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Assessing the reliability of open-source data used for spatial characterisation of urban sanitation infrastructure—a field study in Rajshahi, Bangladesh
Get PDFUrban sanitation in rapidly growing secondary cities remains a critical challenge, particularly in unsewered areas. This study evaluates the effectiveness of open-source data for modelling the sources and movement of faecal matter in such contexts, with a specific focus on Rajshahi, an unsewered secondary city in Bangladesh. By triangulating data from direct observations, key informant interviews (KIIs), and focus group discussions (FGDs), we assess the reliability of using open-source data to map faecal matter flow. The findings demonstrate an 80% alignment between the model’s simulated flow directions and actual field observations, highlighting the potential of using open-source data in urban sanitation management. Furthermore, the study reveals that 80% of buildings are connected to storm drains with many allowing faecal matter to overflow from septic tanks, thus posing a health risk. Despite efforts by the City Corporation to manage the drainage system through reactive measures like drain scraping and unblocking, blocked and overflowing drains remain prevalent, particularly during the rainy season. KIIs and (FGDs) highlight a lack of proactive maintenance and widespread unawareness of sanitation management systems. This integration of field-based insights with open-source data supports for a more proactive, data-driven approach to urban sanitation management in secondary cities, ultimately aiming to enhance public health and quality of life.Engineering and Physical Sciences Research Council (EPSRC)This research was funded by the UKRI Engineering and Physical Science Research Council (EPSRC), under the auspices of the EPSRC Centre for Doctoral Training in Water and Waste Infrastructure and Services Engineered for Resilience (Water-WISER), providing a doctoral scholarship to the principal author (M.S. S.) [EPSRC Grant No. EP/S022066/1].Environmental Science and Pollution Researc
Chemical process design of solid waste management for use in railway rolling stock
Get PDFWilliams, Leon - Associate SupervisorProper management and disposal of highly wet hazardous sanitary solid wastes
is of utmost importance for developing countries or parts of developed ones
where sewage infrastructure is inaccessible. For instance, the sewage generated
in on-board train toilets is being stored in a controlled emission tank (CET) fitted
under the carriages that is further emptied in depot using extraction facilities. A
method still requiring the final management of generated sludge while being
costly with the train being pulled off the track.
Implementation of advanced thermal processes in small scales within the context
of a decentralized wastewater treatment system has recently been found
promising for the on-site stabilisation of sanitary faecal sludge. This research has
outlined the requirements, challenges and constraints associated with the
utilisation of thermal conversion technologies to aid in the development of system
for this application. The thermochemical properties of multiple batches of solid
wastes stored in CETs has been characterized for the first time to aid in the
design of an innovative pyrolysis system. A drying unit for the simultaneous pre-
treatment and resource recovery from faecal sludge is developed. The drying
efficiency of the unit is evaluated, and the extent of nutrients recovered through
the unit are discussed while design implications for further improvements are
provided. Following this, the obtained data on the chemical properties of partially
dried products are used for the testing and evaluation of a pyrolysis reactor.
The prototype was a novel twin auger pyrolysis reactor based on the application
constraints and successfully commissioned. Effects of various process
parameters on the conversion of faecal sludge is assessed through extensive
chemical characterization of the process products (e.g., syngas, biooil and
biochar). The outcomes of the research were discussed to provide insight into the
by-products for further disposal or usage.
Throughout this thesis, points for further research are highlighted based on the
findings and observations.PhD in Energy and Powe
Stress analysis of gun breech block for gun design applications
Get PDFThis study presents a detailed Finite Element Analysis (FEA) of a breech block featuring a buttress thread, aimed at understanding the stress distribution under various loading conditions. Buttress threads, known for their high load-bearing capacity and asymmetrical profile, are commonly used in applications where high axial loads are required, such as in hydraulic systems and fasteners. Utilizing Abaqus, a comprehensive stress analysis was conducted on the threaded block to assess critical factors such as stress concentration, deformation patterns, and the overall integrity of the design under different loading scenarios. The model was created using precise geometric definitions of the buttress thread, including the lead angle and asymmetric thread profiles. The material properties were assigned based on realistic parameters commonly used in industrial applications, this material was steel 4340. Static loading conditions were applied to simulate operational stresses, and a fine mesh was employed to capture the detailed stress distribution around the thread roots and flanks, where stress concentrations are typically highest. The results revealed that the buttress thread design effectively distributes axial loads along the inclined surface, minimizing stress concentrations compared to conventional thread forms. This design of the breech block based on the buttress thread is extremely important when it comes to the gun design and it is a good reason why the buttress thread is design in this way for most guns. However, significant stress concentration was observed at the root of the thread, necessitating potential design optimizations. This analysis demonstrates the efficacy of buttress threads for highload applications in gun designs, with the FEA results providing valuable insights for further refinement of the design. The study validates the use of Abaqus in performing detailed stress analysis of complex geometries, showcasing its capability to predict critical stress regions and potential failure points. Recommendations for future work include fatigue analysis and exploring the effects of varying thread dimensions on stress distribution to judge the novelty in our work.34th International Symposium on Ballistic
