20505 research outputs found
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Drone pollution tracking in cities using recurrent proximal policy optimization learning
Get PDFFuture smart cities will need to monitor polluters that periodically or burst emit illegal gases that is harmful to the environment. Tracking these sources in cities that have building obstacles and variation wind vector fields is challenging. Traditional methods using gradient kernels and partial-swarm-optimisation may not be suitable when the emissions are intermittent and pollution concentrations maybe trapped in local pockets. As such, step size tuning becomes difficult to generalise in these variational dynamic pollution environments. Here, in this paper, we have developed a simulated urban pollution propagation environment, whereby a drone is scanning the environment for gradients to search and localise the source. We consider both proximal policy optimisation (PPO)-based reinforcement learning and its recurrent PPO (R-PPO) alternative to achieve stable and reliable improvement of policy without the need to fine tune step sizes. We show localisation results across a range of wind, obstacle, and emission scenarios with success rate of 76-79% and high path efficiency of 95-96% in ideal conditions. When we examine alternative city structures and burst emissions, we can achieve success rate of 34% and path efficiency of 52%, showing that there is some generalisation in capability.This work is partially supported by EPSRC TAS-S: Trustworthy Autonomous Systems: Security (EP/V026763/1).2024 IEEE International Smart Cities Conference (ISC2
Understanding organic carbon dynamics in a river catchment through improved sediment fingerprinting
Get PDFAgricultural practices accelerate the rates of soil erosion and organic carbon (OC) loss, increasing the input of nutrient rich sediment to surface waters. As climate change is increasing the frequency and intensity of hydrological disturbances that drive erosion, it is of vital importance to quantify the terrestrial to aquatic fluxes of OC to inform sustainable management strategies and mitigate the impacts of soil OC loss in river catchments. In this study, OC sediment fingerprinting was used to determine seasonal sources of sediment to a freshwater stream from different land uses in a river catchment. Multiple lines of evidence (soil and stream sediment sampling, local climate and agronomic data) were used to evaluate tracer properties and sources in order to improve the sediment fingerprinting technique. Within a mixed land-use catchment, four potential sources of sediment (arable, forest, pasture and moorland) were characterised between June 2018 and December 2019. Spatio-temporal differences in OC sources were observed at different times of year. Arable soil was the dominant contributor to suspended sediment OC, ranging from 37% to 61% at the catchment outlet. Increased rainfall, discharge, livestock poaching, and bare or sparsely vegetated areas were found to be the drivers of change in seasonal sources of sediment relative to land use. This study demonstrated a holistic approach to inform sustainable catchment management; using multiple lines of evidence to improve the characterisation of sediment sources and highlight remaining uncertainties in the sediment fingerprinting technique.This work was supported by the Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council (Grant number NE/ M009106/1) through a studentship award to CW by STARS (Soils Training And Research Studentships) Centre for Doctoral Training and Research Programme.CATEN
Enhancing wave energy conversion in oscillating water column devices using breather valve-based pneumatic regulation: a CFD study
No full textThis study investigates the hydrodynamic and energy conversion performance of a cylindrical oscillating water column (OWC) device integrated with a breather valve for bidirectional pneumatic regulation. The primary objective is to suppress peak power output under high wave conditions and reduce the required generator rated capacity, thereby improving the load factor and operational efficiency during normal wave conditions. A three-dimensional computational fluid dynamics (CFD) is developed to simulate steady-state and transient flow characteristics, incorporating the nonlinear behavior of the breather valve. Parametric analyses are conducted to evaluate the effects of valve threshold pressure (3–12 kPa) and opening ratio (1 %–6 %) under regular wave conditions. Results reveal that the valve's pressure and flow regulation capabilities increase with the opening ratio, though this effect gradually saturates. Moreover, for a given threshold, a minimum opening ratio is required to achieve stable pressure relief, which decreases with increasing threshold pressure. The optimal configuration (3 kPa threshold with 5 % opening ratio) achieves substantial performance improvements compared to a conventional OWC without a breather valve. Specifically, the rated generator capacity is reduced by 87 % (from 740 kW to 100 kW), average generator efficiency increases by 50 % (from 60.8 % to 90.9 %), and average wave-to-electricity conversion efficiency improves by 46 % (from 10.3 % to 15 %). Additionally, annual energy production increases by 43 %, from 83,000 kWh to 119,000 kWh. These findings highlight the breather valve's effectiveness in stabilizing pneumatic power output and enhancing the overall efficiency of OWC systems.This work is supported by National Natural Science Foundation of China (Grant No. 52201349, 52571326), Guangdong Basic and Applied Basic Research Foundation (Grant No. 2023A1515012224, 2023B1515040028), and the Royal Society (IEC∖NSFC∖223253).Energ
Field-deployable wastewater sensors for public health
No full textA sustainable early warning monitoring system can overcome key limitations of conventional approaches for managing infectious diseases and epidemics. It enables consistent monitoring of pathogens, including SARS CoV-2, in wastewater treatment plants (WWTPs). Wastewater-based epidemiology (WBE) analyses biological markers excreted in sewage to monitor community health. It has emerged as a powerful tool because it is cost-effective, non-invasive, and capable of detecting pathogen circulation within the population, even before clinical cases are reported [1]. These features provide WBE a clear advantage over traditional clinical testing, particularly by enabling the early detection of new variants [2].Natural Environment Research Council (NERC)This work was supported by the UKRI NERC Fellowship (NE/R013349/2), the UKRI NERC N-WESP (NE/V010441/1), the NERC Innovative Sensing (NE/Z503538/1), and the Leverhulme Trust Research Leadership Awards (RL-2022-041).National Science Ope
Resilient interorganizational culture in multi-tier supply networks: the “what” and “how”
No full textPurpose
Highlighted in multiple calls, research on interorganizational culture remains limited in the supply chain resilience (SCRES) literature, particularly at the supply network-level. Drawing from an in-depth case study of a US-based chemical multinational and 21 multi-tier suppliers facing the COVID-19 disruption, this paper explores interorganizational culture’s role in SCRES in a multi-tier supply network. Based on the case data, this work proposes an exploratory definition of resilient interorganizational culture, conceptualizing it as a network-wide cultural alignment framework that can strengthen SCRES through cultural propagation and transitivity mechanisms.
