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Hydraulic Fracturing: A Look at Efficiency in the Haynesville Shale and the Environmental Effects of FrackingJackson, Emily Celeste 02 April 2014 (has links)
Hydraulic fracturing has become a hot topic in Americas growing, domestic, oil and natural industry. This new technology has provided an economic way to extract resources from tight oil and gas shale formations found deep underground, but this new way of drilling does not come without environmental and human health effects. Among these health effects are water usage, water quality, and air quality. In this paper, data from Frac Focus.org was used to get the average amount of water used per well, and the average amount of chemicals, and what those chemicals are, for each well in the Haynesville Shale. An extensive literature review was used to get average air emission data from drilling and hydraulic fracturing. Data from the Louisiana Department of Natural Resources SONRIS was used to find average drilling statistics associated with Haynesville Shale wells and used to determine drilling and hydraulic fracturing efficiency. These parameters were then used estimate air emissions, water usage, and chemical use in the Haynesville Shale. It was found that on average an unconventional well in the Haynesville Shale used 6.5 million gallons of water. The top three chemicals used in fracking fluid were found to be: Hydrochloric Acid, Phenol, and Quaternary Ammonia Salts, used at an average concentration of 0.21%, 0.086%, and 0.02%, respectively. Air emissions from unconventional drilling processes were estimated for NOx, CO, VOC, PM, SOx, CO2, and CH4. Overall, the drilling process in the shale was found to emit the most amount of emissions, except for CH4 where fracturing emitted the most. Lastly, using the drilling parameters and water use calculations, evidence was shown that learning by doing was taking play in the Haynesville Shale and that efficiency, in some aspects of the well development activities, was being achieved.
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Characterization of nickel hydroxide sludge using the variable pressure SEMRobertson, Kevin January 2004 (has links)
Acid mine drainage lime treatment sludge is characterized with the variable pressure scanning electron microscope. The major components are shown to be detrital material such as silicates and clay minerals and neutralization products such as gypsum and metal hydroxides. / X-ray mapping and progressive sludge leaching experiments are performed to locate the major nickel bearing species. Progressive leaching was performed for two hours at pH 4, 3.5, and 3. It is observed that there is incomplete nickel extraction for all leach conditions. X-ray mapping establishes that the remaining nickel is due to minor amounts of Ni/S and Ni/O and more significantly colloidal sized nickel-silicon-aluminum complexes; which seem to result from neutralization. / Charge contrast imaging was also considered for characterization. It was studied on the mineral gibbsite to establish optimum working conditions for maximum contrast. Pressure, working distance, bias, scan rate and beam current are varied independently while the specimen current was monitored. Maximum contrast is shown to occur consistently at a specimen current of 3 nA. This implies that the user can operate over a wide range of conditions as long as the specimen current is maintained at its optimum value. This technique is then applied to the analysis of precipitated nickel hydroxides. Charge contrast proved not too informative because the particles are too small. Large electron doses at high magnifications can mask the subtle variation in local charging.
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Restorative learning, restorative living : poetic inquiry as embodied ecologyHouwer, Rebecca. January 2006 (has links)
We live during a period of unparalleled, human-caused, systemic disruption of the biosphere and the very processes that sustain life on Earth. As such, it is important that we critically assess the beliefs and corresponding actions that have led us to our present state. By allowing destructive habits of being to disintegrate, we can then direct our intellectual, emotional, individual, and collective energy toward eco-social restoration. Destructive practices can be learned and unlearned. The following essay considers how the convergence of ecological thought and poetic inquiry can support the learning of embodied and restorative cultural practices. Responding to the present state of cultural disconnection from life's organic cycles, it strives to "re-story," in form and content, the dominant Western cultural narrative. Eco-social restoration is discussed within the context of popular environmental thought, traditional education, eco-poetry, and the politics of place.
