Geostationary Operational Environmental Satellite (GOES-N report). Volume 2: Technical appendix

The contents include: operation with inclinations up to 3.5 deg to extend life; earth sensor improvements to reduce noise; sensor configurations studied; momentum management system design; reaction wheel induced dynamic interaction; controller design; spacecraft motion compensation; analog filtering; GFRP servo design - modern control approach; feedforward compensation as applied to GOES-1 sounder; discussion of allocation of navigation, inframe registration and image-to-image error budget overview; and spatial response and cloud smearing study

NASA Tech Briefs, June 1997

Topics include: Computer Hardware and Peripherals; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Books and Reports

Study on Attenuation Properties of Surface Wave of AE Simulation Source Based on OPCM Sensor Element

It is of great significance to grasp the ultrasonic attenuation characteristics of materials for the nondestructive testing of materials. The dynamic properties of a piezoelectric composite material (OPCM) with self-developed transverse anisotropy have been analyzed using the experiment in this work. The OPCM sensor is attached to the surface of the iron plate and concrete structures to sense the surface waves generated by acoustic emission (AE). The experiment results show that OPCM sensor elements have unique advantages compared to piezoelectric ceramic materials (PZT). Further, by comparing the signals of isotropic and anisotropic materials, the attenuation characteristics of surface waves propagating in different materials are studied, and a new method for measuring the attenuation coefficient of surface waves is demonstrated