No description available.

As wind energy penetration levels increase, there is a growing interest in using storage devices to aid in managing the fluctuations in wind turbine output power. Vanadium-Redox batteries (VRB) and Lithium-Ion (Li-Ion) batteries are two emerging technologies which can provide power smoothing in wind energy systems. However, there is an apparent gap when it comes to the data available regarding the design, integration and operation of these batteries in wind systems. This thesis presents suitable battery electrical models which will be used to assess system performance in wind energy applications, including efficiency under various operating conditions, transfer characteristics and transient operation. A design, sizing and testing methodology for battery integration in converter based systems is presented. Recommendations for the development of operating strategies are then provided based on the obtained results.

Extremozymes are enzymes produced by microorganisms that live in extreme habitats. Due to their higher stability, extremozymes is attracting interest as biocatalysts in various industrial processes. In this context, carbohydrate-active extremozymes can be used in various processes relevant to the paper, food and feed industry. In this thesis, the crystal structure, biochemical characterization and the capacity to synthesize prebiotic galacto-oligosaccharides (GOS) were investigated for a β-glucosidase (HoBGLA) from the halothermophilic bacterium Halothermothrix orenii. The wild-type enzyme displays favorable characteristics for lactose hydrolysis and produces a range of prebiotic GOS, of which β-D-Galp-(1→6)-D-Lac and β-D-Galp-(1→3)-D-Lac are the major products (Paper I). To further improve GOS synthesis by HoBGLA, rational enzyme engineering was performed (Paper II). Six enzyme variants were generated by replacing strategically positioned active-site residues. Two HoBGLA variants were identified as potentially interesting, F417S and F417Y. The former appears to synthesize one particular GOS product in higher yield, whereas the latter produces a higher yield of total GOS. In Paper III, the high-resolution crystal structure and biochemical characterization of a hemicellulase (HoAraf43) from  H. orenii is presented. HoAraf43 folds as a five-bladed β-propeller and displays α-Larabinofuranosidase activity. The melting temperature of  HoAraf43 increases significantly in the presence of high salt and divalent cations, which is consistent with H. orenii being a halophile. Furthermore, the crystal structures of a thermostable tetrameric pyranose 2-oxidase from Phanerochaete chrysosporium (PcP2O) were determined to investigate the structural determinants of thermostability (Paper IV). PcP2O has an increased number of salt links between subunits, which may provide a mechanism for increased stability. The structures also imply that the N-terminal region acts as an intramolecular chaperone during homotetramer assembly. / <p>QC 20150429</p>

No description available.

No description available.

Despite the long-term economic and environmental benefits of cellulosic biofuel production, low rates of cellulose utilization and products syntheses are major techno-economical barriers to the commercialization. Optimized medium composition and low-cost nutrient source could greatly enhance the feasibility of large-scale biofuels synthesis by direct cellulose fermentation using a consolidated bioprocessing (CBP) approach. This study developed an improved growth medium for Clostridium thermocellum, an excellent cadidate for CBP that utilizes cellulose to produce ethanol, hydrogen, and other value-added biochemicals. An experimental design to determine the importance of nutrient components and concentrations on H2 and ethanol production from cellulose by C. thermocellum initially considered seven growth nutrients. Three most significant components - α-cellulose, yeast extract, and magnesium chloride were investigated in detail for their influence on rates and yields of H2 and ethanol production during cellulose fermentation by C. thermocellum. To explore individual and interactive effects of these nutrients on ethanol and hydrogen (H2) production, a central composite face-centered design and the response surface methodology was applied to predict optimum nutrient compositions for H2 and ethanol production. Experimental verification of predicted optima produced about 3-fold and 4-fold more H2 and ethanol respectively compared with the reference medium. These small-scale results were successfully verified in large-volume (7L), atmospheric cultures. Irrespective of culture conditions, relative improvement in rates and productivities of H2 and ethanol in optimized medium compared with reference medium were consistent with small-volume cultures. Various ethanol distillery co-products were tested for their potentials to replace expensive medium ingredients. Medium prepared with these co-products show excellent ability to suppport cell-growth and production of ethanol and H2 at concentrations equivalent to those generated from the reagent grade medium. Utilization of these low-cost nutrient sources to replace expensive reagent ingredients may potentially contribute to the viability of both grain-based ethanol and cellulosic biofuels. With medium optimization, scale-up and use of low-cost nutrient sources, this study represents one of the very few systematic research approaches to improve direct bioconversion of cellulosic biomass into biofuels.

Sugar Maple (Acer saccharum Marsh.) is a very important tree species and is known not only for its sap in the production of maple syrup, but also for its superior hardwood quality and popular ornamental properties. In the effort to improve the diversity of the hardwood tree species in Manitoba, an effective propagation method for sugar maple is needed. The study tested several propagation techniques namely in vitro shoot organogenesis, induced embryo conversion and rooting of greenwood cuttings. Shoot multiplication was achieved using bud and embryo explants, however the rate of shoot production was very low implying that the culture conditions required some optimizations. Dormant isolated embryos were induced to germinate and convert into whole plants in vitro, eliminating the need for long stratification period. The study found the highest embryo conversion frequencies by the addition of cytokinin 6-benzylaminopurine (BAP) at 0.5-1.5 mg/L or thidiazuron (TDZ) at 0.01 mg/L into the culture medium. Greenwood cuttings of several hardy cultivars, including ‘Jefcan’, ‘Bailsta’ and ‘Green Mountain’ were compared for rooting capacity. In 2008, cutting type, rooting hormone and collection time were found to significantly influence rooting. In the following year, the study was expanded to compare different rooting conditions, using peat-perlite mix in fog system, sand beds under intermittent misting, and commercial peat plugs under automated misting system. Rooting was improved by selecting for medial-type cuttings and by promoting cutting survival through the the use of peat-based rooting medium and the maintenance of cool temperatures during the rooting period. The application of auxin did not increase rooting frequency of ‘Jefcan’ cuttings, but considerably improved the quality of roots produced, which may affect cutting survival upon transplantation.

No description available.

No description available.

No description available.