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Item Open Access Context-aware Data Driven Sensor Data Analysis: With Application to H2S Concentration Prediction in Urban Drainage Networks(Elsevier, 2025-05-02) Duque, Hector Castro; Diao, Kegong; Villa, Raffaela; Leitao, Joao Paulo; Djordjević, Slobodan; Abdel-Aal, MohamadThis paper presents a context-aware data-driven approach for the analysis of big data from sensors. Different from conventional methods, this approach incorporates exogenous variables or contextual information that influences the dynamic behaviour of the monitored system. In the context of water distribution systems, for example, key system variables including water demand variations and pressure are significantly affected by factors like time of day, the day of the week, unusual events, seasonal variations and weather conditions. This contextual information creates dynamic relationships between water demand and pressure, which are critical for understanding system behaviour. Specifically, the context-aware method will use present and past observed values from sensors (which are normally time-series data recording the system’s dynamic behaviour), in addition to also including contextual information regarding the spatial context (e.g., the correlation between the values of different sensors) and temporal context (e.g., correlation between observed values and days of the week and time of the day). The method is applied to the prediction of Hydrogen Sulphide (H2S) concentration in a real-world urban drainage network, based on the analysis of big real-time data sets from different sensors. Although the datasets are variables with non-uniform time intervals, uncertainties, and faulty data, the context-aware method identifies the correlations among different datasets to predict the concentration of H2S with high accuracy (R2 > 0.92; RMSE = 0.029). The method is also proven robust for a Deep Neural Networks approach.Item Metadata only Introduction to advances in emerging thermoelectric materials and devices(Royal Society of Chemistry, 2025-04-25) Manjunatha, Krishna Nama; Paul, Shashi; Sahu, Satyajit; Zebarjadi, MonaDue to the growing global energy demand and the increasing adoption of sustainable and clean energy solutions, research in thermoelectric generators (TEGs) has intensified, leading to the development of novel materials that are earth-abundant, non-toxic, and produced at low cost. The direct conversion of heat into electricity is enabled by thermoelectric materials, which have gained significant attention because of their potential for clean energy harvesting. TEGs have recently gained popularity mainly due to their simple device structure and operation, being lightweight, noise-free and solid-state (there is no ongoing maintenance as there are no moving parts), and the possibility to integrate them with various devices that produce heat as a by-product. The performance of TEGs is determined by the dimensionless thermoelectric figure of merit (ZT).Item Metadata only Validation of a meso-scale Urban Building Energy Model of domestic heat demand in England and Scotland(Building Digital Twin Scientific Conference 2025, 2025-04-30) Bustamante, Javier Sandoval; Khattak, SanoberThis article presents a methodology to model domestic peak heating load and annual heat demand at the urban scale using geospatial data and building stock data from Energy Performance Certificates (EPC). The model was run on 720269 domestic properties across three different local authorities in Scotland (Aberdeen City, Dundee City Council and Fife) and two combined authorities in England (Somerset Council and West Midlands Combined Authority). Then, the results were validated on a mean absolute percentage error (MAPE) basis against smart meter gas demand readings from 4397 properties included in the Smart Energy Research Lab (SERL) Statistical data set. The model was able to predict peak heating load with a 4% MAPE in F-rated properties in Fife and annual heat demand with a 6% MAPE in A-rated properties in Somerset Council. However, the reported MAPE goes as high as 70% for peak heating load and 57% for annual heat demand. Further validation on an aggregated basis is required against a comprehensive data set that includes separate gas demand readings for space and hot water heating.Item Open Access Surface Crack Analysis and Quality Enhancement of 30%13 (AISI 420) Martensitic Stainless Steel Gate Valve Shutters via Electrolytic Plasma Hardening(Elsevier, 2025-04-16) Kombayev, Kuat; Nedobitkov, Alexandr; Gridunov, Ivan; Kozhakhmetov, Yernat; Khoshnaw, Fuad; Aibar, KizatovThis study examines the mechanisms of crack formation in gate valve shutters, identifies the underlying causes, and proposes an effective prevention method through electrolytic plasma surface treatment technology. