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 13 of 13 for “"mass transport limitations"”.
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Mechanistic understanding of microbial desulfurization
… major obstacles to commercialization of BDS are mass transport limitations and the inability to maintain biocatalyst activity for long periods of time. In this work, the mass transport limitations were studied in a small-scale model system consisting of a resting cell suspension of Rhodococcus …
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Water Management in the PEM Fuel Cell by Incorporating a Novel Siloxane Polymer in the Electrode Layer
… dominated by kinetic, ohmic resistance and mass transport limitations, the results show a positive influence of COMP-1 at 50% to 60% RH conditions, but it is not clear that water retention is the cause.
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A model for analyzing the effects of hydrodynamic forces on cell adhesion in a perfused bioreactor
… that aim to provide a convective flux to address mass transport limitations of oxygen and other nutrients, large hydrodynamic forces and shear stress can potentially serve as a negative signals in tissue formation and morphogenesis. Shear stress and hydrodynamic forces may inhibit the formation of …
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The Impacts of Particle Size Distribution and Electrode Structuring on NMC Cathode Performance
Electrifying the transportation sector is not just a necessity but an urgent call to action in curbing carbon emissions. To facilitate the widespread adoption of electric vehicles, lithium-ion batteries with extended lifespans, increased energy densities, and rapid charging capabilities are needed. …
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Development of biodegradable microfluidic networks for tissue engineering
… geometries, lack of reproducibility, and severe mass transport limitations. Microfabrication is an ideal tool for attacking problems in tissue engineering due to its control of diverse size scales, from microns to centimeters, all with micron resolution and submicron precision. By enabling …
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Photocatalysis in a novel semiconducting optical fiber monolithic reactor for wastewater treatment
… coating per unit reactor volume, reduces the mass transport limitations, and allows for high throughput at low pressure drop. Using optical fiber to deliver UV light can remotely control the reactor. The effects of water flow velocity, initial contaminant concentration, thickness of the TiO2 …
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Durability study of proton exchange membrane fuel cells via experimental investigations and mathematical modeling
… of pinholes at approximately 500-600h, and mass transport limitations are the major degradation sources for constant current mode. A phenomenological mathematical model is set up to describe the PEMFC aging process under both cyclic and constant conditions.
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Ultrasonically Enhanced Mass Transport and Degradation of Polycyclic Aromatic Hydrocarbons in Solid-Liquid Two Phase Partitioning Systems
… such a process was successful, significant mass transport limitations involving PAH release from the polymers hampered productivity. The current work examined the possibility of applying sonication in solid-liquid partitioning systems to enhance delivery and degradation of PAHs. Small scale …
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Directly enhancing the photocatalytic transformation of CO2 and water to renewable fuels.
… of the system through the elimination of mass transport limitations and increasing light penetration. The optimum conditions for H2 evolution were found to be a propeller rotational speed of 1035 rpm and 144 W of simulated solar irradiation, which produced a rate of 109 μmol h-1 g-1 over …
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Cardiac tissue engineering : bioreactor cultivation parameters
… of mostly empty space due to diffusional mass transport limitations. We attempted to overcome diffusional limitations by directly perfusing culture medium through the constructs. Perfusion significantly improved the uniformity of the cell distribution and enhanced expression of a …
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Evaluation of process parameters and membranes for SO2 electrolysis
… charge transfer resistance, ohmic resistance and mass transport limitations. Results showed that the optimal hot pressing conditions were 125 kg.cm-2 and 50 kg.cm-2 for 5 minutes when using 25 and 10 cm2 active areas, respectively. The charge transfer resistance and mass transport were mostly …
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Understanding and Improving Electrochemical CO2 Capture by Supercapacitive Swing Adsorption
… faster than 30 mA g−1 a decrease was seen due to mass transport limitations of both CO2 and bicarbonate ions. The potential mechanism uncovered suggested the current flowing through the gas exposed electrode controls the behaviour of the device. Therefore, to investigate this further, the gas cell …
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Characterization of catalyst pellets using NMR and MRI: MRI, diffusion and relaxation measurements of liquid imbibed in alumina and titania extrudates
… (MRI) techniques with the aim of characterizing mass transport in the pellets and exploring the presence of spatial heterogeneities formed in the manufacturing process. Measurements have been done both in bulk, i.e. spatially unresolved, and at high spatial resolution. Measurements have been used …