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 10 of 10 for “"Fractal model"”.
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Electron spin-lattice relaxation in proteins, model heme complexes and ferricyanide solutions at helium temperatures
… has been tentatively explained in terms of a fractal model of protein dynamics, where the temperature exponent is n = 4q + 2d - 1 and q = dd$\sb{\varphi}$/D. The localized vibrations (fractons) are characterized by a localization exponent d$\sb{\varphi}$ on an underlying fractal lattice with …
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Spin lattice relaxation studies on iron proteins
The fractal model relating protein structure and vibrational dynamics is reviewed and refined. The temperature dependence of electron spin-lattice relaxation stimulated by Raman phonon scattering is measured in low spin ferric proteins. The data are analysed to yield the spectral dimension, a …
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Analysis of gas differential diffusion through porous media using prompt gamma activation analysis
… noble gases in a porous medium. I also present a model to estimate the connectivity parameter of a soil from measurements of its saturated conductivity, macro porosity, and pore volume and pore surface fractal dimensions. Experiments with argon or xenon diffusing through a nitrogen saturated …
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SUB-SURFACE MIGRATION OF AN OIL POLLUTANT INTO AQUIFERS
… Experimental data is used to establish modelling capabilities for the characterisation of pollutant migration. Modelling is undertaken at two levels. The first consists of the development of simple Gaussian equations based upon observations of oil glomuses. The glomus approach, newly …
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Investigations on Multiscale Fractal-textured Superhydrophobic and Solar Selective Coatings
… of multiscale coatings by presenting a fractal model to describe wettability on such surfaces. These surfaces are described with a fractal asperity model based on the Weierstrass-Mandelbrot function. Using this description, a model is presented to evaluate the apparent contact angle in …
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Transients in Polymer Electrolyte Membrane (PEM) Fuel Cells
… in the porous structures with time. A dynamic fractal model is introduced to describe such structures undergoing deposition and, in turn, to evaluate the changes in their physical properties as a function of the deposition.
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SOME MAGNETIC PROPERTIES OF BORE CORE SEDIMENTS
… Such DIRM correlated well with the theoretically modelled magnetic field at one end of a steel drill barrel. The DIRM intensity distribution also appeared to be correlated with variation in the radial remanence susceptibility (i.e. the capacity of remanence acquisition) in the North Sea and …
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Solute transport in layered and heterogeneous soils
… of soils and aquifers. We proposed a fractal model to explain the time dependency of dispersivity. Our model indicates a nonlinear increase of variance of travel distance with time or mean travel distance, which implies a time-dependent dispersivity. Application of our model to three …
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A Radiative Analysis of Angular Signatures and Oblique Radiance Retrievals Over the Polar Regions From the Multi-Angle Imaging Spectroradiometer
… TRANsmission (MODTRAN) radiative transfer model, this dissertation provides the first explanation of the conditions that lead to the brighter or darker appearance of clouds relative to the surface at nadir by introducing the transition albedo. The transition albedo shows that clouds darken …
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Characterization of tight and shale unconventional gas reservoirs using low field NMR
… significant value in reserve estimation and flow modelling. These characteristics are challenging parameters to measure. On the other hand, oil and gas sectors are continually looking for ways to do more with less environmental impact and greater operational efficiency. Nuclear Magnetic Resonance …