Payload Positioning System for Gravity Gradient Satellite

Many current satellites rely on active control systems to maintain attitude. Passively controlled gravity gradient satellites cost less and are more reliable, but have difficulty accommodating independently moving payloads such as pointable telescopes. To eliminate these difficulties, use of a counter rotating inertia is proposed to negate payload induced transient instabilities. Counter rotating inertias have been used before with limited success due to residual torque/momentum. In gravity gradient satellites, this is absorbed by the gravity gradient restoring torques. A single axis (of a three axis) demonstration gimbal using a bifilar pendulum with PC controlled servo feedback loop and simulated pointable payload was designed and tested. Results without momentum compensation resulted in large excursions and pointing stability problems. Measured displacements using the counter rotating inertia momentum compensation system were within specified and predicted values

Performing the high-school prom in the UK: Locating authenticity through practice

The purpose of this study was threefold: to develop an understanding of the appropriation of the US High School Prom in the UK and more importantly to generate an insight into the producers and consumers of such an event; to establish if the performance of the prom is hyper-real or if there is an awareness of the authentic or inauthentic elements of this ritual and finally to ascertain local interpretation of authenticity and glocal practice. The method used here was a qualitative approach employing 24 in-depth interviews with young adults (18-20 years) who had attended a prom in the UK in the last three years. The findings illustrated that the role and the social network of the individual was key to engagement with the High School Prom and also indicated a possible symbiosis of the strands of theory associated with authenticity. Diverse localised meanings of the prom performance were also identified. As the school prom is a growth market in the UK businesses should be aware of adolescents’ desire for ownership of this event and should tailor their marketing accordingly

The emergence of social enterprises through the initiative of self-organized citizens: an analysis starting from Olson's approach to the logic of collective action

This article provides indirect empirical evidence with which to verify whether the logic of collective action maintained by Olson represents a sound theoretical approach to social enterprises. Our hypothesis is that, if a positive effect of participation in social enterprises on pro-social attitudes of members exists, when considering these organizations we should move from the approach proposed by Olson to the one proposed by Putnam, in the Tocqueville tradition. Overall, the existing empirical and experimental evidence seems to suggest that Putnam's approach to voluntary organizations is better able than Olson's to capture the organizational behavior of social enterprises, confirming that initiatives by self-organized citizens should be considered a possible convincing explanation for their emergence