This research developed a dynamic activated sludge model (ASM) to better describe the overall removal of organic substrate, quantified as chemical oxygen demand (COD), from A-stage high rate activated sludge (HRAS) systems. This dynamic computer model is based on a modified ASM1 (Henze et al., 2000) model. It was determined early in the project that influent soluble COD, which is normally represented by a single state variable in ASM1, had to be subdivided into two state variables (SBs and SBf, or slow and fast fractions) to simulate the performance of A-stage systems. Also, the addition of state variables differentiating colloidal COD from suspended COD was necessary due to short hydraulic residence times in A-stage systems which do not allow for complete enmeshment and bioflocculation of these particles as occurs in conventional activated sludge systems (which have longer solid retention times and hydraulic retention times). It was necessary to add several processes (both stoichiometry and kinetic equations) to the original ASM1 model including heterotrophic growth on both soluble substrate fractions and bioflocculation of colloidal solids. How to properly quantify heterotrophic growth on SBs and SBf resulted in two separate approaches with respect to process kinetic equations. In one approach the SBf was metabolized preferentially over SBs which was only utilized when SBf was not available. This is referred to as the Diauxic Model. In the other approach SBf and SBs were metabolized simultaneously, and this is referred to as the Dual Substrate Model. The Dual Substrate Model calibrated slightly better than the Diauxic Model for one of the two available pilot studies data sets (the other set was used for model verification). The Dual Substrate A-stage model was used to describe the effects of varying specific operating parameters including solids retention time (SRT), dissolved oxygen (DO), influent COD and temperature on the effluent COD:N ratio. The effluent COD:N ratio target was based on its suitability for a downstream nitrite shunt (i.e. nitritation/denitritation) process. In the downstream process the goal is to eliminate nitrite oxidizing bacteria (NOB) from the reactor while selecting for ammonia oxidizing bacteria (AOB). The results showed that a low SRT (< 0.25 d) can produce high effluent substrates (SB and CB), and elevated COD:N ratios consistent with NOB out-selection downstream, the HRAS model was able to predict the measured higher fraction of CB in the A-stage effluent at lower SRTs and DO concentrations, and to achieve the benefits of operating an A-stage process, while maintaining an effluent COD:N ratio suitable for a downstream nitritation/denitritation process, an A-stage SRT in the range of 0.1 to 0.25 d should be maintained. This research also included an analysis of A-stage pilot data using stoichiometry to determine the bio-products formed from soluble substrate removed in an A-stage reactor. The results were used to further refine the process components and stoichiometric parameters to be used in the A-stage dynamic computer model, which includes process mechanisms for flocculation and enmeshment of particulate and colloidal substrate, hydrolysis, production of extracellular polymeric substances (EPS) and storage of soluble biodegradable substrate. Analysis of pilot data and simulations with the dynamic computer model implied (indirectly) that storage products were probably significant in A-stage COD removal.

Lichens are among the most prominent and successful life forms of metal-rich habitats, including ultramafic rocks and soils; however, research on lichens of ultramafic habitats is limited, especially on the North American continent. A review of the published literature on lichens of ultramafic substrates in North America yielded a total of 437 lichen species reported from ultramafic rocks and soils. Lichen assemblages of ultramafic substrates vary in composition and are dominated by acidophytic (low pH preferring) taxa with a minor, but consistent, basiphytic (high pH preferring) component. Species lists from ultramafic habitats in different geographic regions varied widely, suggesting that factors unrelated to substrate, such as climate, have a large effect on lichen assemblage composition. However, several studies showed clear differentiation between lichen composition on nearby or adjacent ultramafic and nonultramafic habitats, suggesting that ultramafic substrates harbor regionally unique lichen assemblages. In a regional community ecology study, we sampled lichen biotas of eight ultramafic and eight sandstone outcrops along a 70 km maritime influence gradient in order to test three hypotheses: 1) a substrate effect hypothesis that saxicolous lichen communities of ultramafic and sandstone outcrops are compositionally distinct; 2) a maritime gradient hypothesis that coastal and inland communities are compositionally distinct; and 3) a maritime moderation hypothesis that coastal ultramafic and sandstone communities are more similar than those of inland ultramafic and sandstone. Relationships between lichen communities and abiotic variables were analyzed using perMANOVA. Ultramafic communities showed significant differentiation from sandstone communities in the study area. A total of 134 taxa were recorded - 81 taxa from ultramafic outcrops and 100 taxa from sandstone, with 47 taxa found on both rock types. Ultramafic outcrops were characterized by greater similarity between samples, lower lichen cover, larger differences in cover between north and south aspects, and higher abundance and diversity of cyanolichen taxa relative to sandstone. Coastal, intermediate, and inland communities were compositionally distinct from one another, and sandstone and ultramafic assemblages were significantly differentiated in all coastal distance groups. This study is one of few to quantitatively examine lichen communities of two rock types, and is unique in that it does so at a regional scale. These results add to our understanding of the interactive roles of substrate and maritime influence in lichen community assembly.

