The demand for the efficient utilisation of straw biomass requires detailed analyses of its fundamental chemical structures, morphological complexity, individual cell wall components and the correlation of physicochemical to mechanical properties. The study involved two main areas: understanding the details of microstructure and characterisation/differentiation of properties of various profiled wheat straw. Comprehensive and systematic experimental programmes were therefore designed in order to thoroughly investigate the node and internode of wheat straw with quantitative appraisals and qualitative interpretations. This could contribute towards its valorisation in bio-refinery pathways. The sophisticated morphology of node and internode, inner and outer surface was investigated. It was found that the morphology across node area has a great variety when the longitudinal profile is investigated in the upwards direction to grain head. A 3D image of nodes illustrated the dense core with elliptical shaped rings organised in order to provide the echanical strength to the overall stem. The variation of cell wall composition across wheat straw node and internode showed that node yielded slightly higher Klason lignin, extractives and ash content than internode, which could be related to their morphology, precisely the higher ash and extractives content in the node are explained by thicker epidermis tissue. The physicochemical and mechanical properties of node and internode were differentiated and the effects of a combination of mild physical pre-treatment were monitored. The results indicated: i) the reduction of waxes from the outer surface, ii) significantly lower (P < 0.05) extractives and iii) the dissolution of silicon (Si weight %) on the outer surface of node and internode. The tensile strength of nodes and internodes after pre-treatments also resulted in a significant increase (P < 0.05). The accumulated characteristic data enabled the investigation of interfacial properties and bonding mechanisms of the inner and outer surface of wheat straw with thermosetting resins. Different surface functionalities and anatomical sections, altered the bonding performance, i.e. waxes and silica concentrated on the outer surface inhibited the quality of the interface. Nevertheless, the treatment improved interface (P < 0.05) between resins and the micro-porous surface of wheat straw by causing the microcellular structure of straw to expand and hence inspire the mechanical entanglement on a micro level upon resin solidification.

Football is widely regarded as the most popular sport in the world involving over 270 million people from different countries and cultures. It can be argued that the football is one of most important aspects of the game and hence the flight of the ball, if unexpected, can alter the outcome of the game. This thesis provides an engineering perspective and contribution to the continued understanding and improvement of the in-flight performance of FIFA approved footballs. Skilful players will impart spin onto a ball to induce a curve in-flight to try and deceive opponents. This flight is generally smooth, although subtle variations in the orientation and spin rate may cause conditions that affect the path and final ball position, in a manner considered to be unpredictable due to aerodynamic effects. Ball designs and manufacturing techniques are evolving and certain seam configurations are known to induce asymmetric pressure distributions resulting in lateral movement during flight. Aerodynamic research of sport balls has primarily focused on drag and the effects of high spin rates. Studies have shown the introduction of surface roughness affects the boundary layer state compared to a smooth sphere. Surface roughness on a football takes many forms including seam configurations and micro surface textures. The influence of changing the density, distribution and dimensions of the surface roughness with respect to the aerodynamic behaviour has been researched. The principle focus of this thesis is concerned with the influence on the lateral component as a result of applying surface roughness to the outer surfaces. The influence of the surface roughness on the drag and lateral components were determined using established wind tunnel techniques. Real balls and full size prototypes were tested. A mathematical flight model was employed to simulate realistic multiple flight trajectories based on empirical aerodynamic data. Mathematical and statistical techniques, including R.M.S and AutoCorrelation Functions were used to analyse the data. The results from this research showed how small variations in surface texture affected the complex nature of the lateral forces. Trajectories varied significantly depending on initial orientation and slow spin rate sensitivities. In conclusion, ball characterisation techniques were developed that identified lateral deviation and shape measures and considered a gradient profiling approach. Application of these novel parameters through multiple trajectory analysis allowed for an in-flight performance measure of footballs designs.

