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 39 for “"diffusion constant"”.
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The development of a field procedure for determining the chloride content of concrete and an analysis in the variability of the effective diffusion constant
… An analysis of the variability in the effective diffusion constant for the bridges tested was also performed to determine any relationships which exist between different exposure groups and to determine effects of time.
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Determination of chloride diffusion constants for concretes of differing water to cement ratios and admixtures
… function of time, a driving concentration, and a diffusion constant. The diffusion constant varies with temperature and the variety of concrete . The research included determination of diffusion constants for six types of concretes after 8 weeks and 16 weeks of ponding with an NaC1 solution. In …
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Statistical Physics of Semidilute Polymer Systems (And); Soft Billiard Systems
… model for the calculation of the cooperative diffusion constant and the initial decay rate of the dynamic scattering function. Our results for these quantities show good agreement with experiment for moderately dense systems. Finally, we discuss the mode-coupling method, in order to study …
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Ultrafast studies of diffusion and electron transfer
… way using a simple, analytically tractable diffusion model involving just three parameters: the relative diffusion constant, the contact radius, and the intrinsic rate of reaction at contact.
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Relaxation phenomena during non-equilibrium growth
… or to a quantity which is conjugated to the diffusion constant. The global quantities depend in a non-trivial way on two different times. We discuss the dynamical scaling forms of global correlation and response functions. For global functions related to the surface width, we show that the …
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A molecular theory of the Stokes-Einstein relationship
… between the translational and rotational diffusion constants of a molecule in a liquid and the liquid's shear viscosity. Such a relationship was derived by Einstein using the equations of hydrodynamics, treating the liquid as a continuous incompressible medium, the diffusing molecule as a …
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Classical Hamiltonian dynamics of a particle interacting with the vibrational modes of a one-dimensional medium
… fundamental transport quantities as the polaron diffusion constant. This thesis introduces a classical model which incorporates the essential features of a particle coupling to the surrounding vibrational modes. With this simple model it is possible to numerically evaluate the equations of motion …
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Something to do with Schrödinger spacetimes
… including the shear viscosity and the shear diffusion constant giving results consistent with other hydrodynamic analyses of the system.
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Statistical physics of semidilute polymer systems soft billiard systems
… model for the calculation of the cooperative diffusion constant and the initial decay rate of the dynamic scattering function. Our results for these quantities show good agreement with experiment for moderately dense systems. Finally, we discuss the mode-coupling method, in order to study …
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Nanoparticle Transport Through Fractures And Heterogeneous Porous Media
Nanoparticles have a diffusion constant a couple of orders of magnitude smaller than inert chemical tracers such as potassium bromide (KBr), and this means that they can potentially be used to measure the degree to which subsurface flow occurs through fractures and high permeable zones in …
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Theory of the general orientation dependence of ²H NMR spin-lattice relaxation and experiments on model membranes
… to be negative. The rotational diffusion model as formulated by Schindler and Seelig (Biochem.14:2283) is incorrect based on the range of experimentally acceptable S40. The fluctuations of the CD bond were successfully modelled as a uniform distribution. There is a spectrum of …
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Modeling of Kinetically Limited Growth Rate for Solution-Synthesized Germanium Nanocrystals
… studies have assumed that the growth rate is diffusion-limited with an unphysically low diffusion constant. In this thesis, a model is developed that considers both diffusion and surface kinetics. The diffusion coefficient of Ge monomers through the solvent, octadecene, at elevated synthesis …
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Coherent Transport of Matter Waves in Disordered Optical Potentials
… effects, which entail a renormalization of the diffusion constant as compared to the classical description. This so-called weak localization of matter waves is studied as the underlying mechanism for the disorder-driven transition to the Anderson-localization regime, explicitly taking into …
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The Si/SiO2 Interface Roughness
… roughness are related to oxidation rate and diffusion constant in this model. The effect of chemical processing on the starting surface of silicon was also studied. Other related issues such as imaging processing, the
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Feedback control of complex oscillatory systems
… of phase dynamics is evaluated by the phase diffusion constant, which is in its turn proportional to the width of the spectral peak of oscillations. Many chaotic oscillators can be described within the framework of phase dynamics, and, therefore, their coherence can be also quantified by the …
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The Si/SiO(2) Interface Roughness
… roughness are related to oxidation rate and diffusion constant in this model. The effect of chemical processing on the starting surface of silicon was also studied. Other related issues such as imaging processing, the experimental set-up and the future directions in this field are also …
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EXPERIMENTAL CHARACTERIZATION AND MODELING OF ASPECT-RATIO-DEPENDENT DIFFUSION OF NANOCRYSTALS IN NANOCHANNELS
The investigation of aspect-ratio-dependent diffusion and equilibrium partitioning of semiconductor nanocrystals in rectangular nanochannels has been undertaken. The nanocrystals are terminated with hydrocarbon ligands and suspended in toluene, considered an aprotic solvent. Time-dependent …
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DIRECT REAL-TIME REAL-SPACE IMAGING OF ENERGY TRANSPORT IN ORGANIC SEMI-CONDUCTORS
… pentacene and may diffuse efficiently with a diffusion constant D in excess of 200 cms⁻¹, much larger than reported values for excitons in organic and inorganic semiconductors. The ability to visualise ultrafast charge separation at a junction with nanometre resolution will help to develop a …
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Investigation of Waterborne Epoxies for E-Glass Composites
… laminated composites. No increases in the diffusion constant could be attributed to the surfactant. However, the surfactant did enhance the final equilibrium moisture uptake levels. These equilibrium moisture uptake levels were also sensitive to the surface pretreatment of the E-glass.
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