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) with a JSM-6390LV SEM were used to evaluate the chemical composition, morphology, structure, and surface defects of the shutters at nano- and microscale levels. To assess mechanical properties, Vickers microhardness testing (ISO 6507-1) was conducted using a DuraScan 20 microhardness tester, while the phase composition of 30Х13 steel (AISI 420) was examined through X-ray diffraction (XRD) analysis. The results demonstrate a significant increase in surface microhardness in samples subjected to electrolytic plasma hardening, with values reaching up to 650 HV. Furthermore, the phase composition of the treated surface exhibited notable changes, including the dissolution of carbides in austenite and the formation of martensite as the predominant phase. Based on these findings, electrolytic plasma hardening is proposed as an effective alternative to traditional volumetric quenching methods. An optimal treatment mode has been developed for 30 × 13 steel, ensuring enhanced surface properties and improved durability. The experimental results validate the effectiveness of this approach in enhancing the mechanical performance and operational reliability of gate valves.Item Open Access Microplasma Sprayed Tantalum Coatings on Ti Grade 5 Extra-Low Interstitials: Investigation of Thickness and Porosity Control(MDPI, 2025-04-15) Kombayev, Kuat; Khoshnaw, Fuad; Kozhakhmetov, Yernat; Tleuzhanova, Gulnur; Azamatov, Bagdat; Tabiyeva, YerkezhanThis study investigates the microplasma deposition of molten tantalum (Ta) onto a rotating Grade 5 Ti Extra-Low Interstitial (ELI) alloy, producing multilayer film coatings with a porous microstructure. Optimal parameters for microplasma spraying Ta were experimentally determined to improve the surface properties of elbow joint implants. The physical and mechanical properties of the Grade 5 Ti ELI substrate and the Tabased coating were analyzed. Moreover, mathematical modeling was utilized to determine the optimal parameters for the plasma coating process, including key factors such as spray distance, current, and rotational speed, which were systematically applied across three experimental series. A Ta coating thickness of 250 μm was achieved at 35 A current, 410 mm spray distance, and 7 rpm rotation speed under optimized deposition conditions. The results showed a microhardness increase on the Ta-coated surface, peaking above HV1000 with an average of HV742, while the Ti substrate averaged HV325. Additionally, the XRD patterns revealed the presence of metallic Ta alongside Ta oxides, such as Ta2O and Ta2O5, in the Ta coatings.Item Open Access Smart Farming Solutions: A User-Friendly GUI for Maize Tassel Estimation Using YOLO With Dynamic and Fixed Labelling, Featuring Video Support(IEEE, 2025-03-26) Moshayedi, Ata jahangir; Wang, Zhonghua; Sharifdoust, Maryam; Sioofy Khoojine, Arash; Zhang, Wei; Kolahdooz, AminThe integration of Autonomous Aerial Vehicles (AAVs) has significantly advanced image processing and remote sensing, particularly in precision agriculture. These technologies enhance data collection and agricultural yield estimation, benefiting banks, insurance companies, and government agencies in decision-making for budget allocation and quality assessments. This study addresses the challenge of accurately quantifying corn production by developing an enhanced YOLO-v8-based deep learning model, incorporating dynamic and fixed labeling techniques, tested on 810 images and video data for real-time detection. The research utilized two primary datasets totaling 570 images. The evaluation process comprised four distinct tests: Test 1, conducted on Dataset 1 with 200 images, assessed seven attention mechanisms (SE, CBAM, GA, LKA, CA, SA, and TA) using deep learning metrics (Precision, Recall, mAP50, mAP50-95, F1-score) and statistical methods (Duncan’s test). Test 2 validated model performance on 370 images from external sources, where YOLO.SA achieved 97.48% accuracy, outperforming YOLO.LKA (95.13%). Test 3, comparing with the MTDC benchmark dataset, confirmed YOLO.SA’s accuracy at 95.93%, exceeding previous reports, while YOLO.LKA achieved 95.71%. Finally, Test 4, utilizing video-based evaluation via a developed GUI, demonstrated YOLO.SA’s superiority (95.77%) over YOLO.LKA (95.48%) and YOLO-v5 (95.72%), significantly outperforming the standard YOLO model (72.79%). This study advances computer vision in agriculture, offering a scalable, high-accuracy model for corn yield estimation, with broad applications in farming optimization, financial planning, and policy-making.Item Open Access Air Traffic Management and Communication over ATN/IPS for Future Datalink Communication(IEEE, 2025-04) Aydoğan, Emre; Özmen, Sergun; Cetek, Fulya Aybek; Arnaldo Valdés, Rosa María; Delgado-Aguilera Jurado, Raquel; Carmona Fernández, Ángel Ernesto; Martínez Miralles, Adrián; Vendruscolo, Tommaso; Bonelli, Stefano; Delahaye, Daniel; Chaimatanan, Supatcha; Chen, Feng; Hamzaoui, RaoufThe growing demand for air traffic presents challenges in air traffic management, making seamless gate-to-gate communication essential. Traditional radio frequency communication faces limitations such as weather dependency and frequency restrictions. To address these issues, data link communications have gained importance, using VHF channels, satellite systems, and ATN/IPS-based networks. This study introduces the ATMACA (Air Traffic Management and Communication Over ATN/IPS) protocol, an advanced context management framework for ATN/IPS, designed to enhance aviation communications. ATMACA integrates instant messaging and software-defined nodes to improve connectivity, session continuity, and mobility management across networks and devices. It ensures seamless user interaction, reduces pilot workload, and enhances flight safety through automated Air Traffic Control (ATC) sector handoff in Controller–Pilot Data Link Communications (CPDLC) and Data Link Initiation Capability (DLIC) applications. Another key innovation of the ATMACA framework is Green Route Operations (GRO), which enables real-time trajectory prediction and optimization.Item Open Access Modal Phase Study on Lift Enhancement of a Locally Flexible Membrane Airfoil Using Dynamic Mode Decomposition(MDPI, 2025-04-06) Kang, Wei; Hu, Shilin; Chen, Bingzhou; Yao, WeigangThe dynamic mode decomposition serves as a useful tool for the coherent structure extraction of the complex flow fields with characteristic frequency identification, but the phase information of the flow modes is paid less attention to. In this study, phase information around the locally flexible membrane airfoil is quantitatively studied using dynamic mode decomposition (DMD) to unveil the physical mechanism of the lift improvement of the membrane airfoil. The flow over the airfoil at a low Reynolds number (Re = 5500) is computed parametrically across a range of angles of attack (AOA = 4°–14°) and membrane lengths (LM = 0.55c–0.70c) using a verified fluid–structure coupling framework. The lift enhancement is analyzed by the dynamic coherent patterns of the membrane airfoil flow fields, which are quantified by the DMD modal phase propagation. A downstream propagation pressure speed (DPP) on the upper surface is defined to quantify the propagation speed of the lagged maximal pressure in the flow separation zone. It is found that a faster DPP speed can induce more vortices. The correlation coefficient between the DPP speed and lift enhancement is above 0.85 at most cases, indicating the significant contribution of vortex evolution to aerodynamic performance. The DPP speed greatly impacts the retention time of dominant vortices on the upper surface, resulting in the lift enhancement.Item Open Access Drivers and Preferences of European Farmers for Agri-Environmental Public Goods Schemes: A Two-Stage Analysis(Elsevier, 2025-03-28) Tyllianakis, Emmanouil; Will, Meike; Václavík, Tomáš; Ziv, GuyThe new Common Agriculture Policy (CAP) intends to give more freedom to countries to manage their budget while increasing funding for income support and provisioning of climate public goods from agriculture and farming. For the past 20 years this has been operationalised through incentivising farmers’ contract participation in agri-environmental schemes (AES). In this paper we examine through a two-stage approach, farmer preferences for contract characteristics in a multi-European country Discrete Choice Experiment (DCE) and the determinants of land enrolment in contracts. Overall, we find that longer contracts and high administrative burden decrease the probability of enrolling in a contract over the base levels while shorter contract length and provisioning of advisory support are desirable. Amongst all available contract options, converting arable to grassland options was by far the one that participants asked the most compensation for, across countries. We also find that past experience with agri-environmental schemes and socio-demographics have