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Design of a stacked circularly polarized slot-patch antenna for X-band applications
Get PDFThis paper introduces a numerically investigation of a compact stacked Circularly Polarized (CP) slot-patch antenna designed to operate in X-band (8 -12 GHz). The proposed solution features a coaxially fed circular radiating patch etched on a dielectric substrate, which includes two sector notches positioned on opposite sides at a 45° inclination to achieve circular polarization. Two additional dielectric substrates are placed on the top of the radiating patch, with a parasitic passive patch positioned on each, with the aim of enlarging the overall operating bandwidth. The numerical results demonstrated that the configuration is able to cover a 2.2 GHz band, achieving a minimal Axial Ratio (AR) of 1.2 dB and a gain of 7.4 dB at 10 GHz.2024 IEEE International Symposium on Antennas and Propagation and ITNC-USNC-URSI Radio Science Meetin
Brief communication: lessons learned and experiences gained from building up a global survey on societal resilience to changing droughts
Get PDFThis paper describes the process of creating a global survey of experts to evaluate drought resilience indicators. The lessons learned include five main points: (1) the heterogeneity in the conceptual background should be minimized before the construction of the survey; (2) large numbers of indicators decrease the engagement of respondents through the survey, and ways to apportion indicators whilst maintaining reliability should be considered; (3) it is necessary to design the survey to balance response rate and accuracy; (4) the survey questions should have clear statements with a logical and flowing structure; and (5) reaching experts with different domain experience and representing different regions is difficult but crucial to minimize biased results.Engineering and Physical Sciences Research Council (EPSRC)Natural Hazards and Earth System Science
Advances in the characterisation and identification of mastic (Pistacia sp.) resin in archaeological samples by GC-QToF-MS
No full textThe optimisation and application of an analytical method based on gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QToF-MS) is proposed for the first time for the characterisation and identification of mastic (Pistacia sp.) resin in archaeological samples. The GC-QToF-MS method demonstrated higher sensitivity compared to single quadrupole GC-MS and enabled enhanced structural elucidation power to be exploited, particularly due to the high mass resolution and accuracy, the possibility to use standard and low ionisation energies as well as its tandem MS capabilities. The heat-induced degradation of the resin was also studied in open air conditions, showing that 28-norolean-17-en-3-one forms upon heating, but then progressively degrades. This makes it a reliable marker for heating of Pistacia resin; however, the lack of detection does not imply that the resin was not heated. These observations were used to interpret the results of a large number of archaeological samples containing Pistacia resin in different formulations, from various archaeological contexts and exposed to different environmental conditions. Lumps of relatively pure resin found in marine waterlogged conditions (Uluburun shipwreck, Turkey), residues on ceramics from Sai Island (Nubia, Sudan) as well as varnish and coating layers on Egyptian coffins from the collections of the British Museum (London, UK) and Fitzwilliam Museum (Cambridge, UK) were analysed to understand what the molecular profiles reveal about the use of the resin. The results showed that the resin was often mixed with a drying or semi-drying oil in ancient varnish formulations, thus suggesting that oil was used as a medium to dissolve the resin, which would have been impossible to apply as a layer using simple heat. These new observations significantly add to our understanding of ancient Egyptian technology and provide museum scientists and conservators with key information to accurately identify Pistacia resin and preserve objects containing it.Arts and Humanities Research Council (AHRC)We are grateful to the Wellcome Trust for Grant 097365/Z/11/Z, which funded salaries of Kate Fulcher and Rebecca Stacey, and to the Arts and Humanities Research Council (AHRC) for supporting Nelly von Aderkas to participate in the study with funding from the additional student development fund (ASDF). The AHRC are also thanked for CapCo grant AH/V011766/1, which funded the purchase of the GC-QTOF instrument used in this work. This article is made Open Access through the support of a UKRI Open Access Block Grant.RSC advance
A complementary fusion-based multimodal non-destructive testing and evaluation using phased-array ultrasonic and pulsed thermography on a composite structure