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Development and validation of a novel surface emission sampler for in-situ characterization of sources of indoor air pollution in non-industrial microenvironments : Soheil Rastan.Rastan, Soheil. January 2005 (has links)
Similar to passive exposure to cigarette smoke, building occupants, in homes and in offices, are passively exposed to volatile organic compounds that are being emitted form surfaces of interior finishes and furnishings. Identifying emissions from surfaces of interior finishes and furnishings requires in-situ sampling. Interior finishes and furnishings used in homes and offices are many and varied. Current available methods used for sampling surface emissions from interior finishes and furnishings require the use of environmental chambers in laboratory settings. The in-situ applications of these lab-based chambers are limited. A novel method for in-situ surface emission sampling is needed. This thesis presents the development and validation of a novel surface emission sampler, the Kappa. Emissions from an interior carpet sample were captured using three different samplers, an ASTM-based chamber, a Field and Laboratory Emission Cell (FLEC) and the novel Kappa. Results were compared qualitatively and quantitatively. Based on the results obtained, the Kappa and the FLEC were comparable in their relative responses with each other and against the ASTM chamber. The Kappa, however, sampled emissions in-situ, whereas the ASTM and the FLEC sampled emissions under laboratory settings. As an in-situ surface emission sampler, the Kappa was able to estimate the contribution of an interior finish such as a carpet to indoor air pollution in real indoor conditions. The Kappa could thus provide representative, appropriate and necessary field data that are required to justify implementation of site-specific remedial action. The latter would help reduce the burden of, and occupants' exposure to emissions from interior finishes and furnishings in non-industrial microenvironments.
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Shotgun proteomic analysis of Clostridium acetobutylicum during butanol fermentationSivagnanam, Kumaran January 2013 (has links)
Shotgun proteomic technology is a powerful characterization tool that can be used to investigate the global status of an organism at the molecular level. This dissertation presents the shotgun proteomic analysis of Clostridium acetobutylicum which is capable of converting different sugars present in the lignocellulosic biomass to acetone, butanol, and ethanol through fermentation. In the first study, glucose was found to be the preferred substrate of C. acetobutylicum for butanol production and the subsequent shotgun proteomic analysis identified over 400 proteins using a 6-step mass spectrometry based shotgun proteomics approach. The identified proteins were used to construct a C. acetobutylicum protein interaction map which was the first report of pathways interaction network for C. acetobutylicum. The second study employed a 12-step shotgun proteomics approach and a total of 894 proteins were identified in C. acetobutylicum during butanol fermentation between glucose and xylose substrates. This study revealed significant changes in the proteomic profile of C. acetobutylicum involved in chemotaxis and flagellar mechanisms during butanol fermentation between glucose and xylose substrates. In the third study, the proteomic profile of C. acetobutylicum was analyzed between two different phases of butanol fermentation using xylose substrate. Interestingly, the C. acetobutylicum proteomic profile was found to be significantly different between the exponential growth and stationary growth phases, with proteins directly involved in the butanol production pathway found to be highly expressed in the exponential growth compared to the stationary phase. The final study of this dissertation reports the proteomic analysis of C. acetobutylicum during butanol fermentation using a glucose/xylose mixture. Over 800 C. acetobutylicum proteins were identified and compared with the previous studies. The comparative analysis revealed protein expression from C. acetobutylicum were lower in the glucose/xylose mixture when compared to the preferred glucose substrate for biochemical processes that are vital for fermentation, such as carbohydrate metabolism, butanol production pathway and chemotactic and motility behaviour. These