No description available.

Thèses (M.A.)--Université de Sherbrooke (Canada), 2002. / Titre de l'écran-titre (visionné le 24 août 2006). Publié aussi en version papier.

Thèses (M.A.)--Université de Sherbrooke (Canada), 2001. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thèses (M.Serv.Soc.)--Université de Sherbrooke (Canada), 2006. / In ProQuest dissertations and theses. Titre de l'écran-titre (visionné le 18 oct. 2007). Publié aussi en version papier.

Thèse (M.A.)--Université Laval, 2003. / Bibliogr.: f. [105]-111. Publié aussi en version électronique.

No description available.

I detta examensarbete undersöks utdragsbärförmågan för en träskruv i KL-trä och i limträ. Detta görs genom praktiska försök med hjälp av en provmaskin. Dragproven syftar till att ta reda på hur mycket dragkraft som träskruven kan stå emot innan brott uppstår i förbandet, vilket innebär att skruven tappar greppet om träet och därmed dras ut. Resultaten från dragprovet ska sedan jämföras med den teori som finns i Eurokod och KL-trähandboken. Dragprovet ska tydliggöra hur stora dragkrafter en skruv i KL-träskivans olika skikt klarar av samt hur stora dragkrafter en skruv vinkelrätt fibrerna i limträet klarar av. Träskruven placerades på fyra olika sätt i kanten av KL-träskivan, det vill säga parallellt med fiberriktningen, vinkelrätt mot fiberriktningen, mellan skikten i KL-träskivan samt mellan brädorna parallellt med fiberriktningen. Detta gav en varierad utdragsbärförmåga mellan de olika testerna. I limträet undersöktes endast utdragsbärförmågan vinkelrätt mot fiberriktningen. Totalt genomfördes 47 dragprov. Resultaten från dragproven bevisar att det skiljer sig mycket i utdragsbärförmåga beroende på var i KL-träskivans kant som skruven placeras. I KL-trähandboken finns endast en ekvation som beskriver utdragsbärförmågan i kanten på skivan. Enligt teori blir alltså utdragsbärförmågan lika stor överallt i kanten av KL-träskivan, vilket inte stämmer överens med de framtagna testresultaten. För få dragprov utfördes i limträet för att kunna ge ett tydligt resultat. / Withdrawal capacityof wooden screws in CLT and glulam will be examined in this thesis. This is done by a practical attempt using a testing machine.The purpose ofthis tensile test is to find out how much force the wooden screw can handle before the breaking limit is reached. The results of the tensile tests will be compared with the theory contained in Eurocode and in the Swedish manual of CLT.The tensile test will clarify the amount of traction force that a wooden screw can withstand when placed in CLT and glulam. The wooden screws weretested in four different places along the edge of the CLT. The screws were placed parallel to the grain, perpendicular to the grain, between the layers in the CLT and also between the boards parallel to the grain. This resulted in a varied withdrawal capacity between the tests.There was only a single type of test performed on glulam where the screws were placed perpendicular to the grain.The results from the tensile tests shows that the location of the screws at the edge of the CLT matter and the withdrawal capacity depends on the placement of the screw. It only exists one equation for the withdrawal capacity at the edge of the CLT according to the Swedish manual of CLT.The withdrawal capacityis the same throughout the whole edge of the CLT according to theory, which does not match the test-results from the tensile tests.No clear results wereobtained in the glulam, because too few testswere made.

