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Novel power electronic systems with embedded energy storage and renewable energy generation
Full text linkMagnetic Induction Tomography using Vector Spherical Harmonic Magnetic Fields and Quantum Sensing
Full text linkThe work explores the use of spherical harmonic magnetic vector fields in magnetic induction tomography, an eddy current based non-ionising imaging technique. It uses the spherical harmonic magnetic fields as primary excitor fields, creating orthogonal sensitivity matrices ensuring efficient and accurate image reconstruction using two different algorithms. The thesis further explores the phase of the eddy current induced secondary magnetic fields and seeks to use phase in image reconstruction. Lastly, the thesis seeks to measure the eddy current induced secondary magnetic fields from low conductivity materials using quantum sensors known as optically pumped magnetometers
Different eras of council housing estates and their neighbourhood formation: the case of Nottingham
Full text linkThis thesis investigates how council housing estates, developed during different historical periods, have influenced neighbourhood formation and the production of lived space. Using Lefebvre’s spatial triad (conceived, perceived, and lived space) as a framework, the study reveals how large-scale social housing projects shape spatial configurations, social interactions, and community dynamics. It also assesses how planning and design decisions have contributed to neighbourhood formation, highlighting the role of housing policies in fostering social cohesion and neighbourhood vitality.
This research adopts a mixed-method approach to examine the spatial and social dynamics of council housing estates built in different historical periods. The study utilises space syntax analysis, observation and rhythmanalysis to investigate four distinct neighbourhoods in Nottingham. The spatial configuration of each area is analysed through integration and choice measurements, followed by field observations along the main integrated routes.
Rhythmanalysis is applied to reveal the temporal and spatial rhythms of daily life, while census data is used to explore the socio-demographic characteristics of the communities.
The findings revealed that the interwar estate, though well integrated with the city, failed to foster social interaction due to low spatial integration and limited functional diversity at the local level, leading to social isolation. The late 20th-century estate exhibited a segregated structure in both spatial configuration and functional diversity. The postwar estate, despite being located on the periphery, encouraged more interaction among residents, owing to higher local integration, making it the most successful example in terms of urban qualities. Due to its central location, the high-rise period example provided important data on living in the city centre. Constructed as a mixed-use, modern residential structure in the city centre, the flats supported residents' direct access to city amenities while revealing how the streetscape changed due to the changing land use patterns in the surrounding streets with high integration values.
This study advances the understanding of urban spatial dynamics in council housing estates and provides an understanding of future urban planning policies to improve community cohesion and spatial design in suburban areas
Assessing the Efficacy of a Bacteriophage Cocktail, Comprised of Three Monophages, Against Campylobacter spp. in Broiler Chickens
Full text linkCampylobacter species are the leading cause of foodborne illness across the globe, with chicken meat being the main source of infection. The development of resistance, by campylobacters, to key antibiotics limits the treatment options for consumers, heightening the need to prevent transmission to humans in the first instance. This study was conducted to assess the efficacy of a bacteriophage cocktail, named CampyShield, in reducing Campylobacter counts in the caeca and liver of broiler chickens. The efficacy of CampyShield in Campylobacter reduction was compared with that of CP30A (a commonly used Campylobacter bacteriophage). Firstly, 160 trial birds were allocated to treatment groups, as described in section 2.6., and were infected with CampyShield, CP30A and Campylobacter to assess the extent of Campylobacter reduction in the caeca. Campylobacter phage-resistant isolates from the birds, were then detected, post-trial, and subjected to various resistance tests such as sensitivity testing to the CampyShield cocktail phages and CP30A, motility testing and carrier state testing. Phage-resistant isolates were also sequenced to identify phase variation, conferring resistance mechanisms. The detection of CampyShield and the presence of Campylobacter in the liver of trial birds was then discussed, to assess whether there was translocation by either entity from the caeca of the broiler chickens into the liver and to assess the efficacy of CampyShield in the liver. Lastly, in vitro investigations were carried out on the CampyShield constituent phages against Campylobacter strains to further determine the efficacy of the cocktail. These investigations included measuring host strain diversity, calculating efficiency of plating (EOP) values against certain strains and measuring the extent of resistance to the CampyShield constituent phages, by C. jejuni NCTC 12662, after 24 h. DNA sequences of these resistant strains were also obtained, to identify resistance mechanisms through phase variation.
