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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Glaze Exploration via Nostalgic Locations

Williams, Robert A. 01 November 2018 (has links)
In my art practice, collecting materials from personally significant locations has become a way to subtly reconnect people with places, nature, natural materials and processes. I produce well-made objects, with the end goal of allowing the viewer to feel and interact with traditional forms of beauty through craft, which is increasingly rare in our mechanized world. Raw materials are a direct link to nature and earth, a link which people in general can benefit from in essential ways. The processes of collecting and using naturally occurring materials to form links between objects and places resembles human relationships, and the connections between places, things, and people set the stage for the performance of beauty.
22

Characterization of Ceramic Raw Minerals in Uganda for Production of Electrical Porcelain Insulators

Olupot, Peter Wilberforce January 2010 (has links)
In this work an extended literature survey on ceramics and porcelains in particular, has been documented. Samples from two Ugandan deposits of each feldspar and quartz were characterised by means of X-ray diffraction, thermal analysis, chemical analysis and scanning electron microscopy and found to possess requisite properties for making electro porcelain insulators. Five porcelain bodies were formulated and samples were fabricated from materials collected from selected deposits in Uganda using different mixing proportions of clay, feldspar and quartz. The properties of the formulated bodies were studied in relation to workability, firing temperature, dielectric and bending strengths. The strengths (both mechanical and dielectric) were found to decrease as the firing temperature was increased above 1250°C. Additionally, ten formulations with components in the range of 30-60% clay, 20-45% feldspar and 20-25% sand were prepared. Specimens for mechanical and physical characterisation were made using the plastic extrusion method. The samples were characterised in terms of constituent oxide composition, flexural strength, fracture toughness, dielectric strength along with microstructural and phase properties using ICP-AES analyses, 4-point load bending strength test, Vicker’s indentation method, SEM and XRD analyses respectively. XRD studies revealed that the crystalline phases formed were mullite and quartz and their intensity was almost identical for all samples fired at 1250°C but there was a decrease inquartz content as temperature was increased above 1250°C. Samples with 20% sandcontent resulted in higher density, MOR and fracture toughness compared to thosecontaining 25% sand. Mullite content on the other hand did not change at temperatures above 1200°C but there were significant differences in the morphologies of the mullite crystals in the samples. Optimum mechanical and electrical properties were found at maximum vitrification and a microstructure showing small closely packed mullite needles. This occurred at a firing temperature of 1250°C. Three promising porcelain formulations from the above investigations were chosen and five glazes formulated to fit on biscuit fired specimens. The best-fitting glaze was adopted. The formulated specimens were investigated using dilatometry, Steger test, FEG-SEM, XRD, 4-point bending, dielectric strength and fracture toughness tests. A porcelain specimen consisting of 68% SiO2, 19% Al2O3, 4.7% K2O and a glaze of Seger formula RO:0.57Al2O3:4.86SiO2 exhibited MOR of 105MPa with Weibull modulus of 5.6 and a dielectric strength of 18kV/mm upon firing at a heating rate of 6ºC/min to 1250ºC, soaking for 2h at the top temperature and cooling down to 500°C at a rate of 6°C/min, followed by furnace cooling. The microstructure of the high strength specimen exhibited round mullite needles, quartz and glass. Holding samples for 2h at peak temperature resulted in a 22% increase in MOR compared to 1h holding. Glazing further improved strength by 67% for the best sample. Compressive stresses in glaze contributed to the strengthening effect. The dielectric and mechanical strengths obtained make the ormulated sample suitable for application in low voltage electrical insulation. / QC20100609
23

Détermination de la résistance à la traction de la glace atmospherique /

Tremblay, Christian, January 1991 (has links)
Mémoire (M.Sc.T.)-- Université du Québec à Chicoutimi, 1991. / Bibliogr.: f. 61-65. Document électronique également accessible en format PDF. CaQCU
24

Étude des propriétés mécaniques en cisaillement de la glace atmospherique /

Bilodeau, Julien. January 1996 (has links)
Mémoire (M.Ress.S.)--Université du Québec à Chicoutimi, 1996. / Document électronique également accessible en format PDF. CaQCU
25

Contribution to study of visible discharge initiation and development on the ice surface = Contribution à l'étude de l'apparition et du développement des décharges visibles à la surface de la glace /

Brettschneider, Stephan, January 2000 (has links)
Thèse (D.Eng.)--Université du Québec à Chicoutimi, 2000. / Document électronique également accessible en format PDF. CaQCU
26

A 2-D random walk model for predicting ice accretion on a cylindrical conductor + : Modélisation en 2-D de l'accumulation de glace sur un conducteur cylindrique par la méthode du cheminement aléatoire /

Chen, Yongmin, January 2001 (has links)
Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 2001. / Document électronique également accessible en format PDF. CaQCU
27

Étude de l'adhérence de la glace sur des solides à caractère glaciophobe /

Laforte, Caroline, January 2001 (has links)
Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 2001. / Document électronique également accessible en format PDF. CaQCU
28

Analyse de la phase de maintien de différents types de glace atmosphérique sur des cables /

Gouzy, Sophie, January 2002 (has links)
Thèse (M. Eng.) -- Université du Québec à Chicoutimi, 2002. / Bibliogr.: f. 154-192. Document électronique également accessible en format PDF. CaQCU
29

Simulation de l'accrétion de glace sur un obstacle bidimensionnel par la méthode des bissectrices et par la modélisation des ruisselets et des gouttes de surface /

Fortin, Guy, January 2003 (has links)
Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2003. / Bibliogr.: f. [211]-216. Document électronique également accessible en format PDF. CaQCU
30

Étude de l'interaction des ondes de choc avec la glace à l'interface air-glace /

Richer, Raynald, January 2003 (has links)
Thèse (Sc.A.) -- Université du Québec à Chicoutimi, 2003. / Bibliogr.: f. [81]-84. Document électronique également accessible en format PDF. CaQCU

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