Made available in DSpace on 2014-10-09T12:50:01Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:01Z (GMT). No. of bitstreams: 1 10429.pdf: 3578443 bytes, checksum: fe5754a99670b4c0386123d29758d3c4 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

This diploma thesis contains theoretical and practical parts: 1. Practical part: - contains a collection of nine illustrations to the book {\clqq} A Man with a Pipe and Violin`` by Arthur Conan Doyle ( original number of ten works was decreased because of incogruity of separate stories {--} the book is the choice carried out differently compared to original intention of the autor and the higher number seemed to affect the general composition to the prejudice of uniformity. - Illustrations are performed by combined technique - They are presented free (without passe-partout) - Preparatory sketches and experimental prints are enclosed in practical part 2. Theoretical part: - Contains three parts - Essay on illustration field - Analysis of the book and the reasoning of inspiratory impacts

Made available in DSpace on 2014-10-09T12:50:01Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:01Z (GMT). No. of bitstreams: 1 10429.pdf: 3578443 bytes, checksum: fe5754a99670b4c0386123d29758d3c4 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Intermediate phases in two non-ionic polyoxyethylene surfactantiD20 systems - nonaethylene glycol mono (1 1-oxa-14,18,22,26-tetramethylheptacosyl) ether (C30E09) and hexaethylene glycol n-hexadecyl ether (C15E05) have been studied. Both systems have a rhombohedral mesh phase with the space group symmetry R3m, and model calculations show this phase to consist of hexagonally arranged pores in a surfactant bilayer. The formation of this phase is driven by the need to introduce curvature into the interface as the temperature decreases and hydration of the ethylene oxide headgroups increases. In the C30E09 system a small angle neutron scattering study on a 42 wt.% sample has allowed the epitaxial relationship between the lower temperature hexagonal (H1) phase and the mesh intermediate phase, with the (10) planes of the H 1 phase becoming the (001) planes of the mesh phase. The concentration interval of 48 - 62 wt.% of the C 1 6E06 system has been studied using optical microscopy, 2H nuclear magnetic resonance, and small angle scattering in order to establish the detailed phase behaviour. On cooling from the lamellar phase, the phase sequence observed is defected lamellar, mesh intermediate, Ia3d cubic, and hexagonal plus gel. On heating from the hexagonal plus gel phase region, the intermediate and cubic phase observed upon cooling is replaced by an Ia3d cubic phase region. The mesh intermediate forms when the water filled defects of the higher temperature defected lamellar phase correlate between the surfactant layers. The C16E06 system has been perturbed by the inclusion of either the shorter chain surfactant hexa-ethylene glycol mono n-dodecyl ether (C12EO6) or the oil octadecane (C 1 81-138). The addition of C12E05 promotes aggregate structures with more curved interfaces, and the intermediate mesh phase is eliminated in favour of the Ia3d cubic phase. The addition of C181-138 swells the surfactant bilayers and promotes flatter interfaces, but does not stabilise the intermediate phase, as only small additions of oil suppress this phase.

Streptomyces clavuligerus was grown in nutrient-limited defined media in laboratory scale fermenters using continuous and batch culture methods. Cephamycin C was produced in all fermentations. Clavulanic acid was produced in carbon- and nitrogenlimited continuous culture and in carbon- and phosphate-limited batch culture. Low levels of intracellular guanosine 5'-diphosphate 3'-diphosphate (ppGpp) were detected at D= 0.02 h' in continuous culture in all media. Low levels of intracellular guanosine 5 '-diphosphate 3 '-monophosphate (ppGp) were detected at D=0.02 if' in carbon- and nitrogen- limited media. ppop was not detected under phosphate limitation at any dilution rate. Increased production of cephamycin C was observed at D=0.02 If' under nitrogen limitation coinciding with the detection of elevated levels of ppGpp, ppGp and ATP. Increased production of clavulanic acid was observed at D=0.02 If' under carbon limitation coinciding with the detection of elevated levels of ppGpp and ppGp. There was no correlation between dilution rate and basal levels of either ppGpp or ppGp in any growth-limiting medium. ppGpp was produced at low levels in carbon- and nitrogen-limited batch fermentations prior to the detection of cephamycin C and clavulanic acid in the medium. High levels of ppGpp were detected under phosphate limitation immediately prior to the transcription of cas, the gene encoding clavaminate synthase. High levels of ppGp were detected in all batch fermentations following a downturn in nitrogen and carbon levels and immediately prior to the detection of isopenicillin N synthetase (IPNS). ppGp was detected following nutrient shifidown by amino acid depletion and was not produced via degradation of ppGpp. The results point to a possible role for ppGpp in the regulation of clavulanic acid synthesis under phosphate limitation only, and a potential role for ppGp in the regulation of cephamycin C production in Streptomyces clavuligerus.

