<p>In this thesis, regioregularpoly( 3-hexylthiophene) (rr-P3HT) polymer was used as a light absorption and electron donating material, while the C60 fullerene and its derivative [6,6]-phenyl C61-butyric acid methyl ester (PCBM) were used as electron acceptor materials. The effect of solvent to control the degree of mixing of the polymer and fullerene components, as well as the domain size and charge transport properties of the blends were investigated in detail using P3HT:C60 films. The photo-physical, structural and electrical transport properties of the polymer blends were carried out according to their ratios. A distinctive photoluminescence (PL) quenching effect was observed indicating a photo-induced electron transfer. In this thesis, the effect of solvents on the crystallization and interchain interaction of P3HT and C60 fullerene films were studied using XRD, UV-vis, PL, Raman and FTIR spectroscopy. The polymer blends formed with non-aromatic solvents exhibited an improved crystallinity and polymer morphology than that formed with aromatic solvents. An improved ordering was demonstrated in the polymer films spin coated from non-aromatic solvents. This indicates that the limited solubility of rr P3HT in a marginal solvent such as non-aromatic solvents can offer a strategy to obtain highly ordered crystal structures and lead directly to optimal morphologies on the films.</p>

<p>Antimicrobial peptides (AMPs) play a key role in the innate immune response. They can be ubiquitously found in a wide range of eukaryotes including mammals, amphibians, insects, plants, and protozoa. In lower organisms, AMPs function merely as antibiotics by permeabilizing cell membranes and lysing invading microbes. Prediction of antimicrobial peptides is important because experimental methods used in characterizing AMPs are costly, time consuming and resource intensive and identification of AMPs in insects can serve as a template for the design of novel antibiotic. In order to fulfil this, firstly, data on antimicrobial peptides is extracted from UniProt, manually curated and stored into a centralized database called dragon antimicrobial peptide database (DAMPD). Secondly, based on the curated data, models to predict antimicrobial peptides are created using support vector machine with optimized hyperparameters. In particular, global optimization methods such as grid search, pattern search and derivative-free methods are utilised to optimize the SVM hyperparameters. These models are useful in characterizing unknown antimicrobial peptides. Finally, a webserver is created that will be used to predict antimicrobial peptides in haemotophagous insects such as Glossina morsitan and Anopheles gambiae.</p>

It is well known that texture and microstructure play a crucial role in determining properties of metallic materials. The evolution of microstructure and texture during deformation and annealing of copper and some copper base alloys have been investigated to some extent. However, the knowledge about the role of the mode of deformation, particularly different variants of rolling deformation, is still very limited for deformation and annealing texture of two-phase copper alloys. Therefore it appeared important to study the influence of deformation path (in the present case, mode of rolling) on texture and microstructure in two-phase copper alloy Cu-40Zn alloy. Hot rolled bar of Cu-40Zn alloy (as-received material) was subjected to unidirectional and cross rolling ( multi-step cross-rolling) at room temperature with strain per pass (true strain) being constant for each step. In multi-step cross-rolling, the rolling direction was altered (rotated by 90°)after each pass. Strains corresponding to rolling reduction of 50% and 80% were given to as-received material through each of the different mode of rolling. In a second route, the as-received material was solution treated at 800°C for 4 hours first and then subjected to rolling in the same manner as above. A piece was cut from each of the as-rolled materials and was subjected to annealing at 560°C for one hour for recrystallization. The bulk textures were determined by measuring the pole figures at the center of the rolled as well as the annealed specimen using X-ray texture goniometer based on Schultz reflection geometry. Three dimensional texture analyses were carried out using the method of orientation distribution function(ODF). Micro-textures and associated microstructural parameters were determined using a Field Emission Gun Scanning Electron Microscope(FEG-SEM) operated at 20KV, equipped with Electron back scattering detector(EBSD). In the experimental material, texture was examined for both the α (fcc) and the β (ordered cubic) phases. In the present investigation, α phase of unidirectional rolled as-received material had Bs {011}<112> orientation as the strongest component whereas for multi-step cross rolled material P(BND) {011}<111> orientation had the maximum intensity, which could be obtained by rotating the Bs orientation and about ND.The texture development of β phase of as-received unidirectional rolled sample could be understood in terms of relaxed constraints Taylor model. The initial texture had a pronounced effect on texture development of α phase for solution treated alloy during deformation. This material exhibited very strong P(BND) {011}<111> orientation for unidirectional as well as for multi-step cross rolling. For cross rolled alloys, this orientation is promoted by two factors simultaneously, (i) initial texture and (ii) special attributes of cross rolling process. The volume fraction of cube oriented grains was very low for all recrystallized samples because of dominance of Bs orientation in the deformation texture plus formation of shear bands in the microstructure. The texture of β phase for unidirectionally rolled solution treated alloy got sharpened on annealing. However, strength of texture decreased with increasing deformation. Grain boundary (and CSL boundary) analyses were carried out with EBSD data. These analyses indicated that all the recrystallized samples had a high number of Σ3 boundaries. The proportion of Σ3 boundaries was higher in multi-step cross-rolled annealed material. The deformed material had higher number fraction of low angle boundary than any other special boundary. Solution treated material had an average grain size of α phase smaller than the as-received material. Another dimension of the present investigation was to characterize the microstructural features in three dimension(3D) in order to examine the morhphology of constituent phases using serial sectioning. In the present work, 3D studies were carried out on the alloy after post deformation annealing. The alignment of serial section images and generation of 3D image out of the stack of 2D images was carried out through standard software. The same was used to measure the suitable 3D microstructural parameters from the 2D sections. Three dimensional microstructural parameters like mean caliper diameter of β particle, number of β particles per unit volume ‘Nv’, surface to volume ratio for β phase particles (α- β interface) ‘Sv’, were calculated. Number of β particle intercepts per unit area ‘NA’ was determined by measuring number of β phase particle in each section. The volume of a β particle as calculated from the caliper diameter using three-dimensional microstructural analysis, which could not get directly determined with conventional two-dimensional microscopy.