In 1 Kings 1-2 King David’s impending death divides the monarchy over which of his two sons, Adonijah or Solomon, should be the future king. At this pivotal moment one might expect YHWH to reveal who should take over after David, as YHWH had done before (1 Sam 9:1-10:1; 16:1-13); however, YHWH is silent and the human characters take the lead. Nevertheless, YHWH has not disappeared completely from 1 Kings 1-2 because, as the narrative unfolds, YHWH is invoked twenty-four times. Although this language has drawn some attention, with scholars arguing that it either adds theological validation to the characters’ actions or re"ects a theological perspective that assumes that YHWH acts behind the scenes, there is more that might be said regarding its function in the narratives. In this study, I adopt narrative criticism to undertake a close reading of 1 Kings 1-2 that pays particular attention to how characters and the narrator use invocations of YHWH and the events in the plot that prompt or result from this language. I argue that invocations of YHWH have a number of functions in 1 Kings 1-2, with the function of characters’ invocations being particularly dependent on the identities of the characters, their relationships, and the narrative contexts in which they participate.

Orientador: Marcelo dos Santos Pereira / Banca: Herman Jacobus Cornelis Voorwlad / Banca: Antonio Jorge Abdalla / Resumo: Foram caracterizados os comportamentos eletroquímicos e avaliadas as resistências à corrosão das ligas aeronáuticas 2024-T351 e 7050-T7451 em soluções aquosas de cloreto contendo cromato, molibdato e tungstato. Foram realizados ensaios de corrosão não-eletroquímicos de imersão prolongada acompanhados de análise metalográfica de superfície por microscopia óptica e identificação dos produtos de corrosão por difratometria de raios-X. A análise quantitativa de superfícies das ligas após a imersão, indica que os pites formados têm áreas médias similares. Os pites são mais largos do que profundos e de geometria, predominantemente, cônica ou quase-cônica e irregular. Em todos os produtos de corrosão de cada liga foi encontrado hidróxido de alumínio, em suas diferentes formas cristalinas. Medidas de perda de dureza, como uma conseqüência da deterioração superficial, também foram determinadas. Além disso, ensaios eletroquímicos como medidas de potencial em circuito aberto, curvas de polarização e voltametria cíclica complementaram este estudo. Em meio aerado os resultados obtidos mediante medidas eletroquímicas são consistentes com aqueles obtidos nos ensaios de imersão, em particular o efeito do CrO42- e do MoO42-. O WO42- mostrou-se agressivo em períodos prolongados de imersão. Apesar dos ensaios revelarem uma redução parcial de MoO42- em ambas as ligas, o efeito desse oxi-ânion parece ser diferente sobre cada liga. Em meio desaerado as ligas apresentam passivação em todos os eletrólitos. A adição dos oxi-ânions não modificou significativamente o potencial de pite para a liga 7050, enquanto que para a liga 2024 ele foi deslocado levemente para valores mais positivos. / Abstract: It has been characterized the electrochemical behavior and evaluated the 2024-T351 and 7050-T7451 aircraft alloys corrosion resistance in chloride aqueous solutions containing chromate, molybdate and tungstate. It has been carried out non-electrochemical long immersion corrosion testings accompanied by surface metalography analysis achieved by light microscopy and corrosion products identification by X-ray difratometry. Surfaces quantitative analysis upon the alloys after immersion, indicates that formed pits have similar average area. Pits are widther than deeper and own predominantly a conical or quasi-conical and irregular geometry. In all corrosion products of each alloy it has been found aluminum hydroxide in its different crystalline ways. Hardness loss measurements have also been determined. In addition, electrochemical testings such as open circuit potential measures, polarization curves and cyclical voltammetry have completed this study. In aerated means the obtained results before electrochemical mesurements are similar to those obtained in the immersion tests, in particular CrO42- and MoO42- effects. WO42- has been found to be aggressive in very long immersion period. Though tests display a MoO42- partial reduction in both alloys, this oxi-anion effect seems to be different upon each alloy. In de-aerated means alloys present passivation in all eletrolytes. Oxi-anion addition has not changed significantly pit potential for 7050 alloy, while for 2024 alloy it has been dislocated, slightly, for more positive values. / Mestre

