Abstract: Surfaces of fine polystyrene (PS) and polymethyl methacrylate (PMMA) powders were modified by exposure to the downstream products of a nitrogen or oxygen microwave plasma. The effects of nitrogen and indium incorporation in the powder surface were studied with emphasis on variations in the triboelectric properties of the powder. X-ray photoelectron spectroscopy (XPS) was utilized to determine the changes in surface elemental composition. After nitrogen plasma treatment, the C 1s peak profiles suggested the formation of amines in the case of PS, and the formation of imines and amides in the case of PMMA. Oxygen plasma treatment suggested the formation of hydroxyl and carbonyl groups on the surfaces of both PS and PMMA. After treatment with a nitrogen or oxygen plasma, the charge-to-mass ratio (Q/M) of PS and PMMA powders in contact with carrier particles was measured using the cage blowoff method. The surface charge density (Q/A) was calculated from Q/M.

Abstract: Dust in a gas laser, particularly an excimer laser, is removed from the gas charge by one or more electrostatic precipitators that are located inside the laser vessel in the path of gas circulation that is produced by a fan and passes through the discharge area defined by the main discharge electrodes. The gas is caused to travel rapidly past the precipitator so that only a minor proportion of the dust is removed at each pass, but a low background level of dust in the gas is soon achieved and maintained by repeated such passes. This technique of employing multiple passes, each removing only a small percentage of the dust in the gas at any given time, can also be applied to a system in which the precipitator is located outside the vessel and is connected thereto by conduits.

Abstract: Surfaces of fine polystyrene (PS) and polymethyl methacrylate (PMMA) powders were modified by exposure to the downstream products of a nitrogen or oxygen microwave plasma. The effects of nitrogen and indium incorporation in the powder surface were studied with emphasis on variations in the triboelectric properties of the powder. X-ray photoelectron spectroscopy (XPS) was utilized to determine the changes in surface elemental composition. After nitrogen plasma treatment, the C 1s peak profiles suggested the formation of amines in the case of PS, and the formation of imines and amides in the case of PMMA. Oxygen plasma treatment suggested the formation of hydroxyl and carbonyl groups on the surfaces of both PS and PMMA. After treatment with a nitrogen or oxygen plasma, the charge-to-mass ratio (Q/M) of PS and PMMA powders in contact with carrier particles was measured using the cage blowoff method. The surface charge density (Q/A) was calculated from Q/M.

Abstract: Spraying apparatus comprising a shroud in the form of a tube flared at one end and made of electrical insulating material, said shroud adapted for connection to an air supply such that in operation a high velocity air stream issues from the flared end of the shroud, at least one air shear nozzle mounted inside the shroud adjacent the flared end, a tube adapted for connection to a liquid spray source for supplying the nozzle such that in operation the liquid is atomized by the high velocity air flow and the expansion of compressed air from the supply passing over the nozzle, means for maintaining the liquid in the nozzle at ground electrical potential, a high voltage metal electrode positioned inside the flared end of the shroud in spaced relation to the nozzle, and means for supplying high voltage to the electrode such that in operation the electrode carries a high voltage positive or negative potential effective to charge by induction liquid particles or droplets issuing from the said nozzle.

Abstract: A system of corona injection and repelling electrodes are positioned such that airborne particulates are charged in situ and are propelled to collecting grids above a furnace, or concentrated into particle streams directed into ventilation hoods to be collected by low volume, high efficiency precipitators.