The p-median problem is often used to locate p service centers by minimizing their distances to a geographically distributed demand (n). The optimal locations are sensitive to geographical context such as road network and demand points especially when they are asymmetrically distributed in the plane. Most studies focus on evaluating performances of the p-median model when p and n vary. To our knowledge this is not a very well-studied problem when the road network is alternated especially when it is applied in a real world context. The aim in this study is to analyze how the optimal location solutions vary, using the p-median model, when the density in the road network is alternated. The investigation is conducted by the means of a case study in a region in Sweden with an asymmetrically distributed population (15,000 weighted demand points), Dalecarlia. To locate 5 to 50 service centers we use the national transport administrations official road network (NVDB). The road network consists of 1.5 million nodes. To find the optimal location we start with 500 candidate nodes in the network and increase the number of candidate nodes in steps up to 67,000. To find the optimal solution we use a simulated annealing algorithm with adaptive tuning of the temperature. The results show that there is a limited improvement in the optimal solutions when nodes in the road network increase and p is low. When p is high the improvements are larger. The results also show that choice of the best network depends on p. The larger p the larger density of the network is needed.

The improvement in mechanical strength offered by ultra fine- (UF) and nanocrystalline (NC) sized grains is very attractive for potential applications of structural metals. Accumulative Roll-Bonding (ARB) is one of the promising new techniques for producing bulk UF grained metals. There are numerous reports on the monotonic mechanical behavior of various ARBed metals, however there are few, if any, on the cyclic deformation behavior of such metals. The primary objective of this study is to investigate the cyclic deformation behaviour and the related micro-mechanisms of ARBed metals from a fundamental perspective. To achieve this, the microstructure and the deformation behavior of commercial purity aluminum, OFHC copper, and DLP copper after ARB processing have been systematically characterized. The as-ARBed microstructure is found to be composite natured, with constituents of different grain sizes. The three constituents are: (i)UF grained matrix, (ii)NC primary discontinuities, and (iii)conventional sized pre-existing coarse grains. Due to this composite nature, three different cyclic strain accommodation mechanisms were found in the ARBed OFHC copper: (i)conventional dislocation patterns in the large grains, (ii)reactivation of pre-existing shear bands, and (iii)stress/strain driven grain coarsening at sites of strain localization. The order of activation of the mechanisms can be described with a composite approach based on activation energy. The occurrence of grain coarsening is the major contributor to the cyclic softening response observed in OFHC copper. Conversely, the lesser extent of cyclic softening in the other two metals is likely due to the higher microstructure stability of the initial as-ARBed materials. The microstructure stability is believed to be the primary influencing factor for the extent of grain coarsening and cyclic softening. The applied cyclic plastic strain is a secondary influencing factor, although this is generally overshadowed by the limitation of grain coarsening due to the short cyclic lifespan of these metals. The occurrences of shear banding and grain coarsening reported in the present ARBed metals are similarly reported for UF grained metals from other processes, e.g. ECAPed metals. Thus, its relationship to the cyclic deformation response and governing factors are believed to be applicable for UF grained metals in general.

