No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

<p>Please email me at kdunn@celccocontrols.com to confirm receipt of my thesis.</p> <p>Thanks,</p> <p>Kayne</p> / <p>In current microelectronic interconnect technology, significant delay is incurred due to capacitances in the intermediate and global interconnect layers. To avoid capacitive effects optical interconnects can be used; however conventional technologies are expensive to manufacture. One method to address these issues is to make use of quantum confinement effects and states lying within the bandgap of the material to enhance luminescence in a CMOS compatible silicon based system. Thin SiCxNy films appear to be suitable to work as luminescent silicon based films due to their lower direct bandgap and chemical stability but have not yet been studied in great detail.</p> <p>This thesis is an exploratory work aiming to assess the suitability of SiCxNy films for the above applications and to identify future research areas. The films analyzed in this thesis were manufactured on the inductively coupled plasma-chemical vapour deposition reactor (ICP-CVD) at McMaster University. The ICP-CVD produces films of high uniformity by using a remote RF plasma and an arrangement of high vacuum pumps to attain a vacuum on the order of 10-7Torr.</p> <p>Several experimental techniques have been used to analyse the films. The complex index of refraction has been determined through the use of ellipsometry giving results typical of that of a-SiNx:H. The photoluminescence spectroscopy results show a large broad emission peak with at least one shoulder at higher energies. The precise luminescence mechanism(s) could not be identified though a strong relationship with the bonding state of nitrogen has been found. The composition and structure of the films, as determined through ion beam measurements, infrared absorption measurements, and transmission electron microscopy measurements demonstrate the formation of a two phase structure consisting of carbon rich clusters surrounded by a mostly silicon nitride matrix. These carbon rich regions have some graphitic character and act to dampen the luminescence.</p> / Master of Applied Science (MASc)

<p>The effect of pressure transients on the onset of intermittent dryout in upward annular flow was experimentally investigated in order to resolve the conflict between the observations drawn from two major data sets in the literature. A delay in time to the onset of dryout at the test section exit relative to the time predicted based on steady-state data was observed in the R-12 experiments of Celata et al (1988; 1991). Steady-state prediction methods were sufficient to predict the upstream progression of a pre-existing dryout front in the water experiments of Lyons and Swinnerton (1983). Steady state and pressure transient dryout experiments were performed using water with outlet pressures of 2 to 6 MPa and mass fluxes of 1000 to 2500 kg/m2/s in an electrically heated 1.32 m long 4.6 mm ID vertical Inconel 600 tube with depressurisation rates of up to 1.0 MPa/s. Transient experiments were performed with a small margin to dryout and with post-dryout initial conditions in order to test the hypothesis that these initial conditions influenced the onset of dryout during transients. The results of a comparison between the steady dryout data and two dryout prediction methods---the Biasi et al (1967) correlation and the 2006 CHF look-up table (Groeneveld et al, 2007)---were used to develop correction factor correlations to reduce systematic error when these methods were used to predict the transient time to dryout. These modified methods yielded mean predicted dryout delays of -0.1 and 1.5 s respectively with standard deviations of approximately 3 s. There was no statistically significant variation between the pre- and post-dryout initial conditions. Based on this result it was concluded that the initial conditions did not affect the observed time to dryout. The mean wall temperature exhibited a discontinuous decrease as the heat flux approached 92 to 95% of the dryout value. It was postulated that this was caused by a heat transfer regime change from liquid film evaporation to droplet evaporation based on the observations of Hewitt (1970), Doroschuk et al (1970) and Groeneveld (2011). For the range of conditions of the present work the onset of intermittent dryout (Groeneveld, 1986) was caused by deterioration of droplet evaporation heat transfer. Celata et al (1988) noted that in their pressure transient experiments the decrease in saturation temperature drove a rapid increase in the heat flux to the fluid. This was caused by the release of stored thermal energy as the test section wall cooled. Celata et al (1991) stated that the systematic dryout delay was observed for depressurisation rates greater than 0.2 MPa/s. Using Celata et al's (1988) pressure transient data it was concluded that the stored thermal energy transient did not influence the onset of intermittent dryout when rho_w c_pw L_w *(dT_sat/dt)<0.3*q''_a.</p> / Doctor of Philosophy (PhD)