findings provide an in-depth proteomic knowledge base of C. acetobutylicum fermentation and butanol production using the two major sugars present in lignocellulosic biomass. Furthermore, the data presented can be used to develop better fermentation monitoring systems to construct an optimized environment for butanol production and serves as a base for future molecular level butanol research. / La technologie de protéomique shotgun est un outil puissant de caractérisation au niveau moléculaire qui peut être utilisé pour l'investigation sur la situation globale d'un organisme. Cette thèse présente l'analyse protéomique shotgun du Clostridium acetobutylicum qui est capable de convertir les différents sucres présents dans la biomasse lignocellulosique en acétone, butanol et éthanol par fermentation. Dans la première étude, le glucose a été jugé le substrat préféré du C. acetobutylicum pour la production de butanol et l'analyse protéomique shotgun ultérieure a identifié plus de 400 protéines en utilisant l'approche protéomique shotgun basée sur une spectrométrie de masse de 6 étapes. Les protéines identifiées ont été utilisées pour construire une carte d'interactions proteinées du C. acetobutylicum qui était le premier rapport d'un réseau d'interaction protéine-protéine pour C. acetobutylicum. La deuxième étude a utilisé une approche de protéomique shotgun en 12 étapes et un total de 894 protéines ont été identifiées dans C. acetobutylicum pendant la fermentation du butanol entre les substrats glucose et xylose. Cette étude a révélé des changements significatifs dans le profil protéomique du C. acetobutylicum impliqués dans les mécanismes de chimiotactisme et flagellaires pendant la fermentation du butanol entre les substrats glucose et xylose. Dans la troisième étude, le profil protéomique du C. acetobutylicum a été analysé entre deux phases différentes de la fermentation du butanol en utilisant le substrat xylose. Fait intéressant, le profil protéomique du C. acetobutylicum a été jugé significativement différent entre les phases de croissance exponentielle et de croissance stationnaire, où les protéines directement impliquées dans la filière de production de butanol ont été trouvées être fortement exprimées dans la croissance exponentielle par rapport à la phase stationnaire. La dernière étude de cette thèse rend compte de l'analyse protéomique du C. acetobutylicum pendant la fermentation du butanol en utilisant un mélange de glucose/xylose. Plus de 800 protéines du C. acetobutylicum ont été identifiées et comparées avec les études antérieures. L'analyse comparative a révélé que l'expression des protéines du C. acetobutylicum était plus faible dans le mélange de glucose/xylose par rapport au glucose, le substrat préfère les processus biochimiques qui sont vitales pour la fermentation, tels que le métabolisme des glucides, filière de la production de butanol et les comportements chimiotactiques et de motilité. Ces résultats fournissent une connaissance approfondie de la protéomique de la fermentation du C. acetobutylicum et de la production de butanol en utilisant les principaux sucres présents dans la biomasse lignocellulosique. En outre, les données présentées peuvent être utilisées pour développer de meilleurs systèmes de surveillance de fermentation pour la construction d'un environnement optimisé pour la production de butanol et sert de base pour l'avenir de la recherche du butanol au niveau moléculaire.
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Evaluation of biochar soil amendments in reducing soil and water pollution from pathogens in poultry manureArief Ismail, Shoieb Akaram January 2013 (has links)
This project addresses concerns from the Canadian public about the quality of water in regions where many agricultural operations are located. Fecal coliforms are endemic in poultry and are difficult to eradicate from production facilities. Poultry manure is a reservoir of Campylobacter jejuni, Escherichia coli (including O157:H7) and Salmonella spp. Biochar, the charcoal produced from pyrolysis of biomass, is gaining global recognition due to its unique properties when applied as a soil amendment. Biochar could play an important role in controlling the mobility of pathogens in soil and water environment. Its half-life is estimated to be hundreds of years so it is expected that its role in reducing agricultural pollution could be very long-lasting, and hence very cost-effective.In this study we