Analysing Frequency Selective Surfaces (FSS) often requires solving integral equations that may have asymmetric and singularity behaved kernels. These singularities together with the array geometry can introduce significant complexities to the solution of the problem. The thesis deals with the solution of such equations using a spectral iterative method. The analysis is based on minimising an error criterion, which is defined as the difference between the scattered and impressed waves. Computer models have been developed as a means of predicting the radiation performance of single and multiple layer FSS. The research involves two separate but related studies. The first study is concerned with finite arrays of conducting elements. The effect of the dielectric substrate and size of the arrays to the scattered field is examined. In the second study the iterative scheme is modified accordingly in order to solve a set of integral equations for a multilayer array where each layer is assumed to be of infinite extent. The analysis takes into account the interlayer coupling and the dielectric substrates/superstrates adjacent to the array elements. The results obtained from both studies are compared with the method of moments solution as well as with experimental results.

In marine environments and where de-icing salts are applied, the degradation of reinforced concrete structures due to chloride induced corrosion of the reinforcement is a major problem. The expansive nature of the corrosion process results in cracking of the concrete and eventually spalling. In order to select suitable remedial measures it is necessary to make an assessment of the residual strength and the residual life. In order to investigate the effect of corrosion on bond strength of the reinforcement, specimens comprising square prismatic sections containing steel reinforcement in the four corners have been subjected to a wet-dry cycle and corrosion has been accelerated by polarising the bars. The research has studied the change of bond strength with level of corrosion for 12 mm and 16 mm bars with concrete cover of 1 and 3 times the bar size. The bond strength is assessed by means of pull out tests and the corresponding extent of corrosion has been assessed in terms of the mass loss. Observations and measurements of the form of the corrosion (pit dimensions and loss of bar diameter) are also presented. The relationship between bond strength and surface crack width has been investigated. Results show that the surface crack width may be a good indicator of residual bond strength. In addition, the influence on bond strength of concrete compressive strength, reinforcement cover, bar position and bar size on the change of bond strength has been explored. It should be noted that all conclusions drawn in this project are based on tests on specimens without shear reinforcement (unconfined) and that accelerated corrosion (by impressed current) has been adopted. Consequently, care should be exercised in applying these results directly to structures in the field. Additional research is needed to assess the influence of impressed current on crack patterns and the effect of shear reinforcement.

This thesis represents a study of textile-impressed ceramics from Slack Farm, a Late Mississippian Caborn-Welborn phase site in Union County, Kentucky. The goal of this study was to use the textile impressions to provide additional insight into Caborn-Welborn social organization. The Caborn-Welborn phase represents the reconfiguration of communities in the Lower Ohio River Valley after the collapse of the Angel chiefdom and other nearby Mississippian polities. Results indicate that there was an increase in textile structural variation in the fabric used for the impressions at Slack Farm and other Caborn-Welborn sites from earlier Mississippian assemblages. Increased textile structural variation may be associated with the reconfiguring of the Caborn-Welborn social organization during this phase. Textile types associated with Oneota tribal groups were also identified at Slack Farm and suggest Oneota women were in residence at the site. Textile patterns assumed to be associated with an elite status were not identified in this study. Overall, the textile-impressed assemblage reflects the response of weavers to changes in the Caborn-Welborn social organization.

Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter Narrows pottery represented an incursion of the plains adapted Old Womens phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p> Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.

Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter "Narrows" pottery represented an incursion of the plains adapted Old Women's phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p> Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.

Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter Narrows pottery represented an incursion of the plains adapted Old Womens phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p> Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.

Recent archaeological surveys on Peter Pond Lake have provided an opportunity to better elucidate the Late Woodland period of occupation in the upper Churchill River basin of northwestern Saskatchewan. Previous studies identified two pottery-bearing cultures in the region. This included the Kisis complex of the well-documented Selkirk composite, which is characterized by Winnipeg Fabric-impressed ware and dates from approximately A.D. 1300 through to the historic period. The second was a lesser-known archaeological entity represented by limited pottery recoveries from just two sites in the region. Early interpretations proposed this latter "Narrows" pottery represented an incursion of the plains adapted Old Women's phase into the region, with a suggested age of approximately A.D. 1000 to 1300. <p> Through a comprehensive analysis of pottery assemblages recently recovered from over twenty sites in the Peter Pond Lake region, this study was able to further validate the original description of the Kisis complex, but more significantly, propose a new pottery ware and complex for the enigmatic Narrows pottery assemblages. As a result, this pottery is now formally classified as Narrows Fabric-impressed ware and is considered characteristic of the Buffalo Lake complex. This complex is centered on Peter Pond Lake and appears to have an extensive presence in the region. Recently obtained radiocarbon dates indicate it is slightly younger than originally believed, and spanned from approximately A.D 1200 to 1500. Unlike previous interpretations, which suggest this pottery represents a plains influence in the region, the Buffalo Lake complex is considered a boreal forest manifestation, with origins that lie in the woodlands to the southeast. The pottery shares particular affinities with contemporaneous Sandy Lake ware that has a distribution extending from east-central Saskatchewan through to northwestern Ontario and Minnesota, with additional influences evident from Winnipeg Fabric-impressed ware found throughout northern Saskatchewan, Manitoba and Ontario.

