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An ever-winding stream : (re)surfacing competing for advantage from the continuous entwinement of navigation and wayfinding
Get PDFThis research is a strategy coup de grâce. It has helped mend deeply-rooted, intuitive, in situ sponte sua beliefs about the nature of strategy’s river-flow—echoed from a minuscule, scarcely-inhabited river-cave of the strategy field-flow—with its actual unfolding in real, earth-bound organisational settings. In a nutshell, the research charted the until-now uncharted becoming of competing for advantage.For what Sheryl Crow sings in her immensely popular ‘Everyday is a winding road’ is simply the sentiment Bob Dylan so effectively describes ‘Like a rolling stone’ in a way that completely resonates with what the Beatles had sung even before in their ‘Long and winding road’. Namely, that strategy is wayfaring, meandering, and forever oblique. And hence, strategy is not either linear or curve, but both linear and curve. Deliberate and emergent. Content and process. Planning and wayfinding, in a universal, uninterrupted coping, which echoes ‘the best-laid plans of mice and men’ (Burns, 1785, added emphasis) so beautifully captured in the evocative poetics of Scotland’s national bard.Over a 9-month immersion during most of 2018, in an automotive manufacturing site in the outskirts of Glasgow’s Green-Glen, the research amassed a comprehensive volume of data anchorings following a ‘near documentary’ style of inquiry (Chia and Holt, 2009). A wayfinding methodology-of-sorts emerged, which included extensive field note-makings, reflecting-in-action, photographic animations, and annotated information supported by news articles, company records, semi-formal interviews, live off-the-cuff conversations, shadowing-in-observation, and attendance of both formal, fixed meetings, and informal, impromptu coming-together gatherings. Analysis followed to reconstruct the river-flow of the case-streams. Namely, the metamorphosis of Rosti Automotive Larkhall (RAL), from being a general plastic injection moulder, to becoming a tier 1 automotive supplier, in the period covering 2016-2018.Overarchingly, the research crystalizes a triple-win of exciting possibilities for the field of strategic management and the social sciences more broadly. Namely, (i) a tried-and-tested wayfinding-process philosophical-methodology focused on explicating the dynamics of processes-in-motion; (ii) a fresh reconceptualization of a central construct—the central construct, perhaps—of the strategy field, competitive advantage, towards a forever becoming-idea—the primordial hunch of strategy—competing for advantage; and (iii) this new conceptualisation is born out of the two most basic motions—currents—of the competing river-flow: competere and concurrere, from which concurrere emerges as the vital traversing of strategy, its wayfinding and zero-degree of organisation (Chia and Holt, 2009; Cooper 1986: 321).This research is a strategy coup de grâce. It has helped mend deeply-rooted, intuitive, in situ sponte sua beliefs about the nature of strategy’s river-flow—echoed from a minuscule, scarcely-inhabited river-cave of the strategy field-flow—with its actual unfolding in real, earth-bound organisational settings. In a nutshell, the research charted the until-now uncharted becoming of competing for advantage.For what Sheryl Crow sings in her immensely popular ‘Everyday is a winding road’ is simply the sentiment Bob Dylan so effectively describes ‘Like a rolling stone’ in a way that completely resonates with what the Beatles had sung even before in their ‘Long and winding road’. Namely, that strategy is wayfaring, meandering, and forever oblique. And hence, strategy is not either linear or curve, but both linear and curve. Deliberate and emergent. Content and process. Planning and wayfinding, in a universal, uninterrupted coping, which echoes ‘the best-laid plans of mice and men’ (Burns, 1785, added emphasis) so beautifully captured in the evocative poetics of Scotland’s national bard.Over a 9-month immersion during most of 2018, in an automotive manufacturing site in the outskirts of Glasgow’s Green-Glen, the research amassed a comprehensive volume of data anchorings following a ‘near documentary’ style of inquiry (Chia and Holt, 2009). A wayfinding methodology-of-sorts emerged, which included extensive field note-makings, reflecting-in-action, photographic animations, and annotated information supported by news articles, company records, semi-formal interviews, live off-the-cuff conversations, shadowing-in-observation, and attendance of both formal, fixed meetings, and informal, impromptu coming-together gatherings. Analysis followed to reconstruct the river-flow of the case-streams. Namely, the metamorphosis of Rosti Automotive Larkhall (RAL), from being a general plastic injection moulder, to becoming a tier 1 automotive supplier, in the period covering 2016-2018.Overarchingly, the research crystalizes a triple-win of exciting possibilities for the field of strategic management and the social sciences more broadly. Namely, (i) a tried-and-tested wayfinding-process philosophical-methodology focused on explicating the dynamics of processes-in-motion; (ii) a fresh reconceptualization of a central construct—the central construct, perhaps—of the strategy field, competitive advantage, towards a forever becoming-idea—the primordial hunch of strategy—competing for advantage; and (iii) this new conceptualisation is born out of the two most basic motions—currents—of the competing river-flow: competere and concurrere, from which concurrere emerges as the vital traversing of strategy, its wayfinding and zero-degree of organisation (Chia and Holt, 2009; Cooper 1986: 321)