In summary, the CampyShield cocktail lacked efficacy in several regards, due to individual drawbacks of its constituent phages. For example, CampyShield experienced a much higher resistance level in the caeca compared to that of CP30A, only one third of the constituent phages was able to translocate to the liver and CampyShield experienced a high level of resistance by C. jejuni NCTC 12662 lab stock isolates in vitro
Caged Compounds: A Novel Synthesis of Homocubane and its Analogues and Gold-(I) Catalysed Propargylation of Azinium Salts
No full textWe disclose a novel synthetic method to access the homocubane ester 4a in 4 steps, in an overall yield comparable or superior to literature methods. The sequential transformations of a [6+2] cycloaddition, 4π electrocyclisation, followed by a dehydrogenation and [2+2] cycloaddition displays the relatively simple route to access this challenging to make structure. We also inadvertently synthesised an interesting polycyclic structure we have tentatively assigned as formal [4+2] product 6.
Herein, we report the development of a methodology for the regioselective 1,4-addition of propargyl boronates to a range of N-alkylated pyridinium, quinolinium, and pyrazinium salts, through gold-(I) mediated catalysis. A variety of functionality is tolerated under the mild reaction conditions, and an attempt to rationalise the mechanism has been realised with the assistance of DFT studies. Further potential chemical transformations have also been conducted, which, when combined with the work conducted in this study, pave the way for exploration into underdeveloped and diverse chemical space
Advanced control strategies for PMSM drive system in high-performance electric racing application
No full textThis thesis presents advanced control strategies to improve the dynamic performance and efficiency of Silicon Carbide (SiC)-based Permanent Magnet Synchronous Motor (PMSM) drive systems, specifically for high-performance electric racing applications. It begins with the development of a comprehensive analytical loss model that captures the nonlinear behaviour of both the machine and power electronics. This model offers detailed insights into energy dissipation and serves as the foundation for optimising -axis current references. Experimental validation shows that predicted system losses align with measurements within a Normalized Root Mean Square Error (NRMSE) below 5\%, confirming its suitability for efficiency optimisation.
Building on this, an online polynomial fitting-based Loss Minimisation (LM) strategy is introduced. This method enables real-time adjustment of the -axis current without relying on precomputed lookup tables, significantly improves flexibility. It maintains a tracking error within 0.5\% under rated load and reaches the optimal operating point within a single control cycle, whereas conventional online methods may take up to 1500 cycles to converge.
The LM strategy is then integrated with Finite Control Set Model Predictive Control (FCS-MPC), resulting in notable gains in both dynamic response and energy efficiency. By reducing switching losses, it achieves up to 1.1kW loss reduction at rated load. To enhance robustness, an online parameter estimation method using virtual small signal injection is proposed. This method identifies key parameters—inductance, resistance, and flux linkage—with just 82 floating-point operations per cycle, ensuring fast, real-time adaptation and mitigating the effects of parameter mismatch.
Finally, the LM strategy is embedded in an enhanced Model Predictive Torque Control (MPTC) framework, unifying torque and loss control in a single loop. Experimental results show tracking accuracy within 2\% and a dramatic reduction in dynamic settling time—from over 10ms in conventional online LM methods to just 0.17ms with the proposed strategy—demonstrating a substantial improvement in transient performance
An innovative reputation system for trustworthy and secure vehicle-to-vehicle communication
Full text linkVehicular Ad Hoc Networks (VANETs) are a promising technology that ensures secure and efficient transportation by allowing vehicles to seamlessly communicate with each other and with infrastructure to share real-time information and make better decisions while travelling. However, determining which information is accurate under certain circumstances, such as in the event of an accident, may become challenging when receiving messages from multiple nearby vehicles. Therefore, trusting these messages requires a reliable and secure system to guard against insider attackers, who may intentionally send misleading information, particularly in scenarios without extensive Roadside Units (RSUs) to mediate these exchanges.
Existing standards, such as the Security Credential Management System (SCMS), supply vehicles with pseudonym certificates to meet security and privacy requirements. However, this system has difficulties ensuring that the revoked certificates are updated in regions with limited connectivity access. In order to solve this issue, this research proposes a novel reputation system to maximise the chance of making an accurate decision based on the received messages. This builds upon existing standards and specifications to integrate an innovative Pre-Signature scheme for effective reputation dissemination.
The Pre-Signature scheme enables vehicles to assess dynamically and rely on the most trustworthy information available, even in challenging and limited environments. The research develops realistic simulations of 24-hour rural scenarios to replicate real-time communication challenges. The simulation work also includes accident and malicious attack scenarios, thus giving a wide-ranging performance evaluation of the Pre-Signature scheme under typical infrastructural constraints. The results revealed a significant enhancement in decision-making accuracy with conflicting information, achieving an improvement ranging from 36% in Accidents and 44.4% in No-Accident scenarios in a rural environment compared to the existing certification system.
Finally, a new reporting scheme, Distributed Reputation for Accurate Vehicle Misbehaviour Reporting (DRAMBR), is proposed to improve reporting efficiency in disconnected areas by effectively mitigating false reports while distinguishing between honest reporters, system errors and malicious behaviours. Experimental results indicate that the DRAMBR system achieves 98% effectiveness in distinguishing between behaviours, highlighting its overall performance.
