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 53 for “"diffusion rates"”.
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Diffusion Rates in Face-Centered Cubic Copper - Zinc Alloys During Torsional Deformation
Made available in DSpace on 2014-12-04T23:26:51Z (GMT). No. of bitstreams: 1 6202929.pdf: 1462690 bytes, checksum: 0ed32bec9cefa7cd65b1ead5d2f10a50 (MD5) Previous issue date: 1962
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High resolution NMR scattering : the first measurement of spin diffusion rates in a homogeneous solid
The first direct measurement of the rate of spin diffusion through a homogeneous sample was performed as an incoherent NMR scattering experiment. The experiment consists of a combination of pulsed gradient spin echo methods with multiple pulse/ pulsed gradient spatial encoding met.hods. The NMR …
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Ab initio screening of lithium diffusion rates in transition metal oxide cathodes for lithium ion batteries
A screening metric for diffusion limitations in lithium ion battery cathodes is derived using transition state theory and common materials properties. The metric relies on net activation barrier for lithium diffusion. Several cathode materials are screened using this approach: [beta]'-LiFePO4, …
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A new approach to the study of surface phenomena, measurements of diffusion rates, intermolecular distances and electronic properties of CO chemisorbed on supported platinum catalysts by nuclear magnetic resonance
… from 300 K to 600 K from which he deduces diffusion energies of 13 and 16 plus/minus 2 kcal/mol, in agreement with measurements of R. Lewis and R. Gomer of the diffusion of CO on Pt tips by Field Emission Microscopy. He demonstrates that conduction electrons are present on CO and shows that …
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A New Approach to the Study of Surface Phenomena: Measurements of Diffusion Rates, Intermolecular Distances and Electronic Properties of Carbon Monoxide Chemisorbed on Supported Platinum Catalysts by Nuclear Magnetic Resonance
The author has applied magnetic resonance to study the chemisorption of CO on supported platinum particles. The particles are 10 to 50 (ANGSTROM) in diameter, supported on alumina. CO is 90% enriched with ('13)CO. NMR data were taken from 4 K to 600 K.
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Activated Carbon Injection for Mercury Control in Coal-Fired Boilers
… We are interested in determining whether the diffusion rate or the absorptive capacity of the sorbent particle limits mercury absorption. A mathematical model was developed to estimate mercury diffusion rates in flue gas. With the model, diffusion rates were studied for mono-sized particles, …
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An investigation of atmospheric turbulence in the 100-105 km region over Cerro Pachón, Chile
… Na mixing ratio, and total constituent diffusion coefficient measurements. Twenty-seven (27) nights of lidar data spanning 2500 hours in the zenith and 2375 hours in the off-zenith directions at 25 m, 6 s resolution were analyzed to determine mean turbulence and instability trends in the …
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Interactions between selected metal compounds and marine heterotrophic bacteria
… bacteria. The technique was based on the agar diffusion method. Reliability and reproducibility were enhanced by careful standardisation of experimental parameters. By quantification of the concentration of metal compounds in the media using sequential strips of agar it was .possible to prepare …
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Effects of Fertility Control on the Movement Ecology of White-Tailed Deer
… the relationship between mean speeds and diffusion rates using continuous-time speed and distance estimation techniques. Accurate modeling of an animal’s speed and distance traveled can be critical for interpreting behavior, yet ecological data often are too coarse, or the location error …
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Channeling studies of the location of zinc in gallium-arsenide
The diffusion of zinc in GaAs is highly anomalous in that the diffusion coefficient (D) is proportional to the zinc concentration squared in marked contrast to Fick's law which predicts that D is concentration independent. D is also very sensitive to the ambient conditions during diffusion, …
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Microstructural effects on capacity-rate performance of vanadium oxide cathodes in lithium-ion batteries
… by sputtering onto ITO-coated glass substrates and crystallized in a refined annealing process to generate diverse microstructures. Average grain size and grain size distribution were determined in SEM analysis. No significant difference was observed in capacity rate behavior with changes …
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Development of Kirkwood-Buff derived force field for phospholipids
… the area and volume per lipid, the lipid lateral diffusion rates, and the hydrocarbon chain order parameters, were investigated and compared with experimental data where available.
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Kinetics of chemical exchange during melting of planetary interiors
… planets. Chapter 1 presents experiments on the diffusion rates of La, Ce, Nd, Dy and Yb in diopside at pressures of 0 to 2.5 GPa and temperatures of 1050 to 1450 'C. The results demonstrate a large variation in diffusivity among the rare earth elements, with the diffusion coefficient for La a …
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Mass transport in metal-organic frameworks as a limiting step in size-selective oligomerization
… propylene-glycol methyl ethers as model substrates, the mass transport properties of these materials was investigated. Unfortunately, slow mass transport of solvated substrates through pores assumed to be sufficiently large for facile diffusion may prevent MOFs from serving as suitable …
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Transition Metal Oxides for Cathode of Li-ion Battery
… stability, electrochemical impedance and diffusion rates. Differences in cation mixing degree were observed with variations in the dopant addition level and this was reflective of differences in substitution mechanisms. The particles were sub-angular in morphology with uniform …
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"Thermal-burst modeling of a double-diffusive ""diffusive"" interface"
… break away due to the differing component diffusion rates. The quasi-steady entraining model assumes a thin interface where each burst entrains fluid up to the limit of neutral buoyancy. This entrainment assumption fixes the flux ratio at one and predicts normalized flux rates which are in …
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Characterization of Local field effect in organic film using pressure technique
This thesis proposes and demonstrates a pressure probing technique for studying the effects of local dielectric changes on the excitonic energy levels in amorphous organic thin films for optoelectronic device applications. Compression of organic films causes a decrease in intermolecular spacing …
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Evaluating Competitive Sorption Mechanisms of Volatile Organic Chemical Mixtures in Soils and Sediments Using Polymers and Zeolites
… control competitive sorption and mass transfer rates of sorbate mixtures. To test this hypothesis, aqueous isotherms and desorption kinetic profiles for trichloroethylene (TCE) and tetrachloroethylene (PCE), either alone or in a mixture, were measured at 30°C for three natural solids, two …
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Measuring and Comparing the Diffusion Rate of Fluorescent-Lipophilic-Neurotracing Probes in Murine-Peripheral-Nerve Preparations
… trace such circuitry, it is necessary to use a diffusion-matched set of spectrally distinct dyes. The fluorescent dye molecule is composed of a fluorescent head group and two hydrocarbon chains. This thesis addresses how the molecular structure of a lipophilic-fluorescent dye affects the …
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Protein Dynamics: Studies of Adenylate Kinase Mutants From Escherichia Coli and Characterization of Adenylate Kinase Isoforms From Murine Cells. Applications of Fluorescence Spectroscopy and Microscopy
… was mainly localized on the plasma membrane. The diffusion rates of AK1-EGFP and AK1beta-EGFP obtained from FCS measurements suggested that AK1 diffused freely in the cytosol of the cell, while AK1beta was bound to the plasma membrane. It has been suggested that AK1beta interacts with the plasma …
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