The WTO dispute settlement system : one size does not fit all
Get PDFThis thesis examines the operation of the World Trade Organisation (WTO) Dispute Settlement Understanding (DSU) from the perspective of the Least Developed Countries (LDCs). Ensuring predictability and stability in the rules-based international trading system requires the DSU to be accessible, efficient, reliable, and able to redress imbalances. The inability of the LDCs to fully utilise with the DSU, thus denigrates their ability to redress imbalances and, by extension, their ability to fully engage in international trade, which logically could restrict their economic growth. This thesis builds upon our existing knowledge by exploring and examining why the LDCs, having brought only one dispute, appear to have difficulties -engaging with the DSU, and this thesis reveals a series of issues and concerns. Since the 1990s, the DSU has been the subject of review, and this thesis also explores these ongoing review negotiations from an LDC viewpoint.This LDC-focused analysis and evaluation represent an original and important contribution to the general body of academic knowledge, illuminating areas of these negotiations which have hitherto been overlooked within the academic fora. The thesis also narrates how during both the negotiations which led to the creation of the DSU and those relating to its review, the repeated failure of the LDC proposals to either gain traction or even, upon occasion, be discussed by the wider WTO membership, contributed towards a growing bias amongst the LDCs against engaging with the DSU which is a recurring theme of this thesis. The thesis makes recommendations to address some of the engagement issues faced by the LDCs. Arguing that WTO action alone will not address all these issues, the thesis advocates that the LDCs must themselves be prepared to take measures to address their structural and other weaknesses.This thesis examines the operation of the World Trade Organisation (WTO) Dispute Settlement Understanding (DSU) from the perspective of the Least Developed Countries (LDCs). Ensuring predictability and stability in the rules-based international trading system requires the DSU to be accessible, efficient, reliable, and able to redress imbalances. The inability of the LDCs to fully utilise with the DSU, thus denigrates their ability to redress imbalances and, by extension, their ability to fully engage in international trade, which logically could restrict their economic growth. This thesis builds upon our existing knowledge by exploring and examining why the LDCs, having brought only one dispute, appear to have difficulties -engaging with the DSU, and this thesis reveals a series of issues and concerns. Since the 1990s, the DSU has been the subject of review, and this thesis also explores these ongoing review negotiations from an LDC viewpoint.This LDC-focused analysis and evaluation represent an original and important contribution to the general body of academic knowledge, illuminating areas of these negotiations which have hitherto been overlooked within the academic fora. The thesis also narrates how during both the negotiations which led to the creation of the DSU and those relating to its review, the repeated failure of the LDC proposals to either gain traction or even, upon occasion, be discussed by the wider WTO membership, contributed towards a growing bias amongst the LDCs against engaging with the DSU which is a recurring theme of this thesis. The thesis makes recommendations to address some of the engagement issues faced by the LDCs. Arguing that WTO action alone will not address all these issues, the thesis advocates that the LDCs must themselves be prepared to take measures to address their structural and other weaknesses
Comparative genomics to understand specialised metabolism in Micromonospora
Get PDFHyphal, sporulating members of the Actinomycetota (actinomycetes) – genera suchas Micromonospora and Streptomyces – are notable for production of multiple usefulantibiotic natural products. The aim of this project was to screen actinomycete isolatesfrom the Atacama Desert and Scottish soil for production of natural product antibioticswhich inhibit the growth of Pseudomonas aeruginosa, a frequently multidrug resistantpathogen, and to sequence the genomes of producing organisms to identifybiosynthetic gene clusters (BGCs) which drove that activity.Here we report the sequence of four actinomycetes – one Streptomyces isolate fromGlasgow Botanic Gardens (S. sp. GBG 9AT) and three Micromonospora(Micromonospora sp. O3, Micromonospora sp. O5, and Micromonospora sp. PH63)isolated from Atacama Desert Soil. Multiple Sequence Alignment based phylogenyand average nucleotide identity (ANI) calculations identified S. sp. GBG 9AT asStreptomyces xanthophaeus, a well characterized streptomycete. The samemethodology identified the three Micromonospora isolates as three novelgenospecies. All organisms were BGC rich.We also sought out to examine possible regulation of these BGCs. Of well-knowndevelopmental regulators conserved within Streptomyces, we identify the masterregulator BldD as the only universally conserved