Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"stress regime"”.
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LABORATORY INVESTIGATION OF COAL PERMEABILITY UNDER REPLICATED IN SITU STRESS REGIME
… parameter impacted by changes in effective stress and desorption-induced "matrix shrinkage". Most commonly-used theoretical models developed to predict CBM production as a result of permeability changes are based on the assumption that the deformation of a depleting coalbed is limited to the …
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REGIONAL STRESS REGIME STUDY OF EAST TEXAS BASED ON ORIENTATION OF FRACTURES IN THE WECHES FORMATION
… was used to infer information about the regional stress regime based on the direction of maximum/minimum horizontal stresses (SHmax / SHmin) that formed the fractures. This is based on the principle that systematic, steeply dipping, mode I joints propagate in the direction of SHmax and normal to …
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Bias temperature instability (BTI) in GaN MOSFETs
… instability under high voltage and temperature stress, sometimes referred to as bias-temperature instability (BTI), is a serious concern. The physical mechanisms responsible for BTI in GaN MIS-HEMT are not well understood. This is mainly because of the complex gate stack with multiple layers and …
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Fracture reactivation and gold mineralization in the epithermal environment : structural evolution of the Endeavour 42 gold deposit, New South Wales, Australia
… over a period spanning two distinct structural regimes. Early gold-bearing veins are steeply dipping and interpreted as forming coevally along two sets of faults and dykes within a tensional stress regime. High grade fault-hosted, hydrothermally cemented breccia intervals are included temporally …
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Understanding Time-Variant Stress-Strain in Turkey: A Numerical Modeling Approach
… events and tectonic influences affect the stress regime of the NAFZ and how these stress changes affect the probability of future rupture along any unbroken segments of the fault zone using a two dimensional finite element modeling program. In this study, stress changes due to an earthquake …
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Analysis and interpretation of compressional (P-wave) and shear (SH-wave) reflection seismic and geologic data over the Bane Dome, Giles County, Virginia
… that time may now be reactivated by the present stress regime, causing earthquake activity in this area. Interpretation of the seismic data supports a duplex structure proposed for the Paleozoic rocks of the Bane Dome Complex within the Narrows thrust sheet of southwestern Virginia.
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Source Parameters and Tectonic Setting of the 2017 St. Elias Earthquake Sequence near the Southern Terminus of the Eastern Denali Fault, Northwestern Canada
… along two previously unmapped fault structures. Stress inversion indicates that the maximum principal stress axis is oriented almost perpendicular to the EDF, suggesting that the fault system is not well oriented for strike-slip in the contemporary stress field. Coulomb stress analysis indicates …
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Geometric and hydrodynamic modelling of fluid-structural relationships in the southeastern Athabasca Basin, Saskatchewan, Canada, with implications for uranium ore genesis
… in relation to deformation in a compressional stress regime indicates that the fluid flow pattern is sensitive to the degree of bulk shortening. At a low bulk shortening stage, fluid is driven up along the fault zone into the sandstone in the basin, whereas at a relatively high degree of bulk …
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Simulation and optimisation of hydraulic fracturing and flowback in unconventional reservoirs: A case study in the Cooper Basin, South Australia
… in the Cooper Basin: 1. The complexity of the stress regime is believed to be the main reason for the failure in some hydraulic fracturing operations in the Cooper Basin, as the stress can alternate between strike-slip, reverse and normal regimes along the wellbore. To better understand the …
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Robust optimization for portfolio risk : a ravisit of worst-case risk management procedures after Basel III award.
… encourage us to construct a forward-looking stress test procedure based on robust portfolio optimization under regime switches. For this purpose, the Markov chain process is embedded into robust optimization procedure in order to stress regime transition matrix. In addition, assets returns, …
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Numerical simulation of selected geologic processes based on Discrete Element Method
… of Ordos Block (China) under present tectonic stress regime based on Universal Distinct Element Code (UDEC). A scale-independent modeling approach based on PFC2D has been established to simulate the development of pull-apart basins. The micro-scale PFC models are used to investigate crack …
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Luminescence studies of the excitonic system in germanium: Phase properties and transport
… (EHL) phase as a function of <111>-uniaxial stress. The application of stress along a <111> axis greatly reduces the degeneracy of the conduction and valence bands, thereby reducing the stability of the EHL. This thesis reports the first observation of the EHL in the high-stress limit (u > 70 …
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Geomechanical Stability Analysis for Co2 Sequestration in Carbonate Formation
… Williston Basin were investigated. The in-situ stress regime of the Williston Basin was estimated as a mixture of normal and strike-slip faulting regimes, in favor of a vertical or sub-vertical fracture development pattern, which is negative to the CO2 sequestration. However, as the basin is not …
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The initiation and evolution of ignimbrite faults, Gran Canaria, Spain
… on shear faults in overall compressional stress regimes. Dilational structures have been examined in compressional settings e.g. overlapping faults generating extensional oversteps, or in normal faults cutting mechanical layered stratigraphy. Previous work has shown the affect mechanical …
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GEOCHRONOLOGY, GEOCHEMISTRY, AND TECTONIC CHARACTERIZATION OF QUATERNARY LARGE-VOLUME TRAVERTINE DEPOSITS IN THE SOUTHWESTERN UNITED STATES AND THEIR IMPLICATIONS FOR CO2 SEQUESTRATION
… and Arizona occur in an extensional tectonic stress regime on the southeastern Colorado Plateau and along the Rio Grande rift. They accumulated above fault systems during episodes of high hydraulic head in confined aquifers, increased regional volcanic activity, and high input of …
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Putting Lipstick on a PIG: Modeling Pine Island Glacier (PIG) Shear Margin Collapse with Compressive Arch Failure and Observations
… to increase in thickness to a point at which the stresses within the ice would exceed the tensile yield strength without the compression provided by buttressing. Following the Compressive Arch Theory proposed by \textcite{doake_breakup_1998}, we hypothesize that when a calving event decouples the …
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Optimizing Pillar Design for Improved Stability and Enhanced Production in Underground Stone Mines
… along with characterizing the redistributed stress regime by imitating the excavation sequence. The results from pillar-scale and local-scale analyses are converged to optimize pillar design on a global scale and estimate the feasibility of secondary recovery in stone mines with a dominating …
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Anisotropy, focal mechanisms, and state of stress in an oilfield : passive seismic monitoring in Oman
Knowledge of the spatial characteristics of stress and fractures in reservoirs is important for optimising production and injection processes. Serni-permanent passive microseismic monitoring is being conducted in the Yibal field, Oman, to better understand reservoir geomechanics. The network …
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Mechanical behavior of individual type I collagen fibrils
… ratio of 1.3±0.06, and initial stiffness of the stress (σ) vs. stretch ratio (λ) curves, E1 = 5.7±2.3 GPa. These results depended on fibril diameter: fibrils with larger diameters showed increased maximum stretch ratio, λmax, and decreased E1 and decreased stiffness, E2, of the softening regime …
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Study of induced seismicity for reservoir characterization
… other properties of the reservoirs, such as stress regime and velocity structure (Chapters 2, 3, 4); 2) understanding the fractures in reservoirs as seismic scatterers (Chapter 5). First, I introduce a new method to determine the source mechanisms of the induced earthquakes by incorporating …
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