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Validation of a data-driven multi-ancillary services framework for photovoltaic/storage units via power hardware-in-the-loop testing
Get PDFThis paper presents the experimental validation of a unified multi-ancillary services (AS) architecture for distributed photovoltaic–battery energy storage (PV-DBESS) systems using power hardware-in-the-loop (PHiL) testing. The focus is on voltage regulation (VR) and voltage unbalance mitigation (VUM), with full decoupling between the two control schemes to ensure interference-free operation. Experiments are conducted on a small-scale distribution network using a hybrid PHiL setup that combines real-time simulation with physical hardware, bridging the simulation-to-practice gap. A detailed three-phase four-leg converter model with embedded VR and VUM algorithms is implemented in RSCAD, and simplified controllable current source models are also evaluated to balance computational efficiency with accuracy. The results demonstrate that the proposed control strategies effectively mitigate overvoltage and unbalance events across varying operating conditions and network characteristics. The VUM scheme leverages reactive power through virtual damping susceptances, while the VR scheme coordinates active and reactive power to regulate the positive-sequence voltage. Interoperability with conventional constant-power converters is also verified. The study confirms that the proposed AS architecture provides a robust and practical solution for enhancing reliability and hosting capacity in active distribution networks, while indicating its potential suitability for future large-scale real-time studies and integration with advanced grid operation systems, particularly through the use of simplified converter models
Medicago sativa responses to PAH-contaminated soils amended with leaf biomass : growth and stress biomarker assessment
Get PDFPolycyclic aromatic hydrocarbons (PAHs) are persistent soil contaminants that induce plant stress. This study assessed how leaf-biomass amendments affect growth and stress-biomarker profiles in Medicago sativa exposed to PAH-contaminated soils. Soils were spiked with 100 mg kg⁻¹ pyrene and phenanthrene and amended with 10%, 30%, or 70% (w/w) leaf biomass, sand + 30% amendment, contaminated-only, and non-contaminated controls. After 30 days of soil incubation, residual PAHs were quantified. Subsequently, alfalfa was grown for 4 weeks, and plant vigor, photosynthetic pigments, oxidative stress biomarkers, antioxidant enzyme activities, and nutrient uptake were assessed. PAH dissipation was clearly amendment dependent. The 10% amendment was most effective (18.9 ± 5.85 mg kg⁻¹; 81.10% reduction), followed by 30% (33.01 ± 4.92; 66.99%), 70% (39.40 ± 8.05; 60.60%), and sand + 30% (58.10 ± 4.56; 41.90%). The unamended contaminated soil retained its full load (~ 100 mg kg⁻¹) as it was not subjected to incubation, whereas the background control declined from 2.82 to 0.50 mg kg⁻¹ (82.27% reduction) by natural attenuation. Plant vigor mirrored these trends, highest in controls and lowest in contaminated soil. Stress symptoms included chlorophyll-a depletion, lipid peroxidation, and accumulation of reactive oxygen species (ROS), including hydrogen peroxide (H₂O₂) and superoxide anion (O₂•⁻). Antioxidant defenses—comprising catalase (CAT), which decomposes hydrogen peroxide into water and oxygen; ascorbate peroxidase (APX), which detoxifies hydrogen peroxide via the ascorbate–glutathione cycle; and phenolic compounds, which contribute to non-enzymatic ROS scavenging—were upregulated but insufficient to fully counter oxidative damage. Leaf biomass amendments—particularly at 10%—significantly enhanced PAH dissipation, reduced oxidative stress, and maintained physiological function in M. sativa. These findings support the potential use of leaf residues as low-cost organic inputs for sustainable phytomanagement and highlight M. sativa as a sensitive bioindicator for assessing soil quality in PAH-affected systems
Narrow-spectrum drug repurposing : targeting Gardnerella vaginalis biofilms associated with bacterial vaginosis
No full textAim: Bacterial vaginosis (BV) is the most common vaginal disorder in women of reproductive age. Current therapies are limited by poor activity against biofilms and high recurrence rates (>50%), demonstrating that new antimicrobials are required. Drug repurposing is an attractive approach for the discovery of new antimicrobials, so we aimed to screen repurposed libraries for activity against the key BV pathobiont Gardnerella vaginalis. Methods and results: Two drug libraries from Medicines for Malaria Venture comprising 640 compounds were screened against G. vaginalis and various Lactobacilli species. Initial screening identified 16 G. vaginalis-selective compounds, of which 10 showed ≥90% inhibition of planktonic growth while sparing Lactobacillus crispatus. Subsequent assays revealed that three candidates displayed activity against pre-formed G. vaginalis biofilms; MMV1634360 (an antiproliferative compound with reported anticancer and antifungal activity), MMV1582487 (originally developed as an Escherichia coli aminopeptidase N inhibitor), and MMV1582497 (a thymidylate kinase inhibitor developed for Mycobacterium tuberculosis). All three produced >2-log reduction in viable cell counts at 10 µM (P 4log10 CFU/ml reduction in viable cell counts at 10 µM (P < 0.001), and synergy with existing antibiotic therapy. Conclusions: We demonstrate that MMV1582487 is a selective, non-cytotoxic, anti-biofilm candidate against G. vaginalis, supporting its potential as a novel therapeutic option for BV
