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The application of electrostatic technology to the protection of optical components in earth-mounted and satellite orbital systems has been investigated. Theory and experiment indicate it is quite practical to prevent dust deposition in an earth environment. A mathematical analysis indicates even better results should be obtained in an orbital vehicle.

Electrostatic techniques can be used to keep dust and aerosols from depositing on optical components. The system makes use of a corona discharge and a safety screen, located out of the optical path, to charge the incoming dust and then push it away from the optical surface. The system is effective for the dust particles normally found in the atmosphere, there are no exposed high voltage components or moving parts, and power consumption is quite limited.

The application of electrostatic techniques has been investigated as a repulsion system to keep dust off mirrors that might be used in high-power laser systems. A demonstration unit for a 30 cm mirror was built and shipped to Kirtland Air Force Base as part of the program. Other efforts investigated the development of technology that might be used to keep dust and contaminants off large mirrors in an orbiting space platform. If there is dust deposition it may be practical to clean the reflecting surfaces with a dry wipe-off system without damaging delicate coatings or metal films. (Author)

We have developed ways to utilize discarded tires for erosion control structures, bank stabilization and slope stabilization and erosion control in the form of engineered structures for each of these applications. This paper also describes and illustrates a channel erosion control structure made entirely from individual tires used to form side walls, wing walls and aprons for the structure. In this case the individual tires were bound together with nylon rope to form a flexible structure. This structure was built in a ephemeral wash (gully) on a local ranch near Tucson, AZ and has been in place for over ten years.

New applications of electrostatics to the control of dust are investigated. Technology for pushing systems to keep dust off optical systems and move particulates out of airstreams are discussed. Other electrostatic techniques for removal of water droplets and smoke are investigated.

The impact of fine particles and organic contamination on device yield is very serious. We have investigated several technologies in this area. They include: 1) Application of thermophoresis for the prevention of surface contamination. 2) The use of electrets for collection of particles that might otherwise settle on surfaces. 3) The use of dry ice snow as a cleaning medium for the removal of particulates and organic contamination.