regulator within the threeMicromonospora. In addition, the three strains are predicted to lack functional BldA,a developmentally regulated tRNA which controls morphological differentiation andantibiotic production. Finally, we analysed the loci of BGCs in single contig assembliesof Micromonospora and identify two distinct populations of BGCs occupying the oriCproximal and oriC-distal regions of the chromosome, a distribution distinct from thatof Streptomyces.This work shows a genomic landscape in Micromonospora which is distinct from thatof previously studied actinomycetes and lays the groundwork for future studies of theevolution of antibiotic production in these organisms.Hyphal, sporulating members of the Actinomycetota (actinomycetes) – genera suchas Micromonospora and Streptomyces – are notable for production of multiple usefulantibiotic natural products. The aim of this project was to screen actinomycete isolatesfrom the Atacama Desert and Scottish soil for production of natural product antibioticswhich inhibit the growth of Pseudomonas aeruginosa, a frequently multidrug resistantpathogen, and to sequence the genomes of producing organisms to identifybiosynthetic gene clusters (BGCs) which drove that activity.Here we report the sequence of four actinomycetes – one Streptomyces isolate fromGlasgow Botanic Gardens (S. sp. GBG 9AT) and three Micromonospora(Micromonospora sp. O3, Micromonospora sp. O5, and Micromonospora sp. PH63)isolated from Atacama Desert Soil. Multiple Sequence Alignment based phylogenyand average nucleotide identity (ANI) calculations identified S. sp. GBG 9AT asStreptomyces xanthophaeus, a well characterized streptomycete. The samemethodology identified the three Micromonospora isolates as three novelgenospecies. All organisms were BGC rich.We also sought out to examine possible regulation of these BGCs. Of well-knowndevelopmental regulators conserved within Streptomyces, we identify the masterregulator BldD as the only universally conserved regulator within the threeMicromonospora. In addition, the three strains are predicted to lack functional BldA,a developmentally regulated tRNA which controls morphological differentiation andantibiotic production. Finally, we analysed the loci of BGCs in single contig assembliesof Micromonospora and identify two distinct populations of BGCs occupying the oriCproximal and oriC-distal regions of the chromosome, a distribution distinct from thatof Streptomyces.This work shows a genomic landscape in Micromonospora which is distinct from thatof previously studied actinomycetes and lays the groundwork for future studies of theevolution of antibiotic production in these organisms
A novel antibody to target Multiple Myeloma : a combined modelling and experimental study
No full textNeural networks applied to ocean colour remote sensing for environmental monitoring
Get PDFAutotrophic algal organisms that perform photosynthesis are the basis of the marine food web and absorb up to 30% of the anthropogenic emitted CO2 (Gruber et al., 2007). The algal concentration can be measured by retrieving their chlorophyll a concentration from remote sensing. The light signal measured from satellites needs to be corrected for various atmospheric and water surface effects. After atmospheric correction, the water leaving signal can be isolated and different algorithms exist to retrieve chlorophyll a. In open waters, blue-green ratios perform well (O’Reilly et al., 1998). In coastal waters, other water constituents (dissolved matter and sediments) make both the atmospheric correction process and the chlorophyll a estimates harder as they alter the light signal. Current chlorophyll algorithms therefore tend to perform poorly for turbid coastal waters. To develop a better algorithm, a northwest European shelf seas matchup dataset is built by collecting in situ chlorophyll a and MODIS Aqua sensor data. Different neural network algorithms are developed to make the best possible estimates of chlorophyll a, using either the bottom of atmosphere reflectance Rrs, commonly used by other algorithms, or top of atmosphere reflectances, when no atmospheric correction was applied to the light signal.It is found that the uncorrected top of atmosphere signal produces better and more reliable estimates over the entire dataset which contains mainly nearshore samples. Small neural network architectures containing 3 hidden layers of 15 neurons show good performances. The randomness involved in what a single neural network produces is tackled by using an ensemble approach of ten networks. The use of the whole light spectrum from 412 nm to 2130 nm produced the best estimates and should lead future dataset creations that currently do not include all available spectral information. The neural network algorithm developed here for chlorophyll a works well for turbid coastal waters where other algorithms either fail or mask out the data after applying quality control flags. The greatest impact is likely to be for nearshore waters where turbidity tends to be greatest. The approach developed here for NW European shelf seas has potential to be extended to global scale operation if a suitable training data set can be collected in future. The process is repeated for a modelled dataset and shows almost perfect estimates of the three different water constituents that alter the light signal. Temperature can also be estimated with better performance using the same approach which allows