Fabrication and application of short and novel structure in-fibre Bragg gratings

This thesis presents details on progress made in the fabrication and application of short and novel structure fibre Bragg gratings. The basic theoretical concepts of in-fibre Bragg gratings and photosensitive mechanisms are introduced together with an overview of fabrication methods and applications presented to date. The fabrication of fibre Bragg gratings using a quadrupled Nd:YAG laser is presented and some of the issues of grating fabrication using a fabrication using a phasemask are investigated, including the variation of the separation of the fibre and phasemask, and other alignment issues. A new apodisation technique is presented, enabling the production of gratings with a wide range of spectral profiles. The technique is used to investigate the design and fabrication of length limited fibre Bragg gratings for use in telecommunication systems as filters. Application to devices designed for use in WDM systems is presented. The use of fibre Bragg gratings as high spatial resolution distributed sensors is investigated. Grating sensing arrays comprising very short apodised gratings are demonstrated and Chirped Moiré gratings are implemented as distributed sensors achieving high spatial resolution with miniature point sensing sub-elements. A novel grating sensing element designed to imitate an interferometer is also presented. Finally, the behaviour of gratings fabricated in Boron-Germania-co-doped fibre is investigated, revealing atypical behaviour of the Bragg wavelength during ageing.

Outlook and application status of the Rolls-Royce Fuel Cell Systems SOFC

Rolls-Royce fuel cell systems is developing megawatt scale power systems based on solid oxide fuel cell technology. The hybrid design promises to meet challenging energy efficiency, cost and performance targets in a grid friendly fashion. Analysis and testing to date indicate that those targets can be met and enable a wealth of fuel cell applications to meet customer and existing grid and modern grid requirements. Working with a global development team, a series of laboratory tests and evaluations are completed and future field test and evaluation and demonstration planned.

Development and application of magnetoencephalographic methods in the investigation of the human visual system

This thesis is an exploration of the organisation and functioning of the human visual system using the non-invasive functional imaging modality magnetoencephalography (MEG). Chapters one and two provide an introduction to the ‘human visual system and magnetoencephalographic methodologies. These chapters subsequently describe the methods by which MEG can be used to measure neuronal activity from the visual cortex. Chapter three describes the development and implementation of novel analytical tools; including beamforming based analyses, spectrographic movies and an optimisation of group imaging methods. Chapter four focuses on the use of established and contemporary analytical tools in the investigation of visual function. This is initiated with an investigation of visually evoked and induced responses; covering visual evoked potentials (VEPs) and event related synchronisation/desynchronisation (ERS/ERD). Chapter five describes the employment of novel methods in the investigation of cortical contrast response and demonstrates distinct contrast response functions in striate and extra-striate regions of visual cortex. Chapter six use synthetic aperture magnetometry (SAM) to investigate the phenomena of visual cortical gamma oscillations in response to various visual stimuli; concluding that pattern is central to its generation and that it increases in amplitude linearly as a function of stimulus contrast, consistent with results from invasive electrode studies in the macaque monkey. Chapter seven describes the use of driven visual stimuli and tuned SAM methods in a pilot study of retinotopic mapping using MEG; finding that activity in the primary visual cortex can be distinguished in four quadrants and two eccentricities of the visual field. Chapter eight is a novel implementation of the SAM beamforming method in the investigation of a subject with migraine visual aura; the method reveals desynchronisation of the alpha and gamma frequency bands in occipital and temporal regions contralateral to observed visual abnormalities. The final chapter is a summary of main conclusions and suggested further work.

