Nitric Oxide (NO) has been detected in the expiratory air of normal animals and human subjects. Recent experiments revealed that expiratory NO production rises during exercise and correlates well with O$ sb2$ consumption and heart rate. Whether or not physical conditioning influences expiratory NO output production remains unclear. In this study, NO concentration in expired gas was measured in 18 healthy male volunteers subdivided into 3 groups (sedentary, intermediate, athletes) based on their state of physical conditioning. Measurements were taken at rest and during two steady-state exercise bouts on a bicycle ergometer designed to elicit VO$ sb2$ of 1 and 2 1/min with the athletes performing an additional bout at VO$ sb2$ of 4 1/min. In the sedentary and intermediate groups, expired NO concentrations declined significantly with increasing VO$ sb2.$ In contrast, expired NO levels declined only slightly with increasing VO$ sb2$ in athletes. At a VO$ sb2$ of 2 1/min, expired NO concentrations were significantly higher in athletes compared with the other groups. When correlated with V$ rm sb{E},$ expired NO concentrations declined linearly with the increase in $ rm V sb{E}$ in sedentary and intermediate groups but not in the athletes. Only the athletes had a significant linear increase in NO output (expired NO x V$ rm sb{E})$ with increasing VO$ sb2$ (p $<$ 0.001). These results support the notion that physical conditioning increases expiratory NO output during exercise. We speculate that the rise in expiratory NO output in athletes might be due to increased vascular and/or epithelial production of NO. Enhanced vascular NO production may be the result of increased shear stress and/or upregulation of endothelial NO synthase gene expression.

Tungsten doped tantalum oxide films on titanium substrates were investigated for use as anodes in the electrochemical disinfection of wastewater (measured through e. coli inactivation). A sol-gel method for fabricating these films was developed that allowed for control of both the doping concentration (through volumes of tantalum and tungsten ethoxide added to the solutions), and the thickness (through the number of layers applied). The morphology and composition of these films were investigated using SEM and EDX mapping; the morphology was found to be connected to the fabrication heating procedure. Three different doping concentrations (0%, 8% and 14% tungsten by volume of added metals) were investigated for: 1) electrochemical activity; 2) long-term stability; and 3) disinfection capabilities. The 14% samples demonstrated the highest conductivity (0.06μS/cm), good long-term stability (verified using ICPMS, SEM and EDX analysis) and the best electrochemical activity for removal of e. coli (based on wastewater tests).

Tungsten doped tantalum oxide films on titanium substrates were investigated for use as anodes in the electrochemical disinfection of wastewater (measured through e. coli inactivation). A sol-gel method for fabricating these films was developed that allowed for control of both the doping concentration (through volumes of tantalum and tungsten ethoxide added to the solutions), and the thickness (through the number of layers applied). The morphology and composition of these films were investigated using SEM and EDX mapping; the morphology was found to be connected to the fabrication heating procedure. Three different doping concentrations (0%, 8% and 14% tungsten by volume of added metals) were investigated for: 1) electrochemical activity; 2) long-term stability; and 3) disinfection capabilities. The 14% samples demonstrated the highest conductivity (0.06μS/cm), good long-term stability (verified using ICPMS, SEM and EDX analysis) and the best electrochemical activity for removal of e. coli (based on wastewater tests).

Lithium cobalt oxide was synthesized by solid-state reactions and SPRAY-DRY method. Its investigation of the formation were perform of lithium and cobalt acetate, lithium and cobalt citrate, LiOH and Co(NO3)2· 6H2O mixtures in high-temperatures. Their formation was analyzed and with the help of the X-ray diffraction the structure of the products of the solid-state reactions was determined. The thermal processes, that take place during the synthesis, were analyzed with the help of differential-thermal analysis.

Understanding the relationship between the structure of materials and their properties allows for the development of new applications and technologies. Here the relationship between local structure and optical properties in several binary oxide glass systems containing zinc oxide was examined, in particular the relationship between structure, applied stress and induced birefringence in a glass. The empirical model introduced by Zwanziger and co-workers posits a negative correlation between the ratio of the bond length to coordination number in a glass and the induced birefringence; zinc oxide in this model is predicted to be exactly at the threshold between positive and negative birefringence and is thus of particular interest to investigate. XAFS and Raman spectroscopy were used to determine local structure while the Sénarmont compensator method, Abbe refractometry and spectroscopic ellipsometry were used to measure optical properties.