The effect of damage on carbon-fibre reinforced poly(aryl suiphone) by a solvent of the type used by BAe Military Aircraft Division as a paint stripper has been investigated together with the effect of fibre waviness upon the mechanical strength of carbon-fibre reinforced poly(aryl suiphone). Mathematical models for solvent effects were derived and comparison was made with the practical results obtained both from tension loading and three-point loading in bending. Good agreement between the theoretical and test results has been observed. It was found that solvent damage is minimal on the tensile behaviour of (90,0)s laminates but caused a reduction in the strain at failure in (0,90)s laminates. Theoretical models were developed for fibre waviness, where the waviness is in the plane of the ply. The theoretical results are compared to the results of tensile testing. It is reported that, contrary to the work of others, fibre waviness can have a marked affect on laminate behaviour in tension and, for a wave ratio of 0.1, can cause the load at failure in cross-plied laminates to be reduced to only 24% of the the load at failure in an equivalent laminate free of fibre waviness. Specimens were put through heating and cooling cycles in order to reduce residual stresses. Estimates of the value of these stresses were based upon the curvature of asymmetric laminates. The results compared favourably with published values for similar materials. Various 'protective' coats were investigated to reduce the amount of solvent damage. One protective coat was found to give reduced damage with increasing coats. Test results were compared to those obtained from (i) The Tsai-Hill failure criterion, (ii) The Han-Smith maximum shear stress criterion. The test results were found to be in good agreement with both criteria when failure did not occur at positions containing fibre waviness. When failure occurs at fibre waviness it is demonstrated that if the exact point of failure within fibre waviness is known then corrections can be made to the test results. When the corrections were made there was good agreement between test results and both criteria.

Despite being Britain's most extensive semi-natural habitat, less research has been carried out on blanket mires than on many other habitats. This is possibly a result of their relative inaccessibility, since they are mainly confined to upland areas in England and Wales and remoter parts of Scotland; also to their apparent abundance, given that they cover significant portions of the landscape. Blanket mires in Britain cover approximately 1.5-2 million hectares; studies have documented substantial losses and up to ninety percent of blanket mires in Britain have been adversely affected. Literature on blanket mires suggests that poor management is one of the key issues for this habitat together with a lack of financial resources and commitment by the Government to protect and conserve sites adequately. The range of land uses of blanket mires is complex and includes agriculture, conservation, recreation, water catchment, grouse and deer management and forestry. These various uses have led to conflict among certain groups and a number of uses have had a detrimental effect on this habitat. Often the value of blanket mires has been overlooked even though this habitat, as part of natural ecosystem process, can provide functions and services such as wildlife interest and hydrological supply systems. A gap has been identified in the current literature on blanket mires, which suggests that research into the broader issues of strategy and management of this habitat, by organisations, landowners and farmers, has not been undertaken. Interview data have been obtained from organisations, landowners and farmers involved with blanket mire management and assessed by interpretational analysis. The research has been carried out both at a national level in Britain and at a local level with a case study of the Forest of Bowland in Lancashire. The local case study has been related to the wider context of blanket mire management and conservation. A total of fifty four in-depth interviews were undertaken in order to gain information on the views, perspectives and experiences of those involved with blanket mire management. How blanket mires are valued has a significant impact on how peatlands are conserved and for what reason. This research reveals that, in order to be effective, organisations will have to have a clear vision of what end point they are working towards and devise practical sategies that are flexible enough to incorporate the distinctiveness of different blanket mire areas.

