Miniemulsion technology is attracting increasing interest for the preparation of nano-size particles. However, the barrier to industrialising miniemulsion-based products is the lack of an energy efficient and scalable homogenisation device. Current laboratory techniques consist of batch units, however trends are leaning towards developing continuous processes. The objective of the work presented here is to investigate the use of the rotor-stator (RS) and static mixers (SM) as homogenisation devices and ultimately develop a continuous emulsification/polymerisation process for the preparation of miniemulsions. Initially we investigated the RS as a homogenisation device and found that we were able to generate droplets ranging from 300 nm to 2 μm, at industrially pertinent solids content. Subsequently, we investigated the use of SM and compared their performance in terms of mean droplet size evolutions with the rotor-stator. We were able to generate droplets < 200 nm in size and polymerise them in a stable fashion. All the available emulsification devices were then compared in terms of power/energy consumption, droplet size distributions and shear rates. It was observed that with energy costs being of similar orders of magnitude, SM imposed less shear, produced relatively narrow distributions and were better adapted to scale-up, making them the optimal choice for miniemulsification. Energy savings were increased by reducing coalescence during the emulsification step by using in situ generated surfactants, ultimately reducing emulsification time. Neutralising a water-soluble base with an oil-soluble acid almost instantaneously generates in situ surfactants at the oil-water interface. The reduction in emulsification time was partially attributed to the elimination of the relatively slow adsorption step typical of preformed surfactants. These results were used to show that emulsifying in situ formulations at moderate flow rates in line with SMX mixers can substantially reduce emulsification time from 30 minutes, with preformed surfactants, to ~30 seconds. With such a rapid emulsification step, it was possible to test the feasibility of the continuous emulsification process followed by polymerisation in a tubular reactor. Comparing this process with a batch operation, similar results for the ratio of NP/ND and conversion were obtained, but the continuous process was accomplished in a single step. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2010-04-19 03:32:08.766

No description available.

The primary objective of this study was to investigate the use of water table management (WTM) as a microbial delivery system for in-situ bioaugmentation of contaminated soils. In addition, the use of Rhizobium ( R.) for PCB degradation in soils was evaluated. / First, the presence and isolation of a variety of strains of Rhizobium meliloti was demonstrated using plant nodulation tests on alfalfa plants in soils that were contaminated for over 15 years with PCBs, PAHs and heavy metals. Next, R. meliloti, strain A-025, was selected based on its membrane (hydrophobicity, adhesion) characteristics and its potential to transform PCBs. This strain was delivered and implanted in sod columns, 200 mm in diameter x 1000 mm in length, packed with a sandy loam soil, using surface and subirrigation. The results of this study showed that subirrigation led to a higher number and a more uniform distribution of the bacterial cells in the soil at 60, 300, 500, and 700 mm depths, than surface irrigation. / In a different setup, similar column were packed with a PCB contaminated soil. These soil columns were bioaugmented with three bacterial cultures, i.e., R. meliloti (strain A-025), Comomonas testosteroni (strain B-356) and an indigenous bacterial consortium using subirrigation. The results indicated that bioaugmentation of the PCB contaminated soil was possible by using subirrigation. Bioaugmentation with the indigenous culture was observed to be more effective in the biodegradation of PCBs than with A-025 and B-356 cultures at 140 and 340 mm depths. However, at 590 mm depth, bioaugmentation with strain A-025 was observed to be better than the other treatments. Sequential aerobic and anaerobic cycles appear to be of significance for effective dechlorination of PCB congeners to lower chlorinated congeners. / In a separate exploratory study, the rhizospheric effects of alfalfa plants on R. meliloti for PCB depletion were investigated. The results suggest that the growth of alfalfa plants and bioaugmentation of soil with R. meliloti, strain A-025, increased the depletion of PCB congeners in the soil as compared to bioaugmentation alone. In other preliminary studies, the results showed that the presence of PCBs in a sandy loam soil increases the filtration of bacterial cells. Also, soil type and the presence of PCBs affected water infiltration, moisture, and hardness of the soil. Furthermore, water table management system along with bioaugmentation of soil columns with R. meliloti, strain A-025, decreased the concentration of atrazine by 31% during anaerobic and aerobic cycles and reduced the concentration of nitrate by 87% and 78% in the absence and presence of atrazine, respectively, in the drainage water. / The overall results of this work indicate that water table management (subirrigation) can be used for bioaugmentation of contaminated soils. Also, use of R. meliloti may prove to be an interesting option for soils contaminated with PCBs, atrazine and nitrate.

