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21	Caractérisation des interfaces acier-fonte-carbone de l'ensemble anodique d'une cuve d'aluminium Martin, Marie-Hélène 20 April 2018 (has links) L’industrie de l’aluminium vit des bouleversements économiques, d’où l’importance de réduire les coûts d’opération. Le présent projet se penche sur les pertes ohmiques du scellement anodique. Les essais ont été complétés entre les conditions ambiantes jusqu’à charge et température maximales permises par le banc d’essais. Les travaux furent complétés sur un banc d’essais novateur - permettant une stabilisation rapide de la température et une faible oxydation de la portion carbonée de l’échantillon - et des échantillons (acier-fonte-carbone) fabriqués pour reproduire la réalité. Ensuite, une régression non linéaire a été utilisée pour modéliser le comportement mesuré en laboratoire. L’analyse statistique démontre que le modèle représente adéquatement le comportement des interfaces à mesure que la charge appliquée et la température s’intensifient. La comparaison avec la littérature démontre une similitude, toutefois les résultats diffèrent de façon significative. Ceci s’explique par l’utilisation de matériaux différents et par le changement de méthode expérimentale. / The aluminum industry faces economical headwinds, thus needing to reduce its operating costs. The project studies specifically energy losses at anode sealing location. Experiments were conducted from room conditions up to the maximum capacity of the bench test. Laboratory work was completed using tri-material samples (made in such a way to replicate accurately reality) and an innovative bench test using magnetic induction as a source of heat that enables minimal heat-up time and sample oxidation during experiments. Non-linear regression was then used to retrieve a model from laboratory results. Analysis showed that a power model represents accurately the interfaces behavior from room to operation conditions. Comparison with literature showed that the order of magnitude is the same but results are not similar. This observation can be explained by the use of slightly different materials and also due to the use of a different experimental procedure. TA 7.5 UL 2014 Acier -- Propriétés électriques Fonte -- Propriétés électriques Carbone -- Propriétés électriques Anodes -- Propriétés électriques
22	The Effect of Aluminium Industry Effluents on Sediment Bacterial Communities Gill, Hardeep 19 October 2012 (has links) The goal of this project was to develop novel bacterial biomarkers for use in an industrial context. These biomarkers would be used to determine aluminium industry activity impact on a local ecosystem. Sediment bacterial communities of the Saguenay River are subjected to industrial effluent produced by industry in Jonquière, QC. In-situ responses of these communities to effluent exposure were measured and evaluated as potential biomarker candidates for exposure to past and present effluent discharge. Bacterial community structure and composition between control and affected sites were investigated. Differences observed between the communities were used as indicators of a response to industrial activity through exposure to effluent by-products. Diversity indices were not significantly different between sites with increased effluent exposure. However, differences were observed with the inclusion of algae and cyanobacteria. UniFrac analyses indicated that a control (NNB) and an affected site (Site 2) were more similar to one another with regard to community structure than either was to a medially affected site (Site 5) (Figure 2.4). We did not observe a signature of the microbial community structure that could be predicted with effluent exposure. Microbial community function in relation to bacterial mercury resistance (HgR) was also evaluated as a specific response to the mercury component present in sediments. Novel PCR primers and amplification conditions were developed to amplify merP, merT and merA genes belonging to the mer-operon which confers HgR (Table 5.6). To our knowledge, the roles of merP and merT have not been explored as possible tools to confirm the presence of the operon. HgR gene abundance in sediment microbial communities was significantly correlated (p < 0.05) to total mercury levels (Figure 3.4) but gene expression was not measurable. We could not solely attribute the release of Hg0 from sediments in bioreactor experiments to a biogenic origin. However, there was a 1000 fold difference in measured Hg0 release between control and affected sites suggesting that processes of natural remediation may be taking place at contaminated sites (Figure 3.7). Abundance measurements of HgR related genes represent a strong response target to the mercury immobilized in sediments. Biomarkers built on this response can be used by industry to measure long term effects of industrially derived mercury on local ecosystems. The abundance of mer-operon genes in affected sites indicates the presence of a thriving bacterial community harbouring HgR potential. These communities have the capacity to naturally remediate the sites they occupy. This remediation could be further investigated. Additional studies will be required to develop biomarkers that are more responsive to contemporary industrial activity such as those based on the integrative oxidative stress response. bacteria heavy metal resistance mercury mer operon sediment biomarker community diversity mercuric reductase sediment metagenome environmental microbiology industry bauxite alumina red mud Saguenay River, QC PCR qPCR bioreactor gene merT merP merA rpoB katG glnA river system environmental DNA aluminum industry Bayer Process Hall–Héroult Process 16S rRNA UniFrac sediment wash buffer community richness mothur ribosomal database project DNA sequencing aluminum aluminium RNA metatranscriptome ecotoxicology environmental contaminants industrial effluent