a strong and statistically significant effect on the percentage of land enrolled, while contract characteristics do not influence enrolment. Finally, we present some evidence of position-ordering effects affecting preferences for contracts and their characteristics but not influencing contract enrolment. Understanding the true cost incurred by farmers to implement AES is crucial for policymakers as failure to do so can make farmers ask for much higher compensation, per hectare, potentially to cover costs of transitioning to different types of farming or to incorporate financial risk by significantly altering their farm practices.Item Open Access A novel empirical model for vertical profiles of downburst horizontal wind speed(Wiley, 2024-01-22) Dang, Huixue; Xing, Guohua; Wang, Hailong; Harmanto, Dani; Yao, WeigangThis study proposes an empirical model for preliminary wind-resist design of downburst flow. Existing empirical models were compared with field data and found to underpredict horizontal wind speed below the height corresponding to the maximum radial velocity, due to the neglect of viscous effects and the evolution of vertical wind profiles along radial direction. To address these deficiencies, semi-empirical piecewise functions including wall shear effects in the local turbulent boundary layer and interpolation functions were proposed to improve the accuracy of existing models. The wind profile based on Coles' theory was found to agree well with field data, with the parabola interpolation function being the most desirable. Using the proposed method, the vertical profile of horizontal wind speed at different local radial locations can be predicted for wind resist design given the inlet wind speed of the downburst flow. Overall, this model improves upon existing empirical models and allows for more accurate wind-resist design.Item Open Access Experimental design for a novel co-flow jet airfoil(Springer, 2023-12-01) Jiang, Hao; Yao, Weigang; Xu, MinThe Co-flow Jet (CFJ) technology holds significant promise for enhancing aero-dynamic efficiency and furthering decarbonization in the evolving landscape of air transportation. The aim of this study is to empirically validate an optimized CFJ airfoil through low-speed wind tunnel experiments. The CFJ airfoil is structured in a tri-sectional design, consisting of one experimental segment and two stationary segments. A support rod penetrates the airfoil, fulfilling dual roles: it not only maintains the structural integrity of the overall model but also enables the direct measurement of aerodynamic forces on the test section of the CFJ air-foil within a two-dimensional wind tunnel. In parallel, the stationary segments are designed to effectively minimize the interference from the lateral tunnel walls. The experimental results are compared with numerical simulations, specifically focusing on aerodynamic parameters and flow field distribution. The findings reveal that the experimental framework employed is highly effective in characterizing the aerodynamic behavior of the CFJ airfoil, showing strong agreement with the simulation data.Item Open Access Wing Design Optimization and Stall Analysis with Co-flow Jet Active Control(AIP Publishing, 2024-04-25) Jiang, Hao; Yao, Weigang; Zheng, Boda; Xu, MinCoupled with Co-flow Jet (CFJ) technology, the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was utilized for the multi-objective combination optimization of an Optimized Co-flow Jet (OCFJ) wing, based on National Advisory Committee for Aeronautics (NACA) 6421. A high-precision numerical simulation using the Delayed Detached Eddy Simulation (DDES) model was performed on the optimized wing to investigate the three-dimensional flow separation characteristics after static stall. The stall improvement was investigated by adjusting the momentum coefficient of the injection. The results show that the optimized wing exhibits significant improvements in aerodynamic performance and corrected aerodynamic efficiency. At an angle of attack of 10◦, the average lift increased by 16.25% and the drag decreased by 27.23% compared to the CFJ6421 wing, while effectively addressing the problem of low modified aerodynamic efficiency of the CFJ wing at lower angles of attack. By utilizing higher momentum and improving the boundary layer control capability, flow separation is effectively suppressed, thus achieving the goal of stall recovery of the CFJ wing.Item Metadata only Smart faces: using communication strategies to optimize technical information flow in middle-out facilities management(Taylor and Francis, 