Subduction of an oceanic plate under the Pacific margin of South America has heen prevalent since Jurassic times. Magmatic and deformation centres have migrated eastward since suhduction began. Northern Chile houses two north-south trench linked strike-slip fault systems, the Atacama Fault Zone and the Domeyko Fault System (DFS). The DFS lies within the Chilean Precordillera from 2 10 to 28°S. Lateral movement began on the DFS in the Eocene. The DFS can be divided into three segments which have apparently undergone differing deformation histories. This study has focused on the central segment of the DFS, to determine fault kinematics and to establish a relative chronology of deformation. Observations have been made in more detail than previous investigations and have heen used to infer the deformation history . Shallow level faulting has resulted in heavily fractured zones with occasional slickenline surfaces. It is difficult to infer kinematics of faulting from these. Much effort has been expended in developing techniques to analyse fracture patterns associated with brittle faulting under conditions of plane strain, simple shear. A novel approach of analysing the shapes of clasts of rock defined by secondary fractures within a fault zone has been used. The clasts approximate ellipses when viewed in 2 dimensions. Combining ellipse orientation and aspect ratio from mutually perpendicular sections through the fault zone allowed calculation of an ellipsoid representative of the clasts of rock in 3 dimensions. Independent determination of the fault kinematics using stratigraphic relationships across the fault, fracture distribution, incremental strain axes and palaeomagnetic analysis has all owed evaluation of the new technique. The shapes of rock clasts are found to be related to the kinematics of the fault system. Up to a critical stage of development of the fault zone the axes of the rock clasts parallel the slip direction, intermediate strain axis and pole to the boundary faults. Which rock clast axis parallels which structural feature depends upon the spacing and curvature of fractures and stage of development of the fault zone. Analysis of the shapcs or rock clasts defined by fractures can avoid bias of the data set towards thicker fractures or against irregular fractures, which can occur when measuring fracture orientations directly. The degree of development of the fault zone varies laterally along the fault over short distances. This causes the shape.: fabric of the rock clasts to change, so predictions of connectivity within a fault zone are limited. The history of the central segment of the DFS determined from this study is found to occur with earlier workers. The complementary deformation histories produced from two scales of ohservation verifies the reliability of the chronology. Lateral movements along the DFS are thought to begin in the Eocene with a sinistral transpressive event which occurred along all three segments of the DFS. En echelon folds, east and west verging thrusts and clockwise rotations associated with sinistral faulting along the master fault of the segment are documented. Later, in the Oligocene, dextral faulting occurred. large clockwise palaeomagnetic rotations, determined from Palaeozoic samples beside the master fault, indicate sinistral displacements have been larger than dextral disp acements. It is inferred that only one episode of large lateral transport occurred. This is the Eocene sinistral event. Normal faulting associated with sinistral displ acements along the western side of the system are documented. This later sinistral faulting has not been documented before in the central segment of the DFS. After Oligocene age dextral faulting, the three segments of the DFS underwent separate deformation histories, as the main Andean deformation foci had moved eastward.

Patch repairs are sometimes considered to be capable of contributing to the resisting of externally applied load when the repairs are applied to deteriorated concrete structural members, particularly when the repair is subj ected to compression. However, it is generally known that many patch repair materials shrink and creep significantly relative to the concrete substrate. This thesis presents an experimental and numerical study of the contribution of patch repairs to load carrying in reinforced concrete columns, its quantification and the effect of shrinkage and creep. Twelve reinforced concrete columns were cast with a cavity located halfway up one side of the column. Two control columns were cast without a cavity. The parameters varied in the experimental testing were the depth of the repair cavity, type of repair material (one polymeric and the other polymer-modified), and whether the repaired columns were monitored under load or without being loaded. Test results prior to repair indicate that the loss of concrete from the column induces bending in the loaded column. Both the polymer-modified and polymeric mortar contributed to the column's resistance of the applied load in the short term, but in the long term the contribution of the polymer-modified mortar decreased substantially while that of the polymeric mortar was sustained. Repaired columns which were monitored with no load showed that shrinkage of the polymer-modified mortar can induce bending in the repaired column; this bending increased with cavity depth. Bending strain distributions in the repaired area are close to a straight line, particularly for columns monitored under load. The finite element numerical simulations showed good qualitative agreement with the test results. The analyses also indicated that strain distributions outside but close to the repaired area are nonlinear. However, predictions of the engineer's theory of bending showed favourable quantitative agreement with the finite element analyses.

