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.
Results
Showing 1 to 20 of 26 for “"Spatially Inhomogeneous"”.
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Mesh-free modeling of spatially inhomogeneous aerosols in arbitrary geometries
… simulated with the assumption that they are spatially homogeneous. Making this assumption reduces complexity when compared to spatially inhomogeneous aerosol models. This dissertation investigates using the Direct Simulation Monte Carlo (DSMC) method for spatially inhomogeneous aerosol …
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Ultrafast dynamics in complex molecular solids: Ultrafast imaging of laser ablation of PMMA and theory of mechanical energy flow in ultrahot crystalline naphthalene
… apparatus is constructed and used to investigate spatially inhomogeneous dynamics in laser surface ablation of polymers. Second, time dependent mechanical energy redistribution in ultrahot anharmonic solids composed of organic molecules is studied theoretically.
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Wavefront Engineering and Computational Sensing with Acoustic Metamaterials
… bands. Acoustic wave controlling devices with spatially inhomogeneous or/and anisotropic acoustic properties can be designed with metamaterials. The early versions of acoustic metamaterials generally share several drawbacks that limit their applications: relatively high loss, narrow bandwidth, …
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Magnetorheological fluids for extreme environments : stronger, lighter, hotter
… forces. Finally, the flow of MR fluids in spatially-inhomogeneous magnetic and deformation fields was studied. A slit-flow magnetorheometer was manufactured to measure the bulk MR response of the fluid under non-uniform fields. In order to understand the parameters governing these flows and …
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Light Propagation in Ultracold Atomic Gases
… of a propagating slow Dark Polariton in a spatially inhomogeneous system. The coherently tunable atomic gas acts as a Dynamic Photonic Structure. Applications of this concept concerning wavelength conversion and reshaping of the pulse are also discussed for realistic experimental situations.
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Exploring linear and nonlinear electromagnetic responses in topological materials
… in wavevector. Crucially, we require that our spatially inhomogeneous response theory obeys the conservation of current. In formulating this response theory, we consider two topological material models that are experimentally relevant: the Weyl semimetal and the moiré Chern insulator. We first …
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Controlling non-equilibrium dynamics in lattice gas models
… namely studies of collective responses in spatially inhomogeneous systems. Whereas substantial progress has been made in understanding the origins and the often universal nature of cooperative behavior in systems far from equilibrium, it is still unclear whether it is possible to control …
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Mathematical Analysis on the PEC model for Thixotropic Fluids
… on planar Poiseuille flow. Since the flow is spatially inhomogeneous in this situation, shear bands are observed. The flow is driven by a homogeneous pressure gradient, leading to a variation of stress in the cross-stream direction. In this setting, the flow would yield in different time …
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Radiative feedbacks in tropical organized convection and the Madden-Julian oscillation
… dry the MJO. (4) The LW CRF of the MJO is spatially inhomogeneous, with stronger feedbacks over the tropical Indian ocean and to the northwest of Australia, but weaker feedbacks over the tropical western and central Pacific. The spatial pattern may be determined by the spatial distribution …
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Analysis of Cartesian and projection (K,T)-space sampling patterns when using the partially separable functions model for cardiac perfusion MR imaging
… of the heart when the perfusion is spatially inhomogeneous using the PSF dynamic imaging method. Ten total sampling patterns (five Cartesian and five projection) were analyzed. Overall, the Cartesian sampling patterns provided better reconstructions in terms of image quality, image …
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Investigating the relationship between the superconducting and pseudogap states of the high-temperature superconductor Bi-2201 using scanning tunneling microscopy
… Bi2Sr2CuO6+8 (Tc = 15 K). Initially we find a spatially inhomogeneous gap which smoothly evolves with temperature through Tc. However, from the temperature and spatial dependence of the spectra, we are able to employ a normalization scheme which leads us to uncover a small, spatially …
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Electrostatic effects of inhomogeneous strain in monolayer transition metal dichalcogenides
… optical and electronic properties, and highly inhomogeneous strain distributions in two-dimensional materials can be easily realized, allowing for their properties to be tuned on the nanoscale. This work is primarily focused on transition metal dichalcogenides, which have received much …
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Abstractions, Analysis Techniques, and Synthesis of Scalable Control Strategies for Robot Swarms
… with some modeling and analysis extensions to spatially inhomogeneous systems. The methodology is applied to the design of a swarm task allocation approach that does not rely on inter-robot communication, a reconfigurable manufacturing system, and a cooperative transport strategy for groups of …
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Quantifying hurricane wind speed with undersea sound
… Here we model microseisms generated by the spatially inhomogeneous waves of a hurricane with the non-linear wave equation where a second-order acoustic field is created by first-order ocean surface wave motion. We account for the propagation of microseismic noise through range-dependent …
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Pattern Formation in Active Nematics
… driven negative by activity. We show that spatially inhomogeneous patterns are selected via a mechanism analogous to that responsible for modulated phases at an equilibrium Lifshitz point.</p>
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Evolution of the excitation spectrum of cuprate superconductors with doping and temperature
… of our data shows no correlation between the inhomogeneous pairing gaps and either the energy scale of the boson modes or the strength of the local electron-boson coupling as measured by the local excitation spectra. This spatially inhomogeneous pairing strength is in fact determined by the …
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Modelling large scale ocean circulation : the role of mixing location and meridional pressure gradients for the Atlantic overturning dynamics
… circulation model and discusses the role of spatially inhomogeneous mixing, numerical diffusion and winds. Furthermore, the relation of the AMOC with a key quantity, the meridional pressure difference is analyzed. Due to the application of a very low diffusive tracer advection scheme, a …
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Proximity effects and vortex dynamics in mesoscopic superconductor-normal metal-superconductor arrays
… pertain to conventional metals, but rather to spatially inhomogeneous correlated states. Determining the origin and characteristics of such states has attracted intense theoretical and experimental interest over the past two decades. Contributing to these efforts, we engineer a tunable, …
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Self-Consistent Study of Topological Superconductivity in Two-Dimensional Quasicrystals
… self-consistently obtained mean fields are both spatially inhomogeneous. In particular, we examine how the underlying aperiodic structure of a QC is reflected in the superconducting order parameter.
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Ultrafast lattice dynamics in photoexcited nanostructures : femtosecond X-ray diffraction with optimized evaluation schemes
… optically excited electrons in this material a spatially and temporally well-defined thermal stress profile is generated in SrRuO3. This enables understanding the effect of the resulting coherent lattice dynamics in time-resolved X-ray diffraction data in great detail, e.g. the appearance of a …
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