In the last 15 years, an immense amount of research has gone into developing high efficiency Gallium Nitride based light emitting diodes (LED). These devices have become increasingly popular in LED displays and solid state lighting. Due to the large difference in refractive index between GaN and Air, a significant amount of light reflects at the boundary and does not escape the device. This drawback decreases external quantum efficiency (EQE) by minimizing light extraction. Scientists and engineers continue to develop creative solutions to enhance light extraction. Some solutions include surface roughening, patterned sapphire substrates, and reflective layers. This study proposes to increase external quantum efficiency and optimize light extraction efficiency of several LED structures using finite difference time domain analysis (FDTD). The structures under investigation include GaN based LEDs with nanoscale top gratings, patterned sapphire substrates in combination with SiO2 nanorod arrays, and reflective surfaces below and above the sapphire substrate. First, we optimize GaN based nanoscale top gratings and increase light extraction by 17.8%. Next, we simulate ITO based top gratings and enhance light extraction by 40%. Third, we optimize patterned sapphire substrate period and width and the vertical position of a SiO2 nanorod array. We achieve as high as 51.8% improvement in light extraction. Finally, we increase light extraction by 160% with the use of a silver reflection layer.

Vascular endothelial growth factor (VEGF) is required for the development, growth and survival of blood vessels. Endothelial cell behavior is altered by cell substrate stiffness, suggesting that VEGF activity might also be influenced by cell-substrate mechanics. We studied VEGF binding, internalization, and signaling as a function of substrate stiffness using endothelial cells cultured on fibronectin (fn) linked polyacrylamide gels. Individual cell analysis of VEGF-induced calcium fluxes in endothelial cells on various stiffness extracellular matrices (ECM) revealed heterogeneity in our cell population that would have been lost using population based averaging. Cluster analysis of individual cells identified two key groups of reacting cells- a minor fraction of highly reactive cells and the bulk of the cells with minimal activation. At subsaturating VEGF doses, highly active cells were phenotypically smaller and thinner than the bulk population. Overall, cells on our softest substrates (4 kPa) were most sensitive to VEGF. To better understand the mechanisms underlying the changes in VEGF signaling due to stiffness, we explored how matrix binding of VEGF and tethering of cells to the matrix modulates VEGF processing. VEGF-ECM binding was enhanced with heparin pre-treatment, which exposed a cryptic VEGF binding site in the fn ECM. Cell produced ECM on the softest substrates were least responsive to heparin, but the cells internalized more VEGF and showed enhanced VEGF signaling compared to cells on all other substrates. Inhibiting VEGF-matrix binding with sucrose octasulfate decreased cell-internalization of VEGF in all conditions. β1 integrin, which connects cells to fn, modulated VEGF uptake in a stiffness dependent fashion. β1 protein levels were consistent with stiffness, yet cells on hard surfaces showed greater decreases in VEGF internalization than cells on softer matrices after β1 inhibition. Stiff matrices facilitate the unfolding of fn, which may reduce the binding capacity of β1 integrin. Thus a greater proportion of activated β1 integrin may be sensitive to inhibition in the stiff condition as compared to the soft. Ultimately, through analysis of individual and population-based VEGF-cell responses to stiffness, this study provides insight into how signaling dynamics, cell heterogeneity, and microenvironment influence tissue regeneration and response to injury and disease.

