In this research, controlled Waspaloy microstructures were produced with the objective of studying microstructural evolution in this alloy via electrically-based ac/dc non-destructive techniques. Correlations were developed between electrical measurements and alternate characterization techniques such as Ultra Small Angle X-ray Scattering (USAXS), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) to gain a complete understanding of the microstructural transformations and the associated mechanisms. Three different sets of controlled microstructures were produced in this research. In Set I microstructures, matrix (gamma) grain sizes of 13, 52 and 89 micrometers were obtained after solution-treatments at 1045 and 176;C, 1090 and 176;C and 1145 and 176;C respectively. A vacancy stabilization treatment at 1045 and 176;C followed after which, the specimens were aged at 800 and 176;C for times ranging from 0.1 hrs to 100 hrs to vary the gamma prime precipitate size distribution. In Sets II and III, the solution-treatment was only conducted at 1145 and 176;C, with the stabilization treatment conducted only in Set II. Subsequently, aging experiments were conducted at 725 and 176;C (or 700 and 176;C in Set II), 800 and 176;C and 875 and 176;C for times up to 100 hrs. DC four-point probe resistivity of specimens increased to a maximum upon initial aging from the solution-treated condition and showed a decreasing trend thereafter with successive aging. This, in addition to complementary evidence from SEM and USAXS, led to the conclusion that gamma prime nucleation-growth was complete by the time the resistivity maximum was observed. Resistivity variations that ensued upon successive aging after the maximum were attributed to microstructural/compositional changes due to gamma prime coarsening. The height of the maximum decreased drastically with increase in aging temperature from 725 and 176;C to 800 and 176;C, while the resistivity did not increase from the solution-treated condition upon aging at 875 and 176; C. Coarsening studies based on USAXS analysis indicated an LSW type volume diffusion mechanism of coarsening in Waspaloy, with an average coarsening rate constant of 3.25x10-29 [m3/sec] for Set I specimens aged at 800 and 176;C. Analytical and Finite Element (FE) models of two-probe impedance and dc four-point probe resistivity methods were developed to gain insight into the measured response and the accurate determination of material properties. AFM-based localized electrical examination of sub-grain Waspaloy microstructures was successfully conducted using electrostatic force microscopy (EFM), scanning Kelvin probe microscopy (SKPM) and current-AFM (I-AFM) electrical modes. I-AFM experiments revealed that the conductivity of the gamma prime phase was lower than that of the gamma phase.

<p>Determination of the subsurface geology is very important for the rock quarry industry. This is primarily done by drilling and mapping of the surface geology. However in Sweden the bedrock is often completely covered by Quaternary sediments making the prediction of subsurface geology quite difficult. Incorrect prediction of the rock-mass quality can lead to economic problems for the quarry. By performing geophysical measurements a more complete understanding of the subsurface geology can be determined. This study shows that by doing 2D-parallel data sampling a 3D inversion of the dataset is possible, which greatly enhances the visualization of the subsurface. Furthermore the electrical resistivity technique together with the induced polarization method proved to be very efficient in detecting fracture frequency, identification of major fracture zones, and variations in rock-mass quality all of which can affect the aggregate quality. With this technique not only the rock-mass quality is determined but also the thickness of the overburden. Implementation of geophysics can be a valuable tool for the quarry industry, resulting in substantial economic benefits.  </p>

This study assesses the capability and practical applications of quasi 3-Dimensional (3D) electrical resistivity surveying (ER) for mapping air-filled karst conduits. Vadose zone caves within the Brooksville Ridge of West Central Florida are relatively similar in architecture, with N-S elongation, and do not consist of an interconnected network of conduits. A high resolution quasi-3D ER survey was performed over two mapped cave systems on the Brooksville Ridge. The resultant survey verified the general effectiveness of quasi-3D ER in locating the two known near-surface cave features. Several other locations in the survey show similar or stronger resistivity anomalies trending in a N-S direction; these are interpreted to represent previously unknown voids. The quality of inversion results were tested by comparing results against the known void locations and by computing cross-over errors from surveys conducted at the same point with different orientations. Our results show that 3D inversions of multiple adjacent parallel profiles produces higher quality results (lower cross-over errors, better fit to cave locations) than 2D inversions. The data indicate that no single value of resistivity can be used as a reliable indicator of the presence of a void, presumably due to variable void size and the complexity in resistivities in the host rock. With sinkholes continuing to be of concern to residential and urban development in West Central Florida, the results of this research show the necessity of applying geophysical techniques in order to reduce the potential hazards posed by karst terrain.

