Radially rotating miniature heat pipes for turbine blade cooling applications

Aerospace turboengines present a demanding challenge to many heat transfer scientists and engineers. Designers in this field are seeking the best design to transform the chemical energy of the fuel into the useful work of propulsive thrust at maximum efficiency. To this aim, aerospace turboengines must operate at very high temperatures and pressures with very little heat losses. These requirements are often in conflict with the ability to protect the turboengine blades from this hostile thermal environment. Heat pipe technology provides a potential cooling means for the structure exposed to high heat fluxes. Therefore, the objective of this dissertation is to develop a new radially rotating miniature heat pipe, which would combine the traditional air-cooling technology with the heat pipe for more effective turboengine blade cooling. ^ In this dissertation, radially rotating miniature heat pipes are analyzed and studied by employing appropriate flow and heat transfer modeling as well as experimental tests. The analytical solutions for the flows of condensate film and vapor, film thickness, and vapor temperature distribution along the heat pipe length are derived. The diffuse effects of non-condensable gases on the temperature distribution along the heat pipe length are also studied, and the analytical solutions for the temperature distributions with the diffuse effects of non-condensable gases are obtained. Extensive experimental tests on radially rotating miniature heat pipes with different influential parameters are undertaken, and various effects of these parameters on the operation of the heat pipe performance are researched. These analytical solutions are in good agreement with the experimental data. ^ The theoretical and experimental studies have proven that the radially rotating miniature heat pipe has a very large heat transfer capability and a very high effective thermal conductance that is 60–100 times higher than the thermal conductivity of copper. At the same time, the heat pipe has a simple structure and low manufacturing cost, and can withstand strong vibrations and work in a high-temperature environment. Therefore, the combination of the traditional air-cooling technology with the radially rotating miniature heat pipe is a feasible and effective cooling means for high-temperature turbine blades. ^

Adaptation of trailing spouses: Does gender matter?

The adaptation to a new country is a complex and stressful process that is compounded when changes in status and identity have to be made. This exploratory study examined the adaptation of international company transferee spouses when they decide to follow the transferee on overseas assignments. Research to date indicates that the spouses’ dissatisfaction with life abroad is the leading cause of transferees breaking contract and prematurely returning home. The causes of this dissatisfaction are still not clear and this study sought greater clarification, particularly examining the experiences of male as well as female trailing spouses. The study, thus, takes gender as a main variable to consider. It explores how gendered expectations inherent in the structures of society inflect and inform the decisions, attitudes, and behaviors that affect the adaptations of trailing spouses living in a foreign habitus. The study is based on eight months of ethnographic research in two culturally different locations, Kuala Lumpur, Malaysia and Brussels, Belgium. Forty-two American international company transferee spouses were recruited (seven males and thirty-five females). The data analysis revolved around five main themes: (1) the comparison of male with female trailing spouses’ experiences, (2) the effect of location on spouses’ adaptation, (3) the communities that spouses integrate into, (4) variations in personal work and family histories, and (5) conditions of exit. The analysis engaged multiple theories regarding gender, sociological adaptation, and psychological adaptation. Results indicate that both socio-cultural and psychological factors affect adaptation and that gender matters very significantly, particularly along two axes: (1) gendered structures in our society create different reasons why males and females become trailing spouses, (2) the gendered social constructions of role expectations make the experience of being a trailing husband different from being a trailing wife. In addition spouses’ status as parents (or not) and their “readiness for change” were found to be important predictors of positive spousal adaptation. In contrast, significant ties with families in the home country and strong professional identity with career projections were important predictors of negative spousal adaptation.

Politics at the water's edge: The presidency, Congress, and the North Korea policy of the United States

For all their efforts to avoid a nuclear North Korea, the Clinton and Bush administrations failed to achieve this goal, the most important policy objective of the United States in its relations with North Korea for decades, mainly because of inconsistencies in U.S. policy. This dissertation seeks to explain why both administrations ultimately failed to prevent North Korea from going nuclear. It finds the origins of this failure in the implementation of different U.S. policy options toward North Korea during the Clinton and Bush administrations. To explain the lack of policy consistency, the dissertation investigates how the relations between the executive and the legislative branches and, more specifically, different government types—unified government and divided government—have affected U.S. policy toward North Korea. It particularly emphasizes the role of Congress and partisan politics in the making of U.S. policy toward North Korea. This study finds that divided government played a pivotal role. Partisan politics are also central to the explanation: politics did not stop at the water’s edge. A divided U.S. government produced more status quo policies toward North Korea than a unified U.S. government, while a unified government produced more active policies than a divided government. Moreover, a unified government with a Republican President produced more aggressive policies toward North Korea, whereas a unified government with a Democratic President produced more conciliatory policies. This study concludes that the different government types and intensified partisan politics were the main causes of the inconsistencies in the United States’ North Korea policy that led to a nuclear North Korea.

Measuring Hotel Service Quality: Tools for Gaining the Competitive Edge

As the hotel industry grows more competitive, quality guest service becomes an increasingly important part of managers' responsibility measuring the quality of service delivery is facilitated when managers know what types of assessment methods are available to them. The authors present and discuss the following available measurement techniques and describe the situations where they best meet the needs of hotel managers: management observation, employee feedback programs, comment cards, mailed surveys, personal and telephone interviews, focus groups, and mystery shopping.

Adaptation of Trailing Spouses: Does Gender Matter?

The adaptation to a new country is a complex and stressful process that is compounded when changes in status and identity have to be made. This exploratory study examined the adaptation of international company transferee spouses when they decide to follow the transferee on overseas assignments. Research to date indicates that the spouses’ dissatisfaction with life abroad is the leading cause of transferees breaking contract and prematurely returning home. The causes of this dissatisfaction are still not clear and this study sought greater clarification, particularly examining the experiences of male as well as female trailing spouses. The study, thus, takes gender as a main variable to consider. It explores how gendered expectations inherent in the structures of society inflect and inform the decisions, attitudes, and behaviors that affect the adaptations of trailing spouses living in a foreign habitus. The study is based on eight months of ethnographic research in two culturally different locations, Kuala Lumpur, Malaysia and Brussels, Belgium. Forty-two American international company transferee spouses were recruited (seven males and thirty-five females). The data analysis revolved around five main themes: (1) the comparison of male with female trailing spouses’ experiences, (2) the effect of location on spouses’ adaptation, (3) the communities that spouses integrate into, (4) variations in personal work and family histories, and (5) conditions of exit. The analysis engaged multiple theories regarding gender, sociological adaptation, and psychological adaptation. Results indicate that both socio-cultural and psychological factors affect adaptation and that gender matters very significantly, particularly along two axes: (1) gendered structures in our society create different reasons why males and females become trailing spouses, (2) the gendered social constructions of role expectations make the experience of being a trailing husband different from being a trailing wife. In addition spouses’ status as parents (or not) and their “readiness for change” were found to be important predictors of positive spousal adaptation. In contrast, significant ties with families in the home country and strong professional identity with career projections were important predictors of negative spousal adaptation.