Does cutting airport slots reduce climate impact? the case of Amsterdam airport
Get PDFThis study evaluates the effectiveness of airport slot reductions as a strategy for mitigating greenhouse gas (GHG) emissions, focusing on Amsterdam Schiphol Airport. Following the Dutch Government's decision to reduce slots from 500,000 to 440,000, we analyse various risk scenarios using the D'Hondt method for proportional slot allocation and the Fuel Estimation in Air Transportation (FEAT) model to estimate fuel consumption. Strategies include proportional slot cuts, prioritising short-haul flights, and shifting to rail alternatives. Results show that short-term emissions reductions are modest and do not scale with slot reductions unless long-haul flights are significantly curtailed. Moreover, aircraft up-gauging could lead to increased emissions if airline behaviour is not addressed. Our findings challenge the effectiveness of slot reductions as a climate strategy, highlighting the importance of targeting long-haul flights and adopting comprehensive policies to achieve substantial emissions reductions. The study offers critical insights for sustainable aviation policy development.Transportation Research Part D: Transport and Environmen
Engineering biology applications for environmental solutions: potential and challenges
Get PDFEngineering biology applies synthetic biology to address global environmental challenges like bioremediation, biosequestration, pollutant monitoring, and resource recovery. This perspective outlines innovations in engineering biology, its integration with other technologies (e.g., nanotechnology, IoT, AI), and commercial ventures leveraging these advancements. We also discuss commercialisation and scaling challenges, biosafety and biosecurity considerations including biocontainment strategies, social and political dimensions, and governance issues that must be addressed for successful real-world implementation. Finally, we highlight future perspectives and propose strategies to overcome existing hurdles, aiming to accelerate the adoption of engineering biology for environmental solutions.All authors acknowledge support from the UK Research and Innovation (UKRI) Biological Sciences Research Council (BBSRC) grant BB/Y008332/1. F.C. and T.G. acknowledges support from UKRI BBSRC grant BB/S009795/1. ZY thanks The Leverhulme Trust Research Leadership Awards RL-2022-041.Nature Communication
Designing nickel coatings for water erosion performance: optimisation of grain size and thickness
Get PDFMetallic coatings are gaining interest as an alternative to classical polymeric layers for erosion damage prevention due to their extended durability and sustainability. However, their implementation requires a thorough understanding of protective potential and reliability. This study explores the use of brush-plated nickel coatings on carbon-fibre reinforced composites to enhance their performance against water erosion. A combination of experimental analysis and computational modeling explores the effect of different coating thickness and properties to withstand water droplet erosion damage. Findings reveal a minimum critical coating thickness around 40 μ m can significantly improve the erosion resistance.We wish to acknowledge the support of the Henry Royce Institute for advanced materials through the Materials Challenge Accelerator Programme, funded from a grant provided by the Engineering and Physical Sciences Research Council, United Kingdom (EP/X527257/1).Engineering Failure Analysi
Comments on ‘First signs that national cropland organic carbon loss is reversing in British topsoils’ by Bentley et al.
Get PDFIn an analysis of the most recent data from the UKCEH Countryside Survey, Bentley et al. (2025) find a modest increase in soil organic carbon (SOC) stocks of topsoil in croplands across Great Britain from 2007 to 2020, and they suggest this is the first evidence of a reversal of soil carbon loss at national scale anywhere, linked to improvements in land management. This is a significant claim, and the paper is likely to be highly cited. However, some important caveats are apparent from a close reading of the paper, and the results need to be treated with caution. The authors do say this but in drawing conclusions they appear to overlook this caution and the necessary caveats.European Journal of Soil Scienc
Evaluation and adaptation of portable x-ray fluorescence and data fusion techniques for non-invasive characterisation of metal-contaminated environments
No full textCampo Moreno, Pablo - Associate Supervisor
Wagland, Stuart T. - Associate SupervisorMetal extraction and refinement has left a legacy of brownfield and post
metallurgical sites, which present risks to health and the environment. However,
these sites present an opportunity to provide the critical resources needed to
meet the global energy transition to net zero. A key barrier to the resource
recovery and remediation of these sites is the expensive and slow surveying
methods currently in use. Addressing this barrier, this PhD aimed to develop an
innovative rapid, non-invasive method for quantifying elemental and speciated
metals in contaminated soils using portable X-ray fluorescence (pXRF) and
visible-near infrared (Vis-NIR) spectroscopy. Research investigated the
applicability of these methods and evaluated the influence of sample preparation
and inter-sample interferences through four objectives.
Firstly, when investigating the effects of sample pre-processing on ex-situ pXRF
measurements of samples collected from a post-metallurgical site; it was
identified that sieving and grinding improved pXRF precision (average relative
standard deviation fell by 7.17% and 8.37% respectively); while drying and
grinding enhanced pXRF accuracy (average r2 increased by 0.03 and 0.10
respectively).
Secondly, the correlation of pXRF and geophysical measurements was
investigated for the first time ever at a heterogeneous post-metallurgical site. No
correlations (r² < 0.46) were observed between the two approaches, which was
attributed to the differing sample volumes and depths measured by these
methods. It was concluded that matrix heterogeneity and the scale disparity
between geophysical and chemical sampling present significant challenges to
rapid methodologies.