The improvement in mechanical strength offered by ultra fine- (UF) and nanocrystalline (NC) sized grains is very attractive for potential applications of structural metals. Accumulative Roll-Bonding (ARB) is one of the promising new techniques for producing bulk UF grained metals. There are numerous reports on the monotonic mechanical behavior of various ARBed metals, however there are few, if any, on the cyclic deformation behavior of such metals. The primary objective of this study is to investigate the cyclic deformation behaviour and the related micro-mechanisms of ARBed metals from a fundamental perspective. To achieve this, the microstructure and the deformation behavior of commercial purity aluminum, OFHC copper, and DLP copper after ARB processing have been systematically characterized. The as-ARBed microstructure is found to be composite natured, with constituents of different grain sizes. The three constituents are: (i)UF grained matrix, (ii)NC primary discontinuities, and (iii)conventional sized pre-existing coarse grains. Due to this composite nature, three different cyclic strain accommodation mechanisms were found in the ARBed OFHC copper: (i)conventional dislocation patterns in the large grains, (ii)reactivation of pre-existing shear bands, and (iii)stress/strain driven grain coarsening at sites of strain localization. The order of activation of the mechanisms can be described with a composite approach based on activation energy. The occurrence of grain coarsening is the major contributor to the cyclic softening response observed in OFHC copper. Conversely, the lesser extent of cyclic softening in the other two metals is likely due to the higher microstructure stability of the initial as-ARBed materials. The microstructure stability is believed to be the primary influencing factor for the extent of grain coarsening and cyclic softening. The applied cyclic plastic strain is a secondary influencing factor, although this is generally overshadowed by the limitation of grain coarsening due to the short cyclic lifespan of these metals. The occurrences of shear banding and grain coarsening reported in the present ARBed metals are similarly reported for UF grained metals from other processes, e.g. ECAPed metals. Thus, its relationship to the cyclic deformation response and governing factors are believed to be applicable for UF grained metals in general.