creation of a single temperature algorithm that works during both day and night, for any month and position on Earth. The benefit of using an enhanced chlorophyll a algorithm is later evaluated from the eutrophication assessment point of view. Remote sensing techniques produce several orders of magnitude more data than the current in situ approach to assess the eutrophication status and should help policymakers in producing coherent and improved assessment of the environment.Autotrophic algal organisms that perform photosynthesis are the basis of the marine food web and absorb up to 30% of the anthropogenic emitted CO2 (Gruber et al., 2007). The algal concentration can be measured by retrieving their chlorophyll a concentration from remote sensing. The light signal measured from satellites needs to be corrected for various atmospheric and water surface effects. After atmospheric correction, the water leaving signal can be isolated and different algorithms exist to retrieve chlorophyll a. In open waters, blue-green ratios perform well (O’Reilly et al., 1998). In coastal waters, other water constituents (dissolved matter and sediments) make both the atmospheric correction process and the chlorophyll a estimates harder as they alter the light signal. Current chlorophyll algorithms therefore tend to perform poorly for turbid coastal waters. To develop a better algorithm, a northwest European shelf seas matchup dataset is built by collecting in situ chlorophyll a and MODIS Aqua sensor data. Different neural network algorithms are developed to make the best possible estimates of chlorophyll a, using either the bottom of atmosphere reflectance Rrs, commonly used by other algorithms, or top of atmosphere reflectances, when no atmospheric correction was applied to the light signal.It is found that the uncorrected top of atmosphere signal produces better and more reliable estimates over the entire dataset which contains mainly nearshore samples. Small neural network architectures containing 3 hidden layers of 15 neurons show good performances. The randomness involved in what a single neural network produces is tackled by using an ensemble approach of ten networks. The use of the whole light spectrum from 412 nm to 2130 nm produced the best estimates and should lead future dataset creations that currently do not include all available spectral information. The neural network algorithm developed here for chlorophyll a works well for turbid coastal waters where other algorithms either fail or mask out the data after applying quality control flags. The greatest impact is likely to be for nearshore waters where turbidity tends to be greatest. The approach developed here for NW European shelf seas has potential to be extended to global scale operation if a suitable training data set can be collected in future. The process is repeated for a modelled dataset and shows almost perfect estimates of the three different water constituents that alter the light signal. Temperature can also be estimated with better performance using the same approach which allows creation of a single temperature algorithm that works during both day and night, for any month and position on Earth. The benefit of using an enhanced chlorophyll a algorithm is later evaluated from the eutrophication assessment point of view. Remote sensing techniques produce several orders of magnitude more data than the current in situ approach to assess the eutrophication status and should help policymakers in producing coherent and improved assessment of the environment
Pre-breakdown ionization processes and impulsive breakdown characteristics of gases
Get PDFGlobal warming has become a central issue in the problem of environmental protection. Sulphur hexafluoride (SF6) has excellent insulation and recovery characteristics; however, this gas has significant Global Warming Potential ⁓23,900 times higher than CO2. Therefore, to reduce negative environmental impact caused by SF6 when this gas is released into atmosphere, the power and pulsed power industries are actively looking for alternative gases which can be used as insulating fluids in high voltage power and pulsed power systems. Therefore, there is an urgent need to establish breakdown properties and characteristics of common and environmentally friendlygases in different topologies and energisation regimes. Thus, further understanding of the transient pre-breakdown processes, dynamic properties of plasma streamers and experimental breakdown characteristics of common and environmentally friendly gases in a wide range of normalised pressures and electric fields is required. The present thesis addresses this issue through: (i) the systematic investigation and analysis of the swarm characteristics of air, N2, CO2, and SF6, (ii) the development of analytical models for investigation of fast ionization process in these gases, including drift-diffusion and kinetic models, (iii) the experimental investigation of the impulsive breakdown properties of air, N2, CO2 stressed with fast, sub-s high voltage impulses with a rise time of up to ~50 ns in the pressure range from 6.5 kPa to 405 kPa, and (iv) the analysis of breakdown properties of humid air with selected relative humidity. The present work has conducted a comprehensive analytical, computational and experimental investigation of transient events in common and environmentally friendly gases and their impulsive breakdown characteristics. The breakdown characteristics