Abstract not available

This thesis investigates the effects of elastic restraint at the supports on the behaviour of shallow concrete arches, and the time-dependent effects of shrinkage and creep of concrete on the nonlinear behaviour of shallow arches. The nonlinear behaviour of shallow circular arches with elastic rotational restraints at each support and subjected to a uniformly distributed radial load is firstly investigated. A virtual work formulation is used to establish both the nonlinear equilibrium equations and the buckling equilibrium equation for shallow arches. The analytical results show that the effects of the stiffness of the rotational restraints on the prebuckling and buckling response are significant. An analytical model is developed for the in-plane elastic stability analysis of shallow parabolic arches with horizontal spring supports subjected to a uniformly distributed vertical load. A parametric study is undertaken using the proposed analytical model. It is found that the effects of the stiffness of the horizontal springs on the prebuckling response, buckling load and buckling behaviour of arches are significant. An analytical model is developed to simulate the time-dependent behaviour of shallow concrete parabolic arches with horizontal spring supports subjected to a sustained loading, and in particular to investigate creep buckling. The time-dependent buckling load and the critical time (or age) of the arches are calculated by using an iterative process based on the proposed model. A systematic parametric study is undertaken, and the results show that the various parameters have a profound effect on the time-dependent buckling load and the prebuckling life of arches. Both short-term and long-term experimental investigations of shallow parabolic tied concrete arches are described and used to validate the analytical models. For the short-term tests, three concrete arches were subjected to a uniformly distributed vertical load and were loaded to failure. For the long-term tests, seven concrete arches were subjected to sustained service loads. The instantaneous and time-dependent deflections were recorded throughout the period of loading, together with the distribution of the horizontal thrust at the supports. Comparisons between the experimental results and the analytical predictions using the analytical models are made to verify the accuracy of the theoretical models.

Background Strategic alliances have become increasingly popular within the business world, they can be seen as a way to improve the total output of the firm. Over the last 10 years, the industry endured trying times, the most notable being the events of September 11, 2001. That event drastically changed airline traveling all across the world. It also showed the importance of collaborations in order to stay competitive. Star Alliance began in 1997 and has since then grown into the world’s largest airline alliance with a total market share of 25.1%. Purpose The raison d’être of this study is to quantify and analyze the augmentation of load factors over time, in terms of distribution, as they pertain to capacity performance of allied carriers within Star Alliance. Method In order to fulfill the purpose, a deductive approach to the research has been taken. Furthermore, due to the nature of the data, a quantitative approach has been used within. Two hypotheses will be stated and several research questions as well. Result It can be clearly seen that distribution of load factors has transformed during the years. There is a shift in both the skewness and the kurtosis of the distributions that can be seen when examining the frequency distribution charts. The kurtosis increases and the skew decreases, measures that are positive for the airlines, while the anomalies of 0% and 100% load factor have remained stable throughout the years. A general increase in the average load factors has also been seen. Conclusion By analyzing the empirical findings, it is clear that the load factor of the allied members has increased and that the proportion of the denied boardings decreased in relation to the average load factor. This means that the alternative hypothesis was accepted in the first hypothesis and that the second alternative hypothesis was accepted in the second hypothesis. The research also reveals a generally increased mean which together with the changes in the skew and kurtosis lead to an acceptance of the beta distribution. Furthermore, higher load factors were shown to have a strong correlation with the increase in efficiency and decrease in overselling.

