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 67 for “"Physical Basis"”.
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The Physical Basis of Extreme Animal Coloration
… little work has been done to examine the physical basis of extreme coloration across taxa. In this dissertation, I use butterflies, deep-sea fishes, and cleaner shrimp to further explore the presence of extreme coloration in different taxa and the underlying color production mechanisms. In …
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Establishing the Physical Basis for Calcification by Amorphous Pathways
… Furthermore, results suggest a chemical basis for a broad range of Mg contents in calcite, including high Mg calcite. We find that the final calcite produced from ACC is similar to the composition of the initial ACC phase, suggesting that calcite composition reflects local conditions of …
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A Purkinje cell Timing Mechanism. On the Physical Basis of a Temporal Duration Memory.
… a metabotropic signaling cascade constitutes a physical memory of temporal duration. A theoretical model (paper IV) describes how this could be accomplished by a learning mechanism that selects among a finite number of regulatory proteins, those which bestow the intracellular signaling cascade …
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Uncertainty In The Physical Basis of Estimates of Relative Biological Effectiveness In Carbon Radiotherapy
… prescribed. Additionally, uncertainty in RBE by physical parameters and model assumptions have not been well characterized, which makes it difficult to understand where model differences arise.</p> <p>The aim of this work is to create a robust measurement-based program with which to validate …
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Geophysical parameter estimation with a passive microwave spectrometer at 54 / 118 / 183 / 425 GHz
… a convective cell is presented that provides a physical basis for this relationship.
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The evolution of vortices in a turbulent boundary layer
… turbulent velocity fields and hypotheses for the physical basis of turbulence; however, the fundamental physics of turbulence remain unknown. In this investigation, the evolution of a perturbed vortex tube near a boundary is examined in order to gain insight into turbulent boundary layer …
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Magnetic Resonance Imaging by Populations in the Presence of Molecular Diffusion
… simulations (chapters 3 and 4) to delineate the physical basis of MRI by populations and predict enhancements of performance. Chapters 3 and 4 predict the resolution of the method for ideal spatial geometries. Chapter 5 predicts the attainable sensitivity. In chapter 6, dimensional analysis …
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Biophysical studies of chromatin folding and unfolding
… and unfolded by several levels, providing a physical basis of coordinated DNA functions in eukaryotic cells. Chromatin folding is started with a linear long string of nucleosomes, connected by segments of DNA called linker DNA. Further folding forms the higher order structure, 30-nm fibers in …
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A novel framework for acoustic diagnostic of artificial lift system for oil-production
… the pump operation can thus be monitored. The physical basis of this acoustic method is demonstrated using results from a model of the rod-pump system complemented by field data measured from representative operating oil wells. The rod pump model has shown to be in good accord with available …
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Evaluation of Knox group contribution parameters using quantum based molecular and group properties
… in the past present not only limitations on the physical basis but often have restrictions as to certain substances, such as isomers. A new group contribution method is proposed that uses AIM theory, which is based on computational chemistry and quantum mechanics, to overcome these limitations by …
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Inlet drag prediction for aircraft conceptual design
… the analysis, the drag calculations have a sound physical basis. The semi-empirical methods have been extracted from a number of sources based on an extensive literature survey, and these have been enhanced to encompass the full range of inlet operating conditions. The effectiveness of the methods …
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Theory and simulation of subwavelength high contrast gratings and their applications in vertical-cavity surface-emitting laser devices
… gratings are diffraction gratings with physical dimensions less than the wavelength of incident light. It has been found that by tailoring specific dimension parameters, a number of different reflection profiles can be attained by these structures including high reflectivity or low …
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Using simulation to estimate probability density functions of bound water molecules with DSI
In order to explore the physical basis by which high resolution diffusion imaging derives information about fiber alignment and diameter, we simulated a model diffusion experiment employing a random walk paradigm. A simulation of a model diffusion spectrum imaging experiment was written in Java in …
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The effect of spark timing on residual gas fraction
… Since the data was taken over a limited range, a physical basis for a correlation was developed. Following the approach used in a previous modeling effort, the residual gas fraction was modeled as the sum of two contributing factors: backflow from the exhaust port to the cylinder during valve …
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Issues related to finite element techniques for two dimensional transmission structures
… multipliers, with attention given to the physical basis of the obtained functional. This model is then applied to the problem of determining the propagation constant of a waveguide.
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Modeling dislocation density evolution in continuum crystal plasticity
… has long been understood as the underlying physical basis for continuum crystal plasticity formulations, explicit consideration of crystallo- graphic dislocation mechanics has been largely absent in working constitutive models. In light of recent theoretical developments in dislocation …
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Predicting the Air-Side Thermal -Hydraulic Performance Characteristics of Flat-Tube Louver-Fin Heat Exchangers Under Dry and Wet Conditions
… expanding the parameter space and establishing a physical basis for the form of the fits. However, it is found that multivariate non-parametric regressions can dramatically reduce the RMS errors if a large, well-structured dataset is used. Furthermore, this method provides statistical indicators …
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Fluctuation conductivity from charge density waves in pseudo-one-dimensional systems
… of the Fröhlich mechanism are reviewed. The physical basis of the Fröhlich model is discussed in detail and is extended by the new suggestion that the important Fröhlich mode frequencies are less than the Kohn anomaly frequency. A phenomenological formulation of the free energy is used to …
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Model for an exciton mechanism of superconductivity in planar geometry
… experimentally, the theory has a sound physical basis and indicates that the effect of the exciton mechanism ought to be observable in"" favorable samples with sufficient effort. The immediate need is to fabricate such systems and establish the existence of the exciton mechanism of …
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