Design/methodology/approach
The case consists of 83 in-depth interviews over nine months, collecting data from a buyer and 21 suppliers in the chemical industry. Using balance theory, the analysis examines what and how interorganizational culture elements influence the SCRES elements of collaboration, flexibility, visibility and velocity in a disrupted multi-tier supply network.
Findings
The case study sheds light on the various cultural elements and supply network mechanisms between organizations that form a resilient interorganizational culture during a significant global disruption. These cultural elements encompass shared goals, expectations, understanding, processes and values. The findings of this study indicate that these cultural elements, along with the mechanisms of network-level cultural propagation and cultural transitivity in balanced and unbalanced triadic cultural relationships, affect different aspects of SCRES uniquely. The study underscores the significance of evaluating the interorganizational cultural alignments existing in supply networks to achieve SCRES.
Originality/value
This paper maps aligned and misaligned cultural elements and explores how they characterize a resilient interorganizational culture in a multi-tier supply network, drawing on the concepts of network-level cultural propagation and transitivity in balanced and unbalanced triadic relationships. It extends balance theory by introducing cultural transitivity as a mechanism linking triadic cultural structures to resilience outcomes. It complements balance theory by conceptualizing cultural propagation as the diffusion of cultural alignments and misalignments beyond triads, influencing resilience at the network-level. It contributes to network theory by articulating how cultural alignments and misalignments flow both directionally and transitively across interconnected supply chain actors. Grounded in a single case study, the work advances SCRES theory by offering exploratory insights into how cultural transitivity and propagation enable the SCRES elements of collaboration, flexibility, visibility and velocity.Supply Chain Management: An International Journa
Sustainable prosthetic manufacturing: a comparative life cycle assessment of centralized and decentralized additive manufacturing supply chains in Europe
No full textThe conference proceedings will be published by Springer as book chapters in a volume of the KES Smart Innovation Systems and Technologies series.Additive Manufacturing (AM) has emerged as a transformative ap-proach in prosthetic fabrication, offering personalized healthcare solutions along-side potential environmental advantages. This study investigates the environmen-tal sustainability of centralized and decentralized AM-based supply chains for prosthetic production across Europe. Utilizing a Life Cycle Assessment (LCA) framework and cradle-to-gate methodology, the analysis quantifies carbon foot-print (CFP) and water footprint (WFP) across raw material acquisition, manufac-turing, and transportation stages. Geospatial data from Google Maps and Great Circle Map were employed to model distribution routes within four European regions centered on Luxembourg.
Centralized production was found to consistently outperform decentralized configurations in terms of environmental efficiency, largely due to reduced trans-portation-related emissions and resource use. In contrast, decentralized models, while offering increased responsiveness and customization, demonstrated ele-vated CFP and WFP values, particularly in regions with limited supplier accessi-bility or reliance on multimodal transport.
By revealing the trade-offs between supply chain configurations, this study contributes to the development of sustainable manufacturing practices in healthcare. The findings underscore the importance of strategic supply chain de-sign, material selection, and integrated LCA in aligning AM processes with cir-cular economy principles and global sustainability goals.12th International Conference on Sustainable Design and Manufacturing, SDM-202
Chapter 1: the archaeology of rivers: processes and patterns
No full textThe archaeology of rivers to date could be categorized as archaeology in rivers, rather than an archaeology of rivers. Rivers are dynamic entities which form complex entanglements with cultures. However, rivers follow natural processes, and their geomorphology has an elegant underlying structure. These processes lead to cultural patterns that are entangled with the river’s agency, though humans are likewise agents. This chapter examines these processes (e.g. upland/lowland rivers, thalweg, riffle and pool sequences) and the patterns (e.g. settlements, navigation, bridge design) that relate to them. It advocates for an archaeology of rivers which makes use of both terrestrial and submerged information to understand the broader context of riverine cultures
Strategic leadership for sustainable innovation in primary education: a case study of forest school integration
No full textPurpose
This study explores how a primary school in southern England strategically integrated Forest School and smallholding principles into its core educational model. It examines leadership practices, stakeholder engagement, and planning processes underpinning the transformation, offering insights into sustainable innovation in primary education.