The binary surfactant system nona (ethylene glycol) mono-( 11 -oxa- 14,18.22,26-tetramethylheptacosylether) in heavy water has been investigated using deuterium nuclear magnetic resonance, optical polarising microscopy and small angle scattering techniques. The phase diagram has been established and the phases encountered exist for the most part from 24 to 60% surfactant by weight. Above and below these concentrations exist isotropic and lamellar phases respectively. The phase diagram features three main phases, a hexagonal phase of circular rods, a lamellar phase and an intermediate phase. The length of the alkyl chain is shown to be the most important factor in stabilising intermediate phases in preference to the bicontinuous cubic phases usually encountered between hexagonal and lamellar phases in shorter chain homologues. A nematic phase has also been observed in the water penetration scan. The intermediate phase is extensive, ranging from 32 to 60% surfactant by weight and is about 5°C wide. It has a body centred tetragonal mesh structure, comprised of layers of surfactant with regularly spaced holes which are also correlated between the layers, the hole of one layer overlapping the intersection of the layer below. As the concentration is decreased, from 60% to 30% (surfactant by weight) this correlation relaxes. The actual form of the aggregate appears to be elliptical rods (ellipticity - 1.7) joined four by four to form the basis of the mesh structure. A simplified version of the model based on circular rods joined by cube junction regions has been used to quantitatively investigate this phase. The results from this crude model produce results very close to those anticipated and produces results to within 2% of those generated using a more sophisticated model. This system is unusual in that the nature of the interaction between aggregates appears to be dominated by a single interaction - 'headgroup overlap force. This arises from the repulsive pressure experienced by the headgroups penetrating from the aggregate interface and also between headgroups on the same aggregate.

Components found within many industries contain crack like defects. The work detailed here considers such a component under the combined influence of primary and secondary stresses; where primary stresses contribute to plastic collapse and secondary stresses are redistributed under plastic deformation. A number of approaches are available to detail the combined loading on the crack tip parameter J, or KJ, which is used to assess proximity to failure from crack extension. However, these approaches are recognised to be conservative and can lead to the unnecessary replacement of components, stricter surveillance and inspection regulations, and further costs associated with downtime.The aim of the work presented is to investigate these conservatisms and develop a further approach to quantify the interaction of primary and secondary stresses on fracture. A large matrix of cracked body finite element analyses of a circumferentially cracked cylinder has been performed under a range of loadings. This is then used to detail the interaction of primary and secondary stresses on fracture by providing a function to describe a scaling term, g, that multiplies the secondary crack driving force contribution. This term has been shown to be relatively independent on the magnitude of secondary stresses and is also dependent on the material stress strain relation. This relation for g has also been shown to be compatible with the R6 defect assessment procedures V factor approach, through the Vg plasticity interaction term, that provides a scaling term to the secondary contribution in R6. A review of experiments considering combined loading has indicated that the number of tests that cover a range of primary stress induced plasticity levels is limited. Further experiments were therefore considered within this research to provide added experimental fracture toughness data by which to compare the R6 V factor and Vg approaches. These experiments introduced a compressive pre-load to the ends of three-point bend specimens so that a tensile residual stress resulted on unloading. A crack was introduced and the specimens tested at one of three temperatures so that changes in the materials fracture toughness with temperature ensured different levels of plasticity at failure; so that crack growth occurred over three sets of load normalised to the load for plastic collapse. Tests were also conducted that did not include the residual stress so that the effect of residual stress could be shown under different levels of plastic redistribution. The Vg Approach and the existing Complex R6 V Approach have then been applied to all available experimental data for validation. The results show that both approaches conservatively predict the failure of all tests and that the Vg Approach can reduce the level of conservatism.

In this research, a new combined heat and power (CHP) system configuration has been proposed that uses two power generation units (PGU) operating simultaneously with different operational strategies (D-CHP). The performance of the proposed D-CHP system configuration, with one PGU operated at a constant base load and the other operated following the electric load, is quantified in terms of operational cost savings, primary energy consumption (PEC) savings, and carbon dioxide emissions (CDE) savings over a reference case employing a conventional, separate heat and power system. D-CHP system performance is also compared to standard, single PGU operational strategies. The D-CHP system configuration is first examined for four different building configurations simulated using the weather of Chicago, IL. Then, the D-CHP system feasibility study is extended to examine a full-service restaurant benchmark building in nine different U.S. climate zones. Next, the D-CHP configuration is simulated under a second operational strategy, in which one PGU operates base-loaded while the other follows the thermal load, and the two D-CHP strategies are compared. Additionally, the effect of thermal storage on D-CHP system performance is examined. Finally, the D-CHP configuration is extended to a combined cooling, heating, and power configuration (D-CCHP), and the feasibility of this configuration is examined. In addition to D-CHP and D-CCHP systems performance analyses, the parameters of power-to-heat ratio; cost, emissions and primary energy consumption spark spreads; cost and emission ratios; and thermal difference are proposed and examined as performance indicators. It was determined that D-CHP and D-CCHP system strategies can be a viable alternative to traditional CHP system or combined cooling, heating, and power (CCHP) system operational strategies, in terms of operational cost, PEC, and CDE performance. Generally, the D-CHP and D-CCHP configurations are found to perform comparably to or better than traditional CHP and CCHP configurations.