Seismic response of a structure is influenced by the inertial interaction between structure and deformable medium, on which the structure rests, due to flexibility and energy dissipation capability of the surrounding soil. The inertial interaction analyses can be performed by utilizing simplified soil-structure interaction (SSI) analyses methods. In literature, it is noted that varying soil conditions and foundation types can be modeled by using these SSI approaches with springdashpot couples having certain stiffness and damping. In this study, the seismic response of superstructure obtained by using simplified SSI methods is compared with those of the fixed base systems. For this purpose, single and multi degree of freedom structural systems are modeled with both spring&ndash / dashpot couple and fixed base models. Each system is analyzed for varying structural and soil stiffness conditions under the excitation of three different seismic records. Next, the total base shear acting on the structural system and internal forces of load bearing members are investigated to observe the inertial interaction and foundation uplift effects on the superstructure. It is also aimed to examine the compatibility of the simplified SSI approaches utilized in the analyses. It is concluded that the structural and soil stiffness parameters are the most influential parameters that affect seismic structural response. Structures becomemore sensitive to varying soil properties as the structural stiffness increases. On the other hand, decreasing soil stiffness also increases the sensitivity of the structure to the seismic excitation. Calculated values of total base shear and internal member forces revealed that the inertial interaction might be detrimental for the superstructure. Contrary to general belief, the fixed base approach does not always yield to the results, which are on the safe side. Considering the analysis results, it is concluded that SSI analysis is very useful for more precise and economical design for the seismic behavior.

This thesis investigates the feasibility of using fluid flow as a deformable model for segmenting vessels in 2D and 3D medical images. Exploiting fluid flow in vessel segmentation is biologically plausible since vessels naturally provide the medium for blood transportation. Fluid flow can be used as a basis for powerful vessel segmentation because streaming fluid regions can merge and split providing topological adaptivity. In addition, the fluid can also flow through small gaps formed by imaging artifacts building connections between disconnected areas. In our study, due to their simplicity, parallelism, and low computational cost compared to other fluid simulation methods, linearized shallow water equations (LSWE) are used. The method developed herein is validated using synthetic data sets, two clinical datasets, and publicly available simulated datasets which contain Magnetic Resonance Angiography (MRA) images, Magnetic Resonance Venography (MRV) images and retinal angiography images. Depending on image size, one to two order of magnitude speed ups are obtained with developed parallel implementation using Nvidia Compute Unified Device Architecture (CUDA) compared to single-core and multicore CPU implementation.

Analytical solutions for the linear and nonlinear shallow-water wave equations are developed for evolution and runup of tsunamis &ndash / long waves&ndash / over one- and two-dimensional bathymetries. In one-dimensional case, the nonlinear equations are solved for a plane beach using the hodograph transformation with eigenfunction expansion or integral transform methods under different initial conditions, i.e., earthquake-generated waves, wind set-down relaxation, and landslide-generated waves. In two-dimensional case, the linear shallow-water wave equation is solved for a flat ocean bottom for initial waves having finite-crest length. Analytical verification of source focusing is presented. The role of focusing in unexpectedly high tsunami runup observations for the 17 July 1998 Papua New Guinea and 17 July 2006 Java Island, Indonesia tsunamis are investigated. Analytical models developed here can serve as benchmark solutions for numerical studies.

<p>A new shallow junction formation process, based on selective silicon etching followed by selective growth of in situ B-doped SiGe, is presented. The approach is advantageous compared to conventional ion implantation followed by thermal activation, because perfectly abrupt, low resistivity junctions of arbitrary depth can be obtained. In B-doped SiGe layers, the active doping concentration can exceed the solid solubility in silicon because of strain compensation. In addition, the compressive strain induced in the Si channel can improve drivability through increased hole mobility. The process is integrated by performing the selective etching and the selective SiGe growth in the same reactor. The main advantage of this is that the delicate gate oxide is preserved. The silicon etching process (based on HCl) is shown to be highly selective over SiO₂ and anisotropic, exhibiting the densely packed (100), (311) and (111) surfaces. It was found that the process temperature should be confined between 800 ºC, where etch pits occur, and 1000 ºC, where the masking oxide is attacked. B-doped SiGe layers with a resistivity of 5×10-⁴ Ωcm were obtained. Well-behaved pMOS transistors are presented, yet with low layer quality. Therefore integration issues related to the epitaxial growth, such as selectivity, loading effect, pile-up and defect generation, were investigated. Surface damage originating from reactive-ion etching of the sidewall spacer and nitride residues from LOCOS formation were found to degrade the quality of the SiGe layer. Various remedies are discussed. Nevertheless, high-quality selective epitaxial growth could not be achieved with a doping concentration in the 1021 cm-3 range. The maximum doping level resulting in a high-quality layer, with the loading effect taken into account, was 6×10²⁰cm-³. After this careful process optimization, a high-quality layer was obtained in the recessed areas. Finally, Ni mono-germanosilicide was investigated as a material for contact formation to the epitaxial SiGe layers in the recessed source and drain areas. The formation temperature is 550 ºC and it is stable up to 700 ºC. The observation of a recessed step and lateral growth of the silicide led to a detailed treatment of the contact resistivity of the NiSi₀.₈Ge_0.2/Si_0.8Ge_0.2 interface using 2-D as well as 3-D modeling. Different values were obtained for square shaped and rounded contacts, 5.0x10^-8 Ωcm² and 1.4x10^-7 Ωcm², respectively.</p>