<p>Background</p><p>Strategic alliances have become increasingly popular within the business world, they can be seen as a way to improve the total output of the firm. Over the last 10 years, the industry endured trying times, the most notable being the events of September 11, 2001. That event drastically changed airline traveling all across the world. It also showed the importance of collaborations in order to stay competitive. Star Alliance began in 1997 and has since then grown into</p><p>the world’s largest airline alliance with a total market share of 25.1%.</p><p>Purpose</p><p>The raison d’être of this study is to quantify and analyze the augmentation of load factors over time, in terms of distribution, as they pertain to capacity performance of allied carriers within Star Alliance.</p><p>Method</p><p>In order to fulfill the purpose, a deductive approach to the research has been taken. Furthermore, due to the nature of the data, a quantitative approach has been used within. Two hypotheses will be stated and several research questions as well.</p><p>Result</p><p>It can be clearly seen that distribution of load factors has transformed during the years. There is a shift in both the skewness and the kurtosis of the distributions that can be seen when examining the frequency distribution charts. The kurtosis increases and the skew decreases, measures that are positive for the airlines, while the anomalies of 0% and 100% load factor have remained stable throughout the years. A general increase in the average load factors has also been seen.</p><p>Conclusion</p><p>By analyzing the empirical findings, it is clear that the load factor of the allied members has increased and that the proportion of the denied boardings decreased in relation to the average load factor. This means that the alternative hypothesis was accepted in the first hypothesis and that the second alternative hypothesis was accepted in the second hypothesis. The research also reveals a generally increased mean which together with the changes in the skew and kurtosis lead to an acceptance of the beta distribution. Furthermore, higher load factors were shown to have a strong correlation with the increase in efficiency and decrease in overselling.</p>

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xiii, 148 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 136-137).

This dissertation first develops a theoretical framework to enable the estimation of cost efficiency and conduct parameter without total cost data. By validating this framework using U.S. airline data, this dissertation shows the feasibility of the theoretical framework. Based on the estimates of marginal cost efficiency and conduct parameter, this dissertation also finds some support for the Quiet Life Hypothesis. In Chapter III, this dissertation analyzes the determinants for price dispersion, especially conduct parameter and cost efficiency. Generally speaking, we find negative relationship between conduct parameter and price dispersion and negative relationship between marginal cost efficiency and price dispersion. In Chapter IV, this thesis examines the dynamics that lead to high price dispersion. To be more specific, this thesis concentrates on advanced days purchased and load factor.

This thesis investigates the effects of elastic restraint at the supports on the behaviour of shallow concrete arches, and the time-dependent effects of shrinkage and creep of concrete on the nonlinear behaviour of shallow arches. The nonlinear behaviour of shallow circular arches with elastic rotational restraints at each support and subjected to a uniformly distributed radial load is firstly investigated. A virtual work formulation is used to establish both the nonlinear equilibrium equations and the buckling equilibrium equation for shallow arches. The analytical results show that the effects of the stiffness of the rotational restraints on the prebuckling and buckling response are significant. An analytical model is developed for the in-plane elastic stability analysis of shallow parabolic arches with horizontal spring supports subjected to a uniformly distributed vertical load. A parametric study is undertaken using the proposed analytical model. It is found that the effects of the stiffness of the horizontal springs on the prebuckling response, buckling load and buckling behaviour of arches are significant. An analytical model is developed to simulate the time-dependent behaviour of shallow concrete parabolic arches with horizontal spring supports subjected to a sustained loading, and in particular to investigate creep buckling. The time-dependent buckling load and the critical time (or age) of the arches are calculated by using an iterative process based on the proposed model. A systematic parametric study is undertaken, and the results show that the various parameters have a profound effect on the time-dependent buckling load and the prebuckling life of arches. Both short-term and long-term experimental investigations of shallow parabolic tied concrete arches are described and used to validate the analytical models. For the short-term tests, three concrete arches were subjected to a uniformly distributed vertical load and were loaded to failure. For the long-term tests, seven concrete arches were subjected to sustained service loads. The instantaneous and time-dependent deflections were recorded throughout the period of loading, together with the distribution of the horizontal thrust at the supports. Comparisons between the experimental results and the analytical predictions using the analytical models are made to verify the accuracy of the theoretical models.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains x, 147 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 117-121).

Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2006. / Includes bibliographical references (p. 65-66).

Thesis (Ph.D.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 171-177.