Materials Science

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Mark
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Materials Science

Post by Mark » Mon Dec 26, 2005 5:48 pm

How about some volcanic basalt? I wonder if they make a line of swimwear in this fabric?
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Mark
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re: Materials Science

Post by Mark » Mon Dec 26, 2005 6:15 pm

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Stuart
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Re: Materials Science

Post by Stuart » Mon Dec 26, 2005 6:32 pm

Mark wrote:How about some volcanic basalt? I wonder if they make a line of swimwear in this fabric?
Mark
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Thanks for the link. I've been looking for a source. I've been using some header heat wrap.
I'm writing an automated airplane designer in java, useful later when you guys get ready to bolt a p-jet onto some wings

Mark
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re: Materials Science

Post by Mark » Sat Jan 28, 2006 4:13 pm

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re: Materials Science

Post by Mark » Sun Jan 29, 2006 2:22 am

I was imagining that it would be fun to coat my quartz tubing with titanium compounds. In that way I could have the most colorful pulsejet and I could also win the Kitsch award too maybe.
Mark
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I like this effect.
http://www.kellerartglass.com/html/dichroic.html
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Mark
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re: Materials Science

Post by Mark » Sun Jan 29, 2006 2:36 am

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Dang911
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re: Materials Science

Post by Dang911 » Sun Jan 29, 2006 5:36 am

Back to the Aerogel. If it were possible, coat the outside of a pule jet in aerogel, this would not only make it much more efficient, and cool/safe, it would also knock down the noise substantially. 1/4-1/2" coating would be sufficient to have those benefits.

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Dang911
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re: Materials Science

Post by Dang911 » Tue Jan 31, 2006 6:30 pm

Really, well then why is it louder standing in front of the engine, then behind it, in the flow of its exhaust gasses?

Noise isn't just admitted from the intakes and exhausts; it comes from the actual combustion chamber. I have noted in fact, much less noise coming from the actual engines openings. Aerogel has proved to be quite a thermal insulator, but also is a very at impeding sound.
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Dang911
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re: Materials Science

Post by Dang911 » Wed Feb 01, 2006 3:31 am

I'm not saying the metal is making the noise. The greatest intensity of noise happened to mainly come from the combustion chamber, as noted by my observations.

Yes adding this layer of Aerogel will substantially raise the engines operating temperature, but at the same time, why not coat the inside of the pipes also. New nano technology is proving beneficial in the field of corrosion prevention of metal. New processes and technology's have now been developed which make it possible to coat a pipe or other solid metal surface with nano tubes. I'm unsure if this can be done specifically with Aerogel, but its a thought.
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larry cottrill
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re: Materials Science

Post by larry cottrill » Wed Feb 01, 2006 3:15 pm

Dang -

It was Eric who posted his observation (and he is a good observer!) last year that the noise at the side of one of his valveless pulsejets was much greater than the noise on axis behind the tail end. Here's a rough diagram I drew (based on standard FWE geometry) of a possible scenario that would make this happen. I suspect that something like this is what you're observing. With the right tools, you could actually measure this. Note that the pattern I drew here is not "to scale" - it's just a made-up example to illustrate how this could happen.

The circles represent the highest pressure peak lines of the waves - same fundamental frequency, emanating from two points - the intake and exhaust. Where the peaks add together, you get highest intensity. Where a peak coincides with a trough, you get lowest intensity. It works with sound exactly like it does with light - only the wavelength is millions of times greater.

Note that the wave pressure theoretically radiates spherically from the intake and exhaust 'acoustic points' uniformly - it is NOT "shotgunned" in a particular direction, as the exhaust gas mass is !!!

L Cottrill
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phase_0_w100.jpg
A possible scenario for the layout of noise around a valveless engine (FWE shown). Drawing Copyright 2005 Larry Cottrill
phase_0_w100.jpg (74.87 KiB) Viewed 15601 times

Mike Everman
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re: Materials Science

Post by Mike Everman » Thu Feb 02, 2006 2:55 pm

Oooh, that's a nice one, Ben. I may have to plot that for fun.
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Mark
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re: Materials Science

Post by Mark » Fri Feb 03, 2006 8:15 am

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pezman
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re: Materials Science

Post by pezman » Sat Feb 25, 2006 5:00 pm

That Rand Cam engine is pure genius. I was thinking of something like that a while back, but didn't come up with the missing pieces of the puzzle - the center part of the engine and the moving vanes.

Thanks for that post!

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re: Materials Science

Post by pezman » Sat Feb 25, 2006 7:37 pm

The Rand Cam and some of its cousins:
Rand Cam
Ball Piston Engine

A.S. Hybrid Engine
Quasi Turbine

I've some across some of these guys before, but figured I'd collect them together and make a post. Not a complete list, by any means ...

I was interested in finding a diagram of the Janova engine, but came up dry (not that it was a diligent search).
Last edited by pezman on Sat Feb 25, 2006 7:59 pm, edited 2 times in total.

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