No description available.

<p> A thin film thickness monitor has been designed and constructed based on the "mass loading" effect of a resonant quartz crystal. A 6.0 MHz Y-cut crystal, having a theoretical "mass determination sensitivity" of 8.15x10^7 Hz. - cm^2/gm, serves as the sensor element. This sensitivity can be closely approached in practice if the entire active area of the quartz plate is exposed to the evaporant stream. However, due to source, substrate and crystal geometry the "effective" sensitivity of the monitor is only 0.433 of the above value. </p> <p> Both film thickness and deposition rate can be measured by the monitor in terms of equivalent frequency changes. The actual thickness and rates depend upon the density of the evaporant. In the case of silver (density 10.5 gm/cm^3), the monitor measures average thicknesses from several (oA) to 1.36 microns in one single deposition. Each crystal can be used to monitor a total of 4.5 microns of silver before replacement. Deposition rates for silver can be measured from as low as 0.l (oA)/sec to 1360 (oA)/sec. </p> <p> By combining the thickness monitor with apparatus for controlled evaporation, a system was set up which can control film thickness to within 2% and deposition rate to within 5%. </p> / Thesis / Master of Engineering (MEngr)

<p> An assemblage of coral skeletons of the species Desmophyllum cristagalli were obtained from the top of Orphan Knoll, 550 km northeast of Newfoundland, from depths of approximately 1600 and 1800 m. The corals were observed for their macro- and micro-boring assemblages, and the boring morphologies documented, using binocular and scanning electron microscopy. Samples of coral were embedded with resin and etched for examination of the micro-boring assemblages.</p> <p> The largest volumetric amount of skeletal material removed was by sponges forming Entobia. This further corroborates the assumption that various species of boring sponges are distributed ubiquitously throughout a wide bathymetric range.</p> <p> Four distinct fungal forms were found, two tubular forms interpreted to be hyphal filaments and two bulbous forms interpreted to be sporangia. These forms were described on the basis of their shape, size, mode of branching, association with other structures and texture. They were then compared to other micro-boring assemblages found in previous studies from various bathymetric ranges. Some forms described in this study were found to be similar to forms described in other studies. Other forms in this study were not found to be documented. It is suggested, therefore, that certain forms, as well as low ichnodiversity, may indicate deeper water environments.</p> <p> Destructive micritization structures were also found in resin casts as well as in thin section. The extent of micritization may indicate the intensity of the parameters at the substrate that affect carbonate dissolution, such as CaCO3 and CO2 concentrations, pH, temperature, and salinity. It would therefore indicate the ambient water conditions at the substrate. If a sufficiently large database could be obtained, as well as distinct separation of the parameters responsible for carbonate dissolution, micritization may be used in a mapping of the carbonate compensation depth through time and depth ranges.</p> / Thesis / Bachelor of Science (BSc)