Assessing the performance of rolled vs machined Isogrid structures : microstructural characterisation and mechanical properties
Get PDFIsogrid is a lattice reinforced sheet structure with a proven track-record for improving the mass efficiency of sheet metal components. The isotropic and mass efficient mechanical properties of Isogrid suit a wide range of applications from the aerospace sector to construction. While replacing flat sheet metal with Isogrid has a high potential impact for the reduction of metal usage globally, current production methods (primarily CNC milling of thick plate) are not viable at mass manufacturing scale. Consequently, a novel method has been proposed to enable high volume production of Isogrid via rolling. However, rolling structures with non-constant or periodic cross sections is unorthodox, and the potential effects on the mechanical properties of Isogrid remains unknown. Herein, it is shown that rolling AA1050 into an Isogrid form improves its bending strength by 20% and tensile strength by 15% compared to machining for the same geometry with a more isotropic distribution of mechanical properties. These results demonstrate that rolling is a viable method for Isogrid production at scale and may enable greater resource efficiency in the domain of sheet metal manufacturing and construction
A bound-preserving and conservative enriched Galerkin method for elliptic problems
No full textWe propose a locally conservative enriched Galerkin scheme that preserves the physical bounds for an elliptic problem. To this end, we use a substantial over-penalization of the discrete solution’s jumps to obtain optimal convergence. To avoid the ill-conditioning issues that arise in over-penalized schemes, we introduce an involved splitting approach that separates the system of equations for the discontinuous solution part from the system of equations for the continuous solution part, yielding well-behaved subproblems. We prove the existence of discrete solutions and optimal error estimates, which are validated numerically
Numerical simulation-based collision risk assessment of autonomous underwater vehicles during launch and recovery
Get PDFThis paper presents a model for assessing collision risk during the launch and recovery (L&R) of Autonomous Underwater Vehicles (AUVs), aiming to provide auxiliary information to operators. The study focuses on a specific type of AUV side crane Launch and Recovery System (LARS), investigating the nonlinear coupling interactions among the ship, cable, and AUV motion under irregular wave conditions. A dynamic model of LARS is developed, considering factors such as seawater resistance and cable length variations. The motion of the AUV under different sea conditions is calculated and analyzed. A collision-probability estimation model for L&R is formulated from extrapolated AUV dynamic responses. Based on the Bernoulli trial principle, the collision probability is calculated through batch simulation, and the half-width of the confidence interval and the chi-square statistic are computed to assess the accuracy and stability of the results. Finally, the collision probabilities of different dynamic models of the LARS are analyzed and compared, and a risk assessment is conducted in accordance with DNVGL-RP-N103. The results provide a basis for evaluating the feasibility of AUV L&R operations under different sea conditions. This basis serves as auxiliary information for LARS operators of AUV, helping to make decisions during operation
Bright electron bunches from a plasma-wakefield accelerator with a steep density down-ramp
Get PDFHigh-brightness electron bunches drive fundamental research in particle physics and photon science. Key to achieving a high brightness is to have a low transverse emittance, which ensures that the bunch can be tightly focussed. In radiofrequency accelerators a low initial emittance can be rapidly degraded due to space charge forces, which are greatly diminished once the electron bunch attains a relativistic velocity. A plasma accelerator can maintain orders-of-magnitude higher accelerating fields than radiofrequency accelerators, while multiple techniques exist to create a low emittance electron bunch directly inside the plasma accelerator structure. Plasma accelerators therefore offer a possibility to create high-brightness bunches in wakefields driven even by low-quality drive bunches. Here we demonstrate the injection and gigavolt-per-metre acceleration of electron bunches with mm-mrad normalised emittance, O(10 pC/MeV) spectral density and per-cent-level energy spread, all with excellent reproducibility