23	The Effect of Aluminium Industry Effluents on Sediment Bacterial Communities Gill, Hardeep 19 October 2012 (has links) The goal of this project was to develop novel bacterial biomarkers for use in an industrial context. These biomarkers would be used to determine aluminium industry activity impact on a local ecosystem. Sediment bacterial communities of the Saguenay River are subjected to industrial effluent produced by industry in Jonquière, QC. In-situ responses of these communities to effluent exposure were measured and evaluated as potential biomarker candidates for exposure to past and present effluent discharge. Bacterial community structure and composition between control and affected sites were investigated. Differences observed between the communities were used as indicators of a response to industrial activity through exposure to effluent by-products. Diversity indices were not significantly different between sites with increased effluent exposure. However, differences were observed with the inclusion of algae and cyanobacteria. UniFrac analyses indicated that a control (NNB) and an affected site (Site 2) were more similar to one another with regard to community structure than either was to a medially affected site (Site 5) (Figure 2.4). We did not observe a signature of the microbial community structure that could be predicted with effluent exposure. Microbial community function in relation to bacterial mercury resistance (HgR) was also evaluated as a specific response to the mercury component present in sediments. Novel PCR primers and amplification conditions were developed to amplify merP, merT and merA genes belonging to the mer-operon which confers HgR (Table 5.6). To our knowledge, the roles of merP and merT have not been explored as possible tools to confirm the presence of the operon. HgR gene abundance in sediment microbial communities was significantly correlated (p < 0.05) to total mercury levels (Figure 3.4) but gene expression was not measurable. We could not solely attribute the release of Hg0 from sediments in bioreactor experiments to a biogenic origin. However, there was a 1000 fold difference in measured Hg0 release between control and affected sites suggesting that processes of natural remediation may be taking place at contaminated sites (Figure 3.7). Abundance measurements of HgR related genes represent a strong response target to the mercury immobilized in sediments. Biomarkers built on this response can be used by industry to measure long term effects of industrially derived mercury on local ecosystems. The abundance of mer-operon genes in affected sites indicates the presence of a thriving bacterial community harbouring HgR potential. These communities have the capacity to naturally remediate the sites they occupy. This remediation could be further investigated. Additional studies will be required to develop biomarkers that are more responsive to contemporary industrial activity such as those based on the integrative oxidative stress response. bacteria heavy metal resistance mercury mer operon sediment biomarker community diversity mercuric reductase sediment metagenome environmental microbiology industry bauxite alumina red mud Saguenay River, QC PCR qPCR bioreactor gene merT merP merA rpoB katG glnA river system environmental DNA aluminum industry Bayer Process Hall–Héroult Process 16S rRNA UniFrac sediment wash buffer community richness mothur ribosomal database project DNA sequencing aluminum aluminium RNA metatranscriptome ecotoxicology environmental contaminants industrial effluent
24	The Effect of Aluminium Industry Effluents on Sediment Bacterial Communities Gill, Hardeep January 2012 (has links) The goal of this project was to develop novel bacterial biomarkers for use in an industrial context. These biomarkers would be used to determine aluminium industry activity impact on a local ecosystem. Sediment bacterial communities of the Saguenay River are subjected to industrial effluent produced by industry in Jonquière, QC. In-situ responses of these communities to effluent exposure were measured and evaluated as potential biomarker candidates for exposure to past and present effluent discharge. Bacterial community structure and composition between control and affected sites were investigated. Differences observed between the communities were used as indicators of a response to industrial activity through exposure to effluent by-products. Diversity indices were not significantly different between sites with increased effluent exposure. However, differences were observed with the inclusion of algae and cyanobacteria. UniFrac analyses indicated that a control (NNB) and an affected site (Site 2) were more similar to one another with regard to community structure than either was to a medially affected site (Site 5) (Figure 2.4). We did not observe a signature of the microbial community structure that could be predicted with effluent exposure. Microbial community function in relation to bacterial mercury resistance (HgR) was also evaluated as a specific response to the mercury component present in sediments. Novel PCR primers and amplification conditions were developed to amplify merP, merT and merA genes belonging to the mer-operon which confers HgR (Table 5.6). To our knowledge, the roles of merP and merT have not been explored as possible tools to confirm the presence of the operon. HgR gene abundance in sediment microbial communities was significantly correlated (p < 0.05) to total mercury levels (Figure 3.4) but gene expression was not measurable. We could not solely attribute the release of Hg0 from sediments in bioreactor experiments to a biogenic origin. However, there was a 1000 fold difference in measured Hg0 release between control and affected sites suggesting that processes of natural remediation may be taking place at contaminated sites (Figure 3.7). Abundance measurements of HgR related genes represent a strong response target to the mercury immobilized in sediments. Biomarkers built on this response can be used by industry to measure long term effects of industrially derived mercury on local ecosystems. The abundance of mer-operon genes in affected sites indicates the presence of a thriving bacterial community harbouring HgR potential. These communities have the capacity to naturally remediate the sites they occupy. This remediation could be further investigated. Additional studies will be required to develop biomarkers that are more responsive to contemporary industrial activity such as those based on the integrative oxidative stress response. bacteria heavy metal resistance mercury mer operon sediment biomarker community diversity mercuric reductase sediment metagenome environmental microbiology industry bauxite alumina red mud Saguenay River, QC PCR qPCR bioreactor gene merT merP merA rpoB katG glnA river system environmental DNA aluminum industry Bayer Process Hall–Héroult Process 16S rRNA UniFrac sediment wash buffer community richness mothur ribosomal database project DNA sequencing aluminum aluminium RNA metatranscriptome ecotoxicology environmental contaminants industrial effluent

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