2025-02-10) Stuart, Graeme; Tian, Ling; Ozawa-Meida, L.With rapid technological evolution, Energy Management Information Systems (EMIS) have improved energy and water consumption visibility and provided the ability to rapidly detect energy and water waste. However, their integration with facilities management has had little attention from researchers. This study explores the design and optimization of technical information flows between automated data analysis systems and human facilities management systems in a UK Higher Education Institution (HEI) case study. Semi-structured interviews were used to support the co-design of an intervention, based on the systematic integration of EMIS into existing facilities management systems. When the intervention was deployed, longstanding and previously unidentified issues were quickly highlighted and resolved, leading to significant savings. The study concludes that integrating EMIS and Computerized Maintenance Management Systems (CMMS) can enhance the efficiency of middle-out actors in reducing energy and water waste in facilities management. While near-real-time feedback and other technological solutions are effective, the findings highlight the importance of communicating technical information clearly through appropriate channels, as well as middle role challenges such as limited resources, high workloads, and insufficient senior management backing. As facilities management adapts to and integrates new technologies, its full potential can be realized through effective communication and feedback mechanisms.Item Open Access Advances in Gallium Oxide: Properties, Applications, and Future Prospects(Wiley, 2025-03-20) Ganguly, Swapnodoot; Nama Manjunatha, Krishna; Paul, ShashiThe traditional domination of silicon (Si) in device fabrication is increasingly infiltrated by state‐of‐the‐art wide bandgap semiconductors such as gallium nitride (GaN) and silicon carbide (SiC). However, the performance of these wide bandgap semiconductors has not yet exceeded the optical material limitation, which leaves ample room for further development. Gallium oxide (Ga2O3) has surfaced as the preferred material for next‐generation device fabrication, as it has a wider bandgap (≈4.5–5.7 eV), an estimated twofold greater breakdown field strength of 8 MV cm−1, and a higher Baliga's figure of merit(BFOM) (>3000) than SiC and GaN, therefore pushing the limit. In this review, the properties of gallium oxide, several methods for epitaxial growth, its energy band, and its broad spectrum of applications are discussed. Metals for achieving different types of contact and the influence of interfacial reactions are additionally assessed. Furthermore, defects and challenges such as p‐type doping, integration with heterostructures, the formation of superlattices, and thermal management associated with the use of this material are also reviewed.Item Metadata only Business models and access to finance for mini grid development in sub-Saharan Africa(Elsevier, 2025-02-18) Fajardo, Adriana; Baker, Lucy; Sesan, Temilade; Bhattacharyya, Subhes; Kerr, Daniel; Katyega, M; Barnett, AndrewDrawing from a comprehensive literature review of publications from academia, industry, government and international institutions, this paper presents a critical analysis of the different business models and modes of finance for mini grids in SSA, alongside the operational risks and challenges faced by these emerging systems. First, we investigate the different business models that currently exist for mini grids in SSA, providing insights into the opportunities and challenges of each approach. Second, we identify access to finance as a prominent challenge to the expansion of ‘third generation’ or solar/ solar-hybrid mini grids in the region. In so doing, we explore the different configurations of actors, institutions and processes involved in the provision of finance and investment. Third, we examine key investment, regulatory and operational risks and challenges to the sector's current and future development. Despite a notable growth in the deployment of solar and solar-hybrid mini grids in SSA and elsewhere, progress in bridging the rural electrification gap has been slow. More than 750 million people globally still lack access to electricity in the region, particularly in remote areas considered too poor to afford cost-reflective tariffs. As this paper argues, more clarity is needed between the enthusiasm expressed regarding the potential of mini grids and the level and quality of finance available for such systems. While the literature points to hybrid ownership, partially subsidised models, a