investigated the effectiveness of biochar in preventing the leaching of fecal coliforms into surface water. The target organisms in this study were Escherichia coli (E .coli) and total coliform. E. coli is widely recognized as the indicator organism for presence of fecal coliform and total coliforms to determine disinfection rate. The study was divided into two components, namely laboratory study and field study.In laboratory study, the effectiveness of three different types of biochar (variation based on production temperature, time and raw material) in adsorption and desorption of E. coli was studied. In adsorption test, a comparative analysis was carried out to understand the differences between biochar, soil amended biochar (soil to biochar ratio of 99:1) and un-amended soil in the removal of E. coli. The statistical analysis showed the adsorption of E. coli was significantly higher in the soil amended biochar treatment. The soil amended biochar and the un-amended soil treatments were further subjected to desorption to test their retention capacity. The statistical analysis showed that two types of soil amended biochars (slow pyrolysis biochar and fast pyrolysis biochar) retained E. coli significantly better. The adsorption capacity of biochar was directly proportional to its porosity and inversely proportional to its ash content. The two types of soil amended biochar were shortlisted based on sorption and retention capacity and were used as treatments in the field study.A sixty-day study was conducted using field lysimeters to evaluate the effectiveness of soil amended biochar in removing or reducing the leaching of fecal coliforms (E. coli) from poultry manure. Lysimeter with only soil was used as control and the shortlisted biochars (slow pyrolysis biochar and fast pyrolysis biochar) were used as treatments. In the biochar-amended treatments, the top 0.05 m of soil was amended with biochar in a proportion of 1:99 biochar:soil. Poultry manure was spread over the soil in all lysimeters. The lysimeters were protected from natural rainfall, and the simulated rainfall was applied as 4 events over a sixty day period. Both soil (3 sampling depths) and leachate samples were collected and analyzed at predetermined time intervals. In the experiment, E. coli and total coliform were found to leach down through the soil profiles, and their concentrations decreased with soil depth and time. The statistical analysis of soil samples and leachate showed that the concentration of E. coli in the treatments at the three sampling depths and in the leachate were significantly different from control (P ≤ 0.05), which is attributed to the effectiveness of the treatments in reducing the leaching of fecal coliforms. However, the concentration of total coliforms was significant (P ≤ 0.05) on certain intervals and insignificant in the others; this can be attributed to already present total coliforms in the soil system and effectiveness of the treatments to hinder coliform transport. Soil biochar amendment was thus seen to be effective in reducing the leaching of fecal coliforms through soil profiles and providing fecal coliforms free leachate. / Ce projet répond aux préoccupations du public canadien au sujet de la qualité de l'eau dans les régions où de nombreuses exploitations agricoles sont présentes. Les coliformes fécaux sont endémiques chez les volailles et sont difficiles à éradiquer des sites de production. Le biochar, un charbon produit par pyrolyse de la biomasse, gagne de plus en plus de reconnaissance à l'échelle mondiale en raison de ses propriétés uniques lorsqu'il est utilisé comme amendement de sol. Sa demi-vie est estimée à des centaines d'années. Par conséquent, son rôle dans la réduction de la pollution agricole pourrait s'étendre sur une longue période.Dans cette étude, nous examinons l'efficacité du biochar dans la prévention de la lixiviation des coliformes fécaux dans l'eau de surface. Les organismes ciblés dans cette étude sont Escherichia coli (E coli.) et les coliformes totaux. E. coli est reconnu comme étant l'organisme indicateur de la présence de coliformes fécaux et les coliformes totaux comme étant révélateur du taux de désinfection. L'étude est composée de deux parties, l'une effectuée en laboratoire et l'autre sur le terrain.Dans l'étude en laboratoire, l'efficacité d'absorption et de désorption d'E. coli de trois différents types de biochar a été étudiée. Par le moyen de tests d'adsorption, une