There is a common belief that children compared with adults are at a greater risk for exercise-induced heat illness. However, a limitation of previous studies involves different exercise intensities used in the comparison between children and adults. Dehydration impairs aerobic performance, but its effects on strength are not well understood. Sports drinks are often used as ergogenic aids. There is some evidence to suggest children have a greater reliance on exogenous carbohydrate compared to adults, which could require special considerations when children exercise in the heat. The overall purpose of this thesis was to compare physiological and metabolic responses during exercise in the heat between boys and men. Three studies were conducted to 1) compare the thermoregulatory responses of boys and men exercising in the heat at a fixed absolute metabolic heat production or a fixed metabolic heat production per unit of body mass; 2) compare the effects of 2% hypohydration or, euhydration with and without carbohydrate ingestion during exercise in the heat on subsequent strength in boys and men; and 3) examine the effects of exogenous carbohydrate on endogenous metabolism in boys and men exercising in the heat. Age and body size differences between boys and men did not influence thermoregulatory responses at a fixed metabolic heat production per unit of body mass. No differences in strength were observed among trials. When exercising in the heat, the relative contribution of ingested carbohydrate and endogenous substrate to total energy yield were not different between groups. These findings together have practical implications for boys and men who exercise in the heat. Specifically, moderate exercise in the heat is equally safe for boys and men. The effects of hypohydration and a carbohydrate drink compared to water on muscle strength performance following exercise in the heat are minimal. An important practical application is that carbohydrate intake spared endogenous fuels during exercise in the heat in both groups. / Thesis / Doctor of Philosophy (PhD) / Children may not adapt to temperature extremes as effectively as adults. Thermoregulatory differences may be due to variable exercise intensities prescribed in available child-adult comparisons. Dehydration affects aerobic performance, but its effects on strength are not well understood. Sports drinks are often used to offset dehydration and improve performance; however, the body may have a harder time using sugar drinks when exercising in the heat. The purpose of this thesis was to compare bodily responses of boys and men during exercise in the heat. Our findings have important practical implications for boys and men who exercise and play sports in hot temperatures. Specifically, exercise in the heat is equally safe for boys and men. The effects of hypohydration and a sports drink on muscle strength performance following exercise in the heat are minimal. Finally, although exercise in the heat may affect the use of a sugar drink, boys and men may use this drink to improve aerobic performance, while maintaining hydration levels.

The research described here encompasses several different aspects of lithium ion battery operation including deep eutectic electrolytes, manganese trapping evaluation, silicon monoxide anodes, and in-situ NMR development under both static and spinning conditions. Individually, the results of these investigations as contained within the corresponding chapters contribute valuable insight. Collectively, they represent a snapshot into the numerous different ways in which nuclear magnetic resonance spectroscopy is applicable to lithium ion battery characterization. For instance, the deep eutectic electrolytes thus studied were amenable to diffusion coefficient characterization via the 1H, 7Li and 19F nuclei. This provided dynamical information on the anion, cation and neutral component and lent itself well towards parameterization of molecular dynamics simulations. The results thus obtained were useful in describing this relatively understudied class of electrolytes. Another example is that of the evaluation of manganese trapping. In this context 7Li NMR measurements were used to investigate the competitive inhibition of manganese trapping in crown ethers by lithium. Candidate crown ethers were thus evaluated for their ability to trap Mn2+ and Mn3+ in a lithium rich environment. Given the detrimental effects that manganese dissolution from cathode materials has on cycle life performance, the NMR enabled assessment of the appropriate chelating agents had identifiable importance. Additionally described was the progress made with silicon monoxide anodes supported on cellulosic substrates. The high active material loadings achieved, while also intriguing from a performance perspective, enabled 29Si MAS-NMR and 7Li static in-situ NMR measurements. For the in-situ measurements in particular, a novel cell design was constructed to utilize the advantages of a cellulosic substrate in this context. This has also enabled preliminary work on a spinning in-situ design. / Thesis / Doctor of Philosophy (PhD)

Целью данной работы является исследование методов определения электродинамических параметров диэлектрических материалов. В ходе выполнения работы были рассмотрены основные методы измерения в области высоких, сверхвысоких и крайне высоких частот, а также реализованные измерительные комплексы, предлагаемые ведущими производителями измерительного оборудования. В результате выполненной работы был выбран и реализован метод измерения параметров диэлектрических материалов, разработано программное обеспечение, необходимое для реализации измерительного комплекса. По результатам работы были проведены практические измерения и сделаны выводы о применимости разработанного измерительного комплекса. Актуальность работы объясняется необходимостью использования значений электродинамических параметров диэлектрика при разработке электронных устройств. / Were investigated different methods of define electrodynamic properties of dielectric materials. During this work was illuminated main methods of material properties measurements in RF domain. Was developed program for measurement a permittivity of material using a waveguide and an air line using vector network analyzer. The results of this work were define permittivity of different materials and analysis those results with errors explanation.