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CCI Valve Technology AB is a company located in Säffle, Sweden, that manufactures and installs bypass valves. Due to requirements outside normal standards on the valve's hardness values, some measurements have had difficulties meeting such requirements. During this thesis work, tests were carried out to determine how to overcome the difficulties. The experiments focused on five different areas that may affect the components hardness, welding method, soaking temperature during post weld heat treatment, measuring procedure, component thickness and number of heat treatment cycles. The Grade 91 steel specimens that were examined consisted of five solid cylinders and three various pipes that were welded together by using shielded metal arc welding (SMAW) or gas tungsten arc welding (GTAW). Each pipe was sawed apart into three equal parts. All specimens were hardness tested and eight of the specimens' microstructure was studied with an optical microscope. The hardness measurement instruments used, LECO V-100-C2 and GE-MIC 10, are Vickers hardness testers, one stationary and the other one portable. The measuring results contain a vast number of different hardness measurement data. From the analyzed data, the conclusions were drawn that the most suitable soaking temperature during post weld heat treatment were 750° C, that the SMAW method creates a more stable hardness profile than the GTAW method, and that one heat treatment cycle is more beneficial than two or more.

Les particularités de climat et les nouveaux avions très gros porteurs, imposent des effets cycliques dangereux sur les couches de roulement. Les simulations en laboratoire de ces phénomènes ont montrées leur influence sur les qualités viscoélastiques du bitume et enrobé, qui sont fonctions des variations de la température. Telles que les déformations permanentes avec perte de résistance et le durcissement du bitume associé au vieillissement accéléré. Les lois de comportement en fatigue sous trafic prouvent que les grandes amplitudes de déformation en tandem endommagent sévèrement l’enrobé. Les informations recueillies permettent de mieux prévoir l’évolution du comportement in situ du bitume et enrobé. / Abstract

M.Com. (Economics) / Please refer to full text to view abstract

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Deserted and disintegrating barns, houses, and silos have always perplexed me when driving through the country. I am fascinated by how this leisurely decay reveals their structural integrity in a slow, reverse process of construction. It is as if humanity and nature consciously collaborated to create these gigantic memento mori for a steady stream of highway viewers. These monumental tributes to inevitable decline, along with my own adventures in gardening, childrearing, eldercare, and travels, have led me to explore the universal cycles of life. The dilapidated buildings in my work are rendered in a tight, sharp, close-up viewpoint so that the viewer is forced to engage them. I will often layer images of seeds, leaves, and rocks on top of images of houses to symbolize the different stages of the life cycle. I see seeds and buildings as containers and incubators of potential. Any foliage represents a fulfillment of that potential, while rocks stand for the fossilized remains, or the achievements of one’s life accomplishments.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

M.Comm. / There are many different opinions among economists around the validity and existence of the business cycle. It varies from the total nullification of the existence of a business cycle to the founding of a working definition in this regard. One of the characteristics of the South African economy and similar capitalist systems is an unstable business environment. Periods of economic growth are followed by periods of economic recession when employment, production, prices, profits and general economic welfare are in decline. These phases are known as the business cycle. Economists differ from the early days with relation to the factors that led to changes in total economic activity. Classical economists focussed on the supply side factors as the main cause of the business cycle. John Keynes criticized the early models and presented a model in which change in output is largely dependent on changes in aggregate demand. The latest theory is known as the Real Business Cycle and includes both the supply and demand side factors. The emphasis is, however, on the supply side and argues that changes in the aggregate supply are the main determining factor in economic contraction or expansion. Between 1946 and 1996, 14 complete cycles occurred in the South African economy. The total cycle comprises of the first upward phase, the second upward phase, the first downward phase and the second downward phase. Specific indicators are present during each phase. Car sales are determined by demand. The demand include consumer preference, income, the price of competing or similar goods, expectations of the consumer, availability of credit, consumer confidence as well as the price of the product. The single most important influence on car sales is political stability, economic growth and interest rates. These factors determine the extent of consumer confidence. The occurrence of business cycles in the South African economy and the cyclical tendency of car sales are largely in tandem. Of the 14 upward and onward phases since 1960, 12 phases show positive correlations. This means that car sales represent an adequate barometer with regard to the state of economic activity as a whole in the country. It is also an effective barometer regarding expected future developments on the economic front. The state of the business cycle can be of tremendous value regarding planning in the motor manufacturing industry. The specific phase in which the business cycle is, will provide a sound indication of what kind of success might be anticipated with regard to future sales.

