On Thu, 18 Oct 2001 keyser-soze@hushmail.com wrote:

A specialized ultrasonic device is not required to produce micron fine aerosol powders. All one needs is a used and cleaned print head

In fact not, pressure waves strong enough to aerosol liquid will also cause cavitation, resulting in heating and destruction of material.

assembly and its piezo pulse circuitry. Nozzle apertures are typically 25-50 micron and if the material is suspended, in weak

Ever tried pushing a bacterial suspension through a printer head (processivity set aside)? It will clog it up in no time.

concentration, in a solution which quickly evaporates but doesn't harm the spores it should produce moderate quantities of fine powder quickly.

Um, why don't we quit armchair microbiology, and stick to what we can best: produce lots of uninformed speculations? Oh.

If smaller sizes are desired a field ring charged to 1000-3000v DC can be placed around and in front of the nozzles. If operated in sync with the nozzle pulses it can cause a the emerging droplets to cascade to nanometer size via the electrospray effect (now becoming common in drug production). See http://www.essex.ac.uk/bs/staff/colbeck/index.htm#appas

I think it should be easy enough to look up relevant patents online, assuming one is bored enough.