An assessment of a dual-rotor wind turbine system and the implications of rotor phasing
Get PDFThe increased demand for clean renewable energy requires innovative technology designs. A dual-rotor wind turbine system is presented and modelled using Blade Element Momentum Theory. Four different rotor configurations were analysed in both structural loading and vibrational impact. A key advantage of the dual-rotor approach is its ability to maintain partial operation even if one rotor fails, a feature that could significantly increase wind farm reliability. The study explores contra-rotation as a strategy to mitigate asymmetric lateral loads, thereby reducing torsional and rolling stresses at the tower and beam locations - a critical factor for structural longevity. This investigation analysed the impact of rotor phasing, an area previously unaddressed in the literature, by focusing on system dynamics in both frequency and time domains. Our findings reveal that operating the rotors out of phase can reduce fore-aft vibrations in the connecting beam by up to 86%, without increasing overall structural loads
Assessing digital preservation training needs in cultural heritage institutions in Saudi Arabia
No full textIntroduction We discuss an investigation into the digital preservation training needs of Saudi Arabia’s cultural heritage institutions. In countries where digital preservation is in its infancy, such as Saudi Arabia, assessing training needs is vital to provide training programmes tailored to digital preservation specialists’ distinctive needs. Method An exploratory qualitative case study design was chosen, involving selected managers and practitioners from relevant cultural heritage institutions in Saudi Arabia. In this paper we report on the online survey with staff members at King Abdulaziz Foundation for Research and Archives (Darah), King Abdul Aziz Public Library, King Fahad National Library, Saudi National Centre for Archives and Records, Makkah Centre for Archives and Records, King Abdullah University Library. Analysis Data from 37 survey respondents were analysed using the statistical package SPSS and Braun and Clarke’s six steps for thematic analysis; NVivo software was used to assist with coding and themes development. Results The research highlights factors supporting training needs and skill enhancement in digital preservation training practices in Saudi Arabia cultural heritage institutions. Findings help fill a regional gap in a predominantly Western-centric literature on digital preservation training, and offer insights for cultural heritage information management and international digital humanities research. Conclusion To safeguard long term digital preservation of cultural heritage, training needs of digital preservation specialists in Saudi Arabia and beyond must be adequately addressed, planned for, financially and institutionally supported, adequately communicated, and promoted
Electrochemical screening of synthetic cathinone metabolites
Get PDFSynthetic cathinones (SCat) constitute the second largest class of emerging novel psychoactive substances (NPS) which are continuing to increase in prevalence in recent years. Their recreational use, as psychostimulants with hallucinogenic effects, represent a significant public health problem. However, the variety and number of new SCats means forensic detection is extremely challenging. This is particularly true of toxicological and/or emergency room samples, where their metabolites need to be detected. Therefore, there is a necessity for rapid, portable, robust and easy to use screening methods to tackle this issue. This contribution explores the use of square wave voltammetry (SWV) as a proof-of-concept for screening of three SCat metabolites, namely 3,4-catechol-PV (also known as 3,4-dihydroxypyrovalerone or 3,4-DH-PV) (3,4-catechol-PV), β-OH-α-pyrrolidinopentiophenone (β-OH-α-PVP) and nor-mephedrone (Nor-MEP). These are metabolites of mephedrone (MEP), α-pyrrolidinopentiophenone(α-PVP) and 3,4-methylenedioxy pyrovalerone (MDPV). This approach could be successfully deployed at crime scenes or within emergency rooms for rapid, low cost screening of biological samples for the presence of SCat metabolites. This approach highlights their detection in ideal buffered solutions as well as artificial biological matrices demonstrating its feasibility for the screening of toxicological samples and illustrates a simple and reliable screening method over the micromolar concentration range with a limit of detection of ∼1 μM for each metabolite in buffer and artificial biological matrices
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