An increase in anthropogenic activity has led to the heightened levels of pollution entering aquatic systems. These excessive concentrations of heavy metals, nitrogen (N), and phosphorus (P) in water bodies can lead to several adverse impacts, such as eutrophication and human health risks. Therefore, the removal of pollutants from wastewaters, prior to their discharge into the natural environment, is of paramount importance. However, conventional wastewater treatment (WWT) technologies have their limitations; for instance, large capital/operational costs, and incomplete removal of contaminants. Therefore, innovative and more effective treatment technologies are required. Macro-algae typically have high growth and solar energy conversion rates, and are able to sequester nutrients, utilise CO2, and adsorb metals from aquatic environments. Therefore, algae may have potential applications in WWT. Furthermore, costs could be negated by the production of renewable algal biomass which may have a variety of commercially exploitable applications. However, issues such as poor selection of species or cultivation systems, and a lack of understanding of the influence of biological, chemical and physical factors, particularly in a highly dynamic wastewater environments, has led to varied results and prevented algal WWT becoming a widespread reality. In this thesis the algae Cladophora coelothrix and Cladophora parriaudii were studied as potential organisms for implementation into WWT. In addition to the features mentioned above, Cladophora was selected due to its ubiquity, filamentous morphology, which minimises harvesting costs, as well as their natural dominance and bloom forming behaviour in nutrient-rich environments. The influence of dewatering techniques, environmental factors, and nutrient regime upon the growth, nutrient/metal removal, and biochemical composition of the biomass were assessed. The first aspect of the thesis was an abiotic screening process, in order to investigate the robustness of Cladophora and its suitability for WWT applications on a fundamental level. Good rates of growth (4-13.3% d-1) and nutrient removal (45.2-99.9%) were observed throughout the screening process, except under the most extreme of conditions, e.g. pH 3. This indicated that Cladophora are potentially suitable for treating a broad range of wastewaters and merit further research to improve its potential applicability for WWT applications and commercial realisation. For instance, developing a reliable and accurate method for fresh weight (FW) assessment and hence productivity estimation. The determination of growth rate via FW measurement is one of the most basic aspects of algal biology, yet no standardised method exists for filamentous macro-algae. A variety of FW methods were systematically assessed in terms of accuracy and physiological impact. Methods involving mechanical pressing to dewater the biomass resulted in >25% reduction in the final biomass yield, compared to control cultures. The best method for FW determination employed a reticulated spinner, which was rapid, reliable, and easily standardised. Furthermore, this approach ensured accurate growth estimation with minimal physiological impact, measured as growth, maintenance of structural integrity and nutrient removal. This indicates that the method developed has the potential for widespread application in macro-algal cultivation, as such the method was employed throughout this thesis. The influence of nutrient regime on growth, biochemical composition, and bioremediation capacity was studied for both species of Cladophora. The nutrient regimes tested, representative of a broad variety of wastewaters, included four different N/P ratios, four N sources (ammonium, nitrate, nitrite and urea), and six different equimolar N source combinations provided at two N/P ratios. There were clear differences in performance between the two species, with higher rates of growth observed in all instances by C. parriaudii (4.75-11.2% d-1 vs. 3.98-7.37% d-1). Furthermore, ammonium was removed preferentially, whereas urea was removed secondarily. However, the presence of urea in the medium enhanced growth and uptake of the other co-existing N-forms, and yielded a carbohydrate-rich biomass (37.6-54% DW). These findings demonstrate that algal strain selection is important for treating wastewaters with specific nutrient profiles. In addition, results from this study suggest that nutrient regimes can be tailored to produce biomass with certain properties or characteristics, which make it suitable for further, potentially commercially viable, applications, such as metal biosorption. Since the biochemical characteristics of algal biomass were shown to be affected by nutrient regime, the final chapter describes research investigating the influence of nutritional history on metal biosorption. C. parriaudii was cultivated under different nutrient regimes to produce biomass of varying biochemical composition. This biomass was then used for metal removal, with maximum removal rates ranging from 1.08-2.35 mmol g1, 0.3-0.62 mmol g-1, 0.22-0.48 mmol g-1, and 0.43-0.61 mmol g-1 for Al2+, Cu2+, Mn2+, and Pb2+, respectively. Observations from this work indicate that metal removal is achieved by various mechanisms including adsorption, ion exchange, complexation and micro-precipitation, and that the biosorption efficacy is dependent upon the number and type of functional groups present, which are in turn influenced by the cultures nutrient regime. Overall, this study demonstrates the inter-relatedness of biological, chemical, and physical factors on algal growth, nutrient removal, biochemical composition, and metal biosorption. Results from this work have highlighted the need for standardisation in protocols, increased understanding of the influence of algal selection and nutrient characteristics in bioremediation, and highlighted the importance of considering biological aspects, specifically nutritional history, in biosorption studies.

One of the challenging design areas of high buildings is the determination of its stability and response to dynamic forces. These factors affect the horizontal deformations and fluctuations that the building will result in. This report examines the demands placed on the stability and deformations of high buildings through a literature study as well as examines these requirements with a reference building built into FEM-Design. The literature study shows that quite a few standards have to be taken into account and used in the design of tall buildings. Regarding limit values, only SS-ISO 10137 specifies maximum values for a building's peak acceleration relative to its own frequency. Limit values for transient deformations are not available. Furthermore, the literature study shows that plenty of studies of human perception and tolerance to movements in buildings have been performed. The movements have been shown to cause physical andmental discomfort if exaggerated, which SS-ISO 10137 bases its limits after. The 75-meter reference building, modeled in FEM-Design, was built to calculate the building's own frequency, transient deflection, and self-weight. The wind loads have been calculated separately and entered into the program. Calculations for the building's peakacceleration have then been calculated and compared to the limitvalues in SS-ISO 10137. The structure of the reference building, consisting of 25-storeys in concrete, met the standard requirements for housing and should be able to be built without the risk of discomfort among the residents. Other inputs were 250 and 200 mm floor and wallthickness in C25 / 30 and VKR pillar in each corner, 200x200x10 mmin quality S355. The plan levels are square 21.8m wide andidentical to all 25 levels.The model-building met the requirements for living space accordingto SS-ISO 10137 with respect to peak acceleration and frequency. However, the calculated horizontal deformations did not have anylimit values to be compared to and were therefore not compared to any restrictions.

Magister Philosophiae - MPhil / Due to an increasing demand for energy, alternative renewable energy sources are investigated globally. However fossil fuels are still one of the main energy sources. The combustion of these fuels produces by-products such as SOx, NOx and CO2, which have detrimental effects on the environment and human health. Therefore, effective methods are needed to minimize the pollution and affects that these by-products cause. Catalysts are commonly employed to convert these by-products to less harmful and/or resalable products. Ceria and ceria based materials are good candidates for the removal and conversion of SOx and NOx. Ceria and ceria related materials are most effective as catalysts when they are in the nano-form with good crystallinity and nanoparticles that are uniform. The growth of nanoparticles is preceded by a nucleation process which can occur by solid-state restructuring of a gel or precipitation from a saturated solution. The precipitation method was selected to synthesize Ceria nanoparticles. Synthesis conditions such as temperature, solution type and ageing time and their effect on the physical and chemical forms of the Ceria particles were investigated. The morphology and structural properties were investigated using Scanning Electron Microscopy, X-ray diffraction and Transmission Electron Microscopy. X-ray Photoelectron Spectroscopy was used to investigate the chemical properties. It was found that low temperatures, low base volume and a solvent with a small dielectric constant favor the formation of small crystallites with a relatively large concentration of defects. These defects are desirable since they enhance the catalytic activity of ceria.