analyse comparative a été effectuée afin de déterminer la différence entre du biochar pur, un sol amendé par du biochar et un sol non-amendé dans leur efficacité d'élimination d'E. coli. Les analyses statistiques ont montré que le biochar comme amendement du sol joue un rôle important dans l'adsorption d'E. coli.Le sol amendé par du biochar et le sol non-amendé ont ensuite été soumis à un test de désorption afin de tester leur capacité de rétention. Les analyses statistiques ont démontré que deux types de sol amendés de biochar (l'un issu de la pyrolyse lente et l'autre de la pyrolyse rapide) retenaient E. coli. La capacité d'adsorption du biochar s'est révélée être directement proportionnelle à sa porosité et inversement proportionnelle à sa teneur en cendres. Les deux types de biochars ont été sélectionnés et utilisés comme traitements dans l'étude de terrain. L'étude de terrain a été réalisée sur des lysimètres pendant soixante jours afin d'évaluer l'efficacité du biochar dans l'élimination et la réduction du lessivage des coliformes fécaux (E. coli) venant du fumier de volaille. Le témoin contenait seulement du sol et le biochar sélectionné (l'un issu de la pyrolyse lente et l'autre de la pyrolyse rapide) a été utilisé comme traitement. Le biochar a été mélangé avec 5 cm de sol en partant de la surface (rapport de sol a biochar de 99:1). Le fumier de volaille a été répandu sur le sol dans tous les lysimètres. Les lysimètres ont été protégés de la pluie afin de simuler l'irrigation. L'irrigation a été simulée en 4 événements au cours des soixante jours. Le sol (3 profondeurs d'échantillonnage) et les échantillons de lixiviat ont été prélevés et analysés à des intervalles temporels prédéterminés. Dans cette étude, E. coli et les coliformes totaux se sont infiltrés à travers les profils de sol, et leurs concentrations ont diminués avec le temps et la profondeur du sol. Les analyses statistiques (P ≤ 0.05) des échantillons de sol et des lixiviats ont montré que la concentration d'E. coli dans les traitements aux trois profondeurs et dans le lixiviat étaient différente du contrôle, ce qui est attribué à l'efficacité des traitements de réduction du lessivage des coliformes fécaux. Cependant, la concentration de coliformes totaux était significatif (P ≤ 0.05) sur certains intervalles et insignifiant sur d'autres, ce qui peut être lié a une présence antérieure de coliformes totaux dans le sol et a l'efficacité des traitements qui suggèrent un taux de désinfection efficace. Le sol amendé de biochar a donc été considéré comme étant efficace dans la réduction du lessivage des coliformes fécaux a travers les profils de sol.
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Impact of UV disinfection on the virulence and antibiotic resistance gene profile of Escherichia coli in municipal wastewater and its receiving watersYip Woon Sun, Melanie January 2013 (has links)
Fecal water contaminations have been known to cause severe disease outbreaks throughout the world, thus proper wastewater treatment can help to avoid them. Escherichia coli (E. coli) is a well-known microorganism that flourishes in the gut of warm-blooded animals and can cause disease, such as diarrhoea, urinary tract infection, dysentery-like illness, haemorrhagic colitis and neonatal meningitis. Previous studies have shown that the virulence gene profile of E. coli can accurately predict its in vivo pathogenicity in animal models. E. coli in municipal wastewaters was therefore used in this study as a model pathogenic microorganism to examine the effects of activated sludge and UV disinfection on its virulence and its antibiotic resistance gene profile. DNA microarrays were used to conduct genotyping. The virulence and antibiotic resistance gene profile of E. coli in the receiving waters impacted by the treatment plant were also investigated.E. coli isolates (540 in total) were collected in May 2011 from 6 locations at the Skyway Wastewater Treatment Plant (Burlington, Ontario) and the Hamilton Harbour, which is the receiving water body for the treatment plant's effluent. Samples were also collected from an avian-contaminated area to investigate a possible relationship between the pollution in the harbour and the pollution by wild birds and municipal effluents. Results showed that although UV disinfection decreased the E. coli counts by more than 2 logs, the percentage of E. coli with a pathogenic genotype in the surviving population had increased by almost 10%. The activated sludge system proliferated virulence and antibiotic resistance genes. 