Recent content by Mister Perfessor

I like this paper, saving it for reference & sharing to anyone who cares I am in the puget sound area, 33 miles from where the virus began inside the US. The local authorities have been advising DIY mask-makers to test their choice of fabric by running it quickly under cold water from a...

I actually forgot that one little detail! Those last few replies sort of got me off track. Being that discussion of mask or respirator design isn't really the subject of this thread, I probably should have put that into a new post But how this thread does apply to my PAPR project remains the...

That's nice, but this thread was about DIY masks. And more specifically, asking about the levels of formaldehyde that might be found in commonly available materials such as Shop Tool brand paper towels sold by Harbor Freight The particle size being stopped by shop towels is a subject of the...

I read that cambridge report. Suay Sew Shop is trying to do the same kind of testing using some more interesting fabric choices than just plain cotton. But the testing will cost around $40,000

I read the entirety of that article. It does not appear to be so cut & dry that all N95 masks in general ought to be regarded as low-level sources of formaldehyde. In fact, that article makes me think that the professionally made masks might have a random choice of low-level or zero-level...

I agree with that, as the coefficient of friction between the tire's contact patch and the road surface is a variable, and that very aggressive braking will alter that state dramatically. Temperature rise inside the tire & the road surface play a very important role Just consider the brake pads...

I should've spotted this mistake sooner! I think you have considered the static friction keeping a tires contact patch from slipping across the road surface, as being the frictional forces which are inside the wheel bearings? Where a rolling tire involves the coefficient of static friction is...

I think you may have left out one important detail in the stated quote from your physics teacher: "If you lock your wheels driving down the road on dry concrete if they are sliding, or skidding, you will have less friction than if they are rolling" I think that what your teacher had meant to...

The Tumbling Bananas do not stop for lunch:

Oh yes, I must! But that is an interesting alternate idea. Might even work better for some artistic applications I was considering If you should happen to look at an example of the 'Lumin' plasma disk, you will see that they are using a pair of glass disks, bonded together. The OP's question...

I hadn't considered the cleanliness of the glass. But then, I haven't built these sort of things before My original search was to find the same sort of answers like the OP's question on this thread. Ideally a website like Instructables. I suppose I should search that one directly I'm getting...

Thanks. And, what about this: just how close together can the plates be & still work as a plasma discharge lightshow? Could one of the plates be used as the rear wall of an aquarium, to any useful effect? Could a upward facing plasma disk be used to influence the motion of a pendulum? Can a...

Yes I know it's an old thread. But I just thought it was a shame nobody cared enough to provide a solution. Who knows, maybe somebody else may come along looking for more information? I did, and this was only the 15th search result on the 1st page. I usually don't call it until at least 50 pages...