The effects of a DC voltage on the catalytic combustion rate of natural gas in air over a platinum wire in various configurations is examined. In most cases a high applied voltage reduces and quenches the catalytic reaction. These effects are dependent on the catalyst surface charge density but not on the direction of the field. Greater effects were also observed when the field was applied on the upstream rather than the downstream side of the catalyst. Although the mechanism of this quenching effect is unknown, it is suggested that it involves the generation and diffusion of charged gas-phase species and their interaction with the catalyst surface. Possible quantum effects are also discussed. Further work to verify or refute the mechanisms presented here is suggested. / Master of Science

<p>Pollution problems have drawn worldwide awareness and become significantly important now. Particulate matter (PM) emission is one of the key pollution issues. Particulate matter has a significant impact on the environment and human health, especially particle sizes that range below 10μm. Researches continuously work an improvement of fine particulate matter collections emitted from all kinds of sources, such as automobiles, industrial combustion, etc. Governments in many countries are planning to regulate the PM emission from the existing PM_10 (particle diameter<10μm) to new limits PM_2.5 (particle diameter<2.5μm) within the next few years. For this reason, present PM control system needs to be improved.</p><p>The objective of this work is to develop a dust flow separator type electrostatic precipitator (DFS-ESP) for the effective control of fine particulate matter emission from natural gas combustions. The characteristic of PM emitted from natural gas combustion is studied, and the performance of a DFS-ESP is evaluated by experiments and numerical predictions.</p><p>An experiment was conducted for natural gas combustion exhaust flow rates from 2.5 to 9 Nm^3/h, ESP applied voltages from 0 to 30kV, and gas temperature from 80 to 160°C. A series of particle measurements were conducted at upstream, downstream and middle of the DFS-ESP system by an optical particle counter for particle mass density, and by condensation nucleate particle counter for particle size distributions and particle number density. Particle sampled from the natural gas combustion system was also analyzed by an environmental scanning electron microscope (ESEM) technique. Flow velocity profile and pressure drop of the DFS-ESP were measured by a Pitot tube and diaphragm type pressure transducer, respectively.</p><p>The experimental results show that the particle size emitted from natural gas combustion ranges from 17 to 300nm in diameter, and the volume density is approximately from 5 x 10^8 #pt/m^3 to 5 x 10^9 #pt/m^3 depending on the combustion conditions. The dust flow separator can concentrate 90% of fine particles in 1 to 3% of the gas flow and divert it from the main flow to the ESP section where the particles can be removed. In terms of overall particle collection efficiency, the DFS-ESP system can remove up to 90% of the particles based on the number density. The pressure drop across the DFS-ESP is observed to be lower than lPa for the present range of flow rate, which is within acceptable limits for industrial applications.</p> / Thesis / Master of Applied Science (MASc)

Магистерская диссертация посвящена разработке информационно-моделирующей системы зажигательного горна агломерационной машины. Результатом работы является проектирование и программная реализация информационно-моделирующей системы зажигательного горна агломерационной машины. В ходе работы произведен анализ и формализация существующей методики расчета конструкции зажигательного горна, на основе которого был реализован проект создания информационно-моделирующей системы. Созданная в результате работы система позволяет проводить расчеты агломерационной шихты, горения твердого топлива, горения природного газа, периодов зажигания, а также выбор горелочных устройств и обоснования высоты горна. Предусмотрен вывод основных расчетных показателей в табличном виде с возможностью настройки отдельных показателей и предварительного просмотра отчета. Использование разработанной информационной системы позволяет существенно сократить временные затраты, повысить эффективность процессов проектирования новых и анализа эффективности существующих конструкций зажигательного горна агломерационных машин. / The master's thesis is devoted to the development of an information-modeling system of an incendiary hearth of an agglomeration machine. The result of the work is the design and software implementation of the information-modeling system of the incendiary furnace of the sinter machine. In the course of the work, an analysis and formalization of the existing methodology for calculating the design of the incendiary hearth was made, on the basis of which the project of creating an information-modeling system was implemented. The system created as a result of the work makes it possible to carry out calculations of the sinter charge, solid fuel combustion, natural gas combustion, ignition periods, as well as the choice of burner devices and justification of the height of the hearth. The output of the main calculated indicators is provided in a table form with the ability to configure individual indicators and preview the report. Using the developed information system can significantly reduce time costs, increase the efficiency of new design processes and analyze the effectiveness of existing incendiary furnaces of sinter machines.