Poly(ethylene oxide) (PEO) is known for facilitating the electrospinning of biopolymer solutions, that are otherwise not electrospinnable. The objective of this study was to investigate the mechanism by which PEO enables the formation of whey protein isolate (WPI) electrospun fibers under different pH conditions. This investigation revealed that the addition of PEO increased the viscosity of WPI/PEO (10% w/w WPI; 0.4% w/w PEO) solutions. Difference in pH levels of the polymer solutions affected electrospinnability and fiber morphology. Acidic solutions resulted in smooth fibers (700 ± 105 nm) while neutral solutions produced spheres (2.0 ± 1.0 um) linked with ultrafine fibers (138 ± 32 nm). In comparison, alkaline solutions produced fibers (191 ± 38 nm) that were embedded with spindle-like beads (1.0 ± 0.5 um). Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analyses revealed that the native globular configuration of WPI was not altered under neutral conditions. By contrast, the electrophoresis and spectrometry data indicated that WPI was denatured and hydrolyzed under acidic conditions, which facilitated the formation of smooth fibers. C13 nuclear magnetic resonance (NMR) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopies showed that the increase random coil and a-helix secondary structures in WPI contributed to the formation of bead-less electrospun fibers. Also, C13 NMR analysis showed no evidence of chemical interaction between WPI and PEO. Scanning transmission electron microscopy coupled with energy dispersive X-rays (STEM-EDAX) revealed that WPI was uniformly distributed within WPI/PEO electrospun fibers. Observations by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) indicated that fibers possessed a solid core. All these findings suggested that PEO enables the formation of WPI/PEO electrospun fibers by entanglement/entrapment/deposition. Preliminary studies were conducted on hydroxypropyl methyl cellulose (HPMC). In the absence of PEO, HPMC enabled the formation of WPI electrospun fibers under acidic conditions (124 ± 46 nm). FTIR analyses indicated that there was no interaction between HPMC and WPI, suggesting that HPMC aided in the electrospinning of WPI fibers, also by entanglement/entrapment/deposition. Hence, HPMC and PEO aid in the electrospinning of WPI fibers by entanglement/entrapment/deposition, which can be manipulated by alterations in the protein configuration and solution properties. / Natural Sciences and Engineering Research Council (NSERC) of Canada and the Dairy Farmers of Ontario (DFO)

In an effort to better understand the impacts of nitrogen oxides (NOx) emissions from oil sands development on soils and vegetation, a laboratory experiment was designed, which mimicked the natural and reclaimed boreal forest environment found in the Fort McMurray area. The primary objective of this research was to examine the effects of various types and concentrations of NOx under a controlled laboratory study, and to provide recommendations and management strategies with respect to NOx deposition management. Findings indicated that, for some vegetation types, significant relationships exist between NOx treatment and vegetation height, biomass, and percent total nitrogen responses. Furthermore, some soil chemical parameters exhibited significant differences due to treatment and or soil depth, and some appeared to serve as better indicators of NOx deposition. Recommendations are made with respect to future research considerations and management strategies for NOx emissions including consideration of both eutrophication and acidification potential.

Research was performed on the development of metal-supported solid oxide fuel cell (SOFC) electrolytes by suspension and solution precursor plasma spraying (SPS and SPPS). Experiments were conducted to understand the effects of many plasma-, feedstock-, and substrate-related process parameters on the microstructure, permeability, and conductivity of the resulting coatings. Most work was performed with yttria-stabilized zirconia (YSZ), but samaria-doped ceria (SDC) was also considered. The plasma-to-substrate heat flux behaviour of the process is particularly relevant for producing dense electrolytes with low segmentation cracking. Heat flux profiles for various processing conditions were experimentally determined and then used to model temperature distributions in the electrolyte and substrate during deposition. The results showed a strong correlation between segmentation crack severity and the peak temperature difference between the electrolyte surface and the metal support during deposition. Building on these findings, two strategies were developed for improving electrolyte performance. The first strategy is to use a bi-layer electrolyte structure, in which one layer is dense but has segmentation cracks and the other layer is more porous but contains relatively few segmentation cracks. A cell with a bi-layer electrolyte achieved a peak power density of 0.718 W cm-2 at 750 °C using hydrogen as fuel. The second strategy involves reducing the thickness and roughness of the electrode on which the electrolyte is deposited, which first required the development of improved metal supports. A thinner electrode reduces the thermal stresses that drive segmentation cracking and a smoother surface minimizes the formation of concentrated porosity. A cell with a 16 μm thick anode and a 21 μm thick electrolyte achieved an open circuit voltage (OCV) of 1.053 V, a series resistance of 0.284 Ω cm2, and a peak power density of 0.548 W cm-2 at 750 °C using hydrogen as fuel. A separate cell with a 28 μm thick electrolyte achieved an OCV of 1.068 V. At the end of the thesis, cell performance is compared to that of state-of-the-art cells produced in other facilities and using other production methods.

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No description available.