8,264 Works

Tunable nano-plasmonic metamaterials at solid-liquid and liquid-liquid interfaces

Ye Ma
Metamaterials have demonstrated their unusual optical properties, ranging from negative refractive index to optical nonlinearity. Real-time adjustment of these properties becomes critical for the next generation of ‘smart’ optical devices. In this thesis, different methods for actively tuning the structure and output of metamaterials are demonstrated. These metamaterials consist of metallic nanoparticles (NPs) at solid-liquid interfaces (SLIs) and liquid-liquid interfaces (LLIs). Electrically, the assembly of gold NPs at a SLI is reversibly controlled by changing...

Looking beyond the leaves and understanding the roots: sustainability assessment and monitoring of planted forests for biomass production in Brazil

Manuela De Moraes Czinar
Whereas most of the recent literature is concerned about the output legitimacy of planted forests, this thesis focus on the input legitimacy. The novel framework proposed in this thesis uses association membership and technical support as indicators of the sustainable expansion of planted forests from the lens of input legitimacy. This framework was based on the results of the grounded theory method applied to semi-structured interviews carried out with stakeholders in Brazil. Quantitative data were...

Identifying host-pathogen interactions which cause severe malaria

Athina Georgiadou
Infectious diseases pathogenesis is dependent on the interactions between the host and the pathogen. Being able to simultaneously assess the transcriptomes of both host and pathogen as we have shown here, using dual RNA sequencing of whole blood from Plasmodium falciparum malaria patients, can reveal these crucial interactions. Using Gambian children samples we tried to unravel the mechanisms leading to severe malaria. The main finding was the clear involvement of neutrophil related genes in severe...

Sensitivity analysis, uncertainty quantification and parameter estimation for a numerical tide and storm surge model

Simon Charles Warder
Storm surges pose a significant hazard to coastal communities worldwide. Accurate and reliable storm surge numerical models, combined with an understanding of model uncertainties, are therefore vital. In this work, an adjoint-capable numerical coastal ocean model, Thetis, is extended and used to perform a sensitivity analysis for a hindcast case study in the North Sea, revealing the spatial patterns of the sensitivity of modelled surges to three model inputs. These sensitivities are used to gain...

The role of the general stress response in staphylococcal survival during exposure to host immune defences and antibiotics

Nishanthy Ranganathan
Persistent staphylococcal bacteraemia remains an important and frequent cause of morbidity and mortality, despite the availability of apparently effective antimicrobial therapy. Antibiotic tolerance is poorly characterised since despite bacteria being able able to survive prolonged antibiotic exposure without the acquisition of resistance mutations, they are found to be sensitive to antibiotics in vitro. SigB is a global regulator involved in the response of staphylococcal bacteria against acid, heat, salt and alcohol stresses. The majority of...

The Th17 pathway in Cystic Fibrosis lung disease

Hui-Leng Tan
In contrast to the neutrophilic inflammation found in the airway lumen, lymphocytes predominate in the airway wall of Cystic fibrosis (CF) patients. The Th17 pathway could play an important role in CF, as IL-17, secreted by Th17 lymphocytes, is proinflammatory, stimulates neutrophil recruitment and has been detected in CF sputum. This thesis investigates the hypothesis that T lymphocytes, in particular Th17 lymphocytes, are present in the CF airway wall and activation of the Th17 pathway...

On delamination directionality and migration in laminated composites

Carla Canturri Gispert
Delamination is recognised as the most critical damage process in laminated composites under compressive or bending loading conditions and managing this failure mode has been key to using composites in primary structures. However, predictive modelling of delamination growth has been limited, since even a simple, single plane defect can result in multiplane delamination growth which is often associated to other secondary processes such as intralaminar or translaminar damage. The objective of this thesis has been...

PET studies in Parkinson’s Disease Dyskinesias and Dementia

Imtiaz Ahmed
Parkinson’s disease is the second most common neurodegenerative disease in the world. The initial motor symptoms are well controlled with replacement therapy with levodopa. Slowly over time the patients run into problems both due to the inexorable progression of the disease and also due to complications of the drugs itself. The two most common disabling complications that are difficult to treat are levodopa-induced-dyskinesias and dementia. Although there have been extensive research, the pathophysiology of both...

