The ZEBRA battery based on Na/NiCb chemistry shows promise for powering electric vehicles and load leveling systems. The ZEBRA cell consists of a liquid sodium negative electrode separated from the positive electrode by a W'-alumina solid electrolyte. The current state of development of this battery makes use of glass sealing and thermo compression sealing as an integral part of the cell assembly. One objective of the present research was to reduce the thickness of the W'alumina electrolyte thickness as a means to improve perfomance, by lowering the internal cell resistance. The second objective was to develop a ceramic seal with matching thermal expansion coefficient (TEC) to increase battery durability. An added benefit realized with the new ceramic seal was its use for high temperature applications such as emf measurements ordinary systems to determine thermodynamic properties. Dense electrolyte tubes with reduced thickness of less than 100 J..Lm and supported on a porous substrate were successfully produced by slip casting. The slip casting parameters, sintering conditions and materials were optimized and electrolyte resistance was measured by a DC method. A ceramic seal was developed from a eutectic mixture of Na20 and Al203 and tested in galvanic cells. The reproducibility of the emf data shows that the seal is fully impervious and can sustain a high alkali pressure atmosphere up to 1 000°C without cracking or degradation. The seal microstructure revealed liquid phase formation of the seal and diffusion bonding with the lid and tube. The thermodynamic properties and phase relations of the Na-Si binary system were studied by the emf method using Na|β-alumina|Si-Na galvanic cells over the whole composition range below 600°C. There is very limited solubility of Si in molten Na. Properties of the sodium silicon compounds were determined from the emf measurements. / Thesis / Doctor of Philosophy (PhD)

Inkjet printing of ceramic components and gold conductive tracks was carried out in this study. A commercial inkjet printer, designed for printing one layer of 2D images on paper, was modified to give adequate resolution, to reverse the substrate for overprinting many layers and to accommodate the increase in thickness of 3D components during printing. Ceramic inks were prepared by wet ball milling and printed to form 3D structures. The powders used were alumina, zirconia, lead zirconate titanate (PZT) and barium titanate. The substrate used for printing the ceramic parts was an overhead transparency. Methods to stop or reduce ink flow were devised and used during printing of the ceramic parts. The alumina and zirconia powders were used for the fabrication of multi-layered laminates. The lead zirconate titanate was used to fabricate components with pillars, walls, vertical channels and x-y-z channel network. During printing of the x-y-z channel network, carbon was used as a support structure and then removed during firing. Barium titanate and carbon powders were used to form the first storey of a capacitor with a multi-storey car park structure. The printed parts were pyrolysed and fired in an oxidising environment and then characterised with scanning electron microscopy. The causes of micro structural defects found were discussed and prevention methods suggested. Organic gold powder was dissolved in methanol and then printed on three different substrates to form conductive gold tracks. The substrates used included alumina, glazed tile and microscope glass slides. The printed tracks were fired in air. The decomposition characteristics of the organic gold compound were studied with TGA and Differential Scanning Calorimetry (DSC). Scanning electron microscope was used to examine the fired gold film for defects and conductivity measurement of the tracks was carried out with a programmable multimeter.

"Current approaches to design are often serial and iterative in nature, leading to poor quality of design and reduced productivity. Complex artifacts are designed by groups of experts, each with his/her own area of expertise. Hence design can be modeled as a cooperative multi-agent problem-solving task, where different agents possess different expertise and evaluation criteria. New techniques for Concurrent Design, which emphasize parallel interaction among design experts involved, are needed. During this concurrent design process, disagreements may arise among the expert agents as the design is being produced. The process by which these differences are resolve to arrive at a common set of design decisions is called Negotiation. The main issues associated with the negotiation process are, whether negotiation should be centralized or distributed, the language of communication and the negotiation strategy. The goals of this thesis are to study the work done by various researchers in this field, to do a comarative analysis of their work and to design and implement an approach to handle negotiation between expert agents in an existing Concurrent Engineering Design System."