Inertial Energy Storage for Spacecraft

The feasibility of inertial energy storage in a spacecraft power system is evaluated on the basis of a conceptual integrated design that encompasses a composite rotor, magnetic suspension and a permanent magnet (PM) motor/generator for a 3-kW orbital average payload at a bus distribution voltage of 250 volts dc. The conceptual design, is referred to as a Mechanical Capacitor. The baseline power system configuration selected is a series system employing peak-power-tracking for a Low Earth-Orbiting application. Power processing, required in the motor/generator, provides potential alternative that can only be achieved in systems with electrochemical energy storage by the addition of power processing components. One such alternative configuration provides for peak-power-tracking of the solar array and still maintains a regulated bus, without the expense of additional power processing components. Precise speed control of the two counterrotating wheels is required to reduce interaction with the attitude control system (ACS) or alternatively, used to perform attitude control functions

Beyond Prejudice and Pride: The Human Sciences in Nineteenth and Twentieth Century Latin America

Grappling with problematics of status and hierarchy, recent literature on the history of the human sciences in Latin America has gone through three overlapping phases. First, the scholarship has reflected a dialogue between Latin American scientists and their European colleagues, characterized by the “center/periphery” model of scientific diffusion. Next, scholars drew on postcolonial theory to undermine the power of the “center” and to recover the role of local agents, including both elites and subalterns. In the wake of numerous studies embracing both models, the way has been cleared to look at multiple dimensions simultaneously. Histories of the human sciences in the complex multicultural societies of Latin America provide an unusually direct path to integration. Moreover, this dynamic and multilayered approach has the potential to address ambivalences about authority and power that have characterized previous analyses of the production and application of knowledge about the human condition