Contexte : L’exposition professionnelle aux sous-produits de combustion est répandue et peut contribuer à l'étiologie du cancer du sein. Cette étude vise à estimer l’association entre l’exposition professionnelle à certains sous-produits de combustion et le risque postménopausique de cancer du sein. Méthodes : Cette étude cas-témoins populationnelle comprenait des femmes ménopausées âgées de 47-75 ans résidant à Montréal, Québec (2008-2011). Les cas incluaient 695 femmes ayant reçu un diagnostic cancer du sein malin et 608 témoins sélectionnés aléatoirement à partir de la Liste électorale du Québec, appariés aux cas en fréquence (groupes d'âge de 5 ans). L’information sur les facteurs de risque et l'historique professionnel a été recueillie par entrevue. Des hygiénistes industriels ont évalué l'exposition à 293 agents, dont six sous-produits de combustion. Le risque de cancer du sein associé à l'exposition professionnelle à certains sous-produits a été estimé, pour l'ensemble des tumeurs et leurs sous-types moléculaires, par régression logistique inconditionnelle avec rapports de cotes ajustés (RC) et intervalles de confiance à 95 % (IC 95%). Résultats : Des associations positives suggestives ont été trouvées entre l'exposition aux hydrocarbures aromatiques polycycliques et certains sous-types moléculaires de tumeurs : toutes tumeurs, RC=1,18 (IC95%=0,80-1,76), tumeurs luminales A, RC=1,25 (IC95%=0,81-1,93) et tumeurs luminales B, RC=2,09 (IC95%=0,87-4,60). Un risque élevé a été observé avec l'exposition aux fumées de cuisson pour les tumeurs HER2-enrichies (RC=2,63, IC95%=0,98-6,40). Conclusion : L'exposition à certains sous-produits de combustion peut augmenter le risque de certains sous-types moléculaires de cancer du sein. Des études futures explorant cette association sont justifiées. / Background: Postmenopausal breast cancer is the most common cancer among women, yet little is known about its association with occupational exposures. Exposure to combustion by-products is widespread in occupational settings and may contribute to breast cancer etiology. Here, we sought to estimate the association between lifetime occupational exposure to select combustion by-products and the risk of postmenopausal breast cancer. Methods: This population-based case-control study included postmenopausal women residing in Montreal, Quebec (2008-2011). Cases comprised 695 women aged 47-75 years diagnosed with incident malignant breast cancer, and 608 controls randomly selected from the Quebec Electoral List, frequency-matched to cases (5-year age groups). Information on risk factors and employment history was collected by interview. Exposure to 293 agents, including six combustion by-products was assessed by industrial hygienists. Unconditional logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for breast cancer risk, both overall and by tumor molecular subtypes, to occupational exposure to select combustion by-products. Results: We found suggestive positive associations between exposure to polycyclic aromatic hydrocarbons and certain molecular subtypes of tumors: for all tumors, OR=1.18 (95% CI: 0.80-1.76), Luminal A tumors, OR=1.25 (95% CI: 0.81-1.93) and Luminal B tumors, OR=2.09 (95% CI: 0.87-4.60). Elevated risked were observed for exposure to cooking fumes for HER2-enriched tumors (OR=2.63, 95% CI: 0.98-6.40). Conclusion: Exposure to select combustion by-products may increase the risk of certain hormonal subtypes of breast cancer. Future studies exploring this association are warranted.