Wastewater treatment and re-use of industrial process water is a critical issue for the suitable development of human activities. The need for effective water recycling has reinforced the research on tailored low cost pollution abatement since the existing solutions are not longer universal. In particular, the emerging Catalytic Wet Air Oxidation (CWAO) process is one of the most promising technologies for the remediation of moderately concentrated and/or biotoxic water pollutants, when a stable and active catalyst can be provided. To this purpose, the catalytic activity and stability of active carbon was tested in the CWAO of the target compound, phenol, at mild conditions of temperature and pressure. The active carbon, which is a relatively inexpensive catalytic material is shown to be stable and to yield higher phenol destruction and less toxic partial mineralisation products, compared to a widely used copper oxide catalyst. During the CWAO of phenol, numerous partial oxidation products appeared and the knowledge of the kinetics that control their oxidation process is fundamental for the design, modelling and scale up of CWAO pilot plant or industrial units. Complex kinetic modelling was undertaken using both the classical gradient based method and a stochastic algorithm termed Simulated Annealing (SA). SA was shown to perform better in the identification of multiparameter kinetic reaction schemes, allowing to improve the kinetic modelling of CWAO beyond the actual state of art in this field. Detailed kinetic analysis of CWAO is scarce in the literature and the same situation holds for engineering studies. There is a clear need for the simultaneous development of process chemistry and engineering aspects. Consequently, we parallely focused on the state of art modelling of a Trickle Bed Reactor (TBR), being the priority candidate of best performing CWAO reactor. First, the ability of TBR in CWAO was affirmed by appropriate experimental comparison of batch slurry reactor and continuous fixed bed reactors operating either in the cocurrent downflow mode (TBR), or upflow mode (FBR) of the gas and liquid flow. A phenomenological transport-reaction model of the TBR was then developed and programmed. The TBR model implements the previously obtained oxidation kinetics and emphasis on important aspects of TBR, namely catalyst wetting, and mass transfer between the phases. Non-isothermal operation is also accounted for to face the need for autothermal operation, lowering the global process costs. The validation of the model was successfully done with the available experimental data from the laboratory TBR and thus provided a reliable tool for the scale up study of the CWAO process. The outcomings of this model aided scale up, allow to give recommendation on the design and operation of industrial units, thereby making more reliable the implementation of CWAO units on an industrial level. / El tratamiento y el reciclaje de afluentes acuosos son de máximo interés para conseguir un desarrollo sostenible de las actividades humanas. La necesidad de aprovechar en un futuro cercano las aguas residuales de procesos industriales de un modo eficaz ha reforzado la investigación sobre métodos de bajo coste para su recuperación, dado que las tecnologías existentes ya no son universalmente aplicables. La oxidación catalítica por vía húmeda (CWAO) es uno de los procesos emergentes más prometedores particularmente para el tratamiento de aguas contaminadas con materia orgánica, en concentraciones medio altas, y/o biotóxica. Sin embargo, la implementación del método es adecuada siempre que se use un catalizador activo y estable. Con este propósito, la actividad catalítica y la estabilidad del carbón activo se ha comprobado en la CWAO usando como compuesto modelo el fenol. En condiciones de temperatura y presión moderadas el carbón activo ha demostrado ser un material catalítico barato, que a la vez, es estable, mas activo en la conversión de fenol, además produciendo menor cantidad de productos de oxidación parcial tóxicos que los catalizadores soportados convencionales. Durante la CWAO del fenol, numerosos productos intermedios se forman, por lo que el conocimiento de la cinética de su oxidación es fundamental para el diseño, modelización y escalado fiable del proceso a escala de planta piloto o incluso industrial. Debido a la insuficiencia de los clásicos métodos de optimización para llevar acabo la estimación de parámetros en modelos de alta complejidad, el uso de algoritmos estocásticos se ha probado con éxito, permitiendo el desarrollo de modelos cinéticos más avanzados que los que se implementan actualmente en el campo de la CWAO. El desarrollo de modelos cinéticos complejos es escaso en la literatura actual, así como los estudios que tratan los aspectos químicos y de ingeniería del proceso de la CWAO. Sin embargo, hay una necesidad clara para el desarrollo simultaneo de los aspectos químicos y de ingeniería de la tecnología. Consecuentemente, en paralelo se ha enfocado en la modelización de un reactor de goteo (TBR), según el estado de arte actual en el campo de estos reactores. Es demostrado que estos reactores son más adecuados que los reactores agitados con catalizador en suspención para la CWAO de compuestos orgánicos que tienden a reacciones de polimerización en fase liquida. Además se han probado dos distintos modos de operación, con flujo de gas y liquido cocorriente descendiente o ascendiente, y se ha demostrado que la primera forma de operación es la mas adecuada para este sistema. A continuación un modelo fenomenológico para el TBR ha sido desarrollado y programado. El modelo implementa la cinética previamente obtenida, y además se ha puesto énfasis en la incorporación de los efectos de mojado, y de transferencia de materia. La operación no isotérmica se ha estudiado también para investigar la posibilidad de operar de modo autotérmico, disminuyendo así los costes de operación del proceso. La validación del modelo fenomenológico con los datos experimentales obtenidos en el TBR del laboratorio ha sido favorable. Posteriormente, este modelo ha sido utilizado como una herramienta fiable para el escalado del proceso. Los resultados obtenidos de la modelización del escalado permiten la extracción de recomendaciones sobre el diseño y la operación de unidades industriales, haciendo más fiable la aplicación del método a escala industrial.