abstract: This dissertation examines the various factors and processes that have been proposed as explanations for the spread of agriculture in the west Mediterranean. The expansion of the Neolithic in the west Mediterranean (the Impresso-Cardial Neolithic) is characterized by a rapid spread of agricultural subsistence and material culture from the southern portion of the Italian peninsula to the western coast of the Iberian peninsula. To address this unique case, four conceptual models of Neolithic spread have been proposed: the Wave of Advance, the Capillary Spread Model, the Maritime Pioneer Colonization Model and the Dual Model. An agent-based model, the Cardial Spread Model, was built to simulate each conceptual spread model in a spatially explicit environment for comparison with evidence from the archaeological record. Chronological information detailing the arrival of the Neolithic was used to create a map of the initial arrival of the Neolithic (a chronosurface) throughout the study area. The results of each conceptual spread model were then compared to the chronosurface in order to evaluate the relative performance of each conceptual model of spread. These experiments suggest that both the Dual and Maritime Pioneer Colonization models best fit the available chronological and spatial distribution of the Impresso-Cardial Neolithic. For the purpose of informing agent movement and improving the fit of the conceptual spread models, a variety of paleoenvironmental maps were tested within the Cardial Spread Model. The outcome of these experiments suggests that topographic slope was an important factor in settlement location and that rivers were important vectors of transportation for early Neolithic migration. This research demonstrates the application of techniques rare to archaeological analysis, agent-based modeling and the inclusion of paleoenvironmental information, and provides a valuable tool that future researchers can utilize to further evaluate and fabricate new models of Neolithic expansion. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2016

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[pt] A corrosão é a patologia mais recorrente no concreto armado, responsável por custos elevados na recuperação das estruturas afetadas. Além dos custos diretos como os materiais utilizados na recuperação, a mão de obra especializada, substituição de peças ou equipamentos afetados, existem os custos indiretos como a paralização da utilização da estrutura, mobilização de moradores em caso de edificações residenciais, perda de produção em caso de edificação industriais, entre outros. Encontrar e apresentar meios para o combate e a prevenção da corrosão é de extrema importância. A proteção catódica tem se apresentado nas últimas décadas como uma forma eficaz de combate a corrosão, não só paralisando o processo corrosivo totalmente, mas também prevenindo o surgimento de novos pontos. Seu uso vem sendo aplicado cada vez mais em estruturas de concreto armado, como pontes, cais, edifícios industriais e residenciais e túneis. Diversos materiais vêm sendo testados e aprovados, possibilitando a flexibilização e a adaptação do melhor sistema para cada estrutura. Relatos de casos com uso da proteção catódica tem mostrado a sua eficácia mesmo depois de anos de instalação. Essa dissertação apresenta a proteção catódica, seus sistemas de uso, casos em que foi instalada, um experimento com proteção catódica por corrente impressa para a restauração de uma ferramenta de aço, além de um modelo computacional desenvolvido para o dimensionamento de anodos galvânicos para estruturas de concreto armado. / [en] Corrosion is the most recurrent pathology in reinforced concrete, responsible for high costs in the recovery of affected structures. In addition to direct costs such as materials used in the recovery, specialized labor, replacement of affected parts or equipment, there are indirect costs such as the interruption of use of the structure, mobilization of residents in case of residential buildings, loss of production in case of industrial buildings, among others. Finding and introducing means to combat and prevent corrosion is extremely important. Cathodic protection has been presented in the last decades as an effective way to combat the corrosion, as it not only paralyzes the corrosive process completely, but also preventing the combat to new points. Its use has been increasingly applied in structures such as bridges, industrial and residential buildings, and tunnels. Various materials have been tested and approved, adaptation system for flexibility and adaptation to better each structure. Case reports with the use of cathodic protection have had attention even after years of installation. This dissertation presents cathodic protection, its systems of use, cases in which it was installed, an experiment with cathodic protection by impressed current for the restoration of a steel tool, as well as a computational model developed for the design of galvanic anodes for reinforced concrete structures.