of the investigated gases have been obtained, and these data are presented as field-distance and time-field characteristics. These obtained results willhelp to optimize gaseous insulation for different power and pulsed power applications, the findings will contribute to a better understanding of the development of the fast pre-breakdown processes in gases. Thus, it will help to develop different gas-insulated components for the HV power and pulsed power systems, such as fast plasma closing switches filled with environmentally friendly gases and gas-insulated systems.Global warming has become a central issue in the problem of environmental protection. Sulphur hexafluoride (SF6) has excellent insulation and recovery characteristics; however, this gas has significant Global Warming Potential ⁓23,900 times higher than CO2. Therefore, to reduce negative environmental impact caused by SF6 when this gas is released into atmosphere, the power and pulsed power industries are actively looking for alternative gases which can be used as insulating fluids in high voltage power and pulsed power systems. Therefore, there is an urgent need to establish breakdown properties and characteristics of common and environmentally friendlygases in different topologies and energisation regimes. Thus, further understanding of the transient pre-breakdown processes, dynamic properties of plasma streamers and experimental breakdown characteristics of common and environmentally friendly gases in a wide range of normalised pressures and electric fields is required. The present thesis addresses this issue through: (i) the systematic investigation and analysis of the swarm characteristics of air, N2, CO2, and SF6, (ii) the development of analytical models for investigation of fast ionization process in these gases, including drift-diffusion and kinetic models, (iii) the experimental investigation of the impulsive breakdown properties of air, N2, CO2 stressed with fast, sub-s high voltage impulses with a rise time of up to ~50 ns in the pressure range from 6.5 kPa to 405 kPa, and (iv) the analysis of breakdown properties of humid air with selected relative humidity. The present work has conducted a comprehensive analytical, computational and experimental investigation of transient events in common and environmentally friendly gases and their impulsive breakdown characteristics. The breakdown characteristics of the investigated gases have been obtained, and these data are presented as field-distance and time-field characteristics. These obtained results willhelp to optimize gaseous insulation for different power and pulsed power applications, the findings will contribute to a better understanding of the development of the fast pre-breakdown processes in gases. Thus, it will help to develop different gas-insulated components for the HV power and pulsed power systems, such as fast plasma closing switches filled with environmentally friendly gases and gas-insulated systems
How financial technology innovation affects efficiency and equality in the UK financial regulatory system
No full textMechanistic characterisation of the Rh50 ammonium transporter protein from Nitrosomonas europaea
Get PDFThis thesis was previously held under Moratorium from 9th February 2023 until 9th February 2025.The exchange of ammonium across cellular membranes is a fundamental process in all domains of life which is facilitated by the ubiquitous Amt/Mep/Rh transporter superfamily. The functional diversity of Amt/Mep and Rh has been known for decades: bacteria, fungi, and plants use Amt/Mep proteins to scavenge ammonium for biosynthetic assimilation. Mammals on the other hand use the Rh proteins for ammonium detoxification in erythrocytes, kidney, and liver tissues. Crucially Rh malfunction is associated with various pathologies, including hereditary anaemias, overhydrated stomatocytosis, and early-onset depressive disorders. However, their mechanism and the substrate translocated (NH4 + /NH3) remain elusive. Recently, our group proposed a new model for the mechanism of electrogenic ammonium transport in AmtB protein from E. coli, where NH4 + undergoes deprotonation, allowing NH3 and H+ to follow two separate pathways, and join in the cytoplasm. Despite their fundamentally divergent physiological functions, the Amt/Mep/Rh proteins are structurally very similar, raising the possibility of a conserved transport mechanism across the family. In this context, we investigated the mechanism of ammonium translocation through rhesus protein (Rh50) from Nitrosomonas europaea, as a first step towards expanding the Rh protein research and understanding of their mechanism. An in vitro assay based on Solid Supported Membrane Electrophysiology (SSME) was developed and the electrogenic activity in Rh50 was confirmed (Chapter 3). We provided a detailed characterisation of the activity, selectivity, and kinetics of WT Rh50 (Chapter 4). Further characterisation of WT Rh50 and Rh50 variants led to the proposal of the coexistence of two mechanisms in the protein: mechanism I wherein NH4 + is deprotonated and H+ and NH3 are carried separately across the membrane, and mechanism II, where NH4 + is directly translocated through by-passing deprotonation (Chapter 4). Through mutagenesis studies, we also revealed valuable information on bidirectionality of the protein which we propose to be directly linked with a hydration pattern of the protein (Chapter 5). The body of this work