Development of High Strain Rate Mechanical Testing for Metallic Materials

Michael Cox
Recent developments of high strain rate servo-hydraulic systems and high speed video imaging equipment have made the simple tensile test covering the quasi-static to dynamic range possible. However, obtaining reliable material data from the raw data produced from such tests requires a good understanding of the unique set of problems this testing technique can present. Tensile tests covering the quasi-static to 760 s-1 strain rate range were performed on Oxygen Free Electrolytic (OFE) copper, Al...

Queueing network models of zoned RAID system performance

Abigail Lebrecht
RAID systems are widely deployed, both as standalone storage solutions and as the building blocks of modern virtualised storage platforms. An accurate model of RAID system performance is therefore critical towards fulfilling quality of service constraints for fast, reliable storage. This thesis presents techniques and tools that model response times in zoned RAID systems. The inputs to this analysis are a specified I/O request arrival rate, an I/O request access profile, a given RAID configuration...

Asthma induced exacerbation of bacterial pneumonia.

Maryam Habibzay
Asthma and bacterial pneumonias are major causes of human mortality and morbidity throughout the world. To date many studies have investigated the possibility that bacteria exacerbate asthma but only a handful consider that asthma may cause bacterial infections. Recent clinical evidence suggests that bacterial infections cause serious complications in patients with asthma and that asthmatics show a 2-fold increased risk of invasive pneumococcal disease. This thesis examines the molecular mechanisms causing susceptibility of house dust...

Spatiotemporal visual analysis of human actions

Antonios Oikonomopoulos
In this dissertation we propose four methods for the recognition of human activities. In all four of them, the representation of the activities is based on spatiotemporal features that are automatically detected at areas where there is a significant amount of independent motion, that is, motion that is due to ongoing activities in the scene. We propose the use of spatiotemporal salient points as features throughout this dissertation. The algorithms presented, however, can be used...

Distributed optimisation in dynamic wireless sensor networks

Shusen Yang
Over the past decade, Wireless Sensor Networks (WSNs) have evolved into a hot interdisciplinary research area. WSNs are generally considered to be statically deployed, but in reality they are dynamic in nature due to a variety of characteristics including fluctuating wireless link quality and clock drift. Furthermore, new WSN topologies and applications have introduced more dynamics, such as time-varying power resources, data traffic patterns, and mobile sensing. These dynamics pose challenges to the theoretical understanding...

Soil microbial interactions affecting enteric pathogen survival in sewage sludge-amended agricultural soil

Felipe Perez Viana
The natural inactivation of enteric pathogens in soil is a critical component of the multi-barrier approach to prevent infectious disease in humans by enteric microorganisms when biosolids are used as a fertiliser and soil conditioner on agricultural land. The addition of biosolids to agricultural soil modifies the soil microbial community and ecological interactions. Ecological processes, especially the activities of predatory protozoa, may have a critical role in reducing the survival of enteric pathogenic bacteria when...

Majorana Representations and the Coxeter Groups G^(m,n,p)

Sophie Decelle
The work presented in this thesis is a contribution to Majorana theory as introduced by A. A. Ivanov in [Iva09]. Inspired by a theorem of S. Sakuma [Sak07], Majorana theory is an axiomatisation of seven properties of the Monster algebra VM, invariant under the Monster group M, and of some of its idempotents. For a finite group G generated by a G-invariant set T of involutions one can define what it means for G to...

Robustness of multi-storey steel-composite structures under localised fire

Cheng Fang
While current assessment methods for preventing progressive collapse are mainly associated with blast and impact loading, no systematic framework is currently available for the practical and rational assessment of robustness of multi-storey building structures under localised fire. In this thesis, a robustness assessment framework with various alternative levels of sophistication is presented with the aim of bridging the gap between the topics of structural fire resistance and progressive collapse. The robustness assessment framework developed in...

Architectural innovation and design evolution: strategic and organizational dynamics of industry platforms

Richard Liong Gie Tee
The importance of understanding changes in the underlying architecture of complex systems has been well established, both in the academic and practitioner literature. Though existing research has made significant advances, important issues remain. Generally, existing research on architectural change has tended to overlook the interplay between environmental and firm-level drivers. In particular, relatively few studies have looked at the challenges firms face in making architectural design choices, and contingencies arising out of architectural change. As...