The synthesis and application of room temperature ionic liquids

This research project is concerned with the development and use of eco-friendly reaction media for a variety of organic transformations in the preparation of organic chemicals with potential pharmaceutical applications. These chemicals will then be investigated for their anti-cancer, anti-bacterial and anti-inflammation properties. In this project, different methods were used to synthesize various kinds of ionic liquids. Some new ionic liquids were prepared. In addition, Knoevenagel condensation reactions were investigated in RTILs. For the first time, some neutral ionic liquids such as [BMIM]+[BF4]-, [MeOEtMIM]+[CF3COO]- acted as both catalysts and solvents to promote Knoevenagel reactions. All these experiments indicated that RTILs have a great potential as alternative solvents in synthetic chemistry. Furthermore, nucleoside chemistry is an important research area in drug discovery. Various chemical modified nucleosides have therapeutic activities. However, these compounds usually have poor solubility in common organic solvents. RTILs such as [MeOEtMIM]+[CH3SO3]- have good dissolving capability for these chemicals. A range of thio-substituted nucleobases and nucleosides with potential pharmaceutical applications have been synthesized in several RTILs. These chemicals will then be investigated for their anti-cancer properties.

Isolation, characterisation and application of novel microbial protein cross-linking enzymes

Microbial transglutaminase is favoured for use in industry over the mammalian isoform, and hence has been utilized, to great effect, as an applied biocatalyst in many industrial areas including the food and textiles industries. There are currently only a limited number of microbial TGase sources known. A number of organisms have been screened for transglutaminase activity using biochemical assays directed towards TGase catalyzed reactions (amine incorporation and peptide cross-linking assay). Of those organisms screened, TGase was identified in a number of isolates including members of the Bacillus and Streptomyces families. In addition, a protein capable of performing a TGase-like reaction was identified in the organism Pseudomonas putida that was deemed immunologically distinct from previously described TGase isoforms, though further work would be required to purify the protein responsible. The genuses Streptoverticillium and Streptomyces are known to be closely related. A number of micro-organisms relating to Streptomyces mobaraensis (formerly Streptoverticillium mobaraensis) have been identified as harboring a TGase enzyme. The exact biological role of Streptomyces TGase is not well understood, though from work undertaken here it would appear to be involved in cell wall growth. Comparison of the purified Streptomyces TGase proteins showed them to exhibit marginally different characteristics in relation to enzymatic activity and pH dependency upon comparison with Streptomyces mobaraensis TGase. In addition, TGase was identified in the organism Saccharomonospora viridis that was found to be genetically identical to that from S. mobaraensis raising questions about the enzymes dissemination in nature. TGase from S. baldaccii was found to be most diverse with respect to enzymatic characteristics whilst still retaining comparable E(y-glutamyl) lysine bond formation to S. mobaraensis TGase. As such S. baldaccii TGase was cloned into an expression vector enabling mass production of the enzyme thereby providing a viable alternative to S. mobaraensis TGase for many industrial processes.

The development and application of an interactive material requirements planning model

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The development and application of a coding and classification system for manufacturing industry

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

Breakage model development and application with CFD for predicting breakage of whey protein precipitate particles

Particle breakage due to fluid flow through various geometries can have a major influence on the performance of particle/fluid processes and on the product quality characteristics of particle/fluid products. In this study, whey protein precipitate dispersions were used as a case study to investigate the effect of flow intensity and exposure time on the breakage of these precipitate particles. Computational fluid dynamic (CFD) simulations were performed to evaluate the turbulent eddy dissipation rate (TED) and associated exposure time along various flow geometries. The focus of this work is on the predictive modelling of particle breakage in particle/fluid systems. A number of breakage models were developed to relate TED and exposure time to particle breakage. The suitability of these breakage models was evaluated for their ability to predict the experimentally determined breakage of the whey protein precipitate particles. A "power-law threshold" breakage model was found to provide a satisfactory capability for predicting the breakage of the whey protein precipitate particles. The whey protein precipitate dispersions were propelled through a number of different geometries such as bends, tees and elbows, and the model accurately predicted the mean particle size attained after flow through these geometries. © 2005 Elsevier Ltd. All rights reserved.