provides a basis for future Rh protein research which will enable us to better understand how Rh mutations lead to pathologies in humans.The exchange of ammonium across cellular membranes is a fundamental process in all domains of life which is facilitated by the ubiquitous Amt/Mep/Rh transporter superfamily. The functional diversity of Amt/Mep and Rh has been known for decades: bacteria, fungi, and plants use Amt/Mep proteins to scavenge ammonium for biosynthetic assimilation. Mammals on the other hand use the Rh proteins for ammonium detoxification in erythrocytes, kidney, and liver tissues. Crucially Rh malfunction is associated with various pathologies, including hereditary anaemias, overhydrated stomatocytosis, and early-onset depressive disorders. However, their mechanism and the substrate translocated (NH4 + /NH3) remain elusive. Recently, our group proposed a new model for the mechanism of electrogenic ammonium transport in AmtB protein from E. coli, where NH4 + undergoes deprotonation, allowing NH3 and H+ to follow two separate pathways, and join in the cytoplasm. Despite their fundamentally divergent physiological functions, the Amt/Mep/Rh proteins are structurally very similar, raising the possibility of a conserved transport mechanism across the family. In this context, we investigated the mechanism of ammonium translocation through rhesus protein (Rh50) from Nitrosomonas europaea, as a first step towards expanding the Rh protein research and understanding of their mechanism. An in vitro assay based on Solid Supported Membrane Electrophysiology (SSME) was developed and the electrogenic activity in Rh50 was confirmed (Chapter 3). We provided a detailed characterisation of the activity, selectivity, and kinetics of WT Rh50 (Chapter 4). Further characterisation of WT Rh50 and Rh50 variants led to the proposal of the coexistence of two mechanisms in the protein: mechanism I wherein NH4 + is deprotonated and H+ and NH3 are carried separately across the membrane, and mechanism II, where NH4 + is directly translocated through by-passing deprotonation (Chapter 4). Through mutagenesis studies, we also revealed valuable information on bidirectionality of the protein which we propose to be directly linked with a hydration pattern of the protein (Chapter 5). The body of this work provides a basis for future Rh protein research which will enable us to better understand how Rh mutations lead to pathologies in humans
Fast fluorescence lifetime imaging and sensing via deep learning
Get PDFFluorescence lifetime imaging microscopy (FLIM) has become a valuable tool in diverse disciplines. This thesis presents deep learning (DL) approaches to addressing two major challenges in FLIM: slow and complex data analysis and the high photon budget for precisely quantifying the fluorescence lifetimes. DL's ability to extract high-dimensional features from data has revolutionized optical and biomedical imaging analysis. This thesis contributes several novel DL FLIM algorithms that significantly expand FLIM's scope.Firstly, a hardware-friendly pixel-wise DL algorithm is proposed for fast FLIM data analysis. The algorithm has a simple architecture yet can effectively resolve multi-exponential decay models. The calculation speed and accuracy outperform conventional methods significantly.Secondly, a DL algorithm is proposed to improve FLIM image spatial resolution, obtaining high-resolution (HR) fluorescence lifetime images from low-resolution (LR) images. A computational framework is developed to generate large-scale semi-synthetic FLIM datasets to address the challenge of the lack of sufficient high-quality FLIM datasets. This algorithm offers a practical approach to obtaining HR FLIM images quickly for FLIM systems.Thirdly, a DL algorithm is developed to analyze FLIM images with only a few photons per pixel, named Few-Photon Fluorescence Lifetime Imaging (FPFLI) algorithm. FPFLI uses spatial correlation and intensity information to robustly estimate the fluorescence lifetime images, pushing this photon budget to a record-low level of only a few photons per pixel.Finally, a time-resolved flow cytometry (TRFC) system is developed by integrating an advanced CMOS single-photon avalanche diode (SPAD) array and a DL processor. The SPAD array, using a parallel light detection scheme, shows an excellent photon-counting throughput. A quantized convolutional neural network (QCNN) algorithm is designed and implemented on a field-programmable gate array as an embedded processor. The processor resolves fluorescence lifetimes against disturbing noise, showing unparalleled high accuracy, fast analysis speed, and low power consumption.Fluorescence lifetime imaging microscopy (FLIM) has become a valuable tool in diverse disciplines. This thesis presents deep learning (DL) approaches to addressing two major challenges in FLIM: slow and complex data analysis and the high photon budget for precisely quantifying the fluorescence lifetimes. DL's ability to extract high-dimensional features from data has revolutionized optical and biomedical imaging analysis. This thesis contributes several novel DL FLIM algorithms that significantly expand FLIM's scope.Firstly, a hardware-friendly pixel-wise DL algorithm is proposed for fast FLIM data analysis. The algorithm has a simple architecture yet can effectively resolve multi-exponential decay models. The calculation speed and accuracy outperform conventional methods significantly.Secondly, a