The efficacy of combined diamond and diamond like carbon coatings, to allow for effective and efficient dry turning of aluminium alloy Al 6082, has been investigated. Optimised diamond and diamond-like carbon (DLC) coatings were combined and deposited onto a WC-Co insert using chemical vapour deposition (CVD) methods. DLC coatings were developed by testing the effects of bias voltage, deposition time and gas pressure. During the development of the DLC layer, the effects of substrate geometry and positioning in the deposition chamber were investigated. It was discovered that coating characteristics could vary significantly across the samples as a result of geometrical effects. This contradicted claims that, as plasma enhanced CVD is a non-line of sight deposition method, any variation in the coating due to geometry would be negligible. SEM analysis revealed coating thickness to increase by over 50%. AFM measurements showed coating roughness to increase by up to 30 times, whilst Raman spectroscopy highlighted a significant decrease in sp3 bonding. This variation in characteristics was seen, through the use of scratch testing, to translate into significantly reduced tribological performance. Friction was increased by 60% and critical load was only half of that of the coating applied to flat surface. The combined coatings were characterised and machining performance was evaluated. Coating characteristics were examined using SEM, AFM and Raman spectroscopy. Cutting trials designed to simulate the expected tool life were conducted. Micro and nano-crystalline diamond coatings, with and without an additional DLC layer were trialled along with a single layer DLC coating. Commercially available uncoated and TiN coating inserts of identical geometry were also trialled as a reference. The results showed that the addition of the DLC layer effectively reduced the roughness of the diamond, however, this did not translate into reduced adhesion of the aluminium to the cutting tip. It has been shown that for this particular machining scenario, a smoother coating effectively increased friction and adhesion of the workpiece material. The investigation has highlighted that due to the complex dynamics of material transfer effects in sliding, it cannot be assumed that a smoother surface layer will lead to improved tribological performance.

The rapid development of nanotechnology has caused concerns about nanoproducts on human health throughout their lifecycle. As part of the consortium NEPHH (nanomaterial related environmental pollution on human health through their life cycle, funded by EU-FP7), this project aimed to assess the potential effect of novel polymer-silicon composites on human health from a lifecycle perspective, focusing on in vitro toxicity of raw silica nanoparticles (SiNP) and dust nanoparticles (NP) released from silicon-based polymer composites. The main objectives were to characterise a group of amorphous SiNP and dust NP in water and cell culture medium; assess NP toxicity potential in in vitro models; and establish mode of SiNP action. The selection of SiNP of size 7-14 nm was based on their wide use in developing polymer nanocomposites. Dust NP were generated from mechanical processing of polymer composites made of polyamide-6 (PA6), polyurethane (PU) and polypropylene (PP), each incorporated with SiNP or 3 other different silicon reinforcement materials. The dispersion and size of NP in water and in cell culture medium were characterized using dynamic light scattering, scanning electron microscopy and transmission electron microscopy. The chemical composition of NP was assessed by infra-red spectroscopy. NP were assessed in vitro for induction of membrane damage, intracellular reactive oxygen species (ROS), loss of cell viability, and cellular uptake by flow cytometry and confocal microscopy. In order to identify potential biomarkers for toxicity prediction, miRNA array and extracellular metabonomic assays were performed. The size of SiNP (10-100 µg/ml) ranged from ~200-500 nm in water and ~20- 500 nm in culture medium, indicating the presence of aggregates. The infra-red spectrum of SiNP dried from culture medium showed a slight difference as compared with that dried from water, indicating protein adsorption. SiNP induced acute ROS increase, cell membrane damage, and reduction in cell viability after 48 h in human lung carcinoma epithelial A549 cells, lung fibroblast MRC-5 cells and skin HaCaT keratinocytes. SiNP were up taken by all 3 cell types, and located in the cytosol. Six early ( < 48h) SiNP responsive miRNAs were identified in A549 cells. SiNP also induced early changes in metabolites including glucose, lactate, ethanol, phenylalanine, histidine and tyrosine. Dust NP generated from PA6 group materials were more toxic than those from other polymer composites when assessed at 25-100 µg/ml at 72 h in A549 cells. The results obtained from this study suggest that 1) both small and larger SiNP aggregates are taken up into the target cells; 2) conventional cytotoxicity assays combined with miRNA and metabonomic assays provide insight into the molecular mechanisms of the nanotoxicity; 3) metabonomics and miRNA assays can serve as robust tools for recognising sub-toxic dose-effect relationships; 4) the toxicity of dust NP from polymer composites depends on polymer type but not reinforcement materials. This study demonstrated the importance of lifecycle analysis as opposed to single stage analysis of novel materials. Further studies need to improve study design to enable interpretation of cytotoxicity in relation to NP size, physiochemical property and intracellular dose, and to simulate the health effect of polymer-silicon composites under more realistic scenarios.