Design/methodology/approach
A single-site qualitative case study was conducted. Drawing on strategic management and leadership frameworks—including transformational leadership, Hoshin Planning, the I.AM model, and Ansoff’s Matrix—data were triangulated across strategic documents, stakeholder surveys (n = 112), and semi-structured staff interviews (n = 8). Thematic analysis identified key patterns.
Findings
Integration was facilitated by distributed leadership, strategic value alignment, and stakeholder co-production. Educational outcomes included enhanced pupil engagement, behavioural regulation, and strengthened community partnerships. Challenges such as financial constraints and cultural resistance were addressed through phased planning and responsive leadership.
Research limitations/implications
This is a single-site study in a specific socio-economic context. While not generalisable, findings offer transferable insights for leaders in similar settings.
Practical implications
The study provides guidance for embedding sustainability and innovation via participatory leadership and strategic planning tools. It highlights the value of aligning pedagogy with institutional strategy and stakeholder voice, even in resource-limited environments.
Originality/value
This paper contributes to educational leadership literature by offering a theoretically grounded, practice-led account of school transformation. It shows how structured planning and leadership frameworks support meaningful, sustainable innovation at the primary level.International Journal of Educational Managemen
Fatigue in military aviation
No full textKaya, Gulsum Kubra - Associate SupervisorFatigue in military aviation is gaining momentum as its fast paced and unpredictable
environment is affecting airmen alertness, cognitive performance and impaired
decision-making abilities among many other risks that may trigger or lead to errors and
accidents. This thesis explores fatigue management arrangements in the selected
transportation and logistics unit of one of the European Union Air Forces. Different
methodological approaches were taken to investigate current fatigue and sleep
arrangements among crew members (i.e. pilots and loadmasters) in the selected air
base. The First study in semi-structured interviews gives clearer understanding of the
overall organisational and operational activities, related to fatigue, including within
military culture. The second study is a questionnaire survey which examines the data
gathered and focuses on a construction of a military-specific model encapsulating the
fatigue stressors and countermeasures whilst exploring current management of fatigue
and sleep training. The last study of this thesis uses heuristic evaluation methodology to
develop a military-specific fatigue report form which considers the needs and
complexity of the selected air base. It considers key fatigue-related factors and their
relationships. As a result of this thesis’s research, a Structural Equation Model was
identified to present the correlation of interactions of fatigue, sleep and fatigue
countermeasures and a Fatigue Report Form was developed to enable crew members
in the selected air base to report fatigue. This thesis offers great impact on military
aviation as it is a step towards the development of a Fatigue Risk Management System
which is currently not in place in any European Air Force. Not only does this thesis have
an impact on military aviation, but also in other settings such as, healthcare,
manufacturing, and civilian transportation among many others which could benefit from
the research and results of this thesis.PhD in Transport System
Natural dyes and regenerated cellulose fibers blending using ionic liquid as a common platform for sustainable textiles/fashion applications
No full textConventional textile dyeing generates significant water pollution through synthetic dye leaching, creating urgent need for closed-loop processes. The current work uses a novel in-situ spin dyeing process to develop dyed cellulose fibers, using ionic liquid (IL) as a unified platform to dissolve cellulose and disperse a range of natural dyes – eliminating post-spinning coloration. The spin dyeing method effectively requires less water uptake and is a sustainable benign method for the future textile industry. Different natural dyes were incorporated into the cellulose-IL composite solution to add vibrant colors to the fibers. Natural dyes derived from Sorghum, and Coreopsis show better conjugation with the wet-spun fibers, while the other dyes do not show similar levels of dye stability and incorporation within the fibers. FTIR results confirmed chemical bonding of dyes in the fibers. SEM images indicated the homogeneous dispersion of dye across the fibers. The resultant dyed fibers demonstrate similar mechanical properties in comparison to the neat cellulosic fibers, and commercially available fibers. Although thermal stability decreased for the dyed fibers, mechanical performance validates IL-mediated spin-dyeing as a viable alternative to petroleum-based dyes. This first demonstration of ILs enabling integrated fiber production and natural dyeing establishes a blueprint for sustainable textiles manufacturing.Royal College of Art, EP/V011766/11The work was funded by the Engineering and Physical Sciences Research Council (EP/V011766/11) National Interdisciplinary Circular Economy Research (NICER) programme for the UKRI Interdisciplinary Circular Economy Centre for Textiles: Circular Bioeconomy for Textile Materials. The authors would also like to acknowledge the Textile Circularity Centre (TCC) members from Royal College of Art, London; University of York; and University of Manchester. Abimbola Oluwatayo Orisawayi would also like to acknowledge the Petroleum Technology Development Fund (PTDF) of Nigeria for sponsorship and scholarship support.Carbohydrate Polymer Technologies and Application