Recent failures and severe corrosion distress of post-tensioned (PT) bridges in Florida have revealed corrosion of the 7-wire strands in tendons. Post-tensioned duct assemblies are fitted with multiple 7-wire steel strands and ducts are subsequently filled with grout. During construction, the length of time from the moment in which the strands have been inserted into the ducts, until the ducts are grouted, is referred to as the `ungrouted' period. During this phase, the steel strands are vulnerable to corrosion and consequently the length of this period is restricted (typically to 7 days) by construction guidelines. This investigation focuses on determining the extent of corrosion that may take place during that period, but limited to strands that were in the unstressed condition. Visual inspections and tensile testing were used to identify trends in corrosion development. Corrosion induced cracking mechanisms were also investigated via wire bending and metallographic cross section evaluation. Corrosion damage on unstressed strands during ungrouted periods of durations in the order of those otherwise currently prescribed did not appear to seriously degrade mechanical performance as measured by standardized tests. However the presence of stress in the ungrouted period, as is normally the case, may activate other mechanisms (e.g., EAC) that require further investigation. As expected in the unstressed condition, no evidence of transverse cracking was observed.

In this dissertation, the framework is being developed for a new method to predict the settlements of shallow foundations on granular soil based on field seismic and laboratory dynamic tests. The new method combines small-strain seismic measurements in the field with nonlinear measurements in the field and/or in the laboratory. The small-strain shear modulus (Gmax ) of granular soil and the stress dependency of Gmax is determined from the shear wave velocity measurements in the field. Normalized shear modulus (G/Gmax ) versus log shear strain(log [gamma]) curves are determined from field or laboratory measurements or from empirical relationships. The G/Gmax -- log [gamma] curves and Gmax values are combined to determine the shear stress-shear strain response of granular soil starting from strains of 0.0001% up to 0.2-0.5%. The shear stress-shear strain responses at strains beyond 1.0-2.0 % are evaluated by adjusting the normalized shear modulus curves to larger-strain triaxial test data. A user defined soil model (MoDaMP) combines these relationships and incorporates the effect of increasing confining pressure during foundation loading. The MoDaMP is implemented in a finite element program, PLAXIS, via a subroutine. Measured settlements from load-settlement tests at three different sites where field seismic and laboratory dynamic measurements are available, are compared with the predicted settlements using MoDaMP. Predictions with MoDaMP are also compared with predictions with two commonly used methods based on Standard Penetration and Cone Penetration tests. The comparison of the predicted settlements with the measured settlements show that the new method developed in this research works well in working stress ranges. The capability of the new method has significant benefits in hard-to-sample soils such as in large-grained soils with cobbles and cemented soils where conventional penetration test methods fail to capture the behavior of the soil. The new method is an effective-stress analysis which has applicability to slower-draining soils such as plastic silts and clays. / text

Reproducing moisture retention behavior of the upper and lower vadose zone in shallow water table settings provides unique challenges for integrated (combined surface and groundwater) hydrological models. Field studies indicate that moisture retention in shallow water table settings is highly variably affected by antecedent state and air entrapment. The theory and vertical behavior of a recently developed integrated surface and groundwater model (IHM) is examined through comparisons to collected field data in West-Central Florida. The objectives of this study were to (1) Identify important considerations and behavior of the vadose zone for reproducing runoff, ET and recharge in shallow water table settings; (2) Develop a conceptual model that describes vertical soil moisture behavior while allowing for field scale variability; (3) Test the model against observations of the vertical processes; (4) Investigate the sensitivity of model parameters on model vs. observed vertical behavior, and (5) offer recommendations for improvements and parameterization for regional model application. Rigorous testing was made to better understand the robustness and/or limitations of the methodology of the IHM for upper and lower vadose zone. The results are also generally applicable and useful to the upper zone and lower zone conceptualization and parameterization of stand alone HSPF and perhaps other surface water models. Simulation results indicate IHM is capable of providing reasonable predictions of infiltration, depth to water table response, ET distributions from the upper soil, lower soil and water table, and recharge while incorporating field scale variability of soil and land cover properties.

