Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xvi, 140 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 123-131).

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: John B. Goodenough. Vita. Includes bibliographical references. Also available from UMI.

Dissertation (Ph.D.)--Worcester Polytechnic Institute. / Keywords: Fuel Cells, Polymer, Composite, High Temperature, Nafion. Includes bibliographical references. (leaves p.).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1977. / Vita. Abstract. Includes bibliographical references (leaves 122-124). Also available via the Internet.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1978. / Vita. Abstract. Includes bibliographical references (leaves 193-197). Also available via the Internet.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 136-143). Also available on the World Wide Web.

Made available in DSpace on 2014-10-09T12:37:03Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:36Z (GMT). No. of bitstreams: 1 04490.pdf: 6751452 bytes, checksum: b98c1dc1b829918d01b97249140225c3 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The research work presented in this thesis is concerned with an investigation of fuel management of diesel engines for the purposes of developing control schemes to improve fuel consumption, exhaust emissions and engine controllability.

Hydrogen fuel cells have held out the promise of clean, sustainable power generation for decades, but have failed to deliver on that potential. Inefficiencies in research and development work can be overcome to increase the rate of new knowledge acquisition in this field. A number of medical and engineering disciplines utilise a wide variety of statistical tools in their research to achieve this same end, but there has been little adoption of such statistical approaches within the fuel cell research community. This research undertakes a design of experiments (DoE) approach to the analysis of multiply-covarying (M-ANOVAR) factors by using historic data, and direct experimental work, on a wide variety of polymer electrolyte membrane fuel cells (PEMFCs) cathode gas diffusion media (GDM) and dual layered catalyst structures. This research developed a gradient of polarisation regions' approach; a method for making robust numerical comparisons between large numbers of samples based on polarisation curves, while still measuring the more usual peak power of the PEMFC. The assessment of polarisation gradients was completed in a statistically robust fashion that enabled the creation of regression models of GDMs for multiple input and multiple output data sets. Having established the multivariate method; a set of possibly co-varying factors, a DoE approach was used to assess GDM selection, dual layered catalyst structures and degradation of membrane electrode assembly (MEA) performance over time. Degradation studies monopolise resources to be monopolised for protracted periods. M-ANOVAR allows the addition of other factors in the study, and the total efficiency of the degradation experiment is increased. A 20% reduction in the number of samples to be tested was achieved in the case study presented in this thesis (compared to the usual one factor at a time (OFAT) approach). This research highlights the flexibility and efficiency of DoE approaches to PEMFC degradation experimentation. This research is unique in that it creates catalyst ink formulations where the variation in catalyst loading in each sub-layer of the catalyst layer (CL) was achieved by having a different concentration of the catalyst material on the carbon supports. The final M-ANOVAR analysis indicates a simple average of the individual responses was appropriate for the experiments undertaken. It was shown that low concentration dual layer catalysts on paper GDMs have improved performance compared to paper GDMs with uniform, single layer catalysts: Demonstrating reduced platinum concentrations to achieve equivalent open cell performance. The time to peak power during testing (how long after starting the test it takes to achieve the maximum performance in the cell) was strongly impacted by GDM selection. Furthermore, there was a strong suggestion that previously published results crediting a change in performance due to a single layer, or multi-layered catalyst structures may, in fact, have been due to the selection of GDM used in the experiment instead.

Work on modelling compounds possessing die tetraaza[14]annulene (TAA) fragment is described. Modelling studies have been conducted to investigate both structural and electronic properties, of both single molecules and extended arrays of these compounds. The structural aspects have been investigated using molecular mechanics and crystallographic database investigations. Molecules based on the tetraaza[14] annulene structure have been found to adopt one of four conformations. The geometries of these conformations are planar, saddle-shaped, slightly twisted, and dome-shaped. The complexed metal centre and the arrangement of substituents on the periphery of the ligand, have been found to determine which conformation a molecule adopts. In order to model the compounds, three new atom types have been created for the Universal Force Field. The electronic aspects have been investigated using Hartree Fock based calculations for single molecules and Extended Huckel based calculations for extended systems. The electronics of die single molecules have shown there to be a linear trend in the LUMO energies, although die HOMO energies vary very little. The reason for this trend in the LUMOs is unknown, but appears not to be related to any obvious structural feature.