focus on anchor customers, and the bundling of projects into financial portfolios as the most promising business strategies, we argue that there is no one-size-fits-all solution for mini grid business models in SSA. An optimistic narrative towards private sector participation may not always translate into greater accessibility and affordability, particularly for geographically remote and low-income users. While the mini grid sector in SSA has grown significantly in recent years, securing adequate and appropriate external finance remains a key challenge.Item Open Access Practical and Theoretical Optimization of Plasma Cutting Parameters for Enhanced Quality and Efficiency in Steel Alloy Processing(Emerald, 2025-02-25) Kombayev, Kuat; Sypainova, Gulden; Khoshnaw, Fuad; Kozhakhmetov, Yermat; Kurbanbekov, Sherzod; Tabiyeva, YerkezhanThis study determined the optimal plasma cutting parameters to enhance the quality and efficiency of steel alloy processing. Experiments were conducted on 6 mm thick 09G2S steel alloy using a Kawasaki RS-010L robotic manipulator with a DS 120P.33 inverter power supply. Practical findings revealed that a current of 50 A, voltage of 118 V, cutting speed of 3200 mm/min, and airflow of 1.9 x 10⁻³ m³/s provided the best results, producing a smooth surface, minimal burrs, and a cutting angle within approximately ±4° relative to the surface. The cross-section of the cutting surfaces was analyzed to study the chemical composition across different areas and assess variations caused by the cutting process. Taguchi method was used to find the optimal theoretical parameters, which showed the optimal parameters as 126 V for angle, 118 V for cutting width, 4400 mm/min cutting speed and airflow of 2.3×10−3 m3/s for angle (1.9×10−3 m3/s for cutting width). The microstructure analysis confirmed uniformity in meeting international standards. This research comprehensively analyses cutting conditions and their effects, benefiting metal fabrication by promoting cost-effective, sustainable processes.Item Open Access Effect of Geometry on the Dissolution Behaviour of Complex Additively Manufactured Tablets(MDPI, 2025-01-03) Afkhami, Seyedebrahim; Abdi, Meisam; Baserinia, RezaAdditive manufacturing (AM) processes, such as fused deposition modelling (FDM), have emerged as transformative technologies in pharmaceutical manufacturing, enabling the production of drug delivery systems with complex and customised geometries. These advancements provide precise control over drug release profiles and facilitate the development of patient-specific medicines. This study investigates the dissolution behaviour of AM-fabricated tablets made from polyvinyl alcohol (PVA), a hydrophilic and biocompatible polymer widely used in drug delivery systems. The influence of the initial mass, surface area, and surface-area-to-volume ratio (S/V) on dissolution kinetics is evaluated for tablets with intricate geometries. Our findings demonstrate that these parameters, while critical for conventional tablet shapes, are insufficient to fully predict the dissolution behaviour of complex geometries. Furthermore, this study highlights how geometric modifications can enable the administration of the same drug dosage through sustained or immediate release profiles, offering enhanced versatility in drug delivery. By leveraging the geometric design freedom provided by AM technologies, this research underscores the potential for optimising drug delivery systems to improve therapeutic outcomes and patient compliance.Item Open Access Manifold Learning for Aerodynamic Shape Design Optimization(MDPI, 2025-03-19) Zheng, Boda; Moni, Abhijith; Yao, Weigang; Xu MinThe significant computational cost incurred due to the iterative nature of Computational Fluid Dynamics (CFD) in traditional aerodynamic shape design frameworks poses a major challenge, especially in the context of modern integrated design requirements and increasingly complex design conditions. To address the demands of modern design, we developed an efficient aerodynamic shape design framework based on our previous work involving the locally linear embedding plus constrained optimization genetic algorithm (LLE+COGA) high-fidelity reduced-order model (ROM). An active manifold (AM) auto-en/decoder was employed to address the dimensionality curse arising from an excessively large design space. The fast mesh deformation method was utilized for high-precision, rapid mesh deformation, significantly reducing the computational cost associated with transferring geometric deformations to CFD fine mesh. This work addressed the transonic optimization