets, impaired germinal centre responses, and attenuated NK cytotoxicity, resulting in diminished capacity to mount de novo responses but greater vulnerability to infection. These immune trajectories have direct clinical implications: younger recipients may require intensified, mechanism-targeted immunosuppression, whereas older recipients may be more amenable to minimisation or tolerance protocols. We further highlight emerging evidence for premature immunosenescence in paediatric dialysis populations, the contribution of age-associated B cells and NK subsets, and the role of immunophenotype-guided therapeutic strategies. Current uniform immunosuppression protocols inadequately account for developmental and age-related immune heterogeneity. We argue for an age- and immune phenotype–informed approach to therapy, integrating longitudinal immune profiling, biomarker development, and systems immunology to improve risk stratification, promote tolerance, and ultimately extend allograft survival across all age groups.<br/
Irish Catholic writers and the Gothic. Situating Thomas Furlong's The Doom of Derenzie (1829)
No full textTracing the global origins of black tea using rapid XRF techniques coupled with advanced machine learning
No full textHaving robust traceability of black tea is important to help prevent tea fraud. Developing rapid, accurate, environmentally friendly, and user-friendly methods to distinguish the geographical origins of black tea, is of great significance for safeguarding geographic indication (GI) products. In this study, the elemental contents of 791 authentic black tea samples from ten major tea-producing regions worldwide were quantified using X-ray fluorescence spectroscopy. The concentration of 15 elements in tea products was measured, and the characteristic elemental profiles for the ten GI regions were established. In addition, two unsupervised analysis techniques were used to visualize high-dimensional data, and six supervised models were employed to discriminate the ten GI regions. The results show that the machine learning models, including random forest, support vector machine, k-nearest neighbours, linear discriminate analysis, and the deep learning multilayer perceptron (MLP) model, demonstrated superior predictive capabilities compared to the traditional partial least squares discriminant analysis model, with the F1 score of identifying Assam tea improved from 66.1 % to a range of 87–97.7 %. The MLP model achieved the highest performance, with a 97.7 % overall F1 score in predicting the geographical origins of 532 authentic samples across ten GI regions. This research lays the foundation for establishing a comprehensive global black tea traceability system which has major implications for preventing tea fraud worldwide.<br/