In many instances the properties of a network are obstructed by an intervening network, which is required when performing measurements of the network. These intervening networks are often in the form of a mode transformer and are, in the general sense, referred to as error networks. A new analysis mechanism is developed by applying a de-embedding method that was identified as being robust. The analysis was subsequently implemented in a numerical computational software package. The analysis mechanism can then be applied to perform the characterisation of error networks. The performance of the analysis mechanism is verified using an ideal lumped-element network. The limitations of the mechanism are identified and possible ways of addressing these limitations are given. The mechanism is successfully applied to the characterisation of three different microwave networks. / Dissertation (MEng)--University of Pretoria, 2013. / gm2014 / Electrical, Electronic and Computer Engineering / unrestricted

Protein based biopharmaceuticals are becoming increasingly popular therapeutic agents. Recent changes to the legislation governing stem cell technologies will allow many further developments in this field. Characterisation of these therapeutic proteins poses numerous analytical challenges. In this work we address several of the key characterisation problems; detecting glycosylation, monitoring conformational changes, and identifying contamination, using vibrational spectroscopy. Raman and infrared spectroscopies are ideal techniques for the in situ monitoring of bioprocesses as they are non-destructive, inexpensive, rapid and quantitative. We unequivocally demonstrate that Raman spectroscopy is capable of detecting glycosylation in three independent systems; ribonuclease (a model system), transferrin (a recombinant biopharmaceutical product), and GFP (a synthetically glycosylated system). Raman data, coupled with multivariate analysis, have allowed the discrimination of a glycoprotein and the equivalent protein, deglycosylated forms of the glycoprotein, and also different glycoforms of a glycoprotein. Further to this, through the use of PLSR, we have achieved quantification of glycosylation in a mixture of protein and glycoprotein. We have shown that the vibrational modes which are discriminatory in the monitoring of glycosylation are relatively consistent over the three systems investigated and that these bands always include vibrations assigned to structural changes in the protein, and sugar vibrations that are arising from the glycan component. The sensitivity of Raman bands arising from vibrations of the protein backbone to changes in conformation is evident throughout the work presented in this thesis. We used these vibrations, specifically in the amide I region, to monitor chemically induced protein unfolding. By comparing these results to fluorescence spectroscopy and other regions of the Raman spectrum we have shown that this new method provides improved sensitivity to small structural changes. Finally, FT-IR spectroscopy, in tandem with supervised machine learning methods, has been applied to the detection of protein based contaminants in biopharmaceutical products. We present a high throughput vibrational spectroscopic method which, when combined with appropriate chemometric modelling, is able to reliably classify pure proteins and proteins ‘spiked’ with a protein contaminant, in some cases at contaminant concentrations as low as 0.25%.

