Small angle scattering characterisation of micellar systems and templated architectures

The work described in this thesis reports the structural changes induced on micelles under a variety of conditions. The micelles of a liquid crystal film and dilute solutions of micelles were subjected to high pressure CO2 and selected hydrocarbon environments. Using small angle neutron scattering (SANS) techniques the spacing between liquid crystal micelles was measured in-situ. The liquid crystals studied were templated from different surfactants with varying structural characteristics. Micelles of a dilute surfactant solution were also subjected to elevated pressures of varying gas atmospheres. Detailed modelling of the in-situ SANS experiments revealed information of the size and shape of the micelles at a number of different pressures. Also reported in this thesis is the characterisation of mesoporous materials in the confined channels of larger porous materials. Periodic mesoporous organosilicas (PMOs) were synthesised within the channels of anodic alumina membranes (AAM) under different conditions, including drying rates and precursor concentrations. In-situ small angle x-ray scattering (SAXS) and transmission electron microscopy (TEM) was used to determine the pore morphology of the PMO within the AAM channels. PMO materials were also used as templates in the deposition of gold nanoparticles and subsequently used in the synthesis of germanium nanostructures. Polymer thin films were also employed as templates for the directed deposition of gold nanoparticles which were again used as seeds for the production of germanium nanostructures. A supercritical CO2 (sc-CO2) technique was successfully used during the production of the germanium nanostructures.

Financial modelling with 2-EPT probability density functions

The class of all Exponential-Polynomial-Trigonometric (EPT) functions is classical and equal to the Euler-d’Alembert class of solutions of linear differential equations with constant coefficients. The class of non-negative EPT functions defined on [0;1) was discussed in Hanzon and Holland (2010) of which EPT probability density functions are an important subclass. EPT functions can be represented as ceAxb, where A is a square matrix, b a column vector and c a row vector where the triple (A; b; c) is the minimal realization of the EPT function. The minimal triple is only unique up to a basis transformation. Here the class of 2-EPT probability density functions on R is defined and shown to be closed under a variety of operations. The class is also generalised to include mixtures with the pointmass at zero. This class coincides with the class of probability density functions with rational characteristic functions. It is illustrated that the Variance Gamma density is a 2-EPT density under a parameter restriction. A discrete 2-EPT process is a process which has stochastically independent 2-EPT random variables as increments. It is shown that the distribution of the minimum and maximum of such a process is an EPT density mixed with a pointmass at zero. The Laplace Transform of these distributions correspond to the discrete time Wiener-Hopf factors of the discrete time 2-EPT process. A distribution of daily log-returns, observed over the period 1931-2011 from a prominent US index, is approximated with a 2-EPT density function. Without the non-negativity condition, it is illustrated how this problem is transformed into a discrete time rational approximation problem. The rational approximation software RARL2 is used to carry out this approximation. The non-negativity constraint is then imposed via a convex optimisation procedure after the unconstrained approximation. Sufficient and necessary conditions are derived to characterise infinitely divisible EPT and 2-EPT functions. Infinitely divisible 2-EPT density functions generate 2-EPT Lévy processes. An assets log returns can be modelled as a 2-EPT Lévy process. Closed form pricing formulae are then derived for European Options with specific times to maturity. Formulae for discretely monitored Lookback Options and 2-Period Bermudan Options are also provided. Certain Greeks, including Delta and Gamma, of these options are also computed analytically. MATLAB scripts are provided for calculations involving 2-EPT functions. Numerical option pricing examples illustrate the effectiveness of the 2-EPT approach to financial modelling.

Between the worlds: otherworld women as intermediaries in early Irish literature

This thesis examines the ways in which Otherworldly women acted as intermediaries between the Otherworld and mortal world in early Irish literature. First it establishes the position of women in early Ireland so that appropriate comparisons can be made between mortal and Otherworld women throughout the thesis. Also, it defines what is meant by the ‘Otherworld’ and its relevence to the early Irish. It then goes on to discuss the differing goals of various intermediaries in early Irish texts, and in what manner they interact with mortals. It briefly looks at how Otherworld male intermediaries are treated differently in the literature, and why early authors might have used women in these roles as often as they did.