OBJECTIVES: To determine and compare color difference CIEDE2000 (ΔE00) of pressed IPS E.max lithium disilicate ceramic material after repeated firing cycles. To determine and evaluate correlation of CIELAB and CIEDE2000 values analyzed by X-Rite Color i5 Spectrophotometer, VITA EasyShade® Advance 4.0 (VITA Zahnfabrik) and Adobe Photoshop CC. MATERIALS AND METHODS: 36 specimens 8mmX10mm at 1.5mm thickness (12 specimens of pressed IPS e.max® Press Lithium Disilicate MT Monochromatic ingots and 24 specimens pressed IPS e.max® Multi Press Lithium Disilicate Multichromatic ingots. Specimens were exposed to repeated firing cycles up to 7 cycles. Color analysis was performed after 1st,2nd,3rd,5th, and7th firing cycle. CIE L*a*b* values measured by X-Rite Color i5 Spectrophotometer, VITA EasyShade® Advance 4.0 (VITA Zahnfabrik) and Adobe Photoshop CC. CIELAB (Δ*ab) and CIEDE2000 (Δ00) calculated to measure color difference. RESULTS: Linear regression and multiple comparison analysis (Tukey’s HSD test) showed a significant color difference (Δ*ab) and CIEDE2000 (Δ00) with (p-value <0.001), after multiple firing cycles, between instruments used and in different shades groups. Moreover, significant different in interactive effect between different shades tested by different instrument, different shades tested after multiple firing cycles and different instruments after multiple firing cycles. CONCLUSION: IPS E.max lithium disilicate material shows significant color difference after repeated firing cycle tested by three color analysis instruments. Measuring instruments used to evaluate CIE L*a*b* color values showed significant different in color values analysis which may lead to altered level of interpretation, particularly to determine perceptibility and clinical acceptability thresholds. / 2021-08-15T00:00:00Z

Capital structure is the varying levels of use of debt and equity to finance a firms operations. Firms have an overall leverage level, consisting of a long term and short term level. The economy has different phases over the business cycle ranging from boom cycles where businesses prosper to recessions when they may have difficulties. This cycle can be identified utilising economic indicators, the South African Reserve Bank has classified time periods into growth and recessionary periods, this business cycle phase allocation was utilised for this study to mark recessions. Specific industries from the JSE were selected in an attempt to answer the study’s hypotheses of industry capital structure heterogeneity and that recessions affect capital structure. A sample period from 1995 until 2012 was utilised, containing 5 recessionary years. A stable industry, farming and fisheries, a highly variable industry, the heavy construction industry and a new age industry, the computer services industry, were selected. The results of the study suggested that capital structure varies across industries as evidenced by the mean differences of leverage for total debt, long term debt and short term debt being statistically significant. The computer services industry utilised the least debt over all. The industries all showed a preference for the use of short term debt. Panel data analysis following both Fixed Effect Methodology and Random Effect Methodology was conducted to analyse the firm-specific factors which affect capital structure as well as the use of a dummy variable to capture the effects of recessions. The firm-specific effects under study included asset tangibility, tax, profitability, age and size. South African firms follow a pecking order as shown by the negative relationship observed between profitability and long and short term debt ratios. Existence of weak evidence in this study shows that recessions affect the capital structure of some of the industries studied. The computer services industry is clearly affected, while farming and fisheries industry has very weak evidence that long term debt may be affected, while there is no evidence to show that the heavy construction industry is affected at all. The study concluded with accepting the hypothesis that there are capital structure variations across industries, which are listed on the JSE in boom and bust periods.