The problem of attitude control of a flexible satellite using magnetic attitude control is investigated. The work is motivated by JC2Sat - a joint CSA and JAXA mission whose main purpose is a proof of concept of two satellites performing differential drag formation flying. The impact of additional flexible drag panels (of various sizes) on the attitude control is assessed. JC2Sat's attitude control system consists of three perpendicular magnetorquers and one reaction/bias-momentum wheel. Four Linear Quadratic Regulator controllers are compared, ranging in complexity from being time-invariant and assuming a rigid satellite, to being periodic and actively suppressing panel vibrations. These include the first controllers which use magnetic attitude control to actively suppress vibrations, and where the periodic vibration suppression controller is able to guarantee asymptotic stability of the linearized system. It was found that for larger panels, the controllers which actively suppressed the vibrations outperformed those that did not.

Attitude control of spacecraft in low Earth orbits can be achieved by exploiting the torques generated by the geomagnetic field. Recent research has demonstrated that attitude stability of a spacecraft is possible using a linear combination of Euler parameters and angular velocity feedback. The research carried out in this thesis implements a hybrid scheme consisting of magnetic control using on-board dipole moments and a three-axis actuation scheme such as reaction wheels and thrusters. A stability analysis is formulated and analyzed using Floquet and Lyapunov stability theorems.

The problem of attitude control of a flexible satellite using magnetic attitude control is investigated. The work is motivated by JC2Sat - a joint CSA and JAXA mission whose main purpose is a proof of concept of two satellites performing differential drag formation flying. The impact of additional flexible drag panels (of various sizes) on the attitude control is assessed. JC2Sat's attitude control system consists of three perpendicular magnetorquers and one reaction/bias-momentum wheel. Four Linear Quadratic Regulator controllers are compared, ranging in complexity from being time-invariant and assuming a rigid satellite, to being periodic and actively suppressing panel vibrations. These include the first controllers which use magnetic attitude control to actively suppress vibrations, and where the periodic vibration suppression controller is able to guarantee asymptotic stability of the linearized system. It was found that for larger panels, the controllers which actively suppressed the vibrations outperformed those that did not.

Photocopy of typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1974. / Bibliography: leaves 131-137. / vii, 137 leaves ill

Typescript. / Bibliography: leaves 145-160. / xvii, 324 l graphs, tables

Thesis (M.A.)--University of Hawaii at Manoa, 2000 / Pacific Islands Studies

Despite the considerable existing body of academic literature, increasing employee motivation for environmental endeavors continues to be poorly understood. Recently Govindarajulu and Daily (2004) presented a comprehensive theoretical framework for environmental performance by looking at the crucial employer and employee factors affecting environmental performance. The authors identified management commitment, employee empowerment, feedback and review, and rewards as key human resource (HR) factors in increasing employee motivation for enhanced environmental performance. However, no published studies to date have empirically validated the framework. Therefore, one purpose of this dissertation is to address this void. Additionally, job satisfaction and organizational commitment were proposed as mediators in the relationship between the HR factors and environmental performance.

Thesis (Ph. D.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 81-86). Also available online.

Thesis (Ph. D.)--University of Toronto, 2004. / Adviser: Nina Bascia. Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karol inst., 2003. / Härtill 4 uppsatser.