DL algorithm is proposed to improve FLIM image spatial resolution, obtaining high-resolution (HR) fluorescence lifetime images from low-resolution (LR) images. A computational framework is developed to generate large-scale semi-synthetic FLIM datasets to address the challenge of the lack of sufficient high-quality FLIM datasets. This algorithm offers a practical approach to obtaining HR FLIM images quickly for FLIM systems.Thirdly, a DL algorithm is developed to analyze FLIM images with only a few photons per pixel, named Few-Photon Fluorescence Lifetime Imaging (FPFLI) algorithm. FPFLI uses spatial correlation and intensity information to robustly estimate the fluorescence lifetime images, pushing this photon budget to a record-low level of only a few photons per pixel.Finally, a time-resolved flow cytometry (TRFC) system is developed by integrating an advanced CMOS single-photon avalanche diode (SPAD) array and a DL processor. The SPAD array, using a parallel light detection scheme, shows an excellent photon-counting throughput. A quantized convolutional neural network (QCNN) algorithm is designed and implemented on a field-programmable gate array as an embedded processor. The processor resolves fluorescence lifetimes against disturbing noise, showing unparalleled high accuracy, fast analysis speed, and low power consumption
Automated quantitative inspection of nuclear assets and canisters
Get PDFStructural integrity of nuclear assets and their associated infrastructure is key to national security, energy generation, and efficient deployment of capital. Furthermore, building nuclear infrastructure is inherently complex and it is common to seek extensions in asset and infrastructure lifetime as they age. Therefore, this thesis explores various Non-Destructive Evaluation (NDE) techniques to advance the inspection of nuclear canisters and their welds for three scenarios: 1) In-situ screening of legacy canisters sealed by Resistance Seam Welds (RSWs) while on a racking system with considerable accessibility constraints; 2) Ex-situ characterisation of legacy canisters sealed by RSWs; & 3) Inspection of fusion welds performed via Gas Tungsten Arc Welding (GTAW) for an upgraded canister of the future design at the point of manufacture. For the in-situ scenario a unique ultrasonic guided wave, a Feature Guided Wave (FGW), was exploited to screen the legacy RSW. For the RSW, four weld-guided wave modes were identified, and the fundamental flexural (F0) weld guided mode was down selected. Several Finite Element (FE) models explored applicable transduction strategies and documented reflection coefficients from transverse cracks. Multiple experiments were conducted on pseudo RSW structures as well as flat plate and cylindrical RSWs. For the pseudo weld experiments, it was shown that FGWs, like that of the analytical free plate counterparts, could easily be excited in flat plate-like features with traditional transduction techniques. For the flat plate RSW experiments, it was shown that reflections from 6.5 mm wide through wall and 1.00 mm deep defects could be observed with Signal to Noise Ratios (SNRs) of 16.33 dB and 8.21 dB respectively. Lastly, it was shown that for cylindrical canister like RSWs, reflections could also be observed from 1.00 mm deep defects with a SNR of 11.85 dB being reported. This work clearly showed the benefit of deploying such a system on-site at Sellafield as full circumferential screening of the RSW could be performed giving greater insight to the structural health of the canisters in-situ. To address the ex-situ inspection of the legacy canister, an automated robotic eddy current system was developed. The data rich platform allowed for a complete digital record to be established of the impedance data gathered and is well suited for further advancements in eddy current inversion to leverage in the future. The robotic deployment of the eddy current array was combined with force torque feedback and enabled major sources of noise, resulting from lift-off and wobble, to be reduced. Two different datasets were reported on. The first being eddy current scans of canister bodies with known stress corrosion cracks. All of the stress corrosion cracks were detected, and the resulting SNR of images generated from the impedance data was increased through post processing of the eddy current data. The second dataset is concerned with eddy current scans of RSWs. These scans make use of the aforementioned FGW, to localise defects and perform targeted raster scans in the area of concern. Basic inversion on the EDM notch width was shown to give results with 96.4% accuracy, and it was shown that time savings of up to ~95% could be realised by performing targeted eddy current raster scans. This work clearly shows the benefit of performing an ex-situ inspection in this manner due to the minimal levels of operator handling and time savings that can be realised on large production volumes like that at Sellafield. Lastly, inspection of the envisaged canister of the future design at the point of manufacture was explored as it would enable operational efficiencies and the ability to be able to create a Non-Destructive Evaluation (NDE) digital twin to monitor the structural health of the component over its lifetime. Technically, inspecting welded components at the point of manufacture is challenging due to the elevated temperature and resulting thermal gradients in the component introducing beam bending