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Item Algal biofilms, microbial fuel cells, and implementation of state-of-the-art research into chemical and biological engineering laboratories(Montana State University - Bozeman, College of Engineering, 2010) Menicucci, Joseph Anthony Jr.; Chairperson, Graduate Committee: Ron LarsenAlternative energy technologies become more attractive as the price of energy from fossil fuels becomes more expensive and the environmental concerns from their use mount. While a number of biological alternative energy technologies currently exist, a complete understanding of these technologies has yet to be developed. This dissertation characterizes an aspect of biological alternative energy technologies: the production of algal biofuels and energy conversion in microbial fuel cells. Specifically, this dissertation addresses the characterization of microalgae as a biofilm and the characterization of the power limitations of microbial fuel cells. The attachment and detachment of algae were observed using temporal microscopic imaging in a flow-cell with autofluorescence and staining techniques as part of a collaborative Montana State University and Idaho National Laboratory project. Colonies of algae exhibit many characteristics seen in bacterial biofilms: adherence; detachment and sloughing; difference in structure of an attached colony; varying strength of attachment on different surfaces; association of other organisms in an EPS matrix; and the heterogeneous nature of attached colonies. The characterization of a microbial fuel cell was completed in less than 30 minutes using an empirical procedure to predict the maximum sustainable power that can be generated by a microbial fuel cell over a short period of time. In this procedure, the external resistance was changed incrementally, in steps of 500 ohms every 60 seconds, and the anode potential, the cathode potential, and the cell current were measured. This procedure highlights the inherent limitations of energy conversion in a microbial fuel cell. A voltage/current characterization of the microbial fuel was also completed from the data collected. This dissertation also includes the evaluation of A Hands-On Introduction to Microbial Fuel Cells, a laboratory developed for an introductory chemical and biological engineering course. The experiment has been updated to include a voltage/current characterization of the microbial fuel cell. Learning objectives have been identified and pre- and post-laboratory activities have been developed for further implementation into a chemical and biological engineering curriculum.Item Nuclear magnetic resonance microscopy of NAFION-117 proton exchange polymer membranes(Montana State University - Bozeman, College of Engineering, 2004) Howe, Daniel Trusler; Chairperson, Graduate Committee: Joseph SeymourAs the combustion of fossil fuels for the generation of energy and transportation becomes more expensive, of limited supply, and environmentally unsound, the development of viable fuel cell alternatives becomes more important. A comprehensive understanding of the proton exchange membranes (PEM's) used as electrolytes in certain types of fuel cells will play a major role in bringing the cost and reliability of PEM fuel cell systems down to a competitive level with traditional fossil fuel methods. Magnetic resonance microscopy (MRM) is well suited to the study of these membranes because it is non-invasive, and can spatially resolve material structure and give data on transport phenomena such as diffusion that cannot be determined by other methods. The goal of this research was to use magnetic resonance microscopy to study solvent mobility levels within the polymer membranes via spin-spin, T2, magnetic relaxation and diffusion mapping. The molecular mobility can quantify membrane swelling and spatial heterogeneity of the membrane material. A key aim of the research is to correlate these findings with previous bulk MRM studies of solvent within polymer membranes. Prior bulk MRM studies of solvent molecular mobility at different hydration levels were unable to study the membranes fully submersed in solvents, as the free solvent signal would dominate the nuclear magnetic resonance (NMR) signal from the solvent within the membrane. In this study spatial resolution of the MRM data provides the means to study fully saturated membranes, a condition of interest since the degree of hydration is related to membrane operational efficiency. The material homogeneity of the polymer in the thickness and surface directions of the membrane, an important factor in the reliable performance of fuel cells, was studied via T2 mapping. Nafion®-117 was the proton exchange membrane studied because it is currently the most popular electrolyte used in the PEM fuel cell industry and several bulk MRM studies have been conducted. Results indicate that both solvent mobility and membrane swelling are highly dependant on the concentration of methanol used to prepare the samples, as seen in the bulk studies, and that solvent mobility can vary on the 20 micron level within the polymer in both the thickness and surface directions. This research establishes MRM as an important tool for the study of individual proton exchange polymer membrane samples and provides a basis for extension to the study of membranes during operation.