problem of the undeflected Common Research Model (uCRM) three-dimensional wing (with an aspect ratio of 9), involving 241 design variables. The results demonstrate that the optimized design achieved a significant reduction in the drag coefficient by 38.9% and 54.5% compared to the baseline in Case 1 and Case 2, respectively. Additionally, the total optimization time was shortened by 62.6% and 57.7% in the two cases. Moreover, the optimization outcomes aligned well with those obtained from the FOM-based framework, further validating the effectiveness and practical applicability of the proposed approach.Item Metadata only Cities and Governance for Net-Zero: Assessing Procedures and Tools for Innovative Design of Urban Climate Governance in Europe(MDPI, 2025-03-18) Terwilliger, Joel; Christie, IanDespite the collective promise of integrating more open (broader-based, participatory) city-level governance into the global energy governance regime, little attention has been paid to the different impact logics and assumptions underpinning local procedural governance tools (PGTs) in circulation and the degree to which they address key good governance dimensions dominantly thought to be indicative of transformation. This review aims to fill this gap by mapping and analyzing key energy transition PGTs circulating across four climate action initiatives that mobilize and provide support to cities and local governments. A framework—REPAIR: Reflexivity, Enabling/Embedding, Participatory, Integrative, Adaptive, and Radicality—is proposed based on a synthesis of common governance innovation design features, and a representative sample of 25 PGTs are evaluated against these dimensions. The analysis reveals a need for (1) more differentiation and tailored capacity relating to governance monitoring, evaluating, and learning systems; (2) more attention to prioritization and design factors across different governance interventions in relation to local climate actions; and (3) more nuanced theories of change for operationalizing local power/coalition/mandate building (across different dimensions of governance). This article concludes that there are real gaps in how the collective advantages, opportunities, and promise of traveling “ideal types” of good governance will be fulfilled and outlines future research directions for informing more aligned governance innovation for low-carbon transitions in urban areas.Item Open Access Supplementation strategies to control propionic acid accumulation resulting from ammonia inhibition in dry anaerobic digestion: Osmoprotectants, activated carbon and trace elements(Elsevier, 2025-02-27) Rocamora, Ildefonso; Wagland, Stuart T.; Hassard, Francis; Villa, Raffaela; Peces, Miriam; Fotidis, Ioannis A.; Simpson, Edmond W.; Fernández, Oliver; Bajón-Fernández, YadiraPropionic acid accumulation in anaerobic digestion is a common sign of inhibition at high ammonia levels. To mitigate accumulation three supplementations were tested: osmoprotectants, trace elements and activated carbon. Activated carbon and osmoprotectants (MgCl2) achieved a 28 % increase in methane yield and a 3-fold reduction in hydrogen partial pressure compared with the control. Trace elements supplementation increased methane formation by 18 % without preventing instability. No supplementation avoided propionic accumulation, although MgCl2 delayed it. Activated carbon and MgCl2 supported proliferation of strict hydrogenotrophs, increasing microbial redundance with expected positive impacts on process resilience. Evidence beyond previous studies on the role of retention time as a control parameter of versatile archaea’s methanogenic pathway is also provided. As retention time is reduced, syntrophic acetate oxidising bacteria are washed out of the system, likely resulting from an increase in their doubling time with inhibitors accumulation, preventing hydrogenotrophic methanogenesis and supporting previous observations of Methanosarcina being forced to conduct acetoclastic methanogenesis. Longer retention times to accommodate longer doubling times or alleviation of inhibition with activated carbon and MgCl2 supported retention of syntrophic acetate oxidising bacteria, enabling strict hydrogenotrophic archaea to proliferate. These supplementations would allow operation of industrial scale ADs at shorter retention times and higher throughputs. Results suggest that osmoprotectants and activated carbon addition were linked to a reduction in archaea’s osmotic pressure and enhanced direct interspecies transfer, respectively, leading to increased methane formation despite propionic levels.