The two-dimensional depth-averaged shallow water equations have attracted considerable attentions as a practical way to solve flows with free surface. Compared to three-dimensional Navier-Stokes equations, the shallow water equations give essentially the same results at much lower cost. Solving the shallow water equations by the Godunov-type finite volume method is a newly emerging area. The Godunov-type finite volume method is good at capturing the discontinuous fronts in numerical solutions. This makes the method suitable for solving the system of shallow water equations. In this dissertation, both the shallow water equations and the Godunov-type finite volume method are described in detail. A new surface flow routing method is proposed in the dissertation. The method does not limit the shallow water equations to open channels but extends the shallow water equations to the whole domain. Results show that the new routing method is a promising method for prediction of watershed runoff. The method is also applied to turbulence modeling of free surface flow. The κ - ε turbulence model is incorporated into the system of shallow water equations. The outcomes prove that the turbulence modeling is necessary for calculation of free surface flow. At last part of the dissertation, a total load sediment transport model is described and the model is tested against 1D and 2D laboratory experiments. In summary, the proposed numerical method shows good potential in solving free surface flow problems. And future development will be focusing on river meandering simulation, non-equilibrium sediment transport and surface flow - subsurface flow interaction.

Uppsatsen tar upp Arne Naess djupekologi. Den undersöker djupekologins struktur och vilka krav som ställs på en teori för att den skall vara en djupekologi. Uppsatsen tar även upp skillnader mellan djupekologi och grundekologi på en praktisk nivå. Uppsatsen behandlar Warwick Fox kritik rörande djupet i djupekologin och Arne Naess svar på den kritiken. Författaren till uppsatsen finner att Fox kritik inte är helt träffande och att Naess svar på kritiken är för svag. / This paper discusses Arne Naess’ theory of deep ecology. It investigates the structure of deep ecology and what conditions a theory has to fulfil to be a deep ecology. The paper demonstrates differences between deep ecology and shallow ecology on a practical level. The paper presents a criticism put forward by Warwick Fox which focuses on the deepness of deep ecology, and an answer from Arne Naess on this criticism. The author of this paper finds Fox’ criticism not quite convincing, and that Naess’ answer is too weak.

The emphasis of this dissertation is on using numerical and plasticity based methods to study two main areas of offshore geotechnics. The first part of this dissertation focuses on the undrained behavior of deeply embedded anchor plates under combined shear and torsion. Plate anchors are increasingly being used instead of typical foundation systems to anchor offshore floating platforms to sustain uplift operating forces. However extreme loading cases would create general loading conditions involving six degrees of freedom. The focus of my research was to evaluate the bearing capacity of plate anchors under two-way horizontal and torsional loading and to study the decreasing effect of torsional moment on the horizontal bearing capacity of these foundations. The study takes advantage of several approaches: Numerical simulation (two and three dimensional finite element analysis) Evaluating and modification of the available plasticity solutions Developing equations for three degree-of-freedom yield locus surfaces The same methodology is applied to evaluate the response of shallow foundations for subsea infrastructure subjected to significant eccentric horizontal loads. The second part of this study focuses on offshore geohazards. Coastal communities and the offshore industry can be impacted directly by geohazards, such as submarine slope failures, or by tsunamis generated by the failed mass movements. This study aims at evaluating the triggering mechanisms of submarine landslide under cyclic wave and earthquake loading. A simple effective stress elasto-plastic model with a minimal number of parameters accounting for monotonic and cyclic response of fine-grained material is developed. The new constitutive soil model could be used to simulate case histories and conduct parametric study to evaluate the effect of slope inclination angle, the earthquake loading with different PGA, frequency content, and duration, as well as various deposition rates to simulate different over pressure levels. This study will generate more insight on the static and cyclic behavior of submarine slopes and influencing factors on their triggering mechanisms using more comprehensive and realistic modeling tools. Several objectives are defined: Developing an appropriate constitutive formulation, Evaluating the constitutive model and material parameters for available databases.