Effects of combined stressing on the electrical properties of film and ceramic capacitors
Advanced power systems which generate, control and distribute electrical power to many large loads are a requirement for future space exploration missions. The development of high temperature insulating materials and power components constitute a key element in systems which are lightweight, efficient, and are capable of surviving the hostile space environment. In previous work, experiments were carried out to evaluate film and ceramic capacitors for potential use in high temperature applications. The effects of thermal stressing, in air and without electrical bias, on the electrical properties of the capacitors as a function of thermal aging up to 12 weeks were determined. In this work, the combined effects of thermal aging and electrical stresses on the properties of teflon film and ceramic power capacitors were examined. The ceramic capacitors were thermally aged for 35 weeks and the teflon capacitors for 15 weeks at 200/spl deg/C under full electrical bias and were characterized, on a weekly basis, in terms of their capacitance stability and electrical loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also obtained. The results obtained represent the influence that short-term thermal aging and electrical bias, have on the electrical properties of the power capacitors characterized.<<ETX>>
Thermal aging effects on the electrical properties of film and ceramic capacitors
Experiments are carried out to evaluate film and ceramic capacitors for potential use in high temperature applications. The capacitors are characterized in terms of their capacitance stability and dielectric loss in the frequency range of 50 Hz to 100 kHz at temperatures of 20/spl deg/C to 200/spl deg/C. DC leakage current measurements are also obtained as a function of temperature. The effects of thermal stressing, in air and without electrical bias, on the properties of the capacitors are determined as a function of thermal aging up to 12 weeks. The results indicated that short-term aging has minimal influence on the dielectric properties of both the teflon and ceramic type capacitors.
Creating the Virtual Universe
Simulation software is important to our understanding of the universe. The intrinsic multiphysics aspects are spiced with a range of temporal scales and spatial scales, both of which cover more digits than are available in the standard hardware. This, together with the intrinsic chaotic nature of many physical processes, poses quite a challenge. To meet this challenge, researchers developed the Astronomical Multipurpose Environment (AMUSE). Instead of writing a suite of multiphysics solvers from scratch, AMUSE's developers coupled existing solvers for each physical ingredient. The result is a highly inhomogeneous collection of dedicated solvers with a homogeneous protocol that scales to supercomputers.