Medieval Irish vision literature: a genre study

This dissertation examines medieval literary accounts of visions of the afterlife with an origin or provenance in Ireland from the perspective of genre, analysing their structural and literary characteristics both synchronically and diachronically. To this end, I have developed a new typology of medieval vision literature. I address the question in what manner the internationally attested genre of vision literature is adapted and developed in an Irish literary milieu. I explore this central research question through an interrogation of the typological unity of the key texts, both in formal arrangement and in the eschatological themes they express. My analysis of the structure and rhetoric of these narratives reveals the primary role of identity strategies, question-and-answer patterns and exhortation for their narrative cohesion and didactic function. In addition, I was able to make a formal distinction at text-level between the adaptation of the genre as an autonomous unit and the adaptation of thematic motifs as topoi. This further enabled me to nuance the distribution of characteristic features in the genre. My analysis of the spatial and temporal aspects of the eschatological journey confirms a preoccupation with personal eschatology. It reveals a close connection between the development of the aspects of graded access and trial in the genre and a growing awareness of an interim state of the soul after death. Finally, my dissertation provides new editions, translations and analyses of primary sources. My research breaks new ground in the hitherto underexplored area of genre adaptation in Ireland. In addition, it contributes significantly to our understanding of the nature of vision literature both in an Irish and a European context, and to our knowledge of the transmission of eschatological thought in the Latin West. Discusses the visions of: Laisrén, Fursa, Adomnán, Lóchán, Tnugdal, Owein and Visio Sancti Pauli Redactions VI and XI.

Synthesis, characterisation and applications of group IV nanocrystals

Group IV materials such as silicon nanocrystals (Si NCs) and carbon quantum dots (CQDs) have received great attention as new functional materials with unique physical/chemical properties that are not found in the bulk material. This thesis reports the synthesis and characterisation of both types of nanocrystal and their application as fluorescence probes for the detection of metal ions. In chapter 2, a simple method is described for the size controlled synthesis of Si NCs within inverse micelles having well defined core diameters ranging from 2 to 6 nm using inert atmospheric synthetic methods. In addition, ligands with different molecular structures were utilised to reduce inter-nanocrystal attraction forces and improve the stability of the NC dispersions in water and a variety of organic solvents. Regulation of the Si NCs size is achieved by variation of the surfactants and addition rates, resulting high quality NCs with standard deviations (σ = Δd/d) of less than 10 %. Large scale production of highly mondisperse Si NC was also successfully demonstrated. In chapter 3, a simple solution phase synthesis of size monodisperse carbon quantum dots (CQDs) using a room temperature microemulsion strategy is demonstrated. The CQDs are synthesized in reverse micelles via the reduction of carbon tetrachloride using a hydride reducing agent. CQDs may be functionalised with covalently attached alkyl or amine monolayers, rendering the CQDs dispersible in wide range of polar or non-polar solvents. Regulation of the CQDs size was achieved by utilizing hydride reducing agents of different strengths. The CQDs possess a high photoluminescence quantum yield in the visible region and exhibit excellent photostability. In chapter 4, a simple and rapid assay for detection of Fe3+ ions was developed, based on quenching of the strong blue-green Si NC photoluminescence. The detection method showed a high selectivity, with only Fe3+ resulting in strong quenching of the fluorescence signal. No quenching of the fluorescence signal was induced by Fe2+ ions, allowing for solution phase discrimination between the same ion in different charge states. The optimised sensor system showed a sensitive detection range from 25- 900 μM and a limit of detection of 20.8 μM

Narratives in early Irish law tracts

This thesis presents a study of the 112 narratives collected from the Corpus Iuris Hibernici. The selection of narratives is based on criteria informed by modern narratological theories. The significant presence of narratives in early Irish law tracts appears at odds with the normal conception of law texts as consisting solely of provisions, and therefore needs to be accounted for. Since no systematic study has been conducted of these legal narratives, this thesis serves as an introduction by giving firstly an index of narratives and secondly a categorisation of them in terms of distribution, dates and functions. It then carries out a general analysis of the relationship between legal narratives and early Irish literature, and a selected case study of the relationship between legal narratives and the legal institutions in the context of which the narratives are located. It has become clearer, with the progress of argument, that the use of narratives was an integral part of legal writing in medieval Ireland; and the narratives, though having many idiosyncratic features of themselves, are profoundly connected with the learned tradition at large. The legal narratives reveal the intellectual background and compositional concerns of medieval Irish jurists, and they formed a crucial part of the effort to accommodate law tracts into the dynamic tradition of senchas. Two appendices are included at the end: one consists of translations of 34 narratives from the index, and the other is a critical edition of one of the narratives discussed in detail, together with translations of some relevant passages.