22.5% of all isolates were uropathogenic E. coli 6.7% incomplete extraintestinal pathogenic E. coli and 1.7% shiga-toxin associated E. coli. No strong correlation was found between the genotypes found in the treatment plant's effluent and the harbour samples. 40% of the treatment plant's isolates carried some antibiotic resistance genes with a higher proportion of isolates carrying multiple antibiotic resistance genes. The majority of the isolates (70%) did not carry any antibiotic resistance (AMR) genes. Most of the AMR genes detected corresponded to beta-lactams (20%), aminoglycosides (19.6%), tetracyclines (19.1%), phenicols (12.6%) and trimethoprim (11.5%). Also, results demonstrated that UV decreased (by 9%) the percentage of isolates that had multiple antibiotic resistance genes, while activated sludge increased this percentage (by 5%). No statistically significant difference was found in the distribution of the antibiotic resistance genes in the harbour samples or between the pathotypes and the presence of antibiotic resistance genes in any samples. / Dans le passé, plusieurs épidémies ont été causées par des eaux contaminées par des matières fécales. Le traitement des eaux usées municipales peut ainsi aider à éviter ces épidémies. Escherichia coli (E. coli) est un microorganisme qui vit dans l'intestin d'animaux à sang chaud. Ceux-ci peuvent causer des maladies, comme la diarrhée, les infections des voies urinaires, la dysenterie, la colite hémorragique et la méningite néonatale. Des études antérieures ont montré que le profil de gènes de virulence de la bactérie E. coli peut prédire avec précision sa pathogénicité in vivo dans des modèles animaux. Dans cette étude, E. coli a été utilisé comme un modèle de microorganisme pathogène pour examiner les effets de la désinfection par UV et des boues activées sur le profile de gènes de virulence et de résistance aux antibiotiques dans les eaux usées municipales. Les puces à ADN ont été utilisées pour effectuer le génotypage. Les effets de la station d'épuration sur le profil de gènes de virulence et de résistance aux antibiotique des E. coli retrouvées dans les eaux réceptrices, impacté par la station d'épuration, ont également été étudiés.Des isolats de E. coli (540 au total) ont été recueillies, en mai 2011, à partir de 6 emplacements à l'usine d'épuration d'eau Skyway (Burlington, Ontario) et du port d'Hamilton, qui est le plan d'eau récepteur pour les effluents de la station d'épuration. Des échantillons ont également été prélevés d'une zone contaminée par des oiseaux sauvages dans le but d'investiguer les liens entre la pollution dans le port d'Hamilton, la pollution par les oiseaux sauvages et les effluents de la station dépuration. Les résultats ont montré que, malgré que la désinfection par UV avait diminué les comptes d'E. coli par plus de 2 logarithmes, le pourcentage d'E. coli ayant un génotype pathogénique, dans la population survivante avait augmenté de près de 10%. Le système de boues activées avait proliféré les gènes de virulence et de résistance aux antibiotiques. 22,5% de tous les isolats étaient des E. coli uro-pathogénique, 6,7% des E. coli pathogénique extra-intestinaux et 1.7% des E. coli produisant de la Shiga-toxine. Aucune corrélation n'a été observée entre les génotypes trouvés dans les effluents de la station d'épuration et les échantillons du Hamilton Harbour. 40 % des isolats de l'usine d'épuration avait des gènes de résistance aux antibiotiques. Une plus grande proportion des ces isolats avait multiples gènes de résistance aux antibiotiques. La majorité des isolats (70%) n'avait pas des gènes de résistance aux antibiotiques. La plupart des gènes de résistance aux antibiotiques correspondent aux bêta-lactamines (20%), les aminosides (19,6%), les tétracyclines (19,1%), phénicols (12,6%) et le triméthoprime (11,5%). En outre, les résultats ont démontré que la désinfection par UV avait diminué de 9% le pourcentage d'isolats qui avait de multiples gènes de résistance aux antibiotiques, tandis que les boues activées avaient augmenté ce pourcentage de 5%. Aucune différence, qui était statistiquement significative, n'a été trouvée dans la distribution des gènes de résistance aux antibiotiques des échantillons provenant du port d'Hamilton ou entre les pathotypes et la présence de gènes de résistance aux antibiotiques dans les échantillons.