Covalent attachment of chiral manganese(III) salen complexes onto functionalised hexagonal mesoporous silica and application to the asymmetric epoxidation of alkenes

Two modified Jacobsen-type catalysts were anchored onto an amine functionalised hexagonal mesoporous silica (HMS) using two distinct anchoring procedures: (i) one was anchored directly through the carboxylic acid functionalised diimine bridge fragment of the complex (CAT1) and (ii) the other through the hydroxyl group on the aldehyde fragment of the complex (CAT2), mediated by cyanuric chloride. The new heterogeneous catalyst, as well as the precedent materials, were characterised by elemental analyses, DRIFT, UV-vis, porosimetry and XPS which showed that the complexes were successfully anchored onto the hexagonal mesoporous silica. These materials acted as active heterogeneous catalysts in the epoxidation of styrene, using m-CPBA as oxidant, and α-methylstyrene, using NaOCl as oxidant. Under the latter conditions they acted also as enantioselective heterogeneous catalysts. Furthermore, when compared to the reaction run in homogeneous phase under similar experimental conditions, an increase in asymmetric induction was observed for the heterogenised CAT1, while the opposite effect was observed for the heterogenised CAT2, despite of CAT2 being more enantioselective than CAT1 in homogeneous phase. These results indicate that the covalent attachment of the Jacobsen catalyst through the diimine bridge leads to improved enantiomeric excess (%ee), whereas covalent attachment through one of the aldehyde fragments results in a negative effect in the %ee. Using α-methylstyrene and NaOCl as oxidant, heterogeneous catalyst reuse led to no significant loss of catalytic activity and enantioselectivity. © 2005 Elsevier Inc. All rights reserved.

Fiber grating type dependence of temperature and strain coefficients and application to simultaneous temperature and strain measurement

Although fiber Bragg gratings (FBGs) have been widely used as advanced optical sensors, the cross-sensitivity between temperature and strain has complicated independent measurement procedures for these two measurands. We report here, for the first time to our knowledge, the results of a systematic investigation of the dependence of both temperature and strain sensitivities on the grating type, including the well-known Type I, Type IIA, and a new type which we have designated Type IA, using both hydrogen-free and hydrogenated B/Ge codoped fibers. We have identified distinct sensitivity characteristics for each grating type, and we have utilised them to implement a novel dual-grating, dual-parameter sensor device with performance superior to that of previously reported grating-based structures.

Verification and Application of Conceptual Model and Security Requirements on Practical DRM Systems in E-Learning

The paper represents a verification of a previously developed conceptual model of security related processes in DRM implementation. The applicability of established security requirements in practice is checked as well by comparing these requirements to four real DRM implementations (Microsoft Media DRM, Apple's iTunes, SunnComm Technologies’s MediaMax DRM and First4Internet’s XCP DRM). The exploited weaknesses of these systems resulting from the violation of specific security requirements are explained and the possibilities to avoid the attacks by implementing the requirements in designing step are discussed.

The Experience of Development and Application Perspectives of Learning Integrated Expert Systems in the Educational Process

The main principles and experience of development of learning integrated expert systems based on the third generation instrumental complex AT-TECHNOLOGY are considered.

Some historical extracts relevant to the discovery and application of the diffraction of X-rays by crystals to contribute to the centennial celebration and the International Year of Crystallography

Illustrative extracts from the writings of Paul P. Ewald and of Max von Laue are presented. The latter in turn contains extensive text contributions from William Lawrence Bragg. These selections we have chosen so as to indicate the nature of the discovery of X-ray diffraction from crystals (experiments undertaken by Friedrich, Knipping and von Laue) and its early and prompt application in crystal structure analyses (by William Henry Bragg and William Lawrence Bragg). The platform for these discoveries was provided by a macroscopic physics problem dealt with by Ewald in his doctoral thesis with Arnold Sommerfeld in the Munich Physics Department, which is also where von Laue was based. W.L. Bragg was a student in Cambridge who used Trinity College Cambridge as his address on his early papers; experimental work was done by him in the Cavendish Laboratory, Cambridge, and also with his father, W.H. Bragg, in the Leeds University Physics Department. Of further historical interest is the award of an Honorary DSc (Doctor of Science) degree in 1936 to Max von Laue by the University of Manchester, UK, while William Lawrence Bragg was Langworthy Professor of Physics there. © 2012 Copyright Taylor and Francis Group, LLC.