An Insulating Glass Knowledge Base

This report will discuss issues relevant to Insulating Glass (IG) durability performance by presenting the observations and developed conclusions in a logical sequential format. This concluding effort discusses Phase II activities and focuses on beginning to quantifying IG durability issues while continuing the approach presented in the Phase I activities (Appendix 1) which discuss a qualitative assessment of durability issues. Phase II developed a focus around two specific IG design classes previously presented in Phase I of this project. The typical box spacer and thermoplastic spacer design including their Failure Modes and Effect Analysis (FMEA) and Fault Tree diagrams were chosen to address two currently used IG design options with varying components and failure modes. The system failures occur due to failures of components or their interfaces. Efforts to begin quantifying the durability issues focused on the development and delivery of an included computer based IG durability simulation program. The focus/effort to deliver the foundation for a comprehensive IG durability simulation tool is necessary to address advancements needed to meet current and future building envelope energy performance goals. This need is based upon the current lack of IG field failure data and the lengthy field observation time necessary for this data collection. Ultimately, the simulation program is intended to be used by designers throughout the current and future industry supply chain. Its use is intended to advance IG durability as expectations grow around energy conservation and with the growth of embedded technologies as required to meet energy needs. In addition the tool has the immediate benefit of providing insight for research and improvement prioritization. Included in the simulation model presentation are elements and/or methods to address IG materials, design, process, quality, induced stress (environmental and other factors), validation, etc. In addition, acquired data is presented in support of project and model assumptions. Finally, current and suggested testing protocol and procedure for future model validation and IG physical testing are discussed

Probing Chemical Dynamics Near Electrode Surfaces with U1tramicroelectrodes

This thesis describes work carried out to observe the dynamics of diffusion layer growth near electrode surfaces. For the first time, these processes are observed within 1 µm of an electrode. This is accomplished by positioning an ultramicroelectrode near an electrode surface with a scanning tunneling microscope. A bipotentiostat is integrated with the scanning tunneling microscope to allow potential control of the sample cell, permitting independent control of both the electrode substrate and the ultramicroelectrode tip potentials. The response of the diffusion layer to potentiostatic and galvanostatic stimulus of the substrate is described. The responses to the stimulus in the absence of coupled chemical reactions are shown to agree well with theory. The observed effects of a coupled chemical reaction are also reported and compared to the responses generated from a simulation program. Good agreement of the experimental data to the simulated data is shown, which demonstrates the ability of the instrument to study homogeneous kinetics.</p