Improved Performance of CaO-Based Sorbent for CO2 Capture

John Blamey
Calcium looping is a CO2 capture technology that is currently being developed on a 1 MWth pilot-scale. It has advantages including the ability to reclaim high-grade heat, the use of a relatively inexpensive, abundant and benign sorbent, and the potential to de-carbonise both power generation and cement manufacture. It makes use of the reversible carbonation of CaO to remove CO2 from a flue gas and provide pure CO2 for compression and storage, in a cyclical...

Novel approaches to statistical shape modelling of bone

Angelo Tardugno
The femur is the longest bone in the human body and serves the important purposes of load-bearing and allowing bipedal locomotion. Accurate modelling of the variation in shape within the healthy adult population can be useful for a variety of applications: from the mere anatomical description of its features, in order to better understand its function, to more complex tasks such as pathology detection or surgical planning. Statistical Shape Modelling (SSM) is a well-established technique...

Hybrid Scene Characterisation Applied to Natural Images

Georgios Sakellariou
In this thesis, a combination of skeletonisation and graph matching techniques, coupled with a blend of supervised and unsupervised learning methodology is applied to the task of characterising and classifying natural shapes. A novel navigation-based skeletonisation algorithm is used to gather low level structural and morphological information about the shape. Subsequently, the data are converted into a series of attributed graphs, which characterise the image. Graphs of the same type can then be compared using...

A Virtual Grain Structure Representation System for Micromechanics Simulations

Pan Zhang
Representing a grain structure within a combined finite element computer aided engineering environment is essential for micromechanics simulations. Methods are required to effectively generate high-fidelity virtual grain structures for accurate studies. A high-fidelity virtual grain structure means a statistically equivalent structure in conjunction with desired grain size distribution features, and must be represented with realistic grain morphology. A family of controlled Poisson Voronoi tessellation (CPVT) models have been developed in this work for systematically generating...

Development of a combined mathematical and experimental framework for the control and optimisation of mammalian cell culture systems

Alexandros-Dimitrios Kyparissidis
Even relatively simple microorganisms, which have been extensively studied, are hosts to a complex network of interconnected processes occurring on diverse time scales. The multilevel nature of the regulatory network of cells and the interactions occurring at the intra cellular level further augment this complexity (Yokobayashi et al., 2003). Attempts to wholly model the function of even a single cell are currently non trivial, if not impossible, as the amount of delicate intracellular measurements required...

Catalytic production of petrochemical products from bio-alcohols

Rashid Al-Hajri
Large-scale petrochemicals are typically produced using petroleum olefins as a feedstock. The desire to move toward a sustainable and environmentally friendly chemical industry has lead to interest in the use of bio-derived feedstocks such as alcohols which are currently being produced on an increasingly large scale by fermentation or from synthesis gas. The research investigated the direct catalytic production of ethylene, acetaldehyde, ethylene dichloride (EDC), and ethylene oxide (EO) from ethanol. Two approaches were considered:...

Studies towards elucidating the binding modes between metal-salphen complexes and G-quadruplex DNA

Nurul Huda Abd Karim
Studies on G-quadruplex DNA have grown rapidly due to the potential important roles this type of DNA may play in biology. Stabilisation of telomeric G-quadruplex DNA is thought to inhibit telomerase, an enzyme overexpressed in 85-90 % of cancerous cells. There are also evidences that formation of quadruplex DNA in the promoter region of certain oncogenes (e.g. c-MYC) can suppress their transcription. Therefore, targeting G-quadruplex DNA with small molecules could have interesting applications in cancer...

Process development for forging lightweight multi-material gears

Denis Politis
The work presented in this thesis discusses the development of an innovative method for manufacturing tailored gears, specifically bi-metallic lightweight gears through the use of the forging process. Utilising this method, gears can be constructed from multiple metals, where high strength, high density materials are located in regions of high stress concentration, such as the tooth flank, tooth root and regions in contact with shaft attachment mechanisms. On the other hand, lower strength, lower density...

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