Many Ministry of Transportation of Ontario (MTO) projects consist of construction and maintenance of reinforced concrete structures. Where appropriate test methods exist, MTO has been moving towards use of performance-based specifications for durability control of concrete. MTO currently uses ASTM C1202 (RCPT) coulomb values to assess concrete durability. This test requires taking cores, so replacing this test with a faster non-destructive technique is important. The main focus of this program was to study the Wenner probe surface resistivity as a non-destructive test device and evaluate the potential for replacement of RCPT with the Wenner resistivity. This research program consists of the determination of RCPT values, water sorptivity coefficients and electrical resistivities (bulk and surface) of nine concrete mixtures. In addition, the development of the Wenner probe instrument was studied. As well, correlations between resistivity and ASTM C1202 and C1585 are provided followed by technical recommendations for improving the Wenner test.

Many Ministry of Transportation of Ontario (MTO) projects consist of construction and maintenance of reinforced concrete structures. Where appropriate test methods exist, MTO has been moving towards use of performance-based specifications for durability control of concrete. MTO currently uses ASTM C1202 (RCPT) coulomb values to assess concrete durability. This test requires taking cores, so replacing this test with a faster non-destructive technique is important. The main focus of this program was to study the Wenner probe surface resistivity as a non-destructive test device and evaluate the potential for replacement of RCPT with the Wenner resistivity. This research program consists of the determination of RCPT values, water sorptivity coefficients and electrical resistivities (bulk and surface) of nine concrete mixtures. In addition, the development of the Wenner probe instrument was studied. As well, correlations between resistivity and ASTM C1202 and C1585 are provided followed by technical recommendations for improving the Wenner test.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The durability of concrete structures is the result of protective action of concrete over the rebar. When the passivation of steel ceases to exist the structure becomes vulnerable to the phenomenon of corrosion, which spread after start is largely controlled by the electrical resistivity of concrete. Another important factor in the durability of concrete structures is the absorption, which is one of the properties governing the transport of ions inside the concrete. This study aimed to evaluate the electrical resistivity and capillary absorption of concrete that have undergone surface treatment: a monolithic polymeric mortar applied in a layer of 4mm, and a pore blocker with a single coat and a pore blocker with a double coat. The concrete surface subjected to treatment were made with three types of cement,CP IV-32, CP II-F 32 and CP V and levels of compressive strength of 15MPa, 20MPa and 25MPa. The electrical resistivity was measured by the method of four electrodes and capillary absorption by the method NBR 9779. Treatment with the pore blocker with a double coat was more effective in reducing capillary absorption than a pore blocker with a single coat for the three types of cement, but the best results were obtained using the polymer mortar. In this work the pozzolanic effect present on cement CP IV became more clear in the result of electrical resistivity for all treatment studied. The different behavior of the electrical resistivity of concrete with cement CP IV in relation to others, CPII F and CP V, is justified by changes in the microstructure of the paste, pore refinement and composition of pore solution. In addition to this, when compared to concrete made with CP V, the lower relations/binder of CP IV to obtain the compressive strengh levels investigated, fck = 15 Mpa , 20Mpa and 25Mpa. Even the reference concrete without surface treatment showed values of resistivity well above the actual reference compounds with CP II-F and CP V and also subjected to surface treatment. / A durabilidade das estruturas de concreto armado é resultado da ação protetora do concreto sobre a armadura. Quando a passivação do aço deixa de existir a estrutura torna-se vulnerável ao fenômeno da corrosão, cuja propagação, após iniciada é essencialmente controlada pela resistividade elétrica do concreto. Outro fator importante na durabilidade das estruturas do concreto é a absorção capilar, a qual é uma das propriedades