No description available.

Les préoccupations de la population mondiale à l’égard des problèmes de pollution des cours d’eau et de l’environnement en général datent de longtemps et ne cessent de prendre de plus en plus d’ampleur dans le monde actuel. Bien que plusieurs recherches aient été menées en vue [de] cerner la problématique, Santé Canada et l’U.S. EPA (United States Environment Protection Agency) ont souligné le besoin de surveiller les polluants émergents, dans les effluents et les boues d'épuration des eaux usées, dans les lixiviats de sites d'enfouissement et dans les eaux réceptrices situées en aval des stations d’épuration des eaux usées (STEP). C'est dans cette optique que l’étude présente, qui vise à simuler le transport in situ de polluants émergents et de métaux traces dans un cours d’eau, en aval de l’exutoire d'une STEP municipale à l’aide du modèle hydrodynamique-environnemental Delft3D, a été élaborée. L'étude porte spécifiquement sur le plastifiant bisphénol A (BPA), 22 molécules pharmaceutiques et 6 métaux traces (Cu, Pb, Mn, Mo, V, Fe). Les données requises pour caler et valider le modèle hydrodynamique ont été mesurées in situ dans le bief étudié de la rivière Coaticook (Qc, Canada). Quant aux concentrations des substances visées requises pour la modélisation de qualité, elles ont été analysées à l’aide d’un Ultra Performance Liquid Chromatography couplé à un spectromètre de masse en tandem (UPLC/MS-MS) pour le cas du BPA et des pharmaceutiques et d’un Induced Coupled Plasma couplé à un spectromètre de masse (ICP/MS) pour le cas des métaux traces. Dans le cas du BPA et des molécules pharmaceutiques, les concentrations dans les échantillons de l’effluent de la STEP, de l’eau de surface et des sédiments étaient inférieures à leurs limites de quantification (évaluées respectivement à 3.5ppb et 10ppt). Seul l’ibuprofène a été retrouvé avec une concentration de 10ppt dans l’effluent de la STEP. Pour ce qui est des métaux traces, les concentrations respectives du Mn, V et Fe étaient de 12.9ppb, 0.15ppb et 1303ppb dans l’effluent de la STEP et de 3.3±0.6ppb, 0.06±0.04ppb, 381±65ppb dans l’eau de surface. Les concentrations du Pb et du Mo dans l’effluent et dans l’eau de surface se sont avérés inférieures à leurs LDQ. Dans les sédiments, seuls le Mn et le Fe ont été retrouvés avec des concentrations de 2261+ 967 mg/kg et de 15664+ 6040 mg/kg respectivement. Ainsi, seul le Fe et le Mn se sont avérés problématique pour la modélisation de qualité vu que les résultats d’analyse des autres substances étaient soit peu pertinents, soit en dessous des LDQ ou soit inférieurs aux critères de qualité des sédiments d'Environnement Canada et du MDDEFP. Les résultats de la modélisation ont montré qu’il existe une bonne concordance entre les résultats de modélisation de qualité et ceux observés in situ. Les erreurs relatives moyennes dans le bief étudié ont été évaluées à 27.3% (r² = 0.7) pour les hauteurs d’eau et 32.5% (r² = 0.66) pour les vitesses moyennes lors de la modélisation hydrodynamique et à 7.4 % (R² = 0.95) et de 16.10 % (R² = 0.88) respectivement sur les concentrations de Mn dans l’eau de surface et dans les sédiments lors de la modélisation de la qualité de l’eau.