Graphene nanostructures directly grown on SiC are appealing for their potential application to nano-scale electronic devices. In particular, epitaxial sidewall graphene nanoribbons have been a promising candidate in ballistic transport and band gap engineering. In this thesis, we study graphene nanoribbons by utilizing both nano-lithography and natural step bunching to control the step morphology of the SiC(0001) surface in order to guide the growth of graphene which initiates at step edges, and study their respective characteristics. With scanning tunneling microscopy and spectroscopy (STM/STS), we explore the local atomic and electronic structures of the graphene nanoribbons down to atomic scale. It is found that nanoribbon formation depends critically on nanofacet orientation, nanofacet density, and growth conditions. Under some conditions, nanoribbons grow predominantly on the nanofacet. Significant electronic density-of-states features, resolved by STS, are found to depend strongly on proximity to strained graphene near the step edge. Experimental results are compared to Molecular Dynamics simulations to better understand the origin of the discrete electronic states.

Nanoindentation has a high load resolution, depth sensing capabilities, and can be used to characterize the local mechanical behavior in material systems with heterogeneous microstructures. Recently nanoindentation has been used to extract useful stress-strain curves, primarily in hard materials such as metals and ceramics. To apply these indentation stress-strain methods to polymer composites, we have to first develop analysis techniques for materials that exhibit viscoelasticity. In a lot of current research the viscoelastic material properties are extracted after the material has been deformed enough to initiate plasticity and in some cases the time dependence of the deformation is ignored. This doesn’t give an accurate representation of the material properties of the undeformed sample or the local deformation behavior of the material. This dissertation develops analysis protocols to extract stress-strain curves and viscoelastic properties from the load-displacement data generated from spherical nanoindentation on materials exhibiting time-dependent response at room temperature. Once these protocols are developed they can then be applied, in the future, to study viscoelastic and viscoplastic properties of various mesoscale constituents of composite material systems. These new protocols were developed and tested on polymethyl methacrylate, polycarbonate, low-density polyethylene, and the bio-polymer chitosan. The properties extracted were consistent under different conditions and we were able to produce stress-strain curves for different loading rates and different indenter tip sizes. This dissertation demonstrates that a set of protocols can be used to reliably investigate the mechanical properties and deformation behavior of time-dependent materials using nanoindentation.

In this work, a model microbial agent for bioremediation was improved using fermentation and formulation methods. The outcomes of the fermentation work include the development of a new culture medium which increased the cell productivity greater than one order of magnitude. A robust functionality to degrade the herbicide atrazine was expressed. The new medium was scaled-up to a 2L bioreactor. Liquid bacterial culture was not inherently stable and lost viability at both 4°C and 25°C storage. When liquid bacterial culture was formulated by encapsulation in a biopolymer gel and applied to zeolite the transfer of cells from bacterial culture to formulated carrier was highly efficient. No loss of viability was measured from the immobilization process, and the functionality of the agent was retained. The formulated agent expressed an extended shelf life of at least 10 weeks when stored in ambient (25°C) temperature. When the formulation granules were inoculated into sterile soil, viability of the granules was stable and also retained the maximum level of functionality for the full test period of 10 weeks. The soil surrounding the formulation granules was also enumerated. The number of cells in the soil increased after a single inoculation of the formulation and the maximum level of functionality was conveyed from the formulation to the surrounding soil. The formulated inoculant constitutes an improvement for a bioremediation strain to stabilize the agent, produce an extended shelf life at ambient temperatures, and maintain the functionality of a microbe to utilize atrazine. In this thesis we have used a biopolymer formulation in which an inoculum is simply mixed into a gel and applied directly to the surface of the zeolite with no special equipment, drying, temperatures, or secondary re-growth steps required. It is a simple model system consisting of a carrier, and a artificial biofilm. As a technique to produce stable functional inoculants for bioremediation, the work presented here demonstrates an approach that is simple, practical, effective, and robust.

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