que regem o transporte de íons no interior do concreto. O presente estudo teve por objetivo avaliar a resistividade elétrica e a absorção capilar em concretos que foram submetidos a tratamento superficial: uma argamassa polimérica monocomponente aplicada em camada de 4mm, e um produto obturador dos poros aplicado em uma e duas demãos. Os concretos submetidos ao tratamento superficial foram produzidos com três tipos de cimento, CP IV 32, CP II F 32 e CP V, e para os níveis de resistência à compressão de 15MPa, 20MPa e 25MPa. A resistividade elétrica foi medida pelo método dos quatros eletrodos e a absorção capilar segundo o método NBR 9779. O tratamento com o produto obturador dos poros em dupla demão mostrou-se mais efetivo na redução da absorção capilar do que o tratamento com uma demão para os três tipos de cimento, contudo, os melhores resultados foram obtidos com o uso da argamassa polimérica. Neste trabalho o efeito pozolânico presente no cimento CP IV ficou claro nos resultados de resistividade elétrica para todos os tratamentos estudados. Este comportamento diferenciado do CP IV em relação aos demais, CP II F e CP V, se justifica pelas alterações na microestrutura da pasta, refinamento dos poros e composição da solução dos poros. Acresce a isto, quando comparado aos concretos produzidos com CP V, as menores relações a/agl do CP IV para obtenção dos níveis de resistência à compressão investigados. Mesmo o concreto de referência sem tratamento superficial apresentou valores de resistividade elétrica muito superiores aos concretos de referência compostos com CP II F e CP V e também submetidos a tratamento superficial.

Submitted by Marcos Wanderley (marcos.wanderley@ufcg.edu.br) on 2018-08-02T19:11:43Z No. of bitstreams: 1 FELIPE DE BRITO LEAL - DISSERTAÇÃO(PPGEPM) 2018.pdf: 2534276 bytes, checksum: 3031c6788b6f03fbf0bf11a8f8afde4a (MD5) / Made available in DSpace on 2018-08-02T19:11:43Z (GMT). No. of bitstreams: 1 FELIPE DE BRITO LEAL - DISSERTAÇÃO(PPGEPM) 2018.pdf: 2534276 bytes, checksum: 3031c6788b6f03fbf0bf11a8f8afde4a (MD5) Previous issue date: 2018-02-26 / Capes / As propriedades físicas das rochas têm grande importância no planejamento, execução e custo dos projetos de engenharia de reservatório. O objetivo desta pesquisa é avaliar as propriedades elétricas das rochas a partir da análise de imagens de microtomografia de raios x, além de buscar uma correlação com as demais propriedades petrofísicas. Para o desenvolvimento dessa pesquisa foram selecionadas 16 amostras de carbonatos, sendo 12 calcários e 4 dolomitos, de três diferentes bacias (Araripe, Potiguar e Sergipe –Alagoas). Na presente pesquisa, a partir de imagens microtomográficas e utilização do software Avizo Fire, foram obtidos dados petrofísicos computacionais, além da geração de uma malha tridimensional para simulação de propriedades elétricas das amostras, sendo esta simulação realizada no software Comsol Multiphysics. Utilizando algumas propriedades obtidas na pesquisa e aplicando a lei de Archie, foi possível avaliar a molhabilidade das amostras. Os valores de densidade total possuem boa relação com a porosidade e o fluido saturante. Na relação entre a porosidade e a permeabilidade, chama atenção as amostras com valores de porosidade semelhantes, mas com permeabilidades bem diferentes. Este fator pode ser explicado pela baixa conectividade dos poros, baixando a permeabilidade. Ao comparar as porosidades obtidas por ensaios convencionais e computacionais, em alguns casos, foram observados diferentes valores para a mesma amostra. Este fato pode ser explicado pela escolha do subvolume da amostra computacional e o fato do ensaio convencional medir apenas a porosidade efetiva. Ainda observando os resultados obtidos nos ensaios realizados, foi verificado que a porosidade pode apresentar uma relação inversamente proporcional com a tortuosidade. A resistividade demonstrou forte relação com o tipo da rocha, onde, amostras de calcários possuem maior resistividade do que as amostras de dolomitos. A conectividade dos poros de uma rocha pode ser determinante na influência da porosidade sobre a resistividade dessa rocha, já que poros isolados não apresentam grande influência na condutividade elétrica de uma rocha. Ao avaliar a molhabilidade, foram identificadas sete amostras molháveis à água, três com molhabilidade neutra ou intermediária e seis preferencialmente molháveis à óleo. A molhabilidade das amostras apresentou relação direta com as bacias que as mesmas se localizavam. / The physical properties of the rocks have great importance in the planning, execution