Treatment success often depends on the availability of accurate and reliable diagnostic assays to guide clinical practitioners in their treatment choices. An optimal test must excel in specificity and sensitivity, and depending on the application area time, low-cost and simplicity are equally important. For instance, time is essential in infectious diagnostics but this is less important in non-invasive prenatal testing (NIPT). In NIPT, specificity and sensitivity are the most important parameters. In this thesis I describe the development of four different methods, all based on padlock probes and rolling circle amplification, intended for molecular diagnostics. Application areas range from infectious disease diagnostics to NIPT and oncology. The methods described have in common that they overcome certain limitations of currently available assays. This thesis includes two new assays targeting infectious agents: one assay specifically detecting a highly variable double stranded RNA virus and the second assay demonstrating a new format of antibiotic susceptibility testing, which is rapid and generally applicable to different pathogens. Furthermore, I describe the development of a method that uses methylation markers to enrich fetal DNA, accurately quantify chromosome ratios and thus, detecting trisomy 21 and 18. The fourth method described in this thesis uses gap-fill ligation of padlock probes to detect diagnostic relevant point mutations with high specificity in situ. The assays presented have the potential, after automation and successful validation and verification studies, to be implemented into clinical practice. Furthermore, these assays demonstrate the wide applicability of padlock probes which, due to their properties in regard to specificity and multiplexity, are useful tools for nucleic acid detection in vitro as well as in situ. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.</p>

Guppies exhibit color based sexual dimorphism and females generally prefer the most colorful males. It has also recently been found that guppies possess a large opsin repertoire. As opsins are the receptors responsible for color vision, this ten gene repertoire might have contributed to the evolution of extravagant male coloration in this species. My study starts by characterizing the opsin repertoire of Jenynsia onca, a noncolorful relative of the guppy belonging to the family Anablepidae (sister group to Poeciliidae, of which the guppy is a member). A PCR based survey indicated that J. onca had a very similar opsin repertoire to the guppy; J. onca had nine genes including orthologs of all but one of the guppy opsins. To gain further insight into the origin of the guppy repertoire, a bioinformatics based survey of ray-finned fish opsins was undertaken. This revealed that large opsin repertoires are common in ray-finned fish and are the product of gene duplication events, spanning the age of the taxon Teleostei. Given that the large opsin repertoire of the guppy did not appear to be perfectly correlated with the evolution of color based sexual selection in this lineage, I turned to investigating the expression of this opsin repertoire. In situ hybridization was used to characterize the pattern of opsin expression across the surface of the retina of adult male and female guppies. In situ hybridization demonstrated that most opsin genes had distinct expression profiles. These expression patterns also indicated that sensitivity and discrimination in the dorsal retina might differ from the ventral retina; the ventral retina appears to be tuned to middle-wavelength light (green), while the dorsal retina is predicted to have exceptional wavelength discriminatory ability and broad spectral sensitivity. This expression data was then used to evaluate models of sexual selection in the context of the predicted visual capacity of the guppy. / Graduate

The growing interest in increasing the wear resistance and hardness of surfaces that are in contact with abrasives or corrosive materials has inspired the development of several processes for creating protective coatings. In-situ laser cladding is one of the most promising of these processes. It enables the formation of a uniform coating by melting powder to form the desired composition from a pure powder component. In this research, pure Ti, graphite, and Fe are used for in-situ laser cladding on a steel substrate to form an Fe-TiC metal matrix composite (MMC). The effect of laser parameters on both the quality of the bonding and morphology of the in-situ-formed TiC iron-based composite clad are investigated. Results show that laser parameters play a crucial role in determining the clad quality and clad microstructure. Two combined parameters, effective energy and powder deposition density, are used to study the effect of laser parameters (i.e., laser power, scan speed and powder feed rate) on the clad properties. While results indicate that combined parameters help to determine the quality limit, laser process parameters need to be taken into account in order to study the clad microstructure. To increase the clad hardness and TiC volume fraction, C:Ti atomic ratio should increase from 45:55 to 55:45, and Fe percentages in the powder composition should decrease from 70 wt% to the 10 wt%. By varying the powder composition, a change in TiC morphology, clad microstructure and clad hardness occurs. The dilution effect is also considered in the interpretation of results. In order to estimate wear resistance, the ASTM G65-A procedure was selected to perform tests on various clad compositions. An increased wear resistance is seen when the volume fraction of TiC is increased.