Thirdly, to overcome the interference caused by moisture and soil organic matter
(SOM) on in-situ pXRF measurements, a novel data fusion framework using
pXRF and Vis-NIR was developed. During its development, it was identified, for
the first time, that moisture had an elementally dependent non-linear trend with
substantial underpredictions by pXRF at ~15% moisture. Furthermore, this
research also showed, for the first time, that SOM caused an insubstantial but
significant difference in performance of pXRF predictions. However, the data
fusion framework successfully accounted for both moisture and SOM in all
elements measured, with Ca showing the largest improvement (r² = 0.308).
And fourth, to predict to determine the feasibility of predicting metal speciation, a
simplified, artificial sample matrix containing multiple iron compounds was again
measured with both pXRF and Vis-NIR. This novel approach demonstrated for
the first time that speciated Fe concentration can be accurately predicted (r² =
0.96) in a heterogeneous solid sample.
This PhD thesis proposes a best-practice methodology for ex-situ pXRF analysis,
addressing the effects of sample preprocessing. The methodology can be
immediately implemented to reduce financial cost of collecting data in
contaminated land surveys. Additionally, through further development of the data
fusion framework for in-situ measurements, significant time and cost savings can
be achieved, allowing for increased data collection and the generation of
qualitative models in the early stages of contaminated land assessments.
Furthermore, this research demonstrates the potential to predict metal speciation,
with the possibility of reducing the cost of speciation data acquisition. Such
advancements would enable more targeted remediation and resource recovery
efforts at contaminated sites.PhD in Wate
Deep learning-driven x-ray digital tomosynthesis (DT) imaging for aerospace composite inspection
No full textThe structural integrity of aerospace-grade Glass Fiber Reinforced Polymer (GFRP) composites is critical, yet conventional non-destructive testing (NDT) methods often struggle to detect subsurface defects reliably due to poor signal-to-noise ratios, low contrast, and complex internal structures. To address these limitations, this study proposes a novel AI-driven framework that integrates low-power X-ray Digital Tomosynthesis (DT) imaging with state-of-the-art deep learning models for defect segmentation in composite materials. Specifically, two state-of-the-art instance segmentation models, YOLOv8 (You Only Look Once, version 8) and Detectron2, are employed to automatically segment flaws in the DT images of the composite specimens. A dedicated dataset of low-power X-ray DT scans of GFRP composite specimens with annotated defects was curated for training and evaluation. The segmentation performance of each model was quantitatively evaluated using metrics such as the Dice similarity coefficient and Intersection-over-Union (IoU), along with inference time measurements. Experimental results demonstrate that YOLOv8 processes images significantly faster (~6.9 ms per image) than Detectron2 (~10.3 ms), enabling near real-time analysis. Conversely, Detectron2 achieves a higher segmentation accuracy (Dice ~86% versus ~74% for YOLOv8), underscoring the trade-off between computational efficiency and segmentation precision. These findings validate the potential of combining low-power DT imaging with deep learning for high-fidelity defect identification, substantially improving the prospects for near real-time composite inspection. Future work will focus on further model optimization (e.g., via quantization and pruning) and the integration of this framework with autonomous robotic inspection systems, thereby extending the capabilities of AI-driven NDT in aerospace applications.Aerospace Technology InstituteThis work was supported by ATI funding for advanced manufacturing inno-vation - ATI ROBOT-MOUNTED 3D X-RAY INSPECTION.Towards Autonomous Robotic Systems 26th Annual Conference, TAROS 202
Integrated design and operation assessment of a preheating system for liquid hydrogen fuelled engines
Get PDFCryogenic liquid hydrogen (LH2) is highly considered as a potential long-term solution towards emissions reduction in the aviation sector. However, one of the major challenges that the handling and integration of the cryogenic fuel introduces is its thermal management. In this paper, the design space exploration of an LH2 conditioning is presented to identify potential feasible solutions and limitations for its implementation. The preheating system comprises of secondary combustor that feeds a heat exchanger with hot gasses to adequately supply the main engine with gaseous hydrogen at a constant temperature. The design space exploration addresses the heat exchanger design as well as the effect of retrofitting the system on kerosene-designed engines with different specific thrust.
For performing the analysis, four baseline engine models and their equivalent integrated versions with the fuel preheating system have been created. Additionally, a framework for the sizing and off-design performance characterisation of the heat exchanger is introduced. The integrated system performance across the design space is analysed and a novel control strategy of the preheating system is proposed with the view of avoiding water vapour condensation of the hot gasses of the preheating module. By applying this control, it was found that heat exchanger designs with lower effectiveness are less likely to lead to water condensation conditions and can adequately be supported with air sourced from the by-pass duct without significant penalty in the overall energy efficiency of the engine.The authors are grateful to Rolls-Royce plc for its guidance during the project and Empresarios Agrupados for their continuous support with PROOSIS. This research has received funding from Innovate UK under project reference 10039770 (LH2GT).ASME Turbo Expo 2025: Turbomachinery Technical Conference and Expositio