Get PDFCombinative methodologies have the potential to address the drawbacks of unimodal non-destructive testing and evaluation (NDT & E) when inspecting multilayer structures. The aim of this study is to investigate the integration of information gathered via phased-array ultrasonic testing (PAUT) and pulsed thermography (PT), addressing the challenges posed by surface-level anomalies in PAUT and the limited deep penetration in PT. A center-of-mass-based registration method was proposed to align shapeless inspection results in consecutive insertions. Subsequently, the aligned inspection images were merged using complementary techniques, including maximum, weighted-averaging, depth-driven combination (DDC), and wavelet decomposition. The results indicated that although individual inspections may have lower mean absolute error (MAE) ratings than fused images, the use of complementary fusion improved defect identification in the total number of detections across numerous layers of the structure. Detection errors are analyzed, and a tendency to overestimate defect sizes is revealed with individual inspection methods. This study concludes that complementary fusion provides a more comprehensive understanding of overall defect detection throughout the thickness, highlighting the importance of leveraging multiple modalities for improved inspection outcomes in structural analysis.Material
AgriFoodPy: a package for modelling food systems
Get PDFAgriFoodPy is an open-source Python package for processing, simulation, and modeling of agrifood datasets and systems. By employing xarray (Hoyer & Hamman, 2017) as the primary data structure, AgriFoodPy provides methods to manipulate tabular data by extending xarray functionality via accessor classes. It acts as an accessibility and interoperability layer between data sources and external packages, and also bundles with a library of models for use without any additional requirements.
A separate repository, agrifoodpy_data, is actively maintained in parallel to provide access to local and global agrifood datasets, including geospatial land use and classification data (Morton, 2022), food supply (FAO, 2023), life cycle assessment (Poore & Nemecek, 2018), and population data (United Nations, 2022). The AgriFoodPy framework is region-agnostic and provides facilities to model and simulate processes and intervention impacts regardless of their geographic origin.UKRI Transforming Food Systems Strategic Priority Fund (grant number BB/V004581/1)Journal of Open Source Softwar
Strategic implementation of ED&I: unveiling the multifaceted impact on innovation, governance, and ethical conduct in engineering organizations
Get PDFIn contemporary organizational landscapes, Equity, Diversity, and Inclusion (ED&I) stand as pivotal pillars for fostering innovation, resilience, and sustainable growth. This article explores the critical importance of ED&I within engineering organizations, focusing on the strategies for understanding ED&I dynamics, implementing inclusive environments, and extending ED&I principles through the industrial value chain. It investigates the complexities of individual identities, the significance of intersectionality, and the strategic advantage of diversity for organizational performance. By exploring comprehensive governance of ED&I initiatives, the role of leadership in fostering diversity, and the impact of ED&I on organizational sustainability and innovation, this study provides a holistic view of the challenges and opportunities in creating inclusive workplaces.Frontiers in Industrial Engineerin
Achieving net zero neighborhoods: a case study review of circular economy initiatives for South Wales
Get PDFAdopting net zero neighborhoods (NZN) combined with circular economy are increasingly recognized as an essential strategy for construction companies, allowing their transition towards sustainability and contributing to climate change mitigation. Transforming existing neighborhoods into NZN is necessary to achieve energy self-sufficiency and net zero by 2050. The success of NZN hinges on government initiatives. However, existing studies appear to lack a comprehensive exploration of the transformation initiatives within NZN, spanning aspects like raw materials, construction practices, transportation, and waste management, particularly in terms of technological advancements. To address the gap, this research introduces a conceptual framework that integrates the multiple case studies design method with an urban transformative capacity model. This innovative framework is the first application of a multi-level urban transformative capacity model in transforming existing neighborhoods into NZN within a specific region. This research specifically utilizes South Wales in the UK as a case study. It identified four key initiatives in technology, construction, transportation, and waste management. These initiatives offer significant benefits, including fostering a more sustainable and environmentally friendly construction industry through enhanced traceability and efficiency, and simultaneously promoting social sustainability by improving community engagement, providing social benefits through sharing economy initiatives, and creating new green job opportunities.Engineering and Physical Sciences Research Council (EPSRC)Journal of Cleaner Productio
Ammonia recovery and utilisation for biogas upgrading in membrane contactors.
