A method for generating a microbial filter of sufficient catalytic density and thickness to increase replenishment interval, improve bacteria attachment and detachment characteristics, and provide endogenous stability under in situ conditions. A system for in situ water remediation. In gated field emitters, electron emission must be initiated at the lowest possible voltage. The composition of the emitter and the gate and the structure of the emitter gate are essential to low-voltage initiation. This method of sharpening the emitter tips uses the grid as a counter electrode in electroetching the emitters and can produce extremely sharp emitter tips and remove asperities and other imperfections in the emitters in relation to the specific grid hole in which the emitter resides.
Emissions thus become more uniform among the emitters, and turn-on voltage is lowered.
A two-stage catalyst composed of an oxidative first stage and a reductive second stage. The first stage is intended to convert nitrogen oxide to nitrogen dioxide in the presence of oxygen. The second stage serves to convert nitrogen dioxide to environmentally benign gases that include diatomic nitrogen, carbon dioxide, and water. A device for isolating seed crystals during processing of solutions. The device enables a seed crystal to be introduced into the solution without exposing the solution to contaminants or to sources of drying and cooling.