To propose a methodology for the uncertainty estimation in water quality modeling as related to TMDL development, four Monte Carlo (MC) based techniques—single-phase MC, two-phase MC, Generalized Likelihood Uncertainty Estimation (GLUE), and Markov Chain Monte Carlo (MCMC) —were applied to a Hydrological Simulation Program–FORTRAN (HSPF) model developed for the Mossy Creek bacterial TMDL in Virginia. Predictive uncertainty in percent violations of instantaneous fecal coliform concentration criteria for the prediction period under two TMDL pollutant allocation scenarios was estimated. The average percent violations of the applicable water quality criteria were less than 2% for all the evaluated techniques. Single-phase MC reported greater uncertainty in percent violations than the two-phase MC for one of the allocation scenarios. With the two-phase MC, it is computationally expensive to sample the complete parameter space, and with increased simulations, the estimates of single and two-phase MC may be similar. Two-phase MC reported significantly greater effect of knowledge uncertainty than stochastic variability on uncertainty estimates. Single and two-phase MC require manual model calibration as opposed to GLUE and MCMC that provide a framework to obtain posterior or calibrated parameter distributions based on a comparison between observed and simulated data and prior parameter distributions. Uncertainty estimates using GLUE and MCMC were similar when GLUE was applied following the log-transformation of observed and simulated FC concentrations. GLUE provides flexibility in selecting any model goodness of fit criteria for calculating the likelihood function and does not make any assumption about the distribution of residuals, but this flexibility is also a controversial aspect of GLUE. MCMC has a robust formulation that utilizes a statistical likelihood function, and requires normal distribution of model errors. However, MCMC is computationally expensive to apply in a watershed modeling application compared to GLUE. Overall, GLUE is the preferred approach among all the evaluated uncertainty estimation techniques, for the application of watershed modeling as related to bacterial TMDL development. However, the application of GLUE in watershed-scale water quality modeling requires further research to evaluate the effect of different likelihood functions, and different parameter set acceptance/rejection criteria. / Ph. D.

Constitutive relationships are developed to describe the water transport characteristics of the gas diffusion layer (GDL) of proton exchange membrane fuel cells (PEMFCs). Additionally, experimental fixtures and procedures for the determination of the constitutive relationships are presented. The water transport relationships are incorporated into analytical models that assess the impact of the water transport relations and that make PEMFC performance predictions. The predicted performance is then compared to experimental results. The new constitutive relationships are significantly different than the currently popular relationships used in PEMFC modeling because they are derived from experiments on actual PEMFC gas diffusion layer materials. In prior work, properties of the GDL materials such as absolute permeability, liquid water relative permeability, porosity, and capillary behavior are often assumed or used as adjustment parameters in PEMFC models to simplify the model or to achieve good fits with polarization data. In this work, the constitutive relations are not assumed but are determined via newly developed experimental techniques. The experimental fixtures and procedures were used to characterize common GDL materials including carbon papers and carbon cloths, and to investigate common treatments applied to these materials such as the bulk application of a hydrophobic polymer within the porous structure. A one-dimensional model is developed to contrast results based on the new constitutive relations with results based on commonly used relationships from the PEMFC literature. The comparison reveals that water transport relationships can have a substantial impact on predicted GDL saturation, and consequently a significant impact on cell performance. The discrepancy in saturation between cases can be nearly an order of magnitude. A two-dimensional model is also presented that includes the impact of the compressed GDL region under the shoulder of a bipolar plate. Results show that the compression due to the bipolar plate shoulder causes a significant increase in liquid saturation, and a significant reduction in oxygen concentration and current density for the paper GDL. In contrast, compression under the shoulder has a minimal impact on the cloth GDL. Experimental inputs to the 2-D model include: absolute permeability, liquid water relative permeability, the slope of the capillary pressure function with saturation, total porosity, GDL thickness, high frequency resistance, and appropriate Tafel parameters. Computational polarization curve results are compared to experimental polarization behavior and good agreement is achieved. / Ph. D.