effects due to refraction and positional inaccuracies in the ultrasonic data. A novel thermal compensation strategy was developed that leveraged thermal weldment simulations to correct for positional inaccuracies. Initially, the thermal compensation strategy was trialled on simulated data and the positional accuracy was shown to increase by at least 85%. Experimental results also showed a similar trend with a 63.6% improvement in reflector positional accuracy. The results show how high-quality ultrasonic images can be generated at the point of manufacture and how a similar strategy could be deployed to establish an inspection record from manufacture until the asset is retired.Structural integrity of nuclear assets and their associated infrastructure is key to national security, energy generation, and efficient deployment of capital. Furthermore, building nuclear infrastructure is inherently complex and it is common to seek extensions in asset and infrastructure lifetime as they age. Therefore, this thesis explores various Non-Destructive Evaluation (NDE) techniques to advance the inspection of nuclear canisters and their welds for three scenarios: 1) In-situ screening of legacy canisters sealed by Resistance Seam Welds (RSWs) while on a racking system with considerable accessibility constraints; 2) Ex-situ characterisation of legacy canisters sealed by RSWs; & 3) Inspection of fusion welds performed via Gas Tungsten Arc Welding (GTAW) for an upgraded canister of the future design at the point of manufacture. For the in-situ scenario a unique ultrasonic guided wave, a Feature Guided Wave (FGW), was exploited to screen the legacy RSW. For the RSW, four weld-guided wave modes were identified, and the fundamental flexural (F0) weld guided mode was down selected. Several Finite Element (FE) models explored applicable transduction strategies and documented reflection coefficients from transverse cracks. Multiple experiments were conducted on pseudo RSW structures as well as flat plate and cylindrical RSWs. For the pseudo weld experiments, it was shown that FGWs, like that of the analytical free plate counterparts, could easily be excited in flat plate-like features with traditional transduction techniques. For the flat plate RSW experiments, it was shown that reflections from 6.5 mm wide through wall and 1.00 mm deep defects could be observed with Signal to Noise Ratios (SNRs) of 16.33 dB and 8.21 dB respectively. Lastly, it was shown that for cylindrical canister like RSWs, reflections could also be observed from 1.00 mm deep defects with a SNR of 11.85 dB being reported. This work clearly showed the benefit of deploying such a system on-site at Sellafield as full circumferential screening of the RSW could be performed giving greater insight to the structural health of the canisters in-situ. To address the ex-situ inspection of the legacy canister, an automated robotic eddy current system was developed. The data rich platform allowed for a complete digital record to be established of the impedance data gathered and is well suited for further advancements in eddy current inversion to leverage in the future. The robotic deployment of the eddy current array was combined with force torque feedback and enabled major sources of noise, resulting from lift-off and wobble, to be reduced. Two different datasets were reported on. The first being eddy current scans of canister bodies with known stress corrosion cracks. All of the stress corrosion cracks were detected, and the resulting SNR of images generated from the impedance data was increased through post processing of the eddy current data. The second dataset is concerned with eddy current scans of RSWs. These scans make use of the aforementioned FGW, to localise defects and perform targeted raster scans in the area of concern. Basic inversion on the EDM notch width was shown to give results with 96.4% accuracy, and it was shown that time savings of up to ~95% could be realised by performing targeted eddy current raster scans. This work clearly shows the benefit of performing an ex-situ inspection in this manner due to the minimal levels of operator handling and time savings that can be realised on large production volumes like that at Sellafield. Lastly, inspection of the envisaged canister of the future design at the point of manufacture was explored as it would enable operational efficiencies and the ability to be able to create a Non-Destructive Evaluation (NDE) digital twin to monitor the structural health of the component over its lifetime. Technically, inspecting welded components at the point of manufacture is challenging due to the elevated temperature and resulting thermal gradients in the component introducing beam bending effects due to refraction and positional inaccuracies in the ultrasonic data. A novel thermal compensation strategy was developed that leveraged thermal weldment simulations to correct for positional inaccuracies. Initially, the thermal compensation strategy was trialled on simulated data and the positional accuracy was shown to increase by at least 85%. Experimental results also showed a similar trend with a 63.6% improvement in reflector positional accuracy. The results show how high-quality ultrasonic images can be generated at the point of manufacture and how a similar strategy could be deployed to establish an inspection record from manufacture until the asset is retired
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