and cost of the reservoir engineering projects. The objective of this research is to evaluate the electrical properties of the rocks from the analysis of x-ray microtomography images, in addition to searching for a correlation with the other petrophysical properties. For the development of this research, 16 samples of carbonates, 12 limestone and 4 dolomites, were selected from three different basins (Araripe, Potiguar and Sergipe - Alagoas). In this research, from the microtomographic images and the use of Avizo Fire software, computational petrophysical data were obtained, as well as the generation of a three - dimensional mesh to simulate the electrical properties of the samples, being this simulation carried out in Comsol Multiphysics software. Using some properties obtained in the research and applying the Archie’s law, it was possible to evaluate the wettability of the samples. The values of total density also have good relation with the porosity and saturating fluid. When analyzing the relationship between porosity and permeability, can be highlighted the samples with similar porosity values, but with very different permeabilities. This factor can be explained by the low connectivity of the pores, resulting in low permeability. When comparing the porosities obtained by conventional and computational tests, in some cases different values were observed for the same sample. This can be explained by the subjective choice of the subvolume of the computational sample and the fact that the conventional test only measures the effective porosity. Still observing the results of the tests, it was verified that the porosity may present an inversely proportional relation with the tortuosity. The resistivity showed a strong relationship with the type of rock, where calcareous samples have higher resistivity than dolomite samples. The pore connectivity of a rock can be determinant in the influence of the porosity on the resistivity of this rock, since isolated pores do not have great influence on the electrical conductivity of a rock. When assessing the wettability, seven water-wettable samples, three with neutral or intermediate wettability, and six preferentially oil-wettable were identified. The wettability of the samples was directly related to the basins that were located.

Le potentiel des procédés d’impression dans les applications électroniques sur des supports en céramique a été démontré dans ce travail. Plusieurs techniques d’impression ont été étudiées : sérigraphie, flexographie, héliogravure et jet d’encre. Les propriétés de surface de plusieurs types de céramique ont été caractérisées avant et après frittage : taille des pores, rugosité et énergie de surface. Ces analyses ont permis de sélectionner les matières premières des encres les mieux adaptées à ces supports, ainsi qu’aux procédés d’impression considérés. Des formulations aqueuses à base de particules d’argent ont été privilégiées. Les propriétés de ces encres, rhéologie et tension de surface, ont été analysées et leurs effets sur la qualité des lignes imprimées (largeur, épaisseur et rugosité) ont été évalués. Après impression, les motifs ont été frittés. Des résistivités proches de celle de l’argent ont été obtenues (2 à 12x10-8 Ohm.m). L’originalité de ce travail réside notamment dans l’utilisation d’encres sérigraphiques à base d’eau et l’impression d’encres flexographiques sur des supports en céramique. Cette étude ouvre donc des perspectives pour l’industrialisation et la production de masse de composants électroniques sur supports céramiques souples. / This work demonstrates the printing processes potential for manufacturing ceramic based electronic devices. Several printing techniques were studied: screen printing, flexography, rotogravure and inkjet. Ceramic tapes surface properties were characterised: surface pore size, roughness and surface energy. These analyses allowed the selection of the inks raw materials adapted to the substrates and the printing processes. Water-based silver inks were formulated. Inks properties, rheology and surface tension, were analysed and their effect on line properties was investigated. Printed substrates were afterwards sintered. Resistivity values close to that of bulk silver were reached (2 to 12x10-8 Ohm.m). These work novelties are mainly the formulation of water-based environmentally friendly screen printing pastes and the flexography printing of silver inks onto ceramic substrates. This study offers new perspectives for the industrialisation and the mass production of electronic components on flexible ceramic substrates.