Get PDFPidou, Marc - Associate SupervisorThis thesis has developed an innovative system for biogas upgrading using
hollow fibre membrane contactors (HFMC) whilst recovering ammonia from
wastewater as a reactive solvent to intensify CO₂ absorption. An expanded two-
phase region for ammonia-water separation was identified and exploited to foster
selective, low energy recovery of concentrated gas-phase ammonia from
wastewater by vacuum thermal stripping. Selective stripping was translated to a
gas-liquid contacting column which demonstrated mass transfer rates analogous
to commercially established stripping processes. Investment in selective
ammonia recovery from anaerobic digester centrate represents a cost saving
over a 20-year economic lifetime relative to biological nitrogen removal. During
physical CO₂ absorption in HFMC, solvent chilling and gas pressurisation were
observed to increase flux and selectivity, thereby reducing membrane area and
path length for biogas upgrading. Chilled conditions will promote wetting
resilience to favour the application of microporous membranes, which are low-
cost and technologically mature. Translation to recovered ammonia solvents will
further intensify CO₂ absorption, but can result in gas-side reactions within the
ternary CO₂-NH₃-H₂O system which reduce process stability. In a positive
synergy, chilled, pressurised conditions could limit ammonia ‘slip’ and maintain
the system below a critical threshold to prevent gas-side reactions and improve
process resilience. Pressurised, reactive crystallisation in HFMC during CO₂
absorption by ammonia solvents was demonstrated for the first time, and
observed to occur at a consistent supersaturation level. Consequently,
ammonium bicarbonate crystals exhibited consistent characteristics independent
of pressure which supports simplified online control and solids recovery for scale-
up. The integrated system proposed in this thesis presents a cost effective,
circular economy solution for ammonia recovery and biogas upgrading which is
closely aligned to net zero ambitions within the water sector and wider society.STREAM EngD Programm
A novel physics-informed recurrent neural network approach for state estimation of autonomous platforms
Get PDFState estimation of autonomous platforms is a crucial element in the design and test of perception algorithms. The nonlinear nature of autonomous platforms makes hard to design accurate state estimation algorithms without using linearization techniques, large amount of data or knowledge of the physical parameters of the platform. This paper reports a novel state estimation algorithm of autonomous platforms. The proposed approach is based on a physics informed recurrent neural network (PIRNN) that combines the power of recurrent nets with an estimate structure of the autonomous platform model. This estimated model regularises the weights’ manifold of the network for the accurate estimation of the states. Boundedness of the proposed PIRNN is verified using Lyapunov stability theory as long as the physics-informed signals satisfy a persistent of excitation condition. Simulations are conducted to test the PIRNN model and show its benefits and challenges.Engineering and Physical Sciences Research Council (EPSRC)This work was supported by the Engineering and Physical Sciences Research Council under Grant EP/V026763/1.2024 International Joint Conference on Neural Networks (IJCNN
Heat load development and heat map sensitivity analysis for civil aero-engines
Get PDFThe design complexity of the new generation of civil aero-engines results in higher demands on engines’ components, higher component temperatures, higher heat generation, and, finally, critical thermal management issues. This paper will propose a methodological approach to creating physics-based models for heat loads developed by sources, as well as a systematic sensitivity analysis to identify the effects of design parameters on the thermal behavior of civil aero-engines. The ranges and levels of heat loads generated by heat sources (e.g., accessory gearbox, bearing, pumps, etc.) and the heat absorption capacity of heat sinks (e.g., engine fuel, oil, and air) are discussed systematically. The practical research challenges for thermal management system design and development for the new and next generation of turbofan engines will then be addressed through a sensitivity analysis of the heat load values as well as the heat sink flow rates. The potential solutions for thermal performance enhancements of propulsion systems will be proposed and discussed accordingly.International Journal of Turbomachinery, Propulsion and Powe