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On the prediction of power outputs in a microbial fuel cell employing Escherichia coli K12 as the biocatalystMadiraju, Kartik January 2013 (has links)
The lack of access to clean electricity and water in developing nations has given importance to the development of low-cost, widely applicable energy technologies. Microbial fuel cells are being explored as potential sources of clean electricity. A microbial fuel cell (MFC) is a device, in which bacteria produce electrons by oxidizing organic material, which are shuttled from the anode to the cathode, producing a current; the only byproducts of this process are respiratory waste in the form of water and carbon dioxide. Although significant advances have been made in optimizing MFCs for power output, power outputs are not always reproducible, and most importantly, MFC performance is not yet predictable under different operating conditions. These two challenges are prerequisites to the commercialization of MFC technology. In this study, a single-chamber MFC employing E.coli K12 as the biocatalyst was used to optimize power outputs and operating conditions, and demonstrate the reproducibility of MFC data. This prototype MFC was able to produce a maximum of 100 mW/m3 of reactor volume, at optimized electrode distance (2.54 cm), ionic strength of 0.5, and using a culture electrochemically activated for three generations. The data was reproducible with maximum standard errors of ± 15 mW/m3. Using this basis, a new fuel cell design was introduced, in which the anode electrode surface was increased and reactor volume was decreased. To investigate the prediction of MFC performance under different operating conditions, the new MFC model was used in a 3-level, three factor (substrate concentration, ionic strength, and medium pH) Box-Behnken experimental design. A statistical model was constructed, which could reliably predict power outputs in the MFC with less than 10% error. The statistical model optimized operating conditions in the MFC (pH 9, NaCl concentration of 15 g/L, substrate concentration of 5 g/L), corresponding to a power density of 1027 mW/m3. The effect of dimensionless quantities on MFC performance was briefly investigated: higher Schmidt values resulted in lower power densities, indicating the negative impact of increased viscosity on mass transport; all Reynolds values resulted in washout, but increases in power densities were still observed during flow regime transitions; finally, power decreased with increase Peclet values, indicating that convective mass transport was removing substrate and bacteria faster than reactions could occur. The results of this study contribute to the scale-up of MFC technology based on the prediction of MFC performance, the ability to produce repeatable results, and the demonstration of MFC performance as a function of dimensionless, scale independent parameters. This work furthers scholarship in a crucial area of MFC research, necessary for the technology's widespread application. / Le manque d'accès à l'électricité et à l'eau potable parmi les pays en développement augmente l'importance de l'innovation en domaine de technologie verte et énergie renouvelable, afin d'introduire une technologie qui est applicable à grande échelle. En tant que tel, les piles à combustible microbien sont présentement recherchées. Une pile à combustible microbien (PCM) est un appareil dans lequel les bactéries sont utilisées à oxyder les molécules organiques, afin de libérer des électrons; ces électrons sont transférés hors de la cellule à l'anode jusqu'au cathode, produisant le courant. Les seuls sous-produits de ce processus sont de l'eau et du dioxyde de charbon. Quoique le domaine de recherche en PCM ait avancé, notamment en optimisation de la production d'électricité, les puissances de sortie ne sont pas toujours reproductibles de façon fiable, et il est présentement impossible de prédire la performance des PCM aux conditions opératoires différentes. La résolution de ces deux défis est considérée parmi les questions le plus importantes de la recherche en PCM. Pendant cette étude, une PCM à un seul compartiment, à l'emploi de l'E. coli K12 comme catalyseur biologique, a été construite au but d'optimiser la production d'électricité et les conditions opératoires, et pour démontrer des données reproductibles. Ce prototype était capable de produire une puissance maximale de 100 mW/m3 (volume du réacteur), aux conditions suivants : espace de 2.54 cm entre les électrodes, force ionique de 0.5, et culture électrochimique de troisième génération. Les données étaient reproductibles avec erreur minimale (± 15 mW/m3). Étant donné ces résultats, un prototype nouveau, de moins volume, était introduit, avec un anode de graphite en format pinceau. Une plan d'expérience Box-Behnken (trois facteurs de trois niveaux chaque) était conçu afin de prédire la performance de la PCM aux conditions opératoires différentes (concentration de substrat, concentration de NaCl, et pH). Un modèle statistique était construit, capable de prédire la puissance électrique de la PCM avec erreur minimale (moins de 10%). Selon le modèle, les conditions opératoires optimales (pH 9, concentration de NaCl 15 g/L, concentration de lactose 5 g/L) ont correspondu à une puissance de 1027 mW/m3. L'effet des quantités sans dimensions sur la performance de PCM était recherché brièvement : lorsque le valeur de Sc augmentait, la puissance décroisse, indiquant l'effet négatif de la viscosité élevée sur le transport de la masse en PCM; les valeurs de Re examinés ont tous résulté en dilution extrême de la culture en PCM, mais l'accroissement de puissance été observé pendant les transitions d'un régime d'écoulement à l'autre; finalement, la puissance électrique décroissaient lorsque le valeur de Pe augmentait, un effet qui indique que la transport de masse en PCM était trop fort. Les résultats de cette étude montent les efforts en commercialisation des PCM, ayant contribué les données sur la prédiction de la performance des PCM qui sont reproductibles, et la description de relations entre la performance des PCM et les quantités sans dimension. La recherche présentée ici avance un parti crucial du domaine de PCM.