Molecular management targets the right molecules to be at the right place, at the right time and at the right price. It consists of molecular characterisation of refining streams, molecular modelling and optimisation of refining processes, as well as overall refinery optimisation integrating material processing system and utility system on the molecular level. The need to increase modelling details to a molecular level is not just a result of political regulations, which force refiners to managing the molecule properly, but also seems to be a very promising to increase the refining margin. In this work, four aspects of molecular management are investigated respectively. Molecular Type Homologous Series (MTHS) matrix framework is enhanced on both representation construction and transformation methodology. To improve the accuracy and adequacy of the representation model, different strategies are formulated separately to consider isomers for light and middle distillates. By introducing statistical distribution, which takes the composition distribution of molecules into account, the transformation approach is revolutionised to increase the usability, and tackle the challenge of possibly achieving significantly different compositions from the same bulk properties by the existing approaches. The methodology is also enhanced by applying extensive bulk properties. Case studies demonstrate the effectiveness and accuracy of the methodology. Based on the proposed characterisation method, refining processes are modelled on a molecular level, and then process level optimisation is preformed to have an insight view of economic performance. Three different processes, including gasoline blending, catalytic reforming, and diesel hydrotreating, are investigated respectively. Regarding gasoline blending, the property prediction of blending components, and the blending nonlinearity are discussed. To tightly control on the property giveaway, a molecular model of gasoline blending is developed, and then integrated into the recipe optimisation. As for the conversion processes, catalytic reforming and diesel hydrotreating, reactions and reactors are modelled separately, and then followed by the consideration of catalyst deactivation. A homogeneous rigorous molecular model of a semiregenerative catalytic reforming process, considering pressure drop, has been developed. In addition, a multi-period process optimisation model has been formulated. Regarding diesel hydrotreating, a molecular model of reactions with a three-phase trickle-bed reactor has been developed. The concept of reaction family is successfully applied. A structural contribution approach is used to obtain kinetics and adsorption parameters. A series of procedures are developed to solve the complex problem. Thereafter, a process optimisation model has been developed with the consideration of catalyst deactivation, with a new strategy on the division of catalyst life. Finally, a two-level decomposition optimisation method is extended to incorporate molecular modelling into the overall refinery optimisation, and then applied in two aspects. Firstly, with the integration of the process and the site-level models, a better perspective is obtained with regard to a material processing system. By molecular modelling of refining streams and processes, the integrated approach not only controls the molecules in products properly, but also increases the overall performance. In the second application, a framework integrating a hydrogen network with hydroprocesses is developed to target the maximum profit, rather than saving hydrogen. It allocates hydrogen on the hydrogen network level and utilise hydrogen efficiently on the process level by optimising operating conditions. Consequently, the extent of achieving the maximum profit could be fully exploited with optimal hydrogen utilisation.

The growing number of micro generation devices in the electrical network is leading many to consider that these devices can no longer be considered as fit and forget, but should instead be considered as having a demonstrable network impact which should be predicted and utilised. One of the techniques for considering the impacts of these devices is the Virtual Power Plant (VPP). The VPP is the aggregation of all the Distributed Generation (DG) connected into the network up to and including the connection voltage of the VPP, such that the cumulative power up the voltage levels can be seen in the single VPP unit, rather than across a broad spread of devices. One of the crucial tasks in characterising the VPP, developed in this work, is the ability to correctly predict and then aggregate the behaviour of several technology types which are weather driven, as a large proportion of DG is weather driven. Of this weather driven DG, some can only typically be dispatched with modification and the rest cannot be dispatched at all. The aggregation of the VPP as part of the electrical network is also developed, as the constraints of the network and the reliability of the network cannot be overlooked when considering the aggregation of the VPP. From a distribution network operator's (DNO) perspective, these characterisation models can be used to highlight problems in the network introduced by the addition of DG, but are also generally utilitarian in their role of predicting the power output (or negative load) found throughout the network due to DG. For a commercial agent interested in selling energy, these models allow for accurate predictions of energy to be determined for the trading period. A VPP agent would also be adversely affected by line failure in the network, leading to the development of an N-1 analysis based upon reliability rates of the network, which is used as the basis for a discussion on the impacts of single line failure and the mitigation available through feedback from the DNO.