Southern Vancouver Island lies on the forearc of the Cascadia subduction zone, north of a concave bend in the plate boundary centred around the Olympic Mountains. The bend in the margin coincides with a significant decrease in northward-directed trench-parallel forearc migration, and a network of active crustal faults in the Puget Lowland east of the Olympic Mountains accommodates permanent north-south shortening and transpression. The nature of forearc deformation on southern Vancouver Island is less well constrained, due in part to the unknown extent and kinematics of active crustal faulting. Recent work has shown that a brittle fault zone associated with the Eocene terrane-bounding Leech River fault has produced at least two surface-rupturing earthquakes in the late Quaternary. I use LiDAR-derived topographic data, slip-sense indicator analysis of slickenlines on fault planes, electrical resistivity tomography (ERT), and ground-penetrating radar (GPR) to investigate the geometry, kinematics, and Quaternary activity along the eastern half of the active, brittle Leech River fault zone. My mapping reveals a complex, near-vertical zone up to 1 km wide and 25 km long that exhibits many characteristics of a strike-slip fault. Displaced Quaternary deposits are observed directly at two sites in the western 8 km of the study area, and inferred through geophysical imagery, topographic data, and liquefaction features to extend to the eastern terrestrial extent of the fault zone towards previously mapped active faults in the Juan de Fuca Strait and the Darrington-Devil’s Mountain fault zone in western Washington. I use fault kinematics and geometry to show that the eastern Leech River fault zone has been reactivated as a right-lateral strike-slip fault that accommodates forearc deformation within the modern stress field north of the Olympic Mountains. / Graduate / 2018-12-01

Realizar a modelagem de um aqüífero não é tarefa fácil. Em se tratando de um sistema aqüífero, a empreitada se torna ainda mais complexa. Neste trabalho, alguns dos parâmetros importantes para esse fim foram estimados a partir de simulações. Na região de estudo, existem poços tubulares que, em sua maioria, não foram perfurados somente na Formação Adamantina, mas também na Formação Serra Geral. Tal configuração conduziu à formulação de dois conjuntos de cenários a partir dos quais foi possível estimar valores de condutividade hidráulica para as duas formações. Com essa estimativa conseguiu-se também simular testes de bombeamento, seus respectivos cones de rebaixamento, bem como a interferência causada entre cones de rebaixamento. Com essa abordagem foi possível estimar o quanto um poço em funcionamento pode influenciar no nível estático de um vizinho. A contribuição da geofísica está no uso da eletroresistividade. Foram executadas 23 Sondagens Elétricas Verticais (SEV), das quais dezenove são SEV´s curtas (AB/2 500m) e quatro, longas (AB/2 1500), que forneceram informações sobre a espessura saturada do arenito e posição do topo do basalto, especialmente na região com poucos poços. Também foram realizados quatro Caminhamentos Elétricos (CE) no estudo de possíveis estruturas. Unindo os resultados da modelagem (simulação) e da geofísica, pôde-se relacionar os parâmetros hidrogeológicos e geoelétricos. Embora o conjunto de dados para a região não tenha sido o ideal, a metodologia se mostrou adequada e os resultados bastante razoáveis. Deste modo, foi possível a determinação de parâmetros hidrogeológicos em subsuperfície através de parâmetros geoelétricos medidos em superfície. / To perform the aquifer modelling is not an easy task. In the case of an aquifer system, the work becomes even more complex. In this work, some of important parameters for this purpose have been estimated from simulations. In the study area, there are wells that in most cases were not only drilled in Adamantina Formation but also in Serra Geral Formation. This configuration led to the formulation of two sets of scenarios from which it was possible to estimate values for hydraulic conductivity of these formations. With this estimate it could also simulate pumping tests, their cones of depression as well as the interference caused between cones of depression. With this approach it was possible to estimate how much a operating well can influence static level of a neighbour one. Geophysics contribution is in the use of electrical resistivity. Twenty-three Vertical Electrical Soundings (VES) were performed, nineteen of them are short (AB/2 500m), that provided information about the saturated thickness of sandstone as well as top of basalt, especially in the region with few wells, and four are long (AB/2 1500) VESs. Four electrical profiling (EP) were also carried out to study possible structures. Joining modelling (simulation) and geophysics results, it could be related hydrogeological and geoelectrical parameters. Although dataset for region was not the ideal, methodology was satisfactory, and results quite reasonable. Thus, it was possible to determine hydrogeological parameters in subsurface through measured geoelectrical parameters in surface.