Synthesis, functionalisation and characterisation of germanium nanocrystals & their applications

In the last two decades, semiconductor nanocrystals have been the focus of intense research due to their size dependant optical and electrical properties. Much is now known about how to control their size, shape, composition and surface chemistry, allowing fine control of their photophysical and electronic properties. However, genuine concerns have been raised regarding the heavy metal content of these materials, which is toxic even at relatively low concentrations and may limit their wide scale use. These concerns have driven the development of heavy metal free alternatives. In recent years, germanium nanocrystals (Ge NCs) have emerged as environmentally friendlier alternatives to II-VI and IV-VI semiconductor materials as they are nontoxic, biocompatible and electrochemically stable. This thesis reports the synthesis and characterisation of Ge NCs and their application as fluorescence probes for the detection of metal ions. A room-temperature method for the synthesis of size monodisperse Ge NCs within inverse micelles is reported, with well-defined core diameters that may be tuned from 3.5 to 4.5 nm. The Ge NCs are chemically passivated with amine ligands, minimising surface oxidation while rendering the NCs dispersible in a range of polar solvents. Regulation of the Ge NCs size is achieved by variation of the ammonium salts used to form the micelles. A maximum quantum yield of 20% is shown for the nanocrystals, and a transition from primarily blue to green emission is observed as the NC diameter increases from 3.5 to 4.5 nm. A polydisperse sample with a mixed emission profile is prepared and separated by centrifugation into individual sized NCs which each showed blue and green emission only, with total suppression of other emission colours. A new, efficient one step synthesis of Ge NCs with in situ passivation and straightforward purification steps is also reported. Ge NCs are formed by co-reduction of a mixture of GeCl4 and n-butyltrichlorogermane; the latter is used both as a capping ligand and a germanium source. The surface-bound layer of butyl chains both chemically passivates and stabilises the Ge NCs. Optical spectroscopy confirmed that these NCs are in the strong quantum confinement regime, with significant involvement of surface species in exciton recombination processes. The PL QY is determined to be 37 %, one of the highest values reported for organically terminated Ge NCs. A synthetic method is developed to produce size monodisperse Ge NCs with modified surface chemistries bearing carboxylic acid, acetate, amine and epoxy functional groups. The effect of these different surface terminations on the optical properties of the NCs is also studied. Comparison of the emission properties of these Ge NCs showed that the wavelength position of the PL maxima could be moved from the UV to the blue/green by choice of the appropriate surface group. We also report the application of water-soluble Ge NCs as a fluorescent sensing platform for the fast, highly selective and sensitive detection of Fe3+ ions. The luminescence quenching mechanism is confirmed by lifetime and absorbance spectroscopies, while the applicability of this assay for detection of Fe3+ in real water samples is investigated and found to satisfy the US Environmental Protection Agency requirements for Fe3+ levels in drinkable water supplies.

The Celtic dragon slayer - a literary analysis of Tochmarc Emire in connection with Tristan et Iseut

As Celtic scholars have long noted, the medieval Irish tale Tochmarc Emire “The Courtship of Emer” is heavily indebted to other medieval Irish texts. In this tale of courtship and otherworldly quests, the Irish hero Cú Chulainn must prove himself worthy of the hand of the noblewoman Emer. Among his overseas adventures, Cú Chulainn rescues a princess from three attackers of the Fomoire. This episode may represent the only medieval Irish example of AT300 “The Dragon Slayer”, a story pattern known from classical models such as the stories of Perseus and Andromeda; and Hercules and Hesione. Moreover, in the company of Cú Chulainn we find a character otherwise unknown to Irish tradition by the name of Drust mac Seirb. This has led scholars to argue that Tochmarc Emire may preserve a Celtic precursor of the Continental Tristan legend, seeing in Drust the Pictish origin of the character Tristan, himself a famous dragon slayer. In this interdisciplinary dissertation, a number of questions are addressed. If the redactor of Tochmarc Emire drew on material from outside Irish tradition, what does this tell us about medieval Irish concepts of literature and genre? Further, what evidence do we have for tracing the origin of the Continental Tristan legend back to Pictland, and what explanation might we offer for a putative Pictish prince featuring in an Irish Dragon Slayer story? Finally, what place does the Dragon Slayer episode occupy within Tochmarc Emire and can we find other narratives, Celtic or classical or other, fitting the pattern of AT300, which may strengthen the link between Tochmarc Emire and Tristan?

Designing and evaluating an interactive assessment instrument to improve the process for mobile service application innovation

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