I have never gotten serious about this but I remember thinking the idea seemed promising. I thought this might make for good discussion; if feasible maybe an interesting science fair or even an undergrad project if it gets that interesting. We actually played with this a bit many years ago and we did get some encouraging initial results using a very crude apparatus, but we never got back to it. The basic idea is this: Use particulates in place of a moving belt. We used an impeller style fan and motor from a vacuum cleaner. In our first run I believe the fan was grounded. This was used to drive talcum powder through a closed system designed to transfer charge as does the belt in a normal VDG generator. Keeping in mind that it has been a long time, IIRC, and if I was thinking properly, the capacity to transfer charge increases dramatically due to the total surface area available in a dense particle stream. The end effect would be a high power device, surely much more lethal than a normal VDG if it worked as I was thinking. I believe, at least in principle it appeared that that the surface area for charge transfer could be scaled up by orders of magnitude using particulates as compared to the belt transfer method, and given approximately the same size generator column. I assumed that the total power is limited by the size of the fan motor used, insulation issues, and the efficiency of the charge transfer to and from the dust. What actual losses one might find…I couldn’t be sure. AFAIK, this would be very difficult to calculate. Lossy, yes. Too lossy, I don’t know. I kept thinking that I can always use more power and more powder, and more collisions for charge transfer, to beat many problems. Does this offer the means to simply "watt your way" thought the issues [so to speak]. For example, if too many restrictions are placed in the system and they are impedeing the flow of the particulates, use multiple stage fans to increase the pressure. The prices is simply more power in. Note that any combustible materials should be avoided. This could cause an explosion such as we see in grain chutes from time to time. Dust explosions are very, very dangerous!!! In fact someone I knew of in Portland just died in one a few years ago. Dust had gotten into a high voltage panel and it exploded when he opened the door. Anyway, we believed that talcum power was probably safe, but honestly, we didn’t know for sure. What do you think, could it work?