The presence of coal tars in the subsurface associated with former manufactured gas plants (MGPs) offers a remediation challenge due to their complex chemical composition, dissolution behaviour and recalcitrant characteristics. A former MGP site in Clearwater Beach, Florida was characterized and bench-scale analyses were conducted to assess the potential for in situ chemical oxidation (ISCO) using persulfate to treat MGP residuals. Completion of a conceptual site model identified a homogeneous, silty sand aquifer, with an average hydraulic conductivity of approximately 2.3x10-3 cm/s and a groundwater flow rate of 2 cm/day in the direction of S20°E. Six source zones, three near the water table and three in the deep aquifer were estimated to have a total volume of 108 m3. A multi-level well transect was installed to monitor concentrations of dissolved compounds and to estimate mass discharge downgradient of the source zones over time. On average, the morphology of the aqueous concentrations remained consistent with time. A total mass discharge across the transect of 94 mg/day was estimated for site-specific compounds. Bench-scale tests were conducted on aquifer sediments and groundwater samples. The aquifer was determined to have a low buffering capacity, low chemical oxygen demand, and low natural oxidant interaction (NOI) with persulfate. Aqueous batch experiments identified the potential for iron (II) activated persulfate to reduce concentrations of BTEX and PAHs below method detection limits (MDLs). Unactivated persulfate was able to reduce BTEX concentrations to below MDLs after 14 days; however, the concentration of PAH compounds remained above MDLs after 14 days. Higher iron doses within the system were shown to be more effective in reducing BTEX and PAH compounds. Column experiments designed to mimic site conditions were used to evaluate the feasibility of persulfate treatment on impacted sediments from the Clearwater site. Two sets of column experiments were conducted: one using unactivated persulfate followed by alkaline activated persulfate; and one using iron (II) activated persulfate. On average, unactivated persulfate was able to reduce BTEX and PAH aqueous effluent concentrations by > 75% and 40%, respectively, after a total dose of 60 g/g soil. Two additional doses of alkaline activated persulfate (total persulfate dose of ~80g/g soil) in these columns were able to further reduce effluent BTEX and PAH concentrations by > 90% and > 75%, respectively. Iron (II) activated persulfate reduced effluent BTEX concentrations by > 70% and PAHs by > 65% after a total dose of 35 g/g soil. Average reductions in mass for BTEX and PAH compounds were approximately of 48% and 26% respectively in the iron (II) activated persulfate columns, and 24% and 10%, respectively in the alkaline activated persulfate columns. The potential for the ability to use in situ chemical oxidation using persulfate for the remediation of MGP residuals in the subsurface is evaluated using field measurements and bench-scale experimentation. The reductions observed in aqueous phase compounds in MGP groundwater as observed in the laboratory indicate the potential for reductions in groundwater concentrations at this and other contaminated former MGP sites. However, column experiments, indicating the inability for activated persulfate to reduce all identified compounds in the MGP NAPL suggest source treatment with activated persulfate would not reduce concentrations to below Florida Department of Environmental Protection natural attenuation concentrations.

Fenugreek (Trigonella foenum-graecum L.) is a single-cut, annual legume typically grown for seed. Fenugreek has potential as a forage because it maintains high quality throughout the growing season, and offers the benefits of a legume in a crop rotation. This work aimed to evaluate the growth of two fenugreek genotypes, AAFC F70 and CDC Quatro, in the central AB area over two growing seasons, and to evaluate fenugreek haylage degradation and digestion in dairy cows. In general, the two genotypes were similar in their growth patterns and fenugreek biomass yield was comparable to alfalfa in the same area. Plant quality was sufficient to be used for lactating dairy cows. The digestion studies revealed that while Quatro haylage was comparable to alfalfa haylage, F70 haylage was of lower quality and was not utilized to the same extent by dairy cows as the other two forage types. / Plant Science