The contribution of the thesis is related to the development of VANETs, in particular, to improve the reliability and efficiency of V2V communications in critical areas, enabling safer, more secure, and efficient transport networks
Determining the functions of the pre-Old English runic inscriptions
Full text linkThis thesis offers a comprehensive analysis of the pre-Old English runic corpus (PrOERC)—runic inscriptions from Britain between c. 400 and 650 AD—to investigate the functions of the runic script. Two overarching research questions guide this study: what are the functions of runic script, and how can those functions be identified?
Previous research has largely approached these inscriptions from a neo-Grammarian perspective, focusing on phonological, morphological, and syntactic analysis to determine meaning. This approach has led to uneven results: while some inscriptions could be ‘read’ and their functions inferred, others, particularly the non-lexical texts that make up nearly a third of the corpus, could not be analysed in the same way. Non-lexical inscriptions do not form words and, as such, were often excluded from functional interpretation.
The field of runology, the study of runic inscriptions, has recently embraced more context-focused methodologies, including semiotics, sociolinguistics, and pragmatics. This thesis evaluates the applicability of pragmatics as a methodological framework for analysing runic inscriptions, concluding that while pragmatics is a valuable tool, it requires methodological adaptation for this purpose. The study employs a pragmatics-informed approach, dividing its analysis into two complementary areas: linguistic analysis and contextual analysis. The linguistic analysis focuses on lexical inscriptions, identifying formulae based on their structural patterns and assigning communicative functions accordingly. The contextual analysis applies pragmaphilology, a methodology that considers contextual factors such as the roles of the text producer and receiver to determine function. Both lexical and non-lexical inscriptions undergo this contextual examination.
This thesis reaches significant conclusions about the functions of inscriptions within the PrOERC. Lexical texts exhibit a variety of functions, typically expressed through formulae dominated by personal names. These formulae often reflect the relationship between the rune-bearing object and the individual(s) mentioned in the text. Non-lexical texts, on the other hand, derive their functions primarily from their interaction with the rune-bearing object, mimicking the functions of lexical texts in similar contexts. The findings underscore the necessity of a context-forward analysis for each inscription to fully understand the functions of runic script in the corpus
Genetic analysis Of self-incompatibility in Petunia and Stumberger
Full text linkSelf-incompatibility (SI) is a widespread genetic mechanism which prevent self-fertilization in angiosperms. The genus Petunia of the Solanaceae serve as a model for SI research due to its short life cycle and accessible floral morphology. In Petunia, SI is mediated by S-RNase dependent degradation of self-pollen RNA within the style, arresting pollen tube growth. Breakdown of SI confers self-compatibility (SC), with implications for breeding and yield optimization.
This study investigates the genetic basis of SI breakdown in hybrids of P. inflata × P. hybrida. For the first time, it provides a concise analysis of the novel PiSd-allele and its association with SC across five generations. Genotypic and phenotypic analyses, including genomic PCR, identification of S-alleles by sequencing, and controlled self-pollinations were performed on lines carrying PhS3 and PiSd alleles.
The novel PiSd allele correlates with SI breakdown, suggesting functional alteration in associated SLF genes, which remain uncharacterized. The segregation ratios confirm the linkage between the PiSd and SI breakdown. Future molecular dissection of PiSd-linked SLF genes will firstly provide an understanding of the mechanism of SI breakdown and ultimately is warranted to inform targeted breeding strategies in Petunia and beyond.
The second stage of this research is focused on SI mechanism in Schlumbergera truncata. S. truncata is among the most widely cultivated cactus species notable for its diverse array of colourful flowers and various flower forms. SI in S. truncata is under GSI control. This study tests whether the GSI mechanism in S. truncata is of the S-RNase system and explores whether it is homologous to that in the rosids and the asterids, as it likely seems by the phylogenetic relationships of angiosperms. This was achieved by analysing the genetic and phenotypic characteristics of different lines, determining the presence and functionality of S-alleles within the study lines.
This study successfully identified three S-alleles in the S. truncata F1 progeny lines. All three are present in the five alleles identified previously. These S alleles identification combined with the data of the classic diallele self and cross-pollination and the formed incompatibility/compatibility groups strongly suggest the likelihood of a S-RNase mechanism under the control of a single locus occurring in the S. truncata population.
These findings in S. truncata combined contribute to a deeper understanding that the S-RNase mechanism is more widely functional and polymorphic among angiosperms, which adds to the insights of their evolutionary relationships. A question for future study is whether this mechanism is functional through self-recognition or non-self-recognition pathways
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