<p>Hydrogenated amorphous silicon (a-Si:H) is second only to crystalline silicon in volume manufacturing of solar cells due to its attractive characteristics for solar panel manufacturing. These are lower manufacturing costs, and the fact that it can be deposited on any surface, and in any shape even on flexible substrates. The metal induced crystallization of hydrogenated amorphous silicon has been the subject of intense scrutiny in recent years. By combining the technology of hydrogenated amorphous silicon thin films with the superior characteristics of c-Si material, it is hoped that more efficient solar cells can be produced. In this thesis we report on the metal-mediated-thermally induced changes of the structural and optical properties of hydrogenated amorphous silicon deposited by hot-wire CVD, where aluminium and nickel were used to induce crystallization. The metal-coated amorphous silicon was subjected to a thermal annealing regime of between 150 and 520&deg / C. The structural measurements, obtained by Raman spectroscopy, show partial crystallization occurring at 350 &deg / C. At the higher annealing temperatures of 450&deg / C and 520&deg / C complete crystallization occurs. Reflection and transmission measurements in the UV-visible range were then used to extract the optical properties. By adopting the effective medium approximation a single optical model could be constructed that couldsuccessfully model material that was in different structural phases, irrespective of metal contamination. Changes in the absorption of the material in various stages of transition were confirmed with a directly measured absorption technique, and the modelled absorption closely followed the same trends This study forms part of the larger overall solar cell research project, of which the primary aim is to eventually develop a silicon solar panel that optimises the characteristics for best performance.</p>

The field of modelling and processing of 'images' has fairly recently become important, even crucial, to areas of science, medicine, and engineering. The inevitable explosion of imaging modalities and approaches stemming from this fact has become a rich source of mathematical applications. <br /><br /> 'Imaging' is quite broad, and suffers somewhat from this broadness. The general question of 'what is an image?' or perhaps 'what is a natural image?' turns out to be difficult to address. To make real headway one may need to strongly constrain the class of images being considered, as will be done in part of this thesis. On the other hand there are general principles that can guide research in many areas. One such principle considered is the assertion that (classes of) images have multiscale relationships, whether at a pixel level, between features, or other variants. There are both practical (in terms of computational complexity) and more philosophical reasons (mimicking the human visual system, for example) that suggest looking at such methods. Looking at scaling relationships may also have the advantage of opening a problem up to many mathematical tools. <br /><br /> This thesis will detail two investigations into multiscale relationships, in quite different areas. One will involve Iterated Function Systems (IFS), and the other a stochastic approach to reconstruction of binary images (binary phase descriptions of porous media). The use of IFS in this context, which has often been called 'fractal image coding', has been primarily viewed as an image compression technique. We will re-visit this approach, proposing it as a more general tool. Some study of the implications of that idea will be presented, along with applications inferred by the results. In the area of reconstruction of binary porous media, a novel, multiscale, hierarchical annealing approach is proposed and investigated.

Using block copolymers for large-area periodic structure fabrication is of great interest because of the potential for low fabrication costs and simplicity of the processing. The concept is that by selective inclusion of the nanoparticles into one of the blocks of a self-assembling copolymer, the nanoparticles are forced into a defined spatial arrangement determined by the phase morphology of the copolymer. Although copolymers can form well defined structures, they inherently have a 'polycrystalline' structure in the bulk, meaning that there is no long-range order of the domains. This thesis addresses both the effect of inclusion of the nanoparticles and the long range ordering of block copolymer domains. The first part of the thesis focuses on the study of the effect of nanoparticle inclusions on the phase morphology of the poly(styrene-butadiene) diblock and poly(styrene-butadiene-styrene) triblock copolymers. For gold inclusions, it was found that even at relatively low concentrations of inclusions (less than 1 wt./vol.%) the block copolymer phase morphology is altered from that of the native copolymer. By contrast to the block copolymer-gold system, no significant changes in bulk morphology is observed for similar fullerene concentrations. In the second part of the thesis, the evolution of the order in cylinder forming poly(styrene-butadiene-styrene) triblock copolymer thin films as a function of the type of solvent vapor, exposure time to the saturated vapors and substrate surface energy is discussed. Solvent vapors of dimethoxyethane, ethyl acetate and cyclohexanone were found to be the most effective for our polymer films. Solvent vapors differing in their selectivity towards the block copolymer domains have different kinetics of ordering which is explained in terms of the difference in the interaction of the solvent between the two different copolymer blocks.