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Hydraulic Fracturing and Water Use in Dallas, TexasYates, Sarah 06 November 2013 (has links)
Dallas, Texas is located in North Texas and sits above the eastern portion of the Barnett Shale natural gas formation. Hydraulic fracturing, or fracking, was introduced to the region as a means to access previously inaccessible natural gas within the formation. This fracking concerns many because it requires large amounts of fresh water, an average of over 4 million gallons per well within Dallas Water Utilities service area. This thesis examines whether water use for fracking will have a negative effect on the water supply for the city of Dallas and its wholesale water customer cities. The water is typically removed from the water cycle because chemical additives required for fracking are difficult to remove and the water is often disposed of underground. Methods of recycling and treating this water are being pursued but are not currently employed at a high rate in the Barnett Shale area. Water is of special concern in this region due to drought, increasing population, and the recent discovery of Zebra Mussels in the water supply. Texas is experiencing the worst drought other than the 1950s drought of record which is reducing the available water supply, through both evaporation and lack of recharge. The population in the area is also projected to nearly double by 2060 which will lead to increased water demand. Zebra Mussels have been found in Dallas supply system and these mussels are impossible to remove and can clog pipes, reducing the flow of water and so potentially reducing the available supply. Future water plans are prepared to address these issues, focusing on conservation as well as increasing available supplies. Based on this analysis, hydraulic fracturing in Dallas, Texas and within Dallas Water Utilities wholesale customers should not significantly affect Dallas water supply in the near term. Other methods of conservation, such as limiting landscape watering, should be considered as more beneficial ways to save water.
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Evaluating the Effects of Road Crossing Structures on Stream-Associated Amphibians in the Wilson River Watershed, Tillamook State Forest, OregonTwitchell, Sara Erin 18 May 2013 (has links)
<p> As replacement and removal of undersized culverts gains momentum as an effective technique for restoring natural stream flows and removing fish passage barriers, it is important to evaluate the benefits of these efforts on the in-stream and adjacent riparian habitat for other species of potential concern. This study compares stream-associated amphibian (SAA) occurrence in streams adjacent to different road crossing structures on unpaved forest roads in the Wilson River watershed located within the Tillamook State Forest, Oregon. Surveys were conducted at road crossing structures for three taxa of SAA; Pacific giant salamander (<i>Dicamptodon tenebrosus</i>), coastal tailed frog (<i>Ascaphus truei</i>), and Columbia torrent salamander (<i>Rhyacotriton kezeri</i>). Statistical models were created to analyze the effect of habitat variables on SAA occupancy, and determine whether those variables changed relative to road crossing structures. </p><p> Results showed that coastal tailed frog occupancy was positively associated with dissolved oxygen and crayfish presence, negatively associated with longitude, and had a slight quadratic relationship to channel confinement. Because all sites were highly saturated with oxygen, percent dissolved oxygen was likely a surrogate for one or more other covariates, such as in-stream habitat or substrate size. Detection rates of Pacific giant salamander were too high and detection rates of Columbia torrent salamander were too low to provide reliable models, but they did provide some insight into the factors affecting occupancy in the study area, including information about their interactions with road crossing structures. Occupancy rates of Pacific giant salamanders in the study area appear to be unaffected by road crossings, fish passable or otherwise. Conversely, torrent salamanders seemed to be mostly absent from the study sites altogether, but based on the one stream where they were detected, they are not excluded from occupying fish barrier culvert sites. </p><p> Top weighted habitat covariates, including dissolved oxygen, channel confinement, crayfish and fish presence, and flow constriction are all indicators of disturbance that can be linked to road crossings. Although the size and structure of road crossings did not prove to significantly influence SAA occupancy, indicators of stream disturbance that can be related to road crossings were included in the best models for predicting occupancy, demonstrating the importance of reducing disturbance related to road crossings on streams.</p>
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